ag-490 and Disease-Models--Animal

Ulcerative colitis (UC) is a chronic inflammatory bowel disease. Several studies have demonstrated that α7 nicotinic acetylcholine receptors (α7nAChRs) exert anti-inflammatory effects on immune cells and nicotine suppress UC onset and relapse. Plasmacytoid dendritic cells (pDCs) reportedly accumulate in the colon of UC patients. Therefore, we investigated the pathophysiological roles of α7nAChRs on pDCs in the pathology of UC using oxazolone (OXZ)-induced Th2-type colitis with BALB/c mice. 2-deoxy-D-glucose, a central vagal stimulant suppressed OXZ colitis, and nicotine also ameliorated OXZ colitis with suppressing Th2 cytokines, which was reversed by α7nAChR antagonist methyllycaconitine. Additionally, α7nAChRs were expressed on pDCs, which were located very close to cholinergic nerve fibers in the colon of OXZ mice. Furthermore, nicotine suppressed CCL21-induced bone marrow-derived pDC migration due to Rac 1 inactivation, which was reversed by methyllycaconitine, a JAK2 inhibitor AG490 or caspase-3 inhibitor AZ-10417808. CCL21 was mainly expressed in the isolated lymphoid follicles (ILFs) of the colon during OXZ colitis. The therapeutic effect of cholinergic pathway on OXZ colitis probably through α7nAChRs on pDCs were attributed to the suppression of pDC migration toward the ILFs. Therefore, the activation of α7nAChRs has innovative therapeutic potential for the treatment of UC.

Topics: Aconitine; alpha7 Nicotinic Acetylcholine Receptor; Animals; Anti-Inflammatory Agents; Caspase 3; Caspase Inhibitors; Central Nervous System Stimulants; Cholinergic Neurons; Colitis, Ulcerative; Colon; Dendritic Cells; Deoxyglucose; Disease Models, Animal; Enzyme Inhibitors; Janus Kinase 2; Mice, Inbred BALB C; Neuroimmunomodulation; Neuropeptides; Nicotine; Oxazolone; rac1 GTP-Binding Protein; STAT3 Transcription Factor; Th2 Cells; Tyrphostins; Vagus Nerve

Parkinson's disease (PD) is characterized by motor impairment and dopaminergic neuronal loss. There is no cure for the disease, and treatments have several limitations. The transient receptor potential melastatin 2 (TRPM2), a calcium-permeable non-selective cation channel, has been reported to be upregulated in neuronal death. However, there are no in vivo studies evaluating TRPM2's role and neuroprotective effects in PD. Here, we test the hypothesis that TRPM2 is upregulated in the 6-hydroxydopamine (6-OHDA) mouse model of PD and that its inhibition, by the AG490, is neuroprotective. For that, AG490 or vehicle were intraperitoneally administered into C57BL/6 mice. Mice then received 6-OHDA into the right striatum. Motor behavior assessments were evaluated 6, 13, and 20 days after surgery using the cylinder and apomorphine-induced rotational testes, and 7, 14, and 21 days after surgery using rotarod test. Brain samples of substantia nigra (SNc) and striatum (CPu) were collected for immunohistochemistry and immunoblotting on days 7 and 21. We showed that TRPM2 protein expression was upregulated in 6-OHDA-treated animals. In addition, AG490 prevented dopaminergic neuron loss, microglial activation, and astrocyte reactivity in 6-OHDA-treated animals. The compound improved motor behaviors and Akt/GSK-3β/caspase-3 signaling. We conclude that TRPM2 inhibition by AG490 is neuroprotective in the 6-OHDA model and that the TRPM2 channel may represent a potential therapeutic target for PD.

Topics: Animals; Disease Models, Animal; Dopaminergic Neurons; Glycogen Synthase Kinase 3 beta; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Oxidopamine; Parkinson Disease; Substantia Nigra; TRPM Cation Channels; Tyrphostins

Osteoarthritis (OA) is a complex chronic inflammatory disease characterized by articular degeneration and pain. Recent studies have identified interleukin 6 (IL-6) as a potential mediator leading to OA, but the therapeutic effects of inhibiting IL-6 signaling in intreating OA need to be further clarified. Here, we identified the intracellular signal transduction induced by recombinant IL-6 and focused on the impact of tyrphostin AG490 (a JAK2 inhibitor) on cartilage degeneration and OA pain. We found that IL-6 increased the inflammatory cytokines production and hypertrophic markers expression of primary mouse chondrocytes by activating JAK2/STAT3. Meanwhile, tyrphostin AG490 significantly attenuated articular degeneration and osteophyte formation in experimental mice with anterior cruciate ligament transection (ACLT) surgery. In vivo electrophysiological experiments showed that articular stimulation of IL-6 induced spinal hyperexcitability, which was prevented by coinjection of tyrphostin AG490. Specifically, compared with DMSO-treated ACLT mice, tyrphostin AG490 improved ambulate activity of mice and abolished the enhancement of serum bradykinin induced by IL-6. Together, we suggest that tyrphostin AG490 protected against progression of OA and improved OA prognosis by reducing cartilage degeneration and arthritis pain. Our findings provide further evidence for targeting IL-6 signaling in the treatment of OA.

Topics: Animals; Cartilage, Articular; Chondrocytes; Disease Models, Animal; Interleukin-6; Osteoarthritis; Pain; Tyrphostins

Topics: Animals; Apoptosis; Cell Survival; Cells, Cultured; Disease Models, Animal; Janus Kinase 2; L-Lactate Dehydrogenase; Male; Membrane Potential, Mitochondrial; Mice; Mice, Inbred C57BL; Myocardial Reperfusion Injury; Myocytes, Cardiac; Peptides; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

Acute immune rejection is one of the most serious complications of heart transplantation, and its mechanism has always been a hot spot. Th17 cells and cytokine interleukin-17 (IL-17) have been proved to be involved in acute immune rejection, and the signaling pathway mechanism has attracted our interest. It has been confirmed that the Janus kinase 2-signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway is involved in the differentiation of CD4+ T cells, so we focus on whether the JAK2/STAT3 signaling pathway is involved in the occurrence of acute immune rejection by regulating the Th17/IL-17 axis. In this study, we used Bagg's Albino c mice and C57BL/6 mice to construct heterotopic heart transplantation models, which were divided into the acute rejection group and AG490-treated group (n = 5), and donor tissue and serum were collected in 3 experimental days from the recipient mice for H&E staining analysis of paraffin sections and ELISA, Western blot, flow cytometry, and real time-polymerase chain reaction. The results showed that the acute rejection rating of the heart decreased, and the expression of related factors decreased significantly after using the inhibitor AG490, suggesting that the JAK2/STAT3 signaling pathway regulates expression of the Th17/IL-17 axis in cardiac allograft rejection.

Topics: Animals; Disease Models, Animal; Graft Rejection; Graft Survival; Heart Transplantation; Immunosuppressive Agents; Interleukin-17; Janus Kinase 2; Janus Kinase Inhibitors; Male; Mice, Inbred C57BL; Myocardium; Signal Transduction; STAT3 Transcription Factor; Th17 Cells; Transplantation, Heterotopic; Tyrphostins

Sepsis-induced myocardial dysfunction (SIMD) represents one of the serious complications secondary to sepsis, which is a leading cause of the high mortality rate among septic cases. Subsequent cardiomyocyte apoptosis, together with the uncontrolled inflammatory response, has been suggested to be closely related to SIMD. Piceatannol (PIC) is verified with potent anti-apoptotic and anti-inflammatory effects, but its function and molecular mechanism in SIMD remain unknown so far. This study aimed to explore the potential role and mechanism of action of PIC in resisting SIMD. The interaction of PIC with JAK2 proteins was evaluated by molecular docking, molecular dynamics (MD) simulation and surface plasmon resonance imaging (SPRi). The cecal ligation and puncture-induced septicemia mice and the LPS-stimulated H9C2 cardiomyocytes were prepared as the models in vivo and in vitro, separately. Molecular docking showed that JAK2-PIC complex had the -8.279 kcal/mol binding energy. MD simulations showed that JAK2-PIC binding was stable. SPRi analysis also showed that PIC has a strong binding affinity to JAK2. PIC treatment significantly ameliorated the cardiac function, attenuated the sepsis-induced myocardial loss, and suppressed the myocardial inflammatory responses both in vivo and in vitro. Further detection revealed that PIC inhibited the activation of the JAK2/STAT3 signaling, which was tightly associated with apoptosis and inflammation. Importantly, pre-incubation with a JAK2 inhibitor (AG490) partially blocked the cardioprotective effects of PIC. Collectively, the findings demonstrated that PIC restored the impaired cardiac function by attenuating the sepsis-induced apoptosis and inflammation via suppressing the JAK2/STAT3 pathway both in septic mice and H9C2 cardiomyocytes.

Topics: Animals; Apoptosis; Cardiomyopathies; Cardiotonic Agents; Cell Line; Disease Models, Animal; Inflammation; Janus Kinase 2; Male; Mice, Inbred C57BL; Molecular Docking Simulation; Molecular Dynamics Simulation; Myocytes, Cardiac; Rats; Sepsis; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Tyrphostins

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Plasma cell mastitis (PCM) is a special form of mastitis characterized by periductal inflammation and large-scale plasma cell infiltration. At present, the recurrence rate of PCM after excision is quite high, making PCM a major problem for mammary surgeons. However, no effective drug exists for the treatment of PCM. Numerous studies have demonstrated that Sinomenine hydrochloride (SH) has potent anti-inflammatory and immunoregulatory properties. However, the efficacy and the underlying mechanisms of SH in the treatment of PCM remain unclear. In the present study, we first investigated the therapeutic effects of SH in the PCM mouse model and clarified the possible mechanisms. We found that the levels of plasmocytes and lymphocytes infiltration were alleviated significantly in the 100 mg/kg SH group compared to the control group. In addition, few CD138+ plasma cells were found in the mammary glands of the 100 mg/kg SH group. The levels of Bcl-2 in the 100 mg/kg SH group were dramatically decreased compared with those in the saline group. Mechanistically, we demonstrated that SH inhibited the progression of PCM mainly through downregulating IL-6/JAK2/STAT3 levels. Collectively, our results suggested that SH could inhibit the progression of PCM by suppressing IL-6/JAK2/STAT3 cascades and ultimately achieve a therapeutic effect in PCM. This study provides theoretical support for the clinical application of SH in the treatment of PCM.

Topics: Animals; Anti-Inflammatory Agents; Disease Models, Animal; Disease Progression; Female; Humans; Interleukin-6; Janus Kinase 2; Mammary Glands, Animal; Mastitis; Mice; Morphinans; Plasma Cells; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Disease Models, Animal; Enzyme Inhibitors; Hydrogen Peroxide; Infarction, Middle Cerebral Artery; Janus Kinase 2; Mice; Neuroblastoma; Oxidants; Oxidative Stress; Rats; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

There is a major clinical need for new therapies for the treatment of chronic itch. Many of the molecular components involved in itch neurotransmission are known, including the neuropeptide NPPB, a transmitter required for normal itch responses to multiple pruritogens in mice. Here, we investigated the potential for a novel strategy for the treatment of itch that involves the inhibition of the NPPB receptor NPR1 (natriuretic peptide receptor 1). Because there are no available effective human NPR1 (hNPR1) antagonists, we performed a high-throughput cell-based screen and identified 15 small-molecule hNPR1 inhibitors. Using in vitro assays, we demonstrated that these compounds specifically inhibit hNPR1 and murine NPR1 (mNPR1). In vivo, NPR1 antagonism attenuated behavioral responses to both acute itch- and chronic itch-challenged mice. Together, our results suggest that inhibiting NPR1 might be an effective strategy for treating acute and chronic itch.

Topics: Animals; Behavior, Animal; Cell-Free System; Dermatitis, Contact; Disease Models, Animal; Ganglia, Spinal; Humans; Mice, Inbred C57BL; Mice, Knockout; Neurons; Pruritus; Receptors, Atrial Natriuretic Factor; Reproducibility of Results; Signal Transduction; Small Molecule Libraries

The Janus activated kinase 2 (JAK2)/signal transducer and the activator of transcription 3 (STAT3) pathway are involved in many physiological processes, such as cell survival, inflammation, development, proliferation and differentiation. Increasing evidence has shown that this pathway also has neuron-specific functions in the central nervous system. In this study, the functional significance of the JAK2/STAT3 signaling pathway in nerve cell apoptosis in rats with white matter injury was evaluated.. The rat model of white matter injury was established by ligating bilateral common carotid arteries, and the changes of the JAK2 and STAT3 phosphorylation in hippocampal neurons were evaluated using the immunohistochemistry. In addition, the effects of JAK2 inhibitor AG490 and STAT3 small interfering ribonucleic acids (siRNAs) on the expression of phosphorylated-JAK2 (pJAK2), STAT3 messenger RNAs (mRNAs) and pSTAT3 in hippocampal neurons of white matter injury rats were studied. The effects of both on cerebral infarction volume and neuron apoptosis in white matter injury rats were also investigated.. The expression of pJAK2 and pSTAT3 were significantly increased after white matter injury in rats (p<0.05). JAK2 inhibitor AG490 markedly decreased the phosphorylation of JAK2 and STAT3 in hippocampal neurons in the model group (p<0.05). STAT3 siRNAs remarkably reduced the expression levels of STAT3 mRNA and protein in hippocampus neurons in the model group (p<0.05), while having no effect on the expression level of pJAK2 protein. AG490 and STAT3 siRNAs notably attenuated the volume of cerebral infarction in the model group, as well as reduced neuron apoptosis after white matter injury.. The inhibition of the JAK2/STAT3 signaling pathway contributed to reducing the volume of cerebral infarction and neuron apoptosis in rats with white matter injury.

Topics: Animals; Apoptosis; Cell Survival; Cerebral Infarction; Disease Models, Animal; Hippocampus; Humans; Janus Kinase 2; Male; Neurons; Phosphorylation; Rats; RNA, Small Interfering; Signal Transduction; STAT3 Transcription Factor; Tyrphostins; White Matter

Painful diabetic neuropathy (PDN) is a severely debilitating chronic pain syndrome. Spinal chemokine CXCL13 and its receptor CXCR5 were recently demonstrated to play a pivotal role in the pathogenesis of chronic pain induced by peripheral tissue inflammation or nerve injury. In this study we investigated whether CXCL13/CXCR5 mediates PDN and the underlying spinal mechanisms. We used the db/db type 2 diabetes mice, which showed obvious hyperglycemia and obese, long-term mechanical allodynia, and increased expression of CXCL13, CXCR5 as well as pro-inflammatory cytokines TNF-α and IL-6 in the spinal cord. Furthermore, in the spinal cord of db/db mice there is significantly increased gliosis and upregulated phosphorylation of cell signaling kinases, including pERK, pAKT and pSTAT3. Mechanical allodynia and upregulated pERK, pAKT and pSTAT3 as well as production of TNF-α and IL-6 were all attenuated by the noncompetitive NMDA receptor antagonist MK-801. If spinal giving U0126 (a selective MEK inhibitor) or AG490 (a Janus kinase (JAK)-STAT inhibitor) to db/db mice, both of them can decrease the mechanical allodynia, but only inhibit pERK (by U0126) or pSTAT3 (by AG490) respectively. Acute administration of CXCL13 in C57BL/6J mice resulted in exacerbated thermal hyperalgesia and mechanical allodynia, activation of the pERK, pAKT and pSTAT3 pathways and increased production of pro-inflammatory cytokines (IL-1β, TNF-α and IL-6), which were all attenuated by knocking out of Cxcr5. In all, our work showed that chemokine CXCL13 and its receptor CXCR5 in spinal cord contribute to the pathogenesis of PDN and may help develop potential novel therapeutic approaches for patients afflicted with PDN.

Topics: Animals; Butadienes; Chemokine CXCL13; Cytokines; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Disease Models, Animal; Dizocilpine Maleate; Hyperalgesia; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Nitriles; Proto-Oncogene Proteins c-akt; Receptors, CXCR5; Signal Transduction; Spinal Cord; STAT3 Transcription Factor; Tyrphostins

The aim of this study was to investigate the influences of propofol on myocardial ischemia/reperfusion injury in rats through the Janus kinase/signal transducers and the activators of transcription (JAK/STAT) signaling pathway.. A total of 48 Sprague-Dawley (SD) rats were randomly divided into four groups, including: the sham-operation group (n=12), the model group (n=12), the propofol group (n=12) and the inhibitor group (n=12). The rats in the sham-operation group only received thoracotomy, without the modeling of the ischemia/reperfusion injury. The model of myocardial ischemia/reperfusion injury was established in the rats of the model group, and the rats were given normal saline for intervention. The rats in the propofol group were utilized to prepare the model of myocardial ischemia/reperfusion injury and were intervened with propofol. Meanwhile, the rats in the inhibitor group received intervention with AG490 after the establishment of myocardial ischemia/reperfusion injury model. Immunohistochemistry was applied to detect the expressions of B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax). Western blotting was utilized to measure the relative protein expressions of phosphorylated JAK2 (p-JAK2) and p-STAT3. The messenger ribonucleic acid (mRNA) expressions of Bax and Bcl-2 were determined via quantitative Polymerase Chain Reaction (qPCR). Furthermore, cell apoptosis was examined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.. Immunohistochemistry results showed that compared with the sham-operation group, the positive expression of Bax remarkably increased (p<0.05), while Bcl-2 notably decreased (p<0.05) in the model group, propofol group, and inhibitor group. The propofol group and inhibitor group showed a significant lower positive expression of Bax (p<0.05) and evident higher positive expression of Bcl-2 (p<0.05) when compared with the model group. However, there were no significant differences in the positive expressions of Bax and Bcl-2 between the propofol group and inhibitor group (p>0.05). According to the results of Western blotting, the relative protein expression levels of p-JAK2 and p-STAT3 proteins were remarkably elevated in the model group, propofol group and inhibitor group in comparison with those in the sham-operation group (p<0.05). Propofol group and inhibitor group exhibited remarkably lower protein expression levels of p-JAK2 and p-STAT3 compared with the model group (p<0.05). However, no significant differences were observed in the protein expressions of p-JAK2 and p-STAT3 between propofol group and inhibitor group (p>0.05). The results of qPCR manifested that the mRNA expression of Bax was notably higher (p<0.05), whereas Bcl-2 was significantly lower (p<0.05) in the model group, propofol group and inhibitor group than those of the sham-operation group. Compared with the model group, the mRNA expression of Bax was evidently declined (p<0.05), while Bcl-2 was significantly elevated (p<0.05) in the propofol group and inhibitor group. Meanwhile, there were no evident differences in the mRNA expressions of Bax and Bcl-2 between the propofol group and inhibitor group (p>0.05). Subsequent TUNEL assay indicated that the model group, propofol group, and inhibitor group showed remarkably higher apoptosis rate than the sham-operation group (p<0.05). Moreover, the apoptosis rate was remarkably reduced in the propofol group and inhibitor group in comparison with the model group (p<0.05). However, no significant difference was observed in the apoptosis rate between propofol group and inhibitor group (p>0.05).. Propofol inhibits myocardial cell apoptosis after myocardial ischemia/reperfusion injury by repressing the JAK/STAT signaling pathway.

Topics: Animals; Disease Models, Animal; Gene Expression Regulation; Janus Kinase 2; Male; Myocardial Reperfusion Injury; Phosphorylation; Propofol; Random Allocation; Rats; Rats, Sprague-Dawley; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

The transmembrane chemokine (C-X-C motif) ligand 16 (CXCL16) plays a vital role in the pathogenesis of organ fibrosis, including the liver and kidney. However, the detailed biological function of CXCL16 is still not fully understood in the progression of pulmonary fibrosis (PF). The aim of present study is to examine the function of CXCL16 in PF.. In this study, we constructed the PF model on mouse by using bleomycin and analyzed the effect of the mouse recombinant protein CXCL16 on mouse lung fibroblast L929 (LF) as well. To further examine the connection between CXCL16 and STAT3 in mouse LF cells, the STAT3 inhibitor AG490 was utilized to inhibit the expression of STAT3. Meanwhile, lipopolysaccharide was used to enhance the phosphorylation of STAT3 (p-STAT3) in mouse LF cells.. Our results indicated that the level of CXCL16/CXCR6 was significantly upregulated in the mouse PF model. Moreover, the level of p-STAT3 was also promoted. In addition, the mouse recombinant protein CXCL16 not only contributed to the proliferation of mouse LF cells but also induced the expression of p-STAT3 in LF cells. However, the effect of CXCL16 was deeply abolished by the STAT3 inhibitor AG490 in LF cells. Meanwhile, the antibody of CXCL16 deeply reduced the phosphorylation of STAT3 in lipopolysaccharide (LPS) cultured cells.. All these results demonstrated that CXCL16 promoted the phosphorylation of STAT3 and further demonstrated that STAT3 was a critical component in CXCL16/CXCR6 signaling pathway. This research not only enhanced the comprehension of CXCL16 but also indicated its potential value as a target in the treatment for human PF.

Topics: Animals; Case-Control Studies; Cell Line; Chemokine CXCL16; Disease Models, Animal; Disease Progression; Lipopolysaccharides; Male; Mice; Phosphorylation; Pulmonary Fibrosis; STAT3 Transcription Factor; Tyrphostins

Ginkgolide K (GK) is a new compound extracted from the leaves of Ginkgo biloba, which has been recognized to exert anti-oxidative stress and neuroprotective effect on ischemic stroke. While whether it plays an enhanced effect on angiogenesis during ischemic stroke remains unknown. The aim of this study was to investigate the effect of ginkgolide K on promoting angiogenesis as well as the protective mechanism after cerebral ischemia-reperfusion. Using the transient middle cerebral artery occlusion (tMCAO) mouse model, we found that GK (3.5, 7.0, 14.0 mg/kg, i.p., bid., 2 weeks) attenuated neurological impairments, and promoted angiogenesis of injured ipsilateral cortex and striatum after 14 days of cerebral ischemia-reperfusion in mice. Further, GK (3.5 mg/kg in vivo, 10 μM in vitro) significantly up-regulated the expressions of HIF-1α and VEGF in tMCAO mouse brains and in b End3 cells after OGD/R, and GK-induced upregulation of HIF-1α and VEGF in b End3 cells could be abolished by JAK2/STAT3 inhibitor AG490. Our results demonstrate that GK promotes angiogenesis after ischemia stroke through increasing the expression of HIF-1α/VEGF via JAK2/STAT3 pathway, which provide an insight into the novel clinical application of GK and its analogs in ischemic stroke therapy in future.

Topics: Animals; Brain; Disease Models, Animal; Ginkgo biloba; Ginkgolides; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Infarction, Middle Cerebral Artery; Janus Kinase 2; Lactones; Male; Mice; Mice, Inbred C57BL; Middle Cerebral Artery; Neovascularization, Physiologic; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor; Tyrphostins; Vascular Endothelial Growth Factor A

Accounting for high mortality and morbidity rates, intracerebral hemorrhage (ICH) remains one of the most detrimental stroke subtypes lacking a specific therapy. Neuroinflammation contributes to ICH-induced brain injury and is associated with unfavorable outcomes. This study aimed to evaluate whether

Topics: alpha7 Nicotinic Acetylcholine Receptor; Animals; Blood Transfusion, Autologous; Brain Injuries; Bridged Bicyclo Compounds, Heterocyclic; Cerebral Hemorrhage; Collagenases; Disease Models, Animal; Humans; Inflammation; Janus Kinase 2; Mice; Neurons; Peroxidase; Quinuclidines; Rats; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha; Tyrphostins

This study aimed to evaluate the protective effect and mechanisms of remote limb ischaemic postconditioning (RIPostC) against myocardial ischaemia/reperfusion (IR) injury.. Male mice underwent 45 min of coronary artery occlusion followed by 2 h of reperfusion. RIPostC was achieved by three cycles of 5 min of ischaemia and 5 min of reperfusion in the left hind limb at the start of the reperfusion period. After 2 h of cardiac reperfusion, myocardial infarct size, cardiac enzyme release, apoptosis and oxidative stress were assessed. Protein expression and phosphorylation were measured by Western blotting.. RIPostC significantly decreased cardiac IR injury, as reflected by reduced infarct size and cellular apoptosis (22.9 ± 3.3% vs 40.9 ± 6.2% and 13.4% ± 3.1% vs 26.2% ± 3.1%, respectively, both P < 0.01) as well as plasma creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) release (21.97 ± 4.08 vs 35.86 ± 2.91 ng/ml and 6.17 ± 0.58 vs 8.37 ± 0.89 U/ml, respectively, both P < 0.01) compared with the IR group. RIPostC significantly increased the phosphorylation of myocardial STAT3, Akt and eNOS (P < 0.01). In addition, RIPostC elevated the nuclear translocation of Nrf2 and the expression of HO-1 and reduced myocardial oxidative stress (P < 0.05). Interestingly, pretreatment with the JAK/STAT3 inhibitor AG490 blocked the cardioprotective effect of RIPostC accompanied by decreased phosphorylation of myocardial STAT3, Akt and eNOS (P < 0.05), decreased nuclear translocation of Nrf2 and expression of HO-1, as well as increased oxidative stress (P < 0.05).. RIPostC attenuates apoptosis and protects against myocardial IR injury, possibly through the activation of JAK/STAT3-mediated Nrf2-antioxidant signalling.

Topics: Animals; Antioxidants; Apoptosis; Coronary Vessels; Creatine Kinase, MB Form; Disease Models, Animal; Ischemic Postconditioning; L-Lactate Dehydrogenase; Male; Mice; Mice, Inbred C57BL; Myocardial Reperfusion Injury; NF-E2-Related Factor 2; Nitric Oxide Synthase Type III; Oxidative Stress; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; STAT3 Transcription Factor; Superoxides; Tyrphostins

The present study aims to investigate the protective effects of the SOCS1-JAK2-STAT3 signaling pathway on neurons in a rat model of ischemic stroke.. Our study was conducted using an ischemic stroke rat model. After the microglia were extracted, 40 neonatal Sprague-Dawley (SD) rats were assigned into the blank, AG490, model and negative control (NC) groups. The neurological function of all the rats was evaluated. Histopathological changes were observed. qRT-PCR and western blotting were applied to measure the expression of genes and proteins in the SOCS1-JAK2-STAT3 signaling pathway and related to apoptosis. The TUNEL assay was conducted to calculate the cellular morphology and apoptosis of neuronal cells. Cell viability was detected using the MTT assay. In addition, immunoassays were used to measure the content of superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) as well as the levels of oxidative stress.. Compared with the blank group, the model and NC groups showed higher neurological function scores-the cytoplasm of the neurons were cavitated, the organelles were reduced with unclear margins, some of the neurons were necrotic, and apoptosis was increased. In addition, the NC and model groups exhibited decreased cell viability, lower mRNA and protein expression of SOCS1 SOCS3 and bcl-2 and reduced SOD and GSH levels but higher mRNA and protein expression levels of AK2, STAT3,Bax and caspase-3 as well as increased protein expression of P-JAK2, P-STAT3 and activated caspase-3 (c-caspase-3). Moreover, the MDA levels were up-regulated in the NC and model groups. In contrast, opposing trends were found in the AG490 group compared with the NC and model groups.. These data demonstrate that inhibiting the SOCS1-JAK2-STAT3 signaling pathway can reduce the loss of nerve function and apoptosis of neuronal cells, which provides a new target for the clinical treatment of ischemic stroke.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Disease Models, Animal; Glutathione; Janus Kinase 2; Male; Malondialdehyde; Neurons; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Signal Transduction; STAT3 Transcription Factor; Stroke; Superoxide Dismutase; Suppressor of Cytokine Signaling 1 Protein; Tyrphostins

Traumatic brain injury (TBI) is induced by complex primary and secondary mechanisms that give rise to cell death, inflammation, and neurological dysfunction. Understanding the mechanisms that drive neurological damage as well as those that promote repair can guide the development of therapeutic drugs for TBI. Kruppel-like factor 4 (KLF4) has been reported to negatively regulate axon regeneration of injured retinal ganglion cells (RGCs) through inhibition of JAK-STAT3 signaling. However, the role of KLF4 in TBI remains unreported. Reactive oxygen species (ROS)-induced neuronal death is a pathophysiological hallmark of TBI.. In this study, we used H. The results show that H. These findings provide evidence that KLF4 plays an important role in the pathophysiology of TBI. Blocking KLF4 may be a potential therapeutic strategy for the treatment of TBI, either alone or in combination with agents that target complementary mechanisms.

Topics: Animals; Apoptosis; Brain Injuries, Traumatic; Cerebral Cortex; Cyclin D1; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; Hydrogen Peroxide; Janus Kinases; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Nerve Regeneration; Optic Nerve Injuries; Rats; Rats, Sprague-Dawley; Retinal Ganglion Cells; Signal Transduction; STAT3 Transcription Factor; Tumor Suppressor Protein p53; Tyrphostins

AG490, the specific inhibitor of JAK2/STAT3 signaling, has been shown to decrease portal pressure, splanchnic hyperdynamic circulation and liver fibrosis in cirrhotic rats. Nonselective betablockers such as propranolol are the only drugs recommended in the treatment of portal hypertension. The aim of this study was to explore the combinative effect of treatment with propranolol and AG490 on portal hypertension.. Rats induced by common bile duct ligation were treated with vehicle, AG490, propranolol, or AG490 + propranolol for 2 weeks. Hemodynamics parameters were assessed. Expressions of phospho-STAT3 protein and its down-regulated cytokines in splanchnic organs were detected by ELISA or western blot. Lipopolysaccharide binding protein (LBP) and IL-6 were assessed by ELISA or western blot. Characterization of liver and mesentery was performed by histological analyses.. Highly expressed phospho-STAT3 protein in cirrhotic rats could successfully be inhibited by AG490 or AG490 + propranolol treatments but not by propranolol alone. Both AG490 and propranolol significantly reduced portal pressure and hyperdynamic splanchnic circulation, and combination of AG490 and propranolol achieved an additive effect than with either drug alone. AG490, alone or in combination with propranolol, inhibited liver fibrosis, splenomegaly and splanchnic angiogenesis. Increased markers of bacterial translocation (LBP and IL6) were greatly reduced by propranolol but not by AG490.. The combination of propranolol and AG490 caused a greater improvement of portal hypertension and might therefore offer a potentially promising therapy in the portal hypertension treatment.

Topics: Acute-Phase Proteins; Adrenergic beta-Antagonists; Animals; Antihypertensive Agents; Bacterial Translocation; Carrier Proteins; Common Bile Duct; Disease Models, Animal; Drug Therapy, Combination; Hypertension, Portal; Interleukin-6; Intestinal Mucosa; Intestines; Ligation; Liver; Liver Cirrhosis, Biliary; Male; Membrane Glycoproteins; Neovascularization, Pathologic; Phosphorylation; Portal Pressure; Propranolol; Protein Kinase Inhibitors; Rats, Sprague-Dawley; Splanchnic Circulation; Spleen; STAT3 Transcription Factor; Tyrphostins

Emerging data has suggested a high prevalence of osteoarthritis (OA) among obese people. As an important adipokine secreted by white adipose tissue, leptin may be a key mediator in the progression of OA. Leptin exerts a catabolic effect on OA cartilage by increasing the production of metalloproteinase (MMP) enzymes, and contributes to apoptosis in chondrocytes. The current study aimed to explore the role of leptin on the apoptosis of chondrocytes in OA, and its underlying mechanisms. In the in vitro model of OA used in the present study, administration of exogenous leptin induced the generation of reactive oxygen species (ROS) and apoptosis in chondrocytes. It has been demonstrated that leptin is associated with the pathogenesis of OA via the Janus kinase 2 (JAK2)‑signal transducer and activator of transcription 3 (STAT3) signaling pathway, and data gathered in the present study demonstrated that suppression of this signaling pathway using a JAK2 inhibitor, AG490, significantly ameliorated leptin‑induced apoptosis in damaged chondrocytes in vitro, and reduced the generation of ROS. Furthermore, the protein expression levels of MMP‑13 and B‑cell lymphoma 2‑associated X protein were downregulated in the AG490‑treated group. The results of the present study may provide insight into the underlying molecular mechanism by which leptin induces apoptosis in chondrocytes. These findings indicated the importance of leptin as a therapeutic target for the treatment of OA in the overweight population.

Topics: Animals; Anterior Cruciate Ligament; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Cells, Cultured; Chondrocytes; Disease Models, Animal; Down-Regulation; Janus Kinase 2; Leptin; Male; Matrix Metalloproteinase 13; Osteoarthritis; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

Interleukin-17A, a pro-inflammatory cytokine, has a direct proapoptotic effect on cardiomyocytes. However, the specific mechanism has not been clarified. In the present study, an in-vitro model of cardiomyocyte apoptosis induced by IL-17A stimulation was employed and the roles of iNOS and Stat3 involved were investigated. Our data showed that the neonatal mouse cardiomyocytes express IL-17 receptors: IL-17RA and IL-17RC, but did not express IL-17A. Exogenous IL-17A significantly induces iNOS expression and hence the cardiomyocyte apoptosis. Moreover, IL-17A-induced cardiomyocyte apoptosis can be achieved directly via iNOS activation. We further showed that exogenous IL-17A simultaneously triggers Stat3 activation, which in turn inhibits IL-17A-induced iNOS expression in cardiomyocytes. And both ChIP and dual-luciferase results confirmed that Stat3 directly inhibits transcriptional activities of iNOS via binding to its specific promoter region. Consistent with these data, silencing of Stat3 in fact can aggravate IL-17A-triggered cardiomyocyte apoptosis. Finally, using an in vivo myocardial ischemia/reperfusion injury model, we verified that Stat3 inhibition increased iNOS expression and exacerbated cardiomyocyte apoptosis. Thus, our data strongly support the notion that Stat3 plays a compensatory anti-apoptotic role in IL-17A/iNOS-mediated cardiomyocyte apoptosis via inhibiting iNOS transcription, providing a novel molecular mechanism of apoptosis regulation and complicated interactions between IL-17A/iNOS and IL-17A/Stat3 signalings.

Topics: Animals; Apoptosis; Binding Sites; Cells, Cultured; Disease Models, Animal; Interleukin-17; Male; Mice, Inbred C57BL; Myocardial Infarction; Myocardial Reperfusion Injury; Myocytes, Cardiac; Nitric Oxide Synthase Type II; Phosphorylation; Promoter Regions, Genetic; Receptors, Interleukin-17; Signal Transduction; STAT3 Transcription Factor; Time Factors; Transfection; Tyrphostins

The present study aimed to investigate the effects of the JAK2/STAT3/SOSC1 signaling pathway on the secretion function of vascular endothelial cells (VECs) in a rat model of pregnancy-induced hypertension (PIH).. A PIH rat model was established. Forty-eight pregnant Sprague-Dawley female rats were selected and assigned into four groups: the normal group (normal non-pregnant rats), the non-PIH group (pregnant rats without PIH), the PIH group (pregnant rats with PIH) and the AG490 group (pregnant rats with PIH treated with AG490). Systolic blood pressure (SBP) and urinary protein (UP) were measured. The expressions of JAK2/STAT3/SOSC1 signaling pathway-related proteins in placenta tissues were detect by Western blotting. Radioimmunoassay was applied to detect serum levels of nitric oxide (NO), super oxide dismutase (SOD), placental growth factor (PGF), thromboxane B2 (TXB2) and endothelin (ET). Enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α).. Compared with the normal and non-PIH groups, the PIH and AG490 groups had higher SBP and UP levels at 17th and 25th day of pregnancy. The expressions of p/t-JAK2, p/t-STAT3 and SOSC1 in the PIH and AG490 groups were higher than those in the non-PIH group, while the expressions of p/t-JAK2, p/t-STAT3 and SOSC1 in the AG490 group were lower than those in the PIH group. Compared with the non-PIH group, serum levels of ET, TXB2, IL-6 and TNF-α were increased in the PIH and AG490 groups, while serum levels of NO, SOD, 6-keto-PGF1a and IL-10 levels were reduced. Furthermore, the AG490 had lower serum levels of ET, TXB2, IL-6 and TNF-α and higher serum levels of NO, SOD, 6-keto-PGF1a and IL-10 than those in the PIH group.. Our study provides evidence that inhibition of the JAK2/STAT3/SOSC1 signaling pathway could improve the secretion function of VECs in PIH rats.

Topics: Animals; Blood Pressure; Disease Models, Animal; Endothelial Cells; Female; Fetus; Hypertension, Pregnancy-Induced; Janus Kinase 2; Kidney; Male; Placenta; Pregnancy; Proteinuria; Rats, Sprague-Dawley; Signal Transduction; STAT3 Transcription Factor; Suppressor of Cytokine Signaling 1 Protein; Systole; Tyrphostins

Astrocytes play an important role in the pathogenesis of glaucoma. Abnormal activation and/or proliferation of astrocytes, termed astrogliosis, have been observed during optic nerve degeneration. Our previous study identified signal transducer and activator of transcription 3 (STAT3) signaling as an important regulator of astrogliosis in the optic nerve in a rat transient ischemia/reperfusion model. In this study, we used pharmacological inhibition of STAT3 activation in the same model to assess whether it could attenuate reactive astrogliosis and to observe its influence on optic nerve damage and retinal ganglion cell (RGC) damage. Our findings show that retrobulbar inhibition of STAT3 in optic nerve head astrocytes leads to (a) increased nerve fiber bundle survival in the optic nerve, (b) increased nerve fiber bundle and RGC survival in the retina, (c) decreased astrocyte reactivation in the optic nerve (d) decreased remodeling of astrocytes in the optic nerve, and (e) no influence of astrocyte reactivation inside the retina. Taken together, the Janus kinase/STAT3 pathway contributes to astrocyte reactivation in the optic nerve, which plays a pivotal role in neurodegeneration after transient ischemia/reperfusion in vivo. Inhibition of this pathway provides a potential therapeutic strategy for the treatment of glaucomatous neuropathy, and could extend to other neurodegenerative diseases.

Topics: Animals; Astrocytes; Disease Models, Animal; Drug Evaluation; Glaucoma; Gliosis; Injections, Intraocular; Janus Kinase 2; Nerve Tissue Proteins; Ocular Hypertension; Optic Disk; Optic Neuropathy, Ischemic; Protein Kinase Inhibitors; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Retinal Ganglion Cells; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

αMUPA transgenic mice spontaneously consume less food compared with their wild type (WT) ancestors due to endogenously increased levels of the satiety hormone leptin. αMUPA mice share many benefits with mice under caloric restriction (CR) including an extended life span. To understand mechanisms linked to cardiac aging, we explored the response of αMUPA hearts to ischemic conditions at the age of 6, 18, or 24 months. Mice were subjected to myocardial infarction (MI) in vivo and to ischemia/reperfusion ex vivo. Compared to WT mice, αMUPA showed functional and histological advantages under all experimental conditions. At 24 months, none of the WT mice survived the first ischemic day while αMUPA mice demonstrated 50% survival after 7 ischemic days. Leptin, an adipokine decreasing under CR, was consistently ~60% higher in αMUPA sera at baseline. Leptin levels gradually increased in both genotypes 24h post MI but were doubled in αMUPA. Pretreatment with leptin neutralizing antibodies or with inhibitors of leptin signaling (AG-490 and Wortmannin) abrogated the αMUPA benefits. The antibodies also reduced phosphorylation of the leptin signaling components STAT3 and AKT specifically in the αMUPA myocardium. αMUPA mice did not show elevation in adiponectin, an adipokine previously implicated in CR-induced cardioprotection. WT mice treated for short-term CR exhibited cardioprotection similar to that of αMUPA, however, along with increased adiponectin at baseline. Collectively, the results demonstrate a life-long increased ischemic tolerance in αMUPA mice, indicating the attenuation of cardiac aging. αMUPA cardioprotection is mediated through endogenous leptin, suggesting a protective pathway distinct from that elicited under CR.

Topics: Adipokines; Animals; Biomarkers; Cellular Senescence; Disease Models, Animal; Echocardiography; Heart Ventricles; Kaplan-Meier Estimate; Leptin; Mice; Mice, Transgenic; Myocardial Infarction; Myocardium; Proto-Oncogene Proteins c-akt; Signal Transduction; STAT3 Transcription Factor; Tyrphostins; Ventricular Function

To investigate the role of TGF-beta1 and STAT3 signaling in liver fibrosis using a rat model system and to determine the therapeutic mechanism of AG490 in relation to this signaling pathway.. Rats were randomly divided into a control group and DENA-induced liver fibrosis model group, and then subdivided into AG490 treatment groups. During fibrosis development, liver tissue samples were collected at different time points (0, 4 and 8 weeks) and evaluated according to the Scheuer scoring system. Expression of STAT3, TGFbeta1, alpha-SMA, E-cadherin, MMP2 and TIMP1 was measured by PCR (mRNA) and immunohistochemistry and western blotting (protein).. Increasing degrees of inflammation and fibrosis were observed in liver tissues of DENA-treated rats throughout model establishment. The mRNA expression of TGFbeta1 and STAT3 was significantly increased in DENA-induced rats with advanced fibrosis (AF) compared to those with early fibrosis (EF) (P = 0.034 and P = 0.012 respectively). The protein expression of TGF-beta1, phospho-Smad2, alpha-SMA, E-cadherin, STAT3 and phospho-STAT3 was significantly increased in DENA-induced rats with AF compared to the unmodeled control group (P = 0.048, P = 0.003, P = 0.002, P = 0.028, P = 0.009 and P = 0.039). The protein expression of E-cadherin was lower in the DENA-induced rats with AF than in those with EF (P = 0.026). STAT3 and TGF-beta1 co-expression was detected in AF tissues. DENA-induced AG490-treated rats with AF showed substantially lower protein expression of STAT3, TGF-beta1, MMP2 and TIMP1 compared to DENA-induced untreated rats with AF (P = 0.006, P = 0.018, P = 0.010 and P = 0.005); in addition, the degrees of fibrosis and inflammation were also greatly reduced in the DENA-induced AG490-treated rats with AF compared to DENA-induced untreated rats with AF (P = 0.042 and P = 0.021). Conclusions STAT3 signal transduction may regulate the TGF-beta1 pathway and affect liver fibrosis, especially in the advanced phase. AG490 can inhibit TGFbeta1-STAT3 signaling, resulting in reversal of liver fibrosis.

Topics: Animals; Disease Models, Animal; Liver Cirrhosis; Rats; Rats, Sprague-Dawley; Signal Transduction; STAT3 Transcription Factor; Transforming Growth Factor beta1; Tyrphostins

The functional significance for activation of inflammatory transcription factors, such as signal transducer and activator of transcription (STAT3), nuclear factor (NF)κB or NF-interleukin (IL)6 and their contribution to the induction of brain controlled sickness responses, such as fever, during infection and inflammation is unknown. Using AG490, previously shown to inhibit the STAT3- and NF-IL6-signaling pathway, we therefore investigated the central involvement of these two signaling pathways in mediating sickness behavior, fever and accompanying brain inflammation induced by peripheral lipopolysaccharide (LPS)-stimulation. Rats pre-treated i.c.v. with AG490 1 h before the i.p. LPS-challenge (100 μg/kg) showed a modestly exaggerated fever, attenuated adipsia and almost unimpaired locomotor activity compared to LPS-controls receiving vehicle (i.c.v.). The LPS-induced anorexia was not altered and AG490 did not have any effect on rats receiving PBS (i.p.). We did observe effects of AG490 on STAT3-signaling at 4 h, while AG490-mediated changes in brain activity of inflammatory transcription factors at 8 h were not significant. Increased NF-IL6 and suppressor of cytokines 3 mRNA-expression in AG490/LPS-treated rats were indicative of a compensative activation at 24 h. Moreover, a significant decrease in hypothalamic anti-inflammatory IL-10-expression and an increase in inflammatory microsomal prostaglandin E synthase (mPGES) mRNA-expression 8 h after LPS-injection was revealed in AG490 pre-treated animals compared to solvent-treated LPS-controls. In summary, we have shown a dissociation between the effects of central AG490 treatment on fever and components of sickness behavior, which appears to be related to reduced IL-10 and increased mPGES-expression in the brain. Thus, AG490 might have therapeutic potential to reduce sickness behavior.

Topics: Animals; Behavior, Animal; Body Temperature Regulation; Brain; Disease Models, Animal; Encephalitis; Enzyme Inhibitors; Gene Expression Regulation; Inflammation Mediators; Injections, Intraventricular; Janus Kinases; Lipopolysaccharides; Male; Nerve Tissue Proteins; Neurons; Rats; Rats, Wistar; RNA, Messenger; STAT Transcription Factors; Tyrphostins

Warm ischemia/reperfusion (I/R) is a common clinical problem during liver transplantation and liver resection. Warm ischemia also occurs during trauma and shock. However, there is still no safe and promising strategy for protecting the liver from I/R injury. Signal transducer and activator of transcription 3 (STAT3) is a major immediate response molecule for protecting cell survival. In this study, we first confirmed that a pharmacological STAT3 inhibitor, (E)-2-cyano-3-(3,4-dihydrophenyl)-N-(phenylmethyl)-2-propenamide (AG490), significantly reduced the survival of HepG2 cells, regardless of the serum condition. Furthermore, we created hepatocyte-specific STAT3-deficient mice with the cyclization recombination-locus of X-over P1 (Cre-LoxP) system to study the mechanisms of STAT3 in liver I/R injury. We found that the alanine aminotransferase level was significantly higher in hepatocyte-specific STAT3-deficient mice versus wild-type (WT) mice in a 70% liver I/R injury model. A histopathological examination showed that hepatocyte-specific STAT3-deficient mice suffered more severe damage than WT mice despite similar numbers of polymorphonuclear neutrophils in the 2 groups. These results indicate that endogenous STAT3 signaling in hepatocytes is required for protection of the liver in vitro and in vivo against warm I/R injury. In conclusion, endogenous STAT3 plays an important role in protecting the liver against I/R injury, and STAT3-targeting therapy could be a therapeutic approach to combating liver I/R injury.

Topics: Alanine Transaminase; Animals; Cell Proliferation; Cell Survival; Disease Models, Animal; Genotype; Hep G2 Cells; Hepatocytes; Humans; Ischemia; Liver; Liver Transplantation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Phosphorylation; Reperfusion Injury; STAT3 Transcription Factor; Tyrosine; Tyrphostins; Warm Ischemia

Cell therapies consist in transplanting healthy cells into a disabled tissue with the goal to repopulate it and restore its function at least partially. In muscular diseases, most of the time, myoblasts are chosen for their expansion capacity in culture. Nevertheless, cell transplantation has limitations, among them, death of the transplanted cells, during the days following the graft. One possibility to counteract this problem is to enhance the proliferation of the transplanted myoblasts before their fusion with the existing muscle fibers. AG490 is a specific inhibitor of janus tyrosine kinase 2 (JAK2). The hypothesis is to block myoblast differentiation with AG490, thus permitting their proliferation. The inhibition of myoblast fusion by AG490 was confirmed in this study by gene expression and with a myosin heavy chain staining (MyHC). Moreover, cell survival was estimated by flow cytometry. AG490 was found to protect myoblasts in vitro from apoptosis induced by H(2)O(2) or by preventing attachment of cells to their substrate. Finally, in an in vivo model of muscle regeneration, when AG490 was coinjected with the myoblasts their survival was increased by 45% at 5 days after their transplantation.

Topics: Animals; Cell Differentiation; Cell Survival; Cells, Cultured; Disease Models, Animal; Humans; Hydrogen Peroxide; Male; Mice; Muscle, Skeletal; Muscular Dystrophy, Duchenne; Myoblasts; Myosin Heavy Chains; Tyrphostins; Young Adult

Widespread death of implanted cells hampers the development of stem cell therapy for acute myocardial infarction (AMI). Our previous studies indicated that statins can protect implanted mesenchymal stem cells (MSCs) against the post-infarct microenvironment, thus increasing the therapeutic effect. However, the underlying mechanisms are unclear. The JAK-STAT pathway participates in regulation of stress responses of the myocardium to various insults. This study aimed to detect whether rosuvastatin (ROSU) facilitates the survival, engraftment, and differentiation of allogeneic bone marrow-derived MSCs in the post-infarct heart via the JAK-STAT signaling pathway.. Female Sprague-Dawley rats were randomized into 5 groups: AMI (control), ROSU gavage (group R), MSCs transplantation (group M), MSCs and ROSU (group M+R), or MSCs, ROSU and a JAK2 inhibitor AG-490 (group M+R+AG). MSCs from male rats were injected into the myocardium 1 week after AMI. Cardiac function and histology, as well as the expression of Y-chromosomal genes and JAK-STAT signaling proteins, were examined at 4 weeks after transplantation. Better functional recovery, increased survival and differentiation of MSCs occurred in group M+R. Furthermore, phosphorylation of JAK2 and STAT3 was higher in group M+R. The effects of ROSU, as well as of activated JAK-STAT proteins, could be attenuated by AG-490.. ROSU treatment improves the efficacy of stem cell transplantation in infarcted hearts by activation of the JAK2-STAT3 signaling pathway.

Topics: Animals; Cell Differentiation; Cell Survival; Cell Tracking; Cells, Cultured; Disease Models, Animal; Enzyme Activation; Female; Fluorobenzenes; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Janus Kinase 2; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Myocardial Contraction; Myocardial Infarction; Myocardium; Phosphorylation; Protein Kinase Inhibitors; Pyrimidines; Rats; Rats, Sprague-Dawley; Recovery of Function; Rosuvastatin Calcium; Signal Transduction; STAT3 Transcription Factor; Stroke Volume; Sulfonamides; Time Factors; Transplantation, Homologous; Tyrphostins; Ventricular Function, Left; Y Chromosome

Janus kinase (JAK) 2 is activated by ANG II in vitro and in vivo, and chronic blockade of JAK2 by the JAK2 inhibitor AG-490 has been shown recently to attenuate ANG II hypertension in mice. In this study, AG-490 was infused intravenously in chronically instrumented rats to determine if the blunted hypertension was linked to attenuation of the renal actions of ANG II. In male Sprague-Dawley rats, after a control period, ANG II at 10 ng·kg(-1)·min(-1) was infused intravenously with or without AG-490 at 10 ng·kg(-1)·min(-1) iv for 11 days. ANG II infusion (18 h/day) increased mean arterial pressure from 91 ± 3 to 168 ± 7 mmHg by day 11. That response was attenuated significantly in the ANG II + AG-490 group, with mean arterial pressure increasing only from 92 ± 5 to 127 ± 3 mmHg. ANG II infusion markedly decreased urinary sodium excretion, caused a rapid and sustained decrease in glomerular filtration rate to ∼60% of control, and increased renal JAK2 phosphorylation; all these responses were blocked by AG-490. However, chronic AG-490 treatment had no effect on the ability of a separate group of normal rats to maintain normal blood pressure when they were switched rapidly to a low-sodium diet, whereas blood pressure fell dramatically in losartan-treated rats on a low-sodium diet. These data suggest that activation of the JAK/STAT pathway is critical for the development of ANG II-induced hypertension by mediating its effects on renal sodium excretory capability, but the physiological control of blood pressure by ANG II with a low-salt diet does not require JAK2 activation.

Topics: Angiotensin II; Animals; Blood Pressure; Diet, Sodium-Restricted; Disease Models, Animal; Enzyme Inhibitors; Glomerular Filtration Rate; Hypertension; Infusions, Intravenous; Janus Kinase 2; Male; Phosphorylation; Rats; Rats, Sprague-Dawley; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

The cellular and molecular mechanisms that govern the response of the perinatal brain to injury remain largely unexplored. We investigated the role of white matter astrocytes in a rodent model of diffuse white matter injury produced by exposing neonatal mice to chronic hypoxia-a paradigm that mimics brain injury in premature infants. We demonstrate the absence of reactive gliosis in the immature white matter following chronic hypoxia, as determined by astrocyte proliferation index and glial fibrillary acidic protein levels. Instead, Nestin expression in astrocytes is transiently increased, and the glial-specific glutamate transporters glutamate-aspartate transporter (GLAST) and glutamate transporter 1 (GLT-1) are reduced. Finally, we demonstrate that Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling-which is important in both astrocyte development and response to injury-is reduced in the white matter following hypoxia, as well as in primary astrocytes exposed to hypoxia in vitro. Hypoxia and JAK/STAT inhibition reduce glutamate transporter expression in astrocytes, but unlike hypoxia JAK/STAT inhibition downregulates GLAST expression without affecting GLT-1, as demonstrated in vitro by treatment with JAK inhibitor I and in vivo by treatment with the JAK/STAT inhibitor AG490 [(E)-2-cyano-3-(3,4-dihydrophenyl)-N-(phenylmethyl)-2-propenamide]. Our findings (1) demonstrate specific changes in astrocyte function after perinatal hypoxia, which might contribute to the particular pathogenesis of perinatal white matter injury, (2) provide evidence that at least part of these changes result from a disturbance of the JAK/STAT pathway by hypoxia, and (3) identify JAK/STAT signaling as a potential therapeutic target to restore normal GLAST expression and uptake of glutamate after perinatal brain injury.

Topics: Age Factors; Amino Acid Transport System X-AG; Animals; Animals, Newborn; Aspartic Acid; Astrocytes; Bromodeoxyuridine; Cell Count; Cells, Cultured; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Gliosis; Green Fluorescent Proteins; Hypoxia; Intermediate Filament Proteins; Janus Kinases; Male; Mice; Mice, Transgenic; Nerve Tissue Proteins; Nestin; Signal Transduction; STAT Transcription Factors; Tritium; Tyrphostins

Cytokines are known to play an important role in the pathogenesis of lupus nephritis (LN) and the Jak/STAT (Janus kinase-signal transducer and activator of transcription factor) pathway is important in mediating signal transduction of cytokines. This study examined the pathogenic role of Jak/STAT signaling in LN. MRL/lpr mice were either treated with a selective Jak2 inhibitor tyrphostin AG490 or with vehicle alone from 12 weeks of age until being sacrificed at week 20. AG490 significantly inhibited the phosphorylation of Jak2 and STAT1 (p < 0.05). Compared with the vehicle-treated mice, AG490 treatment significantly reduced proteinuria, improved renal function and suppressed histological lesions of the kidneys and salivary glands (p < 0.05). AG490 treatment significantly inhibited the renal expression of monocyte chemotactic protein (MCP)-1, interferon (IFN)-gamma and class II MHC, which was accompanied by reduced renal infiltration of T cells and macrophages (p < 0.05). In addition, AG490 treatment resulted in a decrease in serum anti-double-stranded DNA (anti-dsDNA) antibody and attenuated the deposition of IgG and C3 in the kidneys (p < 0.05). This study demonstrated that Jak/STAT pathway is implicated in the progression of renal inflammation in MRL/lpr mice and targeting this pathway may provide a potential therapeutic approach for LN.

Topics: Animals; Antibodies, Antinuclear; Disease Models, Animal; Disease Progression; DNA; Enzyme Inhibitors; Female; Inflammation; Janus Kinase 2; Janus Kinases; Kidney; Lupus Nephritis; Mice; Mice, Inbred MRL lpr; Phosphorylation; Salivary Glands; Signal Transduction; STAT Transcription Factors; STAT1 Transcription Factor; Tyrphostins

Estrogen-mediated regulation of Th1, Th2 and Treg effector functions are well documented but, surprisingly, there is little information whether estrogen modulates IL-17, a powerful proinflammatory cytokine that plays a pivotal role in several inflammatory and autoimmune diseases. Therefore in the current study, we determined whether estrogen regulates the expression levels of IL-17 in WT C57BL/6 mice. By ELISA, ELISPOT and/or flow cytometric analyses, we found that estrogen upregulated the levels of not only IL-17, but also the IL-17-specific transcription factor retinoic acid-related orphan receptor gamma t (ROR gamma t), in activated splenocytes. IL-17 levels were further enhanced by exposure of activated splenocytes to IL-23, particularly in cells from estrogen-treated mice. Exposure of splenocytes to IL-27 or IFN-gamma at the time of activation markedly inhibited the levels of IL-17 and ROR gamma t. Interestingly, a delay of 24 h in exposure of activated splenocytes to IL-27 or IFN-gamma decreased IL-17 levels (albeit less profoundly) but not ROR gamma t. These findings imply that the suppressive effects of IL-27 and IFN-gamma are more effective prior to the differentiation and commitment of IL-17-secreting cells. Furthermore, inhibition of JAK-2 by AG490 suppressed IL-17 but not ROR gamma t expression, suggesting that other transcription factors are also critical in estrogen-mediated upregulation of IL-17.

Topics: Animals; Cells, Cultured; Disease Models, Animal; Estrogens; Female; Gene Expression Regulation; Humans; Interferon-gamma; Interleukin-17; Interleukin-23; Interleukins; Janus Kinase 2; Lupus Erythematosus, Systemic; Male; Mice; Mice, Inbred C57BL; Mice, Inbred NZB; Nuclear Receptor Subfamily 1, Group F, Member 3; T-Lymphocytes, Helper-Inducer; Tyrphostins

Topics: Animals; Cell Line, Tumor; Disease Models, Animal; Hepatocytes; Janus Kinase 2; Liver Diseases; Mice; Mice, Inbred C57BL; Protein Kinase Inhibitors; Reperfusion Injury; Signal Transduction; Tyrphostins

Ethanolamine is a biogenic amine found naturally in the body as part of membrane lipids and as a metabolite of the cardioprotective substances, sphingosine-1-phosphate (S1P) and anandamide. In the brain, ethanolamine, formed from the breakdown of anandamide protects against ischaemic apoptosis. However, the effects of ethanolamine in the heart are unknown. Signal transducer and activator of transcription 3 (STAT-3) is a critical prosurvival factor in ischaemia/reperfusion (I/R) injury. Therefore, we investigated whether ethanolamine protects the heart via activation of STAT-3. Isolated hearts from wildtype or cardiomyocyte specific STAT-3 knockout (K/O) mice were pre-treated with ethanolamine (Etn) (0.3 mmol/L) before I/R insult. In vivo rat hearts were subjected to 30 min ischaemia/2 h reperfusion in the presence or absence of 5 mg/kg S1P and/or the FAAH inhibitor, URB597. Infarct size was measured at the end of each protocol by triphenyltetrazolium chloride staining. Pre-treatment with ethanolamine decreased infarct size in isolated mouse or rat hearts subjected to I/R but this infarct sparing effect was lost in cardiomyocyte specific STAT-3 deficient mice. Pre-treatment with ethanolamine increased nuclear phosphorylated STAT-3 [control 0.75 ± 0.08 vs. Etn 1.50 ± 0.09 arbitrary units; P < 0.05]. Our findings suggest a novel cardioprotective role for ethanolamine against I/R injury via activation of STAT-3.

Topics: Amidohydrolases; Animals; Benzamides; Carbamates; Cardiovascular Agents; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Ethanolamine; Janus Kinases; Lysophospholipids; Male; Mice; Mice, Knockout; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Phosphorylation; Rats; Rats, Wistar; Sphingosine; STAT3 Transcription Factor; Tyrphostins

To investigate whether oxygen stresses experienced in retinopathy of prematurity (ROP) trigger signaling through reactive oxygen species (ROS) and whether the Janus kinase-signal transducer and activator of transcription (JAK/STAT) pathway lead to intravitreous neovascularization (IVNV) in an oxygen-induced retinopathy (OIR) rat model.. Newborn rat pups exposed to repeated fluctuations in oxygen and rescued in supplemental oxygen (28% O(2), 50/10 OIR+SO) were treated with apocynin, an NADPH oxidase and ROS inhibitor (10 mg/kg/d), AG490, a JAK2 inhibitor (5 mg/kg/d), or phosphate-buffered saline. Intraperitoneal injections were given from postnatal day (P)12 to P17 (apocynin), or from P3 to P17 (AG490). Outcomes were intravitreous neovascularization and avascular/total retinal areas, vascular endothelial growth factor, phosphorylated JAK2, and phosphorylated STAT3.. Apocynin significantly reduced phosphorylated STAT3 in 50/10 OIR+SO (P = 0.04), in association with previously reported inhibition of the IVNV area. Inhibition of JAK with AG490 significantly reduced phosphorylated JAK2 (P < 0.001), phosphorylated STAT3 (P = 0.002), and IVNV area (P = 0.033) in the 50/10 OIR+SO model compared with control.. Activation of NADPH oxidase from supplemental oxygen works through activated STAT3 to lead to IVNV. In addition, inhibition of the JAK/STAT pathway reduces IVNV. Further studies are needed to determine the effects and relationships of oxygen stresses on JAK/STAT and NAPDH oxidase signaling.

Topics: Acetophenones; Animals; Animals, Newborn; Blotting, Western; Disease Models, Animal; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Humans; Hyperoxia; Infant, Newborn; Janus Kinase 2; NADPH Oxidases; Neovascularization, Pathologic; Phosphorylation; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Retinal Vessels; Retinopathy of Prematurity; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; STAT3 Transcription Factor; Tyrphostins; Vascular Endothelial Growth Factor A; Vitreous Body

Cerebral ischemia and reperfusion increase superoxide anions (O(2)(*-)) in brain mitochondria. Manganese superoxide dismutase (Mn-SOD; SOD2), a primary mitochondrial antioxidant enzyme, scavenges superoxide radicals and its overexpression provides neuroprotection. However, the regulatory mechanism of Mn-SOD expression during cerebral ischemia and reperfusion is still unclear. In this study, we identified the signal transducer and activator of transcription 3 (STAT3) as a transcription factor of the mouse Mn-SOD gene, and elucidated the mechanism of O(2)(*-) overproduction after transient focal cerebral ischemia (tFCI). We found that Mn-SOD expression is significantly reduced by reperfusion in the cerebral ischemic brain. We also found that activated STAT3 is usually recruited into the mouse Mn-SOD promoter and upregulates transcription of the mouse Mn-SOD gene in the normal brain. However, at early postreperfusion periods after tFCI, STAT3 was rapidly downregulated, and its recruitment into the Mn-SOD promoter was completely blocked. In addition, transcriptional activity of the mouse Mn-SOD gene was significantly reduced by STAT3 inhibition in primary cortical neurons. Moreover, we found that STAT3 deactivated by reperfusion induces accumulation of O(2)(*-) in mitochondria. The loss of STAT3 activity induced neuronal cell death by reducing Mn-SOD expression. Using SOD2-/+ heterozygous knock-out mice, we found that Mn-SOD is a direct target of STAT3 in reperfusion-induced neuronal cell death. Our study demonstrates that STAT3 is a novel transcription factor of the mouse Mn-SOD gene and plays a crucial role as a neuroprotectant in regulating levels of reactive oxygen species in the mouse brain.

Topics: Animals; Brain; Brain Infarction; Brain Ischemia; Cells, Cultured; Chromatin Immunoprecipitation; Cytochromes c; Disease Models, Animal; Electrophoretic Mobility Shift Assay; Embryo, Mammalian; Glucose; Humans; Hypoxia; Interleukin-6; Male; Mice; Mice, Knockout; Neurons; Neuroprotective Agents; Reperfusion; RNA, Small Interfering; STAT3 Transcription Factor; Superoxide Dismutase; Time Factors; Transfection; Tyrphostins; Up-Regulation

Ischaemic postconditioning (IPostC) is a powerful protective phenomenon that activates prosurvival intrinsic signalling cascades to limit reperfusion injury. We propose that IPostC confers its infarct-sparing effect via activation of the newly described prosurvival Survivor Activating Factor Enhancement (SAFE) pathway, which involves the activation of the cytokine tumour necrosis factor alpha (TNFalpha) and signal transducer and activator of transcription-3 (STAT-3).. Isolated ischaemic/reperfused hearts from TNF knockout, TNF receptor-1 knockout, TNF receptor-2 knockout, cardiomyocyte-specific STAT-3-deficient mice or their respective wild-type, (TNF-WT) or (STAT-3-WT), were postconditioned by ischaemic episodes (IPostC) or with exogenous TNFalpha (0.5 microg/L) (TNF-PostC) at the onset of reperfusion. IPostC reduced infarct size (IS) in TNF-WT and TNFR1(-/-) hearts (by 33 and 27%, respectively, P < 0.05), whereas hearts from TNF(-/-) or TNFR2(-/-) failed to be postconditioned. TNF-PostC reduced IS by 37% (P < 0.05) in STAT-3-WT hearts but failed to protect cardiac-specific STAT-3(-/-) hearts. Administration of wortmannin, an inhibitor of PI-3 kinase/Akt, or PD98059, an inhibitor of extracellular regulated kinase 1/2 (Erk1/2), during the postconditioning stimulus did not abolish the infarct-sparing effect of TNF-PostC. AG490, an inhibitor of STAT-3, abrogated the protective effect of TNFalpha. Western blot analysis did not demonstrate the involvement of Akt or Erk1/2 in TNF-PostC, whereas STAT-3 phosphorylation was increased in both IPostC and TNF-PostC.. The protective effect of the SAFE pathway is shown in IPostC, with the activation of TNFalpha, its receptor type 2, and STAT-3. This signalling cascade is activated independently of the well-known Reperfusion Injury Salvage Kinases (RISK) pathway, which involves the kinases Akt and Erk1/2.

Topics: Androstadienes; Animals; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Flavonoids; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II; Signal Transduction; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha; Tyrphostins; Wortmannin

To investigate the neuroprotective effects and dose-response relation by combining JAK-STAT signal pathway inhibitor (AG490) with free radical scavenger dimethylthiourea (DMTU) in rats subjected to focal cerebral ischemia/reperfusion (I/R) injury.. In all rats, the middle cerebral artery occlusion (MCAO) was produced by occlusion of right internal carotid artery with a nylon monofilament. One hundred male Sprague-Dawley (SD) rats were divided into ten groups according to random digits table, 10 rats were in each group. The first experiment involved I/R model control, dimethyl sulfoxide (DMSO) control, normal saline (NS) control, AG490, DMTU and combination of AG490 and DMTU (A+D) groups. The second experiment involved model group and three experimental groups in which various doses of DMTU and AG490 were administered. The neurological behavior scores (NBS) were assessed at 24, 48 and 72 hours after reperfusion respectively in both experiments, and all the animals were then decapitated to determine the brain infarct volume after 72 hours.. The values of NBS in A+D group, AG490 group and DMTU group were higher than those in model group at 24, 48 and 72 hours after I/R, and their brain infarct volumes were obviously smaller than model group as well (all P<0.05). The brain infarct volume in A+D group was obviously smaller compared with AG490 and DMTU alone (all P<0.05). The values of NBS were higher and the brain infarct volumes were smaller in both high dose and medium dose combination groups than those in low dose combination and model groups respectively (all P<0.05). In addition, brain infarct volumes in high dose group were smaller than medium dose group (P<0.05), but there was no statistically significant difference between low dose and model groups.. The combined application of AG490 and DMTU produces a dose-dependent synergistic neuroprotective effect.

Topics: Animals; Brain; Brain Ischemia; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Free Radical Scavengers; Male; Neuroprotective Agents; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Signal Transduction; Thiourea; Tyrphostins

Mao is one component of various traditional herbal medicines. We examined the effects of Mao on an acute liver failure model treated with d-galactosamine (GalN) and lipopolysaccharide (LPS). The lethality of mice administrated Mao with GalN/LPS was significantly decreased compared with that in mice without Mao. Hepatic apoptosis and inflammatory cell infiltration were slight in Mao-treated mice. Serum alanine aminotransferase (ALT) and total bilirubin (T.Bil) activity, tumor necrosis factor alpha (TNF-alpha) levels and caspase 8, 9, and 3 activity in the liver were significantly lower in mice administrated Mao. But, Serum interleukin-6 (IL-6), IL-10 levels and signal transducers and activators of transcription 3 (STAT3) activity in the liver were significantly higher in mice administrated Mao. To investigate the effect of STAT3, we used AG490, which selectively inhibits the activation of Janus kinase (JAK) family tyrosine kinase and inhibits the constitutive activation of STAT3. There was significant aggravation in hepatic apoptosis treated with Mao and AG490 compared with Mao alone. In conclusions, Mao significantly suppressed hepatic apoptosis by inhibition of TNF-alpha production and caspase activity. Furthermore, it is also suggested that Mao, which activates STAT3 induced by IL-6, may be a useful therapeutic tool for fulminant hepatic failure.

Topics: Animals; Apoptosis; Caspases; Cytokines; Disease Models, Animal; Ephedra sinica; Galactosamine; Lipopolysaccharides; Liver; Liver Failure; Male; Mice; Mice, Inbred C57BL; Protein Kinase Inhibitors; STAT3 Transcription Factor; Tyrphostins

Heart transplantation is an accepted method of treatment for selected patients with end-stage heart disease. Making prolonged heart preservation safer will benefit patients awaiting heart transplantation. Granulocyte colony-stimulating factor (G-CSF) exhibited protective effects against myocardial ischemia-reperfusion injury mediated through the Janus kinase (Jak)/(signal transducer and activator of transcription (Stat) pathway. We examined whether pharmacologic preconditioning with G-CSF improves cardiac function after heart preservation.. Male rats were divided into four groups: group A, saline injection; group B, G-CSF, 10 microg/kg; group C, G-CSF, 100 microg/kg; and group D, G-CSF, 100 microg/kg plus AG490 (a selective Jak2 inhibitor), 1 mg/kg. The G-CSF and AG490 were given intravenously for 3 consecutive days. Four hours after the final treatment, isolated rat hearts underwent 12 hours of hypothermic (4 degrees C) preservation, followed by 60 minutes of normothermic reperfusion.. Stat3 phosphorylation was observed in the heart at 15 minutes after G-CSF treatment in group C, but this was attenuated by additional treatment with AG 490 in group D. Compared with group A, group C exhibited significant recovery of left ventricular pressure, maximum positive rate of left ventricular developed pressure (Max dP/dt), and coronary flow (p < 0.05, respectively), as well as lower creatine phosphokinase leakage during reperfusion (p < 0.05). Group B and group D did not show significant hemodynamic recovery during reperfusion. In group C, increased Bcl-xL and decreased Bax expressions as well as decreased terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling (TUNEL)-positive cardiomyocytes were observed after reperfusion. Immunohistochemical examination showed significantly increased capillary density before hypothermic preservation in group C, but not in other groups.. Pharmacologic preconditioning with G-CSF protected hearts from prolonged hypothermic ischemia-reperfusion injury.

Topics: Animals; Apoptosis; Blotting, Western; Disease Models, Animal; Granulocyte Colony-Stimulating Factor; Heart Function Tests; Heart Transplantation; Hemodynamics; Hypothermia, Induced; Immunohistochemistry; Infusions, Intravenous; Ischemic Preconditioning; Male; Myocardial Reperfusion Injury; Organ Preservation; Probability; Random Allocation; Rats; Rats, Sprague-Dawley; Reference Values; Sensitivity and Specificity; Tyrphostins

Erythropoietin (Epo) induces erythrocytosis by suppressing erythroid progenitor cell apoptosis through the Janus-activated kinase-signal transducers and activators of transcription (JAK-STAT) pathway. Since apoptosis contributes to cisplatin (CP)-induced nephrotoxicity and Epo receptors (EpoR) are expressed in the kidney, we examined the role of antiapoptosis in recombinant human erythropoietin (rHuEpo)-mediated renal protection. In human renal proximal tubular epithelial (RPTE) cells in culture, rHuEpo, but not inactive rHuEpo (I-rHuEpo), the receptor-binding sites of which are mutated, caused a significant reduction in CP-induced apoptosis at > or = 100 U/ml. rHuEpo, but not I-rHuEpo, increased STAT5 and Akt/PKB phosphorylation, demonstrating functional EpoR expression on RPTE cells. Furthermore, the JAK2 inhibitor tyrphostin AG-490 attenuated rHuEpo protection, suggesting a role of the JAK-STAT pathway in rHuEpo-mediated antiapoptosis. In rats, intravenous administration of 5,000 U/kg rHuEpo, but not an equivalent peptide mass of I-rHuEpo, before a single 5.5 mg/kg iv injection of CP, significantly increased hematocrit (Hct) and reduced the CP-induced increase in serum creatinine. Serum creatinine on day 4 was 3.4 +/- 0.3, 1.9 +/- 0.3, and 3.5 +/- 0.4 mg/dl in the CP, CP + rHuEpo, and CP + I-rHuEpo groups, respectively. Similarly, darbepoietin-alpha (DA), a hyperglycosylated analog of rHuEpo with prolonged in vivo activity when injected at 25 microg/kg iv before CP, significantly increased Hct and reduced serum creatinine. Renal clearance studies based on glomerular filtration rate and renal blood flow confirmed the significant renal protection by DA against CP. Tubular apoptosis and necrosis were significantly reduced in the kidneys of the CP + DA vs. the CP + saline group. Moreover, the equalization of Hct by venesection did not abrogate the DA-mediated renal protection. Administration of DA 48 h after CP injection also conferred significant renal protection. Thus our experiments confirm a role for erythropoiesis-stimulating proteins, including the new analog DA, in limiting CP-induced nephrotoxicity and suggest that antiapoptosis via the Epo-EpoR interaction is an important mechanism for renal protection.

Topics: Acute Kidney Injury; Animals; Antineoplastic Agents; Apoptosis; Cells, Cultured; Cisplatin; Darbepoetin alfa; Disease Models, Animal; Enzyme Inhibitors; Erythropoietin; Hematinics; Hematocrit; Humans; Janus Kinase 2; Kidney; Male; Necrosis; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Recombinant Proteins; STAT5 Transcription Factor; Tyrphostins

Pretreatment with atorvastatin (ATV) reduces infarct size (IS) and increases myocardial expression of phosphorylated endothelial nitric oxide synthase (p-eNOS), inducible NOS (iNOS), and cyclooxygenase-2 (COX2) in the rat. Inhibiting COX2 abolished the ATV-induced IS limitation without affecting p-eNOS and iNOS expression. We investigated 1) whether 3-day ATV pretreatment limits IS in eNOS(-/-) and iNOS(-/-) mice and 2) whether COX2 expression and/or activation by ATV is eNOS, iNOS, and/or NF-kappaB dependent. Male C57BL/6 wild-type (WT), University of North Carolina eNOS(-/-) and iNOS(-/-) mice received ATV (10 mg.kg(-1).day(-1); ATV(+)) or water alone (ATV(-)) for 3 days. Mice underwent 30 min of coronary artery occlusion and 4 h of reperfusion, or hearts were harvested and subjected to ELISA, immunoblotting, biotin switch, and electrophoretic mobility shift assay. As a result, ATV reduced IS only in the WT mice. ATV increased eNOS, p-eNOS, iNOS, and COX2 levels and activated NF-kappaB in WT mice. It also increased myocardial COX2 activity. In eNOS(-/-) mice, ATV increased COX2 expression but not COX2 activity or iNOS expression. NF-kappaB was not activated by ATV in the eNOS(-/-) mice. In the iNOS(-/-) mice, eNOS and p-eNOS levels were increased but not iNOS and COX2 levels; however, NF-kappaB was activated. In conclusion, both eNOS and iNOS are essential for the IS-limiting effect of ATV. The expression of COX2 by ATV is iNOS, but not eNOS or NF-kappaB, dependent. Activation of COX2 is dependent on iNOS.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Atorvastatin; Cyclooxygenase 2; Disease Models, Animal; Electrophoretic Mobility Shift Assay; Enzyme Activation; Enzyme-Linked Immunosorbent Assay; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Immunoblotting; Janus Kinases; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardium; NF-kappa B; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Peptides; Phosphorylation; Protein Kinase Inhibitors; Pyrroles; Time Factors; Tyrphostins; Up-Regulation

The Janus kinase (JAK) proteins are key regulators for transducing signals from the cell surface to the nucleus in response to cytokines to orchestrate the appropriate cellular response. Previous studies have demonstrated that JAK1 is activated in the basilar artery after subarachnoid hemorrhage (SAH), however it has not been investigated whether, and to what degree, JAK2 is induced by SAH and also the role of JAK2 in the pathogenesis of cerebral vasospasm following SAH remains unknown. Experiment 1 aimed to investigate the time-course of the JAK2 activation in the basilar artery after SAH. In Experiment 2, we chose the maximum time point of JAK2 activation and assessed the effect of AG490 (a specific JAK2 inhibitor) on regulation of cerebral vasospasm and endothelial apoptosis. All SAH animals were subjected to injection of autologous blood into cisterna magna twice on day 0 and day 2. As a result, the elevated expression of activated JAK2 was detected in the basilar artery after SAH and peaked on day 3. After AG490 intracisternal administration, the vasospasm was markedly aggravated and the apoptosis index of endothelial cells was also significantly increased in the basilar arteries. Anti-apoptotic genes such as bcl-2 and bcl-xL were down-regulated after the injections of AG490. Our results suggest that JAK2 is activated in the arterial wall after SAH, playing a beneficial role to vasospasm development, possibly through protecting endothelial cells and up-regulating anti-apoptotic genes.

Topics: Analysis of Variance; Animals; bcl-X Protein; Blood Vessels; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; In Situ Nick-End Labeling; Janus Kinase 2; Proto-Oncogene Proteins c-bcl-2; Rabbits; Subarachnoid Hemorrhage; Time Factors; Tyrphostins; Vasospasm, Intracranial

Children born small for gestational age (SGA) are at increased risk for short stature and type 2 diabetes mellitus as a result of growth hormone (GH) resistance and insulin resistance. The mechanisms of multiple hormone resistance remain unclear. This study was designed to investigate the relationship between GH resistance and insulin resistance in non-catch-up growth (NCU-SGA) rats, and how their signaling pathways are related based on their crosstalk on the insulin receptor substrate-1 phosphatidylinositol 3'-kinase (IRS-1-PI3K) pathway.. NCU-SGA rat model was developed by restricting prenatal food intake in pregnant dams. Activated levels of IRS-1 and Akt in liver protein extracts were compared between NCU-SGA and age- and sex-matched controls born appropriate for gestational age rats at baseline, after insulin stimulation, and after pretreatment with AG490 (GH-JAK2 pathway inhibitor) followed by insulin stimulation.. GH secretion was positively related to markedly increased insulin levels in NCU-SGA rats. There was no difference of IRS-1 phosphorylation in response to insulin between two groups, however, insulin-stimulated Akt phosphorylation was attenuated in NCU-SGA rats compared to appropriate for gestational age rats. Pretreatment with AG490 restored the Akt response to insulin demonstrated by significantly increased Akt phosphorylation.. GH plays a role in inducing insulin resistance via signaling crosstalk with insulin at the level of PI3K/Akt in NCU-SGA rats.

Topics: Adaptor Proteins, Signal Transducing; Animals; Animals, Newborn; Birth Weight; Diabetes Mellitus, Type 2; Disease Models, Animal; Enzyme Inhibitors; Female; Gestational Age; Growth Disorders; Growth Hormone; Humans; Infant, Newborn; Infant, Small for Gestational Age; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Male; Phosphatidylinositol 3-Kinases; Phosphorylation; Pregnancy; Proto-Oncogene Proteins c-akt; Signal Transduction; Tyrphostins

To evaluate the significance of the JAK-STAT pathway in insulin-induced cardioprotection from reperfusion injury.. In isolated perfused rat hearts subjected to insulin therapy (0.3 mU/ml) +/- AG490 (5 microM, JAK-STAT inhibitor), the phosphorylation state of STAT3 and Akt was determined after 15 min of reperfusion. Infarct size was measured after 120 min of reperfusion. Isolated cardiac myocytes from wild type (WT) and cardiac specific STAT3 deficient mice were treated with insulin at reoxygenation following simulated ischemia (SI, 26 h). Cell viability was measured after 120 min of reoxygenation following SI, whereas phosphorylation state of Akt was measured after 15 min of reoxygenation following SI.. Insulin given at reperfusion led to phosphorylation of STAT3 and Akt both of which were inhibited by AG490. AG490 also blocked the insulin-dependent decrease in infarct size, supporting a role for JAK-STAT in cardioprotection. In addition, insulin protection from SI was blocked in myocytes from the STAT3 deficient mice, or in WT mice treated with AG490. Furthermore, insulin failed to phosphorylate Akt in the STAT3 deficient cardiomyocytes.. Insulin-induced cardioprotection at reperfusion occurs through activation of STAT3. Inhibiting STAT3 by AG490, or STAT3 depletion in cardiac myocytes affects activation of Akt, suggesting close interaction between STAT3 and Akt in the cardioprotective signalling pathway activated by insulin treatment at reperfusion.

Topics: Animals; Cardiotonic Agents; Cell Death; Cell Survival; Disease Models, Animal; Enzyme Inhibitors; Insulin; Male; Mice; Mice, Mutant Strains; Myocardial Reperfusion Injury; Myocytes, Cardiac; Oxygen; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

This study investigated the role of JAK/STAT, an important pathway for cytokine signal transduction, in the progression of chronic glomerular diseases.. BALB/c mice received a single intravenous injection of adriamycin (10 mg/kg) were sacrificed 2, 4 and 6 weeks later. In the second study, treatment with the selective JAK2 inhibitor AG490 (15 mg/kg, q.d., i.p.) or vehicle was started 5 days after adriamycin injection. Functional and pathologic markers, inflammatory infiltration, expression of pro-inflammatory cytokines and phosphorylation of JAK2/STATs were assessed.. JAK/STAT signaling was activated in adriamycin nephropathy. Phosphorylation of JAK2, STAT1 and STAT3 was significantly inhibited by AG490 (p <0.01). Compared to the vehicle-treated controls, AG490 treatment did not reduce proteinuria 2 weeks after induction of the disease, but resulted in significant decrease in proteinuria and serum creatinine at week 6 (p <0.05). Glomerulosclerosis, tubulointerstitial lesions and renal alpha-SMA expression were also significantly suppressed by AG490 treatment at week 6 (p < 0.01). In addition, AG490 inhibited the expression of MCP-1 mRNA, accompanied by reduced interstitial infiltration of macrophages and T cells (p <0.05).. This study suggests that activation of JAK/STAT signaling is involved in the progression of glomerular diseases with proteinuric state.

Topics: Animals; Disease Models, Animal; Disease Progression; Enzyme Inhibitors; Janus Kinase 2; Kidney; Male; Mice; Mice, Inbred BALB C; Nephrotic Syndrome; Phosphorylation; Signal Transduction; STAT Transcription Factors; STAT1 Transcription Factor; STAT3 Transcription Factor; Tyrphostins

Intraocular pressure (IOP) elevation is an important cause of glaucoma. Animal models of ocular hypertension have been widely used to mimic glaucoma to investigate the mechanisms underlying retinal ganglion cell (RGC) death and search for possible cure. The aim of the present study was to examine the role of JAK/STAT pathway in RGC viability in normal condition or after acute IOP elevation. Retinal explants obtained from intact or IOP-elevated eyes were firstly used to examine the effect of the JAK/STAT pathway inhibitors, AG490 and Jak Inhibitor I, on RGC viability in vitro. The role of this signal pathway was further investigated and confirmed in vivo. AG490 and Jak Inhibitor I were applied into the left eye on days 3, 9, and 15 post 2-h IOP elevation at 110mmHg. Fluorescence dye Fluorogold was used to retrogradely label surviving RGCs. Because macrophage recruitment was seen in the IOP-elevated eyes after inhibition of this pathway, clodronate liposomes were used to remove phagocytic cells in the eye and examine the role of JAK/STAT pathway in RGC survival independent of macrophages. Activities and location of JAK/STAT pathway in the retina were examined using Western blotting and immunohistochemistry. We found that inhibition of JAK/STAT pathway did not affect RGC survival in the retinal explants derived from intact eye but caused RGC death in the retinal explants that were derived from IOP-elevated eye. Importantly, the detrimental effect of JAK/STAT pathway inhibition on RGC survival was also observed in vivo following acute IOP elevation, but not in intact eye. In addition, both in vitro and in vivo experiments confirmed a detrimental action of phagocytic cells following acute IOP elevation and the pathway inhibition. Compatible with what were observed in vivo, Western blotting and immunohistochemistry showed that JAK/STAT activities were not present in intact retina, but acute IOP elevation activated JAK/STAT pathway in the retina, in the regions of inner nuclear layer and ganglion cell layer, including RGCs. The IOP elevation-induced JAK/STAT activities were effectively abolished by intravitreal application of AG490. This study thus shows that (1) acute IOP elevation activates JAK/STAT pathway in RGCs, and (2) JAK/STAT pathway mediates RGC survival following IOP elevation but not under normal condition.

Topics: Acute Disease; Animals; Cell Survival; Disease Models, Animal; Enzyme Inhibitors; Eye Proteins; Glaucoma; Janus Kinases; Macrophages; Rats; Rats, Sprague-Dawley; Retinal Ganglion Cells; Signal Transduction; STAT Transcription Factors; Tissue Culture Techniques; Tyrphostins

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathway is one of the most important in transducing signals from the cell surface to the nucleus in response to cytokines. In the present study, we investigated chronological alteration and cellular location of JAK1, STAT3, phosphorylated (p)-Tyr1022/1023-JAK1, p-Tyr705-STAT3, and interleukin-6 (IL-6) following spinal cord injury (SCI) in mice. Western blot analysis showed JAK1 to be significantly phosphorylated at Tyr1022/1023 from 6 h after SCI, peaking at 12 h and gradually decreasing thereafter, accompanied by phosphorylation of STAT3 at Tyr705 with a similar time course. ELISA analysis showed the concentration of IL-6 in injured spinal cord to also significantly increase from 3 h after SCI, peaking at 12 h, then gradually decreasing. Immunohistochemistry revealed p-Tyr1022/1023-JAK1, p-Tyr705-STAT3, and IL-6 to be mainly expressed in neurons of the anterior horns at 12 h after SCI. Pretreatment with a JAK inhibitor, AG-490, suppressed phosphorylation of JAK1 and STAT3 at 12 h after SCI, reducing recovery of motor functions. These findings suggest that SCI at the acute stage produces IL-6 mainly in neurons of the injured spinal cord, which activates the JAK/STAT pathway, and that this pathway may be involved with neuronal response to SCI.

Topics: Animals; Dimethyl Sulfoxide; Disease Models, Animal; Enzyme Inhibitors; Female; Janus Kinase 1; Mice; Mice, Inbred C57BL; Neurons; Protein-Tyrosine Kinases; Signal Transduction; Spinal Cord Injuries; STAT3 Transcription Factor; Tyrphostins

We examined the role of Jak2 kinase phosphorylation in the development of pressure overload hypertrophy in mice subjected to transverse aortic constriction (TAC) and treated with tyrphostin AG490, a pharmacological inhibitor of Jak2.. Control mice (sham), subjected to TAC for 15 days (TAC) or to TAC and treated with 48 microg/kg/day i.p. of tyrphostin AG490 (TAC+AG490) were evaluated for morphological, physiological, and molecular changes associated with pressure overload hypertrophy.. Mice subjected to TAC alone developed concentric hypertrophy that accompanied activation of the components of the Jak/STAT signaling pathway manifested by an increase in phosphorylation of Jak2 and STAT3. We also observed increased phosphorylation of MAPK p44/p42, p38 MAPK and JNK in the TAC group, as well as, an increase in expression of MKP-1 phosphatase which negatively regulates MAPK kinases. Treatment of aortic constricted mice with tyrphostin AG490 failed to develop hypertrophy and showed a marked reduction in phosphorylation of Jak2 and STAT3. There was, however, in TAC and AG490 treated mice, a notable increase in the phosphorylation state of the MAPK p44/42, whereas MKP-1 phosphatase was downregulated.. These findings suggest that Jak2 kinase plays an important role in left ventricular remodeling during pressure overload hypertrophy. Pharmacological inhibition of Jak2 kinase during pressure overload blocks the development of concentric hypertrophy.

Topics: Actins; Animals; Aorta, Thoracic; Atrial Natriuretic Factor; Blood Pressure; Cardiomegaly; Disease Models, Animal; Echocardiography; Heart Ventricles; Janus Kinase 2; Ligation; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Phosphorylation; Protein Kinase Inhibitors; RNA, Messenger; STAT3 Transcription Factor; Tyrphostins; Ventricular Function, Left; Ventricular Myosins; Ventricular Remodeling

Cerulein pancreatitis is similar to human edematous pancreatitis with dysregulation of the digestive enzyme production and cytoplasmic vacuolization, the death of acinar cells, edema formation, and an infiltration of inflammatory cells into the pancreas. Cytokines are up-regulated in pancreatic acinar cells stimulated with cerulein. In various cells and tissues, Janus kinase (Jak)/signal transducer and activator of transcription (Stat) pathway mediates inflammatory process. In the present study, we investigated whether the activation of Jak/Stat signaling mediates IL-1beta expression in pancreatic acinar AR42J cells stimulated with cerulein in vitro as well as the rats with cerulein pancreatitis in vivo using AG490, the Jak2 inhibitor. Activation of Jak2 and Stat3 were monitored by Western blot analysis for phosphorylated Jak2 and phosphorylated Stat3. mRNA expression and protein level of IL-1beta were determined by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbant assay (ELISA). Histological examination of pancreatic tissues were performed and serum IL-1beta levels of the rats were determined by ELISA. As a result, cerulein induced the activation of Jak2 and Stat3 as well as IL-1beta expression, which was inhibited by the treatment of AG490 in AR42J cells. In cerulein pancreatitis of the rats, edematous and inflammatory changes of the pancreas and increased serum levels of IL-1beta were suppressed by AG490 treatment. In conclusion, Jak2/Stat3 pathway may be the underlying mechanism in the pathogenesis of pancreatitis by inducing cytokines such as IL-1beta.

Topics: Animals; Cells, Cultured; Ceruletide; Disease Models, Animal; Drug Therapy, Combination; Enzyme Inhibitors; Gene Expression; Interleukin-1beta; Janus Kinase 2; Male; Pancreas; Pancreatitis; Phosphorylation; Rats; Rats, Sprague-Dawley; RNA, Messenger; STAT3 Transcription Factor; Tyrphostins

Tyrphostin AG490 (AG490) potently and selectively inhibits gammac/Janus kinase 3-dependent signaling pathways, including downstream Stat5a/b activation and subsequent T cell proliferation by alloantigen stimulation. We evaluated the effects of AG490 on acute rat lung allograft rejection.. A 7-day course of an intraperitoneal (IP) injection with 10 mg/kg, 15 mg/kg, or 20 mg/kg AG490 was administered to inhibit the rejection of orthotopically transplanted Brown Norway (RT1n) rat lung allografts in Fischer 344 (RT1(1vl)) rat recipients. The progression of allograft rejection was evaluated by X-ray with a semi-quantitative scoring system and was evaluated histologically with a semi-quantitative rejection scoring system for acute lung allograft rejection. Moreover, to determine whether AG490 regulates CD4+ T cell differentiation during acute rejection, flow cytometry was used to investigate Th1 (interferon-gamma) and Th2 (interleukin [IL]-4, IL-10) intracellular cytokine profiles and the CD4+CD25+ T cell population in recipient splenocytes.. Results of radiology and histology confirmed that treatment with AG490 significantly suppressed acute lung allograft rejection. Furthermore, the splenocytes of the AG490-treated recipients had significantly lower production of interferon-gamma and relatively higher production of IL-10, implying that a Th2 shift was induced by AG490. In addition, AG490-treated recipients had a significantly increased population of CD4+CD25+ T cells in their splenocytes on Day 6 after transplantation.. These findings suggest that treatment with AG490 prevents acute lung allograft rejection in rats. The effects of AG490 may contribute to development of CD4+CD25+ T cells and a Th2 shift of CD4+ T cells.

Topics: Acute Disease; Animals; CD4 Antigens; Cell Differentiation; Cell Proliferation; Disease Models, Animal; Disease Progression; Graft Rejection; Injections, Intraperitoneal; Interferon-gamma; Interleukin-10; Interleukin-4; Janus Kinase 3; Lung Transplantation; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Rats; Rats, Inbred BN; Rats, Inbred F344; Receptors, Interleukin-2; Signal Transduction; Spleen; STAT5 Transcription Factor; T-Lymphocytes; Tyrphostins

To investigate the role of Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway in mediating mRNA expression of high mobility group box 1 protein (HMGB1) in the liver in septic rats.. Using a sepsis model of cecal ligation and puncture (CLP), 98 male Wistar rats were randomly divided into normal control group (n=10), CLP group (n=40), AG490 treatment group (n=24), and Rapamycin (RPM) treatment group (n=24). At serial time points animals in each group were sacrificed, and blood as well as hepatic tissue samples were harvested to determine HMGB1 mRNA expression and serum aspartate aminotransferase (AST) as well as alanine aminotransferase (ALT) contents.. Compared with normal controls, HMGB1 mRNA levels were significantly increased in the liver during 6-48 hours after CLP (P<0.01), and serum AST and ALT contents were significantly elevated at different time points respectively (P<0.05 or P<0.01). Treatment with AG490 and RPM could markedly inhibit HMGB1 mRNA expression in the liver at 24 hours, 48 hours, 6 hours and 24 hours after CLP, respectively. In addition, compared to CLP group, serum AST and ALT contents in both treatment groups could be markedly reduced at various intervals after CLP (P<0.05 or P<0.01).. These data suggest that the activation of JAK/STAT pathway might be involved in mediating up-regulation of HMGB1 mRNA expression in the liver in CLP-induced sepsis. Treatment with inhibitors of JAK/STAT pathway could markedly down-regulate HMGB1 mRNA expression and attenuate acute liver injury associated with sepsis.

Topics: Alanine Transaminase; Animals; Anti-Bacterial Agents; Aspartic Acid; Disease Models, Animal; DNA-Binding Proteins; Enzyme Inhibitors; Gene Expression; HMGB1 Protein; Liver; Male; Protein-Tyrosine Kinases; Random Allocation; Rats; Rats, Wistar; RNA, Messenger; Sepsis; Signal Transduction; Sirolimus; Trans-Activators; Transcription, Genetic; Transcriptional Activation; Tyrphostins

Examination of signaling pathways used by HTLV-1-infected rabbit cell lines revealed differences between one, RH/K30, that mediates asymptomatic infection and another, RH/K34, that causes lethal experimental leukemia. Both lines are IL-2 independent; RH/K30 produces IL-4 while RH/K34 produces IL-10. Examination of the Jak/STAT (Janus kinase/signal transducer and activator of transcription) activation of the lines revealed constitutive phosphorylation of Jak1 in both STAT6 phosphorylation, not previously reported for HTLV-1 cells, was observed in RH/K30; STAT1 and STAT3 were phosphorylated in RH/K34. Treatment with cytokines altered the activation of the STAT proteins: IL-2 induced STAT5 phosphorylation in both lines. Supernatant from RH/K34 or IL-10 induced STAT3 phosphorylation in RH/K30 cells. Supernatant from RH/K30 or IL-4 induced STAT6 phosphorylation in RH/K34 cells, which could be reversed with a Jak kinase inhibitor--AG-490.

Topics: Animals; Cell Line; Disease Models, Animal; DNA-Binding Proteins; Enzyme Inhibitors; Gene Expression; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Interleukin-10; Interleukin-2; Interleukin-4; Janus Kinase 1; Milk Proteins; Phosphorylation; Protein-Tyrosine Kinases; Rabbits; Signal Transduction; STAT1 Transcription Factor; STAT3 Transcription Factor; STAT5 Transcription Factor; STAT6 Transcription Factor; Trans-Activators; Tumor Cells, Cultured; Tyrphostins