cyclin-d1 and Infarction--Middle-Cerebral-Artery

Remote ischemic pre-conditioning (RIPC) protects against ischemia/reperfusion (I/R) injury. However, the mechanisms underlying this protection remain unclear. In the present study, we investigated the role of Janus-activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway and cell cycle arrest, and their relationship with neuronal apoptosis following RIPC.. A rat cerebral I/R injury model was induced by middle cerebral artery occlusion (MCAO), and AG490 was used to investigate the mechanisms of RIPC. p-JAK2-, p-STAT3-, cyclin D1-, and cyclin-dependent kinase 6 (CDK6) expression was assessed by Western blotting and immunofluorescence staining.. RIPC reduced the infarct volume, improved neurological function, and increased neuronal survival. Furthermore, p-JAK2 and p-STAT3 were detected during the initial phase of reperfusion; the expression levels were significantly increased at 3 and 24 h after reperfusion and were suppressed by RIPC. Additionally, the MCAO-induced upregulation of the cell cycle regulators cyclin D1 and CDK6 was ameliorated by RIPC. Meanwhile, cyclin D1 and CDK6 were colocalized with p-STAT3 in the ischemic brain.. RIPC ameliorates the induction of the JAK2/STAT3 pathway and cell cycle regulators cyclin D1 and CDK6 by MCAO, and this net inhibition of cell cycle re-entry by RIPC is associated with downregulation of STAT3 phosphorylation.

Topics: Animals; Brain Ischemia; Cell Cycle; Cyclin D1; Hindlimb; Infarction, Middle Cerebral Artery; Ischemic Preconditioning; Janus Kinase 2; Rats; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor

10-O-(N,N-dimethylaminoethyl)-ginkgolide B methanesulfonate (XQ-1H), a new derivative of ginkgolide B, has drawn great attention for its potent bioactivities against ischemia-induced injury. The purpose of this study was to further investigate the effect of XQ-1H against acute ischemic stroke by inducing middle cerebral artery occlusion/reperfusion (MCAO/R) injuries in mice.. Treatment of XQ-1H (78 or 39 mg/kg, i.g., bid) 2 h after MCAO improved motor skills and ameliorated the severity of brain infarction and apoptosis seen in the mice by diminishing pathological changes and the activation of a pro-apoptotic protein Cleaved-Caspase-3, which in turn induced anti-apoptotic Bcl-xL. Through introducing Wnt/β-catenin signaling inhibitor XAV-939, XQ-1H was proven to intensively promoted neurogenesis in the peri-infarct cortex, subventricular area (SVZ) and the dentate gyrus (DG) subgranular area (SGZ) in a Wnt signal dependent way by compromising the activation of GSK3β, which in turn upregulated Wnt1, β-catenin, Neuro D1 and Cyclin D1, most possibly through the activation of PI3K/Akt signaling via the upregulation of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).. We conclude that XQ-1H preserved the motor functions, limited apoptosis, and concomitantly promoted neurogenesis-related protein expression by Wnt signaling-dependently compromising GSK3β/Caspase-3 activity and enhancing the expression of Wnt1/β-catenin/Neuro D1/Cyclin D1 and Bcl-xL.. This research may benefit the development of stroke therapeutics targeting neurogenesis through Wnt upregulation by XQ-1H.

Topics: Animals; Apoptosis; bcl-X Protein; beta Catenin; Brain; Brain Ischemia; Caspase 3; Cyclin D1; Ginkgolides; Glycogen Synthase Kinase 3 beta; Heterocyclic Compounds, 3-Ring; Infarction, Middle Cerebral Artery; Lactones; Male; Mice; Nerve Growth Factor; Neurogenesis; Recovery of Function; Stroke; Up-Regulation; Wnt Signaling Pathway

Granulocyte-colony stimulating factor (G-CSF) is an endogenous growth factor that exhibits a diverse range of neuroprotective mechanisms against a variety of neurological disorders including ischemic stroke. We investigated the anti-apoptotic mechanisms of G-CSF against endoplasmic reticulum (ER) stress induced apoptosis. Sprague-Dawley rats were subjected to transient occlusion of the middle cerebral artery (MCAO) for 90 min. Rats were injected with G-CSF (n = 15; 50 μg/kg body weight s.c.) for 4 days, starting 24 h post-MCAO and brains were harvested after 4 days reperfusion (n = 16). Key proteins in ER stress apoptosis were analyzed by immunoblotting. G-CSF reduced infarct volume to 53% and improved neurological deficits. G-CSF treatment significantly (P < .05) attenuated the expression of proteins involved in ER stress apoptosis pathway; ATF4, ATF6, p-p38MAPK, pJNK and CHOP. G-CSF treatment also re-established ER homeostasis evident by the reduction of the intraluminal ER stress sensor, GRP78 as well as reducing the overall cellular stress level protein, HSP27. G-CSF also up-regulated anti-apoptotic proteins pAKT and Bcl-2 while down-regulated the pro-apoptotic protein Bax. G-CSF exerts neuroprotection from cerebral ischemia through the preservation of the ER, resulting in the attenuation of pro-apoptotic proteins and the potentiation of anti-apoptotic proteins.

Topics: Activating Transcription Factor 6; Analysis of Variance; Animals; Apoptosis; bcl-2-Associated X Protein; Brain Infarction; Cyclin D1; Disease Models, Animal; Endoplasmic Reticulum Stress; Granulocyte Colony-Stimulating Factor; Infarction, Middle Cerebral Artery; Male; Neurologic Examination; Neuroprotective Agents; Phosphopyruvate Hydratase; Rats; Rats, Sprague-Dawley; Receptors, Granulocyte Colony-Stimulating Factor; Signal Transduction

Physical exercise is beneficial for the functional recovery of neurons after stroke. It has been suggested that exercise regulates proliferation and differentiation of endogenous neural stem cells (NSCs); however, the underlying molecular mechanisms are still largely unknown. In the present study, the aim was to investigate whether physical exercise activates the extracellular signal‑regulated kinase (ERK) signaling pathway to promote proliferation and differentiation of NSCs in rats with cerebral infarction, thereby improving neurological function. Following middle cerebral artery occlusion, rats underwent physical exercise and neurological behavior was analyzed at various time points. Immunofluorescence staining was performed to detect proliferation and differentiation of NSCs, and western blotting was used to analyze cyclin‑dependent kinase 4 (CDK4), Cyclin D1, retinoblastoma protein (p‑Rb), P‑16, phosphorylated (p)‑ERK1/2 and c‑Fos expression. The results indicated that physical exercise promoted proliferation and differentiation of NSCs, and led to improved neural function. In addition, the expression levels of CDK4, Cyclin D1, p‑Rb, p‑ERK1/2 and c‑Fos were upregulated, whereas the expression of P‑16 was downregulated following exercise. U0126, an inhibitor of ERK signaling, reversed the beneficial effects of exercise. Therefore, it may be hypothesized that physical exercise enhances proliferation and differentiation of endogenous NSCs in the hippocampus of rats with cerebral infarction via the ERK signaling pathway.

Topics: Animals; Butadienes; Cell Differentiation; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase 4; Gene Expression Regulation; Hippocampus; Infarction, Middle Cerebral Artery; Male; Middle Cerebral Artery; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neural Stem Cells; Nitriles; Physical Conditioning, Animal; Proto-Oncogene Proteins c-fos; Rats; Rats, Sprague-Dawley; Retinoblastoma Protein; Signal Transduction

The central objective was to identify the role of the PI3K-Akt activation pathway on the neuroprotection of δ-opioid receptor agonist (DADLE) against cerebral ischemia-reperfusion (I/R) injury in a rat model. Fifty-five male Sprague-Dawley (SD) rats were included to establish a middle cerebral artery occlusion (MCAO) model which were then divided into the sham, MCAO, LY294002 (MCAO+DADLE+LY294002 [inhibitor of PI3K-Akt pathway]), DADLE (MCAO+DADLE) and DMSO (MCAO+DADLE+DMSO [dimethyl sulphoxide]) groups. The cerebral infarction (CI) volume and nerve cell apoptosis was determined using TTC and TUNEL staining. Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting and immunohistochemistry staining were applied for the expressions of Bad, Bax, Bcl-2 and cleaved caspase-3. The MCAO group showed higher CI volume, nerve cell apoptosis and cleaved caspase-3 expressions than the DADLE and DMSO groups, which were also higher in the LY294002 group than the DADLE group. Compared with the MCAO group, the mRNA and protein expressions of PI3K and Bcl-2, and the protein expressions of p-Akt and p-Bad were elevated, while the mRNA and protein expressions of Bax were decreased in the DADLE and DMSO groups. Decreased mRNA and protein expressions of PI3K and Bcl-2, reduced protein expressions of p-Akt and p-Bad and elevated mRNA and protein expressions of Bax exhibited in the LY294002 group than the DADLE group. These results indicate that activation of PI3K-Akt pathway promotes the neuroprotection of DADLE against cerebral I/R injury in a rat model by decreasing nerve cells apoptosis.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Brain Ischemia; Caspase 3; Cyclin D1; Infarction, Middle Cerebral Artery; Male; Neuroprotection; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Reperfusion Injury; RNA, Messenger; Signal Transduction

Transplantation of bone marrow stromal cells (BMSCs) improves animal neurological functional recovery after stroke. But the mechanism remains unclear. As cell cycle machinery plays an important role in stroke, we investigated the dynamic changes of cell cycle elements in a rat model of middle cerebral artery occlusion. We found the cell cycle markers, cdk4 along with its activator cyclin D1, and proliferating cell nuclear antigen (PCNA), increased after brain ischemia-reperfusion. Phosphorylation of the retinoblastoma protein (pRb, on ser-795), the cyclin D/cdk4 complex mutual target, was upregulated accordingly. However, intravenously administrated BMSCs facilitated cyclin D1, cdk4, and PCNA decrease in the ischemic cortex. Meanwhile, phospho-pRb (ser-795) was completely inhibited. On the contrary, endogenous cdk inhibitor p27 reduced before but enhanced after BMSCs treatment. These findings suggested BMSCs might modulate cell cycle progression in injured brain via downregulation of the cyclin D1/cdk4/pRb pathway as well as upregulation of p27 level. These results provide another way by which BMSCs may contribute to the recovery from stroke.

Topics: Animals; Bone Marrow Transplantation; Brain Ischemia; Cell Cycle; Cerebral Cortex; Cyclin D1; Cyclin-Dependent Kinase 4; Disease Models, Animal; Infarction, Middle Cerebral Artery; Male; Phosphorylation; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Retinoblastoma Protein; Signal Transduction; Stroke; Stromal Cells

Cyclooxygenase-2 (COX-2) activity has been implicated in the pathogenesis of neuronal cell death in ischemia and other diseases, but the mechanism by which COX-2 exacerbates cell death is unknown. COX-2 activity is known to induce expression of cyclin D1 in neoplastic cells, and cyclin D1 expression can induce cell death in postmitotic neurons. In the present study, the role of COX-2 and cyclin D1 in neuronal cell death induced by anoxia and ischemia was examined. Treatment with the COX-2 specific inhibitor (NS 398 25 microM) and cyclin D1 inhibitor (flavopiridol 1 microM) increased neuronal survival and inhibited DNA fragmentation after anoxia. NS-398 suppressed anoxia-induced expression of cyclin D1. Flavopiridol inhibited the anoxia-induced increased expression of cyclin D1, but had no effect on COX-2 expression. Treatment with the selective COX-2 inhibitor, SC58125, had no affect on COX-2 expression but partially suppressed cyclin D1 expression in the cortex following middle cerebral artery occlusion in vivo. These results show that COX-2 activity is required for cyclin D1 expression after ischemia in vivo and anoxia in vitro. These data provide support for the hypothesis that cyclin D1 expression is an important mechanism by which COX-2 activity exacerbates ischemic neuronal death.

Topics: Animals; Cell Survival; Cells, Cultured; Cyclin D1; Cyclooxygenase 2; Disease Models, Animal; DNA Fragmentation; Dose-Response Relationship, Drug; Enzyme Inhibitors; Flavonoids; Hypoxia-Ischemia, Brain; Infarction, Middle Cerebral Artery; Neurons; Neuroprotective Agents; Nitrobenzenes; Piperidines; Prostaglandin-Endoperoxide Synthases; Pyrazoles; Rats; Rats, Sprague-Dawley; Sulfonamides