ex-527 and Sepsis

Sepsis-induced brain injury is frequently encountered in critically ill patients with severe systemic infection. Butein (3,4,2',4'-tetrahydroxychalcone) has been demonstrated as the neuro-protective agent via reducing inflammation and oxidative stress on neurons. Moreover, activation of silent information regulator 1 (SIRT1) inhibits apoptosis, oxidation and inflammation thus alleviating sepsis-induced multiorgan injuries. In present study, we show that butein administrated intraperitoneally (10 mg/kg) saved mice from sepsis-induced lethality by increasing 7-day survival rate after cecal ligation and puncture (CLP) surgery. Additionally, butein treatment enhanced SIRT1 signaling thus decreasing the Ac-NF-κB, Ac-FOXO1 and Ac-p53 levels, thus attenuating the brain injury of mice after CLP surgery by decreasing cerebral edema, maintaining the blood-brain barrier integrity, inhibiting neuronal apoptosis, and decreasing pro-inflammatory cytokines production (IL-6, TNF-α and IL-1β) and oxidative stress (downregulation of MDA, and upregulation of SOD and CAT) in both serum and cerebral cortex tissues. Moreover, butein treatment attenuated LPS induced neurological function loss. However, all above mentioned neuro-protective actions of butein were partially inhibited by EX527 co-treatment, one standard SIRT1 inhibitor. Collectively, butein attenuates sepsis-induced brain injury through alleviation of cerebral inflammation, oxidative stress and apoptosis by SIRT1 signaling activation.

Topics: Animals; Apoptosis; Blood-Brain Barrier; Carbazoles; Chalcones; Disease Models, Animal; Humans; Inflammation; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Oxidative Stress; Sepsis; Sepsis-Associated Encephalopathy; Signal Transduction; Sirtuin 1; Treatment Outcome

Sepsis, a life-threatening disease with high morbidity and mortality in critically ill patients, usually leads to serious complications including liver damage and dysregulated metabolic homoeostasis. The aim of this study was to evaluate the therapeutic potential of melatonin in rats with caecal ligation and puncture (CLP)-induced sepsis, which mimics critical infections in humans and explore the underlying molecular mechanisms. Male Sprague-Dawley rats received CLP surgery under anaesthesia to induce polymicrobial sepsis. Melatonin (20 mg/kg) was intraperitoneally (i.p.) injected every 12 h for 7 days after CLP, with or without intraperitoneal injection of the SIRT1 inhibitor EX527 (5 mg/kg). Markers of glucose metabolism, inflammation, liver function and associated signaling pathway were measured. Septic rats exhibited marked inhibition of the hepatic SIRT1/STAT3 pathway, along with increased blood glucose levels and hepatic gluconeogenesis. Melatonin administration efficiently attenuated liver dysfunction and glucose metabolism disorders by promoting hepatic SIRT1 expression and STAT3 phosphorylation. Furthermore, inhibition of SIRT1 by EX527 significantly diminished the protective effects of melatonin on sepsis induced liver injury, hyperglycaemia and STAT3 inactivation. These results emphasize that melatonin is a potential therapeutic agent for sepsis-associated liver injury and glucose metabolism disorders, possibly acting by targeting SIRT1-mediated STAT3 activation in the liver.

Topics: Acetylation; Animals; Carbazoles; Cecum; Cytokines; Enzyme Activation; Gluconeogenesis; Inflammation Mediators; Ligation; Liver; Male; Melatonin; Phosphorylation; Protective Agents; Proto-Oncogene Proteins c-akt; Punctures; Rats, Sprague-Dawley; Reactive Oxygen Species; Sepsis; Signal Transduction; Sirtuin 1; STAT3 Transcription Factor

MicroRNA-199a (miR-199a) is a novel gene regulator with an important role in inflammation and lung injury. However, its role in the pathogenesis of sepsis-induced acute respiratory distress syndrome (ARDS) is currently unknown. Our study explored the role of miR-199a in sepsis-induced ARDS and its mechanism of action. First, we found that LPS could upregulate miR-199a in alveolar macrophages. Downregulation of miR-199a inhibited the upregulation of inflammatory cytokines in alveolar macrophages and induced the remission of histopathologic changes, the reduction of proinflammatory cytokines, and the upregulation of apoptosis protein expression in an ARDS lung, showing a protective role for miR-199a. We further identified sirtuin 1 (SIRT1) as a direct target of miR-199a in alveolar macrophages, and the expression of SIRT1 was negatively correlated with the level of miR-199a. The protective role of miR-199a downregulation in LPS-stimulated alveolar macrophages and sepsis-induced ARDS could be attenuated by SIRT1 inhibitor. Taken together, these results indicate that downregulation of miR-199a might protect lung tissue against sepsis-induced ARDS by upregulation of SIRT1 through the suppression of excessive inflammatory responses and the inhibition of cellular apoptosis in lung tissue, suggesting its potential therapeutic effects on sepsis-induced ARDS.

Topics: 3' Untranslated Regions; Acute Lung Injury; Animals; Antagomirs; Apoptosis; Binding Sites; Burns; Carbazoles; Cytokines; Disease Models, Animal; Down-Regulation; Gene Expression Regulation, Enzymologic; Histone Deacetylase Inhibitors; Inflammation Mediators; Lung; Macrophages, Alveolar; Male; Mice, Inbred C57BL; MicroRNAs; Pseudomonas aeruginosa; Pseudomonas Infections; Respiratory Distress Syndrome; Sepsis; Signal Transduction; Sirtuin 1

Sepsis often results in damage to multiple organ systems, possibly due to severe mitochondrial dysfunction. Two members of the sirtuin family, SIRT1 and SIRT3, have been implicated in the reversal of mitochondrial damage. The aim of this study was to determine the role of SIRT1/3 in acute kidney injury (AKI) following sepsis in a septic rat model. After drug pretreatment and cecal ligation and puncture (CLP) model reproduction in the rats, we performed survival time evaluation and kidney tissue extraction and renal tubular epithelial cell (RTEC) isolation. We observed reduced SIRT1/3 activity, elevated acetylated SOD2 (ac-SOD2) levels and oxidative stress, and damaged mitochondria in RTECs following sepsis. Treatment with resveratrol (RSV), a chemical SIRT1 activator, effectively restored SIRT1/3 activity, reduced acetylated SOD2 levels, ameliorated oxidative stress and mitochondrial function of RTECs, and prolonged survival time. However, the beneficial effects of RSV were greatly abrogated by Ex527, a selective inhibitor of SIRT1. These results suggest a therapeutic role for SIRT1 in the reversal of AKI in septic rat, which may rely on SIRT3-mediated deacetylation of SOD2. SIRT1/3 activation could therefore be a promising therapeutic strategy to treat sepsis-associated AKI.

Topics: Acetylation; Acute Kidney Injury; Animals; Apoptosis; Carbazoles; Cecum; Disease Models, Animal; Enzyme Activation; Epithelial Cells; Female; Histone Deacetylase Inhibitors; Kidney Tubules; Ligation; Male; Mitochondria; Oxidative Stress; Punctures; Rats, Sprague-Dawley; Resveratrol; Sepsis; Signal Transduction; Sirtuin 1; Sirtuins; Stilbenes; Superoxide Dismutase

Mechanism-based sepsis treatments are unavailable, and their incidence is rising worldwide. Deaths occur during the early acute phase of hyperinflammation or subsequent postacute hypoinflammatory phase with sustained organ failure. The acute sepsis phase shifts rapidly, and multiple attempts to treat early excessive inflammation have uniformly failed. We reported in a sepsis cell model and human sepsis blood leukocytes that nuclear NAD+ sensor SIRT1 deacetylase remodels chromatin at specific gene sets to switch the acute-phase proinflammatory response to hypoinflammatory. Importantly, SIRT1 chromatin reprogramming is reversible, suggesting that inhibition of SIRT1 might reverse postacute-phase hypoinflammation. We tested this concept in septic mice, using the highly specific SIRT1 inhibitor EX-527, a small molecule that closes the NAD+ binding site of SIRT1. Strikingly, when administered 24 h after sepsis, all treated animals survived, whereas only 40% of untreated mice survived. EX-527 treatment reversed the inability of leukocytes to adhere at the small intestine MVI, reversed in vivo endotoxin tolerance, increased leukocyte accumulation in peritoneum, and improved peritoneal bacterial clearance. Mechanistically, the SIRT1 inhibitor restored repressed endothelial E-selectin and ICAM-1 expression and PSGL-1 expression on the neutrophils. Systemic benefits of EX-527 treatment included stabilized blood pressure, improved microvascular blood flow, and a shift toward proimmune macrophages in spleen and bone marrow. Our findings reveal that modifying the SIRT1 NAD+ axis may provide a novel way to treat sepsis in its hypoinflammatory phase.

Topics: Animals; Bone Marrow Cells; Carbazoles; Endothelial Cells; Endotoxins; Gene Expression Regulation; Immune Tolerance; Immunity; Immunity, Innate; Inflammation; Intestinal Mucosa; Intestine, Small; Leukocytes; Membrane Glycoproteins; Mice; Phenotype; Sepsis; Sirtuin 1; Spleen

We have recently demonstrated that inhibition of histone deacetylase (HDAC) Class I, II, and IV with nonspecific HDAC inhibitors improves survival in a mouse model of lethal cecal ligation and puncture (CLP). However, the consequence of HDAC Class III inhibition is unknown in this model. The aims of the present study were to explore the effect of EX-527, a selective Sirtuin 1 (SIRT1) inhibitor, on survival in the lethal model of CLP-sepsis and to assess the impact of the treatment on inflammatory cytokine production, coagulopathy, and bone marrow atrophy during severe sepsis.. For Experiment I, C57BL/6J mice were subjected to CLP and, 1 hour later, intraperitoneally injected with either EX-527 dissolved in dimethyl sulfoxide (DMSO) or DMSO only. Survival was monitored for 10 days. For Experiment II, 1 hour after CLP animals were randomly treated with (1) DMSO vehicle and (2) EX-527. Peritoneal fluid and blood samples were collected for measurement of cytokines, and blood was also used to evaluate coagulation status using thrombelastography. In addition, long bones (femurs and tibias) were examined to determine morphologic changes in the marrow by hematoxylin and eosin staining. For Experiment III, normal primary splenocytes were cultured and treated with lipopolysaccharide in the presence or absence of EX-527 to assess cytokine production.. EX-527 significantly improved survival (50% vs. 0% survival as compared to vehicle, p = 0.0007) and attenuated levels of cytokines tumor necrosis factor α and interleukin 6 in the blood and the peritoneal fluid compared with the vehicle control. It also decreased tumor necrosis factor α and interleukin 6 production by splenocytes in vitro. Selective inhibition of SIRT1 was associated with significant improvements in fibrin cross-linkage, platelet function, and clot rigidity but had no significant impact on the clot initiation parameters. Moreover, inhibition of SIRT1 was associated with a significant decrease in bone marrow atrophy.. Selective inhibition of Class III HDAC SIRT1 significantly improves survival, attenuates cytokine levels and sepsis-associated coagulopathy, and decreases bone marrow atrophy in a lethal mouse septic model.

Topics: Animals; Blood Coagulation; Carbazoles; Disease Models, Animal; Femur; Histone Deacetylase Inhibitors; Histone Deacetylases; Interleukin-6; Male; Mice, Inbred C57BL; Sepsis; Thrombelastography; Tibia; Tumor Necrosis Factor-alpha