scholarly journals Dexmedetomidine Ameliorates Hippocampus Injury and Cognitive Dysfunction Induced by Hepatic Ischemia/Reperfusion by Activating SIRT3-Mediated Mitophagy and Inhibiting Activation of the NLRP3 Inflammasome in Young Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Wenli Yu ◽  
Jingshu Lyu ◽  
Lili Jia ◽  
Mingwei Sheng ◽  
Hongli Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion ◽  
Mitochondrial Protein ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Protective Effects ◽  
Hepatic Ischemia ◽  
Nlrp3 Inflammasome Activation ◽  
Hepatic Ischemia Reperfusion

Hepatic ischemia-reperfusion (HIR) has been proven to trigger oxidative stress and pyroptosis in the hippocampus. Sirtuin 3 (SIRT3) is an essential mitochondrial protein deacetylase regulating oxidative stress and mitophagy. Dexmedetomidine (Dex) has been demonstrated to confer neuroprotection in different brain injury models. However, whether the protective effects of Dex following HIR are orchestrated by activation of SIRT3-mediated mitophagy and inhibition of NOD-like receptor protein 3 (NLRP3) inflammasome activation remains unknown. Herein, two-week-old rats were treated with Dex or a selective SIRT3 inhibitor (3-TYP)/autophagy inhibitor (3-MA) and then subjected to HIR. The results revealed that Dex treatment effectively attenuated neuroinflammation and cognitive deficits via upregulating SIRT3 expression and activity. Furthermore, Dex treatment inhibited the activation of NLRP3 inflammasome, while 3-TYP and 3-MA eliminated the protective effects of Dex, suggesting that SIRT3-mediated mitophagy executes the protective effects of Dex. Moreover, 3-TYP treatment downregulated the expression level of SIRT3 downstream proteins: forkhead-box-protein 3α (FOXO3α), superoxide dismutase 2 (SOD2), peroxiredoxin 3 (PRDX3), and cyclophilin D (CYP-D), which were barely influenced by 3-MA treatment. Notably, both 3-TYP and 3-MA were able to offset the antioxidative and antiapoptosis effects of Dex, indicating that SIRT3-mediated mitophagy may be the last step and the major pathway executing the neuroprotective effects of Dex. In conclusion, Dex inhibits HIR-induced NLRP3 inflammasome activation mainly by triggering SIRT3-mediated mitophagy.

scholarly journals Parkin-Dependent Mitophagy is Required for the Inhibition of ATF4 on NLRP3 Inflammasome Activation in Cerebral Ischemia-Reperfusion Injury in Rats

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 897 ◽  
Author(s):  
He ◽  
Li ◽  
Meng ◽  
Wu ◽  
Zhao ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Nissl Staining ◽  
Male Adult ◽  
Cerebral Ischemia Reperfusion ◽  
Nlrp3 Inflammasome Activation

Background: Nod-like receptor protein 3 (NLRP3) inflammasome is a crucial contributor in the inflammatory process during cerebral ischemia/reperfusion (I/R) injury. ATF4 plays a pivotal role in the pathogenesis of cerebral I/R injury, however, its function and underlying mechanism are not fully characterized yet. In the current study, we examined whether ATF4 ameliorates cerebral I/R injury by inhibiting NLRP3 inflammasome activation and whether mitophagy is involved in this process. In addition, we explored the role of parkin in ATF4-mediated protective effects. Method: To address these issues, healthy male adult Sprague-Dawley rats were exposed to middle cerebral artery occlusion for 1 h followed by 24 h reperfusion. Adeno-associated virus (AAV) and siRNA were injected into rats to overexpress and knockdown ATF4 expression, respectively. After pretreatment with AAV, mdivi-1(mitochondrial division inhibitor-1) was injected into rats to block mitophagy activity. Parkin expression was knockdown using specific siRNA after AAV pretreatment. Result: Data showed that ATF4 overexpression induced by AAV was protective against cerebral I/R injury, as evidenced by reduced cerebral infraction volume, decreased neurological scores and improved outcomes of HE and Nissl staining. In addition, overexpression of ATF4 gene was able to up-regulate Parkin expression, enhance mitophagy activity and inhibit NLRP3 inflammasome-mediated inflammatory response. ATF4 knockdown induced by siRNA resulted in the opposite effects. Furthermore, ATF4-mediated inhibition of NLRP3 inflammasome activation was strongly affected by mitophagy blockage upon mdivi-1 injection. Besides, ATF4-mediated increase of mitophagy activity and inhibition of NLRP3 inflammasome activation were effectively reversed by Parkin knockdown using siRNA. Conclusion: Our study demonstrated that ATF4 is able to alleviate cerebral I/R injury by suppressing NLRP3 inflammasome activation through parkin-dependent mitophagy activity. These results may provide a new strategy to relieve cerebral I/R injury by modulating mitophagy-NLRP3 inflammasome axis.

scholarly journals Mild Hypothermia Attenuates Hepatic Ischemia–Reperfusion Injury through Regulating the JAK2/STAT3-CPT1a-Dependent Fatty Acid β-Oxidation

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Wei Wang ◽  
Xiaoyan Hu ◽  
Zhiping Xia ◽  
Zhongzhong Liu ◽  
Zibiao Zhong ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Fatty Acid ◽  
Mild Hypothermia ◽  
Ischemia Reperfusion ◽  
Protective Effects ◽  
Hepatic Enzyme ◽  
Hepatocyte Apoptosis ◽  
Hepatic Ischemia ◽  
Mitochondrial Injury ◽  
Hepatic Ischemia Reperfusion

Hepatic ischemia–reperfusion (IR) injury is a clinical issue that can result in poor outcome and lacks effective therapies at present. Mild hypothermia (32–35°C) is a physiotherapy that has been reported to significantly alleviate IR injury, while its protective effects are attributed to multiple mechanisms, one of which may be the regulation of fatty acid β-oxidation (FAO). The aim of the present study was to investigate the role and underlying mechanisms of FAO in the protective effects of mild hypothermia. We used male mice to establish the experimental models as previously described. In brief, before exposure to in situ ischemia for 1 h and reperfusion for 6 h, mice received pretreatment with mild hypothermia for 2 h and etomoxir (inhibitor of FAO) or leptin (activator of FAO) for 1 h, respectively. Then, tissue and blood samples were collected to evaluate the liver injury, oxidative stress, and changes in hepatic FAO. We found that mild hypothermia significantly reduced the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury. In addition, the expression of the rate-limiting enzyme (CPT1a) of hepatic FAO was downregulated almost twofold by IR, while this inhibition could be significantly reversed by mild hypothermia. Experiments with leptin and etomoxir confirmed that activation of FAO could also reduce the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury induced by IR, which had the similar effects to mild hypothermia, while inhibition of FAO had negative effects. Furthermore, mild hypothermia and leptin could promote the phosphorylation of JAK2/STAT3 and upregulate the ratio of BCL-2/BAX to suppress hepatocyte apoptosis. Thus, we concluded that FAO played an important role in hepatic IR injury and mild hypothermia attenuated hepatic IR injury mainly via the regulation of JAK2/STAT3-CPT1a-dependent FAO.

scholarly journals NLRP3 Inflammasome Activation-Mediated Pyroptosis Aggravates Myocardial Ischemia/Reperfusion Injury in Diabetic Rats

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Zhen Qiu ◽  
Shaoqing Lei ◽  
Bo Zhao ◽  
Yang Wu ◽  
Wating Su ◽  
...  
Keyword(s):  
Cell Death ◽  
Myocardial Ischemia ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion ◽  
Diabetic Rats ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Myocardial Infarct Size ◽  
Nlrp3 Inflammasome Activation ◽  
Myocardial Ischemia Reperfusion

The reactive oxygen species- (ROS-) induced nod-like receptor protein-3 (NLRP3) inflammasome triggers sterile inflammatory responses and pyroptosis, which is a proinflammatory form of programmed cell death initiated by the activation of inflammatory caspases. NLRP3 inflammasome activation plays an important role in myocardial ischemia/reperfusion (MI/R) injury. Our present study investigated whether diabetes aggravated MI/R injury through NLRP3 inflammasome-mediated pyroptosis. Type 1 diabetic rat model was established by intraperitoneal injection of streptozotocin (60 mg/kg). MI/R was induced by ligating the left anterior descending artery (LAD) for 30 minutes followed by 2 h reperfusion. H9C2 cardiomyocytes were exposed to high glucose (HG, 30 mM) conditions and hypoxia/reoxygenation (H/R) stimulation. The myocardial infarct size, CK-MB, and LDH release in the diabetic rats subjected to MI/R were significantly higher than those in the nondiabetic rats, accompanied with increased NLRP3 inflammasome activation and increased pyroptosis. Inhibition of inflammasome activation with BAY11-7082 significantly decreased the MI/R injury.In vitrostudies showed similar effects, as BAY11-7082 or the ROS scavenger N-acetylcysteine, attenuated HG and H/R-induced H9C2 cell injury. In conclusion, hyperglycaemia-induced NLRP3 inflammasome activation may be a ROS-dependent process in pyroptotic cell death, and NLRP3 inflammasome-induced pyroptosis aggravates MI/R injury in diabetic rats.

scholarly journals Neuronal GPR30 Participates in Genistein-Mediated Neuroprotection in Ischemic Stroke by Inhibiting NLRP3 Inflammasome Activation in Ovariectomized Female Mice

2021 ◽  
Author(s):  
Shiquan Wang ◽  
Zhen Zhang ◽  
Jin Wang ◽  
Lina Ma ◽  
Jianshuai Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion ◽  
Underlying Mechanism ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Peroxisome Proliferator ◽  
Neuroprotective Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Nlrp3 Inflammasome Activation

Abstract Estrogen replacement therapy (ERT) is potentially beneficial for the prevention and treatment of postmenopausal cerebral ischemia but inevitably increases the risk of cerebral hemorrhage and breast cancer when used for a long period of time. Genistein, a natural phytoestrogen, has been reported to contribute to the recovery of postmenopausal ischemic stroke with reduced risks. However, the underlying mechanism of genistein-mediated neuroprotection remains unclear. We reported that genistein exerted significant neuroprotective effects by enhancing the expression of neuronal G protein-coupled receptor 30 (GPR30) in the ischemic penumbra after cerebral reperfusion in ovariectomized (OVX) mice, and this effect was achieved through GPR30-mediated inhibition of nod-like receptor protein 3 (NLRP3) inflammasome activation. In addition, we found that Peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) was the pivotal molecule that participated in GPR30-mediated inhibition of NLRP3 inflammasome activation in OVX mice after ischemia/reperfusion (I/R) injury. Our data suggest that the neuronal GPR30/PGC-1α pathway plays an important role in genistein-mediated neuroprotection against I/R injury in OVX mice.

scholarly journals Orientin Ameliorates LPS-Induced Inflammatory Responses through the Inhibitory of the NF-κB Pathway and NLRP3 Inflammasome

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Qingfei Xiao ◽  
Zhihui Qu ◽  
Ying Zhao ◽  
Liming Yang ◽  
Pujun Gao
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Receptor Protein ◽  
Raw 264.7 Cells ◽  
Prostaglandin E ◽  
Inflammasome Activation ◽  
Therapeutic Effects ◽  
Protective Effects ◽  
Nlrp3 Inflammasome Activation ◽  
Underlying Mechanisms

Inflammation is a complex response to diverse pathological conditions, resulting in negative rather than protective effects when uncontrolled. Orientin (Ori), a flavonoid component isolated from natural plants, possesses abundant properties. Thus, we aimed to discover the potential therapeutic effects of orientin on lipopolysaccharide- (LPS-) induced inflammation in RAW 264.7 cells and the underlying mechanisms. In our studies, we evaluated the effects of Ori on proinflammatory mediator production stimulated by LPS, including tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, IL-18, and IL-1β, along with prostaglandin E2 (PGE2) and NO. Our data indicated that orientin dramatically inhibited the levels of these mediators. Consistent with these results, the expression levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were also reduced. Further study demonstrated that such inhibitory effects of Ori were due to suppression of the nuclear factor-kappa B (NF-κB) pathway and nucleotide-binding domain- (NOD-) like receptor protein 3 (NLRP3) inflammasome activation, which may contribute to its anti-inflammatory effects. Together, these findings show that Ori may be an effective candidate for ameliorating LPS-induced inflammatory responses.

scholarly journals Inhibition of oxidative stress and NLRP3 inflammasome by Saikosaponin-d alleviates acute liver injury in carbon tetrachloride-induced hepatitis in mice

2020 ◽  
Vol 34 ◽  
pp. 205873842095059
Author(s):  
Yirong Chen ◽  
Renye Que ◽  
Liubing Lin ◽  
Yanting Shen ◽  
Jinkai Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Carbon Tetrachloride ◽  
Liver Injury ◽  
Nlrp3 Inflammasome ◽  
Acute Liver Injury ◽  
Inflammasome Activation ◽  
Protective Effects ◽  
Mice Model ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation

NLRP3 inflammasome activation results in severe liver inflammation and injury. Saikosaponin-d (SSd) possesses anti-inflammatory and hepatoprotective effects. This study aimed to determine the protective effects of SSd on carbon tetrachloride (CCl4)-induced acute liver injury in mice, and whether oxidative stress and NLRP3 inflammasome activation participate in the process. The CCl4 mice model and controls were induced. The mice were treated with SSd at 1, 1.5, or 2.0 mg/kg in a total volume of 100 µl/25 g of body weight. Liver injury was assessed by histopathology. Oxidative stress was determined using mitochondrial superoxide production (MSP), malondialdehyde (MDA) content, and superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities. NLRP3, ASC, and Caspase 1 were determined by real-time PCR and western blot. IL-1β and IL-18 levels were determined by ELISA. Significantly elevated oxidative stress was induced in the liver by CCl4, as demonstrated by histopathology and increases of MDA and MSP levels and decreases of SOD, GPx, and CAT activities (all P < 0.01). SSd significantly decreased the MDA and MSP levels and increased the activities of SOD, GPx, and CAT (all P < 0.05). The mRNA expression of NLRP3, ASC, and Caspase 1, and the protein expression of Caspase 1-p10, NLRP3, ASC, IL-1β, and IL-18 were significantly increased after CCl4 induction (all P < 0.01). These changes were reversed by SSd (all P < 0.05). Suppression of the oxidative stress and NLRP3 inflammasome activation were involved in SSd-alleviated acute liver injury in CCl4-induced hepatitis.

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