scholarly journals cGAS-mediated autophagy protects the liver from ischemia-reperfusion injury independently of STING

2018 ◽  
Vol 314 (6) ◽  
pp. G655-G667 ◽  
Author(s):  
Zhao Lei ◽  
Meihong Deng ◽  
Zhongjie Yi ◽  
Qian Sun ◽  
Richard A. Shapiro ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Adenosine Monophosphate ◽  
Cyclic Guanosine Monophosphate ◽  
Protective Role ◽  
Guanosine Monophosphate ◽  
Independent Manner

Liver ischemia-reperfusion (I/R) injury occurs through induction of oxidative stress and release of damage-associated molecular patterns (DAMPs), including cytosolic DNA released from dysfunctional mitochondria or from the nucleus. Cyclic guanosine monophosphate–adenosine monophosphate (cGAMP) synthase (cGAS) is a cytosolic DNA sensor known to trigger stimulator of interferon genes (STING) and downstream type 1 interferon (IFN-I) pathways, which are pivotal innate immune system responses to pathogen. However, little is known about the role of cGAS/STING in liver I/R injury. We subjected C57BL/6 (WT), cGAS knockout (cGAS−/−), and STING-deficient (STINGgt/gt) mice to warm liver I/R injury and that found cGAS−/− mice had significantly increased liver injury compared with WT or STINGgt/gt mice, suggesting a protective effect of cGAS independent of STING. Liver I/R upregulated cGAS in vivo and also in vitro in hepatocytes subjected to anoxia/reoxygenation (A/R). We confirmed a previously published finding that hepatocytes do not express STING under normoxic conditions or after A/R. Hepatocytes and liver from cGAS−/− mice had increased cell death and reduced induction of autophagy under hypoxic conditions as well as increased apoptosis. Protection could be restored in cGAS−/− hepatocytes by overexpression of cGAS or by pretreatment of mice with autophagy inducer rapamycin. Our findings indicate a novel protective role for cGAS in the regulation of autophagy during liver I/R injury that occurs independently of STING. NEW & NOTEWORTHY Our studies are the first to document the important role of cGAS in the acute setting of sterile injury induced by I/R. Specifically, we provide evidence that cGAS protects liver from I/R injury in a STING-independent manner.

scholarly journals STIM1/Orai1-mediated SOCE: current perspectives and potential roles in cardiac function and pathology

2013 ◽  
Vol 305 (4) ◽  
pp. H446-H458 ◽  
Author(s):  
Helen E. Collins ◽  
Xiaoyuan Zhu-Mauldin ◽  
Richard B. Marchase ◽  
John C. Chatham
Keyword(s):  
Cardiac Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Molecular Regulation ◽  
Cardiomyocyte Hypertrophy ◽  
Substantial Evidence ◽  
Contraction Coupling

Store-operated Ca2+ entry (SOCE) is critical for Ca2+ signaling in nonexcitable cells; however, its role in the regulation of cardiomyocyte Ca2+ homeostasis has only recently been investigated. The increased understanding of the role of stromal interaction molecule 1 (STIM1) in regulating SOCE combined with recent studies demonstrating the presence of STIM1 in cardiomyocytes provides support that this pathway co-exists in the heart with the more widely recognized Ca2+ handling pathways associated with excitation-contraction coupling. There is now substantial evidence that STIM1-mediated SOCE plays a key role in mediating cardiomyocyte hypertrophy, both in vitro and in vivo, and there is growing support for the contribution of SOCE to Ca2+ overload associated with ischemia/reperfusion injury. Here, we provide an overview of our current understanding of the molecular regulation of SOCE and discuss the evidence supporting the role of STIM1/Orai1-mediated SOCE in regulating cardiomyocyte function.

scholarly journals Up-regulation of MicroRNA-21 Mediates Isoflurane-induced Protection of Cardiomyocytes

2015 ◽  
Vol 122 (4) ◽  
pp. 795-805 ◽  
Author(s):  
Jessica M. Olson ◽  
Yasheng Yan ◽  
Xiaowen Bai ◽  
Zhi-Dong Ge ◽  
Mingyu Liang ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Messenger Rna ◽  
Functional Role ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cell Death Protein

Abstract Background: Anesthetic cardioprotection reduces myocardial infarct size after ischemia–reperfusion injury. Currently, the role of microRNA in this process remains unknown. MicroRNAs are short, noncoding nucleotide sequences that negatively regulate gene expression through degradation or suppression of messenger RNA. In this study, the authors uncovered the functional role of microRNA-21 (miR-21) up-regulation after anesthetic exposure. Methods: MicroRNA and messenger RNA expression changes were analyzed by quantitative real-time polymerase chain reaction in cardiomyocytes after exposure to isoflurane. Lactate dehydrogenase release assay and propidium iodide staining were conducted after inhibition of miR-21. miR-21 target expression was analyzed by Western blot. The functional role of miR-21 was confirmed in vivo in both wild-type and miR-21 knockout mice. Results: Isoflurane induces an acute up-regulation of miR-21 in both in vivo and in vitro rat models (n = 6, 247.8 ± 27.5% and 258.5 ± 9.0%), which mediates protection to cardiomyocytes through down-regulation of programmed cell death protein 4 messenger RNA (n = 3, 82.0 ± 4.9% of control group). This protective effect was confirmed by knockdown of miR-21 and programmed cell death protein 4 in vitro. In addition, the protective effect of isoflurane was abolished in miR-21 knockout mice in vivo, with no significant decrease in infarct size compared with nonexposed controls (n = 8, 62.3 ± 4.6% and 56.2 ± 3.2%). Conclusions: The authors demonstrate for the first time that isoflurane mediates protection of cardiomyocytes against oxidative stress via an miR-21/programmed cell death protein 4 pathway. These results reveal a novel mechanism by which the damage done by ischemia/reperfusion injury may be decreased.

scholarly journals Naringenin Attenuates Myocardial Ischemia-Reperfusion Injury via cGMP-PKGIα Signaling and In Vivo and In Vitro Studies

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Li-Ming Yu ◽  
Xue Dong ◽  
Jian Zhang ◽  
Zhi Li ◽  
Xiao-Dong Xue ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Myocardial Ischemia ◽  
Er Stress ◽  
Ischemia Reperfusion Injury ◽  
Heart Function ◽  
Ischemia Reperfusion ◽  
Guanosine Monophosphate ◽  
Myocardial Ischemia Reperfusion

Endoplasmic reticulum (ER) stress and oxidative stress contribute greatly to myocardial ischemia-reperfusion (MI/R) injury. Naringenin, a flavonoid derived from the citrus genus, exerts cardioprotective effects. However, the effects of naringenin on ER stress as well as oxidative stress under MI/R condition and the detailed mechanisms remain poorly defined. This study investigated the protective effect of naringenin on MI/R-injured heart with a focus on cyclic guanosine monophosphate- (cGMP-) dependent protein kinase (PKG) signaling. Sprague-Dawley rats were treated with naringenin (50 mg/kg/d) and subjected to MI/R surgery with or without KT5823 (2 mg/kg, a selective inhibitor of PKG) cotreatment. Cellular experiment was conducted on H9c2 cardiomyoblasts subjected to simulated ischemia-reperfusion treatment. Before the treatment, the cells were incubated with naringenin (80 μmol/L). PKGIα siRNA was employed to inhibit PKG signaling. Our in vivo and in vitro data showed that naringenin effectively improved heart function while it attenuated myocardial apoptosis and infarction. Furthermore, pretreatment with naringenin suppressed MI/R-induced oxidative stress as well as ER stress as evidenced by decreased superoxide generation, myocardial MDA level, gp91phox expression, and phosphorylation of PERK, IRE1α, and EIF2α as well as reduced ATF6 and CHOP. Importantly, naringenin significantly activated myocardial cGMP-PKGIα signaling while inhibition of PKG signaling with KT5823 (in vivo) or siRNA (in vitro) not only abolished these actions but also blunted naringenin’s inhibitory effects against oxidative stress and ER stress. In summary, our study demonstrates that naringenin treatment protects against MI/R injury by reducing oxidative stress and ER stress via cGMP-PKGIα signaling. Its cardioprotective effect deserves further clinical study.

scholarly journals MiR-298 Exacerbates Ischemia/Reperfusion Injury Following Ischemic Stroke by Targeting Act1

2018 ◽  
Vol 48 (2) ◽  
pp. 528-539 ◽  
Author(s):  
Hongxue Sun ◽  
Di Zhong ◽  
Cheng Wang ◽  
Yilei Sun ◽  
Jiaying Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Neurological Deficits ◽  
Luciferase Assay ◽  
Regulatory Relationship

Background/Aims: This study investigated the role of the microRNA miR-298 and its target Act1 in ischemic stroke. Methods: Cell viability was assessed with the 3-(4,5-dimethythiazol-2- yl)-2,5-diphenyl tetrazolium bromide assay. Apoptotic cells were detected by flow cytometry, and mRNA and protein expression were assessed by quantitative real-time PCR and western blotting, respectively. The regulatory relationship between miR-298 and Act1 was evaluated with the luciferase assay. To clarify the role of Act1 following ischemic stroke, the transcript was knocked down by short interfering RNA. The in vitro findings were validated in a mouse model of middle cerebral artery occlusion by administration of miR-298 mimic. Results: Act1 was upregulated whereas miR-298 was downregulated in ischemic stroke. miR-298 overexpression by transfection of a mimic suppressed Act1 protein levels in vitro and in vivo, and the luciferase assay showed that miR-298 directly binds to the 3’ untranslated region of the Act1 transcript. miR-298 overexpression enhanced cell apoptosis and autophagy and exacerbated ischemic infarction and neurological deficits, effects that were exerted via negative regulation of Act1/c-Jun N-terminal kinase (JNK)/nuclear factor (NF)-κB signaling and downstream autophagy pathways. Conclusions: Upregulation of miR-298 following ischemic stroke promotes brain injury in vitro and vivo by inhibiting the Act1/JNK/NF-κB signaling cascade and the downstream autophagy pathway. Therapeutic strategies that target miR-298 could be beneficial for the treatment of ischemic stroke.

scholarly journals Norswertianolin Promotes Cystathionine γ-Lyase Activity and Attenuates Renal Ischemia/Reperfusion Injury and Hypertension

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaping Niu ◽  
Congkuo Du ◽  
Changting Cui ◽  
Haizeng Zhang ◽  
Yue Deng ◽  
...  
Keyword(s):  
Cardiovascular Diseases ◽  
Small Molecule ◽  
Ischemia Reperfusion Injury ◽  
Specific Binding ◽  
Ischemia Reperfusion ◽  
Mrna Level ◽  
Protective Role ◽  
Spontaneously Hypertensive

Cystathionine gamma-lyase (CSE)/hydrogen sulfide (H2S) plays a protective role in cardiovascular diseases including hypertension and ischemia/reperfusion (I/R) injury. This study was aimed to screen natural small molecule compounds that activate CSE activity and then evaluate its effect(s) on kidney I/R injury and hypertension. Applying computer molecular docking technology, we screened the natural small molecule compound norswertianolin (NW)-specific binding to CSE. Using the microscale thermophoresis technology, we confirmed that the Leu68 site was the essential hydrogen bond site of NW binding to CSE. NW supplementation significantly increased CSE expression and its activity for H2S generation both in vivo and in vitro. In the model of acute and long-term kidney I/R injury, NW pretreatment dramatically attenuated kidney damage, associated with decreasing blood urea nitrogen (BUN), serum creatinine (Cr) level, reactive oxygen species (ROS) production, and cleaved caspase 3 expression. In spontaneously hypertensive rats (SHRs), NW treatment also lowered blood pressure, the media/lumen ratio of the femoral artery, and the mRNA level of inflammatory cytokines. In conclusion, NW acts as a novel small molecular chemical compound CSE agonist, directly binding to CSE, heightening CSE generation–H2S activity, and then alleviating kidney I/R injury and hypertension. NW has a potential therapeutic merit for cardiovascular diseases.

scholarly journals PGC-1α Protects against Hepatic Ischemia Reperfusion Injury by Activating PPARα and PPARγ and Regulating ROS Production

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Chaoqun Wang ◽  
Zihao Li ◽  
Baolei Zhao ◽  
Yaohua Wu ◽  
Yao Fu ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Peroxisome Proliferator ◽  
Hepatic Ischemia ◽  
Peroxisome Proliferator Activated Receptors ◽  
Hepatic Ischemia Reperfusion ◽  
Serum Aminotransferases

Peroxisome proliferator-activated receptors (PPARs) α and γ have been shown to be protective in hepatic ischemia/reperfusion (I/R) injury. However, the precise role of PPARγ coactivator-1α (PGC-1α), which can coactivate both of these receptors, in hepatic I/R injury, remains largely unknown. This study was designed to test our hypothesis that PGC-1α is protective during hepatic I/R injury in vitro and in vivo. Our results show that endogenous PGC-1α is basally expressed in normal livers and is moderately increased by I/R. Ectopic PGC-1α protects against hepatic I/R and hepatocyte anoxia/reoxygenation (A/R) injuries, whereas knockdown of endogenous PGC-1α aggravates such injuries, as evidenced by assessment of the levels of serum aminotransferases and inflammatory cytokines, necrosis, apoptosis, cell viability, and histological examination. The EMSA assay shows that the activation of PPARα and PPARγ is increased or decreased by the overexpression or knockdown of PGC-1α, respectively, during hepatic I/R and hepatocyte A/R injuries. In addition, the administration of specific antagonists of either PPARα (MK886) or PPARγ (GW9662) can effectively decrease the protective effect of PGC-1α against hepatic I/R and hepatocyte A/R injuries. We also demonstrate an important regulatory role of PGC-1α in reactive oxygen species (ROS) metabolism during hepatic I/R, which is correlated with the induction of ROS-detoxifying enzymes and is also dependent on the activations of PPARα and PPARγ. These data demonstrate that PGC-1α protects against hepatic I/R injury, mainly by regulating the activation of PPARα and PPARγ. Thus, PGC-1α may be a promising therapeutic target for the protection of the liver against I/R injury.

Cardioprotective role of endogenous hydrogen peroxide during ischemia-reperfusion injury in canine coronary microcirculation in vivo

2006 ◽  
Vol 291 (3) ◽  
pp. H1138-H1146 ◽  
Author(s):  
Toyotaka Yada ◽  
Hiroaki Shimokawa ◽  
Osamu Hiramatsu ◽  
Yoshisuke Haruna ◽  
Yoshitaka Morita ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Protective Role ◽  
No Production ◽  
Coronary Vasodilatation ◽  
Before And After ◽  
Nos Inhibitor

We have recently demonstrated that endogenous H2O2 plays an important role in coronary autoregulation in vivo. However, the role of H2O2 during coronary ischemia-reperfusion (I/R) injury remains to be examined. In this study, we examined whether endogenous H2O2 also plays a protective role in coronary I/R injury in dogs in vivo. Canine subepicardial small coronary arteries (≥100 μm) and arterioles (<100 μm) were continuously observed by an intravital microscope during coronary I/R (90/60 min) under cyclooxygenase blockade ( n = 50). Coronary vascular responses to endothelium-dependent vasodilators (ACh) were examined before and after I/R under the following seven conditions: control, nitric oxide (NO) synthase (NOS) inhibitor NG-monomethyl-l-arginine (l-NMMA), catalase (a decomposer of H2O2), 8-sulfophenyltheophylline (8-SPT, an adenosine receptor blocker), l-NMMA + catalase, l-NMMA + tetraethylammonium (TEA, an inhibitor of large-conductance Ca2+-sensitive potassium channels), and l-NMMA + catalase + 8-SPT. Coronary I/R significantly impaired the coronary vasodilatation to ACh in both sized arteries (both P < 0.01); l-NMMA reduced the small arterial vasodilatation (both P < 0.01), whereas it increased ( P < 0.05) the ACh-induced coronary arteriolar vasodilatation associated with fluorescent H2O2 production after I/R. Catalase increased the small arterial vasodilatation ( P < 0.01) associated with fluorescent NO production and increased endothelial NOS expression, whereas it decreased the arteriolar response after I/R ( P < 0.01). l-NMMA + catalase, l-NMMA + TEA, or l-NMMA + catalase + 8-SPT further decreased the coronary vasodilatation in both sized arteries (both, P < 0.01). l-NMMA + catalase, l-NMMA + TEA, and l-NMMA + catalase + 8-SPT significantly increased myocardial infarct area compared with the other four groups (control, l-NMMA, catalase, and 8-SPT; all, P < 0.01). These results indicate that endogenous H2O2, in cooperation with NO, plays an important cardioprotective role in coronary I/R injury in vivo.

scholarly journals Regulatory T cells are strong promoters of acute ischemic stroke in mice by inducing dysfunction of the cerebral microvasculature

Blood ◽  
2013 ◽  
Vol 121 (4) ◽  
pp. 679-691 ◽  
Author(s):  
Christoph Kleinschnitz ◽  
Peter Kraft ◽  
Angela Dreykluft ◽  
Ina Hagedorn ◽  
Kerstin Göbel ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Ischemia Reperfusion Injury ◽  
Thrombus Formation ◽  
Ischemia Reperfusion ◽  
T Cell Subsets ◽  
Ischemic Brain

Abstract We have recently identified T cells as important mediators of ischemic brain damage, but the contribution of the different T-cell subsets is unclear. Forkhead box P3 (FoxP3)–positive regulatory T cells (Tregs) are generally regarded as prototypic anti-inflammatory cells that maintain immune tolerance and counteract tissue damage in a variety of immune-mediated disorders. In the present study, we examined the role of Tregs after experimental brain ischemia/reperfusion injury. Selective depletion of Tregs in the DEREG mouse model dramatically reduced infarct size and improved neurologic function 24 hours after stroke and this protective effect was preserved at later stages of infarct development. The specificity of this detrimental Treg effect was confirmed by adoptive transfer experiments in wild-type mice and in Rag1−/− mice lacking lymphocytes. Mechanistically, Tregs induced microvascular dysfunction in vivo by increased interaction with the ischemic brain endothelium via the LFA-1/ICAM-1 pathway and platelets and these findings were confirmed in vitro. Ablation of Tregs reduced microvascular thrombus formation and improved cerebral reperfusion on stroke, as revealed by ultra-high-field magnetic resonance imaging at 17.6 Tesla. In contrast, established immunoregulatory characteristics of Tregs had no functional relevance. We define herein a novel and unexpected role of Tregs in a primary nonimmunologic disease state.

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