scholarly journals Regulation of the Transcription Factor EB-PGC1α Axis by Beclin-1 Controls Mitochondrial Quality and Cardiomyocyte Death under Stress

2015 ◽  
Vol 35 (6) ◽  
pp. 956-976 ◽  
Author(s):  
Xiucui Ma ◽  
Haiyan Liu ◽  
John T. Murphy ◽  
Sarah R. Foyil ◽  
Rebecca J. Godar ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Beclin 1 ◽  
Ros Generation ◽  
Mtor Inhibition ◽  
Lysosome Biogenesis ◽  
Transcription Factor Eb ◽  
Inducible Protein

In cardiac ischemia-reperfusion injury, reactive oxygen species (ROS) generation and upregulation of the hypoxia-inducible protein BNIP3 result in mitochondrial permeabilization, but impairment in autophagic removal of damaged mitochondria provokes programmed cardiomyocyte death. BNIP3 expression and ROS generation result in upregulation of beclin-1, a protein associated with transcriptional suppression of autophagy-lysosome proteins and reduced activation of transcription factor EB (TFEB), a master regulator of the autophagy-lysosome machinery. Partial beclin-1 knockdown transcriptionally stimulates lysosome biogenesis and autophagy via mTOR inhibition and activation of TFEB, enhancing removal of depolarized mitochondria. TFEB activation concomitantly stimulates mitochondrial biogenesis via PGC1α induction to restore normally polarized mitochondria and attenuate BNIP3- and hypoxia-reoxygenation-induced cell death. Conversely, overexpression of beclin-1 activates mTOR to inhibit TFEB, resulting in declines in lysosome numbers and suppression of PGC1α transcription. Importantly, knockdown of endogenous TFEB or PGC1α results in a complete or partial loss, respectively, of the cytoprotective effects of partial beclin-1 knockdown, indicating a critical role for both mitochondrial autophagy and biogenesis in ensuring cellular viability. These studies uncover a transcriptional feedback loop for beclin-1-mediated regulation of TFEB activation and implicate a central role for TFEB in coordinating mitochondrial autophagy with biogenesis to restore normally polarized mitochondria and prevent ischemia-reperfusion-induced cardiomyocyte death.

scholarly journals ELAVL1 is transcriptionally activated by FOXC1 and promotes ferroptosis in myocardial ischemia/reperfusion injury by regulating autophagy

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Hui-Yong Chen ◽  
Ze-Zhou Xiao ◽  
Xiao Ling ◽  
Rong-Ning Xu ◽  
Peng Zhu ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Beclin 1 ◽  
Myocardial Cells ◽  
Myocardial Ischemia And Reperfusion ◽  
Functional Roles ◽  
Cellular Iron ◽  
Luciferase Activity Assay ◽  
Myocardial Ischemia Reperfusion

Abstract Aims Myocardial ischemia is the most common form of cardiovascular disease and the leading cause of morbidity and mortality. Understanding the mechanisms is very crucial for the development of effective therapy. Therefore, this study aimed to investigate the functional roles and mechanisms by which ELAVL1 regulates myocardial ischemia and reperfusion (I/R) injury. Methods Mouse myocardial I/R model and cultured myocardial cells exposed to hypoxia/reperfusion (H/R) were used in this study. Features of ferroptosis were evidenced by LDH activity, GPx4 activity, cellular iron, ROS, LPO, and GSH levels. The expression levels of autophagy markers (Beclin-1, p62, LC3), ELAVL1 and FOXC1 were measured by qRT-PCR, immunostaining and western blot. RIP assay, biotin-pull down, ChIP and dual luciferase activity assay were employed to examine the interactions of ELAVL1/Beclin-1 mRNA and FOXC1/ELAVL1 promoter. CCK-8 assay was used to examine viability of cells. TTC staining was performed to assess the myocardial I/R injury. Results Myocardial I/R surgery induced ferroptosis and up-regulated ELAVL1 level. Knockdown of ELAVL1 decreased ferroptosis and ameliorated I/R injury. Si-ELAVL1 repressed autophagy and inhibition of autophagy by inhibitor suppressed ferroptosis and I/R injury in myocardial cells. Increase of autophagy could reverse the effects of ELAVL1 knockdown on ferroptosis and I/R injury. ELAVL1 directly bound with and stabilized Beclin-1 mRNA. Furthermore, FOXC1 bound to ELAVL1 promoter region and activated its transcription upon H/R exposure. Conclusion FOXC1 transcriptionally activated ELAVL1 may promote ferroptosis during myocardial I/R by modulating autophagy, leading to myocardial injury. Inhibition of ELAVL1-mediated autophagic ferroptosis would be a new viewpoint in the treatment of myocardial I/R injury.

Role of Platelet-Activating Factor in Cardiovascular Pathophysiology

2000 ◽  
Vol 80 (4) ◽  
pp. 1669-1699 ◽  
Author(s):  
Giuseppe Montrucchio ◽  
Giuseppe Alloatti ◽  
Giovanni Camussi
Keyword(s):  
Cardiovascular System ◽  
Cell Biology ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Experimental Studies ◽  
Platelet Activating Factor ◽  
Biologically Active ◽  
Endothelial Cell Migration

Platelet-activating factor (PAF) is a phospholipid mediator that belongs to a family of biologically active, structurally related alkyl phosphoglycerides. PAF acts via a specific receptor that is coupled with a G protein, which activates a phosphatidylinositol-specific phospholipase C. In this review we focus on the aspects that are more relevant for the cell biology of the cardiovascular system. The in vitro studies provided evidence for a role of PAF both as intercellular and intracellular messenger involved in cell-to-cell communication. In the cardiovascular system, PAF may have a role in embryogenesis because it stimulates endothelial cell migration and angiogenesis and may affect cardiac function because it exhibits mechanical and electrophysiological actions on cardiomyocytes. Moreover, PAF may contribute to modulation of blood pressure mainly by affecting the renal vascular circulation. In pathological conditions, PAF has been involved in the hypotension and cardiac dysfunctions occurring in various cardiovascular stress situations such as cardiac anaphylaxis and hemorrhagic, traumatic, and septic shock syndromes. In addition, experimental studies indicate that PAF has a critical role in the development of myocardial ischemia-reperfusion injury. Indeed, PAF cooperates in the recruitment of leukocytes in inflamed tissue by promoting adhesion to the endothelium and extravascular transmigration of leukocytes. The finding that human heart can produce PAF, expresses PAF receptor, and is sensitive to the negative inotropic action of PAF suggests that this mediator may have a role also in human cardiovascular pathophysiology.

Abstract 028: CCN1 Enables Fas Ligand-Induced Apoptosis by Elevating Fas Expression in Primary Cardiomyocytes or by Increasing Cytoplasmic Smac in Cardiomyoblast H9c2 Cells

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Bor-Chyuan Su ◽  
Fan-E Mo
Keyword(s):  
Cell Surface ◽  
Fas Ligand ◽  
Ischemia Reperfusion ◽  
Surface Display ◽  
Critical Role ◽  
Mitogen Activated Protein Kinase ◽  
Neonatal Rat ◽  
Ros Generation ◽  
H9c2 Cells ◽  
Induced Apoptosis

Fas/Fas ligand (FasL) is implicated in cardiac ischemia/reperfusion injury. However, cardiomyocytes in culture are resistant to FasL-induced apoptosis, suggesting that additional factor(s) are required for FasL-induced apoptosis. Matricellular protein CCN1 has been demonstrated to promote cytotoxicity of FasL in human skin fibroblasts. CCN1 is induced in a variety of cardiac pathologies. We assessed the hypothesis that CCN1 may be involved in the regulation of FasL-induced apoptosis in cardiomyocytes. We found that either FasL or CCN1 did not induce cell death in neonatal rat ventricular cardiomyocytes (NRVM). Interestingly, the combination of FasL+CCN1 generated 2-fold induction of apoptosis (vs. control p<0.001). An integrin-α 6 β 1 -binding defective mutant CCN1, CCN1-DM failed to exert synergy with FasL to induce apoptosis, indicating a critical role of α 6 β 1 . The engagement between CCN1 and α 6 β 1 instigated the elevation of cellular reactive oxygen species (ROS), the activation of mitogen activated protein kinase p38, and followed by the induction of cell surface display of Fas, thereby sensitizing NRVM to FasL-induced apoptosis. Pretreatment of the p38 inhibitor SB202190 abolished the CCN1-induced cell-surface Fas expression and the apoptosis induced by FasL+CCN1. In addition, we tested the interaction between CCN1 and FasL on the cardiomyoblast H9c2 cells. We found that FasL or CCN1 alone did not cause apoptosis in H9c2, and required the combination of FasL+CCN1 to induced apoptosis (vs. control p<0.001) in H9c2 cells, reminiscent of the observation in NRVM. Mechanistically, CCN1 acted through binding to integrin α 6 β 1 , ROS generation, and p38 activation, however, did not increase the expression of cell surface Fas for its synergy with FasL in H9c2 cells. Instead, CCN1 induced Bax translocation to mitochondria, which in turn led to the release of Smac from mitochondria to cytosol. The cytosolic Smac functions to neutralize XIAP. Smac is critical for CCN1 action, because the knockdown of Smac blunted the apoptotic activities of CCN1. In conclusion, CCN1 may play a detrimental role in a stressed heart to both the differentiated cardiomyocytes and the proliferative cardioblasts through distinct signaling mechanisms.

scholarly journals Inhibiting mTOR enhanced Cardiac STAT3 Phosphorylation at Site Ser 727 and Attenuated Myocardial Ischemia Reperfusion Injury in Diabetic Rats

2021 ◽  
Author(s):  
Xiang Xie ◽  
Zhongbao Zhao ◽  
Danyong Liu ◽  
Dengwen Zhang ◽  
Yi He ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Mtor Inhibitor ◽  
Troponin I ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Diabetic Rats ◽  
H9c2 Cells ◽  
Sprague Dawley ◽  
Mtor Inhibition ◽  
Stat3 Phosphorylation

Abstract Background Reduced levels of myocardial STAT3 activity in diabetic hearts may contribute to the increased susceptibility to ischemia-reperfusion injury (I/RI). The protein mammalian target of rapamycin (mTOR) can regulate metabolism and cell processes and plays major roles in the dynamics of I/RI. However, the role of mTOR in regulation of myocardial STAT3 and thereby affect myocardial I/RI in diabetes at relatively late stages of the disease is unknown. Methods Diabetes was induced by Streptozotocin in Sprague-Dawley rats. Myocardial I/RI was achieved with coronary occlusion for 30 minutes and reperfusion for 2 hours in absence or presence of the mTOR inhibitor rapamycin. In vitro cardiomyocyte hypoxia/re-oxygenation (H/R) was established within H9C2 cells. Results In diabetic rats, the levels of troponin-I (Tn-I), lipid peroxidation products 15-F2t-Isoprostane (15-F2t-Iso) and MDA, and the expression of protein mTOR were all significantly increased,and SOD releasing, the expression of protein phosphorylation of STAT3(p-STAT3-Ser727) were both significantly decreased compared to non-diabetic rats. Myocardial I/RI significantly increased the infract size (IS) and further increased the mTOR activation and decreased p-STAT3-Ser727 compared to diabetic rats. The selective mTOR inhibitor rapamycin reversed these changes and conferred cardioprotective effect. In H9C2 cells, high glucose (HG) significantly increased lactic dehydrogenase (LDH) release, apoptosis cells, ROS release, activation of mTOR, and decreased p-STAT3-Ser727. H/R further increased cellular injury, mTOR knock-down significantly reduced H/R injury. Conclusion Myocardial mTOR was enhanced in diabetes and contributed to I/RI. mTOR inhibition attenuated myocardial I/RI through increasing p-STAT3-Ser727.

scholarly journals Transient Receptor Potential Melastatin 2 Negatively Regulates LPS-ATP-Induced Caspase-1-Dependent Pyroptosis of Bone Marrow-Derived Macrophage by Modulating ROS Production

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Haihong Wang ◽  
Xinyi Zhou ◽  
Hui Li ◽  
Xiaowei Qian ◽  
Yan Wang ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Morphological Characteristics ◽  
Receptor Potential ◽  
Ros Production ◽  
Caspase 1 ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Background. Pyroptosis, a new form of cell death, which has special morphological characteristics, depends on caspase-1 activation and occupies an important role in inflammatory immune diseases and ischemia-reperfusion injury. ROS is a common activator of NLR/caspase-1. Transient receptor potential melastatin 2 (TRPM2), a selective cation channel, is involved in inflammatory regulation. This study was designed to explore the role of TRPM2 in activating caspase-1 and caspase-1-dependent pyroptosis of mouse BMDMs. Methods. BMDMs isolated from WT and TRPM2−/− mice were treated with LPS and ATP, along with ROS inhibitor (NAC and DPI), caspase-1 inhibitor (Z-YVAD), or not. The activation of caspase-1 was measured by western blot. EtBr and EthD-2 staining were used to assess the incidence of pyroptosis. Results. Compared with WT, the activated caspase-1-P10 was higher and the percentage of EtBr positive cells was also increased in TRPM2−/− group, which were both inhibited by Z-YVAD, NAC, or DPI. ASC oligomerization was increased in TRPM2−/− group. Conclusion. Deletion of TRPM2 can enhance the activation of caspase-1 and pyroptosis, which may be via modulating ROS production, suggesting that TRPM2 plays a critical role in immune adjustment.

Sign in / Sign up

Export Citation Format

Share Document