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Yu R, Wang Y, Zhu J, Yang G. H 2S-mediated blockage of protein acetylation and oxidative stress attenuates lipid overload-induced cardiac senescence. Arch Physiol Biochem 2024; 130:96-109. [PMID: 34511001 DOI: 10.1080/13813455.2021.1976209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/30/2021] [Indexed: 10/20/2022]
Abstract
Hydrogen sulphide (H2S), a newly identified gasotransmitter, can be endogenously produced by cystathionine gamma-lyase (CSE) in the cardiovascular system. This study investigated the role of the CSE/H2S system on lipid overload-induced lipotoxicity and cardiac senescence. Lipid overload in rat cardiomyocyte cells (H9C2) promoted intracellular accumulation of lipid, oxidative stress, mitochondrial dysfunctions, lipid peroxidation and inhibited cell viability, all of which could be reversed by exogenously applied H2S. Further data revealed that H2S protected H9C2 cells from lipid overload-induced senescence by altering the expressions of lipid metabolism-related genes and inhibiting cellular acetyl-CoA and global protein acetylation. Enhancement of protein acetylation abolished the protective role of H2S on cardiac senescence. In vivo, knockout of the CSE gene strengthened cardiac lipid accumulation, protein acetylation, and cellular ageing in high fat diet-fed mice. Taken together, the CSE/H2S system is capable of maintaining lipid homeostasis and cellular senescence in heart cells under lipid overload.
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Affiliation(s)
- Ruihuan Yu
- School of Biological, Chemical & Forensic Sciences, Laurentian University, Sudbury, Canada
- Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada
| | - Yuehong Wang
- School of Biological, Chemical & Forensic Sciences, Laurentian University, Sudbury, Canada
- Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada
| | - Jiechun Zhu
- School of Biological, Chemical & Forensic Sciences, Laurentian University, Sudbury, Canada
- Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada
| | - Guangdong Yang
- School of Biological, Chemical & Forensic Sciences, Laurentian University, Sudbury, Canada
- Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada
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2
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Tian G, Zhou J, Quan Y, Kong Q, Li J, Xin Y, Wu W, Tang X, Liu X. Voltage-dependent anion channel 1 (VDAC1) overexpression alleviates cardiac fibroblast activation in cardiac fibrosis via regulating fatty acid metabolism. Redox Biol 2023; 67:102907. [PMID: 37797372 PMCID: PMC10622884 DOI: 10.1016/j.redox.2023.102907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/07/2023] Open
Abstract
Cardiac fibrosis is characterized by the excessive deposition of extracellular matrix in the myocardium with cardiac fibroblast activation, leading to chronic cardiac remodeling and dysfunction. However, little is known about metabolic alterations in fibroblasts during cardiac fibrosis, and there is a lack of pharmaceutical treatments that target metabolic dysregulation. Here, we provided evidence that fatty acid β-oxidation (FAO) dysregulation contributes to fibroblast activation and cardiac fibrosis. With transcriptome, metabolome, and functional assays, we demonstrated that FAO was downregulated during fibroblast activation and cardiac fibrosis, and that perturbation of FAO reversely affected the fibroblast-to-myofibroblast transition. The decrease in FAO may be attributed to reduced long-chain fatty acid (LCFA) uptake. Voltage-dependent anion channel 1 (VDAC1), the main gatekeeper of the outer mitochondrial membrane (OMM), serves as the transporter of LCFA into the mitochondria for further utilization and has been shown to be decreased in myofibroblasts. In vitro, the addition of exogenous VDAC1 was shown to ameliorate cardiac fibroblast activation initiated by transforming growth factor beta 1 (TGF-β1) stimuli, and silencing of VDAC1 displayed the opposite effect. A mechanistic study revealed that VDAC1 exerts a protective effect by regulating LCFA uptake into the mitochondria, which is impaired by an inhibitor of carnitine palmitoyltransferase 1A. In vivo, AAV9-mediated overexpression of VDAC1 in myofibroblasts significantly alleviated transverse aortic constriction (TAC)-induced cardiac fibrosis and rescued cardiac function in mice. Finally, we treated mice with the VDAC1-derived R-Tf-D-LP4 peptide, and the results showed that R-Tf-D-LP4 prevented TAC-induced cardiac fibrosis and dysfunction in mice. In conclusion, this study provides evidence that VDAC1 maintains FAO metabolism in cardiac fibroblasts to repress fibroblast activation and cardiac fibrosis and suggests that the VDAC1 peptide is a promising drug for rescuing fibroblast metabolism and repressing cardiac fibrosis.
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Affiliation(s)
- Geer Tian
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Junteng Zhou
- Health Management Center, General Practice Medical Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yue Quan
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Qihang Kong
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Junli Li
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Yanguo Xin
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Wenchao Wu
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Xiaoqiang Tang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, No.17 People's South Road, Chengdu, Sichuan, 610041, China; National Health Commission Key Laboratory of Chronobiology, Sichuan University, No.17 People's South Road, Chengdu, Sichuan, 610041, China; Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, No.17 People's South Road, Chengdu, Sichuan, 610041, China.
| | - Xiaojing Liu
- Department of Cardiology and Laboratory of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China.
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Kar A, Gupta S, Matilal A, Kumar D, Sarkar S. Nanotherapeutics for the Myocardium: A Potential Alternative for Treating Cardiac Diseases. J Cardiovasc Pharmacol 2023; 82:180-188. [PMID: 37341530 DOI: 10.1097/fjc.0000000000001444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 06/03/2023] [Indexed: 06/22/2023]
Abstract
ABSTRACT Cardiovascular diseases (CVDs) are the foremost cause of morbidity and mortality worldwide. Current clinical interventions include invasive approaches for progressed conditions and pharmacological assistance for initial stages, which has systemic side effects. Preventive, curative, diagnostic, and theranostic (therapeutic + diagnostic) approaches till date are not very useful in combating the ongoing CVD epidemic, which demands a promising efficient alternative approach. To combat the growing CVD outbreak globally, the ideal strategy is to make the therapeutic intervention least invasive and direct to the heart to reduce the bystander effects on other organs and increase the bioavailability of the therapeutics to the myocardium. The application of nanoscience and nanoparticle-mediated approaches have gained a lot of momentum because of their efficient passive and active myocardium targeting capability owing to their improved specificity and controlled release. This review provides extensive insight into the various types of nanoparticles available for CVDs, their mechanisms of targeting (eg, direct or indirect), and the utmost need for further development of bench-to-bedside cardiac tissue-based nanomedicines. Furthermore, the review aims to summarize the different ideas and methods of nanoparticle-mediated therapeutic approaches to the myocardium till date with present clinical trials and future perspectives. This review also reflects the potential of such nanoparticle-mediated tissue-targeted therapies to contribute to the sustainable development goals of good health and well-being.
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Affiliation(s)
- Abhik Kar
- Department of Zoology, University of Calcutta, Kolkata, West Bengal, India
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Banik A, Datta Chaudhuri R, Vashishtha S, Gupta S, Kar A, Bandyopadhyay A, Kundu B, Sarkar S. Deoxyelephantopin-a novel PPARγ agonist regresses pressure overload-induced cardiac fibrosis via IL-6/STAT-3 pathway in crosstalk with PKCδ. Eur J Pharmacol 2023:175841. [PMID: 37329972 DOI: 10.1016/j.ejphar.2023.175841] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/03/2023] [Accepted: 06/08/2023] [Indexed: 06/19/2023]
Abstract
Pathological cardiac hypertrophy is associated with ventricular fibrosis leading to heart failure. The use of thiazolidinediones as Peroxisome Proliferator-Activated Receptor-gamma (PPARγ)-modulating anti-hypertrophic therapeutics has been restricted due to major side-effects. The present study aims to evaluate the anti-fibrotic potential of a novel PPARγ agonist, deoxyelephantopin (DEP) in cardiac hypertrophy. AngiotensinII treatment in vitro and renal artery ligation in vivo was performed to mimic pressure overload-induced cardiac hypertrophy. Myocardial fibrosis was evaluated by Masson's trichrome staining and hydroxyproline assay. Our results showed that DEP treatment significantly improves the echocardiographic parameters by ameliorating ventricular fibrosis without any bystander damage to other major organs. Following molecular docking, all atomistic molecular dynamics simulation, reverse transcription-polymerase chain reaction and immunoblot analyses, we established DEP as a PPARγ agonist stably interacting with the ligand-binding domain of PPARγ. DEP specifically downregulated the Signal Transducer and Activator of Transcription (STAT)-3-mediated collagen gene expression in a PPARγ-dependent manner, as confirmed by PPARγ silencing and site-directed mutagenesis of DEP-interacting PPARγ residues. Although DEP impaired STAT-3 activation, it did not have any effect on the upstream Interleukin (IL)-6 level implying possible crosstalk of the IL-6/STAT-3 axis with other signaling mediators. Mechanistically, DEP increased the binding of PPARγ with Protein Kinase C-delta (PKCδ) which impeded the membrane translocation and activation of PKCδ, downregulating STAT-3 phosphorylation and resultant fibrosis. This study, therefore, for the first time demonstrates DEP as a novel cardioprotective PPARγ agonist. The therapeutic potential of DEP as an anti-fibrotic remedy can be exploited against hypertrophic heart failure in the future.
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Affiliation(s)
- Anirban Banik
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Ratul Datta Chaudhuri
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Shubham Vashishtha
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Soumyadeep Gupta
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Abhik Kar
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | | | - Bishwajit Kundu
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Sagartirtha Sarkar
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
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5
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Huang Z, Luo R, Yang L, Chen H, Zhang X, Han J, Wang H, Zhou Z, Wang Z, Shao L. CPT1A-Mediated Fatty Acid Oxidation Promotes Precursor Osteoclast Fusion in Rheumatoid Arthritis. Front Immunol 2022; 13:838664. [PMID: 35273614 PMCID: PMC8902079 DOI: 10.3389/fimmu.2022.838664] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 02/01/2022] [Indexed: 12/29/2022] Open
Abstract
The overproduction of osteoclasts, leading to bone destruction in patients with rheumatoid arthritis (RA), is well established. However, little is known about the metabolic dysfunction of osteoclast precursors (OCPs) in RA. Herein, we show that increasing fatty acid oxidation (FAO) induces OCP fusion. Carnitine palmitoyltransferase IA (CPT1A), which is important for carnitine transportation and is involved in FAO in the mitochondria, is upregulated in RA patients. This metabolic change further increases the expression of clathrin heavy chain (CLTC) and clathrin light chain A (CLTA) by enhancing the binding of the transcription factor CCAAT/enhancer binding protein β (C/EBPβ) to the promoters of CLTA and CLTC. This drives clathrin-dependent endocytosis pathway, which attenuates fusion receptors in the cellular membrane and contributes to increased podosome structure formation. This study reveals a new mechanism through which FAO metabolism participates in joint destruction in RA and provides a novel therapeutic direction for the development of drugs against bone destruction in patients with RA.
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Affiliation(s)
- Zhaoyang Huang
- The Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Rong Luo
- The Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Liu Yang
- Department of Rheumatology, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Haiqi Chen
- The Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xinyao Zhang
- Department of Urology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jiawen Han
- The Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hongxia Wang
- Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhongyang Zhou
- The Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zhao Wang
- Department of Orthopaedics, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Lan Shao
- The Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
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Wang L, Wang P, Xu S, Li Z, Duan DD, Ye J, Li J, Ding Y, Zhang W, Lu J, Liu P. The cross-talk between PARylation and SUMOylation in C/EBPβ at K134 site participates in pathological cardiac hypertrophy. Int J Biol Sci 2022; 18:783-799. [PMID: 35002525 PMCID: PMC8741850 DOI: 10.7150/ijbs.65211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/13/2021] [Indexed: 12/23/2022] Open
Abstract
Poly(ADP-ribosyl)ation (PARylation) and SUMO modification (SUMOylation) are novel post-translational modifications (PTMs) mainly induced by PARP1 and SUMO1. Growing evidence has revealed that C/EBPβ plays multiple roles in biological processes and participates in cardiovascular diseases. However, the cross-talk between C/EBPβ PARylation and SUMOylation during cardiovascular diseases is unknown. This study aims to investigate the effects of C/EBPβ PTMs on cardiac hypertrophy and its underlying mechanism. Abdominal aortic constriction (AAC) and phenylephrine (PE) were conducted to induce cardiac hypertrophy. Intramyocardial delivery of recombinant adenovirus (Ad-PARP1) was taken to induce PARP1 overexpression. In this study, we found C/EBPβ participates in PARP1-induced cardiac hypertrophy. C/EBPβ K134 residue could be both PARylated and SUMOylated individually by PARP1 and SUMO1. Moreover, the accumulation of PARylation on C/EBPβ at K134 site exhibits downregulation of C/EBPβ SUMOylation at the same site. Importantly, C/EBPβ K134 site SUMOylation could decrease C/EBPβ protein stability and participates in PARP1-induced cardiac hypertrophy. Taken together, these findings highlight the importance of the cross-talk between C/EBPβ PTMs at K134 site in determining its protein level and function, suggesting that multi-target pharmacological strategies inhibiting PARP1 and activating C/EBPβ SUMOylation would be potential for treating pathological cardiac hypertrophy.
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Affiliation(s)
- Luping Wang
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China.,Laboratory of Hematopathology & Drug Discovery, School of Medicine, South China University of Technology, Guangdong, China
| | - Panxia Wang
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China
| | - Suowen Xu
- Department of Endocrinology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, China
| | - Zhuoming Li
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China
| | - Dayue Darrel Duan
- Center for Phenomics of Traditional Chinese Medicine/the Affiliated Hospital of Traditional Chinese Medicine, Southwest Medical University, Sichuan, China
| | - Jiantao Ye
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China
| | - Jingyan Li
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China
| | - Yanqing Ding
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China
| | - Wenqing Zhang
- Laboratory of Hematopathology & Drug Discovery, School of Medicine, South China University of Technology, Guangdong, China
| | - Jing Lu
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China
| | - Peiqing Liu
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China.,National and Local United Engineering Lab of Druggability and New Drugs Evaluation, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangdong, China.,School of Pharmacy, Jinan University, 601 Huangpu Avenue West, Guangdong, China
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7
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Paul S, Bravo Vázquez LA, Uribe SP, Manzanero Cárdenas LA, Ruíz Aguilar MF, Chakraborty S, Sharma A. Roles of microRNAs in carbohydrate and lipid metabolism disorders and their therapeutic potential. Biochimie 2021; 187:83-93. [PMID: 34082043 DOI: 10.1016/j.biochi.2021.05.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/19/2021] [Accepted: 05/25/2021] [Indexed: 02/07/2023]
Abstract
MicroRNAs (miRNAs) are small (∼21 nucleotides), endogenous, non-coding RNA molecules implicated in the post-transcriptional gene regulation performed through target mRNA cleavage or translational inhibition. In recent years, several investigations have demonstrated that miRNAs are involved in regulating both carbohydrate and lipid homeostasis in humans and other organisms. Moreover, it has been observed that the dysregulation of these metabolism-related miRNAs leads to the development of several metabolic disorders, such as type 2 diabetes, obesity, nonalcoholic fatty liver, insulin resistance, and hyperlipidemia. Hence, in this current review, with the aim to impulse the research arena of the micro-transcriptome implications in vital metabolic pathways as well as to highlight the remarkable potential of miRNAs as therapeutic targets for metabolic disorders in humans, we provide an overview of the regulatory roles of metabolism-associated miRNAs in humans and murine models.
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Affiliation(s)
- Sujay Paul
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Av. Epigmenio Gonzalez, No. 500 Fracc, San Pablo, CP 76130, Querétaro, Mexico.
| | - Luis Alberto Bravo Vázquez
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Av. Epigmenio Gonzalez, No. 500 Fracc, San Pablo, CP 76130, Querétaro, Mexico
| | - Samantha Pérez Uribe
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Av. Epigmenio Gonzalez, No. 500 Fracc, San Pablo, CP 76130, Querétaro, Mexico
| | - Luis Aarón Manzanero Cárdenas
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Ciudad de Mexico, Calle del Puente, No. 222 Col. Ejidos de Huipulco, Tlalpan, CP 14380, Mexico City, Mexico
| | - María Fernanda Ruíz Aguilar
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Ciudad de Mexico, Calle del Puente, No. 222 Col. Ejidos de Huipulco, Tlalpan, CP 14380, Mexico City, Mexico
| | - Samik Chakraborty
- Division of Nephrology, Boston Children's Hospital, Harvard Medical School, MA, 02115, USA
| | - Ashutosh Sharma
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Av. Epigmenio Gonzalez, No. 500 Fracc, San Pablo, CP 76130, Querétaro, Mexico.
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Datta Chaudhuri R, Banerjee D, Banik A, Sarkar S. Severity and duration of hypoxic stress differentially regulates HIF-1α-mediated cardiomyocyte apoptotic signaling milieu during myocardial infarction. Arch Biochem Biophys 2020; 690:108430. [PMID: 32473132 DOI: 10.1016/j.abb.2020.108430] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/30/2020] [Accepted: 05/21/2020] [Indexed: 01/04/2023]
Abstract
BACKGROUND The severity and duration of hypoxia is known to determine apoptotic fate in heart; however, its implication during myocardial infarction (MI) remains unaddressed. Therefore the aim of the study was to determine apoptotic regulation in cardiomyocytes under varied hypoxic intensity and duration and to unravel the role of HIF-1α in such modulation. METHODS Treatment of cardiomyocytes to varied hypoxic intensity and duration was carried out in vitro, which was mimicked in vivo by dose-dependent Isoproterenol hydrochloride treatment for varied time-points. Myocardium-targeted HIF-1α knockdown in vivo was performed to decipher its role in cardiomyocyte apoptosis under varied stress. Signaling intermediates were analyzed by RT-PCR, immunoblotting and co-immunoprecipitation. DCFDA-based ROS assay, Griess assay for NO release and biochemical assays for estimating caspase activity were performed. RESULTS Severe stress resulted in cardiomyocyte apoptosis in both shorter and longer time-points. Moderate stress, on the other hand, induced apoptosis only in the shorter time-point which was downregulated in the longer time-point. ROS activity was upregulated under severe hypoxic stress for both time-points and only in the early time-point under moderate hypoxia. Increased ROS accumulation activated ERK-1/2 which stabilized nuclear HIF-1α, promoting bnip3-mediated apoptosis. Stable HSP90-IRE-1 association in such cells caused elevated endoplasmic reticulum stress-related caspase-12 activity. Sustained moderate hypoxia caused decline in ROS activity, but upregulated NFκB-dependent NO generation. NO-stabilized HIF-1α was predominantly cytosolic, since low ROS levels downregulated ERK-1/2 activity, thereby suppressing bnip3 expression. Cytosolic HIF-1α in such cells sequestered HSP90 from IRE-1, downregulating caspase-12 activity due to proteasomal degradation of IRE-1. Accordingly, myocardium-specific in vivo silencing of HIF-1α was beneficial at both time-points under severe stress as also for lesser duration of moderate stress. However, silencing of HIF-1α aggravated apoptotic injury during sustained moderate stress. CONCLUSION ROS-mediated HIF-1α stabilization promotes cardiomyocyte apoptosis on one hand while NO-mediated stabilization of HIF-1α disrupts apoptosis depending upon the severity and duration of hypoxia. Therefore the outcome of modulation of cardiac HIF-1α activity is regulated by both the severity and duration of ischemic stress.
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Affiliation(s)
- Ratul Datta Chaudhuri
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
| | - Durba Banerjee
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
| | - Anirban Banik
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
| | - Sagartirtha Sarkar
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
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