Chronic hypoxia–induced Cirbp hypermethylation attenuates hypothermic cardioprotection via down-regulation of ubiquinone biosynthesis

2019 ◽  
Vol 11 (489) ◽  
pp. eaat8406 ◽  
Author(s):  
Yiwei Liu ◽  
Junyue Xing ◽  
Yongnan Li ◽  
Qipeng Luo ◽  
Zhanhao Su ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Therapeutic Hypothermia ◽  
Myocardial Injury ◽  
Chronic Hypoxia ◽  
Rna Binding ◽  
Epigenetic Modification ◽  
Neonatal Rat ◽  
Proteomics Analysis ◽  
Rat Cardiomyocytes ◽  
Underlying Mechanisms

Therapeutic hypothermia is commonly used during cardiopulmonary bypass (CPB) to protect the heart against myocardial injury in cardiac surgery. Patients who suffer from chronic hypoxia (CH), such as those with certain heart or lung conditions, are at high risk of severe myocardial injury after cardiac surgery, but the underlying mechanisms are unknown. This study tested whether CH attenuates hypothermic cardioprotection during CPB. Using a rat model of CPB, we found that hypothermic cardioprotection was impaired in CH rats but was preserved in normoxic rats. Cardiac proteomes showed that cold-inducible RNA binding protein (CIRBP) was significantly (P = 0.03) decreased in CH rats during CPB. Methylation analysis of neonatal rat cardiomyocytes under CH and myocardium specimens from patients with CH showed that CH induced hypermethylation of the Cirbp promoter region, resulting in its depression and failure to respond to cold stress. Cirbp-knockout rats showed attenuated hypothermic cardioprotection, whereas Cirbp-transgenic rats showed an enhanced response. Proteomics analysis revealed that the cardiac ubiquinone biosynthesis pathway was down-regulated during CPB in Cirbp-knockout rats, resulting in a significantly (P = 0.01) decreased concentration of ubiquinone (CoQ10). Consequently, cardiac oxidative stress was aggravated and adenosine 5′-triphosphate production was impaired, leading to increased myocardial injury during CPB. CoQ10-supplemented cardioplegic solution improved cardioprotection in rats exposed to CH, but its effect was limited in normoxic rats. Our study suggests that an individualized cardioprotection strategy should be used to fully compensate for the consequences of epigenetic modification of Cirbp in patients with CH who require therapeutic hypothermia.

scholarly journals RBM20 Regulates CaV1.2 Surface Expression by Promoting Exon 9* Inclusion of CACNA1C in Neonatal Rat Cardiomyocytes

2019 ◽  
Vol 20 (22) ◽  
pp. 5591 ◽  
Author(s):  
Morinaga ◽  
Ito ◽  
Niimi ◽  
Maturana
Keyword(s):  
Alternative Splicing ◽  
Heart Development ◽  
Rna Binding ◽  
Surface Expression ◽  
Neonatal Rat ◽  
Sequencing Analysis ◽  
Rat Cardiomyocytes ◽  
Neonatal Rat Cardiomyocytes ◽  
Exon 9 ◽  
Sirna Knockdown

The CACNA1C gene encodes for the CaV1.2 protein, which is the pore subunit of cardiac l-type voltage-gated calcium (Ca2+) channels (l-channels). Through alternative splicing, CACNA1C encodes for various CaV1.2 isoforms with different electrophysiological properties. Splice variants of CaV1.2 are differentially expressed during heart development or pathologies. The molecular mechanisms of CACNA1C alternative splicing still remain incompletely understood. RNA sequencing analysis has suggested that CACNA1C is a potential target of the splicing factor RNA-binding protein motif 20 (RBM20). Here, we aimed at elucidating the role of RBM20 in the regulation of CACNA1C alternative splicing. We found that in neonatal rat cardiomyocytes (NRCMs), RBM20 overexpression promoted the inclusion of CACNA1C’s exon 9*, whereas the skipping of exon 9* occurred upon RBM20 siRNA knockdown. The splicing of other known alternative exons was not altered by RBM20. RNA immunoprecipitation suggested that RBM20 binds to introns flanking exon 9*. Functionally, in NRCMs, RBM20 overexpression decreased l-type Ca2+ currents, whereas RBM20 siRNA knockdown increased l-type Ca2+ currents. Finally, we found that RBM20 overexpression reduced CaV1.2 membrane surface expression in NRCMs. Taken together, our results suggest that RBM20 specifically regulates the inclusion of exon 9* in CACNA1C mRNA, resulting in reduced cell-surface membrane expression of l-channels in cardiomyocytes.

scholarly journals METTL3 improves cardiomyocyte proliferation upon myocardial infarction via upregulating miR-17-3p in a DGCR8-dependent manner

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Kun Zhao ◽  
Chuanxi Yang ◽  
Jing Zhang ◽  
Wei Sun ◽  
Bin Zhou ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Rna Binding ◽  
Underlying Mechanism ◽  
Neonatal Rat ◽  
Dependent Manner ◽  
Cardiomyocyte Proliferation ◽  
Rat Cardiomyocytes

AbstractMyocardial infarction (MI), one of the most severe types of heart attack, exerts a strong negative effect on heart muscle by causing a massive and rapid loss of cardiomyocytes. However, the existing therapies do little to improve cardiac regeneration. Due to the role of methyltransferase-like 3 (METTL3) in the physiological proliferation of cardiomyocytes, we aimed to determine whether METTL3 could also promote cardiomyocyte proliferation under pathological conditions and to elucidate the underlying mechanism. The effects of METTL3 on cardiomyocyte proliferation and apoptosis were investigated in an in vivo rat model of MI and in an in vitro model of neonatal rat cardiomyocytes (NRCMs) exposed to hypoxia. We found that METTL3 expression was downregulated in hypoxia-exposed NRCMs and MI-induced rats. Furthermore, METTL3 pretreatment enhanced cardiomyocyte proliferation and inhibited cardiomyocyte apoptosis under hypoxic or MI conditions, and silencing METTL3 had the opposite effects. Additionally, METTL3 overexpression upregulated miR-17-3p expression. The miR-17-3p agomir mimicked the pro-proliferative and antiapoptotic effects of METTL3 in hypoxia-exposed cells or rats with MI, while the miR-17-3p antagomir blocked these effects. Additionally, pretreatment with the RNA-binding protein DGCR8 also hampered the protective role of METTL3 in hypoxia-exposed cells. Overall, the current study indicated that METTL3 could improve cardiomyocyte proliferation and subsequently ameliorate MI in rats by upregulating proliferation-related miR-17-3p in a DGCR8-dependent pri-miRNA-processing manner.

scholarly journals A20 (TNFAIP3) alleviates viral myocarditis through ADAR1/miR-1a-3p-dependent regulation

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Bin Li ◽  
Xing Xie
Keyword(s):  
Creatine Kinase ◽  
Rna Binding ◽  
Viral Myocarditis ◽  
Neonatal Rat ◽  
Coxsackie Virus ◽  
Luciferase Reporter ◽  
Cell Culture Supernatant ◽  
Tunel Staining ◽  
Rat Cardiomyocytes ◽  
Cellular Models

Abstract Objective To investigate the effect of A20 and how A20 is regulated in viral myocarditis (VMC). Methods BABL/C mice, primary neonatal rat cardiomyocytes and H9c2 cells were infected with Coxsackie virus B3 (CVB3) to establish animal and cellular models of VMC. H&E staining revealed the pathologic condition of myocardium. ELISA measured the serum levels of creatine kinase, creatine kinase isoenzyme and cardiac troponin I. The effects of A20, miR-1a-3p and ADAR1 were investigated using gain and loss of function approaches. ELISA measured the levels of IL-6, IL-18 and TNF-α in serum or cell culture supernatant. TUNEL staining and flow cytometry assessed the apoptosis of myocardium and cardiomyocytes, respectively. RNA-binding protein immunoprecipitation and dual-luciferase reporter assays verified the binding between A20 and miR-1a-3p. Co-immunoprecipitation assay verified the binding between ADAR1 and Dicer. Results A20 was underexpressed and miR-1a-3p was overexpressed in the myocardium of VMC mice as well as in CVB3-infected cardiomyocytes. Overexpression of A20 suppressed cardiomyocyte inflammation and apoptosis in vivo and in vitro. miR-1a-3p promoted CVB3-induced inflammation and apoptosis in cardiomyocytes by binding to A20. The expression of miR-1a-3p was regulated by ADAR1. ADAR1 promoted the slicing of miR-1a-3p precursor by binding to Dicer. Conclusion A20, regulated by ADAR1/miR-1a-3p, suppresses inflammation and cardiomyocyte apoptosis in VMC.

scholarly journals Release mechanisms of major DAMPs

APOPTOSIS ◽  
2021 ◽  
Vol 26 (3-4) ◽  
pp. 152-162
Author(s):  
Atsushi Murao ◽  
Monowar Aziz ◽  
Haichao Wang ◽  
Max Brenner ◽  
Ping Wang
Keyword(s):  
Rna Binding ◽  
High Mobility ◽  
Live Cells ◽  
Membrane Channel ◽  
Membrane Rupture ◽  
Underlying Mechanisms ◽  
Shock Proteins ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Secretory Lysosomes

AbstractDamage-associated molecular patterns (DAMPs) are endogenous molecules which foment inflammation and are associated with disorders in sepsis and cancer. Thus, therapeutically targeting DAMPs has potential to provide novel and effective treatments. When establishing anti-DAMP strategies, it is important not only to focus on the DAMPs as inflammatory mediators but also to take into account the underlying mechanisms of their release from cells and tissues. DAMPs can be released passively by membrane rupture due to necrosis/necroptosis, although the mechanisms of release appear to differ between the DAMPs. Other types of cell death, such as apoptosis, pyroptosis, ferroptosis and NETosis, can also contribute to DAMP release. In addition, some DAMPs can be exported actively from live cells by exocytosis of secretory lysosomes or exosomes, ectosomes, and activation of cell membrane channel pores. Here we review the shared and DAMP-specific mechanisms reported in the literature for high mobility group box 1, ATP, extracellular cold-inducible RNA-binding protein, histones, heat shock proteins, extracellular RNAs and cell-free DNA.

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