Dexmedetomidine Postconditioning Alleviates Hypoxia/Reoxygenation Injury in Senescent Myocardial Cells by Regulating lncRNA H19 and m⁶A Modification

Abstract

H19, a long noncoding RNA (lncRNA), reportedly protects myocardial cells (H9c2 cell line) against hypoxia-reoxygenation- (H/R-) induced injury. Dexmedetomidine (Dex) has an important myocardial protective effect, although its function and mechanism in cardiac ischemia/reperfusion (I/R) injury, especially for senile patients, requires further study. RNA N6-methyladenosine (m6A) is the most abundant endogenous RNA modification. However, the effect of Dex postconditioning on RNA m6A modification has rarely been reported. The aim of this study was to evaluate roles of H19 and m6A modification in Dex postconditioning of aged cardiomyocytes. Hydrogen peroxide (H2O2) was used to induce senescence of H9c2 cells. After 6 h of hypoxia, H9c2 cells were exposed to different concentrations of dexmedetomidine (0, 500 nM, 1 μM, and 2 μM) for 6 h. After knockdown or overexpression of H19 and its downstream gene miR-29b-3p and cellular inhibitor of apoptosis protein 1 (cIAP1), Dex postconditioning experiments were performed to examine effects on myocardial cell injury. Global m6A levels after H/R with or without Dex postconditioning were measured with a colorimetric m6A RNA Methylation Quantification Kit. The mechanism by which RNA m6A methylation regulated genes mediating H19 expression was verified by m6A RNA immunoprecipitation (MeRIP), and the function of Dex postconditioning of aged cardiomyocytes was investigated. Dex postconditioning protected against H/R-induced injury of aged myocardial cells through H19/miR-29b-3p/cIAP1, increased methylation of RNA m6A elicited by H/R, and attenuated H/R-induced injury by suppressing expression of the RNA m6A demethylase gene alkB homolog 5 (ALKBH5). In addition, AKLBH5 regulated the expression of H19, and Dex postconditioning attenuated H/R-induced injury via ALKBH5 in aged cardiomyocytes.

Role of N6-methyladenosine Modification in Cardiac Remodeling

“…The m6A modified-H19 has been revealed involving in the development of cardiac diseases. In H 2 O 2 -induced senescence, lncRNA H19 expression decreased and m6A modification increased following H/R, ALKBH5 regulated the expression of H19 by mediating its m6A modification levels ( 73 ).…”

The role of M6A modification in the regulation of tumor-related lncRNAs

“…The combination of METTL3/14 and WATP as a writer, ALKBH5 as an eraser, and YTHDF1 as a reader all influenced the translation of LINC00278 into YY1BM. 130 Zhang et al 131 found that AKLBH5 could regulate the expression of H19, which is a lncRNA, and dexmedetomidine posttreatment could reduce the hypoxia-reoxygenationinduced senile myocardial cell injury by ALKBH5. Highly enriched m 6 A could enhance the RNA stability of LINC00857, and m 6 A-modified LINC00857 upregulation promotes tumorigenesis in pancreatic cancer by regulating the miR-150-5p/E2F3 axis.…”

Role of N6-Methyladenosine RNA Modification in Cardiovascular Disease

“…Additionally, H19 ameliorates ischemia-reperfusion (I/R)-induced myocardial apoptosis or MI-induced myocardial injury by sponging miR-877-3p or miR-22-3p, respectively (91,92). In H9c2 cells with H2O2-induced senescence, H/R enhanced the level of m 6 A methylation and increased the expression of lnc RNA H19 by upregulating ALKBH5 (93). Therefore, the m 6 A modification of H19 is involved in the development of CVD.…”

“…Non-coding RNAs also can regulate m 6 A Micro RNAs such as miR-33a and miR-4429 were found to inhibit METTL3 in the field of tumor studies, indicating that those miRNAs might be as therapeutic agents for CVD (128,129). In addition, lnc RNA H19 has been reported to protect against H2O2induced H9c2 cell apoptosis by up-regulating ALKBH5 (93). Thus, ncRNAs might be used for the regulation of m 6 A and CVD treatment.…”