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

Abstract

Background Anesthetic cardioprotection reduces myocardial infarct size following ischemia-reperfusion injury. Currently, the role of microRNA in this process remains unknown. MicroRNAs are short, non-coding nucleotide sequences that negatively regulate gene expression through degradation or suppression of messenger RNA. In this study, we uncovered the functional role of microRNA-21 (miR-21) upregulation 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 upregulation 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 downregulation of programmed cell death protein 4 (PDCD4) messenger RNA (n = 3, 82.0 ± 4.9% of control group). This protective effect was confirmed through knockdown of miR-21 and PDCD4 in vitro. Additionally, the protective effect of isoflurane was abolished in miR-21 knockout mice in vivo, with no significant decrease in infarct size compared to non-exposed controls (n = 8, 62.3 ± 4.6% and 56.2 ± 3.2%). Conclusions We demonstrate for the first time that isoflurane mediates protection of cardiomyocytes against oxidative stress via a miR-21/PDCD4 pathway. These results reveal a novel mechanism by which the damage done by ischemia-reperfusion injury may be decreased.

MicroRNA-21 Mediates Isoflurane-induced Cardioprotection against Ischemia–Reperfusion Injury via Akt/Nitric Oxide Synthase/Mitochondrial Permeability Transition Pore Pathway

“…Recently, we have indicated that PDCD4 is a down-stream target of miR-21 in ISO-induced protection of cardiomyocytes. 20 Thus, ISO-induced up-regulation of miR-21 may alter the expression of multiple gene targets.…”

“…In rat hearts or neonatal rat cardiomyocytes, our array analyses of microRNAs indicate that ISO up-regulated 11 out of 87 microRNAs studied, including miR-21, microRNA-210, and microRNA-30 family. 20 It is likely that multiple microRNAs are involved in the cardioprotective effect of ISO. However, miR-21 plays an important role in protection of cardiomyocytes against hypoxia/reoxygenation injury.…”

“…12 Recently, miR-21 is found to involve the ISO-induced protection of cardiomyocytes against hypoxia/reoxygenation injury. 20 However, how miR-21 contributes to ISO-induced protection against myocardial I/R injury remains elusive. The aim of this study was to examine the role of miR-21 in ISO-induced protection against acute myocardial I/R injury using miR-21 gene knockout (KO) mice.…”

MicroRNA-21 regulates peroxisome proliferator–activated receptor alpha, a molecular mechanism of cardiac pathology in Cardiorenal Syndrome Type 4

“…59 H9C2 cardiac myoblast cells (ATCC) were transfected with anti-scr or anti–miR-21-5p (40 nM, Exiqon, Vedbaek, Denmark), as previously described. 60 After 48 hours, cells were treated with insulin-like growth factor-1 (50 ng/ml; StemRD, Burlingame, CA) or saline vehicle for an additional 24 hours ( N = 3 per group). Cells were fixed and imaged.…”

“…Neonatal rat cardiomyocytes were transfected with 20 nM pre-miR-21-5p or scr control ( N = 3 per group) (ThermoFisher) as previously described 60 and collected 48 hours later. Tissue and cell material were processed for Western blot analysis as previously described, with quantification of Coomassie staining used as to normalize protein loaded.…”