GSK3β Inhibition Is the Molecular Pivot That Underlies the Mir-210-Induced Attenuation of Intrinsic Apoptosis Cascade during Hypoxia

Int J Mol Sci. 2022 Aug 19;23(16):9375. doi: 10.3390/ijms23169375.

Abstract

Apoptotic cell death is a deleterious consequence of hypoxia-induced cellular stress. The master hypoxamiR, microRNA-210 (miR-210), is considered the primary driver of the cellular response to hypoxia stress. We have recently demonstrated that miR-210 attenuates hypoxia-induced apoptotic cell death. In this paper, we unveil that the miR-210-induced inhibition of the serine/threonine kinase Glycogen Synthase Kinase 3 beta (GSK3β) in AC-16 cardiomyocytes subjected to hypoxia stress underlies the salutary protective response of miR-210 in mitigating the hypoxia-induced apoptotic cell death. Using transient overexpression vectors to augment miR-210 expression concomitant with the ectopic expression of the constitutive active GSK3β S9A mutant (ca-GSK3β S9A), we exhaustively performed biochemical and molecular assays to determine the status of the hypoxia-induced intrinsic apoptosis cascade. Caspase-3 activity analysis coupled with DNA fragmentation assays cogently demonstrate that the inhibition of GSK3β kinase activity underlies the miR-210-induced attenuation in the hypoxia-driven apoptotic cell death. Further elucidation and delineation of the upstream cellular events unveiled an indispensable role of the inhibition of GSK3β kinase activity in mediating the miR-210-induced mitigation of the hypoxia-driven BAX and BAK insertion into the outer mitochondria membrane (OMM) and the ensuing Cytochrome C release into the cytosol. Our study is the first to unveil that the inhibition of GSK3β kinase activity is indispensable in mediating the miR-210-orchestrated protective cellular response to hypoxia-induced apoptotic cell death.

Keywords: AC-16 cardiomyocytes; BAK; BAX; Cytochrome C; GSK3β; apoptosis; hypoxia; miR-210; mitochondria.

MeSH terms

  • Apoptosis* / genetics
  • Glycogen Synthase Kinase 3 beta* / genetics
  • Glycogen Synthase Kinase 3 beta* / metabolism
  • Humans
  • Hypoxia / genetics
  • MicroRNAs* / genetics
  • MicroRNAs* / metabolism
  • Signal Transduction

Substances

  • MIRN210 microRNA, human
  • MicroRNAs
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta