Protective role of ABCA1 in ischemic preconditioning is mediated by downregulation of miR-33-5p and miR-135-5p

Sci Rep. 2021 Jun 15;11(1):12511. doi: 10.1038/s41598-021-91982-x.

Abstract

Ischemic preconditioning (IPC) significantly reduces ischemia-reperfusion injury in the brain by inducing ischemic tolerance. Although emerging evidence suggests that microRNAs (miRNAs) contribute to the pathogenesis of brain ischemia and IPC-induced neuroprotection, the role of miRNAs and their underlying mechanisms are still unclear. IPC was induced in male C57BL/6 mice by brief bilateral common carotid artery occlusion. After 24 h, mice underwent transient middle cerebral artery occlusion followed by 3 h of reperfusion. Expression levels of messenger RNAs (mRNAs) and proteins were examined in the ipsilateral cortex, and mimics and inhibitors of selective miRNAs were transfected into Neuro-2a cells before oxygen-glucose deprivation (OGD). Post-IPC miRNA expression profiling identified neuroprotection-associated changes in miRNA expression in the ipsilateral cortex after ischemic stroke. Among them, miR-33-5p and miR-135b-5p were significantly downregulated by IPC. Inhibition of miR-33-5p and miR-135b-5p expression protected Neuro-2a cells from OGD-induced apoptosis. Inhibition of these two miRNAs significantly increased mRNA and protein levels of ATP-binding cassette subfamily A member 1 (ABCA1), and a binding assay showed that these two miRNAs showed specificity for Abca1 mRNA. Overexpression of ABCA1 decreased the Bax/Bcl2 mRNA ratio and activation of caspase-9 and caspase-3, whereas knockdown of ABCA1 expression increased the Bax/Bcl2 mRNA ratio and the percentage of Neuro-2a cells with a loss of mitochondrial membrane potential after OGD-treatment. In conclusion, ABCA1 expression is regulated by miR-33-5p and miR-135b-5p. Increased ABCA1 expression following IPC exerts a protective influence against cerebral ischemia via suppression of a mitochondria-dependent apoptosis pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter 1 / genetics*
  • Animals
  • Apoptosis / genetics
  • Brain / metabolism
  • Brain / pathology
  • Brain Ischemia / genetics*
  • Brain Ischemia / pathology
  • Disease Models, Animal
  • Gene Expression Regulation / genetics
  • Humans
  • Infarction, Middle Cerebral Artery / genetics
  • Infarction, Middle Cerebral Artery / pathology
  • Ischemic Preconditioning / methods
  • Mice
  • MicroRNAs / genetics*
  • Neuroprotection / genetics
  • Oxygen / metabolism
  • Reperfusion Injury / genetics*
  • Reperfusion Injury / pathology

Substances

  • ABCA1 protein, mouse
  • ATP Binding Cassette Transporter 1
  • MicroRNAs
  • Mirn135 microRNA, mouse
  • Mirn33 microRNA, mouse
  • Oxygen