MicroRNA-338 inhibition protects against focal cerebral ischemia and preserves mitochondrial function in vitro in astrocytes and neurons via COX4I1.

Abstract

Brain-enriched microRNA-338 (miR-338) is known to play a central role in brain mitochondrial function, however the role of miR-338 in stroke injury remains unknown. This study investigated the role of miR-338 in injury from transient focal cerebral ischemia in mice, and in cell survival and mitochondrial function after in vitro ischemia in astrocyte and neuronal cultures. Pre-treatment of mice with intracerebroventricular injection of miR-338 antagomir 24 h prior to 1 h of middle cerebral artery occlusion (MCAO) significantly reduced infarct size and improved neurological score at both 24 h and 7d after injury. Levels of the miR-338 target cytochrome-c oxidase subunit 4I1 (COX4I1), which plays an essential role in maintaining brain mitochondrial ATP production, were increased in miR-338 antagomir-treated mice. Mouse primary astrocyte cell cultures subjected to glucose deprivation exhibited increased cell survival when pre-treated with miR-338 inhibitor, and greater cell death with miR-338 mimic. Decreased miR-338 levels were associated with increased ATP production, augmented cytochrome c oxidative (CcO) activity and preservation of COX4I1. In vitro protection with miR-338 inhibitor was blocked by concurrent knockdown of COX4I1 with small interfering RNA. Parallel studies in mouse neuronal N2a cultures resulted in preserved ATP content and CcO activity with miR-338 inhibition, indicating a shared miR-338-dependent response to ischemic stress between brain cell types. These results suggest that miR-338 inhibition and/or COX4I1-targeted therapies may be novel clinical strategies to protect against stroke injury via preservation of mitochondrial function in multiple cell types.

• Authors: Le Li, Ludmila Voloboueva, Brian B Griffiths, Lijun Xu, Rona G Giffard, Creed M Stary
• Journal: Mitochondrion (Mitochondrion) Vol. 59 Pg. 105-112 (07 2021) ISSN: 1872-8278 [Electronic] Netherlands
• PMID: 33933660 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Chemical References

• MicroRNAs
• Mirn338 microRNA, mouse
• Cox4i1 protein, mouse
• Electron Transport Complex IV

Topics

• Animals
• Astrocytes (chemistry, cytology)
• Brain Ischemia (etiology, genetics, metabolism)
• Cell Survival
• Cells, Cultured
• Disease Models, Animal
• Electron Transport Complex IV (genetics)
• Gene Expression Regulation
• Male
• Mice
• Mice, Inbred C57BL
• MicroRNAs (genetics)
• Mitochondria (metabolism)
• Neurons (chemistry, cytology)
• Primary Cell Culture