MiR-34a Interacts with Cytochrome c and Shapes Stroke Outcomes
Heng Hu, Emily Hone, Edward A. P. Provencher, Samuel A. Sprowls, Imran Farooqi, Deborah Corbin, Saumyendra N. Sarkar, John M. Hollander, Paul R. Lockman, James W. Simpkins, Xuefang Ren
Abstract
Abstract Blood-brain barrier (BBB) dysfunction occurs in cerebrovascular diseases and neurodegenerative disorders such as stroke. Opening of the BBB during a stroke has a negative impact on acute outcomes. We have recently demonstrated that miR-34a regulates the BBB by targeting cytochrome c (CYC) in vitro . To investigate the role of miR-34a in a stroke, we purified primary cerebrovascular endothelial cells (pCECs) from mouse brains following 1 h transient middle cerebral artery occlusion (tMCAO) and measured real-time PCR to detect miR-34a levels. We demonstrate that the miR-34a levels are elevated in pCECs from tMCAO mice at the time point of BBB opening following 1 h tMCAO and reperfusion. Interestingly, knockout of miR-34a significantly reduces BBB permeability, alleviates disruption of tight junctions, and improves stroke outcomes compared to wild-type (WT) controls. CYC is decreased in the ischemic hemispheres and pCECs from WT but not in miR-34a −/− mice following stroke reperfusion. We further confirmed CYC is a target of miR-34a by a dural luciferase reporter gene assay in vitro . Our study provides the first description of miR-34a affecting stroke outcomes and may lead to discovery of new mechanisms and treatments for cerebrovascular and neurodegenerative diseases such as stroke.