Effects of hypoxia and ischemia on microRNAs in the brain.

Hypoxia and ischemia play a major role in the pathogenesis of cerebrovascular diseases such as stroke. However, the protective strategies against hypoxic and ischemic insults are very limited in clinical settings. This has reinforced the need to improve our understanding of the hypoxic and ischemic cascades and explore novel solutions of hypoxic/ ischemic injury. Recent research has identified the crucial role of microRNAs in regulation of gene expression under hypoxic/ischemic conditions. These 19-24 ribonucleotide non-coding RNA molecules function as inhibitory modulators of gene expression, by targeting mRNAs and promoting either RNA degradation or translational repression. They are differentially regulated in the brain as well as other organs under hypoxic and ischemic conditions. Targeting microRNA expression/activity offers a potentially effective way to intervene against hypoxic and ischemic injury. In this review, we highlight recent updates with summary of our recent work, which provides an insight into the roles and mechanisms of microRNA-induced regulation of cellular and molecular processes in response to hypoxic and/or ischemic stress.