Cytoprotective Effect of the UCP2-SIRT3 Signaling Pathway by Decreasing Mitochondrial Oxidative Stress on Cerebral Ischemia-Reperfusion Injury

Abstract

Recovered blood supply after cerebral ischemia for a certain period of time fails to restore brain function, with more severe dysfunctional problems developing, called cerebral ischemia-reperfusion injury (CIR). CIR involves several extremely complex pathophysiological processes in which the interactions between key factors at various stages have not been fully elucidated. Mitochondrial dysfunction is one of the most important mechanisms of CIR. The mitochondrial deacetylase, sirtuin 3 (SIRT3), can inhibit mitochondrial oxidative stress by deacetylation, to maintain mitochondrial stability. Uncoupling protein 2 (UCP2) regulates ATP (Adenosine triphosphate) and reactive oxygen species production by affecting the mitochondrial respiratory chain, which may play a protective role in CIR. Finally, we propose that UCP2 regulates the activity of SIRT3 through sensing the energy level and, in turn, maintaining the mitochondrial steady state, which demonstrates a cytoprotective effect on CIR.

Keywords: cerebral ischemia/reperfusion injury; mitochondria; oxidative stress; peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α); sirtuin 3 (SIRT3); uncoupling protein 2 (UCP2).

Figure 1

Proposed model for UCP2-SIRT3 (uncoupling protein 2-sirtuin 3) signaling pathway on cerebral ischemia–reperfusion injury. (A) Mitochondrial dysfunction caused by cerebral ischemia–reperfusion injury leads cells to death. (B) Protective mechanism of UCP2-SIRT3 signaling pathway on mitochondria damage.