Autophagy Inhibition by ATG3 Knockdown Remits Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury and Inflammation in Brain Microvascular Endothelial Cells.

Abstract

Autophagy participates in the development of cerebral ischemia stroke. Autophagy-related 3 (ATG3), an important autophagy regulator, was reported to be upregulated in a rat model of cerebral ischemia/reperfusion (CI/R) injury and an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model. However, the detailed role of ATG3 in CI/R injury remains elusive. An in vitro cellular model was established to mimic CI/R injury by exposing hBMECs and bEnd.3 cells to OGD/R. OGD/R-induced injury were evaluated by cell counting kit-8 (CCK-8), LDH release assay, caspase-3 activity assay and TUNEL assay. Inflammation was assessed by detecting mRNA expression and concentrations of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) using qRT-PCR and ELISA, respectively. The protein levels of ATG3, light chain 3 (LC3)-I, LC3-II, p62, protein kinase B (Akt), and phosphorylated Akt (p-Akt) were determined by western blot analysis. We successfully established an in vitro OGD/R injury model using hBMECs and bEnd.3 cells. ATG3 was time-dependently upregulated and ATG3 knockdown inhibited autophagy in OGD/R-challenged brain microvascular endothelial cells. Moreover, autophagy inhibition by ATG3 interference attenuated OGD/R-induced viability inhibition and increase of LDH release, caspase-3 activity, programmed cell death, and production of IL-1β, IL-6 and TNF-α. Inhibition of autophagy by ATG3 silencing activated the phosphoinositide 3-kinase (PI3K)/Akt pathway in OGD/R-challenged brain microvascular endothelial cells. Furthermore, inhibition of the PI3K/Akt pathway reversed the protective effects of ATG3 silencing on OGD/R-induced injury and inflammation. In conclusion, autophagy inhibition by ATG3 knockdown remitted OGD/R-induced injury and inflammation in brain microvascular endothelial cells via activation of the PI3K/Akt pathway.