C1q/tumor necrosis factor-related protein-1 attenuates microglia autophagy and inflammatory response by regulating the Akt/mTOR pathway

Abstract

AimsC1q/tumor necrosis factor-related protein-1 (CTRP1) is a newly identified adiponectin paralog that modulates metabolism and inflammation. However, the cerebral function of CTRP1 remains unknown. This study aimed to determine its role and mechanism in cerebral ischemia and reperfusion injury. Main methodsSerum level of CTRP1 as well as high-sensitivity C reactive protein (hs-CRP) in stroke patients was measured by ELISA assay. The levels of TNF-α, IL-1β, and IL-6 were analyzed using ELISA kits. Quantitative RT-PCR, western blot analysis were conducted to detect indicated genes. Key findingsCTRP1 was significantly upregulated in sera from patients with stroke and positive correlation with hs-CRP. CTRP1 was significantly upregulated in BV2 microglia exposed to oxygen and glucose deprivation and reperfusion (OGD/R). Knockdown of CTRP1 by si-CTRP1 transfection markedly enhanced OGD/R-induced autophagy and accelerated the inflammatory response in BV2 cells, as indicated by increased expression of LC3-II/LC3-I and beclin1, as well as increased concentration of the proinflammatory cytokines TNF-α, IL-1β, and IL-6. However, recombinant CTRP1 or overexpression of CTRP1 attenuated OGD/R-induced autophagy and inflammatory response in BV2 cells. Further study demonstrated that knockdown of CTRP1 decreased, while recombinant CTRP1 increased the phosphorylation of Akt and mTOR in BV2 cells. IGF-1, which activates PI3-kinase and MEK1/2, abolished the promotive effect of si-CTRP1, while inhibition of Akt with A6730 reversed the inhibitory effect of recombinant CTRP1 on BV2 cells autophagy and inflammation response. SignificanceCTRP1 inhibited microglia autophagy and inflammation response by regulating the Akt/mTOR pathway.