Protease-activated receptor-2 promotes kidney tubular epithelial inflammation by inhibiting autophagy via the PI3K/Akt/mTOR signalling pathway

Protease-activated receptor-2 (PAR2), which belongs to a specific class of the G-protein-coupled receptors, is central to several inflammation processes. However, the precise molecular mechanism involved remains undefined. Autophagy has been previously shown to affect inflammation. In the present study, we examine the effect of PAR2 on kidney tubular epithelial autophagy and on autophagy-related inflammation and reveal the underlying mechanism involved. Autophagic activity and levels of autophagic marker LC3 were examined in human kidney tubular epithelial cells with PAR2 knockdown or overexpression. We administered the mammalian target of rapamycin (mTOR) inhibitor (rapamycin) or activator (MHY1485) to investigate the function of the phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway. We also used transforming growth factor-β1 (TGF-β1)-induced HK-2 cell inflammation models to investigate the role of PAR2-associated autophagy in kidney tubular epithelial inflammation. PAR2 antagonist and rapamycin were administered to mice after unilateral ureteral obstruction to detect the correlations between PAR2, autophagy, and inflammation. Our results show that PAR2 overexpression in HK-2 cells led to a greater reduction in autophagy via the PI3K/Akt/mTOR pathway activation and induces autophagy-related inflammation. Meanwhile, a knockdown of PAR2 via PAR2 RNAi transfection greatly increased autophagy and alleviated autophagy-associated inflammation. In unilateral ureteral obst...
Source: Biochemical Journal - Category: Biochemistry Authors: Tags: Research Articles Source Type: research