ABSTRACT
Aim To investigate the effect of thioester-ase superfamily member 4(THEM4)expression on col-lagen secretion in human renal proximal tubular epithe-lial cells (HKC)treated with high glucose. Methods In order to examine the direct effect of THEM4 ex-pression vector on PI3K/ Akt pathway and collagen se-cretion,pYr-ads-4-THEM4 expression vector was con-structed and transfected into the HKC with lipo-fectamine 2000 in vitro. HKC cells were randomly di-vided into four groups:normal glucose group (Con-trol),high glucose group (HG),high glucose plus pYr-ads-4-THEM4 vector group (HG + THEM4 vec-tor) and high glucose plus pYr-adshuttle-4 vector group (HG + V vector). After 48 h with HG stimula-tion,the cells were collected for extraction of protein and phospho-Akt (Ser 473),THEM4,TGF-β1 andα-SMA protein expression were examined by Western blot and immunofluorescence staining respectively. Col Ⅰ and Col Ⅲ were detected using the competitive sandwich ELISA kit according to the manufacturer's instructions. Results High glucose inhibited THEM4 expression,and induced increased phospho-Akt (Ser 473),TGF-β1,α-SMA and secreted ColⅠand secre-ted Col Ⅲ in HKC cells. Up-regulation of THEM4 re-versed high glucose-induced decreased THEM4,in-creased phospho-Akt (Ser 473),TGF-β1,α-SMA, secreted Col Ⅰ and secreted Col Ⅲ in HKC cells. Conclusion The up-regulation of THEM4 may de-crease Col Ⅰ and Col Ⅲ secretion by inhibiting the phosphorylation of Akt and down-regulating the expres-sion of TGF-β1 and α-SMA in high glucose-induced HKC cells.