Expressions of miR-21 and SnoN in kidney of diabetic rats / 基础医学与临床

Objective To investigate the expression and possible mechanism of miR-21 and Ski-related novel protein N( SnoN) in the renal fibrosis diabetic process.Methods The animal model was established by tail-vein injection of Streptozotocin,and the other group were normal control ( NC) group.After 10 weeks, the rats were sacrificed to measure biochemical parameters and renal index , and to observe the changes of pathomorphology by HE staining as well.Meanwhile, immunohistochemistry and Western blot were employed to examine protein ex-pression of E-cadherin,α-smooth muscle actin(α-SMA), fibronectin(FN), collagen-Ⅰ(Col-Ⅰ), collagen-Ⅲ(Col-Ⅲ), transforming growth factor-β1(TGF-β1), Smad3, p-Smad3(Ser423/425) and SnoN in the renal tissue. In addition, the expression of SonN mRNA and miR-21 were detected by qPCR.Results In DM group,the ex-pressions of Col-Ⅰ, Col-Ⅲ and FN in renal interstitium were increased ( P <0.05 ) , TGF-β1 increased (P<0.05),while E-cadherin decreased(P<0.05).Compared with NC group, the expression of α-SMA,p-Smad3 (Ser423/425) protein increased in DM group(P<0.05),while the protein level of SnoN decreased but the level of SnoN mRNA increased ( P <0.05 ) .Moreover, the level of miR-21 markedly increased in DM group ( P <0.05 ) .Conclusions TGF-β1 may up-regulate the expression of miR-21 but restrain the translational expression of SnoN, aggravating fibrosis.

Effects of MG132 on protein expression of SnoN and fibrosis-related in-dicators in NRK-52E cells after incubated with high concentration of glu-cose / 中国病理生理杂志

AIM:To investigate the effects of proteasome inhibitor MG 132 on the expression of SnoN in renal tubule epithelial cells incubated in high glucose , and to explore the possible mechanism and function that MG 132 reduces or slows down renal tubular interstitial injury after incubated in high glucose .METHODS:The NRK-52E cells were divid-ed into normal control group (NG), high glucose group (HG) and high glucose plus pretreatment with different doses of MG132 group (HG+MG132).The immunofluorescence staining was used to detect the protein expression of E-cadherin and α-smooth muscle actin (α-SMA) in NRK-52E cells under different conditions .The relative protein expression levels of SnoN, Smad ubiquitination regulatory factor 2 (Smurf2), Arkadia, E-cadherin, α-SMA and collagen type Ⅰ(Col-Ⅰ) were detected by Western blotting .RESULTS:Compared with NG group , the expression of E-cadherin and SnoN was de-creased (P<0.05), while the expression of α-SMA, Col-Ⅰ, Smurf2 and Arkadia was increased (P<0.05).Compared with HG group, the protein expression of SnoN and E-cadherin was significantly up-regulated in HG+MG132 group ( P<0.05 ) , and the protein expression of α-SMA and Col-Ⅰwas significantly down-regulated in a dose-depended manner ( P<0.05).However, no effect on the protein expression of Smurf2 and Arkadia was observed.CONCLUSION: MG132 in-hibits the degradation of SnoN protein induced by high glucose , thus reducing the renal fibrosis .