IL-17 Regulates TGF-?-induced Fibrosis Associated Protein Expressions And Their Signaling In Fibroblast From Different Tissue

Background:Renal interstitial fibrosis is a common pathologic change of all end-stage chronic renal disease(CKD).The progression of renal interstitial fibrosis is companied by inflammatory cells infiltration,fibroblasts activation,extracellular matrix synthesis,and so on.In addition,the development of renal interstitial fibrosis is also concerned with different kinds of cytokines and signaling pathways [1-4].Interleukin-17(IL-17)mainly produced by Th17 cells,is a kind of proinflammatory cytokine that received much concern recent years [5,6,7].The receptor of IL-17(IL-17R),is widely expressed on the surface of different kinds of cells[8].Nowadays,it is widely reported that IL-17 can promote myocardiac,pulmonary and hepatic fibrosis [9-13].However,the interaction between IL-17 and renal interstitial fibrosis has being unclear.Recently,we induced renal interstitial fibrosis in IL-17 knockout mice and WT mice by unilateral ureteral obstruction(UUO).We found that IL-17 knockout mice developed more severe renal interstitial fibrosis than WT mice [16].This is discount with the reports that IL-17 can contribute to myocardial,pulmonary and hepatic fibrosis.Therefore,it is necessary to analyze the effect of IL-17 on renal fibroblasts in vitro and possible mechanisms.We created cell culti-vation system in vitro,observed and compared the effect of IL-17 on the transformation of mouse primary renal fibroblasts,rat renal fibroblast cell line NRK-49 F,mouse primary pulmonary fibroblasts and mouse embryo fibroblast cell line BALB/3T3 to myofibroblasts and investigated the molecular mechanism.And eventually it will be confirmed in mice after UUO model.Objective:To study the effect of IL-17 on the transformation of renal fibroblasts to myofibroblasts and the expression of extracellular matrix,and further to investigate the possible mechanisms.Method:1.Mouse primary renal fibroblasts,rat renal fibroblast cell line NRK-49 F,mouse primary pulmonary fibroblasts and mouse embryo fibroblasts cell line BALB/3T3 were cultured and induced to transformate into myofibroblast and express fibrosis-associated proteins by TGF-? in vitro.IL-17 was added into the culture in order to study the effect of IL-17 on fibrosis development.2.The expressions of ?-SMA,fibronectin and type 1 collagen by mouse primary renal fibroblasts,rat renal fibroblast cell line NRK-49 F,mouse primary pulmonary fibroblasts and mouse embryo fibroblasts cell line BALB/3T3 were measured by Western blotting.3.The phosphorylation levels of Smad2 and Smad3,TGF-? classic signaling molecules,and of p38 MAPK and Akt,TGF-? non-classical signaling molecules,in these fibroblasts treated by TGF-? with or without IL-17,and in the renal tissue of IL-17-/-and WT mice were measured by Western blotting.Result:In mouse primary renal fibroblasts and rat renal fibroblast cell line NRK-49 F,IL-17 inhibited TGF-?-induced expressions of ?-SMA,fibronectin and type 1 collagen by decreasing the phosphorylations of Akt and p38 MAPK.And it was confirmed in mice after UUO model.While in mouse primary pulmonary fibroblasts,IL-17 promoted TGF-?-induced expressions of ?-SMA,fibronectin and type 1 collagen by increasing the phosphorylations of p38 MAPK.IL-17 had no significant effect on the expression of ?-SMA,fibronectin and type 1 collagen by mouse embryo fibroblasts cell line BALB/3T3.Conclusion:IL-17 exerted different effects on the development of fibrosis and expression of fibrosis-associated proteins depending on different tissues fibroblasts.In renal fibroblasts,IL-17 inhibited myofibroblast transformation and expressions of ?-SMA,fibronectin and type 1 collagen induced by TGF-? through inhibiting the phosphorylation of non-classical pro-fibrosis signaling molecules Akt and p38 MAPK.