Effect Of Complement 3 On Changing Of Phenotype In Human Renal Proximal Tubular Epithelial Cells

Objective To investigate the effect of complement 3 on changing of phenotype in human renal proximal tubular epithelial cells.Methods(1) Cultured HK-2 were treated with 50ng/ml IFN-γor 10ng/ml TNF-αfor 24 hours.HK-2 cells were divided into the following groups according to different factors:Control group,IFN-γgroup,TNF-αgroup.The expression of C3 mRNA and protein were analysed by RT-PCR and Western Blot.(2) HK-2 were cultured with 0.1μM C3a for 24 hours.The expression ofα-SMA and E-cadherin were detected by indirect immunofluorescence.(3) HK-2 were divided into the following groups:Control group,0.1μM C3a group,50ng/ml IFN-γ,group,10ng/ml TNF-αgroup and cultured with different factors for 24 hours.The levels ofα-SMA and E-cadherin were measured by RT-PCR and western Blot.Results(1) Cultured HK-2 expressed C3 mRNA and protein,and levels were increased in response to 50ng/ml IFN-7 and 10ng/ml TNF-α(P＜0.01).(2) Indirect immunofluorescence staining showed that expressions ofα-SMA,the phenotypic marker of myofibroblasts,were upregulated and enhanced by 0.1μM C3a after 24h,but not expressed in control cells.The expressions of E-cadherin, the tubular epithelial cell-cell adhesion receptor,were dramatically repressed by 0.1μM C3a after 24h. (3) The expressions ofα-SMA were increased in response to 0.1μM C3a,50ng/ml IFN-γand 10ng/ml TNF-αafter 24h(P＜0.01).Otherwise,the expressions of E-cadherin were downregulated by 0.1μM C3a,50ng/ml IFN-γand 10ng/rnl TNF-αafter 24h(P＜0.01).Conclusions(1) In vitro,HK-2 can express C3.The expression of C3 in HK-2 can be upregulated and enhanced by IFN-γand TNF-α.(2) Exogenous C3a upregulates the expressions ofα-SMA on the level of transcription and translation,and decreases the expressions of E-cadherin,which resulting in the phenotypic Wansformafion of HK2.These results suggest that C3 can induce epithelial to mesenchymal transition(EMT).(3) The over-expression of C3 in local renal tissue induced by IFN-γand TNF-αmay cause renal.pathologic injury,which plays an important role in renal diseases.