Changes of typeI,III collagen expression in cultured rat glomerular mesangial cells transfected with Smad 7 cDNA

Objective To investigate the changes of typeⅠ,Ⅲ collagen(ColⅠ,Col Ⅲ)expression on cultured rat glomerular mesangial cells(MsC)transfected with Smad 7 cDNA in order to provide experimental proofs for blocking renal fibrosis with Smad 7 gene therapy.Methods Lipofectin method was used to transfect Smad 7 cDNA into MsC,and transfected cells were selected with G418.Smad 7 mRNA and protein expression was detected by Northern blot and Western blot analysis,respectively.The expression of typeⅠ,Ⅲ collagen on MsC were determined by reverse transcription-polymerase chain reaction(RT-PCR)and Western blot analysis.Results Overexpression of Smad 7 on two MsC clones(S-22,S-26)was successfully established.Two MsC clones showed decreased expression of ColⅠ,Col Ⅲ mRNA and their proteins.The level of ColⅠ,Col Ⅲ mRNA expression on S-22 clone decreased 47% and 56% respectively.However,the level of their protein expression decreased by 65% and 54%,respectively.Conclusions It is suggested that Smad 7 could alleviate the progression of renal fibrosis by down-regulating the expression of ColⅠ and Col Ⅲ at mRNA and protein level.