Effects of PI3-k/Akt short hairpin RNA on proliferation, fibronectin production and synthesis of thrombospondin-1 and transforming growth factor- β 1 in glomerular mesangial cells induced by sublytic C5b-9 complexes

Objectives : To explore proliferation of glomerular mesangial cells (GMC) and secretion of extracelluar matrix (fibronectin induced by sublytic C5b-9 complexes), and then ascertain the role of phosphatidylinositol 3-kinase (PI3-k)/Akt signal pathway in these processes, by using small hairpin RNAs. Material and methods : The expression of cyclin D 2 , 3 H-thymidine into DNA and production of fibronectin including thrombospondin-1 and transforming growth factorβ 1 in the GMCs stimulated by sublytic C5b-9 or transfected with expression vectors of PI3-k and Akt short hairpin RNA or LY294002 (PI3-k inhibitor) were measured by Realtime quantitative polymerase chain reaction (PCR), Western blot, enzyme-linked immunosorbent assay (ELISA) and 3 H-thymidine incorporation ( 3 H-TdR), respectively. Results : The expression of cyclin D 2 , 3 H-thymidine into DNA and fibronectin in the GMCs stimulated by sublytic C5b-9 could all be increased, and the elevations of these parameters mentioned above were also markedly reduced in the GMCs transfected with vectors of PI3-k and Akt short hairpin RNA or LY294002, respectively. Conclusions : These data indicate that sublytic C5b9 can promote proliferation of GMCs and secretion of fibronectin as well as synthesis of thrombospondin-1 and transforming growth factorβ 1 . The PI3-k/Akt signal pathway in these reactions, mediated by sublytic C5b-9 complexes, may play at least a partial role.