Adrenomedullin promotes cell-cell contact formation of podocytes through regulating Rho GTPases / 中华肾脏病杂志

ABSTRACT

Objective To investigate the regulatory effect of adrenomedullin (AM) on the cell-cell contact formation of podocytes and the possible mechanism.Methods Podocytes were treated with AM (10-7 mol/L),AM combined with a PKA inhibitor H89 (10-4 mol/L),and forskolin (10-5 mol/L) as positive control respectively for 12 hours.Immunofluorescent staining was applied to observe the distribution of cell adhesion molecules and actin-associated proteins.Western blotting assay was used to assess their protein levels.Rho GTPases activity was analyzed by GST-pull down assay and their protein levels were tested by Western blotting.Results AM induced the redistribution of adhesion molecules,actin-associated proteins as well as the F-actin at cell-cell contacts between podocytes.This effect was similar to that of forskolin and could be blocked by H89.The levels of those proteins did not change significantly (P ＞ 0.05).AM up-regulated the activities of RhoA,Rac1 and Cdc42 (P ＜ 0.05),which were partially blocked by H89.The protein levels of Rho GTPases showed no difference compared with the control (P ＞ 0.05).Conclusions AM may promote cell-cell contact formation of podocytes,probably through enhancing the activity of Rho GTPases and then resulting in the redistribution of adhesion molecules,actin-associated proteins and F-actin,which is partially mediated through cAMP-PKA signaling pathway.