TGF?-Induced Actin Cytoskeleton Rearrangement in Podocytes Is Associated with Compensatory Adaptation of Mitochondrial Energy Metabolism.

ABSTRACT: In podocytes, the overexpression of TGF? ligands and receptors during glomerulosclerosis could be a causal factor for injury induction and perpetuation in glomerular tufts. Mitochondrial dysfunction and oxidative stress are emerging as potential therapeutic targets in glomerular injury, and TGF? has been shown to modulate mitochondrial metabolism in different cell types. This study aims at investigating the role of TGF? in podocyte energy metabolism and cytoskeleton dynamics.Mitochondrial function and cytoskeleton dynamics were analyzed in TGF?-treated WT and Smad2/3 double KO podocytes.TGF? treatment in podocytes induced a significant Smad-dependent increase of mitochondrial oxygen consumption rate (OCR). ATP content was unchanged and increased respiration was not associated with increased mitochondrial mass. Increased cellular reactive oxygen species induced by Smad-mediated TGF? signaling were reverted by NADPH oxidase inhibitor apocynin. TGF? treatment did not induce mitochondrial oxidative stress, and Smad2/3-dependent TGF? signaling and increased mitochondrial OCR were found to be associated with actin cytoskeleton dynamics. The role of motor proteins myosin II and dynamin in TGF?-induced actin polymerization was demonstrated by specific inhibition, resulting in actin stabilization and normalization of mitochondrial OCR.TGF?-induced rearrangements of actin cytoskeleton are controlled by Smad2/3 signaling pathways and coupled with the activation of mitochondrial ATP synthesis as bioenergetic adaptation to ATP consumption by ATP- and GTP-dependent motor proteins, myosin II and dynamin.

SUBMITTER: Casalena G 

PROVIDER: S-EPMC4687741 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature