Reactive oxygen species (ROS) as signaling molecules in hepatocytes: tert-butyl hydroperoxide (tBOOH) induces actin cytoskeleton disorganization by a PKC-mediated, Ca2+-dependent mechanism

PÉREZ LM; OCHOA JE; BASIGLIO CL; SANCHEZ POZZI EJ; ROMA MG

Buenos Aires

Congreso; 12th Biennial Meeting of the Society for Free Radical Research International (SFRR 2004); 2004

Society for Free Radical Research (SFRR)

ROS can produce damage in different cell lines by modulating signaling pathways rather than by oxidizing the affected structures. Since ROS can activate PKC, we analyze its participation in oxidative stress-induced actin disorganization in rat hepatocytes, an early ROS-mediated event. For this purpose, the capability of PKC inhibitors to prevent the harmful effect of the pro-oxidant agent, tBOOH, was analyzed. To discard an effect of PKC on tBOOH-induced ROS formation, we also evaluated wether PKC inhibitors affect this process. tBOOH (100 µM) increased ROS formation, as indicated by an enhanced lipoperoxidation (+248 ± 44%, p<0.05) and intracellular production of 2´,7´-dicholofluorescein from 2´,7´-dicholofluorescin/DA (+37 ± 4%, p<0.05). tBOOH increased the amount of isolated rat hepatocyte couplets displaying membrane blebs (68 ± 4% vs 18 ± 2%, p<0.001), and caused extensive redistribution of actin from its normal pericanalicular location. Both events were prevented by the PKC inhibitors, H7 (100 µM), staurosporine (1 µM) and Gö6976 (2 µM), by the Ca2+ chelator, BAPTA/AM (20 µM), and by the PKA activator, dibutyryl-AMPc (500 µM). Conversely, tBOOH-induced ROS production was not modified by any of these pretreatments. We conclude that ROS induces actin cytoskeleton rearrangements in hepatocytes acting as signalling molecules in the PKC-mediated, Ca2+-dependent transductional cascade, an event counteracted by PKA.