INVESTIGADORES
PODEROSO Juan Jose
congresos y reuniones científicas
Título:
Mitochondrial nitric oxide synthase and redox modulation of proliferation and cell signaling in neonate hepatocytes
Autor/es:
CARRERAS MC; GALLI S; LORENTI A; BARBICH M; ANTICO ARCIUCH V; FRANCO MC; CONVERSO D; PODEROSO JJ
Lugar:
Seattle, EEUU
Reunión:
Congreso; X Annual Meeting of the Society for Free Radical Biology and Medicine; 2003
Institución organizadora:
Society for Free Radical Biology and Medicine
Resumen:
Modulation of mitochondrial nitric oxide synthase and NO/dependent H2O2 yield plays an important role in cellproliferation, differentiation, apoptosis and senescence. Hepatocytes from postnatal day 2 (P2) still present asynchronized high proliferation rate supported by the expression of cyclin D1, a key regulator of cell cycleprogression. On these bases, P2 hepatocytes were obtained after liver dissagregation with collagenase. Smallround, less differentiated (positive to ovall cell antibodies OC.2-3) and bigger more differentiated P2 cells(positive to hepatocyte antigen) were separated by differential centrifugation (50g), and cultured in Williams Emedium with 10% fetal bovine serum. DNA synthesis was assessed by [3H]thymidine incorporation.Supplementation of P2 cultured hepatocytes with H2O2 (1-1000 µM) or 5 mM L/Arg diminished cell proliferation.In addition, treatment with H2O2 scavengers like N-acetyl cysteine (0.1-10 mM NAC), 5 mM glutathione or 30 µMcatalase, or by 2 mM L-NMMA induced detrimental responses in less differentiated cells but increasedproliferation in more differentiated cells. To test in vivo effectsof H2O2 on signaling, P2 hepatocytes wereexposed to H2O2 (1-50 µM) and 2 mM antimycin and comparatively, to 10 µM anisomycin (a p38 MAPKactivator). According to effects o proliferation, leading P2 cells to adult redox condition, markedly reduced cyclinD1 expression aand ERK/p38 activity ratio. The present results suggest that a synchronized increase of mtNOS,and H2O2 drives transition from proliferation to quiescence.