INVESTIGADORES
PODEROSO Juan Jose
congresos y reuniones científicas
Título:
iNOS translocation to mitochondria and septic failure
Autor/es:
CARRERAS MC; FRANCO MC; HOLOD S; ANTICO ARCIUCH VG; PODEROSO JJ
Lugar:
Monterey, EEUU
Reunión:
Congreso; 4th International Conference: Biology, Chemistry, & Therapeutic Applications of Nitric Oxide; 2006
Institución organizadora:
NO Society
Resumen:
In endotoxemia or bacteremia, nitric oxide increases mitochondrial oxygen free radical and endogenous peroxynitrite formation followed by severe functional organelles impairment. Considering that iNOS-related dysoxia is the basic mechanism for  multi-organ  failure, we  studied  iNOS translocation to rat liver and muscle mitochondria in vivo 2-24 h after IP injection of 10-20 mg/Kg E.coli LPS and by transcription-translation in vitro. Endotoxemia induced iNOS at 2-4 h that appeared in mitochondria with a peak at 6 h, and was not removed by proteinase K; differently to modified nNOSá (the so-called mtNOS) that reaches the inner membrane, iNOS remained at the intermembrane space and outer membrane. In the same period, nitration and oxidation of mitochondrial proteins were maximally detected at 4-6 h; at 12 h, translocation was associated with 40-50% inhibition of complexes I and IV (p<.05), which was not reversed at 24 h. Expression of chaperones eukaryote HSP90 or prokaryote Dna-K did not change, while HSP70 increased at 12-24 h and mitochondrial transcription factor A mRNA at a more prolonged time. In addition, in vitro transcription and translation with iNOS cDNA in a piNOSL8 vector with T7 bacterial promoter produced the enzyme; the synthesized product associated slightly with normal mitochondria but translocated to mitochondria from septic animals in the presence of cytosolic fraction from septic tissues. The results suggest that in sepsis, iNOS overexpression is not merely a requisite to enter to mitochondria and that, bacterial or host factors associated to LPS are required for translocation to the organelles and organ damage that likewise is repaired by mitochondrial biogenesis.