Induction of HO-1 by nitric oxide in adrenocortical cells involves the stimulation of SGC/PKG and translocation of Nrf2 to the nucleus.

CORA B. CYMERYNG; MARÍA E. MERCAU; ELIÁN F. GIORDANINO; MARÍA C. PROGANO; MATÍAS PEREZ; OMAR A. COSO ; FRANCISCO ASTORT

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Congreso; SISTAM 2012 - The Second South American Spring Symposium in Signal Transduction and Molecular Medicine? (SISTAM2012); 2012

SISTAM

25.- Induction of HO-1 by nitric oxide in adrenocortical cells involves the stimulation of SGC/PKG and translocation of Nrf2 to the nucleus Cora B. Cymeryng, María E. Mercau, Elián F. Giordanino, María C. Progano, Matías Perez, Omar A. Coso and Francisco Astort Department of Human Biochemistry, School of Medicine, University of Buenos Aires, CEFYBO-CONICET, Buenos Aires, Argentina Previous results from our laboratory demonstrated the induction of heme oxygenase 1 in adrenal cells, by endogenously generated nitric oxide (NO), suggesting the involvement of the redox sensible transcription factor Nrf2. However, experiments performed with reporter plasmids yielded conflicting results. The following experiments were designed to analyze the involvement of the Nrf2 signalling pathway in the induction of HO-1 by NO in Y1 adrenal cells. As we have previously shown, increased endogenous NOS activity in Y1 cells resulted in higher cGMP levels. Present experiments showed that incubation of adrenal cells in the presence of a permeable analogue of cGMP (8Br-cGMP) resulted in a significant increase in HO-1 mRNA (p0.05 by Tukey?s test) and protein levels (as shown by RT-PCR and immunoblotting, respectively). This effect was blocked by selective inhibitors for both sGC and PKG activities. Incubation of Y1 cells with a NO-donor also triggered an increase in Nrf2 protein levels that was evident two hours after the initiation of the treatment. Similar results were obtained by immunocytochemical analysis. Three known targets of Nrf2 activation were also significantly increased by NO treatment (GLCL: p