Identification of Nef-HIV-1 domains involved in p22-phox interaction and superoxide production / Identificación del dominio de Nef-VIH-1 involucrado en la interacción con p22-phox y producción de superoxido

Nef -HIV-1 has been shown to be involved in NADPH complex interaction and superoxide production. The aim of this work was to study the domains involved in the interaction between Nef and p22-phox. Two approaches were used: 1) in silico modelling, to determine the potential binding motifs and design Nef truncated forms and 2) functional assays. The results showed that GFPVT 68-72, FPDW 121-124 and REVLE 179-183 on Nef are critical for p22-phox (RPQIG 142-146 and PGGP 181-184) docking. However, only the region containing FPDW 121-124 on Nef is able to induce superoxide production. Understanding the molecular mechanisms involved in generating oxidative stress during HIV infection, is critical for therapeutic intervention, in order to minimize viral replication and dissemination.

Se ha evidenciado que Nef-VIH-1 está involucrado en la interacción con el complejo NADPH y la producción de superóxido. El objetivo de este trabajo fue identificar los dominios implicados en la interacción entre Nef y p22-phox. Se utilizaron dos estrategias: 1) análisis in silico para determinar los posibles motivos de unión y el diseño Nef formas truncadas y 2) ensayos funcionales. Los resultados mostraron que GFPVT 68-72, FPDW 121 a 124 y 179 a 183 REVLE de Nef son críticos para su unión con p22-phox (RPQIG 142-146 y 181-184 PGGP). Sin embargo, sólo la región que contiene FPDW 121-124 en Nef, es capaz de inducir la producción de superóxido. La comprensión de los mecanismos moleculares implicados en la generación de estrés oxidativo durante la infección por VIH, es crítico para la intervención terapéutica, con el fin de minimizar la replicación y la propagación viral.

Endogenous angiotensin II modulates nNOS expression in renovascular hypertension

Nitric oxide (NO) influences renal blood flow mainly as a result of neuronal nitric oxide synthase (nNOS). Nevertheless, it is unclear how nNOS expression is modulated by endogenous angiotensin II, an inhibitor of NO function. We tested the hypothesis that the angiotensin II AT1 receptor and oxidative stress mediated by NADPH oxidase contribute to the modulation of renal nNOS expression in two-kidney, one-clip (2K1C) hypertensive rats. Experiments were performed on male Wistar rats (150 to 170 g body weight) divided into 2K1C (N = 19) and sham-operated (N = 19) groups. nNOS expression in kidneys of 2K1C hypertensive rats (N = 9) was compared by Western blotting to that of 2K1C rats treated with low doses of the AT1 antagonist losartan (10 mg·kg-1·day-1; N = 5) or the superoxide scavenger tempol (0.2 mmol·kg-1·day-1; N = 5), which still remain hypertensive. After 28 days, nNOS expression was significantly increased by 1.7-fold in the clipped kidneys of 2K1C rats and by 3-fold in the non-clipped kidneys of 2K1C rats compared with sham rats, but was normalized by losartan. With tempol treatment, nNOS expression increased 2-fold in the clipped kidneys and 1.4-fold in the non-clipped kidneys compared with sham rats. The changes in nNOS expression were not followed by changes in the enzyme activity, as measured indirectly by the cGMP method. In conclusion, AT1 receptors and oxidative stress seem to be primary stimuli for increased nNOS expression, but this up-regulation does not result in higher enzyme activity.

Micropartículas plasmáticas: um novo microambiente de sinalização redox transcelular no sistema vascular / Plasmatic microparticles: a novel redox sinaling microenvironment in the vascular system do autor Marcelo de Almeida Pedro

Micropartículas (MP) são estruturas liberadas por células ativadas ou apoptóticas. Artérias de coelhos lesadas por cateter balão liberam MP fosfatidilserina positivas, com atividade NADPH oxidase produtora de O2 após adição de NADPH, inibida DPI , SOD e MnTBAP. Induziram apoptose de células musculares lisas vasculares. Western blot não revelou proteínas responsáveis pela atividade redox (NADPH oxidase e PDI). MP plasmáticas de pacientes após implante de stent coronário não mostraram atividade NADPH oxidase, mas significativa atividade diaforase 24h pós implante, inibida 40-50 por cento por DPI, SOD e catalase / Microparticles (MP) are released by cells upon activation and apoptosis. Balloon injured rabbit arteries released phosphatidilserine positive MP, with O2 producing NADPH oxidase activity upon NADPH addition, inhibited by DPI, SOD and MnTBAP. MP induced cultured vascular smooth muscle cells apoptosis. Western blot did not show redox active proteins (NADPH oxidase and PDI). Plasmatic MP from coronary stented patients did not have NADPH oxidase activity, but had significant diaphorase activity, inhibited 40-50 per cent by DPI, SOD and catalase...