Nitric oxide induces HIF-1α stabilization and expression of intestinal trefoil factor in the damaged rat jejunum and modulates ulcer healing.

BACKGROUND: The induction of intestinal trefoil factor (ITF) has been reported to depend on hypoxia-inducible factor-1 (HIF-1). Nitric oxide modulates HIF-1 activity. The present study aims to analyze the role of nitric oxide in jejunum damage induced by indomethacin and its ability to modulate epithelial function through the expression of ITF. METHODS: Rats received indomethacin (7.5 mg/kg, s.c., twice), and a time course analysis of damage was performed (24-96 h after the first administration). In these animals, the role of nitric oxide was analyzed by using 1400W, a selective iNOS activity inhibitor (5 mg/kg, i.p./day), on: (1) intestinal damage, (2) ulcer healing, (3) the presence of nitrated proteins in the jejunum and (4) the protein expression of inducible nitric oxide synthase (iNOS), HIF-1α and ITF. RESULTS: Indomethacin induced damage in the jejunum that was apparent at 24 h and peaked at 48-72 h. An increase in iNOS, HIF-1α, ITF and nitrated proteins was observed in the injured jejunum. Immunoprecipitation of HIF-1α allowed determination of the nitration/nitrosylation of this protein by using nitrotyrosine and nitrocysteine antibodies. Blockade of iNOS activity did not significantly modify damage or iNOS expression, but did significantly impede ITF induction, HIF-1α stabilization and HIF-1α detection with antibodies against nitrated proteins. In parallel to these results, pre-treatment with 1400W delayed the healing of the ulcer provoked by indomethacin. CONCLUSIONS: These results suggest that iNOS-derived NO is involved in HIF-1α stabilization, probably through S-nitrosylation, and ITF expression in goblet cells of the damaged jejunum of indomethacin-treated rats and mediates ulcer healing.

PROTEÍNAS ANTIFÚNGICAS CONTRA P. INFESTANS EN LOS ESPACIOS INTERCELULARES DE HOJAS DE TOMATE (Lycopersicon esculentum cerasiforme) POSIBLES DEFENSINAS DE PLANTAS / ANTIFUNGAL PROTEINS AGAINST P. INFESTANS FROM INTRACELLULAR SPACE OF TOMATO LEAVES (Lycopersicon esculentum cerasiforme) POSSIBLE DEFENSINS OF PLANTS

Se aislaron y caracterizaron parcialmente proteínas antifúngicas de los espacios intercelulares de hojas de tomate Lycopersicon esculentum cerasiforme, variedad que ha mostrado resistencia en campo a Phytophthora Infestans; se observó que después de inoculación con el patógeno dichas proteínas se acumularon sistémicamente en la planta. Las proteínas identificadas mostraron características de Defensinas de plantas, una nueva familia de proteínas con bajo peso molecular, carga positiva a pH fisiológico y actividad antifúngica evaluada in vitro contra P. infestans. Los análisis electroforéticos en geles de poliacrilamida con SDS-Tricina en condiciones reductoras y no reductoras, sugirieron que están asociadas en trímeros y tetrámeros y poseen pesos moleculares de 5,2 kDa.

Antifungal Proteins from intercellular space of Tomato leaves Lycopersicon esculentum cerasiforme were isolated and partially characterized; this variety had shown resistance against Phytophthora infestans, after inoculating plants with the pathogen it was observed that these proteins were accumulated systemically. The isolated proteins be haved as plant defensins, a novel protein family, with low molecular weight, cationics at physiological pH and Antifungal Activity in vitro evaluated against P. infestans. Electrophoretic analyses in SDS Tricine-PAGE, under reducing and non-reducing conditions suggested that, they were associated as trimers and tetramers; and have molecular weights of 5,2 kDa.