Examinando por Autor "Miguel, M"

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Efecto de Angiotensina II sobre la expresión de COX-2 y mPGES-1 inducida por Interleuquina-1beta en fibroblastos adventiciales
(2009-07) Miguel, M; Galán, M; Beltrán, AE; Martínez-González, J; Rodríguez, C; Alonso, MJ; Salaices, M
Food derived peptides with vasodilator effect. Structure-activity relationship
(2009-09) García-Redondo, AB; Roque, F; Avendaño, MS; Alonso, MJ; López-Fandiño, R; Miguel, M; Salaices, M
Biologically active peptide fragments are formed during proteolysis of food proteins, and have been shown to possess multiple physiological properties, including properties related to cardiovascular health such as blood pressure lowering effect. Most of food-derived peptides with antihypertensive activity have been also characterized as in vitro angiotensin converting enzyme (ACE) inhibitory agents, but, only a few studies have shown in vivo ACE-inhibitory activity of these peptides. This suggests that other mechanisms of action could be implicated in their antihypertensive effect. The aim of this study was to analyze, in resistance arteries, the vasodilator activity of several peptide sequences obtained from food protein hydrolysates and to establish whether there is a relationship between the aminoacids present in peptide sequences and the vasodilator effect. For this, third order branch of the mesenteric artery from 6 months old male Wistar Kyoto rats were used. The vasodilator response of arterial segments with or without endothelium to several peptides (0.1 mM) was analyzed in an isometric myograph. Moreover, the effect of NO synthase (L-NAME, 100 microM), and ciclooxygenase (indomethacin, 10 microM) inhibitors on the vasodilator response was tested. Peptides RADHPFL, RADHPF, RADHP, YRGGLEPINF, RDILNQ and VPP showed an endothelium-dependent vasorelaxation, whereas the vasodilator effect of FRADHPFL was only partially dependent of endothelium. The maximum relaxation (~75%), belongs to YRGGLEPINF peptide. In addition, the relaxation induced by the peptides RADHPFL, RADHPF, RADHP, RDILNQ and VPP is mainly mediated by NO, since the response was inhibited only by L-NAME, while both L-NAME and indomethacin inhibited the vasodilator response induced by FRADHPFL and YRGGLEPINF. It seems that the presence of arginine or tyrosine in the N-terminal extreme could be related with the vasodilator activity of these compounds. In conclusion, these results suggest that endothelium-dependent relaxation could be also a mechanism involved in the antihypertensive effect of food derived peptides.
p38 MAPK contributes to angiotensin II-induced COX-2 expression in aortic fibroblasts from normotensive and hypertensive rats
(2009-01) Beltrán, A; Briones, AM; García-Redondo, AB; Rodríguez, C; Miguel, M; Alvarez, A; Alonso, MJ; Martínez-González, J; Salaices, M
Objective To investigate the effect of angiotensin II on cyclooxygenase-2 (COX-2) expression in aortic adventitial fibroblasts from normotensive [Wistar¿Kyoto (WKY)] rats and spontaneously hypertensive rats (SHRs). Methods Protein expression was determined by western blot, mRNA levels by real-time PCR, transcriptional activity by luciferase assays, superoxide anion (O2.-) production by dihydroethidine fluorescence and prostaglandin E2 by enzyme immunoassay. Results Angiotensin II (0.1mmol/l, 0.5¿6 h) time dependently induced COX-2 protein expression, this effect being transient in fibroblasts from WKY rats and maintained over time in SHRs. Angiotensin II effect was abolished by valsartan (1mmol/l), an angiotensin II type 1 receptor antagonist. Angiotensin II-induced prostaglandin E2 production was reduced by valsartan and the COX-2 inhibitor NS398 (1mmol/l). Angiotensin II increased O2.- production more in SHR than WKY rats. This increase was reduced by apocynin (30mmol/l) and allopurinol (10mmol/ l), respective nicotinamide adenine dinucleotide phosphate (NADPH) and xanthine oxidase inhibitors. However, angiotensin II-induced COX-2 expression was unaffected by apocynin, allopurinol, tempol (1 mmol/l) or catalase (1000 U/ml). Angiotensin II (2¿30 min) induced p38 mitogen-activated protein kinase (MAPK) phosphorylation, transiently in WKY rats but sustained in SHRs. The p38 inhibitor SB203580 (10mmol/l) reduced angiotensin II-induced COX-2 protein and mRNA levels. The angiotensin II effect was not prevented by inhibition of mRNA synthesis, and angiotensin II was unable to modulate COX-2 transcriptional activity. Conclusions Angiotensin II increases COX-2 expression in aortic fibroblasts through mechanisms including p38 MAPK pathway, independent of reactive oxygen species production and nonmediated by COX-2 transcriptional activity modulation. The sustained angiotensin-induced p38 MAPK activation in SHR cells might be related to the maintained COX-2 expression in this strain.
Péptidos derivados de proteínas alimentarias con actividad vasodilatadora. Relación estructura actividad.
(2009-07) García-Redondo, AB; Roque, FR; Alonso, MJ; Lopez-Fandiño, R; Miguel, M; Salaices, m
Sinergistic effects of Angiotensin II and Interleukin-1ß on COX-2 expression in adventitial fibroblasts
(2009-09) Galán, M; Miguel, M; Beltrán, AE; Martínez-González, J; Rodríguez, C; Alonso, MJ; Salaices, M
Adventitial layer plays a critical role in the regulation of vascular function and structure. Angiotensin II (Ang II) has been implicated in the pathophysiological processes that occur in hypertension through its significant proinflamatory actions in the vascular wall, including the production of inflammatory cytokines. Cyclooxygenase-2 (COX-2) and prostaglandin E synthase-1 (mPGES-1) are induced by several proinflammatory agents like cytokines. The purpose of the present study was to evaluate if Ang II alter the effect of Interleukin-1ß (IL-1ß) on COX-2 and mPGES-1 expression in rat aortic fibroblasts. IL-1ß (10 ng/ml, 24h) increased COX-2 and mPGES-1 mRNA levels, COX-2 protein expression and PGI2 and PGE2 production. Incubation of cells with Ang II (0.1 ¿M, 24 h) did modify neither COX-2 and mPGES-1 expression nor prostaglandin levels but enhanced COX-2 expression and PGI2 production induced by IL-1ß; however Ang II did not change mPGES-1 mRNA levels and PGE2 production after treatment with IL-1ß for 24 hours. The potentiator effect of Ang II was inhibited by losartan (10 ¿M), suggesting that the effect was mediated by activation of AT1 receptor signaling pathway. IL-1ß (10 ng/ml 5-60 min) increased p38 and ERK 1/2 MAP kinases phosphorylation; after coincubation with Ang II, this increase was higher and more sustained. The respective inhibitors of p38 and ERK 1/2, PD98059 (10 ¿M) and SB203580 (10 ¿M) disminished COX-2 expression in cells treated with IL-1ß or with the combination of IL-1ß plus Ang II. These results suggest that Ang II participate in the vascular inflamatory response not only through the increase of cytokines levels but also through the increase of cytokine effects on expression of some proinflammatoy enzymes such as COX-2, but not mPGES-1. This additional effect is thought to be caused by signaling pathways in which p38 and ERK 1/2 MAP kinases are involved.