title: Effect of caveolin-1 scaffolding peptide and 17beta-estradiol on intracellular Ca2+ kinetics evoked by angiotensin II in human vascular smooth muscle cells.
abstract: Caveolae are identifiable plasma membrane invaginations. The main structural proteins of caveolae are the caveolins. There are three caveolins expressed in mammals, designated Cav-1, Cav-2, and Cav-3. It has been postulated that Cav-1 acts as a scaffold protein for signaling proteins; these include ion channels, enzymes, and other ligand receptors like membrane-associated estrogen receptor (ER)alpha or ERbeta. Caveolae-associated membrane proteins are involved in regulating some of the rapid estrogenic effects of 17beta-estradiol. One important system related to the activity of ERalpha and caveolae is the renin-angiotensin system. Angiotensin II (ANG II) has numerous actions in vascular smooth muscle, including modulation of vasomotor tone, cell growth, apoptosis, phosphatidylinositol 3-kinase (PI3K)/Akt activation, and others. Many proteins associated with caveolae are in close relation with the scaffolding domain of Cav-1 (82-101 amino acid residues). It has been proposed that this peptide may acts as a kinase inhibitor. Therefore, to explore the ability of Cav-1 scaffolding peptide (CSP-1) to regulate ANG II function and analyze the relationship between ERalpha and ANG II type 1 and 2 (AT(1) and AT(2)) receptors, we decided to study the effects of CSP-1 on ANG II-induced intracellular Ca(2+) kinetics and the effect of 17beta-estradiol on this modulation using human smooth muscle cells in culture, intracellular Ca(2+) concentration measurements, immuno- and double-immunocytochemistry confocal analysis of receptor expression, immunoblot analysis, and immunocoprecipitation assays to demonstrate coexpression. We hypothesized that CSP-1 inhibits ANG II-mediated increases in intracellular Ca(2+) concentrations by interfering with intracellular signaling including the PI3K/Akt pathway. We also hypothesize that AT(2) receptors associate with Cav-1. Our results show that there is a close association of AT(1), AT(2), and ERalpha with Cav-1 in human arterial smooth muscle cells in culture. CSP-1 inhibits ANG II-induced intracellular signaling.
authors.affiliation: Laboratorio Multidisciplinario, Sección de Posgrado, Escuela Superior de Medicina, Instituto Politécnico Nacional, México City, México.
authors.forename: Enrique
authors.initials: E
authors.lastname: Méndez-Bolaina
authors.forename: Javier
authors.initials: J
authors.lastname: Sánchez-González
authors.forename: Israel
authors.initials: I
authors.lastname: Ramírez-Sánchez
authors.forename: Esther
authors.initials: E
authors.lastname: Ocharán-Hernández
authors.forename: Marisol
authors.initials: M
authors.lastname: Núñez-Sánchez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Meaney-Mendiolea
authors.forename: Alejandra
authors.initials: A
authors.lastname: Meaney
authors.forename: Juan
authors.initials: J
authors.lastname: Asbun-Bojalil
authors.forename: Angel
authors.initials: A
authors.lastname: Miliar-García
authors.forename: Ivonne
authors.initials: I
authors.lastname: Olivares-Corichi
authors.forename: Guillermo
authors.initials: G
authors.lastname: Ceballos-Reyes
mesh_terms: D000804:Angiotensin II / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D004958:Estradiol / Q000502:physiology*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; D047628:Estrogen Receptor alpha; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D000804:Angiotensin II; D004958:Estradiol; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D002118:Calcium