[Role of extracellular matrix in angiotensin II signalling in aortic smooth muscle cells: relationship with arterial hypertension].
Angiotensin II (Ang II) is involved in hypertension-related arterial wall hypertrophy [1]. Regulation of AT II transduction pathway in vascular smooth muscle cells (VSMC) may involve cytoskeleton and extracellular matrix (ECM) [2]. We assessed the role of components of ECM on Cai2+ increase induced by Ang II in Wistar-Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR) aortic VSMC. The effect of Ang II (1 mumol) on Ca2+ mobilization was studied in cultured VSMC isolated from the aorta of 6-wk old WKY (MAP (m +/- SE) = 98 +/- 4 mmHg) and SHR (136 +/- 5 mmHg; p < 0.05), using fluorescent imaging microscopy (Fura-2 AM). Cai2+ release from internal stores and Ca2+ influx were assessed in the absence and upon reintroduction of external Ca2+ respectively. Cells were cultured on uncoated glass coverslips (control) or coated with either collagen I (10 micrograms/mL), collagen IV (7 micrograms/mL), vitronectin (0.1 microgram/mL), fibronectin (3 micrograms/mL) and extracellular matrix extract (matrigel, 1/10) and studied at confluence. Paxillin was located in cells by indirect immunofluorescence micrography. Results are expressed in % of Control. Statistical significance (p < 0.05) was assessed with Student's t-test for unpaired data. The effects on Ang II-induced Ca2+ mobilization of growing cells on ECM are in Table. Paxillin in Control cells appeared as dots at the cell boundaries. Density increased in cells grown on collagen I with a diffuse distribution in the WKY cells. On matrigel, paxillin was located in a belt-like fashion at the periphery of the cell. These effects were not linked to differences in cell cycle (flux cytometry).
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000502:physiology*; D015220:Calcium Channels; D018929:Cell Culture Techniques; D005109:Extracellular Matrix / Q000502:physiology*; D006973:Hypertension / Q000503:physiopathology; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D015398:Signal Transduction
D015220:Calcium Channels; D000804:Angiotensin II
Rôle de la matrice extracellulaire dans la signalisation de l'angiotensine II dans les cellules musculaires lisses aortiques: relation avec l'HTA.