Importance of intracellular angiotensin II in vascular smooth muscle cell apoptosis: inhibition by the angiotensin AT1 receptor antagonist irbesartan.
The intracellular uptake of Angiotensin II has been described, although its physiological role is not yet understood. We aimed to study the role of Angiotensin II internalization in Angiotensin II-induced apoptosis. Vascular smooth muscle cells were cultured from male Wistar-Kyoto rats and treated with Angiotensin II (1 microM, 48 h). Apoptosis was assessed by DNA fragmentation, cell cytometry and caspase-3 activity. The Angiotensin AT(1) receptor antagonist irbesartan (0.1-10 microM) and the inhibitors of Angiotensin II internalization phenylarsine oxide (PAO, 20 microM), but not the AT(2) receptor antagonist PD123319 (S-(+)-1-[(4-(Dimethylamino)-3-methylphenyl)methyl]-5-(diphenylacetyl)-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid di(trifluoroacetate) salt), decreased Angiotensin II-mediated apoptosis. Pre-treatment with irbesartan, but not with PD123319, blocked Angiotensin II internalization. We found a strong correlation between intracellular Angiotensin II staining and Angiotensin II-induced apoptosis for all compared groups. We therefore conclude that internalization of Angiotensin II is involved in apoptosis of vascular smooth muscle cells induced by this peptide.
Ruiz
Emilio
E
Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Av. Complutense, s/n. 28040 Madrid, Spain.
Redondo
Santiago
S
Padilla
Eugenia
E
Gordillo-Moscoso
Antonio
A
Salaices
Mercedes
M
Balfagón
Gloria
G
Tejerina
Teresa
T
D000804:Angiotensin II / Q000502:physiology*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001152:Arsenicals / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D007093:Imidazoles / Q000494:pharmacology; D000077405:Irbesartan; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D044139:Receptor, Angiotensin, Type 2 / Q000187:drug effects; D013777:Tetrazoles / Q000494:pharmacology*; D014162:Transfection
D047228:Angiotensin II Type 1 Receptor Blockers; D001152:Arsenicals; D001713:Biphenyl Compounds; D007093:Imidazoles; D011725:Pyridines; D044139:Receptor, Angiotensin, Type 2; D013777:Tetrazoles; C029341:oxophenylarsine; D000804:Angiotensin II; C073402:PD 123319; D053148:Caspase 3; D000077405:Irbesartan