title: Both AT₁ and AT₂ receptors mediate proliferation and migration of porcine vascular smooth muscle cells.
abstract: Angiotensin receptor antagonists have shown clinical promise in modulating vascular disease, in part by limiting smooth muscle cell proliferation and migration. The majority of studies examining the contribution of these receptors have been undertaken in cells derived from rat aorta, which primarily express the ANG II type 1 (AT(1)) receptor. This investigation studied the relative contribution of AT(1) and ANG II type 2 (AT(2)) receptors to the mitogenic program of porcine smooth muscle cells. Smooth muscle cells were derived from porcine coronary artery explants. The presence of both AT(1) and AT(2) receptors was demonstrated through ligand binding and RT-PCR analysis. Biochemical and cellular markers of proliferation were monitored in the presence of selective receptor antagonists. Smooth muscle cell migration was measured using both wound healing and Boyden chamber migration assays. Visualization of the AT(1) and AT(2) receptors in growing and quiescent porcine smooth muscle cells with epifluorescence microscopy demonstrated that their subcellular distribution varied with growth state. An examination with several growth assays revealed that both AT(1)-specific losartan and AT(2)-specific PD-123319 receptor antagonists inhibited ANG II-stimulated RNA and DNA synthesis, PCNA expression, and hyperplasia. ANG II induced both directional and nondirectional cell migration. AT(1) receptor antagonist treatment significantly decreased ANG II-induced directional migration only, whereas AT(2) receptor antagonist treatment significantly reduced both modes of migration. Interestingly, the focal adhesion kinase inhibitor PF-573228 also blocked migration but not proliferation. Furthermore, focal adhesion kinase activation in response to ANG II was prevented only by PD-123319, indicating that this activation is downstream of the AT(2) receptor. The observed role of the AT(2) receptor in ANG II-induced migration was confirmed with smooth muscle cells depleted of the AT(2) receptor with short hairpin RNA treatment.
authors.affiliation: Canadian Centre for Agri-Food Research in Health and Medicine, Saint Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada.
authors.forename: Sherif
authors.initials: S
authors.lastname: Louis
authors.forename: Laura
authors.initials: L
authors.lastname: Saward
authors.forename: Peter
authors.initials: P
authors.lastname: Zahradka
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D057912:Angiotensin II Type 2 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D019808:Losartan / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology; D034622:RNA Interference; D044140:Receptor, Angiotensin, Type 1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D044139:Receptor, Angiotensin, Type 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013450:Sulfones / Q000494:pharmacology; D013552:Swine; D013997:Time Factors
chemical_list: C521108:6-(4-(3-(methylsulfonyl)benzylamino)-5-(trifluoromethyl)pyrimidin-2-ylamino)-3,4-dihydroquinolin-2(1H)-one; D047228:Angiotensin II Type 1 Receptor Blockers; D057912:Angiotensin II Type 2 Receptor Blockers; D007093:Imidazoles; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D015363:Quinolones; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D013450:Sulfones; D000804:Angiotensin II; C073402:PD 123319; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019808:Losartan