Chemotactic effect of prorenin on human aortic smooth muscle cells: a novel function of the (pro)renin receptor.
OBJECTIVE
The discovery of a specific prorenin receptor (PRR) suggests a biological function of prorenin that is independent of angiotensin I production. In the present study, we investigated the role of PRR on smooth muscle cell (SMC) migration.


RESULTS
PRR was expressed in human mammary arteries and in cultured human aortic SMCs. Prorenin induced SMC migration in a dose-dependent manner, as assessed by Boyden chamber chemotaxis assay, and increased SMC random motility, as determined by video microscopy. The prorenin decoy peptide inhibited SMC migration in response to prorenin, and knockdown of PRR by small interfering RNA completely inhibited the migratory response to prorenin, demonstrating that the chemotactic action of prorenin is mediated by the PRR. Prorenin induced cytoskeleton reorganization and lamellipodia formation and increased the intracellular levels of both RhoA-GTP and Rac1-GTP through PRR. These effects were required for SMC migration, because the suppression by small interfering RNA of either Rac1 or RhoA GTP-bound forms completely blocked the PRR-mediated chemotactic effect. Prorenin also induced the formation of larger focal adhesions and cleavage of the focal adhesion kinase (pp125(FAK)) into two main fragments with molecular weights of 50 and 90 kDa. The generation of these two fragments of pp125(FAK) was reduced by the calpain inhibitor ALLN, which also inhibited SMC migration in response to prorenin.


CONCLUSIONS
These results demonstrate that prorenin is a chemotactic factor for human aortic SMCs expressing PRR. This effect is elicited through reorganization of the cytoskeleton and focal adhesion, activation of RhoA and Rac1, and calpain-mediated cleavage of pp125(FAK).
Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Via Balzaretti 9, Milan, Italy.
Carolina M
CM
Greco
Marina
M
Camera
Laura
L
Facchinetti
Marta
M
Brambilla
Sara
S
Pellegrino
Maria Luisa
ML
Gelmi
Elena
E
Tremoli
Alberto
A
Corsini
Nicola
N
Ferri
D001011:Aorta / Q000378:metabolism; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D018715:Microscopy, Video; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism*; D034622:RNA Interference; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D012083:Renin / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D000093342:Prorenin Receptor
D015853:Cysteine Proteinase Inhibitors; D010446:Peptide Fragments; D011498:Protein Precursors; C107953:RAC1 protein, human; D011956:Receptors, Cell Surface; C066737:RHOA protein, human; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D002154:Calpain; D012083:Renin; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein; D000093342:Prorenin Receptor