Pulsatile flow-induced angiogenesis: role of G(i) subunits.
OBJECTIVE
Angiogenesis plays a key role in the growth and function of normal and pathological tissues. We investigated the effect of pulsatile flow on endothelial cell (EC) in vitro angiogenic activity.


RESULTS
Bovine aortic ECs were exposed to "static" or "flow" (1.2 to 67.0 mL/min, shear stress 1.4 to 19.2 dyne/cm2) conditions for 2 to 24 hours. After exposure, angiogenesis was measured as tubule formation on Matrigel, and EC migration was assessed by filter migration assay. Pulsatile flow increased angiogenesis and EC migration in a temporal and force-dependent manner, with a maximal effect at 16 hours (13.2 dyne/cm2). Pertussis toxin completely inhibited the effect of pulsatile flow on angiogenesis and migration. Transfection of ECs with inhibitory mutants of the alpha subunit of G(i)1 or G(i)3, but not G(i)2, inhibited the flow-induced angiogenic response by 61+/-2% and 32+/-6%, respectively, whereas transfection with constitutively activated mutants of the alpha subunit of G(i)1 or G(i)3, but not G(i)2, increased the flow-induced response by 202+/-23% and 70+/-4%, respectively. In contrast, inhibition of Gbetagamma by the carboxy terminal fragment of beta-adrenergic receptor kinase overexpression increased the flow-induced response by 82+/-8%.


CONCLUSIONS
These results suggest that pulsatile flow stimulates angiogenesis and that this effect is mediated by activation of G(ialpha)1 or G(ialpha)3, but not Gbetagamma, subunits.
Cullen
John P
JP
Department of Surgery, University of Rochester Medical Center, Rochester, NY 14642-8410, USA.
Sayeed
Shariq
S
Sawai
Rebecca S
RS
Theodorakis
Nicholas G
NG
Cahill
Paul A
PA
Sitzmann
James V
JV
Redmond
Eileen M
EM
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology*; D002417:Cattle; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000096:biosynthesis / Q000502:physiology; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D010446:Peptide Fragments / Q000235:genetics / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology; D011994:Recombinant Proteins; D012039:Regional Blood Flow / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D013314:Stress, Mechanical; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; D017868:Cyclic AMP-Dependent Protein Kinases; C114043:BARKct protein, recombinant; D019204:GTP-Binding Proteins; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go