Viral-mediated gene delivery of constitutively activated G alpha s alters vasoreactivity.
1. Decline in beta-adrenoceptor (beta-AR)-mediated function occurs with increasing age, as well as in multiple disease conditions. The mechanisms responsible for this decline include alterations in beta-AR itself, beta-AR coupling proteins, such as G-proteins, or other beta-AR-linked proteins, such as G-protein receptor kinases and/or phosphatases. 2. The present study examines the physiological effects of in vitro transfer of constitutively activated G alpha s (G alpha s-Q227L) to both cultured vascular smooth muscle cells (VSMC) and whole aortic tissue of 6-month-old (adult) animals via a replication-deficient Herpes simplex virus (HSV) vector. These studies were conducted to provide a model for future examination of the role of G alpha s in the age-related decline in beta-AR-mediated vasorelaxation. 3. Gene transfer was confirmed by western blotting for specific proteins. Aortic tissue infected with HSV-G alpha s-Q227L had reduced phenylephrine-induced contraction and enhanced isoproterenol-stimulated vasorelaxation. Infection of cultured VSMC with HSV-G alpha s-Q227L increased both basal- and isoproterenol-stimulated cAMP accumulation, whereas forskolin-stimulated cAMP production was unchanged. 4. These results implicate G alpha s as a target for further investigation in age-related changes in vascular reactivity and support the use of viral-mediated gene transfer as an effective tool to study adrenergic signal transduction and physiology in vascular tissue.
Schutzer
W E
WE
Portland VA Medical Center, Research Service, Oregon, USA.
Watts
V J
VJ
Chapman
J
J
Cumbay
M G
MG
Neve
K A
KA
Neve
R L
RL
Mader
S L
SL
D000818:Animals; D001011:Aorta / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D018139:Simplexvirus / Q000235:genetics; D014664:Vasodilation / Q000235:genetics / Q000502:physiology*
D000242:Cyclic AMP; D019204:GTP-Binding Proteins