Alpha1-Adrenergic receptors (alpha1-AR) play an important role in mediating the effects of catecholamines on the physiology, phenotype and growth of vascular smooth muscle cells (VSMC). We recently found that agonist-induced down-regulation of alpha1B-AR mRNA in VSMC from the rabbit aorta (RbSMC) is due to a post-transcriptional, protein kinase C-mediated decrease in the mRNA stability. Three subtypes of the alpha1-AR (alpha1B, alpha1C and alpha1D) have been cloned, and appear to be heterogeneous with regard to tissue distribution and coupling to second messengers and physiologic responses. There is uncertainty about the relationship between the 3 cloned subtypes and pharmacologically-defined subtypes, and there is no information about the role of the alpha1-AR subtypes in mediating the effects of alpha-adrenergic agonists on growth in VSMC. The goals of this proposal are: 1) to identify the cis-elements that determine the susceptibility of alpha1B-AR mRNA to phorbol ester-induced destabilization, 2) to demonstrate and characterize a phorbol ester- stimulated binding factor for alpha1B-AR mRNA, and 3) to elucidate the coupling of the cloned alpha1B and alpha1C-AR subtypes to second messengers and growth in VSMC.
In SPECIFIC AIM I we will test the hypothesis that phorbol ester-induced destabilization of alpha1B-AR mRNA requires the presence of cis-acting structural element(s) in the mRNA by testing for the ability of phorbol esters to destabilize wild-type and modified alpha1B-AR mRNA transcripts expressed in cultured cells.
In SPECIFIC AIM II we will test the hypothesis that alpha1B-AR mRNA is destabilized by the phorbol ester-induced binding of a cell-specific, trans-acting factor by using RNA gel shift and ultraviolet cross-linking assays to demonstrate phorbol ester-induced binding of a factor in RbSMC cytosol to in vitro-transcribed rabbit alpha1B-AR mRNA. In SPECIFIC III we will use both pharmacologic methods and subtype-specific antisense oligonucleotides directed against alpha1B and alpha1C-AR mRNA to test the hypothesis that these alpha1-AR subtypes are coupled to distinct second messenger pathways and exert cooperate effects on VSMC growth (protein and DNA synthesis) and growth-related signalling pathways (activation of mitogen-activated protein kinase, and induction of c-fos and transforming growth factor-beta1 mRNAs).

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL042539-09
Application #
2901119
Study Section
Pharmacology A Study Section (PHRA)
Project Start
1989-04-26
Project End
2001-03-31
Budget Start
1999-04-26
Budget End
2000-03-31
Support Year
9
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Boston University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Trueblood, Nathan A; Inscore, Patrick R; Brenner, Daniel et al. (2005) Biphasic temporal pattern in exercise capacity after myocardial infarction in the rat: relationship to left ventricular remodeling. Am J Physiol Heart Circ Physiol 288:H244-9
Communal, Catherine; Singh, Mahipal; Menon, Bindu et al. (2003) beta1 integrins expression in adult rat ventricular myocytes and its role in the regulation of beta-adrenergic receptor-stimulated apoptosis. J Cell Biochem 89:381-8
Communal, Catherine; Colucci, Wilson S; Remondino, Andrea et al. (2002) Reciprocal modulation of mitogen-activated protein kinases and mitogen-activated protein kinase phosphatase 1 and 2 in failing human myocardium. J Card Fail 8:86-92
Xiao, Lei; Pimentel, David R; Wang, Jing et al. (2002) Role of reactive oxygen species and NAD(P)H oxidase in alpha(1)-adrenoceptor signaling in adult rat cardiac myocytes. Am J Physiol Cell Physiol 282:C926-34
Podesser, B K; Siwik, D A; Eberli, F R et al. (2001) ET(A)-receptor blockade prevents matrix metalloproteinase activation late postmyocardial infarction in the rat. Am J Physiol Heart Circ Physiol 280:H984-91
Singh, K; Xiao, L; Remondino, A et al. (2001) Adrenergic regulation of cardiac myocyte apoptosis. J Cell Physiol 189:257-65
Trueblood, N A; Xie, Z; Communal, C et al. (2001) Exaggerated left ventricular dilation and reduced collagen deposition after myocardial infarction in mice lacking osteopontin. Circ Res 88:1080-7
Xiao, L; Pimental, D R; Amin, J K et al. (2001) MEK1/2-ERK1/2 mediates alpha1-adrenergic receptor-stimulated hypertrophy in adult rat ventricular myocytes. J Mol Cell Cardiol 33:779-87
Xie, Z; Pimental, D R; Lohan, S et al. (2001) Regulation of angiotensin II-stimulated osteopontin expression in cardiac microvascular endothelial cells: role of p42/44 mitogen-activated protein kinase and reactive oxygen species. J Cell Physiol 188:132-8
Siwik, D A; Pagano, P J; Colucci, W S (2001) Oxidative stress regulates collagen synthesis and matrix metalloproteinase activity in cardiac fibroblasts. Am J Physiol Cell Physiol 280:C53-60

Showing the most recent 10 out of 43 publications