Submitted on August 6, 2007
Accepted on December 14, 2007
Genes Over-expressed in Cerebral Arteries Following Salt-induced Hypertensive Disease are Regulated by Angiotensin II, JunB and CREB
Patricia Rose1, Jeffrey Bond2, Scott Tighe3, Michael J Toth4, Theresa L. Wellman1, Eva Maria Briso de Montiano1, Martin M. LeWinter4, and Karen M Lounsbury5*
1 Pharmacology, University of Vermont, Burlington, Vermont, United States
2 Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States
3 Vermont Cancer Center, University of Vermont, Burlington, Vermont, United States
4 Medicine, University of Vermont, Burlington, Vermont, United States
5 Pharmacology, University of Vermont, Burlington, United States
* To whom correspondence should be addressed. E-mail: karen.lounsbury{at}uvm.edu.
Although changes in gene expression are necessary for arterial remodeling during hypertension, the genes altered and their mechanisms of regulation remain uncertain. The goal of this study was to identify cerebral artery genes altered by hypertension and define signaling pathways important in their regulation. Intact cerebral arteries from Dahl salt-sensitive normotensive (LS) and hypertensive (HS) rats were examined by immunostaining, revealing increased phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) and expression of the proliferative marker, Ki-67 in arteries from hypertensive animals. Arterial RNA analyzed by microarray and validated with RT-qPCR revealed that jun-family member, junB, and matricellular genes, plasminogen activator inhibitor-1 (PAI-1) and osteopontin (OPN), were significantly over-expressed in HS arteries. Fisher’s exact test and annotation-based gene subsets showed that genes upregulated by Jun and Ca2+/cAMP-response element binding protein (CREB) were over-represented. A model of cultured rat cerebrovascular smooth muscle cells was used to test the hypothesis that Angiotensin II (Ang II), JunB and CREB are important in the regulation of genes identified in the rat hypertension model. Ang II induced transient induction of junB and delayed induction of PAI-1 and OPN mRNA levels that were reduced by ERK inhibition with U0126. Silencing junB using siRNA reduced mRNA levels of OPN, but not PAI-1. Silencing of CREB reduced PAI-1 induction by Ang II, but enhanced transcription of OPN. Together these results suggest that salt induced hypertensive disease promotes changes in matricellular genes that are stimulated by Ang II, regulated by ERK, and selectively regulated by JunB and CREB.
