title: Adenovirus-mediated small-interference RNA for in vivo silencing of angiotensin AT1a receptors in mouse brain.
abstract: Because of the lack of pharmacological approaches, molecular genetic methods have been required to differentiate between angiotensin type 1(AT1) receptor subtypes AT1a and AT1b. RNA interference is a new tool for the study of gene function, producing specific downregulation of protein expression. In this study, we used the small hairpin RNA (shRNA) cassette method to screen target sites for selectively silencing AT1a or AT1b receptor subtypes in cultured Neuro-2a cells using real-time RT-PCR. For in vivo functional studies, we used C57BL mice with arterial telemetric probes and computerized licking monitors to test the effect of adenovirus carrying the DNA sequence coding AT1a shRNA (Ad-AT1a-shRNA). Ad-AT1a-shRNA was injected into the lateral ventricle (intracerebroventricular) or the brain stem nucleus tractus solitaries/dorsal vagal nucleus (NTS/DVN) with measurement of water intake, blood pressure (BP), and heart rate (HR) for up to 20 days after injection. Tissue culture studies verified the specificity and the efficiency of the constructs. In animal studies, beta-galactosidase staining and Ang receptor binding assays showed expression of shRNA and downregulation of Ang AT1 receptors in the subfornical organ and NTS/DVN by >70%. Intracerebroventricular injection of Ad-AT1a-shRNA increased water intake with no effect on BP or HR. In contrast, microinjection of Ad-AT1a-shRNA into NTS/DVN caused a decrease in BP with no effect on HR or water intake. Results demonstrate the use of the RNA interference method in site-directed silencing of gene expression and provide a method for the in vivo study of Ang AT1 receptor function.
authors.affiliation: Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH 45435, USA. yanfang.chen@wright.edu
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Andrea
authors.initials: A
authors.lastname: Hoffmann
authors.forename: David R
authors.initials: DR
authors.lastname: Cool
authors.forename: Debra I
authors.initials: DI
authors.lastname: Diz
authors.forename: Mark C
authors.initials: MC
authors.lastname: Chappell
authors.forename: Alex F
authors.initials: AF
authors.lastname: Chen
authors.forename: Alex
authors.initials: A
authors.lastname: Chen
authors.forename: Mariana
authors.initials: M
authors.lastname: Morris
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002460:Cell Line; D003199:Computer Systems; D015536:Down-Regulation; D004326:Drinking / Q000187:drug effects; D020868:Gene Silencing; D005822:Genetic Vectors; D007276:Injections, Intraventricular; D020547:Lateral Ventricles; D051379:Mice; D008810:Mice, Inbred C57BL; D008845:Microinjections; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000494:pharmacology; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017552:Solitary Nucleus / Q000378:metabolism; D013356:Subfornical Organ / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D044140:Receptor, Angiotensin, Type 1