The classic view of angiotensin II (All), the primary biologically active component through which the renin angiotensin system mediates hemodynamic and electrolyte effects, is that it functions as a blood-borne hormone. In the last decade, it has become increasingly clear that All can be generated in tissues, act as a local hormone, and confer autocrine and/or paracrine effects. Our published studies show that expression of intracellular All stimulates cell growth and that the growth stimulation is accompanied by cAMP response element-binding protein (CREB) phosphorylation and PDGF A-chain upregulation. We now propose to extend these studies to generate mice transgenic for two different expression cassettes directing intracellular AII production. In addition, we will cross the transgenic mice with null-Aogen mice to determine whether intracellular expression of Aogen (angiotensinogen) and subsequent intracellular generation of All can compensate for an absence of extracellular All and, thus, reverse the kidney and blood pressure phenotypes of the knockout mice. These studies will apply a cDNA construct which we have designed to encode a form of Aogen, devoid of the signal sequence (which directs secretion), but possessing an intact AI/AII-encoding region. This modified Aogen is growth stimulatory for H4-II-E-C3 rat hepatoma cells. These studies will likewise apply an intracellular fluorescent fusion protein of All that we have shown to stimulate growth and CREB phosphorylation in cells expressing AT1 receptor fusion proteins. Both exogenous All and intracellular All induce AT 1R trafficking to cell nuclei; the receptor trafficking pathway for each will be established. We will identify and compare kinase pathways responsible for CREB phosphorylation following intracellular versus extracellular All stimulation. Collectively, these studies will define the relative roles and relative importance of intracellular and extracellular All, and the potential for internalization or intracellular generation of All in vivo in unmanipulated systems.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL072795-01A2
Application #
6923237
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
Lin, Michael
Project Start
2005-03-01
Project End
2010-02-28
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
1
Fiscal Year
2005
Total Cost
$285,000
Indirect Cost
Name
Ochsner Clinic Foundation
Department
Type
DUNS #
077900207
City
New Orleans
State
LA
Country
United States
Zip Code
70121
Vitko, Jason R; Re, Richard N; Alam, Jawed et al. (2012) Cell-penetrating peptides corresponding to the angiotensin II Type 1 receptor reduce receptor accumulation and cell surface expression and signaling. Am J Hypertens 25:24-8
Cook, Julia L; Re, Richard N (2012) Lessons from in vitro studies and a related intracellular angiotensin II transgenic mouse model. Am J Physiol Regul Integr Comp Physiol 302:R482-93
Li, Xiao C; Cook, Julia L; Rubera, Isabelle et al. (2011) Intrarenal transfer of an intracellular fluorescent fusion of angiotensin II selectively in proximal tubules increases blood pressure in rats and mice. Am J Physiol Renal Physiol 300:F1076-88
Cook, Julia L; Singh, Akannsha; DeHaro, Dawn et al. (2011) Expression of a naturally occurring angiotensin AT(1) receptor cleavage fragment elicits caspase-activation and apoptosis. Am J Physiol Cell Physiol 301:C1175-85
Re, Richard N; Cook, Julia L (2011) Noncanonical intracrine action. J Am Soc Hypertens 5:435-48
Alam, Jawed; Deharo, Dawn; Redding, Kevin M et al. (2010) C-terminal processing of GABARAP is not required for trafficking of the angiotensin II type 1A receptor. Regul Pept 159:78-86
Redding, K M; Chen, B L; Singh, A et al. (2010) Transgenic mice expressing an intracellular fluorescent fusion of angiotensin II demonstrate renal thrombotic microangiopathy and elevated blood pressure. Am J Physiol Heart Circ Physiol 298:H1807-18
Re, Richard N; Cook, Julia L (2010) The mitochondrial component of intracrine action. Am J Physiol Heart Circ Physiol 299:H577-83
Cook, Julia L (2010) G protein-coupled receptors as disease targets: emerging paradigms. Ochsner J 10:2-7
Re, Richard N; Cook, Julia L (2009) Senescence, apoptosis, and stem cell biology: the rationale for an expanded view of intracrine action. Am J Physiol Heart Circ Physiol 297:H893-901

Showing the most recent 10 out of 18 publications