An adrenal β-arrestin 1-mediated signaling pathway underlies angiotensin II-induced aldosterone production in vitro and in vivo
Abstract
Aldosterone produces a multitude of effects in vivo, including promotion of postmyocardial infarction adverse cardiac remodeling and heart failure progression. It is produced and secreted by the adrenocortical zona glomerulosa (AZG) cells after angiotensin II (AngII) activation of AngII type 1 receptors (AT1Rs). Until now, the general consensus for AngII signaling to aldosterone production has been that it proceeds via activation of Gq/11-proteins, to which the AT1R normally couples. Here, we describe a novel signaling pathway underlying this AT1R-dependent aldosterone production mediated by β-arrestin-1 (βarr1), a universal heptahelical receptor adapter/scaffolding protein. This pathway results in sustained ERK activation and subsequent up-regulation of steroidogenic acute regulatory protein, a steroid transport protein regulating aldosterone biosynthesis in AZG cells. Also, this βarr1-mediated pathway appears capable of promoting aldosterone turnover independently of G protein activation, because treatment of AZG cells with SII, an AngII analog that induces βarr, but not G protein coupling to the AT1R, recapitulates the effects of AngII on aldosterone production and secretion. In vivo, increased adrenal βarr1 activity, by means of adrenal-targeted adenoviral-mediated gene delivery of a βarr1 transgene, resulted in a marked elevation of circulating aldosterone levels in otherwise normal animals, suggesting that this adrenocortical βarr1-mediated signaling pathway is operative, and promotes aldosterone production and secretion in vivo, as well. Thus, inhibition of adrenal βarr1 activity on AT1Rs might be of therapeutic value in pathological conditions characterized and aggravated by hyperaldosteronism.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- April 2009
- DOI:
- 10.1073/pnas.0811706106
- Bibcode:
- 2009PNAS..106.5825L
- Keywords:
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- adrenocortical zona glomerulosa cell;
- G protein-coupled receptor;
- angiotensin II receptor type I;
- adrenal steroid hormones;
- biased agonism;
- Biological Sciences:Medical Sciences