Gain-of-function mutant of angiotensin II receptor, type 1A, causes hypertension and cardiovascular fibrosis in mice
Sandrine Billet, … , Pierre Corvol, Eric Clauser
Sandrine Billet, … , Pierre Corvol, Eric Clauser
Published July 2, 2007
Citation Information: J Clin Invest. 2007;117(7):1914-1925. https://doi.org/10.1172/JCI28764.
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Research Article Cardiology

Gain-of-function mutant of angiotensin II receptor, type 1A, causes hypertension and cardiovascular fibrosis in mice

Abstract

The role of the renin-angiotensin system has been investigated by overexpression or inactivation of its different genes in animals. However, there is no data concerning the effect of the constitutive activation of any component of the system. A knockin mouse model has been constructed with a gain-of-function mutant of the Ang II receptor, type 1A (AT1A), associating a constitutively activating mutation (N111S) with a C-terminal deletion, which impairs receptor internalization and desensitization. In vivo consequences of this mutant receptor expression in homozygous mice recapitulate its in vitro characteristics: the pressor response is more sensitive to Ang II and longer lasting. These mice present with a moderate (~20 mmHg) and stable increase in BP. They also develop early and progressive renal fibrosis and cardiac fibrosis and diastolic dysfunction. However, there was no overt cardiac hypertrophy. The hormonal parameters (low-renin and inappropriately normal aldosterone productions) mimic those of low-renin human hypertension. This new model reveals that a constitutive activation of AT1A leads to cardiac and renal fibrosis in spite of a modest effect on BP and will be useful for investigating the role of Ang II in target organs in a model similar to some forms of human hypertension.

Authors

Sandrine Billet, Sabine Bardin, Sonia Verp, Véronique Baudrie, Annie Michaud, Sophie Conchon, Martine Muffat-Joly, Brigitte Escoubet, Evelyne Souil, Ghislaine Hamard, Kenneth E. Bernstein, Jean Marie Gasc, Jean-Luc Elghozi, Pierre Corvol, Eric Clauser

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Figure 1

Targeted knockin of the Agtr1a gene by homologous recombination into ES cells and mouse.

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Targeted knockin of the Agtr1a gene by homologous recombination into ES ...
(A) Schematic representation of the targeting vector and partial restriction map of the Agtr1a gene locus before and after homologous recombination. The top line shows the structure of AT1AWT locus containing exon 3 of the gene with coding sequence (black box) and the 5′ and 3′ untranslated sequences (gray boxes). Exon 3 is flanked by 3 kb of intron 2 (upstream) and 2 kb of noncoding sequence (downstream). The targeting construct containing AT1AMUT and a hygromycin cassette (hygro) was used to replace the WT BamHI (B) KpnI (K) fragment within AT1A locus (middle line). The lower line shows the targeted AT1A locus with the internal probe (probe 1) and 3′ external probe (probe 2) used for Southern blot analysis. (B) Southern blot analysis of targeted ES cell DNA using internal probe 1 with SpeI digestion (left) and using probe 2 with SacI digestion (right). C, control (targeting construct). –/–, WT cells; +/–, heterozygous recombinant cells. (C) Southern blot analysis of tail DNA samples from F2 offspring (generated by crossing heterozygous mice from the first generation [F1 mice]) digested with SacI and probed with the 3′ external probe (probe 2). –/–, WT mice; +/–, heterozygous transgenic mice; +/+, homozygous transgenic mice; S, SpeI; B, BamHI; G, BglII; X, XbaI; A, SacI; K, KpnI; N, NotI; E, EcoRI.