Rho/ROCK signaling and α-catenin mediate β-catenin–driven hyperplasia in the adrenal cortex via adherens junctions
Mesut Berber, Betul Haykir, Nick A. Guagliardo, Vasileios Chortis, Kleiton Silva Borges, Paula Q. Barrett, Felix Beuschlein, Diana L. Carlone, David T. Breault
Mesut Berber, Betul Haykir, Nick A. Guagliardo, Vasileios Chortis, Kleiton Silva Borges, Paula Q. Barrett, Felix Beuschlein, Diana L. Carlone, David T. Breault
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Research Article Cardiology Development Endocrinology

Rho/ROCK signaling and α-catenin mediate β-catenin–driven hyperplasia in the adrenal cortex via adherens junctions

Abstract

How β-catenin (βCat) mediates tissue hyperplasia is poorly understood. To explore this, we employed the adrenal cortex as a model system given its stereotypical spatial organization and the important role βCat plays in homeostasis and disease. For example, excessive production of aldosterone by the adrenal cortex (primary aldosteronism [PA]) is a major cause of cardiovascular morbidity and is associated with βCat gain of function (βCat-GOF). Adherens junctions (AJs) connect the actin cytoskeletons of adjacent zona glomerulosa (zG) cells via a cadherin–βCat–α-catenin complex and mediate aldosterone production. Whether βCat-GOF drives zG hyperplasia, a key feature of PA, via AJs is unknown. Here, we showed that aldosterone secretagogues (K+ and AngII) and βCat-GOF mediated AJ formation via Rho/ROCK/actomyosin signaling. In addition, Rho/ROCK inhibition led to altered zG rosette morphology and decreased aldosterone production. Mice with zG-specific βCat-GOF demonstrated increased AJ formation and zG hyperplasia, which was blunted by Rho/ROCK inhibition and deletion of α-catenin (αCat). βCat also impacted AJ formation independently of its role as a transcription factor. Furthermore, analysis of human aldosterone-producing adenomas revealed high levels of βCat expression were associated with increased membranous expression of K-cadherin. Together, our findings identified Rho/ROCK signaling and αCat as key mediators of AJ formation and βCat-driven hyperplasia.

Authors

Mesut Berber, Betul Haykir, Nick A. Guagliardo, Vasileios Chortis, Kleiton Silva Borges, Paula Q. Barrett, Felix Beuschlein, Diana L. Carlone, David T. Breault

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Figure 5

βCat stabilization strengthens AJs in the zG, while ROCK inhibition with fasudil prevents hyperplasia and reduces aldosterone production.

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βCat stabilization strengthens AJs in the zG, while ROCK inhibition with...
(A) Representative images of KCad and p120-catenin (p120) immunofluorescence in adrenal sections from 2-month-old control and βCat-GOF female mice. Schematic of Cyp11b2Cre/+:Ctnnb1fl(Ex3)/wt (βCat-GOF) mice. (B) Representative images of KCad/p120 PLA signal in sections from 2-month-old control and βCat-GOF female mice. (C) Quantification of PLA signal per zG area from control and βCat-GOF mice represented in B (n = 5, 4 mice). (D) Representative images of Dab2 immunofluorescence in sections from 2-month-old βCat-GOF female mice treated with either vehicle (PBS) or fasudil (30 mg/kg) administered every other day for 28 days. (E) Quantification of percentage Dab2+ area in the cortex, as shown in D (n = 5, 5 mice). (F) Representative images of laminin β1 immunofluorescence in sections from βCat-GOF female mice treated as in D. (G) Quantification of the 2D area of glomerular structures, as defined by laminin β1 labeling in F (n = 5, 6 mice). (H) Measurement of 24-hour urinary aldosterone (Aldo) levels of 4-month-old βCat-GOF female mice treated with either vehicle (PBS) or fasudil (30 mg/kg) administered 6 times per week for 28 days, assessed by RIA and normalized to creatinine (Creat) (n = 8, 6 mice). (I) Ren mRNA expression in kidneys of 4-month-old βCat-GOF female mice treated as in H, assessed by qPCR (n = 4, 5 mice). Data are presented as fold change relative to vehicle-treated controls normalized to Gapdh expression. (J) Schematic of control, βCat-GOF, and βCat-GOF:fasudil–treated mice. All statistical significance determined by unpaired 2-tailed Student’s t test. *P < 0.05, **P < 0.01, ***P < 0.001. Data are presented as mean ± SEM. Solid lines mark the boundary between the capsule (C) and zG, and dashed lines marks boundary between the zG and zona fasciculata (zF). Each white asterisk denotes an individual cell within a zG rosette. Scale bars: 20 μm.