Specific Upregulation of TRPC1 and TRPC5 Channels by Mineralocorticoid Pathway in Adult Rat Ventricular Cardiomyocytes.

Fiona Bartoli,Soraya Moradi Bachiller,Kaveen Bedouet,Jessica Sabourin,Fabrice Antigny,Pascale Gerbaud,Jean-Pierre Benitah

doi:10.3390/cells9010047

Abstract

Whereas cardiac TRPC (transient receptor potential canonical) channels and the associated store-operated Ca2+ entry (SOCE) are abnormally elevated during cardiac hypertrophy and heart failure, the mechanism of this upregulation is not fully elucidated but might be related to the activation of the mineralocorticoid pathway. Using a combination of biochemical, Ca2+ imaging, and electrophysiological techniques, we determined the effect of 24-h aldosterone treatment on the TRPCs/Orai-dependent SOCE in adult rat ventricular cardiomyocytes (ARVMs). The 24-h aldosterone treatment (from 100 nM to 1 µM) enhanced depletion-induced Ca2+ entry in ARVMs, as assessed by a faster reduction of Fura-2 fluorescence decay upon the addition of Mn2+ and increased Fluo-4/AM fluorescence following Ca2+ store depletion. These effects were prevented by co-treatment with a specific mineralocorticoid receptor (MR) antagonist, RU-28318, and they are associated with the enhanced depletion-induced N-[4-[3,5-Bis(trifluoromethyl)-1H-pyrazol-1-yl]phenyl]-4-methyl-1,2,3-thiadiazole-5-carboxamide (BTP2)-sensitive macroscopic current recorded by patch-clamp experiments. Molecular screening by qRT-PCR and Western blot showed a specific upregulation of TRPC1, TRPC5, and STIM1 expression at the messenger RNA (mRNA) and protein levels upon 24-h aldosterone treatment of ARVMs, corroborated by immunostaining. Our study provides evidence that the mineralocorticoid pathway specifically promotes TRPC1/TRPC5-mediated SOCE in adult rat cardiomyocytes.

Highlights

The physiological impact of store-operated Ca2+ entry (SOCE) in adult cardiomyocytes is still under debate, notably due to low-to-moderate expression of their molecular constituents including the molecular complex of STIM1 with Orai1 channels and with different isoforms of transient receptor potential canonical channels (TRPCs; notably 1, 4, and 5) [1,2,3,4,5]
Our study was aimed at investigating the aldosterone effect on SOCE in adult rat ventricular cardiomyocytes (ARVMs)
Our results indicate that a 24-h treatment of high-dose aldosterone stimulates the SOCE in an mineralocorticoid receptor (MR)-dependent manner, due to a specific upregulation of TRPC1, TRPC5, and STIM1

Summary

Introduction

The physiological impact of store-operated Ca2+ entry (SOCE) in adult cardiomyocytes is still under debate, notably due to low-to-moderate expression of their molecular constituents including the molecular complex of STIM1 with Orai channels and with different isoforms of transient receptor potential canonical channels (TRPCs; notably 1, 4, and 5) [1,2,3,4,5]. Cells 2020, 9, 47 proposed that the upregulation of cardiac SOCE during pathological growth is part of the fetal gene program [4,17], neuroendocrine factors, which underpin the pathogenesis of heart failure and trigger. Cardiomyocytes express the MR, a ligand-dependent transcription factor interacting with the glucocorticoid-responsive elements of target genes, whose activity might control Ca2+ homeostasis on the target cells [19,20,21]. Prior studies suggested that stimulation of neonatal rat ventricular myocytes (NRVMs) or human embryonic stem-cell-derived cardiomyocytes with angiotensin II, phenylephrine, endothelin-1, or aldosterone evoked an exacerbated SOCE, correlating with increased expression of Orai, TRPC1, TRPC4, and/or

Methods

Results

Conclusion