TRPC6 fulfills a calcineurin signaling circuit during pathologic cardiac remodeling
Koichiro Kuwahara, … , Joseph A. Hill, Eric N. Olson
Koichiro Kuwahara, … , Joseph A. Hill, Eric N. Olson
Published December 1, 2006
Citation Information: J Clin Invest. 2006;116(12):3114-3126. https://doi.org/10.1172/JCI27702.
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Research Article Cardiology

TRPC6 fulfills a calcineurin signaling circuit during pathologic cardiac remodeling

Abstract

The heart responds to injury and chronic pressure overload by pathologic growth and remodeling, which frequently result in heart failure and sudden death. Calcium-dependent signaling pathways promote cardiac growth and associated changes in gene expression in response to stress. The calcium/calmodulin-dependent phosphatase calcineurin, which signals to nuclear factor of activated T cells (NFAT) transcription factors, serves as a transducer of calcium signals and is sufficient and necessary for pathologic cardiac hypertrophy and remodeling. Transient receptor potential (TRP) proteins regulate cation entry into cells in response to a variety of signals, and in skeletal muscle, expression of TRP cation channel, subfamily C, member 3 (TRPC3) is increased in response to neurostimulation and calcineurin signaling. Here we show that TRPC6 was upregulated in mouse hearts in response to activated calcineurin and pressure overload, as well as in failing human hearts. Two conserved NFAT consensus sites in the promoter of the TRPC6 gene conferred responsiveness to cardiac stress. Cardiac-specific overexpression of TRPC6 in transgenic mice resulted in heightened sensitivity to stress, a propensity for lethal cardiac growth and heart failure, and an increase in NFAT-dependent expression of β–myosin heavy chain, a sensitive marker for pathologic hypertrophy. These findings implicate TRPC6 as a positive regulator of calcineurin-NFAT signaling and a key component of a calcium-dependent regulatory loop that drives pathologic cardiac remodeling.

Authors

Koichiro Kuwahara, Yanggan Wang, John McAnally, James A. Richardson, Rhonda Bassel-Duby, Joseph A. Hill, Eric N. Olson

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Figure 2

The calcineurin-NFAT pathway regulates Trpc6 gene transcription.

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The calcineurin-NFAT pathway regulates Trpc6 gene transcription. ...
(A) Schematic representation of the 5′ upstream region of the mouse Trpc6 gene. Sequences between –796 and –750 bp of the mouse Trpc6 gene are aligned with the corresponding sequences of rat Trpc6 and human TRPC6 genes. NFAT-like sites are shown in red and blue. (B) Gel mobility shift assay was performed using in vitro translated NFATc4Δ317 and 32P-labeled probes of NFAT consensus sequences or NFAT-like sites 1 or 2 from the Trpc6 promoter. (C) Rat neonatal ventricular myocytes were cotransfected with an expression plasmid of NFATc4Δ317 and –913TRPC6-luc, –617TRPC6-luc, or the Trpc6 promoter with NFAT site mutations (–913mutNFAT1-luc, –913mutNFAT2-luc, or –913mutNFAT1+2-luc). Percent increase in expression with NFATc4Δ317 compared with empty pGL3 luciferase reporter vector is shown. (D) Rat neonatal ventricular myocytes were cotransfected with a plasmid expressing CnAΔC and –913TRPC6-luc, –617TRPC6-luc, or the Trpc6 promoter with 2 NFAT site mutations. Percent increase in expression with CnAΔC compared with empty pGL3 luciferase reporter vector is shown. (E) Rat neonatal ventricular myocytes were cotransfected with either –913TRPC6 promoter region or luciferase reporter gene fused to the Trpc6 promoter with 2 NFAT site mutations in the presence or absence of 10 nM ET-1. Percent increase in luciferase expression by ET-1 with each construct is shown.