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(Circulation Research. 2009;105:1023.)
© 2009 American Heart Association, Inc.

Integrative Physiology

TRPC1 Channels Are Critical for Hypertrophic Signaling in the Heart

Malini Seth, Zhu-Shan Zhang, Lan Mao, Victoria Graham, Jarrett Burch, Jonathan Stiber, Leonidas Tsiokas, Michelle Winn, Joel Abramowitz, Howard A. Rockman, Lutz Birnbaumer, Paul Rosenberg

From the Department of Medicine (M.S., Z.-S.Z., L.M., V.G., J.B., J.S., M.W., H.A.R., P.R.), Duke University School of Medicine, Durham, NC; Department of Cell Biology (L.T.), University of Oklahoma Health Sciences Center, Oklahoma City; and Laboratory of Neurobiology (J.A., L.B.), National Institute of Environmental Health Sciences, Research Triangle Park, NC.

Correspondence to Paul Rosenberg, Suite 200, 4321 Medical Park Dr, Durham, NC 27704. E-mail rosen029{at}mc.duke.edu

Rationale: Cardiac muscle adapts to increase workload by altering cardiomyocyte size and function resulting in cardiac hypertrophy. G protein–coupled receptor signaling is known to govern the hypertrophic response through the regulation of ion channel activity and downstream signaling in failing cardiomyocytes.

Objective: Transient receptor potential canonical (TRPC) channels are G protein–coupled receptor operated channels previously implicated in cardiac hypertrophy. Our objective of this study is to better understand how TRPC channels influence cardiomyocyte calcium signaling.

Methods and Results: Here, we used whole cell patch clamp of adult cardiomyocytes to show upregulation of a nonselective cation current reminiscent of TRPC channels subjected to pressure overload. This TRPC current corresponds to the increased TRPC channel expression noted in hearts of mice subjected to pressure overload. Importantly, we show that mice lacking TRPC1 channels are missing this putative TRPC current. Moreover, Trpc1^–/– mice fail to manifest evidence of maladaptive cardiac hypertrophy and maintain preserved cardiac function when subjected to hemodynamic stress and neurohormonal excess. In addition, we provide a mechanistic basis for the protection conferred to Trpc1^–/– mice as mechanosensitive signaling through calcineurin/NFAT, mTOR and Akt is altered in Trpc1^–/– mice.

Conclusions: From these studies, we suggest that TRPC1 channels are critical for the adaptation to biomechanical stress and TRPC dysregulation leads to maladaptive cardiac hypertrophy and failure.

Key Words: transient receptor potential channels • G protein receptor signaling • cardiac hypertrophy