Gene-trapped mouse embryonic stem cell-derived cardiac myocytes and human genetics implicate AKAP10 in heart rhythm regulation

*Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158;
^§Cardiovascular Research Institute and
Departments of ^†Medicine and
^††Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143;
^¶Department of Medicine, University of California, Los Angeles, CA 90095;
^‖Functional Genomics Laboratory, University of California, Berkeley, CA 94720; and
**Veterans Affairs Medical Center, San Francisco, CA 94143

Edited by Susan S. Taylor, University of California at San Diego, La Jolla, CA, and approved March 29, 2007 (received for review November 28, 2006)

Abstract

Sudden cardiac death due to abnormal heart rhythm kills 400,000–460,000 Americans each year. To identify genes that regulate heart rhythm, we are developing a screen that uses mouse embryonic stem cells (mESCs) with gene disruptions that can be differentiated into cardiac cells for phenotyping. Here, we show that the heterozygous disruption of the Akap10 (D-AKAP2) gene that disrupts the final 51 aa increases the contractile response of cultured cardiac cells to cholinergic signals. In both heterozygous and homozygous mutant mice derived from these mESCs, the same Akap10 disruption increases the cardiac response to cholinergic signals, suggesting a dominant interfering effect of the Akap10 mutant allele. The mutant mice have cardiac arrhythmias and die prematurely. We also found that a common variant of AKAP10 in humans (646V, 40% of alleles) was associated with increased basal heart rate and decreased heart rate variability (markers of low cholinergic/vagus nerve sensitivity). These markers predict an increased risk of sudden cardiac death. Although the molecular mechanism remains unknown, our findings in mutant mESCs, mice, and a common human AKAP10 SNP all suggest a role for AKAP10 in heart rhythm control. Our stem cell-based screen may provide a means of identifying other genes that control heart rhythm.

Footnotes

^‡‡To whom correspondence should be addressed at:
Gladstone Institute of Cardiovascular Disease, 1650 Owens Street, San Francisco, CA 94158.
E-mail: bconklin{at}gladstone.ucsf.edu
Author contributions: W.G.T. and B.R.C. designed research; W.G.T., T.K., and T.N. performed research; W.G.T., L.P., J.G.Z., T.N., K.V., P.-Y.K., M.A.W., and B.R.C. contributed new reagents/analytic tools; W.G.T., L.P., J.G.Z., T.K., T.N., S.G.Y., K.V., P.-Y.K., M.A.W., and B.R.C. analyzed data; and W.G.T., S.G.Y., K.V., and B.R.C. wrote the paper.
↵ ^‡Present address: CardioDx, 3183 Porter Drive, Palo Alto, CA 94304.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0610393104/DC1.
Abbreviations:

Akaps,

A-kinase-anchoring proteins;

AV,

atrioventricular;

βAR,

β-adrenergic receptor;

GIRK,

Gi protein-gated inwardly rectifying potassium;

HR,

heart rate;

PKA,

protein kinase A;

mAChR,

M2 cholinergic receptor;

mESC,

mouse embryonic stem cell;

RGS,

regulator of G protein signaling.
Freely available online through the PNAS open access option.