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Updated: Jun 1, 2026
Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Decreased sarcolipin protein expression and enhanced sarco(endo)plasmic reticulum Ca2+ uptake in human atrial
Mayilvahanan Shanmugam1, Cristina E Molina, Shumin Gao
1Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 165 South Orange Ave, MSB G609, Newark, NJ 07003, USA.
Abstract:
Sarcolipin (SLN), a key regulator of cardiac sarco(endo)plasmic reticulum (SR) Ca(2+) ATPase, is predominantly expressed in atria and mediates β-adrenergic responses. Studies have shown that SLN mRNA expression is decreased in human chronic atrial fibrillation (AF) and in aortic banded mouse atria; however, SLN protein expression in human atrial pathology and its role in atrial SR Ca(2+) uptake are not yet elucidated. In the present study, we determined the expression of major SR Ca(2+) handling proteins in atria of human AF patients and in human and in a mouse model of heart failure (HF). We found that the expression of SR Ca(2+) uptake and Ca(2+) release channel proteins are significantly decreased in atria but not in the ventricles of pressure-overload induced HF in mice. In human AF and HF, the expression of SLN protein was significantly decreased; whereas the expressions of other major SR Ca(2+) handling proteins were not altered. Further, we found that the SR Ca(2+) uptake was significantly increased in human AF. The selective downregulation of SLN and enhanced SR Ca(2+) uptake in human AF suggest that SLN downregulation could play an important role in abnormal intracellular Ca(2+) cycling in atrial pathology.
