TRPC3 cation channel plays an important role in proliferation and differentiation of skeletal muscle myoblasts.
During membrane depolarization associated with skeletal excitation-contraction (EC) coupling, dihydropyridine receptor [DHPR, a L-type Ca(2+) channel in the transverse (t)-tubule membrane] undergoes conformational changes that are transmitted to ryanodine receptor 1 [RyR1, an internal Ca(2+)-release channel in the sarcoplasmic reticulum (SR) membrane] causing Ca(2+) release from the SR. Canonical-type transient receptor potential cation channel 3 (TRPC3), an extracellular Ca(2+)-entry channel in the t-tubule and plasma membrane, is required for full-gain of skeletal EC coupling. To examine additional role(s) for TRPC3 in skeletal muscle other than mediation of EC coupling, in the present study, we created a stable myoblast line with reduced TRPC3 expression and without alpha1((S))DHPR (MDG/TRPC3 KD myoblast) by knock-down of TRPC3 in alpha1((S))DHPR-null muscular dysgenic (MDG) myoblasts using retrovirus-delivered small interference RNAs in order to eliminate any DHPR-associated EC coupling-related events. Unlike wild-type or alpha1((S))DHPR-null MDG myoblasts, MDG/TRPC3 KD myoblasts exhibited dramatic changes in cellular morphology (e.g., unusual expansion of both cell volume and the plasma membrane, and multi-nuclei) and failed to differentiate into myotubes possibly due to increased Ca(2+) content in the SR. These results suggest that TRPC3 plays an important role in the maintenance of skeletal muscle myoblasts and myotubes.
Woo
Jin Seok
JS
Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
Cho
Chung-Hyun
CH
Kim
Do Han
DH
Lee
Eun Hui
EH
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism; D002412:Cations / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D056966:Excitation Contraction Coupling; D055785:Gene Knockdown Techniques; D008564:Membrane Potentials; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism; D032448:Myoblasts, Skeletal / Q000378:metabolism*; D000071740:ORAI1 Protein; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000502:physiology*; D016708:Synaptophysin / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D050051:Transient Receptor Potential Channels / Q000378:metabolism
D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D002412:Cations; C111842:Mg29 protein, mouse; D009124:Muscle Proteins; D000071740:ORAI1 Protein; C520430:Orai1 protein, mouse; D019837:Ryanodine Receptor Calcium Release Channel; D016708:Synaptophysin; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; C489571:TRPC4 ion channel; D050051:Transient Receptor Potential Channels; D002118:Calcium