Two-pore domain potassium (K2P) channels influence basic cellular parameters such as resting membrane potential, cellular excitability or intracellular Ca2+-concentration [Ca2+]i. While the physiological importance of K2P-channels in dif-ferent organ systems (e.g. heart, CNS or immune system) has become increas-ingly clear over the last decade, their expression profile and functional role in skeletal muscle cells (SkMC) remains largely unknown. The mouse SkMC cell line C2C12, wild type mouse muscle tissue and primary mouse muscle cells (PMM) were analyzed using quantitative PCR, western blotting and immuno-histochemical stainings as well as functional analysis including patch-clamp measurements and Ca2+-imaging. Mouse SkMC express TASK2, TREK1, TREK2 and TRAAK. Except TASK2 all mentioned channels were upregulated in vitro during differentiation from myoblasts to myotubes. TASK2 and TREK1 were also functionally expressed and upregulated in PMMs isolated from mouse muscle tissue. Inhibition of TASK2 and TREK1 during differentiation revealed a morphological impairment of myoblast fusion accompanied by a downregulation of maturation markers. TASK2 and TREK1 blockade led to a decreased K+ out-ward current and a decrease of ACh-dependent Ca2+-influx in C2C12 cells as potential underlying mechanism. K2P-channel expression was also detected in human muscle tissue by immunohistochemistry pointing towards possible rele-vance for human muscle cell maturation and function. In conclusion, our find-ings for the first time demonstrate the functional expression of TASK2 and TREK1 in muscle cells with implications for differentiation processes warranting further investigations in physiologic and pathophysiologic scenarios.
- Muscle cells
- Copyright © 2016, American Journal of Physiology-Cell Physiology