Myosin light chain kinase controls voltage-dependent calcium channels in vascular smooth muscle

• Published in: Pflügers Archiv Vol. 466; no. 7; pp. 1377 - 1389
• Main Authors: Martinsen, A., Schakman, O., Yerna, X., Dessy, C., Morel, N.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2014; Springer Nature B.V
• Subjects: Animals; Arginine Vasopressin - pharmacology; Biomedical and Life Sciences; Biomedicine; Calcium - metabolism; Calcium Channels, L-Type - genetics; Calcium Channels, L-Type - metabolism; Calcium Channels, T-Type - genetics; Calcium Channels, T-Type - metabolism; Cell Biology; Cell Line; Human Physiology; Ion Channels; Male; Molecular Medicine; Muscle Contraction; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Muscle, Smooth, Vascular - physiology; Myosin-Light-Chain Kinase - genetics; Myosin-Light-Chain Kinase - metabolism; Neurosciences; Norepinephrine - pharmacology; Potassium Chloride - pharmacology; Rats; Rats, Wistar; Receptors; Receptors and Transporters; RNA, Messenger - genetics; RNA, Messenger - metabolism; Vasoconstriction; Voltage-dependent calcium channels; Resistance mesenteric artery; Myosin light chain kinase; A7r5
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/s00424-013-1380-3

The Ca 2+ -dependent kinase myosin light chain kinase (MLCK) is the activator of smooth muscle contraction. In addition, it has been reported to be involved in Ca 2+ channel regulation in cultured cells, and we previously showed that the MLCK inhibitor ML-7 decreases arginine vasopressin (AVP)-induced Ca 2+ influx in rat aorta. This study was designed to investigate whether MLCK is involved in Ca 2+ regulation in resistance artery smooth muscle cell, which plays a major role in the control of blood pressure. As ML compounds were shown to have off-target effects, MLCK was downregulated by transfection with a small interfering RNA targeting MLCK (MLCK-siRNA) in rat small resistance mesenteric artery (RMA) and in the rat embryonic aortic cell line A7r5. Noradrenaline-induced contraction and Ca 2+ signal were significantly depressed in MLCK-siRNA compared to scramble-siRNA-transfected RMA. Contraction and Ca 2+ signal induced by high KCl and voltage-activated Ca 2+ current were also significantly decreased in MLCK-siRNA-transfected RMA, suggesting that MLCK depletion modifies voltage-operated Ca 2+ channels. KCl- and AVP-induced Ca 2+ signals and voltage-activated Ca 2+ current were decreased in MLCK-depleted A7r5 cells. Eventually, real-time quantitative PCR analysis indicated that in A7r5, MLCK controlled mRNA expression of Ca V 1.2 (L-type) and Ca V 3.1 (T-type) voltage-dependent Ca 2+ channels. Our results suggest that MLCK controls the transcription of voltage-dependent Ca 2+ channels in vascular smooth muscle cells.