Sphingosine 1-phosphate increases an intracellular Ca(2+) concentration via S1P3 receptor in cultured vascular smooth muscle cells

• Published in: Journal of pharmacy and pharmacology Vol. 66; no. 6; p. 802
• Main Authors: Fujii, Kazumi, Machida, Takuji, Iizuka, Kenji, Hirafuji, Masahiko
• Format: Journal Article
• Language: English
• Published: England 01.06.2014
• Subjects: Animals; Calcium - metabolism; Calcium Channels, L-Type - physiology; Cells, Cultured; Fingolimod Hydrochloride; Lysophospholipids - pharmacology; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - metabolism; Myocytes, Smooth Muscle - metabolism; Propylene Glycols - pharmacology; Rats; Rats, Wistar; Receptors, Lysosphingolipid - physiology; Sphingosine - analogs & derivatives; Sphingosine - pharmacology; S1P3 receptor; sphingosine 1-phosphate; vascular smooth muscle cells; L-type voltage-dependent Ca2+ channel; intracellular Ca2+ concentration
• ISSN: 2042-7158
• DOI: 10.1111/jphp.12214

We investigated the effect of sphingosine 1-phosphate (S1P) on intracellular Ca(2+) dynamics in rat vascular smooth muscle cells (VSMCs). Intracellular Ca(2+) concentration ([Ca(2+) ]i) was determined using a fluorescence dye fura-2/AM. Small interfering RNAs (siRNA) were transfected into VSMCs to deplete the expression of S1P2 and S1P3 receptors. S1P induced a rapid and transient elevation in [Ca(2+) ]i, which was maximal 1 min after the stimulation, followed by a sustained increase. When extracellular Ca(2+) was removed, a decrease in resting level and a small and transient increase in [Ca(2+) ]i by S1P stimulation were observed. siRNA targeted for the S1P3 receptor almost completely inhibited the S1P-induced increase in [Ca(2+) ]i. The rapid and transient increase in [Ca(2+) ]i was significantly inhibited by diltiazem at a high concentration. Pertussis toxin and a phospholipase C (PLC) inhibitor inhibited the S1P-induced increase in [Ca(2+) ]i regardless of the presence of extracellular Ca(2+) . Furthermore, S1P activated store-operated and receptor-operated Ca(2+) entry. These results suggest that S1P increases [Ca(2+) ]i via the S1P3 receptor by inducing an influx of extracellular Ca(2+) partially through the voltage-dependent Ca(2+) channels, as well as by mobilizing Ca(2+) from its intracellular stores. S1P3 receptor-coupled Gi/o protein and PLC activation mediate the mechanisms.