Thompson M, White T, Chini E N
Signal Transduction Laboratory, Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Braz J Med Biol Res. 2006 Jun;39(6):739-48. doi: 10.1590/s0100-879x2006000600006. Epub 2006 Jun 2.
Store-operated Ca2+ entry plays an important role in Ca2+ homeostasis in cells but the mechanisms of control of these channels are not completely understood. We describe an investigation of the role of the CD38-cyclic-ADP-ribose (cADPR)-ryanodine-channel (RyR) signaling pathway in store-operated Ca2+ entry in human smooth muscle. We observed that human myometrial cells have a functional store-operated Ca2+ entry mechanism. Furthermore, we observed the presence of transient receptor potential 1, 3, 4, 5, and 6 ion channels in human myometrial cells. Store-operated Ca2+ transient was inhibited by at least 50-70% by several inhibitors of the RyR, including ryanodine (10 microM), dantrolene (10 microM), and ruthenium red (10 microM). Furthermore, the cell permeable inhibitor of the cADPR-system, 8-Br-cADPR (100 microM), is a potent inhibitor of the store-operated entry, decreasing the store operated entry by 80%. Pre-incubation of cells with 100 microM cADPR and the hydrolysis-resistant cADPR analog 3-deaza-cADPR (50 microM), but not with ADP-ribose (ADPR) leads to a 1.6-fold increase in the store-operated Ca2+ transient. In addition, we observed that nicotinamide (1-10 mM), an inhibitor of cADPR synthesis, also leads to inhibition of the store-operated Ca2+ transient by 50-80%. Finally, we observed that the transient receptor potential channels, RyR, and CD38 can be co-immunoprecipitated, indicating that they interact in vivo. Our observations clearly implicate the CD38-cADPR-ryanodine signaling pathway in the regulation of store-operated Ca2+ entry in human smooth muscle cells.
钙库操纵性钙离子内流在细胞内钙离子稳态中发挥着重要作用，但这些通道的调控机制尚未完全明确。我们描述了一项关于CD38 - 环磷酸腺苷核糖（cADPR） - 兰尼碱受体通道（RyR）信号通路在人平滑肌钙库操纵性钙离子内流中作用的研究。我们观察到，人子宫肌层细胞具有功能性的钙库操纵性钙离子内流机制。此外，我们在人子宫肌层细胞中观察到了瞬时受体电位1、3、4、5和6离子通道的存在。几种RyR抑制剂，包括兰尼碱（10微摩尔）、丹曲林（10微摩尔）和钌红（10微摩尔），可使钙库操纵性钙离子瞬变至少抑制50 - 70%。此外，cADPR系统的细胞可渗透抑制剂8 - 溴 - cADPR（100微摩尔）是钙库操纵性内流的有效抑制剂，可使钙库操纵性内流减少80%。用100微摩尔cADPR和抗水解的cADPR类似物3 - 脱氮 - cADPR（50微摩尔）预孵育细胞，但不与二磷酸腺苷核糖（ADPR）预孵育，会导致钙库操纵性钙离子瞬变增加1.6倍。此外，我们观察到，cADPR合成抑制剂烟酰胺（1 - 10毫摩尔）也会使钙库操纵性钙离子瞬变抑制50 - 80%。最后，我们观察到瞬时受体电位通道、RyR和CD38可以共免疫沉淀，表明它们在体内相互作用。我们的观察结果清楚地表明，CD38 - cADPR - 兰尼碱信号通路参与了人平滑肌细胞钙库操纵性钙离子内流的调控。
