Abstract：
Cyclic ADP-ribose (cADPR) has emerged as a calcium-regulating second messenger in smooth muscle cells. CD38 protein possesses ADP-ribosyl cyclase and cADPR hydrolase activities and mediates cADPR synthesis and degradation. We have previously shown that CD38 expression is regulated by estrogen and progesterone in the myometrium. Considering hormonal regulation in gestation, the objective of the present study was to determine the role of CD38/cADPR signaling in the regulation of intracellular calcium upon contractile agonist stimulation using immortalized pregnant human myometrial (PHM1) cells. Western blot, immunofluorescence, and biochemical studies confirmed CD38 expression and the presence of ADP-ribosyl cyclase (2.6 ± 0.1 pmol/mg) and cADPR hydrolase (26.8 ± 6.8 nmoles/mg/h) activities on the PHM1 cell membrane. Oxytocin, PGF2α, and ET-1 elicited [Ca2+]i responses, and 8-Br-cADPR, a cADPR antagonist significantly attenuated agonist-induced [Ca2+]i responses between 20% and 46% in average. The findings suggest that uterine contractile agonists mediate their effects in part through CD38/cADPR signaling to increase [Ca2+]i and presumably uterine contraction. As studies in humans are limited by the availability of myometrium from healthy donors, PHM1 cells form an in vitro model to study human myometrium.
摘要：
环状ADP-核糖（cADPR）已成为平滑肌细胞中的钙调节第二信使。CD38蛋白具有ADP-核糖基环化酶和cADPR水解酶活性，并介导cADPR的合成和降解。我们先前已经表明，子宫肌层中CD38的表达受雌激素和孕激素的调节。考虑到妊娠期的荷尔蒙调节，本研究的目的是确定CD38/cADPR信号传导在使用永生化妊娠人类子宫肌层(PHM1)细胞刺激收缩激动剂后调节细胞内钙中的作用.蛋白质印迹,免疫荧光，生化研究证实了CD38的表达以及PHM1细胞膜上ADP-核糖基环化酶（2.6±0.1pmol/mg）和cADPR水解酶（26.8±6.8nmoles/mg/h）活性的存在。催产素,PGF2α,ET-1引起[Ca2+]i响应，和8-Br-cADPR，cADPR拮抗剂可显著减弱激动剂诱导的[Ca2+]i反应，平均在20%至46%之间。研究结果表明，子宫收缩激动剂部分通过CD38/cADPR信号传导来介导其作用，以增加[Ca2]i和可能的子宫收缩。由于人体研究受到健康供体子宫肌层的限制，PHM1细胞形成体外模型以研究人子宫肌层。
