Department of Physiology, Second Military Medical University, and Department of Obsetrics and Gynecology, Changhai Hospital, 800 Xiangyin Road, Shanghai 200433, PR China.
J Clin Endocrinol Metab. 2012 Oct;97(10):E1851-61. doi: 10.1210/jc.2011-3383. Epub 2012 Aug 6.
Our previous study has demonstrated that CRH has differential effects on human uterine contractility before and after onset of labor. Intracellular Ca2+ concentration ([Ca2+]i) mobilization plays an important role in the control of uterine contraction.
Our objective was to investigate the effects of CRH on [Ca2+]i homeostasis in laboring and nonlaboring myometrial cells and determine subsequent signaling involved in [Ca2+]i regulation by CRH.
The myometrial tissues were obtained from pregnant women who were undergoing or not undergoing labor at term. [Ca2+]i was determined by Ca2+ imaging system using the fluorescent dye fura-2-acetoxymethyl ester. Western blot analysis, ELISA, and RIA were used to determine the signaling pathways induced by CRH.
CRH induced Ca2+ transient in laboring cells, which was blocked by CRH receptor type 1 (CRHR1) antagonist antalarmin. CRHR1 knockdown impaired this effect of CRH. CRH activated Gi protein, decreased cAMP production, and induced phosphorylated phospholipase C-β3 and inositol-1,4,5-triphosphate production. Phospholipase C and inositol-1,4,5-triphosphate receptor inhibitors blocked the CRH-induced Ca2+ transient in laboring cells. CRH did not induce whereas antalarmin induced the Ca2+ transient in nonlaboring cells. Knockdown of CRHR1 impaired the effect of antalarmin. CRH acted on CRHR1 to activate Gs in nonlaboring cells. Forskolin blocked antalarmin-induced Ca2+ transient.
CRH acts on CRHR1 to activate different signaling pathways before and after onset of labor, thereby resulting in differential calcium signaling in response to CRH. The signaling pathways of CRHR1 might serve as a target for the development of new therapeutic strategies for preterm birth.
我们之前的研究表明，CRH 在分娩前后对人子宫收缩力有不同的影响。细胞内钙离子浓度（[Ca2+]i）动员在子宫收缩的控制中起重要作用。
我们的目的是研究 CRH 对分娩中和未分娩的子宫平滑肌细胞[Ca2+]i 稳态的影响，并确定 CRH 调节[Ca2+]i 所涉及的后续信号。
从正在分娩和未分娩的足月孕妇中获取子宫组织。使用荧光染料 fura-2-乙酰氧基甲酯通过 Ca2+ 成像系统测定 [Ca2+]i。使用 Western blot 分析、ELISA 和 RIA 来确定 CRH 诱导的信号通路。
CRH 在分娩细胞中诱导 Ca2+ 瞬变，该效应被 CRH 受体 1（CRHR1）拮抗剂 antalarmin 阻断。CRHR1 敲低削弱了 CRH 的这种作用。CRH 激活 Gi 蛋白，减少 cAMP 产生，并诱导磷酸化磷脂酶 C-β3 和肌醇 1,4,5-三磷酸的产生。磷脂酶 C 和肌醇 1,4,5-三磷酸受体抑制剂阻断了分娩细胞中 CRH 诱导的 Ca2+ 瞬变。CRH 不诱导而 antalarmin 诱导未分娩细胞的 Ca2+ 瞬变。CRHR1 的敲低削弱了 antalarmin 的作用。CRH 在未分娩细胞中作用于 CRHR1 以激活 Gs。forskolin 阻断了 antalarmin 诱导的 Ca2+ 瞬变。
CRH 在分娩前后作用于 CRHR1 以激活不同的信号通路，从而导致对 CRH 的不同钙信号反应。CRHR1 的信号通路可能作为开发治疗早产的新治疗策略的靶点。
