Tribe Rachel M, Moriarty Patrick, Dalrymple Annette, Hassoni Abdul A, Poston Lucilla
Parturition Research, Maternal and Fetal Research Unit, Department of Women's Health, King's College London, St. Thomas' Hospital Campus, United Kingdom.
Biol Reprod. 2003 May;68(5):1842-9. doi: 10.1095/biolreprod.102.011403. Epub 2002 Dec 11.
We have previously reported increased protein expression of sarcoplasmic reticulum calcium ATPase (SERCA) 2b in myometrium from women in labor at term, but the stimulus for this change is unknown. Proinflammatory cytokines have been implicated in the cascade of events leading to preterm and term labor, and we hypothesize that interleukin (IL)-1beta may induce changes in key calcium homeostatic mechanisms and, in turn, augment myometrial contractility before labor. The aim of the present study was to investigate the long-term effects of IL-1beta on SERCA 2b protein expression, calcium mobilization from intracellular stores, and store-operated calcium entry. Myometrial biopsies were obtained, with consent, from women undergoing elective cesarean section at term. Primary-cultured human myometrial smooth muscle (HMSM) cells were exposed to IL-1beta (10 ng/ml) for 24 h or to culture medium alone (control). Cells were subsequently used in Western blot studies or loaded with fura-2 to assess calcium dynamics using fluorescent digital imaging. The present study clearly demonstrated that IL-1beta significantly increased SERCA 2b protein expression in HMSM cells. Cyclopiazonic acid-induced calcium transients were also augmented, predominantly by activation of lanthanum-sensitive, store-operated calcium entry. HMSM cell excitability was enhanced, as evidenced by increased basal calcium entry and the initiation of spontaneous calcium transients in 37% of IL-1beta-treated cells. IL-1beta modulation of calcium mobilization may be an important mechanism in the cascade of events preparing the pregnant uterus for labor.
我们之前报道过，足月分娩女性子宫肌层中肌浆网钙ATP酶（SERCA）2b的蛋白表达增加，但这种变化的刺激因素尚不清楚。促炎细胞因子参与了导致早产和足月分娩的一系列事件，我们推测白细胞介素（IL）-1β可能诱导关键钙稳态机制的变化，进而在分娩前增强子宫肌层的收缩力。本研究的目的是探讨IL-1β对SERCA 2b蛋白表达、细胞内钙库钙动员以及钙库操纵性钙内流的长期影响。经同意，从足月行择期剖宫产的女性获取子宫肌层活检组织。将原代培养的人子宫肌层平滑肌（HMSM）细胞暴露于IL-1β（10 ng/ml）24小时或仅暴露于培养基（对照）。随后将细胞用于蛋白质印迹研究，或加载fura-2以使用荧光数字成像评估钙动力学。本研究清楚地表明，IL-1β显著增加了HMSM细胞中SERCA 2b的蛋白表达。环匹阿尼酸诱导的钙瞬变也增强，主要是通过激活镧敏感的钙库操纵性钙内流。HMSM细胞兴奋性增强，37%接受IL-1β处理的细胞基础钙内流增加和自发钙瞬变的启动证明了这一点。IL-1β对钙动员的调节可能是使妊娠子宫为分娩做好准备的一系列事件中的一个重要机制。
