Kawarabayashi Yasuhiro, Hai Lin, Honda Akira, Horiuchi Shinji, Tsujioka Hiroshi, Ichikawa Jun, Inoue Ryuji
Department of Physiology, Fukuoka University, Fukuoka 814-0180, Japan.
Mol Endocrinol. 2012 May;26(5):846-58. doi: 10.1210/me.2011-1259. Epub 2012 Apr 2.
Decidualization is an ovarian steroid-induced remodeling/differentiation process of uterus essential for embryo implantation and placentation. Here, we investigated the possible involvement of enhanced Ca²⁺ dynamics in the decidualization process in human endometrial stromal cells (hESC) in its connection with a recently emerging nonvoltage-gated Ca²⁺ entry channel superfamily, the transient receptor potential (TRP) protein. Combined application of 17β-estradiol (E₂) (10 nM) and progesterone (P₄) (1 μM) for 7-14 d resulted in morphological changes of hESC characteristic of decidualization (i.e. cell size increase), whereas sole application of E₂ exerted little effects. A 7- to 14-d E₂/P₄ treatment greatly increased the expression level of decidualization markers IGF binding protein-1 (IGFBP-1) and prolactin and also up-regulated the expression of TRPC1, a canonical TRP subfamily member that has been implicated in store-operated Ca²⁺ influx (SOC) in other cell types. In parallel with this up-regulation, SOC activity in hESC, the nuclear translocation of phosphorylated cAMP responsive element binding protein (p-CREB) and the expression of Forkhead box protein 01 were enhanced significantly. Small interfering RNA knockdown of TRPC1 counteracted the E₂/P₄-induced up-regulation of IGFBP-1 and prolactin and enhancement of SOC activity together with the inhibition of hESC size increase, p-CREB nuclear translocation, and FOXO1 up-regulation. Coadministration of SOC inhibitors SK&F96365 or Gd³⁺ with E₂/P₄ also suppressed the up-regulation of IGFBP-1 and hESC size increase. Similar inhibitory effects were observed with extracellularly applied TRPC1 extracellular loop 3-directed antibody, which is known to bind a near-pore domain of TRPC1 channel and block its Ca²⁺ transporting activity. These results strongly suggest that up-regulation of TRPC1 protein and consequent enhancement of SOC-mediated Ca²⁺ influx may serve as a crucial step for the decidualization process of hESC probably via p-CREB-dependent transcriptional activity associated with FOXO1 activation.
蜕膜化是一种由卵巢甾体激素诱导的子宫重塑/分化过程，对胚胎着床和胎盘形成至关重要。在此，我们研究了增强的Ca²⁺动力学在人子宫内膜基质细胞（hESC）蜕膜化过程中的可能作用，及其与最近新出现的非电压门控Ca²⁺内流通道超家族——瞬时受体电位（TRP）蛋白的联系。联合应用17β-雌二醇（E₂）（10 nM）和孕酮（P₄）（1 μM）7至14天导致hESC出现蜕膜化特征性的形态变化（即细胞大小增加），而单独应用E₂几乎没有作用。7至14天的E₂/P₄处理显著提高了蜕膜化标志物胰岛素样生长因子结合蛋白-1（IGFBP-1）和催乳素的表达水平，同时也上调了TRPC1的表达，TRPC1是TRP家族的一个典型成员，在其他细胞类型中与储存性Ca²⁺内流（SOC）有关。与此上调同时，hESC中的SOC活性、磷酸化cAMP反应元件结合蛋白（p-CREB）的核转位以及叉头框蛋白01的表达均显著增强。TRPC1的小干扰RNA敲低抵消了E₂/P₄诱导的IGFBP-1和催乳素上调以及SOC活性增强，同时抑制了hESC大小增加、p-CREB核转位和FOXO1上调。SOC抑制剂SK&F96365或Gd³⁺与E₂/P₄共同给药也抑制了IGFBP-1上调和hESC大小增加。用细胞外应用的TRPC1细胞外环3定向抗体也观察到类似的抑制作用，已知该抗体可结合TRPC1通道的近孔结构域并阻断其Ca²⁺转运活性。这些结果强烈表明，TRPC1蛋白的上调以及随之而来的SOC介导的Ca²⁺内流增强可能是hESC蜕膜化过程的关键步骤，可能是通过与FOXO1激活相关的p-CREB依赖性转录活性实现的。
