title: Critical role of TRPC1-mediated Ca²⁺ entry in decidualization of human endometrial stromal cells.
abstract: 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.
authors.affiliation: Department of Physiology, Fukuoka University, Fukuoka 814-0180, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kawarabayashi
authors.forename: Lin
authors.initials: L
authors.lastname: Hai
authors.forename: Akira
authors.initials: A
authors.lastname: Honda
authors.forename: Shinji
authors.initials: S
authors.lastname: Horiuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsujioka
authors.forename: Jun
authors.initials: J
authors.lastname: Ichikawa
authors.forename: Ryuji
authors.initials: R
authors.lastname: Inoue
mesh_terms: D000328:Adult; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D003656:Decidua / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004717:Endometrium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D010766:Phosphorylation / Q000187:drug effects; D011388:Prolactin / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: C115163:CREB1 protein, human; D002121:Calcium Channel Blockers; D017362:Cyclic AMP Response Element-Binding Protein; C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; C032231:IGFBP1 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D011388:Prolactin