title: Estrogen stimuli promote osteoblastic differentiation via the subtilisin-like proprotein convertase PACE4 in MC3T3-E1 cells.
abstract: Estrogenic compounds include endogenous estrogens such as estradiol as well as soybean isoflavones, such as daidzein and its metabolite equol, which are known phytoestrogens that prevent osteoporosis in postmenopausal women. Indeed, mineralization of MC3T3-E1 cells, a murine osteoblastic cell line, was significantly decreased in medium containing fetal bovine serum treated with charcoal-dextran to deplete endogenous estrogens, but estradiol and these soybean isoflavones dose-dependently restored the differentiation of MC3T3-E1 cells; equol was tenfold more effective than daidzein. These differentiation-promoting effects were inhibited by the addition of fulvestrant, which is a selective downregulator of estrogen receptors. Analysis of the expression pattern of bone-related genes by reverse transcription PCR (RT-PCR)/quantitative real-time PCR (qRT-PCR), which focused on responsiveness to the estrogen stimuli, revealed that the transcription of PACE4, a subtilisin-like proprotein convertase, was tightly linked with the differentiation of MC3T3-E1 cells induced by estrogen stimuli. Moreover, treatment with RNAi of PACE4 in MC3T3-E1 cells resulted in a drastic decrease of mineralization in the presence of estrogen stimuli. These results strongly suggest that PACE4 participates in bone formation at least in osteoblast differentiation, and estrogen receptor-mediated stimuli induce osteoblast differentiation through the upregulation of PACE4 expression.
authors.affiliation: Department of Biological Science and Technology, Institute of Technology and Science, The University of Tokushima Graduate School, #2-1, Minami-josanjima, Tokushima, 770-8506, Japan.
authors.forename: Hyejin
authors.initials: H
authors.lastname: Kim
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tabata
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Tomoyasu
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ueno
authors.forename: Shigeto
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Keizo
authors.initials: K
authors.lastname: Yuasa
authors.forename: Akihiko
authors.initials: A
authors.lastname: Tsuji
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nagamune
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D002454:Cell Differentiation; D002606:Charcoal / Q000737:chemistry; D019902:Chondrocytes / Q000166:cytology; D003470:Culture Media / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry; D004958:Estradiol / Q000031:analogs & derivatives / Q000737:chemistry; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D000077267:Fulvestrant; D007529:Isoflavones / Q000737:chemistry; D051379:Mice; D010006:Osteoblasts / Q000166:cytology*; D043484:Proprotein Convertases / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013025:Glycine max; D020860:Subtilisin / Q000737:chemistry*; D014158:Transcription, Genetic
chemical_list: D003470:Culture Media; D003911:Dextrans; D004967:Estrogens; D007529:Isoflavones; D002606:Charcoal; D000077267:Fulvestrant; D004958:Estradiol; C513086:Pcsk6 protein, mouse; D043484:Proprotein Convertases; D020860:Subtilisin