| Co-Investigator(Kenkyū-buntansha) |
OHSAKI Takashi Kansai Med. Univ., Obsterics and Gynecology, Assistant Professor, 医学部, 講師 (70257913)
YASUDA Katsuhiko Kansai Med. Univ., Obsterics and Gynecology, Associate Professor, 医学部, 助教授 (90174507)
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| Research Abstract |
For successful implantation in humans, precisely timed changes in the endometrium including the decidual transformation of stromal cells are believed to be very important. Although decidualization is primarily under the control of progesterone secreted by corpus luteum, recent studies have demonstrated that various other factors act as local mediators in the regulation of decidualization. And there should exist some second messenger molecules in progesterone action on endometrial stromal cells. In this study, we have developed an in vitro model of human decidualizaiton. Human endometrial stromal cells cultured in the presence of progesterone undergo morphological differentiation and produce decidual proteins such as PRL. With this model of in vitro decidualization, we tried to identify the genes involved in decidualization. Human endometrial stromal cells from proliferative endometrial tissues were isolated and cDNA libraries were made from poly (A)+RNAs. cDNA subtraction, expression a
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rray, and differential display methods were used to identify genes involved in endometrial stromal cell differentiation induced by progesterone. As a results, several genes including tissue transglutaminase (Tgase), TIMP-3, CD63, IL-15, and unreported gene of UK10 were identified. Tissue Tgase gene was induce after 6 hours culture with progesterone and the unreported gene, UK10, was induced within 1 hour culture, CD63 was down regulated and IL-15 was unregulated by progesterone after 7-10 days culture with progesterone. The enzyme tissue Tgase is a member of the Tgase family that catalyzes calcium-dependent acyl transfer reaction between g-carboxamide group of the glutamine residues in peptides and either primary amines or e-amino groups of the lysine residues in peptides. Tissue Tgase is reported in various organs and tissues. The biological function of tissue Tgase is not completely understood, but it is suggested that the enzyme has roles in regulation of cell growth and differentiation, in calcium-dependent cross linking of cell membrane, in the programmed cell death, and in the activation and dimerization of cytokines. The important role of tissue Tgase in decidualization was suggested, since the addition of a specific substrate competitor, or the antisense oligodeoxynucleotide to tissue Tgase gene inhibited progesterone-induced decidualizaiton. Although the substrate(s) of tissue Tgase in endometrium for is unknown, the molecule(s) should be indispensable for stromal cell differentiation induced by progesterone. As to UK10 gene, we found the gene was expressed in mid-secretary phase endometrium, and its expression was decreased in patients of implantation failure. IL-15 mRNA levels as well as IL-15 production by endometrial stromal cells was apparently increased by progesterone. And it was suggested that IL-15 production stimulates the induction of uterine NK cells and is a key event for the successful pregnancy establishment. In addition, we have clarified a gene for progesterone regulation, 20a-hydroxysteroid dehydrogenase for the first time. Less
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