title: The embryotrophic activity of oviductal cell-derived complement C3b and iC3b, a novel function of complement protein in reproduction.
abstract: The oviduct-derived embryotrophic factor, ETF-3, enhances the development of trophectoderm and the hatching process of treated embryos. Monoclonal anti-ETF-3 antibody that abolishes the embryotrophic activity of ETF-3 recognized a 115-kDa protein from the conditioned medium of immortalized human oviductal cells. Mass spectrometry analysis showed that the protein was complement C3. Western blot analysis using an antibody against C3 confirmed the cross-reactivities between anti-C3 antibody with ETF-3 and anti-ETF-3 antibody with C3 and its derivatives, C3b and iC3b. Both derivatives, but not C3, were embryotrophic. iC3b was most efficient in enhancing the development of blastocysts with larger size and higher hatching rate, consistent with the previous reported embryotrophic activity of ETF-3. Embryos treated with iC3b contained iC3b immunoreactivity. The oviductal epithelium produced C3 as evidenced by the presence of C3 immunoreactivity and mRNA in the human oviduct and cultured oviductal cells. Cyclical changes in the expression of C3 immunoreactivity and mRNA were also found in the mouse oviduct with the highest expression at the estrus stage. Molecules involving in the conversion of C3b to iC3b and binding of iC3b were present in the human oviduct (factor I) and mouse preimplantation embryo (Crry and CR3), respectively. In conclusion, the present data showed that the oviduct produced C3/C3b, which was converted to iC3b to stimulate embryo development.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors.forename: Yin-Lau
authors.initials: YL
authors.lastname: Lee
authors.forename: Kai-Fai
authors.initials: KF
authors.lastname: Lee
authors.forename: Jia-Sen
authors.initials: JS
authors.lastname: Xu
authors.forename: Qing-Yu
authors.initials: QY
authors.lastname: He
authors.forename: Jen-Fu
authors.initials: JF
authors.lastname: Chiu
authors.forename: Will M
authors.initials: WM
authors.lastname: Lee
authors.forename: John M
authors.initials: JM
authors.lastname: Luk
authors.forename: William S B
authors.initials: WS
authors.lastname: Yeung
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism; D001755:Blastocyst / Q000378:metabolism; D015153:Blotting, Western; D016466:CHO Cells; D002460:Cell Line; D003179:Complement C3b / Q000737:chemistry* / Q000378:metabolism*; D006224:Cricetinae; D017077:Culture Media, Conditioned / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004622:Embryo, Mammalian / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D013058:Mass Spectrometry; D051379:Mice; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010057:Oviducts / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D011951:Receptors, Complement / Q000378:metabolism; D012098:Reproduction / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000911:Antibodies, Monoclonal; D017077:Culture Media, Conditioned; C029152:G-substrate; D009419:Nerve Tissue Proteins; D011506:Proteins; D012333:RNA, Messenger; D011951:Receptors, Complement; D003179:Complement C3b