title: Cumulus Cells Block Oocyte Meiotic Resumption via Gap Junctions in Cumulus Oocyte Complexes Subjected to DNA Double-Strand Breaks.
abstract: During mammalian oocyte growth, genomic DNA may accumulate DNA double-strand breaks (DSBs) induced by factors such as reactive oxygen species. Recent evidence demonstrated that slight DSBs do not activate DNA damage checkpoint proteins in denuded oocytes. These oocytes, even with DNA DSBs, can resume meiosis and progress to metaphase of meiosis II. Meiotic resumption in oocytes is also controlled by the surrounding cumulus cells; accordingly, we analyzed whether cumulus-cell enclosed oocytes (CEOs) with DNA damage are able to resume meiosis. Compared with DNA-damaged denuded oocytes, we found that meiotic resumption rates of CEOs significantly decreased. To assess the mechanism by which cumulus cells block meiotic resumption in CEOs with DNA DSBs, we treated the cumulus oocyte complex with the gap junction inhibitor carbenoxolone and found that carbenoxolone can rescue the block in CEO meiosis induced by DNA DSBs. Since cumulus cell-synthesized cAMPs can pass through the gap junctions between oocyte and cumulus cell to block oocyte meiosis, we measured the expression levels of adenylate cyclase 1 (Adcy1) in cumulus cells, and G-protein coupled receptor 3 (Gpr3) and phosphodiesterase 3A (Pde3a) in oocytes, and found that the mRNA expression level of Adcy1 increased significantly in DNA-damaged cumulus cells. In conclusion, our results indicate that DNA DSBs promote cAMP synthesis in cumulus cells, and cumulus cAMPs can inhibit meiotic resumption of CEOs through gap junctions.
authors.affiliation: College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.|Institute of Reproductive Science, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Sun
authors.affiliation: College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.affiliation: College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.
authors.forename: Feng-Yun
authors.initials: FY
authors.lastname: Xie
authors.affiliation: College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.|Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, Qingdao Agricultural University, Qingdao, Shandong, China.|Institute of Reproductive Science, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.affiliation: College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.|Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, Qingdao Agricultural University, Qingdao, Shandong, China.|Institute of Reproductive Science, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.
authors.forename: Shen
authors.initials: S
authors.lastname: Yin
authors.affiliation: College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.|Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, Qingdao Agricultural University, Qingdao, Shandong, China.|Institute of Reproductive Science, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong, China.
authors.forename: Jun-Yu
authors.initials: JY
authors.lastname: Ma
mesh_terms: D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002229:Carbenoxolone / Q000494:pharmacology; D054885:Cumulus Cells / Q000166:cytology / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3 / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D005260:Female; D017629:Gap Junctions / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D008540:Meiosis / Q000187:drug effects; D008677:Metaphase; D008813:Mice, Inbred ICR; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism
chemical_list: D000262:Adenylyl Cyclases; D002229:Carbenoxolone; D000242:Cyclic AMP; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D004247:DNA; D006657:Histones; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C494613:GPR3 protein, mouse; C517289:Pde3a protein, mouse; C106670:adenylyl cyclase 1; C475961:gamma-H2AX protein, mouse