Cumulus cells accelerate oocyte aging by releasing soluble Fas ligand in mice.
Although previous studies have suggested that cumulus cells (CCs) accelerate oocyte aging by secreting soluble and heat-sensitive paracrine factors, the factors involved are not well characterized. Because Fas-mediated apoptosis represents a major pathway in induction of apoptosis in various cells, we proposed that CCs facilitate oocyte aging by releasing soluble Fas ligand (sFasL). In this study, we reported that when the aging of freshly ovulated mouse oocytes were studied in vitro, both the apoptotic rates of CCs and the amount of CCs produced sFasL increased significantly with the culture time. We found that oocytes expressed stable levels of Fas receptors up to 24 h of in vitro aging. Moreover, culture of cumulus-denuded oocytes in CCs-conditioned CZB medium (CM), in CZB supplemented with recombinant sFasL, or in CM containing sFasL neutralizing antibodies all showed that sFasL impaired the developmental potential of the oocytes whereas facilitating activation and fragmentation of aging oocytes. Furthermore, CCs from the FasL-defective gld mice did not accelerate oocyte aging due to the lack of functional FasL. In conclusion, we propose that CCs surrounding aging oocytes released sFasL in an apoptosis-related manner, and the released sFasL accelerated oocyte aging by binding to Fas receptors.
College of Life Science, Northeast Agricultural University, Harbin, 150030, P. R. China.
Jiang
J
Zhu
College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City 271018, P. R. China.
Jie
J
Zhang
College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City 271018, P. R. China.
Hong
H
Li
College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City 271018, P. R. China.
Tian-Yang
TY
Wang
College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City 271018, P. R. China.
Chuan-Xin
CX
Zhang
College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City 271018, P. R. China.
Ming-Jiu
MJ
Luo
1] College of Life Science, Northeast Agricultural University, Harbin, 150030, P. R. China [2] College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City 271018, P. R. China.
Jing-He
JH
Tan
D000818:Animals; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002450:Cell Communication; D002478:Cells, Cultured; D016922:Cellular Senescence; D017077:Culture Media, Conditioned / Q000494:pharmacology; D054885:Cumulus Cells / Q000187:drug effects / Q000378:metabolism*; D053222:Fas Ligand Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction
D057134:Antibodies, Neutralizing; D017077:Culture Media, Conditioned; D053222:Fas Ligand Protein; D006861:Hydrogen Peroxide