Swegen Aleona, Grupen Christopher G, Gibb Zamira, Baker Mark A, de Ruijter-Villani Marta, Smith Nathan D, Stout Tom A E, Aitken R John
Priority Research Centre in Reproductive Science, University of Newcastle, Callaghan, NSW, Australia.
Faculty of Veterinary Science, School of Life and Environmental Sciences, University of Sydney, Camden, NSW, Australia.
Proteomics. 2017 Sep;17(17-18). doi: 10.1002/pmic.201600433.
Early pregnancy in the mare is a poorly understood, high risk period during which the embryo communicates its presence to the maternal endometrium. Remarkably, the maternal recognition of pregnancy signal is unknown in the horse. This study aimed to profile the proteins secreted by equine blastocysts into their immediate environment, along with proteins contained in the blastocoel and within the acellular embryo capsule. Embryos were recovered on day 8 after ovulation and cultured for 48 hours. Secretomes of day 9 and day 10 embryos were analyzed by LC-MS/MS and supported by analysis of blastocoel fluid and embryo capsule. Analyses revealed 72 (24 h) and 97 (48 h) unique protein IDs in the embryo secretome, 732 protein IDs in blastocoel fluid, and 11 proteins IDs in the embryo capsule. Novel findings of interest include secretion of a pregnancy specific proteinase (PAG) by the equine embryo at day 10, along with detection of a prostaglandin receptor inhibiting protein (PTGFRN) and a progesterone potentiating factor (FKBP4) in blastocoel fluid. This is the first comprehensive proteomic analysis of the equine embryo secretome, and provides new insights into the unique physiology of early pregnancy in this species.
母马的早期妊娠是一个了解甚少的高风险时期，在此期间胚胎向母体子宫内膜传达其存在。值得注意的是，马的母体妊娠识别信号尚不清楚。本研究旨在分析马囊胚分泌到其周围环境中的蛋白质，以及囊胚腔和无细胞胚胎囊内所含的蛋白质。在排卵后第8天回收胚胎并培养48小时。通过LC-MS/MS分析第9天和第10天胚胎的分泌蛋白组，并辅以囊胚腔液和胚胎囊分析。分析显示胚胎分泌蛋白组中有72个（24小时）和97个（48小时）独特的蛋白质ID，囊胚腔液中有732个蛋白质ID，胚胎囊中中有11个蛋白质ID。有趣的新发现包括马胚胎在第10天分泌一种妊娠特异性蛋白酶（PAG），以及在囊胚腔液中检测到一种前列腺素受体抑制蛋白（PTGFRN）和一种孕酮增强因子（FKBP4）。这是对马胚胎分泌蛋白组的首次全面蛋白质组学分析，并为该物种早期妊娠的独特生理学提供了新的见解。
