Is the zona pellucida an intrinsic source of signals activating maternal recognition of the developing mammalian embryo?
Is the zona pellucida an intrinsic source of signals activating maternal recognition of the developing mammalian embryo?
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DOI：
10.1016/j.jri.2009.04.001
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发表时间：
2009-07-01
影响因子：
3.4
通讯作者：
Toshimori, Kiyotaka
中科院分区：
文献类型：
--
作者：
Fujiwara, Hiroshi;Araki, Yoshihiko;Toshimori, Kiyotaka
接受胚胎植入的哺乳动物母亲必须以物种受限的方式识别发育中的胚胎。我们先前观察到，来自早孕小鼠的免疫细胞可以促进胚泡移植假孕小鼠的子宫内膜分化和胚胎着床。尽管确切的机制尚不清楚，但有人认为，在怀孕早期识别出发育中的胚胎后，母体免疫系统经历了功能变化。由于当发育中的胚胎被透明带(ZP)包围时，免疫细胞不可能直接与其相互作用，因此推测胚胎在孵化前在输卵管中产生特定的胚胎和物种特异性的可溶性因子(S)。作为这一因子的候选者，我们已经注意到ZP在卵泡发生过程中通常被保护而不受免疫攻击。已知ZP特异性糖蛋白在精子的物种和卵母细胞特异性结合中发挥重要作用，ZP也可以被认为是丰富的卵母细胞和物种特异性糖蛋白的储存。与未受精的卵母细胞相比，发育中的胚胎可能会在受精后立即开始降解ZP，并使用皮质颗粒释放的酶或发育中的胚胎产生的酶一直持续到孵化。因此，发育中的胚胎可能会在非常早期的阶段就向免疫系统提供包括寡糖链在内的ZP降解产物。综上所述，我们在这里提出了一个新的假设，即这些ZP-衍生物可以作为发育中的胚胎的内在信号，由免疫系统识别母体。(C)2009爱思唯尔爱尔兰有限公司。保留所有权利。
Mammalian mothers undergoing embryo implantation must specifically recognize the developing embryo in a species-restricted manner. We previously observed that immune cells derived from early pregnant mice could promote endometrial differentiation and embryo implantation in blastocyst-transferred pseudopregnant mice. Although the precise mechanism remains unknown, it is suggested that the maternal immune system undergoes functional changes after recognizing developing embryos from the very early stages of pregnancy. Since it is physically impossible for immune cells to directly interact with the developing embryo while it is surrounded by the zona pellucida (ZP), it is speculated that the embryo produces certain embryo- and species-specific soluble factor(s) in the oviduct before hatching. As a candidate for this factor, we have paid attention to the ZP that is normally protected from immunological attack during oogenesis in the ovarian follicle. ZP-specific glycoproteins are known to play important roles in the species- and oocyte-specific binding of sperm, and the ZP can also be considered an abundant store of oocyte- and species-specific glycoproteins. In contrast to unfertilized oocytes, developing embryos may degrade the ZP starting just after fertilization and proceeding until hatching using enzymes that are released from cortical granules or produced by the developing embryo. Accordingly, the developing embryo might provide ZP-degradation products including oligosaccharide chains to the immune system from the very early stages. Taken together, we propose here a novel hypothesis that these ZP-derivatives can act as an intrinsic signal from the developing embryo for maternal recognition by the immune system. (C) 2009 Elsevier Ireland Ltd. All rights reserved.