Plasminogen Improves Mouse IVF by Interactions with Inner Acrosomal Membrane-Bound MMP2 and SAMP14
Plasminogen Improves Mouse IVF by Interactions with Inner Acrosomal Membrane-Bound MMP2 and SAMP14
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DOI：
10.1095/biolreprod.115.133496
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发表时间：
2016-04-01
影响因子：
3.6
通讯作者：
Oko, Richard
中科院分区：
文献类型：
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作者：
Ferrer, Marvin J. S.;Xu, Wei;Oko, Richard
精子必须穿透卵母细胞、卵丘和透明带(ZP)的外包膜，才能受精。这可能需要精子顶体内膜(IAM)上的酶，其中之一是基质金属蛋白酶(MMP2)，暴露在输卵管液中的因子中。纤溶酶原存在于输卵管液中，激活体细胞组织中的MMP2。本研究的目的是：1)研究纤溶酶原与IAM结合的纤溶酶原激活物受体(SAMP14)和-MMP2之间可能的相互作用；2)证明纤溶酶原存在于受精部位的细胞外环境中；3)提供纤溶酶原在受精过程中起作用的证据。用纤溶酶和/或纤溶酶原(纤溶酶/原)处理的牛和大鼠精子超声提取液的酶谱显示，低至1微克/毫升的浓度可加速MMP2活性的启动。免疫组织化学和免疫荧光分析表明，纤溶酶/原存在于小鼠卵巢和输卵管卵母细胞、输卵管上皮、卵丘周围和卵丘细胞的胞浆中。我们修改了标准的体外受精(IVF)方法，通过将受精过程中的精子密度降低约100倍，并对卵丘完整和裸露的卵母细胞进行比较，使其更接近自然受精。在小鼠的体外受精液中加入纤溶酶原显著促进受精，而MMP2抗体在这些条件下显著抑制精子穿透。SAMP14抗体可阻断纤溶酶原对体外受精的改善作用。此外，MMP2抗体的抑制与精子分散卵丘的失败是一致的。我们提供了纤溶酶原本身和通过MMP2相关机制提高卵母细胞受精能力的证据，并证明了其在卵母细胞包被精子穿透中的作用。
Spermatozoa must penetrate the outer investments of the oocyte, the cumulus oophorus and the zona pellucida (ZP), in order for fertilization to occur. This may require exposure of enzymes on the sperm's inner acrosomal membrane (IAM), one of which is matrix metalloproteinase (MMP) 2, to factors in oviductal fluid. Plasminogen is present in oviductal fluid and activates MMP2 in somatic tissues. The objectives of this study were: 1) to examine possible interactions between plasminogen and IAM-bound plasminogen activator receptor (SAMP14) and -MMP2, 2) to demonstrate plasminogen's presence in the extracellular environment at the site of fertilization, and 3) to provide evidence that plasminogen plays a role in fertilization. Zymographs of sonicated bull and rat sperm extracts incubated with plasmin and/or plasminogen (plasmin/ogen) showed acceleration of initiation of MMP2 activity in concentrations as low as 1 mu g/ml. Immunohistochemical and immunofluorescence analysis of plasmin/ogen revealed its presence in the cytoplasm of mouse ovarian and oviductal oocytes, oviductal epithelium, around the ZP, and amongst the cumulus cells. We modified the standard in vitro fertilization (IVF) approach to more closely mimic natural fertilization by reducing sperm concentration during insemination by similar to 100x and also comparing cumulus-intact and denuded oocytes. In mice, addition of plasminogen in IVF medium significantly improved fertilization, while MMP2 antibody significantly inhibited sperm penetration in these conditions. IVF improvement by plasminogen was blocked by SAMP14 antibody. Furthermore, MMP2 antibody inhibition was coincident with a failure by spermatozoa to disperse the cumulus oophorus. We provide evidence that plasminogen on its own and through an MMP2-related mechanism improves the ability of oocytes to be fertilized, and demonstrate its effect in sperm penetration of oocyte investments.