Lachance Catherine, Bailey Janice L, Leclerc Pierre
Département d'Obstétrique et de Gynécologie, Centre de Recherche en Biologie de la Reproduction, Université Laval, Unité de Recherche en Ontogénie et Reproduction, Centre de recherche du CHUQ (CHUL), T1-49, 2705 boul. Laurier, Québec, QC, Canada G1V 4G2.
Hum Reprod. 2007 Oct;22(10):2606-14. doi: 10.1093/humrep/dem242. Epub 2007 Aug 1.
Within the female genital tract, spermatozoa undergo a series of membranous and intracellular transformations to become competent at fertilizing the oocyte. In the bovine, previous studies have shown that two oviductal proteins, heat shock protein 60 (Hsp60) and glucose regulated protein 78 (Grp78), bind to spermatozoa and may be involved in this acquisition of fertilizing competence.
Immunohistochemical studies were performed on human endometrial and oviduct tissues to localize these two chaperones in the female genital tract. Human spermatozoa were incubated under capacitating conditions in the presence or absence of recombinant Hsp60 or Grp78. Following a 4-h incubation, the effects of these proteins were evaluated on sperm acrosomal integrity, motility, protein phosphotyrosine content and free intracellular calcium concentrations.
Both chaperones were present in the uterus and oviduct epithelial cells and were shown to bind to human spermatozoa. Incubation with either exogenous Hsp60 or Grp78 did not affect sperm viability, motility or acrosomal integrity. Hsp60 partially prevented the increase in p81 phosphotyrosine content induced by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine and both chaperones significantly increased the sperm intracellular calcium concentration. Moreover, the progesterone-induced increase in intracellular calcium was higher when sperm were pre-treated with either Hsp60 or Grp78.
Our study suggests that these two proteins may affect human sperm intracellular signalling pathways and capacitation.
在女性生殖道内，精子会经历一系列膜性和细胞内的转变，从而具备使卵母细胞受精的能力。在牛身上，先前的研究表明，两种输卵管蛋白，即热休克蛋白60（Hsp60）和葡萄糖调节蛋白78（Grp78），会与精子结合，并可能参与受精能力的获得过程。
对人子宫内膜和输卵管组织进行免疫组织化学研究，以确定这两种伴侣蛋白在女性生殖道中的定位。在有或没有重组Hsp60或Grp78存在的情况下，将人精子在获能条件下孵育。孵育4小时后，评估这些蛋白质对精子顶体完整性、活力、蛋白磷酸酪氨酸含量和细胞内游离钙浓度的影响。
这两种伴侣蛋白均存在于子宫和输卵管上皮细胞中，并显示能与人精子结合。用外源性Hsp60或Grp78孵育均不影响精子活力、运动能力或顶体完整性。Hsp60部分阻止了磷酸二酯酶抑制剂3-异丁基-1-甲基黄嘌呤诱导的p81磷酸酪氨酸含量增加，且两种伴侣蛋白均显著提高了精子细胞内钙浓度。此外，当精子用Hsp60或Grp78预处理时，孕酮诱导的细胞内钙增加更高。
我们的研究表明，这两种蛋白质可能影响人类精子的细胞内信号通路和获能过程。
