"Sperm maturation and capacitation: Roles of Chaperone Proteins, Clusterin and Hsp70"

“精子成熟和获能：伴侣蛋白、簇蛋白和 Hsp70 的作用”

• 批准号: 183958-2012
• 负责人: Tanphaichitr, Nongnuj
• 金额: $ 1.97万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=506420
• 关键词: Sperm; maturation; capacitation; Roles; Chaperone

Raising efficiency in fertilization would lead to increased success in agricultural animal production. Sperm are produced in the testis, but testicular sperm cannot fertilize an egg. They have to undergo biochemical modifications during their transit through the epididymis (called sperm maturation) and their migration inside the female reproductive tract (called capacitation). A number of egg extracellular matrix, zona pellucida (ZP), binding proteins secreted by epididymal epithelial cells deposit onto the transit sperm surface. Some of these proteins tend to aggregate and within a small epididymal volume, they may precipitate without rescuing mechanisms. Clusterin (CLU), also secreted by epididymal epithelial cells, has a chaperone property and propensity to bind to other proteins at their hydrophobic (non-polar, water repellant) domains. We propose that CLU prevents ZP binding proteins from precipitation and chaperones them to the sperm surface. Biochemical experiments will be performed to validate that CLU can prevent precipitation/aggregation of ZP binding proteins (e.g., arylsulfatase A, SED1), and CLU's chaperone activity will be assessed by comparing the presence of ZP binding proteins on sperm in Clu genetically null mice versus that in wild type mice. During capacitation, our recent results suggest that ZP binding proteins conglomerate as complexes, and another chaperone Hsp70 protein may play roles in this conglomeration. We will identify ZP binding proteins in the complex by mass spectrometry and validate the role of Hsp70 by assessing whether sperm have more fertilizing ability (capacitated) after treating non-capacitated sperm with Hsp70. Results from our proposed work can be translated to enhance fertilizing ability of sperm that have low levels of certain ZP binding proteins. They will be treated with CLU + the desired ZP binding proteins, as well as Hsp70 to enhance the complex formation. Our study will also give a better understanding of sperm maturation and capacitation processes.

提高施肥效率将提高农业动物生产的成功率。 精子在睾丸中产生，但睾丸精子不能使卵子受精。 它们在通过附睾（称为精子成熟）和在女性生殖道内迁移（称为获能）期间必须经历生化修饰。 许多卵细胞外基质、透明带（ZP）、附睾上皮细胞分泌的结合蛋白沉积在转运精子表面。 其中一些蛋白质倾向于聚集，并且在较小的附睾体积内，它们可能会在没有救援机制的情况下沉淀。 簇蛋白 (CLU) 也由附睾上皮细胞分泌，具有伴侣特性并倾向于在其疏水（非极性、防水）结构域与其他蛋白质结合。 我们认为 CLU 可以防止 ZP 结合蛋白沉淀并陪伴它们到达精子表面。 将进行生化实验以验证 CLU 可以防止 ZP 结合蛋白（例如芳基硫酸酯酶 A、SED1）沉淀/聚集，并且将通过比较 Clu 基因缺失小鼠与野生型小鼠精子上 ZP 结合蛋白的存在情况来评估 CLU 的伴侣活性。 在获能过程中，我们最近的结果表明 ZP 结合蛋白聚集成复合物，而另一种伴侣 Hsp70 蛋白可能在该聚集体中发挥作用。 我们将通过质谱法鉴定复合物中的 ZP 结合蛋白，并通过评估用 Hsp70 处理非获能精子后精子是否具有更高的受精能力（获能）来验证 Hsp70 的作用。 我们提出的工作结果可以转化为增强某些 ZP 结合蛋白水平较低的精子的受精能力。 它们将用 CLU + 所需的 ZP 结合蛋白以及 Hsp70 进行处理，以增强复合物的形成。 我们的研究还将更好地了解精子的成熟和获能过程。