Role of epididymal macrophages and dendritic cells in male reproductive function

 描述（由申请方提供）：精子在附睾中转运期间获得活力和受精卵能力;睾丸后精子成熟和储存涉及附睾粘膜介导的机制。男性生殖生理学中最有趣和研究不足的方面之一是流出道阻止针对数百万自身抗原性生精细胞和成熟精子的自身免疫反应的发展，同时启动针对病原微生物的非常有效的免疫反应的能力。本申请集中于巨噬细胞（MΦ）和树突状细胞（DC）在建立精子成熟和储存的保护性环境中的作用。MΦ和DC是两个密切相关且极其通用的细胞家族，其在免疫应答的启动和调节中起关键作用。我们先前已经表明，附睾由表达MΦ和DC标志物的单核吞噬细胞（MP）的密集和异质网络构成;在近端附睾中，它们与附睾上皮细胞建立了密切的相互作用，并且是血液-附睾屏障的一部分。因此，它们在控制男性生殖功能方面具有重要的战略地位。我们推测，MΦ和DC合作调查两侧的血-附睾屏障，以调节免疫耐受和炎症之间的平衡，在睾丸后环境。在具体目标1中，我们表征了管腔抗原摄取，并通过诱导特定的调节性T淋巴细胞亚群（Tlymphocyte）来阐明对精子抗原耐受的机制。在具体目标2中，我们将通过测量局部毛细血管来确定MΦ和DC如何防止循环病原体影响精子。这两个目标都将依赖于使用最先进的显微镜成像程序（3D激光扫描共聚焦显微镜和双光活体显微镜），转基因小鼠模型和免疫学技术（例如流式细胞术分析，串扰分析，以表征MP和T细胞相互作用）很少用于生殖生理学。该项目的最终目标是为治疗男性免疫性不育症（一个主要的公共卫生问题）提供新的框架，反过来，通过免疫避孕控制男性生育力。

 DESCRIPTION (provided by applicant): Sperm acquire motility and the ability to fertilize and egg during their transit in the epididymis; post testicular sperm maturation and storage involve mechanisms mediated by the epididymal mucosa. One of the most intriguing and understudied aspects of male reproductive physiology is the ability of the excurrent duct to prevent the development of autoimmune responses against millions of autoantigenic spermatogenic cells and mature spermatozoa, meanwhile initiating very efficient immune responses against pathogenic microorganisms. The present application is focused on the role of macrophages (MΦ) and dendritic cells (DCs) in establishing the protective environment in which spermatozoa mature and are stored. MΦ and DCs are two closely related and extremely versatile families of cells that play critical roles in the initiation and regulation of immune responses. We have previously shown that the epididymis is populated by a dense and heterogeneous network of mononuclear phagocytes (MPs) expressing MΦ and DC markers; in the proximal epididymis, they establish intimate interactions with epididymal epithelial cells and are part of the blood- epididymis barrier. Therefore, they are strategically positioned to play a major role in the contro of male reproductive function. We hypothesize that MΦ and DCs cooperate to survey both sides of the blood- epididymis barrier to regulate the balance between immune tolerance and inflammation in the post-testicular environment. In Specific Aim 1, we characterize luminal antigen uptake and elucidate the mechanisms underlying tolerance to sperm antigens via the induction of a specific subset of regulatory T lymphocytes (Tregs). In Specific Aim 2, we will determine how MΦ and DCs prevent circulating pathogens from affecting spermatozoa by surveying local capillaries. Both aims will rely on the use of state-of-the-art microscopy imaging procedures (3D laser scanning confocal microscopy and two-photo intravital microscopy), transgenic mouse models, and immunological techniques (e.g. flow cytometry analysis, cross-talk assays to characterize MPs and T cell interactions) rarely used in reproductive physiology. The ultimate goal of this project is to provide new frameworks for the treatment of male immunological infertility (a major public health issue) and, conversely, for the control of male fertility via immunocontraception.