The biology of blood-testis barrier dynamics

血睾屏障动力学的生物学

• 批准号: 8081158
• 负责人: C. Yan Cheng
• 金额: $ 7.16万
• 依托单位: POPULATION COUNCIL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8081158
• 关键词: Address; Adult; Androgen Receptor; Androgens; Apical; Back; Basement membrane; Biochemical; Biochemistry; Biological; Biology; Blood-Testis Barrier; Cell Adhesion; Cell physiology; Cell surface; Cells; Cellular biology; Cicatrix; Coculture Techniques; Collagen; Endocytosis; Endosomes; Epithelial; Epithelium; Extracellular Matrix; Extracellular Matrix Proteins; Gelatinase B; Germ Cells; Homeostasis; In Vitro; Infertility; Integral Membrane Protein; Kinetics; Knockout Mice; Laboratories; Male Contraceptions; Male Contraceptive Agents; Male Infertility; Matrix Metalloproteinases; Mediating; Meiosis; Membrane Proteins; Metalloproteases; Molecular; Molecular Biology; Mus; Peptide Hydrolases; Permeability; Pharmaceutical Preparations; Production; Property; Protease Inhibitor; Proteins; Rattus; Recombinants; Recycling; Regulation; Research; Research Personnel; Site; Spermatocytes; Spermatogenesis; Staging; Study models; TNF gene; Techniques; Testing; Testis; Testosterone; Tight Junctions; Time; Tissue Inhibitor of Metalloproteinase-1; Tissues; Transforming Growth Factors; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors; Work; base; cell motility; cytokine; design; in vitro Model; in vivo; inhibitor/antagonist; innovation; insight; late endosome; leydig interstitial cell; migration; mouse model; novel; novel strategies; occludin; public health relevance; sertoli cell; spermatogenic epithelium structure; tool; transcytosis

DESCRIPTION (provided by applicant): The long-term objective of this proposal is to understand the biology and regulation of blood-testis barrier (BTB) dynamics during spermatogenesis using the adult rat testis as a study model. Specifically, it seeks to unravel the mechanism(s) that maintains BTB integrity as preleptotene and leptotene spermatocytes traverse the BTB that occurs at stage VIII of the seminiferous epithelial cycle of spermatogenesis. This study is important since it answers an open question in the field regarding the biochemical and/or molecular mechanism(s) utilized by the testis that regulates the timely 'restructuring' of the BTB to permit spermatocyte transit while maintaining the immunological barrier function at the BTB. This information is also helpful to develop innovative approaches to design new drugs (e.g., male contraceptives that exert their effects by disrupting germ cell function in the seminiferous epithelium) that can be targeted to the seminiferous epithelium behind the BTB. Recent studies have shown that cytokines (e.g., tumor necrosis factor ?, TNF?, and transforming growth factor-?2/-3, TGF-?2 or -?3) have a disruptive effect on BTB integrity, whereas testosterone promotes BTB function, illustrating that the opposing effects of these molecules are crucial to maintain the timely "opening" and "closing" of the BTB during spermatogenesis while facilitating germ cell movement across the barrier. Since both TNF? and TGF-?3 are products of Sertoli and germ cells, and testosterone is a product of Leydig cells (but the androgen receptor resides mostly on the Sertoli cell), in the testis, it is likely that these molecules are released into the BTB microenvironment during spermatogenesis to regulate BTB dynamics. In this application, the P.I. will examine the hypothesis that TNF? regulates BTB dynamics via its effects on basement membrane proteins, such as collagens, proteases and protease inhibitors, which, in turn, regulates the steady-state levels of integral membrane proteins at the BTB. This will determine the status of the BTB to facilitate or prohibit the transit of preleptotene/leptotene spermatocytes across the barrier (Specific Aim 1). Furthermore, the P.I. will test the hypothesis that cytokines and testosterone mediate their opposing effects on the BTB via their differential actions on endocytosis, recycling, endosome-mediated intracellular degradation and transcytosis/relocation of integral membrane proteins at the BTB (Specific Aim 2). The proposed studies will be performed using cutting-edge techniques of biochemistry, molecular biology, and cell biology. The P.I. will also develop and characterize a novel in vitro model using Sertoli-germ cell cocultures to investigate the regulation of germ cell movement across the BTB, which can become a valuable research tool for investigators in the field. In short, this proposal addresses a long-standing mystery in spermatogenesis regarding the biology and regulation of the BTB during the epithelial cycle. PUBLIC HEALTH RELEVANCE: This project seeks to understand the mechanism(s) that regulates blood-testis barrier (BTB) dynamics during the seminiferous epithelial cycle of spermatogenesis using the adult rat testis as a study model. The BTB must `open' or `restructure' transiently during spermatogenesis to facilitate the transit of spermatocytes across the barrier. This, in turn, poses a unique opportunity to transport a drug, such as a male contraceptive that disrupts cell adhesion, behind the BTB to exert its effects, if the mechanism(s) that regulates the timely opening of the BTB is known. In short, this proposal seeks to understand the biology of BTB dynamics during spermatogenesis. It also offers new insight into: (i) developing novel approaches for male contraception, and (ii) the causes of unexplained male infertility.

描述（由申请人提供）：该提案的长期目标是了解使用成年大鼠睾丸作为研究模型的精子发生过程中血液尾屏障（BTB）动力学的生物学和调节。具体而言，它试图揭示作为前肽和瘦素精子细胞在精子发生的eminiferial上皮周期的VIII中遍布BTB完整性的机制。这项研究很重要，因为它回答了睾丸利用的关于生化和/或分子机制的一个公开问题，该睾丸使用的生化和/或分子机制调节BTB的及时“重组”以允许精子过渡，同时保持BTB的免疫障碍功能。这些信息也有助于开发创新的方法来设计新药（例如，通过破坏生殖细胞上皮中的生殖细胞功能发挥其作用的新药物），可以针对BTB后面的生精上皮。最近的研究表明，细胞因子（例如，肿瘤坏死因子？，TNF？，转化生长因子 - ？2/-3，TGF-？2或 - ？3）对BTB完整性具有破坏性作用，而睾丸激素却促进了BTB的功能，表明在这些分子的相对效应中，这些分子在近距离上保持了近距离的影响。同时促进横跨屏障的生殖细胞运动。既然TNF？ tgf-？3是否是塞托利和生殖细胞的产物，睾丸激素是睾丸中的leydig细胞的产物（但雄激素受体主要驻留在塞托利细胞上），在睾丸中，这些分子很可能被释放到BTB微环境中，以调节BTB动力学。在此应用程序中会检查TNF的假设吗？通过其对基底膜蛋白（例如胶原蛋白，蛋白酶和蛋白酶抑制剂）的影响来调节BTB动力学，从而调节BTB处整体膜蛋白的稳态水平。这将确定BTB的状态，以促进或禁止在整个屏障跨屏障跨肽/瘦素精子细胞的转运（特定目标1）。此外，P.I.将检验以下假设：细胞因子和睾丸激素通过其对内吞作用，回收，内体介导的细胞内降解和整体膜膜蛋白在BTB处的跨性质降解和转移/重新分配的差异作用来介导其对BTB的相对影响（特定目标2）。拟议的研究将使用生物化学，分子生物学和细胞生物学的尖端技术进行。 P.I.还将使用Sertoli-Germ细胞共培养来开发并表征一种新型的体外模型，以调查BTB跨BTB的生殖细胞运动的调节，这可以成为该领域研究人员的宝贵研究工具。简而言之，该提案解决了关于上皮周期中BTB的生物学和调节的精子发生的长期谜团。公共卫生相关性：该项目旨在了解使用成年大鼠睾丸作为研究模型的精子发生中的精子发生中的精子生成中调节血液堵塞屏障（BTB）动态的机制。 BTB必须在精子发生过程中暂时“打开”或“重组”，以促进精子跨屏障的过渡。反过来，这又为运输药物提供了独特的机会，例如破坏细胞粘附的男性避孕药，如果已知的机制是及时开放BTB的机制，则在BTB后面发挥其作用。简而言之，该提议旨在了解精子发生过程中BTB动力学的生物学。它还提供了有关：（i）开发新型男性避孕方法的新见解，以及（ii）无法解释的男性不育症的原因。