Analysis of an NHE inhibitor signaling pathway that regulates sperm motility.

调节精子活力的 NHE 抑制剂信号通路分析。

• 批准号: 7940333
• 负责人: PAUL F JAMES
• 金额: $ 42.6万
• 依托单位: MIAMI UNIVERSITY OXFORD
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7940333
• 关键词: Address; Adenylate Cyclase; Agreement; Binding; Camping; Cell Line; Cell model; Couples; Cultured Cells; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Ensure; Event; Fertility; Future; Goals; Human; Individual; Infertility; Investigation; Ion Channel Protein; Knock-out; Knockout Mice; Knowledge; Ligands; Link; Maintenance; Male Contraceptions; Measures; Mediating; Membrane Transport Proteins; Molecular; Motor; Mus; NHE1; PKA inhibitor; Pathway interactions; Phosphorylation; Physiology; Play; Protein Isoforms; Role; Series; Signal Pathway; Signal Transduction; Signaling Molecule; Sperm Motility; World Health Organization; cell motility; design; in vivo; inhibitor/antagonist; male; men; mouse model; public health relevance; receptor; research study; restoration; sperm cell

DESCRIPTION (provided by applicant): Acquisition and maintenance of motility are important components of sperm physiology in that they play critical roles in ensuring fertility. While the roles that structural/motor proteins and ion channels play in sperm motility is under intense investigation and is beginning to become clear, the roles that active membrane transporters play in regulating sperm motility is not as well understood. However, recent evidence suggests that the Na/H exchanger (NHE) is important in maintaining an optimal intracellular pH critical for sperm motility. In agreement with this hypothesis, knockout of the sperm-specific NHE, NHE10, results in immotile mouse sperm confirming a link between NHE activity and sperm motility. The motility of these NHE10 knockout sperm can be restored either by increasing intracellular pH or by increasing intracellular cAMP concentration. Our preliminary studies demonstrate that in order for cAMP to restore motility to acidified sperm, an active NHE is required. Towards defining which of the three sperm NHE isoforms is required for cAMP to restore motility, we made the exciting discovery that an inhibitor of the NHE, by itself, can completely restore motility to NHE10 knockout sperm. In the studies proposed here, we will define the intracellular signaling molecules participating in the Camp dependent, motility-restoring pathway activated by the NHE inhibitor, we will identify which of the three NHE found in sperm initiate this pathway, and which of these isoforms serves as the ultimate downstream effectors to restore motility. These studies will not only be important for defining the role that the NHEs play in regulating sperm motility but they also may have medically relevant implications: Human sperm also contains this NHE inhibitor initiated motility-regulating signaling pathway and therefore a subset of infertile men may be infertile due to disruption in this pathway and specific inhibitors or activators of this pathway could be developed as therapies for male fertility/infertility treatments. PUBLIC HEALTH RELEVANCE: It is well accepted that adequate sperm motility is one of the key components of male fertility. Individuals with poorly motile or immotile sperm are typically infertile. In the US alone an estimated 10-15% of couples are considered infertile as defined by World Health Organization criteria. Among them, it is estimated that 30% of these couples are infertile due to the male partner. Therefore, a thorough understanding of the molecular events that allows sperm to acquire and maintain motility will help us to address issues related to infertility associated with poorly motile or immotile sperm. In addition, the knowledge gained in understanding the molecules involved in maintaining sperm motility could be useful in developing targets for effective male contraception.

描述(由申请人提供)：获得和维持精子活力是精子生理学的重要组成部分，因为它们在确保生育能力方面起着关键作用。虽然结构/运动蛋白和离子通道在精子运动中的作用正在进行深入的研究，并开始变得清晰，但活性膜转运体在调节精子运动中所起的作用还不是很清楚。然而，最近的证据表明，Na/H交换器(NHE)在维持细胞内对精子活力至关重要的最佳pH中起着重要作用。与这一假设一致，敲除精子特异的NHE，NHE10，导致小鼠精子静止，证实了NHE活性和精子活力之间的联系。这些NHE10基因敲除的精子的活力可以通过提高细胞内pH或增加细胞内cAMP浓度来恢复。我们的初步研究表明，为了使cAMP恢复酸化精子的活力，需要活跃的NHE。为了确定三种精子NHE亚型中的哪一种是cAMP恢复活力所必需的，我们取得了令人兴奋的发现，NHE的抑制剂本身就可以完全恢复NHE10基因敲除的精子的活力。在这里提出的研究中，我们将定义参与cAMP依赖的、由NHE抑制剂激活的运动恢复途径的细胞内信号分子，我们将确定在精子中发现的三种NHE中的哪一种启动了这一途径，以及这些亚型中的哪一种是恢复运动的最终下游效应物。这些研究不仅对确定NHEs在调节精子运动中的作用具有重要意义，而且还可能具有医学上的相关意义：人类精子也包含NHE抑制剂启动的运动调节信号通路，因此，一部分不育男性可能由于这一通路的中断而不育，该通路的特异性抑制物或激活剂可能被开发为男性生育/不育治疗的治疗方法。 与公共卫生相关：人们普遍认为，充足的精子活力是男性生育能力的关键因素之一。精子运动能力差或不活动的个体通常是不育的。根据世界卫生组织的标准，仅在美国，估计就有10%-15%的夫妇被定义为不孕不育。其中，据估计，这些夫妇中有30%因男性伴侣而不育。因此，彻底了解精子获得和维持活力的分子事件将有助于我们解决与低活力或静止精子相关的不育症问题。此外，在了解与维持精子活力有关的分子方面获得的知识可能有助于开发有效的男性避孕目标。