精子特异性KSper钾通道在男性不育中的作用与机制

Malfunction of sperm is the major cause of male infertility, thus revealing the molecular mechanisms by which sperm functions are regulated is fundamentally important to clarify the pathology of male infertility. The applicant’s published work in mouse models has proved that the sperm-specific KSper potassium channel is a critical molecule for sperm function regulation. However, the physiological roles of human KSper and its relationship with male infertility still remain unclear. Our preliminary data showed that antibody on LRRC52, which is the associated subunit to form KSper, significantly inhibited the motility and acrosome reaction of human sperm. Furthermore, infertile human sperm samples with low KSper current amplitudes exhibited decreased sperm motility. Thus, we hypothesize that KSper is important for sperm functions such as motility and the abnormality of KSper may cause male infertility. Utilizing the KSper-deficient human sperm samples and combining with multiple technologies such as sperm patch clamping and calcium imaging, this project aims to: 1) Investigating the molecular defects causing the decreased KSper amplitudes; 2) Revealing the signaling mechanisms by which KSper modulates sperm motility; 3)Verifying the importance of KSper malfunction in male infertility. The completion of this project may systematically clarify the physiological and pathological roles of KSper in human sperm, offering a novel molecular target for male infertility diagnosis and treatment.

精子功能障碍是导致男性不育的主要原因，揭示精子功能调控的分子机制是阐明男性不育病理机制的基础。申请人已发表的小鼠模型工作表明，精子特异性钾离子通道KSper是调控精子功能的重要分子。然而，有关人精子中KSper通道的生理功能、其异常与男性不育的相关性远未阐明。本申请前期工作表明，抗KSper组分LRRC52抗体显著抑制人精子运动与顶体反应，而从不育患者所筛选出的KSper电流低下的精子样本运动能力显著下降。故此我们假设KSper是调控精子运动等功能的关键分子、其异常导致男性不育。利用KSper电流低下人精子样本，结合精子膜片钳、胞内荧光测钙等技术，本申请拟：1）阐明导致KSper电流低下的可能原因；2）揭示KSper调控精子运动等功能的具体机制；3）进一步验证KSper异常在男性不育中的作用。本课题有望系统阐明人精子KSper的生理功能与病理作用，从而为男性不育的精准诊断与治疗提供新靶点。

男性不育已成为阻碍社会经济发展的重大疾病，揭示精子功能调控的分子机制是阐明男性不育病理机制的基础。虽然精子特异性钾离子通道KSper对精子功能调控的重要性已在小鼠模型中证实，有关人精子中KSper的调节机制与生理功能仍未阐明。针对这一问题，利用精子膜片钳、钙信号测量等手段，本项目主要从三个方面开展了研究：pH、胞内钙离子浓度对KSper的调控特征；KSper对精子钙信号与精子功能的调控作用；KSper异常与男性不育的相关性。相应的，主要结果包括：1）证实钠氢交换器通过调节胞内pH与KSper功能偶联；2）静息状态下的胞内钙离子与生理浓度孕酮刺激导致的胞内钙离子浓度增加均可激活KSper；3）KSper辅助亚基LRRC52特异性抗体显著抑制人精子运动和顶体反应率、降低人精子胞内钙离子浓度；4）抑制KSper或KSper表达低下导致孕酮所诱导人精子钙信号显著降低；5）小规模样本分析显示KSper缺失或表达低下与临床男性不育存在正相关性。这些工作从机制上揭示了人精子KSper与钙信号、pH之间复杂的相互作用关系，同时表明KSper是人精子功能重要的调控分子、也是男性不育靶分子。在基金资助下，已发表8篇SCI论文，两篇主要论文投稿中；授权专利两项，实审专利两项。