SLO3 KO MOUSE: A TOOL TO REVEAL VOLTAGE-DEPENDENT PROCESSES IN SPERM FERTILITY

项目总结 全世界有10%到15%的夫妇受到不孕不育的影响，其中约50%是由男性因素造成的 案子。男性不育的诊断主要是根据标准精液分析的结果， 提供有关精子数量、形态和活力的信息。然而，许多来自中国的精子样本 不孕不育的男性通过了这一标准分析，但由于未知的原因，仍然缺乏使卵子受精的能力。 因此，为了提高男性的生育力，我们的长期目标是揭示精子 有能力使卵子受精，并确定新的诊断策略和治疗靶点。 在许多哺乳动物中，膜超极化(当细胞内电压变得更 (阴性)是精子有能力使卵子受精(获能)的关键事件。我们之前 显示缺乏精子特异性SLO3K+通道的小鼠的精子不能通过膜 超极化和不育。超极化也与人类精子获能有关， 而去极化的膜与人类精子的受精能力受损有关。然而， 负责调节人类精子膜电位的离子通道尚不确定。在这 我们的目标是确定人类细胞膜电位变化背后的离子通透性 精子和膜超极化如何调节细胞内钙的变化(另一个关键 精子获能方面)。我们认为人类精子膜电位受 小鼠精子中钾(K+)通道SLO_3及SLO_3功能障碍可能是 部分男性特发性不育病例。这些研究还可能产生一个有价值的临床工具-- 用电压敏感染料测量精子膜电位--预测人类精子 受精能力。此外，如果SLO_3在人类受精过程中发挥重要作用，就像它在人类受精过程中 在老鼠身上，这种精子特异性通道将为雄性提供一个新的非荷尔蒙靶标 避孕药。

PROJECT SUMMARY Infertility affects 10% to 15% of couples worldwide, and a male factor contributes to around 50% of these cases. Male infertility is diagnosed predominantly on the results of standard semen analysis, which provides information about sperm count, morphology, and motility. However, many sperm samples from infertile men pass this standard analysis but, for unknown reasons, still lack the ability to fertilize an egg. Thus, to improve male fertility, our long-term goal is to reveal the basic mechanisms by which sperm become competent to fertilize an egg and to identify new diagnostic strategies and therapeutic targets. In many mammalian species membrane hyperpolarization (when the intracellular voltage becomes more negative) is a key event in sperm becoming competent to fertilize an egg (capacitation). We previously showed that sperm from mice that lack the sperm-specific SLO3 K+ channels cannot undergo membrane hyperpolarization and are infertile. Hyperpolarization is also associated with human sperm capacitation, and a depolarized membrane is associated with impaired fertilization capacity in human sperm. However, the ion channels responsible for regulating membrane potential in human sperm are uncertain. In this proposal we aim to determine the ion permeabilities that underlie membrane potential changes in human sperm and how membrane hyperpolarization regulates changes in intracellular calcium (another key aspect of sperm capacitation). We propose that human sperm membrane potential is regulated by the potassium (K+) channel SLO3 as in mouse sperm and that SLO3 dysfunction might be responsible for some cases of male idiopathic infertility. These studies might also produce a valuable clinical tool – measurement of sperm membrane potential using voltage sensitive dyes - to predict human sperm fertilization capacity. Additionally, if SLO3 plays an essential role in human fertilization in humans as it does in mice, this sperm-specific channel would provide a new, non-hormonal target for a male contraceptive.