Inhibitors of Na,K-ATPase alpha4 as male contraceptives

Na,K-ATP酶α4抑制剂作为男性避孕药

• 批准号: 8829881
• 负责人: V GUSTAVO BLANCO
• 金额: $ 23.49万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8829881
• 关键词: ATPase inhibitory protein; Adverse effects; Affect; Affinity; Binding Sites; Biochemical; Biological Availability; Biological Markers; Cardenolides; Cell membrane; Cells; Characteristics; Clinical; Contraceptive Agents; Contraceptive methods; Drug Kinetics; Drug Targeting; Ensure; Epididymis; Event; Fertility; Future; Germ Cells; Gland; Goals; Health; Human; In Vitro; Ions; Knock-out; Knowledge; Laboratories; Male Contraceptions; Male Contraceptive Agents; Male Infertility; Meiosis; Membrane Potentials; Membrane Transport Proteins; Metabolic; Molecular; Mus; Mutate; Na(+)-K(+)-Exchanging ATPase; Ouabain; Partner in relationship; Plasma; Population; Protein Inhibition; Proteins; Public Health; Rattus; Recombinants; Research; Resistance; Safety; Series; Somatic Cell; Specificity; Sperm Capacitation; Sperm Motility; Sperm Tail; Spermatogenesis; Sterility; Structure; Testing; Testis; Vertebral column; Wild Type Mouse; Woman; Work; analog; birth control; cell motility; contraceptive effectiveness; extracellular; improved; in vivo; inhibitor/antagonist; male; men; mouse model; pre-clinical; preclinical efficacy; programs; research study; scaffold; sperm cell; sperm function; unintended pregnancy

DESCRIPTION (provided by applicant): The rapidly growing world population and the high rate of unintended pregnancies make contraception a need and a priority for any public health program. While several contraceptive methods for women are currently available, a more comprehensive approach to birth control requires extending contraception to males. However, a safe, effective and reversible contraceptive for men is still unavailable. An attractive approach t develop male contraceptives consists in targeting proteins that are specifically expressed in sperm and are required for sperm fertility. Evidence from our laboratory has shown that Na,K-ATPase ¿4, a sperm specific plasma membrane transporter, which exchanges cytoplasmic Na+ for extracellular K+ is one of these attractive targets for male contraception. Na,K-ATPase ¿4 is only expressed in male germ cells of the testis after meiosis and abundant in the sperm flagellum. Importantly, ¿4 has functional characteristics that are highly unique and critical for sperm function. Activity of ¿4 is essential for maintaining sperm intracellular Na+ levels ([Na+]i) and several vital sperm parameters, including membrane potential (Vm), intracellular Ca+2 ([Ca2+]i) and pH. Importantly, ¿4 is crucial for sperm motility and hyperactivation, a key event associated with sperm capacitation. Accordingly, knockout of ¿4 in mice results in complete male infertility. From a biochemical standpoint, ¿4 has a particularly high affinity for the cardenolide ouabain. We have developed a series of synthetic compounds with steroidal and non-steroidal backbone structure, which, by targeting the ouabain binding site of ¿4, selectively inhibit ¿4 and affect sperm motility. These results provide strong evidence for the suitability of ¿4 as a pharmacological target for the control of male fertility. The key to targeting Na,K-ATPase ¿4 is that inhibition of this protein will allow to specifically interfere with sperm functin, without affecting spermatogenesis and providing temporary and reversible contraception. In addition, the lack of ¿4 in somatic cells reduces the chances that its inactivation will produce side effects. However, before the ¿4 inhibitors can be moved forward into their application as male contraceptives, it is necessary that their efficacy, drug-target interaction, biomarkers for their in vitro and vivo specificity, side effects and mechanisms of action are identified and optimized for future clinical use. We will test this here by determining the efficacy and selectiviy of action of our inhibitors on Na,K-ATPase ¿4 activity, on sperm motility and on sperm parameters that are controlled by Na,K-ATPase ¿4 activity, including sperm [Na+]i, [Ca2+]i, pH, Vm, sperm hyperactivation, motility and fertility. Finally, we will determine the pharmacokinetic parameters, safety and contraceptive effectiveness of Na,K-ATPase ¿4 inhibitors in mating trials in mice. The rationale for the research is that once the suitability of cardenolides as targets of Na,K-ATPase ¿4 is validated, both in vitro and in vivo, they can be advanced as agents for the reversible control of male fertility.

描述（由适用提供）：迅速增长的世界人口和意外怀孕的高率使避孕是任何公共卫生计划的需求和优先事项。虽然目前有几种妇女避孕方法，但采用更全面的节育方法需要向男性扩展避孕方法。但是，对于男性来说，一种安全，有效和可逆的避孕药仍然不可用。一种有吸引力的方法t开发雄性避孕药在于靶向精子中特异性表达的蛋白质，是精子生育所必需的。我们实验室的证据表明，Na，K-ATPase€4，一种精子特异性质膜转运蛋白，将细胞质Na+交换为细胞外K+是男性避孕的这些有吸引力的靶标之一。 Na，K-ATPase»4仅在减数分裂后的睾丸雄性细胞中表达，精子鞭毛中丰富。重要的是，„ 4具有高度独特且对精子功能至关重要的功能特征。 »4的活性对于维持精子内Na+水平（[Na+] i）至关重要 以及几个重要的精子参数，包括膜电位（VM），细胞内Ca+2（[Ca2+] I）和pH。重要的是，„ 4对于精子运动和过度激活至关重要，这是与精子电容相关的关键事件。根据敲除€4中的小鼠导致完全雄性不育症。从生化的角度来看，„ 4对Cardenolide Ouabain具有特别高的亲和力。我们已经开发了一系列具有类固醇和非甾体主链结构的合成化合物，这些化合物通过靶向4的Ouabain结合位点，有选择地抑制€4并影响精子运动。这些结果提供了有力的证据，证明„ 4作为控制男性生育能力的药物目标。靶向Na，K-ATPase»4的关键是，抑制该蛋白质将允许特异性干扰精子功能，而不会影响精子发生并提供暂时和可逆的隔离。此外，体细胞中缺乏4的缺乏减少了其失活会产生副作用的机会。但是，在可以将4种抑制剂转移到其作为男性避孕药中的应用中之前，必须将其有效性，药物目标相互作用，用于体外和体内特异性的生物标志物，副作用和作用机制进行确定，并优化，以实现未来的临床使用。我们将在此处通过确定抑制剂对Na，K-ATPase»4活性的有效性和选择性，对精子运动和由Na，K-ATPase»4个活性控制的精子参数，包括精子[Na+] I，[Ca2+] I，[Ca2+] I，PH，VM，VM，Sperm，Apperm，SpermExtivation，Motivation，Motitivation和Mortitivation。最后，我们将确定Na，K-ATPase»4抑制剂在小鼠的配位试验中的药代动力学参数，安全性和避孕有效性。该研究的理由是，一旦经过体外和体内，验证了Cardenolides作为Na，K-ATPase€4的靶标的适合性，就可以作为可逆控制男性生育能力的代理。