Effect of cariporide on ram sperm pH regulation and motility: possible role of NHE1
Effect of cariporide on ram sperm pH regulation and motility: possible role of NHE1
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DOI：
10.1530/rep-17-0456
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发表时间：
2018-05-01
期刊：
影响因子：
3.8
通讯作者：
Ciani, Elena
中科院分区：
文献类型：
--
作者：
Muzzachi, Stefania;Guerra, Lorenzo;Ciani, Elena
精子活力是体内受精的重要特征，受细胞内pH（pHi）稳态的影响。有几种机制参与pHi调节，其中钠-氢交换剂（NHE）是一个完整的跨膜蛋白家族，催化Na+交换为H+穿过脂质双层。NHE活性和动力学参数的初步表征，然后通过分析的表达和定位的蛋白质在公羊精子进行。NHE活性表明，外部Na+的表观Km为17.61 mM。免疫印迹显示分子量为85 kDa。免疫定位模式显示出种属特异性，如精子头部赤道区的阳性标记。Cariporide是一种选择性NHE 1抑制剂，可显著降低pHi恢复率（85%）。同样，暴露于cariporide显着抑制不同的运动参数，包括那些与精子获能。体外受精（IVF）不受Cariporide的影响，可能是由于运动性和速度参数的非戏剧性（尽管显著）下降，或由于IVF期间的长时间暴露，这可能导致其抑制作用的进行性丧失。总之，这是第一个研究记录，在一个大型动物模型（羊）的众所周知的翻译相关性，直接功能的作用，NHE精子pHi和运动。假设cariporide对Na+/H+交换体亚型1的特异性似乎表明NHE 1可能有助于观察到的对精子功能的影响。
Sperm motility, a feature essential for in vivo fertilization, is influenced by intracellular pH (pHi) homeostasis. Several mechanisms are involved in pHi regulation, among which sodium-hydrogen exchangers (NHEs), a family of integral transmembrane proteins that catalyze the exchange of Na+ for H+ across lipid bilayers. A preliminary characterization of NHE activity and kinetic parameters, followed by analysis of the expression and localization of the protein in ram spermatozoa was performed. NHE activity showed an apparent Km for external Na+ of 17.61 mM. Immunoblotting revealed a molecular mass of 85 kDa. Immunolocalization pattern showed some species-specific aspects, such as positive labeling at the equatorial region of the sperm head. Cariporide, a selective NHE1 inhibitor, significantly reduced pHi recovery (85%). Similarly, exposure to cariporide significantly inhibited different motility parameters, including those related to sperm capacitation. In vitro fertilization (IVF) was not affected by cariporide, possibly due to the non-dramatic, although significant, drop in motility and velocity parameters or due to prolonged exposure during IVF, which may have caused progressive loss of its inhibitory effect. In conclusion, this is the first study documenting, in a large animal model (sheep) of well-known translational relevance, a direct functional role of NHE on sperm pHi and motility. The postulated specificity of cariporide toward isoform 1 of the Na+/H+ exchanger seems to suggest that NHE1 may contribute to the observed effects on sperm cell functionality.