Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, Mexico.
J Cell Physiol. 2013 Mar;228(3):590-601. doi: 10.1002/jcp.24166.
Mammalian sperm must undergo a maturational process, named capacitation, in the female reproductive tract to fertilize the egg. Sperm capacitation is regulated by a cAMP/protein kinase A (PKA) pathway and involves increases in intracellular Ca(2+), pH, Cl(-), protein tyrosine phosphorylation, and in mouse and some other mammals a membrane potential hyperpolarization. The cystic fibrosis transmembrane conductance regulator (CFTR), a Cl(-) channel modulated by cAMP/PKA and ATP, was detected in mammalian sperm and proposed to modulate capacitation. Our whole-cell patch-clamp recordings from testicular mouse sperm now reveal a Cl(-) selective component to membrane current that is ATP-dependent, stimulated by cAMP, cGMP, and genistein (a CFTR agonist, at low concentrations), and inhibited by DPC and CFTR(inh) -172, two well-known CFTR antagonists. Furthermore, the Cl(-) current component activated by cAMP and inhibited by CFTR(inh) -172 is absent in recordings on testicular sperm from mice possessing the CFTR ΔF508 loss-of-function mutation, indicating that CFTR is responsible for this component. A Cl(-) selective like current component displaying CFTR characteristics was also found in wild type epididymal sperm bearing the cytoplasmatic droplet. Capacitated sperm treated with CFTR(inh) -172 undergo a shape change, suggesting that CFTR is involved in cell volume regulation. These findings indicate that functional CFTR channels are present in mouse sperm and their biophysical properties are consistent with their proposed participation in capacitation.
哺乳动物精子必须在雌性生殖道中经历一个成熟过程，称为获能，才能使卵子受精。精子获能受 cAMP/蛋白激酶 A (PKA) 途径调控，涉及细胞内 Ca(2+)、pH、Cl(-)、蛋白酪氨酸磷酸化的增加，以及在小鼠和其他一些哺乳动物中膜电位的超极化。囊性纤维化跨膜电导调节因子 (CFTR) 是一种受 cAMP/PKA 和 ATP 调节的 Cl(-) 通道，在哺乳动物精子中被检测到，并被提议调节获能。我们现在从睾丸小鼠精子进行的全细胞膜片钳记录揭示了一种 Cl(-) 选择性膜电流成分，该成分对 cAMP、cGMP 和染料木黄酮（CFTR 激动剂，低浓度时）敏感，对 DPC 和 CFTR(inh) -172 敏感，CFTR(inh) -172 是两种众所周知的 CFTR 拮抗剂。此外，cAMP 激活和 CFTR(inh) -172 抑制的 Cl(-) 电流成分在 CFTR ΔF508 失活突变小鼠睾丸精子的记录中不存在，表明 CFTR 负责该成分。在携带细胞质液滴的野生型附睾精子中也发现了具有 CFTR 特征的 Cl(-) 选择性类似电流成分。用 CFTR(inh) -172 处理获能的精子会发生形态变化，表明 CFTR 参与细胞体积调节。这些发现表明功能性 CFTR 通道存在于小鼠精子中，它们的生物物理特性与其在获能中的参与一致。
