Torrezan-Nitao Elis, Boni Raianna, Marques-Santos Luis Fernando
Laboratório de Biologia Celular e do Desenvolvimento, Departamento de Biologia Molecular, Universidade Federal da Paraíba, Campus I, Cidade Universitária, CEP: 58051-900, João Pessoa, Paraíba, Brazil.
Cell Biol Int. 2016 Oct;40(10):1071-83. doi: 10.1002/cbin.10647. Epub 2016 Aug 3.
Mitochondrial permeability transition pore (MPTP) is a protein complex whose opening promotes an abrupt increase in mitochondrial inner membrane permeability. Calcium signaling pathways are described in gametes and are involved in the fertilization process. Although mitochondria may act as Ca(2+) store and have a fast calcium-releasing mechanism through MPTP, its contribution to fertilization remains unclear. The work aimed to investigate the MPTP phenomenon in sea urchin spermatozoa and its role on the fertilization. Several pharmacological tools were used to evaluate the MPTP's physiology. Our results demonstrated that MPTP occurs in male gametes in a Ca(2+) - and voltage-dependent manner and it is sensitive to cyclosporine A. Additionally, our data show that MPTP opening does not alter ROS generation in sperm cells. Inhibition of MPTP in spermatozoa strongly improved the fertilization rate, which may involve mechanisms that increase the spermatozoa lifespan. The present work is the first report of the presence of a voltage- and Ca(2+) -dependent MPTP in gametes of invertebrates and indicates MPTP opening as another evolutionary feature shared by sea urchins and mammals. Studies about MPTP in sea urchin male gametes may contribute to the elucidation of several mechanisms involved in sperm infertility.
线粒体通透性转换孔（MPTP）是一种蛋白质复合物，其开放会促使线粒体内膜通透性突然增加。钙信号通路在配子中有所描述，并且参与受精过程。尽管线粒体可能充当钙库并具有通过MPTP的快速钙释放机制，但其对受精的作用仍不清楚。这项工作旨在研究海胆精子中的MPTP现象及其在受精中的作用。使用了几种药理学工具来评估MPTP的生理学特性。我们的结果表明，MPTP以钙和电压依赖性方式出现在雄配子中，并且对环孢素A敏感。此外，我们的数据表明，MPTP的开放不会改变精子细胞中活性氧的产生。抑制精子中的MPTP可显著提高受精率，这可能涉及延长精子寿命的机制。本研究首次报道了无脊椎动物配子中存在电压和钙依赖性MPTP，并表明MPTP的开放是海胆和哺乳动物共有的另一个进化特征。关于海胆雄配子中MPTP的研究可能有助于阐明与精子不育相关的几种机制。
