Gene Expression and Protein Synthesis in Mitochondria Enhance the Duration of High-Speed Linear Motility in Boar Sperm
Gene Expression and Protein Synthesis in Mitochondria Enhance the Duration of High-Speed Linear Motility in Boar Sperm
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DOI：
10.3389/fphys.2019.00252
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发表时间：
2019-03
影响因子：
4
通讯作者：
Zhendong Zhu;Zhendong Zhu;T. Umehara;T. Okazaki;M. Goto;Y. Fujita;S. A. M. Hoque;S. A. M. Hoque;T. Kawai;W. Zeng;M. Shimada
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文献类型：
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作者：
Zhendong Zhu;Zhendong Zhu;T. Umehara;T. Okazaki;M. Goto;Y. Fujita;S. A. M. Hoque;S. A. M. Hoque;T. Kawai;W. Zeng;M. Shimada
从射精到受精后，精子的运动模式在女性体内不断变化。在体外，高糖介质或体内输卵管液可诱导精子的高度激活运动，而精子在精浆或低葡萄糖的宫腔液中保持线性运动。因此，据估计，精子的运动模式依赖于能源，在低糖条件下，线粒体的氧化磷酸化被激活以产生ATP。为了阐明这些假设，猪精子在体外与转录和翻译抑制剂一起在不同的能量条件下孵育。分析精子运动参数、线粒体活性、三磷酸腺苷水平、基因表达和蛋白质合成。随着培养液中葡萄糖浓度的降低，精子前向运动速度和直线运动速度显著增加。此外，精子中线粒体基因组的转录和翻译的线粒体蛋白质周转在孵化过程中被激活。用线粒体翻译抑制剂(D-氯霉素)孵育精子，可抑制精子线粒体蛋白合成、线粒体活性和ATP水平，从而降低精子的线运动速度，但不影响精子的运动能力。这说明精子中线粒体的中枢活动是活跃的，在低糖条件下，通过激活线粒体生成ATP的活性，可以诱导精子的高速直线运动。
Sperm motility patterns are continuously changed after ejaculation to fertilization in the female tract. Hyperactivated motility is induced with high glucose medium in vitro or the oviduct fluids in vivo, whereas sperm maintain linear motility in the seminal plasma or the uterine fluids containing low glucose. Therefore, it is estimated that sperm motility patterns are dependent on the energy sources, and the mitochondrial oxidative phosphorylation is activated to produce ATP in low glucose condition. To elucidate these hypotheses, boar sperm was incubated in different energy conditions with the transcription and translation inhibitors in vitro. Sperm motility parameters, mitochondrial activity, ATP level, gene expression and protein synthesis were analyzed. Sperm progressive motility and straight-line velocity were significantly increased with decreasing glucose level in the incubation medium. Moreover, the mitochondrial protein turnover meaning transcription and translation from mitochondrial genome in sperm is activated during incubation. Incubation of sperm with mitochondrial translation inhibitor (D-chloramphenicol) suppressed mitochondrial protein synthesis, mitochondrial activity and ATP level in sperm and consequently reduced the linear motility speed, but not the motility. Thus, it is revealed that the mitochondrial central dogma is active in sperm, and the high-speed linear motility is induced in low glucose condition via activating the mitochondrial activity for ATP generation.