Secretory phospholipase A2 group IID Is involved in progesterone-induced acrosomal exocytosis of human spermatozoa.
Secretory phospholipase A2 group IID Is involved in progesterone-induced acrosomal exocytosis of human spermatozoa.
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DOI：
10.2164/jandrol.111.014886
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发表时间：
2012-09
影响因子：
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通讯作者：
Kun Li;Jian-Yuan Jin;Wenying Chen;Q. Shi;Y. Ni;E. Roldan
中科院分区：
文献类型：
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作者：
Kun Li;Jian-Yuan Jin;Wenying Chen;Q. Shi;Y. Ni;E. Roldan
磷脂酶A2（PLA（2））在哺乳动物精子顶体胞吐过程中起重要作用，但PLA（2）亚型的鉴定仍不清楚。本研究探讨了人类精子中是否存在分泌型PLA（2）IID组（sPLA（2）-IID）亚型以及它是否参与AE。用免疫荧光染色和Western blot分析方法研究sPLA（2）-IID在人精子中的定位和表达。通过三重染色评价AE的发生，并通过气相色谱-质谱法定量花生四烯酸（AA）水平。精子运动参数和超激活进行了分析，通过计算机辅助精子分析。sPLA（2）-IID定位于人精子头部顶体后区和尾部中段。Western blotting检测到一条16 kd的蛋白带。使用sPLA（2）-IID中和抗体，孕酮诱导的AE以浓度依赖性方式显著抑制。在甾醇刺激的胞吐作用期间观察到的AA水平的增加被抗体显著消除。sPLA（2）-IID抗体显著抑制精子的超活化、精子曲线运动速度和头部侧向位移幅度，但不影响活动精子的比例。总之，sPLA（2）-IID存在于人精子的头部和中段，并且这种sPLA（2）-IID的活化似乎与AE有关。因此，sPLA（2）-IID亚型在人精子AE过程中发挥功能性作用。
Phospholipase A2 (PLA(2)) plays a major role during acrosomal exocytosis (AE) in mammalian spermatozoa, but the identity of PLA(2) subtypes present in spermatozoa remains elusive. This study explored whether secretory PLA(2) Group IID (sPLA(2)-IID) isoform is present in human spermatozoa and whether it is involved in AE. Localization and expression of sPLA(2)-IID in human spermatozoa were explored by immunofluorescence staining and Western blot analysis. Occurrence of AE was evaluated by triple staining, and arachidonic acid (AA) levels were quantified by gas chromatography-mass spectrometry. Sperm motion parameters and hyperactivation were analyzed by computer-assisted sperm analysis. sPLA(2)-IID was localized in the postacrosomal region of the head and the midpiece of tail in human sperm. A 16-kd protein band was detected by Western blotting in sperm extracts. Progesterone-induced AE was significantly inhibited in a concentration-dependent manner using a sPLA(2)-IID neutralizing antibody. The increase in AA levels seen during progesterone-stimulated exocytosis was significantly abrogated by the antibody. The sPLA(2)-IID antibody significantly inhibited hyperactivation, sperm curvilinear velocity, and amplitude of lateral head displacement, but it did not affect the proportion of motile sperm. In conclusion, sPLA(2)-IID is present at the head and midpiece in the human sperm, and activation of such sPLA(2)-IID seems to be involved in AE. Therefore, sPLA(2)-IID isoform plays a functional role during the AE in human sperm.