National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science of South China Agricultural University, Guangzhou 510642, China.
Int J Mol Sci. 2022 Aug 21;23(16):9441. doi: 10.3390/ijms23169441.
In mammals, β-defensins have been reported to play pivotal roles in sperm protection and fertilization. However, the function and mechanism of porcine β-defensin 129 (pBD129) in the sperm remain unclear. Here, we demonstrate that pBD129 is a glycosylated protein and broadly exists in accessory sex glands and coats the sperm surface. We inhibited the pBD129 protein on the sperm surface with an anti-pBD129 antibody and found that sperm motility was not significantly affected; however, sperm acrosome integrity and tyrosine phosphorylation levels increased significantly with time (p < 0.05) during capacitation. These changes were accompanied by an increase in sperm Ca2+ influx, resulting in a significantly reduced in vitro fertilization cleavage rate (p < 0.05). Further investigation revealed that treatment with recombinant pBD129 markedly restored the sperm motility in semen contaminated with Escherichia coli. The results suggest that pBD129 is not only associated with poor sperm motility after genital tract infection but can also protect the spermatozoa from premature capacitation, which may be beneficial for semen preservation.
在哺乳动物中，β-防御素被报道在精子保护和受精中发挥关键作用。然而，猪β-防御素 129（pBD129）在精子中的功能和机制尚不清楚。在这里，我们证明 pBD129 是一种糖基化蛋白，广泛存在于附属生殖腺和精子表面。我们用抗 pBD129 抗体抑制精子表面的 pBD129 蛋白，发现精子的运动能力没有明显受到影响；然而，在获能过程中，精子顶体完整性和酪氨酸磷酸化水平随时间显著增加（p<0.05）。这些变化伴随着精子 Ca2+内流的增加，导致体外受精的卵裂率显著降低（p<0.05）。进一步的研究表明，重组 pBD129 处理显著恢复了精液中污染大肠杆菌的精子运动能力。结果表明，pBD129 不仅与生殖道感染后精子运动能力差有关，而且还可以保护精子免受过早获能，这可能有利于精液保存。
