Laboratory of Veterinary Physiology, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan.
Cell Mol Life Sci. 2021 Mar;78(6):2929-2948. doi: 10.1007/s00018-020-03683-9. Epub 2020 Oct 26.
Macrophages are innate immune cells that contribute to classical immune functions and tissue homeostasis. Ubiquitin-specific protease 2 (USP2) controls cytokine production in macrophages, but its organ-specific roles are still unknown. In this study, we generated myeloid-selective Usp2 knockout (msUsp2KO) mice and specifically explored the roles of testicular macrophage-derived USP2 in reproduction. The msUsp2KO mice exhibited normal macrophage characteristics in various tissues. In the testis, macrophage Usp2 deficiency negligibly affected testicular macrophage subpopulations, spermatogenesis, and testicular organogenesis. However, frozen-thawed sperm derived from msUsp2KO mice exhibited reduced motility, capacitation, and hyperactivation. In addition, macrophage Usp2 ablation led to a decrease in the sperm population exhibiting high intracellular pH, calcium influx, and mitochondrial membrane potential. Interrupted pronuclei formation in eggs was observed when using frozen-thawed sperm from msUsp2KO mice for in vitro fertilization. Administration of granulocyte macrophage-colony stimulating factor (GM-CSF), whose expression was decreased in testicular macrophages derived from msUsp2KO mice, restored mitochondrial membrane potential and total sperm motility. Our observations demonstrate a distinct role of the deubiquitinating enzyme in organ-specific macrophages that directly affect sperm function.
巨噬细胞是先天免疫细胞，有助于经典的免疫功能和组织稳态。泛素特异性蛋白酶 2（USP2）控制巨噬细胞中的细胞因子产生，但它在器官特异性中的作用尚不清楚。在这项研究中，我们生成了髓系选择性 USP2 敲除（msUsp2KO）小鼠，并专门探讨了睾丸巨噬细胞来源的 USP2 在生殖中的作用。msUsp2KO 小鼠在各种组织中表现出正常的巨噬细胞特征。在睾丸中，巨噬细胞 USP2 缺乏对睾丸巨噬细胞亚群、精子发生和睾丸发生的影响可以忽略不计。然而，来自 msUsp2KO 小鼠的冻融精子表现出运动能力、顶体反应和超激活能力降低。此外，巨噬细胞 USP2 缺失导致具有高细胞内 pH 值、钙离子内流和线粒体膜电位的精子数量减少。当使用来自 msUsp2KO 小鼠的冻融精子进行体外受精时，观察到卵中的原核形成中断。GM-CSF（GM-CSF）的给药，其表达在 msUsp2KO 小鼠的睾丸巨噬细胞中降低，恢复了线粒体膜电位和总精子活力。我们的观察结果表明，去泛素化酶在器官特异性巨噬细胞中具有独特的作用，直接影响精子功能。
