Sichuan Provincial Key Laboratory for Human Disease Gene Study and the Center for Medical Genetics, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology, Chengdu 610072, China; Key Laboratory of Reproductive Medicine, Center of Reproductive Medicine, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu 610045, China.
Key Laboratory of Reproductive Medicine, Center of Reproductive Medicine, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu 610045, China.
Reprod Biol. 2024 Jun;24(2):100881. doi: 10.1016/j.repbio.2024.100881. Epub 2024 May 20.
Infertility poses a global health and social challenge, affecting approximately 15% of couples at childbearing age, with half of the cases attributed to male factors, wherein genetic factors exert a substantial role. In our prior investigation, we identified loss-of-function variants within the gene encoding glutamine-rich protein 2 (QRICH2) in two consanguineous families, leading to various morphological abnormalities in sperm flagella and male infertility. Moreover, our observations in Qrich2 knockout mice revealed a pronounced reduction in spermatozoa count. However, the underlying mechanism remains elusive, prompting further investigation in the current study. By conducting experiments such as Hematoxylin-eosin (HE) staining, immunofluorescence staining, flow cytometry, and single sperm metabolism analysis on the testes and spermatozoa of Qrich2 knockout mice, we found a strong antioxidant capacity mediated by QRICH2 both in vivo and in vitro. Qrich2 knockout led to elevated levels of ROS, consequently inducing DNA damage in spermatids, which in turn triggered increased autophagy and apoptosis, ultimately causing a significant decrease in spermatozoa count. Incubation with the N-terminal purified protein of QRICH2 exhibited potent strong antioxidant activity at the cell and spermatozoa levels in vitro, thereby enhancing spermatozoa viability and motility. Therefore, QRICH2 plays a crucial role in safeguarding spermatids from excessive ROS-induced damage by augmenting antioxidant capacity, thereby promoting spermatozoa survival and improving motility. Furthermore, the N-terminal purified protein of QRICH2 shows promise as an additive for protecting spermatozoa during preservation and cryopreservation.
不育症是一个全球性的健康和社会挑战，影响了大约 15%的育龄夫妇，其中一半的病例归因于男性因素，遗传因素在其中发挥了重要作用。在我们之前的研究中，我们在两个近亲结婚的家庭中发现了编码富含谷氨酰胺的蛋白 2（QRICH2）的基因中的功能丧失变异，导致精子鞭毛的各种形态异常和男性不育。此外，我们在 Qrich2 敲除小鼠中的观察结果显示精子数量明显减少。然而，其潜在机制仍不清楚，促使我们在当前研究中进一步研究。通过对 Qrich2 敲除小鼠的睾丸和精子进行苏木精-伊红（HE）染色、免疫荧光染色、流式细胞术和单个精子代谢分析等实验，我们发现 QRICH2 在体内和体外都具有很强的抗氧化能力。Qrich2 敲除导致 ROS 水平升高，进而导致精母细胞中的 DNA 损伤，从而引发自噬和凋亡增加，最终导致精子数量显著减少。在体外孵育 QRICH2 的 N 端纯化蛋白在细胞和精子水平上表现出强大的抗氧化活性，从而提高精子的活力和运动能力。因此，QRICH2 通过增强抗氧化能力来保护精母细胞免受过量 ROS 诱导的损伤，从而促进精子的存活和提高运动能力。此外，QRICH2 的 N 端纯化蛋白有望作为一种添加剂，在保存和冷冻保存期间保护精子。
