Harrer Aileen, Ghatpande Niraj, Grimaldini Tiziana, Fietz Daniela, Kumar Vishnu, Pleuger Christiane, Fijak Monika, Föppl Dankward T, Rynio Lennart P, Schuppe Hans-Christian, Pilatz Adrian, Bartkuhn Marek, Procida-Kowalski Tara, Guttmann-Raviv Noga, Bhushan Sudhanshu, Meyron-Holtz Esther G, Meinhardt Andreas
Institute of Anatomy and Cell Biology, Unit of Reproductive Biology, Justus-Liebig-University of Giessen, Giessen, Germany; Hessian Centre of Reproductive Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, Haifa, Israel.
J Biol Chem. 2025 Jan;301(1):108067. doi: 10.1016/j.jbc.2024.108067. Epub 2024 Dec 10.
Imbalances in testicular iron levels are linked to compromised sperm production and male infertility. Iron regulatory proteins (IRP) 1 and 2 play crucial roles in cellular iron regulation. We investigated the role of IRP1 on spermatogenesis using Irp1-deficient mice (Irp1). Histological analysis of the testis of Irp1 mice revealed hypospermatogenesis with a significant reduction in the number of elongated spermatids and daily sperm production compared to wild-type (WT) mice. Flow cytometry of germ cells from WT and Irp1 mice showed reduction in spermatocytes and round and elongated spermatids in Irp1 mice, which was confirmed by histological and immunofluorescence quantification. Finally, stage VIII of spermatogenesis, crucial for spermatid maturation, was less frequent in Irp1 testicular cross-sections. Hypospermatogenesis worsened with age despite unchanged intratesticular iron levels. Mechanistically, this was due to increased oxidative stress indicated by elevated 8-Oxoguanine (8-OxoG) levels, a DNA lesion resulting from reactive oxygen species (ROS). Furthermore, bulk RNA-seq data indicated compromised DNA damage repair and cell cycle processes, including mitosis and meiosis in Irp1 mice, which may explain hypospermatogenesis. Our results suggest that IRP1 deletion leads to hypospermatogenesis due to impaired cell cycle progression, decreased DNA damage repair capacity, and oxidative damage. Altogether, this study uncovers a role for IRP1, independent of traditional mechanisms of iron regulation.
睾丸铁水平失衡与精子生成受损和男性不育有关。铁调节蛋白（IRP）1和2在细胞铁调节中起关键作用。我们使用Irp1基因敲除小鼠（Irp1）研究了IRP1在精子发生中的作用。与野生型（WT）小鼠相比，对Irp1小鼠睾丸的组织学分析显示精子发生减少，延长型精子细胞数量和每日精子生成量显著降低。对WT和Irp1小鼠生殖细胞的流式细胞术分析显示，Irp1小鼠的精母细胞以及圆形和延长型精子细胞数量减少，这通过组织学和免疫荧光定量得到证实。最后，对精子细胞成熟至关重要的精子发生第八阶段，在Irp1小鼠睾丸横切面中出现的频率较低。尽管睾丸内铁水平不变，但随着年龄增长，精子发生减少的情况会恶化。从机制上讲，这是由于8-氧代鸟嘌呤（8-OxoG）水平升高所表明的氧化应激增加，8-OxoG是一种由活性氧（ROS）导致的DNA损伤。此外，大量RNA测序数据表明Irp1小鼠的DNA损伤修复和细胞周期过程受损，包括有丝分裂和减数分裂，这可能解释了精子发生减少的现象。我们的结果表明，IRP1缺失由于细胞周期进程受损、DNA损伤修复能力降低和氧化损伤而导致精子发生减少。总之，这项研究揭示了IRP1的一种作用，其独立于传统的铁调节机制。
