Protective Role of the EGR1-Nudt16L1 Pathway in Spermatogonial Stem Cells Against Testicular Ischemia-Reperfusion...

Spermatogonial stem cells (SSCs) are essential for maintaining sperm production but are highly susceptible to damage from testicular ischemia-reperfusion (IR) injury, a common consequence of conditions like testicular torsion. This injury leads to oxidative stress, disruption of the blood-testis barrier (BTB), and germ cell death. While the transcription factor EGR1 is known to promote SSC survival in laboratory settings, its protective mechanisms within a living organism remained unclear. This study aimed to identify the downstream targets through which EGR1 confers protection against IR injury. Through bioinformatic analysis, a potential binding site for EGR1 was discovered in the promoter of the Nudt16L1 gene. A series of experiments, including chromatin immunoprecipitation and luciferase reporter assays, confirmed that EGR1 directly binds to this site and activates Nudt16L1 expression. In a mouse model of testicular IR injury, overexpression of EGR1 was found to alleviate tissue damage, improve sperm motility, and preserve the integrity of the BTB. Crucially, when Nudt16L1 was experimentally silenced, the protective benefits of EGR1 were lost. Conversely, overexpressing Nudt16L1 alone was sufficient to mimic EGR1's protective effects, reducing reactive oxygen species and preventing cell death in SSCs subjected to oxygen-glucose deprivation/reperfusion, an in vitro model of IR. In conclusion, this research identifies Nudt16L1 as a critical downstream effector of EGR1. The EGR1-Nudt16L1 signaling axis protects SSCs from IR injury by mitigating oxidative stress, maintaining BTB integrity, and inhibiting apoptosis. These findings highlight this pathway as a promising therapeutic target for preventing infertility resulting from testicular torsion and similar ischemic events.