Transcription factor E4F1 dictates spermatogonial stem cell fate decisions by regulating mitochondrial functions and cell cycle progression

Abstract

Background Spermatogonial stem cells (SSCs) provide a foundation for robust and continual spermatogenesis in mammals. SSCs self-renew to maintain a functional stem cell pool and differentiate to supply committed progenitors. Metabolism acts as a crucial determinant of stem cell fates; however, factors linking metabolic programs to SSC development and maintenance are poorly understood. Results We analyzed the chromatin accessibility of undifferentiated spermatogonia at the single-cell level and identified 37 positive TF regulators that may have potential roles in dictating SSC fates. The transcription factor E4F1 is expressed in spermatogonia, and its conditional deletion in mouse germ cells results in progressive loss of the entire undifferentiated spermatogonial pool. Single-cell RNA-seq analysis of control and E4f1-deficient spermatogonia revealed that E4F1 acts as a key regulator of mitochondrial function. E4F1 binds to promotors of genes that encode components of the mitochondrial respiratory chain, including Ndufs5, Cox7a2, Cox6c, and Dnajc19. Loss of E4f1 function caused abnormal mitochondrial morphology and defects in fatty acid metabolism; as a result, undifferentiated spermatogonia were gradually lost due to cell cycle arrest and elevated apoptosis. Deletion of p53 in E4f1-deficient germ cells only temporarily prevented spermatogonial loss but did not rescue the defects in SSC maintenance. Conclusions Emerging evidence indicates that metabolic signals dictate stem cell fate decisions. In this study, we identified a list of transcription regulators that have potential roles in the fate transitions of undifferentiated spermatogonia in mice. Functional experiments demonstrated that the E4F1-mediated transcription program is a crucial regulator of metabolism and SSC fate decisions in mammals. Graphical Abstract

Elucidating the Role of OXPHOS Variants in Asthenozoospermia: Insights from Whole Genome Sequencing and an In Silico Analysis

“…Lie et al ( 2022) [33] reported also that reduced COX6C expression led to impaired COX enzyme activity, affecting mitochondrial ATP production and thus sperm motility in buffalo. Moreover, oxidative phosphorylation was found to be enriched in all undifferentiated spermatogonia subtypes studied, with significant differences in the relative abundances of Ndufv1 and Cox6c transcripts between control and E4f1-depleted spermatogonia, the latter condition leading to a progressive loss of undifferentiated spermatogonial cells [34]. Other studies highlighted the differential expression of COX6C, NDUFA5, NDUFS7, and NDUFV2 between progenitor and differentiating spermatogonia, too [35].…”

An overview of novel transcription factors involved in spermatogonial stem cells

“…An Overview of Novel Transcription Factors Involved in Spermatogonial Stem Cells DOI: http://dx.doi.org/10.5772/intechopen.1004178 induced by loss of E4F1 activity. P53 deletion in E4F1-deficient germ cells did not correct the abnormalities in SSC maintenance; rather, it merely momentarily stopped spermatogonial loss [35].…”

“…Yan et al examined undifferentiated spermatogonia's chromatin accessibility at the single-cell level, and they discovered 37 positive TF regulators that could play a part in determining the fates of SSCs [35]. The whole undifferentiated spermatogonial pool gradually disappears when the transcription factor E4F1, which is expressed in spermatogonia, is conditionally deleted in mouse germ cells.…”

Elevated Id2 expression causes defective meiosis and spermatogenesis in mice

“…Mice were treated with EdU (RIBOBIO, China) at a dosage of 50 mg/kg body weight via intraperitoneal injections 43 . Two hours after EdU injections, testes were collected and fixed in 4% PFA.…”