JMJD3 Deficiency Alters H3K27me3 Landscapes and Adhesion-Related Transcriptional Programs in Aged Spermatogonia

Spermatogonial stem cells (SSCs) sustain spermatogenesis throughout life by generating differentiating spermatogonia, spermatocytes, and spermatozoa. During this process, male germ cells are interconnected by intercellular bridges (ICBs). Although ICB fragmentation has been implicated in the replenishment of the SSC pool, the molecular mechanisms underlying this process remain poorly understood. Our previous study demonstrated that JMJD3 deficiency promotes spermatogonial fragmentation and preserves spermatogenesis during ageing. To investigate the molecular basis underlying these phenotypes, we performed H3K27me3 ChIP-seq using a spermatogonia-enriched CD9-positive cell fraction together with RNA-seq of SSC-enriched spermatogonial populations from JMJD3-deficient mice. Cross-dataset comparison revealed extensive alterations in H3K27me3 landscapes accompanied by age- and JMJD3-dependent transcriptional changes. RNA-seq demonstrated downregulation of multiple signaling pathways, including NF-κB and TNF signaling, together with dysregulation of extracellular matrix (ECM)- and cell adhesion-related genes in JMJD3-deficient spermatogonia. Consistent with these transcriptional changes, JMJD3-deficient spermatogonia exhibited excessive ECM accumulation and altered expression of adhesion-associated genes in vivo. Although several mesenchymal-associated genes were upregulated, canonical cadherin switching was not observed, indicating the presence of partial epithelial-mesenchymal transition (EMT)-like transcriptional features rather than a complete EMT program. Cross-dataset comparison further identified Ptk2b as a candidate gene associated with JMJD3-dependent H3K27me3 changes. These findings suggest that JMJD3 deficiency is associated with extensive epigenomic remodeling and adhesion-related transcriptional alterations in aged spermatogonia and provide candidate molecular pathways that may contribute to the maintenance of spermatogenesis during ageing.