Integrated single-nucleus transcriptomic and chromatin accessibility analysis reveals key molecular basis of human testicular aging

The human testis, a crucial organ in male reproduction, is mainly responsible for spermatogenesis and androgen production. As men age, testicular function declines, yet the underlying molecular mechanisms are still not well understood. To elucidate the mechanisms of human testicular aging, we performed an integrated analysis of single-nucleus transcriptomes and chromatin accessibility (snRNA-seq and snATAC-seq) on pathologically confirmed non-tumor testicular tissues from young and aged individuals. Our integrated multi-omic analysis reveals significant age-induced alterations in the testis transcriptome, particularly affecting genes linked to spermatogenesis. Significant age-related changes were also observed in Sertoli and Leydig cells, with Sertoli cells exhibiting increased sensitivity to environmental influences as age. Furthermore, the expression of Wntless (WLS), a Wnt transporter, was substantially upregulated in Sertoli cells of aged testes, which was correlated with cellular senescence and the disruption of tight junctions. Overexpression of WLS in Sertoli cells significantly accelerated senescence in vitro, implying a potential role for WLS in testicular aging. Our study provides a detailed multi-omic map of the transcriptomic and chromatin accessibility changes in the human testis during aging, offering insights into the cellular and molecular mechanisms behind these changes, and identifying potential therapeutic targets for interventions against age-related declines in male reproductive health.