Spatiotemporal atlas of primate testicular aging implicates anchoring junction collapse and GLDN downregulation in spermatogenesis decline

Abstract Age-related decline in male fertility is closely associated with testicular aging, yet the spatial mechanisms underlying spermatogenic dysfunction remain poorly understood. Here, we integrated single-cell RNA sequencing and spatial transcriptomics to characterize cellular, molecular, and spatial alterations in adult and aged cynomolgus monkey testes. Aged testes exhibited impaired spermatogenic programs, reduced spermatocyte and Sertoli cell abundance and weakened spatial interactions between these populations. Cell–cell communication and spatial analyses further revealed attenuation of adhesion-associated signaling and deterioration of germ cell–Sertoli cell anchoring junctions, accompanied by disruption of the nectin-3/afadin–F-actin cytoskeletal module. Spatial co-expression analysis identified GLDN as an age-sensitive adhesion-associated factor that was markedly reduced in aged testes. Importantly, loss-of-function analysis in Gldn -knockout mice showed disrupted seminiferous epithelial organization and reduced CADM1 expression, supporting a functional role for GLDN in maintaining testicular epithelial and adhesion-related integrity. Together, these findings provide a spatially resolved framework for primate testicular aging and highlight deterioration of germ cell–Sertoli cell adhesion as an important feature of age-associated spermatogenic decline.