Region-specific transcriptomic responses to CD52 deficiency in the male reproductive tract

Spermatozoa are produced in the testis and acquire motility and fertilizing capacity during post-testicular maturation in the epididymis, a highly region-specific process. How gene loss reshapes region-specific transcriptional programs along the testis–epididymis axis remains poorly defined, particularly in the absence of overt fertility defects. CD52 is expressed in male reproductive tissues, yet whether CD52 loss elicits region-specific transcriptomic alterations along the male reproductive tract remains unclear. In this study, we aimed to systematically characterize spatially resolved transcriptomic changes associated with CD52 deficiency across the testis and epididymal segments. CD52-knockout male mice displayed normal fertility, as assessed by successful mating and offspring production, and showed no obvious histological abnormalities in the testis or epididymis. Multi-region bulk RNA sequencing identified differentially expressed genes in the testis (119), caput epididymis (284), corpus epididymis (577), and cauda epididymis (294). Functional enrichment analyses revealed that pathways related to cytoskeletal organization and motor protein function were predominantly affected in the testis, caput, and cauda. In contrast, pathways associated with cellular homeostasis and ion transport were uniquely enriched in the corpus epididymis. Protein–protein interaction network analysis further identified region-specific hub genes, including Ttn in the testis and cauda, Tcap in the caput epididymis, as well as Spp1 in the corpus epididymis. Comparative analyses between adjacent tissues highlighted pronounced transcriptional heterogeneity along the testis–epididymis axis in response to CD52 deficiency. This study provides a region-resolved transcriptomic characterization of CD52 deficiency across the testis and epididymal segments. Our findings demonstrate that CD52 loss is associated with distinct, spatially organized transcriptional responses along the male reproductive tract, offering insight into region-dependent molecular regulation in the absence of overt reproductive phenotypes.