Deciphering the regulatory networks of human male germline development from embryo to adulthood.

Male germline development is crucial for the proper establishment of spermatogonial stem cell pool and life-long production of spermatozoa, but the full-term developmental profiling of human male germline is not fully understood. Here, by integrating 92,488 human testicular cells spanning from six-week-old embryos to old men, we constructed a comprehensive human male germ cell atlas. Further analysis found that the precursor of undifferentiated spermatogonia underwent regulatory network reconfiguration starting from week 7 post-fertilization, accompanied by WNT6-FZD3/LRP6-JUN/MYC signaling axis. And JUN and MYC were revealed to be candidate core transcription factors that might inhibit spermatogonia differentiation. In addition, the activation of ANGPTL signaling played a role in the maintenance of human spermatogonial stem cells. Finally, by interrogating the scRNA-seq datasets from idiopathic non-obstructive azoospermia (iNOA) patients, we identified several iNOA-dysregulated genes such as CAPN3, FTMT, IZUMO2 and LACE1, which were significantly down-regulated in round spermatids of iNOA patients. Collectively, our work established an atlas of human male germ cell development, revealing the factors that might regulate male germline development and providing iNOA-dysregulated genes for future clinical diagnosis.