Figure 4.

Future advancements in spermatogenesis built on the single-cell foundation. (A) Spatial reconstitution of single-cell transcriptomes for SSCs may allow prospective localization of SSCs and their cognate niches in the testis. These same data may help identify key growth factor ligand-receptor combinations to facilitate establishment of human SSC culture conditions. Lastly, novel markers of SSCs, progenitors and differentiating spermatogonia could be used to drive transgenic reporters for lineage tracing to confirm assumed cellular relationships. (B) The accumulated knowledge from scRNA-seq of human and mouse testes will enable identification of species-specific and conserved gene expression patterns underlying spermatogenesis. These data will undoubtedly help advance diagnosis and treatment of male infertility as well as new modes for male contraception. Directly emanating from the single-cell data and underlying such translational outcomes would be development of new drugs to solve male infertility and achieve contraception as well as better characterization of cells to be used therapeutically (e.g. SSC transplant) or production and characterization of gametes in a dish.