Conserved Transcriptome Features Define Prepubertal Primate Spermatogonial Stem Cells as A_dark Spermatogonia and...

Area of Science:

• Reproductive Biology
• Stem Cell Biology
• Genomics

Background:

• Antineoplastic treatments can cause male infertility by damaging spermatogonial stem cells (SSCs).
• SSC transplantation is a potential fertility restoration method, but identifying prepubertal SSCs is challenging due to a lack of specific biomarkers.
• Current research highlights the need for better understanding of primate SSCs for therapeutic applications.

Purpose of the Study:

• To identify exclusive biomarkers for prepubertal spermatogonial stem cells (SSCs) in primates.
• To compare primate SSCs with mouse SSCs to understand cross-species differences.
• To resolve the molecular identity of human SSCs and their relationship with histological classifications.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) of testis cells from immature baboons and macaques.
• Comparison of primate scRNA-seq data with published human and mouse prepubertal testis cell data.
• Correlation of molecular definitions of spermatogonia with histological classifications (A_dark/A_pale).

Main Results:

• Primate spermatogonia showed less heterogeneity compared to human cells.
• Cross-species analysis identified primate SSC analogs but revealed significant differences from mouse SSCs.
• Primate SSCs are characterized by genes involved in actin cytoskeleton regulation and cell adhesion, explaining challenges in in vitro culture.
• Human SSCs and progenitor spermatogonia molecularly map to A_dark spermatogonia, while A_pale cells are differentiation-biased.

Conclusions:

• This study resolves the molecular identity of prepubertal human SSCs.
• Novel pathways for SSC selection and in vitro propagation were identified.
• The human SSC pool is confirmed to reside within A_dark spermatogonia, providing a basis for improved fertility preservation strategies.