ESPE Yearbook of Paediatric Endocrinology

Nat Commun. 2025 Apr 29;16(1):3987. doi: 10.1038/s41467-025-59183-6

Brief summary: This study combined single-nucleus multiomics, ChIP-seq and genetic mouse models, Estermann and collagues investigated the role of NR2F2, an orphan nuclear receptor, in shaping the fate of interstitial cells during embryonic testis development in mice. Their findings demonstrate that NR2F2 is crucial for guiding progenitor cells toward steroidogenic Leydig cell lineage rather than other interstitial cell types. Genetic deletion of NR2F2 disrupts Leydig cell differentiation, leading to abnormal Sertoli–Leydig cell balance, impaired androgen production, and disruption in testis architecture. These developmental perturbations provide a mechanistic link between NR2F2 dysfunction and DSD, underscoring its significance in ensuring proper sex differentiation via endocrine pathways.

This study provides important insights into fetal Leydig cell biology by highlighting the often-overlooked role of the interstitial compartment of the embryonic testis, particularly the transcription factor NR2F2 (COUP-TFII). While testicular development research has largely focused on Sertoli and germ cells, this work emphasizes the diversity of non-steroidogenic interstitial cells and their impact on testicular architecture and male sex development.

Fetal Leydig cells emerge from interstitial progenitors around embryonic day 12.5 in mice. Their differentiation is promoted by Desert Hedgehog (DHH) signaling and inhibited by Notch and VEGF pathways. Disruptions in this balance may result in DSD and male reproductive defects. The interstitial space also contains other non-steroidogenic cells marked by genes such as Tcf21, Wnt5a, Arx, Pdgfra, and Nr2f2. These markers contribute to specific lineages, including Leydig and peritubular myoid cells.

Using multi-omics and genetic mouse models, the authors identify fetal Leydig progenitors and demonstrate that NR2F2 is essential for their differentiation from non-steroidogenic interstitial cells. NR2F2 regulates interstitial cell identity and inhibits premature Leydig differentiation by repressing Notch/VEGF signaling and key steroidogenic genes. Loss of Nr2f2 leads to phenotypes resembling human DSD, including gonadal dysgenesis, cryptorchidism, hypospadias, and Leydig cell hypoplasia.

Despite its strengths, the study has limitations. The lack of lineage tracing before E11.5 leaves the earliest origins of Leydig progenitors unclear. Additionally, the mechanism by which NR2F2 is silenced remains unknown, and the effects of NR2F2 loss on androgen output were inferred rather than directly measured. Nonetheless, this study significantly enhances our understanding of testicular development and offers a molecular basis for NR2F2-related human DSDs.