Regulation of Energy and Cholesterol Metabolisms During Fetal Leydig Cell Differentiation by DHH, PDGF, and Ad4BP/SF-1

Fetal Leydig cells (FLCs) are crucial for androgen production during fetal development. Their differentiation from progenitor cells is regulated by various factors, including desert hedgehog (DHH), platelet-derived growth factor (PDGF), and the transcription factor Ad4BP/SF-1 (NR5A1). Our previous research revealed significant upregulation of energy metabolism genes during FLC differentiation; however, the underlying regulatory mechanisms remain unresolved. The present study aimed to elucidate these mechanisms. Through transcriptome analysis, CUT&RUN sequencing (CUT&RUN-seq), and metabolic activity assays, we demonstrated that DHH and PDGF rapidly activate energy metabolism in interstitial cells, involving the FLC progenitor cells, without altering gene expression. In contrast, Ad4BP/SF-1 sustains high metabolic activity in differentiated FLCs through transcriptional activation. Reporter gene assays revealed that GLI1/GLI2, activated by DHH signaling, upregulates Ad4BP/SF-1 gene expression, suggesting a key role for DHH in FLC differentiation. Additionally, DHH signaling activates cholesterogenic gene expression possibly through upregulation of the Srebf2 gene. These findings uncover two distinct mechanisms of metabolism regulation by DHH in progenitor cells: a gene regulation-independent control of energy metabolism and a gene regulation-dependent modulation of cholesterogenesis. Furthermore, our results underscore the pivotal role of Ad4BP/SF-1 in maintaining metabolic activity in FLCs. This study provides novel insights into the regulation of energy and cholesterol metabolisms during FLC differentiation, contributing to a deeper understanding of reproductive system development.