Transcriptomic analyses of the testicular interstitial cells in murine neonates

Previous studies have established that fetal Leydig cells (FLCs) and adult Leydig cells (ALCs) show distinct functional characteristics. However, the lineage relationship between FLCs and ALCs has not been clarified yet. Here we reveal that a subset of FLCs dedifferentiate at fetal stages to give rise to ALCs at the pubertal stage. Moreover, the dedifferentiated cells contribute to the peritubular myoid cells and vascular pericyte populations in the neonatal testis, and these non-steroidogenic cells serve as potential ALC stem cells. We generated FLC lineage-specific Nr5a1 (Ad4BP/SF-1) gene disrupted mice and mice lacking the fetal Leydig enhancer (FLE) of the Nr5a1 gene. Phenotypes of these mice support the conclusion that most of the ALCs arise from dedifferentiated FLCs, and that the FLE of Nr5a1 gene is essential for both initial FLC differentiation and pubertal ALC redifferentiation. Cells were dispersed from mFLE-Cre;CAG-CAT-EGFP mouse testis at postnatal day 10, and EGFP(weak)/Laminin(negative) population and EGFP(positive)/Laminin(positive) pouplations were collected by cell sorting. Duplicated samples in each population were analyzed by RNA-sequence.