Wt1 directs the lineage specification of sertoli and granulosa cells by repressing Sf1 expression

Abstract

Supporting cells (Sertoli and granulosa) and steroidogenic cells (Leydig and theca-interstitium) are two major somatic cell types in mammalian gonads, but the mechanisms that control their differentiation during gonad development remain elusive. In this study, we found that deletion of Wt1 in the ovary after sex determination caused ectopic development of steroidogenic cells at the embryonic stage. Furthermore, differentiation of both Sertoli and granulosa cells was blocked when Wt1 was deleted before sex determination and most genital ridge somatic cells differentiated into steroidogenic cells in both male and female gonads. Further studies revealed that WT1 repressed Sf1 expression by directly binding to the Sf1 promoter region, and the repressive function was completely abolished when WT1 binding sites were mutated. This study demonstrates that Wt1 is required for the lineage specification of both Sertoli and granulosa cells by repressing Sf1 expression. Without Wt1, the expression of Sf1 was upregulated and the somatic cells differentiated into steroidogenic cells instead of supporting cells. Our study uncovers a novel mechanism of somatic cell differentiation during gonad development.

Ex vivo cultures combined with vivo-morpholino induced gene knockdown provide a system to assess the role of WT1 and GATA4 during gonad differentiation

“…Down-regulation of Dhh transcripts in Wt1 vivo -morpholino treated XY gonadal explants (Fig 6A) is in line with a previous report of reduced Dhh expression in Wt1 -deficient testes of adult mice [39]. Furthermore, our findings corroborate a most recent study illustrating decreased Dhh mRNA levels in Wt1 -deficient testes at E13.5 [61]. By demonstrating that WT1 knockdown also decreased Gli1 , Gli2 , Ptch1 and Smo transcripts in embryonic XY gonads (Fig 6A), our findings suggest that WT1 activates the HH pathway at multiple stages.…”

Evidence that downregulation of Wilms’ tumor 1 (WT1) is involved in cortical stromal cell differentiation into theca cells in adult bovine ovaries

“…In WT1‐deficient XY gonads of mice at E13.5, the downregulation of WT1 increased the levels of mRNA for StAR , CYP11A1 , 3β‐HSD , and CYP17A1 (Chen et al, ); however, in ovaries from 3‐week‐old mice, a WT1 mutation had no effect on the levels of mRNA for CYP11A1 and 3β‐HSD in granulosa cells (Gao et al, ). In our study, the downregulation of WT1 increased the level of mRNA for 3β‐HSD but had no effect on the level of mRNA for StAR , CYP11A1 , or CYP17A1 in adult cortical stromal cells.…”

“…The differences may also be explained by the differences in cell types and stages of development. Previous studies have shown that 3β‐HSD‐positive cells are steroidogenic cells, such as theca‐interstitial cells, and that the 3β‐HSD expression level represents the degree of steroidogenic cell differentiation (Chen et al, ; Honda et al, ; Jeays‐Ward et al, ). In our study, the expression of 3β‐HSD in the cortical stroma was significantly lower than that in the theca layer.…”

“…WT1, which encodes a zinc finger transcription factor, plays important roles at different stages during gonad development in mice (Bandiera et al, ; Chen et al, ). Before sex determination, the deletion of WT1 can affect the differentiation of the supporting cells and can disturb the differentiation of male and female gonads; after sex determination, WT1 downregulation can lead to the abnormal development of steroidogenic cells in mouse testes and ovaries (Chen et al, ). In adults, WT1 dictates the fate of leydig cells and regulates the differentiation of sertoli cells and granulosa cells in mouse (Gao et al, , ; Wen et al, ; Zhang et al, ).…”

“…The differentiation of cortical stromal cells was evaluated by the induction of theca cell functional markers, such as androstenedione and progesterone secretion and LH responsiveness (Orisaka et al, ; Parrott & Skinner, ; Young & McNeilly, ). Previous studies have demonstrated that the deletion of WT1 in Sertoli cells induces an increase in the progesterone and 17β‐estradiol levels and inhibits the testosterone level in mouse testes (Chen et al, ; Wen et al, ); however, in fetal mouse ovaries, the deletion of WT1 can induce an increase in testosterone (Chen et al, ). Furthermore, the deletion of WT1 may increase (Gao et al, ; Zhang et al, ), suppress (Chen et al, ), or exert no effect on (Wang et al, ) LHR expression in different tissues in mice and human.…”