Mutant NR5A1/SF-1 in patients with disorders of sex development shows defective activation of the SOX9 TESCO enhancer.

Nuclear receptor subfamily 5 group A member 1/Steroidogenic factor 1 (NR5A1; SF-1; Ad4BP) mutations cause 46,XY disorders of sex development (DSD), with phenotypes ranging from developmentally mild (e.g., hypospadias) to severe (e.g., complete gonadal dysgenesis). The molecular mechanism underlying this spectrum is unclear. During sex determination, SF-1 regulates SOX9 (SRY [sex determining region Y]-box 9) expression. We hypothesized that SF-1 mutations in 46,XY DSD patients affect SOX9 expression via the Testis-specific Enhancer of Sox9 core element, TESCO. Our objective was to assess the ability of 20 SF-1 mutants found in 46,XY DSD patients to activate TESCO. Patient DNA was sequenced for SF-1 mutations and mutant SF-1 proteins were examined for transcriptional activity, protein expression, sub-cellular localization and in silico structural defects. Fifteen of the 20 mutants showed reduced SF-1 activation on TESCO, 11 with atypical sub-cellular localization. Fourteen SF-1 mutants were predicted in silico to alter DNA, ligand or cofactor interactions. Our study may implicate aberrant SF-1-mediated transcriptional regulation of SOX9 in 46,XY DSDs.

Hematopoietic prostaglandin D synthase (H-Pgds) is expressed in the early embryonic gonad and participates to the initial nuclear translocation of the SOX9 protein.

In mammals, the Prostaglandin D(2) (PGD(2) ) signaling pathway is involved in male gonadal development, regulating Sox9 gene expression and SOX9 protein subcellular localization through lipocalin prostaglandin D synthase (L-Pgds) activity. Nevertheless, because L-Pgds is downstream of Sox9, its expression cannot explain the initial nuclear translocation of the SOX9 protein. Here, we show that another source of PGD(2) , hematopoietic-Pgds (H-Pgds) enzyme is expressed in somatic and germ cells of the embryonic gonad of both sexes, as early as embryonic day (E) 10.5, before the onset of L-Pgds expression. Inhibition of H-Pgds activity by the specific HQL-79 inhibitor leads to impaired nuclear translocation of SOX9 protein in E11.5 Sertoli cells. Furthermore, analysis of H-Pgds(-/-) male embryonic gonads confirms abnormal subcellular localization of SOX9 protein at the E11.5 early stage of mouse testicular differentiation suggesting a role for H-Pgds-produced PGD(2) in the initial nuclear translocation of SOX9.

[Prostaglandin D2: new roles in the embryonic and pathological gonad]. / La prostaglandine D2: nouveaux rôles dans la gonade embryonnaire et pathologique.

Prostaglandin D2 (PGD2) belongs to the superfamily of ubiquitous signalling molecules, the prostaglandins ; these bind to specific G-coupled transmembrane receptors, inducing various transduction pathways. Prostaglandins PGE2 and PGF2alpha have several identified functions during ovulation, fecondation and embryo implantation. However, the roles of PGD2 within the male or female reproductive organs are still largely unknown, even though the PGD2-producing enzyme, prostaglandin D synthase (PGDS), is detected in these organs. In this study, we summarize recent data highlighting new functions of PGD2 in the onset of testicular embryogenesis and in the growth inhibition of ovarian cancer cells. In both cases, PGD2 acts by activating the function of the Sertoli cell differentiating factor SOX9.

The PGD2 pathway, independently of FGF9, amplifies SOX9 activity in Sertoli cells during male sexual differentiation.

Activation by the Y-encoded testis determining factor SRY and maintenance of expression of the Sox9 gene encoding the central transcription factor of Sertoli cell differentiation are key events in the mammalian sexual differentiation program. In the mouse XY gonad, SOX9 upregulates Fgf9, which initiates a Sox9/Fgf9 feedforward loop, and Sox9 expression is stimulated by the prostaglandin D2 (PGD2) producing lipocalin prostaglandin D synthase (L-PGDS, or PTDGS) enzyme, which accelerates commitment to the male pathway. In an attempt to decipher the genetic relationships between Sox9 and the L-Pgds/PGD2 pathway during mouse testicular organogenesis, we found that ablation of Sox9 at the onset or during the time window of expression in embryonic Sertoli cells abolished L-Pgds transcription. By contrast, L-Pgds(-/-) XY embryonic gonads displayed a reduced level of Sox9 transcript and aberrant SOX9 protein subcellular localization. In this study, we demonstrated genetically that the L-Pgds/PGD2 pathway acts as a second amplification loop of Sox9 expression. Moreover, examination of Fgf9(-/-) and L-Pgds(-/-) XY embryonic gonads demonstrated that the two Sox9 gene activity amplifying pathways work independently. These data suggest that, once activated and maintained by SOX9, production of testicular L-PGDS leads to the accumulation of PGD2, which in turn activates Sox9 transcription and nuclear translocation of SOX9. This mechanism participates together with FGF9 as an amplification system of Sox9 gene expression and activity during mammalian testicular organogenesis.