GLI3 resides at the intersection of hedgehog and androgen action to promote male sex differentiation.

Urogenital tract abnormalities are among the most common congenital defects in humans. Male urogenital development requires Hedgehog-GLI signaling and testicular hormones, but how these pathways interact is unclear. We found that Gli3XtJ mutant mice exhibit cryptorchidism and hypospadias due to local effects of GLI3 loss and systemic effects of testicular hormone deficiency. Fetal Leydig cells, the sole source of these hormones in developing testis, were reduced in numbers in Gli3XtJ testes, and their functional identity diminished over time. Androgen supplementation partially rescued testicular descent but not hypospadias in Gli3XtJ mutants, decoupling local effects of GLI3 loss from systemic effects of androgen insufficiency. Reintroduction of GLI3 activator (GLI3A) into Gli3XtJ testes restored expression of Hedgehog pathway and steroidogenic genes. Together, our results show a novel function for the activated form of GLI3 that translates Hedgehog signals to reinforce fetal Leydig cell identity and stimulate timely INSL3 and testosterone synthesis in the developing testis. In turn, exquisite timing and concentrations of testosterone are required to work alongside local GLI3 activity to control development of a functionally integrated male urogenital tract.

Effect of 1,25-dihydroxyvitamin d on testicular morphology and gene expression in experimental cryptorchid mouse: testis specific cDNA microarray analysis and potential implication in male infertility.

PURPOSE: We evaluated the morphological effect and alterations in gene expression caused by 1,25-dihydroxyvitamin D treatment in the mouse testis undergoing experimental cryptorchidism and subsequent orchiopexy. MATERIALS AND METHODS: The mean modified Johnsen score and testicular weight were estimated after 4 weeks of treatment with a 1,25-dihydroxyvitamin D prodrug. We examined sites of vitamin D receptor and mRNA expression, and 1,25-dihydroxyvitamin D analogue accumulation in the mouse testis. Also, we compared alterations in gene expression in the cryptorchid mouse testis with or without 1,25-dihydroxyvitamin D administration by testis specific cDNA microarray. We confirmed protein synthesis of a candidate among up-regulated genes in primary cultures of Sertoli's cells by Western blotting. RESULTS: Mean +/- SEM Johnsen score and testicular weight were increased by 1,25-dihydroxyvitamin D treatment but not significantly (6.12 +/- 0.33 vs 5.27 +/- 0.4 and 49.3 +/- 3.8 mg vs 42.6 +/- 5.5, p = 0.13 and 0.065, respectively). Vitamin D receptor and its mRNA were positive in Sertoli's cells. The 1,25-dihydroxyvitamin D analogue accumulated mainly in Sertoli's cells. Of 2,483 testis specific genes 19 showed up-regulation by 1,25-dihydroxyvitamin D treatment. Of these genes the regulator of cellular cholesterol homeostasis Abca1 was expressed mainly in Sertoli's cells and influenced male fertility. In primary cultures of Sertoli's cells the synthesis of Abca1 protein was increased by 1,25-dihydroxyvitamin D treatment but not by follicle-stimulating hormone or testosterone treatment. CONCLUSIONS: We noted that 1,25-dihydroxyvitamin D contributes to spermatogenesis by up-regulating certain specific genes in Sertoli's cells. Testis specific cDNA microarray analysis and vitamin D supplementation may have implications for managing male infertility.