Sertoli cell (SC) androgen receptor (AR) activity is vital for spermatogenesis. We created a unique gain-of-function transgenic (Tg) mouse model to determine the temporal role of SCAR expression in testicular development. The SC-specific rat Abpa promoter directed human Tg AR [Tg SC-specific AR (TgSCAR)] expression, providing strong premature postnatal AR immunolocalized to SC nuclei. Independent Tg lines revealed that TgSCAR dose dependently reduced postnatal and mature testis size (to 60% normal), whereas androgen-dependent mature seminal vesicle weights and serum testosterone levels remained normal. Total SC numbers were reduced in developing and mature TgSCAR testes, despite normal or higher Fshr mRNA and circulating FSH levels. Postnatal TgSCAR testes exhibited elevated levels of AR-regulated Rhox5 and Spinlw1 transcripts, and precocious SC function was demonstrated by early seminiferous tubular lumen formation and up-regulated expression of crucial SC tight-junction (Cldn11 and Tjp1) and phagocytic (Elmo1) transcripts. Early postnatal Amh expression was elevated but declined to normal levels in peripubertal-pubertal TgSCAR vs. control testes, indicating differential age-related regulation featuring AR-independent Amh down-regulation. TgSCAR induced premature postnatal spermatogenic development, shown by increased levels of meiotic (Dmc1 and Spo11) and postmeiotic (Capza3 and Prm1) germ cell transcripts, elevated meiotic-postmeiotic germ:Sertoli cell ratios, and accelerated spermatid development. Meiotic germ:Sertoli cell ratios were further increased in adult TgSCAR mice, indicating predominant SCAR-mediated control of meiotic development. However, postmeiotic germ:Sertoli cell ratios declined below normal. Our unique TgSCAR paradigm reveals that atypical SC-specific temporal AR expression provides a direct molecular mechanism for induction of precocious testicular development, leading to reduced adult testis size and decreased postmeiotic development.

Diffuse intrinsic pontine glioma (DIPG) is an incurable malignant childhood brain tumor, with no active systemic therapies and a 5-year survival of less than 1%. Polyamines are small organic polycations that are essential for DNA replication, translation and cell proliferation. Ornithine decarboxylase 1 (ODC1), the rate-limiting enzyme in polyamine synthesis, is irreversibly inhibited by difluoromethylornithine (DFMO). Herein we show that polyamine synthesis is upregulated in DIPG, leading to sensitivity to DFMO. DIPG cells compensate for ODC1 inhibition by upregulation of the polyamine transporter SLC3A2. Treatment with the polyamine transporter inhibitor AMXT 1501 reduces uptake of polyamines in DIPG cells, and co-administration of AMXT 1501 and DFMO leads to potent in vitro activity, and significant extension of survival in three aggressive DIPG orthotopic animal models. Collectively, these results demonstrate the potential of dual targeting of polyamine synthesis and uptake as a therapeutic strategy for incurable DIPG.

We determined the functional role of the Sertoli cell glucocorticoid receptor (GR) in vivo using a transgenic Cre-loxP approach to conditionally disrupt GR expression. Sertoli cell GR knockout (SCGRKO) was shown by absent Sertoli cell-specific GR immunolocalization and reduced levels of glucocorticoid-responsive Stc1 and Tsc22d3 mRNA in SCGRKO relative to control testes. Adult SCGRKO testes exhibited distinct morphological changes, including reduced seminiferous tubular lumen formation, decreased total Sertoli cell numbers, and parallel reductions in meiotic spermatocyte and postmeiotic spermatid numbers. Conversely, tubular diameter was increased and testis size was normal in SCGRKO males. Decreased serum FSH and testicular Fshr mRNA levels were consistent with reduced Sertoli cell number. Adult SCGRKO testes also displayed atypical germ cells and interstitial focal accumulations of hypertrophic lipid-laden, immature-like Leydig cells. Circulating LH, and testicular Lhr mRNA, testosterone, dihydrotestosterone, and 3α/3β-diol levels were all reduced in mature SCGRKO mice, whereas serum testosterone and dihydrotestosterone levels remained normal. Moreover, Sertoli cell GR disruption caused differential changes to steroidogenic enzyme transcripts, with down-regulated testicular Cyp11a1 contrasting with up-regulated Hsd17b3 expression. Reduced SCGRKO testicular expression of Hsd11b2, encoding an enzyme for corticosterone inactivation, supports a dynamic coupling between Hsd11b and androgen production. Our novel SCGRKO model has revealed that Sertoli cell-mediated GR actions support normal testicular function. Sertoli cell GR is required to maintain normal testicular Sertoli/germ cell numbers and circulating gonadotropin levels, as well as optimal Leydig cell maturation and steroidogenesis, providing new insight into gluocorticoid-mediated impact on male reproduction.