In Vivo Actions of the Sertoli Cell Glucocorticoid Receptor

Abstract

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.

Glucocorticoids and Reproduction: Traffic Control on the Road to Reproduction

“…Glucocorticoid signaling in the uterus may also be required for the cell-fate decision of stromal cells during decidualization, although the direct gene targets of GR that regulate cell proliferation or apoptosis in the uterus have yet to be determined. Deletion of NR3C1 in the Sertoli cells through the use of anti-Mullerian hormone (AMH) Cre also produced a profound phenotype, where GR was determined to be required for Sertoli cell maintenance [54]. Although male Sertoli cell-specific NR3C1 knockout mice are fertile, the numbers of Sertoli cells and stage-specific spermatocytes/spermatids were significantly reduced.…”

Animal Models of Altered Glucocorticoid Signaling

“…Deletion of GR in sertoli cells (using anti-Mullerian hormone-cre) resulted in decreased sertoli cell number, circulating FSH and secondarily decreased LH and abnormal Leydig cell morphology, but these mice were fertile [ 62 ]. As mentioned above, deletion of GR in noradrenergic cells (using dopamine beta hydroxylase cre) resulted in decreased numbers of adrenal chromaffi n cells in adults.…”

Elevated expression of the Sertoli cell androgen receptor disrupts male fertility

“…Cell apoptosis was determined using an ApopTag Peroxidase In Situ Apoptosis Detection Kit (Chemicon S7100) according to the manufacturer's protocol and treating testis sections with proteinase K for 15 min, followed by 3% H 2O2 treatment for 10 min (12). Testis sections were counterstained with Harris hematoxylin and eosin solution.…”

“…Mouse serum FSH levels were measured by immunofluorometric assay, as described previously (12,15). All samples were measured in duplicate in a single batch.…”