Follicle-Stimulating Hormone-Induced Aromatase in Immature Rat Sertoli Cells Requires an Active Phosphatidylinositol 3-Kinase Pathway and Is Inhibited via the Mitogen-Activated Protein Kinase Signaling Pathway

Abstract

Postnatal development and function of testicular Sertoli cells are regulated primarily by FSH. During this early period of development, estrogens play a role in proliferation of somatic cells, which contributes significantly to testicular development. Growth factors like epidermal growth factor (EGF) are produced in the testis and play a role in regulation of estradiol production and male fertility. Although these divergent factors modulate gonadal function, little is known about their mechanism of action in Sertoli cells. The present study investigates the intracellular events that take place down-stream of FSH and EGF receptors in Sertoli cells isolated from immature (10-d-old) rats, and examines which intracellular signals may be involved in their effects on aromatase activity and estradiol production in immature rat Sertoli cells. Primary cultures of rat Sertoli cells were treated with FSH in combination with EGF and signaling pathway-specific inhibitors. Levels of estradiol production, aromatase mRNA (Cyp19a1), and aromatase protein (CYP19A1) were determined. Western blot analysis was performed to determine the effects of FSH and EGF on levels of activated (phosphorylated) AKT1 and p42 ERK2 and p44 ERK1, also named MAPK1 and MAPK3, respectively. The stimulatory actions of FSH on aromatase mRNA, aromatase protein, and estradiol production were blocked by inhibition of the phosphatidylinositol 3-kinase/AKT1 signaling pathway. In contrast, inhibition of ERK signaling augmented the stimulatory effects of FSH on estradiol production, aromatase mRNA, and protein levels. Furthermore, EGF inhibited the expression of aromatase mRNA and protein in response to FSH, and these inhibitory effects of EGF were critically dependent on the activation of the ERK signaling pathway. We conclude that an active phosphatidylinositol 3-kinase /AKT signaling pathway is required for the stimulatory actions of FSH, whereas an active ERK/MAPK pathway inhibits estradiol production and aromatase expression in immature Sertoli cells.

JunD Is Required for Proliferation of Prostate Cancer Cells and Plays a Role in Transforming Growth Factor-β (TGF-β)-induced Inhibition of Cell Proliferation

“…For DU145, PC3, and LNCaP cells, their culture media were changed to 1% FBS after 24 h, whereas for RWPE1 cells, culture medium was changed to EpiLife medium. The cells were then treated with TGF-␤1 (5 ng/ml) for 0, 1, and 8 h. Total RNA was isolated from the cells using TRIzol (Life Technologies) as described previously (88). 2 g of total RNA were reverse-transcribed, and the resulting cDNAs were diluted 4-fold with RNase-free water.…”

Marijuana, phytocannabinoids, the endocannabinoid system, and male fertility

“…It activates adenylate cyclase which, in turn, causes PKA activation via cAMP, thereby causing increased expression of FAAH [63]. The other pathway triggered by FSH is by the activation of PI-3 which stimulates the expression of aromatases (at a transcriptional level) and thus increase estrogen levels in the cell (see Fig.…”

Aromatase expression in the ovary: Hormonal and molecular regulation

“…Since FSH stimulates cAMP production very rapidly, it has been proposed that an increase in the expression of the regulatory and catalytic units of protein kinase A (PKA) or proteins synthesized as a consequence of PKA activation may be required for aromatase induction [32]. Interestingly, FSH rapidly stimulates aromatase in the Sertoli cells of immature rats [64]. In these cells, the stimulatory action of FSH on aromatase expression also depends on the cAMP/PKA and PI3K/ AKT1 pathways [64].…”

“…Interestingly, FSH rapidly stimulates aromatase in the Sertoli cells of immature rats [64]. In these cells, the stimulatory action of FSH on aromatase expression also depends on the cAMP/PKA and PI3K/ AKT1 pathways [64]. Studies aimed to compare the regulation of the aromatase gene in Sertoli and granulosa cells could provide information on the mechanisms by which the expression of this gene is delayed in granulosa cells.…”