The Role of Foxo3 in Leydig Cells

Abstract

PurposeFoxo3 in female reproduction has been reported to regulate proliferation of granulose cells that form follicles. There are no reports so far that discuss on the role of Foxo3 in males. This study was designed to outline the role of Foxo3 in the testes.Materials and MethodsTestes from mice at birth to postpartum week (PPW) 5 were isolated and examined for the expression of Foxo3 using immunostaining. To elucidate role of Foxo3 in Leydig cells, R2C cells were treated with luteinizing hormone (LH) and the phosphorylation of Foxo3. Testosterone and steroidogenic acute regulatory (StAR) protein levels were measured after constitutive active [triple mutant (TM)] human FOXO3 adenovirus was transduced and StAR promoter assay was performed.ResultsFoxo3 expression in the testicles started from birth and lasted until PPW 3. After PPW 3, most Foxo3 expression occurred in the nuclei of Leydig cells; however, at PPW 5, Foxo3 was expressed in both the nucleus and cytoplasm. When R2C cells were treated with luteinizing hormone, Foxo3 phosphorylation levels by AKT increased. After blocking the PI3K pathway, LH-induced phosphorylated Foxo3 levels decreased, indicating that LH signaling regulates Foxo3 localization. When active FOXO3-TM adenovirus was introduced into a Leydig tumor cell line, the concentrations of testosterone and StAR protein decreased. When FOXO3 and a StAR promoter vector were co-transfected into HEK293 cells for a reporter assay, FOXO3 inhibited the StAR promoter.ConclusionFOXO3 affects testosterone synthesis by inhibiting the formation of StAR protein. LH hormone, meanwhile, influences Foxo3 localization, mediating its function.

Poorly-Controlled Type 1 Diabetes Mellitus Impairs LH-LHCGR Signaling in the Ovaries and Decreases Female Fertility in Mice

“…1E, left; control, middle; AKITA, and right; STZ-injected). Immunofluorescence showed uneven expression of AMH in antral follicles in the ovaries of AKITA mice, while it was uniformly expressed in granulosa cells of growing follicles (primary, secondary, and multilayered secondary follicles) 16. Furthermore, the expression of ER, a granulosa cell marker, was barely detectable in the granulosa cells of antral follicles from AKITA and STZ-injected mice, while high expression levels of Ki-67 were detected in proliferating granulosa cells in all three groups (Fig.…”

“…1). 16 Three weeks after the blood glucose check, the body weights of control, AKITA, and STZ-injected mice were measured. A total of 150 mice [wild-type C57BL/6J (n=50), AKITA (n=50), and STZ-injected mice (n=50)] were used in this study.…”

FOXO3 Is Expressed in Ovarian Tissues and Acts as an Apoptosis Initiator in Granulosa Cells of Chickens

“…Overexpression of FOXO3 in mouse nerve cells significantly promotes their apoptosis [33]. Likewise, overexpressed FOXO3 regulates apoptosis in testicular mesenchymal cells through BCL2L11 activity [34]. Studies have shown that, in follicle granulosa cells, upregulation of FOXO3 can accelerate follicular atresia in pigs, indicating that the FOXO3 protein has a proapoptotic effect on mammalian granulosa cells [35].…”

Multiple roles of FOXJ3 in spermatogenesis: A lesson from Foxj3 conditional knockout mouse models

“…Several FOX transcription factors are believed to regulate spermatogenesis in mice: FOXO1, which is expressed in gonocytes and undifferentiated spermatogonial cells, plays a crucial role in the gonocyte‐to‐SSC transition, self‐renewal, and differentiation of SSCs (Goertz et al, ). FOXO3 affects testosterone synthesis within testes by inhibiting the formation of Steroidogenic acute regulatory protein (Choi et al, ). FOXJ2 was recently proposed to control meiosis during spermatogenesis, as loss of FOXJ2 in the male germ line leads to meiotic arrest and complete infertility (Miao et al, ).…”