Fibroblast Growth Factor 9 promotes rat Leydig cell development via H3K4me3 histone modifications

Area of Science:

• Reproductive Biology
• Endocrinology
• Epigenetics

Background:

• Fibroblast Growth Factor 9 (FGF9) is crucial for testis development.
• Histone modifications, particularly H3K4me3, are implicated in steroidogenesis.
• The precise role of FGF9 and histone modifications in Leydig cell (LC) differentiation is not fully understood.

Purpose of the Study:

• To investigate the effect of FGF9 on Leydig cell (LC) differentiation and testosterone synthesis.
• To explore the involvement of histone modifications, specifically H3K4me3, in FGF9-mediated effects.
• To elucidate the regulatory mechanisms of FGF9 in the male reproductive system.

Main Methods:

• Adult male Sprague-Dawley rats were treated with ethane dimethane sulfonate (EDS) to deplete LCs, followed by intratesticular FGF9 injection.
• Quantitative PCR (qPCR) and Western blot were used to assess gene and protein expression related to testosterone synthesis.
• Chromatin immunoprecipitation sequencing (ChIP-seq) identified H3K4me3 binding regions.
• In vitro tubule culture was performed to study FGF9 effects on stem LCs.

Main Results:

• FGF9 treatment increased serum testosterone levels, LC number, and expression of key steroidogenic genes.
• FGF9 significantly elevated H3K4me3 levels and reduced H3K9me3 levels.
• FGF9 promoted H3K4me3 enrichment on the promoter regions of steroidogenic genes (Scarb1, Stard1, Srd5a1).
• In vitro, FGF9 enhanced testosterone production and stem LC proliferation.

Conclusions:

• FGF9 stimulates Leydig cell (LC) proliferation and differentiation.
• FGF9 enhances testosterone production through epigenetic regulation via H3K4me3 modification.
• These findings highlight FGF9 as a key regulator in testicular function and steroidogenesis.