Chia Ling Chung

Fibroblast growth factor 9 stimulates steroidogenesis in postnatal Leydig cells.

Fibroblast growth factor 9 (FGF9) is a potent mitogen and survival factor required for morphogenesis during embryonic development and numerous biological functions at adulthood. The reproductive phenotype of mice lacking Fgf9 gene exhibits male to female sexual reversal, suggesting a crucial role of Fgf9 in male sex determination. Our previous study showed that polymorphic microsatellite of FGF9 genes is associated with 46XY female with ambiguous genitalia, implying that the aberrant expression of FGF9 might affect androgen secretion. In this study, we aimed to investigate the effect of FGF9 on testosterone production in mouse Leydig cell and to study the signalling pathways by which FGF9 modulate steroidogenesis. Our results show that mRNAs of Fgf9 and Fgfr isoforms (Fgfr2IIIc, Fgfr3 and Fgfr4) were all expressed in mouse Leydig cells. FGF9 significantly stimulates mouse Leydig cell testosterone production in a dose- and time-dependent manner. Ras-MAPK, PI3K and PKA signalling pathways are involved in the FGF9-induced steroidogenesis. These results provide supportive evidence linking the aberrant expression of FGF9 to human gonadal dysgenesis and suggest a role of FGF9 in postnatal testicular development.

Protein tyrosine phosphatase non-receptor type 14 is a novel sperm-motility biomarker

PurposeTo understand the molecular basis of sperm-motility and to identify related novel motility biomarkers.MethodsTwo-dimensional electrophoresis (2DE) followed by Reverse-phase-nano-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (RP-nano-HPLC-ESI-MS/MS) were applied to establish the human sperm proteome. Then the sperm proteome of moderate-motile human sperm fraction and that of good-motile human sperm fraction from pooled spermatozoa of forty normozoospermic donors (Group 1 subjects) were compared to identify the dysregulated proteins. Among these down-regulated proteins, Protein tyrosine phosphatase non-receptor type 14 (PTPN14) was chosen to reconfirm by Western blotting and semi-quantitative reverse transcription polymerase chain reaction. For clinical application, Western blotting and real-time reverse transcription polymerase chain reaction was performed to compare the expression level of PTPN14 in (Group 2 subjects) nine normozoospermic controls and thirty-three asthenozoospermic patients (including 21 mild asthenozoospermic cases and 12 severe cases). Finally, bioinformatic tools prediction and immunofluorescence assay were performed to elucidate the potential localization of PTPN14.ResultsThe expression levels of three proteins were observed to be lower in the moderate-motile sperm fraction than in good-motile sperm of group 1 subjects. Among three proteins with persistent down-regulation in the moderate-motile sperm, we reconfirmed that the expression level of PTPN14 was significantly lower in both mRNA and protein levels from the moderate-motile sperm fraction. Further, down-regulation of PTPN14 was found at the translational and transcriptional level in the asthenozoospermic men. Finally, Bioinformatic tools prediction and immunofluorescence assay showed that PTPN14 maybe predominantly localized at the mitochondria in the midpiece of human ejaculated sperm.ConclusionsProteomics tools were applied to identify three possible sperm motility-related proteins. Among these proteins, PTPN14 was highly likely a novel sperm-motility biomarker and a potential mitochondrial protein.

Association of aberrant expression of sex-determining gene fibroblast growth factor 9 with Sertoli cell–only syndrome

OBJECTIVE To investigate the expressions of fibroblast growth factor 9 (FGF9) in normal testes and in testes with Sertoli cell-only syndrome (SCOS), explore the biological function of testicular FGF9, and identify the sequence variants of FGF9 gene in patients with SCOS. DESIGN Retrospective case study. SETTING University reproductive clinic. PATIENT(S) Forty-one patients with SCOS, seven with normal spermatogenesis, and 100 controls. INTERVENTION(S) Protein expressions of testicular FGF9 and sequence variants of FGF9 gene in normal controls and patients with SCOS were studied. The biological function and regulation of testicular FGF9 were assessed in vitro. MAIN OUTCOME MEASURE(S) Expression profiles of testicular FGF9, effects of FGF9 on germ cell proliferation, and sequence variants of the FGF9 gene. RESULT(S) FGF9 was predominately expressed in the cytoplasm of Leydig cells of normal testis; its expression was significantly decreased in patients with SCOS. Conditioned medium of FGF9-treated Leydig cells stimulated germ cell proliferation. A promoter polymorphism (c.-712C→T) of the FGF9 gene attenuated the promoter activity, which contributes to one of the causes of its low expression. CONCLUSION(S) In addition to the role of sex determination, FGF9 is expressed in postnatal Leydig cells and is involved in cell-to-cell interaction of testicular function. Aberrant expression of testicular FGF9 is associated with SCOS.

A polymorphism that affects E2F1 binding to the FGF9 promoter region influences germ cell proliferation and is associated with sertoli cell-only syndrome

Objective Fibroblast growth factor 9 (FGF9) is known as one of the sex-determining genes essential for testicular embryogenesis. Fgf9 null mice appear to have testicular hypoplasia or male-to-female sex reversal. The objective of this study is to explore the role of FGF9 in male infertility. Design This study was conducted to identify the sequence variants of FGF9 gene in infertile men with Sertoli cell-only syndrome (SCOS), to investigate the expression profile of FGF9 in the normal and SCOS testes, and to study the effects of FGF9 on testicular cell proliferation. Materials and Methods A total of 41 SCOS patients, seven men with obstructive azoospermia and 79 unrelated healthy controls were enrolled. The sequence variants of the FGF9 were determined using an ABI PRISM 377 DNA sequencer. Protein expressions of testicular FGF9 in normal and SCOS testes were determined by immunohistochemical (IHC) staining and quantitative IHC. The biological function of testicular FGF9 was assessed by cell proliferation assay. Results A promoter polymorphism c.-712C>T is associated with susceptibility to SCOS and attenuates the promoter activity. Patients with c.-712C>T possess the lower FGF9 expressions, compared to normal and -712C SCOS testes. E2F1, a strong transcriptional factor, can interact with -712 oligonucleotide and mutagenic oligonucleotide (-712T) reduces the binding interaction. FGF9 is expressed in the adult germ cells, Sertoli cells and Leydig cells of human testis. FGF9 expressions are significantly decreased in the Sertoli cells and Leydig cells of SCOS testes and correlated with serum hormonal parameters. Conditioned media of FGF9-treated Leydig cell and FGF9-treated Sertoli cell promote germ cell proliferation. Conclusion FGF9 promoter polymorphism c.-712C>T affects E2F1 binding, decreases testicular FGF9 expression and is associated with SCOS. FGF9 acts as a local regulator of testicular function by influencing germ cell proliferation.