GDNF enhances HGF-induced tubulogenesis and organization of Sertoli cell.

PURPOSE: Hepatocyte growth factor (HGF), secreted by Sertoli cells, activates the c-Met receptor, facilitating seminiferous tubule formation. Glial cell-derived neurotrophic factor (GDNF) promotes embryonic Sertoli cell proliferation and cord formation. This study aimed to investigate whether exogenous GDNF contributes to HGF-induced in vitro organization of Sertoli cells in a Matrigel-based three-dimensional (3D) culture system. METHODS: Four experimental groups were established using the 15P-1 Sertoli cell line: control, HGF-treated, GDNF-treated, and combined HGF- and GDNF-treated. Tubular structure length and branching were quantified using image analysis software, while the expression of ZO-1 protein was assessed via immunofluorescence staining in 3D Matrigel-based culture for 5 days. Additionally, Gfrα-1, Ret, Ncam, and Met mRNA expression in Sertoli cells were analyzed. The expression levels of ZO-1, c-MET, and p-c-MET were analyzed in two-dimensional (2D) culture after 5 days. RESULTS: Quantitative analysis revealed a significant increase in the length and branching of tubular-like structures when GDNF was co-administered with HGF, compared to other groups. Additionally, there was a notable increase in ZO-1 protein expression with the combined administration of GDNF and HGF, surpassing levels observed in the control group. Furthermore, co-administration of HGF and GDNF significantly elevated phospho-c-Met levels compared to the control group. CONCLUSION: Our study reveals that exogenous GDNF enhances the HGF-induced tubular organization of Sertoli cells in vitro. The concurrent administration of GDNF and HGF markedly augments the formation of tubular structures and the expression of the ZO-1 protein, indicating a potential synergistic influence on the organizational and signaling cascades within Sertoli cells.