Human SPRY2 inhibits FGF2 signalling by a secreted factor

Area of Science:

• Cellular and Molecular Biology
• Developmental Biology
• Signaling Pathways

Background:

• Growth factor signaling pathways are crucial for vertebrate and invertebrate development.
• Spry proteins act as negative regulators of fibroblast growth factor (FGF) signaling.
• The precise role of human SPRY2 in FGF signaling remains largely uncharacterized.

Purpose of the Study:

• To investigate the function of the human SPRY2 gene in fibroblast growth factor 2 (FGF2) signaling.
• To elucidate the mechanism by which SPRY2 influences cell proliferation.

Main Methods:

• Quantitative analysis of SPRY2 mRNA expression in human microvascular endothelial cells (MVEC) upon FGF2 stimulation.
• Overexpression of SPRY2 in A375 cells and assessment of secreted factors' effects on MVEC proliferation.
• Investigation of SPRY2 protein localization using SPRY2/GFP fusion proteins and interaction studies with GRB2.

Main Results:

• FGF2 stimulation transiently upregulates SPRY2 mRNA in MVEC.
• SPRY2 overexpression induces secretion of a factor inhibiting FGF2- but not VEGF-stimulated MVEC proliferation.
• SPRY2 protein interacts with GRB2 and localizes intracellularly, suggesting a role in non-cell autonomous inhibition.

Conclusions:

• SPRY2 plays an indirect role in the non-cell autonomous inhibition of FGF2 signaling.
• SPRY2 regulates the secretion of an FGF inhibitor, impacting vertebrate development.
• This study provides the first evidence of SPRY2's involvement in regulating FGF2 signaling pathways in vertebrates.