E1A stimulates FGF-2 release promoting differentiation of primary endothelial cells

Area of Science:

• Molecular Biology
• Cell Biology
• Angiogenesis Research

Background:

• Basic Fibroblast Growth Factor (FGF-2) is a key regulator of vascular system development and function.
• Adenoviral oncoprotein E1A is known to influence cellular processes, but its role in regulating FGF-2 and angiogenesis requires further elucidation.

Purpose of the Study:

• To investigate the role of adenoviral oncoprotein E1A in regulating FGF-2 production in primary bovine aortic endothelial cells (BAEC).
• To determine if E1A-induced changes in BAEC contribute to a pro-angiogenic phenotype.

Main Methods:

• Transfection of primary bovine aortic endothelial cells (BAEC) with wild-type (wt) E1A proteins (12S and 13S) and a mutant (dl646N).
• Assessment of BAEC differentiation on Matrigel, cell invasion, and migration.
• Zymography and RT-PCR to analyze matrix metalloproteinase-9 (MMP-9) and FGF-2 expression at protein and mRNA levels.
• FGF-2 neutralization experiments.

Main Results:

• Wild-type E1A (wtE1A) transfection stimulated BAEC differentiation, invasion, and migration, an effect not observed with the dl646N mutant.
• wtE1A transfection led to increased MMP-9 protein and mRNA levels.
• BAEC transfected with wtE1A exhibited elevated FGF-2 mRNA and protein levels.
• Neutralization of FGF-2 significantly reduced MMP-9 release and inhibited BAEC differentiation.

Conclusions:

• Adenoviral oncoprotein E1A promotes a pro-angiogenic phenotype in BAEC, characterized by enhanced differentiation, invasion, and migration.
• E1A upregulates FGF-2 production, which plays a critical role in mediating these pro-angiogenic effects.
• The mechanism involves an autocrine/paracrine FGF-2 signaling loop activated by E1A, leading to increased MMP-9 expression and activity.