FGF binding by extracellular matrix components of Wharton's jelly

Area of Science:

• Biochemistry
• Cell Biology
• Developmental Biology

Background:

• Wharton's jelly is a rich source of peptide growth factors, including acidic and basic fibroblast growth factors (aFGF and bFGF).
• These growth factors are typically extracted as high molecular mass complexes associated with extracellular matrix components.
• Previous studies indicate limited extractability and penetration of these complexes during standard electrophoretic analysis.

Purpose of the Study:

• To investigate the binding characteristics and extractability of aFGF and bFGF from Wharton's jelly.
• To elucidate the role of extracellular matrix components and disulfide bonds in growth factor complexation.
• To understand the implications of growth factor localization for Wharton's jelly cell activity.

Main Methods:

• Extraction of growth factors using buffered salt solutions with and without pre-treatment agents.
• Enzymatic digestion of Wharton's jelly components using hyaluronidase and bacterial collagenase.
• Electrophoretic analysis of growth factor complexes in polyacrylamide gels.
• Assessment of growth factor extractability in the presence of beta-mercaptoethanol.

Main Results:

• Hyaluronidase slightly enhanced aFGF extractability, while collagenase significantly increased bFGF extractability.
• Beta-mercaptoethanol increased the extractability of both aFGF and bFGF, indicating disulfide bond involvement, but did not yield free growth factors.
• Growth factors remained complexed, suggesting binding to a protein component via disulfide bonds within the Wharton's jelly matrix.

Conclusions:

• Acidic and basic fibroblast growth factors (aFGF and bFGF) in Wharton's jelly are bound by disulfide bonds to a protein component.
• The dense extracellular matrix, primarily collagen and hyaluronate, acts as a barrier, limiting growth factor dispersion and extraction.
• This localized concentration of growth factors likely facilitates paracrine signaling, promoting cell proliferation, differentiation, and matrix synthesis.