Human fibrinogen specifically binds hyaluronic acid

Area of Science:

• Biochemistry
• Extracellular Matrix Biology

Background:

• Fibrinogen and hyaluronic acid (HA) concentrations increase in damaged tissues.
• Understanding molecular interactions in tissue repair is crucial.

Purpose of the Study:

• To investigate the binding interaction between hyaluronic acid (HA) and fibrinogen.
• To characterize the specificity and affinity of this interaction.

Main Methods:

• Solid-phase and soluble binding assays using HA-Sepharose chromatography.
• Radioiodinated fibrinogen (125I-fibrinogen) and HA of varying molecular weights were used.
• Displacement assays with free HA, monosaccharides, and other polysaccharides were performed.

Main Results:

• Purified human fibrinogen demonstrated specific binding to HA-Sepharose, significantly exceeding binding to control proteins.
• Enzymatic degradation with hyaluronidase released bound fibrinogen, confirming specific HA interaction.
• Binding affinity increased with HA molecular weight, with optimal binding observed for larger HA polymers (≥200 monosaccharides).
• The affinity constant for fibrinogen binding to HA was estimated to be at least 2 x 10^7 M-1.

Conclusions:

• A specific and reversible binding interaction exists between fibrinogen and hyaluronic acid (HA).
• This interaction is dependent on the size of the HA polymer.
• These findings elucidate a novel molecular interaction relevant to tissue repair and extracellular matrix dynamics.