Modulation of protease nexin-1 activity by polysaccharides

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Protease Nexin-1 (PN-1) is a pericellular serpin regulating proteases, particularly thrombin, when bound to glycosaminoglycans.
• Fucoidans, sulfated polysaccharides, possess antithrombotic properties and interact with serpins, offering a potential alternative to heparin with reduced hemorrhagic risk.

Purpose of the Study:

• To compare the effects of low (LMW) and high molecular weight (HMW) fucoidans with standard and LMW heparin on PN-1 properties.
• To investigate the interaction of fucoidans and heparins with PN-1 and thrombin.
• To assess the impact of these polysaccharides on cell-associated PN-1.

Main Methods:

• Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS).
• Affinity coelectrophoresis.
• Progress curve kinetics to measure thrombin inhibition rates.
• Cell culture experiments to study PN-1 detachment from smooth muscle cells.

Main Results:

• Fucoidans and heparins bound to thrombin, PN-1, and the thrombin/PN-1 complex.
• LMW and HMW fucoidans accelerated thrombin inhibition by PN-1 significantly more than LMW heparin.
• Fucoidans and heparins detached cell-membrane-bound PN-1, which retained thrombin inhibitory activity.

Conclusions:

• Fucoidans effectively reduce cell-associated PN-1 and thrombin/PN-1 complexes.
• Fucoidans enhance the antithrombin activity of PN-1, suggesting therapeutic potential.
• PN-1's role in regulating pericellular thrombin activity highlights the therapeutic interest of fucoidans.