Involvement of fibronectin type II repeats in the efficient inhibition of gelatinases A and B by long-chain unsaturated fatty acids

The matrix metalloproteinases gelatinase A (MMP-2) and gelatinase B (MMP-9) are implicated in the physiological and pathological breakdown of several extracellular matrix proteins. In the present study, we show that long-chai n fatty acids (e.g. oleic acid, elaidic acid, and cis- and trans-parinaric acids) inhibit gelatinase A as well as gelatinase B with K-i values in the micromolar range but had only weak inhibitory effect on collagenase-1 (MMP- 1), as assessed using synthetic or natural substrates, The inhibition of ge latinases depended on fatty acid chain length (with C18 > C16, C14, and C10 ), and the presence of unsaturations increased their inhibitory capacity on both types of gelatinase, Ex vivo experiments on human shin tissue section s have shown that micromolar concentrations of a long-chain unsaturated fat ty acid (elaidic acid) protect collagen and elastin fibers against degradat ion by gelatinases A and B, respectively. In order to understand why gelati nases are more susceptible than collagenase-1 to inhibition by long-chain f atty acids, the possible role of the fibronectin-like domain (a domain uniq ue to gelatinases) in binding inhibitory fatty acids was investigated. Affi nity and kinetic studies with a recombinant fibronectin-like domain of gela tinase A and with a recombinant mutant of gelatinase A from which this doma in had been deleted pointed to an interaction of long-chain fatty acids wit h the fibronectin-like domain of the protease, Surface plasmon resonance st udies on the interaction of long-chain fatty acids with the three individua l type II modules of the fibronectin-like domain of gelatinase A revealed t hat the first type II module is primarily responsible for binding these com pounds.