血清レクチンとメタロプロテアーゼとの相互作用のもつ生理的・病理的意義

Abstract

Mannan-binding protein (MBP) is a Ca^<2+>-dependent lectin known as a host defense factor involved in innate immunity, and recognizes mannose, fucose, and N-acetylglucosamine residues. The biological responses of MBP to exogenous ligands have been studied extensively, however, little is known about its role to endogenous ligands. We have identified meprins, matrix metalloproteases, as novel endogenous MBP ligands in the renal proximal tubules of mouse. We found that the binding of MBP to meprins resulted in significant decreases in the proteolytic and matrix-degrading activities, indicating that MBP is an important regulator for the local modulation of meprin proteolytic activity. On the other hand, focusing on the pathogenic role of the interaction of MBP with meprins, we clarified that, in an acute renal failure caused by ischemia/reperfusion injury, the binding of MBP with meprins triggers the complement activation on the renal proximal tubules through the lectin pathway.