CONICET | Buscador de Institutos y Recursos Humanos

Introduction. In retinal proliferative diseases as well as in several inflammatory processes, Müller glial cells (MGC) and macrophages acquire migratory abilities. In addition, these disorders are associated with enhanced activities of matrix metalloprotease-2 (MMP-2) and MMP-9 together with increased levels of the protease in inhibitor α2- macroglobulin (α2M) and its receptor the low density lipoprotein receptor-related protein 1 (LRP1). In the present work, we investigated whether the protease activated or o α2M, α2M*, and LRP1 are involved with migratory process of MGC and macrophages. Material and Methods. MIO-M1 (human Müller glial-derived cells) and Raw264.7 (mouse macrophage-derived cells) were used. Wound-scratch migration and zymography assays to study cell motility and MMP activity. Fluorescence confocal microscopy to evaluate subcellular distribution of LRP1 and membrane type 1-MMM (MT1-MMP). Protein intracellular traffic of MT1-MMP and LRP1 was evaluated by FRAP, TIRFM and biotinilation assays. siRNA and shRNA techniques as well as cell transfections with different expression vectors for Rab-protein expression fused to GFP were used. Results. α2M* induced cell migration and proMMP-2 activation in cultured cells, which was blocked by silencing techniques for LRP1 and MT1-MM α2M* increased LRP1 and MT1-MMP accumulation in early endosomes, followed by endocytic recycling and intracellular distribution of MT1-MMP towards cellular protrusions. Moreover, Rab11-dn mutant abrogated MT1-MMP recycling pathway, cell migration and proMMP-2 activation induced y α2M*. Discussion. α2M*, via LRP1, induces cellular migration by a mechanism that involves MT1-MMP traffic to plasma membrane by a Rab11-dependent recycling pathway.