title: Activated α2-macroglobulin induces Müller glial cell migration by regulating MT1-MMP activity through LRP1.
abstract: In retinal proliferative diseases, Müller glial cells (MGCs) acquire migratory abilities. However, the mechanisms that regulate this migration remain poorly understood. In addition, proliferative disorders associated with enhanced activities of matrix metalloprotease 2 (MMP-2) and MMP-9 also present increased levels of the protease 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 form of α2M, α2M*, and LRP1 are involved with the MGC migratory process. By performing wound-scratch migration and zymography assays, we demonstrated that α2M* induced cell migration and proMMP-2 activation in the human Müller glial cell line, MIO-M1. This induction was blocked when LRP1 and MT1-MMP were knocked down with siRNA techniques. Using fluorescence microscopy and biochemical procedures, we found that α2M* induced an increase in LRP1 and MT1-MMP accumulation in early endosomes, followed by endocytic recycling and intracellular distribution of MT1-MMP toward cellular protrusions. Moreover, Rab11-dominant negative mutant abrogated MT1-MMP recycling pathway, cell migration, and proMMP-2 activation induced by α2M*. In conclusion, α2M*, through its receptor LRP1, induces cellular migration of Müller glial cells by a mechanism that involves MT1-MMP intracellular traffic to the plasma membrane by a Rab11-dependent recycling pathway.
authors: Centro de Investigaciones en Bioquímica Clínica e Inmunología-Consejo Nacional de Investigaciones Cientificas y Tecnicas (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, (5000) Córdoba, Argentina.
authors: Pablo F
authors: PF
authors: Barcelona
authors: Javier R
authors: JR
authors: Jaldín-Fincati
authors: María C
authors: MC
authors: Sánchez
authors: Gustavo A
authors: GA
authors: Chiabrando
mesh_terms: D002352:Carrier Proteins / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects*; D004705:Endocytosis / Q000187:drug effects; D011992:Endosomes / Q000378:metabolism; D005982:Glutathione Transferase / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D008954:Models, Biological; D009154:Mutation; D009457:Neuroglia / Q000166:cytology; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D000511:alpha-Macroglobulins / Q000494:pharmacology*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D002352:Carrier Proteins; D005982:Glutathione Transferase; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008164:Luminescent Proteins; D053511:Matrix Metalloproteinase 14; D011993:Recombinant Fusion Proteins; D000511:alpha-Macroglobulins; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C475476:LRP1 protein, human; C103332:GST-RAP protein, recombinant
keywords: endocytosis; intracellular traffic; proteases; retina; retinopathies