CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Beyond endocytosis: LRP-1 function in M¨¹ller glial cell migration¡±
Autor/es:
SANCHEZ MC,; BARCELONA PF; JALDIN-FINCATI J; LORENC VE; CHIABRANDO GA
Lugar:
Buzios BRASIL
Reunión:
Congreso; I CONGRESS IBRO/LARC OF NEUROSCIENCES FOR LATIN AMERICA, CARIBBEAN AND IBERIAN PENINSULA.; 2008
Institución organizadora:
IBRO
Resumen:
Beyond endocytosis: LRP-1 function in M¨¹ller glial cell migration. S¨¢nchez MC, Barcelona PF, Jald¨ªn-Fincati JR, Lorenc VE, Chiabrando G. CIBICI (CONICET)-Dpto de Bioqu¨ªmica Cl¨ªnica. Facultad de Ciencias Qu¨ªmicas. Universidad Nacional de C¨®rdoba. Argentina. Purpose: M¨¹ller cells (MC) are known to undergo functional and morphological changes and to produce matrix metalloproteinases (MMPs) during retinal proliferative diseases. Alpha 2- macroglobulin (¦Á2-M) receptor (LRP-1) is a large endocytic receptor expressed in most cell types. In previous studies we have demonstrated that MC express LRP-1 and its ligand, ¦Á2-M, is able to induce MMP-2 activity. However, the biochemical mechanism by which ¦Á2-M/LRP-1 system may control this activity is unclear, which could involve both endocytic and intracellular pathways activation. Herein we investigate the putative mechanisms of a2-M/LRP-1 system on the MMPs regulation and cell migration in a M¨¹ller cell line. Methods: The human MIO-M1 was cultured in the absence or presence of 60 nM a2-M for different time periods. The effect of a2-M on MMPs activity was evaluated in MC supernatants by zymography. The expression level of MT1-MMP was analyzed by RT-PCR, Western blot (WB) and immunofluorescence (IF) analysis. MMP-2 and TIMP-2 expression were also examined by RT-PCR. Cell migration was evaluated on collagen or laminin-coated surface using time-lapse video microscopy. The a2-M induced signalling pathways were evaluated by WB. Cell binding and internalization of a2-M were evaluated by flow cytometry using anti LRP-1:RPE and Alexa fluor 488-conjugated a2-M. Results: By zymography we observed that a2-M increased MMP-2 activity whereas MMP-9 activity was not modified. a2-M also increased MT1-MMP and TIMP-2 mRNA and MT1-MMP protein, which was associated with the MMP-2 activity. Under a2-M induction MT1-MMP was localized at the cell surface of MC. This MMPs regulation was also accompanied by an increase of cell motility on coated surfaces. Finally, using pharmacological inhibitors of signaling pathways and endocytosis we observed that MMPs regulation and MIO-M1 cell migration were dependent on the intracellular signal activation induced by the a2-M/LRP-1 system. Conclusion: The present study demonstrates that the a2-M/LRP-1 system regulates the proteolytic activity of MMP-2 in MIO-M1 cells by inducing the MT1-MMP and TIMP-2 expression, suggesting that MAPK and PKB pathways are involved.