Urokinase-type plasminogen activator and its receptor (uPA-uPAR complex) in CNS development: one trigger, multiple targets.

LINO NOELIA; CROMBERG LUCAS; BARBER MARIANA; DUARTE SANTIAGO; TERUEL LUISA; SANCHEZ VIVIANA

Bahia Blanca Argentina

Workshop; Neuronal communication: fromstructure to physiology. SANLino Noelia; 2008

Sociedad Argentina de Investigaciones en Neurociencias

Urokinase-type plasminogen activator and its receptor (uPA-uPAR complex) in CNS development: one trigger, multiple targets. Lino Noelia1, Cromberg Lucas1, Barber Mariana1, Duarte Santiago1, Teruel Luisa1, Sanchez Viviana1 1Inst. Biología Celular y Neurociencias “Prof. E. de Robertis” Fac. de medicina Univ. de Buenos Aires.   Urokinase-type plasminogen activator (uPA), the uPA inhihitor (PAI) and its receptor (uPAR) are a multifunctional protein complex that has been involved in cell proliferation, differentiation and migration during the embryo development. The aims of this work are (a) to investigate the rol uPA-PAI1 complex and uPAR in cell migration and neuritogenesis in vitro using the avian optic tectum (OT) and (b) to identify the co-receptor associated to uPAR in the cell surface. Methods: OT obtained from embryos of 6 days were dissected. OT Fragments were culture in DMEM with glutamine and N2, at 37ºC for 20 hours and then submitted to different treatments: (1) stimulation with uPA  (final concentration: 1.5 nM), for 30 minutes (2) generation of a gradient of uPA by using uPA absorbed to plastic beads (3) 4 hours of treatment with uPA, PAI1 or both at different concentrations between 0.37 nM and 3 nM. After treatments (1) and (2) explants were immunostained with anti-Sonic hedgehog (DSHB final dilution 2mg/ml), anti-a5, a6 and b1 integrin subunits (DSHB final dilution 2mg/ml) or anti- uPAR (Santa Cruz®, final dilution 0.2 mg/ml). Phalloidin-rhodamine (Sigma®, 1/1000) staining were used to detect actin cytoskeleton. With regards to (3) explants were photographed at the beginning and at the end of above mentioned condition. Two parameters were evaluated: cell migration pattern and axonal length. Results: uPA-PAI increase the number of migrating cells in a dose-dependent manner. (2) uPA increases sonic hedgehog expression. (3) uPA modifies the cytoskeleton organization increasing the actin stress fibers assembly. (4) A co-localization of b1 integrin subunit and uPAR was demonstrated. These results indicate that uPA-uPAR complex actively participates in the process of cell migration and neuritogenesis. The increase in Sonic hedgehog expression in treated explants suggests that uPA may activate factors involved in CNS development. This work was supported by grants from UBACYT and CONICET. Argentina.