IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Progesterone modulates IgG N-glycosylation in vitro via two mechanisms which involve classic and membrane bound receptors
Autor/es:
MARÍA BELÉN PRADOS; JULIA LA BLUNDA; CORTINA M; JULIO CARAMELO; SILVIA MIRANDA
Lugar:
Buenos Aires
Reunión:
Congreso; 1º Congreso Franco-Argentino de Inmunología; 2010
Resumen:
Among the immunological effects of progesterone (P4), we reported an in vitro modulation of IgG1 N-glycosylation, which involves the differential expression of UDP-Glc-glucosyltransferase isoforms (GT1 and GT2). GT is part of the glycoprotein quality control mechanism. P4 effects are mainly mediated by intracellular receptors (PRs), which act as transcription factors. In addition, P4 may initiate rapid actions through activation of membrane receptors (mPR), which identities are under study. Considering the diverse effects of P4 doses over 112D5 hybridoma secreted IL-6 levels, IgG1 N-glycosylation, GT1/GT2 expression and total GT activity, we speculated that both types of receptors were involved. PRs were previously found in 112D5 hybridoma. In order to search mPR, cells were incubated with P4-BSA-FITC (0, 10-10, 10-9, 10-8, 10-6, 10-5M) during 30 min at 4ºC and analyzed by flow cytometry. A control was performed pre-incubating cells with P4 10-3M. Only cells treated with P4 10-5M were positive (70±2%). In order to establish the functionality of the P4 binding molecule, we performed P4 and P4-BSA (0, 10-5 and 10-6M) cultures and measured IgG1 glycosylation (several lectin-ELISA), GT activity (incorporation of [14C]-Glc to denatured thyroglobulin by microsomes), GT1/GT2 expression (western blot) and IL-6 (ELISA). In comparison to non treated cells, IgG1 N-glycosylation increased with P4 10-5M (23±3%) but diminished with P4-BSA (40±10%). While GT1 expression was reduced with P4 and P4-BSA (50±15%), GT2 was largely increased with P4 (90±16%) and slightly increased with P4-BSA (25±10%). GT activity was induced with P4 (30±10%) and reduced with P4-BSA (30±8%). Secreted IL-6 was undetected in P4 and P4-BSA cultures. As expected, P4-BSA 10-6M had no effect on the studied parameters.These results indicate that 112D5 hybridoma cells are able to express a functional mPR. P4 10-5M acts through PRs and mPR in hybridoma 112D5 whereas the other P4 doses act only through the first ones.