IQUIFIB   02644
INSTITUTO DE QUIMICA Y FISICOQUIMICA BIOLOGICAS "PROF. ALEJANDRO C. PALADINI"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
MAS RECEPTOR TRAFFICKING IN PHYSIOLOGICAL AND PATHOLOGICAL SITUATIONS AS IN HYPERTENSION
Autor/es:
MICAELA CERNIELLO, NADIA LONGO CARBAJOSA, BRUNO CERRATO, HERNÁN GRECCO, MARIELA GIRONACCI
Lugar:
CABA
Reunión:
Congreso; III international Congress in translational medicine; 2016
Institución organizadora:
FACULTAD DE FARMACIA Y BIOQUÌMICA
Resumen:
Angiotensin (Ang) (1-7) is the endogenous ligand for the G protein-coupled receptor Mas, a receptor (R) associated with cardiac, renal and cerebral protective responses. Receptor (R) trafficking has critical function in signal termination and propagation as well as receptor resensitization. Thus, the spatial and temporal control of R determines the specificity of receptor-mediated signal transduction among the distinct downstream effectors and the ultimate cellular response. Alteration in R trafficking has been associated with development of different diseases. Our aim was to investigate the angiotensin (Ang) (1-7) MasR trafficking upon agonist stimulation in physiological and pathological situations as in hypertension. Human embryonic kidney (HEK) 293T cells transfected with the coding DNA for Mas R fused to fluorescent protein YFP (MasR-YFP) (HEK293T-RMas-YFP) and neurons from brainstem of Wistar-Kyoto (WKY) or spontaneously hypertensive rats (SHR) were used. MasR-YFP internalization was evaluated by [125I]Ang-(1-7) endocytosis. MasR trafficking was evaluated by colocalization with specific trafficking markers. MasR-YFP internalization was blocked in the presence of negative dominants for caveolin and clathrin suggesting that the R is internalized through a clathrin- and caveolin-mediated pathways. MasR-YFP colocalized with Rab11, the slow recycling vesicle marker, and not with Rab4, the fast recycling vesicle marker or Lamp-1, the lysosome marker, indicating that the R, once internalized, is slowly recycled back to the plasma membrane. Similar results were observed in neurons from brainstem of WKY and SHR: the R was internalized and targeted to early endosomes after Ang-(1-7) stimulation and then recycled back to the plasma membrane. However, the fraction of internalized R was greater in neurons from SHR compared to WKY, and the fraction of R that was recycled black to the plasma membrane was lesser in SHR than in WKY. Surprisingly, a fraction of MasR of neurons of SHR stimulated with Ang-(1-7) colocalized with a neuronal marker, suggesting that the R was targeted to the nucleus upon agonist stimulation. MasR expression measured by Western-blot was significantly greater in nucleus from Ang-(1-7) stimulated neurons of SHR vs WKY, reinforcing the concept of R targetted to the nucleus in SHR upon agonist stimulation. Our results show that MasR displayed a differential trafficking in hypertension: greater amount of R internalized, lower amount of R recycled back to the membrane and targetting to the nucleus. In this way, a lesser amount of MasR may be present in the plasma membrane to be activated. This differential trafficking may contribute to the development of hypertension.