A NOVEL SIGNALING MECHANISM OF ANGIOTENSIN II AT2 RECEPTORS IN NEURONAL DIFFERENTIATION

BLANCO, HM; ALVAREZ SE; CIUFFO GM

Bariloche

Simposio; SISTAM 2015; 2015

A NOVEL SIGNALING MECHANISM OF ANGIOTENSIN II AT2 RECEPTORS IN NEURONAL DIFFERENTIATION. Helga M. Blanco1,2, Sergio E Alvarez1, Gladys M. Ciuffo1,2. 1IMIBIO-SL, CONICET. 2Universidad Nacional de Villa Mercedes. Angiotensin II (Ang II), the active peptide of the renin-angiotensin system (RAS), elicits a variety of physiological effects through specific receptors, AT1 and AT2. The characteristic function of AT1 receptor is to control blood pressure. On the other hand, AT2 receptor?s functions are related to development processes, and may be involved in neuronal differentiation although this mechanism is not well defined. The sprouting of neurites are key morphological features characterizing neuronal differentiation. Thus, we decided to examine the rol of Ang II AT2 receptors CGP42112, in differentiation of SH-Sy5y human neuroblastoma cells. Here, we show that treatment for 3 days with either Ang II (100 nM) or CGP42112 (10 nM), a specific AT2 receptor agonist, induce neurite sprouting, as analyzed by optic microscopy (15-20 random fields were counted). Cells showing at least one neurite with a twofold length than the soma diameter were considered as differentiated. We explored the possible participation of PI3 kinase, MAPK and c-Src. Only cells pretreated with PP2, a c-Src family protein inhibitor, evidence a lower response to CGP41112A stimulation. Pre-treatment with Ly294002, the PI3 kinase inhibitor, or UO126, a MEK 1/2 inhibitor, did not influence the percentage of differentiation induced by CGP42112. These results suggest that activation of c-Src family protein through by stimulation of AT2 receptor modulate neuronal differentiation. To further explore the mechanism, we evaluated phosphorylation of c-SRC at residue Y416pSrc under the previous conditions, showing an early response between 0.25 min to 3 min. Besides, we also demonstrated the induction of AT2 receptor synthesis by stimulation of neuronal growth factor (NGF) TrkA receptors and the relation with neurite outgrowt. In summary, we demonstrated the Ang II AT2 receptors stimulation induces neuronal differentiation via activation of c-Src and the interaction between pathways of Ang II AT2 receptors and NGF.