Angiotensin II AT2 receptors modulate neuronal differentiation

BLANCO H; BANCHIO C; CIUFFO GM; ALVAREZ SE

Potrero de los Funes, San Luis

Congreso; 47th Reunion Anual SAIB; 2011

Neuronal differentiation is a complex process characterized by neurite outgrowth. Binding of nerve growth factor (NGF) to the receptor TrKA induces differentiation by activating ERK pathway. In the past years it has become clear that, in addition to its cardiovascular roles, the octapeptide Angiotensin II (Ang II) has many functions in the brain by acting through two receptor subtypes, AT1 and AT2. However its role in neuronal differentiation is not well defined. Thus, we decided to examine the participation of Ang II and NGF in differentiation of Neuro2A cells with special focus in ERK activation. By RT-PCR and western blot we determined that Neuro2A cells express AT1, AT2 and TrKA receptors. Cells were stimulated with Ang II, CGP42112 (AT2 specific receptor agonist) or NGF and active ERK detected in cell lysates by western blot with specific antibodies. As expected, NGF induces ERK phosphorylation in a time dependent manner. Likewise, Ang II and CGP42112 stimulate ERK, suggesting an AT2 receptor-dependent effect. To study differentiation, cells were treated with agonists for 24 h and observed under optic and fluorescent microscopy. Both Ang II and CGP42112 induce differentiation and expression of âIII tubulin, a neuritogenesis marker. These results suggest that AT2 receptor activation induces ERK phosphorylation, expression of âIII tubulin and differentiation in Neuro2A cells.