Wnt7b is involved in axon differentiation and elongation in hippocampal neurons.

NEILA, LORENA; ROSSO SILVANA

Córdoba

Congreso; XXIII Reunión Anual SAN; 2018

Sociedad Argentina de Investigaciones en Neurociencia

The establishment of neuronal polarity and the development of axon and dendrites are essential for the formation of neuronal circuits. Wnt factors are secreted proteins functioning as neuronal modulators since are involved in neuronal differentiation, maturation and synapses. After Wnts bind to Frizzled (Fz) receptors, different signaling cascades can be activated: Wnt/β-catenin, planar cell polarity (PCP) and Wnt/Calcium pathways. Previously, we demonstrated that Wnt7b, through Fz7 receptor, regulates dendrite development and maturation activating JNK and CaMKII mediated pathways. Now, we investigated the potential role of Wnt7b during early stages of neuronal development. Our findings showed that neuronal differentiation is altered after Wnt7b stimulation. The presence of Wnt7b stimulated axonal outgrowth and elongation compared to controls. Surprisingly, the function of Wn7b on neuronal differentiation did not seem to be mediated by Fz7 receptor, since the expression of Fz7 did not affect axonal growth. Also, we found that Wnt7b effect was blocked when neurons were cultured in the presence of SFRP1 (the antagonist of Wnt), suggesting the specificity of Wnt effect on axonal growth. To go further, we examined the intracellular cascades triggered by Wnt7b. Pharmacological inhibition revealed that Wnt7b requires JNK activation to modulate the development of axon. More analyses are being performed in order to fully evaluate the Wnt7b function on early neuronal development.