Controlled organization of insulin nanofilms modulates neuron polarization in solid-supported cultures.

GRASSO, ERNESTO ; RAFAEL GUSTAVO OLIVEIRA; OKSDATH, MARIANA; QUIROGA, SANTIAGO; MAGGIO, B.

San Javier, Tucumán

Congreso; XLI Reunión Anual de la Sociedad Argentina de Biofísica; 2012

Sociedad argentina de Biofísica

Neurons are highly polarized cells, composed of one axon and several branching dendrites. One important issue in neurobiology is to understand the molecular factors that determine the neuron to develop polarized structures. A particularly early event, in neurons that do not yet exhibit a discernible axon, is the segregation of activatable IGF-1 (Insulin like Growth Factor-1) receptors in one neurite. This receptor can be activated by insulin in bulk. Nevertheless, it is not known if changes of the organization of insulin as a monomolecular film can affect the induction of neuron polarization. In this work we developed two kind of solid-supported  Langmuir-Blodgett insulin nanofilms. Hyppocampal pyramidal neurons, in early stage of differentiation, were cultured onto the substrates and polarization was studied after 24 hs by confocal microscopy. Also we used surface reflection interference contrast microscopy (SRIC) to study attachment patterns and morphology of growth cones. We observed that insulin nanofilms packed at 14 mN/m induced polarization in a similar manner to high insulin concentration in bulk. However, insulin nanofilms packed at 44 mN/m did not induce polarization. Thus, our results provide novel evidence that the neuron polarization through IGF-1 receptor activation can be selectively modulated by the lateral packing of insulin organized as a monomolecular surface for cell growth.