Modulation by iron of the expression of transcription factors involved in the peripheral nervous system myelinogenesis

GOITIA BELEN; USACH VANINA; MARTINEZ VIVOT ROCÍO; SETTON-AVRUJ PATRICIA

Huerta Grande, Córdoba, Argentina.

Congreso; 1º Reunión Conjunta de Neurociencias. Huerta Grande, Córdoba, Argentina.; 2009

Sociedad Argentina de Neurociencias

Modulation by iron of the expression of transcription factors involved in the peripheral nervous system myelinogenesis Belén Goitia, Vanina Usach, Rocío Martínez Vivot, Patricia Setton-Avruj. Cátedra de Química Biológica Patológica, FFyB, IQUIFIB, UBA-CONICET, IIMHNO-UBA Email: verdilsoyyo@gmail.com Schwann cells (SCs) are responsible for myelination in the peripheral nervous system (PNS) and derive from neural crest cells. During the development of SC lineage there are SCs precursors (SCPs; E13-E14), immature SCs (E16-E17) and, after birth, mature myelinating and nonmyelinating SCs. Transcription factors involved in this process include Sox10, SCIP (crucial for temporal control of myelination) and Krox-20, vital for myelinogenesis and myelin maintenance. We have previously demonstrated the expression of transferrin (Tf) mRNA in SCPs and immature SCs. The aim of this work is to demonstrate a negative correlation between the expression of these factors and Tf mRNA and to study if the prodifferentiating effect of iron on SCs is mediated by the upregulation of these factors. We isolated SCPs and immature SCs from embryonic sciatic nerves (embryonic days 14, 16, 18 and 20, E14-E20) and mature SCs from 4 day old pups (P4). The cells were cultured for 3 hours (E14-E18) or 24 hours (E20 and P4) and either proteins or RNA were obtained. We have detected SCIP in E20, Krox-20 in P4 and S100 in all phases by Western blot. The presence of Krox-20 mRNA was evaluated by semiquantitative RT-PCR. It was found at all stages but its expression was stimulated by Fe3+ or fetal calf serum only in E18 and E20, suggesting that in previous phases the mechanisms by which Fe3+ or serum stimulate its expression are missing. Our results suggest that the expression of Tf is followed by that of promyelinating transcription factors. These consecutive events would modulate myelinogenesis in the PNS. This also suggests that the prodifferentiating effect iron has on SCs could be mediated by the activation of the expression of these factors.