INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Sexually dimorphic interaction between estradiol and Notch/Ngn3 signaling in hypothalamic neurons
Autor/es:
MJ SCERBO, I RUIZ-PALMERO, LM GARCIA-SEGURA, MJ CAMBIASSO, MA AREVALO
Lugar:
Potrero de los Funes, San Luis
Reunión:
Congreso; XLVII Reunión Anunal de la Sociedad Argentina de Bioquímica y biología Molecular; 2011
Institución organizadora:
Sociedad Argentina de Bioquímica y Biología Molecular
Resumen:
Previous results have demonstrated that sexually segregated hypothalamic neurons respond differentially to the hormonal environment before the masculinizing actions of gonadal steroids. At the embryonic stage 16, 17â-estradiol (E2) induces axonal growth only in male hypothalamic neurons. Recent studies have shown that E2 and Notch signaling converge to control neuritogenesis in hippocamapal neurons. Activation of Notch is associated with an enhancement of the expression of the transcription factors Hes1 and Hes5, which negatively regulate the proneural gene Ngn3 that is involved in neuritic growth. Using real time PCR we have detected that E14 hypothalamic neurons express Ngn3 in a sexually dimorphic pattern: female neuronal cultures had significantly higher Ngn3 mRNA levels than males. Moreover, E2 (10 nM) significantly increased Ngn3 mRNA in males, but not in females. This effect was completely blocked by the ERá/â-mediated transcription antagonist ICI 182,780 (10 ìM). In addition, male neuronal cultures had significantly higher Hes1 mRNA levels than females and E2 significantly reduced Hes1 mRNA levels in males, but not in females. The effect of the hormone on Hes1 was also blocked by ICI 182,780. These results suggest that E2 and Notch signaling pathways interact in hypothalamic neurons with a sexually dimorphic pattern even before the organizational effect of gonadal steroids