FGF2-Induced adenohypophysary cell proliferation is regulated by inhibitory GPCR

SOSA L DEL V.; HEIRNICH I; ZLOCOWSKI N; PICECH, F; GUIDO, C; GUTIÉRREZ, S; PETITI J P; LEAL, R; DE PAUL, A L; TORRES, A I

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias. Buenos Aires; 2017; 2017

Sociedades de Biociencias

The metabolic activity of pituitary gland is regulated by numerous factors being the basic fibroblast growth factor (FGF2), one of the main regulator that increase of pituitary cell proliferation. The growth factors effects may be regulated by activation of inhibitory G protein-coupled receptors (GPCRs) at different signaling levels. The aim of this work was to evaluate whether the FGF2 proliferative activity in adenohypophysis cells is regulated by inhibitory GPCRs activated by the somatostatin analogue, octreotide (OCT). Anterior pituitary cell cultures from female rats were treated with FGF2 (10 ng/mL) or OCT (100mM) alone or co-incubated, in serum free condition. The cell cycle was analyzed using propidium iodide by flow cytometry at 24 and 48h. The mRNA levels of cell cycle regulators (tp53, cdkn1a, cdk4 and ccdn1) were determined by qPCR at 3 or 6h and the total and phosphorylated (p) ERK1/2, JNK, p38 and Akt protein expression by western blot at 15, 30, 60 or 90 min. Statistics: ANOVA-Bonferrony. The S/G2M phases were increased by FGF2 whereas OCT decreased these phases. The FGF2/OCT co-incubation significantly increased the G1-phase arrest after 24 and 48 h, effect that was associated with an increase of cdkna1 and decrease of ccdn1 mRNA levels at 3 and 6h, while the tp53 and cdk4 did not show any significant variation. In addition, even though pP38 and pAkt protein expression levels did not presented changes, a remarkable decrease of pERK1/2 expression was observed in all times analyzed, and a significant increase of pJNK expression at 60 and 90min was detected after combined treatments These findings show that FGF2/OCT treatment inhibited proliferation induced by FGF2 in pituitary cell culture regulating the pERK1/2 and pJNK protein expression and the cdkn1a and ccdn1 cell cycle regulated genes. This regulatory effect may participate in the homeostasis of pituitary cell populations.