FGF2-Induced adenohypophysary cell proliferation is regulated by inhibitory GPCR

LILIANA DEL VALLE SOSA, ISABELLA HEIRNRICH, NATACHA ZLOCOWSKI, FLORENCIA PICECH, CAROLINA GUIDO, SILVINA GUTIÉRREZ, JUAN PABLO PETITI, ROBRIGO LEAL, ANA DE PAUL, ALICIA TORRES

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedad Argentina de Investigación Clínica

The metabolic activity of pituitary gland is regulated by numerousfactors being the basic fibroblast growth factor (FGF2), one ofthe main regulator that increase of pituitary cell proliferation. Thegrowth factors effects may be regulated by activation of inhibitoryG protein-coupled receptors (GPCRs) at different signaling levels.The aim of this work was to evaluate whether the FGF2 proliferativeactivity in adenohypophysis cells is regulated by inhibitory GPCRsactivated by the somatostatin analogue, octreotide (OCT). Anteriorpituitary cell cultures from female rats were treated with FGF2 (10ng/mL) or OCT (100mM) alone or co-incubated, in serum free condition.The cell cycle was analyzed using propidium iodide by flowcytometry at 24 and 48h. The mRNA levels of cell cycle regulators(tp53, cdkn1a, cdk4 and ccdn1) were determined by qPCR at 3 or6h and the total and phosphorylated (p) ERK1/2, JNK, p38 and Aktprotein expression by western blot at 15, 30, 60 or 90 min. Statistics:ANOVA-Bonferrony. The S/G2M phases were increased by FGF2whereas OCT decreased these phases. The FGF2/OCT co-incubationsignificantly increased the G1-phase arrest after 24 and 48 h,effect that was associated with an increase of cdkna1 and decreaseof ccdn1 mRNA levels at 3 and 6h, while the tp53 and cdk4 didnot show any significant variation. In addition, even though pP38and pAkt protein expression levels did not presented changes, aremarkable decrease of pERK1/2 expression was observed in alltimes analyzed, and a significant increase of pJNK expression at60 and 90min was detected after combined treatments These findingsshow that FGF2/OCT treatment inhibited proliferation inducedby FGF2 in pituitary cell culture regulating the pERK1/2 and pJNKprotein expression and the cdkn1a and ccdn1 cell cycle regulatedgenes. This regulatory effect may participate in the homeostasis ofpituitary cell populations.Keywords: pituitary cell, , FGF2, inhibitory GPCR, cell cycle,ERK1/2