MEK / ERK ARE INVOLVED IN THE DISINSERSION OF THE MRP2 TRANSPORTER IN CHOLESTASIS INDUCED BY IL-BETA.

SCHUCK, VIRGINIA S.; ANDERMATTEN, ROMINA B.; CIRIACI, NADIA; SALAS, GIMENA; MEDEOT, ANABELA C.; BAROSSO, ISMAEL R.; SANCHEZ POZZI EJ

Mar del Plata

Congreso; Reunión Anual de la SAIC; 2020

Sociedad Argentina de Investigación Clínica

Inflammatory cytokines produce alterations in the location and function of canalicular transporters and could mediate the biliary secretory failure observed in inflammatory-associated pathologies such as sepsis. This action of cytokines is mediated by activation of signaling proteins. Our aim was to study which signaling proteins are involved in the cholestasis model induced by one of these cytokines, IL-1β, and to analyze the location of the Mrp2 transporter using confocal image analysis. In particular, we analyze the role of MEK / ERK proteins using the isolated rat hepatocyte couplet (IRHC) model. Methodology: IRHCs were pre-incubated for 15 minutes with the MEK1 / 2 inhibitor, PD980589 (PD 5 μM), followed by incubation with IL-1β (10 ng / ml, 20 minutes). Then, they were exposed to chloro-methylfluorescein diacetate (2.5 μM, 15 min) converted intracellularly into glutathione methylfluorescein (GMF), an Mrp2 substrate. Finally, Mrp2 activity was estimated by the percentage of IRHC that accumulated GMF in the canalicular vesicle (cVA). At the same time, activation of the MEK / ERK pathway was estimated in isolated hepatocytes treated with IL1β by evaluating ERK phosphorylation by Western Blot. To confirm whether IL-1β produces internalization of Mrp2, IRHCs treated with IL-1β were studied by immunostaining followed by confocal microscopy.Results: (% of control ± SE): IL-1β significantly reduced Mrp2 activity (cVA: IL-1β = 51 ± 4% a). This was prevented by PD (97 ± 2% b). Treatment with IL1β caused an increase in phosphorylated levels of ERK after 20 min (IL: 210 ± 25% a). a different from control, b different from IL. P