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

SCHUCK VIRGINIA SOLEDAD; ANDERMATTEN ROMINA BELEN; CIRIACI NADIA; MEDEOT ANABELA CAROLINA; SALAS GIMENA; BAROSSO ISMAEL RICARDO; SANCHEZ POZZI ENRIQUE JUAN

Mar del ¨Plata

Congreso; Reunion Anual de Sociedades de Biociencias 2020; 2020

SAIC SAFIS

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 assepsis. This action of cytokines is mediated by activation of signalingproteins. Our aim was to study which signaling proteins are involvedin the cholestasis model induced by one of these cytokines, IL-1β,and to analyze the location of the Mrp2 transporter using confocalimage 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 theMEK1 / 2 inhibitor, PD980589 (PD 5 µM), followed by incubation withIL-1β (10 ng / ml, 20 minutes). Then, they were exposed to chloromethylfluorescein 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 thataccumulated 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 byWestern Blot. To confirm whether IL-1β produces internalization ofMrp2, 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 ofERK after 20 min (IL: 210 ± 25% a). a different from control, b different from IL. P