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; SÁNCHEZ POZZI, ENRIQUE J

Rosario

Congreso; REUNIÓN ANUAL DE SOCIEDADES DE BIOCIENCIAS SAIC - SAI - SAFIS; 2020

Sociedad Argentina de Fisiología-Sociedad Argentina de Investigacion Básica

Inflammatory cytokines produce alterations in the location and functionof canalicular transporters and could mediate the biliary secretoryfailure 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 proteinsusing 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 chloromethylfluoresceindiacetate (2.5 μM, 15 min) converted intracellularlyinto 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 hepatocytestreated 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 followedby 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 differentfrom IL. P