SPHINGOSINE 1-PHOSPHATE RECEPTOR 2 (S1PR2) IS POTENTIALLY INVOLVED IN TAUROLITHOCHOLATE (TLC)-INDUCED IMPAIRMENT OF MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN 2 (MRP2) ACTIVITY

ANDERMATTEN, ROMINA B; CIRIACI, NADIA; RAZORI, M VALERIA; BAROSSO, ISMAEL R.; BAROSSO, ISMAEL R.

Congreso; LXI Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica (SAIC); 2016

TLC is a bile salt that induces internalization of the canaliculartransporter /rp through adenylyl cyclase AC/2-A and 2+-dependent pathYays. There are a feY )protein coupled receptorsthat interact Yith bile salts. Among them, S24 in the only one,described up to noY, that is present in hepatocytes and potentiallyactivates adenylyl cyclase. +n consequence our aim Yas to evaluatethe role of this receptor in the impairment of /rp transportactivity induced by TLC./ethodology +solated rat hepatocyte couplets Yere preincubatedYith the antagonist of S24, ,TE ,TE, z/and then exposed to TLC . z/. Studies of additivity in theprotection of inhibitors Yere carried out by coadministration of,TE Yith 2+- inhibitor Yortmannina 9, n/ before exposureto TLC. Functional changes in Mrp2 under the treatmentsdescribed above Yere evaluated by assessing the canalicularvacuolar accumulation c8A of glutathione methylfluorescein)/F, a fluorescent /rp substrate derived from the additionof chloromethylfluorescein diacetate C/F&A, . z/./oreover, isolated hepatocytes Yere pretreated Yith ,TE andexposed to TLC. Then, cells Yere lysed and Yestern blot Yasperformed for analysis of A-T phosphorylation, an indicatorof A-T activation.4esults of control v SE/ n. Treatment Yith ,TEpartially prevented TLCinduced impairment in /rp activity TLCva, TLC,TE va,b. The preventive effects of 9 and,TE Yere not additive TLC va, TLC,TE va,b, TLC9va,b, TLC9,TE va,b suggesting that S24 and2+- share the same signaling pathYay. Activation of A-T inducedby TLC decreased in presence of ,TE TLC va, TLC,TEva,b. a p. vs control, b p. vs TLC.Conclusion The interaction of TLC Yith S24 Yould be oneof the first events in the signaling pathYay that leads to /rpactivity impairment, folloYed by a cascade activation of severalproteins including 2+-/A-T.