INVOLVEMENT OF TUMOR NECROSIS FACTOR ALPHA (TNF)-INDUCED ROS SIGNALING IN THE IMPAIRMENT OF MRP2 FUNCTION

CIRIACI, NADIA; ANDERMATTEN, ROMINA B; BAROSSO, ISMAEL R.; RUIZ, M LAURA; SÁNCHEZ POZZI, ENRIQUE J

Mar del Plata

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

SAIC

Previous studies gave evidences that TNF could modulate /rp through endocytic internalization via activation of tYo pathYays one involving 2+-/AMt and the other /E-/E4-.)iven that T0Finduced reactive oxygen species 41S production activates 2+- and that oxidative stress induces internalizationof the bile salt export pump $sep, Ye decided to elucidate Yhether T0Finduced 41S signaling participates in the impairment of /rp function./ethodology +solated rat hepatocyte couplets Yere cotreated Yith T0F , pg/ml and antioxidants mannitol /an m/ and vitamin C 8itC z/ Yith or Yithout preincubation Yithi nhibitors of 2+- Yortmannin, 9 n/ or /E-/ 2& z/, upstream of E4-/. Then, functional changes in /rp activityYere evaluated by assessing the canalicular vacuolar accumulationc8A of glutathione methylfluorescein )/F, a fluorescent/rp substrate derived from chloromethylfluorescein diacetate, z/.2rimarycultured rat hepatocytes Yere exposed to 8itC andT0F. Then, activation of E4-/ and AMt 2+- effector Yas confirmedevaluating their phosphorylation status via Yestern blotting.4esults of Control, n Treatment Yith /an and 8itCpartially prevented T0Finduced impairment of canalicular accumulationof )/F T0F va T0F/an va,b T0F8itCva,b. 2rotection Yith 9 va,b shoYed addition Yith antioxidantT0F98itC va,b,c. +n contrast, preincubation of2& va,b did not add up Yith 8itC T0F2&8itC va,b,suggesting that /E-/E4- and 41S are in the same pathYay.Consistently, T0Finduced phosphorylation of E4- decreased inpresence 8itC T0F va T0F8itC vb indicating that41S production precedes E4- activation. a p. vs Control, bp. vs T0F, c p. vs T0F8itC and T0F9.Conclusion 41S are possible modulators of T0Fα-inducedimpairment of /rp function through a /E-/E4-dependentpathYay.