title: Tauroursodeoxycholic acid affects PPARγ and TLR4 in Steatotic liver transplantation.
abstract: Numerous steatotic livers are discarded for transplantation because of their poor tolerance to ischemia-reperfusion (I/R). We examined whether tauroursodeoxycholic acid (TUDCA), a known inhibitor of endoplasmic reticulum (ER) stress, protects steatotic and nonsteatotic liver grafts preserved during 6 h in University of Wisconsin (UW) solution and transplanted. The protective mechanisms of TUDCA were also examined. Neither unfolded protein response (UPR) induction nor ER stress was evidenced in steatotic and nonsteatotic liver grafts after 6 h in UW preservation solution. TUDCA only protected steatotic livers grafts and did so through a mechanism independent of ER stress. It reduced proliferator-activated receptor-γ (PPARγ) and damage. When PPARγ was activated, TUDCA did not reduce damage. TUDCA, which inhibited PPARγ, and the PPARγ antagonist treatment up-regulated toll-like receptor 4 (TLR4), specifically the TIR domain-containing adaptor inducing IFNβ (TRIF) pathway. TLR4 agonist treatment reduced damage in steatotic liver grafts. When TLR4 action was inhibited, PPARγ antagonists did not protect steatotic liver grafts. In conclusion, TUDCA reduced PPARγ and this in turn up-regulated the TLR4 pathway, thus protecting steatotic liver grafts. TLR4 activating-based strategies could reduce the inherent risk of steatotic liver failure after transplantation.
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBPAS), Barcelona, Spain.
authors.forename: M B
authors.initials: MB
authors.lastname: Jiménez-Castro
authors.forename: M
authors.initials: M
authors.lastname: Elias-Miro
authors.forename: M
authors.initials: M
authors.lastname: Mendes-Braz
authors.forename: A
authors.initials: A
authors.lastname: Lemoine
authors.forename: A
authors.initials: A
authors.lastname: Rimola
authors.forename: J
authors.initials: J
authors.lastname: Rodés
authors.forename: A
authors.initials: A
authors.lastname: Casillas-Ramírez
authors.forename: C
authors.initials: C
authors.lastname: Peralta
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D015153:Blotting, Western; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D005234:Fatty Liver / Q000378:metabolism / Q000517:prevention & control*; D016031:Liver Transplantation; D008297:Male; D009765:Obesity; D009926:Organ Preservation; D047495:PPAR gamma / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011924:Rats, Zucker; D015427:Reperfusion Injury / Q000517:prevention & control*; D013655:Taurochenodeoxycholic Acid / Q000494:pharmacology*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D014185:Transplantation, Isogeneic; D056811:Unfolded Protein Response / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D047495:PPAR gamma; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D013655:Taurochenodeoxycholic Acid; C031655:ursodoxicoltaurine