Toll-like receptor 4 (TLR4) antagonist eritoran tetrasodium attenuates liver ischemia and reperfusion injury through inhibition of high-mobility group box protein B1 (HMGB1) signaling.
Toll-like receptor 4 (TLR4) is ubiquitously expressed on parenchymal and immune cells of the liver and is the most studied TLR responsible for the activation of proinflammatory signaling cascades in liver ischemia and reperfusion (I/R). Since pharmacological inhibition of TLR4 during the sterile inflammatory response of I/R has not been studied, we sought to determine whether eritoran, a TLR4 antagonist trialed in sepsis, could block hepatic TLR4-mediated inflammation and end organ damage. When C57BL/6 mice were pretreated with eritoran and subjected to warm liver I/R, there was significantly less hepatocellular injury compared to control counterparts. Additionally, we found that eritoran is protective in liver I/R through inhibition of high-mobility group box protein B1 (HMGB1)-mediated inflammatory signaling. When eritoran was administered in conjunction with recombinant HMGB1 during liver I/R, there was significantly less injury, suggesting that eritoran blocks the HMGB1-TLR4 interaction. Not only does eritoran attenuate TLR4-dependent HMGB1 release in vivo, but this TLR4 antagonist also dampened HMGB1's release from hypoxic hepatocytes in vitro and thereby weakened HMGB1's activation of innate immune cells. HMGB1 signaling through TLR4 makes an important contribution to the inflammatory response seen after liver I/R. This study demonstrates that novel blockade of HMGB1 by the TLR4 antagonist eritoran leads to the amelioration of liver injury.
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Kerry-Ann
KA
Mcdonald
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Hai
H
Huang
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Samer
S
Tohme
Center for Biologic Imaging, Department of Cell Biology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Patricia
P
Loughran
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Kimberly
K
Ferrero
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Timothy
T
Billiar
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Allan
A
Tsung
D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004187:Disaccharides / Q000494:pharmacology*; D024243:HMGB1 Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008107:Liver Diseases / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008810:Mice, Inbred C57BL; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects; D013403:Sugar Phosphates / Q000494:pharmacology*; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D004187:Disaccharides; D024243:HMGB1 Protein; C582808:HMGB1 protein, mouse; D015850:Interleukin-6; D008070:Lipopolysaccharides; D013403:Sugar Phosphates; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C577686:interleukin-6, mouse; C512420:eritoran