TY - JOUR
T1 - TRIF Differentially Regulates Hepatic Steatosis and Inflammation/Fibrosis in Mice
AU - Yang, Ling
AU - Miura, Kouichi
AU - Zhang, Bi
AU - Matsushita, Hiroshi
AU - Yang, Yoon Mee
AU - Liang, Shuang
AU - Song, Jingyi
AU - Roh, Yoon Seok
AU - Seki, Ekihiro
N1 - Funding Information:
Funding This study was supported by National Institutes of Health grants R01AA02172, R01DK085252, and P42 ES010337 (E.S.); the American Liver Foundation Irwin M. Arias, MD, Postdoctoral Research Fellowship (Y.M.Y.); the American Liver Foundation Congressman John Joseph Moakley Postdoctoral Research Fellowship (Y.S.R.); and National Natural Science Foundation of China grants 81370550, 81570530, and 30500658 (L.Y.).
Publisher Copyright:
© 2017 The Authors
PY - 2017/5
Y1 - 2017/5
N2 - Background & Aims Toll-like receptor 4 (TLR4) signaling is activated through 2 adaptor proteins: MyD88 and TIR-domain containing adaptor-inducing interferon-β (TRIF). TLR4 and MyD88 are crucial in nonalcoholic steatohepatitis (NASH) and fibrosis. However, the role of TRIF in TLR4-mediated NASH and fibrosis has been elusive. This study investigated the differential roles of TRIF in hepatic steatosis and inflammation/fibrosis. Methods A choline-deficient amino acid defined (CDAA) diet was used for the mouse NASH model. On this diet, the mice develop hepatic steatosis, inflammation, and fibrosis. TLR4 wild-type and TLR4-/- bone marrow chimeric mice and TRIF-/- mice were fed CDAA or a control diet for 22 weeks. Hepatic steatosis, inflammation, and fibrosis were examined. Results In the CDAA diet–induced NASH, the mice with wild-type bone marrow had higher alanine aminotransferase and hepatic tumor necrosis factor levels than the mice with TLR4-/- bone marrow. The nonalcoholic fatty liver disease activity score showed that both wild-type and TLR4-/- bone marrow chimeras had reduced hepatic steatosis, and that both types of chimeras had similar levels of inflammation and hepatocyte ballooning to whole-body wild-type mice. Notably, wild-type recipients showed more liver fibrosis than TLR4-/- recipients. Although TRIF-/- mice showed reduced hepatic steatosis, these mice showed more liver injury, inflammation, and fibrosis than wild-type mice. TRIF-/- stellate cells and hepatocytes produced more C-X-C motif chemokine ligand 1 (CXCL1) and C-C motif chemokine ligand than wild-type cells in response to lipopolysaccharide. Consistently, TRIF-/- mice showed increased CXCL1 and CCL3 expression along with neutrophil and macrophage infiltration, which promotes liver inflammation and injury. Conclusions In TLR4-mediated NASH, different liver cells have distinct roles in hepatic steatosis, inflammation, and fibrosis. TRIF promotes hepatic steatosis but it inhibits injury, inflammation, and fibrosis.
AB - Background & Aims Toll-like receptor 4 (TLR4) signaling is activated through 2 adaptor proteins: MyD88 and TIR-domain containing adaptor-inducing interferon-β (TRIF). TLR4 and MyD88 are crucial in nonalcoholic steatohepatitis (NASH) and fibrosis. However, the role of TRIF in TLR4-mediated NASH and fibrosis has been elusive. This study investigated the differential roles of TRIF in hepatic steatosis and inflammation/fibrosis. Methods A choline-deficient amino acid defined (CDAA) diet was used for the mouse NASH model. On this diet, the mice develop hepatic steatosis, inflammation, and fibrosis. TLR4 wild-type and TLR4-/- bone marrow chimeric mice and TRIF-/- mice were fed CDAA or a control diet for 22 weeks. Hepatic steatosis, inflammation, and fibrosis were examined. Results In the CDAA diet–induced NASH, the mice with wild-type bone marrow had higher alanine aminotransferase and hepatic tumor necrosis factor levels than the mice with TLR4-/- bone marrow. The nonalcoholic fatty liver disease activity score showed that both wild-type and TLR4-/- bone marrow chimeras had reduced hepatic steatosis, and that both types of chimeras had similar levels of inflammation and hepatocyte ballooning to whole-body wild-type mice. Notably, wild-type recipients showed more liver fibrosis than TLR4-/- recipients. Although TRIF-/- mice showed reduced hepatic steatosis, these mice showed more liver injury, inflammation, and fibrosis than wild-type mice. TRIF-/- stellate cells and hepatocytes produced more C-X-C motif chemokine ligand 1 (CXCL1) and C-C motif chemokine ligand than wild-type cells in response to lipopolysaccharide. Consistently, TRIF-/- mice showed increased CXCL1 and CCL3 expression along with neutrophil and macrophage infiltration, which promotes liver inflammation and injury. Conclusions In TLR4-mediated NASH, different liver cells have distinct roles in hepatic steatosis, inflammation, and fibrosis. TRIF promotes hepatic steatosis but it inhibits injury, inflammation, and fibrosis.
KW - Hepatocyte Apoptosis
KW - LPS
KW - Neutrophils
KW - TLR4
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U2 - 10.1016/j.jcmgh.2016.12.004
DO - 10.1016/j.jcmgh.2016.12.004
M3 - Article
C2 - 28462384
AN - SCOPUS:85018319793
SN - 2352-345X
VL - 3
SP - 469
EP - 483
JO - CMGH
JF - CMGH
IS - 3
ER -