Hepatocyte apoptosis has been implicated in the progression of
nonalcoholic steatohepatitis. However, it is unclear whether the induction of
tumor necrosis factor (TNF)-α-mediated hepatocyte apoptosis in the simple
fatty liver triggers
liver fibrosis. To address this question, high-fat diet-fed mice were repeatedly administered D-
galactosamine, which increases the sensitivity of hepatocytes to TNF-α-mediated apoptosis. In mice treated with a high-fat diet plus D-
galactosamine, hepatocyte apoptosis and
liver fibrosis were induced, whereas both apoptosis and
fibrosis were inhibited in these mice following gut sterilization with antimicrobials or knockout of TNF-α. Furthermore,
liver fibrosis was diminished when hepatocyte apoptosis was inhibited by expressing a constitutively active inhibitor of nuclear factor κB
kinase subunit β. Thus, hepatocyte apoptosis induced by intestinal
dysbiosis or TNF-α up-regulation in the steatotic liver caused
fibrosis. Organ
fibrosis, including
liver fibrosis, involves the interaction of cyclic
adenosine monophosphate-response element-
binding protein-
binding protein (CBP) and β-
catenin. Here, hepatocyte-specific CBP-knockout mice showed reduced
liver fibrosis accompanied by hepatocyte apoptosis diminution; notably,
liver fibrosis was also decreased in mice in which CBP was specifically knocked out in
collagen-producing cells because the activation of these cells was now suppressed. Conclusion: TNF-α-mediated hepatocyte apoptosis induced
fibrosis in the steatotic liver, and inhibition of CBP/β-
catenin signaling attenuated the
liver fibrosis due to the reduction of hepatocyte apoptosis and suppression of the activation of
collagen-producing cells. Thus, targeting CBP/β-
catenin may represent a new therapeutic strategy for treating
fibrosis in
nonalcoholic steatohepatitis. (Hepatology Communications 2018;2:407-420).