Androgen Effects on Alcohol-induced Liver Fibrosis Are Controlled by a Notch-dependent Epigenetic Switch

Background & Aims

Alcohol-associated liver disease (ALD) is a major cause of alcohol-related mortality. Sex is an important variable; however, the mechanism behind sex differences is not yet established.

Methods

Kdm5b flox/flox Kdm5c flox male mice were subjected to gonadectomy or sham surgery. Mice were fed a Western diet and 20% alcohol in the drinking water for 18 weeks. To induce knockout, mice received 2 × 10¹¹ genome copies of AAV8-CMV-Cre or AAV8-control. To test the role of Notch, mice were treated with 10 mg/kg of avagacestat for 4 weeks.

Results

We found that Kdm5b/Kdm5c knockout promoted alcohol-induced liver disease, whereas gonadectomy abolished this effect, suggesting that male sex hormones promote liver disease in the absence of KDM5 demethylases. In contrast, in the thioacetamide-induced fibrosis model, male sex hormones showed a protective effect regardless of genotype. In human liver disease samples, we found that androgen receptor expression positively correlated with fibrosis levels when KDM5B levels were low and negatively when KDM5B was high, suggesting that a KDM5B-dependent epigenetic state defines the androgen receptor role in liver fibrosis. Using isolated cells, we found that this difference was due to the differential effect of testosterone on hepatic stellate cell activation in the absence or presence of KDM5B/KDM5C. Moreover, this effect was mediated by KDM5-dependent suppression of Notch signaling. In KDM5-deficient mice, Notch3 and Jag1 gene expression was induced, facilitating testosterone-mediated induction of Notch signaling and stellate cell activation. Inhibiting Notch with avagacestat greatly reduced liver fibrosis and abolished the effect of Kdm5b/Kdm5c loss.

Conclusions

Male sex hormone signaling can promote or prevent alcohol-associated liver fibrosis depending on the KDM5-dependent epigenetic state.