Cell Mol Gastroenterol Hepatol. 2021 Jun 04. pii: S2352-345X(21)00114-4. [Epub ahead of print]
Gaurav V Sarode,
Kari Neier,
Noreene M Shibata,
Yuanjun Shen,
Dmitry A Goncharov,
Elena A Goncharova,
Tagreed A Mazi,
Nikhil Joshi,
Matthew L Settles,
Janine M LaSalle,
Valentina Medici.
BACKGROUND & AIMS: The pathogenesis of Wilson disease (WD) involves hepatic and brain copper accumulation due to pathogenic variants affecting the ATP7B gene and downstream epigenetic and metabolic mechanisms. Prior methylome investigations in human WD liver and blood and in the Jackson Laboratory C3He-Atp7btx-j/J (tx-j) WD mouse model revealed an epigenetic signature of WD, including changes in the histone deacetylase HDAC5. We tested the hypothesis that histone acetylation is altered with respect to copper overload and aberrant DNA methylation in WD.
METHODS: We investigated class IIa histone deacetylases (HDAC4 and HDAC5) and H3K9/H3K27 histone acetylation in tx-j mouse livers compared to C3HeB/FeJ (C3H) control in response to 3 treatments: 60% kcal fat diet (HFD), D-penicillamine (PCA, copper chelator), and choline (methyl group donor). Experiments with copper-loaded HepG2 cells were conducted to validate in vivo studies.
RESULTS: In 9-week tx-j mice, HDAC5 levels significantly increased after 8 days of HFD compared to chow. In 24-week tx-j mice, HDAC4/5 levels were reduced 5- to 10-fold compared to C3H, likely through mechanisms involving HDAC phosphorylation. HDAC4/5 levels were affected by disease progression and accompanied by increased acetylation. PCA and choline partially restored HDAC4/5 and H3K9ac/H3K27ac to C3H levels. Integrated RNA and chromatin immunoprecipitation sequencing analyses revealed genes regulating energy metabolism and cellular stress/development which were, in turn, regulated by histone acetylation in tx-j mice compared to C3H, with Pparα and Pparγ among the most relevant targets.
CONCLUSION: These results suggest dietary modulation of class IIa HDAC4/5, and subsequent H3K9/H3K27 acetylation/deacetylation, can regulate gene expression in key metabolic pathways in the pathogenesis of WD.
Keywords: copper; histone deacetylase; liver; metabolism