(P03-006-23) Chokeberry Effects on Gene Expression and Epigenetics of Interleukin-6

Objectives: Chokeberry, Aronia melanocarpa, used as a traditional food by some American Indian tribes has greater concentrations of anthocyanin compared to blueberries. Animal and human studies demonstrate that chokeberry juice extract (CBE) has cardioprotective, anti-diabetic, and anti-inflammatory properties. Palmitate (PA, 16:0) induces inflammatory gene expression. The objective of the study was to determine the effects of CBE and PA-induced interleukin-6 (IL-6) gene expression, IL-6 DNA methylation and histone H3 acetylation in human pre-adipocyte (HPA) cells.

Methods: HPA cells were pretreated with 2μM CBE for 3 hours. Cells were then treated with 0.17mM bovine serum albumin (BSA) for a control; 0.1mM PA; BSA in presence of 2μM CBE; and PA in presence of 2μM CBE. RT-qPCR analysis determined IL-6 mRNA expression normalized to 18s rRNA expression. The promoter region of IL-6 gene was tested for DNA methylation analysis. Western blot determined acetylation status of histone H3 on lysine residues K9, K14, and K18. One-way ANOVAs were run to determine significance of group differences.

Results: Treatment of cells with PA increased (p < 0.0001) IL-6 mRNA compared to control and CBE groups. While, treatment of cells with CBE decreased (p=.004) PA-induced IL-6 mRNA expression. IL-6 promoter DNA methylation increased at CpG site (-118) in CBE group compared to control (p=.026) and CBE+PA (p=.042) groups. There was no difference in histone H3 acetylation.

Conclusions: CBE induced IL-6 promoter methylation exerts a protective effect against inflammation induced by PA, as measured by IL-6 mRNA expression in HPA cells via regulating IL-6 promoter region methylation. Further studies are needed to determine whether increased dietary consumption of chokeberry reduces systemic inflammation in at risk populations including American Indians.

Funding Sources: USDA Agricultural Research Service Project #3062-51000-054-00D and NIH National Institute of General Medical Sciences #P20GM139759.