Further investigation regarding the underlying epigenetic mechanisms discovered that hyperglycemia increased acetyl-H3K9, H4K20me3, and NF-kB-p65 at the promoter and enhancer regions of retinal Sod2, and upregulated protein and gene expression of SUV420h2, one of the primary enzymes for the trimethylation of H4K20. Here, NFKB1 is linked to Hyperglycemia.