Inhibition of DNA methylation with zebularine alters lipopolysaccharide-induced neuroinflammation in mice

Inhibitors of DNA methyltransferases (DNMTs), the enzymes that catalyze DNA methylation, alter DNA methylation globally in the brain and at individual neural plasticity-associated genes. This suggests that DNA methylation is dynamically regulated in the brain, but how DNMT inhibitors centrally influence lipopolysaccharide (LPS)-induced neuroinflammation is not known. Specifically, we sought to determine if zebularine would alter DNA methylation of the Il1b promoter as well as expression of inflammatory genes in the hippocampus and microglia. Adult 3–6 month-old C57BL/6J mice were implanted with an intracerebroventricular (ICV) cannula, and after 7 days of recovery were injected ICV with saline or the DNMT inhibitor zebularine (300 ng/ul). LPS (10 ng/ul) or saline was injected ICV 30 min later. Using bisulfite pyrosequencing, novel findings indicate that ICV zebularine led to decreased DNA methylation of one of the CpG sites near the Il1b proximal promoter alone or in combination with LPS ( p p  > 0.05). Ongoing work will assess treatment effects 4 h post-injection when inflammation is expected to be maximal. Taken together, these data suggest that modulation of DNA methylation with a DNMT inhibitor in the brain can affect molecular mechanisms of neuroinflammation. Supported by NIH AG016710.