Lysine deacetylase inhibition prevents diabetes by chromatin-independent immunoregulation and ?-cell protection.

ABSTRACT: Type 1 diabetes is due to destruction of pancreatic ?-cells. Lysine deacetylase inhibitors (KDACi) protect ?-cells from inflammatory destruction in vitro and are promising immunomodulators. Here we demonstrate that the clinically well-tolerated KDACi vorinostat and givinostat revert diabetes in the nonobese diabetic (NOD) mouse model of type 1 diabetes and counteract inflammatory target cell damage by a mechanism of action consistent with transcription factor--rather than global chromatin--hyperacetylation. Weaning NOD mice received low doses of vorinostat and givinostat in their drinking water until 100-120 d of age. Diabetes incidence was reduced by 38% and 45%, respectively, there was a 15% increase in the percentage of islets without infiltration, and pancreatic insulin content increased by 200%. Vorinostat treatment increased the frequency of functional regulatory T-cell subsets and their transcription factors Gata3 and FoxP3 in parallel to a decrease in inflammatory dendritic cell subsets and their cytokines IL-6, IL-12, and TNF-?. KDACi also inhibited LPS-induced Cox-2 expression in peritoneal macrophages from C57BL/6 and NOD mice. In insulin-producing ?-cells, givinostat did not upregulate expression of the anti-inflammatory genes Socs1-3 or sirtuin-1 but reduced levels of IL-1? + IFN-?-induced proinflammatory Il1a, Il1b, Tnf?, Fas, Cxcl2, and reduced cytokine-induced ERK phosphorylation. Further, NF-?B genomic iNos promoter binding was reduced by 50%, and NF-?B-dependent mRNA expression was blocked. These effects were associated with NF-?B subunit p65 hyperacetylation. Taken together, these data provide a rationale for clinical trials of safety and efficacy of KDACi in patients with autoimmune disease such as type 1 diabetes.

SUBMITTER: Christensen DP 

PROVIDER: S-EPMC3903225 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature