Ten-eleven Translocation-2 Regulates DNA Hydroxymethylation Status and Psoriasiform Dermatitis Progression in Mice.

Epigenetics plays an important role in the development and progression of many diseases. There is increasing evidence for the importance of epigenetic modifications in the progression of psoriasis. The aim of this study was to examine the role and potential mechanism of action of 5-hydroxymethylcytosine (5-hmC) and ten-eleven translocation-2 (TET2) in psoriasiform dermatitis in mice. Immunohistochemical staining was performed on psoriasis patients and healthy controls. Topical application of imiquimod cream to the dorsal skin of mice was used to induce psoriasiform dermatitis. In comparison with healthy controls, 5-hmC was more extensive and intense in the skin lesions from psoriasis patients. TET2 and 5-hmC were highly expressed in imiquimod-induced psoriasiform skin lesions. Importantly, knockdown of TET2 expression in mice attenuated the psoriasiform phenotype and the expression levels of proinflammatory cytokines (interleukin-17A and -17F and interferon-?) and the chemokine CXCL1 in the lesional skin of mice. This is the first demonstration of a critical role for TET2 in psoriasiform dermatitis in a mouse model, and indicates that 5-hmC may serve as a potential biomarker of psoriasis.