ABSTRACT
DNA methylation and hydroxymethylation are the most common epigenetic modifications associated with the cell cycle and the inflammatory response. The present study aimed to investigate the role of 5hydroxymethylcytosine (5hmC) and teneleven translocation2 (TET2) in keratinocytes. Following TET2 knockdown, dot blot analysis was performed to assess the levels of 5hmC in keratinocytes, using HaCaT cells. Subsequently, the viability and cell cycle of HaCaT cells were assessed by MTT, Cell Counting Kit8 assay and flow cytometric assays. Cyclindependent kinase inhibitor 2A and proinflammatory cytokine protein and mRNA expression levels were also detected. The present results suggested that TET2 may play an important role in regulating cellular proliferation by mediating DNA hydroxymethylation in HaCaT cells. In addition, TET2 knockdown decreased the production of proinflammatory cytokines, including lipocalin 2, S100 calcium binding protein A7, matrix metallopeptidase 9, CXC motif chemokine ligand 1, interferon regulatory factor 7 and interleukin7 receptor. The present study suggested that TET2 regulated cell viability, apoptosis and the expression of inflammatory mediators in keratinocytes. Collectively, the results indicated that TET2 knockdown may relieve inflammatory responses in the skin.
Subject(s)
DNA Methylation/genetics , DNA-Binding Proteins/metabolism , Inflammation/genetics , Keratinocytes/metabolism , Keratinocytes/pathology , Proto-Oncogene Proteins/metabolism , 5-Methylcytosine/analogs & derivatives , 5-Methylcytosine/metabolism , Apoptosis/genetics , Cell Cycle/genetics , Cell Proliferation/genetics , Cell Survival/genetics , Cyclin-Dependent Kinase Inhibitor p16/metabolism , Cytokines/genetics , Cytokines/metabolism , Dioxygenases , HaCaT Cells , Humans , Inflammation Mediators/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolismABSTRACT
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.
