title: MicroRNA-29b contributes to DNA hypomethylation of CD4+ T cells in systemic lupus erythematosus by indirectly targeting DNA methyltransferase 1.
abstract: BACKGROUND
  The mechanism of DNA hypomethylation in systemic lupus erythematosus (SLE) has not been fully elucidated. Recent studies showed that miR-29b could regulate DNA methylation by targeting the DNA methylation machinery. However, the role of miR-29b in T cell aberrant DNA hypomethylation of SLE still remains unclear.
  
  
  OBJECTIVE
  In this study, we asked whether miR-29b regulate DNA methylation in lupus CD4+ T cells.
  
  
  METHODS
  The miR-29b expression was analyzed by quantitative polymerase chain reaction (qPCR). Sp1, DNMT1, CD11a and CD70 mRNA and protein levels were determined by qPCR, Western-blotting and flow cytometry, respectively. The global DNA methylation levels were evaluated by the Methyflash™ DNA Methylation Quantification Kit. CD11a and CD70 promoter methyaltion levels were detected by bisulfate modification and methylation-sensitive high resolution melting analysis.
  
  
  RESULTS
  In SLE patients, the miR-29b levels were up-regulated as compared to healthy donors and its degree of overexpression was negatively correlated with sp1 and DNMT1 protein levels, respectively. Overexpression of miR-29b resulted in significant reduction of sp1 and DNMT1 expression. Further analysis demonstrated that overexpression of miR-29b in CD4+ T cells from healthy donors led to the DNA hypomethylation and up-regulation of genes encoding CD11a and CD70, and inhibition of miR-29b expression in CD4+ T cells from patients with lupus caused reverse effects.
  
  
  CONCLUSIONS
  Our study suggests that miR-29b negatively regulates DNMT1 expression by targeting sp1 in T cells. The overexpression of miR-29b contributes to the reduction of DNMT1 levels and thereby DNA hypomethylation in SLE. This finding provides potential novel strategies for therapeutic interventions.
authors.affiliation: Department of Dermatology, Huashan Hospital, Fudan University, Shanghai 200040, China.
authors.forename: Haihong
authors.initials: H
authors.lastname: Qin
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Zhu
authors.forename: Jun
authors.initials: J
authors.lastname: Liang
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wu
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Yang
authors.forename: Shangshang
authors.initials: S
authors.lastname: Wang
authors.forename: Weimin
authors.initials: W
authors.lastname: Shi
authors.forename: Jinhua
authors.initials: J
authors.lastname: Xu
mesh_terms: D000328:Adult; D040881:CD11a Antigen / Q000235:genetics; D053282:CD27 Ligand / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000201:enzymology*; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation; D005260:Female; D015870:Gene Expression; D006801:Humans; D019169:Jurkat Cells; D008180:Lupus Erythematosus, Systemic / Q000201:enzymology* / Q000235:genetics; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D061251:Primary Cell Culture; D016329:Sp1 Transcription Factor / Q000378:metabolism; D018709:Statistics, Nonparametric; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D040881:CD11a Antigen; D053282:CD27 Ligand; C532045:MIRN29a microRNA, human; D035683:MicroRNAs; D016329:Sp1 Transcription Factor; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human