title: A correlation study on the effects of DNMT1 on methylation levels in CD4(+) T cells of SLE patients.
abstract: OBJECTIVE
  To study the effect of DNMT1 on CD4(+) T cells in the peripheral blood of systemic lupus erythematosus (SLE) patients.
  
  
  METHODS
  To investigate the differential expression of DNMT1 in CD4(+) T cells of SLE patients and healthy individuals, a DNMT1 lentiviral plasmid (pLenti6.3/V5-DNMT1) and a control plasmid (pLenti6.3/V5-GW/LacZ) were constructed and transfected into CD4(+) T cells from the peripheral blood of SLE patients. The transcriptional and translational expression of DNMT1, global genomic DNA methylation, and the production of IgG antibody in the CD4(+) T cells in the peripheral blood of SLE patients were assessed using qPCR analysis, western blotting, flow cytometry, and ELISA, respectively.
  
  
  RESULTS
  The expression level of DNMT1 in SLE patients was significantly lower than that in normal humans. The expression of DNMT1 was found to be positively correlated with the methylation level of genomic DNA and negatively correlated with the IgG titration level. DNA sequencing results confirmed that the DNMT1 lentiviral plasmid was successfully constructed. After the CD4(+) T cells from the peripheral blood of SLE patients were transfected with the pLenti6.3/V5-DNMT1 plasmid, the transcription level of the DNMT1 gene was upregulated and abundance of DNMT1 protein significantly increased. Global genomic DNA methylation was enhanced, while the production of IgG antibody was reduced.
  
  
  CONCLUSIONS
  DNMT1 can inhibit the autoimmune response in SLE patients by reversing the abnormally low DNA methylation level in the CD4(+) T cells.
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Zhu
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Hai-Hong
authors.initials: HH
authors.lastname: Qin
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Jin-Ran
authors.initials: JR
authors.lastname: Lin
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Duo-Qin
authors.initials: DQ
authors.lastname: Wang
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Xiao-Qun
authors.initials: XQ
authors.lastname: Luo
authors.affiliation: Department of Dermatology, Huashan Hospital Fudan University Shanghai 200040, China.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Xu
keywords: CD4+ T cells; Lentivirus; SLE; methylation; pLenti6.3/V5-DNMT1