J Korean Rheum Assoc.  2007 Mar;14(1):23-30. 10.4078/jkra.2007.14.1.23.

The Effect of Estrogen on the DNA Methylation of B Cells in Patients with SLE

• Park MK
• Park SH
• Kwok SK
• Cho ML
• Kim HY

• KMID: 2202187
• DOI: http://doi.org/10.4078/jkra.2007.14.1.23

Abstract

OBJECTIVE
Epigenetics is an important, alternative mechanism of gene regulation that is independent of the nucleotide sequences of DNA. We investigated mRNA levels for DNA methyltransferase-1 (DNMT-1), and the effect of estrogen on the expression of DNMT-1 level in T cells and B cells from patients with systemic lupus erythematosus (SLE) and healthy subjects, and assessed the possible etiological role of DNA methylation in the pathogenesis of SLE.
METHODS
mRNA levels for DNMT-1 in CD4+ T cells and CD19+ B cells from 37 patients with SLE and 12 healthy controls were examined using RT-PCR. We used specific primer for DNMT-1 and beta actin, The effect of estrogen on the DNA methylation was measured by the mRNA level of DNMT-1 CD4+ T cells and CD19+ B cells treated with 100 nM of 17beta-estradiol for 72 hour.
RESULTS
The levels of DNMT-1 mRNA were significantly lower in CD4+ T cells and CD19+ B cells from SLE patients compared with healthy controls. We observed the suppression of the levels of DNMT-1 mRNA by stimulated with estrogen in patients with SLE patients, especially in CD19+B cells. DNA hypomethylation of B cells was tend to be correlated with the level of anti-ds DNA antibody without statistical significance (r=-0.43, p=0.3).
CONCLUSION
Our observations suggest that suppression of DNMT-1 by estrogen in B cells from patients with SLE might be related to the pathogenesis of SLE. Epigenetic studies may provide clues for developing new treatment strategies of SLE.

Keyword

Systemic lupus erythematosus; DNA methyltransferase-1; DNA methylation; Estrogen

MeSH Terms

Actins
B-Lymphocytes*
Base Sequence
DNA Methylation*
DNA*
Epigenomics
Estrogens*
Humans
Lupus Erythematosus, Systemic
RNA, Messenger
T-Lymphocytes
Actins
DNA
Estrogens
RNA, Messenger

Figure

• 

  Fig. 1. Structure and the exprssion of DNMT-1 mRNA level on CD4 T cell. (A) Structure of DNMT-1. Numbers indicate the nucleotide numbers. (B) The exprssion of DNMT-1 mRNA level on CD4 T cell of healthy controls and SLE patients, Freshly isolated CD4 T cell (2.5 X 10 cells/well) and cultured CD4 T cell (2.5 X 105 cells/well) for 72 hours in vitro from healthy controls and SLE patients were analyzed by RT-PCR with specific primer of DNMT-1 and β-actin as described in Materials and Methods. β-actin was used as an internal control. The exprssion of DNMT-1 mRNA level on CD4 T cell visualized on 1.5% agarose gel electrophoresis. Result are representative of two or three experiment.

• 

  Fig. 2. The exprssion of DNMT-1 mRNA level on CD4 T cells of healthy controls and SLE patients. Freshly isolated CD4 T cells (2.5 X 105 cells/well, left) and cultured CD4 T cells (2.5 X 105 cells/well, right) for 72 hours in vitro from healthy controls and SLE patients were analyzed by RT-PCR as described in Fig. 1. β-actin was used as an internal control. The number of patients and control included is given below the x-axis.

• 

  Fig. 3. The exprssion of DNMT-1 mRNA level on CD19 + B cell of healthy controls and SLE patients. Cultured CD19+ B cell (2.5 x 105 cells/well) for 72 hours in vitro from healthy controls and SLE patients were analyzed by RT-PCR with specific primer of DNMT-1 and β-actin as described in Materials and Methods. β-actin was used as an internal control. The number of patients and control included is given below the x-axis.

• 

  Fig. 4. The exprssion of DNMT-1 mRNA level by 17 β- estradiol on CD19 B cell and CD4 T cell of healthy controls and SLE patients. CD19+ B cells (2.5 x 105 cells/well, left) and CD4+ T cells (2.5 x 105 cells/well, right) from healthy controls and SLE patients treated with 100 nM of 17 β-estradiol for 72 hours. Cultured CD19+ B cell and CD4+ T cell were analyzed by RT-PCR with specific primer of DNMT-1 and β-actin as described in Materials and Methods. β-actin was used as an internal control. The number of patients and control included is given below the x-axis.

• 

  Fig. 5. Correlation between DNMT-1 levels of CD19 + B cell and serum anti-ds DNA antibody levels in SLE patients (n=8).

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