Yuwen Su

Abnormal DNA methylation in CD4+ T cells from patients with systemic lupus erythematosus, systemic sclerosis, and dermatomyositis.

Objectives: T-cell DNA hypomethylation is thought to contribute to the development of systemic erythematosus lupus (SLE). However, it is unknown whether impaired T-cell DNA methylation occurs in other connective tissue diseases, such as systemic sclerosis (SSc) and dermatomyositis (DM). Methods: We quantified global methylation in CD4+ T cells from 12 healthy donors and patients with SLE, SSc, and DM (10 patients in each group). mRNA levels of DNA methyltransferases (DNMTs) and methyl-CpG-binding domain proteins (MBDs) were measured by reverse transcription polymerase chain reaction (RT-PCR). Results: CD4+ T-cell DNA from patients with SLE (both active and inactive) and SSc, but not DM, was significantly hypomethylated relative to controls. The average expression levels of DNMT1 and MBD4 mRNA were significantly lower whereas MBD2 and MeCP2 mRNA levels were significantly higher in the SLE group. DNMT1, MBD3, and MBD4 mRNA was significantly decreased in the SSc group, whereas MBD2 and MeCP2 mRNA was significantly higher in the DM group. The degree of global DNA hypomethylation correlated positively with the relative level of DNMT1 across SLE samples and MBD4 across the SSc samples. Conclusion: Reduced DNA methylation and abnormal expression of methylation-related genes in CD4+ T cells are associated with SLE and SSc.

Overexpression of the growth arrest and DNA damage–induced 45α gene contributes to autoimmunity by promoting DNA demethylation in lupus T cells

OBJECTIVE Demethylation of CD11a and CD70 regulatory regions in CD4+ T cells contributes to the development of autoreactivity and overstimulation of autoantibodies. Because growth arrest and DNA damage-induced 45alpha (GADD45alpha) reduces epigenetic silencing of genes by removing methylation marks, this study examined whether the gadd45A gene could contribute to autoimmunity by promoting DNA demethylation in T cells from patients with systemic lupus erythematosus (SLE). METHODS Levels of GADD45alpha, CD11a, and CD70 messenger RNA (mRNA) and protein were detected by real-time reverse transcription-polymerase chain reaction and Western blotting or flow cytometry. Global DNA methylation was evaluated using Methylamp global DNA methylation quantification kits. Detection of CD4+ T cell proliferation and autologous B cell IgG antibodies was performed using commercially available kits. CD11a and CD70 promoter methylation was determined with bisulfite sequencing. RESULTS Elevated gadd45A mRNA expression and global DNA hypomethylation were observed in CD4+ T cells from SLE patients. The levels of gadd45A mRNA were inversely proportional to the levels of DNA methylation. Positive correlations were found between gadd45A and CD11a/CD70 mRNA levels. Expression of gadd45A mRNA was increased in CD4+ T cells following ultraviolet B irradiation, and this was accompanied by increased levels of CD11a and CD70 mRNA. Moreover, increased expression of gadd45A, CD11a, and CD70 mRNA was accompanied by increased autoreactivity and excessive B cell stimulation in gadd45A-transfected CD4+ T cells. CD11a promoter methylation was also significantly reduced in transfected cells. Transfection of gadd45A small interfering RNA inhibited the autoreactivity of SLE CD4+ T cells and led to significant increases in the methylation levels of the CD11a and CD70 promoter regions. CONCLUSION These findings indicate that gadd45A may contribute to lupus-like autoimmunity by promoting DNA demethylation in SLE CD4+ T cells.

Whole-genome DNA methylation in skin lesions from patients with psoriasis vulgaris

Psoriasis, a chronic inflammatory skin disorder, is characterized by aberrant keratinocyte proliferation and differentiation in the epidermis. Although the pathogenesis of psoriasis is still incompletely understood, both genetic susceptibilities and environmental triggers are known to act as key players in its development. Several studies have suggested that DNA methylation is involved in the pathogenesis of psoriasis. However, the precise mechanisms underlying the regulation and maintenance of the methylome as well as their relationship with this disease remain poorly characterized. Herein, we used methylated DNA immunoprecipitation sequencing (MeDIP-Seq) to characterize whole-genome DNA methylation patterns in involved and uninvolved skin lesions from patients with psoriasis. The results of our MeDIP-Seq analyses identified differentially methylated regions (DMRs) covering almost the entire genome with sufficient depth and high resolution, showing that the number of hypermethylated DMRs was considerably higher than that of hypomethylated DMRs in involved psoriatic skin samples. Moreover, gene ontology analysis of MeDIP-Seq data showed that the aberrantly methylated genes belonged to several different ontological domains, such as the immune system, cell cycle and apoptosis. The results of the bisulfite-sequencing experiments for the genes PDCD5 and TIMP2 confirmed the methylation status identified by MeDIP-Seq, and the mRNA expression levels of these two genes were consistent with their DNA methylation profiles. To our knowledge, the present study constitutes the first report on MeDIP-Seq in psoriasis. The identification of whole-genome DNA methylation patterns associated with psoriasis provides new insight into the pathogenesis of this complex disease and represents a promising avenue through which to investigate novel therapeutic approaches.

RFX1 regulates CD70 and CD11a expression in lupus T cells by recruiting the histone methyltransferase SUV39H1

IntroductionRegulatory factor X-box 1 (RFX1) can interact with DNA methyltransferase 1 (DNMT1) and histone deacetylase 1 (HDAC1), and RFX1 down-regulation contributes to DNA hypomethylation and histone H3 hyperacetylation at the cluster of differentiation (CD) 11a and CD70 promoters in CD4+ T cells of patients with systemic lupus erythematosus (SLE). This leads to CD11a and CD70 overexpression, thereby triggering autoimmune responses. In order to provide more insight into the epigenetic mechanisms leading to the deregulation of autoimmune-related genes in SLE, we asked whether RFX1 is involved in regulating histone 3 lysine 9 (H3K9) tri-methylation at the CD11a and CD70 promoters in SLE CD4+ T cells.MethodsCD4+ T cell samples were isolated from 15 SLE patients and 15 healthy controls. H3K9 tri-methylation levels were measured by chromatin immunoprecipitation (ChIP) and real-time quantitative PCR. CD4+ T cells were transfected with plasmids using the Human T cell Nucleofector Kit. RFX1 and histone methyltransferase suppressor of variegation 3-9 (Drosophila) homolog 1 (SUV39H1) interaction was determined by co-immunoprecipation (co-IP) and Western blot and immunofluorescence staining. CD11a and CD70 mRNA levels were measured by real-time RT-PCR.ResultsH3K9 tri-methylation levels were significantly reduced within the CD11a and CD70 promoter regions in SLE CD4+ T cells. RFX1 co-immunoprecipitated with SUV39H1 at the CD11a and CD70 promoters in healthy control CD4+ T cells. Overexpressing or knocking-down RFX1 revealed that RFX1 expression correlated with H3K9 tri-methylation levels, as well as CD11a and CD70 expression levels in CD4+ T cells.ConclusionsRFX1 recruits SUV39H1 to the promoter regions of the CD11a and CD70 genes in CD4+ T cells, thereby regulating local H3K9 tri-methylation levels. These findings shed further light on the central role of RFX1 down-regulation in the epigenetic de-repression of auto-immune genes in SLE.

Up-regulation of microRNA-210 induces immune dysfunction via targeting FOXP3 in CD4+ T cells of psoriasis vulgaris

Psoriasis vulgaris (PV) is a chronic inflammatory and T cell-mediated autoimmune skin disease. An immune dysfunction that is manifested by abnormally activated T cells and defective regulatory T (Treg) cells may play an important role in the pathogenesis of PV. However, the precise mechanism of the immune dysfunction in PV patients still remains unclear. In this study, we found that miR-210 expression is increased significantly in CD4(+) T cells from patients with PV and confirmed that FOXP3 is a target gene of miR-210. We also found that overexpression of miR-210 inhibits FOXP3 expression and impairs the immunosuppressive functions of Treg cells in CD4(+) T cells from healthy controls. In contrast, inhibition of miR-210 increases FOXP3 expression and reverses the immune dysfunction in CD4(+) T cells from patients with PV. Our data demonstrates that increased miR-210 induces immune dysfunction via by FOXP3 in CD4(+) T cells from patients with PV.

Abnormal DNA methylation in T cells from patients with subacute cutaneous lupus erythematosus

Background  Impaired methylation of T‐cell DNA is thought to contribute to the development of systemic lupus erythematosus. However, it is unknown whether T‐cell hypomethylation is a factor in other, less severe, forms of lupus erythematosus such as subacute cutaneous lupus erythematosus (SCLE).

Abnormal histone modifications in PBMCs from patients with psoriasis vulgaris

Excessive keratinocyte proliferation is thought to be responsible for the formation and development of psoriasis vulgaris. Evidence indicates that epigenetic modifications are associated with aberrant gene expression, however, nothing is known about the status of histone modifications in psoriasis vulgaris. We investigated alterations in histone modifications in patients with psoriasis vulgaris. Global histone H3/H4 acetylation and H3K4/H3K27 methylation in peripheral blood mononuclear cells from 30 psoriatic patients and 20 healthy control subjects were quantified by the EpiQuik(TM) global histone H3/H4 acetylation and H3K4/H3K27 methylation assay kit. The mRNA levels of 12 members of 3 classes of chromatin modifier genes were measured by real-time quantitative polymerase chain reaction. Compared with normal controls, global histone H4 hypoacetylation was observed in PBMCs from psoriasis vulgaris patients. There was a negative correlation between the degree of histone H4 acetylation and disease activity in patients as measured by PASI. Global levels of H3 acetylation, H3K4/H3K27 methylation did not significantly differ between psoriatic patients and controls. mRNA levels of P300, CBP and SIRT1 were significantly reduced in PBMCs from patients with psoriasis vulgaris compared with healthy controls, while mRNA expression levels of HDAC1, SUV39H1 and EZH2 was significantly increased in psoriatic patients.We conclude that histone modifications are aberrant in the PBMCs of psoriasis vulgaris patients.

The Role of MicroRNAs in Autoimmune Diseases with Skin Involvement

MicroRNAs (miRNAs) are small non‐coding RNA molecules that negatively modulate gene expression by binding to the 3′ untranslated region (UTR) of target messenger RNAs (mRNAs), which leads to the degradation or translational repression of their target mRNAs. Previous research on miRNAs has revealed a new paradigm of gene regulations and pathways involved in the pathogenesis of autoimmune disorders and malignant diseases. The roles of miRNAs in cellular processes, including cell differentiation, proliferation, apoptosis and immune functions, are not clearly understood. MiRNAs are easily detected in a variety of sources, including tissues, serum and other body fluids, and this make them a good biological sample for pathogenic studies and disease biomarker development. This review encompasses the current understanding of the roles of miRNAs in autoimmunity and the cellular and molecular mechanisms of miRNAs in various autoimmune diseases (AIMDs). Specifically, we focus on the target genes of miRNAs and the biological processes associated with autoimmune diseases with skin involvement, including systemic lupus erythematosus, psoriasis, systemic sclerosis, Behcets disease and dermatomyositis. In addition, the diagnostic and therapeutic relevance of miRNAs that are involved in autoimmunity are elucidated to provide information for clinical implications.

E4BP4 overexpression: a protective mechanism in CD4+ T cells from SLE patients

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by various immunological abnormalities, including dysregulated activation of T and B lymphocytes, which trigger autoantibody production and immune-complex deposition. E4BP4, also known as NFIL3, has emerged as a major transcription factor that regulates the development and function of immune cells in a number of lineages. E4BP4 has been shown to regulate cytokines expression, and its synthesis is in turn controlled by various cytokines. To date, the roles of E4BP4 in immune dysregulation and autoimmune disorders are unclear. In this study, we demonstrated that E4BP4 expression is increased in CD4(+) T cells isolated from patients with active systemic lupus erythematosus (SLE), especially in patients treated with glucocorticoid (GC). Increased expression of E4BP4 inhibited the activation and self-reactivity of T cells stimulated by anti-CD3/CD28 antibodies. In contrast, the self-reactivity was enhanced in CD4(+) T cells from SLE patients following E4BP4 gene silencing and the production of autoantibody was increased in autologous B cells. We further demonstrated that E4BP4 directly regulated CD40L expression by binding to the promoter region and altering histone acetylation and methylation of the CD40L loci. Taken together, our data provide evidence that E4BP4 can inhibit CD40L expression through epigenetic modifications in the promoter region of CD40L, thus negatively regulating self-reactivity of SLE CD4(+) T cells. Furthermore, our data demonstrate that overexpression of E4BP4 initiates a protective mechanism in SLE CD4(+) T cells, which may be a promising target in the therapy for SLE.

Abnormal epigenetic modifications in peripheral blood mononuclear cells from patients with alopecia areata

Background  Alopecia areata (AA) is a hair loss disease caused by T‐cell‐mediated autoimmune reactions against anagen‐stage hair follicles. Although the exact aetiology is poorly understood, there is evidence to suggest that both genetic and environmental factors are involved in AA pathogenesis.