Epigenetic Dysregulation in the Pathogenesis of Systemic Lupus Erythematosus

The intersection of epigenetics and immune thrombocytopenia: new insights into disease mechanisms and treatments

Immune thrombocytopenia (ITP) is an autoimmune hematologic disorder that arises from an imbalance in immune responses, disrupting the delicate equilibrium of the immune system. An increasing body of research has indicated that immune-related genes hold promise as biomarkers for diagnosis and prognosis, with a particular focus on the roles of B and T cells in ITP pathogenesis. Despite these advancements, a deeper understanding of the underlying regulatory mechanisms governing these immune-related genes remains essential. This review aims to integrate the current body of evidence and provide further insights into the epigenetic regulation of immune pathways involved in ITP development. The problem statement section highlights the complexity of ITP and its intricate connections with immune pathways. It also compares the epigenetic differences between pediatric and adult ITP based on existing evidence. Decoding epigenetic processes could potentially open up new avenues for improving diagnostic methods and therapeutic strategies for ITP.

Regulation of B-cell function by miRNAs impacting Systemic lupus erythematosus progression

Systemic lupus erythematosus (SLE) is a complex autoimmune disease marked by abnormal B-cell proliferation and increased autoantibodies. miRNAs play a crucial role in regulating B-cell dysfunction and SLE pathology. miRNAs influence DNA methylation, B-cell activation, and gene expression, contributing to SLE pathogenesis. miRNAs impact B cells through key processes like proliferation, differentiation, tolerance, and apoptosis. miRNAs also exacerbate inflammation and immune responses by modulating Interleukin 4 (IL-4), IL-6, and interferon cytokines. Autophagy, a key degradation mechanism, is also regulated by specific miRNAs that impact SLE pathology. This article explores the role of multiple miRNAs in regulating B-cell development, proliferation, survival, and immune responses, influencing SLE pathogenesis. miRNAs like miR-23a, the miR-17 ∼ 92 family, and miR-125b/miR-221 affect B-cell development by regulating transcription factors, signaling pathways, and cell cycle genes. miRNAs such as miR-181a-5p and miR-23a-5p are differentially regulated across developmental stages, emphasizing their complex regulatory roles in B-cell biology. This article synthesizes miRNA-B cell interactions to offer new strategies and directions for SLE diagnosis and treatment.

Comparative Analysis of CXCR5 Circulating DNA Methylation Levels in Autoimmune Rheumatic Diseases

OBJECTIVE

To assess CXC chemokine receptor 5 (CXCR5) circulating DNA methylation differences in autoimmune rheumatic diseases and their relation with clinical features.

METHODS

Targeted methylation sequencing was performed using peripheral blood from 164 rheumatoid arthritis (RA), 30 systemic lupus erythematosus (SLE), 30 ankylosing spondylitis (AS), 30 psoriatic arthritis (PsA), 24 Sjögren's syndrome (SS) patients, and 30 healthy controls (HC).

RESULTS

Significant differences in CXCR5 cg19599951 methylation were found between RA and HC, as well as AS and SLE. RA patients exhibited higher methylation than HC and AS (p < 0.01) but lower than SLE (p < 0.05). SLE patients showed higher methylation compared to HC, AS, and PsA (p < 0.001, 0.01, and 0.05, respectively). No significant differences were found in patients with SS compared to other autoimmune diseases and HC. Methylation at cg19599951_103 (r = 0.17, p < 0.05) and cg19599951_209 (r = 0.22, p < 0.01), along with the CC haplotype (r = 0.21, p < 0.01), showed significant positive correlations with erythrocyte sedimentation rate (ESR), while the CT (r = -0.27, p < 0.001) and TT haplotypes (r = -0.19, p < 0.05) were negatively correlated. For C-reactive protein (CRP), methylation at cg19599951_103 (r = 0.29, p < 0.001) and cg19599951_209 (r = 0.33, p < 0.0001), and the CC haplotype (r = 0.34, p < 0.0001) was positively correlated, whereas the CT (r = -0.36, p < 0.0001) and TT (r = -0.30, p < 0.0001) haplotypes were negatively correlated. Significant negative correlations were observed between the CT haplotype and rheumatoid factor (r = -0.25, p < 0.01), and anti-citrullinated protein antibody (r = -0.20, p < 0.05). No significant correlations were found in patients with SLE, AS, and SS. Receiver operating characteristic analysis showed CXCR5 methylation could classify patients with RA versus those with AS (AUC: 0.624-0.967).

CONCLUSION

Differential circulating CXCR5 methylation levels were observed in autoimmune rheumatic diseases, which correlated with inflammatory mediators in RA and may serve as potential biomarkers for RA diagnosis.

Systemic lupus erythematosus: pathogenesis and targeted therapy

Systemic lupus erythematosus (SLE) is a multifaceted autoimmune disorder characterized by dysregulated immune responses and autoantibody production, which affects multiple organs and varies in clinical presentation and disease severity. The development of SLE is intricate, encompassing dysregulation within the immune system, a collapse of immunological tolerance, genetic susceptibilities to the disease, and a variety of environmental factors that can act as triggers. This review provides a comprehensive discussion of the pathogenesis and treatment strategies of SLE and focuses on the progress and status of traditional and emerging treatment strategies for SLE. Traditional treatment strategies for SLE have mainly employed non-specific approaches, including cytotoxic and immunosuppressive drugs, antimalarials, glucocorticoids, and NSAIDs. These strategies are effective in mitigating the effects of the disease, but they are not a complete cure and are often accompanied by adverse reactions. Emerging targeted therapeutic drugs, on the other hand, aim to control and treat SLE by targeting B and T cells, inhibiting their activation and function, as well as the abnormal activation of the immune system. A deeper understanding of the pathogenesis of SLE and the exploration of new targeted treatment strategies are essential to advance the treatment of this complex autoimmune disease.

Methylation levels of the IL10 gene in peripheral blood are related to the intractability of Graves' disease

The prognosis of autoimmune thyroid diseases (AITDs), including Hashimoto's disease (HD) and Graves' disease (GD), is difficult to predict. DNA methylation regulates gene expression of immune mediating factors. Interleukin (IL)-10 is a Th2 cytokine that downregulates inflammatory cytokines produced by Th1 cells. To clarify the role of methylation of the IL10 gene in the prognosis of AITD, we evaluated the methylation levels of two CpG sites in the IL10 promoter using pyrosequencing. The methylation levels of the -185 CpG site of the IL10 gene were related to age and GD intractability in GD patients. Furthermore, the C carrier of the IL10-592 A/C polymorphism was related to low methylation levels of the -185 CpG site. The methylation levels of the IL10-185 CpG site of the IL10 gene were related to the intractability of GD and were lower in individuals with the C allele of the IL10-592 A/C polymorphism.

Regulation of cytokine and chemokine expression by histone lysine methyltransferase MLL1 in rheumatoid arthritis synovial fibroblasts

Histone lysine methylation is thought to play a role in the pathogenesis of rheumatoid arthritis (RA). We previously reported aberrant expression of the gene encoding mixed-lineage leukemia 1 (MLL1), which catalyzes methylation of histone H3 lysine 4 (H3K4), in RA synovial fibroblasts (SFs). The aim of this study was to elucidate the involvement of MLL1 in the activated phenotype of RASFs. SFs were isolated from synovial tissues obtained from patients with RA or osteoarthritis (OA) during total knee joint replacement. MLL1 mRNA and protein levels were determined after stimulation with tumor necrosis factor α (TNFα). We also examined changes in trimethylation of H3K4 (H3K4me3) levels in the promoters of RA-associated genes (matrix-degrading enzymes, cytokines, and chemokines) and the mRNA levels upon small interfering RNA-mediated depletion of MLL1 in RASFs. We then determined the levels of H3K4me3 and mRNAs following treatment with the WD repeat domain 5 (WDR5)/MLL1 inhibitor MM-102. H3K4me3 levels in the gene promoters were also compared between RASFs and OASFs. After TNFα stimulation, MLL1 mRNA and protein levels were higher in RASFs than OASFs. Silencing of MLL1 significantly reduced H3K4me3 levels in the promoters of several cytokine (interleukin-6 [IL-6], IL-15) and chemokine (C-C motif chemokine ligand 2 [CCL2], CCL5, C-X-C motif chemokine ligand 9 [CXCL9], CXCL10, CXCL11, and C-X3-C motif chemokine ligand 1 [CX3CL1]) genes in RASFs. Correspondingly, the mRNA levels of these genes were significantly decreased. MM-102 significantly reduced the promoter H3K4me3 and mRNA levels of the CCL5, CXCL9, CXCL10, and CXCL11 genes in RASFs. In addition, H3K4me3 levels in the promoters of the IL-6, IL-15, CCL2, CCL5, CXCL9, CXCL10, CXCL11, and CX3CL1 genes were significantly higher in RASFs than OASFs. Our findings suggest that MLL1 regulates the expression of particular cytokines and chemokines in RASFs and is associated with the pathogenesis of RA. These results could lead to new therapies for RA.