Ankylosing Spondylitis Patients Display Aberrant ERAP1 Gene DNA Methylation and Expression

Functional significance of DNA methylation: epigenetic insights into Sjögren's syndrome

Sjögren's syndrome (SjS) is a systemic, highly diverse, and chronic autoimmune disease with a significant global prevalence. It is a complex condition that requires careful management and monitoring. Recent research indicates that epigenetic mechanisms contribute to the pathophysiology of SjS by modulating gene expression and genome stability. DNA methylation, a form of epigenetic modification, is the fundamental mechanism that modifies the expression of various genes by modifying the transcriptional availability of regulatory regions within the genome. In general, adding a methyl group to DNA is linked with the inhibition of genes because it changes the chromatin structure. DNA methylation changes the fate of multiple immune cells, such as it leads to the transition of naïve lymphocytes to effector lymphocytes. A lack of central epigenetic enzymes frequently results in abnormal immune activation. Alterations in epigenetic modifications within immune cells or salivary gland epithelial cells are frequently detected during the pathogenesis of SjS, representing a robust association with autoimmune responses. The analysis of genome methylation is a beneficial tool for establishing connections between epigenetic changes within different cell types and their association with SjS. In various studies related to SjS, most differentially methylated regions are in the human leukocyte antigen (HLA) locus. Notably, the demethylation of various sites in the genome is often observed in SjS patients. The most strongly linked differentially methylated regions in SjS patients are found within genes regulated by type I interferon. This demethylation process is partly related to B-cell infiltration and disease progression. In addition, DNA demethylation of the runt-related transcription factor (RUNX1) gene, lymphotoxin-α (LTA), and myxovirus resistance protein A (MxA) is associated with SjS. It may assist the early diagnosis of SjS by serving as a potential biomarker. Therefore, this review offers a detailed insight into the function of DNA methylation in SjS and helps researchers to identify potential biomarkers in diagnosis, prognosis, and therapeutic targets.

DNA methylation and expression of LGR6 gene in ankylosing spondylitis: A case-control study

OBJECTIVE

The objectives of the present research were to ascertain the relationship of Leucine-Rich Repeat-Containing G-Protein Coupled Receptors 6 (LGR6) methylation and transcript levels with ankylosing spondylitis (AS).

METHODS

Targeted bisulfite sequencing was applied to analyze LGR6 DNA methylation in 81 AS cases and 81 controls. Besides, the LGR6 transcription level of peripheral blood mononuclear cells (PBMCs) from 70 AS cases and 64 controls was measured utilizing quantitative real-time transcription-polymerase chain reaction (qRT-PCR).

RESULTS

The study detected the methylation levels of 43 sites in two CpG (cytosine-guanine dinucleotide) islands of LGR6 and found that LGR6 were significantly hypomethylated in AS patients (LGR6_1: P = 0.002; LGR6_2: P < 0.001). LGR6 transcript level was obviously reduced in AS (P = 0.001) and was positively related to DNA methylation level (CpG-1: P = 0.010; CpG-2: P = 0.007). Besides, the Receiver operating characteristic curve (ROC) exhibited good diagnostic performance of LGR6 methylation level (AUC = 0.676, 95% CI = 0.594-0.758, P < 0.001). Further subgroup analysis revealed that gender may affect the LGR6_1 methylation pattern.

CONCLUSION

The present study revealed that LGR6 DNA methylation dysregulation may be involved in the pathogenesis of AS from an epigenetic perspective for the first time, with the aim of providing new directions for biomarker identification and treatment development for AS patients.

PRICKLE1 gene methylation and abnormal transcription in Chinese patients with ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis (AS) is a common inflammatory arthritis without a reliable biomarker. The role of methylation and mRNA expression of PRICKLE1 promoter in the pathogenesis of ankylosing spondylitis remains unclear.

METHODS

A two-stage case-control design was used to detect the characteristics of methyl group and transcriptome of PRICKLE1 gene in Ankylosing spondylitis. The methylation degree of PRICKLE1 gene promoter region was tested by phosphate-sequencing, and further analyzed whether there was significant difference in methylation level of PRICKLE1 gene. The expression levels of PRICKLE1 mRNA in 50 AS patients and 50 healthy controls were detected by real-time quantitative PCR (RT-qPCR).

RESULTS

Compared with healthy control group, the intensity of methylation in 4 ponds of PRICKLE1 in patients with Ankylosing spondylitis was low, and the mRNA levels were overexpressed (P = 0.017). ROC results showed that the sensitivity of PRICKLE1 was 68.67% and specificity was 71.43%.

CONCLUSION

There is a significant change in the concentration of serum PRICKLE1 mRNA​in patients with Ankylosing spondylitis, and the degree of gene methylation is significantly reduced, suggesting that PRICKLE1 gene maybe involved in the pathogenesis of Ankylosing spondylitis, which may be useful for predicting the occurrence of AS and finding new early screening indicators.

DNA methylation of DKK-1 may correlate with pathological bone formation in ankylosing spondylitis

OBJECTIVE

To investigate DNA methylation (DNAm) status of dickkopf-associated protein 1 (DKK-1) in ossified hip capsule synovium and serum among patients with ankylosing spondylitis (AS).

METHODS

Western blot was applied to detect the level of DKK-1 protein expression in hip joint capsule tissues from four patients with AS as well as four patients with femoral neck fracture (FNF) caused by trauma as control. DKK-1 gene promoter methylation (GPM) was examined by methylation-specific polymerase chain reaction. Reverse transcription-polymerase chain reaction was performed to examine the messenger RNA (mRNA) levels of DKK-1, β-catenin, and Wnt3a in both tissue and serum. The DNAm status of serum DKK-1 was measured among 36 patients with AS and syndesmophytes (AS + syndesmophytes group), 40 patients with AS but no syndesmophyte (AS group), and 42 healthy individuals (control group). Also, the serum levels of DKK-1 were measured by enzyme-linked immunosorbent assay. The modified New York criteria (mNYC) together with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) were adopted to examine the radiographic progression of AS. The receiver operating characteristic (ROC) curve was applied to investigate the diagnostic value of the methylation rate of DKK-1 with regard to radiographic progression.

RESULTS

The expressions of DKK-1 protein and mRNA in hip joint capsule tissues of AS patients were significantly lower, while DKK-1 GPM rate, β-catenin mRNA, and Wnt3a mRNA were markedly higher when compared with FNF group. For serum samples, the DKK-1 methylation rate was significantly higher in AS+ syndesmophytes group in contrast to AS group and healthy controls. Serum levels of DKK-1 protein and mRNA in AS with syndesmophytes group were markedly decreased, while β-catenin mRNA and Wnt3a mRNA expressions were significantly increased than AS with no syndesmophyte group and the healthy control group. AS patients in Grade 4 showed a significantly higher serum DKK-1 GPM rate than those in Grade 3 based on mNYC. Serum DKK-1 GPM level was markedly and positively correlated with mSASSS. Serum levels of DKK-1 in AS+ syndesmophytes group were markedly lower compared with AS but no syndesmophyte group and healthy controls. ROC curve analysis indicated that serum DKK-1 methylation rate serves as a decent indicator for AS radiographic progression.

CONCLUSION

DNAm of DKK-1 may correlate with pathological bone formation in AS, which may provide new strategies for the treatment of AS abnormal bone formation.

DNA methylation and transcriptome signatures of the PDCD1 gene in ankylosing spondylitis

Ankylosing spondylitis (AS) is an autoimmune-related inflammatory arthritis. The association between the DNA methylation and mRNA expression of PDCD1 gene with the susceptibility to AS remains unclear. In this case-control study, the methylation level of PDCD1 promoter was detected in 80 AS patients and 80 healthy controls by MethylTarget method. The transcriptional level of PDCD1 gene was measured in 47 AS patients and 47 healthy controls by real-time quantitative PCR. Finally, 17 methylation sites mapped to one CpG island were detected. Compared to healthy controls, the promoter of PDCD1 was hypermethylated (p < 0.001) and the mRNA expression was downregulated (p < 0.001) in AS patients. Significantly negative correlation was identified between the DNA methylation and mRNA expression of PDCD1 gene (r_s = -0.470, p < 0.001). The receiver operating characteristic (ROC) results showed that PDCD1 island had a sensitivity of 61.3% and a specificity of 82.5%, and PDCD1 mRNA had a sensitivity of 87.2% and a specificity of 89.0%. The methylation level of PDCD1 was positively correlated with the ESR, CRP and ASDAS of AS, and was not affected by HLA-B27 status, gender or medicine intake.

DNA methylation and transcriptional profiles of IRF5 gene in ankylosing spondylitis: A case-control study

BACKGROUND

Interferon regulatory factor 5 (IRF5) plays an important role in the inflammation and immune responses, but its association with ankylosing spondylitis (AS) is under investigated. We aimed to examine the association of IRF5 promoter methylation patterns and transcript levels with the susceptibility to AS.

METHODS

A total of 60 AS patients and 60 healthy controls were included in this study. We used the bisulfite conversion to detect the DNA methylation pattern of IRF5 promoter in whole blood, and the quantitative real-time PCR (qRT-PCR) to detect the relative mRNA expression level in peripheral blood mononuclear cells (PBMCs).

RESULTS

The overall methylation level of IRF5 promoter was lower in AS patients compared to healthy controls (P < 0.001). The methylation level of IRF5 promoter was negatively correlated with mRNA level (P = 0.005). The results of receiver operating characteristic curve (ROC) showed that the area under the curve (AUC) was 0.810 (P < 0.001), and the sensitivity and specificity were 71.67% and 85.00%, respectively. There were significant differences between the severe dysfunction group and healthy control group, and between the mild dysfunction group and healthy control group (P = 0.006 and P < 0.001, respectively). Only CRP was significantly correlated with mRNA relative level, while the others were not significant.

CONCLUSION

These findings indicate that IRF5 methylation profile may be involved in the pathological process of AS, and that it may help identify AS patients.

DNA Methylation and mRNA Expression of B7-H3 Gene in Ankylosing Spondylitis: A Case-Control Study

BACKGROUND

Ankylosing spondylitis (AS) is a common inflammatory arthritis, with a high prevalence in patients in their mid-20s. Its pathogenesis is not well understood; however, genetic factors likely play a critical role. Epigenetic DNA changes may be involved in the pathogenesis of AS. In this study, we explored the methylation and transcription levels of the B7-H3 gene and its association with AS in an eastern Chinese Han population.

METHODS

Peripheral blood of AS patients and healthy controls was used to extract genomic DNA and B7-H3 methylation levels were analyzed using sodium bisulfite followed by multiplex polymerase chain reaction. SPSS software was used to determine the statistical significance of the results.

RESULTS

Hypomethylation of the promoter of the B7-H3 gene was observed in AS patients, whereas the B7-H3 gene expression was significantly enhanced in AS patients.

CONCLUSION

Epigenetic modifications of B7-H3 were associated with susceptibility to AS. Hypomethylation of the B7-H3 promoter, which leads to B7-H3 overexpression, may be involved in the pathogenesis of AS.

DNA methylation and transcription of the FOXO3a gene are associated with ankylosing spondylitis

To explore the association between methylation level and transcript level of Forkhead box O3a (FOXO3a) gene with ankylosing spondylitis (AS) susceptibility. Methylation levels of the FOXO3a promoter were measured in 84 AS patients and 83 healthy controls. A total of 77 patients and 66 healthy subjects were included in subsequent mRNA level testing. DNA methylation levels of 107 CpG sites on 6 CpG islands in the FOXO3a gene were investigated. This study indicated that CpG-4 and CpG-5 islands were markedly hypomethylated in AS patients. The methylation level of CpG-4 island in AS patients was negatively correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and Ankylosing Spondylitis Disease Activity Score (ASDAS). Moreover, FOXO3a mRNA levels were significantly decreased in AS patients and were obviously negatively correlated with the methylation levels of CpG-2 and CpG-5 islands in AS patients without treatment. The sensitivity and specificity of differential methylated CpG sites of FOXO3a were 74.7 and 85.4%, respectively. Besides, FOXO3a mRNA had a sensitivity of 80.0% and a specificity of 68.8%. DNA methylation and transcription of FOXO3a might be related to AS susceptibility and play a crucial role in the diagnosis of AS, but many open questions remain.

Immune Regulation in Polycystic Ovary Syndrome

A polycystic ovarian syndrome (PCOS) is the most common endocrine disorder affecting females . Furthermore, it is a heterogeneous disease with a variety of etiologies and outcomes. Patients frequently complain about infertility, irregular menstruation, acne, seborrheic dermatitis, hirsutism, and obesity. PCOS can be caused by hypothalamic-pituitary-ovarian axis dysfunction, heredity, or metabolic abnormalities. PCOS is characterized by chronic low-level inflammation, which includes an imbalance in pro-inflammatory factor secretion, endothelial cell dysfunction, and leukocytosis. PCOS is also distinguished by hormonal and immune dysregulation. During PCOS, immune cells and immune regulatory molecules play critical roles in maintaining metabolic homeostasis and regulating immune responses. Because of oligo/anovulation, patients with PCOS have low progesterone levels. Therefore, low progesterone levels in PCOS overstimulate the immune system, causing it to produce more estrogen, which leads to a variety of autoantibodies. This review aims to summarize the immune regulation involved in the pathogenesis of PCOS and pave the way for the development of better PCOS treatment options in the near future.