DNA methylation of ITGB2 contributes to allopurinol hypersensitivity.

BACKGROUNDS: HLA-B*58:01 allele was strongly associated with allopurinol induced severe cutaneous adverse drug reaction (SCAR). However, HLA-B genotype is not sufficient to predict the occurrence of allopurinol-induced SCAR. OBJECTIVE: To discover DNA methylation markers for allopurinol-induced SCAR which may improve the prediction accuracy of genetic testing. STUDY DESIGN: The study was designed as a retrospective case-control clinical study in multicenter hospitals across Taiwan, Mainland China, Malaysia and Canada. 125 cases of allopurinol-induced SCAR patients and 139 cases of allopurinol tolerant controls were enrolled in this study during 2005 to 2021. RESULTS: The results of genome-wide DNA methylation assay of 62 patients revealed that ITGB2 showed strong discriminative ability of allopurinol-induced SCAR in both HLA-B*58:01 positive and negative patients with AUC value of 0.9364 (95% CI 0.8682-1.000). In validation study, significant hypermethylation of ITGB2 were further validated in allopurinol-induced SCAR patients compared to tolerant controls, especially in those without HLA-B*58:01(AUC value of 0.8814 (95% CI 0.7121-1.000)). Additionally, the methylation levels of 2 sites on ITGB2 were associated with SCAR phenotypes. Combination of HLA-B*58:01 genotyping and ITGB2 methylation status could improve the prediction accuracy of allopurinol-induced SCAR with the AUC value up to 0.9387 (95% CI 0.9089-0.9684), while the AUC value of HLA-B*58:01 genotyping alone was 0.8557 (95% CI 0.8030-0.9083). CONCLUSIONS: Our study uncovers differentially methylated genes between allopurinol-induced SCAR patients and tolerant controls with positive or negative HLA-B*58:01 allele and provides the novel epigenetic marker that improves the prediction accuracy of genetic testing for prevention of allopurinol-induced SCAR.

Downregulation of BDH2 modulates iron homeostasis and promotes DNA demethylation in CD4+ T cells of systemic lupus erythematosus.

DNA hypomethylation plays an important role in the pathogenesis of systemic lupus erythematosus (SLE). Here we investigated whether 3-hydroxy butyrate dehydrogenase 2 (BDH2), a modulator of intracellular iron homeostasis, was involved in regulating DNA hypomethylation and hyper-hydroxymethylation in lupus CD4+ T cells. Our results showed that BDH2 expression was decreased, intracellular iron was increased, global DNA hydroxymethylation level was elevated, while methylation level was reduced in lupus CD4+ T cells compared with healthy controls. The decreased BDH2 contributed to DNA hyper-hydroxymethylation and hypomethylation via increasing intracellular iron in CD4+ T cells, which led to overexpression of immune related genes. Moreover, we showed that BDH2 was the target gene of miR-21. miR-21 promoted DNA demethylation in CD4+ T cells through inhibiting BDH2 expression. Our data demonstrated that the dysregulation of iron homeostasis in CD4+ T cells induced by BDH2 deficiency contributes to DNA demethylation and self-reactive T cells in SLE.

Two new susceptibility loci 1q24.2 and 11p11.2 confer risk to severe acne.

Severe acne is a chronic inflammatory skin disorder characterized by widespread inflammatory lesions including nodules, cysts and potential scarring. Here we perform the first genome-wide association study of severe acne in a Chinese Han population comprising 1,056 cases and 1,056 controls using the Illumina HumanOmniZhongHua-8 BeadChip. In an independent cohort of 1,860 cases and 3,660 controls of Chinese Han, we replicate 101 SNPs of which 3 showed consistent association. We identify two new susceptibility loci at 11p11.2 (DDB2, rs747650, P(combined)=4.41 × 10⁻9 and rs1060573, P(combined)=1.28 × 10⁻8) and 1q24.2 (SELL, rs7531806, P(combined)=1.20 × 10⁻8) that are involved in androgen metabolism, inflammation processes and scar formation in severe acne. These results point to new genetic susceptibility factors and suggest several new biological pathways related to severe acne.

[Histone H3 acetylation of tumor necrosis factor-alpha and cyclooxygenase-2 in patients with type 2 diabetes].

OBJECTIVE: To investigate the expression of tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) mRNA and evaluate the status of histone H3 acetylation at TNF-α and COX-2 promoter in peripheral blood mononuclear cells (PBMCs) from type 2 diabetics. METHODS: The PBMCs from 12 type 2 diabetics and 12 healthy controls were isolated by Ficoll-Hypaque density gradient centrifugation. The differential expression of TNF-α and COX-2 mRNA was measured by real-time PCR (polymerase chain reaction). Chromatin immunoprecipitation analysis was used to detect the status of H3 acetylation at TNF-α and COX-2 promoter region. RESULTS: TNF-α and COX-2 mRNA were overexpressed in PBMCs from Type 2 diabetics as compared with normal controls (2.28 ± 0.09 fold and 2.78 ± 0.26 fold).(P < 0.05). Compared with normal controls, H3 acetylation at the TNF-α (1.54 ± 0.43 vs 0.97 ± 0.39, P = 0.0094) and COX-2 (1.20 ± 0.58 vs 0.64 ± 0.21, P = 0.0161) gene promoter region was elevated in PBMCs from Type 2 diabetic patients. CONCLUSION: Increased H3 acetylation at TNF-α and COX-2 promoter in PBMCs from type 2 diabetics may contribute to the pathogenesis of type 2 diabetes through the elevated expressions of TNF-α and COX-2.