Association between Air Pollution and Type 2 Diabetes Mellitus in Developing Countries: A Systematic Review and Meta-Analysis.

Objective In recent years, many studies have reported that air pollution is a risk factor for type 2 diabetes mellitus (T2DM). The aim of this systematic review and meta-analysis is to summarize the evidence about the association between exposure to air pollution and T2DM in developing countries. Methods The databases, including PubMed, EMBASE and Web of Science, were systematically searched for studies published up to 31 March 2022. Studies about the association between air pollution and T2DM prevalence or incidence in developing countries were included. The odds ratio (OR) was used as effect estimate. We synthesized the included studies in the meta-analysis. Results We included 8 cross-sectional studies and 8 cohort studies, all conducted in developing countries. Meta-analysis of 8 studies on PM2.5 (particulate matter ≤ 2.5 µm in diameter) showed that T2DM prevalence was significantly associated with PM2.5 exposure (OR=1.12; 95% CI: 1.07, 1.17; P<0.001). The association between air pollutants and T2DM incidence was not estimated due to the limited relevant studies. Conclusions The exposure to PM2.5 would be positively associated with an increased prevalence of T2DM in developing countries. Some effective measures should be taken to reduce air pollutant exposure in people who are vulnerable to diabetes.

Genome-wide DNA methylation patterns in monocytes derived from patients with primary Sjogren syndrome.

BACKGROUND: Epigenetics, especially DNA methylation, plays an important role in the pathogenesis of primary Sjogren syndrome (pSS). Our study aimed to reveal the role of DNA methylation in peripheral monocytes of pSS patients. METHODS: A total of 11 pSS patients and five age-matched healthy controls (HCs) were included in this study. Monocytes were isolated from peripheral blood mononuclear cells using magnetic microbeads. DNA methylation profiles were generated using Human Methylation 850K BeadChips. RESULTS: In monocytes from pSS patients, we identified 2819 differentially methylated positions (DMPs), comprising 1977 hypomethylated- and 842 hypermethylated-DMPs, corresponding to 1313 unique genes when compared with HCs. IFI44L, MX1, PAARP9, and IFITM1, which influence the interferon (IFN) signaling pathway, were among the genes hypomethylated in pSS. Functional analysis of genes with a minimum of two DMPs showed involvement in antigen binding, transcriptional regulation, cell adhesion, IFN-γ pathway, type I IFN pathway, antigen presentation, Epstein-Barr virus infection, human T-lymphotropic virus type 1 virus infection, and metabolic disease-related pathways. In addition, patients with higher serum IgG levels exhibited enrichment in Notch signaling and metabolic-related pathways. Upon comparing monocytes with salivary gland epithelial cells, an important overlap was observed in the cell cycle, cell senescence, and interleukin-17 signaling pathways. The differentially methylated genes were more enriched in the ribosome- and AMP-activated protein kinase signaling pathway in anti-Ro/SSA and anti-La/SSB autoantibodies double-positive patients. CONCLUSION: Genome-wide DNA methylation profiling revealed significant differences in DNA methylation in monocytes isolated from patients with pSS.

Exploring pathogenesis of primary biliary cholangitis by proteomics: A pilot study.

AIM: To explore the pathogenesis of primary biliary cholangitis (PBC) by identifying candidate autoantibodies in serum samples by proteomics and bioinformatics. METHODS: Nine antimitochondrial antibody (AMA)-positive PBC patients and nine age- and sex-matched AMA-negative PBC patients were recruited. Antigen enrichment technology was applied to capture autoantigens of human intrahepatic biliary epithelial cells (HiBECs) that are recognized by autoantibodies from the sera of PBC patients. Candidate autoantigens were identified by label-free mass spectrometry. Bioinformatics analysis with MaxQuant software (version 1.5.2.8), DAVID platform, and Cytoscape v.3.0 allowed illustration of pathways potentially involved in the pathogenesis of PBC. RESULTS: In total, 1081 candidate autoantigen proteins were identified from the PBC patient pool. Among them, 371 were determined to be significantly differentially expressed between AMA-positive and -negative PBC patients (P < 0.05). Fisher's exact test was performed for enrichment analysis of Gene Ontology protein annotations (biological processes, cellular components, and molecular functions) and the Kyoto Encyclopedia of Genes and Genomes pathways. Significantly different protein categories were revealed between AMA-positive and -negative PBC patients. As expected, autoantigens related to mitochondria were highly enriched in AMA-positive PBC patients. However, lower levels of AMA were also detected in AMA-negative PBC patients. In addition, autoantigens of AMA-negative PBC patients were mainly involved in B-cell activation, recognition of phagocytosis, and complement activation. CONCLUSION: AMA-negative PBC individuals may not exist, but rather, those patients exhibit pathogenesis pathways different from those of AMA-positive PBC. Comprehensive research is needed to confirm these observations.

A single-nucleotide polymorphism of CCL21 rs951005 T>C is associated with susceptibility of polymyositis and such patients with interstitial lung disease in a Chinese Han population.

OBJECTIVES: Our objective was to better understand the roles of single nucleotide polymorphisms (SNPs) in the CCL21, ERBB3, and TERT genes region in the development of idiopathic inflammatory myopathies (IIMs), we explored the associations between SNPs in the mentioned three genes and IIMs susceptibility in a Chinese Han population. METHODS: Chinese polymyositis (PM) patients (n =291), dermatomyositis (DM) patients (n=526) and ethnically-matched healthy controls (n =968) were genotyped for the CCL21 region SNPs (rs951005 and rs2492358), ERBB3 (rs2292239 and rs11171739), and TERT (rs2853676 and rs10069690), by using the Sequenom MassArray system. RESULTS: Our study indicated strong allele and genotype associations between rs951005 (OR: 1.65, 95%CI: 1.18-2.30, Pc=0.015; Pc=0.041, respectively) in CCL21 gene and PM patients. Additionally, rs951005 was associated with interstitial lung disease (ILD) in PM patients (Pc =0.01), and was associated with PM patients in additive model. However, the Chinese Han PM/DM patients and controls had statistically similar frequencies of alleles, genotypes and different genetic models (additive, dominant, and recessive) of ERBB3 and TERT polymorphisms. CONCLUSIONS: This was the first study to demonstrate that the CCL21 gene SNP (rs951005) might confer genetic predisposition to PM patients or such patients with ILD in a Chinese Han population.

Identification of new autoantigens for primary biliary cirrhosis using human proteome microarrays.

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease of unknown etiology and is considered to be an autoimmune disease. Autoantibodies are important tools for accurate diagnosis of PBC. Here, we employed serum profiling analysis using a human proteome microarray composed of about 17,000 full-length unique proteins and identified 23 proteins that correlated with PBC. To validate these results, we fabricated a PBC-focused microarray with 21 of these newly identified candidates and nine additional known PBC antigens. By screening the PBC microarrays with additional cohorts of 191 PBC patients and 321 controls (43 autoimmune hepatitis, 55 hepatitis B virus, 31 hepatitis C virus, 48 rheumatoid arthritis, 45 systematic lupus erythematosus, 49 systemic sclerosis, and 50 healthy), six proteins were confirmed as novel PBC autoantigens with high sensitivities and specificities, including hexokinase-1 (isoforms I and II), Kelch-like protein 7, Kelch-like protein 12, zinc finger and BTB domain-containing protein 2, and eukaryotic translation initiation factor 2C, subunit 1. To facilitate clinical diagnosis, we developed ELISA for Kelch-like protein 12 and zinc finger and BTB domain-containing protein 2 and tested large cohorts (297 PBC and 637 control sera) to confirm the sensitivities and specificities observed in the microarray-based assays. In conclusion, our research showed that a strategy using high content protein microarray combined with a smaller but more focused protein microarray can effectively identify and validate novel PBC-specific autoantigens and has the capacity to be translated to clinical diagnosis by means of an ELISA-based method.