Relationship between the Plasma Proteome and Changes in Inflammatory Markers after Bariatric Surgery.

Severe obesity is a disease associated with multiple adverse effects on health. Metabolic bariatric surgery (MBS) can have significant effects on multiple body systems and was shown to improve inflammatory markers in previous short-term follow-up studies. We evaluated associations between changes in inflammatory markers (CRP, IL6 and TNFα) and circulating proteins after MBS. METHODS: Sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics was performed on plasma samples taken at baseline (pre-surgery) and 6 and 12 months after MBS, and concurrent analyses of inflammatory/metabolic parameters were carried out. The change in absolute abundances of those proteins, showing significant change at both 6 and 12 months, was tested for correlation with the absolute and percentage (%) change in inflammatory markers. RESULTS: We found the following results: at 6 months, there was a correlation between %change in IL-6 and fold change in HSPA4 (rho = -0.659; p = 0.038) and in SERPINF1 (rho = 0.714, p = 0.020); at 12 months, there was a positive correlation between %change in IL-6 and fold change in the following proteins-LGALS3BP (rho = 0.700, p = 0.036), HSP90B1 (rho = 0.667; p = 0.05) and ACE (rho = 0.667, p = 0.05). We found significant inverse correlations at 12 months between %change in TNFα and the following proteins: EPHX2 and ACE (for both rho = -0.783, p = 0.013). We also found significant inverse correlations between %change in CRP at 12 months and SHBG (rho = -0.759, p = 0.029), L1CAM (rho = -0.904, p = 0.002) and AMBP (rho = -0.684, p = 0.042). CONCLUSION: Using SWATH-MS, we identified several proteins that are involved in the inflammatory response whose levels change in patients who achieve remission of T2DM after bariatric surgery in tandem with changes in IL6, TNFα and/or CRP. Future studies are needed to clarify the underlying mechanisms in how MBS decreases low-grade inflammation.

Changes in the Proteome Profile of People Achieving Remission of Type 2 Diabetes after Bariatric Surgery.

Bariatric surgery (BS) results in metabolic pathway recalibration. We have identified potential biomarkers in plasma of people achieving type 2 diabetes mellitus (T2DM) remission after BS. Longitudinal analysis was performed on plasma from 10 individuals following Roux-en-Y gastric bypass (n = 7) or sleeve gastrectomy (n = 3). Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) was done on samples taken at 4 months before (baseline) and 6 and 12 months after BS. Four hundred sixty-seven proteins were quantified by SWATH-MS. Principal component analysis resolved samples from distinct time points after selection of key discriminatory proteins: 25 proteins were differentially expressed between baseline and 6 months post-surgery; 39 proteins between baseline and 12 months. Eight proteins (SHBG, TF, PRG4, APOA4, LRG1, HSPA4, EPHX2 and PGLYRP) were significantly different to baseline at both 6 and 12 months post-surgery. The panel of proteins identified as consistently different included peptides related to insulin sensitivity (SHBG increase), systemic inflammation (TF and HSPA4-both decreased) and lipid metabolism (APOA4 decreased). We found significant changes in the proteome for eight proteins at 6- and 12-months post-BS, and several of these are key components in metabolic and inflammatory pathways. These may represent potential biomarkers of remission of T2DM.

Lifestyle intervention in individuals with impaired glucose regulation affects Caveolin-1 expression and DNA methylation.

AIMS: We investigated whether a lifestyle intervention could influence expression and DNA methylation of diabetes-related genes in patients with impaired glucose regulation (IGR), the results were compared to bariatric surgery, considering it an intensive change. METHODS: Twenty participants with IGR had adipose tissue biopsy and blood collected pre- and post-lifestyle (6 months) intervention; 12 obese patients had subcutaneous fat taken before and after bariatric surgery. RNA/DNA was extracted from all samples and underwent qPCR. DNA was bisulphite converted and 12 CpG sites of Caveolin-1 (CAV1) promoter were pyrosequenced. RESULTS: lifestyle intervention resulted in opposite direction changes in fat tissue and blood for CAV1 expression and DNA methylation and these changes were correlated between tissues, while no significative differences were found in CAV1 expression after bariatric surgery. CONCLUSIONS: Our findings suggest a role for CAV1 in modulating adipocyte function as a consequence of lifestyle changes, as exercises and diet. These results may provide insights into new therapeutic targets for diabetes prevention.

Assessment of global long interspersed nucleotide element-1 (LINE-1) DNA methylation in a longitudinal cohort of type 2 diabetes mellitus (T2DM) individuals.

INTRODUCTION: Recent studies have indicated that methylation of the LINE-1 elements is associated with an increased risk of worsening carbohydrate metabolism. It has been shown that overall DNA methylation of LINE-1 elements could be considered as a risk factor for T2DM and its complications, independent of other established risk factors. METHODS: A total of 794 T2DM individuals from Salford, UK were included in this study (60% men n = 470). All patients had clinical and metabolic variables measured in 2002 (baseline outcomes) and annually through to 2016. Global LINE-1 DNA methylation was measured at four CpG sites. The QIAGEN PyroMark Q96 MD pyrosequencer was used to quantify methylation. RESULTS: The overall mean ± SD global LINE-1 methylation was 75.81 ± 3.25%. Cross-sectional linear regression analysis at baseline year 2002 showed that LINE-1 methylation was a significant predictor of diastolic BP (adjusted beta coefficient ß = -0.25), estimated glomerular filtration rate (eGFR) (ß = -0.48) and cholesterol HDL ratio (ß = -0.04). A 10% increase in LINE-1 methylation was associated with a lower diastolic BP by 2.5 mm Hg, a lower eGFR by 4.8 ml/min/1.73 m2 and decreased cholesterol/HDL ratio by 0.4 mmol/L. Longitudinal analysis over the 14-year-follow-up periods showed that global LINE-1 methylation at baseline was associated with lower BMI in women [ß = -0.25] and lower cholesterol: HDL ratio [ß = -0.07]. A 10% increase in LINE-1 methylation was associated with reduction in BMI by 2.5 kg/m2 in women and reduction in cholesterol:HDL ratio by 0.7 mmol/L. CONCLUSION: In a 14-year longitudinal cohort of T2DM individuals, relations between global LINE-1 DNA methylation status and specific metabolic markers were seen. Also, a higher degree of DNA methylation was predictive of less weight gain over time in women.

Social Disadvantage Is Associated With Lower Vitamin D Levels in Older People and There Is No Surrogate for Its Measurement.

Introduction: There is increasing evidence concerning adverse health consequences of low vitamin D levels. We determined whether there is any surrogate for measuring vitamin D in people older than 70 years and the relation between index of multiple deprivation (IMD) and vitamin D levels. Methods: Blood samples from 241 patients were included in this analysis. Concurrent measurements for 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), and bone profile are reported. Results: The prevalence of total vitamin D insufficiency/deficiency (defined as total vitamin D <50 nmol/L) was 57.5% overall. Even for patients with vitamin D deficiency, a significant proportion had PTH, normal calcium, phosphate, and alkaline phosphatase levels. For patients with vitamin D <25 nmol/L, 62.7% had a PTH within reference range, 83.1% had normal serum-adjusted calcium, 80.6% had normal phosphate, and 85.1% had a normal serum alkaline phosphatase. With increasing quintiles of IMD, there was a 22% increased risk of vitamin D deficiency/insufficiency from quintiles 1 to 5, in age- and sex-adjusted logistic regression models (odds ratio [OR] = 1.22, 95% confidence interval [1.01, 1.47]; p = .034). Conclusion: No other parameter is currently adequate for screening for vitamin D deficiency in older people. A higher IMD is associated with lower vitamin D levels in older people.

Network analysis identifies protein clusters of functional importance in juvenile idiopathic arthritis.

INTRODUCTION: Our objective was to utilise network analysis to identify protein clusters of greatest potential functional relevance in the pathogenesis of oligoarticular and rheumatoid factor negative (RF-ve) polyarticular juvenile idiopathic arthritis (JIA). METHODS: JIA genetic association data were used to build an interactome network model in BioGRID 3.2.99. The top 10% of this protein:protein JIA Interactome was used to generate a minimal essential network (MEN). Reactome FI Cytoscape 2.83 Plugin and the Disease Association Protein-Protein Link Evaluator (Dapple) algorithm were used to assess the functionality of the biological pathways within the MEN and to statistically rank the proteins. JIA gene expression data were integrated with the MEN and clusters of functionally important proteins derived using MCODE. RESULTS: A JIA interactome of 2,479 proteins was built from 348 JIA associated genes. The MEN, representing the most functionally related components of the network, comprised of seven clusters, with distinct functional characteristics. Four gene expression datasets from peripheral blood mononuclear cells (PBMC), neutrophils and synovial fluid monocytes, were mapped onto the MEN and a list of genes enriched for functional significance identified. This analysis revealed the genes of greatest potential functional importance to be PTPN2 and STAT1 for oligoarticular JIA and KSR1 for RF-ve polyarticular JIA. Clusters of 23 and 14 related proteins were derived for oligoarticular and RF-ve polyarticular JIA respectively. CONCLUSIONS: This first report of the application of network biology to JIA, integrating genetic association findings and gene expression data, has prioritised protein clusters for functional validation and identified new pathways for targeted pharmacological intervention.

Identification of multiple, oxygen-stable HIF1 alpha isoforms, and augmented expression of adrenomedullin in rheumatoid arthritis.

OBJECTIVES: To identify and quantitate hypoxia inducible factor 1 alpha (HIF1 α) isoforms in circulating peripheral blood mononuclear cells (PBMCs), and to assess their effects on target gene expression in rheumatoid arthritis (RA) patients. METHODS: PBMCs from healthy controls and from RA patients were analysed ex-vivo for expression of HIF isoforms, and target genes were assessed by RT-PCR. RESULTS: Transcripts of multiple HIF1α isoforms exist in circulating PBMCs. Expression of all these isoforms is dramatically, and maximally, augmented by foreign surface recognition. However, HIF1α protein stabilisation requires additional cell activation with phorbol ester. No difference in the expression or regulation of the HIF1α isoforms was seen between patients with active RA and healthy controls. However, analysis of a panel of HIF1α target genes revealed increased basal expression of the adrenomedullin gene in RA PBMCs, with resulting loss of further induction upon cell activation. CONCLUSIONS: Even in normoxia PBMCs express stable HIF1α protein on cell activation. Whilst multiple HIF1α isoforms exist in PBMCs no differences in expression were seen in RA compared with healthy controls. RA causes constitutive adrenomedullin expression in PBMCs that is not explicable by altered HIF expression, or stabilisation. Adrenomedullin has a variety of potential biological roles in RA, including regulation of angiogenesis, and aberrant gene regulation may be relevant in RA pathogenesis.

Autoinflammatory gene polymorphisms and susceptibility to UK juvenile idiopathic arthritis.

BACKGROUND: To investigate the autoinflammatory hereditary periodic fever syndrome genes MVK and TNFRSF1A, and the NLRP1 and IL1 genes, for association with juvenile idiopathic arthritis (JIA). METHODS: For MVK, TNFRSF1A and NLRP1 pair-wise tagging SNPs across each gene were selected and for IL1A SNPs from a prior meta-analysis were included. 1054 UK Caucasian JIA patients were genotyped by Sequenom iPlex MassARRAY and allele and genotype frequencies compared with 5380 unrelated healthy UK Caucasian controls. RESULTS: Four SNPs were significantly associated with UK JIA: rs2071374 within intron 4 of IL1A (ptrend=0.006), rs2228576 3' of TNFRSF1A (ptrend=0.009) and 2 SNPs, rs11836136 and rs7957619, within MVK (ptrend=0.006, ptrend=0.005 respectively). In all cases the association appeared to be driven by the systemic-onset JIA (SoJIA) subtype. Genotype data for the two MVK SNPs was available in a validation cohort of 814 JIA (oligoarticular and RF negative polyarticular) cases and 3058 controls from the US. Replication was not confirmed, however, further suggesting that this association is specific to SoJIA. CONCLUSIONS: These findings extend the observations of the relevance of studying monogenic loci as candidates for complex diseases. We provide novel evidence of association of MVK and TNFRSF1A with UK JIA, specifically driven by association with SoJIA and further confirm that the IL1A SNP association with SoJIA is subtype specific. Replication is required in independent cohorts.

No evidence for genetic association of interferon regulatory factor 1 in juvenile idiopathic arthritis.

OBJECTIVE: Juvenile idiopathic arthritis (JIA) comprises several clinically distinct subgroups and is the most widespread cause of chronic childhood disability. A significant association between JIA and a polymorphism in the interferon regulatory factor 1 (IRF-1) gene has previously been reported, implicating IRF1 in disease susceptibility. The aim of this study was to replicate the IRF1 association in JIA using single-marker and haplotype analyses in a case-control study, using control subjects different from those in the previous study and a larger cohort of patients (n = 765). METHODS: DNA from 765 patients with JIA and 508 unaffected control subjects was genotyped for 4 single-nucleotide polymorphisms in the IRF-1 gene. Association of genotypes at the IRF1 loci was assessed using single-marker and haplotype analyses. RESULTS: No significant differences in genotype frequency or allele frequency were observed between patients and control subjects. CONCLUSION: This replication study used a much larger patient cohort to examine the association of IRF1 in JIA. However, despite the increased statistical power, we observed no significant association for IRF1 markers, either individually or as haplotypes. It is therefore unlikely that this gene is involved in JIA susceptibility.

Macrophage migration inhibitory factor gene polymorphism is associated with psoriasis.

Macrophage migration inhibitory factor (MIF), an important pro-inflammatory cytokine, is over-expressed in plaques of psoriasis and increased levels are found in the sera of patients with psoriasis. Promoter polymorphisms of the MIF gene are associated with increased production of MIF and have been found to confer increased risk of susceptibility to chronic inflammatory diseases. We investigated whether there is an association between promoter polymorphisms of the MIF gene and chronic plaque psoriasis. Two hundred and twenty-eight UK caucasian patients with chronic plaque psoriasis, and a control panel of 401 UK caucasian normal volunteers were studied. MIF promoter polymorphisms were genotyped by allelic discrimination, or by a fluorescently labeled primer method, and capillary gel electrophoresis. Carriage of either the MIF-173*C polymorphism or the MIF CATT(7) polymorphism was positively correlated with psoriasis (odds ratios (OR) 1.52 95% confidence intervals (CI) 1.05-2.19 (p=0.024) and OR 1.67 95% CI 1.1-2.5 (p=0.013), respectively. The OR for presence of the CATT(7)-MIF-173(*)C haplotype versus all other haplotypes combined was 1.69 95% CI 1.2-2.5 (p=0.008). The results provide evidence for polymorphisms in the MIF gene, and in particular the CATT(7)-MIF-173(*)C haplotype, being of importance in susceptibility to psoriasis.

Evidence for linkage of HLA loci in juvenile idiopathic oligoarthritis: independent effects of HLA-A and HLA-DRB1.

OBJECTIVE: Although multiple associations between HLA loci and juvenile oligoarthritis have previously been documented, evidence for linkage of HLA loci in oligoarthritis in UK Caucasians with juvenile idiopathic arthritis (JIA) has not been described. The aim of this study was to investigate linkage of HLA-A, B, and DRB1 in UK Caucasian JIA patients with oligoarthritis. METHODS: One hundred forty-two families comprising affected offspring and their parents (45 with one parent available and 97 with both parents available) were typed for HLA-A, B, and DRB1 by polymerase chain reaction-sequence-specific oligonucleotide probe. Single-point and multipoint analyses were performed using various modifications of the extended transmission disequilibrium test. Linkage disequilibrium (LD) analysis was performed using the EH-Plus system. RESULTS: Linkage to HLA-A and HLA-DRB1 was seen in oligoarthritis and in the International League of Associations for Rheumatology-defined subgroups of persistent oligoarthritis and extended oligoarthritis. Linkage to HLA-A, B, and DRB1 was also observed in female patients with oligoarthritis. Linkage of the HLA loci seemed to be attributable to maternal preferential transmission of alleles. Furthermore, LD patterns between the HLA-A, B, and DRB1 loci were investigated. HLA-A and HLA-DRB1 were confirmed as independent susceptibility loci for oligoarthritis. CONCLUSION: This is the first study to establish linkage of HLA-A and HLA-DRB1 in oligoarthritis and to show that the 2 loci contribute independently to disease. Further studies are being performed to determine whether it is these loci or other genes in LD with them that are responsible for susceptibility to oligoarthritis in UK Caucasian patients with JIA.

Macrophage migration inhibitory factor gene polymorphism is associated with sarcoidosis in biopsy proven erythema nodosum.

OBJECTIVE: To assess whether polymorphism of the macrophage migration inhibitory factor (MIF) gene at the position -173 is implicated in the development of sarcoidosis. METHODS: Twenty-eight patients with biopsy proven erythema nodosum (EN) associated with sarcoidosis, 70 patients with biopsy proven EN related to other etiologies, and 122 healthy matched controls from the Lugo region of Northwest Spain were studied. Patients and controls were genotyped for a single nucleotide polymorphism in the 5'-flanking region at position -173 of the MIF gene, using SNapshot ddNTP primer extension, followed by capillary electrophoresis (ABI 3100). RESULTS: A significantly increased frequency of the C mutant allele was observed in patients with EN secondary to sarcoidosis compared to controls (p = 0.0016; p(corr) = 0.0032; OR 2.78, 95% CI 1.45, 5.35) and also compared to patients with EN unrelated to sarcoidosis (p = 0.0004; p(corr) = 0.0008; OR 3.72, 95% CI 1.75, 7.87). Patients with EN carrying an MIF 173 C allele were found to have an increased risk of sarcoidosis (57% in EN secondary to sarcoidosis vs 24% in patients with EN related to other etiologies; p = 0.002; p(corr) = 0.004; OR 4.16, 95% CI 1.64, 10.50). CONCLUSION: This is the first attempt to assess the influence of MIF genetic polymorphism at position -173 in the development of sarcoidosis. The MIF 173 C allele is associated with a significantly increased risk of developing sarcoidosis in patients with EN.