Association of leucocyte relative telomere length with incident type 2 diabetes mellitus in the Bruneck Study (n = 606, 44 events).

<p>Asterisks indicate level of statistical significance: *P≤0.05; **P≤0.01; ***P≤0.001. Abbreviations: BMI, body mass index; HDL-C, high density lipoprotein cholesterol; hsCRP; high-sensitivity C-reactive protein; RTL, relative telomere length; SES, socio-economic status; T2DM, type 2 diabetes mellitus; WHR, waist-hip ratio. Participants with a baseline history of type 2 diabetes mellitus were excluded from the analysis (n = 78).</p><p>Association of leucocyte relative telomere length with incident type 2 diabetes mellitus in the Bruneck Study (n = 606, 44 events).</p

Study flow diagram of the literature-based meta-analysis.

<p>The figure is based on the 2009 PRISMA flow diagram template (available from <a href="http://www.prisma-statement.org/statement.htm" target="_blank">http://www.prisma-statement.org/statement.htm</a>).</p

Association of leucocyte relative telomere length an risk of type 2 diabetes mellitus in the Bruneck Study (n = 606, 44 events over follow-up 1995–2010).

<p>Cox models were adjusted for age, sex, body mass index, smoking, socio-economic status, physical activity, alcohol consumption, high density lipoprotein cholesterol, log high-sensitivity C-reactive protein, and waist-hip ratio. Abbreviations: CI, confidence interval; HR, hazard ratio; RTL, relative telomere length; T2DM, type 2 diabetes mellitus.</p

Description and meta-analysis of published data from three prospective cohort studies on the association of short telomeres and risk of type 2 diabetes mellitus.

<p>Published relative risks were pooled by random-effects meta-analysis. In the Bruneck Study and the Strong Heart Family Study, type 2 diabetes was defined according to the 1997 American Diabetes Association criteria. In the WHI Observational Study, diabetes was defined based on self-report and hospitalisation for type 2 diabetes. All three studies measured telomere length with a quantitative polymerase chain reaction technique. *Reported relative risks were additionally adjusted for two variables in the Bruneck Study (HDL cholesterol and log hsCRP), three variables in the Strong Heart Family Study (age², fasting glucose, total triglycerides), and three variables in the Women's Health Initiative Observational Study (date of blood collection, clinical centre, hormone therapy). †Max. ‡Mean. $The Women's Health Initiative Observational Study involved postmenopausal women who proved to be ineligible or unwilling to be randomised as part of the Women's Health Initiative Clinical Trial. Abbreviations: CI, confidence interval; NOS, Newcastle-Ottawa Scale for assessing the quality of nonrandomised studies in meta-analyses; T2DM, type 2 diabetes mellitus; WHI, Women's Health Initiative.</p

Baseline characteristics of the Bruneck Study population and their cross-sectional association with leucocyte relative telomere length (1995, n = 684).

<p>Standardised mean differences in leucocyte relative telomere length were adjusted for age and sex. Asterisks indicate level of statistical significance: *P≤0.05; **P≤0.01; ***P≤0.001. The mean (SD) of HbA1c was 5.8% (3.7%) in DCCT-derived units and 40 mmol/mol (17 mmol/mol) in SI units. Abbreviations: ApoB, apolipoprotein B; ApoB-IC, apoB-immune complexes; CI, confidence interval; Cu-OxLDL, copper-oxidised low-density lipoprotein; HbA1c, glycated haemoglobin; HDL, high-density lipoprotein; HOMA-IR, homeostatic model assessment of insulin resistance; hsCRP, high-sensitivity C-reactive protein; IgG, immunoglobulin G; IgM, immunoglobulin M; LDL, low-density lipoprotein; RTL, relative telomere length; MDA, malondialdehyde; OxPL/apoB, oxidised phospholipids on apolipoprotein B-100; SD, standard deviation; RLU, relative light unit; SMD, standardised mean difference; WHR, waist-hip ratio.</p

Distribution of baseline leucocyte relative telomere length in the Bruneck Study according to different disease states (1995, n = 684).

<p>Abbreviations: RTL, relative telomere length; T2DM, type 2 diabetes mellitus. There were 390 participants with normoglycaemia, 216 participants with impaired fasting glucose, and 78 participants with a clinical diagnosis of T2DM.</p

Functional <i>IL6R</i> 358Ala Allele Impairs Classical IL-6 Receptor Signaling and Influences Risk of Diverse Inflammatory Diseases

<div><p>Inflammation, which is directly regulated by interleukin-6 (IL-6) signaling, is implicated in the etiology of several chronic diseases. Although a common, non-synonymous variant in the IL-6 receptor gene (<i>IL6R</i> Asp358Ala; rs2228145 A>C) is associated with the risk of several common diseases, with the 358Ala allele conferring protection from coronary heart disease (CHD), rheumatoid arthritis (RA), atrial fibrillation (AF), abdominal aortic aneurysm (AAA), and increased susceptibility to asthma, the variant's effect on IL-6 signaling is not known. Here we provide evidence for the association of this non-synonymous variant with the risk of type 1 diabetes (T1D) in two independent populations and confirm that rs2228145 is the major determinant of the concentration of circulating soluble IL-6R (sIL-6R) levels (34.6% increase in sIL-6R per copy of the minor allele 358Ala; rs2228145 [C]). To further investigate the molecular mechanism of this variant, we analyzed expression of IL-6R in peripheral blood mononuclear cells (PBMCs) in 128 volunteers from the Cambridge BioResource. We demonstrate that, although 358Ala increases transcription of the soluble <i>IL6R</i> isoform (<i>P</i> = 8.3×10⁻²²) and not the membrane-bound isoform, 358Ala reduces surface expression of IL-6R on CD4+ T cells and monocytes (up to 28% reduction per allele; <i>P</i>≤5.6×10⁻²²). Importantly, reduced expression of membrane-bound IL-6R resulted in impaired IL-6 responsiveness, as measured by decreased phosphorylation of the transcription factors STAT3 and STAT1 following stimulation with IL-6 (<i>P</i>≤5.2×10⁻⁷). Our findings elucidate the regulation of IL-6 signaling by IL-6R, which is causally relevant to several complex diseases, identify mechanisms for new approaches to target the IL-6/IL-6R axis, and anticipate differences in treatment response to IL-6 therapies based on this common <i>IL6R</i> variant.</p> </div

The 358Ala allele is associated with decreased levels of membrane-bound IL-6R.

<p>Surface expression of IL-6R was quantified by flow cytometry in cryopreserved PBMCs from 128 volunteers from the Cambridge BioResource. Donors were sampled according to rs2228145 genotype. IL-6R surface expression was measured in four distinct immune cell subsets: CD4+ naïve and memory T cells, CD4+ regulatory T cells (Treg) and monocytes. Scatter plots depict the individual normalized IL-6R fluorescence intensity values measured as molecules of equivalent fluorochrome (MEF; see Methods for details). Error bars represent the standard error of the mean as shown by the middle horizontal line. The horizontal grey dotted reference line represents the average background fluorescence signal of the isotype control group. Differences in the mean expression levels, relative to the common homozygote group (Asp/Asp) are indicated above the horizontal black lines. <i>P</i>-values represent test for an association of rs2228145 with surface IL-6R levels, using an additive allelic effects model (see Methods for details).</p

The 358Ala allele is associated with reduced IL-6 signaling potential.

<p>(A) Frequency of pSTAT3 and (B) pSTAT1 positive cells following stimulation of PBMCs with 0, 0.1, 1 or 10 ng/ml of IL-6. Intracellular levels of pSTAT3 and pSTAT1 were measured by flow cytometry in three distinct immune cell subsets: CD4+ naïve T cells, CD4+ memory T cells and monocytes in 14 Asp/Asp and 14 Ala/Ala volunteers from the Cambridge BioResource. Median and interquartile range of the distribution of the frequency of pSTAT3 and pSTAT1 positive events in the two genotype groups for each dose of IL-6 stimulation are plotted. <i>P</i>-values represent tests for differences between rs2228145 genotype groups in pSTAT activation compared to control across doses. (see Methods and <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003444#pgen.1003444.s006" target="_blank">Figure S6</a> for details).</p

Comparison of the marginal phenotype-SNP associations provided by GUESS and SNPTEST in the multiple traits analysis of TG-LDL-APOB.

<p>(To increase readability, the log₁₀(BFs) are truncated at 20). (A) Genome-wide log₁₀(BF) obtained from GUESS. Significant SNPs found associated at 5% FDR are depicted by black dots (with the SNP's name) whereas significant SNPs that are also in the top Best Model Visited are represented by red dots (with the SNP's name). (B) Genome-wide log₁₀(BF) obtained from SNPTEST. The horizontal dashed line indicates the level of log₁₀(BF) that provides strong evidence of a phenotype-SNP association with Marginal Posterior Probability of inclusion close to 1. For comparison purposes, SNPs found by GUESS are highlighted (their name is printed). SNPs with log₁₀(BF)>5 are coloured coded according to the level of pairwise Pearson correlation with the closest significant GUESS SNP (see colour bar for correlation scale). (C) log₁₀(BF) signal obtained from SNPTEST in a region of chromosome 11 spanning nearly 500 Kb (116,519,739–116,845,104 bp). The horizontal dashed line and colour code used to identify relevant SNPs are as defined in (B). Top bars indicate the position of genes in the region retrieved from Ensembl R66. (D) Scatterplot of genome-wide log₁₀(BF) of TG-LDL-APOB obtained from GUESS and SNPTEST. The colour code used to identify relevant SNPs and the horizontal dashed line are as defined in (A) and (B).</p