BACKGROUND

C-reactive protein (CRP) is a heritable marker of chronic inflammation that is strongly associated with cardiovascular disease. We sought to identify genetic variants that are associated with CRP levels.

RESULTS

We performed a genome-wide association analysis of CRP in 66 185 participants from 15 population-based studies. We sought replication for the genome-wide significant and suggestive loci in a replication panel comprising 16 540 individuals from 10 independent studies. We found 18 genome-wide significant loci, and we provided evidence of replication for 8 of them. Our results confirm 7 previously known loci and introduce 11 novel loci that are implicated in pathways related to the metabolic syndrome (APOC1, HNF1A, LEPR, GCKR, HNF4A, and PTPN2) or the immune system (CRP, IL6R, NLRP3, IL1F10, and IRF1) or that reside in regions previously not known to play a role in chronic inflammation (PPP1R3B, SALL1, PABPC4, ASCL1, RORA, and BCL7B). We found a significant interaction of body mass index with LEPR (P<2.9×10(-6)). A weighted genetic risk score that was developed to summarize the effect of risk alleles was strongly associated with CRP levels and explained ≈5% of the trait variance; however, there was no evidence for these genetic variants explaining the association of CRP with coronary heart disease.

CONCLUSIONS

We identified 18 loci that were associated with CRP levels. Our study highlights immune response and metabolic regulatory pathways involved in the regulation of chronic inflammation.

Six novel genes encoding proteins with the interleukin (IL)-1 fold have been identified recently. The classical family members are involved in inflammatory signaling. Previous work has placed the novel genes close to or within the same cluster as IL1A, IL1B, and IL1RN, which occupy an approximately 400-kb interval on chromosome 2. We have combined the incomplete public database sequence with our own sequence to generate a reference sequence and map that encompass all of the novel genes, allowing determination of the gene structures, precise localization of exons, and determination of distances between conventional SNP and microsatellite markers. Gene order from centromere to telomere is IL1A-IL1B-IL1F7-IL1F9-IL1F6-IL1F8-IL1F5-IL1F10-IL1RN, of which only IL1A, IL1B, and IL1F8 are transcribed towards the centromere. The gene order relates to the evolutionary relationship between the genes. Key features of exon boundaries are conserved. There is no evidence for other IL-1 family members within the cluster.

OBJECTIVE

The interleukin-1 (IL-1) cytokine elicits a wide variety of biologic activities that initiate and promote an inflammatory response. The loci in the IL1 gene cluster have recently been associated with ankylosing spondylitis (AS). Since there is clinical and immunologic overlap between psoriatic arthritis (PsA) and AS, we wanted to examine the association between a panel of single-nucleotide polymorphisms (SNPs) in the IL1 gene family cluster and chromosome 2q12-13 in a PsA cohort.

METHODS

Two hundred twelve PsA patients and 150 ethnically matched controls were genotyped with 11 SNPs in IL1A, 9 SNPs in IL1B, and 9 SNPs in IL1F5-10. Univariate analyses of the 29 single markers and short intragenic haplotypes identified several associated regions. Seventeen markers of interest were noted and further investigated to determine which markers or short haplotypes independently predict case-control status, using a stepwise logistic model. RESULTS; Two regions contributing independently to risk of disease in PsA were noted: a region spanned by markers rs3783547, rs3783543, and rs17561 in IL1A, and a region near the end of IL1B, through IL1F7, IL1F8, and into IL1F10. The best model contained markers rs3811047, rs1562304, and rs3811058, and 1 haplotype constructed from the 3 markers in region 1, with a likelihood ratio of 25.34 (4 degrees of freedom).

CONCLUSIONS

The IL1 locus appears to be a high-priority susceptibility locus in PsA, with at least 2 independent regions that confer increased risk.

OBJECTIVE

The aim of the current study was to determine the contribution of interleukin (IL)1 gene cluster polymorphisms previously implicated in susceptibility for ankylosing spondylitis (AS) to AS susceptibility in different populations worldwide.

METHODS

Nine polymorphisms in the IL1 gene cluster members IL1A (rs2856836, rs17561 and rs1894399), IL1B (rs16944), IL1F10 (rs3811058) and IL1RN (rs419598, the IL1RA VNTR, rs315952 and rs315951) were genotyped in 2675 AS cases and 2592 healthy controls recruited in 12 different centres in 10 countries. Association of variants with AS was tested by Mantel-Haenszel random effects analysis.

RESULTS

Strong association was observed with three single nucleotide polymorphisms (SNPs) in the IL1A gene (rs2856836, rs17561, rs1894399, p = 0.0036, 0.000019 and 0.0003, respectively). There was no evidence of significant heterogeneity of effects between centres, and no evidence of non-combinability of findings. The population attributable risk fraction of these variants in Caucasians is estimated at 4-6%.

CONCLUSIONS

This study confirms that IL1A is associated with susceptibility to AS. Association of the other IL1 gene complex members could not be excluded in specific populations. Prospective meta-analysis is a useful tool in confirmation studies of genes associated with complex genetic disorders such as AS, providing sufficiently large sample sizes to produce robust findings often not achieved in smaller individual cohorts.

OBJECTIVE

To investigate the contribution of pepsin to inflammation attributed to nonacidic gastric reflux via analysis of inflammatory cytokine and cytokine receptor gene expression in pepsin-treated human hypopharyngeal epithelial cells in vitro.

METHODS

Translational research.

METHODS

This study was performed in an academic research laboratory.

METHODS

Human hypopharyngeal epithelial cells were incubated with or without pepsin (0.1 mg/mL) at pH 7.4, 37 degrees C, overnight. Expression of 84 inflammatory cytokines and cytokine receptors was analyzed via RT(2) qPCR array.

RESULTS

Expression of a number of inflammatory cytokines and receptors was altered in human hypopharyngeal epithelial cells following overnight treatment with pepsin at neutral pH. Greater than 1.5-fold change in gene expression was detected for CCL20, CCL26, IL8, IL1F10, IL1A, IL5, BCL6, CCR6, and CXCL14 (P < 0.05).

CONCLUSIONS

Exposure of hypopharyngeal cells to pepsin in a nonacidic environment induces the expression of several pro-inflammatory cytokines and receptors, including those known to be involved in inflammation of esophageal epithelium in response to reflux and which contribute to the pathophysiology of reflux esophagitis. These data indicate that refluxed pepsin may contribute to laryngeal inflammation associated with nonacidic gastric reflux, including that experienced by patients despite maximal acid suppression therapy.

Genes in the interleukin-1 (IL-1) gene cluster on human chromosome 2 play an important role in mediating inflammatory responses and are associated with numerous diseases. We have identified a novel IL-1-like gene, IL-1F10, on human chromosome 2q13-14.1 near the IL-1 receptor antagonist gene (IL-1RN). The IL1F10 gene is encoded by 5 exons spanning over 7.8 kb of genomic DNA. The 1008-bp IL-1F10 cDNA encodes a 152-amino acid protein that shares between 41% and 43% amino acid identity with human IL-1 receptor antagonist (IL-1Ra) and FIL-1delta, respectively. IL-1F10 shares characteristics of the IL-1Ra family, including key amino acid consensus sequences and a similar genomic structure. By multitissue first-strand cDNA PCR analysis, IL-1F10 mRNA is expressed in heart, placenta, fetal liver, spleen, thymus, and tonsil. The expression in a variety of immune tissues and similarity to IL-1Ra suggest a role of IL-1F10 in the inflammatory response.

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease of unknown etiology. Among cytokines induced in UC, interleukin 1 antagonist (IL-1ra) and interleukin 1 β (IL-1β) seems to have a central role because of its immunoregulatory and proinflammatory activities.

OBJECTIVE

To determine the association between IL-1RA and IL-1B gene polymorphisms and the clinical features of UC in the Mexican Mestizo population.

METHODS

Five polymorphisms in the IL-1 gene cluster members IL-1B (rs16944), IL1F10 (rs3811058), and IL-1RN (rs419598, rs315952, and rs315951) were genotyped by 5' exonuclease TaqMan genotyping assays in a group of 200 Mexican patients with UC and 248 ethnically matched unrelated healthy controls.

RESULTS

We found a significant increased frequencies of IL-1RN6/1 TC (rs315952) and RN6/2 CC (rs315951) and decreased frequency of IL-1B-511 TC (rs16944) genotypes in UC patients as compared with healthy controls. In the subgroup analysis, we found a significant association between the RN6/2 GG (rs315951) and IL-1B-511 CC (rs16944) genotypes and the presence of steroid-dependence in UC patients (pC=00001, OR=15.6 and pC=0.008, OR=4.09, respectively). Patients with UC showed increased frequencies of IL-1RN "CTC" and "TCG" haplotypes when compared with healthy controls (P=0.019, OR=1.43 and P<10(-7), OR=2.63, respectively). Two haplotypes (TTG and CTG) showed decreased frequency in patients when compared with healthy controls (P=9×10(-7), OR=0.11 and P=8×10(-6), OR=0.11, respectively).

CONCLUSIONS

IL-1 RN and IL-1B polymorphisms were associated with the genetic susceptibility to develop UC and might be associated with the presence of steroid-dependence in UC patients.

OBJECTIVE

The majority of genome-wide association studies (GWAS) of stroke have focused on European-ancestry populations; however, none has been conducted in African Americans, despite the disproportionately high burden of stroke in this population. The Consortium of Minority Population Genome-Wide Association Studies of Stroke (COMPASS) was established to identify stroke susceptibility loci in minority populations.

METHODS

Using METAL, we conducted meta-analyses of GWAS in 14 746 African Americans (1365 ischemic and 1592 total stroke cases) from COMPASS, and tested genetic variants with P<10(-6) for validation in METASTROKE, a consortium of ischemic stroke genetic studies in European-ancestry populations. We also evaluated stroke loci previously identified in European-ancestry populations.

RESULTS

The 15q21.3 locus linked with lipid levels and hypertension was associated with total stroke (rs4471613; P=3.9×10(-8)) in African Americans. Nominal associations (P<10(-6)) for total or ischemic stroke were observed for 18 variants in or near genes implicated in cell cycle/mRNA presplicing (PTPRG, CDC5L), platelet function (HPS4), blood-brain barrier permeability (CLDN17), immune response (ELTD1, WDFY4, and IL1F10-IL1RN), and histone modification (HDAC9). Two of these loci achieved nominal significance in METASTROKE: 5q35.2 (P=0.03), and 1p31.1 (P=0.018). Four of 7 previously reported ischemic stroke loci (PITX2, HDAC9, CDKN2A/CDKN2B, and ZFHX3) were nominally associated (P<0.05) with stroke in COMPASS.

CONCLUSIONS

We identified a novel genetic variant associated with total stroke in African Americans and found that ischemic stroke loci identified in European-ancestry populations may also be relevant for African Americans. Our findings support investigation of diverse populations to identify and characterize genetic risk factors, and the importance of shared genetic risk across populations.

OBJECTIVE

Knowledge of interleukin-38 (IL-38), formerly IL-1 family member 10, is sparse, but Il1f10 polymorphisms are associated with inflammatory diseases, and recombinant IL-38 inhibits inflammatory responses similar to those reported in the context of systemic lupus erythematosus (SLE). We undertook this study to explore the function of endogenous IL-38 in human peripheral blood mononuclear cells (PBMCs) as well as its abundance in serum in a well-characterized cohort of SLE patients.

METHODS

Serum IL-38 and IL-10 levels were quantified by enzyme-linked immunosorbent assay in 142 SLE patients at ≤3 consecutive visits and in 28 healthy volunteers. To assess IL-38 function, we silenced IL-38 in PBMCs from healthy donors using IL-38 small interfering RNA (siRNA).

RESULTS

IL-38 (63-5,928 pg/ml) was detectable in 16% of 372 serum samples. IL-38 abundance was significantly higher in samples from SLE patients than in samples from healthy controls (P = 0.004) and 11-fold higher in patients with active disease (SLE Disease Activity Index 2000 [SLEDAI-2K] score of ≥4) than in those with inactive disease (SLEDAI-2K score of <4) (P = 0.044). Importantly, IL-38 detection was associated with increased risk of renal lupus (relative risk [RR] 1.6, P = 0.027) and central nervous system lupus (RR 2.3, P = 0.034), and detectable baseline IL-38 entailed a 1.6-fold increased risk of subsequently meeting criteria for persistently active disease (P = 0.0097). Longitudinal time-adjusted mean IL-38 concentration was also 6-fold higher in patients with persistently active disease than in those without (P = 0.023). Remarkably, PBMCs treated with IL-38 siRNA produced up to 28-fold more of the proinflammatory mediators IL-6, CCL2, and APRIL than did control siRNA-transfected cells upon stimulation with Toll-like receptor agonists. Similarly, in SLE patients, the antiinflammatory cytokine IL-10 was 5-fold more abundant when IL-38 was detectable.

CONCLUSIONS

This is the first study of the function of endogenous IL-38, and the data suggest that IL-38 may be protective in SLE. A strong association between IL-38 and SLE severity suggests that IL-38 expression is driven by processes linked to SLE pathogenesis. Exploitation of the regulatory effects of IL-38 may represent a promising therapeutic strategy in SLE.

The homeostasis of the epidermis depends on keratinocyte differentiation and cornification, a mode of programmed cell death that does not elicit inflammation. Here, we report that cornification is associated with the expression of specific genes that control multiple steps of pyroptosis, another form of cell death that involves the processing and release of interleukin-1 family (IL1F) cytokines. Expression levels of pro-inflammatory IL1A and IL1B and of the pyroptotic pore-forming gasdermin (GSDM) D were downregulated during terminal differentiation of human keratinocytes in vitro. By contrast, negative regulators of IL-1 processing, including NLR family pyrin domain containing 10 (NLRP10) and pyrin domain-containing 1 (PYDC1), the anti-inflammatory IL1F members IL-37 (IL1F7) and IL-38 (IL1F10), and GSDMA, were strongly induced in differentiated keratinocytes. In human tissues, these keratinocyte differentiation-associated genes are expressed in the skin at higher levels than in any other organ, and mammalian species, that have lost the epidermal cornification program during evolution, i.e. whales and dolphins, lack homologs of these genes. Together, our results suggest that human epidermal cornification is accompanied by a tight control of pyroptosis and warrant further studies of potential defects in the balance between cornification and pyroptosis in skin pathologies.

The proinflammatory cytokine interleukin (IL)-1β is implicated in the development of insulin resistance and β-cell dysfunction, whereas higher circulating levels of IL-1 receptor antagonist (IL-1RA), an endogenous inhibitor of IL-1β, has been suggested to improve glycemia and β-cell function in patients with type 2 diabetes. To elucidate the protective role of IL-1RA, this study aimed to identify genetic determinants of circulating IL-1RA concentration and to investigate their associations with immunological and metabolic variables related to cardiometabolic risk. In the analysis of seven discovery and four replication cohort studies, two single nucleotide polymorphisms (SNPs) were independently associated with circulating IL-1RA concentration (rs4251961 at the IL1RN locus [n = 13,955, P = 2.76 × 10(-21)] and rs6759676, closest gene locus IL1F10 [n = 13,994, P = 1.73 × 10(-17)]). The proportion of the variance in IL-1RA explained by both SNPs combined was 2.0%. IL-1RA-raising alleles of both SNPs were associated with lower circulating C-reactive protein concentration. The IL-1RA-raising allele of rs6759676 was also associated with lower fasting insulin levels and lower HOMA insulin resistance. In conclusion, we show that circulating IL-1RA levels are predicted by two independent SNPs at the IL1RN and IL1F10 loci and that genetically raised IL-1RA may be protective against the development of insulin resistance.

Interleukins (ILs) are key mediators of the immune response and inflammatory process. Plasma levels of IL-10, IL-1Ra, and IL-6 are associated with metabolic conditions, show large inter-individual variations, and are under strong genetic control. Therefore, elucidation of the genetic variants that influence levels of these ILs provides useful insights into mechanisms of immune response and pathogenesis of diseases. We conducted a genome-wide association study (GWAS) of IL-10, IL-1Ra, and IL-6 levels in 707 non-diabetic African Americans using 5,396,780 imputed and directly genotyped single nucleotide polymorphisms (SNPs) with adjustment for gender, age, and body mass index. IL-10 levels showed genome-wide significant associations (p < 5 × 10(-8)) with eight SNPs, the most significant of which was rs5743185 in the PMS1 gene (p = 2.30 × 10(-10)). We tested replication of SNPs that showed genome-wide significance in 425 non-diabetic individuals from West Africa, and successfully replicated rs17365948 in the YWHAZ gene (p = 0.02). IL-1Ra levels showed suggestive associations with two SNPs in the ASB3 gene (p = 2.55 × 10(-7)), ten SNPs in the IL-1 gene family (IL1F5, IL1F8, IL1F10, and IL1Ra, p = 1.04 × 10(-6) to 1.75 × 10(-6)), and 23 SNPs near the IL1A gene (p = 1.22 × 10(-6) to 1.63 × 10(-6)). We also successfully replicated rs4251961 (p = 0.009); this SNP was reported to be associated with IL-1Ra levels in a candidate gene study of Europeans. IL-6 levels showed genome-wide significant association with one SNP (RP11-314E23.1; chr6:133397598; p = 8.63 × 10(-9)). To our knowledge, this is the first GWAS on IL-10, IL-1Ra, and IL-6 levels. Follow-up of these findings may provide valuable insight into the pathobiology of IL actions and dysregulations in inflammation and human diseases.

Pleiotropic genetic variants have independent effects on different phenotypes. C-reactive protein (CRP) is associated with several cardiometabolic phenotypes. Shared genetic backgrounds may partially underlie these associations. We conducted a genome-wide analysis to identify the shared genetic background of inflammation and cardiometabolic phenotypes using published genome-wide association studies (GWAS). We also evaluated whether the pleiotropic effects of such loci were biological or mediated in nature. First, we examined whether 283 common variants identified for 10 cardiometabolic phenotypes in GWAS are associated with CRP level. Second, we tested whether 18 variants identified for serum CRP are associated with 10 cardiometabolic phenotypes. We used a Bonferroni corrected p-value of 1.1×10-04 (0.05/463) as a threshold of significance. We evaluated the independent pleiotropic effect on both phenotypes using individual level data from the Women Genome Health Study. Evaluating the genetic overlap between inflammation and cardiometabolic phenotypes, we found 13 pleiotropic regions. Additional analyses showed that 6 regions (APOC1, HNF1A, IL6R, PPP1R3B, HNF4A and IL1F10) appeared to have a pleiotropic effect on CRP independent of the effects on the cardiometabolic phenotypes. These included loci where individuals carrying the risk allele for CRP encounter higher lipid levels and risk of type 2 diabetes. In addition, 5 regions (GCKR, PABPC4, BCL7B, FTO and TMEM18) had an effect on CRP largely mediated through the cardiometabolic phenotypes. In conclusion, our results show genetic pleiotropy among inflammation and cardiometabolic phenotypes. In addition to reverse causation, our data suggests that pleiotropic genetic variants partially underlie the association between CRP and cardiometabolic phenotypes.

OBJECTIVE

Spondyloarthritis is a group of articular disorders sharing a genetic background. Polymorphisms in the IL-1 gene cluster have previously been associated with ankylosing spondylitis (AS), a subset of spondyloarthritis. This study examined the association between several of these polymorphisms and the whole spondyloarthritis. Particular attention was devoted to genotype-phenotype correlations.

METHODS

Seven single-nucleotide polymorphisms (SNP) and a variable number tandem repeat located in the IL-1 gene cluster were genotyped in 185 independent spondyloarthritis trios. Family-based association test (FBAT) was computed using the FBAT software. Analysis was carried in spondyloarthritis as a whole and also in AS. A case-control replication study was performed for four of the SNP, in an independent sample of 414 spondyloarthritis and 264 controls. A combined analysis of both studies was performed.

RESULTS

The SNP rs2856836 in IL1A was significantly associated with spondyloarthritis (p=0.009) and AS (p=0.010) in the family study. The case-control study revealed an association between another IL1A variant (rs1894399) and AS (p=0.035), and between IL1F10.3 (rs3811058) and spondyloarthritis (p=0.041). By combining family and case-control studies an association between AS and IL1A was confirmed (rs1894399, p=0.024), whereas non-AS was more significantly associated with IL1F10.3 (p=0.0043). Family-based and case-control studies revealed significant association between the two most frequent haplotypes combining the four SNP of the replication study and both spondyloarthritis (p=0.0054 and p=0.038) and AS phenotypes (p=0.018 and 0.0036).

CONCLUSIONS

This study is the first to demonstrate an association between several polymorphisms located in the IL-1 gene cluster and spondyloarthritis as a whole. The IL1A locus was strongly associated with AS phenotype, whereas IL1F10 was associated with non-AS.

BACKGROUND

C-reactive protein (CRP) levels are associated with cardiovascular disease and systemic inflammation. We assessed whether CRP-associated loci were associated with serum CRP and retinal markers of microvascular disease, in Asian populations.

METHODS

Genome-wide association analysis (GWAS) for serum CRP was performed in East-Asian Chinese (N = 2,434) and Malays (N = 2,542) and South-Asian Indians (N = 2,538) from Singapore. Leveraging on GWAS data, we assessed, in silico, association levels among the Singaporean datasets for 22 recently identified CRP-associated loci. At loci where directional inconsistencies were observed, quantification of inter-ethnic linkage disequilibrium (LD) difference was determined. Next, we assessed association for a variant at CRP and retinal vessel traits [central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE)] in a total of 24,132 subjects of East-Asian, South-Asian and European ancestry.

RESULTS

Serum CRP was associated with SNPs in/near APOE, CRP, HNF1A and LEPR (p-values ≤4.7×10(-8)) after meta-analysis of Singaporean populations. Using a candidate-SNP approach, we further replicated SNPs at 4 additional loci that had been recently identified to be associated with serum CRP (IL6R, GCKR, IL6 and IL1F10) (p-values ≤0.009), in the Singaporean datasets. SNPs from these 8 loci explained 4.05% of variance in serum CRP. Two SNPs (rs2847281 and rs6901250) were detected to be significant (p-value ≤0.036) but with opposite effect directions in the Singaporean populations as compared to original European studies. At these loci we did not detect significant inter-population LD differences. We further did not observe a significant association between CRP variant and CRVE or CRAE levels after meta-analysis of all Singaporean and European datasets (p-value >0.058).

CONCLUSIONS

Common variants associated with serum CRP, first detected in primarily European studies, are also associated with CRP levels in East-Asian and South-Asian populations. We did not find a causal link between CRP and retinal measures of microvascular disease.

OBJECTIVE

The interleukin (IL)-1 family and its related family members are primary inflammatory cytokines. The aim of this study was to assess the possible association between nine IL-1 family gene polymorphisms and rheumatoid arthritis (RA).

METHODS

To investigate the genetic association between IL-1 family gene polymorphisms and the risk of RA in a Korean population, 69 single nucleotide polymorphisms (SNPs) of the nine IL-1 family gene regions were selected. A total of 806 subjects (498 controls and 308 RA patients) were included in the study. The genotypes of the selected SNPs in the IL-1 family genes were determined using Illumina Sentrix Array Matrix chips. SNP Stats, Haploview, and SNP Analyzer, and Helixtree programs were used for the analysis of the genetic data.

RESULTS

We observed statistically significant associations between the SNPs of IL1F10 and IL1RN among the IL-1 family genes in the RA patients and the control population. When the patients were divided into two groups according to the parameters of disease activity, including C-reactive protein (CRP) level >> or = 0.5 or < 0.5 mg/dL), the erythrocyte sedimentation rate (ESR) >> or = 30 or < 30 mm/h), and parameters of severity, including rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and bone erosion (positive or not), we found significant associations between the parameters, including CRP, ESR, and bone erosion, and SNPs of the IL-1 family genes in RA.

CONCLUSIONS

This study suggests that IL-1 family gene (IL1F10 and IL1RN) polymorphisms may play an important role in the susceptibility to developing RA.

We have previously established that recombinant CD47 can ameliorate the inflammatory response to synthetic polymeric surfaces. Here, we begin to profile, at the transcriptional, translational and cell signaling level, the inflammatory cell response when blood interacts with CD47 modified polyvinyl chloride (PVC) (CD47-PVC). We used qPCR arrays to compare transcriptional changes between human whole blood exposed to CD47-PVC or PVC. Transcription of IL1F5, IL1F10, IL17F, CCL3, CCL8, CCL28, CXCL12, and CXCL13 was upregulated in blood exposed to PVC, compared to CD47-PVC. The increase in CCL3 and CCL8 transcription correlated with an increase in the chemokines' presence in the plasma. Exposure of blood to CD47-PVC resulted in an increase, compared to PVC, in transcription of CCL2, CCL4, CCL20, CXCL1, TGFβ3, GDF3, GDF10, CD40LG, and TNFSF10. CD47-PVC exposure resulted in an increase of the following matrix metalloproteinase related genes: MMP1, MMP7, MMP13, and MMP16. Phosflow cytometry, and assays examining transcription factor binding, cell attachment, and genome-wide chromatin association indicated that members of the JAK-STAT signaling pathway, particularly JAK2 and STAT5, mediate inflammatory cell interactions with CD47-PVC. Our data demonstrate that differential molecular responses to CD47 involve downregulation of cytokines, upregulation of MMPs, and JAK/STAT signaling mechanisms.

BACKGROUND

Cytokines are a group of polypeptides with an important role in the inflammatory response. It has been suggested that certain polymorphisms located in several cytokine genes are associated with different diseases. The aim of the present study was to establish the gene frequency of 13 polymorphisms of the IL-1RN, IL-6, IL-10, INF-γ, and TNF-α genes in a Mexican population. These polymorphisms have been reported in several populations, with important variation in frequency according to the studied population.

METHODS

Thirteen polymorphisms (rs419598, rs315951, rs2234663, rs3811058, rs1800796, rs2069827, rs1800896, rs1800871, rs1800872, rs1800629, rs2069709, rs2069710, and rs361525) were analyzed by 5' exonuclease TaqMan genotyping assays in a group of 248 healthy unrelated Mexican individuals.

RESULTS

The results obtained showed that the studied Mexican population presents significant differences (p<0.05) in the distribution of the IL1RN (rs419598, rs315951, and and rs2234663), IL1F10 (rs3811058), IL6 (rs1800796, rs2069827), IL10 (rs1800896, rs1800871, and rs1800872), and TNF-α (rs1800629) polymorphisms when compared to Caucasian, Asian, and African populations.

CONCLUSIONS

In summary, the distribution of the IL-1RN, IL-6, IL-10, and TNF-α cytokine gene polymorphisms distinguishes the studied Mexican population from other groups. Since the alleles of these cytokines are associated with the development of several inflammatory diseases, knowledge of the distribution of these alleles in the studied Mexican population could be helpful to understand their true role as a genetic susceptibility marker in this population.

An effective countermeasure against radiation damage to normal tissues is urgently needed. The major goal of the present study was to determine if minocycline could modify the immunomodulatory effects of radiation on the brain. C57BL/6 mice were treated with minocycline intraperitoneally for 5 days beginning immediately before total-body exposure to 0, 1, 2 and 3 Gray (Gy) (60)Co γ-rays. Brains were collected on days 4 and 32 post-irradiation for cytokine and gene analyses. Minocycline treatment significantly increased the levels of interleukin (IL)-10, IL-15 and vascular endothelial growth factor (VEGF) in the brain on day 4 in one or more irradiated groups compared to radiation-alone (p<0.05). IL-10 is anti-inflammatory, IL-15 can prevent apoptosis and VEGF is nuroprotective. On day 32, the drug decreased IL-1β in the 2- Gy group (p<0.05 vs. 2-Gy alone); this cytokine is implicated in immune-related central nervous system pathologies. Microarray analysis of brains on day 32 showed that while radiation increased expression of inflammatory genes such as Il1f10, Il17, Tnfrsf11b, Tnfsf12, Il12b and Il1f8, these were no longer up-regulated in the minocycline-treated groups. Similarly, the pro-apoptotic gene Bik and nitric oxide synthase producer (Nostrin) were no longer up-regulated in the drug-treated groups. Pathway analysis based on gene data suggested that catenin-β1 and tumor suppressor-related transcription regulation were significantly activated by radiation and/or minocycline (activation z-score >2.0). Overall, the data warrant further testing of minocycline as a potential neuroprotectant against radiation-induced damage.

BACKGROUND

Chlamydia pneumoniae heat shock protein (HSP) 60 is known to contribute to the activation of inflammation. In addition, there are contradictory reports on C. pneumoniae and their role in activation of pathways (apoptotic/antiapoptotic/necrosis) in coronary artery disease (CAD). Hence, more studies are required to know the actual role of C. pneumoniae in activation of apoptotic/antiapoptotic/necrosis pathways.

RESULTS

In this study, two sets of patient groups (cHSP60 positive and cHSP60 negative) were included and gene expression was studied by cDNA micro array and real time polymerase chain reaction arrays. Expression of Caspase-3, 8, 9, c-FLIP, PPAR-γ, PGC-1α, and Gsk-3b were also evaluated at protein level by immunoblotting. In cHSP60 positive CAD patients significantly higher (p<0.001) mRNA expression was found for CCL4, CXCL4, CXCL9, IL-8, CD40LG, CD8, TGFβ1, TGFβ2, APOE, EGR1, CTGF, APOB, LDLR, LPA, and LPL, whereas significantly lower (p<0.001) mRNA expression was detected for CD4, IL1F10, IFNA2, and IL-10 as compared to cHSP60 negative CAD patients. Additionally, at protein level expression of Caspase-3 (p=0.027), 8 (p=0.028), and 9 (p=0.037) were higher and c-FLIP (p=0.028) and PPAR-γ (p=0.95) expression were comparable in cHSP60 positive CAD patients compared to cHSP60 negative CAD patients.

CONCLUSIONS

Genes/proteins of pre-apoptotic caspase dependent/independent pathways, chemokines, and inflammatory cytokines receptors were significantly up-regulated in human atheromatous plaques of cHSP60 positive CAD patients suggesting an association of cHSP60 with CAD.

Association between elevated C-reactive protein (CRP) serum levels and subclinical atherosclerosis and cardiovascular (CV) events was described in rheumatoid arthritis (RA). CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 exert an influence on elevated CRP serum levels in non-rheumatic Caucasians. Consequently, we evaluated the potential role of these genes in the development of CV events and subclinical atherosclerosis in RA patients. Three tag CRP polymorphisms and HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were genotyped in 2,313 Spanish patients by TaqMan. Subclinical atherosclerosis was determined in 1,298 of them by carotid ultrasonography (by assessment of carotid intima-media thickness-cIMT-and presence/absence of carotid plaques). CRP serum levels at diagnosis and at the time of carotid ultrasonography were measured in 1,662 and 1,193 patients, respectively, by immunoturbidimetry. Interestingly, a relationship between CRP and CRP serum levels at diagnosis and at the time of the carotid ultrasonography was disclosed. However, no statistically significant differences were found when CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were evaluated according to the presence/absence of CV events, carotid plaques and cIMT after adjustment. Our results do not confirm an association between these genes and CV disease in RA.

The IL-1 family member IL-38 (IL1F10) suppresses inflammatory and autoimmune conditions. Here, we report that plasma concentrations of IL-38 in 288 healthy Europeans correlate positively with circulating memory B cells and plasmablasts. IL-38 correlated negatively with age (P = 0.02) and was stable in 48 subjects for one year. In comparison with primary keratinocytes, IL1F10 expression in CD19⁺ B cells from PBMC was lower, whereas cell-associated IL-38 expression was comparable. In vitro, IL-38 is released from CD19⁺ B cells after stimulation with Rituximab. Intravenous LPS in humans failed to induce circulating IL-38, compared to 100-fold induction in IL-6 and IL-1 Receptor antagonist. In a cohort of 296 subjects with BMI>27 at high risk for cardiovascular disease, IL-38 plasma concentrations were significantly lower than in healthy subjects (P <0.0001), and lowest in those with metabolic syndrome (P <0.05). IL-38 also correlated inversely with hsCRP (P <0.01), IL-6, IL-1Ra and leptin (P <0.05). We conclude that a relative deficiency of the B-cell product IL-38 is associated with increased systemic inflammation in aging, cardiovascular and metabolic disease, and is consistent with IL-38 as an anti-inflammatory cytokine. This article is protected by copyright. All rights reserved.

Keywords: B cells; IL-38; Inflammation; Obesity; cardiovascular disease risk.

In our recent clinical trial, increased peripheral concentrations of pro-inflammatory molecular mediators were determined in complex regional pain syndrome (CRPS) patients. After 3 months adjunctive unilateral, selective L4 dorsal root ganglion stimulation (L4-DRG_STIM), significantly decreased serum IL-10 and increased saliva oxytocin levels were assessed along with an improved pain and functional state. The current study extended molecular profiling towards gene expression analysis of genes known to be involved in the gonadotropin releasing hormone receptor and neuroinflammatory (cytokines/chemokines) signaling pathways.

Blood samples were collected from 12 CRPS patients for whole-transcriptome profiling in order to assay 18,845 inflammation-associated genes from frozen blood at baseline and after 3 months L4-DRG_STIM using PANTHER™ pathway enrichment analysis tool.

Pathway enrichment analyses tools (GOrilla™ and PANTHER™) showed predominant involvement of inflammation mediated by chemokines/cytokines and gonadotropin releasing hormone receptor pathways. Further, screening of differentially regulated genes showed changes in innate immune response related genes. Transcriptomic analysis showed that 21 genes (predominantly immunoinflammatory) were significantly changed after L4-DRG_STIM. Seven genes including TLR1, FFAR2, IL1RAP, ILRN, C5, PKB and IL18 were down regulated and fourteen genes including CXCL2, CCL11, IL36G, CRP, SCGB1A1, IL-17F, TNFRSF4, PLA2G2A, CREB3L3, ADAMTS12, IL1F10, NOX1, CHIA and BDKRB1 were upregulated.

In our sub-group analysis of L4-DRG_STIM treated CRPS patients, we found either upregulated or downregulated genes involved in immunoinflammatory circuits relevant for the pathophysiology of CRPS indicating a possible relation. However, large biobank-based approaches are recommended to establish genetic phenotyping as a quantitative outcome measure in CRPS patients. Trial registration The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267.

Trained immunity is the acquisition of a hyperresponsive phenotype by innate immune cells (such as monocytes and macrophages) after an infection or vaccination, a de facto nonspecific memory dependent on epigenetic and metabolic reprogramming of these cells. We have recently shown that induction of trained immunity is dependent on IL-1β. Here, we show that recombinant IL-38, an anti-inflammatory cytokine of the IL-1-family, was able to induce long-term inhibitory changes and reduce the induction of trained immunity by β-glucan in vivo in C57BL/6 mice and ex vivo in their bone marrow cells. IL-38 blocked mTOR signaling and prevented the epigenetic and metabolic changes induced by β-glucan. In healthy subjects, the IL1F10 associated single nucleotide polymorphism rs58965312 correlated with higher plasma IL-38 concentrations and reduced induction of trained immunity by β-glucan ex vivo. These results indicate that IL-38 induces long-term anti-inflammatory changes and also inhibits the induction of trained immunity. Recombinant IL-38 could therefore potentially be used as a therapeutic intervention for diseases characterized by exacerbated trained immunity.

Keywords: burn; ethanol; inflammation; small RNAs.