Identification of a novel regulatory region in the interleukin-6 gene promoter

TNF-α/Stearate Induced H3K9/18 Histone Acetylation Amplifies IL-6 Expression in 3T3-L1 Mouse Adipocytes

Extensive evidence supports the connection between obesity-induced inflammation and the heightened expression of IL-6 adipose tissues. However, the mechanism underlying the IL-6 exacerbation in the adipose tissue remains unclear. There is general agreement that TNF-α and stearate concentrations are mildly elevated in adipose tissue in the state of obesity. We hypothesize that TNF-α and stearate co-treatment induce the increased expression of IL-6 in mouse adipocytes. We therefore aimed to determine IL-6 gene expression and protein production by TNF-α/stearate treated adipocytes and investigated the mechanism involved. To test our hypothesis, 3T3-L1 mouse preadipocytes were treated with TNF-α, stearate, or TNF-α/stearate. IL-6 gene expression was assessed by quantitative real-time qPCR. IL-6 protein production secreted in the cell culture media was determined by ELISA. Acetylation of histone was analyzed by Western blotting. Il6 region-associated histone H3 lysine 9/18 acetylation (H3K9/18Ac) was determined by ChIP-qPCR. 3T3-L1 mouse preadipocytes were co-challenged with TNF-α and stearate for 24 h, which led to significantly increased IL-6 gene expression (81 ± 2.1 Fold) compared to controls stimulated with either TNF-α (38 ± 0.5 Fold; p = 0.002) or stearate (56 ± 2.0 Fold; p = 0.013). As expected, co-treatment of adipocytes with TNF-α and stearate significantly increased protein production (338 ± 11 pg/mL) compared to controls stimulated with either TNF-α (28 ± 0.60 pg/mL; p = 0.001) or stearate (53 ± 0.20 pg/mL, p = 0.0015). Inhibition of histone acetyltransferases (HATs) with anacardic acid or curcumin significantly reduced the IL-6 gene expression and protein production by adipocytes. Conversely, TSA-induced acetylation substituted the stimulatory effect of TNF-α or stearate in their synergistic interaction for driving IL-6 gene expression and protein production. Mechanistically, TNF-α/stearate co-stimulation increased the promoter-associated histone H3 lysine 9/18 acetylation (H3K9/18Ac), rendering a transcriptionally permissive state that favored IL-6 expression at the transcriptional and translational levels. Our data represent a TNF-α/stearate cooperativity model driving IL-6 expression in 3T3-L1 cells via the H3K9/18Ac-dependent mechanism, with implications for adipose IL-6 exacerbations in obesity.

The Il6 -39 kb enhancer containing clustered GATA2- and PU.1-binding sites is essential for Il6 expression in murine mast cells

Mast cells serve as a first-line defense of innate immunity. Interleukin-6 (IL-6) induced by bacterial lipopolysaccharide (LPS) in mast cells plays a crucial role in antibacterial protection. The zinc finger transcription factor GATA2 cooperatively functions with the ETS family transcription factor PU.1 in multiple mast cell activities. However, the regulatory landscape directed by GATA2 and PU.1 under inflammation remains elusive. We herein showed that a large proportion of GATA2-binding peaks were closely located with PU.1-binding peaks in distal cis-regulatory regions of inflammatory cytokine genes in mast cells. Notably, GATA2 and PU.1 played crucial roles in promoting LPS-mediated inflammatory cytokine production. Genetic ablation of GATA2-PU.1-clustered binding sites at the Il6 -39 kb region revealed its central role in LPS-induced Il6 expression in mast cells. We demonstrate a novel collaborative activity of GATA2 and PU.1 in cytokine induction upon inflammatory stimuli via the GATA2-PU.1 overlapping sites in the distal cis-regulatory regions.

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GATA2- and PU.1-binding peaks are closely located in distal enhancers of cytokine genes

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GATA2 and PU.1 play crucial roles in promoting LPS-mediated cytokine induction

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The Il6 -39 kb enhancer containing GATA2 and PU.1 motifs are crucial for Il6 induction

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GATA2 inhibitor exerts anti-inflammatory effects via reducing cytokine induction

Genetic variants affecting chemical mediated skin immunotoxicity

The skin is an immune-competent organ and this function may be impaired by exposure to chemicals, which may ultimately result in immune-mediated dermal disorders. Interindividual variability to chemical-induced skin immune reactions is associated with intrinsic individual characteristics and their genomes. In the last 30-40 years, several genes influencing susceptibility to skin immune reactions were identified. The aim of this review is to provide information regarding common genetic variations affecting skin immunotoxicity. The polymorphisms selected for this review are related to xenobiotic-metabolizing enzymes (CYPA1 and CYPB1 genes), antioxidant defense (GSTM1, GSTT1, and GSTP1 genes), aryl hydrocarbon receptor signaling pathway (AHR and ARNT genes), skin barrier function transepidermal water loss (FLG, CASP14, and SPINK5 genes), inflammation (TNF, IL10, IL6, IL18, IL31, and TSLP genes), major histocompatibility complex (MHC) and neuroendocrine system peptides (CALCA, TRPV1, ACE genes). These genes present variants associated with skin immune responses and diseases, as well as variants associated with protecting skin immune homeostasis following chemical exposure. The molecular and association studies focusing on these genetic variants may elucidate their functional consequences and contribution in the susceptibility to skin immunotoxicity. Providing information on how genetic variations affect the skin immune system may reduce uncertainties in estimating chemical hazards/risks for human health in the future.

Perioperative inhibition of β-adrenergic and COX2 signaling in a clinical trial in breast cancer patients improves tumor Ki-67 expression, serum cytokine levels, and PBMCs transcriptome

Catecholamines and prostaglandins are secreted abundantly during the perioperative period in response to stress and surgery, and were shown by translational studies to promote tumor metastasis. Here, in a phase-II biomarker clinical trial in breast cancer patients (n = 38), we tested the combined perioperative use of the β-blocker, propranolol, and the COX2-inhibitor, etodolac, scheduled for 11 consecutive perioperative days, starting 5 days before surgery. Blood samples were taken before treatment (T1), on the mornings before and after surgery (T2&T3), and after treatment cessation (T4). Drugs were well tolerated. Results based on a-priori hypotheses indicated that already before surgery (T2), serum levels of pro-inflammatory IL-6, CRP, and IFNγ, and anti-inflammatory, cortisol and IL-10, increased. At T2 and/or T3, drug treatment reduced serum levels of the above pro-inflammatory cytokines and of TRAIL, as well as activity of multiple inflammation-related transcription factors (including NFκB, STAT3, ISRE), but not serum levels of cortisol, IL-10, IL-18, IL-8, VEGF and TNFα. In the excised tumor, treatment reduced the expression of the proliferation marker Ki-67, and positively affected its transcription factors SP1 and AhR. Exploratory analyses of transcriptome modulation in PBMCs revealed treatment-induced improvement at T2/T3 in several transcription factors that in primary tumors indicate poor prognosis (CUX1, THRa, EVI1, RORa, PBX1, and T3R), angiogenesis (YY1), EMT (GATA1 and deltaEF1/ZEB1), proliferation (GATA2), and glucocorticoids response (GRE), while increasing the activity of the oncogenes c-MYB and N-MYC. Overall, the drug treatment may benefit breast cancer patients through reducing systemic inflammation and pro-metastatic/pro-growth biomarkers in the excised tumor and PBMCs.

Association between IL4, IL6 gene polymorphism and lumbar disc degeneration in Chinese population

Lumbar disc disease (LDD) is a common musculoskeletal disorder, caused by degeneration of intervertebral discs of the lumbar spine and is one of the most common musculoskeletal disorders affliction in adult. There is growing evidence that LDD has strong genetic determinants. We analyze whether the IL4 and IL6 gene polymorphism is related to LDD in Chinese Han population. The participants were 498 with LDD and 463 without LDD. IL4 and IL6 gene polymorphism were determined by Sequenom MassARRAY. We found that SNPs rs1800796(OR = 1.29, 95% CI, 1.07 – 1.57, p = 0.009), rs1524107(OR = 1.28, 95% CI, 1.05 – 1.55, p = 0.013), rs2069840 (OR = 1.39, 95% CI, 1.03 – 1.89, p = 0.033) in IL6 gene were significantly associated with LDD risk at a 5% level. In addition, genetic models found IL4 gene (rs2243250) were associated with LDD. In this study, we analyzed and associated SNPs of IL4 and IL6 with LDD risk. In summary, four variations (rs1800796, rs1524107, rs2069840, rs2243250) of the selected candidate SNPs were associated with susceptibility to LDD in our study. The results of this study have the guiding significance in clinical work in the future in the treatment of lumbar disc herniation patients, not one-sided that the symptoms of low back pain only from mechanical oppression.

Characterization, promoter analysis and expression of the interleukin-6 gene in blunt snout bream, Megalobrama amblycephala

Interleukin-6 (IL-6) is one of the most important multifunctional cytokines, playing essential roles in mediating the innate and adaptive immune responses. In this study, il-6 gene and its promoter from blunt snout bream, Megalobrama amblycephala, were characterized, and its expression at the transcript level in healthy fish and after bacterial infection was determined by quantitative real-time PCR. The results showed that the M. amblycephala il-6 (Mamil-6) cDNA had an ORF of 699 bp, encoding 232 amino acids, and contained 9 instable motifs in the 3' UTR. The deduced MamIL-6 possessed a 24-amino acid signal peptide and was located in the cytoplasm. Although sequence alignment and phylogenetic analysis revealed that IL-6 is poorly conserved in vertebrates, the protein and genomic structure of il-6 gene was well conserved. Analysis of the Mamil-6 promoter revealed the presence of a conserved TATA box and six major cis-regulatory elements, including C/EBPβ (NF-IL6), AP-1, CRE, GRE, GATA and NF-κB binding sites. In healthy fish, Mamil-6 was the most abundant in the spleen. After Aeromonas hydrophila infection, Mamil-6 was significantly up-regulated in all 6 immune-related tissues examined, suggesting that Mamil-6 plays an important role in the blunt snout bream immune system.

Whole-Body In Vivo Monitoring of Inflammatory Diseases Exploiting Human Interleukin 6-Luciferase Transgenic Mice

Chronic inflammation underlies the pathological progression of various diseases, and thus many efforts have been made to quantitatively evaluate the inflammatory status of the diseases. In this study, we generated a highly sensitive inflammation-monitoring mouse system using a bacterial artificial chromosome (BAC) clone containing extended flanking sequences of the human interleukin 6 gene (hIL6) locus, in which the luciferase (Luc) reporter gene is integrated (hIL6-BAC-Luc). We successfully monitored lipopolysaccharide-induced systemic inflammation in various tissues of the hIL6-BAC-Luc mice using an in vivo bioluminescence imaging system. When two chronic inflammatory disease models, i.e., a genetic model of atopic dermatitis and a model of experimental autoimmune encephalomyelitis (EAE), were applied to the hIL6-BAC-Luc mice, luciferase bioluminescence was specifically detected in the atopic skin lesion and central nervous system, respectively. Moreover, the Luc activities correlated well with the disease severity. Nrf2 is a master transcription factor that regulates antioxidative and detoxification enzyme genes. Upon EAE induction, the Nrf2-deficient mice crossed with the hIL6-BAC-Luc mice exhibited enhanced neurological symptoms concomitantly with robust luciferase luminescence in the neuronal tissue. Thus, whole-body in vivo monitoring using the hIL6-BAC-Luc transgenic system (WIM-6 system) provides a new and powerful diagnostic tool for real-time in vivo monitoring of inflammatory status in multiple different disease models.

The histone demethylase jumonji coordinates cellular senescence including secretion of neural stem cell-attracting cytokines

Jumonji domain-containing protein 3 (JMJD3/KDM6B) demethylates lysine 27 on histone H3 (H3K27me3), a repressive epigenetic mark controlling chromatin organization and cellular senescence. To better understand the functional consequences of JMJD3 its expression was investigated in brain tumor cells. Querying patient expression profile databases confirmed JMJD3 overexpression in high-grade glioma. Immunochemical staining of two glioma cell lines, U251 and U87, indicated intrinsic differences in JMJD3 expression levels that were reflected in changes in cell phenotype and variations associated with cellular senescence, including senescence-associated β-galactosidase (SA-β-gal) activity and the senescence-associated secretory phenotype (SASP). Overexpressing wild-type JMJD3 (JMJD3wt) activated SASP-associated genes, enhanced SA-β-gal activity, and induced nuclear blebbing. Conversely, overexpression of a catalytically inactive dominant negative mutant JMJD3 (JMJD3mut) increased proliferation. In addition, a large number of transcripts were identified by RNA-seq as altered in JMJD3 overexpressing cells, including cancer- and inflammation-related transcripts as defined by Ingenuity Pathway Analysis. These results suggest that expression of the SASP in the context of cancer undermines normal tissue homeostasis and contributes to tumorigenesis and tumor progression. These studies are therapeutically relevant because inflammatory cytokines have been linked to homing of neural stem cells and other stem cells to tumor loci.

IMPLICATIONS

This glioma study brings together actions of a normal epigenetic mechanism (JMJD3 activity) with dysfunctional activation of senescence-related processes, including secretion of SASP proinflammatory cytokines and stem cell tropism toward tumors.

The varying faces of IL-6: From cardiac protection to cardiac failure

IL6 is a pleiotropic cytokine that is made in response to perturbations in homeostasis. IL6 becomes elevated in the acute response to host injury and can activate immune cells, direct immune cell trafficking, signal protective responses in local tissue, initial the acute phase response or initiate wound healing. In the short term this proinflammatory response is protective and limits host damage. It is when this acute response remains chronically activated that IL6 becomes pathogenic to the host. Chronically elevated IL6 levels lead to chronic inflammation and fibrotic disorders. The heart is a tissue where this temporal regulation of IL6 is very apparent. Studies from myocardial infarction show how short-term IL6 signaling can protect and preserve the heart tissue in response to acute damage, where long term IL6 signaling or an over-production of IL6R protein plays a causal role in cardiovascular disease. Thus, IL6 can be both protective and pathogenic, depending on the kinetics of the host response.

Regulation of the Interleukin-6 gene expression during monocytic differentiation of HL-60 cells by chromatin remodeling and methylation

The pro-inflammatory cytokine Interleukin (IL)-6 is involved in the proliferation and differentiation of leukocytes and non-immune cells, but its overproduction is associated with inflammatory and autoimmune disorders. The main producers of IL-6 are mature monocytes, whereas progenitor cells and the promyeloid cell line HL-60 do not synthesize IL-6. In contrast, HL-60 cells differentiated into monocytic cells were able to express IL-6 after lipopolysaccharide (LPS) stimulation. This study investigated the chromatin structure of the IL-6 promoter and the effect of methylation on IL-6 gene regulation during monopoiesis. The results show that the proximal IL-6 promoter regions I to III (+13/-329) were inaccessible in undifferentiated HL-60 cells but became significantly accessible in differentiated HL-60 cells stimulated with LPS. Region IL-6 VI (-1099/-1142) remained closed, but the upstream region IL-6 VII (-2564/-2877) relaxed after differentiation and LPS treatment. The opening of IL-6 IV (-309/-521) and IL-6V (-500/-722), containing DNA and histone methylation sites, was differentiation-dependent only. Demethylation experiments using 5-aza-2'-deoxycytidine (AZA) followed by LPS stimulation revealed a significant enhanced IL-6 mRNA expression and protein release by HL-60 cells. AZA treatment resulted in significant increased IL-6 promoter accessibilities, identifying methylation as an important repressor of IL-6 gene regulation in promyeloid cells. The histone deacetylase (HDAC) inhibitor trichostatin A (TSA) had no effect on IL-6 promoter accessibility. Our data indicate that during monopoiesis the proximal IL-6 promoter is reorganized into an accessible conformation allowing transcription of IL-6 after LPS stimulation. DNA methylation appears to be the essential epigenetic mechanism in IL-6 gene expression of mature monocytes and their progenitors by controlling the chromatin structure.

The association of the 174G>C polymorphism of interleukin 6 gene with diabetic nephropathy in patients with type 2 diabetes mellitus

AIMS

To evaluate the association of 174G>C polymorphism on interleukin-6 (IL-6) gene with diabetic nephropathy in patients with type 2 diabetes.

METHODS

A total of 393 Greek subjects with type 2 diabetes (mean age 66.5±10.0years, men n=203, women n=190) were examined. Diabetic nephropathy was defined as presence of microalbuminuria and/or proteinuria. The IL-6 174G>C polymorphism was detected by polymerase chain reaction and appropriate restriction enzyme digestion. High sensitivity C-reactive protein was assayed by particle-enhanced immunonephelometry.

RESULTS

The genotype distribution (%) was GG: 49.1, GC: 26.8 and CC: 24.1, with no gender difference. The CC homozygotes had lower albumin excretion (mg/24h) in comparison with the GC genotype [CC: 8.9 (4.0-20.9) vs GC: 21.95 (9.1-53.35), P=0.004]. Participants with the GC genotype tended to have more frequently nephropathy than those with the GG or the CC genotype [GC: 44.55% vs GG: 35.1% and CC: 28.3%, P=0.07)]. The CC homozygotes in comparison with GC heterozygotes had lower odds to have nephropathy (odds ratio: 0.51, 95% confidence intervals=0.28-0.91, P=0.02), even after adjustment for sex, age, duration of diabetes, body mass index, smoking, hypertension, lipids and glycated hemoglobin, (P=0.01).

CONCLUSION

In type 2 diabetes states, CC homozygotes have lower albumin excretion and are protected from nephropathy in comparison with GC genotypes.

HNRNPA1 interacts with a 5'-flanking distal element of interleukin-6 and upregulates its basal transcription

Interleukin-6 (IL-6) is an important pro-inflammatory cytokine involved in many autoimmune and inflammatory diseases. We have shown previously that a region from −5307 to −5202 bp upstream of the IL-6 transcriptional start site is responsible for basal IL-6 gene expression and that there were DNA binding proteins involved from EMSA and transient expression experiments. Here we have combined surface plasmon resonance technology with mass spectrometry analysis and identified nuclear proteins bound to this region. HNRNPA1 and HNRNPA2B1 were found consistently. EMSA supershift and chromatin immunoprecipitation assays confirmed the involvement of HNRNPA1, but not HNRNPA2B1. Knocking down HNRNPA1 expression by siRNA resulted in reduced IL-6 transcriptional activity as assessed from transfection experiments using reporter constructs, mRNA and protein measurements. Overexpression of HNRNPA1 cDNA increased IL-6 mRNA expression. This regulation was dependent on the presence of the sequence from −5307 to −5202 bp of the IL-6 gene. Thus, HNRNPA1 is a novel transcriptional regulator of IL-6 expression, acting via the 5′ flanking sequence of the gene.

S100A8 and S100A9 induce cytokine expression and regulate the NLRP3 inflammasome via ROS-dependent activation of NF-κB(1.)

S100A8 and S100A9 are cytoplasmic proteins expressed by phagocytes. High concentrations of these proteins have been correlated with various inflammatory conditions, including autoimmune diseases such as rheumatoid arthritis and Crohn's disease, as well as autoinflammatory diseases. In the present study, we examined the effects of S100A8 and S100A9 on the secretion of cytokines and chemokines from PBMCs. S100A8 and S100A9 induced the secretion of cytokines such as IL-6, IL-8, and IL-1β. This secretion was associated with the activation and translocation of the transcription factor NF-κB. Inhibition studies using antisense RNA and the pharmacological agent BAY-117082 confirmed the involvement of NF-κB in IL-6, IL-8, and IL-1β secretion. S100A8- and S100A9-mediated activation of NF-κB, the NLR family, pyrin domain-containing 3 (NLRP3) protein, and pro-IL-1β expression was dependent on the generation of reactive oxygen species. This effect was synergistically enhanced by ATP, a known inflammasome activator. These results suggest that S100A8 and S100A9 enhance the inflammatory response by inducing cytokine secretion of PBMCs.

Differential DNA methylation regions in cytokine and transcription factor genomic loci associate with childhood physical aggression

Background

Animal and human studies suggest that inflammation is associated with behavioral disorders including aggression. We have recently shown that physical aggression of boys during childhood is strongly associated with reduced plasma levels of cytokines IL-1α, IL-4, IL-6, IL-8 and IL-10, later in early adulthood. This study tests the hypothesis that there is an association between differential DNA methylation regions in cytokine genes in T cells and monocytes DNA in adult subjects and a trajectory of physical aggression from childhood to adolescence.

Methodology/Principal Findings

We compared the methylation profiles of the entire genomic loci encompassing the IL-1α, IL-6, IL-4, IL-10 and IL-8 and three of their regulatory transcription factors (TF) NFkB1, NFAT5 and STAT6 genes in adult males on a chronic physical aggression trajectory (CPA) and males with the same background who followed a normal physical aggression trajectory (control group) from childhood to adolescence. We used the method of methylated DNA immunoprecipitation with comprehensive cytokine gene loci and TF loci microarray hybridization, statistical analysis and false discovery rate correction. We found differentially methylated regions to associate with CPA in both the cytokine loci as well as in their transcription factors loci analyzed. Some of these differentially methylated regions were located in known regulatory regions whereas others, to our knowledge, were previously unknown as regulatory areas. However, using the ENCODE database, we were able to identify key regulatory elements in many of these regions that indicate that they might be involved in the regulation of cytokine expression.

Conclusions

We provide here the first evidence for an association between differential DNA methylation in cytokines and their regulators in T cells and monocytes and male physical aggression.

IL-6 polymorphisms: a useful genetic tool for inflammation research?

In 1998, we described a novel polymorphism in the promoter (G>C, rs1800795) of the IL-6 (IL6) gene. The common allele, G, exhibited higher transcriptional activity in gene reporter assays and was associated with higher serum IL-6 levels in a small cohort of healthy subjects. We explored the ethnic distribution of these alleles and found significant differences among people of mixed European descent, Africans, and Gujarati Asians. Disease association was established in a cohort of 92 children of mixed European descent from the United Kingdom with systemic juvenile idiopathic arthritis (sJIA), with the GG genotype being significantly increased in sJIA cases compared with that in 383 controls, especially in those under 6 years old (P = 0.01). This polymorphism has since been used as a functional variant to explore the role of elevated IL-6 levels in many common disease states, confirming the key causal role of IL-6 in human health and disease.

Systems Biological Approaches Reveal Non-additive Responses and Multiple Crosstalk Mechanisms between TLR and GPCR Signaling

A variety of ligands differ in their capacity to bind the receptor, elicit gene expression, and modulate physiological responses. Such receptors include Toll-like receptors (TLRs), which recognize various patterns of pathogens and lead to primary innate immune activation against invaders, and G-protein coupled receptors (GPCRs), whose interaction with their cognate ligands activates heterotrimeric G proteins and regulates specific downstream effectors, including immuno-stimulating molecules. Once TLRs are activated, they lead to the expression of hundreds of genes together and bridge the arm of innate and adaptive immune responses. We characterized the gene expression profile of Toll-like receptor 4 (TLR4) in RAW 264.7 cells when it bound with its ligand, 2-keto-3-deoxyoctonate (KDO), the active part of lipopolysaccharide. In addition, to determine the network communications among the TLR, Janus kinase (JAK)/signal transducer and activator of transcription (STAT), and GPCR, we tested RAW 264.7 cells with KDO, interferon-β, or cAMP analog 8-Br. The ligands were also administered as a pair of double and triple combinations.

Effects of genetic variation on chromatin structure and the transcriptional machinery: analysis of the IL6 gene locus

The presence of functional regulatory polymorphism at the interleukin 6 (IL6) locus is uncertain, with many conflicting in vitro findings. To examine the in vivo effect of the three putative functional IL6 promoter variants, -174G>C, -572G>C and -6331T>C, two complementary techniques, allele-specific chromatin immunoprecipitation and allele-specific formaldehyde-assisted isolation of regulatory elements, were carried out using unrelated lymphoblast cell lines of known genotype. There were no allele-specific effects for all three single-nucleotide polymorphisms (SNPs) under basal conditions. Upon IL-1β stimulation, however, allele-specific effects were seen for the -6331 allele, which showed both increased RNA polymerase II loading (56%, P=0.001) and increased open chromatin (59%, P=0.004) for the T allele, which is in line with previous reports of this SNP and the effects from acute inflammation. These studies highlight the importance of examining chromatin under different environmental conditions when studying the functionality of regulatory polymorphisms.

Genetic susceptibility of intervertebral disc degeneration among young Finnish adults

BACKGROUND

Disc degeneration (DD) is a common condition that progresses with aging. Although the events leading to DD are not well understood, a significant genetic influence has been found. This study was undertaken to assess the association between relevant candidate gene polymorphisms and moderate DD in a well-defined and characterized cohort of young adults. Focusing on young age can be valuable in determining genetic predisposition to DD.

METHODS

We investigated the associations of existing candidate genes for DD among 538 young adults with a mean age of 19 belonging to the 1986 Northern Finland Birth Cohort. Nineteen single nucleotide polymorphisms (SNP) in 16 genes were genotyped. We evaluated lumbar DD using the modified Pfirrmann classification and a 1.5-T magnetic resonance scanner for imaging.

RESULTS

Of the 538 individuals studied, 46% had no degeneration, while 54% had DD and 51% of these had moderate DD. The risk of DD was significantly higher in subjects with an allele G of IL6 SNPs rs1800795 (OR 1.45, 95% CI 1.07-1.96) and rs1800797 (OR 1.37, 95% CI 1.02-1.85) in the additive inheritance model. The role of IL6 was further supported by the haplotype analysis, which resulted in an association between the GGG haplotype (SNPs rs1800797, rs1800796 and rs1800795) and DD with an OR of 1.51 (95% CI 1.11-2.04). In addition, we observed an association between DD and two other polymorphisms, SKT rs16924573 (OR 0.27 95% CI 0.07-0.96) and CILP rs2073711 in women (OR 2.04, 95% CI 1.07-3.89).

CONCLUSION

Our results indicate that IL6, SKT and CILP are involved in the etiology of DD among young adults.

The dysregulation of the monocyte/macrophage effector function induced by isopropanol is mediated by the defective activation of distinct members of the AP-1 family of transcription factors

Isopropanol is the second most common cause of short-chain alcohol acute intoxication. Nonethanolic short-chain alcohols mediate their immunomodulatory effect by interfering with nuclear factor of activated T cells (NFAT) activation with or without additional activator protein-1 (AP-1) involvement. In the present study, we examined the immunomodulation induced by isopropanol in conditions that are not reliant on NFAT: the inflammatory cytokine response of lipopolysaccharide (LPS)-stimulated monocytes. Our hypothesis was that isopropanol acute exposure would have an attenuated effect or no consequence in this setting. To our surprise, the impairment of AP-1 activation was sufficient to mediate a severe and dose-dependent phenotype in human monocytes in vitro at alcohol concentrations as low as 0.16% (or 26 mM). There were three outcomes: interleukin (IL)-1β/IL-8 were unaltered; IL-6 was upregulated; and tumor necrosis factor alpha (TNF-α)/CCL2 were downregulated. The effector function of human monocyte-derived macrophages was also compromised. Our results showed that Toll-like receptor 4 early signaling was preserved, as isopropanol did not change the kinase activity of the IL-1 receptor-associated kinase 1 in LPS-stimulated cells. The nuclear factor-κB signaling cascade and the p38/c-Jun N-terminal kinase modules of the mitogen-activated protein kinase pathway were alcohol insensitive. Conversely, the activation of extracellular signal-regulated protein kinase and, ultimately, of c-Fos and JunB were impaired. The alcohol-induced cytokine dysregulation was confirmed in a mouse model of isopropanol intoxication in which the production of TNF-α in response to LPS challenge was virtually abolished. The magnitude of this alcohol effect was sufficiently high to rescue animals from LPS-induced toxic shock. Our data contribute to the dismal body of information on the immunotoxicology of isopropanol, one of the most ubiquitous chemicals to which the general population is significantly exposed.

Visfatin through STAT3 activation enhances IL-6 expression that promotes endothelial angiogenesis

Signal transducer and activator of transcription 3 (STAT3) acts as a mediator and biomarker in endothelial activation. We have recently shown that a novel adipokine visfatin promotes endothelial angiogenesis. The present study was to determine whether visfatin affects STAT3 activity and to explore the potential target gene(s). Here, we found that visfatin induced the activation of STAT3, as characterized by increased tyrosine phosphorylation, nuclear translocation, and DNA-binding activity in human endothelial cells. In addition, visfatin significantly upregulated mRNA and protein levels of endothelial interleukin-6 (IL-6), which was blocked by a specific inhibitor of STAT3 signaling and by the transfection of siRNA specific for STAT3. Furthermore, visfatin-induced angiogenesis was reduced by the inhibition of STAT3 signaling or neutralization of IL-6 function, as measured by tube formation, rat aortic ring assay, and mouse Matrigel plug assay. Taken together, our results provide the first example of STAT3-dependent endothelial IL-6 induction by visfatin and of the role of IL-6 in mediating visfatin-induced angiogenesis.

Associations of IL6 polymorphisms with lung function decline and COPD

BACKGROUND

Interleukin-6 (IL6) is a pleiotropic pro-inflammatory and immunomodulatory cytokine which probably plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). There is a functional single nucleotide polymorphism (SNP), -174G/C, in the promoter region of IL6. It was hypothesised that IL6 SNPs influence susceptibility for impaired lung function and COPD in smokers.

METHODS

Seven and five SNPs in IL6 were genotyped in two nested case-control samples derived from the Lung Health Study (LHS) based on phenotypes of rate of decline of forced expiratory volume in 1 s (FEV(1)) over 5 years and baseline FEV(1) at the beginning of the LHS. Serum IL6 concentrations were measured for all subjects. A partially overlapping panel of nine IL6 SNPs was genotyped in 389 cases of COPD from the National Emphysema Treatment Trial (NETT) and 420 controls from the Normative Aging Study (NAS).

RESULTS

In the LHS, three IL6 SNPs were associated with decline in FEV(1) (0.023< or =p< or =0.041 in additive models). Among them, the IL6_-174C allele was associated with a rapid decline in lung function. The association was more significant in a genotype-based analysis (p = 0.006). In the NETT-NAS study, IL6_-174G/C and four other IL6 SNPs, all of which are in linkage disequilibrium with IL6_-174G/C, were associated with susceptibility to COPD (0.01< or =p< or =0.04 in additive genetic models).

CONCLUSION

The results suggest that the IL6_-174G/C SNP is associated with a rapid decline in FEV(1) and susceptibility to COPD in smokers.

Polymorphisms cyclooxygenase-2 -765G>C and interleukin-6 -174G>C are associated with serum inflammation markers in a high cardiovascular risk population and do not modify the response to a Mediterranean diet supplemented with virgin olive oil or nuts

Inflammation is involved in cardiovascular diseases. Some studies have found that the Mediterranean diet (MD) can reduce serum concentrations of inflammation markers. However, none of these studies have analyzed the influence of genetic variability in such a response. Our objective was to study the effect of the -765G>C polymorphism in the cyclooxygenase-2 (COX-2) gene and the -174G>C polymorphism in the interleukin-6 (IL-6) gene on serum concentrations of IL-6, C-reactive protein, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule-1 as well as their influence on the response to a nutritional intervention with MD. An intervention study in a high cardiovascular risk Mediterranean population (314 men and 407 women) was undertaken. Participants were randomly assigned to consume a low-fat control diet or a MD supplemented with virgin olive oil or nuts. Measures were obtained at baseline and after a 3-mo intervention period. At baseline, the COX-2 -765G>C polymorphism was associated with lower serum IL-6 (5.85 +/- 4.82 in GG vs. 4.74 +/- 4.14 ng/L in C-allele carriers; P = 0.002) and ICAM-1 (265.8 +/- 114.8 in GG vs. 243.0 +/- 107.1 microg/L in C-carriers; P = 0.018) concentrations. These differences remained significant after multivariate adjustment. The IL-6 -174G>C polymorphism was associated with higher (CC vs. G-carriers) serum ICAM-1 concentrations in both men and women and with higher serum IL-6 concentrations in men. Following the dietary intervention, no significant gene x diet interactions were found. In conclusion, although COX-2 -765G>C and IL-6 -174G>C polymorphisms were associated with inflammation, consuming a MD (either supplemented with virgin olive oil or nuts) reduced the concentration of inflammation markers regardless of these polymorphisms.

Cytokine and cytokine receptor gene polymorphisms and their functionality

Cytokines, signaling proteins produced by a variety of cell types, are essential for the development and functioning of both innate and adaptive immune response. Cytokine gene expression is tightly regulated, and aberrant expression from environmental and genetic polymorphism has been implicated in a range of diseases, susceptibility to infections, and responses to treatment. This review concentrates on the functionality of cytokine and cytokine receptor gene polymorphisms; it is through these variants that genuine disease-associations are based. Several mechanisms for single nucleotide polymorphism (SNP) functionality are present within cytokine genes including: amino acid changes (IL-6R, IL-13, IL-1alpha), exon skipping (IL-7Ralpha), proximal promoter variants (IL-1beta, IL-Ra, IL-2, IL-6, IL-10, IL-12, IL-13, IL-16, TNF, IFN-gamma, TGF-beta), distal promoter variants (IL-6, IL-18) and intronic enhancer variants (IL-8).

Characterization of DNA-binding proteins using multiplexed competitor EMSA

We describe a low-cost high-throughput technique to characterize nuclear protein DNA-binding interactions. This technique, known as Multiplexed Competitor Electrophoretic Mobility Shift Assay, uses a series of multiplexed oligonucleotide DNA consensus competitors, in combination with a standard electrophoretic mobility shift assay procedure, to efficiently characterize DNA-binding proteins. We show utility for the method to identify a previously unreported hepatocyte nuclear factor-3 site created in intron 8 of the lipoprotein lipase gene by a common single-nucleotide polymorphism (rs327).