Prevalence, distribution and functional significance of the -237C to T polymorphism in the IL-12Rβ2 promoter in Indian tuberculosis patients

Epidemiology of metabolic syndrome in Tunisia. HSHS 5 study

OBJECTIVE

To measure the prevalence of metabolic syndrome and its components in the HSHS cohort (Hammam Sousse, Tunisia), in 2009, and to identify its determining factors.

METHODS

This was a descriptive epidemiological study of the "community based" type having focused on a random sample of people aged 20 and over. The metabolic syndrome was defined according to the criteria of the "International Diabetes Federation" (IDF 2005) and those of the "National Cholesterol Education Program-Adult Treatment Panel III" (NCEP-ATP III, 2001).

RESULTS

The study involved 1441 people including 960 women (66.6%). The age- and sex-adjusted prevalences of increased waist circumference, blood pressure, blood sugar and triglycerides, and decreased HDL-cholesterol were respectively 63.2%, 95%CI[62.5-63.8]; 47.7%, 95%CI[47.4-48.6]; 25.7%, 95%CI[25.1-26.2]; 11.9%, 95%CI[11.4-12.3] and 65,6%, 95%CI[65.0-66.2], according to IDF thresholds and 37.4%, 95%CI[36.3-37.6]; 45.7%, 95%CI[45.4-46.6]; 13.8%, 95%CI[13.4-14.2]; 8.4%, 95%CI[8.0-8.7] and 61.9%, 95%CI[61.2-62.5], according to those of the NCEP-ATP III. The prevalence of metabolic syndrome adjusted for age and sex was 36.5% 95%CI[33.0%-38.9%] according to the IDF definition and 23.0% 95%CI[20.4%-25.6%] according to that of NCEP-ATP III. The multivariate study by logistic regression made it possible to retain three significant independent determining factors of the metabolic syndrome: age ≥40 years, low level of physical activity and family history of diabetes mellitus with respectively adjusted ORs of 3.77 95%CI[2.70-5.27], 1.39 95%CI[1.01-1.89], 1.62 95%CI[1.21-2.15], according to IDF and 5.87 95%CI[3.88 -8.88], 1.47 95%CI[1.07-2.01] and 1.45 95%CI[1.07-1.96], according to NCEP-ATP III .

CONCLUSION

With this high prevalence rate of the metabolic syndrome, the establishment of an action plan would be essential. This plan should be based on the combination of the promotion of physical activity and screening for the components of the metabolic syndrome, particularly in subjects aged 40 or over, with a family history of diabetes mellitus.

Impact and prognosis of the expression of IFN-α among tuberculosis patients

Mycobacterium tuberculosis (M.tb) infection stimulates the release of cytokines, including interferons (IFNs). IFNs are initiators, regulators, and effectors of innate and adaptive immunity. Accordingly, the expression levels of Type I (α, β) and II (γ) IFNs, among untreated tuberculosis (TB) patients and household contacts (HHC) clinically free of TB was assessed. A total of 264 individuals (TB patients-123; HHC-86; laboratory volunteers-55; Treated TB patients-36) were enrolled for this study. IFN-α mRNA expression levels predominated compared to IFN-γ and IFN-β among untreated TB patients. IFN-α transcripts were ~3.5 folds higher in TB patients compared to HHC, (p<0.0001). High expression of IFN-α was seen among 46% (56/ 123) of the TB patients and 26%, (22/86) of HHCs. The expression levels of IFN-α correlated with that of IFN transcriptional release factor 7 (IRF) (p<0.0001). In contrast, an inverse relationship exists between PGE2 and IFN-α expression levels; high IFN-α expressers were associated with low levels of PGE2 and vice-versa (Spearman’s rho = -0.563; p<0.0001). In-vitro, IFN-α failed to restrict the replication of intracellular M.tb. The anti-mycobacterial activity of IFN-γ was compromised in the presence of IFN-α, but not by IFN-β. The expression of IFN-α and β diminished or is absent, among successfully treated TB patients. These observations suggest the utility of assessment of Type I IFNs expression levels as a prognostic marker to monitor tuberculosis patient response to chemotherapy because changes in Type I IFNs expression are expected to precede the clearance and /reduction in bacterial load.

Lipopolysaccharide downregulates macrophage-derived IL-22 to modulate alcohol-induced hepatocyte cell death

Interleukin-22 (IL-22) is a Th17 cell hepatoprotective cytokine that is undergoing clinical trials to treat patients with alcoholic hepatitis (AH). Lipopolysaccharide (LPS) activation of macrophage is implicated in hepatocyte cell death and pathogenesis of AH. The role of IL-22 production from macrophage, its regulation by LPS, and effects on alcohol-induced hepatocyte cell death are unexplored and were examined in this study. Low levels of IL-22 mRNA/protein were detected in macrophage but were significantly upregulated by 6.5-fold in response to the tissue reparative cytokine IL-10. Conversely, LPS significantly decreased IL-22 mRNA levels in a temporal and concentration-dependent manner with a maximum reduction of 5-fold. LPS downregulation of IL-22 mRNA levels was rescued in the presence of a pharmacological inhibitor of c-Jun NH2-terminal kinase (JNK) and by JNK knockdown. Next, we explored whether macrophage-derived IL-22 regulated ethanol-induced hepatocyte death. Conditioned media from IL-10-stimulated macrophages attenuated ethanol-induced hepatocyte caspase-3/7 activity, and apoptosis as assessed by fluorometric assay and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. This effect was diminished in conditioned media from macrophages with IL-22 knockdown. Cytokine analysis in sera samples of patients with AH revealed that IL-22 levels were significantly elevated compared with healthy controls and heavy-drinking controls, implying a state of IL-22 resistance in human AH. Macrophage-derived IL-22 protects hepatocytes from ethanol-induced cell death. IL-22 downregulation is a new regulatory target of LPS in the pathogenesis of AH.

Alcohol stimulates macrophage activation through caspase-dependent hepatocyte derived release of CD40L containing extracellular vesicles

BACKGROUND & AIMS

The mechanisms by which hepatocyte exposure to alcohol activates inflammatory cells such as macrophages in alcoholic liver disease (ALD) are unclear. The role of released nano-sized membrane vesicles, termed extracellular vesicles (EV), in cell-to-cell communication has become increasingly recognized. We tested the hypothesis that hepatocytes exposed to alcohol may increase EV release to elicit macrophage activation.

METHODS

Primary hepatocytes or HepG2 hepatocyte cell lines overexpressing ethanol-metabolizing enzymes alcohol dehydrogenase (HepG2(ADH)) or cytochrome P450 2E1 (HepG2(Cyp2E1)) were treated with ethanol and EV release was quantified with nanoparticle tracking analysis. EV mediated macrophage activation was monitored by analysing inflammatory cytokines and macrophage associated mRNA expression, immunohistochemistry, biochemical serum alanine aminotransferase and triglycerides analysis in our in vitro macrophage activation and in vivo murine ethanol feeding studies.

RESULTS

Ethanol significantly increased EV release by 3.3-fold from HepG2(Cyp2E1) cells and was associated with activation of caspase-3. Blockade of caspase activation with pharmacological or genetic approaches abrogated alcohol-induced EV release. EV stimulated macrophage activation and inflammatory cytokine induction. An unbiased microarray-based approach and antibody neutralization experiments demonstrated a critical role of CD40 ligand (CD40L) in EV mediated macrophage activation. In vivo, wild-type mice receiving a pan-caspase, Rho kinase inhibitor or with genetic deletion of CD40 (CD40(-/-)) or the caspase-activating TRAIL receptor (TR(-/-)), were protected from alcohol-induced injury and associated macrophage infiltration. Moreover, serum from patients with alcoholic hepatitis showed increased levels of CD40L enriched EV.

CONCLUSION

In conclusion, hepatocytes release CD40L containing EV in a caspase-dependent manner in response to alcohol exposure which promotes macrophage activation, contributing to inflammation in ALD.

Functional analysis of differences in transcriptional activity conferred by genetic variants in the 5' flanking region of the IL12RB2 gene

Interleukin 12 receptor β chain (IL12RB2) is a crucial regulatory factor involved in cell-mediated immune responses, and genetic variants of the gene encoding IL12RB2 are associated with susceptibility to various immune-related diseases. We previously demonstrated that haplotypes with single nucleotide polymorphisms (SNPs) in the 5' flanking region of IL12RB2, including -1035A>G (rs3762315) and -1023A>G (rs3762316), affect the expression of IL12RB2, thereby altering susceptibility to leprosy and periodontal diseases. In the present study, we identified transcription factors associated with the haplotype-specific transcriptional activity of IL12RB2 in T cells and NK cells. The -1023G polymorphism was found to create a consensus binding site for the transcription factor activating protein (AP)-1, and enzyme-linked immunosorbent assay (ELISA)-based binding assays showed that these SNPs enhanced AP-1 binding to this region. In reporter assays, suppression of JunB expression using siRNA eliminated differences in the -1035G/-1023G and -1035A/-1023A regions containing IL12RB2 promoter activity in Jurkat T cells and NK3.3 cells. These results suggested that the -1035/-1023 polymorphisms created differential binding affinities for JunB that could lead to differential IL12RB2 expression. Moreover, the -1035G and -1035A alleles formed binding sites for GATA-3 and myocyte enhancer factor-2 (MEF-2), respectively. Our data indicated that in addition to JunB, the SNP at -1035/-1023 influenced GATA-3 and MEF-2 binding affinity, potentially altering IL12RB2 transcriptional activity. These findings confirm the effects of rs3762315 and rs3762316 on IL12RB2 transcription. These genetic variants may alter cellular activation of T cells and NK cells and modify cell-mediated immune responses.

The NFKB1 polymorphism (rs4648068) is associated with the cell proliferation and motility in gastric cancer

BACKGROUND

We have demonstrated previously that NFKB1 single nucleotide polymorphism (SNP) rs4648068 GG homozygote was associated with the increased risk of gastric cancer in Chinese Han population. In this study, we constructed the recombinant plasmid pGL3-AA, pGL3-GG, pGL3-AA-NFKB and pGL3-GG-NFKB to investigate the function of rs4648068 by cell biology experiments.

METHODS

Quantitative real-time PCR was used to detect NFKB1 SNP rs4648068 genotype in the patients with gastric cancer. Anti-NF-κB1 p50 polyclonal antibodies were used for immunohistochemical analysis of the tissue specimens. The subsection of NFKB1 containing the promoter site and adjacent three consecutive exons were obtained by PCR technique and subcloned into the vector pGL3-Basic. Dual-Luciferase reporter assay was used to detect the transcriptional activity of the constructed promoter. Effects of transcription factor NFKB1 on C/EBPβ expression were determined by chromatin immunoprecipitation and Western analysis. Furthermore, proliferation and invasion ability of the transduced cell were also measured and compared.

RESULTS

Intensive staining for p50 expression was observed in the tissues of GG genotype patients, compared with those of GA group and AA genotype patients. The transcriptional activity of rs4648068 (A > G) by dual-Luciferase reporter assay suggested that the luciferase activity of homozygote group (pGL3-GG) was greater than that of the control (pGL3-AA), especially at the stimulation of LPS. We found that the luciferase activity was also influenced by pGL3-GG levels. The effects of NFKB1 rs4648068 were enhanced by rs4648065 on the transduced cells. The interaction between NFKB1 promoter nucleotide sequence and C/EBPβ was regulated by the functional SNP rs4648068 in SGC-7901 cells. Our data indicated that the transduction of pGL3 expression plasmid pGL3-GG-NFKB improved the proliferation and motility of gastric cancer cells. Correspondingly, the homozygote GG of SNP rs4648068 strengthened the transcriptional activity of NFKB1 and influenced the cell biological activity.

CONCLUSION

The transcriptional activity of NFKB1 was associated with SNP rs4648068, and this functional SNP site has the important effects on cell proliferation and motility.

Association between the IL17RA rs4819554 polymorphism and reduced renal filtration rate in the Spanish RENASTUR cohort

DNA variants at the genes that encode components of the IL17-pathway may contribute to the risk of impaired renal function/chronic kidney disease. Our aim was to determine whether common IL17RA single nucleotide polymorphisms (SNPs) were associated with a reduced estimated glomerular filtration rate (eGFR) in a cohort of healthy elderly individuals (n=650). We found a significantly higher frequency of SNP rs4819554 AA homozygotes among individuals with eGFR<60 ml/min/1.73 m(2) (n=90) (p=0.005, OR=2.11; 1.26-3.54), an effect that was independent of the presence of type 2 diabetes. Allele rs4819554 A had been associated to the risk of developing end stage renal disease, and was also linked to an increased expression of the IL17RA protein and higher levels of Th17 cell subsets. A scenario in which the pro-inflammatory role of the IL17-pathway contributes to kidney damage might explain the association between Il17RA polymorphisms and an impaired renal function.