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The rs361525 polymorphism does not increase production of tumor necrosis factor alpha by monocytes from alpha-1 antitrypsin deficient subjects with chronic obstructive pulmonary disease - a pilot study.

ABSTRACT: Polymorphisms in the TNF-A gene have been associated with chronic obstructive pulmonary disease (COPD) in some case-control studies. Previous work has shown that COPD/chronic bronchitis subjects with alpha-1 antitrypsin deficiency with the rs361525 TNF-? single nucleotide polymorphism have 100 times more TNF-in spontaneous sputum than disease matched controls. Our objective was to determine if the presence of this polymorphism increased TNF-? production by blood monocytes from COPD subjects.Monocytes from 18 COPD/alpha-1 antitrypsin deficient subjects, with and without the rs361525 polymorphism, were cultured in the presence or absence of lipopolysaccharide. Cell-free supernatants were analyzed by ELISA and real-time PCR performed using cDNA from extracted RNA. Baseline expression of TNF-? messenger RNA was no different between the groups. No difference in messenger RNA or secreted protein was observed over time in un-stimulated cells. TNF-? messenger RNA expression and protein was not higher in lipopolysaccharide-stimulated monocytes from subjects with the polymorphism compared to cells from patients with the wild-type allele.This small pilot study did not provide an explanation for the findings of earlier observations of the association of the rs361525 polymorphism with TNF-? in airways secretions. Possible reasons for the lack of concordance include the study of blood rather than tissue cells, the use of a single stimulant rather than biological secretions and the need for far greater subject numbers to overcome intra-subject variation in monocyte TNF-? production.

SUBMITTER: Gane JM

PROVIDER: S-EPMC4665865 | biostudies-other | 2015 Dec

REPOSITORIES: biostudies-other

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The rs361525 polymorphism does not increase production of tumor necrosis factor alpha by monocytes from alpha-1 antitrypsin deficient subjects with chronic obstructive pulmonary disease - a pilot study.

Gane Jennie M JM Stockley Robert A RA Sapey Elizabeth E

Journal of negative results in biomedicine 20151201

<h4>Background</h4>Polymorphisms in the TNF-A gene have been associated with chronic obstructive pulmonary disease (COPD) in some case-control studies. Previous work has shown that COPD/chronic bronchitis subjects with alpha-1 antitrypsin deficiency with the rs361525 TNF-α single nucleotide polymorphism have 100 times more TNF-in spontaneous sputum than disease matched controls. Our objective was to determine if the presence of this polymorphism increased TNF-α production by blood monocytes from ...[more]

PMID: 26620975

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Project description:Alpha 1 antitrypsin deficiency (AATD) is an autosomal co-dominant disorder characterized by a low level of circulating AAT, which significantly reduces protection for the lower airways against proteolytic burden caused by neutrophils. Neutrophils, which are terminally differentiated innate immune cells and play a critical role to clear pathogens, accumulate excessively in the lung of AATD individuals. The neutrophil burden in AATD individuals increases the risk for early-onset destructive lung diseases by producing neutrophil products such as reactive oxygen radicals and various proteases. The level of AAT in AATD individuals is not sufficient to inhibit the activity of neutrophil chemotactic factors such as CXCL-8 and LTB4, which could lead to alveolar neutrophil accumulation in AATD individuals. However, as neutrophils have a short lifespan, and apoptotic neutrophils are rapidly cleared by alveolar macrophages that outnumber the apoptotic neutrophils in the pulmonary alveolus, the increased chemotaxis activity does not fully explain the persistent neutrophil accumulation and the resulting chronic inflammation in AATD individuals. Here, we propose that the ability of alveolar macrophages to clear apoptotic neutrophils is impaired in AATD individuals and it could be the main driver to cause neutrophil accumulation in their lung. This study demonstrates that Z-AAT variant significantly increases the expression of pro-inflammatory cytokines including CXCL-8, CXCL1, LTB4, and TNFα in LPS-treated macrophages. These cytokines play a central role in neutrophil recruitment to the lung and in clearance of apoptotic neutrophils by macrophages. Our result shows that LPS treatment significantly reduces the efferocytosis ability of macrophages with the Z-AAT allele by inducing TNFα expression. We incubated monocyte-derived macrophages (MDMs) with apoptotic neutrophils and found that after 3 h of co-incubation, the expression level of CXCL-8 is reduced in M-MDMs but increased in Z-MDMs. This result shows that the expression of inflammatory cytokines could be increased by impaired efferocytosis. It indicates that the efferocytosis ability of macrophages plays an important role in regulating cytokine expression and resolving inflammation. Findings from this study would help us better understand the multifaceted effect of AAT on regulating neutrophil balance in the lung and the underlying mechanisms.

Project description:BackgroundPrevious studies conducted in various geographical and ethnical populations have shown that Alpha-1-antitrypsin (Alpha-1-AT) expression affects the occurrence and progression of chronic obstructive pulmonary disease (COPD). We aimed to explore the associations of rs9944155AG, rs1051052AG, and rs1243166AG polymorphisms in the Alpha-1-AT gene with the risk of COPD in Uygur population in the Kashgar region.MethodsFrom March 2013 to December 2015, a total of 225 Uygur COPD patients and 198 healthy people were recruited as cases and controls, respectively, in Kashgar region. DNA was extracted according to the protocol of the DNA genome kit, and Sequenom MassARRAY single-nucleotide polymorphism technology was used for genotype determination. Serum concentration of Alpha-1-AT was detected by enzyme-linked immunosorbent assay. A logistic regression model was used to estimate the associations of polymorphisms with COPD.ResultsThe rs1243166-G allele was associated with a higher risk of COPD (odds ratio [OR] = 2.039, 95% confidence interval [CI]: 1.116-3.725, P = 0.019). In cases, Alpha-1-AT levels were the highest among participants carrying rs1243166 AG genotype, followed by AA and GG genotype (χ2 = 11.89, P = 0.003). Similarly, the rs1051052-G allele was associated with a higher risk of COPD (OR = 19.433, 95% CI: 8.783-43.00, P < 0.001). The highest Alpha-1-AT levels were observed in cases carrying rs1051052 AA genotype, followed by cases with AG and GG genotypes (χ2 = 122.45, P < 0.001). However, individuals with rs9944155-G allele exhibited a lower risk of COPD than those carrying the rs9944155-A allele (OR = 0.121, 95% CI: 0.070-0.209, P < 0.001). In both cases and controls, no significant difference in Alpha-1-AT levels was observed among various rs9944115 genotypes.Conclusionsrs1243166, rs9944155, and rs1051052 sites of Alpha-1-AT may be associated with the COPD morbidity in Uygur population. While rs1243166-G allele and rs1051052-G allele are associated with an increased risk of developing COPD, rs9944155-G allele is a protect locus in Uygur population. Alpha-1-AT levels in Uygur COPD patients were lower than those in healthy people and differed among patients with different rs1051052 AG and rs1243166 AG genotypes.

Dataset Information

The rs361525 polymorphism does not increase production of tumor necrosis factor alpha by monocytes from alpha-1 antitrypsin deficient subjects with chronic obstructive pulmonary disease - a pilot study.

Publications

The rs361525 polymorphism does not increase production of tumor necrosis factor alpha by monocytes from alpha-1 antitrypsin deficient subjects with chronic obstructive pulmonary disease - a pilot study.

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