Genetic Association and Expression Studies Indicate a Role of Toll-Like Receptor 8 in Pulmonary Tuberculosis

Despite high rates of exposure, only 5–10% of people infected with Mycobacterium tuberculosis will develop active tuberculosis (TB) disease, suggesting a significant role for genetic variation in the human immune response to this infection. Here, we studied TB association and expression of 18 genes involved in the Toll-like receptor (TLR) pathways. Initially, we genotyped 149 sequence polymorphisms in 375 pulmonary TB patients and 387 controls from Indonesia. We found that four polymorphisms in the TLR8 gene on chromosome X showed evidence of association with TB susceptibility in males, including a non-synonymous polymorphism rs3764880 (Met1Val; P = 0.007, odds ratio (OR) = 1.8, 95% c.i. = 1.2–2.7). We genotyped these four TLR8 polymorphisms in an independent collection of 1,837 pulmonary TB patients and 1,779 controls from Russia and again found evidence of association in males (for rs3764880 P = 0.03, OR = 1.2, 95% c.i. = 1.02–1.48). Combined evidence for association is P = 1.2×10−3–6×10−4. In addition, a quantitative PCR analysis indicated that TLR8 transcript levels are significantly up-regulated in patients during the acute phase of disease (P = 9.36×10−5), relative to baseline levels following successful chemotherapy. A marked increase in TLR8 protein expression was also observed directly in differentiated macrophages upon infection with M. bovis bacille Calmette-Guérin (BCG). Taken together, our results provide evidence, for the first time, of a role for the TLR8 gene in susceptibility to pulmonary TB across different populations

An investigation of human serum amyloid A protein interaction with microorganisms

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Serum amyloid A is an innate immune opsonin for Gram-negative bacteria.

Serum amyloid A (SAA) is the major acute-phase protein in man and most mammals. Recently we demonstrated that SAA binds to many Gram-negative bacteria including Escherichia coli and Pseudomonas aeruginosa through outer membrane protein A (OmpA) family members. Therefore we investigated whether SAA altered the response of innate phagocytic cells to bacteria. Both the percentage of neutrophils containing E coli and the number of bacteria per neutrophil were greatly increased by SAA opsonization, equivalent to the increase seen for serum opsonization. In contrast, no change was seen for Streptococcus pneumoniae, a bacteria that did not bind SAA. Neutrophil reactive oxygen intermediate production in response to bacteria was also increased by opsonization with SAA. SAA opsonization also increased phagocytosis of E coli by peripheral blood mononuclear cell-derived macrophages. These macrophages showed strong enhancement of TNF-alpha and IL-10 production in response to SAA-opsonized E coli and P aeruginosa. SAA did not enhance responses in the presence of bacteria to which it did not bind. These effects of SAA occur at normal concentrations consistent with SAA binding properties and a role in innate recognition. SAA therefore represents a novel innate recognition protein for Gram-negative bacteria

Genetic association and expression studies indicate a role of toll-like receptor 8 in pulmonary tuberculosis.

Despite high rates of exposure, only 5-10% of people infected with Mycobacterium tuberculosis will develop active tuberculosis (TB) disease, suggesting a significant role for genetic variation in the human immune response to this infection. Here, we studied TB association and expression of 18 genes involved in the Toll-like receptor (TLR) pathways. Initially, we genotyped 149 sequence polymorphisms in 375 pulmonary TB patients and 387 controls from Indonesia. We found that four polymorphisms in the TLR8 gene on chromosome X showed evidence of association with TB susceptibility in males, including a non-synonymous polymorphism rs3764880 (Met1Val; P = 0.007, odds ratio (OR) = 1.8, 95% c.i. = 1.2-2.7). We genotyped these four TLR8 polymorphisms in an independent collection of 1,837 pulmonary TB patients and 1,779 controls from Russia and again found evidence of association in males (for rs3764880 P = 0.03, OR = 1.2, 95% c.i. = 1.02-1.48). Combined evidence for association is P = 1.2x10(-3)-6x10(-4). In addition, a quantitative PCR analysis indicated that TLR8 transcript levels are significantly up-regulated in patients during the acute phase of disease (P = 9.36x10(-5)), relative to baseline levels following successful chemotherapy. A marked increase in TLR8 protein expression was also observed directly in differentiated macrophages upon infection with M. bovis bacille Calmette-Guérin (BCG). Taken together, our results provide evidence, for the first time, of a role for the TLR8 gene in susceptibility to pulmonary TB across different populations

Polen

Polen : Land in der Mitte Europas : Exkursionsbericht / [Hrsg.: Rudolf Schönbach ...] - Augsburg, 1977. - 115 S

Cluster analysis using self-organizing map with further Panther analysis.

<p>Genespring GX10 was used to analyse transcripts which were significantly different between the four conditions (Active disease, Treatment, Recovered and Controls) using one-way ANOVA and subsequently subjected to self-organizing map clustering analysis. Upregulated transcripts (left panel) and downregulated transcripts (right panel) were subjected to further analysis through Panther.</p

The distinct pathways in which gene ontology clusters 56 of the genes with increased expression normalizing during treatment.

<p>Significant Panther biological processes was detected for 56 up-regulated genes, type 1 interferon expression is increased in this group.</p

Validating microarray data by qRT-PCR.

<p>Microarray results were validated by qRT-PCR. 17 genes from the 26 genes were found to be significantly different between TB patients with active disease and healthy controls, 15 genes from the 26 genes were found to be significantly different between live BCG-infected THP-1 cells at 20 hours compared to uninfected controls, and 5 genes from 26 genes were found to be significantly different between mice infected with active TB and mock infected mice, using student’s T test (P<0.05). Three genes which were common to all 3 models show similar levels of expression with both techniques applied. The fold increase for microarray technique (blue, orange and yellow) and qRT-PCR technique (light blue, light orange and light yellow) for patients, THP-1 cells and mice respectively. Microarray data (and their corresponding qRT-PCR data) that were not validated by qRT-PCR are not shown.</p

Comparison of differential gene expression between <i>M.tb</i> infected patients and BCG infected THP-1 cells.

<p>Venn diagram representing the 875 significantly differentially expressed in TB patients and 461 transcripts significantly differentially expressed in THP-1 BCG <i>in vitro</i> model. A total of 95 transcripts were found to be in common between these two systems. Red – transcripts for active TB patients only; Green – Common between TB patients and BCG-infected THP-1 cell line; Blue – transcripts for BCG-infected THP-1 only.</p