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Association of TLR4-T399I polymorphism with chronic obstructive pulmonary disease in smokers.

Speletas M, Merentiti V, Kostikas K, Liadaki K, Minas M, Gourgoulianis K, Germenis AE - Clin. Dev. Immunol. (2010)

Bottom Line: Recent studies have indicated that the impairment of TLR signaling might play a crucial role in the development of emphysema.For this purpose we investigated the prevalence and any possible associations of common TLR polymorphisms (TLR2-R753Q, TLR4-D299G, and TLR4-T399I) in a group of 240 heavy smokers (>20 pack years), without overt atherosclerosis disease, of whom 136 had developed COPD and 104 had not.Considering that infections contribute to COPD and emphysema pathogenesis, our findings possibly indicate that dysfunctional polymorphisms of innate immune genes can affect the development of COPD in smokers.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Histocompatibility, University of Thessaly Medical School, 41110 Larissa, Greece. maspel@med.uth.gr

ABSTRACT
Tobacco smoking has been considered the most important risk factor for chronic obstructive pulmonary disease (COPD) development. However, not all smokers develop COPD and other environmental and genetic susceptibility factors underlie disease pathogenesis. Recent studies have indicated that the impairment of TLR signaling might play a crucial role in the development of emphysema. For this purpose we investigated the prevalence and any possible associations of common TLR polymorphisms (TLR2-R753Q, TLR4-D299G, and TLR4-T399I) in a group of 240 heavy smokers (>20 pack years), without overt atherosclerosis disease, of whom 136 had developed COPD and 104 had not. The presence of TLR4-T399I polymorphism was associated with a 2.4-fold increased risk for COPD development (P = .044), but not with disease stage or frequency of exacerbations. Considering that infections contribute to COPD and emphysema pathogenesis, our findings possibly indicate that dysfunctional polymorphisms of innate immune genes can affect the development of COPD in smokers. Although this finding warrants further investigation, it highlights the importance of impaired innate immunity towards COPD development.

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Related in: MedlinePlus

(a)  Representative digestions showing the TLR2-R753Q (A), TLR4-D299G (B), and TLR4-T399I (C) polymorphisms. M: 200 bp ladder molecular weight marker. Lanes 1–8: Patients with COPD; lane 9: negative PCR control. Samples without any polymorphism (1,3, 4,8) display undigested PCR products, 430 bp for the TLR2-R753Q, 249 bp for the TLR4-D299G, and 407 bp for the TLR4-T399I. Samples 5 and 7 are heterozygotes for the TLR2-R753Q polymorphism, whereas the TLR2-753Q allele contains a Sfc I restriction site resulting in 307 bp and 123 bp fragments. Samples 2 and 6 are double heterozygotes for both TLR4 polymorphisms. In particular, the TLR4-299G allele contains an NcoI restriction site resulting in 218 bp and 31 bp fragments, while the TLR4-399I allele contains a HinfI restriction site resulting in 375 bp and 28 bp fragments. The digestion products were analyzed on 2% of TBE agarose gels and the 28 bp and 31 bp fragments are not visible on agarose gels. (b) Representative sequencing analysis shows the presence of TLR2-R753Q, TLR4-D299G, and TLR4-T399I polymorphisms.
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fig1: (a) Representative digestions showing the TLR2-R753Q (A), TLR4-D299G (B), and TLR4-T399I (C) polymorphisms. M: 200 bp ladder molecular weight marker. Lanes 1–8: Patients with COPD; lane 9: negative PCR control. Samples without any polymorphism (1,3, 4,8) display undigested PCR products, 430 bp for the TLR2-R753Q, 249 bp for the TLR4-D299G, and 407 bp for the TLR4-T399I. Samples 5 and 7 are heterozygotes for the TLR2-R753Q polymorphism, whereas the TLR2-753Q allele contains a Sfc I restriction site resulting in 307 bp and 123 bp fragments. Samples 2 and 6 are double heterozygotes for both TLR4 polymorphisms. In particular, the TLR4-299G allele contains an NcoI restriction site resulting in 218 bp and 31 bp fragments, while the TLR4-399I allele contains a HinfI restriction site resulting in 375 bp and 28 bp fragments. The digestion products were analyzed on 2% of TBE agarose gels and the 28 bp and 31 bp fragments are not visible on agarose gels. (b) Representative sequencing analysis shows the presence of TLR2-R753Q, TLR4-D299G, and TLR4-T399I polymorphisms.

Mentions: Examples of the detection of TLR polymorphisms by PCR-RFLP are presented in Figure 1. Direct sequencing of 32 randomly chosen samples (5 heterozygotes for both TLR4 polymorphisms, 2 heterozygotes for the TLR2-R753Q, and 25 wild-type) confirmed the results of PCR-RFLP analysis. No one individual was homozygous for any TLR polymorphism. The allele and genotype frequencies of the TLR4-T399I SNP were significantly increased in patients with COPD when compared to normal smokers (P = .046 and P = .039, resp.). Moreover, an increased frequency of the TLR4-D299G allele in COPD was also observed but failed to reach statistical significance (P = .061). Considering the prevalence of the TLR2-R753Q, no significant difference between COPD patients and healthy smokers was observed (P = .117). Logistic regression analysis revealed that individuals carrying the TLR4-T399I polymorphism displayed a 2.4-fold increased risk to develop COPD (95% CI: 1.02–5.64, P = .044). Other variables associated with COPD development were age (P< .001) and pys (P< .001). Considering the impact of the other polymorphisms, no significant difference was observed (Table 2).


Association of TLR4-T399I polymorphism with chronic obstructive pulmonary disease in smokers.

Speletas M, Merentiti V, Kostikas K, Liadaki K, Minas M, Gourgoulianis K, Germenis AE - Clin. Dev. Immunol. (2010)

(a)  Representative digestions showing the TLR2-R753Q (A), TLR4-D299G (B), and TLR4-T399I (C) polymorphisms. M: 200 bp ladder molecular weight marker. Lanes 1–8: Patients with COPD; lane 9: negative PCR control. Samples without any polymorphism (1,3, 4,8) display undigested PCR products, 430 bp for the TLR2-R753Q, 249 bp for the TLR4-D299G, and 407 bp for the TLR4-T399I. Samples 5 and 7 are heterozygotes for the TLR2-R753Q polymorphism, whereas the TLR2-753Q allele contains a Sfc I restriction site resulting in 307 bp and 123 bp fragments. Samples 2 and 6 are double heterozygotes for both TLR4 polymorphisms. In particular, the TLR4-299G allele contains an NcoI restriction site resulting in 218 bp and 31 bp fragments, while the TLR4-399I allele contains a HinfI restriction site resulting in 375 bp and 28 bp fragments. The digestion products were analyzed on 2% of TBE agarose gels and the 28 bp and 31 bp fragments are not visible on agarose gels. (b) Representative sequencing analysis shows the presence of TLR2-R753Q, TLR4-D299G, and TLR4-T399I polymorphisms.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2822240&req=5

fig1: (a) Representative digestions showing the TLR2-R753Q (A), TLR4-D299G (B), and TLR4-T399I (C) polymorphisms. M: 200 bp ladder molecular weight marker. Lanes 1–8: Patients with COPD; lane 9: negative PCR control. Samples without any polymorphism (1,3, 4,8) display undigested PCR products, 430 bp for the TLR2-R753Q, 249 bp for the TLR4-D299G, and 407 bp for the TLR4-T399I. Samples 5 and 7 are heterozygotes for the TLR2-R753Q polymorphism, whereas the TLR2-753Q allele contains a Sfc I restriction site resulting in 307 bp and 123 bp fragments. Samples 2 and 6 are double heterozygotes for both TLR4 polymorphisms. In particular, the TLR4-299G allele contains an NcoI restriction site resulting in 218 bp and 31 bp fragments, while the TLR4-399I allele contains a HinfI restriction site resulting in 375 bp and 28 bp fragments. The digestion products were analyzed on 2% of TBE agarose gels and the 28 bp and 31 bp fragments are not visible on agarose gels. (b) Representative sequencing analysis shows the presence of TLR2-R753Q, TLR4-D299G, and TLR4-T399I polymorphisms.
Mentions: Examples of the detection of TLR polymorphisms by PCR-RFLP are presented in Figure 1. Direct sequencing of 32 randomly chosen samples (5 heterozygotes for both TLR4 polymorphisms, 2 heterozygotes for the TLR2-R753Q, and 25 wild-type) confirmed the results of PCR-RFLP analysis. No one individual was homozygous for any TLR polymorphism. The allele and genotype frequencies of the TLR4-T399I SNP were significantly increased in patients with COPD when compared to normal smokers (P = .046 and P = .039, resp.). Moreover, an increased frequency of the TLR4-D299G allele in COPD was also observed but failed to reach statistical significance (P = .061). Considering the prevalence of the TLR2-R753Q, no significant difference between COPD patients and healthy smokers was observed (P = .117). Logistic regression analysis revealed that individuals carrying the TLR4-T399I polymorphism displayed a 2.4-fold increased risk to develop COPD (95% CI: 1.02–5.64, P = .044). Other variables associated with COPD development were age (P< .001) and pys (P< .001). Considering the impact of the other polymorphisms, no significant difference was observed (Table 2).

Bottom Line: Recent studies have indicated that the impairment of TLR signaling might play a crucial role in the development of emphysema.For this purpose we investigated the prevalence and any possible associations of common TLR polymorphisms (TLR2-R753Q, TLR4-D299G, and TLR4-T399I) in a group of 240 heavy smokers (>20 pack years), without overt atherosclerosis disease, of whom 136 had developed COPD and 104 had not.Considering that infections contribute to COPD and emphysema pathogenesis, our findings possibly indicate that dysfunctional polymorphisms of innate immune genes can affect the development of COPD in smokers.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Histocompatibility, University of Thessaly Medical School, 41110 Larissa, Greece. maspel@med.uth.gr

ABSTRACT
Tobacco smoking has been considered the most important risk factor for chronic obstructive pulmonary disease (COPD) development. However, not all smokers develop COPD and other environmental and genetic susceptibility factors underlie disease pathogenesis. Recent studies have indicated that the impairment of TLR signaling might play a crucial role in the development of emphysema. For this purpose we investigated the prevalence and any possible associations of common TLR polymorphisms (TLR2-R753Q, TLR4-D299G, and TLR4-T399I) in a group of 240 heavy smokers (>20 pack years), without overt atherosclerosis disease, of whom 136 had developed COPD and 104 had not. The presence of TLR4-T399I polymorphism was associated with a 2.4-fold increased risk for COPD development (P = .044), but not with disease stage or frequency of exacerbations. Considering that infections contribute to COPD and emphysema pathogenesis, our findings possibly indicate that dysfunctional polymorphisms of innate immune genes can affect the development of COPD in smokers. Although this finding warrants further investigation, it highlights the importance of impaired innate immunity towards COPD development.

Show MeSH
Related in: MedlinePlus