Genetic Polymorphisms of Surfactant Protein D rs2243639, Interleukin (IL)-1β rs16944 and IL-1RN rs2234663 in Chronic Obstructive Pulmonary Disease, Healthy Smokers, and Non-Smokers

Liposomal sodium clodronate mitigates radiation-induced lung injury through macrophage depletion

Radiation-induced lung injury (RILI) is a severe complication arising from thoracic tumor radiotherapy, which constrains the possibility of increasing radiation dosage. Current RILI therapies provide only limited relief and may result in undesirable side effects. Therefore, there is an urgent demand for effective and low-toxicity treatments for RILI. Macrophages play a pivotal role in RILI, promoting inflammation in the initial stages and facilitating fibrosis in the later stages. Sodium clodronate, a bisphosphonate, can induce macrophage apoptosis when encapsulated in liposomes. In this study, we explored the potential of liposomal sodium clodronate (LC) as a specific agent for depleting macrophages to alleviate acute RILI. We assessed the impact of LC on macrophage consumption both in vitro and in vivo. In a mouse model of acute RILI, LC treatment group led to a reduction in alveolar macrophage counts, mitigated lung injury severity, and lowered levels of pro-inflammatory cytokines in both plasma and bronchoalveolar lavage fluid. Additionally, we further elucidated the specific effects and mechanism of LC on macrophages in vitro. Alveolar macrophages MHS cells were subjected to varying concentrations of LC (0, 50, 100, 200 μg/ml), and the results demonstrated its dose-dependent inhibition of cell proliferation and induction of apoptosis. Moreover, LC decreased the secretion of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α. Conditioned media from LC-treated macrophages protected alveolar epithelial cells MLE-12 from radiation-induced damage, as demonstrated by reduced apoptosis and DNA damage. These findings imply that LC-mediated macrophage depletion may present a promising therapeutic strategy for alleviating radiation-induced lung injury.

Association between single-nucleotide polymorphism of cytokines genes and chronic obstructive pulmonary disease: A systematic review and meta-analysis

Chronic obstructive pulmonary disease (COPD) is a common chronic inflammatory disease with high morbidity and mortality rates worldwide. Cytokines, which are the main regulators of immune responses, play crucial roles in inflammatory diseases such as COPD. Moreover, certain genetic variations can alter cytokine expression, and changes in cytokine level or function can affect disease susceptibility. Therefore, investigating the association between genetic variations and disease progression can be useful for prevention and treatment. Several studies have explored the association between common genetic variations in cytokine genes and COPD susceptibility. In this study, we summarized the reported studies and, where possible, conducted a systematic review and meta-analysis to evaluate the genetic association between various cytokines and COPD pathogenesis. We extracted relevant articles from PubMed and Google Scholar databases using a standard systematic search strategy. We included a total of 183 studies from 78 separate articles that evaluated 50 polymorphisms in 12 cytokine genes in this study. Our analysis showed that among all reported cytokine polymorphisms (including TNF-α, TGF-β, IL1, IL1RN, IL4, IL4R, IL6, IL10, IL12, IL13, IL17, IL18, IL27, and IL33), only four variants, including TNF-α-rs1800629, TGF-β1-rs6957, IL13-rs1800925, and IL6-rs1800796, were associated with the risk of COPD development. This updated meta-analysis strongly supports the association of TNF-α-rs1800629, TGF-β1-rs6957, IL13-rs1800925, and IL6-rs1800796 variants with a high risk of COPD.

Molecular Impact of Conventional and Electronic Cigarettes on Pulmonary Surfactant

The alveolar epithelium is covered by a non-cellular layer consisting of an aqueous hypophase topped by pulmonary surfactant, a lipo-protein mixture with surface-active properties. Exposure to cigarette smoke (CS) affects lung physiology and is linked to the development of several diseases. The macroscopic effects of CS are determined by several types of cell and molecular dysfunction, which, among other consequences, lead to surfactant alterations. The purpose of this review is to summarize the published studies aimed at uncovering the effects of CS on both the lipid and protein constituents of surfactant, discussing the molecular mechanisms involved in surfactant homeostasis that are altered by CS. Although surfactant homeostasis has been the topic of several studies and some molecular pathways can be deduced from an analysis of the literature, it remains evident that many aspects of the mechanisms of action of CS on surfactant homeostasis deserve further investigation.

PRKCH polymorphism is associated with rheumatoid arthritis in a Chinese population

Genetic factors have been widely considered to have a substantial effect on the susceptibility to rheumatoid arthritis (RA). The purpose of this study was to determine whether the four newly discovered polymorphisms in a genome-wide association study (GWAS) meta-analysis confer susceptibility to RA in a Chinese Han population. We conducted a case-control study involving 359 RA cases and 873 age-and gender-matched controls and performed genotyping of four single nucleotide polymorphisms (SNPs), rs227163, rs726288, rs3783782 and rs2469434, using the dye terminator-based SNaPshot method. Consequently, we detected significant differences of genotype distribution of rs3783782 in PRKCH between RA and controls. The minor allele frequencies (MAFs) of rs3783782 were significantly higher in RA patients compared to control subjects. Moreover, the rs227163 in TNFRSF9 had higher MAFs in male RA compared with male controls. In addition, the polymorphism of rs3783782 in PRKCH was significantly associated with RA susceptibility (OR = 1.67, 95% CI = 1.32-2.11, p = 1.32 × 10^-5). After stratification by gender, the minor (A) allele was strongly associated with increased risk for RA in males (OR = 1.87, 95% CI = 1.34-2.60; p = 1.62 × 10^-4) and in females (OR = 1.51, 95% CI = 1.08-2.10; p = 0.014). For rs227163, the minor (C) allele was found to be associated with RA risk only in males (OR = 1.34, 95% CI = 1.02-1.75; p = 0.036). These findings for the first time confirmed that rs3783782 in PRKCH was associated with RA susceptibility in a Chinese population, and rs227163 in TNFRSF9 was associated with RA risk in Chinese males; these SNPs may serve as genetic markers for RA.

Effects of ALOX5, IL6R and SFTPD gene polymorphisms on the risk of lung cancer: A case-control study in China

BACKGROUND

ALOX5, IL6R and SFTPD are all immune related genes that may be involved in the development of lung cancer. We sought to explore the effect of polymorphisms of these genes on the risk of lung cancer.

METHODS

Six single nucleotide polymorphisms (SNPs) were genotyped using a MassARRAY platform in a case-control cohort including 550 patients with lung cancer and 550 healthy controls.

RESULTS

The rs4845626-T and rs4329505-C alleles were associated with a decreased risk of lung cancer (p < 0.001), while the rs745986-G and rs2245121-A alleles were correlated with an increased risk of lung cancer (p < 0.01). The rs4845626-GT/GG and rs4329505-TC genotypes were protective against lung cancer (p < 0.001). However, the rs745986-AG and rs2245121-AG/AA genotypes were associated with an increased risk of lung cancer (p < 0.01). Stratification analysis showed that the rs4845626 and rs4329505 polymorphisms of IL6R were associated with a reduced risk of lung cancer in both smokers and nonsmokers (p < 0.05). However, rs892690, rs745986 and rs2115819 of ALOX5 were associated with an increased risk of disease in nonsmokers, while rs2245121 of SFTPD was correlated with a higher risk of disease in smokers (p < 0.05).

CONCLUSION

Our results provide candidate SNPs for early screening for lung cancer and new clues for further study of the pathogenesis of the disease.

Association between chronic obstructive pulmonary disease and interleukins gene variants: A systematic review and meta-analysis

Interleukins are cytokines involved in systemic inflammation and immune system regulation. Many studies have investigated the association between common genetic variations in interleukin-coding genes and COPD susceptibility. In this study, a systematic review and meta-analysis was performed to evaluate the association between interleukin gene variations and COPD pathogenesis. Association studies were retrieved from PubMed and Google Scholar databases using the standard systematic search strategy. A total of 26 different studies evaluating eight polymorphisms in four interleukin genes were included in this study. In overall comparisons, IL1β-rs16944, -rs1143627, -rs1143634, IL13-rs20541 polymorphisms were found not to be associated with the increased risk for developing COPD. However, IL1RN-rs2234663 and IL13-rs1800925 showed a strong association with COPD. We showed that the CC genotype carriers of the IL6-rs1800795 are at significantly higher risk of developing COPD (OR = 1.31, 95% CI: 1.04-1.64, P = 0.01) compared to GG carriers. In case of IL6-rs1800796, individuals with CC and CG genotypes showed a lower risk to develop COPD (OR = 0.46, 95%CI: 0.32-0.66, P > 0.00). This updated meta-analysis strongly supports the association of IL1RN-rs2234663, IL6-rs1800795, -rs1800795 and IL13-rs1800925 variants with COPD.

Association of Surfactant-Associated Protein D Gene Polymorphisms with the Risk of COPD: a Meta-Analysis

The relationship between surfactant-associated protein D polymorphisms and chronic obstructive pulmonary disease risk remains controversial. This article is the first to systematically evaluate this relationship. A comprehensive worldwide search was conducted for relevant literature on surfactant-associated protein D gene mutations and chronic obstructive pulmonary disease risk prediction. Study quality was evaluated using the Newcastle-Ottawa scale. After four genetic models (the allele, additive, recessive, and dominant models) were identified, odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were applied in this meta-analysis. The meta-analysis included 659 individuals in the case group and 597 in the control group. In the Asian population, none of the four genetic models revealed any significant association between rs2243639 genotype and the risk of chronic obstructive pulmonary disease. In Caucasians, however, the recessive model exhibited significant risk associated with rs2243639. Furthermore, there was a significant association between rs721917 genotype and the risk of chronic obstructive pulmonary disease in the Asian population. In contrast, none of the four gene models revealed any significant risk associated with this gene in the Caucasian population. This meta-analysis suggests that rs2243639 is not related to the risk of chronic obstructive pulmonary disease in the Asian population but is related to this risk in the Caucasian population. Regarding rs721917, the T allele may increase the risk of chronic obstructive pulmonary disease in the Asian population.

Genetic Association of Pulmonary Surfactant Protein Genes, SFTPA1, SFTPA2, SFTPB, SFTPC, and SFTPD With Cystic Fibrosis

Surfactant proteins (SP) are involved in surfactant function and innate immunity in the human lung. Both lung function and innate immunity are altered in CF, and altered SP levels and genetic association are observed in Cystic Fibrosis (CF). We hypothesized that single nucleotide polymorphisms (SNPs) within the SP genes associate with CF or severity subgroups, either through single SNP or via SNP-SNP interactions between two SNPs of a given gene (intragenic) and/or between two genes (intergenic). We genotyped a total of 17 SP SNPs from 72 case-trio pedigree (SFTPA1 (5), SFTPA2 (4), SFTPB (4), SFTPC (2), and SFTPD (2)), and identified SP SNP associations by applying quantitative genetic principles. The results showed (a) Two SNPs, SFTPB rs7316 (p = 0.0083) and SFTPC rs1124 (p = 0.0154), each associated with CF. (b) Three intragenic SNP-SNP interactions, SFTPB (rs2077079, rs3024798), and SFTPA1 (rs1136451, rs1059057 and rs4253527), associated with CF. (c) A total of 34 intergenic SNP-SNP interactions among the 4 SP genes to be associated with CF. (d) No SNP-SNP interaction was observed between SFTPA1 or SFTPA2 and SFTPD. (e) Equal number of SNP-SNP interactions were observed between SFTPB and SFTPA1/SFTPA2 (n = 7) and SP-B and SFTPD (n = 7). (f) SFTPC exhibited significant SNP-SNP interactions with SFTPA1/SFTPA2 (n = 11), SFTPB (n = 4) and SFTPD (n = 3). (g) A single SFTPB SNP was associated with mild CF after Bonferroni correction, and several intergenic interactions that are associated (p < 0.01) with either mild or moderate/severe CF were observed. These collectively indicate that complex SNP-SNP interactions of the SP genes may contribute to the pulmonary disease in CF patients. We speculate that SPs may serve as modifiers for the varied progression of pulmonary disease in CF and/or its severity.

Correlation of vitamin D binding protein gene polymorphism and protein levels in chronic obstructive pulmonary disease compared with non-chronic obstructive pulmonary disease subjects

AIM

The risk of vitamin D binding protein (DBP) variations in chronic obstructive pulmonary disease (COPD) compared with non-COPD Thai males were investigated.

MATERIALS & METHODS

The rs7041 and rs4588 polymorphisms of the DBP gene and protein level were measured in 136 COPD and 68 non-COPD Thai males.

RESULTS

In the COPD group, GC1-1 gave increased forced expiratory volume at 1 s % predicted compared with GC1-2 but with no significant difference. Significantly lower average DBP serum levels were observed in COPD than non-COPD subjects. Positive correlation between serum DBP and forced expiratory volume at 1 s % predicted was observed in non-COPD subjects.

DISCUSSION & CONCLUSION

DBP variations might be associated with risk factors in COPD caused by both inflammatory and vitamin D circulation processes.

Surfactant Protein D in Respiratory and Non-Respiratory Diseases

Surfactant protein D (SP-D) is a multimeric collectin that is involved in innate immune defense and expressed in pulmonary, as well as non-pulmonary, epithelia. SP-D exerts antimicrobial effects and dampens inflammation through direct microbial interactions and modulation of host cell responses via a series of cellular receptors. However, low protein concentrations, genetic variation, biochemical modification, and proteolytic breakdown can induce decomposition of multimeric SP-D into low-molecular weight forms, which may induce pro-inflammatory SP-D signaling. Multimeric SP-D can decompose into trimeric SP-D, and this process, and total SP-D levels, are partly determined by variation within the SP-D gene, SFTPD. SP-D has been implicated in the development of respiratory diseases including respiratory distress syndrome, bronchopulmonary dysplasia, allergic asthma, and chronic obstructive pulmonary disease. Disease-induced breakdown or modifications of SP-D facilitate its systemic leakage from the lung, and circulatory SP-D is a promising biomarker for lung injury. Moreover, studies in preclinical animal models have demonstrated that local pulmonary treatment with recombinant SP-D is beneficial in these diseases. In recent years, SP-D has been shown to exert antimicrobial and anti-inflammatory effects in various non-pulmonary organs and to have effects on lipid metabolism and pro-inflammatory effects in vessel walls, which enhance the risk of atherosclerosis. A common SFTPD polymorphism is associated with atherosclerosis and diabetes, and SP-D has been associated with metabolic disorders because of its effects in the endothelium and adipocytes and its obesity-dampening properties. This review summarizes and discusses the reported genetic associations of SP-D with disease and the clinical utility of circulating SP-D for respiratory disease prognosis. Moreover, basic research on the mechanistic links between SP-D and respiratory, cardiovascular, and metabolic diseases is summarized. Perspectives on the development of SP-D therapy are addressed.

Impact of air quality guidelines on COPD sufferers

Background

COPD is one of the leading causes of morbidity and mortality in both high- and low-income countries and a major public health burden worldwide. While cigarette smoking remains the main cause of COPD, outdoor and indoor air pollution are important risk factors to its etiology. Although studies over the last 30 years helped reduce the values, it is not very clear if the current air quality guidelines are adequately protective for COPD sufferers.

Objective

This systematic review was to summarize the up-to-date literature on the impact of air pollution on the COPD sufferers.

Methods

PubMed and Google Scholar were utilized to search for articles related to our study’s focus. Search terms included “COPD exacerbation”, “air pollution”, “air quality guidelines”, “air quality standards”, “COPD morbidity and mortality”, “chronic bronchitis”, and “air pollution control” separately and in combination. We focused on articles from 1990 to 2015. We also used articles prior to 1990 if they contained relevant information. We focused on articles written in English or with an English abstract. We also used the articles in the reference lists of the identified articles.

Results

Both short-term and long-term exposures to outdoor air pollution around the world are associated with the mortality and morbidity of COPD sufferers even at levels below the current air quality guidelines. Biomass cooking in low-income countries was clearly associated with COPD morbidity in adult nonsmoking females.

Conclusion

There is a need to continue to improve the air quality guidelines. A range of intervention measures could be selected at different levels based on countries’ socioeconomic conditions to reduce the air pollution exposure and COPD burden.

Interaction of TLR-IFN and HLA polymorphisms on susceptibility of chronic HBV infection in Southwest Han Chinese

BACKGROUND & AIMS

The toll-like receptor-interferon (TLR-IFN) signalling pathway plays a crucial role in HBV infection. Human leucocyte antigen (HLA) polymorphisms are associated with chronic HBV infection by genome wide association study (GWAS). We aimed to explore interaction between TLR-IFN and HLA gene polymorphisms in susceptibility of chronic HBV infection.

METHODS

In the Chinese Southwest Han population, 1191 chronic HBV infection patients and 273 HBV clearance were selected. A total of 39 single nucleotide polymorphism loci in 23 genes of the TLR-IFN pathway and four HLA polymorphism loci associated with chronic HBV infection identified by GWAS were selected for genotyping. SNPStats, QVALUE, and multifactor dimensionality reduction were used for statistical analysis.

RESULTS

A significant association was seen in several of the TLR-IFN pathway genes, TLR9 rs352140 (OR = 0.70, P = 0.0088), IL1B rs16944 (OR = 0.67, P = 0.016), IL12B rs3212227 (OR = 1.38, P = 0.021), IFNGR1 rs3799488 (OR = 1.48, P = 0.0048), IFNGR2 rs1059293 (OR = 0.27, P = 0.011), MX1 rs467960 (OR = 0.68, P = 0.022), as well as four loci in HLA, rs3077 (OR = 0.55, P < 0.0001), rs2856718 (OR = 0.60, P = 4e-04), rs9277535 (OR = 0.54, P < 0.0001) and rs7453920 (OR = 0.43, P < 0.0001). A synergistic relationship was seen between rs9277535 and rs16944 (0.13%), rs1143623 and rs6613 (0.10%). The combination of rs9277535 in HLA and rs16944 in IL1B was the best model to predict chronic HBV infection (testing accuracy = 0.6040, P = 0.0010, cross-validation consistency = 10/10).

CONCLUSIONS

TLR-IFN pathway gene polymorphisms are associated with chronic HBV infection. Interactions with polymorphisms in these genes may be one mechanism by which HLA polymorphisms influence susceptibility to chronic HBV infection, as specific single nucleotide polymorphism combinations are highly predictive of chronic HBV infection.

Vitamin D-binding protein gene polymorphisms and chronic obstructive pulmonary disease susceptibility: A meta-analysis

The vitamin D-binding protein (VDBP) genetic polymorphisms have been associated with chronic obstructive pulmonary disease (COPD). A number of studies have been conducted to investigate the combined effects of the VDBP gene (GC) rs7041 and rs4588 polymorphisms on the COPD risk. However, the results obtained are inconclusive. The present meta-analysis aimed to investigate whether GC polymorphisms may be a potential risk factor for COPD. The Web of Science, PubMed, Google Scholar, Embase, Cochrane Library, China National Knowledge Infrastructure and Wanfang Database were searched from inception until June 1, 2014. The meta-analysis was performed using the STATA 12.0 software. Twelve case-control studies, including 2,937 subjects, met the inclusion criteria. Overall, a significantly increased risk was detected in populations of GC*1F homozygotes, whereas no associations between other GC polymorphisms and COPD risk were detected. According to ethnicity, the results demonstrated that the GC*1F homozygotes may be a risk factor for COPD and the GC*2 homozygotes may be a protective factor against COPD in the Asian population. However, similar associations were not observed among the Caucasian population. In conclusion, the current meta-analysis indicates that the GC*1F homozygotes may be a risk factor for COPD and the GC*2 homozygotes may be a protective factors against COPD in the Asian population.

Association between the IL1B, IL1RN polymorphisms and COPD risk: a meta-analysis

The interleukin-1 (IL-1) gene polymorphisms have been implicated in chronic obstructive pulmonary disease (COPD) risk, but results are controversial. We aimed to conduct a meta-analysis to address this issue. Odds ratio (OR) and 95% confidence interval (CI) were used to investigate the strength of the association. The meta-analysis revealed no association between the IL1B (−511), (−31), (+3954) polymorphisms and COPD risk. However, stratification by ethnicity indicated that the T allele carriers of the IL1B (−511) polymorphism and the C allele carriers of the IL1B (−31) variant were associated with an increased risk for developing COPD in East Asians (OR = 1.61, 95% CI: 1.13–2.31, P_z = 0.009 and OR = 1.55, 95% CI: 1.14–2.11, P_z = 0.006, respectively). The meta-analysis revealed a significant association between the IL1RN (VNTR) polymorphism and COPD risk in all study subjects and East Asians under homozygote model (22 vs. LL: OR = 3.16, 95% CI: 1.23–8.13, P_z = 0.017 and OR = 3.20, 95% CI: 1.13–9.12, P_z = 0.029, respectively). Our meta-analysis suggests that the IL1B (−511), (−31) and IL1RN (VNTR) polymorphisms are associated with COPD risk in East Asians. There is no association between the IL1B(+3954) polymorphism and COPD risk. Further studies should be performed in other ethnic groups besides East Asians.