Polymorphisms in the transforming growth factor-beta1 gene and the risk of asthma: A meta-analysis

Polymorphisms in MicroRNA Target Sites of TGF-β Signaling Pathway Genes and Susceptibility to Allergic Rhinitis

BACKGROUND

The polymorphisms inside microRNA target sites locating in the 3'-UTR region may introduce the micro-RNA-binding changes, which may regulate the gene expression and correlate with the potential diseases.

OBJECTIVES

We aimed to investigate whether the polymorphisms in microRNA target sites of transforming growth factor beta (TGF-β) signaling pathway genes are associated with the susceptibility of mite-sensitized allergic rhinitis (AR) in a Han Chinese population.

METHODS

In this case-control study, 454 AR patients and 448 healthy controls were recruited. Three HapMap single-nucleotide polymorphisms (SNPs) were mapped to putative microRNA recognition sites and genotyped by TaqMan allelic discrimination assay.

RESULTS

The genotype and allele frequencies of 3 SNPs (rs1590 in TGFBR1; rs1434536 and rs17023107 in BMPR1B) showed lack of significant association with AR. However, in the subgroup analysis, the TG, GG, and TG/GG genotypes of rs1590 exhibited significantly increased risk of AR in the male subgroup (TG: adjusted OR = 1.57, 95% CI = 1.08-2.31; GG: adjusted OR = 1.76, 95% CI = 1.09-2.86; TG/GG: adjusted OR = 1.62, 95% CI = 1.13-2.33). The CT genotypes of rs17023107 might have potential to protect against AR in the patients age of <15 years (adjusted OR = 0.37, 95% CI = 0.14-0.95) and the males (adjusted OR = 0.48, 95% CI = 0.25-0.95). No significant association was found between SNPs and the total serum IgE level.

CONCLUSIONS

In a Han Chinese population, stratified by age and gender, susceptibility to mite-sensitized AR may be associated with 2 SNPs (rs1590 and rs17023107) in microRNA target sites of TGF-β signaling pathway genes.

T1 polymorphism in a disintegrin and metalloproteinase 33 (ADAM33) gene may contribute to the risk of childhood asthma in Asians

OBJECTIVE

Polymorphisms in ADAM33 gene have been implicated in susceptibility to the risk of childhood asthma. However, the results remain controversial. We performed meta-analyses to clarify the relationship between them.

METHODS

Relevant articles were searched in PubMed, Embase, Wanfang, and China National Knowledge Infrastructure. The Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the associations.

RESULTS

Fourteen studies with five ADAM33 polymorphisms (F + 1, T1, T2, S2, and V4) were identified, involving 2687 cases and 2996 controls. ADAM33 F + 1, T2, and T1 polymorphisms showed significant associations with asthma risks in the overall and Caucasian children, Asian children, and Caucasian and Chinese children, respectively; however, these significant results were unstable in sensitivity analysis. T1 revealed significant and stable associations with asthma risks among Asian children in the dominant (OR = 2.00, 95% CI = 1.40-2.87, P = 0.0002) and codominant (OR = 3.06, 95% CI = 1.71-5.50, P = 0.0002) models; in cumulative meta-analyses, these significant results were robust. Concerning S2 or V4 polymorphism, no significant associations were observed.

CONCLUSION

These findings demonstrate that ADAM33 T1 polymorphism might be a potential susceptible predictor of asthma for Asian children. Further functional studies between this polymorphism and asthma risks are warranted.

An updated meta-analysis of transforming growth factor-β1 gene: Three well-characterized polymorphisms with asthma

The association between TGF-β1 polymorphisms and asthma risk has been widely reported, but results were controversial. We performed this meta-analysis based on the Preferred Reporting Items for Systematic Reviews and meta-analyses statement (PRISMA). Electronic database of Pub Med, Web of Science, CBM, and CNKI were searched for eligible articles published up to September, 2013. The effect summary odds ratio (OR) and 95% confidence intervals were obtained. Finally, a total of 20 articles were identified, 17 studies with 3694 cases and 5613 controls for C-509T polymorphism, 7 studies with 1109 cases and 1098 controls for T869C polymorphism and 5 studies with 849 cases and 829 controls for G915C polymorphism. For C-509T, significant associations with asthma were found in Asians (TT+TC vs. CC: P=0.004, OR=1.43, 95%CI=1.12-1.81, P_{heterogeneity}=0.001) and in Caucasians (P=0.05, OR=1.16, 95%CI=1.00-1.34, P_{heterogeneity}=0.36). With respect to T869C, a small significant association was observed in overall analysis of allele contrasts(C vs. T: OR=1.14, 95%CI: 1.01-1.29, P=0.03) and homozygote comparison (CC vs. TT: OR=1.29, 95%CI: 1.00-1.65, P=0.05), but no significant risks were found among Caucasian population and Asian population. For G915C polymorphism, no significant association with asthma risk was demonstrated in overall analysis and subgroup analyses according to ethnicity for all genetic models. This meta-analysis suggested that TGF-β1 C-509T and T869C polymorphisms may be risk factors for asthma.

Effects of Two Common Promoter Polymorphisms of Transforming Growth Factor-β1 on Breast Cancer Risks in Ahvaz, West South of Iran

BACKGROUND

Transforming growth factor-β1 (TGF-β1) has a critical role in breast cancer initiation and progression.

OBJECTIVES

We have investigated the possible differences in two promoter polymorphisms (-509C/T and -800G/A) of TGF-β1 gene between breast cancer cases and controls.

PATIENTS AND METHODS

A total of 100 patients with confirmed breast cancer and 100 subjects without breast cancer was selected. Two promoter polymorphisms (-509C/T and -800G/A) of TGF-β1 gene were genotyped using PCR-based restriction fragment length polymorphism (RFLP) method.

RESULTS

The allele frequencies were 63% for C allele and 37% for T allele of SNP -509C/T and 66% for G allele and 34% for A allele of SNP -800G/A. Although no significant difference has observed between two groups, according to the genotype distribution, However, the TT genotype of -509 and AA genotype of -800 was significantly associated with breast cancer risk [odds ratio (OR) = 2.409; 95% confidence interval (CI) = 1.087 - 5.337, P = 0.030; and OR = 2.383; CI = 1.039 - 5.40, P = 0.040, respectively]. In addition, a multinomial logistic regression model shown, homozygous of -800 G/A (OR = 0.570; 95% CI = 0.362 - 0.896, P = 0.015); and HDL-C (OR = 0.935; 95% CI = 0.906 - 0.965, P < 0.001) were the selected variables associated with the presence of breast cancer. Haplotype analysis has shown no significant association between TGF-β1 haplotypes and breast cancer risk.

CONCLUSIONS

Our results indicated that among two promoter polymorphisms of the TGF-β1gene, -800G/A compared to -509C/T is more associated with breast cancer.

Immunization against TGF-β1 reduces collagen deposition but increases sustained inflammation in a murine asthma model

Transforming growth factor (TGF)-β1 is involved in the processes of airway inflammation and remodeling; however, its reported roles in asthma pathogenesis are controversial. We sought both to investigate the effects of active immunization targeting TGF-β1 on allergen-induced airway inflammatory responses and to evaluate its possible application for asthma treatment. BALB/c mice were immunized with a virus-like-particle (VLP) vaccine presenting a TGF-β1 peptide. For the preventive intervention of acute allergic airway inflammation, immunization was conducted before sensitization and challenges with ovalbumin (OVA), and for the therapeutic treatment of chronic inflammatory responses, immunization was initiated after inflammatory responses were established. Preventive immunization with VLPs led to increased proinflammatory IL-4, IL-13, and IL-33 levels in the bronchoalveolar lavage fluids (BALF) with no significant effects on lung tissue inflammation and airway goblet cell hyperplasia. Therapeutic treatment showed that at 24 h after the fourth 2-day challenge with OVA following 2 intraperitoneal sensitizations, airway subepithelial collagen deposition was significantly ameliorated in vaccinated mice, whereas the lung histology and cytokine profile in the BALF were not changed. In contrast, after a 4-week recovery from the last OVA challenge, the vaccinated mice's collagen deposition remained reduced, but they sustained lung-tissue inflammation and goblet-cell hyperplasia; elevated IL-13, TNF, and IFN-γ levels in the BALF; and increased airway resistance, tissue resistance, and tissue elastance. In a conclusion, the role of TGF-β1 is complicated in allergic airway inflammatory responses. It is important to make a careful assessment in accordance with specific disease conditions when targeting TGF-β1 for a therapeutic purpose.

Association of transforming growth factor-Beta 1 promoter variant -509 c/t with bronchial asthma in South Indian population

Transforming growth factor-beta 1 (TGF-β1) is a multifunctional cytokine that plays a pivotal role in airway remodeling observed in the asthmatic airways. C to T base substitution at -509 promoter position in the TGF-β1 gene leads to its increased expression which contributes to airway remodeling in bronchial asthma. We sought to evaluate the association of TGF-β1 -509 C/T promoter variant with clinical asthma and varying degrees of disease severity. Three hundred and eighty-two clinically diagnosed asthma patients and 410 healthy controls were enrolled for the study. Patients were classified into severity classes according to the Global Initiative for Asthma (GINA) guidelines. TGF-β1 -509 C/T genotyping was carried out by amplification refractory mutation system polymerase chain reaction (ARMS-PCR) technique. In the present study, we found significantly higher frequency of TT genotype in asthma patients compared to controls (for TT vs. CC, p = 0.020). In addition, a significant difference was observed in the frequency of C and T allele in patients and controls (for T vs. C, p = 0.029). The heterozygous "CT" genotype was higher in moderate and severe asthmatics compared to mild subset of patients (for mild vs. moderate, p = 0.037). However, there was no significant distribution and association of variant allele with the severity subsets.

Single nucleotide polymorphisms predisposing to asthma in children of Mauritian Indian and Chinese Han ethnicity

Our objective was to investigate the distributions of six single nucleotide polymorphisms (SNPs) MS4A2 E237G, MS4A2 C-109T, ADRB2 R16G, IL4RA I75V, IL4 C-590T, and IL13 C1923T in Mauritian Indian and Chinese Han children with asthma. This case-control association study enrolled 382 unrelated Mauritian Indian children, 193 with asthma and 189 healthy controls, and 384 unrelated Chinese Han children, 192 with asthma and 192 healthy controls. The SNP loci were genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism for the Chinese Han samples and TaqMan real-time quantitative PCR for the Mauritian Indian samples. In the Mauritian Indian children, there was a significant difference in the distribution of IL13 C1923T between the asthma and control groups (P=0.033). The frequency of IL13 C1923T T/T in the Mauritian Indian asthma group was significantly higher than in the control group [odds ratio (OR)=2.119, 95% confidence interval=1.048-4.285]. The Chinese Han children with asthma had significantly higher frequencies of MS4A2 C-109T T/T (OR=1.961, P=0.001) and ADRB2 R16G A/A (OR=2.575, P=0.000) than the control group. The IL13 C1923T locus predisposed to asthma in Mauritian Indian children, which represents an ethnic difference from the Chinese Han population. The MS4A2 C-109T T/T and ADRB2 R16G A/A genotypes were associated with asthma in the Chinese Han children.

CC16 gene A38G polymorphism and susceptibility to asthma: an updated meta-analysis

OBJECTIVE

To comprehensively evaluate the association between the CC16 gene A38G polymorphism and the risk of asthma.

METHODS

Studies were retrieved from databases including PubMed, EMBASE, Web of Science and the Chinese Biomedical Literature Database according to the inclusive and exclusive criteria. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations.

MATERIALS

Fifteen case-control studies with 1,623 cases and 3,294 controls were recruited for the analysis of the association between the CC16 gene A38G polymorphism and the risk of asthma.

RESULTS

The overall ORs showed no significant associations between the CC16 gene A38G polymorphism and the risk of asthma (AA vs. GG: OR=1.04, 95%CI=0.86-1.25; AG vs. GG: OR=1.08, 95%CI=0.94-1.24; AA + AG vs. GG: OR=1.07, 95%CI=0.94-1.22; AA vs. AG + GG: OR=1.01, 95%CI=0.85-1.19; A vs. G: OR=1.04, 95%CI=0.95-1.14). Moreover, similar results were obtained in the subgroup analysis stratified by ethnicity (Asian: AG vs. GG: OR=1.02, 95%CI=0.87-1.21; Caucasian: AG vs. GG: OR=1.22, 95%CI=0.94-1.57) and age (Child: AG vs. GG: OR=1.21, 95%CI=0.84-1.74; Adult: AG vs. GG: OR=1.06, 95%CI=0.91-1.23).

CONCLUSION

CC16 gene A38G polymorphism is not associated with the risk of asthma.

Polymorphisms of tumor necrosis factor-α, transforming growth factor-β, and interleukin-10 in asthma associated with olive pollen sensitization

Sensitization to specific olive pollen-allergens (Ole e 2 and 10) has been correlated with a clinical pattern of asthma. This study analyzes the association between several polymorphims of TNFA (G-308A, C-857T, and C-1031T), IL10 (C-571A and A-1117G), and TGFB (C-509-T) and these sensitizations. These polymorphisms were genotyped by allelic discrimination, in olive pollen-allergic patients (phenotyped for specific Ole e 2 and 10 sensitizations) and healthy controls. Levels of serum-soluble cytokines were correlated with specific genotypes and clinical phenotypes. The results showed that heterozygous TGFB C-509T genotype, besides having the lowest sera TGF- levels, was significantly increased in olive pollen-allergic patients compared with controls. According specific sensitizations, CC genotype of IL10 C-571A could be a protective factor for Ole e 2 sensitization and mainly for asthmatic Ole e 2 sensitized patients compared with asthmatic non-Ole e 2 sensitized patients (OR: 0.26, P = 0.008). In contrast, heterozygous CA genotype was increased in Ole e 2 asthmatic subjects compared to asthmatic non-Ole e 2 sensitized patients. Lastly, heterozygous TNFA G-308A genotype was associated with Ole e 10 sensitization (OR: 2.5, P = 0.04). In conclusion, these results suggest a role of TGF-β1 in olive-pollen sensitization and TNF-α and IL-10 genotypes in the asthma induced by specific olive-pollen allergens.

Gene susceptibility in Iranian asthmatic patients: a narrative review

As environmental factors are important in the development of asthma, genetic factors could have a critical role in the expression of the disease. Hence, we carried out a systematic review to assess the susceptible genes for asthma in Iranian population. We conducted a literature search by using the electronic database PubMed, Biological Abstracts Web of Science, Current Contents Connect, Cinahl, ScienceDirect, Scopus, IranMedex, and Scientific Information Database to identify articles that evaluated the association between genetic variants and the risk of asthma in Iranian population (until April 30, 2012). The search terms were used include: Asthma and gene in combination with Iran for international database. The following criteria were used for selecting literatures in this review: The study should evaluate the association between gene polymorphism and risk of asthma in Iranian population, and the study should be a case-control design with normal subject as ac control group that published in a journal. Finally, 14 case-control studies were extracted from local and international database. In this study, we reviewed 38 polymorphisms in 19 genes. Polymorphism in interleukin-13 (IL-13), IL-10, IL-1, IL-2, IL-12, E-Selectin, S128R and Exon 9 Vitamin D Receptor were susceptible for asthma and polymorphism in chemokine receptor 5, transforming growth factor-a (TGF-a), Intron 8 of the Vitamin D Receptor, angiotensin-converting enzyme gene, IL-6 and interferon-c were not susceptible for asthma in Iranian population. Polymorphism in IL-4, tumor necrosis factor-α and TGF-b had inconsistent findings. This systematic review indicated that three polymorphisms (IL-13, IL-10, and IL-1) are associated with risk of asthma in Iranian population.

Association of insulin degrading enzyme gene polymorphisms with Alzheimer's disease: a meta-analysis

Alzheimer's disease (AD) is a chronic degenerative disorder. It is caused by both genetic and environmental factors. The association of Insulin Degrading Enzyme (IDE) genotypes rs4646953, rs2251101 and rs1544210 with AD has been detected, but the findings were conflicted, however, Apolipoprotein-E (APOE)-ε4 allele has been observed as a genetic risk factor for AD. To investigate the issue, a meta-analysis was performed. We searched PubMed, Springer Link, AlzGene and CNKI for relevant literatures published by June 2013. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to explore the significant association. A total of 11 studies comprising 5771 cases and 5474 controls were considered in final meta-analysis. We found that weak connections existed between rs4646953 (TT vs. CC: z = 2.24, p = 0.025, OR = 1.536) and AD, but no significant associations have been found between other IDE gene single nucleotide polymorphisms of rs4646953, rs2251101 and rs1544210 with AD. We certified that APOE-ε4 allele was still be a suspected factor to AD. There was no evidence for obvious publication bias in overall meta-analysis. Furthermore, larger-scale randomized controlled trials are necessary to validate the association between IDE gene polymorphisms with AD.

Transforming growth factor β and severe asthma: a perfect storm

Asthma is a chronic inflammatory airway disease involving complex interplay between resident and infiltrative cells, which in turn are regulated by a wide range of host mediators. Identifying useful biomarkers correlating with clinical symptoms and degree of airway obstruction remain important to effective future asthma treatments. Transforming growth factor β (TGF-β) is a major mediator involved in pro-inflammatory responses and fibrotic tissue remodeling within the asthmatic lung. Its role however, as a therapeutic target remains controversial. The aim of this review is to highlight its role in severe asthma including interactions with adaptive T-helper cells, cytokines and differentiation through regulatory T-cells. Associations between TGF-β and eosinophils will be addressed and the effects of genetic polymorphisms of the TGF-β1 gene explored in the context of asthma. We highlight TGF-β1 as a potential future therapeutic target in severe asthma including its importance in identifying emerging clinical phenotypes in asthmatic subjects who may be suitable for individualized therapy through TGF-β modulation.

Transient early wheeze and lung function in early childhood associated with chronic obstructive pulmonary disease genes

BACKGROUND

It has been hypothesized that a disturbed early lung development underlies the susceptibility to chronic obstructive pulmonary disease (COPD). Little is known about whether subjects genetically predisposed to COPD show their first symptoms or reduced lung function in childhood.

OBJECTIVE

We investigated whether replicated genes for COPD associate with transient early wheeze (TEW) and lung function levels in 6- to 8-year-old children and whether cigarette smoke exposure in utero and after birth (environmental tobacco smoke [ETS]) modifies these effects.

METHODS

The association of COPD-related genotypes of 20 single nucleotide polymorphisms in 15 genes with TEW, FEV1, forced vital capacity (FVC), and FEV1/FVC ratio was studied in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort (n = 1996) and replicated in the Child, parents and health: lifestyle and genetic constitution (KOALA) and Avon Longitudinal Study of Parents and Children (ALSPAC) cohorts.

RESULTS

AGER showed replicated association with FEV1/FVC ratio. TNS1 associated with more TEW in PIAMA and lower FEV1 in ALSPAC. TNS1 interacted with ETS in PIAMA, showing lower FEV1 in exposed children. HHIP rs1828591 interacted with cigarette smoke exposure in utero in PIAMA and with ETS in ALSPAC, with lower lung function in nonexposed children. SERPINE2, FAM13A, and MMP12 associated with higher FEV1 and FVC, and SERPINE2, HHIP, and TGFB1 interacted with cigarette smoke exposure in utero in PIAMA only, showing adverse effects of exposure on FEV1 being limited to children with genotypes conferring the lowest risk of COPD.

CONCLUSION

Our findings indicate relevant involvement of at least 3 COPD genes in lung development and lung growth by demonstrating associations pointing toward reduced airway caliber in early childhood. Furthermore, our results suggest that COPD genes are involved in the infant's lung response to smoke exposure in utero and in early life.

Association of ADAM33 gene polymorphisms with asthma in the Uygur population of China

Asthma is one of the most common chronic respiratory diseases, affecting ∼300 million children and adults worldwide. Previous studies identified a disintegrin and metalloprotease domain 33 (ADAM33) as an important susceptibility gene for asthma in patients of different nationalities; however, it is unknown whether this relationship exists in ethnically diverse populations. The present study focused on the association between single-nucleotide polymorphisms (SNPs) of the ADAM33 gene and asthma in the Uygur population of China. Three SNPs of ADAM33 (T1, S+1 and F+1) were genotyped in a case-control study among the Chinese Uygur population, involving 126 adult asthmatic patients and 126 healthy controls. The frequency of the ADAM33 T1 C allele among asthma patients was significantly higher compared to healthy controls (20.6 vs. 11.1%, P=0.003). The distribution of ADAM33 genotypes differed significantly between the two groups. The frequency of the T1 TC genotype was higher among patients compared to healthy controls [odds ratio (OR)=2.118, P=0.016] and the variant genotype, TC+CC, increased the risk of asthma (OR=2.244, P=0.005). Following adjustment for confounding factors, the ORs of TC and TC+CC for asthma were 2.317 and 2.522, respectively. There was a significant decrease in the forced expiratory volume (FEV₁) levels in patients with the TC genotype compared to the TT genotype of T1. Haplotype analysis revealed that the frequencies of Hap5 (CAC) and Hap6 (CAT) were significantly higher among asthmatic patients compared to healthy controls (P=0.024 and 0.016, respectively). The genotype and allele frequencies of SNP S+1 and F+1 were not statistically different between asthmatic patients and controls. In conclusion, the ADAM33 T1 SNP may affect susceptibility to asthma in the Chinese Uygur population.

HTR2A-1438A/G polymorphism influences the risk of schizophrenia but not bipolar disorder or major depressive disorder: a meta-analysis

The incidence of psychiatric disorders has been shown to have a strong genetic component, and we conducted this study to investigate whether the -1438A/G polymorphism of the HTR2A gene was associated with susceptibility to schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). Pooled odd ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using data obtained from a total 27 studies that investigated an association between the HTR2A -1438A/G polymorphism and SZ (15), BD (7), and MDD (4). We failed to observe an association between the HTR2A -1438A/G polymorphism and BD and MDD, and we found contrary results with regard to SZ. Our results showed that the -1438A/G polymorphism was a risk factor for SZ, especially in Caucasians (allele model: OR, 1.12; 95% CI, 1.05-1.20; I(2) = 17.3%; dominant model: OR, 1.14; 95% CI, 1.03-1.27; I(2) = 15.3%; recessive model: OR, 1.20; 95% CI, 1.06-1.37; I(2) = 0.0%; codominant model 1: OR, 1.16; 95% CI, 1.01-1.32; I(2) = 0.0%). We found that the association of the HTR2A -1438A/G polymorphism with SZ depends on the ethnic origin of the study population, and this genetic variant does not modify the susceptibility to BD or MDD. © 2013 Wiley Periodicals, Inc.

Methylenetetrahydrofolate reductase 677TT genotype might be associated with an increased lung cancer risk in Asians

BACKGROUND

The association between methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism and lung cancer risk has been studied in various populations with conflicting results. The aim of this study was to assess the association strength by a meta-analysis of published studies.

METHODS

We searched PubMed and Chinese Biomedical (CBM) databases for relevant literatures published by July 18, 2012. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the strength of the association.

RESULTS

A total of 20 studies comprising 11,653 cases and 12,032 controls were included in the final meta-analysis. Using the random effect model, we found that MTHFR 677TT variant genotype was associated with an increased lung cancer risk (OR=1.26, 95% CI=1.05-1.50, P=0.011 for TT vs. CC; OR=1.19, 95% CI=1.03-1.37, P<0.001 for TT vs. CC+CT; OR=1.11, 95% CI=1.02-1.22, P=0.017 for T allele vs. C allele). In the further stratified analyses, the increased lung cancer risk was found in Asian subjects (OR=1.31, 95% CI=1.01-1.71, P=0.045 for TT vs. CC; OR=1.17, 95% CI=1.00-1.38, P=0.048 for TT vs. CC+CT). There were no evidences for obvious publication bias in the overall meta-analysis and Asian subjects.

CONCLUSIONS

MTHFR 677TT genotype might increase the susceptibility of lung cancer, especially in Asians.

Transforming growth factor-beta1 in inflammatory airway disease: a key for understanding inflammation and remodeling

Airway diseases such as chronic rhinosinusitis, asthma, and chronic obstructive pulmonary disorder are characterized by inflammation and remodeling. Among inflammatory and extracellular matrix regulatory cytokines, transforming growth factor-beta (TGF-β) stands central, as it possesses both important immunomodulatory and fibrogenic activities, and should be considered a key for understanding inflammation and remodeling processes. This review will briefly summarize the recent findings on the role of TGF-β1, from the view points of inflammation and remodeling, and discuss the role of TGF-β in the upper and lower airway diseases. This may reveal new perspectives in the understanding of airway inflammation and remodeling processes and may open innovative treatment strategies for the regulation of TGF-β1.

Novel non-canonical TGF-β signaling networks: emerging roles in airway smooth muscle phenotype and function

The airway smooth muscle (ASM) plays an important role in the pathophysiology of asthma and chronic obstructive pulmonary disease (COPD). ASM cells express a wide range of receptors involved in contraction, growth, matrix protein production and the secretion of cytokines and chemokines. Transforming growth factor beta (TGF-β) is one of the major players in determining the structural and functional abnormalities of the ASM in asthma and COPD. It is increasingly evident that TGF-β functions as a master switch, controlling a network of intracellular and autocrine signaling loops that effect ASM phenotype and function. In this review, the various elements that participate in non-canonical TGF-β signaling, including MAPK, PI3K, WNT/β-catenin, and Ca(2+), are discussed, focusing on their effect on ASM phenotype and function. In addition, new aspects of ASM biology and their possible association with non-canonical TGF-β signaling will be discussed.

The rs11833579 and rs12425791 polymorphisms and risk of ischemic stroke in an Asian population: a meta-analysis

BACKGROUND

In 2009, a GWAS has confirmed that rs11833579 and rs12425791 near the NINJ2 gene could increase the stroke and ischemic stroke (IS) risk. Recently, several studies have been implemented to assess the relationship between the two SNPs and ischemic stroke risk in Asian. However, the results were poorly consistent. To study the association between the both polymorphisms and the risk of ischemic stroke, we performed a meta-analysis.

METHODS

We used odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the strength of association. The heterogeneity was checked by Q test and the inconsistency index (I(2)). Begg's test and Egger's test were used to assess the possible publication bias.

RESULTS

Our study included 6 articles, contained 9 independent case-control studies, involved a total of 9,142 cases and 10,652 controls about rs11833579, 10,165 cases and 11,592 controls about rs12425791. There was a significant association between rs12425791 and IS risk with dominant genetic model (OR=1.087, 95%CI=1.021-1.158, I(2)=34.6%, P=0.152), but not with recessive genetic model and allele A vs. allele G. For rs11833579, we failed to verify it relate with IS risk under allele A vs. allele G, dominant and recessive genetic model.

CONCLUSIONS

This meta-analysis suggest that rs12425791 is relative to ischemic stroke risk under dominant model in Asian population, but not for rs11833579.

The insertion/deletion (I/D) polymorphism in the Angiotensin-converting enzyme gene and cancer risk: a meta-analysis

Background

The insertion/deletion (I/D) polymorphism in the Angiotensin-converting enzyme (ACE) gene has been implicated in susceptibility to cancer, but a large number of studies have reported inconclusive results. The aim of this study is to assess the association between the I/D polymorphism in the ACE gene and cancer risk by meta-analysis.

Methods

A search was performed in Pubmed database, Embase database, Chinese Biomedical (CBM) database, China National Knowledge Infrastructure (CNKI) database and Weipu database, covering all studies until August 31, 2010. Statistical analysis was performed by using Revman4.2 and STATA 10.0.

Results

A total of 25 case-control studies comprising 3914 cancer patients and 11391 controls were identified. No significant association was found between the I/D polymorphism and over all cancer risks (OR = 0.88, 95%CI = 0.73-1.06, P = 0.17 for DD+DI vs. II). In the subgroup analysis by ethnicity, no significant association was found among Asians and Europeans for the comparison of DD+DI vs. II. In the subgroup analysis by cancer types, no significant associations were found among lung cancer, breast cancer, prostate cancer, colorectal cancer, gastric cancer for the comparison of DD+DI vs. II. Results from other comparative genetic models also indicated the lack of associations between this polymorphism and cancer risks.

Conclusions

This meta-analysis suggested that the ACE D/I polymorphism might not contribute to the risk of cancer.

The -1082A/G polymorphism in the Interleukin-10 gene and the risk of rheumatoid arthritis: a meta-analysis

A large number of studies have shown that the -1082A/G polymorphism (rs1800896) in the Interleukin-10 gene (IL-10) is implicated in the susceptibility to rheumatoid arthritis (RA). However, the results are inconsistent and inconclusive. The aim of this study is to analyze the association between the -1082A/G polymorphism in the IL-10 gene and the RA risk by meta-analysis. A total of 1480 cases and 1413 controls in 10 case-control studies were included in this meta-analysis. The results indicated that the G allele carriers (GG+GA) had a 25% decreased risk of RA, when compared with the homozygote AA (odds ratio (OR)=0.75, 95% confidence interval (CI): 0.59-0.93). In the analysis in Europeans, significant decreased risks were associated with the G allele carriers (OR=0.73 and 95% CI: 0.57-0.93 for GG+GA vs. AA). The results from this meta-analysis provide evidence for the association between the IL-10 -1082A/G polymorphism and the risk of RA. To further evaluate gene×gene and gene×environment interactions between the polymorphisms in the IL-10 gene and RA risk, more studies with large groups of patients are required.

The Arg194Trp polymorphism in the XRCC1 gene and cancer risk in Chinese Mainland population: a meta-analysis

The Arg194Trp polymorphism in the X-ray repair cross-complementing group 1 (XRCC1) gene has been proved to be in association with cancer risk in Chinese Mainland population, but a large number of studies have reported inconclusive results. A more comprehensive and precise estimation of the relationship is needed to clear the way towards future studies. Thus, we performed a meta-analysis to analysis these associations. A total of 34 case-control studies in 34 articles were included in this meta-analysis. The results showed that the 194Trp/Trp homozygote had a 31% increased risk of cancer than 194Trp/Arg and 194Arg/Arg genotypes, OR was 1.31 and 95%CI was 1.13 to 1.53. In the subgroup analysis by cancer sites, the Arg194Trp polymorphism was associated with increased risks of lung cancer (OR = 1.27 and 95%CI: 1.07-1.50 for Trp/Trp versus Arg/Arg + Arg/Trp) and esophageal cancer (OR = 1.68 and 95%CI: 1.33-2.13 for Trp/Trp versus Arg/Arg + Arg/Trp). This meta-analysis suggested that the Arg194Trp polymorphism of the XRCC1 gene is a cancer susceptible factor among Chinese Mainland population. More intensive and deeper studies are needed to further reveal the mechanism between Arg194Trp polymorphisms of XRCC1 gene and cancer risks in Chinese Mainland population.

Polymorphisms in the cytotoxic T-lymphocyte antigen 4 gene and cancer risk: a meta-analysis

BACKGROUND

Polymorphisms in the cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene have been implicated in susceptibility to cancer, but the many published studies have reported inconclusive results. The objective of the current study was to conduct a meta-analysis investigating the association between polymorphisms in the CTLA-4 gene and the risk of cancer.

METHODS

The PubMed and EMBASE databases were searched for all articles published up to September 19, 2010 that addressed cancer and polymorphisms, variants, or mutations of CTLA-4. A statistical analysis was performed using proprietary statistical software.

RESULTS

Three polymorphisms (+49 adenine/guanine [+49A/G], -318 cytosine/thymine [-318C/T], and the +6230G/A polymorphism [CT60]) in 48 case-control studies from 27 articles were analyzed. The results indicated that individuals who carried the +49 G allele (AG + GG) had a 16% decreased risk of cancer compared with homozygotes (+49AA; odds ratio [OR], 0.84; 95% confidence interval [CI], 0.74-0.95). However, there was no significant association between the risk of cancer and the -318C/T polymorphism or the CT60 polymorphism (-318C/T: OR, 1.23; 95% CI, 0.99-1.54 for TT + TC vs CC; CT60: OR, 1.02; 95% CI, 0.80-1.29 for AA + AG vs GG). In further stratified analyses for the +49A/G and -318C/T polymorphisms, the decreased risk of cancer remained in subgroups of Europeans, patients with breast cancer, and patients with lung cancer for the +49A/G polymorphism; whereas an increased risk of cancer was observed among Europeans for the -318C/T polymorphism.

CONCLUSIONS

Results from the current meta-analysis suggested that the +49A/G and -318C/T polymorphisms in CTLA-4 are risk factors for cancer. To further evaluate gene-gene and gene-environment interactions between CTLA-4 polymorphisms and the risk of cancer, more studies with larger groups of patients will be required.

The I/D polymorphism of angiotensin-converting enzyme gene and asthma risk: a meta-analysis

BACKGROUND

  The insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) gene has been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. The aim of this study is to investigate the association between the I/D polymorphism of ACE gene and asthma risk by meta-analysis.

METHODS

  We searched Medline (Ovid), Pubmed, CNKI, Wanfang, and Weipu database, covering all papers until March 12, 2010. Statistical analysis was performed by using the software revman 4.2 (The Cochrane Collaboration, http://www.cochrane.org) and stata 10.0 (StataCorp, College Station, TX, USA, http://www.stata.com).

RESULTS

  A total of 1946 cases and 2152 controls in 18 case-control studies were included in this meta-analysis. The results indicated that the DD homozygote carriers had a 59% increased risk of asthma, when compared with the homozygotes II and heterozygote DI [odds ratio (OR)=1.59, 95% confidence interval (CI): 1.16-2.18]. In the subgroup analysis by ethnicity, significant elevated risks were associated with DD homozygote carriers in Asians (OR=2.02 and 95% CI: 1.29-3.16 for DD vs DI+II) but not in Caucasians (OR=1.14 and 95% CI: 0.76-1.72 for DD vs DI+II). In the subgroup analysis by age, significant elevated risks were associated with DD homozygote carriers in children (OR=2.44 and 95% CI: 1.36-4.38 for DD vs II+DI) but not in adults (OR=1.54 and 95% CI: 0.94-2.51 for DD vs II+DI).

CONCLUSIONS

  This meta-analysis suggested that the I/D polymorphism of ACE gene would be a risk factor of asthma. To further evaluate gene-to-gene and gene-to-environment interactions between polymorphisms of ACE gene and asthma risk, more studies with large groups of patients are required.

The -1082G/A polymorphism in IL-10 gene is associated with risk of Alzheimer's disease: a meta-analysis

BACKGROUND

The -1082G/A polymorphism in IL-10 gene has been extensively investigated for association to Alzheimer's disease (AD), however, results of different studies have been inconsistent. The objective of this study is to assess the relationship of IL-10 -1082G/A polymorphism and AD risk by using meta-analysis.

METHODS

All eligible case-control studies were searched in Pubmed and Embase. Odds ratios (OR) with the 95% confidence intervals (CI) were used to assess the association.

RESULTS

A total of 2158 cases and 2088 controls in 12 case-control studies were included. The results indicated that the A allele carriers (AA+AG) had a 27% increased risk of AD, when compared with the homozygote GG (OR=1.27, 95%CI=1.02-1.58 for AA+AG vs. GG). In the subgroup analysis by ethnicity, significant elevated risks were associated with A allele carriers in Europeans (OR=1.27 and 95%CI=1.01-1.59 for AA+AG vs. GG), but not in Asians (OR=1.37 and 95%CI=0.32-5.88 for AA+AG vs. GG).

CONCLUSIONS

This meta-analysis suggested that the -1082G/A polymorphism of IL-10 gene would be a risk factor for AD. To further evaluate gene-to-gene and gene-to-environmental interactions between polymorphisms of IL-10 gene and AD risk, more studies with large groups of patients are required.

Aquaporin 5 polymorphisms and rate of lung function decline in chronic obstructive pulmonary disease

RATIONALE

Aquaporin-5 (AQP5) can cause mucus overproduction and lower lung function. Genetic variants in the AQP5 gene might be associated with rate of lung function decline in chronic obstructive pulmonary disease (COPD).

METHODS

Five single nucleotide polymorphisms (SNPs) in AQP5 were genotyped in 429 European American individuals with COPD randomly selected from the NHLBI Lung Health Study. Mean annual decline in FEV(1) % predicted, assessed over five years, was calculated as a linear regression slope, adjusting for potential covariates and stratified by smoking status. Constructs containing the wildtype allele and risk allele of the coding SNP N228K were generated using site-directed mutagenesis, and transfected into HBE-16 (human bronchial epithelial cell line). AQP5 abundance and localization were assessed by immunoblots and confocal immunofluorescence under control, shear stress and cigarette smoke extract (CSE 10%) exposed conditions to test for differential expression or localization.

RESULTS

Among continuous smokers, three of the five SNPs tested showed significant associations (0.02>P>0.004) with rate of lung function decline; no associations were observed among the group of intermittent or former smokers. Haplotype tests revealed multiple association signals (0.012>P>0.0008) consistent with the single-SNP results. In HBE16 cells, shear stress and CSE led to a decrease in AQP5 abundance in the wild-type, but not in the N228K AQP5 plasmid.

CONCLUSIONS

Polymorphisms in AQP5 were associated with rate of lung function decline in continuous smokers with COPD. A missense mutation modulates AQP-5 expression in response to cigarette smoke extract and shear stress. These results suggest that AQP5 may be an important candidate gene for COPD.

Asthma susceptible genes in Chinese population: a meta-analysis

BACKGROUND

Published data regarding the associations between genetic variants and asthma risk in Chinese population were inconclusive. The aim of this study was to investigate asthma susceptible genes in Chinese population.

METHODS

The authors conducted 18 meta-analyzes for 18 polymorphisms in 13 genes from eighty-two publications.

RESULTS

Seven polymorphisms were found being associated with risk of asthma, namely: A Disintegrin and Metalloprotease 33 (ADAM33) T1-C/T (odds ratio [OR] = 6.07, 95% confidence interval [CI]: 2.69-13.73), Angiotensin-Converting Enzyme (ACE) D/I (OR = 3.85, 95%CI: 2.49-5.94), High-affinity IgE receptor β chain (FcεRIβ) -6843G/A (OR = 1.49, 95%CI: 1.01-2.22), Interleukin 13(IL-13) -1923C/T (OR = 2.99, 95%CI: 2.12-4.24), IL-13 -2044A/G (OR = 1.49, 95%CI: 1.07-2.08), Regulated upon Activation, Normal T cell Expressed and Secreted (RANTES) -28C/G (OR = 1.64, 95%CI: 1.09-2.46), Tumor Necrosis Factor-α (TNF-α) -308G/A(OR = 1.42, 95%CI: 1.09, 1.85). After subgroup analysis by age, the ACE D/I, β2-Adrenergic Receptor (β2-AR) -79G/C, TNF-α -308G/A, Interleukin 4 receptor(IL-4R) -1902G/A and IL-13 -1923C/T polymorphisms were found significantly associated with asthma risk in Chinese children. In addition, the ACE D/I, FcεRIβ -6843G/A, TNF-α -308G/A, IL-13 -1923C/T and IL-13 -2044A/G polymorphisms were associated with asthma risk in Chinese adults.

CONCLUSION

ADAM33, FcεRIβ, RANTES, TNF-α, ACE, β2-AR, IL-4R and IL-13 genes could be proposed as asthma susceptible genes in Chinese population. Given the limited number of studies, more data are required to validate these associations.