TGFB1 promoter polymorphism C-509T and pathophysiology of asthma

The Role of Transforming Growth Factor-β (TGF-β) in Asthma and Chronic Obstructive Pulmonary Disease (COPD)

Asthma and chronic obstructive pulmonary disease (COPD) represent chronic inflammatory respiratory disorders that, despite having distinct pathophysiological underpinnings, both feature airflow obstruction and respiratory symptoms. A critical component in the pathogenesis of each condition is the transforming growth factor-β (TGF-β), a multifunctional cytokine that exerts varying influences across these diseases. In asthma, TGF-β is significantly involved in airway remodeling, a key aspect marked by subepithelial fibrosis, hypertrophy of the smooth muscle, enhanced mucus production, and suppression of emphysema development. The cytokine facilitates collagen deposition and the proliferation of fibroblasts, which are crucial in the structural modifications within the airways. In contrast, the role of TGF-β in COPD is more ambiguous. It initially acts as a protective agent, fostering tissue repair and curbing inflammation. However, prolonged exposure to environmental factors such as cigarette smoke causes TGF-β signaling malfunction. Such dysregulation leads to abnormal tissue remodeling, marked by excessive collagen deposition, enlargement of airspaces, and, thus, accelerated development of emphysema. Additionally, TGF-β facilitates the epithelial-to-mesenchymal transition (EMT), a process contributing to the phenotypic alterations observed in COPD. A thorough comprehension of the multifaceted role of TGF-β in asthma and COPD is imperative for elaborating precise therapeutic interventions. We review several promising approaches that alter TGF-β signaling. Nevertheless, additional studies are essential to delineate further the specific mechanisms of TGF-β dysregulation and its potential therapeutic impacts in these chronic respiratory diseases.

Genotypic and allelic distribution of IFN-γ +874T/A and TGF-β1 -509C/T single-nucleotide polymorphisms in human immunodeficiency virus-infected Thais

Advances in antiretroviral therapy (ART) have led to a decrease of acquired immunodeficiency syndrome (AIDS)-related mortality, and an increase of non-AIDS illnesses in people living with HIV (PLWH). Risks for HIV-related chronic inflammation leading to non-AIDS illnesses in PLWH have been increasingly clarified including immunogenetic factors. This study aimed to examine distribution of genotypic and allelic frequencies of the well-characterized interferon-γ (IFN-γ) +874T/A and transforming growth factor-β1 (TGF-β1) -509C/T single nucleotide polymorphisms (SNPs) in Thai PLWH. The cross-sectional study was conducted in 191 Thai HIV patients. Most patients were under ART (74.3%) and maintained a relatively high median of CD4⁺  cell count (364.5 [5-1601] cells/μl). The frequencies of IFN-γ +874T/A  SNP genotypes were 9.0% AA, 38.3% AT, and 52.7% TT and those of the SNP alleles were 28.1% A and 71.9% T. The rates of TGF-β1-509C/T SNP genotypes were 15.7% CC, 44.0% CT, and 40.3% TT and those of the SNP alleles were 37.7% C and 62.3% T. The more frequent TT genotypes and T allele of the IFN-γ +874T/A SNP, and relatively more prevalent TT and CT genotypes and T allele of TGF-β1 -509C/T SNP were potentially associated with disease progression to non-AIDS complication in Thai PLWH and required further investigation. This study provides the immunogenetic data potentially supporting mechanisms for chronic immune activation in PLWH under long-term suppressive ART.

Polymorphism -509C/T in TGFB1 Promoter Is Associated With Increased Risk and Severity of Persistent Allergic Rhinitis in a Chinese Population

BACKGROUND

Polymorphism -509C/T in the promoter of transforming growth factor beta1 (TGFB1) gene is implicated in the pathogenesis of asthma. This polymorphism might also act to regulate the development of allergic rhinitis (AR).

OBJECTIVES

To investigate whether -509C/T is associated with AR susceptibility and severity in a Han Chinese population.

METHODS

The study enrolled 263 patients with persistent AR and 249 healthy controls. AR patients were classified as mild or moderate/severe AR groups according to the Allergic Rhinitis and its Impact on Asthma classification. TGFB1 gene polymorphism -509C/T was genotyped with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum total Immunoglobulin E (IgE) and specific IgE levels were determined using an ImmunoCAP.

RESULTS

Significant difference was found in the allele frequency of TGFB1 -509C/T between AR patients and healthy controls (P = .027) but not in the genotype frequency (P =.051). However, the genotype frequency of TGFB1 -509C/T showed significant difference between the mild AR group, the moderate/severe AR group, and the control group (P = .012); between the moderate/severe AR group and the control group (P =.036); between the mild AR group and the moderate/severe AR group (P = .038); but not between the mild AR group and the control group (P =.075).

CONCLUSION

TGFB1 promoter polymorphism -509C/T may be associated with the susceptibility and the severity of persistent AR of Han Chinese, but the functional relationship still needs clarification.

Influence of the Polymorphism C-509T in the TGFB1 Gene Promoter on the Response to Montelukast

Transforming growth factor beta 1 (TGFB1) is a multifunctional cytokine with a key role in asthma airway inflammation and remodeling. Since elevated levels of this cytokine in airways might be associated with response to asthma therapy, the aim of this study was to investigate whether the presence of the polymorphism C-509T in the promoter of the TGFB1 gene is associated with response to montelukast. A group of 102 asthmatic patients was genotyped for the presence of the C-509T polymorphism by DNA sequencing and subjected to induced sputum sampling. Cells from sputum samples and BEAS 2B cells were treated with montelukast and endogenous TGFB1 expression was measured by quantitative real-time polymerase chain reaction. The promoter activity was analyzed by luciferase assays in BEAS 2B cells transfected with constructs carrying variants -509C and -509T of the TGFB1 gene promoter. After treatment with montelukast, the decrease in TGFB1 gene expression was greater for the -509TT genotype (58.9%) than for the -509CC and -509CT genotypes (49.6% and 31.8%, respectively) (P = 0.071). In BEAS 2B cells, expression of endogenous TGFB1 was reduced by about 27% after montelukast treatment, while luciferase activity of both promoter variants was increased after montelukast treatment (-509C allele: 48.3%, P = 0.060; and -509T allele: 100.5%, P = 0.062). A more intensive response was registered in the promoter containing the -509T allele, which had 135% higher activity than the -509C variant (P = 0.035). This study showed that the presence of the -509T allele in the TGFB1 promoter might modulate effects of montelukast on TGFB1 gene expression, but future studies are necessary, taking into consideration other genetic and nongenetic factors. It is of potential importance for clinical management of asthma to clarify the influence of the C-509T polymorphism on the response to treatment with montelukast.

Polymorphisms of TGFB1, TLE4 and MUC22 are associated with childhood asthma in Chinese population

OBJECTIVE

To investigate whether the genetic variants of TGFB1, TLE4, MUC22 and IKZF3 are associated with the development of asthma in Chinese children.

METHODS

572 adolescent asthma patients and 590 age-matched healthy controls were included in this study. A total of four SNPs were genotyped, including rs2241715 of TGFB1, rs2378383 of TLE4, rs2523924 of MUC22, and rs907092 of IKZF3. Allele frequencies of the patients and the control group were compared by the Chi-square test. The Student t test was used to analyse the relationship between genotypes and clinical feature of the patients.

RESULTS

Patients were found to have significantly different frequencies of allele A of rs2241715, allele G of rs2378383 and allele A of rs2523924 as compared with the controls (40.4% vs. 45.9%, p=0.01 for rs2241715; 17.2% vs. 13.4%, p=0.01 for rs2378383; 15.3% vs. 11.9%, p=0.02 for rs2523924). For patients with severe asthma, those with genotype AA/AG of rs2241715 had remarkably higher FEV1% as compared with those with genotype GG (59.1±4.3% vs. 55.4±3.7%, p<0.001). Moreover, those with genotype GG/GA of rs2378383 had remarkably lower FEV1% as compared with those with genotype AA (54.6±2.9% vs. 58.6±4.1%, p<0.001).

CONCLUSIONS

Genes TGFB1, TLE4 and MUC22 are associated with the risk of childhood asthma in Chinese population. Our results associating TGFB1 and TLE4 with clinical features of asthma suggest potential application of these parameters in the management of asthma children.

Phenotypic and genetic aspects of epithelial barrier function in asthmatic patients

The bronchial epithelium is continuously exposed to a multitude of noxious challenges in inhaled air. Cellular contact with most damaging agents is reduced by the action of the mucociliary apparatus and by formation of a physical barrier that controls passage of ions and macromolecules. In conjunction with these defensive barrier functions, immunomodulatory cross-talk between the bronchial epithelium and tissue-resident immune cells controls the tissue microenvironment and barrier homeostasis. This is achieved by expression of an array of sensors that detect a wide variety of viral, bacterial, and nonmicrobial (toxins and irritants) agents, resulting in production of many different soluble and cell-surface molecules that signal to cells of the immune system. The ability of the bronchial epithelium to control the balance of inhibitory and activating signals is essential for orchestrating appropriate inflammatory and immune responses and for temporally modulating these responses to limit tissue injury and control the resolution of inflammation during tissue repair. In asthmatic patients abnormalities in many aspects of epithelial barrier function have been identified. We postulate that such abnormalities play a causal role in immune dysregulation in the airways by translating gene-environment interactions that underpin disease pathogenesis and exacerbation.

TGF-β1 Suppresses IL-33-Induced Mast Cell Function

TGF-β1 is involved in many pathological conditions, including autoimmune disorders, cancer, and cardiovascular and allergic diseases. We have previously found that TGF-β1 can suppress IgE-mediated mast cell activation of human and mouse mast cells. IL-33 is a member of the IL-1 family capable of inducing mast cell responses and enhancing IgE-mediated activation. In this study, we investigated the effects of TGF-β on IL-33-mediated mast cell activation. Bone marrow-derived mast cells cultured in TGF-β1, β2, or β3 showed reduced IL-33-mediated production of TNF, IL-6, IL-13, and MCP-1 in a concentration-dependent manner. TGF-β1 inhibited IL-33-mediated Akt and ERK phosphorylation as well as NF-κB- and AP-1-mediated transcription. These effects were functionally important, as TGF-β1 injection suppressed IL-33-induced systemic cytokines in vivo and inhibited IL-33-mediated cytokine release from human mast cells. TGF-β1 also suppressed the combined effects of IL-33 and IgE-mediated activation on mouse and human mast cells. The role of IL-33 in the pathogenesis of allergic diseases is incompletely understood. These findings, consistent with our previously reported effects of TGF-β1 on IgE-mediated activation, demonstrate that TGF-β1 can provide broad inhibitory signals to activated mast cells.

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.

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.

Genetics of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a complex genetic disorder characterized by eosinophilic inflammation within the esophagus. Multiple epidemiological studies estimate the prevalence of EoE is 4 in 10,000, with a higher disease prevalence in individuals of European ancestry and in males, highlighting a genetic etiology of the disease. EoE has often been noted to occur in multiple family members, particularly siblings, in a non-Mendelian pattern, indicating the heritable component of EoE is likely complex in nature. Although EoE is a newly diagnosed disorder involving a complex polygenic etiology, much progress has been made towards identifying the molecular pathways contributing to the disease pathogenesis and the genetic variants associated with disease susceptibility using a variety of approaches (genome-wide and candidate gene) as well as study designs (case-control and family-based cohorts). Here, we discuss the major scientific findings that have shaped the current molecular and genetic landscape of EoE as well as the major obstacles in the discovery of disease causal variants in complex disorders.

Lack of Association of Tumor Necrosis Factor-α G-308A and Transforming Growth Factor-β1 C-509T Polymorphisms in Patients with Deep Neck Space Infections

Deep neck space infections are defined as infections that spread along the fascial planes and spaces of the head and neck. Even in the era of antibiotics, these infections can and have been potentially life-threatening conditions. The role of single nucleotide polymorphisms (SNPs) of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) genes in deep neck infections has not been studied. Thus, the aim of this study was to investigate the distribution of the TNF-α G-308A and TGF-β1 C-509T polymorphisms in patients suffering from infections of deep neck spaces and to determine the correlation of these polymorphisms with the values of inflammation markers [C-reactive protein (CRP) and white blood cell (WBC) count]. A total of 41 patients with infections of deep neck spaces and 44 healthy controls were screened for TNF-α G-308A and TGF-β1 C-509T polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The distribution of the TNF-α G-308A genotype in patients did not reveal statistically significant correlation compared to con-trols (p = 0.483, χ(2) = 0.491) as well as the distribution of the TGF-β1 C-509T genotypes (p = 0.644, χ(2) = 0.725). The distribution of TNF-α -308 and TGF-β1 -509 alleles was not significantly different in patients compared to controls. Moreover, CRP levels and WBC counts were not associated with TNF-α G-308A and TGF-β1 C-509T promoter polymorphisms in patients with deep neck infections. In conclusion, our study suggests that the TNF-α G-308A and TGF-β1 C-509T polymorphisms are not associated with infections of deep neck spaces.

Mechanical aspects of lung fibrosis: a spotlight on the myofibroblast

Contractile myofibroblasts are responsible for the irreversible alterations of the lung parenchyma that hallmark pulmonary fibrosis. In response to lung injury, a variety of different precursor cells can become activated to develop myofibroblast features, most notably formation of stress fibers and expression of α-smooth muscle actin. Starting as an acute and beneficial repair process, myofibroblast secretion of collagen and contraction frequently becomes excessive and persists. The result is accumulation of stiff scar tissue that obstructs and ultimately destroys lung function. In addition to being a consequence of myofibroblast activities, the stiffened tissue is also a major promoter of the myofibroblast. The mechanical properties of scarred lung and fibrotic foci promote myofibroblast contraction and differentiation. One essential element in this detrimental feed-forward loop is the mechanical activation of the profibrotic growth factor transforming growth factor-β1 from stores in the extracellular matrix. Interfering with myofibroblast contraction and integrin-mediated force transmission to latent transforming growth factor-β1 and matrix proteins are here presented as possible therapeutic strategies to halt fibrosis.

Asthma phenotypes in adults and clinical implications

It is becoming increasingly recognized that asthma is a heterogeneous disease, whether based on clinical factors, including the patient's age at diagnosis, symptom spectrum and treatment response, triggering factors, or the level and type of inflammation. Attempts to analyze the importance of these characteristics to the clinical presentation of asthma have led to the appreciation of numerous separate and overlapping asthma phenotypes. However, these approaches are 'biased' and based on the clinician/scientist's own experience. Recently, unbiased approaches have also been attempted using both molecular and statistical tools. Early results from these approaches have supported and expanded on the clinician's concepts. However, until specific biologic markers are identified for any of these proposed phenotypes, the definitive nature of any phenotype will remain speculative.

Cytokine gene polymorphism and asthma susceptibility, progress and control level

Asthma is a multifactor inflammatory disorder, and its management requires understanding of its various pathogenesis and control mechanisms. Cytokines and other inflammatory mediators are important factors in asthma pathophysiology. In this study, we evaluated the role of cytokine polymorphisms in the asthma susceptibility, progress, control, and lung functions. IL-4-C590T polymorphism by PCR-RFLP method, IFN-γ T+874A, TNF-α-A308G, IL-6 G-174C and TGF-β T+869C variants by ARMS-PCR method and IgE serum level by ELISA technique were determined in 81 asthmatic patients and 124 normal subjects. Asthma diagnosis, treatment and control levels were considered using standard schemes and criteria. TNF-α-308GA genotype was more frequent in asthmatics (P = 0.025, OR 3.352), and polymorphisms between different asthma control levels (P > 0.05) were not different. IFN-γ+874AT genotype had a positive correlation with the familial history of asthma (P = 0.034, OR 2.688). IL-6-174C allele (P = 0.045), TNF-α-308GG genotype (P = 0.002) and TNF-α-308G allele (P = 0.004) showed reduced values, and TNF-α-308GA genotype (P = 0.002) increased FEF25-75 value in asthmatics. IFN-γ+874AA genotype caused a decrease in FVC factor (P = 0.045). This study showed that TNF-α-308GA is a risk factor for asthma, but cytokine gene variants do not affect asthma control and IgE serum levels. Variants producing lower levels of IL-6, TNF-α and IFN-γ are associated with reduced pulmonary capacities. To achieve an appropriate schema for asthma management, further studies with consideration of different aspects in a larger group of patients would be more elucidative.

Genetic dissection of eosinophilic esophagitis provides insight into disease pathogenesis and treatment strategies

Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder of the esophagus that is compounded by both genetic predisposition and aberrant responses to environmental antigens, particularly those that are food derived. Data have indicated a unique transcriptional response in vivo that defines EoE and that appears to be partially attributable to the T(H)2 cytokine IL-13. Moreover, a number of genetic risk variants in proinflammatory and epithelial cell genes associate with EoE susceptibility, demonstrating novel heritable mechanisms that contribute to disease risk. Here we discuss recent advances in our understanding of the intrinsic (genetic) and extrinsic (environmental) components that illustrate the complex nature of EoE.

Oral viscous budesonide is effective in children with eosinophilic esophagitis in a randomized, placebo-controlled trial

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is caused by immunologic reactions to ingested/inhaled allergens. The diagnosis is considered if >or=15 eosinophils per high-powered field (eos/hpf) are detected in mucosal biopsies. Placebo-controlled studies have not been conducted to evaluate the safety and efficacy of oral viscous budesonide (OVB).

METHODS

Children with EoE were randomly assigned to groups that were given OVB (n=15) or placebo (n=9). Patients<5 feet and >or=5 feet tall received 1 mg and 2 mg OVB daily, respectively. All patients received lansoprazole. Duration of treatment was 3 months, followed by repeat endoscopy and biopsies. Patients were classified as responders if their peak eosinophil counts were <or=6 eos/hpf, partial responders were 7-19 eos/hpf, and nonresponders were >or=20 eos/hpf. Baseline and post-treatment symptoms and endoscopic and histologic features were scored.

RESULTS

Thirteen (86.7%) children given OVB (P<.0001) and none who received placebo (P=.3) were classified as responders. Mean pre-/post-treatment peak eosinophil counts were 66.7 and 4.8 eos/hpf, respectively, in the group given OVB (P<.0001); they were 83.9 and 65.6 eos/hpf, respectively, in the group given placebo (P=.3). In the group given OVB, there were significant reductions from baseline values in proximal (P=.002), mid (P=.0003), and distal (P=.001) esophageal eosinophilia. After OVB therapy, compared with baseline, the mean symptom (P=.0007), endoscopy (P=.0005), and histology scores improved (P=.0035) significantly.

CONCLUSIONS

OVB is an effective treatment of pan-esophageal disease in children with EoE. OVB improves symptoms and endoscopic and histologic features. Proton pump inhibitor single therapy did not significantly improve esophageal eosinophilia or symptoms of EoE.

Association of COPD candidate genes with computed tomography emphysema and airway phenotypes in severe COPD

The principal determining factors influencing the development of the airway disease and emphysema components of chronic obstructive pulmonary disease (COPD) have not been clearly defined. Genetic variability in COPD patients might influence the varying degrees of involvement of airway disease and emphysema. Therefore, we investigated the genetic association of single nucleotide polymorphisms (SNPs) in COPD candidate genes for association with emphysema severity and airway wall thickness phenotypes. Polymorphisms in six candidate genes were analysed in 379 subjects of the National Emphysema Treatment Trial (NETT) Genetics Ancillary Study with quantitative chest computed tomography (CT) data. Genetic association with per cent of lung area below -950 HU (LAA950), airway wall thickness, and derived square root wall area (SRWA) of 10-mm internal perimeter airways were investigated. Three SNPs in EPHX1, five SNPs in SERPINE2 and one SNP in GSTP1 were significantly associated with LAA950. Five SNPs in TGFB1, two SNPs in EPHX1, one SNP in SERPINE2 and two SNPs in ADRB2 were associated with airway wall phenotypes in NETT. In conclusion, several COPD candidate genes showed evidence for association with airway wall thickness and emphysema severity using CT in a severe COPD population. Further investigation will be required to replicate these genetic associations for emphysema and airway wall phenotypes.

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

BACKGROUND AND OBJECTIVE

Polymorphisms in the transforming growth factor-beta1 (TGF-beta1) gene have been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. A meta-analysis was performed to investigate the association between polymorphisms in the TGF-beta1 gene and asthma susceptibility.

METHODS

Searches were performed of Medline (Ovid), PubMed, the Chinese Biological Medicine Database (CBM), the Chinese Journals Full-text Database (CNKI), the Cochrane Library Database and the Web of Science, covering all papers published up to 30 April 2009. Statistical analysis was performed using Revman4.2.8 and STATA10.0 software.

RESULTS

Two polymorphisms (-509C/T and 915G/C(G25C)) were investigated in 14 studies, involving 2979 asthma patients and 4941 control subjects. The results showed that individuals carrying the -509T allele (TT+TC) had a 36% increased risk of asthma, when compared with homozygotes (-509CC) (OR 1.36, 95% CI: 1.12-1.65). However, there was no significant association with risk of asthma in carriers of the 915C allele (GC+CC) compared with 915GG homozygotes (OR 1.05, 95% CI: 0.65-1.70). In a subgroup analysis by ethnicity, the risk of asthma associated with the -509T allele was significantly elevated among Asians (OR 1.50, 95% CI: 1.04-2.17) but not Caucasians (OR 1.16, 95% CI: 1.00-1.36). In a subgroup analysis by age, the -509T allele was associated with a significantly elevated risk of asthma among adults (OR 1.45, 95% CI: 1.09-1.92) but not children (OR 1.19, 95% CI: 0.96-1.46).

CONCLUSIONS

This meta-analysis suggested that the -509C/T polymorphism in the TGF-beta1 gene may be a risk factor for asthma. To further evaluate gene-gene and gene-environment interactions between polymorphisms in the TGF-beta1 gene and asthma susceptibility, more studies involving thousands of patients are required.

Fibrogenic reactions in lung disease

Fibrogenic lung reactions occur as a common phenotype shared among disorders of heterogeneous etiologies. Even with a common etiology, the extent and pattern of fibrosis vary greatly among individuals, even within families, suggesting complex gene-environment interactions. The search for mechanisms shared among all fibrotic lung diseases would represent a major advance in the identification of therapeutic targets that could have a broad impact on lung health. Although it is difficult to grasp all of the complexities of the varied cell types and cytokine networks involved in lung fibrogenic responses, and to predict the biologic responses to the overexpression or deficiency of individual cytokines, a large body of evidence converges on a single common theme: the central importance of the transforming growth factor beta (TGF-beta) pathway. Therapies that act upstream or downstream of TGF-beta activation have the therapeutic potential to treat all fibrogenic responses in the lung.

Resolution of remodeling in eosinophilic esophagitis correlates with epithelial response to topical corticosteroids

BACKGROUND

Esophageal remodeling occurs in eosinophilic esophagitis (EE) patients but whether the components of remodeling in the subepithelium are reversible by administration of topical oral corticosteroids is unknown.

METHODS

We quantitated the degree of lamina propria remodeling in esophageal biopsies obtained before and after at least 3 months of therapy with budesonide in 16 pediatric EE subjects. In addition, we investigated whether corticosteroid therapy modulated vascular activation (expression of VCAM-1; level of interstitial edema), TGFbeta(1) activation (levels of TGFbeta(1), phosphorylated Smad2/3), and performed a pilot analysis of a polymorphism in the TGFbeta(1) promoter in relation to EE subjects who had reduced remodeling with budesonide therapy.

RESULTS

EE subjects were stratified based on the presence (n = 9) or absence (n = 7) of decreased epithelial eosinophilia following budesonide. Patients with residual eosinophil counts of <or=7 eosinophils per high power field in the epithelial space (responders) demonstrated significantly reduced esophageal remodeling with decreased fibrosis, TGFbeta(1) and pSmad2/3 positive cells, and decreased vascular activation in association with budesonide therapy. Responders were more likely to have a CC genotype at the -509 position in the TGFbeta(1) promoter.

CONCLUSIONS

Reductions in epithelial eosinophils following budesonide therapy were associated with significantly reduced esophageal remodeling.

Association of five single nucleotide polymorphism loci with asthma in children of Chinese Han nationality

BACKGROUND

Increasing research is available verifying that asthma is a familial and hereditary disorder of a complex of factors and genes. Objective. To investigate the single and combined associations of five single nucleotide polymorphism loci in three genes with the development of asthma in children of Chinese Han Nationality.

METHODS

A total of 192 children with asthma and an equal number of control subjects were recruited in this study. Asthma was diagnosed in accordance with American Thoracic Society criteria. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the genotypes of the single nucleotide polymorphism loci.

RESULTS

No statistic differences (p > 0.05) were found between experimental and control group in genotype distribution among three loci (NOS1 C5266T, TGF-beta1 L10P, and TGF-beta1 R25P). However, a significant diversity was observed among IL4-RA Q551R (p = 0.004) and TGF-beta1 C-509T (p = 0.000). Furthermore, the frequency of IL4-RA Q551R A/G and TGF-beta1 C-509T C/T in the asthma group were significantly higher than those in the control group (OR = 1.91, P = 0.002; OR = 2.90, P = 0.000, respectively). The carriers of both IL4-RA Q551R A/G and TGF-beta1 C-509T C/T did not have a more significant risk of having asthma than those who covered either.

CONCLUSION

The three loci (NOS1 C5266T, TGF-beta1 L10P and TGF-beta1 R25P) have little contribution to the development of childhood asthma in Chinese Han Nationality. IL4-RA Q551R and TGF-beta1 C-509T are single nucleotide polymorphism loci with significant association to childhood asthma, but they do not have synergistic effects.

TGF-beta can leave you breathless

Transforming growth factor-beta (TGF-beta), a ubiquitous and multifunctional cytokine, is central to the evolution and modulation of host defense. Early on, TGF-beta was recognized for its chemotactic and pro-inflammatory properties, but then identification of its powerful suppressive activities focused attention on dissecting its mechanisms of immune inhibition. Just as quickly as TGF-beta-mediated regulation of a population of CD4(+)CD25(+)Foxp3(+) regulatory T cells became the rage, a surprising finding that TGF-beta was the impetus behind a subset of pro-inflammatory T helper (Th)17 cells brought back a re-emphasis on its broader ability to dictate inflammatory events. Emerging evidence indicates that much remains to be discovered regarding the complex and intertwined roles of TGF-beta in inflammation, T cell lineage commitment, antibody generation, immune suppression, and tolerance. While it may appear that TGF-beta has multiple, ill-defined, contradictory and overlapping modes of activity that are impossible to unravel, the current excitement for dissecting how TGF-beta controls immunity defines a challenge worthy of pursuit. The lung is particularly vulnerable to the influences of TGF-beta, which is produced by its immune and non-immune cell populations. In its absence, lung pathology becomes lethal, whereas TGF-beta overproduction also has untoward consequences, potentially leaving one breathless, and underscoring the paradoxical, but essential contribution of TGF-beta to tissue and immune homeostasis.

Age-related changes of transforming growth factor beta1 in Japanese children

BACKGROUND

Transforming growth factor beta1 (TGF beta 1) is an important factor in immunomodulation. The expression of TGF beta 1 has been shown to be influenced by the C-509T polymorphism in the TGF beta 1 gene. We investigated age-related changes of plasma TGF beta 1 levels in a birth-cohort study. In addition, the genotypes of the C-509T polymorphism were investigated in allergic and non-allergic subjects.

METHODS

Sixty-four neonates who met the following criteria were enrolled in this cohort study: 1) full-term vaginally delivery; 2) underwent DNA polymorphism analysis; and 3) questionnaire forms were filled out by parents at 0, 6 and 14 months of age. The umbilical cord blood at 0 months and peripheral blood at 6, and 14 months were collected. Plasma TGF beta1 levels were measured at 0, 6 and 14 months of age. Genomic DNA was extracted from their umbilical cord blood. The genotype of the subjects was examined for the presence of C-509T.

RESULTS

The plasma TGF beta 1 level at 6 months was the highest of the 3 measurements (at 0, 6, and 14 months of age). The TGF beta 1 levels at 14 months in allergic subjects were significantly higher than those in non-allergic subjects (p = 0.03). All subjects with bronchial asthma (n = 3) had the TT genotype of the C-509T polymorphism.

CONCLUSIONS

The plasma TGF beta 1 levels change with age. In addition, TGF beta 1 may play a role in the pathogenesis of bronchial asthma.

Matrix metalloproteinase-1 polymorphism is associated with persistent airway obstruction in asthma in the Taiwanese population

BACKGROUND AND OBJECTIVE

Overexpression of matrix metalloproteinase (MMP)-1 has been demonstrated in asthma, and MMP polymorphisms are known to enhance disease susceptibility. We investigated whether MMP-1 polymorphism is associated with persistent airway obstruction in asthma in the Taiwanese population.

METHODS

A total of 131 unrelated Taiwanese subjects were enrolled, age-matched, and divided as follows: (1) those who had asthma with persistent airway obstruction with forced expiratory volume in 1 second (FEV(1)) and FEV(1)/forced vital capacity (FVC) values less than 75% predicted (n = 41); (2) those with asthma without airway obstruction with FEV(1) and FEV(1)/FVC values > or = 75% predicted (n = 47); and (3) normal control subjects (n = 43). All were genotyped for the 1G/2G polymorphism of MMP-1 promoter (-1607 bp).

RESULTS

1G genotypes of MMP-1 containing at least one 1G allele were found in asthmatic patients with persistent airway obstruction (OR = 3.696, 95% CI: 1.489-9.173, p = 0.027), but not in asthmatic patients without airway obstruction (OR = 2.065, 95% CI: 0.890-4.790, p = 0.091) when compared with homozygous 2G (2G/2G). The heterozygous 1G genotype (1G/2G) was more associated with persistent airway obstruction than homozygous 2G (2G/2G) (OR: 4.727, 95% CI: 1.759-12.703, p = 0.012). The adjusted risk estimate of 1G genotypes for asthmatics with persistent airway obstruction was 4.416 (95% CI: 1.651-11.812, p = 0.003).

CONCLUSION

1G genotypes of MMP-1 polymorphism are associated with asthma with persistent airway obstruction, and the heterozygous 1G genotype (1G/2G) poses the most susceptibility to persistent airway obstruction in asthma.

Advances in pediatric asthma in 2008: where do we go now?

This year's summary focuses on recent advances in pediatric asthma as reported in Journal publications in 2008. New National Asthma Education and Prevention Program asthma guidelines were released in 2007 with a special emphasis on asthma control. Attention was redirected to methods that could reduce impairment, specifically symptom control, and minimize risk, including exacerbations. Journal theme issues in 2008 focused on several relevant asthma topics including asthma exacerbations, exercise-induced bronchospasm, asthma and obesity, and occupational asthma. This review highlights Journal articles and related articles that reinforce principles of the guidelines and also direct us to new information that will advance asthma care for children. A major step forward will be finding ways to implement the asthma guidelines.

Polymorphism of the TGFB1 gene is not associated with bronchial allergic asthma in a Polish population

Allergic asthma is a complex genetic disorder that involves interactions between genetic and environmental factors. Some studies have indicated that transforming growth factor beta(1) (TGF-beta(1)), a pleiotropic cytokine regulating inflammatory reactions and airway remodeling, may participate in the pathogenesis of asthma. Several polymorphisms have been described in the TGFB1 gene; some were tested in allergic asthma, with conflicting results. The aim of this study was to investigate the possible associations of four TGFB1 gene polymorphisms (-800G>A, -509C>T, 869T>C, and 915G>C) with allergic asthma in a Polish population. These four single nucleotide polymorphisms were genotyped in 247 asthmatic patients (including 207 atopic individuals) and 287 unrelated healthy volunteers by means of the polymerase chain reaction-restriction fragment length polymorphism method. No significant differences between patients and controls in allele, genotype, and haplotype frequencies were reported. Logistic regression analysis of genotype distribution and allele positivity adjusted for age and sex did not reveal any significant differences between all patients or patients selected for atopy and controls. Thus, no evidence was reported for a contribution of the TGFB1 gene to allergic asthma in a Polish population. The results are discussed in the context of similar studies in other populations.