Genetic variations in detoxification enzymes and HIF-1α in Japanese patients with COPD

Association of hypoxia inducible factor 1-Alpha gene polymorphisms with multiple disease risks: A comprehensive meta-analysis

HIF1A gene polymorphisms have been confirmed the association with cancer risk through the statistical meta-analysis based on single genetic association (SGA) studies. A good number SGA studies also investigated the association of HIF1A gene with several other diseases, but no researcher yet performed statistical meta-analysis to confirm this association more accurately. Therefore, in this paper, we performed a statistical meta-analysis to draw a consensus decision about the association of HIF1A gene polymorphisms with several diseases except cancers giving the weight on large sample size. This meta-analysis was performed based on 41 SGA study’s findings, where the polymorphisms rs11549465 (1772 C/T) and rs11549467 (1790 G/A) of HIF1A gene were analyzed based on 11544 and 7426 cases and 11494 and 7063 control samples, respectively. Our results showed that the 1772 C/T polymorphism is not significantly associated with overall disease risks. The 1790 G/A polymorphism was significantly associated with overall diseases under recessive model (AA vs. AG + GG), which indicates that the A allele is responsible for overall diseases though it is recessive. The subgroup analysis based on ethnicity showed the significant association of 1772 C/T polymorphism with overall disease for Caucasian population under the all genetic models, which indicates that the C allele controls overall diseases. The ethnicity subgroup showed the significant association of 1790 G/A polymorphism with overall disease for Asian population under the recessive model (AA vs. AG + GG), which indicates that the A allele is responsible for overall diseases. The subgroup analysis based on disease types showed that 1772 C/T is significantly associated with chronic obstructive pulmonary disease (COPD) under two genetic models (C vs. T and CC vs. CT + TT), skin disease under two genetic models (CC vs. TT and CC + CT vs. TT), and diabetic complications under three genetic models (C vs. T, CT vs. TT and CC + CT vs. TT), where C allele is high risk factor for skin disease and diabetic complications (since, ORs > 1), but low risk factor for COPD (since, ORs < 1). Also the 1790 G/A variant significantly associated with the subgroup of cardiovascular disease (CVD) under homozygote model, diabetic complications under allelic and homozygote models, and other disease under four genetic models, where the A is high risk factor for diabetic complications and low risk factor for CVD. Thus, this study provided more evidence that the HIF1A gene is significantly associated with COPD, CVD, skin disease and diabetic complications. These might be the severe comorbidities and risk factors for multiple cancers due to the effect of HIF1A gene and need further investigations accumulating large number of studies.

Epigenetic Modifications and Therapy in Chronic Obstructive Pulmonary Disease (COPD): An Update Review

Chronic obstructive pulmonary disease (COPD) that is one of the most prevalent chronic adult diseases and the third leading cause of fatality until 2020. Elastase/anti-elastase hypothesis, chronic inflammation, apoptosis, oxidant-antioxidant balance and infective repair cause pathogenesis of COPD are among the factors at play. Epigenetic changes are post-translational modifications in histone proteins and DNA such as methylation and acetylation as well as dysregulation of miRNAs expression. In this update review, we have examined recent studies on the upregulation or downregulation of methylation in different genes associated with COPD. Dysregulation of HDAC activity which is caused by some factors and miRNAs plays a key role in the suppression and reduction of COPD development. Also, some therapeutic approaches are proposed against COPD by targeting HDAC2 and miRNAs, which have therapeutic effects.

MicroRNA-186 is associated with hypoxia-inducible factor-1α expression in chronic obstructive pulmonary disease

Background

MicroRNAs (miRNAs) are a family of small noncoding RNAs and are essential in the regulation of gene expression. Their impacts on gene expression have been reported in various diseases. The role of hypoxia‐inducible factor 1 alpha (HIF‐1α) in the development and progression of chronic obstructive pulmonary disease (COPD) has also been demonstrated. However, the role of microRNA‐186 (miR‐186) in relation to HIF in COPD is unknown.

Methods

Cell culture experiments were performed using human lung fibroblast cells (MRC‐5). Cell viability was determined by MTT and flow cytometry assays. Reverse transcriptase‐polymerase chain reaction (RT‐PCR) and Western blot analysis were used to assess the expression levels of HIF‐1α and inflammatory cytokines. Dual‐luciferase reporter assays were used to reveal the correlation between miR‐186 and HIF‐1α.

Results

After miR‐186 transfection, the cell lines showed reduced proliferation and increased apoptosis. After overexpression of miR‐186, we found that the HIF‐1α expression level was reduced in MRC‐5 cells. We found that miR‐186 can affect apoptosis of inflammatory fibroblasts through the regulation of HIF‐1α and affect the downstream signaling pathways.

Conclusions

These data suggested that miR‐186 contributes to the pathogenesis of COPD and that miRNA‐186 may also affect the HIF‐1α‐dependent lung structure maintenance program.

HIF1A gene rs10873142 polymorphism is associated with risk of chronic obstructive pulmonary disease in a Chinese Han population: a case-control study

Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by long-term poor airflow. Recently, variants in the hypoxia inducible factor 1α (HIF1A) gene were found to be associated with COPD risk. The present study aimed to identify whether rs10873142 polymorphism (an intronic polymorphism) in HIF1A gene was related to COPD in a Chinese population. We genotyped HIF1A gene rs10873142 polymorphism in a case–control study with 235 COPD cases and 548 controls in a Chinese Han population. Odd ratios (ORs) and 95% confidence intervals (CIs) were estimated using the chi-squared (χ²) test, genetic model analysis, and stratification analysis. In the genetic model analysis, we found that the TT genotype (TT compared with CC: OR: 1.63; 95% CI: 1.02–2.60; P=0.042) and T allele (T compared with C: OR: 1.29; 95%CI, 1.02–1.60; P=0.032) showed significant correlation with the risk of COPD. However, in stratification analyses of age, BMI, and forced expiratory volume in 1 s (FEV1)/FEV, we failed to find any association between HIF1A gene rs10873142 polymorphism with COPD risk. The present study supports that HIF1A gene rs10873142 polymorphism may be associated with increased risk of COPD in a Chinese Han population. To the best of our knowledge, this is the first case–control study uncovering that the HIF1A gene rs10873142 polymorphism increases the risk of COPD in a Chinese Han population.

The association of genetic polymorphisms of hypoxia inducible factor-1 alpha and vascular endothelial growth factor with increased risk of chronic obstructive pulmonary disease: A case-control study

Accumulated data over the years have suggested that hypoxia inducible factor-1 alpha (HIF-1α) and its downstream vascular endothelial growth factor (VEGF) gene may be linked with chronic obstructive pulmonary disease (COPD). This study aims to investigate the association of HIF-1α and VEGF genetic polymorphisms and their correlated risks with COPD. COPD patients (case group) and healthy individuals (control group) were recruited. DNA was extracted to detect HIF-1α and VEGF genetic polymorphisms. Basal lung volume and forced expiratory capacity in 1st second (FEV1)/forced vital capacity (FVC) and FEV₁/predicted value (pred)% were calculated. Genotype and allele distributions in HIF-1α and VEGF genes were analyzed. Kaplan-Meier curves and logistic regression model were used for analysis of survival and COPD risk factors. Haplotypes for HIF-1α rs11549465 and rs11549467 were analyzed. FEV₁/FVC and FEV1/pred% in the case group were lower than the control group. Frequencies of HIF-1α rs11549465 CT + TT genotype and T allele, and rs11549467 GA + AA genotype and A allele were higher in the case group than the control group. Patients with rs11549465 CT + TT had higher COPD risk than those with the CC genotype. Patients with rs11549467 GA + AA showed higher COPD risk and lower FEV₁/FVC and FEV₁/pred% than those with the GG genotype. Patients with HIF-1α TA haplotype showed higher COPD risk than those with the CG haplotype. Survival rate of patients with HIF-1α rs11549467 GG genotype was higher than those with the GA + AA genotype. HIF-1α rs11549467 polymorphism may be associated with COPD risk.

HIF1A gene polymorphisms and human diseases: Graphical review of 97 association studies

Hypoxia-inducible factors (HIFs) belong to a family of transcription factors (TF) responsive to a low O2 availability, which is often a characteristic feature of solid tumors. The alpha subunit of the HIF heterodimer is O2 -sensitive, and once stabilized in hypoxia, it functions as a master regulator of various genes involved in hypoxia pathway. Changes in the HIF1A (hypoxia inducible factor 1, alpha subunit) nucleotide sequence or expression has been shown to be associated with the development of several diseases. Because of increasing research interest in HIF1A gene a review of association studies was needed. We here reviewed published data on single nucleotide polymorphisms (SNPs) in HIF1A in various diseases; in total, 34 SNPs were tested for an association with 49 phenotypes, and the results were visualized using the Cytoscape software. Among all collected polymorphisms 16 SNPs showed significant associations with 40 different phenotypes, including six SNPs associated with 14 cancer types. Missense SNPs (rs11549465 and rs11549467) within the oxygen-dependent degradation domain were most frequently studied. The study provides a comprehensive tool for researchers working in this area and may contribute to more accurate disease diagnosis and identification of therapeutic targets.

Genetic polymorphism of heme oxygenase 1 promoter in the occurrence and severity of chronic obstructive pulmonary disease: a meta-analysis

Heme oxygenase 1 (HMOX1) plays an important role in the development of chronic obstructive pulmonary disease (COPD). However, the association of HMOX1 length polymorphism in promoter region to the risk and severity of COPD has not been well studied. In this study, we searched the databases including PubMed, EMBASE, Cochrane Library and China National Knowledge Infrastructure (CNKI) and extracted the information from related articles. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to study the effect of HMOX1 polymorphism on the risk and severity of COPD. As a result, nine studies were included for this meta‐analysis. Higher frequencies of L allele and type I genotype (containing at least one L allele) were found in patients with COPD (for L allele, OR 2.02, 95% CI: 1.32–3.11, P = 0.001; for type I genotype, OR 1.82, 95% CI: 1.28–2.61, P = 0.001), especially in Asian population (for L allele, OR 2.23, 95% CI: 1.68–2.95, P < 0.001; for type I genotype, OR 2.02, 95% CI: 1.51–2.70, P < 0.001). Genotyping method, source of control subjects, literature quality and language also affected the results to some extent. However, there was little difference in HMOX1 genotypes distribution in patients with COPD with different severity. Our study indicated L allele and type I genotype were related to the susceptibility but not the severity of COPD.

Impact of CYP1A1 Polymorphisms on Susceptibility to Chronic Obstructive Pulmonary Disease: A Meta-Analysis

Objective. Several studies have evaluated the association between CYP1A1 polymorphisms and the susceptibility of chronic obstructive pulmonary disease (COPD) with inconclusive results. We performed the first comprehensive meta-analysis to summarize the association between CYP1A1 polymorphisms and COPD risk. Method. A systematic literature search was conducted (up to April 2015) in five online databases: PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), WeiPu, and WanFang databases. The strength of association was calculated by odds ratio (OR) and corresponding 95% confidence interval (CI). Results. Seven case-control studies with 1050 cases and 1202 controls were included. Our study suggested a significant association between the MspI polymorphism and COPD risk (CC versus TC + TT: OR = 1.57, CI: 1.09–2.26, P = 0.02; CC versus TT: OR = 1.73, CI: 1.18–2.55, P = 0.005). For the Ile/Val polymorphism, a significant association with COPD risk was observed (GG versus AG + AA: OR = 2.75, CI: 1.29–5.84, P = 0.009; GG versus AA: OR = 3.23, CI: 1.50–6.93, P = 0.003; AG versus AA: OR = 1.39, CI: 1.01–1.90, P = 0.04). Subgroup analysis indicated a significant association between the MspI variation and COPD risk among Asians (CC versus TC + TT: OR = 1.70, CI: 1.06–2.71, P = 0.03; CC versus TT: OR = 1.84, CI: 1.11–3.06, P = 0.02). Conclusion. The MspI and Ile/Val polymorphisms might alter the susceptibility of COPD, and MspI polymorphism might play a role in COPD risk among Asian population.

HIF-1α genetic variants and protein expression confer the susceptibility and prognosis of gliomas

To investigate the role of HIF-1α genetic polymorphism of c.1772C>T and c.1790G>A in the incidence and prognosis of gliomas in a Chinese cohort, a total of 387 gliomas patients and 437 age- and sex-matched healthy controls were recruited. The genetic polymorphism of c.1772C>T and c.1790G>A was determined. We found that the genotype distribution at c.1772C>T showed significant difference between patients and controls. Multivariable analyses showed a significantly higher risk for gliomas in 1772TT genotype carriers (odds ratio 2.68, with CC as reference). In addition, we also found a significantly higher risk for grade III + IV gliomas was observed in 1772TT genotype carriers (odds ratio 2.21, with CC as reference). The overall survival rates in patients with 1772TT or 1772CT genotype were markedly lower compared with patients with CC (both P < 0.01). Our in vitro studies revealed that HIF-1α regulates the proliferation, migration and invasion of human glioma U251 cells. This study suggests that the c.1772C>T polymorphisms may be used as a molecular marker for gliomas occurrence, grades and clinical outcome in gliomas patients.

Polymorphism in the hypoxia-inducible factor 1alpha gene may confer susceptibility to LDD in Chinese cohort

Objective

This study aimed to investigate whether or not hypoxia-inducible factor-1α (HIF-1α) gene variants are associated with the susceptibility and clinical characteristics of lumbar disc degeneration (LDD).

Methods

We examined 320 patients with LDD and 447 gender- and age-matched control subjects. We also determined the HIF-1α gene variants, including C1772T (P582S) and G1790A (A588T) polymorphisms.

Results

Significant differences were observed in allelic and genotypic distributions of 1790 A > G polymorphisms between LDD cases and control subjects. Logistic regression revealed that 1790 AA genotypes indicated a protective effect against the development of LDD. The HIF-1α 1790 A > G polymorphisms also affected the severity of LDD as evaluated based on the modified Japanese Orthopedic Association (mJOA) scores. The 1790 AA genotype carriers exhibited significantly lower mJOA scores than AG and GG carriers. C1772T did not show any association with the risk and severity of LDD.

Conclusion

Our study suggested that HIF-1α 1790 A > G polymorphisms may be used as a molecular marker to determine the susceptibility and severity of LDD.