SERPINA1 methylation and lung function in tobacco-smoke exposed European children and adults: a meta-analysis of ALEC population-based cohorts

Testing Alpha-1 Antitrypsin Deficiency in Black Populations

Alpha-1 antitrypsin (AAT) deficiency (AATD) is an under-recognized hereditary disorder and a significant cause of chronic obstructive pulmonary disease (COPD), a disease that contributes to global mortality. AAT is encoded by the SERPINA1 gene, and severe mutation variants of this gene increase the risk of developing COPD. AATD is more frequently screened for in non-Hispanic White populations. However, AATD is also observed in other ethnic groups and very few studies have documented the mutation frequency in these other ethnic populations. Here, we review the current literature on AATD and allele frequency primarily in Black populations and discuss the possible clinical outcomes of low screening rates in a population that experiences poor health outcomes and whether the low frequency of AATD is related to a lack of screening in this population or a truly low frequency of mutations causing AATD. This review also outlines the harmful SERPINA1 variants, the current epidemiology knowledge of AATD, health inequity in Black populations, AATD prevalence in Black populations, the clinical implications of low screening of AATD in this population, and the possible dangers of not diagnosing or treating AATD.

SERPINA1 and More? A Putative Genetic Contributor to Pulmonary Dysfunction in Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency (AATD) is a common inherited disorder associated with an increased risk of pulmonary disease. Its clinical presentation, including the nature and severity of organ involvement, is highly variable and unpredictable and is not as strongly linked to genotype and environmental exposure (e.g., smoking history) as might be expected. Significant differences were observed within matched populations of severe AATD patients regarding risk of complications, age at onset, and disease course, including the dynamics of lung function decline. Genetic factors are among the putative modifiers contributing to the clinical variability in AATD, yet their role remains elusive. Here, we review and summarise our current understanding of epigenetic and genetic modifiers of pulmonary dysfunction in subjects with AATD.

SERPINA1 Methylation Levels are Associated with Lung Cancer Development in Male Patients with Chronic Obstructive Pulmonary Disease

Purpose

The mechanism of lung cancer (LC) in male patients with chronic obstructive pulmonary disease (COPD) has not been well understood, and the early diagnosis is currently challenging. The study aimed to explore the association of DNA methylation levels with LC development in male COPD patients.

Patients and Methods

A total of 147 male participants were divided into four groups, ie, COPD+LC group, COPD group, LC group, and control (CON) group. The methylation levels of human serine protease inhibitor A1 (SERPINA1) and the serum levels of inflammatory biomarkers were compared among groups. Multivariate logistic regression was performed to explore the correlation of inflammatory biomarkers and gene methylation with lung cancer combining COPD.

Results

SERPINA1 methylation levels were significantly higher in the COPD+LC group than that in the COPD group and LC group, respectively (all p < 0.05). The serum levels of interleukin (IL)-1β, IL-17, and transforming growth factor (TGF)-β1 were significantly higher in the COPD+LC group than in the LC group (all p < 0.05). The SERPINA1 methylation levels were positively correlated with the IL-1β levels (r = 0.5188, p = 0.0012). The AUC (area under curve) of SERPINA1 methylation for the diagnosis of LC in COPD was 0.677 (sensitivity of 52.2% and specificity of 78.2%).

Conclusion

The methylation of SERPINA1 is linked to LC in patients with COPD. The SERPINA1 methylation levels were positively correlated with the IL-1β levels. These findings may be of diagnostic value.

Smoking related attention alteration in chronic obstructive pulmonary disease-smoking comorbidity

Background

Chronic obstructive pulmonary disease (COPD) is a respiratory disease that causes a wide range of cognitive impairments. Although COPD-Smoking comorbidity is common, the relationship between smoking and cognitive function in COPD-Smoking comorbidity remains unclear. This study aimed to investigate the effect of smoking on cognitive function like attention in COPD-Smoking patients.

Methods

In this study, we used the Montreal Cognitive Assessment (MoCA) scale and resting-state functional magnetic resonance imaging (fMRI) to explore the effect of smoking on attention in patients with COPD.

Results

Behavioral analysis revealed that among patients with COPD the smokers had a shorter course of COPD and showed a worse attention performance than the non-smokers. Resting-state fMRI analysis revealed that among patients with COPD smokers showed lower regional homogeneity (ReHo) value of the fusiform gyrus than non-smokers. Importantly, the ReHo of the fusiform gyrus is positively associated with attention and mediates the effect of smoking on attention in COPD.

Conclusions

In summary, our study provides behavioral and neurobiological evidence supporting the positive effect of smoking on attention in COPD. This may be helpful for understanding and treating COPD and even other diseases comorbid with smoking.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01964-6.

Association of Single Nucleotide Polymorphism rs17580 with Smoking and Pulmonary Tuberculosis

This study aimed to investigate the correlation between SERPINA1 single nucleotide polymorphism (SNP) rs17580, smoking, and pulmonary tuberculosis (TB). A total of 420 TB patients (observation group) and 640 patients without pulmonary disease (control group) were randomly included. The frequencies of different genotypes were counted in both groups, and the correlation between SNP genotypes and the occurrence of TB was analyzed. Statistical models were performed to analyze the correlation between rs17580 and TB and the correlation between rs17580. The frequencies of genotypes TT, TA, and AA at the rs17580 locus in patients with TB were not statistically different from those in the control group ( $P>0.05$ ), and the distributions of the two groups were in accordance with the Hardy–Weinberg equilibrium law. rs17580 was analyzed in dominant, recessive, and codominant models, exhibiting no statistical difference ( $P>0.05$ ). There was no significant difference among the three genotypes in the 1–5 typing (χ2 = 1.034, $P=0.998$ ), and the difference between T and C was not statistically significant (χ2 = 0.012, $P=0.999$ ). There was a significant difference between the three genotypes between the smoking group and the nonsmoking group in TB patients ( $P<0.05$ ). There was no significant difference among three genotypes in the alcoholic group and the nonalcoholic group in TB patients ( $P>0.05$ ). There was no statistical difference in the time to cure among the 3 genotypes in TB patients ( $P>0.05$ ). A type mutation of rs17580 in the SERPINA1 gene was strongly associated with a higher risk of development of TB in smoking patients.

A Review of Alpha-1 Antitrypsin Binding Partners for Immune Regulation and Potential Therapeutic Application

Alpha-1 antitrypsin (AAT) is the canonical serine protease inhibitor of neutrophil-derived proteases and can modulate innate immune mechanisms through its anti-inflammatory activities mediated by a broad spectrum of protein, cytokine, and cell surface interactions. AAT contains a reactive methionine residue that is critical for its protease-specific binding capacity, whereby AAT entraps the protease on cleavage of its reactive centre loop, neutralises its activity by key changes in its tertiary structure, and permits removal of the AAT-protease complex from the circulation. Recently, however, the immunomodulatory role of AAT has come increasingly to the fore with several prominent studies focused on lipid or protein-protein interactions that are predominantly mediated through electrostatic, glycan, or hydrophobic potential binding sites. The aim of this review was to investigate the spectrum of AAT molecular interactions, with newer studies supporting a potential therapeutic paradigm for AAT augmentation therapy in disorders in which a chronic immune response is strongly linked.

Methylation of SERPINA1 gene promoter may predict chronic obstructive pulmonary disease in patients affected by acute coronary syndrome

Background

Diagnostic biomarkers for detecting chronic obstructive pulmonary disease (COPD) in acute coronary syndrome (ACS) patients are not available. SERPINA1, coding for the most potent circulating anti-inflammatory protein in the lung, has been found to be differentially methylated in blood cells from COPD patients. This study aimed to investigate the methylation profile of SERPINA1 in blood cells from ACS patients, with (COPD+) or without COPD (COPD−).

Methods

Blood samples were from 115 ACS patients, including 30 COPD+ and 85 COPD− according to lung function phenotype, obtained with spirometry. DNA treated with sodium bisulfite was PCR-amplified at SERPINA1 promoter region. Methylation analysis was carried out by sequencing the PCR products. Lymphocytes count in ACS patients was recorded at hospital admission and discharge.

Results

SERPINA1 was hypermethylated in 24/30 (80%) COPD+ and 48/85 (56.5%) COPD− (p < 0.05). Interestingly, at hospital discharge, lymphocytes count was higher in COPD− patients carrying SERPINA1 hypermethylated (1.98 × 10³ ± 0.6 cell/µl) than in COPD− carrying SERPINA1 hypomethylated (1.7 × 10³ ± 0.48 cell/µl) (p < 0.05).

Conclusions

SERPINA1 is hypermethylated in blood cells from COPD+ patients. COPD− carrying SERPINA1 hypermethylated and high lymphocytes count may be at risk of COPD development. Therefore, SERPINA1 hypermethylation may represent a potential biomarker for predicting COPD development in ACS patients.

Age-Related Macular Degeneration: From Epigenetics to Therapeutic Implications

Aberrant regulation of epigenetic mechanisms, including the two most common types; DNA methylation and histone modification have been implicated in common chronic progressive conditions, including Alzheimer disease, cardiovascular disease, and age-related macular degeneration (AMD). All these conditions are complex, meaning that environmental factors, genetic factors, and their interactions play a role in disease pathophysiology. Although genome wide association studies (GWAS), and studies on twins demonstrate the genetic/hereditary component to these complex diseases, including AMD, this contribution is much less than 100%. Moreover, the contribution of the hereditary component decreases in the advanced, later onset forms of these chronic diseases including AMD. This underscores the need to elucidate how the genetic and environmental factors function to exert their influence on disease pathophysiology. By teasing out epigenetic mechanisms and how they exert their influence on AMD, therapeutic targets can be tailored to prevent and/or slow down disease progression. Epigenetic studies that incorporate well-characterized patient tissue samples (including affected tissues and peripheral blood), similar to those relevant to gene expression studies, along with genetic and epidemiological information, can be the first step in developing appropriate functional assays to validate findings and identify potential therapies.

SERPINA1 Gene Promoter Is Differentially Methylated in Peripheral Blood Mononuclear Cells of Pregnant Women

SERine Protein INhibitor-A1 (SERPINA1) is an inducible blood cell gene coding for alpha1-antitrypsin (AAT), a plasma protease inhibitor whose circulating levels are raised during inflammation, infection and advanced pregnancy. DNA methylation has been suggested to play a role in SERPINA1 gene expression regulation in peripheral blood mononuclear cells (PBMCs). The methylation status of SERPINA1 in PBMCs is unknown. The aim of this study was to evaluate the methylation profile of the SERPINA1 promoter in PBMC. To this purpose PBMCs and serum were collected from healthy subjects (HS) (n = 75), including blood donors (BD) (n = 25), pregnant women at early pregnancy (EP) (n = 25), i.e., within the first trimester, and pregnant women at late pregnancy (LP) (n = 25), i.e., at the third trimester. DNA from PBMCs was treated with sodium bisulfite and PCR amplified for SERPINA1 gene promoter, followed by sequencing analyses. AAT serum levels were determined by ELISA test. SERPINA1 was found hypermethylated in 58.7% of HS. The prevalence of SERPINA1 hypermethylation was significantly higher in BD (68%) and EP (88%) than in LP (20%) (p < 0.01). The median serum AAT concentration was 1.07, 0.63, and 3.15 mg/ml in BD, EP, and LP, respectively (p < 0.05, BD and EP vs LP). This study indicates, for the first time, that SERPINA1 gene promoter is differentially methylated in PBMCs from HS. Likely, modulation of the methylation may be a novel epigenetic regulator mechanism of AAT expression in the PBMC of HS. Therefore, SERPINA1 gene promoter methylation may represent an epigenetic biomarker of PBMCs in healthy subjects.

The time window of pet ownership exposure modifies the relationship of Environmental Tobacco Smoke with lung function: A large population-based cohort study

There is a large body of evidence linking Environmental Tobacco Smoke (ETS) exposure with impaired lung function. However, it is not known whether exposure to pets modifies this relationship. To investigate if pet ownership changes the association between ETS exposure and lung function, a population-based sample of 7326 children, 7-14 years old, were randomly recruited from 24 districts in northeast China. Lung function including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), peak expiratory flow (PEF), and maximal mid-expiratory flow (MMEF) was measured by spirometry, while pet ownership time periods and ETS exposure were collected by questionnaire. Two-level regression analysis was done, with covariates controlled for. The results showed pet exposure in certain early lifetime windows modified the associations of ETS exposure on decreased lung function in children. Among children exposed to current ETS, those exposed to pets in utero had greater reductions in lung function (for instance: OR for reduced FVC (<85% predicted) = 10.86; 95% CI: 3.80-30.97) than those not exposed to pets in utero (OR = 2.32; 95% CI: 1.76-3.05) (p_interaction = 0.005). While, children exposed to current pet ownership reduced the lung function impairment induced by ETS exposure during the first 2 years of life and/or ETS exposure during pregnancy, especially for FVC impairment. For instance, OR (95%CI) for reduced FVC (<85% predicted) was 0.81 (0.56, 1.18) and 1.42 (1.15, 1.74), respectively, for children with or without current pet ownership exposed to ETS during the first 2 years of life (p_interaction = 0.010). Furthermore, pet type or number of pets did not significantly modify associations between ETS exposure and lung function. In conclusion, the timing of pet ownership modified associations between ETS exposure and lung function, pet ownership in utero and during the first 2 years of life significantly worsened the adverse impacts of passive smoking on lung function.

The etiologic origins for chronic obstructive pulmonary disease

COPD, characterized by long-term poorly irreversible airway limitation and persistent respiratory symptoms, has resulted in enormous challenges to human health worldwide, with increasing rates of prevalence, death, and disability. Although its origin was thought to be in the interactions of genetic with environmental factors, the effects of environmental factors on the disease during different life stages remain little known. Without clear mechanisms and radical cure for it, early screening and prevention of COPD seem to be important. In this review, we will discuss the etiologic origins for poor lung function and COPD caused by specific adverse effects during corresponding life stages, as well as try to find new insights and potential prevention strategies for this disease.