Serum levels of trace minerals and heavy metals in severe COPD patients with and without pulmonary hypertension

Quantitative profiling and baseline intervals of trace elements in healthy lung tissues

BACKGROUND

Human lung tissue, as an interface with the environment, is susceptible to various environmental pollutants, including trace metals. However, quantitative data on trace metals in human lung tissues remain poorly described.

METHODS

This study aimed to characterize the elemental composition of histologically healthy, unaffected parts of human lung tissues, associated with non-infective, non-infiltrative, and non-malignant diseases (n = 60) for essential (Cr, Mn, Fe, Co, Cu, Zn, and Se) and toxic trace elements (Sr, Ni, As, Cd, and Pb). Additionally, we investigated the influence of personal factors (sex, age, and smoking habits) on the examined trace element profiles, as well as between the trace elements correlations in the healthy human lungs.

RESULTS

Among the analyzed trace elements, Fe was the most prevalent, while As was the least prevalent in healthy lung tissues. Stratifying by age revealed significantly higher Cr and Co (less Sr, Ni, and Pb) and lower Se levels in older individuals (above 65 years) compared to their younger counterparts. Sex-based differences were also notable, with Cu and Co 1.2- and 2.3-fold higher levels in females than in males. Exploring the impact of smoking habits revealed a striking 10-fold increase in Cd levels in the lung tissues of smokers compared to non-smokers. Correlation analyses showed significant positive associations between concentrations of certain toxic and essential trace elements in healthy lung tissues.

CONCLUSIONS

This study could contribute to the establishment of baseline intervals for essential and toxic trace elements, valuable for toxicological and clinical assessment, in healthy, unaffected human lungs, and indicates the influence of sex, age, and smoking. However, further larger-scale studies are needed to make more stable conclusions.

Associations of blood cadmium and lead concentrations with all-cause mortality in US adults with chronic obstructive pulmonary disease

BACKGROUND

Some literature indicates an association between exposure to cadmium and lead and the presence of emphysema and chronic bronchitis, which are the two primary components of COPD. Understanding whether there is a potential association between cadmium and lead exposure and higher mortality rates in individuals with COPD could provide profound insights into the long-term effects of these two metal exposures on human health.

METHODS

This study included 2024 patients with COPD in the US from the NHANES from 1999 through 2016 who were followed up to 2019. Multivariable Cox regression models were used to calculate HRs and 95 % CIs for all-cause mortality in relation to blood cadmium and lead concentrations. Plotting Kaplan-Meier curves and Restricted cubic spline curves to visualize results. Furthermore, stratified and sensitivity analyses were conducted.

RESULTS

After multivariate adjustment, blood cadmium and blood lead concentrations were independently associated with an increased risk of all-cause mortality. Compared with the first tertile, the HRs of all-cause mortality associated with the blood cadmium concentration were 1.74 (95 % CI, 1.22-2.49) in the second tertile and 1.89 (95 % CI, 1.31-2.72) in the third tertile. The HRs of all-cause mortality associated with the blood lead concentration were 1.13 (95 % CI, 0.84-1.51) in the second tertile and 1.43 (95 % CI, 1.05-1.93) in the third tertile.

CONCLUSION

This study found that increased blood cadmium and blood lead concentrations were associated with increased all-cause mortality in COPD patients. Reducing cadmium and lead exposure could potentially mitigate mortality risk in these individuals. More prospective studies are needed in the future to demonstrate our findings.

A hypothesis: Potential contributions of metals to the pathogenesis of pulmonary artery hypertension

Pulmonary artery hypertension (PAH) is characterized by vasoconstriction and vascular remodeling resulting in both increased pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP). The chronic and high-pressure stress experienced by endothelial cells can give rise to inflammation, oxidative stress, and infiltration by immune cells. However, there is no clearly defined mechanism for PAH and available treatment options only provide limited symptomatic relief. Due to the far-reaching effects of metal exposures, the interaction between metals and the pulmonary vasculature is of particular interest. This review will briefly introduce the pathophysiology of PAH and then focus on the potential roles of metals, including essential and non-essential metals in the pathogenic process in the pulmonary arteries and right heart, which may be linked to PAH. Based on available data from human studies of occupational or environmental metal exposure, including lead, antimony, iron, and copper, the hypothesis of metals contributing to the pathogenesis of PAH is proposed as potential risk factors and underlying mechanisms for PAH. We propose that metals may initiate or exacerbate the pathogenesis of PAH, by providing potential mechanism by which metals interact with hypoxia-inducible factor and tumor suppressor p53 to modulate their downstream cellular proliferation pathways. These need further investigation. Additionally, we present future research directions on roles of metals in PAH.

A review on the potential risks and mechanisms of heavy metal exposure to Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is a chronic disease that affects patients as well as the health and economic stability of society as a whole. At the same time, heavy metal pollution is widely recognized as having a possible impact on the environment and human health. Therefore, these diseases have become important global public health issues. In recent years, researchers have shown great interest in the potential association between heavy metal exposure and the development of COPD, and there has been a substantial increase in the number of related studies. However, we still face the challenge of developing a comprehensive and integrated understanding of this complex association. Therefore, this review aimed to evaluate the existing epidemiological studies to clarify the association between heavy metal exposure and COPD. In addition, we will discuss the biological mechanisms between the two to better understand the multiple molecular pathways and possible mechanisms of action involved, and provide additional insights for the subsequent identification of potential strategies to prevent and control the effects of heavy metal exposure on the development of COPD in individuals and populations.

Arsenic exposure and lung function decline in chronic obstructive pulmonary disease patients: The mediating influence of systematic inflammation and oxidative stress

Lung tissue is one of the target sites of arsenic (As). The goal of this investigation was to assess the associations of blood As concentration with pulmonary function indicators in patients with chronic obstructive pulmonary disease (COPD), as well as the roles of systemic inflammation and oxidative stress in this relationship. All 791 COPD patients were selected. Blood As concentration, and tumour necrosis factor-α (TNF-α) and 8-iso-prostaglandin-F2α (8-iso-PGF2α) were detected in the serum of COPD cases. Blood As was robustly related to pulmonary function parameters in an inverse dose-dependent manner. Multivariate linear regression analyses verified that a 1-unit increase of blood As was linked to declines of 0.263 L in FVC, 0.288 L in FEV1, 3.454 in FEV1/FVC%, and 0.538 in predicted FEV1%, respectively. The potential for pulmonary function decline gradually increased across the elevated tertiles of blood As. Nonsmokers were susceptible to As-induced pulmonary function reduction. Blood As was positively linked to the levels of TNF-α and 8-iso-PGF2α. Increased TNF-α and 8-iso-PGF2α partially mediated As-induced the reductions in FEV1 and FVC among COPD patients. As exposure is intensely linked to pulmonary function reduction. Systematic inflammation and oxidative stress partially mediate such associations in COPD patients.

Potential Roles of Metals in the Pathogenesis of Pulmonary and Systemic Hypertension

Pulmonary and systemic hypertension (PH, SH) are characterized by vasoconstriction and vascular remodeling resulting in increased vascular resistance and pulmonary/aortic artery pressures. The chronic stress leads to inflammation, oxidative stress, and infiltration by immune cells. Roles of metals in these diseases, particularly PH are largely unknown. This review first discusses the pathophysiology of PH including vascular oxidative stress, inflammation, and remodeling in PH; mitochondrial dysfunction and metabolic changes in PH; ion channel and its alterations in the pathogenesis of PH as well as PH-associated right ventricular (RV) remodeling and dysfunctions. This review then summarizes metal general features and essentiality for the cardiovascular system and effects of metals on systemic blood pressure. Lastly, this review explores non-essential and essential metals and potential roles of their dyshomeostasis in PH and RV dysfunction. Although it remains early to conclude the role of metals in the pathogenesis of PH, emerging direct and indirect evidence implicates the possible contributions of metal-mediated toxicities in the development of PH. Future research should focus on comprehensive clinical metallomics study in PH patients; mechanistic evaluations to elucidate roles of various metals in PH animal models; and novel therapy clinical trials targeting metals. These important discoveries will significantly advance our understandings of this rare yet fatal disease, PH.

Metallomic Signatures of Lung Cancer and Chronic Obstructive Pulmonary Disease

Lung cancer (LC) is the leading cause of cancer deaths, and chronic obstructive pulmonary disease (COPD) can increase LC risk. Metallomics may provide insights into both of these tobacco-related diseases and their shared etiology. We conducted an observational study of 191 human serum samples, including those of healthy controls, LC patients, COPD patients, and patients with both COPD and LC. We found 18 elements (V, Al, As, Mn, Co, Cu, Zn, Cd, Se, W, Mo, Sb, Pb, Tl, Cr, Mg, Ni, and U) in these samples. In addition, we evaluated the elemental profiles of COPD cases of varying severity. The ratios and associations between the elements were also studied as possible signatures of the diseases. COPD severity and LC have a significant impact on the elemental composition of human serum. The severity of COPD was found to reduce the serum concentrations of As, Cd, and Tl and increased the serum concentrations of Mn and Sb compared with healthy control samples, while LC was found to increase Al, As, Mn, and Pb concentrations. This study provides new insights into the effects of LC and COPD on the human serum elemental profile that will pave the way for the potential use of elements as biomarkers for diagnosis and prognosis. It also sheds light on the potential link between the two diseases, i.e., the evolution of COPD to LC.

Molecular regulation and therapeutic implications of cell death in pulmonary hypertension

Pulmonary hypertension (PH) is a clinical and pathophysiological syndrome caused by changes in pulmonary vascular structure or function that results in increased pulmonary vascular resistance and pulmonary arterial pressure, and it is characterized by pulmonary endothelial dysfunction, pulmonary artery media thickening, pulmonary vascular remodeling, and right ventricular hypertrophy, all of which are driven by an imbalance between the growth and death of pulmonary vascular cells. Programmed cell death (PCD), different from cell necrosis, is an active cellular death mechanism that is activated in response to both internal and external factors and is precisely regulated by cells. More than a dozen PCD modes have been identified, among which apoptosis, autophagy, pyroptosis, ferroptosis, necroptosis, and cuproptosis have been proven to be involved in the pathophysiology of PH to varying degrees. This article provides a summary of the regulatory patterns of different PCD modes and their potential effects on PH. Additionally, it describes the current understanding of this complex and interconnected process and analyzes the therapeutic potential of targeting specific PCD modes as molecular targets.

Association between cadmium exposure and pulmonary function reduction: Potential mediating role of telomere attrition in chronic obstructive pulmonary disease patients

BACKGROUND

Environmental cadmium (Cd) exposure is linked to pulmonary function injury in the general population. But, the association between blood Cd concentration and pulmonary function has not been investigated thoroughly in chronic obstructive pulmonary disease (COPD) patients, and the potential mechanisms are unclear.

METHODS

All eligible 789 COPD patients were enrolled from Anhui COPD cohort. Blood specimens and clinical information were collected. Pulmonary function test was conducted. The subunit of telomerase, telomerase reverse transcriptase (TERT), was determined through enzyme linked immunosorbent assay (ELISA). Blood Cd was measured via inductively coupled-mass spectrometer (ICP-MS).

RESULTS

Blood Cd was negatively and dose-dependently associated with pulmonary function. Each 1-unit increase of blood Cd was associated with 0.861 L decline in FVC, 0.648 L decline in FEV1, 5.938 % decline in FEV1/FVC %, and 22.098 % decline in FEV1 % among COPD patients, respectively. Age, current-smoking, self-cooking and higher smoking amount aggravated Cd-evoked pulmonary function decrease. Additionally, there was an inversely dose-response association between Cd concentration and TERT in COPD patients. Elevated TERT obviously mediated 29.53 %, 37.50 % and 19.48 % of Cd-evoked FVC, FEV1, and FEV1 % declines in COPD patients, respectively.

CONCLUSION

Blood Cd concentration is strongly associated with the decline of pulmonary function and telomerase activity among COPD patients. Telomere attrition partially mediates Cd-induced pulmonary function decline, suggesting an underlying mechanistic role of telomere attrition in pulmonary function decline from Cd exposure in COPD patients.

The Serum Levels of the Heavy Metals Cu, Zn, Cd, and Pb and Progression of COPD-A Preliminary Study

There is evidence in previous studies that high levels of heavy metals may play a key role in the development of COPD due to the induction of chronic inflammation and oxidative stress. In this preliminary study, we used atomic absorption spectrophotometry to measure the levels of four heavy metals (Cu, Zn, Cd, and Pb) in blood serum of COPD patients and controls over 2 years. Clinical data on disease progression or absence were collected in patients living in the industrial region of Stara Zagora, Bulgaria. The mean values of Cu in the serum of patients with COPD and the control group were 374.29 ± 15.03 μg/L and 238.55 ± 175.31 μg/L, Zn—2010.435 ± 670.006 μg/L and 1672.78 ± 934.27 μg/L, Cd—0.334 ± 0.0216 μg/L and 0.395 ± 0.110 μg/L and Pb—0.0732 ± 0.009 μg/L and 0.075 ± 0.0153 μg/L. This is probably because these elements are biogenic and are used in the body for its anti-oxidant protection. In fact, it cannot be stated with certainty that elevated levels of Cu and Zn in the environment have a negative impact in COPD patients. There was a trend towards higher levels of the toxicants lead and cadmium in COPD patients compared to the control group of patients. There is a statistically unproven trend toward higher levels of lead and cadmium in COPD patients compared to controls, which to some extent supports our hypothesis that there is a relationship between environmental lead and cadmium levels and the COPD manifested. In COPD patients, a positive correlation was found between BMI and serum Cu levels (r = 0.413, p = 0.005). A higher concentration of serum Cu was found in men with BMI ≥ 30, compared to those with BMI < 30. There is also a positive correlation to a lesser extent between CRP and cadmium (r = 0.380; p = 0.019) and lead (r = 0.452; p = 0.004). The correlation of lead and cadmium with PSA also shows that these elements may also be associated with the presence of inflammatory processes. A significant negative correlation exists between Pb in the serum of patients with COPD and their blood hemoglobin (r = −356; p = 0.028). The results of our study suggest that higher doses of the trace elements Cu and Zn do not always have a negative effect in patients with COPD, while the toxicants Pb and Cd may be involved in COPD exacerbation and can be used as prognostic biomarkers for progression. Further studies are warranted to confirm these preliminary results.

Metallomics in pulmonary arterial hypertension patients

Pulmonary arterial hypertension (PAH) prevalence is increasing worldwide, and the prognosis is poor with 5-year survival < 50% in high risk patients. The relationship between metal exposure/essential metal dyshomeostasis and PAH/right ventricular dysfunction is less investigated. The aim of this study is to investigate vegetable consumptions and metal levels between PAH patients and controls. This was a prospective, single center pilot study. Questionnaires were completed by all study subjects (20 PAH patients and 10 healthy controls) on smoking, metal exposure risks, metal supplements, and vegetable consumptions. Blood and urine samples were collected to measure 25 metal levels in blood, plasma, and urine using an X Series II quadrupole inductively coupled plasma mass spectrometry. Statistical analysis was conducted using SAS 9.5 and results with p value < 0.05 were considered significant. Vegetables consumptions (broccoli risk ratio [RR] = 0.4, CI = (0.2, 0.9)], cabbage [RR = 0.2, CI = (0.1, 0.8)], and brussel sprouts [RR = 0.2, CI = (0.1, 0.5)]) are associated with less risks of PAH. In the plasma samples, silver (p < 0.001), and copper (p = 0.002) levels were significantly higher in PAH patients. There was significant positive correlation between cardiac output and cardiac index with plasma levels of silver (r = 0.665, p = 0.001 and r = 0.678 p = 0.001), respectively. There was significant correlation between mixed venous saturation, 6-min walk distance, and last BNP with plasma levels of chromium (r = -0.520, p = 0.022; r = -0.55, p = 0.014; r = 0.463, p = 0.039), respectively. In conclusion, there are significant differences between PAH and control groups in terms of vegetable consumptions and metal concentrations. Silver and chromium levels are correlated with clinical indicators of PAH severities.

Effects of Different Concentrations of Oil Mist Particulate Matter on Pulmonary Fibrosis In Vivo and In Vitro

Oil-mist particulate matter (OMPM) refers to oily particles with a small aerodynamic equivalent diameter in ambient air. Since the pathogenesis of pulmonary fibrosis (PF) has not been fully elucidated, this study aims to explore the potential molecular mechanisms of the adverse effects of exposure to OMPM at different concentrations in vivo and in vitro on PF. In this study, rats and cell lines were treated with different concentrations of OMPM in vivo and in vitro. Sirius Red staining analysis shows that OMPM exposure could cause pulmonary lesions and fibrosis symptoms. The expression of TGF-β1, α-SMA, and collagen I was increased in the lung tissue of rats. The activities of MMP2 and TIMP1 were unbalanced, and increased N-Cadherin and decreased E-Cadherin upon OMPM exposure in a dose-dependent manner. In addition, OMPM exposure could activate the TGF-β1/Smad3 and TGF-β1/MAPK p38 signaling pathways, and the differentiation of human lung fibroblast HFL-1 cells. Therefore, OMPM exposure could induce PF by targeting the lung epithelium and fibroblasts, and activating the TGF-β1/Smad3 and TGF-β1/MAPK p38 signaling pathways.

Adverse pulmonary impacts of environmental concentrations of oil mist particulate matter in normal human bronchial epithelial cell

Airborne oil mist particulate matter (OMPM) is generated during industrial processes such as metalworking and may be associated with pulmonary dysfunction. In this study, we employed the normal human bronchial epithelial BEAS-2B cell line to elucidate the association between pulmonary toxicity and OMPM of 2.5-10 μm, 1.0-2.5 μm and <1.0 μm particle sizes (OMPM_10-2.5, OMPM_2.5-1.0 and OMPM_1.0). We measured OMPM concentrations at a precision machinery factory to estimate lung deposition rates and select realistic environmental concentrations for testing. All OMPMs (1-50 μg/cm²) significantly decreased BEAS-2B cell viability (>38% of control), except for low-dose OMPM_1.0 (1 μg/cm²). OMPM_10-2.5 and OMPM_2.5-1.0, but not OMPM_1.0, induced oxidative stress (1.5-4-fold increase compared with the control) and increased the production of proinflammatory cytokines (1.5-3-fold). However, only OMPM_1.0 induced pulmonary epithelial barrier dysfunction via depletion of zonula occludens (0.65-0.8-fold) and α1-antitrypsin proteins (0.65-0.8-fold). In conclusion, a higher risk of lung disease was associated with smaller particle size OMPM. Exposure to OMPM_1.0 may be a potential risk factor for chronic obstructive pulmonary disease. The evidence also demonstrates that occupational exposure to OMPM may cause pulmonary disease at very low concentrations.

Serum cadmium positively correlates with inflammatory cytokines in patients with chronic obstructive pulmonary disease

BACKGROUND

Cadmium is a ubiquitous toxic heavy metal and environmental toxicant. Inflammation exerts central roles in the process of chronic obstructive pulmonary disease (COPD). However, few epidemiological studies on the correlation between cadmium exposure and COPD are available. The aim of this study was to evaluate the correlations among serum cadmium, inflammatory cytokines and pulmonary function in COPD patients.

METHODS

All 940 COPD patients were finally recruited in this study. Demographic characteristics and clinical information were extracted. Fasting serum was collected. Serum cadmium was detected through graphite furnace atomic absorption spectrophotometry. Serum inflammatory cytokines were measured using enzyme-linked immunosorbent assay.

RESULTS

All patients were classified into three groups according to the tertile division of serum cadmium concentration: low (<0.77 μg/L, L), medium (0.77-1.01 μg/L, M), and high (1.01 μg/L, H). Logistic regression analysis found that serum cadmium was inversely correlated with pulmonary function before and after adjusted confounding variables. When stratified by gender, serum cadmium was still negatively correlated with pulmonary function in COPD patients. Moreover, higher serum cadmium elevated CAT (COPD Assessment Test) score before and after adjusted confounding variables. Though a non-linear association between serum cadmium and inflammatory cytokines, serum cadmium was positively associated with inflammatory cytokines (TNF-α and MCP-1). TNF-α and MCP-1 exerted a partial mediator in the association between cadmium exposure and pulmonary function decline in COPD patients.

CONCLUSIONS

Serum cadmium concentration is inversely correlated with pulmonary function among COPD patients. Inflammatory cytokines may be important mediators for cadmium-induced pulmonary function decline in COPD patients.

Pulmonary toxicity of actual alveolar deposition concentrations of ultrafine particulate matters in human normal bronchial epithelial cell

Air pollution is a major worldwide concern, and exposure to particulate matter (PM) can increase the risks of pulmonary diseases. Normal human bronchial epithelial cells were applied to clarify the role of ultrafine PM (UFPM) in the pathogenesis of pulmonary toxic effects with realistic alveolar deposition doses. The UFPM used in this research originated from vehicular emissions and coal combustion. UFPM exposure of up to 72 h was found to induce significant time- and concentration-dependent decreases in cell viability. Exposure to UFPM increased reactive oxygen species (ROS) accumulation through heme oxygenase-1 (HO-1) inhibition and induced massive oxidative stress that increased the interleukin-8 (IL-8) expression. UFPM also reduced the pulmonary trans-epithelial electrical resistance through the depletion of zonula occludens (ZO) proteins. Finally, UFPM decreased the α1-antitrypsin (A1AT) expression, which implies high risk of chronic obstructive pulmonary disease (COPD). The evidence demonstrates that exposure to UFPM, even at very low concentrations, may affect the functions of the respiratory system.

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.

Elemental and mutational analysis of lung tissue in lung adenocarcinoma patients

Background

This study aimed to observe the association between trace element concentrations in lung tissue from lung adenocarcinoma cancer (LADC) patients and mutations in the epidermal growth factor receptor (EGFR) and KRAS genes.

Methods

LADC patients who had undergone lung resection were included in this study. Furthermore, twenty patients without lung cancer were included in this study as the control group. Samples were separately collected from both tumor and peritumor tissues. The mutational status was assessed for EGFR mutations, ALK rearrangements and KRAS mutations. Based on these analyses, patients were grouped into three groups: EGFR mutation, KRAS mutation and wild-type groups. The concentrations of various trace elements in the lung tissues were measured by a particle-induced X-ray emission (PIXE) system, and the results were analyzed for statistical significance.

Results

A total of 110 LADC patients were included in this study. The median age was 70 years, and 60% of the participants were female. Moreover, 18% and 20% of patients were EGFR- and KRAS-positive, respectively. Thirty-two trace elements were measured, and 18 trace elements were detectable. The concentrations of Fe, Co, Ni, Cu, Zn and Br were significantly higher in the KRAS mutation and wild-type groups than in the control group regardless of whether the samples were from tumor or peritumor tissues. For these 6 trace elements, the concentrations were significantly higher in smokers than in non-smokers. Considering the effect of smoking, differences in the trace element concentrations between each mutational group remained.

Conclusions

Trace elements in the lung may play a role in development of LADC in both smokers and never-smokers. However, prospective studies with larger sample sizes are needed to support this hypothesis.

Role of miRNA-181a-2-3p in cadmium-induced inflammatory responses of human bronchial epithelial cells

Background

Inflammation is an important priming event in the pathogenesis of pulmonary diseases, including chronic obstructive pulmonary disease (COPD). Increasing evidence indicates that microRNAs (miRNAs) contribute to the pathogenesis of COPD by regulating inflammatory response. Therefore, it is necessary to investigate novel molecular targets in COPD without any validation in COPD samples in airway inflammation. The aim of our study is to reveal novel miRNAs that can influence molecular targets for COPD and to examine the underlying mechanism in airway inflammation.

Methods

We identified the downregulation of miR-181a-2-3p in the serum of COPD patients and further investigated the role of miR-181a-2-3p in cadmium (Cd)-induced inflammation of a human bronchial epithelial cell line (BEAS-2B) and normal human bronchial epithelial (NHBE) cells.

Results

Our results showed that expression of miR-181a-2-3p was significantly decreased in Cd-treated cells and silencing of miR-181a-2-3p enhanced Cd-induced inflammatory responses and inflammasome activation. This negative regulatory effect of miR-181a-2-3p on inflammation is partly mediated by the calcium signaling pathway. Furthermore, global gene expression profiling revealed that Toll-like receptor 4 or sequestosome 1 genes were identified as potential targets of miR-181a-2-3p, which were significantly upregulated by knockdown of miR-181a-2-3p in Cd-treated cells.

Conclusions

Our results strongly suggest that miR-181a-2-3p has a critical role in Cd-induced inflammation of airway by regulating its potential target genes, which could be molecular targets for COPD.