Low 15d-PGJ2 status is associated with oxidative stress in chronic obstructive pulmonary disease patients

Histone lactylation-induced premature senescence contributes to 1-nitropyrene-Induced chronic obstructive pulmonary disease

Our previous study revealed that mice exposed to 1-nitropyrene (1-NP) develop pulmonary fibrosis and senescent alveolar cells. However, the impacts of chronic 1-NP on chronic obstructive pulmonary disease (COPD) and the underlying mechanism are unclear. Our research suggested that chronic 1-NP evoked alveolar structure damage, inflammatory cell infiltration, and pulmonary function decline in mice. Moreover, 1-NP increased p53 and p21 expression, the number of β-galactosidase-positive cells, and cell cycle arrest in mouse lungs and MLE-12 cells. Moreover, 1-NP promoted glycolysis and upregulated lactic dehydrogenase A (LDHA) and lactate production in mouse lungs and MLE-12 cells. Elevated glycolysis provoked histone lactylation, but not histone acetylation in pulmonary epithelial cells. Mechanistically, histone H3 lysine 14 lactylation (H3K14la) was upregulated in pulmonary epithelial cells. P53 knockdown mitigated 1-NP-induced cell cycle arrest and senescence in MLE-12 cells. CUT&Tag and ChIP-qPCR experiments confirmed that increased H3K14la directly upregulated p53 transcription in pulmonary epithelial cells. As expected, LDHA knockdown alleviated 1-NP-triggered cell cycle arrest and senescence in MLE-12 cells. In addition, supplementation with oxamate, an inhibitor of LDH, attenuated 1-NP-incurred premature senescence and the COPD-like phenotype in mice. These data revealed for the first time that histone lactylation-induced the increase in p53 transcription contributes to pulmonary epithelial cell senescence during 1-NP-induced COPD progression. Our results provide a basis for repressing lactate production as a promising therapeutic strategy for COPD.

Associations of Vitamin D With GPX4 and Iron Parameters in Chronic Obstructive Pulmonary Disease Patients: A Case-Control Study

Background: Vitamin D deficiency elevates the risk of chronic obstructive pulmonary disease (COPD) patients. Iron parameters elevation and glutathione peroxidase 4 (GPX4) reduction are involved in the process of COPD. The goal is to explore the associations of vitamin D with GPX4 and iron parameters in COPD patients through a case-control study. Methods: COPD patients and control subjects were enrolled. Serum samples and lung tissues were collected. Serum vitamin D and iron levels and pulmonary ferritin and GPX4 expressions were determined. In addition, human pulmonary epithelial cells (BEAS-2B) were incubated with 1,25(OH)2D3 (100 nM), the active form of vitamin D3. Then, vitamin D receptor (VDR) and nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) signaling were detected. Results: In patients with COPD, serum 25-hydroxyvitamin D (25(OH)D) decreased, and iron and ferritin levels in serum and lung tissues increased. Furthermore, pulmonary expression of GPX4 was reduced. Correlative analyzes indicated that lung function was inversely correlated with iron parameters and positively correlated with GPX4. The results showed that serum 25(OH)D deficiency was associated with an elevation in serum iron parameters and a reduction in pulmonary GPX4. In addition, VDR- and Nrf-2-positive lung nuclei were decreased in COPD patients than in control subjects. In patients with COPD, the results indicated a positive relationship between VDR and Nrf-2. Further analysis revealed that Nrf-2-positive nuclei were negatively correlated with iron parameters. In vitro experiments found that 1,25(OH)2D3 treatment activated VDR signaling and elevated the expression of Nrf-2 and GPX4 in BEAS-2B cells. Conclusions: Vitamin D deficiency is positively associated with GPX4 reduction and iron parameters elevation in COPD patients. It is recommended to explore the role of vitamin D supplementation in the progression of COPD.

Benzo[a]pyrene evokes epithelial-mesenchymal transition and pulmonary fibrosis through AhR-mediated Nrf2-p62 signaling

Benzo[a]pyrene (BaP) and its metabolic end product benzo(a)pyren-7,8-dihydrodiol-9,10-epoxide (BPDE), are known toxic environmental pollutants. This study aimed to analyze whether sub-chronic BPDE exposure initiated pulmonary fibrosis and the potential mechanisms. In this work, male C57BL6/J mice were exposed to BPDE by dynamic inhalation exposure for 8 weeks. Our results indicated that sub-chronic BPDE exposure evoked pulmonary fibrosis and epithelial-mesenchymal transition (EMT) in mice. Both in vivo and in vitro, BPDE exposure promoted nuclear translocation of Snail. Further experiments indicated that nuclear factor erythroid 2-related factor 2 (Nrf2) and p62 were upregulated in BPDE-exposed alveolar epithelial cells. Moreover, Nrf2 siRNA transfection evidently attenuated BPDE-induced p62 upregulation. Besides, p62 shRNA inhibited BPDE-incurred Snail nuclear translocation and EMT. Mechanically, BPDE facilitated physical interaction between p62 and Snail in the nucleus, then repressed Snail protein degradation by p62-dependent autophagy-lysosome pathway, and finally upregulated transcriptional activity of Snail. Additionally, aryl hydrocarbon receptor (AhR) was activated in BPDE-treated alveolar epithelial cells. Dual-luciferase assay indicated activating AhR could bind to Nrf2 gene promoter. Moreover, pretreatment with CH223191 or α-naphthoflavone (α-NF), AhR antagonists, inhibited BPDE-activated Nrf2-p62 signaling, and alleviated BPDE-induced EMT and pulmonary fibrosis in mice. Taken together, AhR-mediated Nrf2-p62 signaling contributes to BaP-induced EMT and pulmonary fibrosis.

Amelioration of Oxidative Stress in Rats with Chronic Obstructive Pulmonary Disease through Shenqi Huatan Decoction Activation of Peroxisome Proliferator-Activated Receptor Gamma-Mediated Activated Protein Kinase/Forkhead Transcription Factor O3a Signaling Pathway

Background

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease. Currently, no specific treatment strategy has been established; therefore, finding new treatment methods is essential. Clinically, Shenqi Huatan Decoction (SQHT) is a traditional Chinese medicinal formula for COPD treatment; however, its mechanism of action in treatment needs to be clarified.

Methods

The COPD rat model was replicated by cigarette smoking and tracheal injection using the LPS method. The control group and the SQHT groups were treated with dexamethasone and SQHT by gavage, respectively. After treatment, superoxide dismutase (SOD) serum levels, total antioxidant capacity (TAOC), lipid peroxidation, and malondialdehyde (MDA) were detected by enzyme-linked immunosorbent assay (ELISA). Activated protein kinase alpha (AMPK-α), forkhead transcription factor O3a (FOXO3a), manganese SOD (MnSOD), and peroxisome proliferator-activated receptor gamma (PPARγ) were detected using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and Western blot. Microribonucleic acid and protein expression levels were measured, and pathological changes in lung tissue were observed using hematoxylin and eosin staining.

Results

The pathological findings suggested that SQHT substantially affects COPD treatment by enhancing alveolar fusion and reducing emphysema. ELISA results showed that SQHT could lower the blood levels of MDA and lipid peroxide and raise SOD and TAOC levels, suggesting that it could lessen oxidative stress. In the lung tissue of rats with COPD, large doses of SQHT intervention dramatically increased AMPK protein expression, AMPK-α, FOXO3a, MnSOD, and PPARγ, indicating that SQHT may reduce oxidative stress by activating the PPARγ-mediated AMPK/FOXO3a signaling pathway. Similar results were obtained using RT-qPCR.

Conclusion

SQHT is effective for COPD treatment. The mechanism of action may be related to the activation of the PPARγ-mediated AMPK/FOXO3a signaling pathway to improve oxidative stress in lung tissue.

Arsenic exposure and pulmonary function decline: Potential mediating role of TRAIL in chronic obstructive pulmonary disease patients

BACKGROUND

Environmental arsenic (As) exposure is strongly related to the progression of chronic obstructive pulmonary disease (COPD). Pulmonary epithelial cells apoptosis is implicated in the pathophysiological mechanisms of COPD. However, the role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), one biomarker of apoptosis, remains unclear in As-mediated pulmonary function alternations in COPD patients.

METHODS

This study included 239 COPD patients. The serum level of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was measured by enzyme-linked immunosorbent assay (ELISA). The blood As level was determined through inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Blood As levels exhibited a negative and dose-dependent correlation with pulmonary function. Per unit elevation of blood arsenic concentrations was related to reductions of 0.339 L in FEV1, 0.311 L in FVC, 1.171% in FEV1/FVC%, and 7.999% in FEV1% in COPD subjects. Additionally, a positive dose-response correlation of blood As with serum TRAIL was found in COPD subjects. Additionally, the level of serum TRAIL was negatively linked to lung function. Elevated TRAIL significantly mediated As-induced decreases of 11.05%, 13.35%, and 31.78% in FVC, FEV1, and FEV1%, respectively among the COPD patients.

CONCLUSION

Blood As level is positively correlated with pulmonary function decline and serum TRAIL increase in individuals with COPD. Our findings suggest that elevated TRAIL levels may serve as a mediating mechanism through which As contributes to declining lung function in COPD patients.

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.