DKK1 Positively Correlates with Lung Function in COPD Patients and Reduces Airway Inflammation

Causal relationship between chronic obstructive pulmonary disease and BMD at different sites: A bidirectional Mendelian randomization study

Observational studies have demonstrated a correlation between chronic obstructive pulmonary disease (COPD) and osteoporosis (OP). However, it is unclear whether there is genetic causality between COPD and bone mineral density (BMD) reduction at different sites. This study assessed the causal relationship between COPD and BMD in various anatomical locations. Data associated with COPD and BMD were obtained from published genome-wide association studies (GWAS). We selected single nucleotide polymorphisms (SNPs) that were strongly associated with COPD and BMD could serve as instrumental variables for the analysis. Inverse variance weighted, MR-Egger and weighted median were manipulated to evaluate causality. Subsequently, we conducted heterogeneity tests using Cochran Q test and tested for pleiotropy using the MR-Egger intercept. We performed leave-one-out sensitivity analysis to assess the robustness of the results. Additionally, we obtained more accurate causal genetic associations by removing any pleiotropic outlying SNPs and performed Mendelian randomization (MR) analysis with the remaining data. Our findings established that COPD was negatively associated with Heel-BMD (odds ratio[OR] = 0.978, 95% confidence interval [CI] = 0.966, 0.990, P = .0003) but not LS-BMD (OR = 0.981, 95% CI: 0.943, 1.020, P = .335), FA-BMD (OR = 0.984, 95% CI: 0.927, 1.046, P = .616), and FN-BMD (OR = 0.981, 95% CI: 0.950, 1.014, P = .249). In reverse MR analysis, the results showed no significant causal effect of BMD at different sites on COPD. The results were proved to be dependable and steady by sensitivity, heterogeneity, and pleiotropy analysis. We found that COPD increases the risk of decreased heel BMD, however, there is no evidence that the loss of BMD increases the risk of COPD.

Mechanistic Regulation of Wnt Pathway-Related Progression of Chronic Obstructive Pulmonary Disease Airway Lesions

Chronic obstructive pulmonary disease (COPD) is a chronic disease associated with inflammation and structural changes in the airways and lungs, resulting from a combination of genetic and environmental factors. This interaction highlights significant genes in early life, particularly those involved in lung development, such as the Wnt signaling pathway. The Wnt signaling pathway plays an important role in cell homeostasis, and its abnormal activation can lead to the occurrence of related diseases such as asthma, COPD, and lung cancer. Due to the fact that the Wnt pathway is mechanically sensitive, abnormal activation of the Wnt pathway by mechanical stress contributes to the progression of chronic diseases. But in the context of COPD, it has received little attention. In this review, we aim to summarize the important current evidence on mechanical stress through the Wnt pathway in airway inflammation and structural changes in COPD and to provide potential targets for COPD treatment strategies.

SIRS tanılı hastalarda enflamasyon ve kemik döngüsü arasındaki ilişkinin sklerostin ve Dickkopf-1 (DKK-1) düzeyleri ile değerlendirilmesi

Introduction: In intensive care units (ICU), patients remain bedridden for a long time. In addition, severe infections are frequently seen in ICUs. Both prolonged immobilization and serious infections are associated with bone tissue loss. The Wnt pathway has recently been focused on evaluating bone tissue loss. The Wnt pathway participates in both infections and the formation of bone tissue. Wnt pathway inhibitors sclerostin and Dickkopf-1 (DKK-1) inhibit bone formation and increase osteoclastic activity. In this study, we aimed to examine bone turnover by the Wnt inhibitors sclerostin and DKK-1 and their possible associations with inflammation in SIRS patients.Methods: We included 30 patients diagnosed with systemic inflammatory response syndrome (SIRS) in the study group and 16 in the control group. Serum sclerostin, DKK-1, white blood cell (WBC), and C-Reactive Protein (CRP) levels on the day of SIRS diagnosis (basal), the 7th, 14th, and 21stdays were evaluated in the study group, and the results were compared with the control group.Results: When the control group was compared with the basal SIRS, there was a significant elevation in both sclerostin (p=0.003) and DKK-1 (p=0.001). Statistical analysis showed significant decreases in sclerostin levels between basal and the 7th, 14th, and 21st days (p=0.033, p=0.003, p=0.002, respectively). Similarly, significant decreases in DKK-1 levels between basal and the 7th and 21st days (p=0.015, p=0.001, respectively) and an insignificant decrease on the 14th day (p=0.191) was observed. Sclerostin was positively and significantly correlated with WBC and CRP in basal and 7th-day measurements and WBC in 7th and 14th days. DKK-1 is positively and significantly correlated with WBC in basal and 7th-daymeasurements, while DKK-1 negatively correlates with CRP in basal-7th-day measurements.Conclusion: In this study, it was shown for the first time that the Wnt antagonists sclerostin and DKK-1 values are high in SIRS patients in ICU. Both biomarker levels decreased in parallel with the treatment. However, it could not be associated with disease severity and inflammatory marker levels. We believe that monitoring the change of Wnt antagonists will be useful in demonstrating bone turnover in patients with SIRS.Keywords: Dickkopf-1, Intensive care unit, Sclerostin, Systemic inflammatory response syndrome, Wnt signaling pathway, Bone turnover                        

Regulatory roles of external cholesterol in human airway epithelial mitochondrial function through STARD3 signalling

BACKGROUND

Hypercholesterolemia is found in patients with chronic lung inflammation, during which airway epithelial cells play important roles in maintenance of inflammatory responses to pathogens. The present study aims at molecular mechanisms by which cholesterol changes airway epithelial sensitivity in response to smoking.

METHODS

Human bronchial epithelial cells (HBEs) were stimulated with cigarette smoke extract (CSE) and mice were exposed to CS/lipopolysaccharide (LPS) as models in vitro and in vivo. Severe COPD patients and healthy volunteers were also enrolled and the level of cholesterol in plasma was detected by metabolomics. Filipin III and elisa kits were used to stain free cholesterol. Mitochondrial function was detected by mitotracker green, mitotracker green, and Seahorse. Mitochondrial morphology was detected by high content screening and electron microscopy. The mRNA and protein levels of mitochondrial dynamics-related proteins were detected by RT-qPCR and Western blot,respectively. BODIPY 493/503 was used to stain lipid droplets. Lipidomics was used to detect intracellular lipid components. The mRNA level of interleukin (IL)-6 and IL-8 were detected by RT-qPCR.

RESULTS

We found that the cholesterol overload was associated with chronic obstructive pulmonary disease (COPD) and airway epithelia-driven inflammation, evidenced by hypercholesterolemia in patients with COPD and preclinical models, alteration of lipid metabolism-associated genes in CSE-induced airway epithelia and production of ILs. External cholesterol altered airway epithelial sensitivity of inflammation in response to CSE, through the regulation of STARD3-MFN2 pathway, cholesterol re-distribution, altered transport and accumulation of cholesterol, activities of lipid transport regulators and disorder of mitochondrial function and dynamics. MFN2 down-regulation increased airway epithelial sensitivity and production of ILs after smoking, at least partially by injuring fatty acid oxidation and activating mTOR phosphorylation.

CONCLUSIONS

Our data provide new insights for understanding molecular mechanisms of cholesterol-altered airway epithelial inflammation and for developing diagnostic biomarkers and therapeutic targets to improve patient outcomes.