Personalizing and targeting therapy for COPD: the role of molecular and clinical biomarkers

The role of CISD1 reduction in macrophages in promoting COPD development through M1 polarization and mitochondrial dysfunction

BACKGROUND

The mitochondrial dysfunction and oxidative stress imbalance caused by macrophage polarization play a role in the progression of COPD, with CDGSH iron-sulfur domain-containing protein 1 (CISD1) playing a key role. This study revealed the role and mechanism of CISD1 in smoke-induced macrophages.

METHODS

Using a pure cigarette smoke exposure-induced COPD mouse model, stimulation of Raw264.7 macrophages with cigarette smoke extract mimics the COPD environment. Knocking down CISD1 expression in macrophages and combining it with high-throughput sequencing to obtain subsequent differentially expressed genes and pathways. Macrophage polarization tendency under different treatments was determined using flow cytometry. Meanwhile, Mitosox, JC-1, DCFH-DA fluorescence intensity was measured to detect mitochondrial function and cellular oxidative stress levels. Western Blot technique was employed to validate autophagy (mitochondrial autophagy) pathway-related proteins. In addition, Elisa technique was used to measure inflammatory factors (IL-6, TNF-a) in the cell supernatant after co-culturing macrophages (Raw264.7) with epithelial cells (MLE12).

RESULTS

CISD1 is underexpressed in peripheral blood monocytes of COPD patients. Under in vitro conditions, we verified that cigarette smoke (smoke extract) indeed inhibits CISD1 expression in macrophages. Subsequently, we found that macrophages with knocked-down CISD1 tend to polarize towards M1 phenotype, and exhibit signs of mitochondrial dysfunction and oxidative stress imbalance. In addition, we observed significant activation of the autophagy pathway in CISD1-inhibited macrophages, with upregulation of LC3A/B and downregulation of p62 protein, as well as increased expression of mitochondrial autophagy-related proteins (PINK1, PARKN). Furthermore, co-culturing CISD1-knockdown macrophages (Raw264.7) with epithelial cells (MLE12) resulted in upregulation of inflammatory factors in the supernatant.

CONCLUSIONS

Smoke-induced reduction of CISD1 in macrophages promotes M1 polarization and mitochondrial dysfunction by activating the autophagy pathway, thereby promoting the occurrence and development of COPD.

Epigenetic regulation of macrophage activation in chronic obstructive pulmonary disease

Macrophages in the innate immune system play a vital role in various lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), acute lung injury and pulmonary fibrosis. Macrophages involved in the process of immunity need to go through a process of activation, including changes in gene expression and cell metabolism. Epigenetic modifications are key factors of macrophage activation including DNA methylation, histone modification and non-coding RNA regulation. Understanding the role and mechanisms of epigenetic regulation of macrophage activation can provide insights into the function of macrophages in lung diseases and help identification of potential therapeutic targets. This review summarizes the latest progress in the epigenetic changes and regulation of macrophages in their development process and in normal physiological states, and the epigenetic regulation of macrophages in COPD as well as the influence of macrophage activation on COPD development.

Exploring Molecular Mechanisms and Biomarkers in COPD: An Overview of Current Advancements and Perspectives

Chronic obstructive pulmonary disease (COPD) plays a significant role in global morbidity and mortality rates, typified by progressive airflow restriction and lingering respiratory symptoms. Recent explorations in molecular biology have illuminated the complex mechanisms underpinning COPD pathogenesis, providing critical insights into disease progression, exacerbations, and potential therapeutic interventions. This review delivers a thorough examination of the latest progress in molecular research related to COPD, involving fundamental molecular pathways, biomarkers, therapeutic targets, and cutting-edge technologies. Key areas of focus include the roles of inflammation, oxidative stress, and protease-antiprotease imbalances, alongside genetic and epigenetic factors contributing to COPD susceptibility and heterogeneity. Additionally, advancements in omics technologies-such as genomics, transcriptomics, proteomics, and metabolomics-offer new avenues for comprehensive molecular profiling, aiding in the discovery of novel biomarkers and therapeutic targets. Comprehending the molecular foundation of COPD carries substantial potential for the creation of tailored treatment strategies and the enhancement of patient outcomes. By integrating molecular insights into clinical practice, there is a promising pathway towards personalized medicine approaches that can improve the diagnosis, treatment, and overall management of COPD, ultimately reducing its global burden.

Chronic Obstructive Pulmonary Disease Molecular Subtyping and Pathway Deviation-Based Candidate Gene Identification

OBJECTIVE

The aim of this study was to identify the molecular subtypes of chronic obstructive pulmonary disease (COPD) and to prioritize COPD candidate genes using bioinformatics methods.

MATERIALS AND METHODS

In this bioinformatics study, the gene expression dataset GSE76705 (including 229 COPD samples) and known COPD-related genes (candidate genes) were downloaded from the Gene Expression Omnibus (GEO) and the Online Mendelian Inheritance in Man (OMIM) databases respectively. Based on the expression values of the candidate genes, COPD samples were divided into molecular subtypes through hierarchical clustering analysis. Candidate genes were accordingly allocated into the defined molecular subtypes and functional enrichment analysis was undertaken. Pathway deviation scores were then analyzed, followed by the analysis of clinical indicators (FEV1, FEV1/FVC, age and gender) of COPD patients in each subtype, and prediction models were constructed. Furthermore, the gene expression dataset GSE71220 was used to bioinformatically validate our results.

RESULTS

A total of 213 COPD-related genes were identified, which divided samples into three subtypes based on the gene expression values. After intersection analysis, 160 common genes including transforming growth factor β1 (TGFB1), epidermal growth factor receptor (EGFR) and interleukin 13 (IL13) were obtained. Functional enrichment analysis identified 22 pathways such as 'hsa04060: cytokine-cytokine receptor interaction pathways, 'hsa04110: cell cycle' and 'hsa05222: small cell lung cancer'. Pathways in subtype 2 had higher deviation scores. Furthermore, three receiver operating characteristic (ROC) curves (accuracies >80%) were constructed. The three subtypes in COPD samples were also identified in the validation dataset GSE71220.

CONCLUSION

COPD may be further subdivided into several molecular subtypes, which may be useful in improving COPD therapy based on the molecular subtype of a patient.

Pharmacological strategies to reduce exacerbation risk in COPD: a narrative review

Identifying patients at risk of exacerbations and managing them appropriately to reduce this risk represents an important clinical challenge. Numerous treatments have been assessed for the prevention of exacerbations and their efficacy may differ by patient phenotype. Given their centrality in the treatment of COPD, there is strong rationale for maximizing bronchodilation as an initial strategy to reduce exacerbation risk irrespective of patient phenotype. Therefore, in patients assessed as frequent exacerbators (>1 exacerbation/year) we propose initial bronchodilator treatment with a long-acting muscarinic antagonist (LAMA)/ long-acting β2-agonist (LABA). For those patients who continue to experience >1 exacerbation/year despite maximal bronchodilation, we advocate treating according to patient phenotype. Based on currently available data on adding inhaled corticosteroids (ICS) to a LABA, ICS might be added to a LABA/LAMA combination in exacerbating patients who have an asthma-COPD overlap syndrome or high blood eosinophil counts, while in exacerbators with chronic bronchitis, consideration should be given to treating with a phosphodiesterase (PDE)-4 inhibitor (roflumilast) or high-dose mucolytic agents. For those patients who experience frequent bacterial exacerbations and/or bronchiectasis, addition of mucolytic agents or a macrolide antibiotic (e.g. azithromycin) should be considered. In all patients at risk of exacerbations, pulmonary rehabilitation should be included as part of a comprehensive management plan.

Biomarkers of progression of chronic obstructive pulmonary disease (COPD)

Disease progression of chronic obstructive pulmonary disease (COPD) is variable, with some patients having a relatively stable course, while others suffer relentless progression leading to severe breathlessness, frequent acute exacerbations of COPD (AECOPD), respiratory failure and death. Radiological markers such as CT emphysema index, bronchiectasis and coronary artery calcification (CAC) have been linked with increased mortality in COPD patients. Molecular changes in lung tissue reflect alterations in lung pathology that occur with disease progression; however, lung tissue is not routinely accessible. Cell counts (including neutrophils) and mediators in induced sputum have been associated with lung function and risk of exacerbations. Examples of peripheral blood biological markers (biomarkers) include those associated with lung function (reduced CC-16), emphysema severity (increased adiponectin, reduced sRAGE), exacerbations and mortality [increased CRP, fibrinogen, leukocyte count, IL-6, IL-8, and tumor necrosis factor α (TNF-α)] including increased YKL-40 with mortality. Emerging approaches to discovering markers of gene-environment interaction include exhaled breath analysis [volatile organic compounds (VOCs), exhaled breath condensate], cellular and systemic responses to exposure to air pollution, alterations in the lung microbiome, and biomarkers of lung ageing such as telomere length shortening and reduced levels of sirtuins. Overcoming methodological challenges in sampling and quality control will enable more robust yet easily accessible biomarkers to be developed and qualified, in order to optimise personalised medicine in patients with COPD.