Background: Bronchial Asthma (BA) and Chronic Obstructive Pulmonary Disease (COPD) are chronic airway inflammation diseases. In recent years, patients with signs of both BA and COPD have been assigned to a separate group as Asthma-COPD Overlap Syndrome (ACOS). Free-circulating plasma microRNAs are considered as potential biomarkers of pulmonology diseases, including BA, COPD, and ACOS. Objective: This study aimed to investigate the expression level of free-circulating plasma microRNAs, hsa-miR-19b-3p, hsa-miR-125b-5p, and hsa-miR-320c in patients with BA, COPD and ACOS for the detection and validation of new microRNAs as biomarkers for chronic lung diseases. Methods: The relative expression levels of 720 microRNAs were evaluated by Real Time-Polymerase Chain Reaction (RT-PCR) in patients with COPD and BA. Three upregulated microRNAs (hsa-miR-19b-3p, hsa-miR-125b-5p and hsa-miR-320c) were selected for further study. The obtained data were analyzed using the microRNA PCR Array Data Analysis tool. The sensitivity and specificity were estimated using the area under the Receiver Operating Characteristics curve (ROC). Results: The expression level of free-circulating hsa-miR-19b-3p was decreased in the blood plasma of patients with BA and ACOS, and increased in patients with COPD. hsa-miR-125b-5p was downregulated in the blood plasma of patients with COPD and upregulated in patients with BA and ACOS. hsa-miR-320c was downregulated in the blood plasma of patients with BA, and upregulated in patients with COPD and ACOS. The ROC curves of patients with BA for hsa-miR-19b-3p, patients with ACOS for hsa-miR-125b-5p, and patients with COPD for hsa-miR-320c revealed the probability of them as valuable biomarkers with AUCs of 0.824, 0.825, and 0.855, respectively. Conclusion: Our study revealed three promising biomarkers for the diagnosis of COPD, BA and ACOS.

Background: Bronchial Asthma (BA) is a complex heterogeneous disease with a number of molecular immunopathological mechanisms underlying airway inflammation, hyperreactivity, and bronchial remodeling. MicroRNAs are important regulators in the pathogenesis and progression of chronic respiratory diseases, including BA. Objective: The aim of the study is to investigate the level of expression of cell-free circulating miR-19b-3p and miR-320c in the blood plasma by comparing their plasma levels with IL-4 in the moderate BA patients and control group. Methods: The level of expression miR-19b-3p and miR-320c were evaluated by qRT-PCR using the comparative threshold cycle (Ct) method. U6 small nuclear RNA was taken as an endogenous control. The content of IL - 4 in blood plasma was determined by using ELISA. Results: miR-19b-3p and miR-320c were significantly dysregulated in moderate asthmatic patients in comparison with control group. The area under the ROC curve of miR-19b-3p and miR-320c showed 0.8088 (95% CI 0.6925 to 0.9251, P value =0.0001) and 0,9048 (95% CI 0,7792 to 1,000, P value <0,0001), respectively. BA patients showed a considerably positive correlation between the expression level of microRNA-320c and IL-4 levels. Conclusion: These cell-free circulating microRNAs are probably deregulated in other inflammatory/ pathological diseases, so they could be useful to understand the molecular pathogenesis of BA or to investigate the “inflammatory reaction” in this disease.

Mucins are highly glycosylated proteins that form the structural basis of mucus and represent a key component of innate immunity at mucosal surfaces, particularly in the respiratory tract. Beyond their mechanical barrier function, mucins actively participate in pathogen trapping, regulation of mucociliary clearance, modulation of inflammatory responses, and maintenance of epithelial homeostasis. Dysregulation of mucin synthesis, composition, or transport contributes to mucus hypersecretion, impaired airway clearance, and chronic inflammation in respiratory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. This review summarizes current insights into mucin biology, including their biosynthesis, structure, classification, and regulation, with emphasis on the gel-forming mucins MUC5AC and MUC5B. The role of mucins in mechanical protection, host–pathogen interactions, control of inflammation, and coordination of innate immune responses is reviewed. Attention is given to the interplay between mucins, immune cells, and microbial communities in maintaining airway barrier integrity. The article further examines mucoactive therapeutic strategies aimed at restoring mucus barrier function. Expectorants, mucolytics, mucoregulators, and mucokinetic agents are reviewed with respect to their mechanisms of action and clinical relevance. Established drugs, including N-acetylcysteine, carbocysteine, dornase alfa, ambroxol, and hypertonic solutions, are considered alongside emerging molecular targets such as NF-κB-dependent regulation of mucin expression, calcium-activated chloride channels, MARCKS-mediated mucin exocytosis, purinergic signaling pathways, and NO/cGMP signaling. Non-pharmacological approaches, including airway clearance techniques and respiratory rehabilitation, are covered concisely. Conclusions: Overall, this review highlights mucins as dynamic regulators of innate immunity and underscores the need for mechanism-based, personalized mucoactive therapies to improve outcomes in chronic inflammatory airway diseases.

Background/Objectives: Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory lung disease characterized by irreversible airway obstruction. This study aims to investigate the associations between COPD and its phenotypes with polymorphic variants of the IREB2 and CHRNA5 genes in the Kazakhstan population. Methods: A case–control study was conducted involving 265 COPD patients and 267 controls. Genotyping of the IREB2 polymorphisms rs13180 and rs2568494, as well as CHRNA5 rs16969968 polymorphism, was performed using real-time polymerase chain reactions (Real-Time PCRs). Results: A higher frequency of the AA genotype of the IREB2 rs2568494 polymorphism was identified in COPD patients with moderate to very severe airflow obstruction (Chronic Obstructive Lung Disease (GOLD) stages II, III, and IV), with an odds ratio of 0.69 (95% CI = 0.23–2.10; Padj = 0.03). The IREB2 rs13180 polymorphism was significantly more frequent or prevalent in smokers and showed a correlation with FEV₁ (forced expiratory volume in one second) (β = 7.79, SE = 2.98, p = 0.01) and FEV₁/ FVC (forced vital capacity) (β = 9.51, SE = 2.95, p = 0.002). Additionally, the CC genotype of this polymorphism was associated with clinical manifestations of COVID-19 in COPD patients (χ²= 3,95, df = 2, p = 0.05). Conclusions: Our study identified a significant association between the IREB2 rs2568494 polymorphism and an increased risk of severe COPD. The IREB2 rs13180 polymorphism was linked to smoking behavior, as well as key lung function indicators, suggesting its potential role in disease progression and lung damage. Furthermore, the CC genotype of the IREB2 rs13180 polymorphism was associated with clinical manifestations of COVID-19 in COPD patients, indicating a potential impact of this genetic variant on susceptibility to viral infections in this population.