The Molecular Mechanisms in Senescent Cells Induced by Natural Aging and Ionizing Radiation.

This review discusses the relationship between cellular senescence and radiation exposure. Given the wide range of ionizing radiation sources encountered by people in professional and medical spheres, as well as the influence of natural background radiation, the question of the effect of radiation on biological processes, particularly on aging processes, remains highly relevant. The parallel relationship between natural and radiation-induced cellular senescence reveals the common aspects underlying these processes. Based on recent scientific data, the key points of the effects of ionizing radiation on cellular processes associated with aging, such as genome instability, mitochondrial dysfunction, altered expression of miRNAs, epigenetic profile, and manifestation of the senescence-associated secretory phenotype (SASP), are discussed. Unraveling the molecular mechanisms of cellular senescence can make a valuable contribution to the understanding of the molecular genetic basis of age-associated diseases in the context of environmental exposure.

Molecular and Cellular Mechanism of Action of Chrysotile Asbestos in MRC5 Cell Line.

Asbestos is a known carcinogen; however, the influence of chrysotile asbestos on the development of tumor-related diseases remains a subject of intense debate within the scientific community. To analyze the effect of asbestos, we conducted a study using the MRC5 cell line. We were able to demonstrate that chrysotile asbestos stimulated the production of reactive oxygen species (ROS), leading to cell death and DNA damage in the MRC5 cell line, using various techniques such as ROS measurement, comet assay, MTT assay, and qPCR. In addition, we found that chrysotile asbestos treatment significantly increased extracellular mitochondrial DNA levels in the culture medium and induced significant changes in the expression profile of several miRNAs, which was the first of its kind. Thus, our research highlights the importance of studying the effects of chrysotile asbestos on human health and reveals multiple adverse effects of chrysotile asbestos.

The Role of Mitochondrial miRNAs in the Development of Radon-Induced Lung Cancer.

MicroRNAs are short, non-coding RNA molecules regulating gene expression by inhibiting the translation of messenger RNA (mRNA) or leading to degradation. The miRNAs are encoded in the nuclear genome and exported to the cytosol. However, miRNAs have been found in mitochondria and are probably derived from mitochondrial DNA. These miRNAs are able to directly regulate mitochondrial genes and mitochondrial activity. Mitochondrial dysfunction is the cause of many diseases, including cancer. In this review, we consider the role of mitochondrial miRNAs in the pathogenesis of lung cancer with particular reference to radon exposure.

The level of free-circulating mtDNA in patients with radon-induced lung cancer.

OBJECTIVE: According to the World Health Organization, radon is the second leading cause of lung cancer after smoking. Cell free circulating mitochondrial DNA (cf mtDNA) have been used not only as a biomarker of carcinogenesis but also as a biomarker of exposure to radiation, but nothing is known about changes in the level of cf mtDNA following radon exposure. Therefore, the purpose of this study was to estimate the cf mtDNA copy number as a biomarker of the response to radon exposure in lung cancer pathogenesis. METHODS: 207 subjects were examined including 41 radon-exposed lung cancer patients, 40 lung cancer patients without radon exposure and 126 healthy controls exposed/not exposed to high level of radon. Total cell free circulating DNA from blood samples was extracted and used to detect cell free circulating mitochondrial DNA copy number by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: Our data indicate that the level of cf mtDNA in the radon-induced lung cancer patients was significantly higher than that of the other study participants. There was a significant difference in the level of cf mtDNA in the blood plasma of healthy volunteers exposed and not exposed to high doses of radon. Moreover, in healthy volunteers living in areas with high radon levels, the mtDNA copy number was higher than that in patients with lung cancer who were not exposed to high doses of radon. CONCLUSION: Our study provides evidence for a possible role of cf mtDNA as a promising biomarker of lung cancer induced by exposure to high dose of radon.

The Plasma Levels of hsa-miR-19b-3p, hsa-miR-125b-5p, and hsamiR- 320c in Patients with Asthma, COPD and Asthma-COPD Overlap Syndrome (ACOS).

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.

Role of microRNAs in Lung Carcinogenesis Induced by Asbestos.

MicroRNAs are a class of small noncoding endogenous RNAs 19-25 nucleotides long, which play an important role in the post-transcriptional regulation of gene expression by targeting mRNA targets with subsequent repression of translation. MicroRNAs are involved in the pathogenesis of numerous diseases, including cancer. Lung cancer is the leading cause of cancer death in the world. Lung cancer is usually associated with tobacco smoking. However, about 25% of lung cancer cases occur in people who have never smoked. According to the International Agency for Research on Cancer, asbestos has been classified as one of the cancerogenic factors for lung cancer. The mechanism of malignant transformation under the influence of asbestos is associated with the genotoxic effect of reactive oxygen species, which initiate the processes of DNA damage in the cell. However, epigenetic mechanisms such as changes in the microRNA expression profile may also be implicated in the pathogenesis of asbestos-induced lung cancer. Numerous studies have shown that microRNAs can serve as a biomarker of the effects of various adverse environmental factors on the human body. This review examines the role of microRNAs, the expression profile of which changes upon exposure to asbestos, in key processes of carcinogenesis, such as proliferation, cell survival, metastasis, neo-angiogenesis, and immune response avoidance.

An investigation of the association between ADRB2 gene polymorphisms and asthma in Kazakh population.

INTRODUCTION: Beta-2-adrenergic receptor (ADRB2) is present in the cells of the respiratory tract, including bronchial smooth muscle cells and bronchial epithelium, and is a target for endogenous catecholamines and drugs used to treat the obstructive lung diseases. OBJECTIVES: This study aimed to investigate the possible association of the Arg16Gly and Gln27Glu polymorphisms of the ADRB2 gene with asthma and its endophenotypes in the Kazakh population. METHODS: A total of 70 asthmatic patients and 80 healthy controls were genotyped for Arg16Gly and Gln27Glu polymorphisms of the ADRB2 gene by using quantitative real-time polymerase chain reaction. Statistical analysis was performed with the Graph Pad InStat 7 Software. RESULTS: No associations between the asthma patients and healthy individuals were found when the allele and genotype distribution of Arg16Gly and Gln27Glu single nucleotide polymorphisms were compared. Analysis of the haplotype frequencies showed statistically significant differences between patients with asthma and controls for Arg16Gly/Gln27Gln and Arg16Gly/Gln27Glu haplotypes (odds ratio [OR] = 2.12, 95% confidence interval [CI] = 0.87-5.16 and OR = 2.25, 95% CI = 0.89-5.67 respectively). The Arg16 allele and Arg16Arg genotype frequencies were higher in patients with uncontrolled asthma than in controls (χ2 = 5.17, df = 1, P = 0.02 and χ2 = 5.36, df = 1, P = 0.02 respectively). CONCLUSION: The results of this study support the possible involvement of Arg16Gly polymorphism in the development of uncontrolled asthma, and indicate that Arg16Gly/Gln27Gln and Arg16Gly/Gln27Glu haplotypes are more common in asthma patients in the Kazakh population.

The Potential Role of miRNA-19b-3p and miRNA-320c in Patients with Moderate Bronchial Asthma.

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.