Forthcoming complications in recovered COVID-19 patients with COPD and asthma; possible therapeutic opportunities.

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been growing swiftly worldwide. Patients with background chronic pulmonary inflammations such as asthma or chronic obstructive pulmonary diseases (COPD) are likely to be infected with this virus. Of note, there is an argument that COVID-19 can remain with serious complications like fibrosis or other pathological changes in the pulmonary tissue of patients with chronic diseases. Along with conventional medications, regenerative medicine, and cell-based therapy could be alternative approaches to compensate for organ loss or restore injured sites using different stem cell types. Owing to unique differentiation capacity and paracrine activity, these cells can accelerate the healing procedure. In this review article, we have tried to scrutinize different reports related to the harmful effects of SARS-CoV-2 on patients with asthma and COPD, as well as the possible therapeutic effects of stem cells in the alleviation of post-COVID-19 complications. Video abstract.

CARM1 regulates senescence during airway epithelial cell injury in COPD pathogenesis.

Chronic obstructive pulmonary disease (COPD) is a life-threatening lung disease. Although cigarette smoke was considered the main cause of development, the heterogeneous nature of the disease leaves it unclear whether other factors contribute to the predisposition or impaired regeneration response observed. Recently, epigenetic modification has emerged to be a key player in the pathogenesis of COPD. The addition of methyl groups to arginine residues in both histone and nonhistone proteins by protein arginine methyltransferases (PRMTs) is an important posttranslational epigenetic modification event regulating cellular proliferation, differentiation, apoptosis, and senescence. Here, we hypothesize that coactivator-associated arginine methyltransferase-1 (CARM1) regulates airway epithelial cell injury in COPD pathogenesis by controlling cellular senescence. Using the naphthalene (NA)-induced mouse model of airway epithelial damage, we demonstrate that loss of CC10-positive club cells is accompanied by a reduction in CARM1-expressing cells of the airway epithelium. Furthermore, Carm1 haploinsuffficent mice showed perturbed club cell regeneration following NA treatment. In addition, CARM1 reduction led to decreased numbers of antisenescent sirtuin 1-expressing cells accompanied by higher p21, p16, and ß-galactosidase-positive senescent cells in the mouse airway following NA treatment. Importantly, CARM1-silenced human bronchial epithelial cells showed impaired wound healing and higher ß-galactosidase activity. These results demonstrate that CARM1 contributes to airway repair and regeneration by regulating airway epithelial cell senescence.

Impact of particulate air pollution on airway injury and epithelial plasticity; underlying mechanisms.

Air pollution plays an important role in the mortality and morbidity of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Particulate matter (PM) is a significant fraction of air pollutants, and studies have demonstrated that it can cause airway inflammation and injury. The airway epithelium forms the first barrier of defense against inhaled toxicants, such as PM. Airway epithelial cells clear airways from inhaled irritants and orchestrate the inflammatory response of airways to these irritants by secreting various lipid mediators, growth factors, chemokines, and cytokines. Studies suggest that PM plays an important role in the pathogenesis of chronic airway diseases by impairing mucociliary function, deteriorating epithelial barrier integrity, and inducing the production of inflammatory mediators while modulating the proliferation and death of airway epithelial cells. Furthermore, PM can modulate epithelial plasticity and airway remodeling, which play central roles in asthma and COPD. This review focuses on the effects of PM on airway injury and epithelial plasticity, and the underlying mechanisms involving mucociliary activity, epithelial barrier function, airway inflammation, epithelial-mesenchymal transition, mesenchymal-epithelial transition, and airway remodeling.

Issue 4 - Impact of air pollution on COVID-19 mortality and morbidity: An epidemiological and mechanistic review.

Air pollution is a major global environment and health concern. Recent studies have suggested an association between air pollution and COVID-19 mortality and morbidity. In this context, a close association between increased levels of air pollutants such as particulate matter ≤2.5 to 10 µM, ozone and nitrogen dioxide and SARS-CoV-2 infection, hospital admissions and mortality due to COVID 19 has been reported. Air pollutants can make individuals more susceptible to SARS-CoV-2 infection by inducing the expression of proteins such as angiotensin converting enzyme (ACE)2 and transmembrane protease, serine 2 (TMPRSS2) that are required for viral entry into the host cell, while causing impairment in the host defence system by damaging the epithelial barrier, muco-ciliary clearance, inhibiting the antiviral response and causing immune dysregulation. The aim of this review is to report the epidemiological evidence on impact of air pollutants on COVID 19 in an up-to-date manner, as well as to provide insights on in vivo and in vitro mechanisms.

The effect of multiple outgrowths from bronchial tissue explants on progenitor/stem cell number in primary bronchial epithelial cell cultures from smokers and patients with COPD.

Background: Although studies suggest a deficiency in stem cell numbers in chronic airway diseases such as chronic obstructive pulmonary disease (COPD), the role of bronchial epithelial progenitor/stem (P/S) cells is not clear. The objectives of this study were to investigate expression of progenitor/stem (P/S) cell markers, cytokeratin (CK) 5, CK14 and p63 in bronchial epithelial explants and cell cultures obtained from smokers with and without COPD following multiple outgrowths, and to study this effect on bronchial epithelial cell (BEC) proliferation. Methods: Bronchial epithelial explants were dissected from lung explants and cultured on coverslips. Confluent cultures were obtained after 3-4 weeks' (transfer, Tr1), explants were then transferred and cultured for a second (Tr2) and third (Tr3) time, respectively. At each stage, expression of CK5, CK14 and p63 in explants and BEC were determined by immunostaining. In parallel experiments, outgrowing cells from explants were counted after 4wks, and explants subsequently transferred to obtain new cultures for a further 3 times. Results: As the transfer number advanced, CK5, CK14 and p63 expression was decreased in both explants and BEC from both smokers without COPD and patients with COPD, with a more pronounced decrease in BEC numbers in the COPD group. Total cell numbers cultured from explants were decreased with advancing outgrowth number in both groups. Smoking status and lung function parameters were correlated with reduced P/S marker expression and cell numbers. Conclusion: Our findings suggest that the number of P/S cells in airway epithelium may play a role in the pathogenesis of COPD, as well as a role in the proliferation of airway epithelial cells, in vitro.

Emerging role of exosomes in the pathology of chronic obstructive pulmonary diseases; destructive and therapeutic properties.

Chronic obstructive pulmonary disease (COPD) is known as the third leading cause of human death globally. Enhanced chronic inflammation and pathological remodeling are the main consequences of COPD, leading to decreased life span. Histological and molecular investigations revealed that prominent immune cell infiltration and release of several cytokines contribute to progressive chronic remodeling. Recent investigations have revealed that exosomes belonging to extracellular vesicles are involved in the pathogenesis of COPD. It has been elucidated that exosomes secreted from immune cells are eligible to carry numerous pro-inflammatory factors exacerbating the pathological conditions. Here, in this review article, we have summarized various and reliable information about the negative role of immune cell-derived exosomes in the remodeling of pulmonary tissue and airways destruction in COPD patients.

The arginine methyltransferase PRMT7 promotes extravasation of monocytes resulting in tissue injury in COPD.

Extravasation of monocytes into tissue and to the site of injury is a fundamental immunological process, which requires rapid responses via post translational modifications (PTM) of proteins. Protein arginine methyltransferase 7 (PRMT7) is an epigenetic factor that has the capacity to mono-methylate histones on arginine residues. Here we show that in chronic obstructive pulmonary disease (COPD) patients, PRMT7 expression is elevated in the lung tissue and localized to the macrophages. In mouse models of COPD, lung fibrosis and skin injury, reduced expression of PRMT7 associates with decreased recruitment of monocytes to the site of injury and hence less severe symptoms. Mechanistically, activation of NF-κB/RelA in monocytes induces PRMT7 transcription and consequential mono-methylation of histones at the regulatory elements of RAP1A, which leads to increased transcription of this gene that is responsible for adhesion and migration of monocytes. Persistent monocyte-derived macrophage accumulation leads to ALOX5 over-expression and accumulation of its metabolite LTB4, which triggers expression of ACSL4 a ferroptosis promoting gene in lung epithelial cells. Conclusively, inhibition of arginine mono-methylation might offer targeted intervention in monocyte-driven inflammatory conditions that lead to extensive tissue damage if left untreated.

Existence of SARS-CoV-2 RNA on ambient particulate matter samples: A nationwide study in Turkey.

Coronavirus disease 2019 (COVID-19) is caused by the SARS-CoV-2 virus and has been affecting the world since the end of 2019. The disease led to significant mortality and morbidity in Turkey, since the first case was reported on March 11th, 2020. Studies suggest a positive association between air pollution and SARS-CoV-2 infection. The aim of the present study was to investigate the role of ambient particulate matters (PM), as potential carriers for SARS-CoV-2. Ambient PM samples in various size ranges were collected from 13 sites including urban and urban-background locations and hospital gardens in 10 cities across Turkey between 13th of May and 14th of June 2020 to investigate the possible presence of SARS-CoV-2 RNA on ambient PM. A total of 203 daily samples (TSP, n = 80; PM2.5, n = 33; PM2.5-10, n = 23; PM10µm, n = 19; and 6 size segregated PM, n = 48) were collected using various samplers. The N1 gene and RdRP gene expressions were analyzed for the presence of SARS-CoV-2, as suggested by the Centers for Disease Control and Prevention (CDC). According to real time (RT)-PCR and three-dimensional (3D) digital (d) PCR analysis, dual RdRP and N1 gene positivity were detected in 20 (9.8%) samples. Ambient PM-bound SARS-CoV-2 was analyzed quantitatively and the air concentrations of the virus ranged from 0.1 copies/m3 to 23 copies/m3. The highest percentages of virus detection on PM samples were from hospital gardens in Tekirdag, Zonguldak, and Istanbul, especially in PM2.5 mode. Findings of this study have suggested that SARS-CoV-2 may be transported by ambient particles, especially at sites close to the infection hot-spots. However, whether this has an impact on the spread of the virus infection remains to be determined.