Epithelial-mesenchymal transition is driven by transcriptional and post transcriptional modulations in COPD: implications for disease progression and new therapeutics

Modulating versatile pathways using a cleavable PEG shell and EGFR-targeted nanoparticles to deliver CRISPR-Cas9 and docetaxel for triple-negative breast cancer inhibition

Human antigen R (HuR), an RNA-binding protein, is implicated in regulating mRNA stability and translation in cancer, especially in triple-negative breast cancer (TNBC), a highly aggressive form. CRISPR/Cas9-mediated HuR knockout (HuR CRISPR) presents a promising genetic therapeutic approach, but it encounters transfection limitations. Docetaxel (DTX), an effective cytotoxic agent against metastatic breast cancer (BC), faces challenges related to vehicle-associated adverse events in DTX formulations. Therefore, we designed multifunctional nanoparticles with pH-sensitive PEG derivatives and targeting peptides to enable efficient HuR CRISPR and DTX delivery to human TNBC MDA-MB-231 cells and tumor-bearing mice. Our findings indicated that these nanoparticles displayed pH-responsive cytotoxicity, precise EGFR targeting, efficient tumor penetration, successful endosomal escape, and accurate nuclear and cytoplasmic localization. They also demonstrated the ability to spare normal cells and prevent hemolysis. Our study concurrently modulated multiple pathways, including EGFR, Wnt/β-catenin, MDR, and EMT, through the regulation of EGFR/PI3K/AKT, HuR/galectin-3/GSK-3β/β-catenin, and P-gp/MRPs/BCRP, as well as YAP1/TGF-β/ZEB1/Slug/MMPs. The combined treatment arrested the cell cycle at the G2 phase and inhibited EMT, effectively impeding tumor progression. Tissue distribution, biochemical assays, and histological staining revealed the enhanced safety profile of pH-responsive PEG- and peptide-modified nanoformulations in TNBC mice. The DTX-embedded and peptide-modified nanoparticles mitigated the side effects of DTX, enhanced cytotoxicity in TNBC MDA-MB-231 cells, and exhibited remarkable antitumor efficacy and safety in TNBC-bearing mice with HuR CRISPR deletion. Collectively, the combination therapy of DTX and CRISPR/Cas9 offers an effective platform for delivering antineoplastic agents and gene-editing systems to combat tumor resistance and progression in TNBC.

MMPs as potential molecular targets in epithelial-to-mesenchymal transition driven COPD progression

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality globally and the risk of developing lung cancer is six times greater in individuals with COPD who smoke compared to those who do not smoke. Matrix metalloproteinases (MMPs) play a crucial role in the pathophysiology of respiratory diseases by promoting inflammation and tissue degradation. Furthermore, MMPs are involved in key processes like epithelial-to-mesenchymal transition (EMT), metastasis, and invasion in lung cancer. While EMT has traditionally been associated with the progression of lung cancer, recent research highlights its active involvement in individuals with COPD. Current evidence underscores its role in orchestrating airway remodeling, fostering airway fibrosis, and contributing to the potential for malignant transformation in the complex pathophysiology of COPD. The precise regulatory roles of diverse MMPs in steering EMT during COPD progression needs to be elucidated. Additionally, the less-understood aspect involves how these MMPs bi-directionally activate or regulate various EMT-associated signaling cascades during COPD progression. This review article explores recent advancements in understanding MMPs' role in EMT during COPD progression and various pharmacological approaches to target MMPs. It also delves into the limitations of current MMP inhibitors and explores novel, advanced strategies for inhibiting MMPs, potentially offering new avenues for treating respiratory diseases.

The Modulation of Respiratory Epithelial Cell Differentiation by the Thickness of an Electrospun Poly-ε-Carprolactone Mesh Mimicking the Basement Membrane

The topology of the basement membrane (BM) affects cell physiology and pathology, and BM thickening is associated with various chronic lung diseases. In addition, the topology of commercially available poly (ethylene terephthalate) (PET) membranes, which are used in preclinical in vitro models, differs from that of the human BM, which has a fibrous and elastic structure. In this study, we verified the effect of BM thickness on the differentiation of normal human bronchial epithelial (NHBE) cells. To evaluate whether the thickness of poly-ε-carprolactone (PCL) mesh affects the differentiation of NHBE cells, cells were grown on thin- (6-layer) and thick-layer (80-layer) meshes consisting of electrospun PCL nanofibers using an air-liquid interface (ALI) cell culture system. It was found that the NHBE cells formed a normal pseudostratified epithelium composed of ciliated, goblet, and basal cells on the thin-layer PCL mesh; however, goblet cell hyperplasia was observed on the thick-layer PCL mesh. Differentiated NHBE cells cultured on the thick-layer PCL mesh also demonstrated increased epithelial-mesenchymal transition (EMT) compared to those cultured on the thin-layer PCL mesh. In addition, expression of Sox9, nuclear factor (NF)-κB, and oxidative stress-related markers, which are also associated with goblet cell hyperplasia, was increased in the differentiated NHBE cells cultured on the thick-layer PCL mesh. Thus, the use of thick electrospun PCL mesh led to NHBE cells differentiating into hyperplastic goblet cells via EMT and the oxidative stress-related signaling pathway. Therefore, the topology of the BM, for example, thickness, may affect the differentiation direction of human bronchial epithelial cells.

The genomic landscape of chronic obstructive pulmonary disease: Insights from nutrigenomics

Chronic obstructivе pulmonary disеasе (COPD), a rеspiratory disеasе, is influenced by a combination of gеnеtic and еnvironmеntal factors. Thе fiеld of nutrigеnomics, which studiеs thе intеrplay bеtwееn diеt and gеnеs, provides valuable insights into thе gеnomic landscapе of COPD and its implications for production and managеmеnt. This rеviеw providеs a comprеhеnsivе ovеrviеw of thе gеnеtic aspеcts of COPD and thе rolе of nutrigеnomics in advancing our undеrstanding of thе undеrlying mеchanisms. Through studies of gеnomе-widе associations, researchers have identified gеnеtic factors that contribute to suscеptibility to COPD. Thеsе gеnеs arе associatеd with oxidativе strеss, inflammation, and antioxidant dеfеnsе mеchanisms. Nutrigеnomics rеsеarch is currеntly invеstigating how diеtary componеnts interact with gеnеtic variations to modulatе thе dеvеlopmеnt of COPD. Antioxidants, omеga-3 fatty acids and vitamin D havе dеmonstratеd potеntial bеnеfits in rеducing inflammation, improving lung function, and minimizing еxacеrbations in patients with COPD. Therefore, there are sеvеral challеngеs that must be added to the nutrigеnomic rеsеarch. The challenges include thе nееd for largеr clinical trials, adding hеtеrogеnеity and validating biomarkеrs. In the tеrms of futurе dirеctions, prеcision nutrition, gеnе-basеd thеrapiеs, biomarkеr dеvеlopmеnt, intеgration of multi-omics data, systеms biology analysis, longitudinal studiеs, and public hеalth implications arе important arеas to еxplorе. Pеrsonalizеd nutritional intеrvеntions based on an individual's gеnеtic profilе hold grеat promisе for optimizing COPD managеmеnt. In conclusion, nutrigеnomics provides valuable insights into the gеnomic landscapе of COPD and its intеraction with the disease. This knowlеdgе can guidе thе dеvеlopmеnt of pеrsonalizеd diеtary stratеgiеs and gеnе-basеd thеrapiеs for thе prеvеntion and managеmеnt of COPD. Howеvеr, morе rеsеarch is nееdеd to validatе thеsе findings, dеvеlop еffеctivе intеrvеntions, and implеmеnt thеm еffеctivеly in clinical practicе to improvе thе quality of lifе for pеoplе with COPD.

K63 Ubiquitination of P21 Can Facilitate Pellino-1 in the Context of Chronic Obstructive Pulmonary Disease and Lung Cellular Senescence

Chronic obstructive pulmonary diseases (COPD) is a kind of age-related, airflow-obstruction disease mostly caused by cigarette smoke. However, the relationship between COPD and lung cellular senescence is still not fully understood. Here, we found silencing Pellino-1 could inhibit the protein level of P21. Then, through constructing cell lines expressed ubiquitin-HA, we found that the E3 ubiquitin ligase Pellino-1 could bind to senescence marker p21 and modify p21 by K63-site ubiquitination by co-IP assays. Furthermore, we found that p21-mediated lung cellular senescence could be inhibited by silencing Pellino-1 in a D-galactose senescence mice model. Moreover, by constructing a COPD mouse model with shPellino-1 adenovirus, we found that silencing Pellino-1 could inhibit COPD and inflammation via reduction of SASPs regulated by p21. Taken together, our study findings elucidated that silencing E3 ligase Pellino-1 exhibits therapeutic potential for treatment to attenuate the progression of lung cellular senescence and COPD.

Extracellular Vesicles as Central Mediators of COPD Pathophysiology

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, smoking-related disease of significant global impact. The complex biology of COPD is ultimately driven by a few interrelated processes, including proteolytic tissue remodeling, innate immune inflammation, derangements of the host-pathogen response, aberrant cellular phenotype switching, and cellular senescence, among others. Each of these processes are engendered and perpetuated by cells modulating their environment or each other. Extracellular vesicles (EVs) are powerful effectors that allow cells to perform a diverse array of functions on both adjacent and distant tissues, and their pleiotropic nature is only beginning to be appreciated. As such, EVs are candidates to play major roles in these fundamental mechanisms of disease behind COPD. Furthermore, some such roles for EVs are already established, and EVs are implicated in significant aspects of COPD pathogenesis. Here, we discuss known and potential ways that EVs modulate the environment of their originating cells to contribute to the processes that underlie COPD.

Roles of Mesenchymal Cells in the Lung: From Lung Development to Chronic Obstructive Pulmonary Disease

Mesenchymal cells are an essential cell type because of their role in tissue support, their multilineage differentiation capacities and their potential clinical applications. They play a crucial role during lung development by interacting with airway epithelium, and also during lung regeneration and remodeling after injury. However, much less is known about their function in lung disease. In this review, we discuss the origins of mesenchymal cells during lung development, their crosstalk with the epithelium, and their role in lung diseases, particularly in chronic obstructive pulmonary disease.

C-EBPβ mediates in cigarette/IL-17A-induced bronchial epithelial-mesenchymal transition in COPD mice

BACKGROUND

Cigarettes smoking and IL-17A contribute to chronic obstructive pulmonary disease (COPD), and have synergistical effect on bronchial epithelial cell proliferation. CCAAT/enhancer-binding protein β (C-EBPβ) could be induced by IL-17A and is up-regulated in COPD. We explored the effect of cigarettes and IL-17 on bronchial epithelial-mesenchymal transition (EMT) in COPD mice and potential mechanism involved with C-EBPβ in this study.

METHODS

COPD model was established with mice by exposing to cigarettes. E-Cadherin, Vimentin, IL-17A and C-EBPβ distributions were detected in lung tissues. Primary bronchial epithelial cells were separated from health mice and cocultured with cigarette smoke extract (CSE) or/and IL-17A. E-Cadherin, Vimentin and IL-17 receptor (IL-17R) expressions in vitro were assessed. When C-EBPβ were silenced by siRNA in cells, E-Cadherin, Vimentin and C-EBPβ expressions were detected.

RESULTS

E-Cadherin distribution was less and Vimentin distribution was more in bronchus of COPD mice than controls. IL-17A and C-EBPβ expressions were higher in lung tissues of COPD mice than controls. In vitro, C-EBPβ protein expression was highest in CSE + IL-17A group, followed by CSE and IL-17A groups. E-cadherin expression in vitro was lowest and Vimentin expression was highest in CSE + IL-17A group, followed by CSE or IL-17A group. Those could be inhibited by C-EBPβ silenced.

CONCLUSIONS

C-EBPβ mediates in cigarette/IL-17A-induced bronchial EMT in COPD mice. Our findings contribute to a better understanding on the progress from COPD to lung cancers, which will provide novel avenues in preventing tumorigenesis of airway in the context of cigarette smoking.

Conditioned Media of Adipose-Derived Stem Cells Suppresses Sidestream Cigarette Smoke Extract Induced Cell Death and Epithelial-Mesenchymal Transition in Lung Epithelial Cells

The role of the epithelial-mesenchymal transition (EMT) in lung epithelial cells is increasingly being recognized as a key stage in the development of COPD, fibrosis, and lung cancers, which are all highly associated with cigarette smoking and with exposure to second-hand smoke. Using the exposure of human lung cancer epithelial A549 cells and non-cancerous Beas-2B cells to sidestream cigarette smoke extract (CSE) as a model, we studied the protective effects of adipose-derived stem cell-conditioned medium (ADSC-CM) against CSE-induced cell death and EMT. CSE dose-dependently induced cell death, decreased epithelial markers, and increased the expression of mesenchymal markers. Upstream regulator analysis of differentially expressed genes after CSE exposure revealed similar pathways as those observed in typical EMT induced by TGF-β1. CSE-induced cell death was clearly attenuated by ADSC-CM but not by other control media, such as a pass-through fraction of ADSC-CM or A549-CM. ADSC-CM effectively inhibited CSE-induced EMT and was able to reverse the gradual loss of epithelial marker expression associated with TGF-β1 treatment. CSE or TGF-β1 enhanced the speed of A549 migration by 2- to 3-fold, and ADSC-CM was effective in blocking the cell migration induced by either agent. Future work will build on the results of this in vitro study by defining the molecular mechanisms through which ADSC-CM protects lung epithelial cells from EMT induced by toxicants in second-hand smoke.

Recent advances in human respiratory epithelium models for drug discovery

The respiratory epithelium is intimately associated with the pathophysiologies of highly infectious viral contagions and chronic illnesses such as chronic obstructive pulmonary disorder, presently the third leading cause of death worldwide with a projected economic burden of £1.7 trillion by 2030. Preclinical studies of respiratory physiology have almost exclusively utilised non-humanised animal models, alongside reductionistic cell line-based models, and primary epithelial cell models cultured at an air-liquid interface (ALI). Despite their utility, these model systems have been limited by their poor correlation to the human condition. This has undermined the ability to identify novel therapeutics, evidenced by a 15% chance of success for medicinal respiratory compounds entering clinical trials in 2018. Consequently, preclinical studies require new translational efficacy models to address the problem of respiratory drug attrition. This review describes the utility of the current in vivo (rodent), ex vivo (isolated perfused lungs and precision cut lung slices), two-dimensional in vitro cell-line (A549, BEAS-2B, Calu-3) and three-dimensional in vitro ALI (gold-standard and co-culture) and organoid respiratory epithelium models. The limitations to the application of these model systems in drug discovery research are discussed, in addition to perspectives of the future innovations required to facilitate the next generation of human-relevant respiratory models.

Fully integrating pathophysiological insights in COPD: an updated working disease model to broaden therapeutic vision

Our starting point is that relatively new findings into the pathogenesis and pathophysiology of airway disease in smokers that lead to chronic obstructive pulmonary disease (COPD) need to be reassessed as a whole and integrated into "mainstream" thinking along with traditional concepts which have stood the test of time. Such a refining of the accepted disease paradigm is urgently needed as thinking on therapeutic targets is currently under active reconsideration. We feel that generalised airway wall "inflammation" is unduly over-emphasised, and highlight the patchy and variable nature of the pathology (with the core being airway remodelling). In addition, we present evidence for airway wall disease in smokers/COPD as including a hypocellular, hypovascular, destructive, fibrotic pathology, with a likely spectrum of epithelial-mesenchymal transition states as significant drivers of this remodelling. Furthermore, we present data from a number of research modalities and integrate this with the aetiology of lung cancer, the role of chronic airway luminal colonisation/infection by a specific group of "respiratory" bacteria in smokers (which results in luminal inflammation) and the central role for oxidative stress on the epithelium. We suggest translation of these insights into more focus on asymptomatic smokers and early COPD, with the potential for fresh preventive and therapeutic approaches.

Chronic Obstructive Pulmonary Disease: Epidemiology, Biomarkers, and Paving the Way to Lung Cancer

Chronic obstructive pulmonary disease (COPD), the frequently fatal pathology of the respiratory tract, accounts for half a billion cases globally. COPD manifests via chronic inflammatory response to irritants, frequently to tobacco smoke. The progression of COPD from early onset to advanced disease leads to the loss of the alveolar wall, pulmonary hypertension, and fibrosis of the respiratory epithelium. Here, we focus on the epidemiology, progression, and biomarkers of COPD with a particular connection to lung cancer. Dissecting the cellular and molecular players in the progression of the disease, we aim to shed light on the role of smoking, which is responsible for the disease, or at least for the more severe symptoms and worse patient outcomes. We summarize the inflammatory conditions, as well as the role of EMT and fibroblasts in establishing a cancer-prone microenvironment, i.e., the soil for ‘COPD-derived’ lung cancer. We highlight that the major health problem of COPD can be alleviated via smoking cessation, early diagnosis, and abandonment of the usage of biomass fuels on a global basis.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Downregulation of epithelial DUOX1 in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease characterized by small airway remodeling and alveolar emphysema due to environmental stresses such as cigarette smoking (CS). Oxidative stress is commonly implicated in COPD pathology, but recent findings suggest that one oxidant-producing NADPH oxidase homolog, dual oxidase 1 (DUOX1), is downregulated in the airways of patients with COPD. We evaluated lung tissue sections from patients with COPD for small airway epithelial DUOX1 protein expression, in association with measures of lung function and small airway and alveolar remodeling. We also addressed the impact of DUOX1 for lung tissue remodeling in mouse models of COPD. Small airway DUOX1 levels were decreased in advanced COPD and correlated with loss of lung function and markers of emphysema and remodeling. Similarly, DUOX1 downregulation in correlation with extracellular matrix remodeling was observed in a genetic model of COPD, transgenic SPC-TNF-α mice. Finally, development of subepithelial airway fibrosis in mice due to exposure to the CS-component acrolein, or alveolar emphysema induced by administration of elastase, were in both cases exacerbated in Duox1-deficient mice. Collectively, our studies highlight that downregulation of DUOX1 may be a contributing feature of COPD pathogenesis, likely related to impaired DUOX1-mediated innate injury responses involved in epithelial homeostasis.

Circ0061052 regulation of FoxC1/Snail pathway via miR-515-5p is involved in the epithelial-mesenchymal transition of epithelial cells during cigarette smoke-induced airway remodeling

Circular RNA (circRNA) has been shown to be widely involved in a variety of lung diseases. Cigarette smoke (CS) may induce epithelial-mesenchymal transition (EMT) of airway remodeling in chronic obstructive pulmonary disease (COPD), however, in which the roles and mechanisms of circRNA have not been elucidated. In this study, we aimed to determine whether circ0061052 is involved in the EMT of human bronchial epithelial (HBE) cells and its potential mechanism for playing a biological role. Cigarette smoke extract (CSE) caused elevated EMT indicators and the increases of circ0061052 in HBE cells. Circ0061052 has a ring structure and is mainly present in the cytoplasm of HBE cells. We analyzed the regulatory relationship between circ0061052 and miR-515-5p using bioinformatics, a luciferase reporter gene, and qRT-PCR. We found that circ0061052 is mainly distributed in the cytoplasm and competitively binds to miR-515-5p, acting as a sponge for miR-515-5p. The luciferase reporter gene showed that miR-515-5p binds to the 3'UTR region of FoxC1 mRNA to inhibit its transcription. For HBE cells, overexpression of miR-515-5p antagonized the CSE-induced EMT. In addition, circ0061052 acts by binding miR-515-5p competitively to regulate the expression of FoxC1/Snail. When circ0061052 siRNA and miR-515-5p inhibitor were co-transfected into HBE cells, the inhibitor reversed the effect of circ0061052 siRNA on reducing EMT. Chronic exposure of mice to CS induced increases of circ0061052 levels, decreases of miR-515-5p levels, and the EMT in lung tissue, which caused dysfunction and airway obstruction. Overall, the results show that, by regulating miR-515-5p through a FoxC1/Snail regulatory axis, circ0061052 is involved in the CS-induced EMT and airway remodeling in COPD.

Canonical WNT pathway is activated in the airway epithelium in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a devastating lung disease, mainly due to cigarette smoking, which represents the third cause of mortality worldwide. The mechanisms driving its epithelial salient features remain largely elusive. We aimed to evaluate the activation and the role of the canonical, β-catenin-dependant WNT pathway in the airway epithelium from COPD patients.

METHODS

The WNT/β-catenin pathway was first assessed by WNT-targeted RNA sequencing of the air/liquid interface-reconstituted bronchial epithelium from COPD and control patients. Airway expression of total and active β-catenin was assessed in lung sections, as well as WNT components in laser-microdissected airway epithelium. Finally, we evaluated the role of WNT at the bronchial epithelial level by modulating the pathway in the reconstituted COPD epithelium.

FINDINGS

We show that the WNT/β-catenin pathway is upregulated in the COPD airway epithelium as compared with that of non-smokers and control smokers, in targeted RNA-sequencing of in vitro reconstituted airway epithelium, and in situ in lung tissue and laser-microdissected epithelium. Extrinsic activation of this pathway in COPD-derived airway epithelium inhibited epithelial differentiation, polarity and barrier function, and induced TGF-β-related epithelial-to-mesenchymal transition (EMT). Conversely, canonical WNT inhibition increased ciliated cell numbers, epithelial polarity and barrier function, whilst inhibiting EMT, thus reversing COPD features.

INTERPRETATION

In conclusion, the aberrant reactivation of the canonical WNT pathway in the adult airway epithelium recapitulates the diseased phenotype observed in COPD patients, suggesting that this pathway or its downstream effectors could represent a future therapeutic target.

FUNDING

This study was supported by the Fondation Mont-Godinne, the FNRS and the WELBIO.

Effect of sub-chronic exposure to cigarette smoke, electronic cigarette and waterpipe on human lung epithelial barrier function

BACKGROUND

Taking into consideration a recent surge of a lung injury condition associated with electronic cigarette use, we devised an in vitro model of sub-chronic exposure of human bronchial epithelial cells (HBECs) in air-liquid interface, to determine deterioration of epithelial cell barrier from sub-chronic exposure to cigarette smoke (CS), e-cigarette aerosol (EC), and tobacco waterpipe exposures (TW).

METHODS

Products analyzed include commercially available e-liquid, with 0% or 1.2% concentration of nicotine, tobacco blend (shisha), and reference-grade cigarette (3R4F). In one set of experiments, HBECs were exposed to EC (0 and 1.2%), CS or control air for 10 days using 1 cigarette/day. In the second set of experiments, exposure of pseudostratified primary epithelial tissue to TW or control air exposure was performed 1-h/day, every other day, until 3 exposures were performed. After 16-18 h of last exposure, we investigated barrier function/structural integrity of the epithelial monolayer with fluorescein isothiocyanate-dextran flux assay (FITC-Dextran), measurements of trans-electrical epithelial resistance (TEER), assessment of the percentage of moving cilia, cilia beat frequency (CBF), cell motion, and quantification of E-cadherin gene expression by reverse-transcription quantitative polymerase chain reaction (RT-qPCR).

RESULTS

When compared to air control, CS increased fluorescence (FITC-Dextran assay) by 5.6 times, whereby CS and EC (1.2%) reduced TEER to 49 and 60% respectively. CS and EC (1.2%) exposure reduced CBF to 62 and 59%, and cilia moving to 47 and 52%, respectively, when compared to control air. CS and EC (1.2%) increased cell velocity compared to air control by 2.5 and 2.6 times, respectively. The expression of E-cadherin reduced to 39% of control air levels by CS exposure shows an insight into a plausible molecular mechanism. Altogether, EC (0%) and TW exposures resulted in more moderate decreases in epithelial integrity, while EC (1.2%) substantially decreased airway epithelial barrier function comparable with CS exposure.

CONCLUSIONS

The results support a toxic effect of sub-chronic exposure to EC (1.2%) as evident by disruption of the bronchial epithelial cell barrier integrity, whereas further research is needed to address the molecular mechanism of this observation as well as TW and EC (0%) toxicity in chronic exposures.

Cerebrovascular and Neurological Dysfunction under the Threat of COVID-19: Is There a Comorbid Role for Smoking and Vaping?

The recently discovered novel coronavirus, SARS-CoV-2 (COVID-19 virus), has brought the whole world to standstill with critical challenges, affecting both health and economic sectors worldwide. Although initially, this pandemic was associated with causing severe pulmonary and respiratory disorders, recent case studies reported the association of cerebrovascular-neurological dysfunction in COVID-19 patients, which is also life-threatening. Several SARS-CoV-2 positive case studies have been reported where there are mild or no symptoms of this virus. However, a selection of patients are suffering from large artery ischemic strokes. Although the pathophysiology of the SARS-CoV-2 virus affecting the cerebrovascular system has not been elucidated yet, researchers have identified several pathogenic mechanisms, including a role for the ACE2 receptor. Therefore, it is extremely crucial to identify the risk factors related to the progression and adverse outcome of cerebrovascular-neurological dysfunction in COVID-19 patients. Since many articles have reported the effect of smoking (tobacco and cannabis) and vaping in cerebrovascular and neurological systems, and considering that smokers are more prone to viral and bacterial infection compared to non-smokers, it is high time to explore the probable correlation of smoking in COVID-19 patients. Herein, we have reviewed the possible role of smoking and vaping on cerebrovascular and neurological dysfunction in COVID-19 patients, along with potential pathogenic mechanisms associated with it.

microRNAs Are Key Regulators in Chronic Lung Disease: Exploring the Vital Link between Disease Progression and Lung Cancer

microRNAs (miRNAs) bind to mRNAs and inhibit their expression through post-transcriptionally regulating gene expression. Here, we elaborate upon the concise summary of the role of miRNAs in carcinogenesis with specific attention to precursor respiratory pathogenesis caused by cigarette smoke modulation of these miRNAs. We review how miRNAs are implicated in cigarette-smoke-driven mechanisms, such as epithelial to mesenchymal transition, autophagy modulation, and lung ageing, which are important in the development of chronic obstructive pulmonary disease and potential progression to lung cancer. Extracellular vesicles are key to inter-cellular communication and sharing of miRNAs. A deeper understanding of the role of miRNAs in chronic respiratory disease and their use as clinical biomarkers has great potential. Therapeutic targeting of miRNAs may significantly benefit the prevention of cancer progression.