Protein Misfolding and Endoplasmic Reticulum Stress in Chronic Lung Disease: Will Cell-Specific Targeting Be the Key to the Cure?

Impact of electronic cigarettes (e-cigs) and heat-not-burn/heated tobacco products (HnB/HTP) on asthma and chronic obstructive pulmonary disease: a viewpoint of the Italian Society of Internal Medicine

The association of cigarette smoking with several severe and very severe diseases (oncological, cardiovascular, respiratory) which have dramatic epidemiological, medical, and financial impact, is a well-known public threat. Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent diseases in Italy, posing significant public health challenges. Tobacco smoking, a primary risk factor for COPD and a common asthma trigger, remains a critical preventable public health issue. While universally acknowledged that quitting smoking drastically reduces the risk of smoking-related health issues, a significant portion of smokers and patients find quitting challenging or undesirable, hence a need for new ways to deal with it. A worth considering alternative might be the switch to electronic cigarettes (e-cig), and heat-not-burn/heated tobacco products (HnB/HTP). Emerging evidence suggests potential benefits in asthma and COPD management when transitioning from traditional smoking to e-cigs or HnB devices. However, the effectiveness of these products in facilitating smoking cessation is still debated, alongside concerns about their role in promoting smoking initiation among non-smokers. Internists are among the physicians who most frequently assist patients with smoking-related diseases, and in this perspective they cannot avoid paying attention to the progressive diffusion of smoking products alternative to the traditional cigarette, and to the controversies with respect to their use. In this context, the Italian Society of Internal Medicine, also recognizing a growing need for clarity for healthcare providers, has undertaken a comprehensive analysis of existing literature to offer an informed perspective on the health impact of e-cigs and HnB/HTP on asthma and COPD.

A novel model for predicting prognosis in patients with idiopathic pulmonary fibrosis based on endoplasmic reticulum stress-related genes

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic disease of unknown pathogenic origin. Endoplasmic reticulum (ER) stress refers to the process by which cells take measures to ER function when the morphology and function of the reticulum are changed. Recent studies have demonstrated that the ER was involved in the evolution and progression of IPF. In this study, we obtained transcriptome data and relevant clinical information from the Gene Expression Omnibus database and conducted bioinformatics analysis. Among the 544 ER stress-related genes (ERSRGs), 78 were identified as differentially expressed genes (DEGs). These DEGs were primarily enriched in response to ER stress, protein binding, and protein processing. Two genes (HTRA2 and KTN1) were included for constructing an accurate molecular signature. The overall survival of patients was remarkably worse in the high-risk group than in the low-risk group. We further analyzed the difference in immune cells between high-risk and low-risk groups. M0 and M2 macrophages were significantly increased in the high-risk group. Our results suggested that ERSRGs might play a critical role in the development of IPF by regulating the immune microenvironment in the lungs, which provide new insights on predicting the prognosis of patients with IPF.

Identification of Genes Related to Endoplasmic Reticulum Stress (ERS) in Chronic Obstructive Pulmonary Disease (COPD) and Clinical Validation

Objective

Endoplasmic reticulum stress (ERS) is key in chronic obstructive pulmonary disease (COPD) incidence and progression. This study aims to identify potential ERS-related genes in COPD through bioinformatics analysis and clinical experiments.

Methods

We first obtained a COPD-related mRNA expression dataset (GSE38974) from the Gene Expression Omnibus (GEO) database. The R software was then used to identify potential differentially expressed genes (DEGs) of COPD-related ERS (COPDERS). Subsequently, the identified DEGs were subjected to protein-protein interaction (PPI), correlation, Gene Ontology (GO) enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Following that, qRT-PCR was used to examine the RNA expression of six ERS-related DEGs in blood samples obtained from the COPD and control groups. The genes were also subjected to microRNA analysis. Finally, a correlation analysis was performed between the DEGs and key clinical indicators.

Results

Six ERS-related DEGs (five upregulated and one downregulated) were identified based on samples drawn from 23 COPD patients and nine healthy individuals enrolled in the study. Enrichment analysis revealed multiple ERS-related pathways. The qRT-PCR and mRNA microarray bioinformatics analysis results showed consistent STC2, APAF1, BAX, and PTPN1 expressions in the COPD and control groups. Additionally, hsa-miR-485-5p was identified through microRNA prediction and DEG analysis. A correlation analysis between key genes and clinical indicators in COPD patients demonstrated that STC2 was positively and negatively correlated with eosinophil count (EOS) and lymphocyte count (LYM), respectively. On the other hand, PTPN1 showed a strong correlation with pulmonary function indicators.

Conclusion

Four COPDERS-related key genes (STC2, APAF1, BAX, and PTPN1) were identified through bioinformatics analysis and clinical validation, and the expressions of some genes exhibited a significant correlation with the selected clinical indicators. Furthermore, hsa-miR-485-5p was identified as a potential key target in COPDERS, but its precise mechanism remains unclear.

Meta-analysis of single-cell RNA-sequencing data for depicting the transcriptomic landscape of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by airflow limitation and chronic inflammation of the lungs that is a leading cause of death worldwide. Since the complete pathological mechanisms at the single-cell level are not fully understood yet, an integrative approach to characterizing the single-cell-resolution landscape of COPD is required. To identify the cell types and mechanisms associated with the development of COPD, we conducted a meta-analysis using three single-cell RNA-sequencing datasets of COPD. Among the 154,011 cells from 16 COPD patients and 18 healthy subjects, 17 distinct cell types were observed. Of the 17 cell types, monocytes, mast cells, and alveolar type 2 cells (AT2 cells) were found to be etiologically implicated in COPD based on genetic and transcriptomic features. The most transcriptomically diversified states of the three etiological cell types showed significant enrichment in immune/inflammatory responses (monocytes and mast cells) and/or mitochondrial dysfunction (monocytes and AT2 cells). We then identified three chemical candidates that may potentially induce COPD by modulating gene expression patterns in the three etiological cell types. Overall, our study suggests the single-cell level mechanisms underlying the pathogenesis of COPD and may provide information on toxic compounds that could be potential risk factors for COPD.

Soluble epoxide hydrolase deficiency attenuates airway inflammation in COPD via IRE1α/JNK/AP-1 signaling pathway

BACKGROUND

Soluble Epoxide Hydrolase (sEH) metabolizes anti-inflammatory epoxyeicosatrienoic acids and critically affects airway inflammation in chronic obstructive pulmonary disease (COPD). Considering the excessive endoplasmic reticulum stress is associated with the earlier onset of COPD. The role of sEH and endoplasmic reticulum stress in the pathogenesis of COPD remains unknown.

METHOD

16 weeks of cigarette-exposed mice were used to detect the relationship between sEH and endoplasmic reticulum stress in COPD. Human epithelial cells were used in vitro to determine the regulation mechanism of sEH in endoplasmic reticulum stress induced by cigarette smoke.

RESULTS

sEH deficiency helps reduce emphysema formation after smoke exposure by alleviating endoplasmic reticulum stress response. sEH deficiency effectively reverses the upregulation of phosphorylation IRE1α and JNK and the nuclear expression of AP-1, alleviating the secretion of inflammatory factors induced by cigarette smoke extract. Furthermore, the treatment with endoplasmic reticulum stress and IRE1α inhibitor downregulated cigarette smoke extract-induced sEH expression and the secretion of inflammatory factors.

CONCLUSION

sEH probably alleviates airway inflammatory response and endoplasmic reticulum stress via the IRE1α/JNK/AP-1 pathway, which might attenuate lung injury caused by long-term smoking and provide a new pharmacological target for preventing and treating COPD.

Relevance of serum levels of the endoplasmic reticulum stress protein GRP78 (glucose-regulated protein 78 kDa) as biomarker in pulmonary diseases

Cellular stress and inflammation contribute to the initiation and progression of a variety of pulmonary diseases. Endoplasmic reticulum (ER) stress and its main regulator GRP78 (glucose-regulated protein 78 kDa) appear to be involved in the pathogenesis of pulmonary diseases, and GRP78 was found to be a biomarker in a wide range of inflammatory diseases. The aim of this study was to investigate the relevance of serum GRP78 in pulmonary disorders.In this prospective cohort study, 78 consecutive patients with chronic obstructive pulmonary disease (COPD, n = 28), asthma (n = 38) or interstitial lung disease (ILD, n = 12) underwent measurement of serum GRP78 levels by ELISA.The mean age of patients was 59.8 ± 12.4 years, 48.7% were female. Patients with elevated GRP78 levels (> median) offered a significantly better oxygenation status (capillary pO2: 75.3 ± 11.7 mmHg vs. 67.8 ± 15.9 mmHg, p = 0.02). Significant correlations were observed between GRP78, on the one hand, and haemoglobin, high-sensitivity C-reactive protein (hs-CRP) and eosinophil counts, on the other hand (haemoglobin: Pearson's r = -0.25, hs-CRP: r = 0.30, eosinophils: r = 0.63).Subsequently, we evaluated GRP78 measurements in function of severity stratifiers of the specific underlying pulmonary disease. ILD patients with a severe diffusion impairment (DLCO< 40% of predicted), exhibited a significant decrease in GRP78 levels (p = 0.01). In COPD and asthma, both characterized by obstructive ventilatory defects, a forced expiratory volume in one second (FEV1) <30% of predicted was accompanied by significantly lower GRP78 (p = 0.0075).In both obstructive and restrictive pulmonary disorders, GRP78 protein concentrations were reduced with increasing disease severity. These data suggest a prevalent role of GRP78 in the presently studied pulmonary disorders.

Manganese-induced neuronal apoptosis: new insights into the role of endoplasmic reticulum stress in regulating autophagy-related proteins

Manganese (Mn) is an essential trace element that participates in various physiological and pathological processes. However, epidemiological observations indicate that overexposure to Mn is strongly associated with neurodegenerative disorders and has been recognized as a potential risk factor of neuronal apoptosis. Many mechanisms are involved in the pathogenesis of Mn-induced neuronal apoptosis, such as reactive oxygen species generation, neuroinflammation reactions, protein accumulation, endoplasmic reticulum stress (ER stress), and autophagy, all of which collectively accelerate the process of nerve cell damage. As sophisticated cellular processes for maintaining intracellular homeostasis, ER-mediated unfolded protein response and autophagy both play bilateral roles including cell protection and cell injury under pathophysiological conditions, which might interact with each other. Although emerging evidence suggests that ER stress is involved in regulating the compensatory activation of autophagy to promote cell survival, the inherent relationship between ER stress and autophagy on Mn-induced neurotoxicity remains obscure. Here, our review focuses on discussing the existing mechanisms and connections between ER stress, autophagy, and apoptosis, which provide a new perspective on Mn-induced neuronal apoptosis, and the pathogenesis of neurodegenerative diseases.

Role of ER Stress Mediated Unfolded Protein Responses and ER Stress Inhibitors in the Pathogenesis of Inflammatory Bowel Disease

Previous investigations have increased the knowledge about the pathological processes of inflammatory bowel diseases. Besides the complex organization of immune reactions, the mucosal epithelial lining has been recognized as a crucial regulator in the commencement and persistence of intestinal inflammation. As the intestinal epithelium is exposed to various environmental factors, the intestinal epithelial cells are confronted with diverse cellular stress conditions. In eukaryotic cells, an imbalance in the endoplasmic reticulum (ER) might cause aggregation of unfolded or misfolded proteins in the lumen of ER, a condition known as endoplasmic reticulum stress. This cellular mechanism stimulates the unfolded protein response (UPR), which elevates the potential of the endoplasmic reticulum protein folding, improves protein production and its maturation, and also stimulates ER-associated protein degradation. Current analyses reported that in the epithelium, the ER stress might cause the pathogenesis of inflammatory bowel disease that affects the synthesis of protein, inducing the apoptosis of the epithelial cell and stimulating the proinflammatory reactions in the gut. There have been significant efforts to develop small molecules or molecular chaperones that will be potent in ameliorating ER stress. The restoration of UPR balance in the endoplasmic reticulum via pharmacological intervention might be a novel therapeutic approach for the treatment of inflammatory bowel diseases (IBDs). This review provides novel insights into the role of chemical chaperone UPR modulators to modify ER stress levels. We further discuss the future directions/challenges in the development of therapeutic strategies for IBDs by targeting the ER stress. Figure depicting the role of endoplasmic reticulum stress-mediated inflammatory bowel disease and the therapeutic role of endoplasmic reticulum stress inhibitors in alleviating the diseased condition.

Endoplasmic Reticulum Stress in Chronic Obstructive Pulmonary Disease: Mechanisms and Future Perspectives

The endoplasmic reticulum (ER) is an integral organelle for maintaining protein homeostasis. Multiple factors can disrupt protein folding in the lumen of the ER, triggering ER stress and activating the unfolded protein response (UPR), which interrelates with various damage mechanisms, such as inflammation, apoptosis, and autophagy. Numerous studies have linked ER stress and UPR to the progression of chronic obstructive pulmonary disease (COPD). This review focuses on the mechanisms of other cellular processes triggered by UPR and summarizes drug intervention strategies targeting the UPR pathway in COPD to explore new therapeutic approaches and preventive measures for COPD.

The effects of epithelial-mesenchymal transitions in COPD induced by cigarette smoke: an update

Cigarette smoke is a complex aerosol containing a large number of compounds with a variety of toxicity and carcinogenicity. Long-term exposure to cigarette smoke significantly increases the risk of a variety of diseases, including chronic obstructive pulmonary disease (COPD) and lung cancer. Epithelial–mesenchymal transition (EMT) is a unique biological process, that refers to epithelial cells losing their polarity and transforming into mobile mesenchymal cells, playing a crucial role in organ development, fibrosis, and cancer progression. Numerous recent studies have shown that EMT is an important pathophysiological process involved in airway fibrosis, airway remodeling, and malignant transformation of COPD. In this review, we summarized the effects of cigarette smoke on the development and progression of COPD and focus on the specific changes and underlying mechanisms of EMT in COPD induced by cigarette smoke. We spotlighted the signaling pathways involved in EMT induced by cigarette smoke and summarize the current research and treatment approaches for EMT in COPD, aiming to provide ideas for potential new treatment and research directions.

Endoplasmic reticulum stress regulates pyroptosis in BPDE-induced BEAS-2B cells

Benzo(a)pyrene(B(a)P), as the main representative of polycyclic aromatic hydrocarbons, can promote inflammation and many chronic pulmonary diseases. However, the underlying mechanism of Benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE)-induced human bronchial epithelial cell pyroptosis related to endoplasmic reticulum stress (ERS) has not been elucidated. This study focused on the effects of BPDE on ERS and pyroptosis in human bronchial epithelial cells (BEAS-2B), and explored the relationship between ERS and pyroptosis. BEAS-2B cells were stimulated with 0.50, 0.75, and 1.00 μmol/L BPDE for 24 h to detect ERS and pyroptosis. After inhibition of ERS with 4-phenylbutyrate (4-PBA), pyroptosis of BEAS-2B cells was tested. The results showed that BPDE decreased the cell viability, changed the morphological structure of endoplasmic reticulum and increased the expression levels of GRP78 and p-PERK. After BPDE treatment, the cell membrane was damaged and incomplete under transmission electron microscope; Hoechst 33342/PI fluorescence staining showed that the number of PI-positive cells was enhanced. The expression levels of GSDMD-N, cleaved-caspase 1, and cleaved-IL-1β were elevated, and the expression levels of IL-1β, IL-18, and NLRP3 protein were improved. In BPDE combined with 4-PBA intervention group, the rate of PI-positive cells was reduced, the expression levels of GRP78, GSDMD-N, and cleaved-caspase 1 were decreased, and the expression levels of IL-1β, IL-18, and NLRP3 were decreased. In conclusion, BPDE could induce ERS and pyroptosis in BEAS-2B cells, and ERS may promote the occurrence of BPDE-induced pyroptosis.

Analysis of the association of ANO3/MUC15, COL4A4, RRBP1, and KLK1 polymorphisms with COPD susceptibility in the Kashi population

Objective

Chronic obstructive pulmonary disease (COPD) is a complex, multifactorial, polygenic disease. The rate of occurrence of COPD in the Kashi population (Uyghur) is significantly higher than that observed nationwide. The identification of COPD-related genes in the Chinese Uyghur population could provide useful insights that could help us understand this phenomenon. Our previous whole-exome sequencing study of three Uyghur families with COPD demonstrated that 72 mutations in 55 genes might be associated with COPD; these included rs15783G > A in the anoctamin 3 (ANO3) gene/mucin 15 (MUC15) gene, rs1800517G > A in the collagen type IV alpha 4 chain (COL4A4) gene, rs11960G > A in the ribosome binding protein 1 (RRBP1) gene, and rs5516C > G in the kallikrein 1 (KLK1) gene. This case–control study aimed to further validate the association of the four mutations with COPD in the Chinese Uyghur population.

Methods

Sanger sequencing was used for the genotyping of four polymorphisms (ANO3/MUC15 rs15783, COL4A4 rs1800517, RRBP1 rs11960, and KLK1 rs5516) in 541 unrelated Uyghur COPD patients and 534 Uyghur healthy controls. We then conducted stratified analyses based on the smoking status and airflow limitation severity, to explore the correlation between selected gene polymorphisms and COPD.

Results

ANO3/MUC15 rs15783 and KLK1 rs5516 polymorphisms could significantly reduce COPD risk (p < 0.05), but COL4A4 rs1800517 and RRBP1 rs11960 polymorphisms were not correlated with COPD in the entire population. In a stratified analysis of smoking status, non-smokers with the ANO3/MUC15 rs15783G/G genotype (OR = 0.63, p = 0.032) or COL4A4 rs1800517 allele G (OR = 0.80, p = 0.023) had a reduced risk of COPD. Smokers with the RRBP1 rs11960A/G genotype had a lower risk of COPD (OR = 0.41, p = 0.025). The KLK1 rs5516G > C polymorphism was associated with a decreased risk of COPD (OR < 1, p < 0.05), irrespective of the smoking status of individuals. No significant association with COPD severity was observed in individuals with these four polymorphisms (p > 0.05).

Conclusion

We identified four previously unreported mutations (ANO3/MUC15 rs15783, COL4A4 rs1800517, RRBP1 rs11960, and KLK1 rs5516) that might decrease the COPD risk in individuals with different smoking statuses in the Chinese Uyghur population. Our findings provide new light for the genetic risk factors associated with the occurrence of COPD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01975-3.

Endoplasmic Reticulum Stress: An Emerging Therapeutic Target for Intervertebral Disc Degeneration

Low back pain (LBP) is a global health issue. Intervertebral disc degeneration (IDD) is a major cause of LBP. Although the explicit mechanisms underpinning IDD are unclear, endoplasmic reticulum (ER) stress caused by aberrant unfolded or misfolded proteins may be involved. The accumulation of unfolded/misfolded proteins may result in reduced protein synthesis and promote aberrant protein degradation to recover ER function, a response termed the unfolded protein response. A growing body of literature has demonstrated the potential relationships between ER stress and the pathogenesis of IDD, indicating some promising therapeutic targets. In this review, we summarize the current knowledge regarding the impact of ER stress on the process of IDD, as well as some potential therapeutic strategies for alleviating disc degeneration by targeting different pathways to inhibit ER stress. This review will facilitate understanding the pathogenesis and progress of IDD and highlights potential therapeutic targets for treating this condition.

Tunicamycin Protects against LPS-Induced Lung Injury

The pulmonary endothelium is a dynamic semipermeable barrier that orchestrates tissue-fluid homeostasis; regulating physiological and immunological responses. Endothelial abnormalities are caused by inflammatory stimuli interacting with intracellular messengers to remodel cytoskeletal junctions and adhesion proteins. Those phenomena are associated with sepsis, acute lung injury, and acute respiratory distress syndrome. The molecular processes beyond those responses are the main interest of our group. Unfolded protein response (UPR) is a highly conserved molecular pathway resolving protein-folding defects to counteract cellular threats. An emerging body of evidence suggests that UPR is a promising target against lung and cardiovascular disease. In the present study, we reveal that Tunicamycin (TM) (UPR inducer) protects against lipopolysaccharide (LPS)-induced injury. The barrier function of the inflamed endothelium was evaluated in vitro (transendothelial and paracellular permeability); as well as in mice exposed to TM after LPS. Our study demonstrates that TM supports vascular barrier function by modulating actomyosin remodeling. Moreover, it reduces the internalization of vascular endothelial cadherin (VE-cadherin), enhancing endothelial integrity. We suggest that UPR activation may deliver novel therapeutic opportunities in diseases related to endothelial dysregulation.

Mouse Models of Lung Fibrosis

The drug discovery pipeline, from discovery of therapeutic targets through preclinical and clinical development phases, to an approved product by health authorities, is a time-consuming and costly process, where a lead candidates' success at reaching the final stage is rare. Although the time from discovery to final approval has been reduced over the last decade, there is still potential to further optimize and streamline the evaluation process of each candidate as it moves through the different development phases. In this book chapter, we describe our preclinical strategies and overall decision-making process designed to evaluate the tolerability and efficacy of therapeutic candidates suitable for patients diagnosed with fibrotic lung disease. We also describe the benefits of conducting preliminary discovery trials, to aid in the selection of suitable primary and secondary outcomes to be further evaluated and assessed in subsequent internal and external validation studies. We outline all relevant research methodologies and protocols routinely performed by our research group and hope that these strategies and protocols will be a useful guide for biomedical and translational researchers aiming to develop safe and beneficial therapies for patients with fibrotic lung disease.

Monocyte and macrophage derived myofibroblasts: Is it fate? A review of the current evidence

Since the discovery of the myofibroblast over 50 years ago, much has been learned about its role in wound healing and fibrosis. Its origin, however, remains controversial, with a number of progenitor cells being proposed. Macrophage-myofibroblast transition (MMT) is a recent term coined in 2014 that describes the mechanism through which macrophages, derived from circulating monocytes originating in the bone marrow, transformed into myofibroblasts and contributed to kidney fibrosis. Over the past years, several studies have confirmed the existence of MMT in various systems, suggesting that MMT could potentially occur in all fibrotic conditions and constitute a reasonable therapeutic target to prevent progressive fibrotic disease. In this perspective, we examined recent evidence supporting the notion of MMT in both human disease and experimental models across organ systems. Mechanistic insight from these studies and information from in vitro studies is provided. The findings substantiating plausible MMT showcased the co-expression of macrophage and myofibroblast markers, including CD68 or F4/80 (macrophage) and α-SMA (myofibroblast), in fibroblast-like cells. Furthermore, fate-mapping experiments in murine models exhibiting myeloid-derived myofibroblasts in the tissue further provide direct evidence for MMT. Additionally, we provide some evidence from single cell RNA sequencing experiments confirmed by fluorescent in situ hybridisation studies, showing monocyte/macrophage and myofibroblast markers co-expressed in lung tissue from patients with fibrotic lung disease. In conclusion, MMT is likely a significant contributor to myofibroblast formation in wound healing and fibrotic disease across organ systems. Circulating precursors including monocytes and the molecular mechanisms governing MMT could constitute valid targets and provide insight for the development of novel antifibrotic therapies; however, further understanding of these processes is warranted.

Targeting COVID-19 in Parkinson's Patients: Drugs Repurposed

The last couple of months have witnessed the world in a state of virtual standstill. The SARS-CoV-2 virus has overtaken the globe to economic and social lockdown. Many patients with COVID-19 have compromised immunity, especially in an aged population suffering from Parkinson 's disease (PD). Alteration in dopaminergic neurons and deficiency of dopamine in PD patients are the most common symptoms affecting 1% population above the age of 60 years. The compromised immune system and inflammatory manifestation in PD patients make them an easy target. The most common drugs under trial for COVID-19 are remdesivir, favipiravir, chloroquine and hydroxychloroquine, azithromycin along with adjunct drugs like amantadine with some monoclonal antibodies. Presently, clinically US FDA approved drugs in PD include Levodopa, catechol-O-methyl transferase (COMT) inhibitors, (Entacapone and Tolcapone), dopamine agonists (Bromocriptine, Ropinirole, Pramipexole, and Rotigotine), monoamine oxidase B (MAO-B) inhibitors (Selegiline and Rasagiline), amantadine and antimuscarinic drugs. The drugs have established mechanisms of action on PD patients with known pharmacodynamics and pharmacokinetic properties along with dose and adverse effects. Conclusion and relevance of this review focus on the drugs that can be tried on PD patients with SAR CoV-2 infection, in particular, amantadine that has been approved by all the developed countries as a common drug possessing both antiviral properties by downregulation of CTSL, lysosomal pathway disturbance and change in pH necessary to uncoat the viral proteins and anti- Parkinson properties. To deal with the significant prognostic adverse effect of SARS-CoV-2 on PD, the present-day treatment options, clinical presentation and various mechanisms are the need of the hour.

A new horizon for the old antibacterial drug clofoctol

The synthetic antibacterial drug clofoctol (CFT) has long been used to treat respiratory tract infections in Europe. In recent years, the drug was found to target two biologically important proteins, the Cdc7/Dbf4 protein kinase complex and the mRNA-binding protein cold shock domain containing E1 (CSDE1), also known as upstream-of-N-Ras protein (UNR). These interactions are at the origin of the antitumor activity of CFT, recently evidenced in prostate cancer and neuroglioma. Drug-protein binding models provide a structural basis to guide the design of more potent anticancer compounds. A renewed interest in CFT can be anticipated for the treatment of cancers, and possibly Coronavirus 2019 (COVID-19).

Rcn3 Suppression Was Responsible for Partial Relief of Emphysema as Shown by Specific Type II Alveolar Epithelial Cell Rcn3 CKO Mouse Model

Background

Chronic obstructive pulmonary disease (COPD), characterized by irreversible airflow limitation, is a highly prevalent lung disease worldwide and imposes increasing disease burdens globally. Emphysema is one of the primary pathological features contributing to the irreversible decline of pulmonary function in COPD patients, but the pathogenetic mechanisms remain unclear. Reticulocalbin 3 (Rcn3) is an endoplasmic reticulum (ER) lumen protein localized in the secretory pathway of living cells. Rcn3 in type II alveolar epithelial cell (AECIIs) has been reported to play a critical role in regulating perinatal lung development and bleomycin-induced lung injury-repair processes. We hypothesized that Rcn3 deficiency is associated with the development of emphysema during COPD, which is associated with the dysfunction of injury-repair modulated by alveolar epithelial cells.

Materials and Methods

We examined Rcn3 expression in lung specimens from COPD patients and non-COPD control patients undergoing lung lobectomy or pneumonectomy. Two mouse models of emphysema were established by cigarette smoke (CS) exposure and intratracheal instillation of porcine pancreatic elastase (PPE). Rcn3 expression was detected in the lung tissues from these mice. Furthermore, conditional knockout (CKO) mice with Rcn3 deletion specific to AECIIs were used to explore the role of Rcn3 in PPE-induced emphysema progression. Rcn3 protein expression in lung tissues was evaluated by Western blot and immunohistochemistry. Rcn3 mRNA expression in lung tissues was detected by qPCR.

Results

Rcn3 expression was significantly increased in the lung specimens from COPD patients versus non-COPD patients and the level of Rcn3 increase was associated with the degree of emphysema. Rcn3 expression were also significantly up-regulated in both CS-induced and PPE-induced emphysematous mouse lungs. Moreover, the selective ablation of Rcn3 in AECIIs significantly alleviated severity of the mouse emphysema in response to intratracheal installation of PPE.

Conclusion

Our data, for the first time, indicated that suppression of Rcn3 expression in AECIIs has a beneficial effect on PPE-induced emphysema.

Effect of pH and urea on the proteins secondary structure at the water/air interface and in solution

HYPOTHESIS

The secondary structure of proteins affects their functionality and performance in physiological environments or industrial applications. Change of the solution pH or the presence of protein denaturants are the main chemical means that can alter the secondary structure of proteins or lead to protein denaturation. Since proteins in the bulk solution and those residing at the solution/air interface experience different local environments, their response to chemical denaturation can be different.

EXPERIMENTS

We utilize circular dichroism and chiral/achiral sum frequency generation spectroscopy to study the secondary structure of selected proteins as a function of the solution pH or in the presence of 8 M urea in the bulk solution and at the solution/air interface, respectively.

FINDINGS

The liquid/air interface can enhance or decrease protein conformation stability. The change in the secondary structure of the surface adsorbed proteins in alkaline solutions occurs at pH values lower than those denaturing the studied proteins in the bulk solution. In contrast, while 8 M urea completely denatures the studied proteins in the bulk solution, the liquid/air interface prevents the urea-induced denaturation of the surface adsorbed proteins by limiting the access of urea to the hydrophobic side chains of proteins protruding to air.

The ER Stress/UPR Axis in Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis

Cellular protein homeostasis in the lungs is constantly disrupted by recurrent exposure to various external and internal stressors, which may cause considerable protein secretion pressure on the endoplasmic reticulum (ER), resulting in the survival and differentiation of these cell types to meet the increased functional demands. Cells are able to induce a highly conserved adaptive mechanism, known as the unfolded protein response (UPR), to manage such stresses. UPR dysregulation and ER stress are involved in numerous human illnesses, such as metabolic syndrome, fibrotic diseases, and neurodegeneration, and cancer. Therefore, effective and specific compounds targeting the UPR pathway are being considered as potential therapies. This review focuses on the impact of both external and internal stressors on the ER in idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) and discusses the role of the UPR signaling pathway activation in the control of cellular damage and specifically highlights the potential involvement of non-coding RNAs in COPD. Summaries of pathogenic mechanisms associated with the ER stress/UPR axis contributing to IPF and COPD, and promising pharmacological intervention strategies, are also presented.

Hyperoxia induces endoplasmic reticulum stress‑associated apoptosis via the IRE1&alpha; pathway in rats with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in premature infants, and alveolar dysplasia and pulmonary vascular development disorders are the predominant pathological features. Apoptosis of lung epithelial cells is a key factor in the pathological process of alveolar developmental arrest. Endoplasmic reticulum stress (ERS)-associated apoptosis is a noncanonical apoptotic pathway involved in the development of several pulmonary diseases. Previous studies have demonstrated that protein kinase RNA-like endoplasmic reticulum kinase, inositol-requiring enzyme 1α (IRE1α) and activating transcription factor 6 can initiate the apoptosis signaling pathway mediated by ERS and induce apoptosis of injured cells. Among them, the IRE1α pathway is the most conservative pathway in the unfolded protein response, which serves an important role in a number of pathological environments, to the extent of determining cell fate; however, it is rarely reported in BPD. Based on the establishment of a rat BPD model, the present study verified the activation of ERS in BPD and further confirmed that prolonged ERS inhibited the protective pathway, IRE1α/X-box binding proteins, and activated the proapoptotic pathway, IRE1α/c-Jun N-terminal kinase, to induce the apoptosis of lung epitheliums.

Formation of lamellar body-like structure may be an initiator of didecyldimethylammonium chloride-induced toxic response

Due to the pandemic of coronavirus disease 2019, the use of disinfectants is rapidly increasing worldwide. Didecyldimethylammonium chloride (DDAC) is an EPA-registered disinfectant, it was also a component in humidifier disinfectants that had caused idiopathic pulmonary diseases in Korea. In this study, we identified the possible pulmonary toxic response and mechanism using human bronchial epithelial (BEAS-2B) cells and mice. First, cell viability decreased sharply at a 4 μg/mL of concentration. The volume of intracellular organelles and the ROS level reduced, leading to the formation of apoptotic bodies and an increase of the LDH release. Secretion of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and matrix metalloproteinase-1 also significantly increased. More importantly, lamellar body-like structures were formed in both the cells and mice exposed to DDAC, and the expression of both the indicator proteins for lamellar body (ABCA3 and Rab11a) and surfactant proteins (A, B, and D) was clearly enhanced. In addition, chronic fibrotic pulmonary lesions were notably observed in mice instilled twice (weekly) with DDAC (500 μg), ultimately resulting in death. Taken together, we suggest that disruption of pulmonary surfactant homeostasis may contribute to DDAC-induced cell death and subsequent pathophysiology and that the formation of lamellar body-like structures may play a role as the trigger. In addition, we propose that the cause of sudden death of mice exposed to DDAC should be clearly elucidated for the safe application of DDAC.