Endoplasmic reticulum, Golgi, and lysosomes are disorganized in lung fibroblasts from chronic obstructive pulmonary disease patients

Understanding the impact of ER stress on lung physiology

Human lungs consist of a distinctive array of cell types, which are subjected to persistent challenges from chemical, mechanical, biological, immunological, and xenobiotic stress throughout life. The disruption of endoplasmic reticulum (ER) homeostatic function, triggered by various factors, can induce ER stress. To overcome the elevated ER stress, an adaptive mechanism known as the unfolded protein response (UPR) is activated in cells. However, persistent ER stress and maladaptive UPR can lead to defects in proteostasis at the cellular level and are typical features of the lung aging. The aging lung and associated lung diseases exhibit signs of ER stress-related disruption in cellular homeostasis. Dysfunction resulting from ER stress and maladaptive UPR can compromise various cellular and molecular processes associated with aging. Hence, comprehending the mechanisms of ER stress and UPR components implicated in aging and associated lung diseases could enable to develop appropriate therapeutic strategies for the vulnerable population.

Mechanisms and cross-talk of regulated cell death and their epigenetic modifications in tumor progression

Cell death is a fundamental part of life for metazoans. To maintain the balance between cell proliferation and metabolism of human bodies, a certain number of cells need to be removed regularly. Hence, the mechanisms of cell death have been preserved during the evolution of multicellular organisms. Tumorigenesis is closely related with exceptional inhibition of cell death. Mutations or defects in cell death-related genes block the elimination of abnormal cells and enhance the resistance of malignant cells to chemotherapy. Therefore, the investigation of cell death mechanisms enables the development of drugs that directly induce tumor cell death. In the guidelines updated by the Cell Death Nomenclature Committee (NCCD) in 2018, cell death was classified into 12 types according to morphological, biochemical and functional classification, including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, PARP-1 parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence and mitotic catastrophe. The mechanistic relationships between epigenetic controls and cell death in cancer progression were previously unclear. In this review, we will summarize the mechanisms of cell death pathways and corresponding epigenetic regulations. Also, we will explore the extensive interactions between these pathways and discuss the mechanisms of cell death in epigenetics which bring benefits to tumor therapy.

Altered hypoxia-induced cellular responses and inflammatory profile in lung fibroblasts from COPD patients compared to control subjects

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterized by chronic bronchitis, emphysema and vascular remodelling. The disease is associated with hypoxia, inflammation and oxidative stress. Lung fibroblasts are important cells in remodelling processes in COPD, as main producers of extracellular matrix proteins but also in synthesis of growth factors and inflammatory mediators.

METHODS

In this study we aimed to investigate if there are differences in how primary distal lung fibroblasts obtained from COPD patients and healthy subjects respond to hypoxia (1% O2) and pro-fibrotic stimuli with TGF-β1 (10 ng/mL). Genes and proteins associated with oxidative stress, endoplasmic reticulum stress, remodelling and inflammation were analysed with RT-qPCR and ELISA.

RESULTS

Hypoxia induced differences in expression of genes involved in oxidative stress (SOD3 and HIF-1α), ER stress (IRE1, PARK and ATF6), apoptosis (c-Jun and Bcl2) and remodelling (5HTR2B, Collagen7 and VEGFR2) in lung fibroblasts from COPD subjects compared to control subjects, where COPD fibroblasts were in general less responsive. The release of VEGF-C was increased after hypoxia, whereas TGF-β significantly reduced the VEGF response to hypoxia and the release of HGF. COPD fibroblasts had a higher release of IL-6, IL-8, MCP-1 and PGE2 compared to lung fibroblasts from control subjects. The release of inflammatory mediators was less affected by hypoxia, whereas TGFβ1 induced differences in inflammatory profile between fibroblasts from COPD and control subjects.

CONCLUSION

These results suggest that there is an alteration of gene regulation of various stress responses and remodelling associated mediator release that is related to COPD and hypoxia, where fibroblasts from COPD patients have a deficient response.

Cigarette Smoke Extract Induces MUC5AC Expression Through the ROS/ IP3R/Ca2+ Pathway in Calu-3 Cells

Background

Chronic obstructive pulmonary disease (COPD) is caused by exposure to noxious external particles, air pollution, and the inhalation of cigarette smoke. Airway mucus hypersecretion particularly mucin5AC (MUC5AC), is a crucial pathological feature of COPD and is associated with its initiation and progression. In this study, we aimed to investigate the effects of cigarette smoke extract (CSE) on MUC5AC expression, particularly the mechanisms by which reactive oxygen species (ROS) induce MUC5AC expression.

Methods

The effects of CSE on the expression of MUC5AC and mucin5B (MUC5B) were investigated in vitro in Calu-3 cells. MUC5AC and MUC5B expression levels were measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), immunofluorescence staining, and enzyme-linked immunosorbent assay (ELISA). Total cellular levels of ROS and Ca2+ were determined using DCFH-DA and Fluo-4 AM. Subsequently, the expression levels of IP3R, IRE1α, p-IRE1α and XBP1s were measured by Western blotting. Gene silencing was achieved by using small-interfering RNAs.

Results

Our findings revealed that exposure to CSE increased MUC5AC levels and upregulated ROS, IP3R/Ca2+ and unfolded protein response (UPR)-associated factors. In addition, knockdown of IP3R using siRNA decreased CSE-induced Ca2+ production, UPR-associated factors, and MUC5AC expression. Furthermore, 10 mM N-acetyl-l-cysteine (NAC) treatment suppressed the effects of CSE, including ROS generation, IP3R/ Ca2+, UPR activation, and MUC5AC overexpression.

Conclusion

Our results suggest that ROS regulates CSE-induced UPR and MUC5AC overexpression through IP3R/ Ca2+ signaling. Additionally, we identified NAC as a promising therapeutic agent for mitigating CSE-induced MUC5AC overexpression.

Expression of Stress-Induced Genes in Bronchoalveolar Lavage Cells and Lung Fibroblasts from Healthy and COPD Subjects

Chronic obstructive pulmonary disease (COPD) is commonly caused from smoking cigarettes that induce biological stress responses. Previously we found disorganized endoplasmic reticulum (ER) in fibroblasts from COPD with different responses to chemical stressors compared to healthy subjects. Here, we aimed to investigate differences in stress-related gene expressions within lung cells from COPD and healthy subjects. Bronchoalveolar lavage (BAL) cells were collected from seven COPD and 35 healthy subjects. Lung fibroblasts were derived from 19 COPD and 24 healthy subjects and exposed to cigarette smoke extract (CSE). Gene and protein expression and cell proliferation were investigated. Compared to healthy subjects, we found lower gene expression of CHOP in lung fibroblasts from COPD subjects. Exposure to CSE caused inhibition of lung fibroblast proliferation in both groups, though the changes in ER stress-related gene expressions (ATF6, IRE1, PERK, ATF4, CHOP, BCL2L1) and genes relating to proteasomal subunits mostly occurred in healthy lung fibroblasts. No differences were found in BAL cells. In this study, we have found that lung fibroblasts from COPD subjects have an atypical ER stress gene response to CSE, particularly in genes related to apoptosis. This difference in response to CSE may be a contributing factor to COPD progression.

Research trends on airway remodeling: A bibliometrics analysis

Background

Airway remodeling is an essential pathological basis of respiratory diseases such as asthma and COPD, which is significantly related to pulmonary function and clinical symptoms. And pulmonary disease can be improved by regulating airway remodeling. This study aimed to establish a knowledge map of airway remodeling to clarify current research hotspots and future research trends.

Methods

A comprehensive search was performed to analyze all relevant articles on airway remodeling using the Web of Science Core Collection Database from January 01, 2004 to June 03, 2023.2 reviewers screened the retrieved literature. Besides, the CiteSpace (6.2. R3) and VOSviewer (1.6.19) were utilized to visualize the research focus and trend regarding the effect of airway remodeling.

Results

A total of 4077 articles about airway remodeling were retrieved. The United States is the country with the most published literature, underscoring the country's role in airway remodeling. In recent years, China has been the country with the fastest growth in the number of published literature, suggesting that China will play a more critical role in airway remodeling in the future. From the perspective of co-operation among countries, European co-operation was closer than Asian co-operation. The co-citation analysis showed that 98,313 citations were recorded in 3594 articles, and 25 clusters could be realized. In recent years, Burst detection shows that oxidative stress and epithelial-mesenchymal transition are hot words.

Conclusions

Based on the bibliometric analysis of airway remodeling studies in the past 20 years, a multi-level knowledge structure map was drawn, it mainly includes countries, institutions, research fields, authors, journals, keywords and so on. The research directions represented by obstructive airway disease, PDGF-BB treatment of airway smooth muscle, allergen-induced airway remodeling, extracellular matrix, and non-coding RNA are the research hotspots in the field of airway remodeling. While the risk factors for airway remodeling, the application of new noninvasively assessing tools, biomarkers as well as The molecular mechanism represented by EMT and autophagy had been frontiers in recent years.

Combination of click chemistry and Schiff base reaction: Post-synthesis of covalent organic frameworks as an immobilized metal ion affinity chromatography platform for efficient capture of global phosphopeptides in serum with chronic obstructive pulmonary disease

Reasonable design and construction of functionalized materials are of great importance for the enrichment of global phosphopeptides. In this work, Ti4+ functionalized hydrophilic covalent organic frameworks by introducing glutathione (GSH) and 2,3,4-trihydroxy benzaldehyde (THBA) via click chemistry and Schiff base reaction (COF-V@GSH-THBA-Ti4+ ) was constructed and applied for selective enrichment of phosphopeptides in serum. Benefit from the high surface area, excellent hydrophilicity as well as regular mesoporous structure, COF-V@GSH-THBA-Ti4+ displayed high selectivity (molar ratio of 2000:1), low limit of detection (0.5 fmol), high load capacity (100.0 mg/g) and excellent size-exclusion effect (1:10000) for enrichment of phosphopeptides. For actual bio-sample analysis, 15 phosphopeptides assigned to 10 phosphoproteins with 16 phosphorylated sites and 33 phosphopeptides assigned to 25 phosphoproteins with 34 phosphorylated sites were detected from the serum of patients with chronic obstructive pulmonary disease (COPD), and normal controls. Biological processes and molecular functions analysis further disclosed the difference of serums with phosphoproteomics between COPD and normal controls.

Lung Fibroblasts from Chronic Obstructive Pulmonary Disease Subjects Have a Deficient Gene Expression Response to Cigarette Smoke Extract Compared to Healthy

Background and aim

Cigarette smoking is the most common cause of chronic obstructive pulmonary disease (COPD) but more mechanistic studies are needed. Cigarette smoke extract (CSE) can elicit a strong response in many COPD-related cell types, but no studies have been performed in lung fibroblasts. Therefore, we aimed to investigate the effect of CSE on gene expression in lung fibroblasts from healthy and COPD subjects.

Patients and methods

Primary lung fibroblasts, derived from six healthy and six COPD subjects (all current or ex-smokers), were either unstimulated (baseline) or stimulated with 30% CSE for 4 h prior to RNA isolation. The mRNA expression levels were measured using the NanoString nCounter Human Fibrosis V2 panel (760 genes). Pathway enrichment was assessed for unique gene ontology terms of healthy and COPD.

Results

At baseline, a difference in the expression of 17 genes was found in healthy and COPD subjects. Differential expression of genes after CSE stimulation resulted in significantly less changes in COPD lung fibroblasts (70 genes) than in healthy (207 genes), with 51 genes changed in both. COPD maintained low NOTCH signaling throughout and upregulated JUN >80%, indicating an increase in apoptosis. Healthy downregulated the Mitogen-activated protein kinase (MAPK) signaling cascade, including a ≥50% reduction in FGF2, CRK, TGFBR1 and MEF2A. Healthy also downregulated KAT6A and genes related to cell proliferation, all together indicating possible cell senescence signaling.

Conclusion

Overall, COPD lung fibroblasts responded to CSE stimulation with a very different and deficient expression profile compared to healthy. Highlighting that stimulated healthy cells are not an appropriate substitute for COPD cells which is important when investigating the mechanisms of COPD.

Cigarette smoke restricts the ability of mesenchymal cells to support lung epithelial organoid formation

Adequate lung epithelial repair relies on supportive interactions within the epithelial niche, including interactions with WNT-responsive fibroblasts. In fibroblasts from patients with chronic obstructive pulmonary disease (COPD) or upon in vitro cigarette smoke exposure, Wnt/β-catenin signalling is distorted, which may affect interactions between epithelial cells and fibroblasts resulting in inadequate lung repair. We hypothesized that cigarette smoke (CS), the main risk factor for COPD, interferes with Wnt/β-catenin signalling in fibroblasts through induction of cellular stress responses, including oxidative- and endoplasmic reticulum (ER) stress, and thereby alters epithelial repair support potential. Therefore, we assessed the effect of CS-exposure and the ER stress inducer Thapsigargin (Tg) on Wnt/β-catenin signalling activation in MRC-5 fibroblasts, and on their ability to support lung epithelial organoid formation. Exposure of MRC-5 cells for 15 min with 5 AU/mL CS extract (CSE), and subsequent 6 h incubation induced oxidative stress (HMOX1). Whereas stimulation with 100 nM Tg increased markers of both the integrated stress response (ISR - GADD34/PPP1R15A, CHOP) and the unfolded protein response (UPR - XBP1spl, GADD34/PPP1R15A, CHOP and HSPA5/BIP), CSE only induced GADD34/PPP1R15A expression. Strikingly, although treatment of MRC-5 cells with the Wnt activator CHIR99021 upregulated the Wnt/β-catenin target gene AXIN2, this response was diminished upon CSE or Tg pre-exposure, which was confirmed using a Wnt-reporter. Furthermore, pre-exposure of MRC-5 cells to CSE or Tg, restricted their ability to support organoid formation upon co-culture with murine pulmonary EpCam+ cells in Matrigel at day 14. This restriction was alleviated by pre-treatment with CHIR99021. We conclude that exposure of MRC-5 cells to CSE increases oxidative stress, GADD34/PPP1R15A expression and impairs their ability to support organoid formation. This inhibitory effect may be restored by activating the Wnt/β-catenin signalling pathway.

Endoplasmic reticulum stress: a vital process and potential therapeutic target in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a chronic and progressive disease characterized by persistent respiratory symptoms and progressive airflow obstruction, has attracted extensive attention due to its high morbidity and mortality. Although the understanding of the pathogenesis of COPD has gradually increased because of increasing evidence, many questions regarding the mechanisms involved in COPD progression and its deleterious effects remain unanswered. Recent advances have shown the potential functions of endoplasmic reticulum (ER) stress in causing airway inflammation, emphasizing the vital role of unfolded protein response (UPR) pathways in the development of COPD.

METHODS

A comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original research articles and reviews related to ER stress, UPR, and COPD.

RESULTS

The common causes of COPD, namely cigarette smoke (CS) and air pollutants, induce ER stress through the generation of reactive oxygen species (ROS). UPR promotes mucus secretion and further plays a dual role in the cell apoptosis-autophagy axis in the development of COPD. Existing drug research has indicated the potential of UPR as a therapeutic target for COPD.

CONCLUSIONS

ER stress and UPR activation play significant roles in the etiology, pathogenesis, and treatment of COPD and discuss whether related genes can be used as biomarkers and therapeutic targets.

Effects of hypoxia on bronchial and alveolar epithelial cells linked to pathogenesis in chronic lung disorders

Introduction: Chronic lung disorders involve pathological alterations in the lung tissue with hypoxia as a consequence. Hypoxia may influence the release of inflammatory mediators and growth factors including vascular endothelial growth factor (VEGF) and prostaglandin (PG)E2. The aim of this work was to investigate how hypoxia affects human lung epithelial cells in combination with profibrotic stimuli and its correlation to pathogenesis.

Methods: Human bronchial (BEAS-2B) and alveolar (hAELVi) epithelial cells were exposed to either hypoxia (1% O2) or normoxia (21% O2) during 24 h, with or without transforming growth factor (TGF)-β1. mRNA expression of genes and proteins related to disease pathology were analysed with qPCR, ELISA or immunocytochemistry. Alterations in cell viability and metabolic activity were determined.

Results: In BEAS-2B and hAELVi, hypoxia significantly dowregulated genes related to fibrosis, mitochondrial stress, oxidative stress, apoptosis and inflammation whereas VEGF receptor 2 increased. Hypoxia increased the expression of Tenascin-C, whereas both hypoxia and TGF-β1 stimuli increased the release of VEGF, IL-6, IL-8 and MCP-1 in BEAS-2B. In hAELVi, hypoxia reduced the release of fibroblast growth factor, epidermal growth factor, PGE2, IL-6 and IL-8, whereas TGF-β1 stimulus significantly increased the release of PGE2 and IL-6. TGF-β1 stimulated BEAS-2B cells showed a decreased release of VEGF-A and IL-8, while TGF-β1 stimulated hAELVi cells showed a decreased release of PGE2 and IL-8 during hypoxia compared to normoxia. Metabolic activity was significantly increased by hypoxia in both epithelial cell types.

Discussion: In conclusion, our data indicate that bronchial and alveolar epithelial cells respond differently to hypoxia and profibrotic stimuli. The bronchial epithelium appears more responsive to changes in oxygen levels and remodelling processes compared to the alveoli, suggesting that hypoxia may be a driver of pathogenesis in chronic lung disorders.

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.

A Pipeline for Natural Small Molecule Inhibitors of Endoplasmic Reticulum Stress

The homeostasis of eukaryotic cells is inseverable of that of the endoplasmic reticulum (ER). The main function of this organelle is the synthesis and folding of a significant portion of cellular proteins, while it is also the major calcium reservoir of the cell. Upon unresolved ER stress, a set of stress response signaling pathways that are collectively labeled as the unfolded protein response (UPR) is activated. Prolonged or intense activation of this molecular machinery may be deleterious. It is known that compromised ER homeostasis, and consequent UPR activation, characterizes the pathogenesis of neurodegenerative diseases. In an effort to discover new small molecules capable of countering ER stress, we subjected a panel of over 100 natural molecules to a battery of assays designed to evaluate several hallmarks of ER stress. The protective potential of these compounds against ER stress was evaluated at the levels of calcium homeostasis, key gene and protein expression, and levels of protein aggregation in fibroblasts. The most promising compounds were subsequently tested in neuronal cells. This framework resulted in the identification of several bioactive molecules capable of countering ER stress and deleterious events associated to it. Delphinidin stands out as the most promising candidate against neurodegeneration. This compound significantly inhibited the expression of UPR biomarkers, and displayed a strong potential to inhibit protein aggregation in the two aforementioned cell models. Our results indicate that natural products may be a valuable resource in the development of an effective therapeutic strategy against ER stress-related diseases.

Diseased lungs may hinder COVID-19 development: A possible reason for the low prevalence of COPD in COVID-19 patients

Presently, it remains unclear why the prevalence of lung diseases, namely chronic obstructive pulmonary disease (COPD), is much lower than other medical comorbidities and the general population among patients with coronavirus disease 2019 (COVID-19). If COVID-19 is a respiratory disease, why is COPD not the leading risk factor for contracting COVID-19? The same odd phenomenon was also observed with other pathogenic human coronaviruses causing severe acute respiratory distress syndrome (SARS) and Middle East respiratory syndrome (MERS), but not other respiratory viral infections such as influenza and respiratory syncytial viruses. One commonly proposed reason for the low COPD rates among COVID-19 patients is the usage of inhaled corticosteroids or bronchodilators that may protect against COVID-19. However, another possible reason not discussed elsewhere is that lungs in a diseased state may not be conducive for the severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) to establish COVID-19. For one, COPD causes mucous plugging in large and small airways, which may hinder SARS-CoV-2 from reaching deeper parts of the lungs (i.e., alveoli). Thus, SARS-CoV-2 may only localize to the upper respiratory tract of persons with COPD, causing mild or asymptomatic infections requiring no hospital attention. Even if SARS-CoV-2 reaches the alveoli, cells therein are probably under a heavy burden of endoplasmic reticulum (ER) stress and extensively damaged where it may not support efficient viral replication. As a result, limited SARS-CoV-2 virions would be produced in diseased lungs, preventing the development of COVID-19.

Human Lung Macrophages Challenged to Oxidants ex vivo: Lysosomal Membrane Sensitization is Associated with Inflammation and Chronic Airflow Limitation

Background

The lung macrophage (LM) is involved in most inflammatory processes of the human lung by clearance of dying cells and by wound repair. Upon cellular stress by oxidant challenge in vivo lysosomes may rupture in LMs and leakage of cellular content and cell debris may trigger airway inflammation and fibrosis, which may lead to chronic airflow limitation (CAL).

Objective

The aim of this study was to determine whether lysosomal membrane permeabilization (LMP) in LMs challenged to oxidants ex vivo is associated with airway inflammation and CAL, the latter assessed as the reduced forced expiratory volume in one second (FEV₁) expressed as % of predicted.

Materials and Methods

Twenty-eight subjects were investigated; 13 lung-healthy subjects and 15 subjects with a variety of inflammatory disorders, demonstrating CAL on dynamic spirometry (defined as an FEV₁/FVC ratio < 0.70). LMs were harvested by broncho-alveolar lavage (BAL) and challenged ex vivo by oxidants. LMP in oxidant-exposed LMs was assessed as the emitted acridine orange (AO) green fluorescence from oxidant-exposed LMs (using macrophage-like murine J774 cells as positive controls). Inflammatory cells in BAL were counted and lung volumes were recorded.

Results

Oxidant-induced LMP in LMs was significantly greater among subjects with CAL and particularly among those with ongoing inflammation. Previous tobacco history did not influence LMP. Among subjects with CAL, oxidant-induced LMP correlated negatively with FEV₁% of predicted.

Conclusion

Lysosomes of LMs harvested from patients with CAL demonstrate an increased sensitivity to oxidants, which may trigger mechanisms behind CAL, eg, chronic airway inflammation and fibrotic re-modelling. The study suggests a mechanistic role for LMP in LMs on airway inflammation, suggesting an anti-inflammatory effect by drugs that prevent increased LMP.

The ageing lung under stress

Healthy ageing of the lung involves structural changes but also numerous cell-intrinsic and cell-extrinsic alterations. Among them are the age-related decline in central cellular quality control mechanisms such as redox and protein homeostasis. In this review, we would like to provide a conceptual framework of how impaired stress responses in the ageing lung, as exemplified by dysfunctional redox and protein homeostasis, may contribute to onset and progression of COPD and idiopathic pulmonary fibrosis (IPF). We propose that age-related imbalanced redox and protein homeostasis acts, amongst others (e.g.cellular senescence), as a “first hit” that challenges the adaptive stress-response pathways of the cell, increases the level of oxidative stress and renders the lung susceptible to subsequent injury and disease. In both COPD and IPF, additional environmental insults such as smoking, air pollution and/or infections then serve as “second hits” which contribute to persistently elevated oxidative stress that overwhelms the already weakened adaptive defence and repair pathways in the elderly towards non-adaptive, irremediable stress thereby promoting development and progression of respiratory diseases. COPD and IPF are thus distinct horns of the same devil, “lung ageing”.

Cellular stress responses and dysfunctional Mitochondrial-cellular senescence, and therapeutics in chronic respiratory diseases

The abnormal inflammatory responses due to the lung tissue damage and ineffective repair/resolution in response to the inhaled toxicants result in the pathological changes associated with chronic respiratory diseases. Investigation of such pathophysiological mechanisms provides the opportunity to develop the molecular phenotype-specific diagnostic assays and could help in designing the personalized medicine-based therapeutic approaches against these prevalent diseases. As the central hubs of cell metabolism and energetics, mitochondria integrate cellular responses and interorganellar signaling pathways to maintain cellular and extracellular redox status and the cellular senescence that dictate the lung tissue responses. Specifically, as observed in chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis, the mitochondria-endoplasmic reticulum (ER) crosstalk is disrupted by the inhaled toxicants such as the combustible and emerging electronic nicotine-delivery system (ENDS) tobacco products. Thus, the recent research efforts have focused on understanding how the mitochondria-ER dysfunctions and oxidative stress responses can be targeted to improve inflammatory and cellular dysfunctions associated with these pathologic illnesses that are exacerbated by viral infections. The present review assesses the importance of these redox signaling and cellular senescence pathways that describe the role of mitochondria and ER on the development and function of lung epithelial responses, highlighting the cause and effect associations that reflect the disease pathogenesis and possible intervention strategies.

Respiratory Function and Dysfunction in Parkinson-Type Neurodegeneration

Parkinson's disease (PD) is most commonly manifested by the presence of motor symptoms. However, non-motor symptoms occur several years before the onset of motor symptoms themselves. Hallmarks of dysfunction of the respiratory system are still outside the main focus of interest, whether by clinicians or scientists, despite their indisputable contribution to the morbidity and mortality of patients suffering from PD. In addition, many of the respiratory symptoms are already present in the early stages of the disease and efforts to utilize these parameters in the early diagnosis of PD are now intensifying. Mechanisms that lead to the development and progression of respiratory symptoms are only partially understood. This review focuses mainly on the comparison of respiratory problems observed in clinical studies with available findings obtained from experimental animal models. It also explains pathological changes observed in non-neuronal tissues in subjects with PD.

Organelle-specific autophagy in inflammatory diseases: a potential therapeutic target underlying the quality control of multiple organelles

The structural integrity and functional stability of organelles are prerequisites for the viability and responsiveness of cells. Dysfunction of multiple organelles is critically involved in the pathogenesis and progression of various diseases, such as chronic obstructive pulmonary disease, cardiovascular diseases, infection, and neurodegenerative diseases. In fact, those organelles synchronously present with evident structural derangement and aberrant function under exposure to different stimuli, which might accelerate the corruption of cells. Therefore, the quality control of multiple organelles is of great importance in maintaining the survival and function of cells and could be a potential therapeutic target for human diseases. Organelle-specific autophagy is one of the major subtypes of autophagy, selectively targeting different organelles for quality control. This type of autophagy includes mitophagy, pexophagy, reticulophagy (endoplasmic reticulum), ribophagy, lysophagy, and nucleophagy. These kinds of organelle-specific autophagy are reported to be beneficial for inflammatory disorders by eliminating damaged organelles and maintaining homeostasis. In this review, we summarized the recent findings and mechanisms covering different kinds of organelle-specific autophagy, as well as their involvement in various diseases, aiming to arouse concern about the significance of the quality control of multiple organelles in the treatment of inflammatory diseases.Abbreviations: ABCD3: ATP binding cassette subfamily D member 3; AD: Alzheimer disease; ALS: amyotrophic lateral sclerosis; AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ARIH1: ariadne RBR E3 ubiquitin protein ligase 1; ATF: activating transcription factor; ATG: autophagy related; ATM: ATM serine/threonine kinase; BCL2: BCL2 apoptosis regulator; BCL2L11/BIM: BCL2 like 11; BCL2L13: BCL2 like 13; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; BNIP3L/NIX: BCL2 interacting protein 3 like; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CANX: calnexin; CAT: catalase; CCPG1: cell cycle progression 1; CHDH: choline dehydrogenase; COPD: chronic obstructive pulmonary disease; CSE: cigarette smoke exposure; CTSD: cathepsin D; DDIT3/CHOP: DNA-damage inducible transcript 3; DISC1: DISC1 scaffold protein; DNM1L/DRP1: dynamin 1 like; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; EIF2S1/eIF2α: eukaryotic translation initiation factor 2 alpha kinase 3; EMD: emerin; EPAS1/HIF-2α: endothelial PAS domain protein 1; ER: endoplasmic reticulum; ERAD: ER-associated degradation; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; FBXO27: F-box protein 27; FKBP8: FKBP prolyl isomerase 8; FTD: frontotemporal dementia; FUNDC1: FUN14 domain containing 1; G3BP1: G3BP stress granule assembly factor 1; GBA: glucocerebrosidase beta; HIF1A/HIF1: hypoxia inducible factor 1 subunit alpha; IMM: inner mitochondrial membrane; LCLAT1/ALCAT1: lysocardiolipin acyltransferase 1; LGALS3/Gal3: galectin 3; LIR: LC3-interacting region; LMNA: lamin A/C; LMNB1: lamin B1; LPS: lipopolysaccharide; MAPK8/JNK: mitogen-activated protein kinase 8; MAMs: mitochondria-associated membranes; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MFN1: mitofusin 1; MOD: multiple organelles dysfunction; MTPAP: mitochondrial poly(A) polymerase; MUL1: mitochondrial E3 ubiquitin protein ligase 1; NBR1: NBR1 autophagy cargo receptor; NLRP3: NLR family pyrin domain containing 3; NUFIP1: nuclear FMR1 interacting protein 1; OMM: outer mitochondrial membrane; OPTN: optineurin; PD: Parkinson disease; PARL: presenilin associated rhomboid like; PEX3: peroxisomal biogenesis factor 3; PGAM5: PGAM family member 5; PHB2: prohibitin 2; PINK1: PTEN induced putative kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RB1CC1/FIP200: RB1 inducible coiled-coil 1; RETREG1/FAM134B: reticulophagy regulator 1; RHOT1/MIRO1: ras homolog family member T1; RIPK3/RIP3: receptor interacting serine/threonine kinase 3; ROS: reactive oxygen species; RTN3: reticulon 3; SEC62: SEC62 homolog, preprotein translocation factor; SESN2: sestrin2; SIAH1: siah E3 ubiquitin protein ligase 1; SNCA: synuclein alpha; SNCAIP: synuclein alpha interacting protein; SQSTM1/p62: sequestosome 1; STING1: stimulator of interferon response cGAMP interactor 1; TAX1BP1: Tax1 binding protein 1; TBK1: TANK binding kinase 1; TFEB: transcription factor EB; TICAM1/TRIF: toll-like receptor adaptor molecule 1; TIMM23: translocase of inner mitochondrial membrane 23; TNKS: tankyrase; TOMM: translocase of the outer mitochondrial membrane; TRIM: tripartite motif containing; UCP2: uncoupling protein 2; ULK1: unc-51 like autophagy activating kinase; UPR: unfolded protein response; USP10: ubiquitin specific peptidase 10; VCP/p97: valosin containing protein; VDAC: voltage dependent anion channels; XIAP: X-linked inhibitor of apoptosis; ZNHIT3: zinc finger HIT-type containing 3.

PDIA4: The basic characteristics, functions and its potential connection with cancer

Disulfide bond formation is catalyzed by the protein disulfide Isomerases (PDI) family. This is a critical step in protein folding which occurs within the endoplasmic reticulum. PDIA4, as a member of the PDI family, can cause the adjustment of αIIβ 3 affinities which activate platelet and promote thrombosis formation. Endoplasmic reticulum response is triggered by accumulation of abnormal folding proteins concomitant with increasing PDIA4 expression. Besides, current researches indicate that activated platelets and ERS response affect tumor progression. And PDIA4, as previous reported, also participates in tumor progression by affecting cell apoptosis and DNA repair machinery without specific mechanisms revealed.Therefore, PDI inhibitor might possess great potential value in against tumor progression. In this review, we summarize information on PDIA4 including its the basic characteristics and its implication on tumor.

Accelerated lung aging and chronic obstructive pulmonary disease

INTRODUCTION

The prevalence of chronic obstructive pulmonary disease (COPD) increases exponentially with aging. Its pathogenesis, however, is not well known and aside from smoking cessation, there are no disease-modifying treatments for this disease. Areas covered: COPD is associated with accelerating aging and aging-related diseases. In this review, we will discuss the hallmarks of aging including genomic instability, telomere attrition, epigenetic alteration, loss of proteostasis, mitochondrial dysfunction, deregulated nutrient sensing, cellular senescence, stem cell exhaustion, and altered intercellular communication, which may be involved in COPD pathogenesis. Expert commentary: COPD and the aging process share similar molecular and cellular changes. Aging-related molecular pathways may represent novel therapeutic targets and biomarkers for COPD.