Extracellular Hsp70 modulates the inflammatory response of cigarette smoke extract in NCI-H292 cells

An integral perspective of canonical cigarette and e-cigarette-related cardiovascular toxicity based on the adverse outcome pathway framework

BACKGROUND

Nowadays, cigarette smoking remains the leading cause of chronic disease and premature death, especially cardiovascular disease. As an emerging tobacco product, e-cigarettes have been advocated as alternatives to canonical cigarettes, and thus may be an aid to promote smoking cessation. However, recent studies indicated that e-cigarettes should not be completely harmless to the cardiovascular system.

AIM OF REVIEW

This review aimed to build up an integral perspective of cigarettes and e-cigarettes-related cardiovascular toxicity.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review adopted the adverse outcome pathway (AOP) framework as a pivotal tool and aimed to elucidate the association between the molecular initiating events (MIEs) induced by cigarette and e-cigarette exposure to the cardiovascular adverse outcome. Since the excessive generation of reactive oxygen species (ROS) has been widely approved to play a critical role in cigarette smoke-related CVD and may also be involved in e-cigarette-induced toxic effects, the ROS overproduction and subsequent oxidative stress are regarded as essential parts of this framework. As far as we know, this should be the first AOP framework focusing on cigarette and e-cigarette-related cardiovascular toxicity, and we hope our work to be a guide in exploring the biomarkers and novel therapies for cardiovascular injury.

The Role of Epithelial Damage in the Pulmonary Immune Response

Pulmonary epithelial cells are widely considered to be the first line of defence in the lung and are responsible for coordinating the innate immune response to injury and subsequent repair. Consequently, epithelial cells communicate with multiple cell types including immune cells and fibroblasts to promote acute inflammation and normal wound healing in response to damage. However, aberrant epithelial cell death and damage are hallmarks of pulmonary disease, with necrotic cell death and cellular senescence contributing to disease pathogenesis in numerous respiratory diseases such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and coronavirus disease (COVID)-19. In this review, we summarise the literature that demonstrates that epithelial damage plays a pivotal role in the dysregulation of the immune response leading to tissue destruction and abnormal remodelling in several chronic diseases. Specifically, we highlight the role of epithelial-derived damage-associated molecular patterns (DAMPs) and senescence in shaping the immune response and assess their contribution to inflammatory and fibrotic signalling pathways in the lung.

XIST promotes apoptosis and the inflammatory response in CSE-stimulated cells via the miR-200c-3p/EGR3 axis

Background

Chronic obstructive pulmonary disease (COPD) is a disease that causes obstructed airways and abnormal inflammatory responses in the lungs. Early growth response 3 (EGR3) has been revealed to play a vital role in the regulation of the inflammatory response in certain diseases. We aimed to explore the role of EGR3 and its upstream mechanism in COPD.

Methods and result

In the present study, 16HBE cells were treated with cigarette smoke extract (CSE) to mimic the inflammatory response in vitro. RT-qPCR revealed that the expression of EGR3 was upregulated in lungs from COPD patients. EGR3 expression in 16HBE cells was increased by CSE treatment. Moreover, flow cytometry analysis and western blot analysis showed that EGR3 downregulation inhibited 16HBE cell apoptosis. EGR3 silencing decreased the protein levels of IL-6, TNF-α, IL-1β and COX2 in CSE-stimulated 16HBE cells. In addition, EGR3 was targeted by microRNA-200c-3p (miR-200c-3p) in 16HBE cells. MiR-200c-3p expression was significantly decreased in lung tissues from COPD patients compared to that in healthy controls. Furthermore, miR-200c-3p bound to lncRNA X-inactive specific transcript (XIST) in 16HBE cells. Additionally, XIST expression was elevated in lung tissues from COPD patients. Rescue assays indicated that EGR3 overexpression counteracted the effects of XIST downregulation on apoptosis and inflammation in CSE-stimulated 16HBE cells.

Conclusion

The XIST/miR-200c-3p/EGR3 axis facilitated apoptosis and inflammation in CSE-stimulated 16HBE cells. These findings may provide novel insight for treating COPD by alleviating lung inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01582-8.

Secreted heat shock proteins control airway remodeling: Evidence from bronchial thermoplasty

BACKGROUND

Increased airway smooth muscle mass is a key pathology in asthma. Bronchial thermoplasty is a treatment for severe asthma based on selective heating of the airways that aims to reduce the mass of airway smooth muscle cells (ASMCs), and thereby bronchoconstriction. However, short heat exposure is insufficient to explain the long-lasting effect, and heat shock proteins (HSPs) have been suggested to play a role.

OBJECTIVE

We sought to determine the role of HSP70 and HSP90 in the control of airway wall remodeling by bronchial thermoplasty.

METHODS

Bronchoalveolar lavage fluid and endobronchial biopsies of 20 patients with severe asthma were obtained before and after thermoplasty. Isolated epithelial cells and ASMCs were exposed to 65^oC for 10 seconds, mimicking thermoplasty. Proteins were determined by immunohistochemistry, Western blotting, immunofluorescence, and ELISA; proliferation by cell counts and antigen Ki67 (MKI67) expression.

RESULTS

Thermoplasty significantly increased the expression of HSP70 and HSP90 in the epithelium and bronchoalveolar lavage fluid. In ASMCs, thermoplasty reduced both HSPs. These cell-type-specific effects were detectable even 1 month after thermoplasty in tissue sections. In epithelial cells, ex vivo exposure to heat (65^oC, 10 seconds) increased the expression and secretion of HSP70 and HSP90. In addition, epithelial cell proliferation was upregulated by heat or treatment with human recombinant HSP70 or HSP90. In ASMCs, heat exposure or exogenous HSPs reduced proliferation and differentiation. In both cell types, HSP70 and HSP90 activated the signaling cascade of serine/threonine-protein kinase →mammalian target of rapamycin→ribosomal protein S6 kinase 1 and CCAAT/enhancer binding protein-β→protein arginine methyltransferase 1→ mitochondria activity.

CONCLUSIONS

Epithelial cell-derived HSP70 and HSP90 improve the function of epithelial cells, but block ASMC remodeling.

Structure, gene expression, and putative functions of crustacean heat shock proteins in innate immunity

Heat shock proteins (HSPs) are molecular chaperones with critical roles in the maintenance of cellular proteostasis. HSPs, which regulate protein folding and refolding, assembly, translocation, and degradation, are induced in response to physiological and environmental stressors. In recent years, HSPs have been recognized for their potential role in immunity; in particular, these proteins elicit a variety of immune responses to infection and modulate inflammation. This review focuses on delineating the structural and functional roles of crustacean HSPs in the innate immune response. Members of crustacean HSPs include high molecular weight HSPs (HSP90, HSP70, and HSP60) and small molecular weight HSPs (HSP21 and HSP10). The sequences and structures of these HSPs are highly conserved across various crustacean species, indicating strong evolutionary links among this group of organisms. The expression of HSP-encoding genes across different crustacean species is significantly upregulated upon exposure to a wide range of pathogens, emphasizing the important role of HSPs in the immune response. Functional studies of crustacean HSPs, particularly HSP70s, have demonstrated their involvement in the activation of several immune pathways, including those mediating anti-bacterial resistance and combating viral infections, upon heat exposure. The immunomodulatory role of HSPs indicates their potential use as an immunostimulant to enhance shrimp health for control of disease in aquaculture.

Cigarette smoke and extracellular Hsp70 induce secretion of ATP and differential activation of NLRP3 inflammasome in monocytic and bronchial epithelial cells

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease mainly caused by smoking. Cigarette smoke damages airway epithelium and activates lung macrophages, causing inflammatory responses. It was suggested that nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome might have an important role in COPD development. Study aimed to explore whether cigarette smoke extract (CSE), extracellular heat shock protein 70 (eHsp70) or their combinations induce adenosine triphosphate (ATP) release and NLRP3 inflammasome activation.

METHODS

We detected NLRP3 and interleukin (IL)-1β mRNA expression, extracellular IL-1β and ATP concentrations as well as lactate dehydrogenase (LDH) activity. We used bronchial epithelial (NCI-H292, 16HBE and NHBE) and monocytic cells (monocyte-derived macrophages (MDMs) and THP-1) as representative of local airway and systemic compartments that could be affected in COPD.

RESULTS

CSE and eHsp70 increased NLRP3 and IL-1β mRNA expression as well as IL-1β and ATP secretion in all cells compared to untreated cells. Lytic cell death was observed in cell lines, especially those of bronchial epithelium origin, but not in primary cells (NHBE, MDMs). Regarding LDH activity, eHsp70 did not modulate CSE effects, except in NCI-H292 cell line. However, eHsp70 significantly affected CSE-provoked NLRP3 inflammasome activation by causing mostly antagonistic effects in airway epithelial cells and synergistic effects in MDMs.

CONCLUSION

We demonstrated that both CSE and eHsp70 induce ATP secretion and differential activation of NLRP3 inflammasome in bronchial epithelial and monocytic cells. We suggest that these mechanisms might be involved in pathophysiology of COPD by contributing to the propagation of inflammation.

Pathogen-associated molecular patterns and extracellular Hsp70 interplay in NLRP3 inflammasome activation in monocytic and bronchial epithelial cellular models of COPD exacerbations

During chronic obstructive pulmonary disease (COPD) exacerbations, interplay between pathogen-associated molecular patterns (PAMPs; e.g. lipopolysaccharide (LPS) and lipoteichoic acid (LTA)) and damage-associated molecular patterns (DAMPs; e.g. extracellular heat shock protein 70 (eHsp70) and adenosine triphosphate (ATP)) might influence patient's outcome. Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome might have a role in dysfunctional immune system in COPD. We hypothesized that LPS, LTA, eHsp70 and their combinations induce NLRP3 inflammasome activation, and we aimed to explore this assumption. We used monocytic (monocyte-derived macrophages (MDMs) and THP-1) and bronchial epithelial cells (NHBE and NCI-H292) to represent systemic and local airway compartments that could be affected in COPD. Bacterial components and eHsp70 stimulated NLRP3 and interleukin (IL)-1β gene expression as well as IL-1β and ATP release from all cells compared to non-treated cells. LDH secretion was induced in cell lines only. eHsp70 had inhibitory (NCI-H292) or stimulatory (NHBE) effects on eATP levels compared to PAMP alone. Regarding NLRP3 inflammasome activation, eHsp70 had mostly antagonistic effects. We demonstrated that bacterial components and eHsp70 activate NLRP3 inflammasome and increase ATP secretion. We suggest that extracellular Hsp70 might modulate immune responses provoked by bacterial infections and affect COPD patients' outcome during acute exacerbations.

Effects of extracellular Hsp70, lipopolysaccharide and lipoteichoic acid on human monocyte-derived macrophages and differentiated THP-1 cells

Extracellular Hsp70 (eHsp70) is elevated in blood of patients with inflammatory diseases (e.g. chronic obstructive pulmonary disease), prone to bacterial infections. It stimulates pro-inflammatory effects in cells via TLR2 and TLR4. The main hypothesis was that eHsp70 induces inflammation and alters inflammatory responses to lipopolysaccharide (LPS) and lipoteichoic acid (LTA). We assessed pro-inflammatory cytokines concentrations, TLR2, TLR4 and Hsp70 mRNA expressions, NF-κB and MAPKs activation, and viability after treatment of monocyte-derived macrophages (MDMs) and THP-1 cells with recombinant human (rh) Hsp70, LPS and LTA. rhHsp70, LPS, LTA and their combinations induced IL-6, IL-8 and TNF-α from MDMs. LPS, LTA, and combinations with rhHsp70 increased TLR2 and decreased TLR4 in both cells. rhHsp70 increased TLR2 and TLR4 in THP-1 cells, and TLR2 in MDMs. rhHsp70, LPS and their combinations up-regulated Hsp70 in MDMs, while down-regulated it in THP-1. LPS and its combinations with rhHsp70 lowered cell viability in THP-1 cells and activated caspases-8 and -9. Involvement of NF-κB and MAPKs in inflammatory and survival mechanisms stimulated by rhHsp70 was demonstrated. eHsp70 alone and in combination with bacterial components could provoke inflammation and affect viability of MDMs and THP-1 cells leading to disturbed inflammatory responses in diseases accompanied with bacterial colonisations or infections.

Association of Plasma Heat Shock Protein 70 with Disease Severity, Smoking and Lung Function of Patients with Chronic Obstructive Pulmonary Disease

Extracellular heat shock protein 70 (eHsp70) might modulate immune responses in chronic obstructive pulmonary disease (COPD). The aim of the study was to explore eHsp70 concentration in stable COPD, its association with disease severity and smoking status as well as its diagnostic performance in COPD assessment. Plasma samples were collected from 137 COPD patients and 95 healthy individuals, and concentration of eHsp70 was assessed by commercially available enzyme-linked immunosorbent assay (ELISA) kit (Enzo Life Science, Farmingdale, NY, USA). COPD patients were subdivided regarding airflow obstruction severity and symptoms severity according to the Global Initiative for COPD (GOLD) guidelines. eHsp70 concentration increased in COPD patients when compared to controls and increased with the severity of airflow limitation as well as symptoms burden and exacerbation history. eHsp70 concentration did not differ among COPD patients based on smoking status, yet it increased in healthy smokers compared to healthy nonsmokers. In addition, eHsp70 negatively correlated with lung function parameters forced expiratory volume in one second (FEV₁) and FEV₁/ forced vital capacity (FVC), and positively with COPD multicomponent indices BODCAT (BMI, airflow obstruction, dyspnea, CAT score), BODEx (BMI, airflow obstruction, dyspnea, previous exacerbations), CODEx (Charlson’s comorbidity index, airflow obstruction, dyspnea, previous exacerbations) and DOSE (dyspnea, airflow obstruction, smoking status, previous exacerbations) With great predictive value (OR = 7.63) obtained from univariate logistic regression, eHsp70 correctly classified 76% of cases. eHsp70 is associated with COPD prediction and disease severity and might have the potential for becoming an additional biomarker in COPD assessment.

HSP70, a Novel Regulatory Molecule in B Cell-Mediated Suppression of Autoimmune Diseases

B cells have recently emerged as playing regulatory role in autoimmune diseases. We have previously demonstrated that human peripheral blood CD19⁺CD24^hiCD27⁺ B cells have regulatory function both in healthy donors and in patients with autoimmune disease. However, the mechanism of this regulation is still not fully understood. In this study, microarrays were utilized to compare gene expression of CD19⁺CD24^hiCD27⁺ B cells (regulatory B cells, Bregs) with CD19⁺CD24^loCD27^- B cells (non-Bregs) in human peripheral blood. We found that heat shock protein 70 (HSP70) expression was significantly upregulated in Bregs. In vitro studies explored that HSP70 inhibition impaired the regulatory function of peripheral blood Bregs. In mouse models of autoimmune disease, using HSP70-deficient mice or HSP70 inhibitors, Bregs suppressed effector cells and rescued disease-associated phenotypes that were dependent on HSP70. Mechanistically, Bregs secreted HSP70, directly suppressing effector cells, such as T effect cells. These findings reveal that HSP70 is a novel factor that modulates Breg function and suggest that enhancing Breg-mediated production of HSP70 could be a viable therapy for autoimmune disease.

Pro-inflammatory effects of extracellular Hsp70 on NCI-H292 human bronchial epithelial cell line

Extracellular Hsp70 (eHsp70) exerts its biological actions via Toll-like receptors 2 and 4, and is increased in sera of chronic obstructive pulmonary disease (COPD) patients. The aim of this study was to explore the pro-inflammatory effects and cytotoxicity of eHsp70 alone and in combination with bacterial components lipoteichoic acid (LTA) and lipopolysaccharide (LPS) on NCI-H292 airway epithelial cells. NCI-H292 cells were treated with recombinant human Hsp70 protein (rhHsp70), LPS, LTA and their combinations for 4, 12, 24 and 48 hours. IL-6, IL-8 and TNF-α levels were measured by an ELISA method. Cell viability was determined by the MTS method, and caspase-3/7, caspase-8 and caspase-9 assays. rhHsp70 induced secretion of IL-6 and IL-8 in a concentration- and time-dependent manner, with the highest secretion at 24 hours. rhHsp70 combined with LTA had antagonistic and with LPS synergistic effect on IL-6 secretion, while the interactions between rhHsp70 and LPS or LTA on IL-8 were synergistic. TNF-α was not detected in the applied conditions. rhHsp70, LPS or LTA did not affect cell viability, and rhHsp70 even suppressed caspase-3/7 activities. We suggest that pro-inflammatory effects of eHsp70, together with other damaging molecules and/or COPD risk factors, might contribute to the aggravation of chronic inflammation in human bronchial epithelium.

Damage-Associated Molecular Patterns and Myeloid-Derived Suppressor Cells in Bronchoalveolar Lavage Fluid in Chronic Obstructive Pulmonary Disease Patients

Myeloid-derived suppressor cells (MDSCs) are present in the human lung microenvironment, and they may be involved in the local inflammatory process in chronic obstructive pulmonary disease (COPD). Chronic inflammation in COPD may induce immunogenic cell death of structural airway cells, causing the release of damage-associated molecular patterns (DAMPs). DAMPs may activate the innate and adaptive immune system. The relationship between MDSCs and DAMPs in COPD is poorly described in the available literature. Objectives. (1) Assessment of MDSC percentage and DAMP concentration in bronchoalveolar lavage fluid (BALF) and peripheral blood. (2) Analysis of the relationship between MDSC percentage and chosen DAMPs. Patients and Methods. 30 COPD patients were included. Using monoclonal antibodies directly conjugated with fluorochromes in flow cytometry, MDSCs were assessed in BALF and peripheral blood. The concentration of DAMPs was estimated using sandwich ELISA. Using the Bradford method, the total protein concentrations were evaluated. Results. The percentage of MDSCs among MC in BALF correlated well with the concentration of defensin and heat shock protein 27. Assessing the percentage of MDSCs among all leukocytes in BALF, we revealed a significant correlation with the concentration of defensin, hyaluronic acid, and surfactant protein A. No dependencies occurred between DAMPs and MDSCs in peripheral blood. Conclusion. MDSCs and DAMPs occur in the COPD patient lung microenvironment. Significant correlations between them found in BALF may indicate their influence on the local inflammatory process in COPD. These relationships allow better understanding of the inflammatory process in COPD.

Cigarette Smoke-Induced Oxidative Stress and Autophagy in Human Alveolar Epithelial Cell Line (A549 Cells)

Chronic exposure to cigarette smoke (CS) causes structural and functional changes in the respiratory tract. It is a major risk factor for cardiovascular and systemic pulmonary diseases. The aim of this study was to investigate the effect of acute CS exposure (2 h) on oxidative stress, heat shock protein 70 (HSP70) expression, autophagy (LC3 expression), and oxidative stress (DCF fluorescence) in human alveolar epithelial cell line A549. Cell culture medium was conditioned with CS using commercial cigarettes, and A549 cells were grown in modified media for 2 h. In some experiments, A549 cells were pretreated with 100 μM of L-buthionine-sulfoximine (BSO) for 24 h to induce glutathione (GSH) depletion. In the cells grown in CS-conditioned medium, GSH was depleted by more than 30%, and reactive oxygen species were increased. Moreover, there was a considerable overexpression of HSP70 and a substantial accumulation of LC3. Similar changes were found when the cells were pretreated with BSO. We conclude that the short-term exposure of epithelial cells to CS increases oxidative stress that entails enhanced autophagy activity.