Increased IFN-γ-producing Th17/Th1 cells and their association with lung function and current smoking status in patients with chronic obstructive pulmonary disease

The protective role of muscone in the development of COPD

Background

Muscone, a key component of musk, exhibits anti-inflammatory properties. However, its therapeutic potential in inflammatory lung diseases, such as chronic obstructive pulmonary disease (COPD), remains largely unexplored. This study aimed to investigate whether Muscone could exert a protective effect in a mouse model of COPD in vivo.

Methods

A COPD animal model was established by exposing mice to cigarette smoke (CS) and administering lipopolysaccharide (LPS) intranasally. After 4 weeks, mice were treated daily with dexamethasone (DEX) or different doses of Muscone for 3 weeks. Mouse body weight, lung function, and histopathology were determined. Serum levels of cytokines (IL-38, IL-1β, IL-17, TGF-β, IFN-γ) were measured using ELISA and qRT-PCR. Lung expression of CXCR3, IFN-γ, IL-17A, and RORγt was assessed by immunofluorescence.

Results

The body weight of COPD mice was significantly lower than that of Muscone-treated COPD mice, consistent with decreased lung function, accompanied by reduced circulating and lung IL-38 levels. After Muscone administration, lung function was significantly improved, accompanied by upregulation of circulating and lung anti-inflammatory cytokines, including IL-38, in a dose-dependent manner, while the expression of pro-inflammatory cytokines was significantly reduced. Additionally, Muscone significantly inhibited the protein expression of CXCR3, IFN-γ, IL-17A, and RORγt in lung tissues of COPD mice.

Conclusion

This study demonstrates that Muscone improves lung function in mice with COPD, potentially through a mechanism that may involve the modulation of cytokine expression, including the potential upregulation of anti-inflammatory cytokines such as IL-38. The precise underlying mechanisms of Muscone's therapeutic effects in COPD remain to be fully elucidated. Further research is needed to investigate the correlation between COPD lung pathophysiology and the specific effects of Muscone treatment, including a more detailed analysis of the balance between pro- and anti-inflammatory mediators in COPD animal models, particularly utilizing IL-38 GKO mice to further investigate the role of IL-38 in mediating the therapeutic effects of Muscone.

Smoking and osteoimmunology: Understanding the interplay between bone metabolism and immune homeostasis

Smoking continues to pose a global threat to morbidity and mortality in populations. The detrimental impact of smoking on health and disease includes bone destruction and immune disruption in various diseases. Osteoimmunology, which explores the communication between bone metabolism and immune homeostasis, aims to reveal the interaction between the osteoimmune systems in disease development. Smoking impairs the differentiation of mesenchymal stem cells and osteoblasts in bone formation while promoting osteoclast differentiation in bone resorption. Furthermore, smoking stimulates the Th17 response to increase inflammatory and osteoclastogenic cytokines that promote the receptor activator of NF-κB ligand (RANKL) signaling in osteoclasts, thus exacerbating bone destruction in periodontitis and rheumatoid arthritis. The pro-inflammatory role of smoking is also evident in delayed bone fracture healing and osteoarthritis development. The osteoimmunological therapies are promising in treating periodontitis and rheumatoid arthritis, but further research is still required to block the smoking-induced aggravation in these diseases.

Translational potential

This review summarizes the adverse effect of smoking on mesenchymal stem cells, osteoblasts, and osteoclasts and elucidates the smoking-induced exacerbation of periodontitis, rheumatoid arthritis, bone fracture healing, and osteoarthritis from an osteoimmune perspective. We also propose the therapeutic potential of osteoimmunological therapies for bone destruction aggravated by smoking.

Acidovorax temperans skews neutrophil maturation and polarizes Th17 cells to promote lung adenocarcinoma development

Change within the intratumoral microbiome is a common feature in lung and other cancers and may influence inflammation and immunity in the tumor microenvironment, affecting growth and metastases. We previously characterized the lung cancer microbiome in patients and identified Acidovorax temperans as enriched in tumors. Here, we instilled A. temperans in an animal model driven by mutant K-ras and Tp53. This revealed A. temperans accelerates tumor development and burden through infiltration of proinflammatory cells. Neutrophils exposed to A. temperans displayed a mature, pro-tumorigenic phenotype with increased cytokine signaling, with a global shift away from IL-1β signaling. Neutrophil to monocyte and macrophage signaling upregulated MHC II to activate CD4+ T cells, polarizing them to an IL-17A+ phenotype detectable in CD4+ and γδ populations (T17). These T17 cells shared a common gene expression program predictive of poor survival in human LUAD. These data indicate bacterial exposure promotes tumor growth by modulating inflammation.

Periodontitis aggravates COPD through the activation of γδ T cell and M2 macrophage

Chronic obstructive pulmonary disease (COPD) is a chronic systemic inflammatory disease with high morbidity and mortality. Periodontitis exacerbates COPD progression; however, the immune mechanisms by which periodontitis affects COPD remain unclear. Here, by constructing periodontitis and COPD mouse models, we demonstrated that periodontitis and COPD could mutually aggravate disease progression. For the first time, we found that the progression was associated with the activation of γδ T cells and M2 macrophages, and M2 polarization of macrophages was affected by γδ T cells activation. In the lung tissues of COPD with periodontitis, the activation of γδ T cells finally led to the increase of IL 17 and IFN γ expression and M2 macrophage polarization. Furthermore, we found that the periodontitis-associated bacteria Porphyromonas gingivalis (P. gingivalis) promoted the activation of γδ T cells and M2 macrophages ex vivo. The data from clinical bronchoalveolar lavage fluid (BALF) samples were consistent with the in vivo and ex vivo experiments. For the first time, our results identified the crucial role of γδ T-M2 immune mechanism in mediating periodontitis-promoted COPD progression. Therefore, targeting at periodontitis treatment and the γδ T-M2 immune mechanism might provide a new practical strategy for COPD prevention or control.IMPORTANCEPeriodontitis exacerbates chronic obstructive pulmonary disease (COPD) progression. For the first time, the current study identified that the impact of periodontitis on COPD progression was associated with the activation of γδ T cells and M2 macrophages and that M2 polarization of macrophages was affected by γδ T cells activation. The results indicated that targeting at periodontitis treatment and the γδ T-M2 immune mechanism might provide a new practical strategy for COPD prevention or control.

Umbilical Cord Mesenchymal Stromal/Stem Cells and Their Interplay with Th-17 Cell Response Pathway

As a form of immunomodulatory therapeutics, mesenchymal stromal/stem cells (MSCs) from umbilical cord (UC) tissue were assessed for their dynamic interplay with the Th-17 immune response pathway. UC-MSCs were able to modulate lymphocyte response by promoting a Th-17-like profile. Such modulation depended on the cell ratio of the cocultures as well as the presence of an inflammatory setting underlying their plasticity. UC-MSCs significantly increased the expression of IL-17A and RORγt but differentially modulated T cell expression of IL-23R. In parallel, the secretion profile of the fifteen factors (IL1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-22, IL-21, IL-23, IL-25, IL-31, IL-33, INF-γ, sCD40, and TNF-α) involved in the Th-17 immune response pathway was substantially altered during these cocultures. The modulation of these factors demonstrates the capacity of UC-MSCs to sense and actively respond to tissue challenges. Protein network and functional enrichment analysis indicated that several biological processes, molecular functions, and cellular components linked to distinct Th-17 signaling interactions are involved in several trophic, inflammatory, and immune network responses. These immunological changes and interactions with the Th-17 pathway are likely critical to tissue healing and may help to identify molecular targets that will improve therapeutic strategies involving UC-MSCs.

Astragaloside IV restores Th17/Treg balance via inhibiting CXCR4 to improve chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has a high fatality rate and poses a great threat to human health. Astragaloside IV (AS-IV) is proven to attenuate cigarette smoke (CS)-induced pulmonary inflammation, based on which this research focuses on the mechanism of AS-IV in COPD.

METHODS

To evaluate the effects of AS-IV, CD4+ T cells received different concentrations of AS-IV. CD4+ T cell viability, T helper 17 (Th17)/regulatory T (Treg) markers and CXCR4 expressions in CD4+ T cells or spleen/lung tissues were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay, quantitative real-time polymerase chain reaction and Western blot. The proportions of Treg and Th17 cells were assessed by flow cytometry. Enzyme-linked immune sorbent assay was employed to determine cytokine contents in serum and lung tissues.

RESULTS

AS-IV with concentration exceeding 40 µM inhibited CD4+ T cell viability. In vitro, AS-IV suppressed the expressions of CXCR4, retinoid-related orphan receptor γt (RORγt), and interleukin (IL)-17A as well as Th17 cells but promoted the expressions of forkhead box p3 (Foxp3) and IL-10 as well as Treg cells, while CXCR4 overexpression reversed the effects of AS-IV. In vivo, AS-IV alleviated COPD, and CS-induced Th17/Treg imbalance in mice and reduced CS-induced down-regulation of IL-10 in serum and lung tissues and Foxp3 and up-regulation of IL-1β, tumor necrosis factor alpha (TNF-α), IL-6, and IL-17A in serum and lung tissues and RORγt. AS-IV mitigated CS-induced CXCR4 up-regulation. Above effects of AS-IV on mice were offset by CXCR4 overexpression.

CONCLUSIONS

AS-IV restores Th17/Treg balance via impeding CXCR4 to ameliorate COPD.

Salivary interleukin-17A and interferon-γ levels are elevated in children with food allergies in China

Introduction

Food allergies have a substantial impact on patient health, but their mechanisms are poorly understood, and strategies for diagnosing, preventing, and treating food allergies are not optimal. This study explored the levels of and relationship between IL-17A and IFN-γ in the saliva of children with food allergies, which will form the basis for further mechanistic discoveries as well as prevention and treatment measures for food allergies.

Methods

A case-control study with 1:1 matching was designed. Based on the inclusion criteria, 20 case-control pairs were selected from patients at the Skin and Allergy Clinic and children of employees. IL-17A and IFN-γ levels in saliva were measured with a Luminex 200 instrument. A general linear model was used to analyze whether the salivary IL-17A and IFN-γ levels in the food allergy group differed from those in the control group.

Results

The general linear model showed a significant main effect of group (allergy vs. healthy) on the levels of IL-17A and IFN-γ. The mean IL-17A level (0.97 ± 0.09 pg/ml) in the food allergy group was higher than that in the healthy group (0.69 ± 0.09 pg/ml). The mean IFN-γ level (3.0 ± 0.43 pg/ml) in the food allergy group was significantly higher than that in the healthy group (1.38 ± 0.43 pg/ml). IL-17A levels were significantly positively related to IFN-γ levels in children with food allergies (r=0.79) and in healthy children (r=0.98).

Discussion

The salivary IL-17A and IFN-γ levels in children with food allergies were higher than those in healthy children. This finding provides a basis for research on new methods of diagnosing food allergies and measuring the effectiveness of treatment.

The Airway Microbiome-IL-17 Axis: a Critical Regulator of Chronic Inflammatory Disease

The respiratory tract is home to a diverse microbial community whose influence on local and systemic immune responses is only beginning to be appreciated. Increasing reports have linked changes in this microbiome to a range of pulmonary and extrapulmonary disorders, including asthma, chronic obstructive pulmonary disease and rheumatoid arthritis. Central to many of these findings is the role of IL-17-type immunity as an important driver of inflammation. Despite the crucial role played by IL-17-mediated immune responses in protection against infection, overt Th17 cell responses have been implicated in the pathogenesis of several chronic inflammatory diseases. However, our knowledge of the influence of bacteria that commonly colonise the respiratory tract on IL-17-driven inflammatory responses remains sparse. In this article, we review the current knowledge on the role of specific members of the airway microbiota in the modulation of IL-17-type immunity and discuss how this line of research may support the testing of susceptible individuals and targeting of inflammation at its earliest stages in the hope of preventing the development of chronic disease.

Immune predictors of hepatitis B surface antigen seroconversion in patients with hepatitis B reactivation

BACKGROUND

Hepatitis B surface antigen (HBsAg) seroconversion is sometimes observed in hepatitis B reactivation (rHBV), probably due to immune resetting and differentiation.

AIMS

To investigate sequential immune differentiation and abrogation of tolerance in patients with rHBV who achieved HBsAg seroconversion.

METHODS

We included 19 patients with chronic hepatitis B (CHBV; HBV DNA log10^3-8 ), 67 with rHBV (raised ALT [>5XULN], HBV DNAlog10^4-8 ) and 10 healthy controls. Immune differentiation, tolerance and functional status of CD4, CD8, T regulatory cells (Tregs), B cells and follicular T helper (Tfh) cells were assessed at baseline and 24 weeks.

RESULTS

At 24 weeks, 81% rHBV (n = 67) lost HBV DNA and HBeAg (41%), and 12 (19%) lost HBsAg and made anti-HBs titers >10 IU/ml. rHBV patients had higher Th1/17, T_EM , Tfh, Tfh1/17, plasma and ATM B cells, and lower Tregs, Th2, Th17 and TEMRA expression. rHBV showed lower PD1, TIM3, LAG3, SLAM and TOX compared to CHBV. There was a significant increase in CD8, CD8EM, Tfh, Tfh1/17 and plasma B cells in seroconverters than non-seroconverters. At 24 weeks, we also observed increased plasma B cell frequency in seroconverters. While non-seroconverters showed higher expression of PD1, TIM3, LAG3, SLAM and TOX on CD4/CD8 T cells, blockade of PD1, TIM3, LAG3 and CTLA4 significantly enhanced IFN-γ, TNF-α, IL-4 and IL-21 expression on CD4/CD8 and Tfh cells in non-seroconverters.

CONCLUSIONS

Non-seroconverters have increased inhibitory markers on CD4/CD8 T cells. There is a critical play of CD8, Tfh and B cells and subsets in seroclearance, along with checkpoint molecules as a potential therapy for non-seroconverters in HBV infection.

Interleukin (IL)-33 immunobiology in asthma and airway inflammatory diseases

OBJECTIVE

Identify key features of IL-33 immunobiology important in allergic and nonallergic airway inflammatory diseases and potential therapeutic strategies to reduce disease burden.

DATA SOURCES

PubMed, clinicaltrials.gov.

STUDY SELECTIONS

A systematic and focused literature search was conducted of PubMed from March 2021 to December 2021 using keywords to either PubMed or BioMed Explorer including IL-33/ST2, genetic polymorphisms, transcription, translation, post-translation modification, nuclear protein, allergy, asthma, and lung disease. Clinical trial information on IL-33 was extracted from clinicaltrials.gov in August 2021.

RESULTS

In total, 72 publications with relevance to IL-33 immunobiology and/or clinical lung disease were identified (allergic airway inflammation/allergic asthma n = 26, non-allergic airway inflammation n = 9, COPD n = 8, lung fibrosis n = 10). IL-33 levels were higher in serum, BALF and/or lungs across inflammatory lung diseases. Eight studies described viral infections and IL-33 and 4 studies related to COVID-19. Mechanistic studies (n = 39) including transcript variants and post-translational modifications related to the immunobiology of IL-33. Single nucleotide polymorphism in IL-33 or ST2 were described in 9 studies (asthma n = 5, inflammatory bowel disease n = 1, mycosis fungoides n = 1, ankylosing spondylitis n = 1, coronary artery disease n = 1). Clinicaltrials.gov search yielded 84 studies of which 17 were related to therapeutic or biomarker relevance in lung disease.

CONCLUSION

An integral role of IL-33 in the pathogenesis of allergic and nonallergic airway inflammatory disease is evident with several emerging clinical trials investigating therapeutic approaches. Current data support a critical role of IL-33 in damage signaling, repair and regeneration of lungs.

Cytokine Secretion Dynamics of Isolated PBMC after Cladribine Exposure in RRMS Patients

Cladribine (CLD) treats multiple sclerosis (MS) by selectively and transiently depleting B and T cells with a secondary long-term reconstruction of the immune system. This study provides evidence of CLD’s immunomodulatory role in peripheral blood mononuclear cells (PBMCs) harvested from 40 patients with untreated relapsing-remitting MS (RRMS) exposed to CLD. We quantified cytokine secretion from PBMCs isolated by density gradient centrifugation with Ficoll−Paque using xMAP technology on a FlexMap 3D analyzer with a highly sensitive multiplex immunoassay kit. The PBMC secretory profile was evaluated with and without CLD exposure. PBMCs isolated from patients with RRMS for ≤12 months had significantly higher IL-4 but significantly lower IFN-γ and TNF-α secretion after CLD exposure. PBMCs isolated from patients with RRMS for >12 months had altered inflammatory ratios toward an anti-inflammatory profile and increased IL-4 but decreased TNF-α secretion after CLD exposure. CLD induced nonsignificant changes in IL-17 secretion in both RRMS groups. Our findings reaffirm CLD’s immunomodulatory effect that induces an anti-inflammatory phenotype.

Involvement of Molecular Mechanisms between T/B Cells and IL-23: From Palmoplantar Pustulosis to Autoimmune Diseases

Palmoplantar pustulosis (PPP) is a disease that causes recurrent blisters and aseptic pustules on the palms and soles. It has been suggested that both innate and acquired immunity are involved. In particular, based on the tonsils and basic experiments, it has been assumed that T and B cells are involved in its pathogenesis. In addition, the results of clinical trials have suggested that IL-23 is closely related to the pathogenesis. This review describes PPP and the genetic background, the factors involved in the onset and exacerbation of disease and its relation to the molecular mechanism. In addition, we describe the usefulness of biological therapy and its implications in relation to the importance in pathology, the pathogenesis of PPP, the importance of the role of the IL-23-Th17 axis and IL-36 in PPP. Furthermore, we describe an animal experimental model of PPP, the efficacy and mechanism of action of guselkumab, an anti-IL-23 antibody, the latest research, and finally the possibility for it to be effective for other autoimmune diseases.

Role of CD4+ T and CD8+ T Lymphocytes-Mediated Cellular Immunity in Pathogenesis of Chronic Obstructive Pulmonary Disease

This work was to explore the changes of T lymphocyte subsets in peripheral blood of patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) (AECOPD) and the role of cellular immunity mediated in the disease process. Eighty-six patients with AECOPD who visited Qingdao Hiser Medical Center from June 2020 to December 2021 and 30 healthy people (controls) who underwent health examination in the same period were selected. The differences of pulmonary function (PF), arterial blood gas (ABG), blood routine inflammatory indexes, T lymphocyte and T lymphocyte subsets were compared between the two groups, and the correlation between T lymphocyte subsets and each index was analyzed. There were clear differences in PF, ABG, and PB inflammation indexes between AECOPD patients and the controls (P <0.05). Compared with the controls, the CD₄⁺ and CD₄⁺/CD₈⁺ ratio in PB of AECOPD group were obviously decreased, and the CD₈⁺ level was clearly increased (P <0.05); Th1 of CD₄⁺ cell subsets and Tc1 of CD₈⁺ cell subsets were significantly increased, while Th2 of CD₄⁺ cell subsets and Tc2 of CD₈⁺ cell subsets were obviously decreased (P <0.05). However, CD4⁺ was significantly positively correlated with lung function indexes, and significantly negatively correlated with neutrophils/lymphocytes and high-sensitivity C-reactive protein (P <0.05) and significantly positively correlated with Hs-CRP (P <0.05). In summary, CD4+ and CD8⁺ T lymphocytes were involved in the occurrence and occurrence of AECOPD, the decrease of CD4⁺ and the increase of CD8⁺ may promote the deterioration of COPD.

Single-cell analysis implicates Th17 to Th2 cell plasticity in the pathogenesis of palmoplantar pustulosis

BACKGROUND

Palmoplantar pustulosis (PPP) is a severe inflammatory skin disorder, characterised by eruptions of painful, neutrophil-filled pustules on the palms and soles. While PPP has a profound effect on quality of life, it remains poorly understood and notoriously difficult to treat.

OBJECTIVE

We sought to investigate the immune pathways that underlie the pathogenesis of PPP.

METHODS

We applied bulk- and single-cell RNA-sequencing methods to the analysis of skin biopsies and peripheral blood mononuclear cells. We validated our results by flow cytometry and immune fluorescence microscopy RESULTS: Bulk RNA-sequencing of patient skin detected an unexpected signature of T-cell activation, with a significant overexpression of several Th2 genes typically upregulated in atopic dermatitis. To further explore these findings, we carried out single-cell RNA-sequencing in peripheral blood mononuclear cells of healthy and affected individuals. We found that the memory CD4+T-cells of PPP patients were skewed towards a Th17 phenotype, a phenomenon that was particularly significant among CLA+ skin-homing cells. We also identified a subset of memory CD4+ T-cells which expressed both Th17 (KLRB1/CD161) and Th2 (GATA3) markers, with pseudo-time analysis suggesting that the population was the result of Th17 to Th2 plasticity. Interestingly, the GATA3+/CD161+ cells were over-represented among the PBMCs of affected individuals, both in the scRNA-seq dataset and in independent flow-cytometry experiments. Dual positive cells were also detected in patient skin by means of immune fluorescence microscopy.

CONCLUSIONS

These observations demonstrate that PPP is associated with complex T-cell activation patterns and may explain why biologics that target individual T-helper populations have shown limited therapeutic efficacy.

CLINICAL IMPLICATIONS

The simultaneous activation of Th17 and Th2 responses in PPP supports the therapeutic use of agents that inhibit multiple T-cell pathways.

SARS-CoV-2-specific T cells associate with inflammation and reduced lung function in pulmonary post-acute sequalae of SARS-CoV-2

As of January 2022, at least 60 million individuals are estimated to develop post-acute sequelae of SARS-CoV-2 (PASC) after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While elevated levels of SARS-CoV-2-specific T cells have been observed in non-specific PASC, little is known about their impact on pulmonary function which is compromised in the majority of these individuals. This study compares frequencies of SARS-CoV-2-specific T cells and inflammatory markers with lung function in participants with pulmonary PASC and resolved COVID-19 (RC). Compared to RC, participants with respiratory PASC had between 6- and 105-fold higher frequencies of IFN-γ- and TNF-α-producing SARS-CoV-2-specific CD4+ and CD8+ T cells in peripheral blood, and elevated levels of plasma CRP and IL-6. Importantly, in PASC participants the frequency of TNF-α-producing SARS-CoV-2-specific CD4+ and CD8+ T cells, which exhibited the highest levels of Ki67 indicating they were activity dividing, correlated positively with plasma IL-6 and negatively with measures of lung function, including forced expiratory volume in one second (FEV1), while increased frequencies of IFN-γ-producing SARS-CoV-2-specific T cells associated with prolonged dyspnea. Statistical analyses stratified by age, number of comorbidities and hospitalization status demonstrated that none of these factors affect differences in the frequency of SARS-CoV-2 T cells and plasma IL-6 levels measured between PASC and RC cohorts. Taken together, these findings demonstrate elevated frequencies of SARS-CoV-2-specific T cells in individuals with pulmonary PASC are associated with increased systemic inflammation and decreased lung function, suggesting that SARS-CoV-2-specific T cells contribute to lingering pulmonary symptoms. These findings also provide mechanistic insight on the pathophysiology of PASC that can inform development of potential treatments to reduce symptom burden.

Cellular Immune Signal Exchange From Ischemic Stroke to Intestinal Lesions Through Brain-Gut Axis

As a vital pivot for the human circulatory system, the brain-gut axis is now being considered as an important channel for many of the small immune molecules’ transductions, including interleukins, interferons, neurotransmitters, peptides, and the chemokines penetrating the mesentery and blood brain barrier (BBB) during the development of an ischemic stroke (IS). Hypoxia-ischemia contributes to pituitary and neurofunctional disorders by interfering with the molecular signal release and communication then providing feedback to the gut. Suffering from such a disease on a long-term basis may cause the peripheral system’s homeostasis to become imbalanced, and it can also lead to multiple intestinal complications such as gut microbiota dysbiosis (GMD), inflammatory bowel disease (IBD), necrotizing enterocolitis (NEC), and even the tumorigenesis of colorectal carcinoma (CRC). Correspondingly, these complications will deteriorate the cerebral infarctions and, in patients suffering with IS, it can even ruin the brain’s immune system. This review summarized recent studies on abnormal immunological signal exchange mediated polarization subtype changes, in both macrophages and microglial cells as well as T-lymphocytes. How gut complications modulate the immune signal transduction from the brain are also elucidated and analyzed. The conclusions drawn in this review could provide guidance and novel strategies to benefit remedies for both IS and relative gut lesions from immune-prophylaxis and immunotherapy aspects.

IL-26 in asthma and COPD

INTRODUCTION

New targets are needed to enable more accurate diagnosis, monitoring and effective therapy in uncontrolled asthma and chronic obstructive pulmonary disease (COPD), two disorders characterized by pathogenic alterations in the innate immune response. Interestingly, the IL-10-related cytokine IL-26 has been found to be abundantly expressed in human airways and alterations in its expression have been linked to reduced lung function and markers of neutrophilic inflammation in patients with uncontrolled asthma or COPD.

AREAS COVERED

Literature search was conducted on PubMed to identify articles in the field of IL-26 immunology, as well as clinical studies on IL-26 in asthma and COPD, published between 2000 and 2021. We outline the main sources of IL-26 in human airways, as well as the effect of this cytokine on relevant immune and structural cells. Finally, we discuss the potential involvement of IL-26 in the pathophysiology of uncontrolled asthma and COPD.

EXPERT OPINION

IL-26 constitutes a potential target for diagnostic purposes and therapeutic modulation of the innate immune response in the airways of patients with asthma and COPD. It seems reasonable to expect more conclusive evidence of its clinical utility for personalized medicine within the coming 5-year period.

Th17/Treg Imbalance in Chronic Obstructive Pulmonary Disease: Clinical and Experimental Evidence

The imbalance between pro- and anti-inflammatory immune responses mediated by Th17 and Treg cells is deeply involved in the development and progression of inflammation in chronic obstructive pulmonary disease (COPD). Several clinical and experimental studies have described the Th17/Treg imbalance in COPD progression. Due to its importance, many studies have also evaluated the effect of different treatments targeting Th17/Treg cells. However, discrepant results have been observed among different lung compartments, different COPD stages or local and systemic markers. Thus, the data must be carefully examined. In this context, this review explores and summarizes the recent outcomes of Th17/Treg imbalance in COPD development and progression in clinical, experimental and in vitro studies.

Activation of immune cell proteasomes in peripheral blood of smokers and COPD patients - implications for therapy

Immune cells contain a specialised type of proteasome, i.e. the immunoproteasome, which is required for intracellular protein degradation. Immunoproteasomes are key regulators of immune cell differentiation, inflammatory activation and autoimmunity. Immunoproteasome function in peripheral immune cells might be altered by smoking and in COPD thereby affecting immune cell responses.We here analysed the expression and activity of proteasome complexes in peripheral blood mononuclear cells (PBMC) isolated from healthy male young smokers as well as from patients with severe COPD and compared them to matching controls. Proteasome expression was upregulated in COPD patients as assessed by RT-qPCR and mass spectrometry-based proteomics analysis. Proteasome activity was quantified using activity-based probes and native gel analysis. We observed distinct activation of immunoproteasomes in the peripheral blood cells of young male smokers and severely ill COPD patients. Native gel analysis and linear regression modeling confirmed robust activation and elevated assembly of 20S proteasomes, which correlated significantly with reduced lung function parameters in COPD patients. The immunoproteasome was distinctly activated in COPD patients upon inflammatory cytokine stimulation of PBMCs in vitro Inhibition of the immunoproteasome reduced proinflammatory cytokine expression in COPD-derived blood immune cells.Given the crucial role of chronic inflammatory signalling and the emerging involvement of autoimmune responses in COPD, therapeutic targeting of the immunoproteasome might represent a novel therapeutic concept for COPD.

Oxidative Stress Promotes Corticosteroid Insensitivity in Asthma and COPD

Corticosteroid insensitivity is a key characteristic of patients with severe asthma and COPD. These individuals experience greater pulmonary oxidative stress and inflammation, which contribute to diminished lung function and frequent exacerbations despite the often and prolonged use of systemic, high dose corticosteroids. Reactive oxygen and nitrogen species (RONS) promote corticosteroid insensitivity by disrupting glucocorticoid receptor (GR) signaling, leading to the sustained activation of pro-inflammatory pathways in immune and airway structural cells. Studies in asthma and COPD models suggest that corticosteroids need a balanced redox environment to be effective and to reduce airway inflammation. In this review, we discuss how oxidative stress contributes to corticosteroid insensitivity and the importance of optimizing endogenous antioxidant responses to enhance corticosteroid sensitivity. Future studies should aim to identify how antioxidant-based therapies can complement corticosteroids to reduce the need for prolonged high dose regimens in patients with severe asthma and COPD.

LncRNA CASC2 is involved in the development of chronic obstructive pulmonary disease via targeting miR-18a-5p/IGF1 axis

AIMS

Chronic obstructive pulmonary disease (COPD) is a systemic disease. Several long non-coding RNAs (lncRNAs) have been identified to be aberrantly expressed in COPD patients. This study investigated the role of lncRNA cancer susceptibility candidate 2 (CASC2) in COPD, as well as its potential mechanism.

METHODS

Fifty smokers with COPD and another 50 smokers without COPD were recruited. Receiver operating characteristic curve was constructed to assess the diagnostic value of CASC2 in COPD patients. 16HBE cells were treated with cigarette smoke extract (CSE) to establish a cell model. qRT-PCR was used for the measurement of mRNA levels. The cell viability and apoptosis were detected by using Cell Counting Kit-8 and flow cytometry assay. Enzyme-linked immunosorbent assay was performed to detect the levels of proinflammatory cytokines. Luciferase reporter assay was performed for the target gene analysis.

RESULTS

Serum CASC2 was dramatically decreased in COPD patients compared with smokers without COPD, and was positively associated with FEV1 (forced expiratory volume in one second). Serum CASC2 was overexpressed in severe COPD patients, and had the diagnostic accuracy to distinguish COPD patients from smokers. CASC2 overexpression alleviated CSE-induced apoptosis and inflammation in 16HBE cells. CASC2 functions as a ceRNA of miR-18a-5p. Upregulation of miR-18a-5p reversed the influence of CASC2 on cell apoptosis and inflammation in 16HBE cells. IGF1 was the target gene of miR-18a-5p.

CONCLUSION

CASC2 was downregulated in COPD patients and it might be a promising biomarker for the disease diagnosis. Overexpression of CASC2 might inhibit the bronchial epithelial cell apoptosis and inflammation via targeting miR-18a-5p/IGF1 axis.The reviews of this paper are available via the supplemental material section.

Receptor Activator of Nuclear Factor (Nf)-kb Ligand Promotes T Helper 17 Cell Differentiation through Fas

T helper 17 (Th17) cells play important role in the defense against pathogens and autoimmune diseases. Many cytokines can induce Th17 cell differentiation. However, the mechanism of Th17 cell differentiation is not well clarified. RankL, a member of the TNF superfamily, binds with Rank and then participates in the proliferation and differentiation of many kinds of cells. Recent studies showed that RankL-Rank signaling is closely related to Th17 differentiation and function. The detail of the Rank-RankL pathway in Th17 cell differentiation is still unclear. To illustrate the role of Rank-RankL in Th17 differentiation, naive CD4 + T cells were differentiated into Th17 cells with or without RankL stimulation. During Th17 differentiation, the expression of Rank obviously increased. The RankL stimulation significantly increased Th17 cell differentiation indicated by increased IL-17-positive cell number, highly expressed IL-17 and IL-22 and elevated IL-17 secretion. These effects were canceled by Rank-Fc addition. In further study, RankL treatment during Th17 differentiation up-regulated Fas expression. Fas knockdown inhibited the Th17 differentiation promoted by RankL. In this study, it was confirmed that Rank-RankL signaling could promote Th17 cell differentiation through Fas induction.

Meibomian gland dysfunction is suppressed via selective inhibition of immune responses by topical LFA-1/ICAM antagonism with lifitegrast in the allergic eye disease (AED) model

PURPOSE

The etiology of meibomian gland dysfunction (MGD) is incompletely understood, despite being a common ophthalmic condition and an area of unmet medical need. It is characterized by an insufficiency in glandular provision of specialized lipids (meibum) to the tear film and is a major cause of dry eye. Work in the allergic eye disease (AED) mouse model has revealed an immunopathogenic role in MGD causation, now raising interest in the applicability of immunomodulatory therapies. As such, we herein ask whether inhibition of lymphocyte function associated antigen (LFA)-1/intracellular adhesion molecules (ICAM)-1 signaling via topical lifitegrast administration has a therapeutic effect on MGD in AED mice.

METHODS

Mice were induced with AED by i.p. injection of ovalbumin (OVA) mixed with alum and pertussis toxin, followed 2 weeks later by once daily topical OVA challenges for 7 days. Mice were treated topically with 5% lifitegrast ophthalmic solution or vehicle (PBS) 30 min prior to challenge. We developed a clinical ranking method to assess MGD severity, and also scored clinical allergy. Conjunctivae and draining lymph nodes were collected for flow cytometry.

RESULTS

Topical lifitegrast significantly inhibited clinical MGD severity, which was associated with diminished pathogenic TH17 cell and neutrophil numbers in the conjunctiva. No significant change in conjunctival TH2 cells or eosinophils, and only marginal differences in ocular allergy were observed.

CONCLUSIONS

In AED mice, lifitegrast inhibited MGD severity marked by a reduction in select immune populations in the conjunctiva. Our findings warrant future examination of lifitegrast in the treatment of patients with forms of MGD.

Quantification and role of innate lymphoid cell subsets in Chronic Obstructive Pulmonary Disease

Objectives

Innate lymphoid cells (ILCs) secrete cytokines, such as IFN‐γ, IL‐13 and IL‐17, which are linked to chronic obstructive pulmonary disease (COPD). Here, we investigated the role of pulmonary ILCs in COPD pathogenesis.

Methods

Lung ILC subsets in COPD and control subjects were quantified using flow cytometry and associated with clinical parameters. Tissue localisation of ILC and T‐cell subsets was determined by immunohistochemistry. Mice were exposed to air or cigarette smoke (CS) for 1, 4 or 24 weeks to investigate whether pulmonary ILC numbers and activation are altered and whether they contribute to CS‐induced innate inflammatory responses.

Results

Quantification of lung ILC subsets demonstrated that ILC1 frequency in the total ILC population was elevated in COPD and was associated with smoking and severity of respiratory symptoms (COPD Assessment Test [CAT] score). All three ILC subsets localised near lymphoid aggregates in COPD. In the COPD mouse model, CS exposure in C57BL/6J mice increased ILC numbers at all time points, with relative increases in ILC1 in bronchoalveolar lavage (BAL) fluid. Importantly, CS exposure induced increases in neutrophils, monocytes and dendritic cells that remained elevated in Rag2/Il2rg‐deficient mice that lack adaptive immune cells and ILCs. However, CS‐induced CXCL1, IL‐6, TNF‐α and IFN‐γ levels were reduced by ILC deficiency.

Conclusion

The ILC1 subset is increased in COPD patients and correlates with smoking and severity of respiratory symptoms. ILCs also increase upon CS exposure in C57BL/6J mice. In the absence of adaptive immunity, ILCs contribute to CS‐induced pro‐inflammatory mediator release, but are redundant in CS‐induced innate inflammation.

TGF-β: The missing link in obesity-associated airway diseases?

Obesity is emerging as a global public health epidemic. The co-morbidities associated with obesity significantly contribute to reduced quality of life, mortality, and global healthcare burden. Compared to other asthma comorbidities, obesity prominently engenders susceptibility to inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), contributes to greater disease severity and evokes insensitivity to current therapies. Unlike in other metabolic diseases associated with obesity, the mechanistic link between obesity and airway diseases is only poorly defined. Transforming growth factor-β (TGF-β) is a pleiotropic inflammatory cytokine belonging to a family of growth factors with pivotal roles in asthma. In this review, we summarize the role of TGF-β in major obesity-associated co-morbidities to shed light on mechanisms of the diseases. Literature evidence shows that TGF-β mechanistically links many co-morbidities with obesity through its profibrotic, remodeling, and proinflammatory functions. We posit that TGF-β plays a similar mechanistic role in obesity-associated inflammatory airway diseases such as asthma and COPD. Concerning the role of TGF-β on metabolic effects of obesity, we posit that TGF-β has a similar mechanistic role in obesity-associated inflammatory airway diseases in interplay with different comorbidities such as hypertension, metabolic diseases like type 2 diabetes, and cardiomyopathies. Future studies in TGF-β-dependent mechanisms in obesity-associated inflammatory airway diseases will advance our understanding of obesity-induced asthma and help find novel therapeutic targets for prevention and treatment.

Identification of biomarkers associated with clinical severity of chronic obstructive pulmonary disease

We sought to identify the biomarkers related to the clinical severity of stage I to stage IV chronic obstructive pulmonary disease (COPD). Gene expression profiles from the blood samples of COPD patients at each of the four stages were acquired from the Gene Expression Omnibus Database (GEO, accession number: GSE54837). Genes showing expression changes among the different stages were sorted by soft clustering. We performed functional enrichment, protein-protein interaction (PPI), and miRNA regulatory network analyses for the differentially expressed genes. The biomarkers associated with the clinical classification of COPD were selected from logistic regression models and the relationships between TLR2 and inflammatory factors were verified in clinical blood samples by qPCR and ELISA. Gene clusters demonstrating continuously rising or falling changes in expression (clusters 1, 2, and 7 and clusters 5, 6, and 8, respectively) from stage I to IV were defined as upregulated and downregulated genes, respectively, and further analyzed. The upregulated genes were enriched in functions associated with defense, inflammatory, or immune responses. The downregulated genes were associated with lymphocyte activation and cell activation. TLR2, HMOX1, and CD79A were hub proteins in the integrated network of PPI and miRNA regulatory networks. TLR2 and CD79A were significantly correlated with clinical classifications. TLR2 was closely associated with inflammatory responses during COPD progression. Functions associated with inflammatory and immune responses as well as lymphocyte activation may play important roles in the progression of COPD from stage I to IV. TLR2 and CD79A may serve as potential biomarkers for the clinical severity of COPD. TLR2 and CD79A may also serve as independent biomarkers in the clinical classification in COPD. TLR2 may play an important role in the inflammatory responses of COPD.

Immunomodulatory Effects of Hydrolyzed Seawater Pearl Tablet (HSPT) on Th1/Th2 Functionality in a Mice Model of Chronic Obstructive Pulmonary Disease (COPD) Induced by Cigarette Smoke

Chronic obstructive pulmonary disease (COPD) is predicted to become the third leading cause of death around the world. The present study is designed to investigate whether hydrolyzed seawater pearl tablet (HSPT) has immunoregulatory effects on the Th1/Th2 functionality in cigarette smoke-induced COPD model mice. The determination of the amino acid composition of HSPT was carried out by high-performance liquid chromatography (HPLC) with precolumn phenylisothiocyanate (PITC) derivatization. COPD model mice were constructed by cigarette smoking (CS) treatment and HSPT was administered. HSPT inhibited the infiltration of inflammation in the airway of the lung, reduced influx of eosinophils (EOSs), lymphocytes (LYMs), neutrophils (NEUs), and macrophages (MACs) in the bronchoalveolar lavage fluid (BALF), decreased the levels of IFN-γ, IL-2, IL-4, and IL-10 in the serum and lung, and decreased the expression of aforementioned cytokines in the spleen and lung in CS-treated mice. Besides, HSPT also had the ability to reduce the amount of CD3⁺CD4⁺ T cells and modulate the Th1/Th2 balance. Taken together, this study supports the consensus that CS is a critical factor to induce and aggravate COPD. HSPT could regulate the balance of Th1/Th2 in CS-induced COPD model mice, indicating its effects on inhibiting the development of COPD.

Systemic Cytokine Profiles of CD4+ T Lymphocytes Correlate with Clinical Features and Functional Status in Stable COPD

Aims

To evaluate the expressions of intracellular cytokines in CD4+ T lymphocytes and to investigate the correlation between biomarker expressions and clinical and functional characteristics of stable COPD patients.

Patients and Methods

Peripheral blood was collected from 36 COPD patients, and the expression of cytokines (IL-8, IL-13, IL-17, IL-6, IL-2, IL-10, and TNF-α) in T lymphocytes CD4 + was investigated. In addition, lung function, dyspnea symptoms, quality of life, vital signs, body composition, level of physical activity, peripheral muscle strength, and functional capacity were assessed.

Results

Individuals with greater bronchial obstruction present a higher proportion of CD4 + IL-2 + lymphocytes compared to individuals with less severe bronchial obstruction. We found a positive correlation between the expression of the cytokines IL-13, IL-17, IL-6, IL-2, IL-10, and TNF-α in CD4+ T lymphocytes. In addition, we found a positive correlation between CD4+ IL-10+ T lymphocytes and lower limb muscle strength and a negative correlation between CD4+ IL-8+ T lymphocytes and peripheral oxygen saturation and steps per day.

Conclusion

Systemic CD4+IL-2+, IL-8+, and IL-10+ T lymphocytes presented a correlation with clinical characteristics and functional status in stable COPD.