The axis of the receptor for advanced glycation endproducts in asthma and allergic airway disease

Bongkrekic acid alleviates airway inflammation via breaking the mPTP/mtDAMPs/RAGE feedback loop in a steroid-insensitive asthma model

Mitochondrial dysfunction is critical in the pathogenesis of asthma. Mitochondrial permeability transition pore (mPTP) regulates the release of mitochondrial damage-associated molecular patterns (mtDAMPs) to maintain mitochondrial homeostasis. Bongkrekic acid (BKA) is a highly selective inhibitor of mPTP opening, participates the progression of various diseases. This research investigated the exact roles of BKA and mPTP in the pathogenesis of asthma and elucidated its underlying mechanisms. In the present study, cytochrome c, one of the mtDAMPs, levels were elevated in asthmatic patients, and associated to airway inflammation and airway obstruction. BKA, the inhibitor of mPTP markedly reversed TDI-induced airway hyperresponsiveness, airway inflammation, and mitochondrial dysfunction. Pretreatment with mitochondrial precipitation, to simulate the release of mtDAMPs, further increased TDI-induced airway inflammation and the expression of RAGE in mice. Administration of the inhibitor of RAGE, FPS-ZM1, alleviated the airway inflammation, the abnormal open of mPTP and mitochondrial dysfunction induced by mtDAMPs and TDI. Furthermore, stimulation with different mtDAMPs activated RAGE signaling in human bronchial epithelial cells. Accordingly, our study indicated that mPTP was important and BKA was efficient in alleviating inflammation in TDI-induced asthma. A positive feedback loop involving mPTP, mtDAMPs and RAGE was present in TDI-induced asthma, indicating that mPTP might serve as a potential therapeutic target for asthma.

Nucleic Acid Therapeutics: Successes, Milestones, and Upcoming Innovation

Nucleic acid-based therapies have become the third major drug class after small molecules and antibodies. The role of nucleic acid-based therapies has been strengthened by recent regulatory approvals and tremendous clinical success. In this review, we look at the major obstacles that have hindered the field, the historical milestones that have been achieved, and what is yet to be resolved and anticipated soon. This review provides a view of the key innovations that are expanding nucleic acid capabilities, setting the stage for the future of nucleic acid therapeutics.

40 years of adding more fructose to high fructose corn syrup than is safe, through the lens of malabsorption and altered gut health-gateways to chronic disease

Labels do not disclose the excess-free-fructose/unpaired-fructose content in foods/beverages. Objective was to estimate excess-free-fructose intake using USDA loss-adjusted-food-availability (LAFA) data (1970-2019) for high fructose corn syrup (HFCS) and apple juice, major sources of excess-free-fructose, for comparison with malabsorption dosages (~ 5 g-children/ ~ 10 g-adults). Unlike sucrose and equimolar fructose/glucose, unpaired-fructose triggers fructose malabsorption and its health consequences. Daily intakes were calculated for HFCS that is generally-recognized-as-safe/ (55% fructose/45% glucose), and variants (65/35, 60/40) with higher fructose-to-glucose ratios (1.9:1, 1.5:1), as measured by independent laboratories. Estimations include consumer-level-loss (CLL) allowances used before (20%), and after, subjective, retroactively-applied increases (34%), as recommended by corn-refiners (~ 2012). No contributions from crystalline-fructose or agave syrup were included due to lack of LAFA data. High-excess-free-fructose-fruits (apples/pears/watermelons/mangoes) were not included. Eaten in moderation they are less likely to trigger malabsorption. Another objective was to identify potential parallel trends between excess-free-fructose intake and the "unexplained" US asthma epidemic. The fructose/gut-dysbiosis/lung axis is well documented, case-study evidence and epidemiological research link HFCS/apple juice intake with asthma, and unlike gut-dysbiosis/gut-fructosylation, childhood asthma prevalence data spans > 40 years. Results Excess-free-fructose daily intake for individuals consuming HFCS with an average 1.5:1 fructose-to-glucose ratio, ranged from 0.10 g/d in 1970, to 11.3 g/d in 1999, to 6.5 g/d in 2019, and for those consuming HFCS with an average 1.9:1 ratio, intakes ranged from 0.13 g/d to 16.9 g/d (1999), to 9.7 g/d in 2019, based upon estimates with a 20% CLL allowance. Intake exceeded dosages that trigger malabsorption (~ 5 g) around ~ 1980. By the early 1980's, tripled apple juice intake had added ~ 0.5 g to average-per-capita excess-free-fructose intake. Contributions were higher (~ 3.8 g /4-oz.) for individuals consuming apple juice consistent with a healthy eating pattern (4-oz. children, 8-oz. adults). The "unexplained" childhood asthma epidemic (1980-present) parallels increasing average-per-capita HFCS/apple juice intake trends and reflects epidemiological research findings. Conclusion Displacement of sucrose with HFCS, its ubiquitous presence in the US food-supply, the industry practice of adding more fructose to HFCS than generally-recognized-as-safe, and increased use of apple juice/crystalline fructose/agave syrup in foods/beverages has contributed to unprecedented excess-free-fructose intake levels, fructose malabsorption, gut-dysbiosis and gut-fructosylation (immunogen burden)-gateways to chronic disease.

The Role of Aldose Reductase in Polyol Pathway: An Emerging Pharmacological Target in Diabetic Complications and Associated Morbidities

The expression of aldose reductase leads to a variety of biological and pathological effects. It is a multifunctional enzyme which has a tendency to reduce aldehydes to the corresponding sugar.alcohol. In diabetic conditions, the aldose reductase enzyme converts glucose into sorbitol using nicotinamide adenine dinucleotide phosphate as a cofactor. It is a key enzyme in polyol pathway which is a surrogate course of glucose metabolism. The polyol pathway has a significant impact on the aetiology of complications in individuals with end-stage diabetes. The exorbitant level of sorbitol leads to the accumulation of intracellular reactive oxygen species in diabetic heart, neurons, kidneys, eyes and other vasculatures, leading to many complications and pathogenesis. Recently, the pathophysiological role of aldose reductase has been explored with multifarious perspectives. Research on aldose reductase suggest that besides implying in diabetic complications, the enzyme also turns down the lipid-derived aldehydes as well as their glutathione conjugates. Although aldose reductase has certain lucrative role in detoxification of toxic lipid aldehydes, its overexpression leads to intracellular accumulation of sorbitol which is involved in secondary diabetic complications, such as neuropathy, cataractogenesis, nephropathy, retinopathy and cardiovascular pathogenesis. Osmotic upset and oxidative stress are produced by aldose reductase via the polyol pathway. The inhibition of aldose reductase alters the activation of transcription factors like NF-ƙB. Moreover, in many preclinical studies, aldose reductase inhibitors have been observed to reduce inflammation-related impediments, such as asthma, sepsis and colon cancer, in diabetic subjects. Targeting aldose reductase can bestow a novel cognizance for this primordial enzyme as an ingenious strategy to prevent diabetic complications and associated morbidities. In this review article, the significance of aldose reductase is briefly discussed along with their prospective applications in other afflictions.

Investigation of the allergenicity alterations of shrimp tropomyosin as glycated by glucose and maltotriose containing advanced glycation end products

Tropomyosin (TM) is the major allergen in shrimp that is known to be the primary trigger for shrimp-induced food allergy. Our previous reports suggest that glycation could reduce the allergenicity of TM and the reduction of allergenicity is largely dependent on the sources of saccharides. This investigation aimed to investigate the glycation of TM by glucose and maltotriose as well as the effects of glycation on the allergenicity of TM. Compared to TM, the IgG-binding capacity and IgE-binding capacity of tropomyosin glycated by glucose (TM-G) was greatly reduced with a longer glycation time, the release of allergic mediators from RBL-2H3 mast cells was reduced in a time-dependent manner, and weaker allergic reactions were induced in BALB/c mice. Conversely, tropomyosin glycated by maltotriose (TM-MTS) exhibited a stronger allergenicity after 48 hours of glycation due to the generation of neoallergens that were derived from the advanced glycation end products (AGEs). In conclusion, glucose could be used to desensitize the shrimp TM-induced food allergy via glycation, which could significantly reduce the allergenicity and alleviate allergic symptoms. This work could provide a novel approach to reduce the allergenicity of shrimp tropomyosin and prevent the shrimp tropomyosin-induced food allergy.

Assessment of Fraction of Exhaled Nitric Oxide and Soluble Receptor for Advanced Glycation End Products Biomarkers for Jordanian Asthmatic Children

PURPOSE

Fraction of exhaled nitric oxide (FeNO) and soluble advanced glycation end-product receptor (sRAGE) are proposed as biomarkers of asthma, therefore we sought to assess their use in asthmatic children of Jordan.

PATIENTS AND METHODS

We conducted a case-control study at The University of Jordan Hospital. A total of 141 asthmatic children followed by respiratory pediatricians and 118 healthy children aged 4-18 years were recruited. FeNO was measured by NObreath device and serum sRAGE by ELISA that detect endogenously soluble isoform (esRAGE) and total soluble RAGE (sRAGE).

RESULTS

sRAGE in asthmatic was half of the control (p <0.001). In addition, ratio of esRAGE/sRAGE was two-fold higher in asthmatic (p = <0.001). Neither FeNO nor esRAGE levels were significantly different between groups. FeNO and asthma control test (ACT) score were negatively correlated corrected for age and body mass index (BMI), (r = -0.180, p= 0.034). For the uncontrolled asthma group, esRAGE/sRAGE negatively correlated with ACT score (r = -.329, p = 0.038). Receiver operating curve (ROC) analysis revealed significant predictive value (PV) for sRAGE and esRAGE/sRAGE in asthma detection with area under the curve (AUC) of (0.751 ± 0.031) and (0.711±.033), consequently. However, no biomarker had a significant PV for lack of control.

CONCLUSION

The current study supports utilizing sRAGE as a marker for asthma and present a potential therapeutic target. However, our results indicate that both FeNO and sRAGE have a limited role in the management of asthmatic children or assessment of asthma control.

Molecular and immune signatures, and pathological trajectories of fatal COVID-19 lungs defined by in situ spatial single-cell transcriptome analysis

Despite intensive studies during the last 3 years, the pathology and underlying molecular mechanism of coronavirus disease 2019 (COVID-19) remain poorly defined. In this study, we investigated the spatial single-cell molecular and cellular features of postmortem COVID-19 lung tissues using in situ sequencing (ISS). We detected 10 414 863 transcripts of 221 genes in whole-slide tissues and segmented them into 1 719 459 cells that were mapped to 18 major parenchymal and immune cell types, all of which were infected by SARS-CoV-2. Compared with the non-COVID-19 control, COVID-19 lungs exhibited reduced alveolar cells (ACs) and increased innate and adaptive immune cells. We also identified 19 differentially expressed genes in both infected and uninfected cells across the tissues, which reflected the altered cellular compositions. Spatial analysis of local infection rates revealed regions with high infection rates that were correlated with high cell densities (HIHD). The HIHD regions expressed high levels of SARS-CoV-2 entry-related factors including ACE2, FURIN, TMPRSS2 and NRP1, and co-localized with organizing pneumonia (OP) and lymphocytic and immune infiltration, which exhibited increased ACs and fibroblasts but decreased vascular endothelial cells and epithelial cells, mirroring the tissue damage and wound healing processes. Sparse nonnegative matrix factorization (SNMF) analysis of niche features identified seven signatures that captured structure and immune niches in COVID-19 tissues. Trajectory inference based on immune niche signatures defined two pathological routes. Trajectory A primarily progressed with increased NK cells and granulocytes, likely reflecting the complication of microbial infections. Trajectory B was marked by increased HIHD and OP, possibly accounting for the increased immune infiltration. The OP regions were marked by high numbers of fibroblasts expressing extremely high levels of COL1A1 and COL1A2. Examination of single-cell RNA-seq data (scRNA-seq) from COVID-19 lung tissues and idiopathic pulmonary fibrosis (IPF) identified similar cell populations consisting mainly of myofibroblasts. Immunofluorescence staining revealed the activation of IL6-STAT3 and TGF-β-SMAD2/3 pathways in these cells, likely mediating the upregulation of COL1A1 and COL1A2 and excessive fibrosis in the lung tissues. Together, this study provides a spatial single-cell atlas of cellular and molecular signatures of fatal COVID-19 lungs, which reveals the complex spatial cellular heterogeneity, organization, and interactions that characterized the COVID-19 lung pathology.

Emergent Inflammatory Markers and Echocardiographic Indices in Patients with Bronchial Asthma

Asthma is a heterogeneous disease, characterized by chronic inflammation and oxidative stress of the airways. Several inflammatory pathways including activation of the receptor for advanced glycation end products (RAGE) have been described in the course of the disease. DJ-1 is a redox-sensitive protein with multifaceted roles in mast cell homeostasis and an emerging role in the pathogenesis of asthma. Moreover, cardiac function abnormalities have been described via echocardiography in patients with asthma. The main aim of this study was to investigate the plasma levels of RAGE, its ligands and DJ-1 in asthmatic patients pre- and post-treatment along with echocardiographic indices of cardiovascular function. The study population was divided into two groups. Group A included 13 patients with newly diagnosed bronchial asthma who were free of treatment for at least two weeks and Group B included 12 patients without asthma. An echocardiography examination was performed on all patients. The plasma levels of RAGE, its ligands (AGEs, S100A12, S100B, S100A8/A9), the interleukins (IL-6, IL-1β) and DJ-1 were measured. No differences were noted among the two groups for baseline characteristics and echocardiographic indices of cardiac function. In Group A, 31% suffered from mild asthma, 54% from moderate asthma and 15% from severe asthma. Plasma levels of IL-6, AGEs and AGE/RAGE ratio were increased and those of S100A12 and DJ-1 were decreased in asthmatics. Pharmacotherapy with corticosteroids/β2-agonists decreased IL-6, and AGEs, and increased DJ-1. In search of novel approaches in diagnosing and treating patients with asthma, S100A12, ratio AGE/sRAGE, and DJ-1 in addition to IL-6 may prove to be useful tools.

The AGE-RAGE Axis and the Pathophysiology of Multimorbidity in COPD

Chronic obstructive pulmonary disease (COPD) is a disease of the airways and lungs due to an enhanced inflammatory response, commonly caused by cigarette smoking. Patients with COPD are often multimorbid, as they commonly suffer from multiple chronic (inflammatory) conditions. This intensifies the burden of individual diseases, negatively affects quality of life, and complicates disease management. COPD and comorbidities share genetic and lifestyle-related risk factors and pathobiological mechanisms, including chronic inflammation and oxidative stress. The receptor for advanced glycation end products (RAGE) is an important driver of chronic inflammation. Advanced glycation end products (AGEs) are RAGE ligands that accumulate due to aging, inflammation, oxidative stress, and carbohydrate metabolism. AGEs cause further inflammation and oxidative stress through RAGE, but also through RAGE-independent mechanisms. This review describes the complexity of RAGE signaling and the causes of AGE accumulation, followed by a comprehensive overview of alterations reported on AGEs and RAGE in COPD and in important co-morbidities. Furthermore, it describes the mechanisms by which AGEs and RAGE contribute to the pathophysiology of individual disease conditions and how they execute crosstalk between organ systems. A section on therapeutic strategies that target AGEs and RAGE and could alleviate patients from multimorbid conditions using single therapeutics concludes this review.

HMGB1 is a promising therapeutic target for asthma

High-mobility group box protein 1 (HMGB1) is a non-histone deoxyribonucleic acid-binding nuclear protein. In physiological state it is involved in gene transctioripn regulation and cell replication, differentiation and maturation. HMGB1 is actively secreted into the extracellular space in the form of intracellular vesicles, upon stimulation of inflammation and infection, by monocytes, macrophages, dendritic cells (DCs), and other immune cells, and can also be passively released by necrotic or injured cells. After binding with the corresponding receptors, HMGB1 can activate the downstream substrate and trigger a series of biological effects. HMGB1 was mainly dependent on toll-like re ceptors (TLR) 2 and 4, and receptors for advanced glycation end products (RAGE) to trigger intracellular signal transduction, and mediate innate and adoptive immune responses. Besides these, studies have reported the participation of TLR3, TLR9, T-cell immunoglobulin mucin (TIM) 3, CD24, anti-N-methyl-D-aspartate receptor (NMDAR) in Th2 inflammatory response, eosinophilic airway inflammation, and airway hyperresponsiveness, mediated by HMGB1 in asthma. Both clinical and experimental studies suggested that HMGB1 was involved in the pathogenesis of asthma probably by regulating the downstream signaling pathways via corresponding receptors. This article reviews the role of HMGB1 in pathogenesis of asthma, and provides a new theoretical basis for the diagnosis and treatment of asthma.

RAGE contributes to allergen driven severe neutrophilic airway inflammation via NLRP3 inflammasome activation in mice

Background

Asthma is a major public healthcare burden, affecting over 300 million people worldwide. While there has been great progress in the treatment of asthma, subsets of patients who present with airway neutrophilia, often have more severe disease, and tend to be resistant to conventional corticosteroid treatments. The receptor for advanced glycation endproducts (RAGE) plays a central role in the pathogenesis of eosinophilic asthma, however, it's role in neutrophilic asthma remains largely uninvestigated.

Methods

A mouse model of severe steroid resistant neutrophilic airway disease (SSRNAD) using the common fungal allergen Alternaria alternata (AA) was employed to evaluate the effects of genetic ablation of RAGE and pharmacological inhibition of the NLRP3 inflammasome on neutrophilic airway inflammation.

Results

AA exposure induced robust neutrophil-dominant airway inflammation and increased BALF levels of Th1/Th17 cytokines in wild-type mice, which was significantly reduced in RAGE^-/- mice. Serum levels of IgE and IgG1 were increased similarly in both wild-type and RAGE^-/- mice. Pharmacological inhibition of NLRP3 blocked the effects of AA exposure and NLRP3 inflammasome activation was RAGE-dependent. Neutrophil extracellular traps were elevated in the BALF of wild-type but not RAGE^-/- mice and an atypical population of SiglecF+ neutrophils were identified in the BALF. Lastly, time-course studies found that RAGE expression promoted sustained neutrophil accumulation in the BALF of mice in response to AA.

Oxidative Stress, Environmental Pollution, and Lifestyle as Determinants of Asthma in Children

Exposure to cigarette smoke, allergens, viruses, and other environmental contaminants, as well as a detrimental lifestyle, are the main factors supporting elevated levels of airway oxidative stress. Elevated oxidative stress results from an imbalance in reactive oxygen species (ROS) production and efficiency in antioxidant defense systems. Uncontrolled increased oxidative stress amplifies inflammatory processes and tissue damage and alters innate and adaptive immunity, thus compromising airway homeostasis. Oxidative stress events reduce responsiveness to corticosteroids. These events can increase risk of asthma into adolescence and prompt evolution of asthma toward its most severe forms. Development of new therapies aimed to restore oxidant/antioxidant balance and active interventions aimed to improve physical activity and quality/quantity of food are all necessary strategies to prevent asthma onset and avoid in asthmatics evolution toward severe forms of the disease.

Significant Interrelations among Serum Annexin A1, Soluble Receptor for Advanced Glycation End Products (sRAGE) and rs2070600 in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a major cause of death and morbidity; it may be accompanied by oxidative stress and inflammation with or without underlying genetic etiology. Finding circulating biomarkers for COPD that can help early diagnosis and predict exacerbation and association with respiratory functions has been challenging. There were 40 healthy participants and 60 COPD patients in this research. The rs2070600 gene variant was examined by PCR-RFLP. Circulating sRAGE and annexin A1 levels were determined by ELISA. GSH and MDA were determined by spectrophotometry. In COPD patients, sRAGE serum levels were substantially lower, but conversely, annexin A1 levels were much greater than in controls. The rs2070600 gene polymorphism's strong association with COPD was demonstrated by genotyping and allelic frequency distribution. The GA genotype was most distributed in COPD, and it was strongly linked to lower serum sRAGE levels. The interrelation between annexin A1, sRAGE, and COPD could be explained through effects on inflammatory mediators' pathways. The rs2070600 gene polymorphism was found to significantly enhance the risk of COPD. Serum sRAGE and annexin A1 may be considered potential diagnostic tools for COPD. Through impacts on GSH and MDA levels that alter the release of inflammatory factors and, therefore, lung damage, it is possible to explain the relationship between annexin A1, sRAGE, and COPD.

Sanzi Yangqin Decoction Alleviates Allergic Asthma by Modulating Th1/Th2 Balance: Coupling Network Pharmacology with Biochemical Pharmacology

This study aimed to verify that Sanzi Yangqin Decoction (SYD) can relieve asthma in mice and explore the effect on TH1/Th2 balance. The targets of SYD and asthma were explored from the public database using various methods. The potential targets and signaling pathways were identified by KEGG enrichment analysis from DAVID database. Mice asthma models were established using OVA and aluminum hydroxide. Lung tissues of mice were stained with HE and Masson. The contents of IFN-γ, IL-4, and TNF-α in BALF and IgE in mouse serum were detected using ELISA. In addition, the changes in Th1 and Th2 cells of the spleen were detected by flow cytometry. Fourteen core targets including IL4, IFNG, and MMP9 were identified for the treatment of asthma by SYD. The content of IL-4 in the lung tissue and BALF was gradually decreased with the increase in SYD concentration, while the IFN-γ was gradually increased. The drug significantly reduced IgE levels in serum and TNF-α in BALF. The number of Th1 cells in the spleen increased, while Th2 cells decreased in a concentration-dependent manner. SYD can alleviate pulmonary inflammation, restore Th1/Th2 balance, and relieve asthma.

AllergoOncology: Danger signals in allergology and oncology: A European Academy of Allergy and Clinical Immunology (EAACI) Position Paper

The immune system interacts with many nominal 'danger' signals, endogenous danger-associated (DAMP), exogenous pathogen (PAMP) and allergen (AAMP)-associated molecular patterns. The immune context under which these are received can promote or prevent immune activating or inflammatory mechanisms and may orchestrate diverse immune responses in allergy and cancer. Each can act either by favouring a respective pathology or by supporting the immune response to confer protective effects, depending on acuity or chronicity. In this Position Paper under the collective term danger signals or DAMPs, PAMPs and AAMPs, we consider their diverse roles in allergy and cancer and the connection between these in AllergoOncology. We focus on their interactions with different immune cells of the innate and adaptive immune system and how these promote immune responses with juxtaposing clinical outcomes in allergy and cancer. While danger signals present potential targets to overcome inflammatory responses in allergy, these may be reconsidered in relation to a history of allergy, chronic inflammation and autoimmunity linked to the risk of developing cancer, and with regard to clinical responses to anti-cancer immune and targeted therapies. Cross-disciplinary insights in AllergoOncology derived from dissecting clinical phenotypes of common danger signal pathways may improve allergy and cancer clinical outcomes.

Strongyloides venezuelensis-derived venestatin ameliorates asthma pathogenesis by suppressing receptor for advanced glycation end-products-mediated signaling

INTRODUCTION

EF-hand Ca²⁺-binding proteins such as S100 protein family members are recognized by the receptor for advanced glycation end-products (RAGE) and are involved in the pathogenesis of asthma/allergic airway inflammation (AAI). Venestatin, an EF-hand Ca²⁺-binding protein, which is secreted by the parasitic helminth Strongyloides venezuelensis, binds with RAGE and suppresses RAGE-mediated inflammatory responses after parasite invasion. In this study, we evaluated the effect of venestatin on pathogenesis in a house dust mite (HDM) murine model of asthma/AAI.

METHODS

Mice were intranasally treated with HDM, HDM with recombinant venestatin, or HDM with synthetic peptides, which were designed based on the EF-hand Ca²⁺-binding domain of venestatin. Pro-inflammatory responses in the lungs of mice were assessed.

RESULTS

HDM treatment induced inflammatory cell infiltration, phosphorylation of the mitogen-activated protein kinase and inhibitor κB, and production of the cytokines tumor necrosis factor-α and interleukin-5 in the lungs. Co-administration of recombinant venestatin with HDM suppressed these pro-inflammatory responses. Treatment with synthetic peptides reduced inflammatory cell infiltration in a RAGE-dependent manner.

CONCLUSION

The EF-hand domain of venestatin may have potential therapeutic benefits in asthma.

AllergoOncology: Role of immune cells and immune proteins

Background

Immune cells and immune proteins play a pivotal role in host responses to pathogens, allergens and cancer. Understanding the crosstalk between allergic response and cancer, immune surveillance, immunomodulation, role of immunoglobulin E (IgE)‐mediated functions and help to develop novel therapeutic strategies. Allergy and oncology show two opposite scenarios: whereas immune tolerance is desired in allergy, it is detrimental in cancer.

Aim

The current review provides an update on the role of immune cells and immune proteins in allergy and cancer fields.

Methods

Authors investigated the role of relevant immunological markers and the correlation with cancer progression or cancer suppression.

Results

Activated immune cells such as macrophages ‘M1’, dendritic cells (DCs), innate lymphoid cells (ILC2), NK cells, Th1, follicular T helper cells (TFH), TCD8+, B lymphocytes and eosinophils have inhibitory effects on tumourigenesis, while tolerogenic cells such as macrophages ‘M2,’ tolerogenic DCs, ILC3, T and B regulatory lymphocytes appear to favour carcinogenesis. Mastocytes and alarmins can have both effects. RIgE antibodies and CCCL5 chemokine have an anticancer role, whereas IgG4, free light chains, Il‐10, TGF‐β, lipocalin‐2, CCL1 chemokine promote cancer progression. Fundamental is also the contribution of epigenetic changes regulated by the microRNA in cancer progression.

Conclusion

This knowledge represents the key to developing new anticancer therapies.

Advances and highlights in biomarkers of allergic diseases

During the past years, there has been a global outbreak of allergic diseases, presenting a considerable medical and socioeconomical burden. A large fraction of allergic diseases is characterized by a type 2 immune response involving Th2 cells, type 2 innate lymphoid cells, eosinophils, mast cells, and M2 macrophages. Biomarkers are valuable parameters for precision medicine as they provide information on the disease endotypes, clusters, precision diagnoses, identification of therapeutic targets, and monitoring of treatment efficacies. The availability of powerful omics technologies, together with integrated data analysis and network‐based approaches can help the identification of clinically useful biomarkers. These biomarkers need to be accurately quantified using robust and reproducible methods, such as reliable and point‐of‐care systems. Ideally, samples should be collected using quick, cost‐efficient and noninvasive methods. In recent years, a plethora of research has been directed toward finding novel biomarkers of allergic diseases. Promising biomarkers of type 2 allergic diseases include sputum eosinophils, serum periostin and exhaled nitric oxide. Several other biomarkers, such as pro‐inflammatory mediators, miRNAs, eicosanoid molecules, epithelial barrier integrity, and microbiota changes are useful for diagnosis and monitoring of allergic diseases and can be quantified in serum, body fluids and exhaled air. Herein, we review recent studies on biomarkers for the diagnosis and treatment of asthma, chronic urticaria, atopic dermatitis, allergic rhinitis, chronic rhinosinusitis, food allergies, anaphylaxis, drug hypersensitivity and allergen immunotherapy. In addition, we discuss COVID‐19 and allergic diseases within the perspective of biomarkers and recommendations on the management of allergic and asthmatic patients during the COVID‐19 pandemic.

Advances and highlights in asthma in 2021

Last year brought a significant advance in asthma management, unyielding to the pressure of the pandemics. Novel key findings in asthma pathogenesis focus on the resident cell compartment, epigenetics and the innate immune system. The precision immunology unbiased approach was supplemented with novel tools and greatly facilitated by the use of artificial intelligence. Several randomised clinical trials and good quality real-world evidence shed new light on asthma treatment and supported the revision of several asthma guidelines (GINA, Expert Panel Report 3, ERS/ATS guidelines on severe asthma) and the conception of new ones (EAACI Guidelines for the use of biologicals in severe asthma). Integrating asthma management within the broader context of Planetary Health has been put forward. In this review, recently published articles and clinical trials are summarised and discussed with the goal to provide clinicians and researchers with a concise update on asthma research from a translational perspective.

Progranulin Protects Against Airway Remodeling Through the Modulation of Autophagy via HMGB1 Suppression in House Dust Mite-Induced Chronic Asthma

Purpose

Airway remodeling is an important feature of chronic asthma, and yet there are few effective therapeutic strategies. Progranulin (PGRN) has been shown to have lung protective functions, but the role of PGRN in asthmatic airway remodeling is unclear. We aim to explore the protective potential of PGRN on house dust mite (HDM)-induced airway remodeling and the underlying mechanisms.

Methods

In this study, a murine model of chronic asthma was established by HDM sensitization and challenge. Recombinant PGRN was intranasally administrated to mice during the phase of HDM challenge. TGF-β1-treated human airway epithelial BEAS-2B cells were utilized to explore the effect of PGRN on airway epithelia exposed to profibrotic conditions and molecular mechanisms.

Results

We found that PGRN treatment attenuated HDM-induced airway remodeling, as evidenced by the suppression of collagen accumulation, mucus overproduction and airway smooth muscle synthesis in HDM-challenged asthmatic mice lungs. Meanwhile, PGRN also reversed the increased levels of autophagy markers and autophagosomes in airway epithelia under mimic asthmatic conditions, thereby controlling the fibrotic process in vivo and in vitro. Specifically, overexpressed HMGB1 and the subsequent RAGE/MAPKs signaling activation due to HDM exposure were abrogated in PGRN-treated asthmatic mice. Furthermore, knockdown of HMGB1 expression significantly restrained the fibrosis formation in TGF-β1-induced airway epithelia accompanied by the downregulation of autophagic activity. However, enhancement of extracellular HMGB1 levels blunted the inhibition of autophagic flux by PGRN in airway epithelia, thereby resulting in the augmentation of collagen synthesis and fibrosis.

Conclusion

Taken together, our data revealed that PGRN protected against asthmatic airway remodeling by negatively regulating autophagy via HMGB1 suppression, which might provide new insights into the therapeutic options for HDM-induced chronic asthma.

Emerging Role of Phospholipase-Derived Cleavage Products in Regulating Eosinophil Activity: Focus on Lysophospholipids, Polyunsaturated Fatty Acids and Eicosanoids

Eosinophils are important effector cells involved in allergic inflammation. When stimulated, eosinophils release a variety of mediators initiating, propagating, and maintaining local inflammation. Both, the activity and concentration of secreted and cytosolic phospholipases (PLAs) are increased in allergic inflammation, promoting the cleavage of phospholipids and thus the production of reactive lipid mediators. Eosinophils express high levels of secreted phospholipase A2 compared to other leukocytes, indicating their direct involvement in the production of lipid mediators during allergic inflammation. On the other side, eosinophils have also been recognized as crucial mediators with regulatory and homeostatic roles in local immunity and repair. Thus, targeting the complex network of lipid mediators offer a unique opportunity to target the over-activation and 'pro-inflammatory' phenotype of eosinophils without compromising the survival and functions of tissue-resident and homeostatic eosinophils. Here we provide a comprehensive overview of the critical role of phospholipase-derived lipid mediators in modulating eosinophil activity in health and disease. We focus on lysophospholipids, polyunsaturated fatty acids, and eicosanoids with exciting new perspectives for future drug development.

Overlapping and distinct features of viral and allergen immunity in the human lung

Immunity in the human respiratory tract is provided by a diverse range of tissue-resident cells, including specialized epithelial and macrophage populations and a network of innate and innate-like lymphocytes, such as natural killer cells, innate lymphoid cells, and invariant T cells. Lung-resident memory T and B cells contribute to this network following initial exposure to antigenic stimuli. This review explores how advances in the study of human immunology have shaped our understanding of this resident immune network and its response to two of the most commonly encountered inflammatory stimuli in the airways: viruses and allergens. It discusses the many ways in which pathogenic infection and allergic inflammation mirror each other, highlighting the key checkpoints at which they diverge and how this can result in a lifetime of allergic exacerbation versus protective anti-viral immunity.