Targeting eosinophils in respiratory diseases: Biological axis, emerging therapeutics and treatment modalities

Biologics for asthma and risk of pneumonia

OBJECTIVE

Modification of the immune system with biologics raises theoretical concerns about the risk of infections but it is still unclear whether currently routinely used biologics in severe asthma may facilitate the development of pneumonia. Therefore, we aimed to determine whether omalizumab, mepolizumab, benralizumab, and dupilumab are associated with pneumonia in a real-world setting.

METHODS

A retrospective disproportionality analysis was performed using adverse event (AE) reports submitted to FAERS from January 2020 to September 30, 2023. MedDRA was used to identify infections and infestations and then pneumonia cases. ROR and PRR were used to measure disproportionality.

RESULTS

The percentage of reported cases of pneumonia compared to infections and infestations was highest for mepolizumab (36.8%), followed by omalizumab (32.6%), benralizumab (19.2%) and dupilumab (5.7%). We found a moderate or strong signal for increased risk of pneumonia with mepolizumab (ROR = 3.74, 95%CI 3.50-4.00), omalizumab (ROR = 3.26, 95%CI 3.06-3.49) and benralizumab (ROR = 2.65, 95%CI 2.49-2.83).

CONCLUSIONS

Mepolizumab, omalizumab and benralizumab, but not dupilumab, were associated with high odds of reporting pneumonia. Our results represent only potential associations between these biologics and pneumonia but not causality. The nature of the FAERS database is such that the cause of the reported events is uncertain. Therefore, we can only roughly estimate the incidence of AEs by the signal strength (ROR value). Nevertheless, although causality could not be assessed, the signal from our study is interesting. We believe it deserves to be further substantiated by real-world studies with robust designs.

Eosinophils and Cognitive Impairment in Schizophrenia: A New Perspective

Schizophrenia is a complex psychiatric disorder characterized by a wide array of cognitive impairments. While research has predominantly focused on the neurological aspects of schizophrenia, emerging evidence suggests that the immune system, specifically eosinophils, may play a significant role in the cognitive deficits associated with the disorder. This review presents a novel perspective on the interplay between eosinophils and cognitive impairment in schizophrenia. Eosinophils, traditionally associated with allergic responses and inflammation, have garnered limited attention within the realm of neuropsychiatry. Recent studies have hinted at a potential link between eosinophil activation and the pathogenesis of schizophrenia. In this comprehensive review, we delve into the world of eosinophils, elucidating their nature, functions, and interactions with the immune system. We examine the cognitive deficits observed in individuals with schizophrenia and discuss existing theories on the etiology of these impairments, focusing on immune system involvement. The paper also highlights the evolving body of research that supports the idea of eosinophilic influence on schizophrenia-related cognitive deficits. Furthermore, we explore potential mechanisms through which eosinophils may exert their effects on cognitive function in schizophrenia, including interactions with other immune cells and inflammatory pathways. By discussing the clinical implications and potential therapeutic avenues stemming from this newfound perspective, we underscore the practical significance of this emerging field of research. While this paper acknowledges the limitations and challenges inherent in studying eosinophils within the context of schizophrenia, it serves as a posit for novel thought in this vexing disease space as well as a call to action for future research endeavors. By providing a comprehensive survey of the existing literature and posing unanswered questions, we aim to inspire a reimagining of the relationship between eosinophils and cognitive impairment in schizophrenia, ultimately advancing our understanding and treatment of this debilitating disorder.

A comprehensive review on the emerging role of long non-coding RNAs in the regulation of NF-κB signaling in inflammatory lung diseases

Public health globally faces significant risks from conditions like acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and various inflammatory lung disorders. The NF-κB signaling system partially controls lung inflammation, immunological responses, and remodeling. Non-coding RNAs (lncRNAs) are crucial in regulating gene expression. They are increasingly recognized for their involvement in NF-κB signaling and the development of inflammatory lung diseases. Disruption of lncRNA-NF-κB interactions is a potential cause and resolution factor for inflammatory respiratory conditions. This study explores the therapeutic potential of targeting lncRNAs and NF-κB signaling to alleviate inflammation and restore lung function. Understanding the intricate relationship between lncRNAs and NF-κB signaling could offer novel insights into disease mechanisms and identify therapeutic targets. Regulation of lncRNAs and NF-κB signaling holds promise as an effective approach for managing inflammatory lung disorders. This review aims to comprehensively analyze the interaction between lncRNAs and the NF-κB signaling pathway in the context of inflammatory lung diseases. It investigates the functional roles of lncRNAs in modulating NF-κB activity and the resulting inflammatory responses in lung cells, focusing on molecular mechanisms involving upstream regulators, inhibitory proteins, and downstream effectors.

Uncovering the complex role of interferon-gamma in suppressing type 2 immunity to cancer

Cancer involves cells' abnormal growth and ability to invade or metastasize to different body parts. Cancerous cells can divide uncontrollably and spread to other areas through the lymphatic or circulatory systems. Tumors form when malignant cells clump together in an uncontrolled manner. In this context, the cytokine interferon-gamma (IFN-γ) is crucial in regulating immunological responses, particularly malignancy. While IFN-γ is well-known for its potent anti-tumor effects by activating type 1 immunity, recent research has revealed its ability to suppress type 2 immunity, associated with allergy and inflammatory responses. This review aims to elucidate the intricate function of IFN-γ in inhibiting type 2 immune responses to cancer. We explore how IFN-γ influences the development and function of immune cells involved in type 2 immunity, such as mast cells, eosinophils, and T-helper 2 (Th2) cells. Additionally, we investigate the impact of IFN-mediated reduction of type 2 immunity on tumor development, metastasis, and the response to immunotherapeutic interventions. To develop successful cancer immunotherapies, it is crucial to comprehend the complex interplay between type 2 and type 1 immune response and the regulatory role of IFN-γ. This understanding holds tremendous promise for the development of innovative treatment approaches that harness the abilities of both immune response types to combat cancer. However, unraveling the intricate interplay between IFN-γ and type 2 immunity in the tumor microenvironment will be essential for achieving this goal.

Angiogenesis, Lymphangiogenesis, and Inflammation in Chronic Obstructive Pulmonary Disease (COPD): Few Certainties and Many Outstanding Questions

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, predominantly affecting the lung parenchyma and peripheral airways, that results in progressive and irreversible airflow obstruction. COPD development is promoted by persistent pulmonary inflammation in response to several stimuli (e.g., cigarette smoke, bacterial and viral infections, air pollution, etc.). Angiogenesis, the formation of new blood vessels, and lymphangiogenesis, the formation of new lymphatic vessels, are features of airway inflammation in COPD. There is compelling evidence that effector cells of inflammation (lung-resident macrophages and mast cells and infiltrating neutrophils, eosinophils, basophils, lymphocytes, etc.) are major sources of a vast array of angiogenic (e.g., vascular endothelial growth factor-A (VEGF-A), angiopoietins) and/or lymphangiogenic factors (VEGF-C, -D). Further, structural cells, including bronchial and alveolar epithelial cells, endothelial cells, fibroblasts/myofibroblasts, and airway smooth muscle cells, can contribute to inflammation and angiogenesis in COPD. Although there is evidence that alterations of angiogenesis and, to a lesser extent, lymphangiogenesis, are associated with COPD, there are still many unanswered questions.

Therapeutic Potential for Intractable Asthma by Targeting L-Type Amino Acid Transporter 1

Bronchial asthma is a chronic disease characterized by airway inflammation, obstruction, and hyperresponsiveness. CD4⁺ T cells, particularly T helper (Th) 2 cells, and their specific cytokines are important mediators in asthma pathogenesis. However, it has been established that Th subsets, other than Th2, as well as various cell types, including innate lymphoid cells (ILCs), significantly contribute to the development of allergic inflammation. These cells require facilitated amino acid uptake to ensure their full function upon activation. Emerging studies have suggested the potential of pharmacological inhibition of amino acid transporters to inhibit T cell activation and the application of this strategy for treating immunological and inflammatory disorders. In the present review, we explore the possibility of targeting L-type amino acid transporter (LAT) as a novel therapeutic approach for bronchial asthma, including its steroid-resistant endotypes.

Meta-analysis of transcriptional regulatory networks for lipid metabolism in neural cells from schizophrenia patients based on an open-source intelligence approach

There have been a number of reports about the transcriptional regulatory networks in schizophrenia. However, most of these studies were based on a specific transcription factor or a single dataset, an approach that is inadequate to understand the diverse etiology and underlying common characteristics of schizophrenia. Here we reconstructed and compared the transcriptional regulatory network for lipid metabolism enzymes using 15 public transcriptome datasets of neural cells from schizophrenia patients. Since many of the well-known schizophrenia-related SNPs are in enhancers, we reconstructed a network including enhancer-dependent regulation and found that 53.3 % of the total number of edges (7,577 pairs) involved regulation via enhancers. By examining multiple datasets, we found common and unique transcriptional modes of regulation. Furthermore, enrichment analysis of SNPs that were connected with genes in the transcriptional regulatory networks by eQTL suggested an association with hematological cell counts and some other traits/diseases, whose relationship to schizophrenia was either not or insufficiently reported in previous studies. Based on these results, we suggest that in future studies on schizophrenia, information on genotype, comorbidities and hematological cell counts should be included, along with the transcriptome, for a more detailed genetic stratification and mechanistic exploration of schizophrenia.

Development and evaluation of the effect of ethanol and surfactant in vesicular carriers on Lamivudine permeation through the skin

The skin embodies a relatively large and readily accessible surface area to absorb a drug through a non-invasive procedure. The vesicular carrier systems such as liposomes, ethosomes, and transethosomes have been explored as non-invasive systems for transdermal delivery of drugs. In the present study, different vesicular carriers were prepared by the thin-film hydration method with modification, and various parameters like size, elasticity, and release profiles were evaluated. Ethosomes and transethosomes have shown the smaller size of 362.21 ± 55.76 and 314.34 ± 41.21 nm, with deformity of 19.34% and 25.04%, respectively, compared with liposomes. The FTIR study of the skin before and after the application of vesicular formulation was performed. The ethosomes and transethosomes changed the orthorhombic phase to the liquid crystalline phase to move the vesicular carrier with the drug to cross the stratum corneum (SC) of the skin. The thermotropic behaviour of drug and vesicular carrier ingredients was studied using differential scanning calorimetry (DSC). Fluorescence images of vesicular-skin permeation have revealed that ethosome and transethosome formulation have shown deeper penetration across the SC and epidermis. The in vitro drug release from the ethosomes and transethosomes has shown 93.34 ± 1.23% and 95.45 ± 2.67% of drug release using Franz diffusion cell and porcine skin as a membrane. The nanostructured flexible vesicular carrier containing ethanol alone and a combination of ethanol and edge activator is a perfect carrier for drug penetration to the deeper skin layer and maintaining the sustained release of drug for a prolonged time.

Interleukin-13: A pivotal target against influenza-induced exacerbation of chronic lung diseases

Non-communicable, chronic respiratory diseases (CRDs) affect millions of individuals worldwide. The course of these CRDs (asthma, chronic obstructive pulmonary disease, and cystic fibrosis) are often punctuated by microbial infections that may result in hospitalization and are associated with increased risk of morbidity and mortality, as well as reduced quality of life. Interleukin-13 (IL-13) is a key protein that regulates airway inflammation and mucus hypersecretion. There has been much interest in IL-13 from the last two decades. This cytokine is believed to play a decisive role in the exacerbation of inflammation during the course of viral infections, especially, in those with pre-existing CRDs. Here, we discuss the common viral infections in CRDs, as well as the potential role that IL-13 plays in the virus-induced disease pathogenesis of CRDs. We also discuss, in detail, the immune-modulation potential of IL-13 that could be translated to in-depth studies to develop IL-13-based therapeutic entities.

Beyond Il-5: Metabolic Reprogramming and Stromal Support Are Prerequisite for Generation and Survival of Long-Lived Eosinophil

Eosinophils play surprisingly diverse roles in health and disease. Accordingly, we have now begun to appreciate the scope of the functional and phenotypic heterogeneity and plasticity of these cells. Along with tissue-recruited subsets during inflammation, there are tissue resident eosinophil phenotypes with potentially longer life spans and less dependency on IL-5 for survival. Current models to study murine eosinophils ex vivo rely on IL-5-sustained expansion of eosinophils from bone marrow hematopoietic progenitors. Although it does generate eosinophils (bmEos) in high purity, such systems are short-lived (14 days on average) and depend on IL-5. In this report, we present a novel method of differentiating large numbers of pure bone marrow-derived eosinophils with a long-lived phenotype (llEos) (40 days on average) that require IL-5 for initial differentiation, but not for subsequent survival. We identified two key factors in the development of llEos: metabolic adaptation and reprogramming induced by suppressed nutrient intake during active differentiation (from Day 7 of culture), and interaction with IL-5-primed stromal cells for the remainder of the protocol. This regimen results in a higher yield and viability of mature eosinophils. Phenotypically, llEos develop as Siglec-F(+)Ly6G(+) cells transitioning to Siglec-F(+) only, and exhibit typical eosinophil features with red eosin granular staining, as well as the ability to chemotax to eotaxin Ccl11 and process fibrinogen. This culture system requires less reagent input and allows us to study eosinophils long-term, which is a significant improvement over IL-5-driven differentiation protocols. Moreover, it provides important insights into factors governing eosinophil plasticity and the ability to assume long-lived IL-5-independent phenotypes.

Heterogeneity of Intestinal Tissue Eosinophils: Potential Considerations for Next-Generation Eosinophil-Targeting Strategies

Eosinophils are implicated in the pathophysiology of a spectrum of eosinophil-associated diseases, including gastrointestinal eosinophilic diseases (EGIDs). Biologics that target the IL-5 pathway and are intended to ablate eosinophils have proved beneficial in severe eosinophilic asthma and may offer promise in treating some endotypes of EGIDs. However, destructive effector functions of eosinophils are only one side of the coin; eosinophils also play important roles in immune and tissue homeostasis. A growing body of data suggest tissue eosinophils represent a plastic and heterogeneous population of functional sub-phenotypes, shaped by environmental (systemic and local) pressures, which may differentially impact disease outcomes. This may be particularly relevant to the GI tract, wherein the highest density of eosinophils reside in the steady state, resident immune cells are exposed to an especially broad range of external and internal environmental pressures, and greater eosinophil longevity may uniquely enrich for co-expression of eosinophil sub-phenotypes. Here we review the growing evidence for functional sub-phenotypes of intestinal tissue eosinophils, with emphasis on the multifactorial pressures that shape and diversify eosinophil identity and potential targets to inform next-generation eosinophil-targeting strategies designed to restrain inflammatory eosinophil functions while sustaining homeostatic roles.