TLR-Stimulated Eosinophils Mediate Recruitment and Activation of NK Cells In Vivo

Membrane damage by MBP-1 is mediated by pore formation and amplified by mtDNA

Eosinophils play a crucial role in host defense while also contributing to immunopathology through the release of inflammatory mediators. Characterized by distinctive cytoplasmic granules, eosinophils securely store and rapidly release various proteins exhibiting high toxicity upon extracellular release. Among these, major basic protein 1 (MBP-1) emerges as an important mediator in eosinophil function against pathogens and in eosinophil-associated diseases. While MBP-1 targets both microorganisms and host cells, its precise mechanism remains elusive. We demonstrate that formation of small pores by MBP-1 in lipid bilayers induces membrane permeabilization and disrupts potassium balance. Additionally, we reveal that mitochondrial DNA (mtDNA) present in eosinophil extracellular traps (EETs) amplifies MBP-1 toxic effects, underscoring the pivotal role of mtDNA in EETs. Furthermore, we present evidence indicating that absence of CpG methylation in mtDNA contributes to the regulation of MBP-1-mediated toxicity. Taken together, our data suggest that the mtDNA scaffold within extracellular traps promotes MBP-1 toxicity.

α-FAtE: A new predictive score of response to atezolizumab plus bevacizumab for unresectable hepatocellular carcinoma

Atezolizumab plus bevacizumab (AB) and lenvatinib can be alternatively used as first-line systemic treatment of unresectable hepatocellular carcinoma (HCC). However, no direct comparison of the two regimens has been performed in randomized clinical trials, making the identification of baseline differential predictors of response of major relevance to tailor the best therapeutic option to each patient. Baseline clinical and laboratory characteristics of real-world AB-treated HCC patients were analyzed in uni- and multivariate analyses to find potential prognostic factors of overall survival (OS). Significant variables were incorporated in a composite score (α-FAtE) and it was tested for specificity and sensitivity in receiver operating characteristic (ROC) curve and in multivariate analysis for OS. The score was applied in uni- and multivariate analyses for OS of a comparable lenvatinib-treated HCC population. Finally, comparison between treatments was performed in patients with low and high α-FAtE scores and predictivity estimated by interaction analysis. Time-to-progression (TTP) was a secondary endpoint. OS of AB-treated HCC patients was statistically longer in those with α-fetoprotein <400 ng/mL (HR 0.62, p = .0407), alkaline phosphatase (ALP) <125 IU/L (HR 0.52, p = .0189) and eosinophil count ≥70/μL (HR 0.46, p = .0013). The α-FAtE score was generated by the sum of single points attributed to each variable among the above reported. In ROC curve analysis, superior sensitivity and specificity were achieved by the score compared to individual variables (AUC 0.794, p < .02). Patients with high score had longer OS (HR 0.44, p = .0009) and TTP (HR 0.34, p < .0001) compared to low score if treated with AB, but not with lenvatinib. Overall, AB was superior to lenvatinib in high score patients (HR 0.55, p = .0043) and inferior in low score ones (HR 1.75, p = .0227). At interaction test, low α-FAtE score resulted as negative predictive factor of response to AB (p = .0004). In conclusion, α-FAtE is a novel prognostic and predictive score of response to first-line AB for HCC patients that, if validated in prospective studies, could drive therapeutic choice between lenvatinib and AB.

An increased relative eosinophil count as a predictive dynamic biomarker in non-small cell lung cancer patients treated with immune checkpoint inhibitors

BACKGROUND

An increased relative eosinophil count (REC) has potential as a predictive biomarker for a beneficial clinical response and outcome to cancer immunotherapies. Therefore, the present study investigated the impact of an increased posttreatment REC on the prognosis of non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs).

METHODS

We retrospectively reviewed all 151 patients diagnosed with NSCLC and treated with ICI monotherapy and blood test data between March 2016 and August 2021 at National Hospital Organization Kochi Hospital and Tokushima University.

RESULTS

A total of 151 patients with a mean age of 69 years were included. REC after 4 weeks of initial ICI monotherapy was higher than pretreatment REC in 87 patients but not in 64. REC after 4 weeks of the ICI treatment with and without an increased REC were 4.4 and 1.8%, respectively (p < 0.001). Disease control rates (DCR) were significantly higher in patients with than in those without an increased REC (84% vs. 47%, p < 0.001). The median overall survival (OS) of lung cancer patients with or without an increased REC were 674 and 234 days, respectively. A Kaplan-Meier univariate analysis revealed a significant difference in OS between the two groups (p < 0.001). A Cox proportional regression analysis identified an increased REC as an independent predictor of OS (p = 0.003).

CONCLUSION

ICI-treated NSCLC patients with an increased REC after 4 weeks of treatment had a better DCR and prognosis than the other patients examined.

A risk signature based on endoplasmic reticulum stress-associated genes predicts prognosis and immunity in pancreatic cancer

Introduction: The involvement of endoplasmic reticulum (ER) stress in cancer biology is increasingly recognized, yet its role in pancreatic cancer (PC) remains unclear. This study aims to elucidate the impact of ER stress on prognosis and biological characteristics in PC patients. Methods: A bioinformatic analysis was conducted using RNA-seq data and clinicopathological information from PC patients in the TCGA and ICGC databases. The ER stress-associated gene sets were extracted from MSigDB. ER stress-associated genes closely linked with overall survival (OS) of PC patients were identified via log-rank test and univariate Cox analysis, and further narrowed by LASSO method. A risk signature associated with ER stress was formulated using multivariate Cox regression and assessed through Kaplan-Meier curves, receiver operating characteristic (ROC) analyses, and Harrell's concordance index. External validation was performed with the ICGC cohort. The single-sample gene-set enrichment analysis (ssGSEA) algorithm appraised the immune cell infiltration landscape. Results: Worse OS in PC patients with high-risk signature score was observed. Multivariate analysis underscored our ER stress-associated signature as a valuable and independent predictor of prognosis. Importantly, these results based on TCGA were further validated in ICGC dataset. In addition, our risk signature was closely associated with homeostasis, protein secretion, and immune regulation in PC patients. In particular, PC microenvironment in the high-risk cluster exhibited a more immunosuppressive status. At last, we established a nomogram model by incorporating the risk signature and clinicopathological parameters, which behaves better in predicting prognosis of PC patients. Discussion: This comprehensive molecular analysis presents a new predictive model for the prognosis of PC patients, highlighting ER stress as a potential therapeutic target. Besides, the findings indicate that ER stress can have effect modulating PC immune responses.

Basis of preventive and non-pharmacological interventions in asthma

Asthma is one of the most common atopic disorders in all stages of life. Its etiology is likely due to a complex interaction between genetic, environmental, and lifestyle factors. Due to this, different non-pharmacological interventions can be implemented to reduce or alleviate the symptoms caused by this disease. Thus, the present narrative review aimed to analyze the preventive and non-pharmacological interventions such as physical exercise, physiotherapy, nutritional, ergonutritional, and psychological strategies in asthma treatment. To reach these aims, an extensive narrative review was conducted. The databases used were MedLine (PubMed), Cochrane (Wiley), Embase, PsychINFO, and CinAhl. Asthma is an immune-mediated inflammatory condition characterized by increased responsiveness to bronchoconstrictor stimuli. Different factors have been shown to play an important role in the pathogenesis of asthma, however, the treatments used to reduce its incidence are more controversial. Physical activity is focused on the benefits that aerobic training can provide, while physiotherapy interventions recommend breathing exercises to improve the quality of life of patients. Nutritional interventions are targeted on implement diets that prioritize the consumption of fruits and vegetables and supplementation with antioxidants. Psychological interventions have been proposed as an essential non-pharmacological tool to reduce the emotional problems associated with asthma.

Targeting CXCL9/10/11-CXCR3 axis: an important component of tumor-promoting and antitumor immunity

Chemokines are chemotactic-competent molecules composed of a family of small cytokines, playing a key role in regulating tumor progression. The roles of chemokines in antitumor immune responses are of great interest. CXCL9, CXCL10, and CXCL11 are important members of chemokines. It has been widely investigated that these three chemokines can bind to their common receptor CXCR3 and regulate the differentiation, migration, and tumor infiltration of immune cells, directly or indirectly affecting tumor growth and metastasis. Here, we summarize the mechanism of how the CXCL9/10/11-CXCR3 axis affects the tumor microenvironment, and list the latest researches to find out how this axis predicts the prognosis of different cancers. In addition, immunotherapy improves the survival of tumor patients, but some patients show drug resistance. Studies have found that the regulation of CXCL9/10/11-CXCR3 on the tumor microenvironment is involved in the process of changing immunotherapy resistance. Here we also describe new approaches to restoring sensitivity to immune checkpoint inhibitors through the CXCL9/10/11-CXCR3 axis.

Identification of the Characteristic Genes and their Roles in Lung Adenocarcinoma Lymph Node Metastasis through Machine Learning Algorithm

Background. Lymph node metastasis is an important route of lung cancer metastasis and can significantly affect the survival of lung cancer. Methods. All the analysis was conducted out in the R software. Expression profile and clinical information of lung adenocarcinoma (LUAD) patients were downloaded from The Cancer Genome Atlas database. Results. In our study, we firstly identified the characteristic genes of lymph node metastasis in LUAD through two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) logistic regression, and SVM-RFE algorithms. Ten characteristic genes were finally identified, including CRHR2, ITIH1, PRSS48, MAS1L, CYP4Z1, LMO1, TCP10L2, KRT78, IGFBP1, and PITX3. Next, we performed univariate Cox regression, LASSO regression, and multivariate Cox regression sequentially to construct a prognosis model based on MAS1L, TCP10L2, and CRHR2, which had a good prognosis prediction efficiency in both training and validation cohorts. Univariate and multivariate analysis indicated that our model is a risk factor independent of other clinical features. Pathway enrichment analysis showed that in the high-risk patients, the pathway of MYC target, unfolded protein response, interferon alpha response, DNA repair, reactive oxygen species pathway, and glycolysis were significantly enriched. Among three model genes, MAS1L aroused our interest and therefore was selected for further analysis. KM survival curves showed that the patients with higher MAS1L might have better disease-free survival and progression-free survival. Further, pathway enrichment, genomic instability, immune infiltration, and drug sensitivity analysis were performed to in-deep explore the role of MAS1L in LUAD. Conclusions. Results showed that the signature based on MAS1L, TCP10L2, and CRHR2 is a useful tool to predict prognosis and lung cancer lymph node metastasis.

Eosinophil-lymphocyte interactions in the tumor microenvironment and cancer immunotherapy

Eosinophils are important effector cells and therapeutic targets in allergic diseases. Emerging data indicate that eosinophils infiltrate a variety of solid tumor types and have pleiotropic activities by at least two non-mutually exclusive mechanisms: direct interactions with tumor cells, and intricate cross-talk with lymphocytes. In light of the immune checkpoint inhibition revolution in cancer therapy, we review eosinophil-lymphocyte interactions in the tumor microenvironment. We also analyze potential interactions between eosinophils and lymphocyte subsets, including T cells, natural killer cells and innate lymphoid cells. We provide perspectives on the consequences of these interactions and how eosinophils are accessory cells that can affect the response to various forms of T cell-mediated immunotherapies and might be therapeutically targeted to improve cancer immunotherapy.

Eosinophils and Lung Cancer: From Bench to Bedside

Eosinophils are rare, multifunctional granulocytes. Their growth, survival, and tissue migration mainly depend on interleukin (IL)-5 in physiological conditions and on IL-5 and IL-33 in inflammatory conditions. Preclinical evidence supports an immunological role for eosinophils as innate immune cells and as agents of the adaptive immune response. In addition to these data, several reports show a link between the outcomes of patients treated with immune checkpoint inhibitors (ICI) for advanced cancers and blood eosinophilia. In this review, we present, in the context of non-small cell lung cancer (NSCLC), the biological properties of eosinophils and their roles in homeostatic and pathological conditions, with a focus on their pro- and anti-tumorigenic effects. We examine the possible explanations for blood eosinophilia during NSCLC treatment with ICI. In particular, we discuss the value of eosinophils as a potential prognostic and predictive biomarker, highlighting the need for stronger clinical data. Finally, we conclude with perspectives on clinical and translational research topics on this subject.

Short-term IL-15 priming leaves a long-lasting signalling imprint in mouse NK cells independently of a metabolic switch

NK cell reactivity is dynamically regulated by IL-15, and NK cells do not need more than a few minutes of exposure to remember the cytokine for several hours.

IL-15 priming of NK cells is a broadly accepted concept, but the dynamics and underlying molecular mechanisms remain poorly understood. We show that as little as 5 min of IL-15 treatment in vitro, followed by removal of excess cytokines, results in a long-lasting, but reversible, augmentation of NK cell responsiveness upon activating receptor cross-linking. In contrast to long-term stimulation, improved NK cell function after short-term IL-15 priming was not associated with enhanced metabolism but was based on the increased steady-state phosphorylation level of signalling molecules downstream of activating receptors. Inhibition of JAK3 eliminated this priming effect, suggesting a cross talk between the IL-15 receptor and ITAM-dependent activating receptors. Increased signalling molecule phosphorylation levels, calcium flux, and IFN-γ secretion lasted for up to 3 h after IL-15 stimulation before returning to baseline. We conclude that IL-15 rapidly and reversibly primes NK cell function by modulating activating receptor signalling. Our findings suggest a mechanism by which NK cell reactivity can potentially be maintained in vivo based on only brief encounters with IL-15 trans-presenting cells.

BCG Therapy of Bladder Cancer Stimulates a Prolonged Release of the Chemoattractant CXCL10 (IP10) in Patient Urine

Background: Intra-vesical instillation of Bacille Calmette–Guérin (BCG), an attenuated strain of Mycobacterium bovis, is an effective therapy for high-grade non-muscle invasive bladder cancer (NMIBC), which provokes a local immune response resulting in 70% of patients free of relapse after three years. Because non-responder patients usually have a bad prognosis, the early identification of treatment failure is crucial. We hypothesized that, if an effective immune response was taking place in the bladder, soluble factors would be released to the urine many days after BCG instillations. Methods: An extensive panel of cytokines and chemokines released into the urine seven days after every BCG instillation was screened in a cohort of NMIBC patients over three years. Results: The determinations of the urinary concentrations of cytokines, chemokines, and creatinine showed that increasing concentrations of C-X-C motif chemokine 10 (CXCL10) also known as interferon-inducible protein 10 (IP10) could be detected during the six-week induction cycle of BCG-treated patients released into the urine by CD14⁺ cells. In vitro, CXCL10 facilitated the recruitment of effector immune cells after the BCG-mediated upregulation of CXCR3 in both T- and natural killer (NK)-cells. Conclusions: The high concentrations of chemokine detected one week after the encounter with mycobacteria suggest that the CXCL10 axis might be related to the intensity of the immune anti-tumor response.

Opposing roles of eosinophils in cancer

Eosinophils are a subset of granulocytes mostly known for their ability to combat parasites and induce allergy. Although they were described to be related to cancer more than 100 years ago, their role in tumors is still undefined. Recent observations revealed that they display regulatory functions towards other immune cell subsets in the tumor microenvironment or direct cytotoxic functions against tumor cells, leading to either antitumor or protumor effects. This paradoxical role of eosinophils was suggested to be dependent on the different factors in the TME. In addition, the clinical relevance of these cells has been recently addressed. In most cases, the accumulation of eosinophils both in the tumor tissue, called tumor-associated tissue eosinophilia, and in the peripheral blood were reported to be prognostic markers for a better outcome of cancer patients. In immunotherapy of cancer, particularly in therapy with immune checkpoint inhibitors, eosinophils were even shown to be a potential predictive marker for a beneficial clinical response. A better understanding of their role in cancer progression will help to establish them as prognostic and predictive markers and to design strategies for targeting eosinophils.

Impact of eosinophil-peroxidase (EPX) deficiency on eosinophil structure and function in mouse airways

Eosinophil peroxidase (EPX) is a major constituent of the large cytoplasmic granules of both human and mouse eosinophilic leukocytes. Human EPX deficiency is a rare, autosomal-recessive disorder limited to the eosinophil lineage. Our intent was to explore the impact of EPX gene deletion on eosinophil content, structure, and function. In response to repetitive intranasal challenge with a filtrate of the allergen, Alternaria alternata, we found significantly fewer eosinophils peripherally and in the respiratory tracts of EPX^-/- mice compared to wild-type controls; furthermore, both the major population (Gr1^-/lo ) and the smaller population of Gr1^hi eosinophils from EPX^-/- mice displayed lower median fluorescence intensities (MFIs) for Siglec F. Quantitative evaluation of transmission electron micrographs of lung eosinophils confirmed the relative reduction in granule outer matrix volume in cells from the EPX^-/- mice, a finding analogous to that observed in human EPX deficiency. Despite the reduced size of the granule matrix, the cytokine content of eosinophils isolated from allergen-challenged EPX^{-/ -} and wild-type mice were largely comparable to one another, although the EPX^-/- eosinophils contained reduced concentrations of IL-3. Other distinguishing features of lung eosinophils from allergen-challenged EPX^-/- mice included a reduced fraction of surface TLR4⁺ cells and reduced MFI for NOD1. Interestingly, the EPX gene deletion had no impact on eosinophil-mediated clearance of gram-negative Haemophilus influenzae from the airways. As such, although no clinical findings have been associated with human EPX deficiency, our findings suggest that further evaluation for alterations in eosinophil structure and function may be warranted.

Oxidative stress and cellular pathways of asthma and inflammation: Therapeutic strategies and pharmacological targets

Asthma is a complex inflammatory disease characterized by airway inflammation and hyperresponsiveness. The mechanisms associated with the development and progression of asthma have been widely studied in multiple populations and animal models, and these have revealed involvement of various cell types and activation of intracellular signaling pathways that result in activation of inflammatory genes. Significant contributions of Toll-like-receptors (TLRs) and transcription factors such as NF-кB, have been reported as major contributors to inflammatory pathways. These have also recently been associated with mechanisms of oxidative biology. This is of important clinical significance as the observed inefficacy of current available treatments for severe asthma is widely attributed to oxidative stress. Therefore, targeting oxidizing molecules in conjunction with inflammatory mediators and transcription factors may present a novel therapeutic strategy for asthma. In this review, we summarize TLRs and NF-кB pathways in the context of exacerbation of asthma pathogenesis and oxidative biology, and we discuss the potential use of polyphenolic flavonoid compounds, known to target these pathways and possess antioxidant activity, as potential therapeutic agents for asthma.

Eosinophils: The unsung heroes in cancer?

Prolonged low-grade inflammation or smoldering inflammation is a hallmark of a cancer. Eosinophils are components of the immune microenvironment that modulates tumor initiation and progression. Although canonically associated with a detrimental role in allergic disorders, these cells can induce a protective immune response against helminthes, viral and bacterial pathogens. Eosinophils are a source of anti-tumorigenic (e.g., TNF-α, granzyme, cationic proteins, and IL-18) and protumorigenic molecules (e.g., pro-angiogenic factors) depending on the milieu. In several neoplasias (e.g., melanoma, gastric, colorectal, oral and prostate cancer) eosinophils play an anti-tumorigenic role, in others (e.g., Hodgkin's lymphoma, cervical carcinoma) have been linked to poor prognosis, whereas in yet others they are apparently innocent bystanders. These seemingly conflicting results suggest that the role of eosinophils and their mediators could be cancer-dependent. The microlocalization (e.g., peritumoral vs intratumoral) of eosinophils could be another important aspect in the initiation/progression of solid and hematological tumors. Increasing evidence in experimental models indicates that activation/recruitment of eosinophils could represent a new therapeutic strategy for certain tumors (e.g., melanoma). Many unanswered questions should be addressed before we understand whether eosinophils are an ally, adversary or neutral bystanders in different types of human cancers.