T helper 2 cells control monocyte to tissue-resident macrophage differentiation during nematode infection of the pleural cavity.

The recent revolution in tissue-resident macrophage biology has resulted largely from murine studies performed in C57BL/6 mice. Here, using both C57BL/6 and BALB/c mice, we analyze immune cells in the pleural cavity. Unlike C57BL/6 mice, naive tissue-resident large-cavity macrophages (LCMs) of BALB/c mice failed to fully implement the tissue-residency program. Following infection with a pleural-dwelling nematode, these pre-existing differences were accentuated with LCM expansion occurring in C57BL/6, but not in BALB/c mice. While infection drove monocyte recruitment in both strains, only in C57BL/6 mice were monocytes able to efficiently integrate into the resident pool. Monocyte-to-macrophage conversion required both T cells and interleukin-4 receptor alpha (IL-4Rα) signaling. The transition to tissue residency altered macrophage function, and GATA6+ tissue-resident macrophages were required for host resistance to nematode infection. Therefore, during tissue nematode infection, T helper 2 (Th2) cells control the differentiation pathway of resident macrophages, which determines infection outcome.

Engineering the IL-4/IL-13 axis for targeted immune modulation.

The structurally and functionally related interleukin-4 (IL-4) and IL-13 cytokines play pivotal roles in shaping immune activity. The IL-4/IL-13 axis is best known for its critical role in T helper 2 (Th2) cell-mediated Type 2 inflammation, which protects the host from large multicellular pathogens, such as parasitic helminth worms, and regulates immune responses to allergens. In addition, IL-4 and IL-13 stimulate a wide range of innate and adaptive immune cells, as well as non-hematopoietic cells, to coordinate various functions, including immune regulation, antibody production, and fibrosis. Due to its importance for a broad spectrum of physiological activities, the IL-4/IL-13 network has been targeted through a variety of molecular engineering and synthetic biology approaches to modulate immune behavior and develop novel therapeutics. Here, we review ongoing efforts to manipulate the IL-4/IL-13 axis, including cytokine engineering strategies, formulation of fusion proteins, antagonist development, cell engineering approaches, and biosensor design. We discuss how these strategies have been employed to dissect IL-4 and IL-13 pathways, as well as to discover new immunotherapies targeting allergy, autoimmune diseases, and cancer. Looking ahead, emerging bioengineering tools promise to continue advancing fundamental understanding of IL-4/IL-13 biology and enabling researchers to exploit these insights to develop effective interventions.

Epidermal Growth Factor Receptor Expression Licenses Type-2 Helper T Cells to Function in a T Cell Receptor-Independent Fashion.

Gastro-intestinal helminth infections trigger the release of interleukin-33 (IL-33), which induces type-2 helper T cells (Th2 cells) at the site of infection to produce IL-13, thereby contributing to host resistance in a T cell receptor (TCR)-independent manner. Here, we show that, as a prerequisite for IL-33-induced IL-13 secretion, Th2 cells required the expression of the epidermal growth factor receptor (EGFR) and of its ligand, amphiregulin, for the formation of a signaling complex between T1/ST2 (the IL-33R) and EGFR. This shared signaling complex allowed IL-33 to induce the EGFR-mediated activation of the MAP-kinase signaling pathway and consequently the expression of IL-13. Lack of EGFR expression on T cells abrogated IL-13 expression in infected tissues and impaired host resistance. EGFR expression on Th2 cells was TCR-signaling dependent, and therefore, our data reveal a mechanism by which antigen presentation controls the innate effector function of Th2 cells at the site of inflammation.

Highly pathogenic PRRSV upregulates IL-13 production through nonstructural protein 9-mediated inhibition of N6-methyladenosine demethylase FTO.

Porcine reproductive and respiratory syndrome virus (PRRSV), a highly infectious virus, causes severe losses in the swine industry by regulating the inflammatory response, inducing tissue damage, suppressing the innate immune response, and promoting persistent infection in hosts. Interleukin-13 (IL-13) is a cytokine that plays a critical role in regulating immune responses and inflammation, particularly in immune-related disorders, certain types of cancer, and numerous bacterial and viral infections; however, the underlying mechanisms of IL-13 regulation during PRRSV infection are not well understood. In this study, we demonstrated that PRRSV infection elevates IL-13 levels in porcine alveolar macrophages. PRRSV enhances m6A-methylated RNA levels while reducing the expression of fat mass and obesity associated protein (FTO, an m6A demethylase), thereby augmenting IL-13 production. PRRSV nonstructural protein 9 (nsp9) was a key factor for this modulation. Furthermore, we found that the residues Asp567, Tyr586, Leu593, and Asp595 were essential for nsp9 to induce IL-13 production via attenuation of FTO expression. These insights delineate PRRSV nsp9's role in FTO-mediated IL-13 release, advancing our understanding of PRRSV's impact on host immune and inflammatory responses.

German cockroach extract prevents IL-13-induced CCL26 expression in airway epithelial cells through IL-13 degradation.

Inhaled aeroallergens can directly activate airway epithelial cells (AECs). Exposure to cockroach allergens is a strong risk factor for asthma. Cockroach allergens mediate some of their effects through their serine protease activity; protease activity is also a major contributor to allergenicity. The Th2 cytokine interleukin-13 (IL-13) induces upregulation of the eosinophil chemotactic factor CCL26. CCL26 induces eosinophil migration in allergic inflammation. In this work, we studied the effect of cockroach proteases on IL-13-induced effects. Immersed cultures of the human bronchial epithelial cell line BEAS-2B and air-liquid interface (ALI) cultures of primary normal human bronchial epithelial (NHBE) cells were stimulated with IL-13, Blattella Germanica cockroach extract (CE), or both. IL-13-induced genes were analyzed with qRT-PCR. IL-13 induced upregulation of CCL26, periostin, and IL-13Rα2 in bronchial epithelial cells which were decreased by CE. CE was heat-inactivated (HICE) or pre-incubated with protease inhibitors. HICE and CE preincubated with serine protease inhibitors did not prevent IL-13-induced CCL26 upregulation. CE-degraded IL-13 and specific cleavage sites were identified. CE also decreased IL-4-induced CCL26 upregulation and degraded IL-4. Other serine proteases such as bovine trypsin and house dust mite (HDM) serine proteases did not have the same effects on IL-13-induced CCL26. We conclude that CE serine proteases antagonize IL-13-induced effects in AECs, and this CE effect is mediated primarily through proteolytic cleavage of IL-13. IL-13 cleavage by cockroach serine proteases may modulate CCL26-mediated effects in allergic airway inflammation by interfering directly with the pro-inflammatory effects of IL-13 in vivo.

IL-4Rα signaling promotes barrier-altering oncostatin M and IL-6 production in aspirin-exacerbated respiratory disease.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is a severe disease involving dysregulated type 2 inflammation. However, the role other inflammatory pathways play in AERD is poorly understood. OBJECTIVE: We sought to broadly define the inflammatory milieu of the upper respiratory tract in AERD and to determine the effects of IL-4Rα inhibition on mediators of nasal inflammation. METHODS: Twenty-two AERD patients treated with dupilumab for 3 months were followed over 3 visits and compared to 10 healthy controls. Nasal fluid was assessed for 45 cytokines and chemokines using Olink Target 48. Blood neutrophils and cultured human mast cells, monocytes/macrophages, and nasal fibroblasts were assessed for response to IL-4/13 stimulation in vitro. RESULTS: Of the nasal fluid cytokines measured, nearly one third were higher in AERD patients compared to healthy controls, including IL-6 and the IL-6 family-related cytokine oncostatin M (OSM), both of which correlated with nasal albumin levels, a marker of epithelial barrier dysregulation. Dupilumab significantly decreased many nasal mediators, including OSM and IL-6. IL-4 stimulation induced OSM production from mast cells and macrophages but not from neutrophils, and OSM and IL-13 stimulation induced IL-6 production from nasal fibroblasts. CONCLUSION: In addition to type 2 inflammation, innate and IL-6-related cytokines are also elevated in the respiratory tract in AERD. Both OSM and IL-6 are locally produced in nasal polyps and likely promote pathology by negatively affecting epithelial barrier function. IL-4Rα blockade, although seemingly directed at type 2 inflammation, also decreases mediators of innate inflammation and epithelial dysregulation, which may contribute to dupilumab's therapeutic efficacy in AERD.

Feasibility Trial Exploring Immune-Related Biomarkers Pertaining to Rapid Immune Surveillance and Cytokine Changes after Consuming a Nutraceutical Supplement Containing Colostrum- and Egg-Based Low-Molecular-Weight Peptides.

Immune protection associated with consuming colostrum-based peptides is effective against bacterial and viral insults. The goal for this study was to document acute changes to immune surveillance and cytokine levels after consuming a single dose of a nutraceutical blend in the absence of an immune challenge. A double-blind, randomized, placebo-controlled, cross-over pilot study involved healthy participants attending two clinic visits. Blood draws were performed pre-consumption and at 1, 2, and 24 h after consuming a blend of bovine colostrum- and hen's egg-based low-molecular-weight peptides (CELMPs) versus a placebo. Immunophenotyping was performed by flow cytometry, and serum cytokines were measured by multiplex cytokine arrays. Consumption of CELMPs triggered increased immune surveillance after 1 h, involving monocytes (p < 0.1), natural killer (NK) cells (p < 0.1), and natural killer T (NKT) cells (p < 0.05). The number of NKT cells expressing the CD25 immunoregulatory marker increased at 1 and 2 h (p < 0.1). Increased serum levels of monocyte chemoattractant protein-1 (MCP-1) was observed at 2 and 24 h (24 h: p < 0.05). Selective reduction in pro-inflammatory cytokines was seen at 1, 2, and 24 h, where the 2-h reduction was highly significant for IL-6, IFN-γ, and IL-13. The rapid, transient increase in immune surveillance, in conjunction with the reduced levels of inflammatory markers, suggests that the CELMP blend of natural peptides provides immune benefits of use in preventive medicine. Further studies are warranted in chronic inflammatory conditions.

Global IL4Rα blockade exacerbates heart failure after an ischemic event in mice and humans.

Ischemic heart failure continues to be a highly prevalent disease among westernized countries and there is great interest in understanding the mechanisms preventing or exacerbating disease progression. The literature suggests an important role for the activation of interleukin-13 or interleukin-4 signaling in improving ischemic heart failure outcomes after myocardial infarction in mice. Dupilumab, a neutralizing antibody that inhibits the shared IL13/IL4 receptor subunit IL4Rα, is widely used for conditions such as ectopic dermatitis in humans. If global depletion of IL4Rα influences ischemic heart failure, either in mice or in humans taking dupilumab, is unknown. Here, we investigated the pathophysiological effects of global IL4Rα genetic deletion in adult mice after surgically induced myocardial infarction (MI). We also determined heart failure risk in patients with ischemic heart disease and concomitant usage of dupilumab using the collaborative patient data network TriNetX. Global deletion of IL4Rα results in exacerbated cardiac dysfunction associated with reduced capillary size after myocardial infarction in mice. In agreement with our findings in mice, dupilumab treatment significantly increased the risk of heart failure development in patients with preexisting diagnosis of ischemic heart disease. Our results indicate that systemic IL4Rα signaling is protective against heart failure development in adult mice and human patients specifically following an ischemic event. Thus, the compelling evidence presented hereby advocates for the development of a randomized clinical trial specifically investigating heart failure development after myocardial ischemia in patients taking dupilumab for another underlying condition.NEW & NOTEWORTHY A body of literature suggests a protective role for IL4Rα signaling postmyocardial infarction in mice. Here, our observational study demonstrates that humans taking the IL4Rα neutralizing antibody, dupilumab, have increased incidence of heart failure following an ischemic event. Similarly, global IL4Rα deletion in mice exacerbates heart failure postinfarct. To our knowledge, this is the first study reporting an adverse association in humans of dupilumab use with heart failure following a cardiac ischemic event.

Possibility of maintaining remission with topical therapy alone after withdrawal of dupilumab in Japanese patients with atopic dermatitis and their characteristics in the real world.

Psossibility and appropriate timing of discontinuation of dupilumab for atopic dermatitis (AD) remain unclear. We explored the possibility of patients, who could maintain remission with topical therapy alone after withdrawing dupilumab in the real world. Furthermore, we identified their characteristics. All adult AD patients who initiated dupilumab from June 2018 to July 2022 and were treated with dupilumab for more than 3 months at our hospital were included in this study. The observation period was from June 2018 to July 2023. In 138 patients, 58 (42.0%) discontinued dupilumab at least once. Among them, 18 (13.0%) discontinued dupilumab but reinitiated dupilumab later due to exacerbation. Only seven patients (5.1%) could maintain remission with topical therapy alone after discontinuation of dupilumab, with characteristics of lower POEM, VAS of pruritus, serum levels of TARC and LDH, and neutrophil counts at baseline, and those of longer duration of dupilumab until its discontinuation (24.0 ± 13.3 vs. 12.8 ± 7.3 months) and lower EASI and affected BSA at the discontinuation of dupilumab. In 118 patients treated with dupilumab for at least 1 year, 38 patients (32.2%) discontinued at least once. Only four patients (3.4%) could maintain remission with topical therapy alone after discontinuation of dupilumab, with characteristics of lower POEM at baseline and lower EASI at the discontinuation of dupilumab. In conclusion, maintaining remission after withdrawing dupilumab is challenging. Discontinuation of dupilumab may be considered in patients with low baseline POEM, after more than 2 years of dupilumab treatment, with a substantial decrease in EASI.

Revisiting the association of sudden infant death syndrome (SIDS) with polymorphisms of NHE3 and IL13.

OBJECTIVES: Disturbances of the central nervous system and immune system are thought to play a role in sudden infant death syndrome (SIDS). Dysregulated expression of sodium (Na+)/hydrogen (H+) exchanger 3 (NHE3) in the brainstem and of interleukin 13 (IL13) in the lungs has been observed in SIDS. An association of single-nucleotide polymorphisms (SNPs) in NHE3 and IL13 with SIDS has been proposed, but controversial results were reported. Therefore, there is a need to revisit the association of SNPs in NHE3 and IL13 with SIDS. METHODS: Genotyping of rs71597645 (G1131A) and rs2247114 (C2405T) in NHE3 and rs20541 (+ 4464A/G) in IL13 was performed in 201 SIDS cases and 338 controls. A meta-analysis was performed after merging our data with previously published data (all from European populations). RESULTS: Polymorphisms rs2247114 (NHE3) and rs20541 (IL13) were significantly associated with SIDS overall and in multiple subgroups, but no association was found for rs71597645 (NHE3). After combining our data with previously published data, a fixed-effect meta-analysis showed that rs2247114 in NHE3 retained a significant association with SIDS under a recessive model (OR 2.78, 95%CI 1.53 to 5.06; p = 0.0008). CONCLUSION: Our findings suggest an association of NHE3 variant rs2247114 (C2405T), though not rs71597645 (NHE3), with SIDS. A potential role of rs20541 (IL13) still has to be elucidated. Especially NHE3 seems to be an interesting topic for future SIDS research.

Dupilumab treatment improves signs, symptoms, quality of life, and work productivity in patients with atopic hand and foot dermatitis: Results from a phase 3, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Despite high disease burden, systemic treatment options for patients with atopic hand and/or foot dermatitis (H/F AD) are limited. OBJECTIVES: To evaluate efficacy and safety of dupilumab in H/F AD using specific instruments for assessing disease severity on hands and feet. METHODS: In this multicenter phase 3 trial, adults and adolescents with moderate-to-severe H/F AD were randomized to dupilumab monotherapy (regimen approved for generalized AD), or matched placebo. The primary endpoint was proportion of patients achieving Hand and Foot Investigator's Global Assessment score 0 or 1 at week 16. Secondary prespecified endpoints assessed the severity and extent of signs, symptom intensity (itch, pain), quality of life, and sleep. RESULTS: A total of 133 patients (adults = 106, adolescents = 27) were randomized to dupilumab (n = 67) or placebo (n = 66). At week 16, significantly more patients receiving dupilumab (n = 27) than placebo (n = 11) achieved Hand and Foot Investigator's Global Assessment score 0 or 1 (40.3% vs 16.7%; P = .003). All other prespecified endpoints were met. Safety was consistent with the known AD dupilumab profile. LIMITATIONS: Short-term, 16-week treatment period. CONCLUSION: Dupilumab monotherapy resulted in significant improvements across different domains of H/F AD with acceptable safety, supporting dupilumab as a systemic treatment approach for this often difficult to treat condition.

A call for clinical trials in glioblastoma multiforme for interleukin 4, interleukin 6, interleukin 13 and CD40.

Glioblastoma multiforme (GBM) is one of the most aggressive and deadly forms of brain cancer, which has a very complex tumor microenvironment (TME) promoting tumor growth, immune evasion, and resistance to therapy. The main players within this environment are represented by cytokines such as Interleukin-4, Interleukin-6, and Interleukin-13, along with the costimulatory molecule CD40. The paper draws back the curtain on the complex interactions played out by these molecules in contributing to the formation of a TME within GBM. IL-4 and IL-13 induce an immunosuppressive environment through the polarization of tumor-associated macrophages (TAMs) into a pro-tumoral M2 phenotype. In contrast, IL-6 takes part in the activation of the JAK-STAT3 pathway, enhancing survival and proliferation of tumor cells. In this context, CD40 either induces anti-tumor immunity through APC activation or facilitates tumors by angiogenesis and survival pathways. The synergistic actions of these molecules create feedback loops that keep up the malignancy of GBM and present a big problem for therapy. Knowledge of these interactions opens new ways for the development of multi-targeted therapeutic strategies at the other end. This may result in the interruption of the tumor-supportive environment in GBM, reducing tumor growth and improving patient outcomes by targeting IL-4, IL-6, IL-13, and CD40 simultaneously.

Diverse innate stimuli activate basophils through pathways involving Syk and IκB kinases.

Mature basophils play critical inflammatory roles during helminthic, autoimmune, and allergic diseases through their secretion of histamine and the type 2 cytokines interleukin 4 (IL-4) and IL-13. Basophils are activated typically by allergen-mediated IgE cross-linking but also by endogenous "innate" factors. The aim of this study was to identify the innate stimuli (cytokines, chemokines, growth factors, hormones, neuropeptides, metabolites, and bacterial products) and signaling pathways inducing primary basophil activation. Basophils from naïve mice or helminth-infected mice were cultured with up to 96 distinct stimuli and their influence on basophil survival, activation, degranulation, and IL-4 or IL-13 expression were investigated. Activated basophils show a heterogeneous phenotype and segregate into distinct subsets expressing IL-4, IL-13, activation, or degranulation markers. We find that several innate stimuli including epithelial derived inflammatory cytokines (IL-33, IL-18, TSLP, and GM-CSF), growth factors (IL-3, IL-7, TGFß, and VEGF), eicosanoids, metabolites, TLR ligands, and type I IFN exert significant direct effects on basophils. Basophil activation mediated by distinct upstream signaling pathways is always sensitive to Syk and IκB kinases-specific inhibitors but not necessarily to NFAT, STAT5, adenylate cyclase, or c-fos/AP-1 inhibitors. Thus, basophils are activated by very diverse mediators, but their activation seem controlled by a core checkpoint involving Syk and IκB kinases.

Type II Interleukin-4 Receptor Activation in Basal Breast Cancer Cells Promotes Tumor Progression via Metabolic and Epigenetic Modulation.

Interleukin-4 (IL4) is a Th2 cytokine that can signal through two different receptors, one of which-the type II receptor-is overexpressed by various cancer cells. Previously, we have shown that type II IL4 receptor signaling increases proliferation and metastasis in mouse models of breast cancer, as well as increasing glucose and glutamine metabolism. Here, we expand on those findings to determine mechanistically how IL4 signaling links glucose metabolism and histone acetylation to drive proliferation in the context of triple-negative breast cancer (TNBC). We used a combination of cellular, biochemical, and genomics approaches to interrogate TNBC cell lines, which represent a cancer type where high expression of the type II IL4 receptor is linked to reduced survival. Our results indicate that type II IL4 receptor activation leads to increased glucose uptake, Akt and ACLY activation, and histone acetylation in TNBC cell lines. Inhibition of glucose uptake through the deletion of Glut1 ablates IL4-induced proliferation. Additionally, pharmacological inhibition of histone acetyltransferase P300 attenuates IL4-mediated gene expression and proliferation in vitro. Our work elucidates a role for type II IL4 receptor signaling in promoting TNBC progression, and highlights type II IL4 signaling, as well as histone acetylation, as possible targets for therapy.

Targeting Interleukin-13 Receptor α2 and EphA2 in Aggressive Breast Cancer Subtypes with Special References to Chimeric Antigen Receptor T-Cell Therapy.

Breast cancer (BCA) remains the leading cause of cancer-related mortality among women worldwide. This review delves into the therapeutic challenges of BCA, emphasizing the roles of interleukin-13 receptor α2 (IL-13Rα2) and erythropoietin-producing hepatocellular receptor A2 (EphA2) in tumor progression and resistance. Highlighting their overexpression in BCA, particularly in aggressive subtypes, such as Her-2-enriched and triple-negative breast cancer (TNBC), we discuss the potential of these receptors as targets for chimeric antigen receptor T-cell (CAR-T) therapies. We examine the structural and functional roles of IL-13Rα2 and EphA2, their pathological significance in BCA, and the promising therapeutic avenues their targeting presents. With an in-depth analysis of current immunotherapeutic strategies, including the limitations of existing treatments and the potential of dual antigen-targeting CAR T-cell therapies, this review aims to summarize potential future novel, more effective therapeutic interventions for BCA. Through a thorough examination of preclinical and clinical studies, it underlines the urgent need for targeted therapies in combating the high mortality rates associated with Her-2-enriched and TNBC subtypes and discusses the potential role of IL-13Rα2 and EphA2 as promising candidates for the development of CAR T-cell therapies.

Interleukin Profiling in Atopic Dermatitis and Chronic Nodular Prurigo.

The clinical manifestations of atopic dermatitis (AD) and chronic nodular prurigo (CNPG) include pruritus and eczema/lesions, posing significant challenges for patients. Th2 cells and ILC2, marked by cytokine production-particularly IL-4/13-are crucial therapeutic targets. Despite displaying a dose-dependent lack of pruritus induction post-injection, IL-13 acts through the IL-13Rα1 and IL-13Rα2 receptor system. Our study focused on investigating ex vivo skin biopsies in AD (n = 17), CNPG (n = 14) and healthy controls (HC; n = 10), examining the gene expression landscape of interleukins linked with pruritus (IL-13, IL-4, IL-31) and their corresponding receptors. Compared to HC, results revealed a significant upregulation of IL-4, IL-13, and IL-13RA1 in AD, whereas CNPG did not show increased IL13 expression. Notably, the decoy receptor IL-13RA2 displayed intriguing patterns, with AD showing a marked increase compared to both HC and CNPG. Positive correlations between receptor expression and itch intensity and hyperkinesis sensation underscore clinical relevance, potentially serving as biomarkers. The findings suggest a pivotal role of IL-4 and IL-13, along with IL-13RA1, in pruritus pathogenesis in both entities, while IL-13 upregulation in AD is countered by IL-13RA2. The comparable expression of IL-13RA2 to HC in CNPG suggests the absence of this regulatory mechanism, potentially worsening the disease and leading to prolonged scratching behavior. These insights illuminate the intricate interplay of interleukins and receptors in different pruritus phenotypes, laying the groundwork for understanding underlying mechanisms and offering avenues for therapeutic intervention.

Interleukin-13 Treatment of Living Lung Tissue Model Alters the Metabolome and Proteome-A Nano-DESI MS Metabolomics and Shotgun Proteomics Study.

Asthma is a chronic respiratory disease with one of the largest numbers of cases in the world; thus, constant investigation and technical development are needed to unravel the underlying biochemical mechanisms. In this study, we aimed to develop a nano-DESI MS method for the in vivo characterization of the cellular metabolome. Using air-liquid interface (ALI) cell layers, we studied the role of Interleukin-13 (IL-13) on differentiated lung epithelial cells acting as a lung tissue model. We demonstrate the feasibility of nano-DESI MS for the in vivo monitoring of basal-apical molecular transport, and the subsequent endogenous metabolic response, for the first time. Conserving the integrity of the ALI lung-cell layer enabled us to perform temporally resolved metabolomic characterization followed by "bottom-up" proteomics on the same population of cells. Metabolic remodeling was observed upon histamine and corticosteroid treatment of the IL-13-exposed lung cell monolayers, in correlation with alterations in the proteomic profile. This proof of principle study demonstrates the utility of in vivo nano-DESI MS for characterizing ALI tissue layers, and the new markers identified in our study provide a good starting point for future, larger-scale studies.

Microbiota Alterations in Lung, Ileum, and Colon of Guinea Pigs with Cough Variant Asthma.

Alterations in the microbiota composition, or ecological dysbiosis, have been implicated in the development of various diseases, including allergic diseases and asthma. Examining the relationship between microbiota alterations in the host and cough variant asthma (CVA) may facilitate the discovery of novel therapeutic strategies. To elucidate the diversity and difference of microbiota across three ecological niches, we performed 16S rDNA amplicon sequencing on lung, ileum, and colon samples. We assessed the levels of interleukin-12 (IL-12) and interleukin-13 (IL-13) in guinea pig bronchoalveolar lavage fluid using the enzyme-linked immunosorbent assay (ELISA). We applied Spearman's analytical method to evaluate the correlation between microbiota and cytokines. The results demonstrated that the relative abundance, α-diversity, and ß-diversity of the microbial composition of the lung, ileum, and colon varied considerably. The ELISA results indicated a substantial increase in the level of IL-13 and a decreasing trend in the level of IL-12 in the CVA guinea pigs. The Spearman analysis identified a correlation between Mycoplasma, Faecalibaculum, and Ruminococcus and the inflammatory factors in the CVA guinea pigs. Our guinea pig model showed that core microorganisms, such as Mycoplasma in the lung, Faecalibaculum in the ileum, and Ruminococcus in the colon, may play a crucial role in the pathogenesis of CVA. The most conspicuous changes in the ecological niche were observed in the guinea pig ileum, followed by the lung, while relatively minor changes were observed in the colon. Notably, the microbial structure of the ileum niche approximated that of the colon niche. Therefore, the results of this study suggest that CVA development is closely related to the dysregulation of ileal, lung, and colon microbiota and the ensuing inflammatory changes in the lung.

Restoration of Skin Barrier Abnormalities with IL4/13 Inhibitors and Jak Inhibitors in Atopic Dermatitis: A Systematic Review.

Background and Objectives: Atopic dermatitis is a chronic inflammatory skin disorder with a significant burden on patients' quality of life. This systematic review aims to evaluate the restoration of skin barrier abnormalities with interleukin-4/interleukin-13 (IL-4/IL-13) inhibitors and Janus kinase (JAK) inhibitors in atopic dermatitis. Materials and Methods: A comprehensive review of the literature was conducted, focusing on studies that assess the use of IL-4/IL-13 inhibitors and JAK inhibitors for atopic dermatitis. We identified eligible studies by searching Medline via PubMed with a special focus on their effect on the restoration of the epidermal barrier. Included studies evaluated the transepidermal water loss (TEWL), the reduction in epidermal thickness (ET), the improvement in ceramide synthesis, and the increase in stratum corneum hydration (SCH) with IL-4/IL-13 inhibitors and JAK inhibitors. The quality of included studies was assessed using the ROBINS-I and the RoB 2.0 tool for assessing the risk of bias. Results: Ten of the included studies concern dupilumab, while two concern JAK inhibitors. Ten were observational studies and two were randomized controlled trials (RCTs). The total number of included participants was 378 concerning dupilumab and 38 concerning JAK inhibitors. Five studies did not include any comparison group, three included healthy volunteers, two were conducted versus placebo, and two compared dupilumab with other treatments. The follow-up period ranged between 29 days and 32 weeks. The results demonstrated a significant decrease in transepidermal water loss (TEWL) and an increase in SCH on eczematous lesions for patients with sustained response to dupilumab treatment and observed improvements in ET and filaggrin (FLG) staining, which further support the efficacy of JAK inhibitors in enhancing skin barrier function. Conclusions: This review underscores the efficacy of IL-4/IL-13 inhibitors in improving skin barrier function. However, the limited number of studies focusing on JAK inhibitors and the overall lack of RCTs highlight the need for further research to establish the definitive role of IL-4/IL-13 inhibitors and JAK inhibitors in the restoration of the skin barrier.

Development of a potent high-affinity human therapeutic antibody via novel application of recombination signal sequence-based affinity maturation.

Therapeutic antibody development requires discovery of an antibody molecule with desired specificities and drug-like properties. For toxicological studies, a therapeutic antibody must bind the ortholog antigen with a similar affinity to the human target to enable relevant dosing regimens, and antibodies falling short of this affinity design goal may not progress as therapeutic leads. Herein, we report the novel use of mammalian recombination signal sequence (RSS)-directed recombination for complementarity-determining region-targeted protein engineering combined with mammalian display to close the species affinity gap of human interleukin (IL)-13 antibody 731. This fully human antibody has not progressed as a therapeutic in part because of a 400-fold species affinity gap. Using this nonhypothesis-driven affinity maturation method, we generated multiple antibody variants with improved IL-13 affinity, including the highest affinity antibody reported to date (34 fM). Resolution of a cocrystal structure of the optimized antibody with the cynomolgus monkey (or nonhuman primate) IL-13 protein revealed that the RSS-derived mutations introduced multiple successive amino-acid substitutions resulting in a de novo formation of a π-π stacking-based protein-protein interaction between the affinity-matured antibody heavy chain and helix C on IL-13, as well as an introduction of an interface-distant residue, which enhanced the light chain-binding affinity to target. These mutations synergized binding of heavy and light chains to the target protein, resulting in a remarkably tight interaction, and providing a proof of concept for a new method of protein engineering, based on synergizing a mammalian display platform with novel RSS-mediated library generation.