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Immunity Apr 2024Damage-associated molecular patterns (DAMPs) are endogenous danger molecules produced in cellular damage or stress, and they can activate the innate immune system. DAMPs... (Review)
Review
Damage-associated molecular patterns (DAMPs) are endogenous danger molecules produced in cellular damage or stress, and they can activate the innate immune system. DAMPs contain multiple types of molecules, including nucleic acids, proteins, ions, glycans, and metabolites. Although these endogenous molecules do not trigger immune response under steady-state condition, they may undergo changes in distribution, physical or chemical property, or concentration upon cellular damage or stress, and then they become DAMPs that can be sensed by innate immune receptors to induce inflammatory response. Thus, DAMPs play an important role in inflammation and inflammatory diseases. In this review, we summarize the conversion of homeostatic molecules into DAMPs; the diverse nature and classification, cellular origin, and sensing of DAMPs; and their role in inflammation and related diseases. Furthermore, we discuss the clinical strategies to treat DAMP-associated diseases via targeting DAMP-sensing receptors.
Topics: Humans; Inflammation; Immunity, Innate; Receptors, Immunologic; Nucleic Acids; Alarmins
PubMed: 38599169
DOI: 10.1016/j.immuni.2024.03.002 -
American Journal of Respiratory and... Apr 2024In asthma, sputum group 2 innate lymphoid cells (ILC2) are activated within 7h after allergen challenge. Neuroimmune interactions mediate rapid host responses at mucosal...
RATIONALE
In asthma, sputum group 2 innate lymphoid cells (ILC2) are activated within 7h after allergen challenge. Neuroimmune interactions mediate rapid host responses at mucosal interfaces. In murine models of asthma, lung ILC2 co-localize to sensory neuronal termini expressing the neuropeptide, neuromedin U (NMU) and NMU stimulates type 2 cytokines secretion by ILC2 with additive effects to alarmins, .
OBJECTIVES
Investigate effect of NMU/NMUR1 axis on early activation of ILC2 in asthma.
METHODS
M ild asthmatics (n=8) were enrolled in a diluent-controlled, allergen-inhalation challenge study. Sputum ILC2 expression of NMU receptor 1 (NMUR1) and T2 cytokines were enumerated by flow cytometry and airway NMU levels were assessed by ELISA. This was compared to samples from moderate-severe asthmatics (n=9). Flow sort-purified and expanded ILC2 were used for functional assays and transcriptomic analyses.
RESULTS
Significant increases in sputum ILC2 expressing NMUR1 were detected 7h post- allergen versus diluent challenge where the majority of NMUR1ILC2 expressed IL-5/IL-13. Sputum NMUR+ILC2 were significantly greater in mild versus moderate-severe asthmatics and NMUR1ILC2 correlated inversely with the dose of inhaled corticosteroid in the latter group. Co-culturing with alarmins upregulated in ILC2, which was attenuated by dexamethasone. NMU stimulated T2 cytokine expression by ILC2, maximal at 6h was abrogated by dexamethasone or specific signaling inhibitors for mitogen-activated protein kinase ½, phospho-inositol 3 kinase but not IL-33 signaling moiety MyD88, .
CONCLUSIONS
The NMU/NMUR1 axis stimulates rapid effects on ILC2, and maybe an important early activator of these cells in eosinophilic inflammatory responses in asthma.
PubMed: 38598774
DOI: 10.1164/rccm.202311-2164OC -
The Journal of Experimental Medicine Jun 2024Environmental airborne antigens are central to the development of allergic asthma, but the cellular processes that trigger disease remain incompletely understood. In...
Environmental airborne antigens are central to the development of allergic asthma, but the cellular processes that trigger disease remain incompletely understood. In this report, Schmitt et al. (https://doi.org/10.1084/jem.20231236) identify TNF-like protein 1A (TL1A) as an epithelial alarmin constitutively expressed by a subset of lung epithelial cells, which is released in response to airborne microbial challenge and synergizes with IL-33 to drive allergic disease.
Topics: Humans; Asthma; Alarmins; Epithelial Cells; Hypersensitivity; Lung
PubMed: 38597953
DOI: 10.1084/jem.20240389 -
The Journal of Experimental Medicine Jun 2024Epithelium-derived cytokines or alarmins, such as interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP), are major players in type 2 immunity and asthma. Here,...
Epithelium-derived cytokines or alarmins, such as interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP), are major players in type 2 immunity and asthma. Here, we demonstrate that TNF-like ligand 1A (TL1A) is an epithelial alarmin, constitutively expressed in alveolar epithelium at steady state in both mice and humans, which cooperates with IL-33 for early induction of IL-9high ILC2s during the initiation of allergic airway inflammation. Upon synergistic activation by IL-33 and TL1A, lung ILC2s acquire a transient IL-9highGATA3low "ILC9" phenotype and produce prodigious amounts of IL-9. A combination of large-scale proteomic analyses, lung intravital microscopy, and adoptive transfer of ILC9 cells revealed that high IL-9 expression distinguishes a multicytokine-producing state-of-activated ILC2s with an increased capacity to initiate IL-5-dependent allergic airway inflammation. Similar to IL-33 and TSLP, TL1A is expressed in airway basal cells in healthy and asthmatic human lungs. Together, these results indicate that TL1A is an epithelium-derived cytokine and an important cofactor of IL-33 in the airways.
Topics: Animals; Humans; Mice; Alarmins; Asthma; Cytokines; Immunity, Innate; Inflammation; Interleukin-33; Interleukin-9; Lymphocytes; Proteomics
PubMed: 38597952
DOI: 10.1084/jem.20231236 -
Frontiers in Medicine 2024The pathogenesis of atopic dermatitis (AD) is understood to be crucially influenced by three main factors: dysregulation of the immune response, barrier dysfunction, and... (Review)
Review
The pathogenesis of atopic dermatitis (AD) is understood to be crucially influenced by three main factors: dysregulation of the immune response, barrier dysfunction, and pruritus. In the lesional skin of AD, various innate immune cells, including Th2 cells, type 2 innate lymphoid cells (ILC2s), and basophils, produce Th2 cytokines [interleukin (IL)-4, IL-5, IL-13, IL-31]. Alarmins such as TSLP, IL-25, and IL-33 are also produced by epidermal keratinocytes, amplifying type 2 inflammation. In the chronic phase, not only Th2 cells but also Th22 and Th17 cells increase in number, leading to suppression of filaggrin expression by IL-4, IL-13, and IL-22, which further deteriorates the epidermal barrier function. Dupilumab, which targets IL-4 and IL-13, has shown efficacy in treating moderate to severe AD. Nemolizumab, targeting IL-31RA, effectively reduces pruritus in AD patients. In addition, clinical trials with fezakinumab, targeting IL-22, have demonstrated promising results, particularly in severe AD cases. Conversely, in murine models of AD, several cytokines, initially regarded as promising therapeutic targets, have not demonstrated sufficient efficacy in clinical trials. IL-33 has been identified as a potent activator of immune cells, exacerbating AD in murine models and correlating with disease severity in human patients. However, treatments targeting IL-33 have not shown sufficient efficacy in clinical trials. Similarly, thymic stromal lymphopoietin (TSLP), integral to type 2 immune responses, induces dermatitis in animal models and is elevated in human AD, yet clinical treatments like tezepelumab exhibit limited efficacy. Therapies targeting IL-1α, IL-5, and IL-17 also failed to achieve sufficient efficacy in clinical trials. It has become clear that for treating AD, IL-4, IL-13, and IL-31 are relevant therapeutic targets during the acute phase, while IL-22 emerges as a target in more severe cases. This delineation underscores the necessity of considering distinct pathophysiological aspects and therapeutic targets in AD between mouse models and humans. Consequently, this review delineates the distinct roles of cytokines in the pathogenesis of AD, juxtaposing their significance in human AD from clinical trials against insights gleaned from AD mouse models. This approach will improve our understanding of interspecies variation and facilitate a deeper insight into the pathogenesis of AD in humans.
PubMed: 38590314
DOI: 10.3389/fmed.2024.1342176 -
BioRxiv : the Preprint Server For... Mar 2024Neurons have the unique capacity to adapt output in response to changes in their environment. Within seconds, sensory nerve endings can become hypersensitive to stimuli...
Neurons have the unique capacity to adapt output in response to changes in their environment. Within seconds, sensory nerve endings can become hypersensitive to stimuli in response to potentially damaging events. The underlying behavioral response is well studied, but several of the key signaling molecules that mediate sensory hypersensitivity remain unknown. We previously discovered that peripheral voltage-gated Ca2.2 channels in nerve endings in skin are essential for the rapid, transient increase in sensitivity to heat, but not to mechanical stimuli, that accompanies intradermal capsaicin. Here we report that the cytokine interleukin-1α (IL-1α), an alarmin, is necessary and sufficient to trigger rapid heat and mechanical hypersensitivity in skin. Of 20 cytokines screened, only IL-1α was consistently detected in hind paw interstitial fluid in response to intradermal capsaicin and, similar to behavioral sensitivity to heat, IL-1α levels were also dependent on peripheral Ca2.2 channel activity. Neutralizing IL-1α in skin significantly reduced capsaicin-induced changes in hind paw sensitivity to radiant heat and mechanical stimulation. Intradermal IL-1α enhances behavioral responses to stimuli and, in culture, IL-1α enhances the responsiveness of -expressing sensory neurons. Together, our data suggest that IL-1α is the key cytokine that underlies rapid and reversible neuroinflammatory responses in skin.
PubMed: 38585803
DOI: 10.1101/2023.12.17.572072 -
Frontiers in Immunology 2024The alarmin IL-33 has been implicated in the pathology of immune-mediated liver diseases. IL-33 activates regulatory T cells (Tregs) and type 2 innate lymphoid cells...
INTRODUCTION
The alarmin IL-33 has been implicated in the pathology of immune-mediated liver diseases. IL-33 activates regulatory T cells (Tregs) and type 2 innate lymphoid cells (ILC2s) expressing the IL-33 receptor ST2. We have previously shown that endogenous IL-33/ST2 signaling activates ILC2s that aggravate liver injury in murine immune-mediated hepatitis. However, treatment of mice with exogenous IL-33 before induction of hepatitis ameliorated disease severity. Since IL-33 induces expression of amphiregulin (AREG) crucial for Treg function, we investigated the immunoregulatory role of the ST2 Treg/AREG axis in immune-mediated hepatitis.
METHODS
C57BL/6, ST2-deficient (Il1rl1) and Areg mice received concanavalin A to induce immune-mediated hepatitis. Foxp3Cre x ST2fl/fl mice were pre-treated with IL-33 before induction of immune-mediated hepatitis. Treg function was assessed by adoptive transfer experiments and suppression assays. The effects of AREG and IL-33 on ST2 Tregs and ILC2s were investigated . Immune cell phenotype was analyzed by flow cytometry.
RESULTS AND DISCUSSION
We identified IL-33-responsive ST2 Tregs as an effector Treg subset in the murine liver, which was highly activated in immune-mediated hepatitis. Lack of endogenous IL-33 signaling in Il1rl1 mice aggravated disease pathology. This was associated with reduced Treg activation. Adoptive transfer of exogenous IL-33-activated ST2 Tregs before induction of hepatitis suppressed inflammatory T-cell responses and ameliorated disease pathology. We further showed increased expression of AREG by hepatic ST2 Tregs and ILC2s in immune-mediated hepatitis. Areg mice developed more severe liver injury, which was associated with enhanced ILC2 activation and less ST2 Tregs in the inflamed liver. Exogenous AREG suppressed ILC2 cytokine expression and enhanced ST2 Treg activation . In addition, Tregs from Areg mice were impaired in their capacity to suppress CD4 T-cell activation . Moreover, application of exogenous IL-33 before disease induction did not protect Foxp3Cre x ST2fl/fl mice lacking ST2 Tregs from immune-mediated hepatitis. In summary, we describe an immunoregulatory role of the ST2 Treg/AREG axis in immune-mediated hepatitis, in which AREG suppresses the activation of hepatic ILC2s while maintaining ST2 Tregs and reinforcing their immunosuppressive capacity in liver inflammation.
Topics: Animals; Mice; Amphiregulin; Hepatitis; Immunity, Innate; Interleukin-1 Receptor-Like 1 Protein; Interleukin-33; Lymphocytes; Mice, Inbred C57BL; T-Lymphocytes, Regulatory
PubMed: 38571949
DOI: 10.3389/fimmu.2024.1351405 -
Current Opinion in Allergy and Clinical... Jun 2024This review aims to explore role of emerging biologics, including ligelizumab, UB-221, dupilumab, and antialarmins, in food allergy management. With a focus on recent... (Review)
Review
PURPOSE OF REVIEW
This review aims to explore role of emerging biologics, including ligelizumab, UB-221, dupilumab, and antialarmins, in food allergy management. With a focus on recent developments, we evaluate their promise in mitigating adverse events during oral immunotherapy (OIT), reducing allergic reactions, and addressing the limitations of current therapeutic options.
RECENT FINDINGS
Antiimmunoglobulin E mAbs, exemplified by omalizumab, demonstrate efficacy in desensitization and safety improvement during multiallergen OIT. Next-generation antibodies like ligelizumab and UB-221 exhibit enhanced potency and unique mechanisms, holding promise for food allergy treatment. Dupilumab, targeting IL-4 receptor alpha, presents potential benefits in decreasing allergen-specific IgE and modifying the atopic march. Exploration of antialarmins, specifically anti-IL-33 (etokimab) and anti-TSLP (tezepelumab), reveals encouraging results, with etokimab showing early success in peanut allergy trials.
SUMMARY
Biologics hold promising potential for food allergy treatment. Tailoring therapeutic approaches based on shared decision-making becomes pivotal. While omalizumab remains a significant option, next-generation anti-IgE antibodies and agents targeting alarmins exhibit unique strengths. Dupilumab, despite limited success as monotherapy, shows promise as an adjunct for OIT. Careful consideration of treatment goals, patient preferences, and the evolving landscape of biologics will shape future clinical practice, offering allergists an expanded toolbox for personalized food allergy management.
Topics: Humans; Food Hypersensitivity; Biological Products; Desensitization, Immunologic; Animals; Anti-Allergic Agents; Immunoglobulin E; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal; Allergens; Omalizumab
PubMed: 38547423
DOI: 10.1097/ACI.0000000000000981 -
Frontiers in Immunology 2024LTX-315 is a synthetic cationic oncolytic peptide with potent anticancer activity but limited toxicity for non-malignant cells. LTX-315 induces both immunogenic tumor...
LTX-315 is a synthetic cationic oncolytic peptide with potent anticancer activity but limited toxicity for non-malignant cells. LTX-315 induces both immunogenic tumor cell death and generation of tumor-specific immune responses in multiple experimental tumor models. Given the central role of dendritic cell (DC) maturation in the induction of antigen-specific immunity, we investigated the effect of LTX-315 treatment on the maturation of tumor-infiltrating DCs (TiDCs) and the generation of anti-melanoma immunity. We found that LTX-315 treatment induces the maturation of DCs, both indirectly through the release of cancer cell-derived damage-associated molecular patterns (DAMPs)/alarmins and nucleic acids (DNA and RNA) capable of triggering distinct Toll-like receptor (TLR) signaling, and, directly by activating TLR7. The latter results in the ignition of multiple intracellular signaling pathways that promotes DC maturation, including NF-κB, mitogen activated protein kinases (MAPKs), and inflammasome signaling, as well as increased type 1 interferon production. Critically, the effects of LTX-315 on DCs the consequent promotion of anti-melanoma immunity depend on the cytosolic signal transducer myeloid differentiation response gene 88 (MyD88). These results cast light on the mechanisms by which LTX-315 induces DC maturation and hence elicits anticancer immunity, with important implications for the use of LTX-315 as an anticancer immunotherapeutic.
Topics: Adaptor Proteins, Signal Transducing; Dendritic Cells; Myeloid Differentiation Factor 88; Oligopeptides; Toll-Like Receptors
PubMed: 38545099
DOI: 10.3389/fimmu.2024.1332922 -
Revista Alergia Mexico (Tecamachalco,... Dec 2023Despite promising advancements in oral immunotherapy for food allergies, medical implementation faces limitations. Non-specific treatment options based on inhibiting the...
Despite promising advancements in oral immunotherapy for food allergies, medical implementation faces limitations. Non-specific treatment options based on inhibiting the type 2 inflammatory pathway, including monoclonal antibodies, are under investigation. TNX-901 and omalizumab have demonstrated increased reaction thresholds, reducing adverse events in peanut-allergic patients. Dupilumab, blocking the IL-4 receptor, shows positive results in both food allergies and eosinophilic esophagitis. Antibodies against alarmins and anti-IL-5, such as etokimab and mepolizumab, have proven efficacy in preclinical studies and clinical trials. While further studies are needed to establish their practical clinical use and determine suitability for different types of food allergies, these monoclonal antibodies present a promising horizon for the treatment of such conditions.
Topics: Humans; Biological Products; Antibodies, Monoclonal; Food Hypersensitivity; Immunotherapy; Omalizumab
PubMed: 38506875
DOI: 10.29262/ram.v70i4.1340