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Frontiers in Immunology 2021Immunogenic cell death (ICD) is a form of regulated cell death (RCD) induced by various stresses and produces antitumor immunity damage-associated molecular patterns... (Review)
Review
Immunogenic cell death (ICD) is a form of regulated cell death (RCD) induced by various stresses and produces antitumor immunity damage-associated molecular patterns (DAMPs) release or exposure, mainly including high mobility group box 1 (HMGB1), calreticulin (CRT), adenosine triphosphate (ATP), and heat shock proteins (HSPs). Emerging evidence has suggested that ionizing radiation (IR) can induce ICD, and the dose, type, and fractionation of irradiation influence the induction of ICD. At present, IR-induced ICD is mainly verified in mice and there is few clinical evidence about it. To boost the induction of ICD by IR, some strategies have shown synergy with IR to enhance antitumor immune response, such as hyperthermia, nanoparticles, and chemotherapy. In this review, we focus on the molecular mechanisms of ICD, ICD-promoting factors associated with irradiation, the clinical evidence of ICD, and immunogenic forms of cell death. Finally, we summarize various methods of improving ICD induced by IR.
Topics: Alarmins; Animals; Antigens, Neoplasm; Biomarkers; Combined Modality Therapy; Cytokines; Dose-Response Relationship, Radiation; Ferroptosis; HMGB1 Protein; Humans; Hyperthermia, Induced; Immunogenic Cell Death; Mice; Morpholines; Necroptosis; Neoplasms; Piperazines; Pyrroles; Radiation Tolerance; Radiation, Ionizing
PubMed: 34489957
DOI: 10.3389/fimmu.2021.705361 -
Cell Death and Differentiation Jan 2019Pyroptosis and necroptosis represent two pathways of genetically encoded necrotic cell death. Although these cell death programmes can protect the host against microbial... (Review)
Review
Pyroptosis and necroptosis represent two pathways of genetically encoded necrotic cell death. Although these cell death programmes can protect the host against microbial pathogens, their dysregulation has been implicated in a variety of autoimmune and auto-inflammatory conditions. The disease-promoting potential of necroptosis and pyroptosis is likely a consequence of their ability to induce a lytic cell death. This cell suicide mechanism, distinct from apoptosis, allows the release of immunogenic cellular content, including damage-associated molecular patterns (DAMPs), and inflammatory cytokines such as interleukin-1β (IL-1β), to trigger inflammation. In this Review, we discuss recent discoveries that have advanced our understanding on the primary functions of pyroptosis and necroptosis, including evidence for the specific cytokines and DAMPs responsible for driving inflammation. We compare the similar and unique aspects of pyroptotic- and necroptotic-induced membrane damage, and explore how these may functionally impact distinct intracellular organelles and signalling pathways. We also examine studies highlighting the crosstalk that can occur between necroptosis and pyroptosis signalling, and evidence supporting the physiological significance of this convergence. Ultimately, a better understanding of the similarities, unique aspects and crosstalk of pyroptosis and necroptosis will inform as to how these cell death pathways might be manipulated for therapeutic benefit.
Topics: Alarmins; Animals; Caspase 1; Cytokines; HMGB1 Protein; Humans; Inflammasomes; Inflammation; Intracellular Signaling Peptides and Proteins; Necroptosis; Necrosis; Phosphate-Binding Proteins; Protein Kinases; Pyroptosis; Signal Transduction
PubMed: 30341423
DOI: 10.1038/s41418-018-0212-6 -
Journal of Cellular Physiology May 2021High-mobility group box 1 (HMGB1) was initially recognized as a ubiquitous nuclear protein involved in maintaining the nucleosome integrity and facilitating gene... (Review)
Review
High-mobility group box 1 (HMGB1) was initially recognized as a ubiquitous nuclear protein involved in maintaining the nucleosome integrity and facilitating gene transcription. HMGB1 has since been reevaluated to be a prototypical damage-associated molecular pattern (DAMP) protein, and together with its exogenous counterpart, pathogen-associated molecular pattern (PAMP), completes the body's alarmin system against disturbances in homeostasis. HMGB1 can be released into the extracellular matrix (ECM) by either granulocytes or necrotic cells to serve as a chemotaxis/cytokine during infection, endotoxemia, hypoxia, ischemia-reperfusion events, and cancer. Different isoforms of HMGB1 present with distinctive physiological functions in ECM-fully-reduced HMGB1 (all thiol) acts as the initial damage signal to recruit circulating myeloid cells, disulfide HMGB1 behaves as a cytokine to activate macrophages and neutrophils, and both signals are turned off when HMGB1 is terminally oxidized into the final sulfonate form. Targeting HMGB1 constitutes a favorable therapeutic strategy for inflammation and inflammatory diseases. Antagonists such as ethyl pyruvate inhibit HMGB1 by interfering with its cytoplasmic exportation, while others such as glycyrrhizin directly bind to HMGB1 and render it unavailable for its receptors. The fact that a mixture of different HMGB1 isoforms is present in the ECM poses a challenge in pinpointing the exact role of an individual antagonist. A more discriminative probe for HMGB1 may be necessary to advance our knowledge of HMGB1, HMGB1 antagonists, and inflammatory-related diseases.
Topics: Alarmins; Animals; Cytokines; Endotoxemia; HMGB1 Protein; Humans; Inflammation; Macrophages
PubMed: 33107103
DOI: 10.1002/jcp.30125 -
Cells Aug 2019Located at the skin surface, keratinocytes (KCs) are constantly exposed to external stimuli and are the first responders to invading pathogens and injury. Upon skin... (Review)
Review
Located at the skin surface, keratinocytes (KCs) are constantly exposed to external stimuli and are the first responders to invading pathogens and injury. Upon skin injury, activated KCs secrete an array of alarmin molecules, providing a rapid and specific innate immune response against danger signals. However, dysregulation of the innate immune response of KCs may lead to uncontrolled inflammation and psoriasis pathogenesis. Keratins (KRT) are the major structural intermediate filament proteins in KCs and are expressed in a highly specific pattern at different differentiation stages of KCs. While KRT14-KRT5 is restricted to basal proliferative KCs, and KRT10-KRT1 is restricted to suprabasal differentiated KCs in normal skin epidermis, the wound proximal KCs downregulate KRT10-K1 and upregulate KRT16/KRT17-KRT6 upon skin injury. Recent studies have recognized KRT6/16/17 as key early barrier alarmins and upregulation of these keratins alters proliferation, cell adhesion, migration and inflammatory features of KCs, contributing to hyperproliferation and innate immune activation of KCs in response to an epidermal barrier breach, followed by the autoimmune activation of T cells that drives psoriasis. Here, we have reviewed how keratins are dysregulated during skin injury, their roles in wound repairs and in initiating the innate immune system and the subsequent autoimmune amplification that arises in psoriasis.
Topics: Alarmins; Cell Adhesion; Cell Differentiation; Cell Movement; Cell Proliferation; Gene Expression Regulation; Humans; Immunity, Innate; Keratin-16; Keratin-17; Keratin-6; Psoriasis; Wound Healing
PubMed: 31374826
DOI: 10.3390/cells8080807 -
Acta Biomaterialia Apr 2017The immune system plays a central role in tissue repair and regeneration. Indeed, the immune response to tissue injury is crucial in determining the speed and the... (Review)
Review
UNLABELLED
The immune system plays a central role in tissue repair and regeneration. Indeed, the immune response to tissue injury is crucial in determining the speed and the outcome of the healing process, including the extent of scarring and the restoration of organ function. Therefore, controlling immune components via biomaterials and drug delivery systems is becoming an attractive approach in regenerative medicine, since therapies based on stem cells and growth factors have not yet proven to be broadly effective in the clinic. To integrate the immune system into regenerative strategies, one of the first challenges is to understand the precise functions of the different immune components during the tissue healing process. While remarkable progress has been made, the immune mechanisms involved are still elusive, and there is indication for both negative and positive roles depending on the tissue type or organ and life stage. It is well recognized that the innate immune response comprising danger signals, neutrophils and macrophages modulates tissue healing. In addition, it is becoming evident that the adaptive immune response, in particular T cell subset activities, plays a critical role. In this review, we first present an overview of the basic immune mechanisms involved in tissue repair and regeneration. Then, we highlight various approaches based on biomaterials and drug delivery systems that aim at modulating these mechanisms to limit fibrosis and promote regeneration. We propose that the next generation of regenerative therapies may evolve from typical biomaterial-, stem cell-, or growth factor-centric approaches to an immune-centric approach.
STATEMENT OF SIGNIFICANCE
Most regenerative strategies have not yet proven to be safe or reasonably efficient in the clinic. In addition to stem cells and growth factors, the immune system plays a crucial role in the tissue healing process. Here, we propose that controlling the immune-mediated mechanisms of tissue repair and regeneration may support existing regenerative strategies or could be an alternative to using stem cells and growth factors. The first part of this review we highlight key immune mechanisms involved in the tissue healing process and marks them as potential target for designing regenerative strategies. In the second part, we discuss various approaches using biomaterials and drug delivery systems that aim at modulating the components of the immune system to promote tissue regeneration.
Topics: Alarmins; Animals; Biocompatible Materials; Dendritic Cells; Drug Delivery Systems; Humans; Immunity, Innate; Inflammation Mediators; Leukocytes; Mast Cells; Myeloid Cells; Pericytes; Regeneration; Regenerative Medicine; Wound Healing; Wounds and Injuries
PubMed: 28119112
DOI: 10.1016/j.actbio.2017.01.056 -
Cell Stem Cell Apr 2021Functional contributions of individual cellular components of the bone-marrow microenvironment to myelofibrosis (MF) in patients with myeloproliferative neoplasms (MPNs)...
Functional contributions of individual cellular components of the bone-marrow microenvironment to myelofibrosis (MF) in patients with myeloproliferative neoplasms (MPNs) are incompletely understood. We aimed to generate a comprehensive map of the stroma in MPNs/MFs on a single-cell level in murine models and patient samples. Our analysis revealed two distinct mesenchymal stromal cell (MSC) subsets as pro-fibrotic cells. MSCs were functionally reprogrammed in a stage-dependent manner with loss of their progenitor status and initiation of differentiation in the pre-fibrotic and acquisition of a pro-fibrotic and inflammatory phenotype in the fibrotic stage. The expression of the alarmin complex S100A8/S100A9 in MSC marked disease progression toward the fibrotic phase in murine models and in patient stroma and plasma. Tasquinimod, a small-molecule inhibiting S100A8/S100A9 signaling, significantly ameliorated the MPN phenotype and fibrosis in JAK2V617F-mutated murine models, highlighting that S100A8/S100A9 is an attractive therapeutic target in MPNs.
Topics: Alarmins; Animals; Bone Marrow; Humans; Mesenchymal Stem Cells; Mice; Myeloproliferative Disorders; Primary Myelofibrosis
PubMed: 33301706
DOI: 10.1016/j.stem.2020.11.004 -
Nature Reviews. Immunology Jun 2017Mitochondrial DNA (mtDNA) - which is well known for its role in oxidative phosphorylation and maternally inherited mitochondrial diseases - is increasingly recognized as... (Review)
Review
Mitochondrial DNA (mtDNA) - which is well known for its role in oxidative phosphorylation and maternally inherited mitochondrial diseases - is increasingly recognized as an agonist of the innate immune system that influences antimicrobial responses and inflammatory pathology. On entering the cytoplasm, extracellular space or circulation, mtDNA can engage multiple pattern-recognition receptors in cell-type- and context-dependent manners to trigger pro-inflammatory and type I interferon responses. Here, we review the expanding research field of mtDNA in innate immune responses to highlight new mechanistic insights and discuss the physiological and pathological relevance of this exciting area of mitochondrial biology.
Topics: Alarmins; Animals; DNA, Mitochondrial; Humans; Immunity, Innate; Inflammation
PubMed: 28393922
DOI: 10.1038/nri.2017.21 -
Allergy Feb 2023The alarmin cytokines thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 are epithelial cell-derived mediators that contribute to the pathobiology and... (Review)
Review
The alarmin cytokines thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 are epithelial cell-derived mediators that contribute to the pathobiology and pathophysiology of asthma. Released from airway epithelial cells exposed to environmental triggers, the alarmins drive airway inflammation through the release of predominantly T2 cytokines from multiple effector cells. The upstream positioning of the alarmins is an attractive pharmacological target to block multiple T2 pathways important in asthma. Blocking the function of TSLP inhibits allergen-induced responses including bronchoconstriction, airway hyperresponsiveness, and inflammation, and subsequent clinical trials of an anti-TSLP monoclonal antibody, tezepelumab, in asthma patients demonstrated improvements in lung function, airway responsiveness, inflammation, and importantly, a reduction in the rate of exacerbations. Notably, these improvements were observed in patients with T2-high and with T2-low asthma. Clinical trials blocking IL-33 and its receptor ST2 have also shown improvements in lung function and exacerbation rates; however, the impact of blocking the IL-33/ST2 axis in T2-high versus T2-low asthma is unclear. To date, there is no evidence that IL-25 blockade is beneficial in asthma. Despite the considerable overlap in the cellular functions of IL-25, IL-33, and TSLP, they appear to have distinct roles in the immunopathology of asthma.
Topics: Humans; Cytokines; Alarmins; Interleukin-33; Interleukin-1 Receptor-Like 1 Protein; Asthma; Thymic Stromal Lymphopoietin; Inflammation
PubMed: 36463491
DOI: 10.1111/all.15609 -
Frontiers in Immunology 2022The exposure of the airway epithelium to external stimuli such as allergens, microbes, and air pollution triggers the release of the alarmin cytokines IL-25, IL-33 and... (Review)
Review
The exposure of the airway epithelium to external stimuli such as allergens, microbes, and air pollution triggers the release of the alarmin cytokines IL-25, IL-33 and thymic stromal lymphopoietin (TSLP). IL-25, IL-33 and TSLP interact with their ligands, IL-17RA, IL1RL1 and TSLPR respectively, expressed by hematopoietic and non-hematopoietic cells including dendritic cells, ILC2 cells, endothelial cells, and fibroblasts. Alarmins play key roles in driving type 2-high, and to a lesser extent type 2-low responses, in asthma. In addition, studies in which each of these three alarmins were targeted in allergen-challenged mice showed decreased chronicity of type-2 driven disease. Consequently, ascertaining the mechanism of activity of these upstream mediators has implications for understanding the outcome of targeted therapies designed to counteract their activity and alleviate downstream type 2-high and low effector responses. Furthermore, identifying the factors which shift the balance between the elicitation of type 2-high, eosinophilic asthma and type-2 low, neutrophilic-positive/negative asthma by alarmins is essential. In support of these efforts, observations from the NAVIGATOR trial imply that targeting TSLP in patients with tezepelumab results in reduced asthma exacerbations, improved lung function and control of the disease. In this review, we will discuss the mechanisms surrounding the secretion of IL-25, IL-33, and TSLP from the airway epithelium and how this influences the allergic airway cascade. We also review in detail how alarmin-receptor/co-receptor interactions modulate downstream allergic inflammation. Current strategies which target alarmins, their efficacy and inflammatory phenotype will be discussed.
Topics: Mice; Animals; Alarmins; Interleukin-33; Immunity, Innate; Endothelial Cells; Lymphocytes; Asthma; Cytokines; Allergens; Epithelial Cells; Interleukin-1 Receptor-Like 1 Protein
PubMed: 36311787
DOI: 10.3389/fimmu.2022.975914 -
Gastroenterology May 2019Acute pancreatitis is an inflammatory disorder of the exocrine pancreas associated with tissue injury and necrosis. The disease can be mild, involving only the pancreas,... (Review)
Review
Acute pancreatitis is an inflammatory disorder of the exocrine pancreas associated with tissue injury and necrosis. The disease can be mild, involving only the pancreas, and resolve spontaneously within days or severe, with systemic inflammatory response syndrome-associated extrapancreatic organ failure and even death. Importantly, there are no therapeutic agents currently in use that can alter the course of the disease. This article emphasizes emerging findings that stressors (environmental and genetic) that cause acute pancreatitis initially cause injury to organelles of the acinar cell (endoplasmic reticulum, mitochondria, and endolysosomal-autophagy system), and that disorders in the functions of the organelles lead to inappropriate intracellular activation of trypsinogen and inflammatory pathways. We also review emerging work on the role of damage-associated molecular patterns in mediating the local and systemic inflammatory response in addition to known cytokines and chemokine pathways. In the review, we provide considerations for correction of organelle functions in acute pancreatitis to create a discussion for clinical trial treatment and design options.
Topics: Acute Disease; Alarmins; Animals; Cytokines; Humans; Inflammation Mediators; Organelles; Pancreas; Pancreatitis; Prognosis; Signal Transduction
PubMed: 30660726
DOI: 10.1053/j.gastro.2018.11.082