Allograft injury mediated by reactive oxygen species: from conserved proteins of Drosophila to acute and chronic rejection of human transplants. Part III: interaction of (oxidative) stress-induced heat shock proteins with toll-like receptor-bearing cells of innate immunity and its consequences for the development of acute and chronic allograft rejection

The effect of m6A methyltransferase METTL3 mediated TMEM30A regulation on tumor energy metabolism and cisplatin anti-tumor activity in oral squamous cell carcinoma

AIMS

Cisplatin (CDDP) is still one of the most commonly used first-line treatments for advanced and recurrent oral squamous cell carcinoma (OSCC) patients in clinical practice. However, the decrease in tumor sensitivity to CDDP weakens its therapeutic effect. There is still limited research on the effect of METTL3-mediated methylation of m6A on CDDP sensitivity in OSCC. TMEM30A widely exists in biomembranes and regulates the lipid asymmetry of the membrane, but there is no report on its function in OSCC. This study aims to explore the specific mechanism by which METTL3 regulates m6A methylation of TMEM30A and affects the occurrence and development of OSCC, and further investigate the effects of METTL3 and TMEM30A on the anti-tumor activity of CDDP.

KEY FINDINGS

In OSCC, METTL3 plays a pro-cancer role and weakens the anti-tumor efficacy of CDDP; METTL3 positively regulates the expression of TMEM30A by m6A methylation modification and binding to TMEM30A; The abnormally high expression of TMEM30A in OSCC not only weakens CDDP sensitivity, but also enhances the malignant evolution of cancer cells, regulates the metabolic balance of ATP and lactate in cells, and is a potential oncogenic gene.

SIGNIFICANCE

TMEM30A promotes malignant progression of tumors through METTL3 mediated m6A methylation modification, participates in maintaining the balance of tumor ATP and lactate metabolism, and reduces the anti-tumor activity of CDDP. TMEM30A is a potential gene target for CDDP anti-tumor activity in OSCC.

Friendly fire: recognition of self by the innate immune system

The innate immune system employs two different strategies to detect pathogens: first, it recognizes microbial components as ligands of pattern recognition receptors (pattern-triggered immunity [PTI]), and second, it detects the activities of pathogen-encoded effectors (effector-triggered immunity [ETI]). Recently, these pathogen-centric concepts were expanded to include sensing of self-derived signals during cellular distress or damage (damage-triggered immunity [DTI]). This extension relied on broadening the PTI model to include damage-associated molecular patterns (DAMPs). However, applying the pattern recognition framework of PTI to DTI overlooks the critical role of sterile activation of ETI pathways. We argue that both PTI and ETI pathways are prone to erroneous detection of self, which is largely attributable to 'friendly fire' rather than protective immune activation. This erroneous activation is inherent to the trade-off between sensitivity and specificity of immune sensing and might be tolerated because its detrimental effects emerge late in life, a phenomenon known as antagonistic pleiotropy.

DAMP sensing and sterile inflammation: intracellular, intercellular and inter-organ pathways

Damage-associated molecular patterns (DAMPs) are endogenous molecules that are released from host cells as a result of cell death or damage. The release of DAMPs in tissues is associated with loss of tissue homeostasis. Sensing of DAMPs by innate immune receptors triggers inflammation, which can be beneficial in initiating the processes that restore tissue homeostasis but can also drive inflammatory diseases. In recent years, the sensing of intracellular DAMPs has received extensive attention in the field of sterile inflammation. However, emerging studies have shown that DAMPs that originate from neighbouring cells, and even from distal tissues or organs, also mediate sterile inflammatory responses. This multi-level sensing of DAMPs is crucial for intercellular, trans-tissue and trans-organ communication. Here, we summarize how DAMP-sensing receptors detect DAMPs from intracellular, intercellular or distal tissue and organ sources to mediate sterile inflammation. We also discuss the possibility of targeting DAMPs or their corresponding receptors to treat inflammatory diseases.

Damage-associated molecular patterns in viral infection: potential therapeutic targets

Frequent viral infections leading to infectious disease outbreaks have become a significant global health concern. Fully elucidating the molecular mechanisms of the immune response against viral infections is crucial for epidemic prevention and control. The innate immune response, the host's primary defense against viral infection, plays a pivotal role and has become a breakthrough in research mechanisms. A component of the innate immune system, damage-associated molecular patterns (DAMPs) are involved in inducing inflammatory responses to viral infections. Numerous DAMPs are released from virally infected cells, activating downstream signaling pathways via internal and external receptors on immune cells. This activation triggers immune responses and helps regulate viral host invasion. This review examines the immune regulatory mechanisms of various DAMPs, such as the S100 protein family, high mobility group box 1 (HMGB1), and heat shock proteins, in various viral infections to provide a theoretical basis for designing novel antiviral drugs.

Targeting inflammasomes and pyroptosis in retinal diseases-molecular mechanisms and future perspectives

Retinal diseases encompass various conditions associated with sight-threatening immune responses and are leading causes of blindness worldwide. These diseases include age-related macular degeneration, diabetic retinopathy, glaucoma and uveitis. Emerging evidence underscores the vital role of the innate immune response in retinal diseases, beyond the previously emphasized T-cell-driven processes of the adaptive immune system. In particular, pyroptosis, a newly discovered programmed cell death process involving inflammasome formation, has been implicated in the loss of membrane integrity and the release of inflammatory cytokines. Several disease-relevant animal models have provided evidence that the formation of inflammasomes and the induction of pyroptosis in innate immune cells contribute to inflammation in various retinal diseases. In this review article, we summarize current knowledge about the innate immune system and pyroptosis in retinal diseases. We also provide insights into translational targeting approaches, including novel drugs countering pyroptosis, to improve the diagnosis and treatment of retinal diseases.

The role of mitochondrial damage-associated molecular patterns in acute pancreatitis

Acute pancreatitis (AP) is one of the most common gastrointestinal tract diseases with significant morbidity and mortality. Current treatments remain unspecific and supportive due to the severity and clinical course of AP, which can fluctuate rapidly and unpredictably. Mitochondria, cellular power plant to produce energy, are involved in a variety of physiological or pathological activities in human body. There is a growing evidence indicating that mitochondria damage-associated molecular patterns (mtDAMPs) play an important role in pathogenesis and progression of AP. With the pro-inflammatory properties, released mtDAMPs may damage pancreatic cells by binding with receptors, activating downstream molecules and releasing inflammatory factors. This review focuses on the possible interaction between AP and mtDAMPs, which include cytochrome c (Cyt c), mitochondrial transcription factor A (TFAM), mitochondrial DNA (mtDNA), cardiolipin (CL), adenosine triphosphate (ATP) and succinate, with focus on experimental research and potential therapeutic targets in clinical practice. Preventing or diminishing the release of mtDAMPs or targeting the mtDAMPs receptors might have a role in AP progression.

DAMPs and DAMP-sensing receptors in inflammation and diseases

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.

Occult hypoperfusion and changes of systemic lipid levels after severe trauma: an analysis in a standardized porcine polytrauma model

BACKGROUND

Occult hypoperfusion describes the absence of sufficient microcirculation despite normal vital signs. It is known to be associated with prolonged elevation of serum lactate and later complications in severely injured patients. We hypothesized that changes in circulating lipids are related to responsiveness to resuscitation. The purpose of this study is investigating the relation between responsiveness to resuscitation and lipidomic course after poly trauma.

METHODS

Twenty-five male pigs were exposed a combined injury of blunt chest trauma, liver laceration, controlled haemorrhagic shock, and femoral shaft fracture. After 1 h, animals received resuscitation and fracture stabilization. Venous blood was taken regularly and 233 specific lipids were analysed. Animals were divided into two groups based on serum lactate level at the end point as an indicator of responsiveness to resuscitation (<2 mmol/L: responder group (R group), ≧2 mmol/L: occult hypoperfusion group (OH group)).

RESULTS

Eighteen animals met criteria for the R group, four animals for the OH group, and three animals died. Acylcarnitines showed a significant increase at 1 h compared to baseline in both groups. Six lipid subgroups showed a significant increase only in R group at 2 h. There was no significant change at other time points.

CONCLUSIONS

Six lipid groups increased significantly only in the R group at 2 h, which may support the idea that they could serve as potential biomarkers to help us to detect the presence of occult hypoperfusion and insufficient resuscitation. We feel that further study is required to confirm the role and mechanism of lipid changes after trauma.

Variation of Plasma Damage-Associated Molecular Patterns in Patients with Advanced Solid Tumors after Standard of Care Systemic Treatment

BACKGROUND

Immunogenic cell death (ICD) is known for releasing damage-associated molecular patterns (DAMPs) from tumor cells. We aimed to find ICD signals by assessing the variation of plasmatic DAMPs (HMGB1, S100A8) before-after standard of care (SoC) systemic treatment in patients with advanced solid tumors.

METHODS

Patients scheduled to start a new line of systemic treatment were included. Plasmatic concentrations of HMGB1 and S100A8 were measured (ng/mL) before and after three months of treatment.

RESULTS

Fifty-two patients were included. Forty-four patients (85%) had metastases, and 8 (15%) were treated for stage III tumors. The most frequent tumor sites were colorectal (35%) and lung (25%). Forty-two patients (81%) received this treatment in the first-line setting. Thirty-six patients (69%) were treated chemotherapy (CT) alone, ten (19%) CT plus targeted therapy, two (3.8%) carboplatin-pemetrexed-pembrolizumab, three (5.8%) pembrolizumab alone and one (1.9%) cetuximab alone. Median plasmatic concentration of S100A8 was significantly higher before than after treatment in the whole population (3.78 vs. 2.91 ng/mL; p = 0.011) and more markedly in the subgroups of patients who experienced RECIST-assessed tumor response (5.70 vs. 2.63 ng/mL; p = 0.002). Median plasmatic concentration of HMGB1was not significantly different before and after treatment (10.23 vs. 11.85 ng/mL; p = 0.382) and did not differ depending on tumor response. Median PFS was not significantly different between patients whose plasma HMBG1 concentration decreased or increased (8.0 vs. 10.6 months; p = 0.29) after treatment. Median PFS was significantly longer in those patients in whom the plasma concentration of S100A8 decreased after treatment (12 vs. 4.7 months; p < 0.001). Median OS was not significantly different between patients whose plasma HMBG1 concentration decreased or increased (13.1 vs. 14.7 months; p = 0.46) after treatment. Median OS was significantly longer in those patients in whom the plasma concentration of S100A8 decreased after treatment (16.7 vs. 9.0 months; p < 0.001).

CONCLUSIONS

Signals of ICD were not observed. S100A8 behaves as an inflammatory marker with decreased concentration after treatment, mostly in RECIST-responders. PFS and OS were significantly prolonged in those patients who experienced a decrease of S100A8 compared with those patients who experienced increase of plasma S100A8 at three months.

Role of DAMPs and cell death in autoimmune diseases: the example of multiple sclerosis

Multiple sclerosis is a chronic neuroinflammatory demyelinating disease of the central nervous system (CNS) of unknown etiology and still incompletely clarified pathogenesis. The disease is generally considered a disorder resulting from a complex interplay between environmental risk factors and predisposing causal genetic variants. To examine the etiopathogenesis of the disease, two complementary pre-clinical models are currently discussed: the "outside-in" model proposing a peripherally elicited inflammatory/autoimmune attack against degraded myelin as the cause of the disease, and the "inside-out" paradigm implying a primary cytodegenerative process of cells in the CNS that triggers secondary reactive inflammatory/autoimmune responses against myelin debris. In this review, the integrating pathogenetic role of damage-associated molecular patterns (DAMPs) in these two scenario models is examined by focusing on the origin and sources of these molecules, which are known to promote neuroinflammation and, via activation of pattern recognition receptor-bearing antigen-presenting cells, drive and shape autoimmune responses. In particular, environmental factors are discussed that are conceptually defined as agents which produce endogenous DAMPs via induction of regulated cell death (RCD) or act themselves as exogenous DAMPs. Indeed, in the field of autoimmune diseases, including multiple sclerosis, recent research has focused on environmental triggers that cause secondary events in terms of subroutines of RCD, which have been identified as prolific sources of DAMPs. Finally, a model of a DAMP-driven positive feed-forward loop of chronic inflammatory demyelinating processes is proposed, aimed at reconciling the competing "inside-out" and "outside-in" paradigms.

Vascular Grafts: Technology Success/Technology Failure

Vascular prostheses (grafts) are widely used for hemodialysis blood access, trauma repair, aneurism repair, and cardiovascular reconstruction. However, smaller-diameter (≤4 mm) grafts that would be valuable for many reconstructions have not been achieved to date, although hundreds of papers on small-diameter vascular grafts have been published. This perspective article presents a hypothesis that may open new research avenues for the development of small-diameter vascular grafts. A historical review of the vascular graft literature and specific types of vascular grafts is presented focusing on observations important to the hypothesis to be presented. Considerations in critically reviewing the vascular graft literature are discussed. The hypothesis that perhaps the "biocompatible biomaterials" comprising our vascular grafts-biomaterials that generate dense, nonvascularized collagenous capsules upon implantation-may not be all that biocompatible is presented. Examples of materials that heal with tissue reconstruction and vascularity, in contrast to the fibrotic encapsulation, are offered. Such prohealing materials may lead the way to a new generation of vascular grafts suitable for small-diameter reconstructions.

AllergoOncology: Danger signals in allergology and oncology: A European Academy of Allergy and Clinical Immunology (EAACI) Position Paper

The immune system interacts with many nominal 'danger' signals, endogenous danger-associated (DAMP), exogenous pathogen (PAMP) and allergen (AAMP)-associated molecular patterns. The immune context under which these are received can promote or prevent immune activating or inflammatory mechanisms and may orchestrate diverse immune responses in allergy and cancer. Each can act either by favouring a respective pathology or by supporting the immune response to confer protective effects, depending on acuity or chronicity. In this Position Paper under the collective term danger signals or DAMPs, PAMPs and AAMPs, we consider their diverse roles in allergy and cancer and the connection between these in AllergoOncology. We focus on their interactions with different immune cells of the innate and adaptive immune system and how these promote immune responses with juxtaposing clinical outcomes in allergy and cancer. While danger signals present potential targets to overcome inflammatory responses in allergy, these may be reconsidered in relation to a history of allergy, chronic inflammation and autoimmunity linked to the risk of developing cancer, and with regard to clinical responses to anti-cancer immune and targeted therapies. Cross-disciplinary insights in AllergoOncology derived from dissecting clinical phenotypes of common danger signal pathways may improve allergy and cancer clinical outcomes.

Damage associated molecular patterns and neutrophil extracellular traps in acute pancreatitis

Previous researches have emphasized a trypsin-centered theory of acute pancreatitis (AP) for more than a century. With additional studies into the pathogenesis of AP, new mechanisms have been explored. Among them, the role of immune response bears great importance. Pro-inflammatory substances, especially damage-associated molecular patterns (DAMPs), play an essential role in activating, signaling, and steering inflammation. Meanwhile, activated neutrophils attach great importance to the immune defense by forming neutrophil extracellular traps (NETs), which cause ductal obstruction, premature trypsinogen activation, and modulate inflammation. In this review, we discuss the latest advances in understanding the pathological role of DAMPs and NETs in AP and shed light on the flexible crosstalk between these vital inflammatory mediators. We, then highlight the potentially promising treatment for AP targeting DAMPs and NETs, with a focus on novel insights into the mechanism, diagnosis, and management of AP.

Plant immunity by damage-associated molecular patterns (DAMPs)

Recognition by plant receptors of microbe-associated molecular patterns (MAMPs) and pathogenicity effectors activates immunity. However, before evolving the capacity of perceiving and responding to MAMPs and pathogenicity factors, plants, like animals, must have faced the necessity to protect and repair the mechanical wounds used by pathogens as an easy passage into their tissue. Consequently, plants evolved the capacity to react to damage-associated molecular patterns (DAMPs) with responses capable of functioning also in the absence of pathogens. DAMPs include not only primarily cell wall (CW) fragments but also extracellular peptides, nucleotides and amino acids that activate both local and long-distance systemic responses and, in some cases, prime the subsequent responses to MAMPs. It is conceivable that DAMPs and MAMPs act in synergy to activate a stronger plant immunity and that MAMPs exploit the mechanisms and transduction pathways traced by DAMPs. The interest for the biology and mechanism of action of DAMPs, either in the plant or animal kingdom, is expected to substantially increase in the next future. This review focuses on the most recent advances in DAMPs biology, particularly in the field of CW-derived DAMPs.

Endotracheal lactate reflects lower respiratory tract infections and inflammation in intubated patients

The aim of this study was to assess L-lactate and D-lactate in endotracheal aspirate from intubated patients hospitalized at the intensive care unit and explore their use as diagnostic biomarkers for inflammation and lower respiratory tract infections (LRTI). Tracheal aspirates from 91 intubated patients were obtained at time of intubation and sent for microbiological analyses, neutrophil count, and colorimetric lactate measurements. We compared the concentration of lactate from patients with microbiological verified LRTI or clinical/radiological suspicion of LRTI with a control group. In addition, associations between inflammation and the lactate isomers were examined by correlating L-lactate and D-lactate with sputum neutrophils and clinical assessments. The concentration of L-lactate was increased in aspirates with verified or suspected LRTI (p < 0.001) relative to the control group at Day 0. Connections between L-lactate and inflammation were indicated by the correlation between neutrophils and L-lactate (p < 0.001). We found no increase in sputum D-lactate from patients with verified or suspected LRTI relative to the control group and D-lactate was not correlated with neutrophils. L-lactate was found to be a potential indicator for inflammation and LRTI at the time of intubation. An association was found between neutrophil count and L-lactate. Interestingly, the increase of L-lactate in the control group after intubation may suggest that intubation challenges the host response by inflicting tissue damage or by introducing infectious microbes.

[Patterns of immunological reactions in the pathogenesis of chronic heart failure: review]

The immune system is essential for maintaining the homeostasis. At present, there is convincing evidence for participation of the immune system in the pathogenesis of cardiovascular pathology, including the final step of cardiovascular continuum, heart failure. Objective difficulties in understanding subtle processes of loss of the normal cardiac structure and function are based on the diversity of pathogenetic factors of development and progression of chronic heart failure (CHF) and the involvement of most organs and body systems. Russian and international scientists actively study issues of immune homeostasis, including the efficacy of current immune therapy. At the same time, available reports are largely uncompiled and reflect isolated parts of the immunopathogenesis of cardiovascular diseases. This review focuses on comprehensive elucidation of major patterns of immune processes in the CHF pathogenesis to form an integral view of the problem under study.

Inflammation Regulates the Multi-Step Process of Retinal Regeneration in Zebrafish

The ability to regenerate tissues varies between species and between tissues within a species. Mammals have a limited ability to regenerate tissues, whereas zebrafish possess the ability to regenerate almost all tissues and organs, including fin, heart, kidney, brain, and retina. In the zebrafish brain, injury and cell death activate complex signaling networks that stimulate radial glia to reprogram into neural stem-like cells that repair the injury. In the retina, a popular model for investigating neuronal regeneration, Müller glia, radial glia unique to the retina, reprogram into stem-like cells and undergo a single asymmetric division to generate multi-potent retinal progenitors. Müller glia-derived progenitors then divide rapidly, numerically matching the magnitude of the cell death, and differentiate into the ablated neurons. Emerging evidence reveals that inflammation plays an essential role in this multi-step process of retinal regeneration. This review summarizes the current knowledge of the inflammatory events during retinal regeneration and highlights the mechanisms whereby inflammatory molecules regulate the quiescence and division of Müller glia, the proliferation of Müller glia-derived progenitors and the survival of regenerated neurons.

The Roles of Inflammation in Keloid and Hypertrophic Scars

The underlying mechanisms of wound healing are complex but inflammation is one of the determining factors. Besides its traditional role in combating against infection upon injury, the characteristics and magnitude of inflammation have dramatic impacts on the pathogenesis of scar. Keloids and hypertrophic scars are pathological scars that result from aberrant wound healing. They are characterized by continuous local inflammation and excessive collagen deposition. In this review, we aim at discussing how dysregulated inflammation contributes to the pathogenesis of scar formation. Immune cells, soluble inflammatory mediators, and the related intracellular signal transduction pathways are our three subtopics encompassing the events occurring in inflammation associated with scar formation. In the end, we enumerate the current and potential medicines and therapeutics for suppressing inflammation and limiting progression to scar. Understanding the initiation, progression, and resolution of inflammation will provide insights into the mechanisms of scar formation and is useful for developing effective treatments.

Targeting pyroptosis to regulate ischemic stroke injury: Molecular mechanisms and preclinical evidences

Stroke is one of the leading causes of death worldwide with limited therapies. After ischemic stroke occurs, a robust sterile inflammatory response happens and lasts for days and determines neurological prognosis. Pyroptosis is an inflammatory programmed cell death characterized by cleavage of pore-forming proteins gasdermins as a result of activating caspases and inflammasomes. It has morphological characteristics of rapid plasma-membrane rupture and release of proinflammatory intracellular contents as well as cytokines. Recent researches implicate pyroptosis involvement in the pathogenesis of ischemic stroke and inhibition of pyroptosis attenuates ischemic brain injury. In this review, we discussed molecular mechanisms of pyroptosis, evidences for pyroptosis involvement in different kinds of the central nervous system cells, as well as potential inhibitors for intervention of pyroptosis. Based on the review, we hypothesize the feasibility of therapeutic strategies targeting pyroptosis in the context of ischemic stroke.

Pattern Recognition Receptor-reactivity Screening of Liver Transplant Patients: Potential for Personalized and Precise Organ Matching to Reduce Risks of Ischemia-reperfusion Injury

OBJECTIVE AND BACKGROUND

Pattern recognition receptors (PRRs) on immune and parenchymal cells can detect danger-associated molecular patterns (DAMPs) released from cells damaged during ischemia-reperfusion injury (IRI), in heart attack or stroke settings, but also as an unavoidable consequence of solid organ transplantation. Despite IRI being a significant clinical problem across all solid organ transplants, there are limited therapeutics and patient-specific diagnostics currently available.

METHODS

We screened portal blood samples obtained from 67 human liver transplant recipients both pre- [portal vein (PV) sample] and post-(liver flush; LF) reperfusion for their ability to activate a panel of PRRs, and analyzed this reactivity in relation to biopsy-proven IRI.

RESULTS

PV samples from IRI+ orthotopic liver transplantation (OLT) patients (n = 35) decreased activation of hTLR4- and hTLR9-transfected cells, whereas PV from IRI- patients (n = 32) primarily increased hTLR7 and hNOD2 activation. LF samples from OLT-IRI patients significantly increased activation of hTLR4 and hTLR9 over IRI- LF. In addition, the change from baseline reactivity to hTLR4/9/NOD2 was significantly higher in IRI+ than IRI- OLT patients.

CONCLUSIONS

These results demonstrate that TLR4/7/9 and NOD2 are involved in either promoting or attenuating hepatic IRI, and suggest a diagnostic screening of portal blood for reactivity to these PRRs might prove useful for prediction and/or therapeutic intervention in OLT patients before transplantation.

Use of DAMPs and SAMPs as Therapeutic Targets or Therapeutics: A Note of Caution

This opinion article discusses the increasing attention paid to the role of activating damage-associated molecular patterns (DAMPs) in initiation of inflammatory diseases and suppressing/inhibiting DAMPs (SAMPs) in resolution of inflammatory diseases and, consequently, to the future roles of these novel biomarkers as therapeutic targets and therapeutics. Since controlled production of DAMPs and SAMPs is needed to achieve full homeostatic restoration and repair from tissue injury, only their pathological, not their homeostatic, concentrations should be therapeutically tackled. Therefore, distinct caveats are proposed regarding choosing DAMPs and SAMPs for therapeutic purposes. For example, we discuss the need to a priori identify and define a context-dependent “homeostatic DAMP:SAMP ratio” in each case and a “homeostatic window” of DAMP and SAMP concentrations to guarantee a safe treatment modality to patients. Finally, a few clinical examples of how DAMPs and SAMPs might be used as therapeutic targets or therapeutics in the future are discussed, including inhibition of DAMPs in hyperinflammatory processes (e.g., systemic inflammatory response syndrome, as currently observed in Covid-19), administration of SAMPs in chronic inflammatory diseases, inhibition of SAMPs in hyperresolving processes (e.g., compensatory anti-inflammatory response syndrome), and administration/induction of DAMPs in vaccination procedures and anti-cancer therapy.

Role of Damage-Associated Molecular Patterns in Light of Modern Environmental Research: A Tautological Approach

Two prominent models emerged as a result of intense interdisciplinary discussions on the environmental health paradigm, called the "exposome" concept and the "adverse outcome pathway" (AOP) concept that links a molecular initiating event to the adverse outcome via key events. Here, evidence is discussed, suggesting that environmental stress/injury-induced damage-associated molecular patterns (DAMPs) may operate as an essential integrating element of both environmental health research paradigms. DAMP-promoted controlled/uncontrolled innate/adaptive immune responses reflect the key events of the AOP concept. The whole process starting from exposure to a distinct environmental stress/injury-associated with the presence/emission of DAMPs-up to the manifestation of a disease may be regarded as an exposome. Clinical examples of such a scenario are briefly sketched, in particular, a model in relation to the emerging COVID-19 pandemic, where the interaction of noninfectious environmental factors (e.g., particulate matter) and infectious factors (SARS CoV-2) may promote SARS case fatality via superimposition of both exogenous and endogenous DAMPs.

Immune Sensing of Cell Death through Recognition of Histone Sequences by C-Type Lectin-Receptor-2d Causes Inflammation and Tissue Injury

The immune system monitors the health of cells and is stimulated by necrosis. Here we examined the receptors and ligands driving this response. In a targeted screen of C-type lectin receptors, a Clec2d reporter responded to lysates from necrotic cells. Biochemical purification identified histones, both free and bound to nucleosomes or neutrophil extracellular traps, as Clec2d ligands. Clec2d recognized poly-basic sequences in histone tails and this recognition was sensitive to post-translational modifications of these sequences. As compared with WT mice, Clec2d^-/- mice exhibited reduced proinflammatory responses to injected histones, and less tissue damage and improved survival in a hepatotoxic injury model. In macrophages, Clec2d localized to the plasma membrane and endosomes. Histone binding to Clec2d did not stimulate kinase activation or cytokine production. Rather, histone-bound DNA stimulated endosomal Tlr9-dependent responses in a Clec2d-dependent manner. Thus, Clec2d binds to histones released upon necrotic cell death, with functional consequences to inflammation and tissue damage.

Myosin II Synergizes with F-Actin to Promote DNGR-1-Dependent Cross-Presentation of Dead Cell-Associated Antigens

Conventional type 1 DCs (cDC1s) excel at cross-presentation of dead cell-associated antigens partly because they express DNGR-1, a receptor that recognizes exposed actin filaments on dead cells. In vitro polymerized F-actin can be used as a synthetic ligand for DNGR-1. However, cellular F-actin is decorated with actin-binding proteins, which could affect DNGR-1 recognition. Here, we demonstrate that myosin II, an F-actin-associated motor protein, greatly potentiates the binding of DNGR-1 to F-actin. Latex beads coated with F-actin and myosin II are taken up by DNGR-1⁺ cDC1s, and antigen associated with those beads is efficiently cross-presented to CD8⁺ T cells. Myosin II-deficient necrotic cells are impaired in their ability to stimulate DNGR-1 or to serve as substrates for cDC1 cross-presentation to CD8⁺ T cells. These results provide insights into the nature of the DNGR-1 ligand and have implications for understanding immune responses to cell-associated antigens and for vaccine design.

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Myosin II amplifies the activity of the DNGR-1 ligand F-actin

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Lack of myosin II in donor cells reduces DNGR-1-dependent cross-presentation

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Beads with F-actin and myosin II can target antigens to cDC1 for CD8 T cell priming

DAMP-sensing receptors in sterile inflammation and inflammatory diseases

The innate immune system has the capacity to detect 'non-self' molecules derived from pathogens, known as pathogen-associated molecular patterns, via pattern recognition receptors. In addition, an increasing number of endogenous host-derived molecules, termed damage-associated molecular patterns (DAMPs), have been found to be sensed by various innate immune receptors. The recognition of DAMPs, which are produced or released by damaged and dying cells, promotes sterile inflammation, which is important for tissue repair and regeneration, but can also lead to the development of numerous inflammatory diseases, such as metabolic disorders, neurodegenerative diseases, autoimmune diseases and cancer. Here we examine recent discoveries concerning the roles of DAMP-sensing receptors in sterile inflammation and in diseases resulting from dysregulated sterile inflammation, and then discuss insights into the cross-regulation of these receptors and their ligands.

Self-DNA Sensing Fuels HIV-1-Associated Inflammation

Inflammation, over-reacting innate immunity, and CD4⁺ T cell depletion are hallmarks of HIV-1 infection. Self-DNA is usually not considered in the context of HIV-1-associated inflammation, although self-DNA contributes to inflammation in diverse pathologies, including autoimmune diseases, cancer, multiorgan failure after trauma, and even virus infections. Cells undergoing HIV-1-associated pyroptotic bystander cell death release self-DNA and other damage-associated molecular patterns (DAMPs), including chaperones and histones. In complexes with such DAMPs or extracellular vesicles, self-DNA gains immunogenic potential and becomes accessible to intracellular DNA sensors. Therefore, we hypothesize that self-DNA can contribute to HIV-1-associated inflammation. Self-DNA might not only drive HIV-1-associated 'inflamm-ageing' but also provide new opportunities for 'shock and kill' strategies aimed at eliminating latent HIV-1.

Cytoskeletal Exposure in the Regulation of Immunity and Initiation of Tissue Repair

This article reviews and discusses emerging evidence suggesting an evolutionarily-conserved connection between injury-associated exposure of cytoskeletal proteins and the induction of tolerance to infection, repair of tissue damage and restoration of homeostasis. While differences exist between vertebrates and invertebrates with respect to the receptor(s), cell types, and effector mechanisms involved, the response to exposed cytoskeletal proteins appears to be protective and to rely on a conserved signaling cassette involving Src family kinases, the nonreceptor tyrosine kinase Syk, and tyrosine phosphatases. A case is made for research programs that integrate different model organisms in order to increase the understanding of this putative response to tissue damage.

Origin and Consequences of Necroinflammation

When cells undergo necrotic cell death in either physiological or pathophysiological settings in vivo, they release highly immunogenic intracellular molecules and organelles into the interstitium and thereby represent the strongest known trigger of the immune system. With our increasing understanding of necrosis as a regulated and genetically determined process (RN, regulated necrosis), necrosis and necroinflammation can be pharmacologically prevented. This review discusses our current knowledge about signaling pathways of necrotic cell death as the origin of necroinflammation. Multiple pathways of RN such as necroptosis, ferroptosis, and pyroptosis have been evolutionary conserved most likely because of their differences in immunogenicity. As the consequence of necrosis, however, all necrotic cells release damage associated molecular patterns (DAMPs) that have been extensively investigated over the last two decades. Analysis of necroinflammation allows characterizing specific signatures for each particular pathway of cell death. While all RN-pathways share the release of DAMPs in general, most of them actively regulate the immune system by the additional expression and/or maturation of either pro- or anti-inflammatory cytokines/chemokines. In addition, DAMPs have been demonstrated to modulate the process of regeneration. For the purpose of better understanding of necroinflammation, we introduce a novel classification of DAMPs in this review to help detect the relative contribution of each RN-pathway to certain physiological and pathophysiological conditions.

Extracellular DAMPs in Plants and Mammals: Immunity, Tissue Damage and Repair

Innate immune receptors, well known mediators of response to non-self-molecules and inflammation, also act as mediators of immunity triggered by 'damage-associated molecular patterns' (DAMPs). Pathogen-associated molecular patterns (PAMPs) cause inflammation in mammals and a rapid immune response in plants, while DAMPs trigger more complex responses, including immunity, tissue maintenance and repair. DAMPs, their receptors and downstream transduction mechanisms are often conserved within a kingdom or, due to convergent evolution, are similar across the kingdoms of life. Herein, we describe the dynamics and functionality of specific extracellular DAMP classes and their receptors in immunity, inflammation and repair of tissue damage in plants and mammals.

A Guide to IL-1 family cytokines in adjuvanticity

Growing awareness of the multiplicity of roles for the IL-1 family in immune regulation has prompted research exploring these cytokines in the context of vaccine-induced immunity. While tightly regulated, cytokines of the IL-1 family are normally released in response to cellular stress and in combination with other danger-/damage-associated molecular patterns (DAMPs), triggering potent local and systemic immune responses. In the context of infection or autoimmunity, engagement of IL-1 family receptors links robust innate responses to adaptive immunity. Clinical and experimental evidence has revealed that many vaccine adjuvants induce the release of one or multiple IL-1 family cytokines. The coordinated release of IL-1 family members in response to adjuvant-induced damage or cell death may be a determining factor in the transition from local inflammation to the induction of an adaptive response. Here, we analyse the effects of IL-1 family cytokines on innate and adaptive immunity with a particular emphasis on activation of antigen-presenting cells and induction of T cell-mediated immunity, and we address in detail the contribution of these cytokines to the modes of action of vaccine adjuvants including those currently approved for human use.

Know your enemy, embrace your friend: using omics to understand how plants respond differently to pathogenic and mutualistic microorganisms

Microorganisms, or 'microbes', have formed intimate associations with plants throughout the length of their evolutionary history. In extant plant systems microbes still remain an integral part of the ecological landscape, impacting plant health, productivity and long-term fitness. Therefore, to properly understand the genetic wiring of plants, we must first determine what perception systems plants have evolved to parse beneficial from commensal from pathogenic microbes. In this review, we consider some of the most recent advances in how plants respond at the molecular level to different microbial lifestyles. Further, we cover some of the means by which microbes are able to manipulate plant signaling pathways through altered destructiveness and nutrient sinks, as well as the use of effector proteins and micro-RNAs (miRNAs). We conclude by highlighting some of the major questions still to be answered in the field of plant-microbe research, and suggest some of the key areas that are in greatest need of further research investment. The results of these proposed studies will have impacts in a wide range of plant research disciplines and will, ultimately, translate into stronger agronomic crops and forestry stock, with immune perception and response systems bred to foster beneficial microbial symbioses while repudiating pathogenic symbioses.

Endogenous DAMPs, Category I: Constitutively Expressed, Native Molecules (Cat. I DAMPs)

This chapter provides the reader with a collection of endogenous DAMPs in terms of constitutively expressed native molecules. The first class of this category refers to DAMPs, which are passively released from necrotic cells, and includes the most prominent subclasses of high mobility group box I and heat shock proteins. Further subclasses of DAMPs that are passively released from necrotic cells include S100 proteins, nucleic acids, histones, pro-forms of interleukin-1-family members, mitochondria-derived N-formylated peptides, F-actin, and heme. A particular subclass of these passively released DAMPs are molecules, which indirectly activate the inflammasome, including adenosine-5′-triphosphate, monosodium urate crystals, cholesterol crystals, some lipolytic species, and beta-amyloid. All these passively released DAMPs are characterized by their capability to promote necroinflammatory responses. The second class of this Category I refers to molecules, which are exposed on the surface of stressed cells. They include the subclass of phagocytosis-facilitating molecules such as calreticulin, as well as the subclass of MHC-I-related molecules such as MHC-I-related molecule A and B. These DAMPs are capable of inducing the activation of innate lymphoid cells and unconventional T cells. One of these DAMPs, the major histocompatibility complex I-related molecule A, is shown to act as a bona fide transplantation antigen. In sum, the endogenous constitutively expressed native molecules represent an impressive category of DAMPs with extraordinary properties, which play a critical role in the pathogenesis of many human diseases.

Expression of Mitochondrial-Encoded Genes in Blood Differentiate Acute Renal Allograft Rejection

Despite potent immunosuppression, clinical and biopsy confirmed acute renal allograft rejection (AR) still occurs in 10-15% of recipients, ~30% of patients demonstrate subclinical rejection on biopsy, and ~50% of them can show molecular inflammation, all which increase the risk of chronic dysfunction and worsened allograft outcomes. Mitochondria represent intracellular endogenous triggers of inflammation, which can regulate immune cell differentiation, and expansion and cause antigen-independent graft injury, potentially enhancing the development of acute rejection. In the present study, we investigated the role of mitochondrial DNA encoded gene expression in biopsy matched peripheral blood (PB) samples from kidney transplant recipients. Quantitative PCR was performed in 155 PB samples from 115 unique pediatric (<21 years) and adult (>21 years) renal allograft recipients at the point of AR (n = 61) and absence of rejection (n = 94) for the expression of 11 mitochondrial DNA encoded genes. We observed increased expression of all genes in adult recipients compared to pediatric recipients; separate analyses in both cohorts demonstrated increased expression during rejection, which also differentiated borderline rejection and showed an increasing pattern in serially collected samples (0-3 months prior to and post rejection). Our results provide new insights on the role of mitochondria during rejection and potentially indicate mitochondria as targets for novel immunosuppression.

Dying cells actively regulate adaptive immune responses

Dying cells have an important role in the initiation of CD8⁺ T cell-mediated immunity. The cross-presentation of antigens derived from dying cells enables dendritic cells to present exogenous tissue-restricted or tumour-restricted proteins on MHC class I molecules. Importantly, this pathway has been implicated in multiple autoimmune diseases and accounts for the priming of tumour antigen-specific T cells. Recent data have revealed that in addition to antigen, dying cells provide inflammatory and immunogenic signals that determine the efficiency of CD8⁺ T cell cross-priming. The complexity of these signals has been evidenced by the multiple molecular pathways that result in cell death and that have now been shown to differentially influence antigen transfer and immunity. In this Review, we provide a detailed summary of both the passive and active signals that are generated by dying cells during their initiation of CD8⁺ T cell-mediated immunity. We propose that molecules generated alongside cell death pathways - inducible damage-associated molecular patterns (iDAMPs) - are upstream immunological cues that actively regulate adaptive immunity.

Transplantation and Damage-Associated Molecular Patterns (DAMPs)

Upon solid organ transplantation and during cancer immunotherapy, cellular stress responses result in the release of damage-associated molecular patterns (DAMPs). The various cellular stresses have been characterized in detail over the last decades, but a unifying classification based on clinically important aspects is lacking. Here, we provide an in-depth review of the most recent literature along with a unifying concept of the danger/injury model, suggest a classification of DAMPs, and review the recently elaborated mechanisms that result in the emission of such factors. We further point out the differences in DAMP responses including the release following a heat shock pattern, endoplasmic reticulum stress, DNA damage-mediated DAMP release, and discuss the diverse pathways of regulated necrosis in this respect. The understanding of various forms of DAMPs and the consequences of their different release patterns are prerequisite to associate serum markers of cellular stresses with clinical outcomes.

DAMP-Induced Allograft and Tumor Rejection: The Circle Is Closing

The pathophysiological importance of the immunogenicity of damage-associated molecular patterns (DAMPs) has been pinpointed by their identification as triggers of allograft rejection following release from dying cells, such as after ischemia-reperfusion injury. In cancers, however, this strong trigger of a specific immune response gives rise to the success of cancer immunotherapy. Here, we review the recently literature on the pathophysiological importance of DAMP release and discuss the implications of these processes for allograft rejection and cancer immunotherapy, revealing a striking mechanistic overlap. We conclude that these two fields share a common mechanistic basis of regulated necrosis and inflammation, the molecular characterization of which may be helpful for both oncologists and the transplant community.

Plant immunity triggered by engineered in vivo release of oligogalacturonides, damage-associated molecular patterns

Oligogalacturonides (OGs) are fragments of pectin that activate plant innate immunity by functioning as damage-associated molecular patterns (DAMPs). We set out to test the hypothesis that OGs are generated in planta by partial inhibition of pathogen-encoded polygalacturonases (PGs). A gene encoding a fungal PG was fused with a gene encoding a plant polygalacturonase-inhibiting protein (PGIP) and expressed in transgenic Arabidopsis plants. We show that expression of the PGIP-PG chimera results in the in vivo production of OGs that can be detected by mass spectrometric analysis. Transgenic plants expressing the chimera under control of a pathogen-inducible promoter are more resistant to the phytopathogens Botrytis cinerea, Pectobacterium carotovorum, and Pseudomonas syringae. These data provide strong evidence for the hypothesis that OGs released in vivo act as a DAMP signal to trigger plant immunity and suggest that controlled release of these molecules upon infection may be a valuable tool to protect plants against infectious diseases. On the other hand, elevated levels of expression of the chimera cause the accumulation of salicylic acid, reduced growth, and eventually lead to plant death, consistent with the current notion that trade-off occurs between growth and defense.

How evolution tells us to induce allotolerance

Modern immunology, in many ways, is based on 3 major paradigms: the clonal selection theory (Medawar, Burnet; 1953/1959), the pattern recognition theory (Janeway; 1989), and the danger/injury theory (Matzinger, Land; 1994). The last theory holds that any cell stress and tissue injury including allograft injury, via induction of damage-associated molecular patterns, induces immunity including alloimmunity leading to allograft rejection. On the other hand, the concept precludes that "non-self " per se induces immunity as proposed by the two former theories. Today, the danger/injury model has been largely accepted by immunologists, as documented by a steadily increasing number of publications. In particular, overwhelming evidence in support of the correctness of the model has come from recent studies on the gut microbiota representing a huge assemblage of "non-self. " Here, harmless noninjurious commensal microbes are protected by innate immunity-based immune tolerance whereas intestinal injury-causing pathogenic microbes are immunology attacked. The ability of the immune system to discriminate between harmless beneficial "non-self " to induce tolerance and harmful life-threatening "non-self " to induce immunity has apparently emerged during evolution: Protection of innate immunity-controlled beneficial "non-self " (eg, as reflected by microbiotas but also by the fetus of placental mammals) as well as immune defense responses to injuring/injured "non-self " (eg, as reflected by plant resistance to biotic and abiotic stress and allograft rejection in mammals) evolved under pressure across the tree of life, that is, in plants, lower and higher invertebrates as well as lower and higher vertebrates. And evolution tells us why the overall existence of protected microbiotas really makes sense: It is the formation of the "holobiont, " - a metaorganism - that is, the host plus all of its associated microorganisms that - in terms of a strong unit of selection in evolution - provides that kind of fitness to all species on earth to successfully live, survive and reproduce. In other words: "We all evolve, develop, grow, and reproduce as multigenomic ecosystems! Regarding reproduction, another impressive example of active immunologic protection of "nonself " refers to pregnancy in placental mammals that emerged about 400 millions of years ago. Similar to "non-self " microbiotas, pregnancy in placental mammals reflects an evolution-driven phenomenon on the basis of innate immunity-controlled tolerance induction to semiallogeneic non-injuring/non-injured "non-self " aiming to ensure reproduction! Altogether, the lesson learned from evolution of how to avoid allograft rejection is clear: prevent allograft injury to induce allotolerance, in other words: create a "transplant holobiont. ".

The Role of Damage-Associated Molecular Patterns in Human Diseases: Part I - Promoting inflammation and immunity

There is increasing interest by physicians in the impact of the innate immune system on human diseases. In particular, the role of the molecules that initiate and amplify innate immune pathways, namely damage-associated molecular patterns (DAMPs), is of interest as these molecules are involved in the pathogenesis of many human disorders. The first part of this review identifies five classes of cell stress/tissue injury-induced DAMPs that are sensed by various recognition receptor-bearing cells of the innate immune system, thereby mounting inflammation, promoting apoptosis and shaping adaptive immune responses. The DAMPs activate and orchestrate several innate immune machineries, including inflammasomes and the unfolded protein response that synergistically operates to induce inflammatory, metabolic and adaptive immune pathologies. Two examples of autoimmune diseases are discussed as they represent a typical paradigm of the intimate interplay between innate and adaptive immune responses.

Danger signals - damaged-self recognition across the tree of life

Multicellular organisms suffer injury and serve as hosts for microorganisms. Therefore, they require mechanisms to detect injury and to distinguish the self from the non-self and the harmless non-self (microbial mutualists and commensals) from the detrimental non-self (pathogens). Danger signals are "damage-associated molecular patterns" (DAMPs) that are released from the disrupted host tissue or exposed on stressed cells. Seemingly ubiquitous DAMPs are extracellular ATP or extracellular DNA, fragmented cell walls or extracellular matrices, and many other types of delocalized molecules and fragments of macromolecules that are released when pre-existing precursors come into contact with enzymes from which they are separated in the intact cell. Any kind of these DAMPs enable damaged-self recognition, inform the host on tissue disruption, initiate processes aimed at restoring homeostasis, such as sealing the wound, and prepare the adjacent tissues for the perception of invaders. In mammals, antigen-processing and -presenting cells such as dendritic cells mature to immunostimulatory cells after the perception of DAMPs, prime naïve T-cells and elicit a specific adaptive T-/B-cell immune response. We discuss molecules that serve as DAMPs in multiple organisms and their perception by pattern recognition receptors (PRRs). Ca(2+)-fluxes, membrane depolarization, the liberation of reactive oxygen species and mitogen-activated protein kinase (MAPK) signaling cascades are the ubiquitous molecular mechanisms that act downstream of the PRRs in organisms across the tree of life. Damaged-self recognition contains both homologous and analogous elements and is likely to have evolved in all eukaryotic kingdoms, because all organisms found the same solutions for the same problem: damage must be recognized without depending on enemy-derived molecules and responses to the non-self must be directed specifically against detrimental invaders.

Transfusion-Related Acute Lung Injury: The Work of DAMPs

Current notions in immunology hold that not only pathogen-mediated tissue injury but any injury activates the innate immune system. In principle, this evolutionarily highly conserved, rapid first-line defense system responds to pathogen-induced injury with the creation of infectious inflammation, and non-pathogen-induced tissue injury with 'sterile' tissue inflammation. In this review, evidence has been collected in support of the notion that the transfusion-related acute lung injury induces a 'sterile' inflammation in the lung of transfused patients in terms of an acute innate inflammatory disease. The inflammatory response is mediated by the patient's innate immune cells including lung-passing neutrophils and pulmonary endothelial cells, which are equipped with pattern recognition receptors. These receptors are able to sense injury-induced, damage-associated molecular patterns (DAMPs) generated during collection, processing, and storage of blood/blood components. The recognition process leads to activation of these innate cells. A critical role for a protein complex known as the NLRP3 inflammasome has been suggested to be at the center of such a scenario. This complex undergoes an initial 'priming' step mediated by 1 class of DAMPs and then an 'activating' step mediated by another class of DAMPs to activate interleukin-1beta and interleukin-18. These 2 cytokines then promote, via transactivation, the formation of lung inflammation.

Prevention of intimal hyperplasia employing the cavitary two-layer method in allogeneic rat heart transplantation

BACKGROUND

The development of graft arteriosclerosis is a significant contributor to chronic rejection in organ transplant recipients. The purpose of the present study was to establish whether or not the cavitary two-layer method can prevent graft arteriosclerosis after rat heart transplantation.

METHODS

F-344 rats served as donors to Lewis recipients. Grafts in the control group (group C) were immediately allotransplanted without preservation. Grafts were also transplanted after cold preservation for 3 h in University of Wisconsin solution (group UW), or employing the cavitary two-layer (CTL) method (group TL). In another group (group W), grafts were subjected to 15-min warm ischemia and then transplanted. Grafts damaged by ischemia were also transplanted after preservation for 3 h using CTL (group WTL). We measured intimal thickening (IT) before transplantation and at 30 and 60 d post-transplant and also assessed the expression of heat shock proteins (HSPs).

RESULTS

At 60 d post-transplant, IT in group WTL was significantly lower than in group W (0.30 ± 0.03 versus 0.45 ± 0.04, respectively). In contrast, no significant changes were observed in the cold storage groups. Expression of HSPs 60 and 70 at 60 d in group WTL (25.40% ± 1.64% and 35.96% ± 2.65%, respectively) was reduced compared with group W (46.07% ± 5.84% and 55.11% ± 1.54%, respectively).

CONCLUSIONS

CTL reduces IT induced by warm ischemia in rat heart transplantation, and allows the maintenance of low HSP 60 and 70 expression.

Clinical features of benign paroxysmal positional vertigo in Western Turkey

BACKGROUND

It was the aim of this study to analyze the clinical manifestations, the incidence of each variant and the comorbid conditions of benign paroxysmal positional vertigo (BPPV) as well as the response to treatment.

METHODS

One hundred and fifty-seven patients with BPPV were reviewed prospectively. An extensive neurotologic examination was performed. All patients were treated with an appropriate canalith repositioning maneuver (CRM).

RESULTS

In 138 patients, the posterior canal (PC) was involved, in 14 patients, the horizontal canal (HC), in 2 patients, the anterior canal (AC), and in 3 patients, both the PC and HC. A history of head trauma was identified in 17 patients. In 1 patient sensorineural hearing loss on the affected side and in another bilateral peripheral vestibular loss was present. A history of migraine was reported in 21 cases. A resolution attributable to the first CRM was achieved in 132 patients.

CONCLUSIONS

PC involvement was the most frequent type constituting 87.9% of all BPPV cases. HC, AC and mixed canal types were relatively rare constituting 8.9, 1.3 and 1.9% of the cases, respectively. Response to the first CRM was recorded in 84.1%. Association with migraine was recorded in 13.4% of the patients.

Cyclosporine-induced renal injury induces toll-like receptor and maturation of dendritic cells

BACKGROUND

The toll-like receptor (TLR) is stimulated by not only pathogen-associated molecular patterns but also endogenous TLR ligands provided by injured cells. The influence of cyclosporine A (CsA)-induced renal injury on TLR expression and subsequent signaling pathway was evaluated.

METHODS

Induction of chronic CsA nephropathy was made by administering CsA (15 mg/kg/day) for 28 days in rats. The TLR2 and TLR4 mRNA and protein expression, TLR-signaling pathway (MYD88, NF-kappaB and AP-1), putative TLR ligand (heat shock protein 70 [HSP70]), and maturation of dendritic cells were evaluated in CsA-treated rat kidneys.

RESULTS

Long-term CsA treatment upregulated TLR2 and TLR4 mRNA and protein expression on renal tubular cells, and these were accompanied by increased MYD88, NF-kappaB and AP-1 expression. Putative TLR ligand (HSP70) was also significantly increased in CsA-treated rat kidney compared with vehicle-treated rat kidney. CsA-treatment increased expression of TNF-alpha mRNA, the number of dendritic cells, and expression of MHC class II antigen. Double-labeling of markers of dendritic cells and MHC class II antigen revealed that matured dendritic cells increased in CsA-treated rat kidney.

CONCLUSIONS

CsA-induced renal injury stimulates components of innate immunity, and this finding suggests close association between CsA-induced renal injury and activation of innate immunity.

Ischemia-reperfusion injury activates innate immunity in rat kidneys

BACKGROUND

There is growing evidence of a role of the immune system in the pathophysiology of ischemia-reperfusion (I/R) injury, but the influence of I/R injury on innate immunity is still undetermined.

METHODS

Sprague-Dawley rats were used. I/R injury was induced by clamping both renal arteries for 45 min, and the rats were killed 1, 3, 5, and 7 days later. Activation of innate immunity was evaluated in terms of the expression of toll-like receptor (TLR) 2 or TLR4 mRNAs and protein, by the level of the TLR ligand (heat shock protein [HSP] 70), and maturation of dendritic cells by double-label immunohistochemistry of dendritic cells for major histocompatibility complex (MHC) class II antigen.

RESULTS

I/R injury increased TLR2 and TLR4 mRNA and protein expression, and they were mainly observed on renal tubular cells. I/R injury also produced endogenous TLR ligand (HSP70) on renal tubular cells. I/R injury increased not only the numbers of dendritic cells but also the production of MHC class II antigen in dendritic cells, suggesting maturation of these cells. Activation of innate immunity was observed at day 1, peaked at days 3 to 5 after I/R injury, and thereafter gradually decreased.

CONCLUSIONS

I/R injury rapidly activates the innate immune response.