Eugenol alleviates the symptoms of experimental autoimmune encephalomyelitis in mice by suppressing inflammatory responses.

Eugenol is a principal compound in essential clove oil, known for its anti-inflammatory and antioxidant properties. While recent studies have demonstrated its neuroprotective effects on central nervous system (CNS) injuries, such as brain ischemia/reperfusion injuries, but its potential impact on multiple sclerosis (MS), an autoimmune disease of the CNS, has not yet been explored. We evaluated the therapeutic effects of eugenol on experimental autoimmune encephalomyelitis (EAE), an established animal model of MS. EAE was induced in C57BL/6 mice using the myelin oligodendrocyte glycoprotein (MOG)35-55 peptide. Clinical symptoms, including paralysis, were monitored daily, and levels of pro-inflammatory mediators were evaluated using real-time quantitative polymerase chain reaction, Western blot analyses, and immunohistochemistry. Daily oral administration of eugenol to MOG-induced EAE mice led to a notable decline in the severity of clinical symptoms. Eugenol inhibited EAE-related immune cell infiltration and the production of pro-inflammatory mediators. Histological examinations confirmed its ability to mitigate inflammation and demyelination in the spinal cord post-EAE induction. Eugenol alleviates neuroinflammation in the spinal cords of EAE-induced mice, primarily through anti-inflammatory action.

Differential In Vivo Effects on Cancer Models by Recorded Magnetic Signals Derived From a Healing Technique.

Previous research on "healing-with-intent" has reasonably demonstrated the validity of the phenomenon at least when a human healer is present and involved. However, in order for healing to be adopted into more conventional therapies, it must be able to be made scalable. The present study tests the effects of a scalable recording of the Bengston Healing Method on 3 cancer models. BalbC mice engrafted with 4T1 breast cancer cells, C57BL mice with melanoma B16 cells, and C3H mice with bladder MBT-2 wells were exposed to a recording of healing intent for 4 hours/day for approximately 1 month. In the breast cancer model, there was significant tumor suppression and a reduction of anemia marker HCT in treated vs control mice. In the melanoma model, there were no significant differences except for a reduction in platelet count among the treated mice. For unknown reasons, tumor growth never became evident in the bladder cancer model. While the effects of the recording seem to vary by model, there appears reason to pursue scalable delivery systems in multiple models and with multiple doses.

[Epstein-Barr virus-associated lymphoproliferative disorders after BNT162b2 mRNA COVID-19 vaccination].

Epstein-Barr virus-associated lymphoproliferative disorders (EBV-LPD) is a rare disease characterized by persistent or recurrent inflammation accompanied by EBV infection of T or NK cells that is not self-limiting, and it is fatal, if untreated. After receiving the first dose of the BNT162b2 mRNA COVID-19 vaccine, a 79-year-old male presented to the hospital with a 2-week history of fever. Laboratory results indicated pancytopenia, elevated liver transaminase levels, hyperferritinemia, and hypofibrinogenemia. Computed tomography revealed hepatosplenomegaly, but lymphadenopathy was not observed. A bone marrow biopsy, a random skin biopsy, and a liver biopsy revealed no malignancy, but an infectious evaluation revealed EBV viremia (5.19 Log IU/ml). Flow cytometry and RT-PCR revealed that the EBV genome was localized in NK cells, suggesting the diagnosis of EBV-NK-LPD. We administered prednisolone, intravenous immunoglobulin, and etoposide, but the EBV-DNA load failed to decrease, and he died 2 months later. Recently, case reports of COVID-19 vaccination-related hemophagocytic lymphohistiocytosis have been published. Although the mechanisms and risk factors for EBV-LPD after BNT162b2 mRNA COVID-19 vaccination remain unknown, it is important to note the possibility of reactivation of EBV after COVID-19 vaccination to initiate early and targeted therapy.

The helminth derived peptide FhHDM-1 redirects macrophage metabolism towards glutaminolysis to regulate the pro-inflammatory response.

We have previously identified an immune modulating peptide, termed FhHDM-1, within the secretions of the liver fluke, Fasciola hepatica, which is sufficiently potent to prevent the progression of type 1 diabetes and multiple sclerosis in murine models of disease. Here, we have determined that the FhHDM-1 peptide regulates inflammation by reprogramming macrophage metabolism. Specifically, FhHDM-1 switched macrophage metabolism to a dependence on oxidative phosphorylation fuelled by fatty acids and supported by the induction of glutaminolysis. The catabolism of glutamine also resulted in an accumulation of alpha ketoglutarate (α-KG). These changes in metabolic activity were associated with a concomitant reduction in glycolytic flux, and the subsequent decrease in TNF and IL-6 production at the protein level. Interestingly, FhHDM-1 treated macrophages did not express the characteristic genes of an M2 phenotype, thereby indicating the specific regulation of inflammation, as opposed to the induction of an anti-inflammatory phenotype per se. Use of an inactive derivative of FhHDM-1, which did not modulate macrophage responses, revealed that the regulation of immune responses was dependent on the ability of FhHDM-1 to modulate lysosomal pH. These results identify a novel functional association between the lysosome and mitochondrial metabolism in macrophages, and further highlight the significant therapeutic potential of FhHDM-1 to prevent inflammation.

Unique insertion/deletion polymorphisms within histidine-rich region of histidine-rich glycoprotein in Thoroughbred horses.

Histidine-rich glycoprotein (HRG) is abundant plasma protein with various effects on angiogenesis, coagulation, and immune responses. Previously, we identified the base and amino acid sequences of equine HRG (eHRG) and revealed that eHRG regulates neutrophil functions. In this study, we first conducted a large-scale gene analysis with DNA samples extracted from 1700 Thoroughbred horses and identified unique insertion/deletion polymorphisms in the histidine-rich region (HRR) of eHRG. Here we report two types of polymorphisms (deletion type 1 [D1] and deletion type 2 [D2]) containing either a 45 bp or 90 bp deletion in the HRR of eHRG, and five genotypes of eHRG (insertion/insertion [II], ID1, ID2, D1D1, and D1D2) in Thoroughbred horses. Allele frequency of I, D1, and D2, was 0.483, 0.480, and 0.037 and the incidence of each genotype was II: 23.4%, ID1: 46.2%, ID2: 3.6%, D1D1: 23.1%, and D1D2: 3.7%, respectively. The molecular weights of each plasma eHRG protein collected from horses with each genotype was detected as bands of different molecular size, which corresponded to the estimated amino acid sequence. The nickel-binding affinity of the D1 or D2 deletion eHRG was reduced, indicating a loss of function at the site. eHRG proteins show a variety of biological and immunological activities in vivo, and HRR is its active center, suggesting that genetic polymorphisms in eHRG may be involved in the performance in athletic ability, productivity, and susceptibility to infectious diseases in Thoroughbred horses.

Neurogenic pulmonary edema caused by right insular cortex infarction.

We report a case of neurogenic pulmonary edema (NPE) caused by middle cerebral artery infarction involving the right insular cortex. Hyperactivity of the insular cortex, which regulates sympathetic function, can cause NPE. The NPE should be considered in the differential diagnosis of dyspneic patients with insular cortex infarction.

Oral Administration of Meloxicam and Flunixin Meglumine Have Similar Analgesic Effects After Lipopolysaccharide-Induced Inflammatory Response in Thoroughbred Horses.

Flunixin meglumine (FM), a nonselective cyclooxygenase (COX) inhibitor, is most frequently selected for the treatment of equine systemic inflammatory response syndrome (SIRS)/endotoxemia. However, FM has considerable adverse effects on gastrointestinal function. The aims of this study were to compare the effect of meloxicam (MX), a COX-2 selective inhibitor commonly used in equine clinical practice, with FM, and to investigate the potential for clinical application in horses with SIRS/endotoxemia. Fifteen horses were divided into three groups of five and orally administered MX (0.6 mg/kg), FM (1.1 mg/kg), or saline as placebo at 30 minutes after LPS challenge. Clinical parameters, including behavioral pain scores, were recorded and blood for clinical pathological data was collected at various times from 60 minutes before to 420 minutes after LPS infusion. The pain score were significantly lower in both the MX and FM groups than in the placebo group, with no significant difference between them. Body temperature was significantly lower in the MX and FM groups than in the placebo group. Heart rates and respiratory rates, hoof wall surface temperature, and leukocyte counts changed similarly between the MX and FM groups. TNF-α and cortisol were lower in the FM group than in the MX group. The results suggest that MX suppresses the inflammatory response after LPS infusion and has an analgesic effect similar to that of FM. Given the adverse effects of nonselective COX inhibitors, clinical application of MX may be beneficial in horses with SIRS/endotoxemia.

Surfactant protein D: A useful biomarker for distinguishing COVID-19 pneumonia from COVID-19 pneumonia-like diseases.

Introduction: Computed tomography is useful for the diagnosis of coronavirus disease (COVID-19) pneumonia. However, many types of interstitial lung diseases and even bacterial pneumonia can show abnormal chest shadows that are indistinguishable from those observed in COVID-19 pneumonia. Thus, it is necessary to identify useful biomarkers that can efficiently distinguish COVID-19 pneumonia from COVID-19 pneumonia-like diseases. Herein, we investigated the usefulness of serum Krebs von den Lungen 6 (KL-6) and surfactant protein D (SP-D) for identifying patients with COVID-19 pneumonia among patients with abnormal chest shadows consistent with COVID-19 pneumonia. Method: This was a retrospective cohort study of consecutive patients who underwent evaluation of serum KL-6 and SP-D at a single center from February 2019 to December 2020. A total of 54 patients with COVID-19 pneumonia and 65 patients with COVID-19 pneumonia-like diseases were enrolled in this study from the source population. Serum KL-6 and SP-D levels in both groups were analyzed. Result: The serum levels of KL-6 and SP-D in patients with COVID-19 pneumonia were significantly lower than those in patients with COVID-19 pneumonia-like disease (median [interquartile range]: 208.5 [157.5-368.5] U/ml vs. 430 [284.5-768.5] U/ml, p < 0.0001 and 24.7 [8.6-51.0] ng/ml vs. 141 [63.7-243.5] ng/ml, p < 0.0001, respectively). According to receiver operating characteristic (ROC) analysis, the areas under the ROC curves (95% confidence intervals) of serum KL-6 and SP-D levels for distinguishing COVID-19 pneumonia from COVID-19 pneumonia-like diseases were 0.761 (0.675-0.847) and 0.874 (0.812-0.936), respectively. The area under the ROC curve of serum SP-D was significantly larger than that of serum KL-6 (p = 0.0213), suggesting that serum SP-D can more efficiently distinguish COVID-19 pneumonia from COVID-19 pneumonia-like diseases. Conclusion: Serum SP-D is a promising biomarker for distinguishing COVID-19 pneumonia from COVID-19 pneumonia-like diseases. Serum SP-D can be useful for the management of patients with abnormal chest shadow mimicking COVID-19 pneumonia.

Subcutaneous abscess due to empyema necessitans caused by Porphyromonas gingivalis in a patient with periodontitis.

Empyema necessitans is a rare empyema complication characterized by an extension of empyema out of the pleural space into the subcutaneous tissues of the chest wall. We herein report a case of empyema necessitans that presented as a subcutaneous chest wall abscess caused by Porphyromonas gingivalis (P. gingivalis), an important anaerobic periodontal pathogen, in a 74-year-old woman with periodontitis. The patient was admitted to our hospital with a painful soft tissue mass in the chest wall extending from a subpleural lung abscess associated with empyema. Exploratory percutaneous puncture and aspiration of the chest wall mass yielded foul-smelling chocolate-colored pus, which was found to be caused due to infection with P. gingivalis. Treatment with antibacterials resulted in a relapse of empyema necessitans requiring a second admission 1 month later. An additive treatment with surgical open drainage and decortication of the subcutaneous abscess successfully cured the abscess. Physicians must be aware of emphysema necessitans as an etiology of a chest wall mass and should consider periodontitis as a source of infection.

Droplet impact of blood and blood simulants on a solid surface: Effect of the deformability of red blood cells and the elasticity of plasma.

The impact of blood droplets onto a solid wall is of great importance for bloodstain pattern analysis in forensic science. Previous studies suggest that the behaviour of impacting blood is similar to that of a Newtonian fluid, which has a shear viscosity equivalent to that of blood at high shear rates. To understand this important fact, we conducted comparative experiments of droplet impact on a glass surface using whole blood and three solutions with a shear viscosity similar to that of blood. Specifically, we used dog's whole blood (deformable red blood cells dispersed in plasma, WB), plasma with non-deformable resin particles (PwP), glycerol and water with resin particles (GWwP), and a commercial blood simulant (hard particles dispersed in a water-based Newtonian solution, BS). Ranges of Reynolds and Weber numbers in our experiments were 550

Osteopontin is a biomarker for early autoimmune uveoretinitis.

Osteopontin (OPN) is an extracellular matrix protein with a diverse range of functions, including roles in cell adhesion, migration, and immunomodulation, which are associated with the modulation of neuroinflammation in the central nervous system. The present study was performed to evaluate the involvement of OPN in the eyes of an experimental autoimmune uveoretinitis (EAU) model. The EAU model was developed by immunization of Lewis rats with interphotoreceptor retinoid-binding protein. The results showed the OPN level was remarkably upregulated in the eye of EAU rats on day 9 post-immunization. The level of CD44, a ligand of OPN, was increased in the ciliary body of EAU rats. Furthermore, OPN was also detected in the ciliary body and activated microglia/macrophages in the EAU retina. The results suggest that OPN was significantly upregulated in the eyes of EAU rats, and that it may be useful as an early biomarker of ocular autoimmune diseases. All animal experiments were approved by the Institutional Animal Care and Use Committee of Jeju National University (approval No. 2020-0012) on March 11, 2020.

Attenuation of Experimental Autoimmune Uveitis in Lewis Rats by Betaine.

Experimental autoimmune uveitis (EAU) is an animal model of human autoimmune uveitis that is characterized by the infiltration of autoimmune T cells with concurrent increases in pro-inflammatory cytokines and reactive oxygen species. This study aimed to assess whether betaine regulates the progression of EAU in Lewis rats. EAU was induced via immunization with the interphotoreceptor retinoid-binding protein (IRBP) and oral administration of either a vehicle or betaine (100 mg/kg) for 9 consecutive days. Spleens, blood, and retinas were sampled from the experimental rats at the time of sacrifice and used for the T cell proliferation assay, serological analysis, real-time polymerase chain reaction, and immunohistochemistry. The T cell proliferation assay revealed that betaine had little effect on the proliferation of splenic T cells against the IRBP antigen in an in vitro assay on day 9 post-immunization. The serological analysis showed that the level of serum superoxide dismutase increased in the betainetreated group compared with that in the vehicle-treated group. The anti-inflammatory effect of betaine was confirmed by the downregulation of pro-inflammation-related molecules, including vascular cell adhesion molecule 1 and interleukin-1ß in the retinas of rats with EAU. The histopathological findings agreed with those of ionized calcium-binding adaptor molecule 1 immunohistochemistry, further verifying that inflammation in the retina and ciliary bodies was significantly suppressed in the betaine-treated group compared with the vehicle-treated group. Results of the present study suggest that betaine is involved in mitigating EAU through anti-oxidation and anti-inflammatory activities.

Early intervention of plasma exchange combined with intensive immunosuppressive treatment for anti-MDA-5 antibody-positive rapidly progressive interstitial pneumonia: Two case reports.

BACKGROUND: Anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5 Ab) has to be reported to often cause rapidly progressive interstitial lung disease (RP-ILD) especially in East Asian countries. Even with the recommended rapid administration of immunosuppressive agents with high-dose corticosteroids, intravenous pulse cyclophosphamide, and calcineurin inhibitors, the prognosis of anti-MDA5 Ab-related RP-ILD is poor. Plasma exchange (PE) has been reported to be effective for steroid-refractory RP-ILD with anti-MDA5 Ab. However, the timing, frequency, and interval of PE for the treatment of RP-ILD with anti-MDA5 Ab have not yet been established. CASE PRESENTATION: We report two cases of RP-ILD with anti-MDA5 Ab treated by early intervention of PE combined with immunosuppressive treatment. Blood biomarkers including titers of anti-MDA5 Ab, serum KL-6 and ferritin were promptly decreased after each session of PE. Clinical symptoms, oxygenation and chest computed tomography abnormalities were completely improved after immunosuppressive treatment with PE. CONCLUSION: Early intervention of PE combined with immunosuppressive treatment may prevent the development to lethal severe respiratory failure in RP-ILD with anti-MDA5 Ab.

Histidine-Rich Glycoprotein Functions as a Dual Regulator of Neutrophil Activity in Horses.

Histidine-rich glycoprotein (HRG) is an abundant plasma protein that has been identified in most mammals. We first identified whole genome sequence of equine HRG (eHRG) and succeeded to purify eHRG from plasma of horses. Since HRG interacts with various ligands, this protein is thought to be involved in immune response, coagulation, and angiogenesis. Systemic inflammatory response syndrome (SIRS) is characterized as a non-specific, clinical, pro-inflammatory immune response that damage organs and tissues in the host. Recent reports revealed that blood HRG levels in human patients with SIRS are approximately 50% lower than those in healthy controls, indicating the use of HRG as a biomarker or treatment for SIRS. SIRS is also a serious issue in equine medicine. In this study, we investigated various effects of eHRG on neutrophil functions, including adhesion, migration, phagocytosis, reactive oxygen species (ROS) production, and lysosome maturation using neutrophils isolated from horses. Microscopic observation showed that the addition of eHRG to the culture diminished adhesion of neutrophils stimulated with LPS. Using the Boyden chamber technique, we showed that eHRG reduced neutrophil chemotaxis induced by recombinant human IL-8. Luminol-dependent chemiluminescence assay demonstrated that eHRG restrained the peak of LPS-promoted ROS production from neutrophils. In contrast, eHRG promoted phagocytic activity evaluated with uptake of fluorescent dye conjugated particles, as well as lysosomal maturation assessed using fluorescent staining for lysosomes of equine neutrophils. These results indicated that eHRG acts as a dual regulator of neutrophils in horses.

Canine mast cell tumour cells regulate tryptophan catabolism via the expression of indoleamine 2,3-dioxygenase.

Indoleamine 2,3-deoxygenase (IDO) produced by cancer cells catabolizes tryptophan (TRP) to kynurenine (KYN) in the environment, resulting induction of cancer immune escape through induction of T cell anergy and enhancement of regulatory T cells. Recently, inhibition of IDO has been recognized as one of therapeutic strategies for human neoplastic diseases. However, there have been few reports about IDO-expressing cancers in dogs. In this study, we attempted to examine whether canine mast cell tumour (MCT) cells express IDO and modulate the concentration of TRP and KYN in the environment. BR, MPT-1.2, and MPT-3 cells were used as canine MCT cells. Expression of IDO was examined with RT-PCR and western blotting. Concentrations of TRP and KYN in the culture medium after incubation with canine MCT cells were detected with liquid chromatography-tandem mass spectrometry. The expression of mRNA and protein of IDO were confirmed in all samples extracted from canine MCT cells. TRP concentration in the culture medium was decreased and that of KYN was increased on incubation with canine MCT cells. The ratio of KYN/TRP, widely considered to represent IDO activity, was also significantly elevated. Moreover, treatment with an IDO inhibitor L-1-methyl-tryptophan (L-1MT) clearly diminished the elevation of KYN/TRP ratio induced by the incubation with canine MCT cells. Our results indicate that canine MCT cells could directly regulate the concentrations of TRP and KYN through expressing IDO, suggesting that canine MCT have an immune escape ability. Therefore, inhibition of IDO might be a novel strategy for the treatment of dogs with MCT.

Glasgow prognostic score for prediction of chemotherapy-triggered acute exacerbation interstitial lung disease in patients with small cell lung cancer.

BACKGROUND: Predicting the incidence of chemotherapy-triggered acute exacerbation of interstitial lung disease (AE-ILD) in patients with lung cancer is important because AE-ILD confers a poor prognosis. The Glasgow prognostic score (GPS), which is an inflammation-based index composed of serum levels of C-reactive protein and albumin, predicts prognosis in patients with small cell lung cancer (SCLC) without ILD. In this study, we investigated AE-ILD and survival outcome based on the GPS in patients with ILD associated with SCLC who were receiving chemotherapy. METHODS: Medical records of patients who received platinum-based first-line chemotherapy between June 2010 and May 2019 were retrospectively reviewed to compare the incidence of AE-ILD and overall survival (OS) between GPS 0, 1, and 2. RESULTS: Among our cohort of 31 patients, six (19.3%) experienced chemotherapy-triggered AE-ILD. The AE-ILD incidence increased from 9.5% to 25.0% and 50.0% with increase in GPS of 0, 1, and 2, respectively. Univariate and multivariate analyses revealed remarkable associations between GPS 2 and both AE-ILD (odds ratio for GPS 2, 18.69; p = 0.046) and prognosis (hazard ratio of GPS 2, 13.52; p = 0.002). Furthermore, median OS in the GPS 0, 1, and 2 groups was 16.2, 9.8, and 7.1 months, respectively (p < 0.001). CONCLUSIONS: Our results suggest that GPS 2 is both a predictor of risk of chemotherapy-triggered AE-ILD and a prognostic indicator in patients with ILD associated with SCLC. We propose that GPS may be used as a guide to distinguish chemotherapy-tolerant patients from those at high risk of AE-ILD.

Short-term infusion of ultralow-dose dopamine in an adult horse with acute kidney injury: A case report.

Much is known regarding a good prognosis of acute kidney injury (AKI) is achieved with adequate, intensive, and early treatment, which leads to acceleration of the renal blood flow rate and associated urination. Low-dose dopamine (1 to 5 µg/kg bwt per min) is a treatment option for AKI in humans but remains controversial for use in horses because of the lack of extensive clinical trial data. A 19-year-old Westfalen horse gelding was referred to the Animal Medical Center with a 1-hour history of mild abdominal pain and anorexia after dressage exercise for 1 hour. Since elevated serum levels of blood urea nitrogen (BUN) and creatinine were found on days 4 and 5, the horse was diagnosed with AKI. In addition to basic hydration therapy with lactated Ringer's solution, we decided to use ultralow-dose dopamine because of the possibilities of the upregulation of dopamine receptors in the affected kidney and general large animal specificity of drug doses. Infusions with 0.04 and 0.02 µg/kg bwt per min for 1 hour on days 6 and 7, respectively, were effective in decreasing serum levels of BUN and creatinine accompanied with a diuretic effect. Thus, short-term infusion of ultralow-dose dopamine may be useful in controlling the renal blood flow rate and clinical conditions in horses with AKI.

Glasgow Prognostic Score predicts chemotherapy-triggered acute exacerbation-interstitial lung disease in patients with non-small cell lung cancer.

BACKGROUND: Interstitial lung disease (ILD) in patients with non-small cell lung cancer (NSCLC) worsens the prognosis for overall survival (OS) due to chemotherapy-triggered acute exacerbation (AE)-ILD. The Glasgow Prognostic Score (GPS), which is based on serum C-reactive protein and albumin levels, has been suggested as a reliable prognostic tool for mortality in cancer patients, including NSCLC. In this study, we investigated whether GPS is a predictor for chemotherapy-triggered AE-ILD and the prognosis in patients with NSCLC and pre-existing ILD. METHODS: We conducted a retrospective review on 56 NSCLC and ILD patients at our hospital who received platinum agent-based treatment as first-line chemotherapy between June 2010 and May 2019. We categorized these patients according to their GPS (0-2) and compared the incidence of chemotherapy-triggered AE-ILD and OS. RESULTS: The GPS 0, 1, and 2 groups included 31, 16, and nine patients, respectively, out of 56. A total of 12 (21.4%) patients showed chemotherapy-triggered AE-ILD. The median OS was at 11.5 months (95% confidence interval: 8.0-15.1). The incidence of chemotherapy-triggered AE-ILD within the first year of chemotherapy in the GPS 0, 1, and 2 groups was three (9.6%), four (25.0%), and five (55.5%), and the median OS time was 16.9, 9.8 and 7.6 months, respectively. Univariate and multivariate analyses indicated that only GPS 2 could predict both chemotherapy-triggered AE-ILD and OS (P < 0.05). CONCLUSIONS: GPS assessment of patients with NSCLC and pre-existing ILD is a valuable prognostic tool for predicting chemotherapy-triggered AE-ILD and OS. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: We found that GPS 2 was an independent risk factor for chemotherapy-triggered AE-ILD and prognosis in patients with ILD associated with NSCLC. WHAT THIS STUDY ADDS: GPS may potentially enable the discrimination of patients tolerant of chemotherapy from those at an increased risk of AE-ILD and predict the prognosis in patients with NSCLC and ILD receiving chemotherapy.

Staphylococcus aureus second immunoglobulin-binding protein drives atopic dermatitis via IL-33.

BACKGROUND: Staphylococcus aureus is the dominant infective trigger of atopic dermatitis (AD). How this bacterium drives type 2 allergic pathology in the absence of infection in patients with AD is unclear. OBJECTIVE: We sought to identify the S aureus-derived virulence factor(s) that initiates the cutaneous type 2-promoting immune response responsible for AD. METHODS: In vitro human keratinocyte cell culture, ex vivo human skin organ explants, and the eczema-prone Nishiki-nezumi Cinnamon/Tokyo University of Agriculture and Technology strain mouse were used as model systems to assess type 2-promoting immune responses to S aureus. Identification of the bioactive factor was accomplished using fast protein liquid chromatography and mass spectrometry. Bioactivity was confirmed by cloning and expression in an Escherichia coli vector system, and S aureus second immunoglobulin-binding protein (Sbi) mutant strains confirming loss of activity. RESULTS: S aureus was unique among staphylococcal species in its ability to induce the rapid release of constitutive IL-33 from human keratinocytes independent of the Toll-like receptor pathway. Using the eczema-prone Nishiki-nezumi Cinnamon/Tokyo University of Agriculture and Technology strain mouse model, we showed that IL-33 was essential for inducing the immune response to S aureus in vivo. By fractionation and candidate testing, we identified Sbi as the predominant staphylococcus-derived virulence factor that directly drives IL-33 release from human keratinocytes. Immunohistology of skin demonstrated that corneodesmosin, a component of corneodesmosomes that form key intercellular adhesive structures in the stratum corneum, was disrupted, resulting in reduction of skin barrier function. CONCLUSIONS: S aureus-derived Sbi is a unique type 2-promoting virulence factor capable of initiating the type 2-promoting cytokine activity underlying AD.

A Rapid Shift from Chronic Hyperoxia to Normoxia Induces Systemic Anaphylaxis via Transient Receptor Potential Ankyrin 1 Channels on Mast Cells.

Extensive activation of mast cells is the major switch that triggers systemic anaphylaxis, resulting in the subsequent release of anaphylactic mediators into circulation. We previously demonstrated that rapid changes in oxygen tension lead to mast cell degranulation, and the released tryptase triggers retinal angiogenesis in a murine oxygen-induced retinopathy model. However, whether a rapid shift from hyperoxia to normoxia (relative hypoxic stress) is a risk factor for systemic anaphylaxis remains unknown. In this study, we demonstrated that the relative hypoxia stress induces systemic mast cell activation via transient receptor potential ankyrin 1 (TRPA1) channels, which immediately leads to hypothermia and increased vascular permeability in adult mice. Although mast cell-deficient or TRPA1-deficient mice did not exhibit anaphylactic symptoms following a rapid sift to normoxia, preinjection with bone marrow-derived cultured mast cells (BMCMCs) derived from wild-type TRPA1-expressing mice restored anaphylactic responses. In addition, we found that the rapid reductions in oxygen tension in a culture atmosphere triggered the degranulation of BMCMCs derived from wild-type TRPA1-expressing mice but not that of BMCMCs derived from TRPA1-deficient mice. In human LAD2 mast cells, the relative hypoxic stress led to the degranulation, which was suppressed by the addition of a TRPA1 inhibitor. Gradual reductions from hyperoxia to normoxia led to no anaphylactic symptoms. Our results demonstrated that TRPA1-triggered mast cell degranulation is a novel pathway that induces anaphylactic shock without Ag-Ab reactions. These findings introduce a potential role for oxygen in inducing mast cell-dependent anaphylaxis and highlight the need to reconsider chronic pure oxygen therapy for anoxic diseases.