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.

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.

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.

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.

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.

Oral Administration of Meloxicam Suppresses Low-Dose Endotoxin Challenge-Induced Pain in Thoroughbred Horses.

Nonsteroidal anti-inflammatory drugs such as flunixin meglumine have been used to treat signs of systemic inflammatory conditions, but it is also known to have the side effect to small intestine mucosa. It may be considered to be due to inhibition of both cyclooxygenase (COX)-1 and COX-2. On the other hand, meloxicam is widely used in equine clinical practice and an effective nonsteroidal anti-inflammatory drug with the preferential inhibitory effect on COX-2. However, it has not yet been evaluated in equine systemic inflammation. The aim of this study was to evaluate the effect of meloxicam administered 60 minutes prior lipopolysaccharide (LPS)-induced inflammatory response in five Thoroughbred horses using a crossover test. Clinical parameters including body temperature, heart rate, respiratory rate, behavioral pain score, and hoof wall surface temperature were recorded, and plasma tumor necrosis factor-alpha, cortisol, and leukocyte counts were measured at various times before and after LPS infusion for 420 minutes. At time points 60, 90 (P < .01), 120, and 180 (P < .05) minutes, pain scores were significantly lower in meloxicam-treated horses. There was no significant difference in other parameters. In the present study, we revealed the analgesic effect of meloxicam using an equine low-dose endotoxin model.

Benefits of hesperidin in central nervous system disorders: a review.

Citrus species contain significant amounts of flavonoids that possess antioxidant activities; furthermore, dietary citrus is not associated with adverse effects or cytotoxicity in healthy individuals. Hesperidin, which is an abundant flavanone glycoside in the peel of citrus fruits, possesses a variety of biological capabilities that include antioxidant and anti-inflammatory actions. Over the last few decades, many studies have been investigated the biological actions of hesperidin and its aglycone, hesperetin, as well as their underlying mechanisms. Due to the antioxidant effects of hesperidin and its derivatives, the cardioprotective and anti-cancer effects of these compounds have been widely reviewed. Although the biological activities of hesperidin in neurodegenerative diseases have been evaluated, its potential involvement in a variety of central nervous system (CNS) disorders, including autoimmune demyelinating disease, requires further investigation in terms of the underlying mechanisms. Thus, the present review will focus on the potential role of hesperidin in diverse models of CNS neuroinflammation, including experimental autoimmune encephalomyelitis, with special consideration given to its antioxidant and anti-inflammatory effects in neurodegenerative disease models. Additionally, current evidence provides information regarding the nutraceutical use of hesperidin to prevent various CNS disorders.

Novel Therapeutics for Multiple Sclerosis Designed by Parasitic Worms.

The evolutionary response to endemic infections with parasitic worms (helminth) was the development of a distinct regulatory immune profile arising from the need to encapsulate the helminths while simultaneously repairing tissue damage. According to the old friend's hypothesis, the diminished exposure to these parasites in the developed world has resulted in a dysregulated immune response that contributes to the increased incidence of immune mediated diseases such as Multiple Sclerosis (MS). Indeed, the global distribution of MS shows an inverse correlation to the prevalence of helminth infection. On this basis, the possibility of treating MS with helminth infection has been explored in animal models and phase 1 and 2 human clinical trials. However, the possibility also exists that the individual immune modulatory molecules secreted by helminth parasites may offer a more defined therapeutic strategy.

Selection of reliable reference genes for the normalisation of gene expression levels following time course LPS stimulation of murine bone marrow derived macrophages.

BACKGROUND: Macrophages are key players in the initiation, perpetuation and regulation of both innate and adaptive immune responses. They largely perform these roles through modulation of the expression of genes, especially those encoding cytokines. Murine bone marrow derived macrophages (BMDMs) are commonly used as a model macrophage population for the study of immune responses to pro-inflammatory stimuli, notably lipopolysaccharide (LPS), which may be pertinent to the human situation. Evaluation of the temporal responses of LPS stimulated macrophages is widely conducted via the measurement of gene expression levels by RT-qPCR. While providing a robust and sensitive measure of gene expression levels, RT-qPCR relies on the normalisation of gene expression data to a stably expressed reference gene. Generally, a normalisation gene(s) is selected from a list of "traditional" reference genes without validation of expression stability under the specific experimental conditions of the study. In the absence of such validation, and given that many studies use only a single reference gene, the reliability of data is questionable. RESULTS: The stability of expression levels of eight commonly used reference genes was assessed during the peak (6 h) and resolution (24 h) phases of the BMDM response to LPS. Further, this study identified two additional genes, which have not previously been described as reference genes, and the stability of their expression levels during the same phases of the inflammatory response were validated. Importantly, this study demonstrates that certain "traditional" reference genes are in fact regulated by LPS exposure, and, therefore, are not reliable candidates as their inclusion may compromise the accuracy of data interpretation. Testament to this, this study shows that the normalisation of gene expression data using an unstable reference gene greatly affects the experimental data obtained, and, therefore, the ultimate biological conclusions drawn. CONCLUSION: This study reaffirms the importance of validating reference gene stability for individual experimental conditions. Given that gene expression levels in LPS stimulated macrophages is routinely used to infer biological phenomena that are of relevance to human conditions, verification of reference gene expression stability is crucial.

Mast cell hyperactivity underpins the development of oxygen-induced retinopathy.

Mast cells are classically thought to play an important role in protection against helminth infections and in the induction of allergic diseases; however, recent studies indicate that these cells also contribute to neovascularization, which is critical for tissue remodeling, chronic inflammation, and carcinogenesis. Here, we demonstrate that mast cells are essential for sprouting angiogenesis in a murine model of oxygen-induced retinopathy (OIR). Although mouse strains lacking mast cells did not exhibit retinal neovascularization following hypoxia, these mice developed OIR following infusion of mast cells or after injection of mast cell tryptase (MCT). Relative hypoxia stimulated mast cell degranulation via transient receptor potential ankyrin 1. Subsequent surges in MCT stimulated retinal endothelial cells to produce monocyte chemotactic protein-1 (MCP1) and angiogenic factors, leading to sprouting angiogenesis. Mast cell stabilizers as well as specific tryptase and MCP1 inhibitors prevented the development of OIR in WT mice. Preterm infants with early retinopathy of prematurity had markedly higher plasma MCT levels than age-matched infants without disease, suggesting mast cells contribute to human disease. Together, these results suggest therapies that suppress mast cell activity should be further explored as a potential option for preventing eye diseases and subsequent blindness induced by neovascularization.

Effective induction of death in mesothelioma cells with magnetite nanoparticles under an alternating magnetic field.

With the objective of finding an avenue for development of magnetic hyperthermia as an effective mesothelioma treatment, the influence of heating by magnetite nanoparticles (MNPs) with a diameter of ~40nm, which were incorporated into cells and then subjected to AC magnetic field, on induction of cell death was investigated in all three histological subtypes of human mesothelioma cells (i.e., epithelioid NCI-H28, sarcomatoid NCI-H2052, and biphasic MSTO-211H cells). Cellular uptake of MNPs was observed in all cell types, but the amount of MNPs incorporated per cell into MSTO-211H cells was smaller than in NCI-H28 and NCI-H2052 cells. On the other hand, cell death induced by cellular uptake of MNPs was observed specifically in MSTO-211H cells. Hence, when cells are heated by intracellular MNPs under AC magnetic field, a high degree of cell mortality in NCI-H28 and NCI-H2052 cells is induced by the temperature increase derived from the high amount of intracellular MNPs, but the combination of intracellular heating and cell-type-specific toxicity of MNPs induced high rates of cell death in MSTO-211H cells even at a lower temperature. Almost all of the heated cells were dead after 24-h incubation at 37°C in all histological subtypes. Additionally, higher mortalities were observed in all three types of mesothelioma cells after MNPs-heating, as compared to the heating with a thermostatic bath. Herein, the significance of cellular uptake of MNPs for effectively inducing cell death in mesothelioma has been demonstrated in vitro.

Innate function of house dust mite allergens: robust enzymatic degradation of extracellular matrix at elevated pH.

BACKGROUND: Exposure to the house dust mite Dermatophagoides pteronyssinus (D.p.) increases the risk for developing allergic diseases in humans and their best friends, the dogs. Here, we explored whether this allergenic mite via its enzymes may impact the cutaneous extracellular matrix (ECM), which critically determines epithelial barrier integrity both structurally and functionally. METHODS: Two extracts obtained from either dust-purified or cultured D.p. bodies were used in the present study. To assess the potential impact of D.p. on protein components of the ECM, proteolytic activity of the D.p. extracts were determined by casein and gelatin gel zymography, and their N-acetyl-ß-hexosaminidase activity determined colorimetrically. In addition, IgE-dependent and innate degranulation potential of D.p. was examined in canine MPT-1 mast cells and neurite outgrowth assay using rat pheochromocytoma PC-12 cells. RESULTS: In gel zymography, both extracts digested the substrates casein and gelatin in a dose-dependent manner, especially at alkaline pH, and effective in a wide range of temperatures (30 °C-42 °C). In particular, a 25-kDa band corresponding to Der p 1, the major D.p. allergen for humans, was found enzymatically active in both casein and gelatin gels regardless of the presence of metal ions and of alkaline conditions. Besides protease activity, N-acetyl-ß-hexosaminidase activity was detected in both extracts, suggesting that D.p. affects the cutaneous ECM through deteriorating both proteins and glycosaminoglycans. While both D.p. extracts induced IgE-dependent mast cell degranulation, much less innate effects on mast- and neuronal cells were observed. CONCLUSIONS: Our data highlight that D.p. is a robust source of several distinct enzymes with protease- and N-acetyl-ß-hexosaminidase activities. In alkaline milieu they can degrade components of the ECM. Therefore, D.p. may contribute to epithelial barrier disruption especially when the skin surface pH is elevated.

A parasite-derived 68-mer peptide ameliorates autoimmune disease in murine models of Type 1 diabetes and multiple sclerosis.

Helminth parasites secrete molecules that potently modulate the immune responses of their hosts and, therefore, have potential for the treatment of immune-mediated human diseases. FhHDM-1, a 68-mer peptide secreted by the helminth parasite Fasciola hepatica, ameliorated disease in two different murine models of autoimmunity, type 1 diabetes and relapsing-remitting immune-mediated demyelination. Unexpectedly, FhHDM-1 treatment did not affect the proliferation of auto-antigen specific T cells or their production of cytokines. However, in both conditions, the reduction in clinical symptoms was associated with the absence of immune cell infiltrates in the target organ (islets and the brain tissue). Furthermore, after parenteral administration, the FhHDM-1 peptide interacted with macrophages and reduced their capacity to secrete pro-inflammatory cytokines, such as TNF and IL-6. We propose this inhibition of innate pro-inflammatory immune responses, which are central to the initiation of autoimmunity in both diseases, prevented the trafficking of autoreactive lymphocytes from the periphery to the site of autoimmunity (as opposed to directly modulating their function per se), and thus prevented tissue destruction. The ability of FhHDM-1 to modulate macrophage function, combined with its efficacy in disease prevention in multiple models, suggests that FhHDM-1 has considerable potential as a treatment for autoimmune diseases.

Development of new therapy for canine mammary cancer with recombinant measles virus.

Oncolytic virotherapy is a promising treatment strategy for cancer. We previously generated a recombinant measles virus (rMV-SLAMblind) that selectively uses a poliovirus receptor-related 4 (PVRL4/Nectin4) receptor, but not signaling lymphocyte activation molecule (SLAM). We demonstrated that the virus exerts therapeutic effects against human breast cancer cells. Here, we examined the applicability of rMV-SLAMblind to treating canine mammary cancers (CMCs). We found that the susceptibilities of host cells to rMV-SLAMblind were dependent on canine Nectin-4 expression. Nectin-4 was detected in four of nine CMC cell lines. The rMV-SLAMblind efficiently infected those four Nectin-4-positive cell lines and was cytotoxic for three of them (CF33, CHMm, and CTBm). In vivo experiment showed that the administration of rMV-SLAMblind greatly suppressed the progression of tumors in mice xenografted with a CMC cell line (CF33). Immunohistochemistry revealed that canine Nectin-4 was expressed in 45% of canine mammary tumors, and the tumor cells derived from one clinical specimen were efficiently infected with rMV-SLAMblind. These results suggest that rMV-SLAMblind infects CMC cells and displays antitumor activity in vitro, in xenografts, and ex vivo. Therefore, oncolytic virotherapy with rMV-SLAMblind can be a novel method for treating CMCs.

Skin pH Is the Master Switch of Kallikrein 5-Mediated Skin Barrier Destruction in a Murine Atopic Dermatitis Model.

Elevated skin surface pH has been reported in patients with atopic dermatitis. In this study, we explored the role of skin pH in the pathogenesis of atopic dermatitis using the NC/Tnd murine atopic dermatitis model. Alkalinization of the skin of asymptomatic NC/Tnd mice housed in specific pathogen-free conditions induced kallikrein 5 and activated protease-activated receptor 2, resulting in thymic stromal lymphopoietin secretion and a cutaneous T-helper 2 allergic response. This was associated with increased transepidermal water loss and development of eczematous lesions in these specific pathogen-free NC/Tnd mice, which normally do not suffer from atopic dermatitis. Injection of recombinant thymic stromal lymphopoietin also induced scratching behavior in the specific pathogen-free NC/Tnd mice. Thymic stromal lymphopoietin production and dermatitis induced by alkalinization of the skin could be blocked by the protease-activated receptor 2 antagonist ENMD-1068. In contrast, weak acidification of eczematous skin in conventionally housed NC/Tnd mice reduced kallikrein 5 activity and ameliorated the dermatitis. Onset of the dermatitis was associated with increased epidermal filaggrin expression and impaired activity of the sodium/hydrogen exchanger 1, a known regulator of skin pH. We conclude that alterations in skin pH directly modulate kallikrein 5 activity leading to skin barrier dysfunction, itch, and dermatitis via the protease-activated receptor 2-thymic stromal lymphopoietin pathway.

A point mutation in the extracellular domain of KIT promotes tumorigenesis of mast cells via ligand-independent auto-dimerization.

Mutations in the juxtamembrane and tyrosine kinase domains of the KIT receptor have been implicated in several cancers and are known to promote tumorigenesis. However, the pathophysiological manifestations of mutations in the extracellular domain remain unknown. In this study, we examined the impact of a mutation in the extracellular domain of KIT on mast cell tumorigenesis. A KIT mutant with an Asn508Ile variation (N508I) in the extracellular domain derived from a canine mast cell tumor was introduced into IC-2 cells. The IC-2(N508I) cells proliferated in a cytokine-independent manner and showed KIT auto-phosphorylation. Subcutaneous injection of IC-2(N508I) cells into the dorsal area of immunodeficient BALB/c-nu/nu mice resulted in the formation of solid tumors, but tumor progression was abrogated by treatment with a tyrosine kinase inhibitor (STI571). In addition, the N508I mutant KIT protein dimerized in the absence of the natural ligand, stem cell factor. Structure modeling indicates that the increased hydrophobicity of the mutant led to the stabilization of KIT dimers. These results suggest that this extracellular domain mutation confers a ligand-independent tumorigenic phenotype to mast cells by KIT auto-dimerization that is STI571-sensitive. This is the first report demonstrating the tumorigenic potential of a mutation in the extracellular domain of KIT.