Involvement Of Mast Cells Research Articles

Obesity promotes prolonged ovalbumin-induced airway inflammation modulating T helper type 1 (Th1), Th2 and Th17 immune responses in BALB/c mice

Clinical and epidemiological studies indicate that obesity affects the development and phenotype of asthma by inducing inflammatory mechanisms in addition to eosinophilic inflammation. The aim of this study was to assess the effect of obesity on allergic airway inflammation and T helper type 2 (Th2) immune responses using an experimental model of asthma in BALB/c mice. Mice fed a high-fat diet (HFD) for 10 weeks were sensitized and challenged with ovalbumin (OVA), and analyses were performed at 24 and 48 h after the last OVA challenge. Obesity induced an increase of inducible nitric oxide synthase (iNOS)-expressing macrophages and neutrophils which peaked at 48 h after the last OVA challenge, and was associated with higher levels of interleukin (IL)-4, IL-9, IL-17A, leptin and interferon (IFN)-γ in the lungs. Higher goblet cell hyperplasia was associated with elevated mast cell influx into the lungs and trachea in the obese allergic mice. In contrast, early eosinophil influx and lower levels of IL-25, thymic stromal lymphopoietin (TSLP), CCL11 and OVA-specific immunoglobulin (IgE) were observed in the obese allergic mice in comparison to non-obese allergic mice. Moreover, obese mice showed higher numbers of mast cells regardless of OVA challenge. These results indicate that obesity affects allergic airway inflammation through mechanisms involving mast cell influx and the release of TSLP and IL-25, which favoured a delayed immune response with an exacerbated Th1, Th2 and Th17 profile. In this scenario, an intense mixed inflammatory granulocyte influx, classically activated macrophage accumulation and intense mucus production may contribute to a refractory therapeutic response and exacerbate asthma severity.

Acute granulocyte macrophage-colony stimulating factor treatment modulates neuroinflammatory processes and promotes tactile recovery after spinal cord injury

Neuroinflammation is known to play a key role in the prognosis of functional recovery after spinal cord injury (SCI). The involvement of microglial and mast cells in early and late stages of inflammation has been receiving increasing attention. This study was aimed at determining the influence of a pro-inflammatory cytokine, the granulocyte macrophage-colony stimulating factor (GM-CSF), on microglia and mast cell activation, glial scar formation and functional recovery following SCI. Rats were randomly injected with saline or GM-CSF one hour after a C4–C5 medio-lateral hemisection. To assess functional impairment and recovery, the rats were subjected to sensorimotor tasks for one month. Then, responses evoked by forepaw stimulation in the primary somatosensory cortex were recorded. We also quantified the changes in GM-CSF, IL-1β, IL-6 and BDNF levels, the gliosis and lesion volume as well as microglial and mast cell density, and mast cell surface. Our findings show that GM-CSF promotes cortical reactivation and recovery of tactile abilities, whereas it does not influence motor performances. A transient decrease in pro-inflammatory cytokines after GM-CSF treatment was also observed, whereas the endogenous GM-CSF level was unchanged. While the beneficial role of GM-CSF in reducing glial scar is confirmed, our findings reveal that neuroinflammatory events mediated by microglial and mast cells as well as the alteration of IL-1β and IL-6 levels are paralleled with an improvement in tactile recovery. These mechanisms could limit the duration and intensity of homeostatic imbalance and promote the plasticity of spared tissues.

Pressure overload leads to an increased accumulation and activity of mast cells in the right ventricle.

Right ventricular (RV) remodeling represents a complex set of functional and structural adaptations in response to chronic pressure or volume overload due to various inborn defects or acquired diseases and is an important determinant of patient outcome. However, the underlying molecular mechanisms remain elusive. We investigated the time course of structural and functional changes in the RV in the murine model of pressure overload‐induced RV hypertrophy in C57Bl/6J mice. Using magnetic resonance imaging, we assessed the changes of RV structure and function at different time points for a period of 21 days. Pressure overload led to significant dilatation, cellular and chamber hypertrophy, myocardial fibrosis, and functional impairment of the RV. Progressive remodeling of the RV after pulmonary artery banding (PAB) in mice was associated with upregulation of myocardial gene markers of hypertrophy and fibrosis. Furthermore, remodeling of the RV was associated with accumulation and activation of mast cells in the RV tissue of PAB mice. Our data suggest possible involvement of mast cells in the RV remodeling process in response to pressure overload. Mast cells may thus represent an interesting target for the development of new therapeutic approaches directed specifically at the RV.

The Innate Immune Response in Myocardial Infarction, Repair, and Regeneration.

Following myocardial infarction (MI), resident innate immune cells such as macrophages, innate lymphoid cells, and mast cells rapidly coordinate their function to contain inflammation by removing dying cells and promoting cardiomyocyte replenishment. To sustain local tissue repair functions, hematopoietic progenitors are mobilized from the bone marrow to the spleen to generate subsequent myeloid cells such as monocytes and neutrophils, which are rapidly recruited at the site of MI. A finely tuned balance between local adaptation and recruitment controls the overall outcome of the cardiac tissue regeneration versus repair and scar formation.In this chapter, the (potential) roles of the innate immune system residing in the heart are discussed in the context of recent findings about macrophage ontogeny and their homeostasis with circulating monocytes during cardiac tissue growth and after myocardial infarction. Their interactions with other members of the innate immune system are also discussed with a particular emphasis on the potential involvement of mast cells and innate lymphoid cells during MI, largely underestimated until recently. Understanding the development and the functions of the different protagonists responding to MI as well as their potential cross talk could help design new strategies for regenerative medicine intervention.

The role of mast cells in oral squamous cell carcinoma.

The mast cells are initial effective lineage in both humoral and adaptive immunity. They are ubiquitous in skin, mucosa, and in function. They contain biologically essential and dynamic mediators in healthy and harmful conditions of tissue. Mast cell malfunctioning could be attributed to various chronic allergic diseases. Considerately, emerging evidence of mast cell involvement in various cancers shows them to have both positive and negative roles in tumour growth. It mostly indulges in tumour progression and metastasis via angiogenesis, extracellular matrix degradation, and mitogenic activity in the tumour microenvironment. The current paper reviewed research papers on mast cells in oral squamous cell carcinoma through the PubMed database from 1980 to the present date. The present paper is an attempt to summarise the research reports on the role of mast cells in oral squamous cell carcinoma. Further to this note, this paper also outlines the role of mast cells in normal physiological processes and tumour biology.

Clonal Evolution Revealed By Exome Sequencing in a Case of Primary Myelofibrosis Associated with Subsequent Development of Aggressive Systemic Mastocytosis/Mast Cell Leukemia

A 77 year-old man initially presented in July 2013 with anemia, splenomegaly, and constitutional symptoms. A bone marrow biopsy revealed a hypercellular marrow with megakaryocytic hyperplasia and atypia and mild reticulin fibrosis, consistent with a diagnosis of primary myelofibrosis (PMF). Cytogenetics revealed a normal karyotype. JAK2 V617F testing was negative. Initiation of treatment with the JAK inhibitor ruxolitinib led to marked symptomatic improvement. The patient was then enrolled in a Phase 2 study with the anti-lysyl oxidase-like-2 (LOXL2) monoclonal antibody simtuzumab, administered via IV infusion every two weeks (while continuing ruxolitinib). He tolerated the simtuzumab infusions well initially, but with the 11th and 12th infusions experienced rigors, hypotension, and hypoxia. This occurred ~8 months after his initial PMF diagnosis. A repeat bone marrow biopsy revealed large aggregates of mast cells comprising 30-40% of the marrow cellularity (with 16% mast cells enumerated on the aspirate). A subset of the mast cells exhibited spindled morphology, and CD25 co-expression was demonstrated by flow cytometry in a subset of CD117-positive cells. Testing for the KITD816V mutation was positive. Tryptase levels were significantly elevated (375 ng/mL). These findings were consistent with a diagnosis of aggressive systemic mastocytosis with an associated hematologic non-mast cell lineage disorder (ASM-AHNMD).Compassionate-use approval for the KIT inhibitor midostaurin was obtained, and treatment with midostaurin (in addition to continuation of ruxolitinib) was initiated. The patient initially reported symptomatic improvement with midostaurin treatment, but after several months his symptoms began to worsen, with a corresponding increase in tryptase (875 ng/mL). A repeat bone marrow biopsy revealed overt evolution to mast cell leukemia (MCL) with > 90% mast cell involvement. Based on the presence of an IDH2mutation identified on a clinical next-generation sequencing assay, the patient was evaluated for a clinical trial with the mutant IDH2 inhibitor AG-221. Unfortunately, the patient decompensated and expired before he could enroll in the study.To identify contributing driver mutations and to delineate clonal hierarchy associated with disease initiation and progression in this unique case of PMF with concomitant ASM, exome sequencing was performed on serial samples obtained at the following disease stages:PMF diagnosis (pre-ruxolitinib) (Day 0)PMF on ruxolitinib (before ASM diagnosis) (Day 181)ASM diagnosis (post-anti-LOXL2 antibody, pre-midostaurin) (Day 394)Progression to MCL (on midostaurin) (Day 519)Matched skin (normal) sampleLikely driver mutations in IDH2 and SRSF2 were identified at ~40-50% variant allele frequency (VAF) in all samples and were therefore likely present in the founding clone. The KIT D816V mutation was found at 23% VAF at Day 0, then ~40% VAF in all other samples, suggesting it was present in a daughter subclone of the IDH2/SRSF2-containing clone that became dominant over time with disease progression. These findings also suggest that targeting KIT with midostaurin would be unlikely to eradicate the founding clone. Rather, selective targeting of IDH2 and/or SRSF2 could potentially ameliorate both diseases (PMF and ASM/MCL).To provide pre-clinical evidence of the potential utility of targeting IDH2, peripheral blood mononuclear cells obtained at the time of ASM diagnosis were plated in liquid culture in the presence or absence of the mutant IDH2 inhibitor AGI-6780. After 14 days in culture, the differentiation status of the cultured cells was examined by mass cytometry (CyTOF). Treatment with AGI-6780 resulted in a marked enhancement of myeloid differentiation (denoted by CD15 and CD66b expression) along with a corresponding decrease in CD34+ progenitor cells. These effects were not seen in cells cultured in the absence of AGI-6780. These results are consistent with prior studies in acute myeloid leukemia indicating that the beneficial effects of mutant IDH2 inhibition are likely related to inducing differentiation of primitive cells. In summary, this study highlights the capacity of serial genomic analysis to define the clonal architecture that drives disease initiation and evolution, and to distinguish founding vs subclonal mutations to identify the most promising targets for therapeutic intervention. DisclosuresOh:Janssen: Research Funding; CTI: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Disodium cromoglycate inhibits asthma-like features induced by sphingosine-1-phosphate

Compelling evidence suggests the involvement of sphingosine-1-phosphate (S1P) in the pathogenesis of asthma. The systemic administration of S1P causes asthma like features in the mouse involving mast cells. In this study we investigated whether disodium cromoglycate (DSCG), administered as a preventative treatment as in human therapy, could affect S1P effects on airways. BALB/c mice, treated with DSCG, received subcutaneous administration of S1P. Bronchi and pulmonary tissues were collected and functional, molecular and cellular studies were performed. DSCG inhibited S1P-induced airway hyper-reactivity as well as pulmonary inflammation. DSCG decreased the recruitment of solely mast cells and B cells in the lung. IgE serum levels, prostaglandin D2, mucus production and IL-13 were also reduced when mice were pretreated with DSCG. S1P induced pulmonary expression of CD23 on T and B cells, that was reversed by DSCG. Conversely, S1P failed to upregulate CD23 in mast cell-deficient Kit W−sh/W−sh mice. In conclusion we have shown that DSCG inhibits S1P-induced asthma like features in the mouse. This beneficial effect is due to a regulatory action on mast cell activity, and in turn to an inhibition of IgE-dependent T and B cells responses.

Systemic Mastocytosis Complicated by Non-cirrhotic Portal Hypertension and Variceal Bleeding

Introduction: Systemic mastocytosis is characterized by mast cell hyperplasia with infiltration and accumulation in at least one extracutaneous organ. While the most common site of extracutaneous involvement is the bone marrow, hepatic involvement may result in hepatic fibrosis and pre-sinusoidal, non-cirrhotic portal hypertension. Case: An 82 year-old woman with a history of systemic mastocytosis, confirmed by bone marrow biopsy three years prior, on chronic prednisone presented with maroon-colored stool and bright red blood per rectum. She reported no previous episodes of gastrointestinal bleeding. On arrival, the patient was hemodynamically stable. Exam disclosed an elderly woman with anicteric sclera, benign abdominal exam with no organomegaly, and external hemorrhoids with gross maroon-colored stool on digital rectal exam. Initial laboratory data was notable for Hgb 6.8 mg/dL, albumin 2.9 g/dL, platelets 76, creatinine 0.4 mg/dL, INR 1.22, and unremarkable liver function tests aside from a chronically elevated alkaline phosphatase of 249 U/L. Endoscopy demonstrated three columns of large esophageal varices (EV) at 28 cm with extension to gastroesophageal junction and red wale sign, moderate portal hypertensive gastropathy in the gastric cardia, and no ulcerations [Figure]. Five bands were placed with obliteration of the EV, nadolol was started for secondary prophylaxis, and the patient had no further episodes of bleeding. Abdominal ultrasound demonstrated normal appearing liver with patent hepatic and portal veins. Alternative testing to evaluate the etiology of portal hypertension was unremarkable. No liver biopsy was performed as the patient was already on prednisone for treatment of mastocytosis and was high-risk for bleeding.Figure 1Discussion: While the exact mechanism is unknown, it is postulated that non-cirrhotic portal hypertension may develop as a result of infiltration of inflammatory mast cells within the portal vein and obstruction of the sinusoids, thus resulting in increased portal pressures and pre-sinusoidal obstruction. Given the involvement of mast cells, the addition of histamine and leukotriene receptor antagonists is an important addition to traditional management. Overall, no study has identified what percent of patients with systemic mastocytosis develop portal hypertension. Ultimately, this case reinforces the importance of and need for appropriate portal hypertensive screening in patients with systemic mastocytosis.

Systemic Mastocytosis With Pulmonary Involvement

SESSION TITLE: Fellow Case Report Slide: Pulmonary Critical Care Disorders: Think Twice SESSION TYPE: Affiliate Case Report Slide PRESENTED ON: Sunday, October 23, 2016 at 10:45 AM - 12:00 PM INTRODUCTION: Mastocytosis is a rare disorder that involves mast cell infiltration in a range of organs. Pulmonary involvement is an even rarer entity. Here we present a case of a patient with systemic mastocytosis with asymptomatic pulmonary involvement. CASE PRESENTATION: The patient is a 68 year old male who was referred to primary clinic to establish care. He recently presented to the emergency room for abdominal pain of seven months duration. There he was diagnosed with gallstones and an inguinal hernia and discharged with primary care followup. The only other complaint the patient had was persistent pruritus for over one year. On review of systems the patient was noted to have weight loss. He denied any cough or shortness of breath. On exam the patient was cachectic with numerous skin excoriations from scratching. He had mild right upper quadrant tenderness, hepatomegaly, and a reducible inguinal hernia. Labs were notable for an alkaline phosphatase of 652 IU/L and a leukocytosis of 11.8 cells per mL with 29% eosinophils. Serum tryptase was significantly elevated at 130 ng/mL. Abdominal ultrasound demonstrated hepatomegaly with coarse lobulated surface suggestive of chronic liver disease. A chest X-ray obtained during his emergency room visit was notable for diffuse reticular opacities. Chest CT showed pulmonary nodules and hilar lymphadenopathy. Liver biopsy and EBUS were performed with pathology consistent with systemic mastocytosis. DISCUSSION: Systemic mastocysotosis is a rare disease and involvement of the skeletal muscle, gastrointestinal tract, and lymph nodes is common. Pulmonary involvement is less common and may occur in less than 20% of patients with systemic mastocytosis. Symptoms can include cough, dyspnea, and asthma like symptoms. Findings on chest radiograph include interstitial fibrosis and pulmonary nodules. CT findings include nodular and reticular opacities as well as mediastinal lymph node enlargement. CONCLUSIONS: Pulmonary involvement is a rare manifestation of systemic mastocytosis. The disease can present with a wide range of findings on chest radiograph and CT. Symptoms can vary between being asymptomatic to having mild asthma like symptoms. Reference #1: Avila N. A. et al. 1996. Pulmonary and Ovarian Manifestations of Systemic Mastocytosis. AJR; 166: 969-970. Reference #2: Kelly A. M. et al. 2004. HRCT Appearance of Systemic Mastocytosis Involving the Lungs. J Thoracic Imaging; 19: 52-55. Reference #3: Schmidt M. et al. 2000. Pulmonary manifestation of systemic mast cell disease. Eur Respir J; 15: 623 - 625. DISCLOSURE: The following authors have nothing to disclose: Ray Pillai, Darren Maehara, Nishay Chitkara No Product/Research Disclosure Information

Involvement of mast cells and histamine in edema induced in mice by Scolopendra viridicornis centipede venom

Bites caused by Scolopendra viridicornis centipede are mainly characterized by burning pain, paresthesia and edema. On this regard, the aim of this work was to study the involvement of mast cells and histamine in edema induced by Scolopendra viridicornis (Sv) centipede venom. The edema was analyzed on mice paws. The mice were pretreated with cromolyn (mast cell degranulation inhibitor) and antagonists of histamine receptors, such as promethazine (H1R), cimetidine (H2R) and thioperamide (H3/H4R). The analyses were carried out at different times after the injection of Sv venom (15 μg) or PBS in the footpad of mice. Our results showed a significant inhibition of the edema induced by Sv venom injection in mice previously treated: cromolyn (38–91%), promethazine (50–59%) and thioperamide (around 30%). The treatment with cimetidine did not alter the edema induced by Sv venom. Histopathological analysis showed that Sv venom injection (15 μg) induced edema, leukocyte recruitment and mast cells degranulation, when compared with the PBS-injected mice. Direct effects of the Sv venom on mast cells were studied in PT-18 line (mouse mast cell) and RBL-2H3 cells (rat mast cells). The data showed that higher doses (3.8 and 7.5 μg) of Sv venom were cytotoxic for both cell lineages and induced morphological changes. However, lower doses of the venom induced degranulation of both mast cell lines, as well as the secretion of MCP-1, IL-6 and IL-1β. The production of PGD2 was only observed in the RBL-2H3 line incubated with Sv venom. Taking our results together, we demonstrated that upon Sv venom exposure, mast cells and histamine are crucial for the establishment of the local inflammatory reaction.

Dendritic and mast cell involvement in the inflammatory response to primary malignant bone tumours.

BackgroundA chronic inflammatory cell infiltrate is commonly seen in response to primary malignant tumours of bone. This is known to contain tumour-associated macrophages (TAMs) and lymphocytes; dendritic cells (DCs) and mast cells (MCs) have also been identified but whether these and other inflammatory cells are seen commonly in specific types of bone sarcoma is uncertain.MethodsIn this study we determined the nature of the inflammatory cell infiltrate in 56 primary bone sarcomas. Immunohistochemistry using monoclonal antibodies was employed to assess semiquantitatively CD45+ leukocyte infiltration and the extent of the DC, MC, TAM and T and B lymphocyte infiltrate.ResultsThe extent of the inflammatory infiltrate in individual sarcomas was very variable. A moderate or heavy leukocyte infiltrate was more commonly seen in conventional high-grade osteosarcoma, undifferentiated pleomorphic sarcoma and giant cell tumour of bone (GCTB) than in Ewing sarcoma, chordoma and chondrosarcoma. CD14+/CD68+ TAMs and CD3+ T lymphocytes were the major components of the inflammatory cell response but (DC-SIGN/CD11c+) DCs were also commonly noted when there was a significant TAM and T lymphocyte infiltrate. MCs were identified mainly at the periphery of sarcomas, including the osteolytic tumour-bone interface.DiscussionOur findings indicate that, although variable, some malignant bone tumours (e.g. osteosarcoma, GCTB) are more commonly associated with a pronounced inflammatory cell infiltrate than others (e.g. chondrosarcoma. Ewing sarcoma); the infiltrate is composed mainly of TAMs but includes a significant DC, T lymphocyte and MC infiltrate.ConclusionTumours that contain a heavy inflammatory cell response, which includes DCs, TAMs and T lymphocytes, may be more amenable to immunomodulatory therapy. MCs are present mainly at the tumour edge and are likely to contribute to osteolysis and tumour invasion.

Association of cardiac NT pro-β-type natriuretic peptide with metabolic and endothelial risk factors in young obese hypertensive patients: a perspective on the hypothalamic pituitary adrenal axis activation.

BackgroundIn practice, there is increasing recognition of the importance of hypothalamic pituitary adrenal axis in the cardiovascular disease progression. The association of brain natriuretic peptide with obesity and characteristics of the metabolic syndrome in adults and aged patients is well established, but that in pediatrics needs thorough elucidation.AimThe aim of this study was to assess the association of hypothalamic pituitary adrenal axis mediators (cortisol and aldosterone) with plasma NT-pro β-type natriuretic peptide (NT-proBNP) levels on metabolic, immune-inflammatory and endothelial markers in young obese pediatric patients.MethodsThis is achieved by recruitment of 60 young (13–17 years) obese pediatric cohorts who are further subclassified according to their stage of hypertension; normotensive, prehypertensive and hypertensive patients.ResultsThe study showed significant differences in the metabolic parameters (glucose, insulin and HOMA-index) among the three obese young patient groups. Levels of cortisol and aldosterone, as well as NT-proBNP levels are positively associated with characteristics of the metabolic syndrome; blood pressure, BMI, HOMA index in all three obese groups. However, their association to the lipid profile was insignificant. These increases aligned harmonically with the assessed immune-inflammatory markers; CRP, TNF-α, and IL-23, as well as levels of sICAM, sVCAM and p-selectin, reflecting the involvement of mast cells and inflammatory effects on the vascular endothelium. ROC analysis revealed their beneficial addition as promising biomarkers for a better prognostic profile of hypertension-induced cardiovascular risk.ConclusionEarly detection of NT-proBNP, cortisol and aldosterone levels in pre-hypertension stage added to the immune-inflammatory mediators may improve the coronary risk assessment in young Egyptian patients.

Identification of Biological and Pharmaceutical Mast Cell‐ and Basophil‐Related Targets

Identification of Biological and Pharmaceutical Mast Cell‐ and Basophil‐Related Targets

Involvement of mast cells and microvessels density in reactive lesions of oral cavity: A comparative immunohistochemical study

In view of the similarity of clinicopathological features between reactive lesions of the oral cavity, the objective of the present study was to investigate the density of MCs (mast cells) and microvessels in a series of these lesions. Thirty-seven cases of reactive lesions including fibrous hyperplasia (FH, n=10), inflammatory fibrous hyperplasia (IFH, n=10), peripheral giant cell lesion (PGCL, n=10) and lobular capillary hemangioma (LCH, n=7) were investigated using immunohistochemistry for mast cell tryptase and CD34. For comparative purposes, central giant cell lesions (CGCL, n=5) were included. A higher MC density was observed in LCH (37.01), while CGCL exhibited the lowest density (n=8.14). There was a significant difference in MC density when all reactive lesions were compared to CGCL (p=0.001). The largest mean density of microvessels was observed in LCH (n=21.69). The smallest number was observed in CGCL (n=6.24). There was a significant difference in microvessel density when the reactive lesions were compared to CGCL (p=0.003). There was a significant and direct correlation between the density of MCs and microvessels only for IFH (p=0.048) and CGCL (p=0.005). A significant and direct correlation between the mean density of MCs and microvessels was observed when the reactive lesions were analyzed as a whole (p=0.005). Our results suggest that mast cells contribute to the connective tissue framework and angiogenic function, as well as the development, of reactive lesions of the oral cavity, including FH, IFH, LCH and PGCL.

Mammary tumor growth and metastasis are reduced in c-Kit mutant Sash mice.

Besides its well‐known function in allergic response, mast cell, one of the key immune cells present in tumor microenvironment, plays important roles in cancer progression. However, the functional role of mast cells in breast cancer development and metastasis is not well understood. To test the involvement of mast cells in breast cancer, we examined the effects of loss of mast cells on mammary tumor development by crossing the well‐known mast cell deficient mouse strain sash (KitW‐sh/W‐sh) with the mammary tumor transgenic mouse strain MMTV‐Polyoma Middle T antigen (PyMT). Although mammary tumor onset was not affected in the absence of mast cells, mammary growth and metastasis were reduced in PyMT/KitW‐sh/W‐sh mice compared with PyMT/wild‐type mice (WT). Histological and immunofluorescent analyses showed that tumors from PyMT/KitW‐sh/W‐sh mice showed largely differentiated morphology with reduced angiogenesis compared with MMTV‐PyMT/WT mice. Our results suggest that mast cells may promote breast cancer growth and metastasis. Agents that can block mast cells growth are potential new therapies to treat metastatic breast cancer.

ROCK1 via LIM kinase regulates growth, maturation and actin based functions in mast cells.

Understanding mast cell development is essential due to their critical role in regulating immunity and autoimmune diseases. Here, we show how Rho kinases (ROCK) regulate mast cell development and can function as therapeutic targets for treating allergic diseases. Rock1 deficiency results in delayed maturation of bone marrow derived mast cells (BMMCs) in response to IL-3 stimulation and reduced growth in response to stem cell factor (SCF) stimulation. Further, integrin-mediated adhesion and migration, and IgE-mediated degranulation are all impaired in Rock1-deficient BMMCs. To understand the mechanism behind altered mast cell development in Rock1−/− BMMCs, we analyzed the activation of ROCK and its downstream targets including LIM kinase (LIMK). We observed reduced activation of ROCK, LIMK, AKT and ERK1/2 in Rock1-deficient BMMCs in response to SCF stimulation. Further, loss of either Limk1 or Limk2 also demonstrated altered BMMC maturation and growth; combined deletion of both Limk1 and Limk2 resulted in further reduction in BMMC maturation and growth. In passive cutaneous anaphylaxis model, deficiency of Rock1 or treatment with ROCK inhibitor Fasudil protected mice against IgE-mediated challenge. Our results identify ROCK/LIMK pathway as a novel therapeutic target for treating allergic diseases involving mast cells.

Fish innate immunity against intestinal helminths.

Most individual fish in farmed and wild populations are infected with parasites. Upon dissection of fish, helminths from gut are often easily visible. Enteric helminths include several species of digeneans, cestodes, acanthocephalans and nematodes. Some insights into biology, morphology and histopathological effects of the main fish enteric helminths taxa will be described here. The immune system of fish, as that of other vertebrates, can be subdivided into specific and aspecific types, which in vivo act in concert with each other and indeed are interdependent in many ways. Beyond the small number of well-described models that exist, research focusing on innate immunity in fish against parasitic infections is lacking. Enteric helminths frequently cause inflammation of the digestive tract, resulting in a series of chemical and morphological changes in the affected tissues and inducing leukocyte migration to the site of infection. This review provides an overview on the aspecific defence mechanisms of fish intestine against helminths. Emphasis will be placed on the immune cellular response involving mast cells, neutrophils, macrophages, rodlet cells and mucous cells against enteric helminths. Given the relative importance of innate immunity in fish, and the magnitude of economic loss in aquaculture as a consequence of disease, this area deserves considerable attention and support.

Involvement of Mast Cells in α7 Nicotinic Receptor Agonist Exacerbation of Freund's Complete Adjuvant-Induced Monoarthritis in Mice.

Activation of antiinflammatory cholinergic (vagal) pathways can reduce inflammation, and in vitro studies support a pivotal role of α7 nicotinic acetylcholine receptors (α7-nAChR), macrophages, and T cells in these events. The aim of this study was to assess α7-nAChR agonists as an antiinflammatory treatment for Freund's complete adjuvant (CFA)-induced monoarthritis. Arthritis was induced by intraarticular injection of CFA unilaterally into the knee joints of mice. Animals were treated with α7-nAChR agonists (AR-R17779 or A844606), with or without antagonists (COG133 or methyllycaconitine), and joint inflammation and pain were assessed. Experiments were repeated in c-Kit(W-sh) mast cell-deficient mice, and the effects of an α7-nAChR agonist on mast cell proliferation, migration, and activation by lipopolysaccharide (LPS) were tested. Treatment with α7-nAChR agonists significantly exacerbated CFA-induced arthritis and pain, as gauged by all indices of assessment, the specificity of which was confirmed by coadministration of an nAChR antagonist that attenuated the increase in disease severity. Toluidine blue-positive mast cells were increased in the joint capsule of CFA plus AR-R17779-treated mice, and AR-R17779 enhanced LPS-induced TNF proliferation and migration of a human mast cell line. The AR-R17779-driven increase in severity of CFA-induced arthritis was significantly reduced in mast cell-deficient mice. Using CFA to elicit a local inflammatory response, we found that pharmacologic activation of α7-nAChR exacerbated joint inflammation and pain, in part via mast cells, which illustrates the organ- and disease-specific nature of regulatory neuroimmune mechanisms. Thus, α7-nAChR activation may not be uniformly antiinflammatory in all types of inflammatory joint disease.

Involvement of mast cells and proteinase-activated receptor 2 in oxaliplatin-induced mechanical allodynia in mice

The chemotherapeutic agent oxaliplatin induces neuropathic pain, a dose-limiting side effect, but the underlying mechanisms are not fully understood. Here, we show the potential involvement of cutaneous mast cells in oxaliplatin-induced mechanical allodynia in mice. A single intraperitoneal injection of oxaliplatin induced mechanical allodynia, which peaked on day 10 after injection. Oxaliplatin-induced mechanical allodynia was almost completely prevented by congenital mast cell deficiency. The numbers of total and degranulated mast cells was significantly increased in the skin after oxaliplatin administration. Repetitive topical application of the mast cell stabilizer azelastine hydrochloride inhibited mechanical allodynia and the degranulation of mast cells without affecting the number of mast cells in oxaliplatin-treated mice. The serine protease inhibitor camostat mesilate and the proteinase-activated receptor 2 (PAR2) antagonist FSLLRY-NH2 significantly inhibited oxaliplatin-induced mechanical allodynia. However, it was not inhibited by the H1 histamine receptor antagonist terfenadine. Single oxaliplatin administration increased the activity of cutaneous serine proteases, which was attenuated by camostat and mast cell deficiency. Depletion of the capsaicin-sensitive primary afferents by neonatal capsaicin treatment almost completely prevented oxaliplatin-induced mechanical allodynia, the increase in the number of mast cells, and the activity of cutaneous serine proteases. These results suggest that serine protease(s) released from mast cells and PAR2 are involved in oxaliplatin-induced mechanical allodynia. Therefore, oxaliplatin may indirectly affect the functions of mast cells through its action on capsaicin-sensitive primary afferents.

Brain Fires in Autism Spectrum Disorders

Autism spectrum disorders (ASD) is characterized by social and communicative deficits, severe anxiety, and stereotypic movements. Despite affecting as many as 1 in 45 US children in the USA, the pathogenesis of ASD is still unknown. Recent epidemiological studies indicated a strong statistical correlation between risk for maternal / infant atopic diseases and ASD suggesting the possible involvement and activation of mast cells (MC). These unique immune cells are located close to blood vessels in all tissues, including the thalamus and hypothalamus in the brain, which regulate emotions known to be dysfunctional in ASD. Moreover, MCs are stimulated by two brain peptides, corticotropin-releasing hormone (CRH) and neurotensin (NT), which we showed to be high in the blood of children with ASD. Stimulated MCs then secrete inflammatory molecules that activate brain microglia, which proliferate and “choke off” nerve communication. These inflammatory molecules are increased in the brain and serum of patients with ASD and also lead to disruption of the protective blood brain barrier (BBB), which is regulated by MCs, permitting the entry of circulating white blood cells and toxins contributing to brain. We further reported that the elevated blood levels of two inflammatory molecules, IL-6 and TNF, identify a subgroup of children with ASD, who benefit most from a promising treatment with the natural flavonoid luteolin that combats brain inflammation. Extinguishing inflammation (“Brain fires”) may be the best hope for curing ASD.