Phospholipase A2 induces acute kidney injury by complement mediated mitochondrial apoptosis via TNF-α/NF-κB signaling pathway.

OBJECTIVE: Acute kidney injury (AKI) is one of common complications of wasp/bee stings. Phospholipase A2 (PLA2) is a vital pathogenic composition of wasp/bee venom. We aimed to investigate the role of complement mediated mitochondrial apoptosis in PLA2 induced AKI. MATERIALS AND METHODS: PLA2 induced AKI model was established by injecting PLA2 into via tail vein on mice. The pathological changes and the microstructural changes of kidney, complement activation, inflammation and apoptosis were detected in vitro and in vivo respectively. RESULTS: The results showed that PLA2 induced AKI models were successfully established in vivo and vitro. Compared with control, serum creatinine and urea nitrogen levels were elevated. Complement system activation and mitochondrial damage were observed. Expressions of IL-6, TNF-α, cleaved caspase-3 and cleaved caspase-9, and Bax/Bcl-2 increased in PLA2 induced AKI models. TNF-α/NF-κB signaling pathway activation in AKI models. CONCLUSION: In the present study, PLA2 induced AKI model was first successfully established to our knowledge. The role of complement mediated mitochondrial apoptosis pathway in renal tubular epithelial cells in PLA2 induced AKI were verified in vitro and vivo.

COMMD8 changes expression during initial phase of wasp venom immunotherapy.

BACKGROUND: Hymenoptera venom allergy (HVA) is of great concern because of the possibility of anaphylaxis, which may be fatal. Venom immunotherapy (VIT) is the only disease-modifying treatment in HVA and, although efficient, its mechanism remains partially unknown. Gene expression analysis may be helpful for establishing a proper model of tolerance induction during the build-up phase of VIT. The present study aimed to analyze how the start of VIT changes the expression of 15 selected genes. METHODS: Forty-five patients starting VIT with a wasp venom allergy were enrolled. The diagnosis was established based on anaphylaxis history (third or fourth grade on the Mueller scale) and positive soluble immunoglobulin E and/or skin tests. Two blood collections were performed in the patient group: before and after 3 months of VIT. One sample was taken in the control group. Gene expression analysis was performed using a reverse transcriptase-polymerase chain reaction with microfluidic cards and normalized to the 18S housekeeping gene. RESULTS: Commd8 was the only gene that changed expression significantly after the start of VIT (p = 0.012). Its expression decreased towards the levels observed in the healthy controls. Twelve out of 15 genes (commd8, cldn1, cngb3, fads1, hes6, hla-drb5, htr3b, prlr, slc16a4, snx33, socs3 and twist2) revealed a significantly different expression compared to the healthy controls. CONCLUSIONS: The present study shows that commd8 changes significantly its expression during initial phase of VIT. This gene might be a candidate for VIT biomarker in future studies.

Functional Profile of Antigen Specific CD4+ T Cells in the Immune Response to Phospholipase A1 Allergen from Polybia paulista Venom.

Insect venom can cause systemic allergic reactions, including anaphylaxis. Improvements in diagnosis and venom immunotherapy (VIT) are based on a better understanding of an immunological response triggered by venom allergens. Previously, we demonstrated that the recombinant phospholipase A1 (rPoly p 1) from Polybia paulista wasp venom induces specific IgE and IgG antibodies in sensitized mice, which recognized the native allergen. Here, we addressed the T cell immune response of rPoly p 1-sensitized BALB/c mice. Cultures of splenocytes were stimulated with Polybia paulista venom extract and the proliferation of CD8+ and CD4+ T cells and the frequency of T regulatory cells (Tregs) populations were assessed by flow cytometry. Cytokines were quantified in cell culture supernatants in ELISA assays. The in vitro stimulation of T cells from sensitized mice induces a significant proliferation of CD4+ T cells, but not of CD8+ T cells. The cytokine pattern showed a high concentration of IFN-γ and IL-6, and no significant differences to IL-4, IL-1ß and TGF-ß1 production. In addition, the rPoly p 1 group showed a pronounced expansion of CD4+CD25+FoxP3+ and CD4+CD25-FoxP3+ Tregs. rPoly p 1 sensitization induces a Th1/Treg profile in CD4+ T cell subset, suggesting its potential use in wasp venom immunotherapy.

A case of nodal marginal zone lymphoma with hypersensitivity to mosquito bites as initial symptom.

Hypersensitivity to mosquito bites (HMB) refers to skin reactions such as bullae and necrosis, which occurs after being bitten by mosquitoes and can present with multiple systemic reactions such as fever, lymphadenopathy, hepatosplenomegaly simultaneously or subsequently. A 48-year-old male patient presented with recurrent erythema, nodules, papules, vesicles and bullae over upper body and bilateral limbs with itching over the sites of mosquito bite for more than 1 year with low-grade fever and superficial lymph nodes enlargement. The patient's symptoms failed to improve from conventional anti allergic treatment although skin biopsy showed changes of HMB reaction. Subsequently, the lymph node was biopsied and was reported to be nodal marginal zone lymphoma (NMZL), and then the patient was eventually diagnosed with nodal marginal zone lymphoma with HMB. To date only one case of nodal marginal zone lymphoma with HMB has been reported from Korea, and this is the first case to be reported in China.

Immunologic difference between hypersensitivity to mosquito bite and hemophagocytic lymphohistiocytosis associated with Epstein-Barr virus infection.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening, virus-triggered immune disease. Hypersensitivity to mosquito bite (HMB), a presentation of Chronic Active Epstein-Barr Virus infection (CAEBV), may progress to HLH. This study aimed to investigate the immunologic difference between the HMB episodes and the HLH episodes associated with EBV infection. Immunologic changes of immunoglobulins, lymphocyte subsets, cytotoxicity, intracellular perforin and granzyme expressions, EBV virus load and known candidate genes for hereditary HLH were evaluated and compared. In 12 HLH episodes (12 patients) and 14 HMB episodes (4 patients), there were both decreased percentages of CD4+ and CD8+ and increased memory CD4+ and activated (CD2+HLADR+) lymphocytes. In contrast to HMB episodes that had higher IgE levels and EBV virus load predominantly in NK cells, those HLH episodes with virus load predominantly in CD3+ lymphocyte had decreased perforin expression and cytotoxicity that were recovered in the convalescence period. However, there was neither significant difference of total virus load in these episodes nor candidate genetic mutations responsible for hereditary HLH. In conclusion, decreased perforin expression in the HLH episodes with predominant-CD3+ EBV virus load is distinct from those HMB episodes with predominant-NK EBV virus load. Whether the presence of non-elevated memory CD4+ cells or activated lymphocytes (CD2+HLADR+) increases the mortality rate in the HLH episodes remains to be further warranted through larger-scale studies.

The origin of intraspecific variation of virulence in an eukaryotic immune suppressive parasite.

Occurrence of intraspecific variation in parasite virulence, a prerequisite for coevolution of hosts and parasites, has largely been reported. However, surprisingly little is known of the molecular bases of this variation in eukaryotic parasites, with the exception of the antigenic variation used by immune-evading parasites of mammals. The present work aims to address this question in immune suppressive eukaryotic parasites. In Leptopilina boulardi, a parasitic wasp of Drosophila melanogaster, well-defined virulent and avirulent strains have been characterized. The success of virulent females is due to a major immune suppressive factor, LbGAP, a RacGAP protein present in the venom and injected into the host at oviposition. Here, we show that an homologous protein, named LbGAPy, is present in the venom of the avirulent strain. We then question whether the difference in virulence between strains originates from qualitative or quantitative differences in LbGAP and LbGAPy proteins. Results show that the recombinant LbGAPy protein has an in vitro GAP activity equivalent to that of recombinant LbGAP and similarly targets Drosophila Rac1 and Rac2 GTPases. In contrast, a much higher level of both mRNA and protein is found in venom-producing tissues of virulent parasitoids. The F1 offspring between virulent and avirulent strains show an intermediate level of LbGAP in their venom but a full success of parasitism. Interestingly, they express almost exclusively the virulent LbGAP allele in venom-producing tissues. Altogether, our results demonstrate that the major virulence factor in the wasp L. boulardi differs only quantitatively between virulent and avirulent strains, and suggest the existence of a threshold effect of this molecule on parasitoid virulence. We propose that regulation of gene expression might be a major mechanism at the origin of intraspecific variation of virulence in immune suppressive eukaryotic parasites. Understanding this variation would improve our knowledge of the mechanisms of transcriptional evolution currently under active investigation.

Profiling the proteome of the venom from the social wasp Polybia paulista: a clue to understand the envenoming mechanism.

The study reported here is a classical bottom-up proteomic approach where proteins from wasp venom were extracted and separated by 2-DE; the individual protein spots were proteolytically digested and subsequently identified by using tandem mass spectrometry and database query with the protein search engine MASCOT. Eighty-four venom proteins belonging to 12 different molecular functions were identified. These proteins were classified into three groups; the first is constituted of typical venom proteins: antigens-5, hyaluronidases, phospholipases, heat shock proteins, metalloproteinases, metalloproteinase-desintegrin like proteins, serine proteinases, proteinase inhibitors, vascular endothelial growth factor-related protein, arginine kinases, Sol i-II and -II like proteins, alpha-glucosidase, and superoxide dismutases. The second contained proteins structurally related to the muscles that involves the venom reservoir. The third group, associated with the housekeeping of cells from venom glands, was composed of enzymes, membrane proteins of different types, and transcriptional factors. The composition of P. paulista venom permits us to hypothesize about a general envenoming mechanism based on five actions: (i) diffusion of venom through the tissues and to the blood, (ii) tissue, (iii) hemolysis, (iv) inflammation, and (v) allergy-played by antigen-5, PLA1, hyaluronidase, HSP 60, HSP 90, and arginine kinases.

Detection of honeybee venom in envenomed tissues by direct MALDI MSI.

A new analytical approach using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) for the study of honeybee venom is shown. In vitro and in vivo models simulating the bee sting have been developed using live honeybees and, as the envenomation sites, pig ears and rat legs; MALDI MSI has been used to map, over time, the diffusion and distribution of three venom allergens (Api m 1, Api m 4, and Api m 6) and two venom toxins (apamine and mast cell degranulating peptide). In conjunction with other classical biochemical techniques and high resolution mass spectrometry (HRMS), structural data have been obtained that contribute to current understanding of honeybee venom composition. Initial data have also been obtained demonstrating the feasibility of mapping the organism's response to the sting. The opportunity to monitor venom diffusion and the organism's response at the same time might open new pathways for in vivo preclinical studies in designing and testing new venom immunotherapy (VIT).

Kallikrein-kinin system activation by Lonomia obliqua caterpillar bristles: involvement in edema and hypotension responses to envenomation.

Lonomia obliqua envenomation induces an intense burning sensation at the site of contact and severe hemorrhage followed by edema and hypotension, and after few days death can occur usually due to acute renal failure. In order to understand more about the envenomation syndrome, the present study investigates the role played by kallikrein-kinin system (KKS) in edematogenic and hypotensive responses to the envenomation by L. obliqua. The incubation of L. obliqua caterpillar bristles extract (LOCBE) with plasma results in kallikrein activation, measured by cromogenic assay using the kallikrein synthetic substrate S-2302 (H-D-Pro-Phe-Arg-pNA). It was also showed that LOCBE was able to release kinins from low-molecular weight kininogen (LMWK). Moreover, it was demonstrated that previous administration of a kallikrein inhibitor (aprotinin) or bradykinin B2 receptor antagonist (HOE-140) significantly reduces the edema and hypotension in response to LOCBE, using mouse paw edema bioassay and mean arterial blood pressure analysis, respectively. The results demonstrate a direct involvement of the KKS in the edema formation and in the fall of arterial pressure that occur in the L. obliqua envenomation syndrome.

Insect bite-induced hypersensitivity and the SCRATCH principles: a new approach to papular urticaria.

Insect bites and the associated hypersensitivity reactions known as papular urticaria account for a significant number of all referrals from pediatricians and dermatologists to our pediatric dermatology clinic. Unfortunately, children affected by these eruptions are frequently misdiagnosed and often subject to expensive evaluations including invasive and unnecessary procedures. Here we review the course of 4 children with the typical physical findings and natural history of these reactions. On the basis of our clinical findings and experience with this patient population, we propose a set of principles (termed "SCRATCH") as clinical features to aid clinicians in making an early and accurate clinical diagnosis. We conclude that a more appropriate term for future study and diagnosis of this entity is insect bite-induced hypersensitivity.

Protein electrophoresis in cranes with presumed insect bite.

BACKGROUND: Serum protein electrophoresis (SPE) has emerged as a potentially valuable diagnostic tool in avian medicine; yet, there is limited information regarding SPE in cranes. Since 2000, 20 cases of unilateral periocular or facial soft tissue swelling, blepharitis, feather loss, and ocular or nasal discharge attributed to insect bite hypersensitivity were observed in cranes from a captive breeding center. SPE may be useful for evaluating these lesions. OBJECTIVE: The aim of this study was to characterize the inflammatory response in cranes with hypersensitivity reactions using SPE. METHODS: Serum samples from 7 cranes diagnosed with hypersensitivity reactions were submitted to a diagnostic laboratory for agarose gel electrophoresis. Results were compared to those in control serum samples obtained from the same cranes during routine physical examination, when they were clinically healthy. RESULTS: Total protein and a- and g-globulin concentrations were significantly increased and albumin/globulin ratios were significantly decreased in serum samples from cranes with hypersensitivity lesions compared with control samples. CONCLUSIONS: Using SPE, we documented changes in protein fraction concentrations in cranes with clinical signs of hypersensitivity. The increase in alpha- and gamma-globulin concentrations suggested inflammation and antigenic stimulation, consistent with a Type I hypersensitivity reaction.

Effects of feeding Spodoptera littoralis on lima bean leaves. I. Membrane potentials, intracellular calcium variations, oral secretions, and regurgitate components.

Membrane potentials (V(m)) and intracellular calcium variations were studied in Lima bean (Phaseolus lunatus) leaves when the Mediterranean climbing cutworm (Spodoptera littoralis) was attacking the plants. In addition to the effect of the feeding insect the impact of several N-acyl Glns (volicitin, N-palmitoyl-Gln, N-linolenoyl-Gln) from the larval oral secretion was studied. The results showed that the early events upon herbivore attack were: a) a strong V(m) depolarization at the bite zone and an isotropic wave of V(m) depolarization spreading throughout the entire attacked leaf; b) a V(m) depolarization observed for the regurgitant but not with volicitin [N-(17-hydroxy-linolenoyl)-Gln] alone; c) an enhanced influx of Ca(2+) at the very edge of the bite, which is halved, if the Ca(2+) channel blocker Verapamil is used. Furthermore, the dose-dependence effects of N-acyl Gln conjugates-triggered influx of Ca(2+) studied in transgenic aequorin-expressing soybean (Glycine max) cells, showed: a) a concentration-dependent influx of Ca(2+); b) a configuration-independent effect concerning the stereochemistry of the amino acid moiety; c) a slightly reduced influx of Ca(2+) after modification of the fatty acid backbone by functionalization with oxygen and; d) a comparable effect with the detergent SDS. Finally, the herbivore wounding causes a response in the plant cells that cannot be mimicked by mechanical wounding. The involvement of Ca(2+) in signaling after herbivore wounding is discussed.

CD30-positive atypical lymphoid cells in common non-neoplastic cutaneous infiltrates rich in neutrophils and eosinophils.

CD30-positive cells characterize lymphomatoid papulosis and anaplastic large cell lymphoma but can also be found in nonneoplastic skin disorders. Purportedly, CD30 is useful in the differential diagnosis between insect bites and lymphomatoid papulosis. Recently, a subtype of neutrophil-rich CD30-positive anaplastic large cell lymphoma has been described, which may enter the differential diagnosis of cutaneous neutrophil-rich inflammatory infiltrates. We studied atypical CD30-positive lymphoid cells in five eosinophil-rich and 23 neutrophil-rich common nonneoplastic skin infiltrates. The eosinophil-rich cases included five insect bites. The neutrophil-rich cases included 9 inflammatory (hidradenitis suppurativa [n = 4], stasis ulcer [n = 2], ruptured cyst, rhynophyma, and Sweet syndrome); 12 infectious (bacterial [n = 8], viral [n = 2] and fungal [n = 2] etiologies); and 2 environmental (spider bites) cases. Atypical CD30-positive cells were found in 4 of 5 eosinophil-rich, 8 of 9 neutrophil-rich inflammatory, 6 of 12 neutrophil-rich infectious, and 2 of 2 neutrophil-rich environmental cases. Polymerase chain reaction analysis for B- and T-cell clonality and cell counts of neutrophils, eosinophils, plasma cells, B cells (using CD20), and T cells (using CD3) were performed in the cases that contained atypical CD30-positive lymphoid cells. CD30-positive cells averaged 4.8% of the cells counted in the areas where they were most concentrated. Of the 18 cases that amplified with polymerase chain reaction, all were polyclonal for T-cell receptor rearrangements; 10 were polyclonal and 8 oligoclonal for B-cell immunoglobulin rearrangements. There was no correlation between B-cell oligoclonality with CD30-positive cell counts, a particular disease, or a disease category. In conclusion, the presence of CD30-positive atypical lymphoid cells in 71.4% of the common nonneoplastic cases studied, even in the presence of clonal B-cell populations, warrants caution in the interpretation of these cells as malignant, particularly when dealing with the differential diagnosis of lymphomatoid papulosis or neutrophil-rich anaplastic large cell lymphoma.

Herbivore-induced allene oxide synthase transcripts and jasmonic acid in Nicotiana attenuata.

Exogenous jasmonate treatment of Nicotiana attenuata Torr. ex Wats. plants elicits durable resistance against herbivores and attack from its specialist herbivore, Manduca sexta, results in an amplification of the transient wound-induced increase in endogenous jasmonic acid levels (JA). To understand whether this "JA burst" is under transcriptional control, we cloned allene oxide synthase (AOS; EC 4.2.1.92), the enzyme that catalyzes the dehydration of 13(S)-hydroperoxy octadecatrienoic acid to an allene oxide, the first specific reaction in JA biosynthesis. An AOS cDNA coding for a 520 aa protein (58.6 kDa) with an isoelectric point of 8.74 was overexpressed in bacteria and determined to be a functional AOS. Southern blot analysis indicated the presence of more than one gene and AOS transcripts were detected in all organs, with the highest levels in stems, stem leaves and flowers. Attack by M. sexta larvae resulted in a sustained JA burst producing an endogenous JA amount 9-fold above control levels and 3-fold above maximum wound-induced levels, a response which could be mimicked by the addition of Manduca oral secretion and regurgitant to puncture wounds. M. sexta attack, wounding and regurgitant treatment transiently increased AOS transcript in the wounded leaf, but increases were not proportional to the JA response. Moreover, transcript accumulation lagged behind JA accumulation. Systemic wound-induced increases in AOS transcript, AOS activity or JA accumulation could not be detected. We conclude that increase in AOS transcript does not contribute to the initial increase in endogenous JA, but may contribute to sustaining the JA burst.