Characterisation of an immune-modulating peptide secreted by a helminth worm

University of Technology Sydney. Faculty of Science.Parasitic worms (helminths) have evolved mechanisms to potently modulate the mammalian immune response to ensure their long-term survival, while concomitantly preventing excessive tissue pathology within the host. The outcome of this activity is a potent suppression of mammalian pro-inflammatory Th1 and Th17 immune responses. This immune-modulatory phenomenon is attributable to the molecules excreted/secreted by helminths as they migrate through their human hosts. The identification of these molecules has the potential to contribute to the development of novel therapeutics for the treatment of autoimmune diseases as these diseases are mediated by pro-inflammatory Th1 and Th17 immune responses. It has previously been shown that the delivery of a single peptide, FhHDM-1, which is excreted/secreted from the helminth, Fasciola hepatica, prevented the development of murine type 1 diabetes and multiple sclerosis. The aetiological similarity between these two diseases, is the establishment of the pro-inflammatory environment by macrophages and neutrophils. Therefore, it was hypothesised that FhHDM-1 likely mediated its protective effect through anti-inflammatory mechanisms directed at these cells. In this study, it was confirmed that FhHDM-1, specifically interacted with both murine and human neutrophils and macrophages. Furthermore, it was demonstrated that FhHDM-1 modulated the activity of these cells, by inhibiting the secretion of pro-inflammatory cytokines/chemokines, which, in turn, prevented further activation of pro-inflammatory T cells and dendritic cells. The use of transcriptional profiling revealed that, of the 41,436 genes analysed in macrophages, treatment with FhHDM-1 altered the expression levels of only 6 of these. Of these, only the expression level of SerpinB2 was increased, and this was shown to subsequently mediate the suppression of pro-inflammatory cytokine secretion by T cells. In the context of an inflammatory stimulus, FhHDM-1 regulated the expression of numerous pro-inflammatory genes in macrophages. Pathway analysis predicted that this anti-inflammatory activity was mediated through the activation of PPAR-γ pathways. This is the first report of a PPAR-γ agonist being secreted by a helminth parasite as a mechanism of modulating mammalian innate immune responses. Importantly, a homologous parasite peptide from a related trematode parasite demonstrated the same activity suggesting a conserved mechanism of action among parasite helminths. Analysis of the sequence of the FhHDM-1 peptide, combined with immunological assays of peptide derivatives, supported the discovery of the minimally active sequence, FhHDM-1.C2. This peptide contained both the amphipathic C-terminus region, previously identified as functional, and a sequence of 5 amino acids (KARDR), which was newly identified as essential for the binding and internal localisation of FhHDM-1. This C2 derivative mimicked the activity of the full length peptide in every way, such as the ability to bind and be internalised by macrophages, to increase macrophage lysosomal pH, to induce the expression of SerpinB2, and to inhibit the production of pro-inflammatory cytokines. In summary, this thesis has newly identified the binding and active domains of the parasite immune-modulatory peptide, FhHDM-1, and discovered the novel mechanisms by which the peptide regulates pro-inflammatory innate immune responses. Combined, these findings have significantly advanced the progress towards translation of the FhHDM-1 peptide for therapeutic use in immune-mediated diseases

Evaluation of Itch by Using NC/NgaTnd Mice: A Model of Human Atopic Dermatitis

Atopic dermatitis (AD) is the extremely complicated syndrome that various abnormalities develop in a heap. There are various factors in patients for the onset and exacerbation of AD, including genetic cofactors of individuals, environmental factors, the failure of the skin barrier function, unfavorable regulation of the immune system, and the hypersensitivity of sensory nerves. In recent years, there have been many trials of the drug discovery that targets itch, because itch is one of the most serious clinical symptoms of AD. The selection of the suitable animal model that represents the condition of patients, as well as innovative analyzing protocols that can precisely evaluate itch, is indispensable for investigation of an effective drug for AD. In the paper, the unique spontaneous animal model for AD (NC/NgaTnd mice) and the novel quantification system of the laboratory animals that may bring a great progress in the future study of itch are outlined

Mast Cell Tumors

Mast cell tumor is one of the major cutaneous tumors in dogs. Though the etiology of MCTs is not completely understood, it becomes clear that approximately 10–20% MCTs express mutant KIT receptors with ligand‐independent phosphorylation. Tyrosine kinase inhibitors targeting KIT exert antitumor effects on malignant proliferation of mast cells with or without gene mutations. However, the efficacy of KIT inhibitors on dogs with MCTs has been limited. In this chapter, we would like to outline the general understandings of mast cells such as the process of its differentiation and proliferation, and what has been revealed regarding the mechanism of tumorigenesis and therapeutic approaches. In particular, KIT mutation‐related evidences and therapeutic approaches in the future are discussed

Live Imaging of Axolotl Digit Regeneration Reveals Spatiotemporal Choreography of Diverse Connective Tissue Progenitor Pools

Connective tissues—skeleton, dermis, pericytes, fascia—are a key cell source for regenerating the patterned skeleton during axolotl appendage regeneration. This complexity has made it difficult to identify the cells that regenerate skeletal tissue. Inability to identify these cells has impeded a mechanistic understanding of blastema formation. By tracing cells during digit tip regeneration using brainbow transgenic axolotls, we show that cells from each connective tissue compartment have distinct spatial and temporal profiles of proliferation, migration, and differentiation. Chondrocytes proliferate but do not migrate into the regenerate. In contrast, pericytes proliferate, then migrate into the blastema and give rise solely to pericytes. Periskeletal cells and fibroblasts contribute the bulk of digit blastema cells and acquire diverse fates according to successive waves of migration that choreograph their proximal-distal and tissue contributions. We further show that platelet-derived growth factor signaling is a potent inducer of fibroblast migration, which is required to form the blastema.Fil: Currie, Joshua D.. Technische Universität Dresden; Alemania. Max Planck Institute of Molecular Cell Biology and Genetics; AlemaniaFil: Kawaguchi, Akane. Technische Universität Dresden; AlemaniaFil: Traspas, Ricardo Moreno. Technische Universität Dresden; AlemaniaFil: Schuez, Maritta. Technische Universität Dresden; AlemaniaFil: Chara, Osvaldo. Technische Universität Dresden; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física de Líquidos y Sistemas Biológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física de Líquidos y Sistemas Biológicos; ArgentinaFil: Tanaka, Elly M.. Technische Universität Dresden; Alemania. Max Planck Institute of Molecular Cell Biology and Genetics; Alemani

A suitable stereoisomer of vibrioferrin probes for iron uptake of Vibrio parahaemolyticus

Suitable Stereostructures of vibrioferrin probes for iron uptake of Vibrio parahaemolyticus was revealed. Stereoisomers of dansyl labeled vibrioferrin at the 2′′-position were synthesized and their uptake activities were evaluated. Vibrio parahaemolyticus take in both isomers at the 2′′-position. In addition to Vibrio parahaemolyticus, several bacteria have also taken up the (R)-isomer

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