CX3CR1 Polymorphisms are associated with atopy but not asthma in German children

Chemokines and their receptors are involved in many aspects of immunity. Chemokine CX3CL1, acting via its receptor CX3CR1, regulates monocyte migration and macrophage differentiation as well as T cell-dependent inflammation. Two common, nonsynonymous polymorphisms in CX3CR1 have previously been shown to alter the function of the CX3CL1/CX3CR1 pathway and were suggested to modify the risk for asthma. Using matrix-assisted laser desorption/ionization time-of-flight technology, we genotyped polymorphisms Val249Ile and Thr280Met in a cross-sectional population of German children from Munich (n = 1,159) and Dresden ( n = 1,940). For 249Ile an odds ratio of 0.77 (95% confidence interval 0.63-0.96; p = 0.017) and for 280Met an odds ratio of 0.71 ( 95% confidence interval 0.56-0.89; p = 0.004) were found with atopy in Dresden but not in Munich. Neither polymorphism was associated with asthma. Thus, amino acid changes in CX3CR1 may influence the development of atopy but not asthma in German children. Potentially, other factors such as environmental effects may modify the role of CX3CR1 polymorphisms. Copyright (c) 2007 S. Karger AG, Basel

Transcriptional Profiling of Non-Small Cell Lung Cancer Cells with Activating EGFR Somatic Mutations

Activating somatic mutations in epidermal growth factor receptor (EGFR) confer unique biologic features to non-small cell lung cancer (NSCLC) cells, but the transcriptional mediators of EGFR in this subgroup of NSCLC have not been fully elucidated.Here we used genetic and pharmacologic approaches to elucidate the transcriptomes of NSCLC cell lines. We transcriptionally profiled a panel of EGFR-mutant and -wild-type NSCLC cell lines cultured in the presence or absence of an EGFR tyrosine kinase inhibitor. Hierarchical analysis revealed that the cell lines segregated on the basis of EGFR mutational status (mutant versus wild-type), and expression signatures were identified by supervised analysis that distinguished the cell lines based on mutational status (wild-type versus mutant) and type of mutation (L858R versus Delta746-750). Using an EGFR mutation-specific expression signature as a probe, we mined the gene expression profiles of two independent cohorts of NSCLC patients and found the signature in a subset. EGFR tyrosine kinase inhibitor treatment regulated the expression of multiple genes, and pharmacologic inhibition of the protein products of two of them (PTGS2 and EphA2) inhibited anchorage-independent growth in EGFR-mutant NSCLC cells.We have elucidated genes not previously associated with EGFR-mutant NSCLC, two of which enhanced the clonogenicity of these cells, distinguishing these mediators from others previously shown to maintain cell survival. These findings have potential clinical relevance given the availability of pharmacologic tools to inhibit the protein products of these genes

Development and characterization of aptamer-amphiphiles against fractalkine for targeted drug delivery

University of Minnesota Ph.D. dissertation. December 2013. Major: Chemical Engineering. Advisor: Efrosini Kokkoli. 1 computer file (PDF); ix, 111 pages.A foundation of modern diagnostics and therapeutics is the ability to non-covalently bind to a molecule of interest. These affinity molecules are behind a broad array of products ranging from therapeutics to HIV tests. Currently, antibodies are used as the affinity molecule. Despite the success of antibodies, alternatives are needed due to high development and production costs, and issues with stability. Aptamers are an exciting alternative to antibodies. Aptamers are short sequences of single stranded DNA or RNA that bind molecular targets with high affinity and specificity. Aptamers are inexpensive to produce, are very stable, have long shelf lives, and could potentially replace antibodies in a number of applications. One potential application of aptamers is targeted drug delivery. The goal of targeted drug delivery is to selectively deliver a therapeutic payload to the site of action thereby increasing efficacy and decreasing side effects. Fractalkine is a cell surface protein expressed at sites of inflammation. It is expressed on several types of cancerous tissues and it is involved in the patheogenisis of arthritis, asthma, and atherosclerosis. This work describes the development and characterization of an aptamer that binds fractalkine with high affinity. The aptamer was modified with a hydrophobic tail, creating an aptamer-amphiphile, for use in a model drug delivery vesicle called a liposome. The aptamer-amphiphile was optimized for a high affinity interaction with fractalkine by adding a spacer molecule between the aptamer headgroup and the hydrophobic tail. The optimized amphiphile had high affinity for fractalkine and self-assembled into micelles and an interesting nanotape morphology. Finally, as a proof of concept, the optimized aptamer-amphiphile was incorporated into a liposome and targeted to fractalkine expressing cells. This work highlights the development of aptamers as affinity ligands, and demonstrates their use as potential drug delivery agents

Isolation, purification and partial characterisation of cancer procoagulant from placental amnion-chorion membranes and its role in angiogenesis inflammation and metastasis

Cancer procoagulant (EC 3.4.22.26) is an enzyme that is derived from tumour and foetal tissue, but not normal tissue. It is a direct activator of factor X and has been isolated from amnion-chorion membranes as well as from extracts and cells from human melanoma. The presence of cancer procoagulant has been associated with the malignant phenotype, as well as having a particularly high activity in metastatic cells. Cancer procoagulant activity is elevated in the serum of early stage breast cancer patients and decreased to normal in the advanced stages of the disease. In this study, cancer procoagulant was successfully isolated from amnion-chorion membranes and purified to homogeneity. The molecular weight of cancer procoagulant was determined using SDS-PAGE and was found to be 68 kDa. Cancer procoagulant was delipidated and it was shown that its activity was increased by the presence of lipids in a dose-dependent manner. Recovery of cancer procoagulant after delipidation is poor, consequently, a larger mass of sample is required to obtain sufficient amounts of delipidated material for N-terminal amino acid analysis. The optimum pH of cancer procoagulant was determined to be pH 8 and its optimal temperature was found to be 50°C. Novel synthetic substrates were designed to assay for cancer procoagulant activity. Currently, 2 potential candidates have been identified, namely, PQVR-AMC and AVSQSKP-AMC. Cancer procoagulant-induced expression of cytokines is differently modulated in the less aggressive MCF-7 cell line as compared to the metastatic and more aggressive MDA-MB-231 cell line. There are marked similarities in the inflammatory response produced by cancer procoagulant in hTERT-HDLEC and MDA-MB-231 cells, which are both associated with migratory capacity. Furthermore, cancer procoagulant-induced PDGF-β expression in hTERT-HDLEC and MDA-MB-231 cells could point to involvement of cancer procoagulant in wound healing and metastatic spread, respectively. Cancer procoagulant induced the motility of MDA-MB-231, MCF-7 and hTERT- cells in vitro in a time- and dose-dependent manner. Together, these results suggest that cancer procoagulant plays a role in the migration of breast cancer cells as well as the migration of endothelial cells

Comparaison de différentes approches méthodologiques dans l'identification de déterminants génétiques de susceptibilité ou de protection pour l'asthme

L'asthme est une maladie respiratoire chronique qui affecte autant les enfants que les adultes et qui se présente sous diverses manifestations cliniques. Cette maladie est également reconnue comme un trait complexe pUIsque plusieurs facteurs environnementaux et génétiques sont impliqués dans son développement. Les déterminants génétiques de susceptibilité ou de protection à l'asthme interagissent entre eux de même qu'avec l'environnement dans son développement. Depuis les dernières décennies, les études d'association ont permis d'identifier plus de 170 gènes associés à l'asthme ou à ses manifestations cliniques. Malgré cet avancement des connaissances en génétique de l'asthme, la confirmation des associations déjà observées et l'identification de nouveaux déterminants génétiques fait l'objet d'une recherche très active. C'est dans un tel contexte que le principal objectif de la présente thèse s'inscrit, à savoir l'identification de déterminants génétiques de susceptibilité ou de protection pour l'asthme. Pour ce faire, de nouvelles approches méthodologiques ainsi que des approches plus classiques ont été employées pour mener à terme les six études d'association présentées. Grâce à méthodologies novatrices, quatre nouvelles associations génétiques positives ont été mises en évidence avec les gènes CX3CR1, ALOX15, PLAU et PTPRE. De tels résultats ont permis, a priori, de démontrer l'utilité des nouvelles approches employées dans les études d'association génétique ' et de démontrer leur efficacité. L'acquisition de ces nouvelles connaissances a également mené à l'élaboration de nouvelles hypothèses de recherche et les projets en cours devraient améliorer la compréhension des mécanismes biologiques en cause dans l'asthme. Finalement, l'étude plus approfondie de ces gènes permettra, éventuellement, de développer de nouvelles thérapies et de surcroît, améliorer les conditions de vie des personnes asthmatiques

Roles of polymorphisms and expression of genes coding for chemokines CX3C ligand 1 and CXC ligand 16 and their receptors in the development and progression of multiple sclerosis in Serbia

Multipla skleroza je hroniĉna inflamatorna, autoimunska, demijelinizaciona i neurodegenerativna bolest centralnog nervnog sistema (CNS-a). Hemokini i njihovi receptori predstavljaju znaĉajne medijatore inflamacije koji uĉestvuju u patogenezi odreĊenih hroniĉnih inflamatornih i autoimunskih bolesti meĊu kojima je i multipla skleroza. Ciljni hemokini u ovoj studiji, CX3C ligand 1 (CX3CL1) i CXC ligand 16 (CXCL16), specifiĉni su po tome što postoje u dve forme - kao transmembranski adhezivni molekuli i kao solubilni hemoatraktanti koji nastaju nakon proteolitiĉkog seĉenja vanćelijskih hemokinskih domena njihovih transmembranskih formi. U toku inflamatornog odgovora, na membrani endotelnih vaskularnih ćelija eksprimirani su CX3CL1 i CXCL16, a na membrani leukocita receptori za CX3CL1 (CX3CR1) i CXCL16 (CXCR6), te ovi hemokini i njihovi receptori posreduju u prodiranju leukocita iz krvi u tkivo zahvaćeno inflamacijom, podsticanjem hemotaksije i adhezije leukocita za aktivirani endotel krvnog suda. Ova studija obuhvata genetsko-epidemiološku analizu polimorfizama zamena pojedinaĉnih nukleotida u kodirajućim regionima gena, koje rezultuju zamenama aminokiselina. To su polimorfizmi V249I i T280M u genu za CX3CR1, i I123T i A181V u genu za CXCL16. U prethodnim studijama je pokazano da ovi genski polimorfizmi menjaju funkcionalna svojstva CX3CR1 i CXCL16, kao i da su asocirani sa patogenezom odreĊenih hroniĉnih inflamatornih bolesti. Uzimajući to u obzir, ova studija je imala za cilj da po prvi put ispita asocijaciju navedenih polimorfizama u genima za CX3CR1 i CXCL16 sa nastankom i progresijom multiple skleroze. Primenom alel-specifiĉne PCR metode i PIRA PCR-RFLP metode detektovani su genotipovi polimorfizama V249I i T280M u genu za CX3CR1, kod zdravih kontrola i pacijenata sa multiplom sklerozom. UtvrĊeno je da haplotip I249T280 u genu za CX3CR1 ima znaĉajno veću uĉestalost kod pacijenata sa relapsno-remitentnom (RR) formom, u odnosu na pacijente sa sekundarno-progresivnom (SP) formom multiple skleroze, što znaĉi da ovaj haplotip ima protektivni efekat na progresiju RR u SP formu bolesti...Multiple sclerosis is a chronic inflammatory, autoimmune, demyelinating and neurodegenerative disease of the central nervous system (CNS). Chemokines and their receptors are important mediators of inflammation, which are involved in pathogenesis of certain chronic inflammatory and autoimmune diseases including multiple sclerosis. Chemokines of interest in this study, CX3C ligand 1 (CX3CL1) and CXC ligand 16 (CXCL16), are specific in that they can exist either as transmembrane adhesion molecules or soluble chemoattractants being generated by proteolytic cleavage of their transmembrane forms’ extracellular domains. During the inflammatory response, CX3CL1 and CXCL16 are expressed on the surface of vascular endothelium, while the leukocytes produce membrane receptors for CX3CL1 (CX3CR1) and CXCL16 (CXCR6). Therefore, these chemokines and their receptors mediate the infiltration of leukocytes from blood into the inflamed tissue areas, by stimulation of both chemotaxis and adhesion of leukocytes to the activated endothelium of blood vessels. This study is based on genetic epidemiological analysis of single nucleotide polymorphisms, which are located in the coding regions of genes and result in amino acids’ substitutions. These are V249I and T280M substitutions in the gene coding for CX3CR1, and I123T and A181V substitutions in the gene coding for CXCL16. In previous studies these polymorphisms have been associated with the functional properties of CX3CR1 and CXCL16 as well as the pathogenesis of certain chronic inflammatory diseases. Therefore, this study aimed to investigate the association of the polymorphisms in CX3CR1 and CXCL16 genes with the development and progression of multiple sclerosis. Using the allele-specific PCR and PIRA PCR-RFLP methods, genotypes of CX3CR1 V249I and T280M polymorphisms were detected in healthy controls and patients with multiple sclerosis. Following statistical analysis showed significantly higher frequency of CX3CR1 I249T280 haplotype in patients with relapsingremitting (RR) form, compared to patients with secondary-progressive (SP) form of multiple sclerosis, so this haplotype had a protective effect on progression of RR to SP form of the disease..

Lympho-epithelial cross talk in the gut: implications for maintaining and restoring immune homeostasis

Abstract Intestinal immunological environment is shaped by a continuous cross-talk involving three major components: intestinal epithelium, immune system and local microbiota. This work intended to investigate the role of lympho-epithelial interactions in response to food components and microorganisms. As part of this work the role of the immune-derived cytokine interleukin (IL)-12 in development of food allergy has been investigated. It was previously found that in peanut-sensitized mice there was decreased level of IL-12 in the intestine. We have observed that this is accompanied with increase in thymic stromal lymphopoietin (TSLP), a cytokine produced by the intestinal epithelium and indispensable for development of allergy. Oral delivery of recombinant Lactococcus lactis secreting bioactive IL-12 resulted in amelioration of the allergic symptoms and decrease in TSLP, thus suggesting a regulatory interaction between these two cytokines. Further investigation of the mechanism of this cross-regulation revealed that intestinal epithelial cells express incomplete but functional IL-12 receptor. However, mice deficient in IL-12 signalling displayed normal levels of TSLP implying involvement of other factors in the IL-12/TSLP axis. In addition, the availability of mice defective in IL-12 associated pathways prompted us to test the hypothesis that alteration of the cytokine network in the gut may contribute to shape the intestinal microbiota. Thus, by using 16S pyrosequencing we have studied the composition of the gut microbiota in mice deficient for IL-12p40, IL-12Rβ2, and IFN-γ in comparison to WT mice. In parallel, we have monitored the metabolome of the microbiota and the host intestinal tissue. Finally, we have described a novel pathogen-exclusion mechanism mediated by CX3CR1+ cells that migrate into the intestinal lumen upon Salmonella infection. This event is orchestrated by a lympho-epithelial crosstalk involving MyD88-dependant epithelial signal. CX3CR1-dependant migration is vital for pathogen protection in the early stages of infection

Chemotactic signals released during Burkitt’s lymphoma cell death

Tumour-associated macrophages (TAMs) have been shown to play an important role in tumour survival and progression. Thus, high numbers of macrophages in the tumour tissue are often associated with a poor prognosis. Identification of factors responsible for recruiting macrophages to the sites of different types of tumours might help to develop more effective cancer treatment. Burkitt's lymphoma (BL) is characterised by uncontrolled cell proliferation, high rate of spontaneous apoptosis and significant macrophage infiltration. Although BL cells undergo extensive apoptosis, in situ their corpses are cleared very effectively by macrophages infiltrating the tumour. It is now widely believed that dying cells are themselves able to release chemotactic molecules to ensure macrophage chemotaxis and subsequent clearance of their site of death. Previous work carried out in this laboratory identified fractalkine/CX3CL1 (FKN) released from dying BL cells to be an important player in macrophage chemotaxis to BL. Yet, these results have also indicated that FKN may not be the only chemokine involved in this process. Following from those observations, the first part of this work focused on examination of the potential role of monocyte chemoattractant protein-1 (MCP-1) in macrophage recruitment to BL. Despite the initial promising results, careful analysis of the data obtained by various techniques led to the conclusion that MCP-1 is, probably, not expressed by BL cells. Subsequently, effort was concentrated on understanding mechanisms regulating FKN processing during cell death. The studies performed before in this laboratory identified a new form of FKN to be present in apoptotic BL cells and showed that this is the form that is, most likely, responsible for mediating macrophage migration. Here, this apoptosis-related 60 kDa FKN was found to be a likely caspase-3 cleavage product. Moreover, it was demonstrated that FKN and active caspase-3 are released together in apoptotic BL cell-derived microparticles, suggesting that the proteolytic events could take place also extracellularly. In the final results chapter the differences between BL cell lines in the way they process FKN during cell death were revealed and a new cell death-associated 55 kDa FKN was observed. Through several lines of evidence, this new form was identified to be a possible product of calpain-mediated proteolysis. To conclude, this work provides the first evidence for a possible direct participation of the two major cell death executioner proteases – caspases and calpains, in production of ‘find me’ signals for macrophages and thus, ensuring effective clearance of dying cells. These results indicate that FKN cleavage and release might be of key importance during cell death. Moreover, the studies presented here contribute to better understanding of the process of FKN secretion