京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18509号 / 医博第3929号 / 新制||医||1005(附属図書館) / 31395 / 京都大学大学院医学研究科医学専攻 / (主査)教授 三森 経世, 教授 鈴木 茂彦, 教授 長田 重一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Atopic dermatitis (AD) is a common skin disease that is characterized by chronic, relapsing skin inflammation and eczematous, itchy lesions. In AD, systemic and local eosinophilia and basophilia is thought to contribute to disease progression in both acute and chronic lesions. It has been previously shown that in chronic allergic inflammatory diseases, tissue eosinophilia and basophilia may in part result from eosinophil/basophil (Eo/B) progenitors trafficking from the bone marrow and maturing in tissue in response to type 2 cytokines including IL-5 and IL-3. We therefore proposed that a similar mechanism could be contributing to the pathogenesis of AD. First, we compared lesional and non-lesional AD tissue, and found approximately 10-fold higher levels of Eo/B progenitors in the lesional tissue (p<0.05). As previous research has shown an increase in Eo/B progenitors in the airways of allergic asthmatics post inhaled allergen challenge, we next examined whether Eo/B progenitors increased locally in the acute phase of AD using the intradermal allergen challenge model. Compared to intradermal diluent challenge there was an increase in Eo/B progenitors (5.5-fold), eosinophils (18-fold) and basophils (2.5-fold) 24 hours post intradermal allergen challenge (all p<0.05). These increases were consistent with findings in allergic airways. Lastly, we examined the relationship between disease severity and Eo/B progenitors in inflamed lesional (chronic) and allergen-challenged (acute) tissue. We found that Eo/B progenitors in lesional tissue positively correlated with disease severity (EASI R=0.71, p<0.05 and SCORAD R=0.65, p<0.05), while in allergen-challenged tissue a trend was seen for a positive correlation between Eo/B progenitors and disease severity (EASI R=0.48, p=0.07 and SCORAD R=0.46, p=0.09). These results highlight the potential involvement of Eo/B progenitors in the disease pathogenesis of AD. / Thesis / Master of Science (MSc) / Atopic dermatitis is a common skin disease that is characterized by chronic, relapsing skin inflammation and eczematous, itchy lesions. In other allergic diseases, a cell called the “eosinophil/basophil progenitor” contributes to the accumulation of inflammatory cells in the diseased organ. We proposed that eosinophil/basophil progenitors found in the skin may be contributing to the development of local allergic inflammation. In patients with moderate-to-severe atopic dermatitis we compared acute responses to intradermal allergen and chronic skin lesions to diluent-challenged and un-affected skin, respectively. Allergen-challenged skin had more eosinophil/basophil progenitors, mature eosinophils and basophils 24 hours’ post-challenge compared to unchallenged skin (p<0.05). Chronic skin lesions had more eosinophil/basophil progenitors than un-affected skin (p<0.05). The number of eosinophil/basophil progenitors positively correlated to disease severity as determined by EASI and SCORAD. Our results suggest that accumulation of eosinophil/basophil progenitors in skin of atopic dermatitis patients could support allergic inflammation and contribute to disease severity.

Anaphylaxis is a rapid, life-threatening hypersensitivity reaction. Until recently, it was mainly attributed to histamine released by mast cells activated by allergen crosslinking (XL) of FcεRI-bound allergen-specific IgE. However, recent reports established that anaphylaxis could also be triggered by basophil, macrophage and neutrophil secretion of platelet activating factor subsequent to FcγR stimulation by IgG/Ag complexes. I have investigated the contribution of Fyn and Lyn tyrosine kinases to FcγRIIb and FcγRIII signaling in the context of IgG-mediated passive systemic anaphylaxis (PSA). I found that mast cell IgG XL induced Fyn, Lyn, Akt, Erk, p38 and JNK phosphorylation. Additionally, IgG XL of mast cells, basophils and macrophages resulted in Fyn- and Lyn-regulated mediator release in vitro. FcγR–mediated activation was enhanced in Lyn-deficient (KO) cells, but decreased in Fyn KO cells, compared to wild type cells. More importantly, Lyn KO mice displayed significantly exacerbated PSA features while no change was observed for Fyn KO mice, compared to wild type littermates. Intriguingly, this work establishes that mast cells account for the majority of serum histamine in IgG-induced PSA. Taken together, these findings establish pivotal roles for Fyn and Lyn in the regulation of PSA and highlight their unsuspected functions in IgG-mediated pathologies.

Le paludisme, responsable du décès d’un million de personnes chaque année, reste un problème majeur de santé publique. Des études récentes ont évoqué des mécanismes immunopathologiques communs entre les manifestations allergiques et le paludisme, soutenus par l’existence d’un homologue parasitaire du facteur de relargage d’histamine humain (PfTCTP). Notre objectif était de déterminer l’implication des acteurs de la réponse allergique dans la gravité de l’accès palustre, et la capacité de la PfTCTP à moduler ces réponses.Trois groupes de sujets ont été recrutés dans des structures de santé à Dakar. Les patients infectés présentaient des taux élevés d’IgE totales et spécifiques, par rapport aux sujets sains, mais sans corrélation avec la gravité. A l’aide d’un test d’activation des basophiles basé sur l’expression du CD203c, nous avons montré que les basophiles de patients en accès simple présentaient un niveau d’activation basal significativement réduit. Ces mêmes patients présentaient des concentrations plasmatiques élevées en IL-10, suggérant un meilleur contrôle de leur réponse inflammatoire. Les basophiles de patients en accès grave présentaient une hyperréactivité à l’hémozoïne, ainsi qu’à des stimulations IgE-dépendantes (anti-IgE). Enfin, la présence de PfTCTP circulante a été associée à une plus grande réactivité des basophiles, tandis que l’acquisition d’anticorps contre cette protéine est associée à une protection envers une trop grande réactivité cellulaire.En conclusion, nos travaux soutiennent l’hypothèse d’une activation allergique excessive au cours du paludisme grave. Ce travail ouvre la voie à de nouvelles approches thérapeutiques. / Malaria is responsible of the death of a million person each year and remains a major public health problem. Recent studies have suggested the existence of common immunopathologic mechanisms between allergic manifestations and malaria, supported by the existence of a parasite homolog of the human histamine releasing factor (PfTCTP). Our objective was to determine i) the implication of allergic response actors in the severity of malaria, and ii) the ability of PfTCTP to modulate these responses.Three groups of subjects were recruited in health structures in Dakar. Infected patients presented high levels of total and specific IgE, compared to healthy controls, although not correlated with severity. With a basophil activation test based on CD203c expression, we demonstrated that basophils from mild malaria patients presented a significantly reduced basal level of activation which paralleled higher levels of IL-10, thus suggesting a better control of their inflammatory responses. Basophils from severe malaria patients showed an hyperreactivity to haemozoin and to IgE-dependent stimulations (anti-IgE). Finally, presence of circulating PfTCTP was associated with a higher basophil reactivity, whereas acquisition of anti-PfTCTP antibodies was associated with protection towards excessive cellular reactivity.In conclusion, our results support the hypothesis of an excessive allergic activation during severe malaria. This work might open the way to new therapeutic approaches.

En 1985 Kroto décrit le troisième allotrope du carbone, le fullerène, une sphère de 60 carbones d’1nm de diamètre aux caractéristiques physico-chimiques particulières. La réactivité chimique du C₆₀ est dominée par les réactions d’addition et sa grande affinité pour les radicaux libres grâce à ses 30 double-liaisons. Cette propriété a été explorée dans le stress oxydant, tant in vitro qu’in vivo, où l’équilibre redox est impliqué, comme dans les situations pathophysiologiques impliquant l’inflammation et la dégénérescence cellulaire. En particulier, un traitement au C₆₀ solubilisé dans de l’huile a permis de prolonger l’espérance de vie chez le rat. Le produit, commercialisé à travers le monde, n’a pas encore fait l’objet d’essai clinique. D’autre part certaines préparations peuvent contenir des impuretés. Il est donc important d’établir des critères de pureté et d’intégrité des préparations de C₆₀. Ce travail de thèse comporte deux parties. La première, physicochimique, nous a permis d’évaluer la pureté de préparations commerciales de C₆₀ de différentes origines faisant appel à différentes techniques d’analyse: microscopie électronique à balayage, diffraction aux rayons X, calorimétrie différentielle à balayage (DSC), analyse thermogravimétrique, chromatographie liquide (CLHP) ou en phase gazeuse couplée à la spectrométrie de masse (CG-SM), ainsi que la spectroscopie ultraviolet-visible ou infrarouge à transformée de Fourier (FTIR). La DSC est la technique de choix pour établir le critère de pureté et la FTIR la plus rapide. La CG-SM est nécessaire à l’identification des impuretés volatiles, tandis que la CLHP permet de détecter les fullerènes lourds et les dérivés du C₆₀. La deuxième partie a porté sur des aspects fonctionnels des fullerènes et nous avons, pour cela, utilisé des préparations pures selon les critères définis précédemment. Dans un premier temps, nous avons cherché à préciser le sous-compartiment cellulaire ciblé par le C₆₀ injecté in vivo chez la souris. Après administration d’une solution huileuse, les molécules de C₆₀ sont retrouvées dans le foie et la rate, à l’intérieur des cellules, parfois au niveau des mitochondries et du réticulum endoplasmique. La présence des molécules de C₆₀, au niveau des mitochondries a été corroborée par la mise en évidence de modifications spécifiques d’activité des enzymes de la mitochondrie (malate déshydrogénase et complexe I de la chaîne respiratoire). Dans un deuxième temps, nous avons abordé l’effet des fullerènes sur des cellules intervenant dans une dysrégulation immunologique où l’inflammation joue un rôle important : l’allergie. L’évènement cellulaire à l’origine des symptômes allergiques est la libération de médiateurs de l’inflammation et de la réponse immunitaire lors de l’activation dépendante des IgE des basophiles et des mastocytes. L’effet régulateur de C₆₀ et de quatre dérivés hydrosolubles, le fullérol, la β-cyclodextrine C₆₀, le dendro C₆₀ et le C₆₀ serinol-malonate, a été testé. L’innocuité des dérivés à des concentrations nanomolaires et leur pouvoir inhibiteur sur la dégranulation IgE et non IgE dépendante des lignées mastocytaires de rat a été vérifié in vitro. Dans un test d’activation cellulaire mesurant l’expression des marqueurs CD63 et CD203c par cytométrie de flux, nous montrons que les différents dérivés sont capables d’interférer ex vivo avec l’activation de basophiles de patients allergiques dans des conditions naturelles de sang total. Les taux d’inhibition dépendent des dérivés et des patients avec un maximum observé à 35% en présence de C₆₀ serinol-malonate. Ces inhibitions ont été reproduites sur des basophiles humains purifiés en étudiant des marqueurs d’activation supplémentaires CD107a et CD69. Les perspectives de ce travail portent sur la spécificité et les mécanismes d’inhibitions observés au niveau intracellulaire. Elles incluent, par exemple, l’étude des flux de calcium ou des protéines de fusion, ou des facteurs de transcription. / In 1985 Kroto discovered the third allotrope of carbon, fullerene, spherical molecule consists of 60 carbons with 1 nm in diameter with a specific physico-chemical characteristic. The chemical reactivity of C₆₀ is governed by addition reactions and its high affinity for scavenging free radicals thanks to its 30 double bonds. This property has been widely explored in the field of oxidative stress, in vitro and in vivo, where redox balance is involved, as physio-pathological situations involving inflammation and cellular degeneration. In particular, treatment with C₆₀ solubilized in olive oil extended life span in a rat experimental model. The product, marketed worldwide, has not yet been clinically tested. On the other hand, some preparations may contain impurities. It is therefore important to establish criteria for the purity and integrity of C₆₀ preparations. This thesis work consists of two parts. In the first physico-chemical part, a criterion of C₆₀ purity was established for evaluating the purity of several commercial preparations of C₆₀ with different origins using the following techniques: scanning electron microscopy, X-ray diffraction, Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), liquid chromatography and gas chromatography coupled to mass spectrometry (GC-MS), as well as ultraviolet-visible and Fourier transform infrared (FTIR) spectroscopy. The results show that FTIR is the easiest way to control the quality of C₆₀ and GC-MS is necessary for identifying volatile impurities, while HPLC remains essential for detecting other fullerenes and C₆₀ derivatives. The second part of the thesis deals with functional aspect of fullerenes and for this purpose we used the pure preparation of C₆₀ evaluated according to the previously defined criteria. In a first chapter, to precise the sub-cellular compartment targeted, the C₆₀ dissolved in olive oil were in vivo injected in mice. After administration, C₆₀ molecules were visualized in the liver and in the spleen, inside the cells and sometimes in mitochondria and endoplasmic reticulum. The targeting of [60]fullerene to the mitochondria was confirmed by a specific modification of the activities of mitochondrial enzymes (malate dehydrogenase and complex I of respiratory chain). In a second chapter we studied the effect of fullerenes on cells involved in an immune dysregulation where inflammation plays a role: allergy. The cellular mechanism at the basis of allergic symptoms is the release in circulation and tissues of mediators of inflammation and immune response from IgE-dependent activation of basophiles and mast cells. The regulatory effects of [60]fullerene and 4 hydrosoluble derivatives, fullerol, β-cyclodextrin [60]fullerene, dendro [60]fullerene and [60]fullerene serinol-malonate, were tested. In vitro experiments showed an absence of toxicity at nanomolar concentrations and inhibitory abilities on the IgE-dependent and -independent activation of the rat mast cell line (RBL). In a cellular activation test monitoring the expression of the degranulation and activation markers CD63 and CD203c on basophiles, by flow cytometry, we show that the various fullerenes are able also to inhibit the ex vivo activation of basophiles from peanut allergic patients in a natural physiological environment: in whole blood. Inhibition rates depend on patients and derivatives with a maximum inhibition observed at 35% in presence of [60]fullerene serinol-malonate. These inhibitions were reproduced on purified human basophiles by studying further activation markers CD107a and CD69. Working perspectives will be on the specificity and the mechanisms of inhibition by studying intracellularly calcium influx or the expression of fusion proteins and transcription factors.

<p>The recent and dramatic rise in allergic disease, coupled with the manifestation of the disease within the first years of life, suggests that <em>in utero</em> events are likely critically important to the inception of allergy. Epidemiological and experimental evidence suggest that both genetic predisposition and prenatal environmental exposures (e.g., <em>in utero</em> microbial exposures) play a role in modulating neonatal immunity and subsequent development of allergy. Of relevance to the work in this thesis, reports suggest that bacterial agents can directly alter myelopoiesis and, in connection to allergy, we have previously shown that cord blood (CB) progenitors from high-atopic risk infants demonstrate altered hematopoietic responses. However, whether CB progenitor cell hematopoietic responses are directly altered by microbial stimulation, and what effect maternal atopy has on these responses are unclear. Therefore, this thesis examines the influences of bacterial lipopolysaccharide (LPS) stimulation (innate immunity), maternal atopy, and adaptive immune stimuli (representative of an atopic milieu) on CB progenitor cell eosinophilopoiesis. We show that CB progenitors from healthy, pregnant women respond to LPS through increased eosinophil-basophil (Eo/B) colony forming units (CFU) via the mitogen-activated protein kinase (MAPK) signalling pathway (Chapter 2), whereas the presence of maternal atopy (as defined by skin prick test positivity) is associated with reduced CB CD34⁺ cell LPS-induced Eo/B CFU formation (Chapter 3). To investigate the potential mechanism of reduced eosinophilopoiesis in high-atopic risk infants, CB progenitors stimulated with IL-4 (a surrogate <em>ex vivo</em> for maternal atopy), but not IL-13, demonstrate reduced LPS-induced MAPK activation and Eo/B CFU formation (Chapter 4). This novel work provides insight into mechanisms relating to the influence of maternal atopy and/or potential intrauterine exposures (e.g., prenatal cytokines) on the responsiveness of CB progenitor cells to LPS, which may be of key importance for the development of atopic illnesses. These observations may help in the generation of novel biomarkers and therapeutic targets for childhood atopy.</p> / Doctor of Philosophy (PhD)

<p>Mast cells are key effector cells in allergic and inflammatory diseases. However, their primary role is most likely in host defence against parasitic and bacterial infections. Mast cells are a particularly rich source of serine proteases. These proteases belong to the chymase or the tryptase family, which are encoded from the mast cell chymase and the multigene tryptase loci, respectively. To better understand the biological functions and the molecular evolution of these enzymes we have studied the organisation of these two loci in species ranging from fish to human. We show that the mast cell chymase locus has evolved from a single founder gene to a complex locus during the past 200 Myr of mammalian evolution. Forty-five fish candidate genes for hematopoietic serine proteases were also identified. However, in phylogenetic analyses none of them grouped with individual branches holding mammalian mast cell chymase locus genes, indicating an independent parallel evolution in fish. </p><p>Studies of the evolution of the multigene tryptase locus showed that this locus has been highly conserved between marsupials and eutherians. However, no genes belonging to the individual subfamilies identified in eutherians could be identified in fish, amphibians or in birds, which also here indicates parallel evolution.</p><p>To study the evolution of specific cleavage specificities associated with these proteases, the extended cleavage specificity of opossum α-chymase was determined and found to be nearly identical to human mast cell chymase and the major mouse mast cell chymase mMCP-4. This indicates a strong pressure to maintain this specificity during mammalian evolution.</p><p>Basophils are rare blood cells with functions similar to mast cells that when mature almost completely lack mRNA. To study the proteome and to primarily characterize the granule protein content of basophils, an <i>in vitro</i> purification protocol was developed to obtain transcriptionally active umbilical cord blood-derived basophil precursors.</p>

THESIS SUMMARY Food allergy is one of the frequent disorders and its incidence in paediatric as well as adult population is continuously rising, having doubled in the last two decades. Although wheat belongs to major food allergens and is a staple food in most diets, we have only little knowledge of wheat proteins causing IgE mediated hypersensitivity reaction. Diagnostic approaches of food allergy to wheat have a high sensitivity, but low specificity. Poor predictability and specificity may be associated with the insufficient purity of wheat extracts used in sIgE assays or with the lack of major allergens in these extracts. In the first step, we characterized 19 potential allergens recognised by IgE Abs of allergic patients, using proteomic techniques (1-DE, 2-DE, MALDI-TOF, QTOF and LCQDECA nLC-MS/MS ion trap technique). We identified these IgE-binding molecules such as: α-amylase inhibitors, β-amylase, profilin, serpin, β-D-glucan exohydrolase and 27K protein. To quantify sIgE in patient's sera we developed ELISA using the whole wheat extract and two commercially available α-amylase inhibitors. Second, we developed a procedure that allows isolation of wheat allergens from natural sources using Rotofor cell and HPLC. Twenty-seven potential wheat allergens have been successfully identified; of these, the...

<p>Mast cells are long-lived effector cells of importance for both acute and chronic inflammations. Mast cells can be activated in many different ways, leading to the release of inflammatory mediators. In contrast to most other inflammatory cells, activated mast cells have the capacity to recover, regranulate and thereby be activated again. </p><p>In this thesis I have investigated the mechanisms involved in regulating activation-induced mast cell survival. We have found that cross-linking of FcεRI-bound IgE with an antigen (IgER-CL) induces a survival program in mast cells. Upon IgER-CL, mouse and human mast cells upregulate the pro-survival Bcl-2 family gene A1/Bfl-1. A1^-/- mast cells degranulate upon FcεRI activation but they cannot recover most likely due to the lack of A1. Sensitized and provoked A1^-/- mice exhibit lower amounts of mast cells compared to littermate controls. In contrast to mast cells, no Bfl-1 expression or survival promotion can be detected in basophils after IgER-CL. Another mast cell secretagogue, an adenosine receptor agonist, neither promoted upregulation of A1 nor survival.</p><p>Although it is well established that mast cell survival is dependent on stem cell factor (SCF), it has not been described how this process is regulated. We have found that SCF promotes survival through Akt-mediated inhibition of the forkhead transcription factor FOXO3a and its transcriptional target Bim, a BH3-only pro-apoptotic protein. SCF-treatment prevents upregulation of Bim protein expression and leads to an upregulation of Bim phosphorylation through PI3-kinase and MEK-dependent pathways. Overexpression of FOXO3a causes an upregulation of Bim and induces mast cell apoptosis, even in the presence of SCF. </p><p>Taken together, the work in this thesis demonstrates that A1/Bfl-1 and Bim play key roles in mast cell survival. These findings might be of importance in understanding the mechanisms of mast cell longevity and hence for possible new therapeutics used for mast cell-associated inflammations.</p>

Mast cells are long-lived effector cells of importance for both acute and chronic inflammations. Mast cells can be activated in many different ways, leading to the release of inflammatory mediators. In contrast to most other inflammatory cells, activated mast cells have the capacity to recover, regranulate and thereby be activated again. In this thesis I have investigated the mechanisms involved in regulating activation-induced mast cell survival. We have found that cross-linking of FcεRI-bound IgE with an antigen (IgER-CL) induces a survival program in mast cells. Upon IgER-CL, mouse and human mast cells upregulate the pro-survival Bcl-2 family gene A1/Bfl-1. A1-/- mast cells degranulate upon FcεRI activation but they cannot recover most likely due to the lack of A1. Sensitized and provoked A1-/- mice exhibit lower amounts of mast cells compared to littermate controls. In contrast to mast cells, no Bfl-1 expression or survival promotion can be detected in basophils after IgER-CL. Another mast cell secretagogue, an adenosine receptor agonist, neither promoted upregulation of A1 nor survival. Although it is well established that mast cell survival is dependent on stem cell factor (SCF), it has not been described how this process is regulated. We have found that SCF promotes survival through Akt-mediated inhibition of the forkhead transcription factor FOXO3a and its transcriptional target Bim, a BH3-only pro-apoptotic protein. SCF-treatment prevents upregulation of Bim protein expression and leads to an upregulation of Bim phosphorylation through PI3-kinase and MEK-dependent pathways. Overexpression of FOXO3a causes an upregulation of Bim and induces mast cell apoptosis, even in the presence of SCF. Taken together, the work in this thesis demonstrates that A1/Bfl-1 and Bim play key roles in mast cell survival. These findings might be of importance in understanding the mechanisms of mast cell longevity and hence for possible new therapeutics used for mast cell-associated inflammations.