Regulation of the immune system and of uterine tissue homeostasis, growth, and remodelling are deeply intertwined during pregnancy and are essential for successful reproduction. Recent findings showed that tissue-resident innate lymphoid cells (ILCs) are crucial regulators of both physiology and pathology of the tissues they populate. Uterine natural killer (uNK) cells are a subtype of ILCs known to regulate trophoblast invasion, uterine vascular adaptation to pregnancy, and foetal growth. We recently described additional types of ILCs in the uterus of women and mice. However, the role of these ILCs during reproduction is unknown. Among them, group 2 ILCs (ILC2s) have been previously characterised in other tissues, in which they modulate immune cells and tissue homeostasis by producing type-2 cytokines and growth factors (i.e. IL-4, IL-5, IL-13, and Amphiregulin). Based on these premises, I hypothesized that uterine ILC2s (uILC2s) regulate uterine immune homeostasis and thus contribute to successful reproduction. To test this, I first characterised the uILC subtypes present in humans and mice at various stages of the reproductive cycle. Secondly, I addressed the functional role of uILC2s during pregnancy by taking advantage of a uILC2 knockout mouse model. My results show that uterine ILC2s represent < 1% and < 0.1% of murine and human uterine leukocytes, respectively. However, as they can quickly produce large amounts of cytokines, uILCs are capable of potently affect both other immune cells and the surrounding tissue. Indeed, I found that compared to other tissue-resident ILC2s, uILC2s produce high levels of IL-5 and Areg even in the absence of any stimulation. On the contrary, non-uterine ILC2s mainly produce IL-13, which is lowly expressed by uILC2s. To further characterize the tissuespecific properties of uILC2s, I then performed RNAseq on uILC2s isolated from virgin, midgestation, and term murine uterus, and I compared their transcriptomes with those of ILC2s from lung, intestine, and bone marrow. Interestingly, uILC2s specifically express granzymes and genes typical of regulatory T cells. Therefore, uILC2s have tissue-specific properties and are modulated during pregnancy. Furthermore, the ability of uILC2s to produce IL-5 and Areg suggests that they may be crucial in the regulation of uterine type-2 immunity. I then studied the phenotype of $Rora^{flox/flox}Il7ra^{cre/wt}$(ILC2KO) mouse models, as well as that of mice lacking the ILC2 activating cytokine IL-33 ($IL33^{cit/cit}$; IL33KO). I examined the immune microenvironment in both the myometrium and decidua in ILC2KO mice and found alterations in type-2 cytokines and myeloid cell homeostasis. In particular, in absence of ILC2s, IL-4 and IL-5 are dramatically reduced, IL-13 is absent, and decidual inflammatory cytokines IL1β and IL-6 are increased. Furthermore, uterine dendritic cells (uDC), uterine macrophages (uMac), and uterine neutrophils (uN) increase, while uterine eosinophils (uEo) are virtually absent. These results show that uILC2s regulate uterine type-2 immunity, suggesting that uILC2s could be important during pregnancy. Accordingly, I found that lack of uILC2s leads to insufficient spiral artery remodelling and restricted foetal growth. Type-2 cytokines and in particular IL-4 regulates alternative activation of Macrophages (Mac) and Dendritic Cells (DCs), which promote the development of an anti-inflammatory environment and facilitate tissue remodelling. I hypothesised that similar mechanisms occur in the uterus and that uILC2s have a central role in the polarisation of the immune response. To explore this, I studied in more detail the characteristics of uEo, uMac, and uDCs dissected from wild type and ILC2KO mice. I found a reduction in genes associated with alternative activation in uMac and uDCs in the uterus of pregnant ILC2KO mice. Additionally, I showed that uEo are the main producers of the IL-4. This demonstrates that uILC2s promote alternative activation of myeloid cell population by modulating the uterine immune microenvironment. I then assessed the role of uILC2s-dependent type-2 immunity in inflammatory pathology following a type-1 response to bacterial infection. When challenged with LPS, pregnant ILC2KO mice showed more pronounced foetal demise. Therefore, uILC2s regulate uterine type-2 immune homeostasis and this prevents inflammatory pathology. Collectively, my work advances our knowledge of the innate immune mechanisms that control physiological and pathological events during pregnancy. These findings have implications to the field of immunology of pregnancy and may lead to clinical progress in diagnosis and prevention of infection-induced abortion in human pregnancies.

The proper regulation of inducible costimulator (ICOS) and its ligand (ICOSL) have been shown to be essential for maintaining immune homeostasis. Loss of either protein results in defective humoral immunity, and overexpression of ICOS results in aberrant antibody production resembling lupus. How ICOSL is regulated in response to ICOS interaction is still unclear. We demonstrate that ADAM10 is the primary physiological sheddase of ICOSL in both mouse and human. Using an in vivo system in which ADAM10 is deleted only on B cells (ADAM10B-/-), elevated levels of ICOSL were seen. This increase is also seen when ADAM10 is deleted from human B cell lines. Identification of the primary sheddase has allowed the characterization of a novel mechanism of ICOS regulation. In wildtype (WT) mice, interaction of ICOSL/ICOS results in ADAM10 induced shedding of ICOSL on B cells and moderate ICOS internalization on T cells. When this shedding is blocked, excessive ICOS internalization occurs. This results in severe defects in T follicular helper (TFH) development and Th2 polarization, seen in a house dust mite exposure model. In addition, enhanced Th1 and Th1 immune responses are seen in experimental allergic encephalomyelitis. Blockade of ICOSL rescues T cell ICOS surface expression and at least partially rescues both TFH numbers and the abnormal antibody production previously reported in these mice. Overall, we propose a novel regulation of the ICOS:ICOSL axis, with ADAM10 playing a direct role in regulating ICOSL as well as indirectly regulating ICOS, thus controlling ICOS:ICOSL-dependent responses. Additionally, we report a specific role for the metalloprotease ADAM10 on B cells in regulating both ICOSL and ICOS in a mouse model of increased humoral immunity using mir146a-/- mice and a model of lymphoproliferative disease using the well characterized lpr model. B6lpr mice lacking ADAM10 on B cells (A10Blpr) have decreased nodal proliferation and T cell accumulation compared to control B6lpr mice. Additionally, A10Blpr mice have a drastic reduction in autoimmune anti-dsDNA antibody production. In line with this, we found a significant reduction in follicular helper T cells (TFH) and germinal center (GC) B cells in these mice. We also show that lymphoproliferation in this model is closely tied to elevated ICOS levels and decreased ICOSL levels. Overall, our data not only shows a role of B cell ADAM10 in controlling autoimmunity, but also increases our understanding of the regulation of ICOS and ICOSL in the context of autoimmunity. Additionally, we found that ADAM17 is important for marginal zone (MZ) B cell development as well as responses to T-independent type 2 (TI2) immunizations. Mice which lack ADAM17 on B cells (A17B) have decreased MZ B cell numbers but have increased levels of antigen specific antibodies in response to TI2 Immunizations. ADAM17 also regulates the level of several surface molecules on plasma cells and MZ B cells necessary for their function and survival. We also show a role for ADAM17 in ILC2 responsiveness to IL-33. In vivo, mice that lack ADAM17 specifically on ILC2s (ADAM17ILC2-/-) exhibit decreased ILC2 expansion in response to intranasal IL-33 as well as Nippostrongylus brasiliensis (Nb) infection. However, ADAM17ILC2-/- mice have normal ILC2 numbers in a naïve state, suggesting this defect in ILC2 function is limited to cell activation. In vitro, ADAM17 inhibited ILC2s have an increased level of apoptosis and less IL-13 production in response to IL-33 compared to vehicle treated ILC2s. The defect in cytokine production following ADAM17 inhibition is not observed in response to IL-25 stimulation, suggesting this defect is limited to IL-33 stimulation Mechanistically, ADAM17 inhibition in ILC2s specifically causes a defect in IL-33 mediated ERK activation, potentially explaining the defective survival and IL-13 production following ADAM17 inhibition in these cells. Additionally, ADAM17 regulates the level of surface IL1R2 which may affect IL-33 signaling in ILC2s.

Des études menées au laboratoire avaient démontré un rôle critique de l’inflammasome NLRP3 dans l’asthme allergique en réponse à l’ovalbumine en absence d’adjuvant. Mes travaux de thèse ont porté sur le rôle de NLRP3 et de la caspase-1 dans un modèle murin d’inflammation pulmonaire induite par l’allergène d’acarien HDM. Nous avons montré un rôle régulateur de la caspase-1 dépendant de l’inflammasome NLRP3 et la molécule adaptatrice ASC mais pas de l’inflammasome NLRC4. Cette régulation de la réponse allergique se caractérise par une augmentation de l’infiltration des éosinophiles, de l’hyperréactivité bronchique et de la production des cytokines de type Th2 telles que l’IL-4, l’IL-5, l’IL-13 et l’IL-33 dans les poumons. Nous avons montré que les mécanismes responsables de cette régulation sont associés à l’IL-33 produite par les macrophages et que la neutralisation de l’IL-33 par administration locale de la protéine de fusion au récepteur ST2 (muST2-Fc) atténue les caractéristiques de l’asthme allergique. Ces résultats suggèrent que l’activation de la caspase-1 réduit la production d’IL-33 in vivo et régule ainsi la réponse l’inflammation pulmonaire induite par HDM et la réponse Th2. D’autre part, nous nous sommes intéressés au rôle de la Protéine Kinase C thêta (PKC-θ) dans ce même modèle d’inflammation pulmonaire. Nous avons démontré que PKC-θ joue non seulement un rôle protecteur dans l’asthme allergique mais également un rôle critique pour la prolifération et l’activation des cellules lymphoïdes innées (ILC2). D’autre part, l’inhibition de PKC-θ in vivo par administration orale de son inhibiteur spécifique C20 (BIX02656) atténue l’inflammation pulmonaire et la production d’IL-5 et d’IL-13. Nous suggérons que PKC-θ est impliquée dans la différenciation des Th2 et des ILC2 via un mécanisme dépendant des facteurs de transcription IRF4 et NFAT-1. Au total, mes travaux de thèse mettent en exergue deux molécules IL-33 et PKC-θ qui pourraient constituer des cibles thérapeutiques potentielles. / Studies from our laboratory have shown a critical role of NLRP3 inflammasome in response to ovalbumin allergen. In the present study we investigate the role of NLRP3 and caspase-1 in a mouse model of pulmonary inflammation induced by HDM. We have shown a regulatory role of caspase-1 dependant of the NLRP3 inflammasome and the adaptator molecule ASC but not NLRC4. The regulation of the allergic response is characterized by an increase of eosinophilia, bronchial hyperreactivity and Th2 cytokines production (IL-4, IL-5, IL-13 and IL-33) in lungs. We have shown that mechanisms responsible of this regulation are associated with IL-33 production by macrophages and that neutralization of IL-33 by local administration of a fusion protein of the ST2 receptor (muST2-Fc) reduce characteristics of asthma. These results suggest that caspase-1 activation reduce IL-33 production in vivo regulating lung inflammation and Th2 response induced by HDM. Moreover, we investigate the role of the Protein Kinase C theta (PKC-θ) in allergic airway inflammation. We have demonstrated that PKC-θ plays a protective role in allergic asthma but is critical for the activation and proliferation of innate lymphoid cells (ILC2). In addition, in vivo inhibition by oral administration of PKC-θ specific inhibitor C20 (BIX02656) reduces pulmonary inflammation with IL-5 and IL-13 production. We suggest that PKC-θ is implicated in Th2 and ILC2 differenciation by a mechanism dependant on transcription factors IRF4 and NFAT-1. Finally, my thesis projects describe IL-33 and PKC-θ as potential therapeutic targets for allergic lung inflammation.

付記する学位プログラム名: 京都大学卓越大学院プログラム「メディカルイノベーション大学院プログラム」 / 京都大学 / 新制・課程博士 / 博士(薬科学) / 甲第24547号 / 薬科博第164号 / 新制||薬科||18(附属図書館) / 京都大学大学院薬学研究科薬科学専攻 / (主査)教授 生田 宏一, 教授 橋口 隆生, 教授 木村 郁夫 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM

Introduction: Atopic dermatitis (AD) is characterized by chronic pruritic relapsing eczematous lesions of the skin. Eosinophilic inflammation in AD is driven by activation of type 2 inflammatory cells including CD4+ T cells and type 2 innate lymphoid cells (ILC2s). We have shown that type 2 cytokines, namely interleukin (IL)-5 and IL-13, stimulate migration and terminal differentiation of eosinophil progenitor cells (EoPs). We propose that these cytokines are important drivers of tissue eosinophilia in AD lesional skin. This study aimed to quantify, by flow cytometry, cells that produce type 2 cytokines in lesional skin compared to peripheral blood from moderate-severe AD patients. Methods: In a cross-sectional study of patients with moderate-to-severe AD (n=16), type 2 inflammatory cells were enumerated in blood and cells extracted from excised skin biopsies. By flow cytometry, live, singlet CD45+cells were identified as ILC2 (lin-CD127+CD294+), EoP (CD34+125+), and CD4+ T cells (Lin+CD3+CD4+). Intracellular expression of type 2 cytokines (IL-5 and IL-13) were evaluated in each cell population. In addition, we developed a protocol to enumerate ILC2s by fluorescence immune-histochemistry in lesional versus non-lesional skin samples and skin biopsies taken 24h post-intradermal challenge with allergen versus diluent. Data are expressed as median (interquartile range [IQR]) unless otherwise stated. Cross compartmental comparisons were made using the Wilcoxon rank-sum test and where applicable, correlational analyses were performed using a Spearman’s rank-correlational test. Results: There was a significantly higher number of total ILC2s in lesional skin compared to blood from AD subjects (556 [99 – 5501] vs 235 [67 – 569] cells/mL, p=0.03). Similarly, IL-5+, IL-13+ ILC2s, were significantly greater in skin compared to blood (6 [1 – 666] vs 1 [1 – 19] cells/mL, p=0.03; 28 [1 – 1357] vs 1 [1 – 7] cells/mL, p=0.01, respectively). We found higher numbers of total and type 2 cytokine positive EoP in lesional skin biopsies from AD patients compared to blood (Total EoP: 815 [285 – 2794] vs 112 [46 – 247] cells/mL, p<0.01; IL-5+EoP: 36 [1 – 129] vs 1 [1 – 23] cells/mL, p=0.07; IL-13+EoP: 92 [10 – 182] vs 1 [1 – 8] cells/mL, p<0.01 and IL-5+IL-13+ILC2: 70 [1 – 158] vs 1 [1 – 12] cells/mL, p=0.02, respectively). In contrast, significantly higher numbers of total and type 2 cytokine positive CD4+ cells were found in blood compared to lesional skin biopsies from AD patients (Total CD4+: 1092 [650 – 1742] vs 58.3 [35.3– 152.4] x 103 cells/mL, p<0.01 and IL-5+IL-13+CD4+ cells: 13.5 x 103 [2.1 x 103 – 42.9 x 103] vs 3.8 x 103 [1.6 x 103 – 4.9 x 103] cells/mL, p=0.02, respectively). For IF staining, there was a significant higher number of ILC2s in lesional compared to non-lesional skin biopsies and biopsies taken 24h post allergen- compared to diluent challenge (1 [0 – 2] vs 0 [0 - 0] cells/mm2, p=0.008, and 2 [1 – 2] vs 0 [0 – 0] cells/mm2, p=0.0002, respectively). Interestingly, in sex analyses we found significantly greater levels of blood ILC2 in females compared to males, but this not was found in the skin. Importantly, we found a significant correlation between lesional skin levels of ILC2 measured by flow cytometry and clinical measures of disease severity/symptoms as reported/calculated from the Patient-Oriented Eczema Measure questionnaire (POEM) score (total ILC2: r=0.55, p=0.04; IL-13+ ILC2s, r=0.61, p=0.02 and IL-5+ IL-13+ ILC2s: r=0.75, p=0.002). Conclusions: Preferential increases in skin-resident ILC2 that produce a type 2 rich environment were found in AD subjects. These levels correlated with patient-oriented measure of disease severity. We propose that this increase may encourage recruitment of mature eosinophils and EoP and possibly drive localized differentiation of EoP into mature eosinophils that may drive the pathology of AD lesions. Furthermore, immunofluorescence staining may be a suitable alternative to flow cytometry for identification of ILC2 in the event of a low cell count. These techniques can be used in future studies that target ILC2 biology to fully understand the role of these cells in driving AD. / Thesis / Master of Science (MSc)

Pour beaucoup d’entre nous, y compris pour de nombreux immunologistes, le rôle du système immunitaire est restreint à un rôle de défense contre différents pathogènes, tels que les bactéries et les virus. Pourtant, il devient de plus en plus incontestable que le système immunitaire est impliqué dans de nombreux autres phénomènes que peuvent être le cancer, l’obésité et la réparation tissulaire. Au cours de cette thèse, nous nous sommes intéressés à l’implication des cellules immunitaires, et plus particulièrement des cellules immunitaires innées, dans le mécanisme de réparation tissulaire. Par la suite, nous avons approfondi ce travail en nous focalisant sur les dérégulations de la réparation tissulaire. Ces dérégulations peuvent donner lieu notamment à des phénomènes de « sur-réparation » telle que la fibrose. La fibrose est définie comme un dépôt excessif de matrice extracellulaire par les fibroblastes en réponse à des molécules profibrotiques tels que le TGFβ ou l’IL-13. Nous nous sommes donc intéressés au rôle de la réponse immunitaire innée dans la fibrose en nous concentrant sur deux types de cellules immunitaires innées : les macrophages et les cellules lymphoïdes innées de type 2 (type 2 innate lymphoïde cells, ou « ILC2 »). Nous avons choisi comme modèle d’étude la sclérodermie systémique, maladie auto-immune caractérisée principalement par la fibrose pouvant toucher la peau et/ou les organes internes. Outre la fibrose, cette pathologie est également associée à des anomalies vasculaires et immunitaires. Les mécanismes liant ces trois caractéristiques sont encore mal définis et mal connus. Il est donc nécessaire de comprendre la physiopathologie de cette maladie et d’établir précisément l’implication de la réponse immunitaire dans la fibrose afin d’offrir un traitement thérapeutique pour les patients sclérodermiques et plus généralement pour toutes les maladies fibrotiques. Dans un premier temps, nous montrons, en cytométrie de flux, une diminution des ILC2 dans le sang des patients sclérodermiques par rapport aux témoins (0,007 ± 0,007% vs. 0,01 ± 0,01%, p=0,001). Chez les sujets sclérodermiques, cette baisse de la fréquence des ILC2 circulantes est inversement corrélée à l’atteinte de la fibrose cutanée définie par le score de Rodnan (R=-0,35, p=0,0062). Nous observons une augmentation de ces cellules dans la peau sclérodermique comparé à celle des contrôles (5,015 ± 2,8% vs. 2,816 ± 1,8%). Ce résultat est positivement corrélé au score de Rodnan (r=0,58, p=0,01). Nous obtenons des résultats similaires en immunofluorescence. Un phénotypage des ILC2 dermales nous a permis d’observer une diminution de l’expression de KLRG1 dans la peau des malades. En collaboration avec l’équipe du Pr. Batteux, nous avons étudié le rôle des ILC2 dans un modèle murin de sclérodermie. Nous observons une augmentation cutanée des ILC2 et cela même avant l’établissement de la fibrose au niveau de la peau des souris sclérodermiques (16677 ± 3068 vs. 9091 ± 474). Puis, nous montrons, in vitro, que les ILC2 stimulées par le TGFb perdent l’expression de KLRG1. Au contact des ILC2 stimulées par le TGFb, les fibroblastes deviennent pro-fibrotique en comparaison à l’incubation avec des ILC2 non stimulées. Ces résultats apportent de nouvelles connaissances dans la physiopathologie de la sclérodermie systémique et plus particulièrement dans la fibrose caractérisant cette maladie, ce qui offre des perspectives thérapeutiques potentielles. L’approche conceptuelle du rôle du système immunitaire dans la réparation tissulaire proposée dans cette thèse renouvelle notre vision de l’immunité et ouvre potentiellement un nouveau champ, encore sous-estimé, de thérapies ciblant le système immunitaire. / For many of us, including many immunologists, the role of the immune system is limited to a defense role against different pathogens such as bacteria and viruses. Yet it is becoming increasingly clear that the immune system is involved in many other phenomena such as cancer, obesity and tissue repair.During this thesis, we were interested in the involvement of immune cells, and more particularly innate immune cells, in the tissue repair mechanism. Subsequently, we deepened this work by focusing on the deregulations of tissue repair. These deregulations can lead to "over-repair" phenomena such as fibrosis. Fibrosis is defined as an excessive deposition of extracellular matrix by fibroblasts in response to profibrotic molecules such as TGFβ or IL-13. We therefore focused on the role of the innate immune response in fibrosis by focusing on two types of innate immune cells macrophages and innate lymphoid cells of type 2 (ILC2). We chose systemic scleroderma, an autoimmune disease characterized mainly by fibrosis that can affect the skin and/or internal organs, as our study model. In addition to fibrosis, this pathology is also associated with vascular and immune abnormalities. The mechanisms linking these three characteristics are still poorly defined and poorly understood.It is necessary to understand the physiopathology of this disease and to establish precisely the involvement of the immune response in fibrosis in order to offer therapeutic treatment for scleroderma patients and more generally for all fibrotic diseases.First, we show, in flow cytometry, a decrease of ILC2 in the blood of scleroderma patients compared to controls (0.007 ± 0.007% vs. 0.01 ± 0.01%, p=0.001). In scleroderma subjects, this decrease in the frequency of circulating ILC2 is inversely correlated with skin fibrosis defined by Rodnan's score (R=-0.35, p=0.0062). We observe an increase in these cells in the scleroderma skin compared to controls (5.015 ± 2.8% vs. 2.816 ± 1.8%). This result is positively correlated to Rodnan's score (r=0.58, p=0.01). We obtain similar results in immunofluorescence. In collaboration with Prof. Batteux's team, we studied the role of ILC2 in a mouse model of scleroderma. We observe an increase in cutaneous ILC2 even before fibrosis is established in the skin of scleroderma mice (16677 ± 3068 vs. 9091 ± 474). Then, we show, in vitro, that ILC2 stimulated by TGFb lose the expression of KLRG1. Upon contact with TGFb-stimulated ILC2, fibroblasts become pro-fibrotic compared to incubation with unstimulated ILC2.These results bring new knowledge in the physiopathology of systemic scleroderma and more particularly in the fibrosis characterizing this disease, which offers potential therapeutic prospects.The conceptual approach to the role of the immune system in tissue repair proposed in this thesis renews our vision of immunity and potentially opens up a new and still underestimated field of therapies targeting the immune system.STAR

The Tec kinase ITK is activated by TCR stimulation and also required for TCR downstream signaling. Previous studies have reported differential roles of ITK and another Tec family kinase RLK in CD4+ TH differentiation and effector function. However, these findings are confounded by the complex T cell developmental defects in Itk-/- mice. Furthermore, the function of ITK in tissue-resident T cells in the intestine and anti-viral immune response to a persistent infection has not been studied previously. In addition to T cells, recent studies have indicated an expression of ITK in ILC2, but not in other ILC subsets. Yet, the role of ITK in ILC2 has not been characterized. Here, I have examined the role of ITK and RLK in CD4+ TH subsets using a small molecule inhibitor PRN694. I found that PRN694 impaired TH1 differentiation in vitro, and PRN694 administration prevented TH1-mediated colitis progression in vivo. In an MHV68 infection model, Itk-/- mice failed to control viral replication in the intestine, while gut-homing of CD8+ T cells was greatly impaired. Finally, I found that ILC2 number was markedly reduced in the intestine of Itk-/- mice. Gut-specific defect of Itk-/- ILC2 is associated with a low availability of IL-2 in the intestine of Itk-/- mice. Collectively, these data suggest that ITK is important in T cell migration to the intestine and ILC2 homeostasis in the intestine, thereby contributing to the protective response to a latent virus and intestinal tissue homeostasis.