Parkinson’s disease (PD) is a multi-organ disorder. It is diagnosed from motor impairments that arise from neurodegeneration in the midbrain. However, the disease begins decades earlier in the gut prior to involvement of the brain. PD is characterized by persistent inflammation, both in the brain and in the periphery in addition to neurodegeneration. Here, I investigate the role of the adaptive immune system in disease pathogenesis and as a driver of prodromal symptoms of PD in both humans and mice. In Chapter 1, I introduce Parkinson’s disease, its pathological hallmarks and the progression of the symptoms, and discuss genetic and environmental influences. Then, I elaborate on the inflammatory phenotypes observed in the disease and recent work describing the role of inflammation in animal models for PD. In Chapter 2, I examine the autoimmune features of Parkinson’s disease from analysis of patients’ blood. I found that approximately 40% of PD patients possess aspects of autoimmunity against α-synuclein. By screening peripheral blood mononuclear cells of patients and healthy controls for potential neoantigens derived from α-synuclein protein, I identified two antigenic regions of the protein that elicit an immune response. The immune responses to a specific α-synuclein neo-antigens were linked to unique HLAs that are over-represented in our PD cohort and are associated with PD in genome wide association studies (GWAS). In Chapters 3 and 4, I describe the effects of recapitulating α-synuclein autoimmunity in a humanized mouse strain expressing the HLA allele risk for PD. In Chapter 3, I show that the humoral and cellular immunity is mounted against α-synuclein in the humanized mice, similar to what is observed in PD patients; however, there is no inflammation or immune response toward the brain. In Chapter 4, I show how the autoimmune response to α-synuclein induces inflammation and neurodegeneration in the gut leading to constipation in mice, recapitulating the prodromal aspects of the human disease. Finally, in Chapter 5, I discuss the implications of these findings for α-synuclein autoimmunity in the periphery, gut and brain in Parkinson’s disease. I also elaborate on the implications of these findings for potential future diagnostic screening and treatments for Parkinson’s disease.

TSSP (Protéase à Sérine Spécifique du Thymus) est une protéase exprimée de manière prépondérante dans le thymus par les cellules épithéliales thymiques corticales (cTEC) et par les cellules dendritiques thymiques (tDC). En revanche, TSSP n'est pas exprimée par les cellules dendritiques (DC) en périphérie même après activation par des agonistes de TLR (Toll-like Receptor). L'équipe a précédemment montré que les souris NOD déficientes pour TSSP (NOD TSSP°) sont totalement résistantes au développement du diabète de type 1 (T1D) contrairement aux souris NOD WT qui développent de manière spontanée la pathologie. L'absence de T1D est due à une augmentation de la sélection négative de cellules T CD4 spécifiques de certains antigènes des ilots de Langerhans par les tDC. Ainsi, la déficience en TSSP conduit à l'épuration du répertoire des cellules T CD4 auto-réactifs par des évènements de sélection négative dans le thymus limitant ainsi le développement du T1D. Bien que la fonction précise de TSSP reste inconnue, ces données et des données complémentaires montrent que TSSP dans les tDC limite la présentation de certains antigènes des ilots de Langerhans dans la voie classe II. Nous avons, dans un premier temps, déterminé si le rôle de TSSP peut être généralisé à une autre maladie auto-immune médiée également par les cellules T CD4, l'encéphalomyélite auto-immune expérimentale (EAE), un modèle murin de sclérose en plaque. Nous avons montré que la sévérité de l’EAE induite par immunisation avec le peptide MOG35-55 (Glycoprotéine de l'Oligodendrocyte de la Myéline) est réduite chez les souris NOD TSSP°. La réduction de sévérité chez les souris NOD TSSP° est associée à une augmentation de la délétion des cellules T CD4 spécifiques du peptide MOG35-55. TSSP limiterait la délétion thymique des cellules T CD4 spécifiques de MOG35-55. Ainsi TSSP, en réduisant le répertoire peptidique présenté par les molécules I-Ag7, conduirait à un défaut de tolérance centrale favorisant le développement de maladies auto-immunes. Dans un second temps, l’objectif de mes travaux de thèse a été d'apporter de nouvelles connaissances quant à la fonction de TSSP dans les tDC. L’ensemble des données suggèrent que TSSP limiterait la présentation d’antigènes dans la voie classe II, nous avons donc analysé les capacités d’internalisation et de dégradation des tDC par imagerie en flux. Nous avons montré que TSSP limite spécifiquement l'internalisation de la protéine ovalbumine dans les cellules dendritiques conventionnelles 2 (cDC2) et dans une lignée de DC mais n'affecte pas leurs capacités dégradatives. De plus, la réduction de l’internalisation des antigènes dans les tDC de souris NOD WT est indépendant de l’endocytose médiée par récepteur. Ces données suggèrent que TSSP en réduisant l'internalisation des antigènes pourrait limiter la formation de complexes peptide/CMH II et la présentation antigénique dans la voie classe II. Par ce mécanisme, TSSP induirait un défaut de tolérance centrale et favoriserait le développement de maladies auto-immunes. / TSSP (Thymus Specific Serine Protease) is a protease expressed predominantly in the thymus by thymic epithelial cortical cells (cTEC) and thymic dendritic cells (tDC). In contrast, TSSP is not expressed by dendritic cells (DC) in the periphery even after activation by TLR agonists (Toll-like Receptor). Previous studies showed that TSSP-deficient NOD mice are completely resistant to the development of type 1 diabetes (TD1) whereas NOD WT mice spontaneously develop pathology. The absence of T1D is due to an increase in the negative selection, by tDC, of CD4 T cells specific for certain antigens of the islets of Langerhans. Thus, TSSP deficiency leads to the crippling of the autoreactive CD4 T cells repertoire by negative selection in the thymus limiting the development of T1D. Although the precise function of TSSP remains unknown, these data and complementary data show that TSSP in tDC limits the presentation of certain islet antigens in the class II pathway. At first, the aim of my PhD work was to determine if the role of TSSP can be generalized to another autoimmune disease also mediated by CD4 T cells, experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. We have shown that the severity of EAE induced by immunization with MOG35-55 (Myelin Oligodendrocyte Glycoprotein) peptide is reduced in NOD TSSP° mice. Reduced disease severity is linked to increased deletion of MOG35-55 specific CD4 T cells in TSSP-deficient NOD mice. TSSP would limit the thymic deletion of MOG35-55 specific CD4 T cells. Thus, by reducing the peptide repertoire presented by the IAg7 molecules, TSSP would limit central tolerance and favor the development of autoimmune diseases. In continuation, the second objective of my thesis work was to clarify the function of TSSP in tDC. Given the suspected role of TSSP in the class II pathway we analyzed the internalization and degradation capabilities of tDCs by flow imaging. We have shown that TSSP specifically limits the internalization of ovalbumin protein in conventional dendritic cells 2 (cDC2) and in a DC line but does not affect the degradation of endocytosed OVA. The reduction of antigens internalization in the tDC of NOD WT mice is independent of receptor-mediated endocytosis. These data suggest that, by reducing internalization of antigens, TSSP could limit the formation of peptide/MHC II complexes and antigenic presentation in the class II pathway. By this mechanism, TSSP induces a defect of central tolerance and promotes the development of autoimmune diseases

Next generation sequencing, which allows concurrent parallel sequencing of many samples and makes it possible to distinguish the infection from multiple viral types in the sample, is well suited as a detection format for such assays described below. The aim of the thesis was to develop a method that could detect all known types of human adenoviruses, human enteroviruses, and bacteriophages selected for their presence in the intestine. Using the next- generation sequencing. The first step was to design primers capable of detecting all known types of viruses, covering the area that is capable of distinguishing these viruses. This method was tested on a set of 47 human adenovirus samples and 30 human enterovirus samples of known serotype. Samples with two serotypes in different proportions were also created. After amplification of the target genome, the samples were purified and sequenced on MiSeq, Illumina. The method was further used in the typing of adenoviruses, enteroviruses and bacteriophages in pre-diabetic cohorts of DIPP, MIDIA, and a cohort of diabetics from African and Asian countries. The tested sample was RNA / DNA isolated from the stool specimen. We have demonstrated that the method is capable to detect all tested virus types, including infections with two different types, even if the...

Type 1 Diabetes (T1D) is a complex autoimmune disorder in which T cells destroy the pancreatic islets, leading to a loss of insulin production and hyperglycemia. The disease incidence has increased globally over the last decades, primarily in individuals with low to moderate genetic risk. There is evidence that environmental factors play a role alongside genetic risk to trigger the disease. An environmental factor that has global influence is adoption of the Western diet, characterized by increased consumption of n-6 fatty acids, including linoleic acid (LA), and decreased consumption of n-3 fatty acids. Increased n-6/n-3 ratios are associated with enhanced susceptibility to autoimmune diseases. We sought to understand how linoleic acid affects the survival and function of T cells from the non-obese diabetic (NOD) mouse, a model for T1D. We found that linoleic acid's presence during in vitro activation of T cells led to an increased expansion of the cells in culture. Additionally, CD4+ and CD8+ T cells activated in linoleic acid's presence produced increased levels of pro-diabetogenic cytokines, including Interleukin-21 (IL-21) and Interferon-gamma (IFN-γ). In contrast, linoleic acid reduced IL-10-producing CD4+ T cells, which are protective in T1D, significantly changing the balance between pro-and anti-inflammatory T cell subsets. Gene expression analysis of T cells exposed to linoleic acid during in vitro activation revealed decreased gene expression of lipid-regulated transcription factors, peroxisome proliferator-activated receptors (PPAR), PPARα and PPARγ. These data suggest a role for these transcription factors and their associated pathways in linoleic acid-mediated T cell functions. Finally, we tested whether the T cell fatty acid response is regulated by the cytokine IL-7, which modulates T cell immunometabolism. However, our data did not reveal a prominent role for IL-7 in regulating the T cell response to linoleic acid. Together, these studies add to evidence that fatty acids present in the microenvironment can directly alter T cell functions and that changes in dietary components may contribute to enhanced T1D susceptibility.

Mucopolysaccharidosis (MPS) IIIB is a lysosomal storage disease with severe neurological manifestations due to a-N-acetylglucosaminidase (NaGlu) deficiency. The mechanism of neuropathology in MPS IIIB is unclear. This study investigates the role of immune responses in neurological disease of MPS IIIB in mice. By means of gene expression microarrays and realtime quantitative reverse transcriptase-polymerase chain reaction, we demonstrated significant up-regulation of numerous immune-related genes in MPS IIIB mouse brain involving a broad range of immune cells and molecules, including T cells, B cells, microglia/ macrophages, complement, major histocompatibility complex class I, immunoglobulin, Toll-like receptors, and molecules essential for antigen presentation. The significantly enlarged spleen and lymph nodes in MPS IIIB mice were due to an increase in splenocytes/lymphocytes, and functional assays indicated that the T cells were activated. An autoimmune component to the disease was further suggested by the presence of putative autoantigen or autoantigens in brain extracts that reacted specifically with serum IgG from MPS IIIB mice. We also demonstrated for the first time that immunosuppression with prednisolone alone can significantly slow the central nervous system disease progression. Our data indicate that immune responses contribute greatly to the neuropathology of MPS IIIB and should be considered as an adjunct treatment in future therapeutic developments for optimal therapeutic effect.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18677号 / 医博第3949号 / 新制||医||1007(附属図書館) / 31610 / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙折 晃史, 教授 長田 重一, 教授 河本 宏 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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At the intersection between autoimmune disease and cancer lies a disruption in the balance of our body’s critically important immune system, and, specifically, in its regulation. While autoimmune diseases are the result of overactivation and a failure to regulate improper responses to the body’s own tissues, cancer is the result of improper suppression and a failure to recognize and eradicate transformed malignant cells. Although they are fundamentally different conditions, overlap can be found in the pathways which are critical to disease progression and which may represent important therapeutic targets. One such pathway implicated in both autoimmunity and cancer is the aryl hydrocarbon receptor (AhR). AhR activation suppresses immune cell activation through the modulation of T cell differentiation and antigen presenting cell (APC) function. AhR activation shows a beneficial therapeutic effect in models of autoimmune disease, but has also been implicated in driving cancer progression and tumor-mediated immunosuppression. While it is clear that the AhR plays an important role in the immune response, the mechanisms behind AhR regulation of the immune system and the effects of its modulation in autoimmunity and cancer are still not fully understood. Thus, in this work, we investigated the effect of targeting the AhR in models of autoimmunity and cancer, using the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS) and the murine oral cancer (MOC) model of oral squamous cell carcinoma (OSCC). We demonstrated that AhR activation using the endogenous ligand 2-(1’H-indole-3’-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) induced a tolerogenic transcriptional response in mouse and human dendritic cells (DCs) associated with the induction of immunoregulatory/immunosuppressive mechanisms. We further showed that targeting the AhR using a nanoliposome (NLP) delivery platform, which co-encapsulated a MS autoantigen, suppressed the development of EAE in multiple models, both in preventative and therapeutic contexts. This disease suppression was associated with the expansion of antigen-specific FoxP3+ regulatory T cells (Treg cells) and IL10+ type 1 regulatory T cells (Tr1 cells), and a reduction in CNS-infiltrating effector T cells (Teff cells). Using the MOC1 model of OSCC we demonstrated that deletion of the AhR in MOC1 malignant cells completely blocks in vivo tumor growth in an immune system-dependent manner and renders mice completely immune to either local or systemic re-challenge with wildtype MOC1 cells. Suppression of tumor growth was associated with a decrease in the expression of suppressive immune checkpoint markers including PD-L1 and CD39 on macrophages, dendritic cells, and Ly6G+ myeloid cells, and PD-1, CTLA4, Lag3, and CD39 on CD4+ T cells. Further, the AhR was found to control expression of chemokines and immunosuppressive IDO and PD-L1 in malignant cells themselves, suggesting that AhR activity in tumor cells may simultaneously regulate multiple immune checkpoints. Taken together, these results provide new insight into the critical role for the AhR in both autoimmunity and cancer, and confirm it as a valid therapeutic target for both diseases. / 2022-03-05T00:00:00Z

A Case Report of Catastrophic Antiphospholipid Syndrome with Libman-Sacks Presenting as Interstitial Pneumonia Chassidy Sumler Martin, MS, Rocco Cannistraro, MD Antiphospholipid syndrome (APS) is an autoimmune condition characterized by vascular thromboses and a positive antiphospholipid antibody. Catastrophic antiphospholipid syndrome (CAPS) is a rare disease that often results in death. CAPS is the most severe form of APS, which can develop in a short period of time and occurs in less than 1% of people with APS. CAPS involves multiple organs simultaneously with diffuse microvascular and macrovascular involvement. Here, we present a case of catastrophic antiphospholipid syndrome presenting as interstitial pneumonia that rapidly progressed to acute renal failure, acute ischemic cerebral infarcts, cardiac valvular vegetations, and heart failure. This case report aims to bring awareness of prompt medical suspicion and treatment of CAPS in hopes of improving disease outcomes.

No description available.