Type 1 diabetes (T1D) is an autoimmune disease leading to destruction of insulin-secreting pancreatic -cells. Environmental factors e.g. exposures to infections, dietary components play a substantial role in etiopathogenesis of T1D and are responsible for rapid increase of T1D incidence in past decades, preferentially in developed countries. Despite long record of T1D research no causative cure or efficient prevention exists. While gluten displays proinflammatory properties, gluten-free diet (GFD) has been documented by several studies as a strong diabetes- preventive environmental factor in spontaneous animal models of T1D, mostly in NOD mouse. The aim of this thesis is to better characterize effects of GFD on the immune system of NOD mouse. Using flow cytometry, we compared effects of GFD vs standard (STD) Altromin diets on NK cell subsets, Tregs, as well as other regulatory cell subsets and their cytokine profile in prediabetic SPF NOD females that were exposed to the diets since "in utero". A reference diabetes incidence in NOD females in our SPF facility kept on STD and GFD was recorded. Diabetes-preventive capacity of GFD were tested by using the NOD-SCID model of diabetes transfer, in which splenocytes from at-onset NOD females kept on GFD or STD were transferred to NOD-SCID recipients....

Over the last decade, advancements in connectivity, driving automation technology and electrificationin combination with changing customer demands have started to rapidly transform the way in whichgoods are being transported. Following this fast rate of development, self-driving vehicles (SDVs) inroad freight transport are anticipated to operate on public streets within the next couple of decades. The road freight transport sector is particularly feasible and attractive for driving automationtechnology. In this sector, there are strong economic incentives and rationales to implement SDVs inroad freight transport as it presents possibilities to eliminate or drastically reduce driver costs,optimize vehicle usage rates and improve energy efficiency. Widespread adoption of SDVs isespecially feasible for so called node-to-node freight transport flows, carried out between importantlogistics hubs. Node-to-node road freight transport is characterised by repetitive and predictive flowsof goods, conducted in less complex driving environments such as highways and industrial areas. Although SDVs are predicted to bring significant impacts to the transport system and society,research on the potential influence of commercial use cases of SDVs in road freight transport is scarce.Research aiming to provide an overview of how different type of actors are involved in shaping thedevelopment, deployment and future operations of SDVs in road freight transport is also limited. This paper provides an understanding of system-level impacts of SDVs in node-to-node road freighttransportation. It also provides a synthesized view of opportunities and barriers that actors are facingin relation to a large scale use of SDVs in road freight transport. This understanding makes it possiblefor stakeholders to identify expectations, needs, policies and strategies to govern a sustainabletransitions of the transport system. In addition, the paper provides an investigation of requirementsfor new knowledge and competencies along with development. By using technical innovation systems (TIS) as a theoretical approach for the study, differentcomponents and aspects of the Swedish freight transport system are described and analysed inrelation to SDV development and innovations. The TIS framework consists of a set of systemcomponents involved in the generation, diffusion and utilisation of a technology, and therelationships between the components. TIS components include actors, institutions, and networks,where networks describe the relationships between actors and institutions. In the paper, Sweden isused as case study. The results are based on 19 qualitative interviews with representatives from abroad spectrum of actors all being part of, or expected to be part of, a road freight transport systemwhere SDVs is a central component. By analysing the interview results using the TIS framework, one of the main findings is that the publicsector together with truck manufacturers are key actors in governing and enabling acommercialization of SDVs in road freight transport. Truck manufacturers have a great power inshaping the system by driving the technical development of SDVs, while government agencies areresponsible for regulations and guidelines influencing the direction of development. The results further indicate that the introduction of SDVs in road freight transport would implychanging dynamics between the actors and other components of the TIS. One example is the role ofroad carriers and freight forwarders who are currently two of the most central actors in the freighttransport system. In a transport system with SDVs, those actors may become less influential. Likewise,actors that are currently not having a central role in the freight transport system may become moreinfluential. For instance, SDVs can catalyse a development towards electrification. This is a way ofexpanding the system boundaries and implies that new actors, such as energy companies and fuelretailing companies, begin to investigate how they could develop their business models to become a part of an evolving market. This is important in order to be able to compete and engage in a systemwith SDVs. Another finding is that there is a consensus among interviewed actors that SDVs must be adapted tothe existing road infrastructure system rather than the other way around. At the same time, acompletely new digital infrastructure system is being created around SDVs, which is necessary tohandle the large amounts of data required for SDVs to operate. Furthermore, the connection betweenelectrification and automation is somewhat ambiguous - some claim that there is clear symbiosisbetween the two technologies while others argue that they just happen coincided in time. Finally, the results indicate a lack of holistic and systematic perspectives among the actors on howthe development and deployment of SDVs could contribute to sustainability in the freight transportsystem. It is critical to at this early state of implementation govern and shape technologicaldevelopment and business models in a direction that ensures a sustainable path for a future transportsystem with SDVs. / Under det senaste decenniet har det gjorts flera framsteg inom teknik för självkörande fordon,uppkoppling och elektrifiering. Detta i kombination med nya krav från kunder har påbörjat en storförändring i hur gods transporteras. Utvecklingen går snabbt och inom de närmsta decenniernaförväntas självkörande lastbilar köra på offentliga vägar. Tekniken för självkörande fordon är särskilt attraktiv och lämplig för vägtransportsektorn. I dennasektor finns det starka ekonomiska incitament och grunder för att implementera självkörandelastbilar. Detta eftersom självkörande lastbilar ger möjlighet att eliminera eller drastiskt minskaförarkostnaderna, optimera användningsgraden av fordon och förbättra energieffektiviteten. Enomfattande implementering av självkörande lastbilar är särskilt lämplig för så kallade nod-till-nodgodstransporter. Nod-till-nod godstransporter är i denna rapport definierade som transportflödensom sker mellan större nav i godstransportsystemet och kännetecknas av repetitiva och förutsägbaravaruflöden som bedrivs i mindre komplexa körmiljöer så som motorvägar och industriområden. Trots att självkörande lastbilar förutses få betydande konsekvenser för transportsystemet ochsamhället är forskning om det potentiella inflytandet av kommersiell användning av självkörandelastbilar bristfällig. Forskning som syftar till att ge en överblick över hur olika typer av aktörer ärinblandade i att forma självkörande lastbilars utveckling, utbyggnad och framtida verksamhet är ävenden begränsad. Denna uppsats syftar till att tillhandahålla en förståelse för systemeffekter av självkörande lastbilar inod-till-nod godstransporter. Den syftar vidare till att ge en syntetiserad överblick av de möjligheteroch hinder som olika typer av aktörer står inför i samband med en storskalig användning avsjälvkörande lastbilar. Denna förståelse gör det möjligt för intressenter att identifiera förväntningar,behov, policys och strategier för att styra en hållbar övergång till ett automatiseratgodstransportsystem i samband med att självkörande fordon blir allt vanligare. Dessutom undersöksvilka nya behov av kunskap och kompetens som skapas i samband med utvecklingen. Genom att använda tekniska innovationssystem (TIS) som teoretiskt ramverk för studien beskrivsoch analyseras olika komponenter och aspekter i det svenska godstransportsystemet i relation tillutveckling och innovation av självkörande lastbilar. TIS-ramverket består av en uppsättningsystemkomponenter som är inblandade i generering, diffusion och användande av en teknik samtrelationerna mellan komponenterna. TIS-komponenter inkluderar aktörer, institutioner och nätverk,där nätverk beskriver förhållandena mellan aktörer och institutioner. I uppsatsen används Sverigesom fallstudie. Resultaten baseras på 19 kvalitativa intervjuer med representanter från ett brettspektrum av aktörer som alla ingår i, eller förväntas vara del av ett godstransportsystem därsjälvkörande lastbilar är en central komponent. Genom att analysera intervjuresultaten med hjälp av TIS-ramverket framkommer bland annat attden offentliga sektorn tillsammans med lastbilstillverkare kan ses som nyckelaktörer i styrning ochmöjliggörande av en kommersialisering av självkörande lastbilar. Lastbilstillverkare har storamöjligheter att forma systemet genom att driva den tekniska utvecklingen, medan myndigheterpåverkar utvecklingsriktningen genom att ansvara för regler och riktlinjer. Resultaten visar vidare att ett införande av självkörande lastbilar skulle innebära förändrad dynamikmellan aktörer och andra komponenter i TIS. Ett exempel är transportföretagen och speditörernasroller som för närvarande är två av de mest centrala aktörerna inom godstransportsystemet. I etttransportsystem med självkörande lastbilar kan dessa aktörer bli mindre inflytelserika. På sammasätt kan aktörer som för närvarande inte har en central roll i godstransportsystemet bli merinflytelserika. Självkörande lastbilar kan exempelvis katalysera en utveckling mot elektrifiering. Det här är ett sätt att utöka systemgränserna vilket leder till att nya aktörer, så som energibolag ochdrivmedelsföretag börjar undersöka hur de kan utveckla sina affärsmodeller för att bli en del avmarknaden. Detta är viktigt för att kunna konkurrera och bli delaktiga i ett system med självkörandelastbilar. Ett annat resultat är att det finns en enighet bland intervjuade aktörer om att självkörande lastbilarmåste anpassas till det befintliga väginfrastruktursystemet snarare än tvärtom. Samtidigt skapas etthelt nytt digitalt infrastruktursystem kring de självkörande lastbilarna, vilket är nödvändigt för atthantera de stora mängder data som krävs för att fordonen ska kunna fungera. Dessutom ärkopplingen mellan elektrifiering och automatisering något tvetydig. Vissa hävdar att det finns entydlig symbios mellan de två teknikerna medan andra hävdar att de bara råkar sammanfalla i tiden. Slutligen tyder resultaten på en brist av holistiska och systematiska perspektiv bland aktörerna omhur utvecklingen och användandet av självkörande lastbilar kan bidra till hållbarhet inomgodstransportsystemet. Det är avgörande att i detta tidiga skede av implementeringen styra ochforma den tekniska utvecklingen och affärsmodellerna i en riktning som säkerställer en hållbarutveckling för ett framtida transportsystem med självkörande lastbilar.

Over the last decade, advancements in connectivity, driving automation technology and electrification in combination with changing customer demands have started to rapidly transform the way in which goods are being transported. Following this fast rate of development, self-driving vehicles (SDVs) in road freight transport are anticipated to operate on public streets within the next couple of decades.   The road freight transport sector is particularly feasible and attractive for driving automation technology. In this sector, there are strong economic incentives and rationales to implement SDVs in road freight transport as it presents possibilities to eliminate or drastically reduce driver costs, optimize vehicle usage rates and improve energy efficiency. Widespread adoption of SDVs is especially feasible for so called node-to-node freight transport flows, carried out between important logistics hubs. Node-to-node road freight transport is characterised by repetitive and predictive flows of goods, conducted in less complex driving environments such as highways and industrial areas.   Although SDVs are predicted to bring significant impacts to the transport system and society, research on the potential influence of commercial use cases of SDVs in road freight transport is scarce. Research aiming to provide an overview of how different type of actors are involved in shaping the development, deployment and future operations of SDVs in road freight transport is also limited.   This paper provides an understanding of system-level impacts of SDVs in node-to-node road freight transportation. It also provides a synthesized view of opportunities and barriers that actors are facing in relation to a large scale use of SDVs in road freight transport.  This understanding makes it possible for stakeholders to identify expectations, needs, policies and strategies to govern a sustainable transitions of the transport system. In addition, the paper provides an investigation of requirements for new knowledge and competencies along with development.   By using technical innovation systems (TIS) as a theoretical approach for the study, different components and aspects of the Swedish freight transport system are described and analysed in relation to SDV development and innovations. The TIS framework consists of a set of system components involved in the generation, diffusion and utilisation of a technology, and the relationships between the components. TIS components include actors, institutions, and networks, where networks describe the relationships between actors and institutions.  In the paper, Sweden is used as case study. The results are based on 19 qualitative interviews with representatives from a broad spectrum of actors all being part of, or expected to be part of, a road freight transport system where SDVs is a central component.   By analysing the interview results using the TIS framework, one of the main findings is that the public sector together with truck manufacturers are key actors in governing and enabling a commercialization of SDVs in road freight transport. Truck manufacturers have a great power in shaping the system by driving the technical development of SDVs, while government agencies are responsible for regulations and guidelines influencing the direction of development.   The results further indicate that the introduction of SDVs in road freight transport would imply changing dynamics between the actors and other components of the TIS. One example is the role of road carriers and freight forwarders who are currently two of the most central actors in the freight transport system. In a transport system with SDVs, those actors may become less influential. Likewise, actors that are currently not having a central role in the freight transport system may become more influential. For instance, SDVs can catalyse a development towards electrification. This is a way of expanding the system boundaries and implies that new actors, such as energy companies and fuel retailing companies, begin to investigate how they could develop their business models to become a part of an evolving market. This is important in order to be able to compete and engage in a system with SDVs.   Another finding is that there is a consensus among interviewed actors that SDVs must be adapted to the existing road infrastructure system rather than the other way around. At the same time, a completely new digital infrastructure system is being created around SDVs, which is necessary to handle the large amounts of data required for SDVs to operate. Furthermore, the connection between electrification and automation is somewhat ambiguous - some claim that there is clear symbiosis between the two technologies while others argue that they just happen coincided in time.   Finally, the results indicate a lack of holistic and systematic perspectives among the actors on how the development and deployment of SDVs could contribute to sustainability in the freight transport system. It is critical to at this early state of implementation govern and shape technological development and business models in a direction that ensures a sustainable path for a future transport system with SDVs. / Under det senaste decenniet har det gjorts flera framsteg inom teknik för självkörande fordon, uppkoppling och elektrifiering. Detta i kombination med nya krav från kunder har påbörjat en stor förändring i hur gods transporteras. Utvecklingen går snabbt och inom de närmsta decennierna förväntas självkörande lastbilar köra på offentliga vägar.   Tekniken för självkörande fordon är särskilt attraktiv och lämplig för vägtransportsektorn. I denna sektor finns det starka ekonomiska incitament och grunder för att implementera självkörande lastbilar. Detta eftersom självkörande lastbilar ger möjlighet att eliminera eller drastiskt minska förarkostnaderna, optimera användningsgraden av fordon och förbättra energieffektiviteten. En omfattande implementering av självkörande lastbilar är särskilt lämplig för så kallade nod-till-nod godstransporter. Nod-till-nod godstransporter är i denna rapport definierade som transportflöden som sker mellan större nav i godstransportsystemet och kännetecknas av repetitiva och förutsägbara varuflöden som bedrivs i mindre komplexa körmiljöer så som motorvägar och industriområden.   Trots att självkörande lastbilar förutses få betydande konsekvenser för transportsystemet och samhället är forskning om det potentiella inflytandet av kommersiell användning av självkörande lastbilar bristfällig. Forskning som syftar till att ge en överblick över hur olika typer av aktörer är inblandade i att forma självkörande lastbilars utveckling, utbyggnad och framtida verksamhet är även den begränsad.   Denna uppsats syftar till att tillhandahålla en förståelse för systemeffekter av självkörande lastbilar i nod-till-nod godstransporter. Den syftar vidare till att ge en syntetiserad överblick av de möjligheter och hinder som olika typer av aktörer står inför i samband med en storskalig användning av självkörande lastbilar. Denna förståelse gör det möjligt för intressenter att identifiera förväntningar, behov, policys och strategier för att styra en hållbar övergång till ett automatiserat godstransportsystem i samband med att självkörande fordon blir allt vanligare. Dessutom undersöks vilka nya behov av kunskap och kompetens som skapas i samband med utvecklingen.   Genom att använda tekniska innovationssystem (TIS) som teoretiskt ramverk för studien beskrivs och analyseras olika komponenter och aspekter i det svenska godstransportsystemet i relation till utveckling och innovation av självkörande lastbilar. TIS-ramverket består av en uppsättning systemkomponenter som är inblandade i generering, diffusion och användande av en teknik samt relationerna mellan komponenterna. TIS-komponenter inkluderar aktörer, institutioner och nätverk, där nätverk beskriver förhållandena mellan aktörer och institutioner. I uppsatsen används Sverige som fallstudie. Resultaten baseras på 19 kvalitativa intervjuer med representanter från ett brett spektrum av aktörer som alla ingår i, eller förväntas vara del av ett godstransportsystem där självkörande lastbilar är en central komponent.   Genom att analysera intervjuresultaten med hjälp av TIS-ramverket framkommer bland annat att den offentliga sektorn tillsammans med lastbilstillverkare kan ses som nyckelaktörer i styrning och möjliggörande av en kommersialisering av självkörande lastbilar. Lastbilstillverkare har stora möjligheter att forma systemet genom att driva den tekniska utvecklingen, medan myndigheter påverkar utvecklingsriktningen genom att ansvara för regler och riktlinjer.   Resultaten visar vidare att ett införande av självkörande lastbilar skulle innebära förändrad dynamik mellan aktörer och andra komponenter i TIS. Ett exempel är transportföretagen och speditörernas roller som för närvarande är två av de mest centrala aktörerna inom godstransportsystemet. I ett transportsystem med självkörande lastbilar kan dessa aktörer bli mindre inflytelserika. På samma sätt kan aktörer som för närvarande inte har en central roll i godstransportsystemet bli mer inflytelserika.  Självkörande lastbilar kan exempelvis katalysera en utveckling mot elektrifiering. Det här är ett sätt att utöka systemgränserna vilket leder till att nya aktörer, så som energibolag och drivmedelsföretag börjar undersöka hur de kan utveckla sina affärsmodeller för att bli en del av marknaden. Detta är viktigt för att kunna konkurrera och bli delaktiga i ett system med självkörande lastbilar.   Ett annat resultat är att det finns en enighet bland intervjuade aktörer om att självkörande lastbilar måste anpassas till det befintliga väginfrastruktursystemet snarare än tvärtom. Samtidigt skapas ett helt nytt digitalt infrastruktursystem kring de självkörande lastbilarna, vilket är nödvändigt för att hantera de stora mängder data som krävs för att fordonen ska kunna fungera. Dessutom är kopplingen mellan elektrifiering och automatisering något tvetydig. Vissa hävdar att det finns en tydlig symbios mellan de två teknikerna medan andra hävdar att de bara råkar sammanfalla i tiden.   Slutligen tyder resultaten på en brist av holistiska och systematiska perspektiv bland aktörerna om hur utvecklingen och användandet av självkörande lastbilar kan bidra till hållbarhet inom godstransportsystemet. Det är avgörande att i detta tidiga skede av implementeringen styra och forma den tekniska utvecklingen och affärsmodellerna i en riktning som säkerställer en hållbar utveckling för ett framtida transportsystem med självkörande lastbilar.

Type 1 diabetes mellitus (T1D) is an autoimmune disorder that targets the insulin-producing β-cells. The gut may play a role in the pathogenesis of T1D, as genetically-susceptible individuals and animal models of T1D exhibit increased intestinal permeability and improving gut barrier function can interfere with the onset of diabetes. Moreover gut-derived peptides are capable of modifying barrier function and regulate β-cell mass via effects on proliferation and apoptosis. I tested whether chronic administration of glucagon-like peptide-2 (GLP-2), a peptide which potently improves gut barrier function, modifies diabetes onset in a mouse model of T1D, the non obese diabetic (NOD) mouse. Although chronic treatment with a long-acting GLP-2 analogue was associated with improved intestinal barrier function, it failed to delay the onset of T1D. Once the autoimmune attack is initiated, pathogenic T-cells infiltrate the islets and trigger the death of β-cells. Studies in animal models have revealed that β-cells exhibit a compensatory response in the initial stages of the immune attack, which eventually fails, resulting in β-cell mass deficiency and onset of T1D. Glucagon-like peptide-1 (GLP-1) exerts both proliferative and anti-apoptotic actions on β-cells. I hypothesized that chronic activation of the GLP-1 receptor (GLP-1R) would delay or prevent the loss of functional β-cell mass in the NOD mouse. I have shown that chronic administration of the GLP-1R agonist exendin-4 significantly delayed the onset of diabetes and enhanced β-cell mass. Furthermore, GLP-1R activation was associated with a reduction of islet-infiltrating immune cells, as well as changes in lymphocyte subpopulations. Consequently, I addressed whether the GLP-1R has a role in the immune system of NOD and C57Bl/6 mice. GLP-1R mRNA transcripts were detectable in several immune subpopulations, and GLP-1R activation was associated with cAMP production in primary splenocytes and thymocytes. Furthermore I demonstrated that GLP-1R signaling controls proliferation of thymocytes and lymphocytes, and is required for maintaining peripheral regulatory T-cells. In summary, these studies establish that while GLP-2R activation is not sufficient to modify disease onset in a murine model of T1D, GLP-1R activation reduces the extent of diabetes development by exerting actions on β-cells and the immune system.

La symbiose Methylobacterium nodulans / Crotalaria podocarpa est une symbiose originale. En effet, la méthylotrophie, propriété remarquable de la bactérie, s'exprime à l'apex du nodule et modifie localement le métabolisme : une dégradation apicale marquée des tissus est observée suite à une digestion des parois végétales, libérant du méthanol directement utilisable par la bactérie. Grâce à ce métabolisme, le bactéroïde -de taille et de forme inhabituellement grandes- fournirait l'énergie nécessaire à l'activité de la nitrogénase, et permettrait à la plante d'accumuler des réserves carbonées sous forme d'amyloplastes dans les cellules infectées. Cette propriété méthylotrophique bactérienne apporte également à la plante-hôte un gain de biomasse (>40 % par rapport aux mutants non méthylotrophes). En revanche, à l'échelle de l'espèce, la crotalaire n'est pas avantagée, en termes de fixation d'azote, à s'associer avec M. nodulans ou avec Bradyrhizobium sp., autre genre bactérien décrit en symbiose avec ces plantes. L'originalité de cette association symbiotique se situe également au niveau du dialogue moléculaire : les gènes nod de M. nodulans sont insensibles aux isoflavones, flavonoïdes inducteurs des Bradyrhizobium, mais sont induits par les flavanones et les flavones. L'analyse phylogénétique des gènes nod révèle que M. nodulans forme une branche particulière avec Methylobacterium sp. 4-46 et Burkholderia tuberum STM678, isolées de nodules de Légumineuses appartenant à la tribu des Crotalariae. Au niveau du signal bactérien, une structure unique de facteur Nod a été caractérisée chez M. nodulans ORS2060T : MnV(C18:1, S). Enfin, si la symbiose fonctionnelle M. nodulans/ Crotalaria a été identifiée seulement chez trois espèces de ce genre, la capacité du partenaire bactérien à former des pseudonodules avec d'autres Crotalaria laisse entrevoir un rôle clé de plusieurs composés pendant le processus d'infection suggérant différents mécanismes moléculaires impliqués dans la spécificité d'hôte.

Les cellules iNKT ont des propriétés régulatrices qui suscitent un intérêt particulier en immunopathologie. Mon travail de thèse a eu pour objectif de mesurer l'impact du défaut des cellules iNKT de la souris NOD dans deux situations auto-immunes : 1) le diabète de type 1, une maladie développée spontanément par la souris NOD dans laquelle nous avons montré que les cellules iNKT, tout en constituant des cibles thérapeutiques sous l'impulsion de leur ligand a-GalCer n'ont pas d'activité protectrice spontanée; 2) l'hépatite induite par la ConA, dont la moindre susceptibilité chez la souris NOD a révélé le caractère dominant du rôle délétère de la production d'IL-4 assurée surtout par les cellules iNKT spléniques et non hépatiques et qui est directement potentialisée par l'IL-12, une cytokine qui exacerbe la maladie. En conclusion, notre travail ouvre une nouvelle voie thérapeutique tout en illustrant le caractère ambivalent « mi ange, mi démon » des cellules iNKT en situation auto-immune.

Bone marrow (BM) mesenchymal stem cells (MSC) support proliferation and differentiation of hematopoietic progenitor cells (HPC) in vitro. Since they represent a rare subset of BM cells, MSC preparations for clinical purposes involves a preparative step of ex vivo multiplication. The aim of our study was to analyze the influence of culture duration on MSC supportive activity. MSC were expanded for up to 10 passages. MSC and CD34+ cells were seeded in cytokinefree co-cultures after which the phenotype, clonogenic capacity and in vivo repopulating activity of harvested hematopoietic cells were assessed. Early passage MSC supported HPC expansion and differentiation toward both B lymphoid and myeloid lineages. Late passage MSC did not support HPC and myeloid cell outgrowth but maintained B cell supportive ability. In vitro maintenance of NOD/SCID mouse repopulating cells cultured for one week in contact with MSC was effective until the fourth MSC passage and declined afterwards. CD34+ cells achieved higher levels of engraftment in NOD/SCID mice when co-injected with early passage MSC; however MSC expanded beyond 9 passages were ineffective in promoting CD34+ cell engraftment. Non-contact cultures indicated that MSC supportive activity involved diffusible factors. Among these, interleukin (IL)-6 and IL-8 contributed to the supportive activity of early passage MSC but not of late passage MSC. MSC phenotype as well as fat, bone and cartilage differentiation capacity did not change during MSC culture. Extended MSC culture alters their supportive ability toward HPC without concomitant changes in phenotype and differentiation capacity.

Type 1 diabetes (T1D) is a chronic autoimmune disease in which the insulin producing β-cells in the pancreatic islets of Langerhans are selectively attacked by the immune system. The β-cells are destroyed resulting in a reduced or eliminated insulin production, which in turn lead to a high blood glucose level. The non-obese diabetic (NOD) mouse is the most commonly used animal model for human T1D. NOD mice develop diabetes spontaneously through a process that closely resembles the human pathogenesis. In both humans and the NOD mouse, disease is caused by a combination of genetic and environmental factors. In the NOD mouse, more than 30 insulin-dependent diabetes (Idd) loci on 15 chromosomes have been linked to disease susceptibility, however, most of the Idd-regions lack identification of a disease associated gene. B cells are required for T1D development, although the underlying mechanisms are not fully revealed. The aim of this thesis was to dissect B cell-related immune deviations in the NOD mouse, including the underlying genetics of these traits. The TACI receptor binds two ligands, i.e. the cytokines BAFF and APRIL.TACI ligation by APRIL mediates class switch, drives plasma cell differentiation and increases immunoglobulin production. In Paper I, a novel NOD-specific B cell-related trait was identified, i.e. the increased percentage of TACIhigh-expressing splenic B cells, by comparing NOD mice with non-autoimmune disease prone C57BL/6 mice. To investigate if the described TACI trait was controlled by genes linked to any Idd-region, an Idd-focused linkage analysis was performed. The TACI-trait mapped to regions on chromosome 1 and 8, more specifically to the vicinity of the Idd5.4 and Idd22. Interestingly, the linkage to Idd22 was explained by mice ≥61 days of age, suggesting a temporal genetic regulation of TACI expression possibly influenced by the ongoing autoimmune process. In Paper II, the linkage of the TACI trait to chromosome 1 and 8 was confirmed by analyzing the percentage of TACIhigh-expressing B cells in congenic NOD.C1/Idd22 mice. Moreover, the functional consequence of TACI upregulation was investigated, with the focus on plasma cell development and immunoglobulin production. NOD splenic B cells stimulated with APRIL displayed increased numbers of plasma cells and produced higher amounts of IgG and IgA compared to B cells from C57BL/6 mice. Thus, the TACI upregulation on NOD B cells possibly contribute to a B cell compartment which is more disposed to plasma cell differentiation and isotype switch. NOD mice display enhanced and prolonged immune response towards several antigens, including non-self immunoglobulins. In Paper III, the genetic factor(s) controlling the altered immune response against a BALB/c derived monoclonal antibody were dissected. Significant linkage to the Idd1/Idd24, Idd12, and Idd18.1 regions as well as to a proximal region on chromosome 2 (33.5 Mb) was detected. The linkage to Idd1/24 was verified by analyzing a set of H2-congenic NOD and C57BL/6 mice, and the linked region was narrowed down to ~8 Mb. Candidate gene analysis revealed a significant difference in the transcription of the H2-O/DO molecule. This suggests that multiple mechanisms contribute to the loss of immune response control, including an altered MHC class II peptide loading on NOD B cells. In Paper IV, a novel B cell intrinsic receptor for IgM and IgG was revealed. The receptor appeared to be more abundant in NOD mice compared to C57BL/6 mice, as the level of extramembranous IgG monomers and IgM pentamers on peripheral blood B cells from NOD mice was significantly higher compared to C57BL/6 mice. In addition, analysis of immune complex binding using IgG- or IgM-opsonized bacterial particles revealed a higher degree of binding in NOD mice compared with C57BL/6 mice. The enhanced capture of immunoglobulins and immune complexes could thus contribute to the development of T1D by altering normal B cell functions such as activation and immune complex transportation.

Type 1 Diabetes (T1D) is an autoimmune disorder caused by both genetic and environmental factors. The non-obese diabetic (NOD) mouse is one of the best and most commonly studied animal models for T1D. This mouse strain spontaneously develops diabetes through a process that closely resembles the human pathogenesis. More than 20 insulin dependent susceptibility (Idd) loci have been identified in the NOD mouse, contributing to disease susceptibility; however, the contribution of each of the various factors to disease pathogenesis is largely unknown. The aim of this thesis was to identify and functionally characterize candidate genes mediating susceptibility to murine T1D. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a negative regulator of T-cell activation and has been shown to be associated with autoimmune diseases. Genetic analyses of the NOD mouse have identified the Ctla-4 gene as a major candidate for the Idd5.1 diabetes susceptibility locus and NOD mice have been found to display an impaired expression of CTLA-4 upon anti-CD3 stimulation in vitro. In Paper I, we showed that a novel locus (Ctex) in the distal part of the chromosome 1 together with the Idd3 (Il-2) locus on chromosome 3, constitute the major factors conferring the observed difference in CTLA-4 expression levels. Moreover, we also demonstrated that the defective expression of CTLA-4 in NOD T-cells can in part be overcome by the addition of exogenous interleukin-2 (IL-2). In Paper II, using congenic mice, we confirmed that the Ctex locus contributes to decreased expression of CTLA-4 observed in NOD mice and restricted the region of interest to a 28.8 Mb region containing the Cd3ζ gene. We also demonstrated a phenotypic correlation between strains carrying the NOD versus C57BL/6 alleles of Cd3ζ, respectively and showed that expression of CD3ζ is impaired in activated NOD CD4+ T cells. The NOD allele of the Cd3ζ region was found to confer impaired T cell activation and the defective CD3 signalling could be surpassed by PMA plus ionomycin stimulation supporting the notion of CD3ζ as a prime candidate gene for Ctex. NOD lymphocytes display relative resistance to various apoptosis-inducing signals, which have been proposed to contribute to the pathogenesis of diabetes. Resistance to dexamethasone-induced apoptosis in NOD immature thymocytes has been mapped to the Idd6 locus. In Paper III we restricted the Idd6 locus to an 8 cM region on the telomeric end of chromosome 6 using a set of congenic mice. In addition, we could confirm that the Idd6 region controls apoptosis resistance in immature thymocytes and restricted the control of apoptosis resistance to a 3 cM region within the Idd6 locus. In Paper IV, we further restricted the Idd6 locus to a 3 Mb region and excluded the region controlling the resistance to apoptosis as directly mediating susceptibility to diabetes. We also showed that defective expression of the Lrmp/Jaw1 gene, encoding an endoplasmatic reticulum resident protein, is controlled by the Idd6 locus making it the prime candidate for Idd6.  Together, these results contribute to the identification and functional characterization of candidate genes that may confer susceptibility to T1D in the NOD mouse. These results offer important insights into the pathophysiological processes underlying this disease.

Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / "December 2003." Typescript. Vita. Includes bibliographical references (leaves 146-172). Also issued on the Internet.