Abstract : Multiple Sclerosis (MS) is an organ-specific autoimmune disease characterized by the presence of demyelinating plaques throughout the central nervous system (CNS) as a result of an abnormal inflammatory response. During MS, activated microglia can play the role of antigen presenting cells and can, therefore, skew T cell responses towards a pro-inflammatory phenotype. Once activated, microglia upregulate the expression of pro-inflammatory molecules. In addition to microglial responses during MS, astrocytes are also implicated in the development of MS lesions. Upon injury and nearby neuronal death, astrocytes undergo astrogliosis. To date, several molecular pathways were identified as targets for therapeutic interventions for MS such as NF-kB & Nlrs. Nlrs are regulatory proteins of the immune system capable of regulating both innate and adaptive responses. Nlrp12 is a pyrin-containing intracellular protein, largely expressed in cells of myeloid origin. Nlrp12 plays an important role in immune inflammatory responses by negatively regulating the NF-κB pathway and modulatory roles, such as dendritic cell migration. The focus of this study was to evaluate the hypothesis where Nlrp12 plays an anti-inflammatory role in Experimental Autoimmune Encephalomyelitis (EAE), a well-characterized mouse model to study MS. Over a course of 9 weeks, Nlrp12 KO mice demonstrated increased severity in disease levels compared to WT mice. In both genotypes, the disease was observed to peak around the 3rd week post immunization A significant increase in Nlrp12 mRNA was observed in diseased WT compared to healthy WT mice. A significant increase in the expression of CCR5, COX-2, and IL-1 β in Nlrp12 KO mice relative to WT mice, was observed. Interestingly, no differences in the percentage of gliosis was seen at 3 weeks post injection in both genotypes, however after 9 weeks of diseases, in Nlrp12 KO mice we observed a significant increase in the percentage of reactive gliosis compared to WT mice. A significant activation of NF-kB-dependent inflammation was seen in primary microglial cell cultures from Nlrp12 KO relative to WT following LPS stimulation. Moreover, supernatants of analysis for the level of nitrates with Griess reagent and with ELISA for TNFα and IL-6, demonstrated an increase in the pro-inflammatory phenotype from microglia from Nlrp12 KO mice compared to WT mice. These results suggest a critical role of Nlrp12 in suppressing inflammation during the development of the disease given that in its absence, we observed an increase in the inflammatory response. / La sclérose en plaques est une maladie auto-immune déclenchée par une réaction inflammatoire anormale et caractérisée par la dégradation de myéline au niveau du système nerveux central. Durant la sclérose en plaques, la microglie promeut l’expression de molécules pro-inflammatoires et joue le rôle de cellules présentatrices d’antigènes pour forcer les cellules T à adopter un phénotype pro-inflammatoire. Outre les réponses associées à la microglie, les astrocytes sont aussi impliqués dans le développement des lésions. Jusqu’à présent, plusieurs voies moléculaires ont été identifiées comme cibles pour des interventions thérapeutiques tel que les voies de NF-kB et Nlrs. Les récepteurs Nlrs sont des protéines régulatrices du système immunitaire inné et adaptatif. Nlrp12 joue un rôle important dans les réponses inflammatoires immunes en régulant négativement la voie NF-kB et la migration de cellules dendritiques. L’objectif de cette étude est d’étudier l’hypothèse dans laquelle Nlrp12 joue un rôle anti-inflammatoire dans l’encéphalopathie expérimentale autoimmune (EAE), un modèle murin de la sclérose en plaques. Durant 9 semaines, des souris n’exprimant pas Nlrp12 ont démontré un état sévère de la maladie comparativement aux souris de type sauvage (WT). Dans les deux types de génotypes, la maladie était observée à son maximum autour de la 3ème semaine après immunisation. Une augmentation significative de l’expression d’ARNm de Nlrp12 était observée dans les souris contrôles malades comparativement aux souris saines. Une augmentation significative de l’expression de Ccr5, COX-2 ainsi qu’IL-1β était détectée dans les souris Nlrp12 KO par rapport aux souris WT. De plus, aucune différence dans le pourcentage de gliose était observée dans les deux génotypes à 3 semaines post-injection. Par contre, le pourcentage de gliose activée augmentait dans les souris Nlrp12 KO après 9 semaines de maladie. Nous avons remarqué une activation prononcée de l’inflammation dépendante de NF-kB dans des cultures cellulaires primaires de microglie provenant de souris Nlrp12 KO soumise à une stimulation au LPS. Finalement, la quantification des niveaux de nitrates et des cytokines TNFα et IL-6 traduisait une signature pro-inflammatoire de la microglie des souris Nlrp12 KO comparativement aux souris WT. Ces résultats suggèrent un rôle antiinflammatoire de Nlrp12 durant le développement de la sclérose en plaques considérant la réponse inflammatoire accrue en absence de Nlrp12.

Recent reviews (Peyser & Poser, 1986; Rao, 1986) suggest that Multiple Sclerosis results in cognitive impairments in the areas of learning and memory, abstract reasoning, information processing efficiency, and, often, visual-spatial ability. Whether this pattern applies to the individual with MS is unclear. Due to the disseminated distribution of MS neuropathology, patients may undergo idiosyncratic cognitive changes dependent upon the site of white matter lesions. The present study explored this question using cluster analysis on the neuropsychological data from a group of mildly disabled MS patients (n = 177) and a well-matched control group (n=89). In a group of MS patients who were identified with unequivocal cognitive impairment, the resultant clusters indicated that MS does not result in a characteristic pattern of impairment. Two clusters were obtained that resembled the pattern described in the literature, while the majority of patients clustered into groups with specific deficits in one or two areas, with normal performance in others. In order to identify associations between cluster groups and lesion sites, frequency tables were constructed for the presence of a lesion on Magnetic Resonance Imaging in 24 brain sites. An association was obtained between two lesion sites and two cognitive tests. Visual-spatial impairment, as assessed by the Benton Visual Retention test, was associated with lesions in the genu of the corpus callosum and with more lesions throughout the corpus callosum. Impaired performance on Paired Associates, a test of learning and memory for novel verbal associations, was associated with a lesion in the deep white matter of the left parietal lobe. The results support the hypothesis that MS results in multiple patterns of cognitive impairment depending on the individual placement of white matter lesions. Identifying and characterizing the heterogeneity of the impairment may greatly increase our understanding of the role of myelin in cognition and the functions of white matter tracts in the brain. / Arts, Faculty of / Psychology, Department of / Graduate

Interleukin (IL) -7 is an essential non-redundant cytokine that influences T-cell differentiation, proliferation, homeostasis and T-cell functions. In T-cells, IL-7 signals are transduced via IL-7's heterodimeric receptor composed of a common, γ chain (CD132) and an IL-7 specific, α chain (CD127). In light of the many roles that IL-7 plays in T-cell biology, it is no surprise that CD127 expression is tightly regulated in T-cells. In this study, I explore the effects that disease specific mutations in CD127 have on CD127 expression, regulation and signal transduction using an in vitro T-cell model. Here I specifically examined four disease associated mutations of CD127: P132S associated with severe combined immunodeficiency; L242_L243insNPC associated with T-cell acute lymphoblastic leukemia; I356V & T244I associated with autoimmune diseases like multiple sclerosis, rheumatoid arthritis and type 1 diabetes. In developing my model, I decided to use Jurkat cells because they expressed high endogenous surface levels of CD132, low endogenous surface levels of CD127 and endogenous STAT5. Jurkat cells were transduced with lentiviruses that induced expression of either WT or one of the four mutant CD127. I found that transduced Jurkat cells produced the WT and all four mutant CD127 proteins. I also found that wild type CD127, I356V, L242_L243insNPC and T244I mutant CD127 proteins were all expressed at the same level on the cell surface. However, I could not detect P132S mutated CD127 protein in its native state on the surface or intracellularly. I also found no differences between the mutant CD127 and wild type CD127 with regards to the level of soluble CD127 transcripts. I found that cell lines expressing L242_L243insNPC, I356V and T244I mutant CD127 protein, down-regulated surface CD127 at high IL-7 doses (25ng/mL) to the same extent as in the cell line expressing wild type CD127 protein. Interestingly, at the low IL-7 dose (1ng/mL) these mutant CD127 cell lines down-regulated surface CD127 to a lesser degree the wild type CD127 cell line. Further studies are required to elucidate whether P132S mutated CD127 is expressed on the surface and if T224I and I356V mutations in CD127 enhance signaling. By understanding CD127 dysregulation and dysfunction in disease states, we can potentially develop therapeutics that can return the function of CD127 to normalcy.

La sclérose en plaques (SEP) est une maladie chronique, autoimmune, inflammatoire, démyélinisante et dégénérative du système nerveux central (SNC). Le rôle des lymphocytes B (LB) dans la pathogénèse de la SEP reste complexe, décrit parfois comme pathogène, régulateur ou réparateur. Dans un premier temps, notre travail a été réalisé sur un modèle animal de SEP, l’encéphalomyélite auto-immune expérimentale (EAE). Le modèle à rechutes, induit par immunisation active de souris femelles SJL/J (H2s) par le peptide encéphalitogène de la protéine protéolipidique de la myéline (pPLP139-151) a été utilisé. La comparaison avec des souris femelles B10.S, congéniques pour le complexe H2, et décrites comme résistantes car ne développant pas de signes cliniques caractéristiques de l’EAE après immunisation active, nous a permis d’étudier l’implication des sous-populations lymphocytaires B au cours du développement de la pathologie. L’utilisation de ces modèles susceptible/résistant nous a permis de démontrer l’implication de l’homéostasie des sous-populations lymphocytaires B dans la physiopathologie de la réponse auto-immune. Dans un second temps, ces observations ont été confirmées par des études réalisées chez l’Homme, dont la répartition des sous-populations lymphocytaires B circulantes présente un déséquilibre homéostatique lors des premières phases de la maladie. En effet, nous avons observé que les LB transitionnels, aussi connus sous le nom de LB immatures tardifs, présentent des altérations quantitatives (nombre de cellules circulantes) et qualitatives (état d’activation particulier et expression accrue de molécules d’adhésions impliquées dans le processus d’extravasation leucocytaire). Ces caractéristiques, spécifiques des LB transitionnels de patients SEP, ont été associées au recrutement de ces cellules au sein du SNC. Ces résultats originaux mettent en exergue que les LB mémoires et les plasmablastes ne sont pas les seules populations lymphocytaires B impliquées dans de développement de la SEP. / Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system (CNS). The role of B-lymphocytes in MS pathogenesis remains unclear, since they have been described to have pathogenic and regulatory effects, and also to be involved in remyelination process. To better understand the mechanisms underlying MS, we used the well-studied animal model, known as experimental autoimmune encephalomyelitis (EAE) induced by the encephalitogenic peptide 139-151 of the myelin proteolipid (PLP139-151) in females SJL/J mice, which presents at least one relapsing/remitting episode. Unlike SJL/J model, females B10.S (congenic for the H2 complex) do not develop the clinical signs characteristics of the EAE after active immunization. Thus, B10.S mice are considered as resistant to the disease induction. The experimental approach carried out in the susceptible/resistant EAE models highlighted the involvement of the B-cell homeostasis on the physiopathology of the autoimmune responses. These observations were confirmed in patients with MS, which showed altered B-cell subsets balance during the early phases of the disease. In fact, transitional B cells, also known as late-immature B cells, showed quantitative (cell numbers) and qualitative (a particular activation status and an increased expression of several adhesion molecules involved in the leukocyte extravasation) modifications. These characteristics, exclusively found in transitional B cells from patients with MS, were associated to their ability to home the central nervous system. Altogether these findings highlighted that B-cell involvement in MS pathogenesis may not be exclusively restricted to memory B cells.

Multiple sclerosis (MS) is a debilitating disease in which demyelinated lesions form in the central nervous system (CNS). A specific microRNA, miR-145-5p, is dysregulated both in blood samples from RRMS patients and in chronic lesions from progressive MS patients. In the context of remyelination, miR-145-5p regulation may be important as it exhibits strong differential regulation in oligodendrocytes (OLs), the myelinating cells of the CNS, and is also expressed in other CNS glial cell types. Dysregulation of miR-145-5p may therefore play into pathologies observed in both relapsing-remitting (RRMS) and progressive MS. Using pre-clinical rodent models, we aimed to determine how altering normal expression of miR-145-5p specifically affects OL maturation, and how the dysregulation observed in MS may affect various aspects of disease. First using a miR-145 knockdown model in primary rat OLs, we found in vitro that miR-145-5p plays a role both in maintaining oligodendrocyte progenitor cells (OPCs) in their proliferative state and preventing premature differentiation to OLs and that knockdown of miR-145 in OLs enhanced their differentiation. These effects were due at least in part to miR-145-5p regulation of a critical myelin gene transcription factor. The effects of miR-145-5p were further assessed in a miR-145 knockout mouse model in vivo. Contrary to in vitro assays, enhanced myelination was not detectable during development in these animals, nor when remyelination was assessed using the cuprizone toxic model of acute demyelination. However, chronic cuprizone exposure resulted in striking remyelination and functional recovery in miR-145 deficient animals. Sparse remyelination in wild-type animals with chronic cuprizone exposure was concomitant with upregulation of miR-145-5p, which was not the case with acute exposure, identifying miR-145-5p dysregulation as a unique feature of chronic demyelination. Specific assessment of miR-145-5p overexpression in OLs in vitro resulted in severe differentiation deficits and eventual apoptosis, driven molecularly by altered expression of multiple pathways critical to successful OL differentiation and subsequent myelination. Finally, we induced an inflammatory model of demyelination, experimental autoimmune encephalomyelitis (EAE), in our miR-145 knockout mouse to assess the role of miR-145-5p in autoimmune-mediated myelin damage. The clinical severity of EAE in miR-145 deficient animals was reduced, and this was accompanied by reduced loss of myelin and lessened immune cell infiltration in miR-145 knockout spinal cords. Alterations in both astrocytic and microglial activation were detected with loss of miR-145, suggesting that improved clinical outcomes in this model may be underpinned by changes in EAE-mediated neuroinflammation. Collectively, these data suggest that miR-145-5p plays differing roles in both progressive and inflammatory MS, affecting multiple glial cell types in the CNS. Excitingly, loss of miR-145 expression in our mouse model of chronic demyelination allowed extensive remyelination and functional recovery following chronic demyelination, and in EAE improved clinical outcomes driven by underlying improvements in myelin retention and altered neuroinflammatory reactions. Thus, miR-145-5p merits further investigation as a potential therapeutic target to help overcome both remyelination failure in all forms of progressive MS and inflammation-driven demyelination in RRMS and early secondary progressive MS (SPMS).

No description available.

Although recent literature suggests that fatigue influences the communication of people with multiple sclerosis (MS), its relationship to acoustic measures of speech, specifically formant transitions during diphthongs, has not been explored. In the present study, 11 participants diagnosed with MS, two of whom were perceptually dysarthric, and 12 control subjects were recorded as they performed selected speech tasks in both the morning and the afternoon. Before each recording session, participants rated their fatigue level. The participants with MS gave significantly higher ratings of fatigue than the control group. The speakers with MS had longer diphthong durations in a non-fatigued state, but not in a fatigued state, which was indicative of the variability in this group of speakers. Fatigue was not shown to affect any other acoustic variables. This finding may be attributable to the mildness of the speech impairment of this sample of speakers with MS.

Matrix Metalloproteinase-28 (MMP-28) is the newest and least characterized member of MMP family. To date several potential substrate candidates for MMP-28 have been proposed but no in vivo substrates for this enzyme were confirmed. In the central nervous system (CNS) MMP-28 is believed to be important factor during myelination of the developing nervous system as well as during remyelination that follows neuronal injury. On the other hand, MMP-28 has been found in actively demyelinating lesions in both experimental autoimmune encephalopathy (EAE) and multiple sclerosis patients suggesting its possible role in pathological events associated with autoimmune neurodegenerative processes. In addition, MMP-28 has been linked to modulation of immune response and activation of macrophages which presents another role of this enzyme in autoimmune pathologies. In the study described herein, MMP-28 has been shown to affect myelin composition and appearance, mitochondrial protein content, and vesicular transport proteins. Moreover, the decrease in myelin basic protein quantity observed in healthy MMP-28KO animals affected the myelin staining intensity in various brain regions including corpus callous. Cellular energetic studies did not reveal differences in mitochondrial function in MMP-28KO animals and no difference in reactive oxygen species was observed. In the EAE model, MMP-28 deletion increased the occurrence of atypical form of EAE characterized by increased inflammation of arbor vitae of the brain. In addition, MMP-28 deletion decreased the inflammatory infiltrates present in brains obtained from EAE animals. Lastly, MMP-28 has been shown to affect cellular energetics and activation of bone marrow derived macrophages during the initial stages and after 24 h activation. In addition, MMP-28 deletion increased proinflammatory cytokines and receptors CD86 and iNOS found in M1 polarized macrophages. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Multiple sclerosis is a demyelinating disease affecting the central nervous system. It is the most prevalent disabling neurological condition among young adults, with onset typically between 20 and 40 years of age. Infiltrating immune cells and microglia activations are associated with inflammatory and neurodegenerative mechanisms. Current available disease modifying therapies suppress or modulate the immune system. These pharmaceuticals differ with respect to administration route and frequency, adverse effects, and efficacy. This paper provides a thorough manuscript illustrating the major prescribing factors, efficacy profiles, adverse events, and contraindications that patients and clinicians should consider while choosing a treatment. Despite the advancements made over the past 20 years, patients with progressive multiple sclerosis have few therapeutic options. Additionally, this paper assesses emerging therapies and disease targets on the pharmaceutical horizon, which have shown promise for all disease phenotypes.

MS is an autoimmune neurodegenerative disease that attacks myelin, a protective sheath that covers neurons within our bodies, which may lead to numbness, tremors, issues with vision, dizziness and more. When researching the efficacy of a therapeutic in neurodegenerative diseases such as multiple sclerosis, it is crucial that the in-vivo model selected for testing allows complete and accurate data collection. Several models attempt to replicate conditions of disease, in which myelin levels have been deliberately reduced in order to study its regrowth. These models (Cuprizone and LPC injection) can be further optimized by validating a new strain of mouse, NG2-creER / Rosa-Optopatch, which will essentially express GFP+ myelin. To validate this mouse line, the following goals were pursued: Confirm NG2+ pre-OLs express GFP in the spinal cord tissue and corpus callosum in our NG2-creER mouse, confirm that myelin formed from NG2+ pre-OLs that have matured into OLs also express GFP and characterize the GFP staining pattern along with other known myelin stains (MBP, Fluoromyelin Red), and in the long run, use the NG2-creER model in MS-related targets for drug candidates as a more efficient option than traditional methods such as electron microscopy (EM). Results show that the NG2-creER mouse was successful (in both CPZ and LPC models) in showing NG2+/GFP+ cells and that these GFP+ pre-OLs matured to form GFP+ myelin, as well as showing the capability of staining myelin at a younger age than other myelin stains. / 2022-06-17T00:00:00Z