multiple sclerosis and IDO

Tryptophan oxidation in biology has been recently implicated in a vast array of paramount pathogenic conditions in humans, including multiple sclerosis, rheumatoid arthritis, type-I diabetes, and cancer. This 2,3-dioxygenative cleavage of the indole ring of tryptophan with dioxygen is mediated by two heme enzymes, tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO), during its conversion to N-formylkynurenine in the first and rate-limiting step of kynurenine pathway. Despite the pivotal significance of this enzymatic transformation, a vivid viewpoint of the precise mechanistic events is far from complete...

Multiple sclerosis (MS), one of the autoimmune and inflammatory diseases, is a major cause of neurological disability worldwide. The existing clinical treatments are not curable, and better treatments are urgently needed. Mesenchymal stromal cells (MSCs) have shown promise for treating MS, but the favorable effects and mechanism of MSC therapy on MS are still not fully understood. In this study, we analyzed the phenotypic feature of peripheral blood mononuclear cells (PBMCs) in MS patients and found that the patients exhibited an increase in the frequency of B cells, but a markedly decrease in frequency of CD5+ and IL-10+ B cells compared to healthy controls...

Reagents that activate the signaling adaptor stimulator of interferon genes (STING) suppress experimentally induced autoimmunity in murine models of multiple sclerosis and arthritis. In this study, we evaluated STING agonists as potential reagents to inhibit spontaneous autoimmune type I diabetes (T1D) onset in non-obese diabetic (NOD) female mice. Treatments with DNA nanoparticles (DNPs), which activate STING when cargo DNA is sensed, delayed T1D onset and reduced T1D incidence when administered before T1D onset...

Multiple sclerosis (MS) is a chronic autoimmune disease with no curative treatment. The immune regulatory properties of type I IFNs have led to the approval of IFN-β for the treatment of relapsing-remitting MS. However, there is still an unmet need to improve the tolerability and efficacy of this therapy. In this work, we evaluated the sustained delivery of IFN-α1, either alone or fused to apolipoprotein A-1 by means of an adeno-associated viral (AAV) system in the mouse model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis...

To dissect therapeutic mechanisms of transplanted stem cells and develop exosome-based nanotherapeutics in treating autoimmune and neurodegenerative diseases, we assessed the effect of exosomes secreted from human mesenchymal stem cells (MSCs) in treating multiple sclerosis using an experimental autoimmune encephalomyelitis (EAE) mouse model. We found that intravenous administration of exosomes produced by MSCs stimulated by IFNγ (IFNγ-Exo) (i) reduced the mean clinical score of EAE mice compared to PBS control, (ii) reduced demyelination, (iii) decreased neuroinflammation, and (iv) upregulated the number of CD4+CD25+FOXP3+ regulatory T cells (Tregs) within the spinal cords of EAE mice...

Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder which most commonly manifests as pulmonary emphysema. Accordingly, alpha-1 antitrypsin (AAT) augmentation therapy aims to reduce the progression of emphysema, as achieved by life-long weekly slow-drip infusions of plasma-derived affinity-purified human AAT. However, not all AATD patients will receive this therapy, due to either lack of medical coverage or low patient compliance. To circumvent these limitations, attempts are being made to develop lung-directed therapies, including inhaled AAT and locally-delivered AAT gene therapy...

Multiple sclerosis (MS) is a progressive neurodegenerative disease, characterized by autoimmune central nervous system (CNS) demyelination attributable to a disturbed balance between encephalitic T helper 1 (Th1) and T helper 17 (Th17) and immunomodulatory regulatory T cell (Treg) and T helper 2 (Th2) cells, and an alternatively activated macrophage (M2) excess. Endogenous molecular systems regulating these inflammatory processes have recently been investigated to identify molecules that can potentially influence the course of the disease...

Type I Interferon (IFN) is widely used for multiple sclerosis (MS) treatment, but its side effects are limiting and its mechanism of action still unknown. Furthermore, 30-50% of MS patients are unresponsive, and IFN can even induce relapses. Fundamental understanding of the cellular target(s) of IFN will help to optimize treatments by reducing side effects and separating beneficial from detrimental effects. To improve clinical systemic IFN usage, we are developing AcTaferons (Activity-on-Target IFNs = AFNs), optimized IFN-based immunocytokines that allow cell-specific targeting...

Objectives: Clinically isolated syndrome (CIS) is the earliest clinical episode in multiple sclerosis (MS). A study of circulating cells from patients with CIS may help us understand the transition to, and processes associated with, the development of MS. Methods: As immune cell activity can be determined by flux through metabolic pathways, the mRNA expression of l-tryptophan- and l-arginine-catabolising enzymes, indoleamine 2,3-dioxygenase (IDO) 1 and IDO2 and arginase (ARG) 1 and ARG2, respectively, was compared between peripheral blood mononuclear cells (PBMCs) from healthy controls, and patients with CIS and definite MS...

Th-17 type immune response that occurs in multiple sclerosis (MS) is linked to CCR6-CCL20 interaction. We confirmed the dependency on CCR6 in EAE development. Vaccination of mice with hCCL20, but not mCCL20, produced anti-murine CCL20 and ameliorated EAE. The EAE clinical score negatively correlated with anti CCL20 levels. A beneficial effect was transferred by sera from hCCL20-immunized mice. Immunized mice with cyclic peptide that include a bacterial outer membrane protein A (ompA), that share homology sequence with hCCL20 produced anti CCL20, anti ompA and anti-cyclic peptide...

Multiple sclerosis (MS) is a chronic debilitating disease of the central nervous system primarily mediated by T lymphocytes with specificity to neuronal antigens in genetically susceptible individuals. On the other hand, myasthenia gravis (MG) primarily involves destruction of the neuromuscular junction by antibodies specific to the acetylcholine receptor. Both autoimmune diseases are thought to result from loss of self-tolerance, which allows for the development and function of autoreactive lymphocytes. Although the mechanisms underlying compromised self-tolerance in these and other autoimmune diseases have not been fully elucidated, one possibility is numerical, functional, and/or migratory deficits in T regulatory cells (Tregs)...

The catabolism of tryptophan to immunosuppressive and neuroactive kynurenines is a key metabolic pathway regulating immune responses and neurotoxicity. The rate-limiting step is controlled by indoleamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO). IDO is expressed in antigen presenting cells during immune reactions, hepatic TDO regulates blood homeostasis of tryptophan and neuronal TDO influences neurogenesis. While the role of IDO has been described in multiple immunological settings, little is known about TDO's effects on the immune system...

The kynurenine pathway (KP) is the major metabolic pathway of the essential amino acid tryptophan (TRP). Stimulation by inflammatory molecules, such as interferon-γ (IFN-γ), is the trigger for induction of the KP, driving a complex cascade of production of both neuroprotective and neurotoxic metabolites, and in turn, regulation of the immune response and responses of brain cells to the KP metabolites. Consequently, substantial evidence has accumulated over the past couple of decades that dysregulation of the KP and the production of neurotoxic metabolites are associated with many neuroinflammatory and neurodegenerative diseases, including Parkinson's disease, AIDS-related dementia, motor neurone disease, schizophrenia, Huntington's disease, and brain cancers...

The kynurenine pathway (KP) of tryptophan metabolism has emerged in recent years as a key regulator of the production of both neuroprotective (e.g. kynurenic and picolinic acid, and the essential cofactor NAD+) and neurotoxic metabolites (e.g. quinolinic acid, 3-hydroxykynurenine). The balance between the production of the two types of metabolites is controlled by key rate-limiting enzymes such as indoleamine-2,3-dioxygenase (IDO-1), and in turn, molecular signals such as interferon-γ (IFN-γ), which activate the KP metabolism of tryptophan by this enzyme, as opposed to alternative pathways for serotonin and melatonin production...

Multiple sclerosis, a debilitating autoimmune and inflammatory disease of the central nervous system, is associated with both infectious and non-infectious factors. We investigated the role of EBV infection, vitamin D level, and cytokine signature in MS patients. Molecular and serological assays were used to investigate immune biomarkers, vitamin D level, and EBV status in 83 patients with relapsing-remitting multiple sclerosis and 62 healthy controls. In total, 98.8 % of MS patients showed a history of EBV exposure compared to 88...

BACKGROUND: Interferon gamma (IFN-γ) production induces the transcription of indoleamine 2,3 dioxygenase (IDO) resulting in the reduction of T-cell activation and proliferation through the depletion of tryptophan and the elicitation of Treg lymphocytes. IDO was shown to be involved in the pathogenesis of autoimmune diseases; we investigated whether changes in IDO gene expression and activity could be indicative of onset of relapse in multiple sclerosis (MS) patients. METHODS: IDO and interferon-γ (IFN-γ) gene expression, serum IDO activity (Kynurenine/Tryptophan ratio) and serum neopterin concentration--a protein released by macrophages upon IFN-γ stimulation--were measured in 51 individuals: 36 relapsing remitting (RR)-MS patients (21 in acute phase--AMS, 15 in stable phase--SMS) and 15 healthy controls (HC)...

Experimental autoimmune encephalomyelitis (EAE) has been widely employed as a model to study multiple sclerosis (MS) and indeed has allowed some important advances in our comprehension of MS pathogenesis. Several pieces of evidence suggest that infiltrating Th1 and Th17 lymphocytes are important players leading to CNS demyelination and lesion during the peak of murine EAE. Subsequently, effector T cell responses rapidly decline and the recovery phase of the disease strongly correlates with the expression of anti-inflammatory cytokines and the enrichment of Foxp3+ regulatory T (Treg) cells within the target organ...

Local catabolism of tryptophan (Trp) by indoleamine 2,3-dioxygenase (IDO) is considered an important mechanism of regulating T cell immunity. N-(3,4-dimethoxycinnamonyl) anthranilic acid (3,4-DAA) is an active synthetic anthranilic acid derivative which was proved to be effective to treat type1helper T lymphocyte (Th1) mediated autoimmune diseases such as multiple sclerosis. In this report, we investigated the effects of 3,4-DAA on the acute graft versus host disease (aGVHD) following allogeneic bone marrow transplantation (allo-BMT) and its potential mechanism of action...

The exact mechanism of glatiramer acetate (GA, Copaxone®), an FDA-approved immunomodulatory therapy for multiple sclerosis (MS), remains unclear after decades of research. Previously, we have shown that GA therapy of MS induces CD8(+) T cell responses that can potentially suppress pathogenic CD4(+) T cell responses. Using a murine model of MS, experimental autoimmune encephalomyelitis (EAE), we now demonstrate that CD8(+) T cells are necessary in mediating the therapeutic effects of GA. Further, adoptive transfer of GA-induced CD8(+) T cells resulted in amelioration of EAE, establishing a role as a viable immunotherapy in demyelinating disease...

BACKGROUND: A growing body of evidence supports the hypothesis that vitamin D is an important environmental factor in the etiology of T-cell-mediated autoimmune diseases such as multiple sclerosis (MS). AIM: The purpose of this study was exploring the mechanisms underlying the beneficial effect of vitamin D3 in encephalomyelitis (EAE). METHODS: We treated monophasic experimental autoimmune EAE, induced in Lewis rat, with vitamin D3 and adoptively transfer tolerogenic bone marrow-derived DCs generated in the presence of vitamin D3...