ABSTRACT
Disease-associated astrocyte subsets contribute to the pathology of neurologic diseases, including multiple sclerosis and experimental autoimmune encephalomyelitis1-8 (EAE), an experimental model for multiple sclerosis. However, little is known about the stability of these astrocyte subsets and their ability to integrate past stimulation events. Here we report the identification of an epigenetically controlled memory astrocyte subset that exhibits exacerbated pro-inflammatory responses upon rechallenge. Specifically, using a combination of single-cell RNA sequencing, assay for transposase-accessible chromatin with sequencing, chromatin immunoprecipitation with sequencing, focused interrogation of cells by nucleic acid detection and sequencing, and cell-specific in vivo CRISPR-Cas9-based genetic perturbation studies we established that astrocyte memory is controlled by the metabolic enzyme ATP-citrate lyase (ACLY), which produces acetyl coenzyme A (acetyl-CoA) that is used by histone acetyltransferase p300 to control chromatin accessibility. The number of ACLY+p300+ memory astrocytes is increased in acute and chronic EAE models, and their genetic inactivation ameliorated EAE. We also detected the pro-inflammatory memory phenotype in human astrocytes in vitro; single-cell RNA sequencing and immunohistochemistry studies detected increased numbers of ACLY+p300+ astrocytes in chronic multiple sclerosis lesions. In summary, these studies define an epigenetically controlled memory astrocyte subset that promotes CNS pathology in EAE and, potentially, multiple sclerosis. These findings may guide novel therapeutic approaches for multiple sclerosis and other neurologic diseases.
Subject(s)
Astrocytes , Encephalomyelitis, Autoimmune, Experimental , Epigenetic Memory , Multiple Sclerosis , Animals , Female , Humans , Male , Mice , Acetyl Coenzyme A/metabolism , Astrocytes/enzymology , Astrocytes/metabolism , Astrocytes/pathology , ATP Citrate (pro-S)-Lyase/metabolism , Chromatin/genetics , Chromatin/metabolism , Chromatin Assembly and Disassembly , Chromatin Immunoprecipitation Sequencing , CRISPR-Cas Systems , Encephalomyelitis, Autoimmune, Experimental/enzymology , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/metabolism , Encephalomyelitis, Autoimmune, Experimental/pathology , Inflammation/enzymology , Inflammation/genetics , Inflammation/metabolism , Inflammation/pathology , Multiple Sclerosis/enzymology , Multiple Sclerosis/genetics , Multiple Sclerosis/metabolism , Multiple Sclerosis/pathology , Single-Cell Gene Expression Analysis , Transposases/metabolismABSTRACT
Multiple sclerosis (MS) is a chronic central nervous system (CNS) disorder characterized by demyelination, neuronal damage, and oligodendrocyte depletion. Reliable biomarkers are essential for early diagnosis and disease management. Emerging research highlights the role of mitochondrial dysfunction and oxidative stress in CNS disorders, including MS, in which mitochondria are central to the degenerative process. Adenosine monophosphate-activated protein kinase (AMPK) regulates the mitochondrial energy balance and initiates responses in neurodegenerative conditions. This systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, aimed to comprehensively assess the literature on AMPK pathways, mitochondrial dysfunction, and in vivo studies using MS animal models. The search strategy involved the use of AMPK syntaxes, MS syntaxes, and animal model syntaxes. The PubMed, Scopus, Web of Science, and Google Scholar databases were systematically searched on August 26, 2023 without publication year restrictions. The review identified and analyzed relevant papers to provide a comprehensive overview of the current state of related research. Eight studies utilizing various interventions and methodological approaches were included. Risk of bias assessment revealed some areas of low risk but lacked explicit reporting in others. These studies collectively revealed a complex relationship between AMPK, mitochondrial dysfunction, and MS pathogenesis, with both cuprizone and experimental autoimmune encephalomyelitis models demonstrating associations between AMPK and mitochondrial disorders, including oxidative stress and impaired expression of mitochondrial genes. These studies illuminate the multifaceted role of AMPK in MS animal models, involving energy metabolism, inflammatory processes, oxidative stress, and gene regulation leading to mitochondrial dysfunction. However, unanswered questions about its mechanisms and clinical applications underscore the need for further research to fully harness its potential in addressing MS-related mitochondrial dysfunction.
Subject(s)
AMP-Activated Protein Kinases , Encephalomyelitis, Autoimmune, Experimental , Mitochondria , Multiple Sclerosis , Animals , Humans , AMP-Activated Protein Kinases/metabolism , AMP-Activated Protein Kinases/genetics , Encephalomyelitis, Autoimmune, Experimental/enzymology , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/pathology , Mitochondria/pathology , Mitochondria/genetics , Mitochondria/metabolism , Multiple Sclerosis/genetics , Multiple Sclerosis/pathology , Multiple Sclerosis/enzymology , Oxidative StressABSTRACT
Multiple sclerosis (MS) is a chronic, immune-mediated, neurodegenerative condition that results in progressive accumulation of disability over the course of the disease. MS presents heterogeneously, and, as the disease progresses, patients develop a range of physical and neurologic problems that include reduced mobility, cognitive impairment, weakness, fatigue, pain, and defects in speech or vision. Economically, MS is costly, including both direct costs stemming from clinical care and medications and the indirect costs of productivity losses. These costs pose a substantial burden to patients, families, caregivers, employers, and society. There are 21 approved disease-modifying therapies for MS across several drug classes. The importance of early MS treatment has been confirmed, and progress has been made in the treatment of relapsing-remitting MS, although this progress has not been replicated for progressive presentations of the disease. Ongoing research continues to elucidate the exact mechanisms of disease in MS as well as potential new treatment strategies that may better address current gaps, such as disability progression in secondary progressive MS without activity. One of the novel pathways under investigation is the inhibition of Bruton tyrosine kinase, a cytoplasmic tyrosine kinase, which is expressed in B cells and other potentially targetable hematopoietic lineage cells. This review examines emerging hypotheses that targeting both B cells and myeloid cells within the periphery and central nervous system could yield clinical effects in key areas of MS pathophysiology that are currently unaddressed.
Subject(s)
Agammaglobulinaemia Tyrosine Kinase , Multiple Sclerosis , Humans , Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Agammaglobulinaemia Tyrosine Kinase/metabolism , Multiple Sclerosis/drug therapy , Multiple Sclerosis/enzymology , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Multiple Sclerosis, Relapsing-Remitting/enzymology , Metabolic Networks and Pathways , B-Lymphocytes/drug effects , B-Lymphocytes/enzymology , Myeloid Cells/drug effects , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic useABSTRACT
Caspase-8 functions at the crossroad of programmed cell death and inflammation. Here, using genetic approaches and the experimental autoimmune encephalomyelitis model of inflammatory demyelination, we identified a negative regulatory pathway for caspase-8 in infiltrated macrophages whereby it functions to restrain interleukin (IL)-1ß-driven autoimmune inflammation. Caspase-8 is partially activated in macrophages/microglia in active lesions of multiple sclerosis. Selective ablation of Casp8 in myeloid cells, but not microglia, exacerbated autoimmune demyelination. Heightened IL-1ß production by caspase-8-deficient macrophages underlies exacerbated activation of encephalitogenic T cells and production of GM-CSF and interferon-γ. Mechanistically, IL-1ß overproduction by primed caspase-8-deficient macrophages was mediated by RIPK1/RIPK3 through the engagement of NLRP3 inflammasome and was independent of cell death. When instructed by autoreactive CD4 T cells in the presence of antigen, caspase-8-deficient macrophages, but not their wild-type counterparts, released significant amount of IL-1ß that in turn acted through IL-1R to amplify T cell activation. Moreover, the worsened experimental autoimmune encephalomyelitis progression in myeloid Casp8 mutant mice was completely reversed when Ripk3 was simultaneously deleted. Together, these data reveal a functional link between T cell-driven autoimmunity and inflammatory IL-1ß that is negatively regulated by caspase-8, and suggest that dysregulation of the pathway may contribute to inflammatory autoimmune diseases, such as multiple sclerosis.
Subject(s)
Caspase 8 , Encephalomyelitis, Autoimmune, Experimental , Multiple Sclerosis , Receptor-Interacting Protein Serine-Threonine Kinases , Animals , CD4-Positive T-Lymphocytes/immunology , Caspase 1/metabolism , Caspase 8/genetics , Caspase 8/metabolism , Encephalomyelitis, Autoimmune, Experimental/enzymology , Encephalomyelitis, Autoimmune, Experimental/immunology , Inflammasomes/metabolism , Inflammation/metabolism , Interleukin-1beta/metabolism , Mice , Mice, Inbred C57BL , Multiple Sclerosis/enzymology , Multiple Sclerosis/immunology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Receptor-Interacting Protein Serine-Threonine Kinases/genetics , Receptor-Interacting Protein Serine-Threonine Kinases/metabolismABSTRACT
Fyn is a non-receptor tyrosine kinase belonging to the Src family of kinases (SFKs) which has been implicated in several integral functions throughout the central nervous system (CNS), including myelination and synaptic transmission. More recently, Fyn dysfunction has been associated with pathological processes observed in neurodegenerative diseases, such as multiple sclerosis (MS), Alzheimer's disease (AD) and Parkinson's disease (PD). Neurodegenerative diseases are amongst the leading cause of death and disability worldwide and, due to the ageing population, prevalence is predicted to rise in the coming years. Symptoms across neurodegenerative diseases are both debilitating and degenerative in nature and, concerningly, there are currently no disease-modifying therapies to prevent their progression. As such, it is important to identify potential new therapeutic targets. This review will outline the role of Fyn in normal/homeostatic processes, as well as degenerative/pathological mechanisms associated with neurodegenerative diseases, such as demyelination, pathological protein aggregation, neuroinflammation and cognitive dysfunction.
Subject(s)
Nerve Tissue Proteins/physiology , Neurodegenerative Diseases/enzymology , Proto-Oncogene Proteins c-fyn/physiology , Alzheimer Disease/drug therapy , Alzheimer Disease/enzymology , Alzheimer Disease/physiopathology , Amyloid beta-Peptides/metabolism , Benzamides/pharmacology , Benzamides/therapeutic use , Central Nervous System/enzymology , Dasatinib/pharmacology , Dasatinib/therapeutic use , Humans , Molecular Targeted Therapy , Multiple Sclerosis/drug therapy , Multiple Sclerosis/enzymology , Myelin Sheath/physiology , Nerve Tissue Proteins/drug effects , Neurodegenerative Diseases/drug therapy , Neurodegenerative Diseases/physiopathology , Oligodendroglia/metabolism , Parkinson Disease/drug therapy , Parkinson Disease/enzymology , Parkinson Disease/physiopathology , Piperidines/pharmacology , Piperidines/therapeutic use , PrPC Proteins/metabolism , Proto-Oncogene Proteins c-fyn/antagonists & inhibitors , Proto-Oncogene Proteins c-fyn/drug effects , Pyridines/pharmacology , Pyridines/therapeutic use , Receptors, N-Methyl-D-Aspartate/metabolism , T-Cell Antigen Receptor Specificity , T-Lymphocyte Subsets/enzymology , T-Lymphocyte Subsets/immunology , Thiazoles/pharmacology , Thiazoles/therapeutic use , tau Proteins/metabolismABSTRACT
In patients with multiple sclerosis (MS) disease, cognitive deficits have been detected because of destruction of hippocampus. Cognitive impairment is one of the common signs in MS. Recent studies showed that metformin (Met) has wide-ranging effects in the treatment of diseases. Here, we have tried to study the preservative effects of Met as adenosine monophosphate-activated protein kinase (AMPK) activator on the hippocampus dentate gyrus (DG) neuronal firing pattern, motor coordination, and learning & memory loss following MS induction. The MS induction was done by local ethidium bromide (EB) injection into the rat hippocampus. Then, rats were treated with Met (200 mg/kg) for two weeks. Spatial memory and learning status were assessed using Morris water maze. A neuronal single-unit recording was measured from hippocampus DG. After decapitation, the bilateral hippocampi separated to measure malondialdehyde (MDA). Treatment with Met ameliorated latency times and path lengths (P < 0.05, P < 0.01, P < 0.001 in 1th, 2th, 3th and 4th days) in the Met + MS group respectively. The percent of total time spent in goal quarter and the average number of spikes/bin were decreased significantly in MS rats compared with the sham group (p < 0.001) but significantly increased in the metformin-treated MS group (Met + MS), (p < 0.01, p < 0.001). Met treatment in rats with MS significantly reduced the concentration of MDA, which is an indicator of lipid peroxidation compared to untreated groups. These observations show that increase of neuronal activity, sensory-motor coordination, and improvement of spatial memory in MS rats treated with Met appears via an increment of AMPK.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Metformin/therapeutic use , Multiple Sclerosis/drug therapy , Multiple Sclerosis/enzymology , Spatial Learning/drug effects , Spatial Memory/drug effects , Animals , Disease Models, Animal , Drug Evaluation, Preclinical/methods , Enzyme Activation/drug effects , Enzyme Activation/physiology , Hippocampus/drug effects , Hippocampus/enzymology , Male , Metformin/pharmacology , Rats , Rats, Wistar , Spatial Learning/physiology , Spatial Memory/physiology , Treatment OutcomeABSTRACT
The brain 3ß-hydroxysteroid dehydrogenase (3ß-HSD), is the enzyme that catalyzes the biosynthesis of a neuroprotective factor, progesterone. The regulation of 3ß-HSD in response to stress exposure in the cuprizone-induced model of Multiple Sclerosis was investigated and the reaction related to the demyelination extremity. 32 female Wistar rats divided into four groups (i.e., control group (Cont), non-stress cuprizone treated (N-CPZ), physical stress- cuprizone treated (P-CPZ) and emotional stress- cuprizone treated (E-CPZ). A witness foot-shock model used to induce background stress for 5 days. An elevated-plus maze applied to validate the stress induction. Followed by 6 weeks of cuprizone treatment, the Y-maze test performed to confirm brain demyelination. 3ß-HSD gene expression as an indicator of progesterone synthesis examined. At the behavioral level, both stressed groups reflected more impaired spatial memory compared to the N-CPZ group (p < 0.01), with more severe results in the E-CPZ group (p < 0.01). The results of mRNA expression of 3ß-HSD illustrated significant elevation in all cuprizone treated groups (p < 0.001) with a higher up-regulation (p < 0.001) in the E-CPZ group. Background stress -particularly emotional type- exacerbates the demyelination caused by cuprizone treatment. The brain up-regulates the 3ß-HSD gene expression as a protective response relative to the myelin degradation extent.
Subject(s)
3-Hydroxysteroid Dehydrogenases/genetics , Disease Models, Animal , Multiple Sclerosis/enzymology , Psychological Distress , 3-Hydroxysteroid Dehydrogenases/biosynthesis , Animals , Anxiety/pathology , Anxiety/psychology , Cuprizone , Demyelinating Diseases/pathology , Electroshock , Female , Maze Learning , Multiple Sclerosis/genetics , Multiple Sclerosis/pathology , Neuroprotection , Psychomotor Performance/drug effects , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Rats , Rats, Wistar , Up-RegulationABSTRACT
Haem oxygenase 1 (HO-1), an inducible enzyme responsible for the breakdown of haem, is primarily considered an antioxidant, and has long been overlooked by immunologists. However, research over the past two decades in particular has demonstrated that HO-1 also exhibits numerous anti-inflammatory properties. These emerging immunomodulatory functions have made HO-1 an appealing target for treatment of diseases characterized by high levels of chronic inflammation. In this Review, we present an introduction to HO-1 for immunologists, including an overview of its roles in iron metabolism and antioxidant defence, and the factors which regulate its expression. We discuss the impact of HO-1 induction in specific immune cell populations and provide new insights into the immunomodulation that accompanies haem catabolism, including its relationship to immunometabolism. Furthermore, we highlight the therapeutic potential of HO-1 induction to treat chronic inflammatory and autoimmune diseases, and the issues faced when trying to translate such therapies to the clinic. Finally, we examine a number of alternative, safer strategies that are under investigation to harness the therapeutic potential of HO-1, including the use of phytochemicals, novel HO-1 inducers and carbon monoxide-based therapies.
Subject(s)
Antioxidants/metabolism , Heme Oxygenase-1/metabolism , Inflammation/enzymology , Animals , Anti-Inflammatory Agents/immunology , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Carbon Monoxide/metabolism , Dendritic Cells/immunology , Dendritic Cells/metabolism , Enzyme Induction/drug effects , Gene Expression Regulation, Enzymologic , Heme Oxygenase-1/genetics , Heme Oxygenase-1/immunology , Humans , Inflammation/drug therapy , Inflammation/immunology , Inflammatory Bowel Diseases/drug therapy , Inflammatory Bowel Diseases/enzymology , Inflammatory Bowel Diseases/immunology , Macrophages/immunology , Macrophages/metabolism , Models, Biological , Multiple Sclerosis/drug therapy , Multiple Sclerosis/enzymology , Multiple Sclerosis/immunology , Phytochemicals/therapeutic use , Pneumonia/drug therapy , Pneumonia/enzymology , Pneumonia/immunology , Psoriasis/drug therapy , Psoriasis/enzymology , Psoriasis/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Transplantation ImmunologyABSTRACT
Various neurodegenerative disorders have various molecular origins but some common molecular mechanisms. In the current scenario, there are very few treatment regimens present for advanced neurodegenerative diseases. In this context, there is an urgent need for alternate options in the form of natural compounds with an ameliorating effect on patients. There have been individual scattered experiments trying to identify potential values of various intracellular metabolites. Purines and Pyrimidines, which are vital molecules governing various aspects of cellular biochemical reactions, have been long sought as crucial candidates for the same, but there are still many questions that go unanswered. Some critical functions of these molecules associated with neuromodulation activities have been identified. They are also known to play a role in foetal neurodevelopment, but there is a lacuna in understanding their mechanisms. In this review, we have tried to assemble and identify the importance of purines and pyrimidines, connecting them with the prevalence of neurodegenerative diseases. The leading cause of this class of diseases is protein misfolding and the formation of amyloids. A direct correlation between loss of balance in cellular homeostasis and amyloidosis is yet an unexplored area. This review aims at bringing the current literature available under one umbrella serving as a foundation for further extensive research in this field of drug development in neurodegenerative diseases.
Subject(s)
Gene Expression Regulation/drug effects , Metabolic Networks and Pathways/genetics , Purines/therapeutic use , Pyrimidines/therapeutic use , Alzheimer Disease/drug therapy , Alzheimer Disease/enzymology , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Amyloidosis/drug therapy , Amyloidosis/enzymology , Amyloidosis/genetics , Amyloidosis/pathology , Ataxia Telangiectasia Mutated Proteins/genetics , Ataxia Telangiectasia Mutated Proteins/metabolism , Humans , Huntington Disease/drug therapy , Huntington Disease/enzymology , Huntington Disease/genetics , Huntington Disease/pathology , Hypoxanthine Phosphoribosyltransferase/genetics , Hypoxanthine Phosphoribosyltransferase/metabolism , Multiple Sclerosis/drug therapy , Multiple Sclerosis/enzymology , Multiple Sclerosis/genetics , Multiple Sclerosis/pathology , Neurofibrillary Tangles/drug effects , Neurofibrillary Tangles/enzymology , Neurofibrillary Tangles/genetics , Neurofibrillary Tangles/pathology , Neurons/drug effects , Neurons/enzymology , Neurons/pathology , Parkinson Disease/drug therapy , Parkinson Disease/enzymology , Parkinson Disease/genetics , Parkinson Disease/pathology , Phosphotransferases (Alcohol Group Acceptor)/genetics , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Purines/metabolism , Pyrimidines/metabolism , Synapses/drug effects , Thymidine Phosphorylase/genetics , Thymidine Phosphorylase/metabolismABSTRACT
PURPOSE: Molecular imaging agents targeting butyrylcholinesterase (BChE) have shown promise in other neurodegenerative disorders and may have utility in detecting changes to normal appearing white matter in multiple sclerosis (MS). BChE activity is present in white matter and localizes to activated microglia associated with MS lesions. The purpose of this study was to further characterize changes in the cholinergic system in MS pathology, and to explore the utility of BChE radioligands as potential diagnostic and treatment monitoring agents in MS. PROCEDURE: Cortical and white matter lesions were identified using myelin staining, and lesions were classified based on microglial activation patterns. Adjacent brain sections were used for cholinesterase histochemistry and in vitro autoradiography using phenyl 4-[123I]-iodophenylcarbamate (123I-PIP), a previously described small-molecule cholinesterase-binding radioligand. RESULTS: BChE activity is positively correlated with microglial activation in white matter MS lesions. There is no alteration in cholinesterase activity in cortical MS lesions. 123I-PIP autoradiography revealed uptake of radioactivity in normal white matter, absence of radioactivity within demyelinated MS lesions, and variable uptake of radioactivity in adjacent normal-appearing white matter. CONCLUSIONS: BChE imaging agents have the potential to detect MS lesions and subtle pathology in normal-appearing white matter in postmortem MS brain tissue. The possibility of BChE imaging agents serving to supplement current diagnostic and treatment monitoring strategies should be evaluated.
Subject(s)
Butyrylcholinesterase/metabolism , Molecular Imaging , Multiple Sclerosis/diagnostic imaging , Multiple Sclerosis/enzymology , Acetylcholinesterase/metabolism , Aged , Autoradiography , Case-Control Studies , Female , Gray Matter/diagnostic imaging , Gray Matter/pathology , Humans , Male , Middle Aged , Multiple Sclerosis/pathology , Phenylcarbamates/chemistry , White Matter/diagnostic imaging , White Matter/pathologyABSTRACT
Deimination (or citrullination) is a post-translational modification catalyzed by a calcium-dependent enzyme family of five peptidylarginine deiminases (PADs). Deimination is involved in physiological processes (cell differentiation, embryogenesis, innate and adaptive immunity, etc.) and in autoimmune diseases (rheumatoid arthritis, multiple sclerosis and lupus), cancers and neurodegenerative diseases. Intermediate filaments (IF) and associated proteins (IFAP) are major substrates of PADs. Here, we focus on the effects of deimination on the polymerization and solubility properties of IF proteins and on the proteolysis and cross-linking of IFAP, to finally expose some features of interest and some limitations of citrullinomes.
Subject(s)
Arthritis, Rheumatoid/enzymology , Intermediate Filament Proteins/metabolism , Intermediate Filaments/enzymology , Multiple Sclerosis/enzymology , Neoplasms/enzymology , Neurodegenerative Diseases/enzymology , Protein Processing, Post-Translational , Protein-Arginine Deiminases/metabolism , Arthritis, Rheumatoid/genetics , Arthritis, Rheumatoid/immunology , Arthritis, Rheumatoid/pathology , Cell Differentiation , Citrullination , Epithelial Cells/enzymology , Epithelial Cells/pathology , Filaggrin Proteins , Humans , Intermediate Filament Proteins/chemistry , Intermediate Filament Proteins/genetics , Intermediate Filaments/ultrastructure , Mesenchymal Stem Cells/enzymology , Mesenchymal Stem Cells/pathology , Multiple Sclerosis/genetics , Multiple Sclerosis/immunology , Multiple Sclerosis/pathology , Neoplasms/genetics , Neoplasms/immunology , Neoplasms/pathology , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/immunology , Neurodegenerative Diseases/pathology , Neurons/enzymology , Neurons/pathology , Protein Multimerization , Protein-Arginine Deiminases/chemistry , Protein-Arginine Deiminases/genetics , Proteolysis , SolubilityABSTRACT
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that leads to progressive neurological disability due to axonal deterioration. Although MS presents profound heterogeneity in the clinical course, its underlying central mechanism is active demyelination and neurodegeneration associated with inflammation. Multiple autoimmune and neuroinflammatory pathways are involved in the demyelination process of MS. Analysis of MS lesions has shown that inflammatory genes are upregulated. Glycogen synthase kinase-3 (GSK-3) is part of the mitogen-activated protein kinase (MAPK) family and has important roles in many signaling cascades. GSK-3 is a highly conserved serine/threonine protein kinase expressed in both the central and the peripheral nervous systems. GSK-3 modulates several biological processes through phosphorylation of protein kinases, including cell signaling, neuronal growth, apoptosis and production of pro-inflammatory cytokines and interleukins, allowing adaptive changes in events such as cellular proliferation, migration, inflammation, and immunity. GSK-3 occurs in mammals in two isoforms GSK-3α and GSK-3ß, both of which are common in the brain, although GSK-3α is found particularly in the cerebral cortex, cerebellum, striated hippocampus and Purkinje cells, while GSK-3ß is found in all brain regions. In patients with chronic progressive MS, expression of GSK-3ß is elevated in several brain regions such as the corpus callosum and cerebral cortex. GSK-3ß inhibition may play a role in glial cell activation, reducing pathological pain induced by nerve injury by formalin injection. According to the role of GSK-3ß in pathological conditions, the aim of this article is review of the role of GSK-3ß in multiple sclerosis and inflammation of neurons.
Subject(s)
Brain/enzymology , Glycogen Synthase Kinase 3 beta/metabolism , Multiple Sclerosis/enzymology , Wnt Signaling Pathway , Animals , Anti-Inflammatory Agents/therapeutic use , Brain/drug effects , Brain/immunology , Brain/physiopathology , Glycogen Synthase Kinase 3 beta/antagonists & inhibitors , Humans , Inflammation Mediators/metabolism , Molecular Targeted Therapy , Multiple Sclerosis/drug therapy , Multiple Sclerosis/immunology , Multiple Sclerosis/physiopathology , Protein Kinase Inhibitors/therapeutic use , Up-Regulation , Wnt Signaling Pathway/drug effectsABSTRACT
Polyamines (i.e., putrescine, spermidine, and spermine) are bioactive polycations capable of binding nucleic acids and proteins and modulating signaling pathways. Polyamine functions have been studied most extensively in tumors, where they can promote cell transformation and proliferation. Recently, spermidine was found to exert protective effects in an experimental model of multiple sclerosis (MS) and to confer immunoregulatory properties on dendritic cells (DCs), via the indoleamine 2,3-dioxygenase 1 (IDO1) enzyme. IDO1 converts l-tryptophan into metabolites, collectively known as kynurenines, endowed with several immunoregulatory effects via activation of the arylhydrocarbon receptor (AhR). Because AhR activation increases polyamine production, the emerging scenario has identified polyamines and kynurenines as actors of an immunoregulatory circuitry with potential implications for immunotherapy in autoimmune diseases and cancer.
Subject(s)
Autoimmune Diseases , Immunomodulation , Kynurenine , Multiple Sclerosis , Polyamines , Animals , Autoimmune Diseases/immunology , Disease Models, Animal , Humans , Immunomodulation/immunology , Kynurenine/immunology , Multiple Sclerosis/enzymology , Multiple Sclerosis/immunology , Polyamines/immunology , Signal TransductionSubject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Multiple Sclerosis/drug therapy , Protein Kinase Inhibitors/therapeutic use , Agammaglobulinaemia Tyrosine Kinase/metabolism , Animals , Drug Design , Humans , Multiple Sclerosis/enzymology , Multiple Sclerosis/physiopathology , Protein Kinase Inhibitors/pharmacologyABSTRACT
INTRODUCTION: B cells have increasingly come under the spotlight as mediators of inflammatory central nervous system (CNS) demyelinating diseases such as multiple sclerosis (MS). B cell depletion via the targeting of the surface molecule CD20 has proven to be highly effective; however, continuous absence of an integral component of the immune system may cause safety concerns over time. Declining humoral competence and potential immune system impairments are key issues, and moreover, unselective removal of B cells reduces immune system control functions which should preferably be maintained in inflammatory CNS disease. AREAS COVERED: This paper illuminates the novel approach of specific interference with B cell signaling by targeting Bruton´s tyrosine kinase (BTK). We discuss the role of BTK within the B cell receptor (BCR) signaling cascade and BTK inhibition as a promising strategy to control inflammatory CNS disease which crucially excludes immune-cell depletion. We searched PubMed or clinicaltrials.gov for the terms 'BTK inhibition' or 'Bruton´s Tyrosine Kinase' or 'anti-CD20' and 'Multiple Sclerosis'. EXPERT OPINION: BTK inhibition has shown effectiveness in preclinical models of CNS disease and MS clinical trials. Further studies are necessary to differentiate this approach from B cell depletion and to position it in the armamentarium of therapeutics.
Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Multiple Sclerosis/drug therapy , Protein Kinase Inhibitors/pharmacology , Animals , B-Lymphocytes/metabolism , Humans , Multiple Sclerosis/enzymology , Multiple Sclerosis/physiopathology , Receptors, Antigen, B-Cell/metabolism , Signal Transduction/drug effectsABSTRACT
N-Acylethanolamine acid amidase (NAAA) deactivates the endogenous peroxisome proliferator-activated receptor-α (PPAR-α) agonist palmitoylethanolamide (PEA). NAAA-regulated PEA signaling participates in the control of peripheral inflammation, but evidence suggests also a role in the modulation of neuroinflammatory pathologies such as multiple sclerosis (MS). Here we show that disease progression in the mouse experimental autoimmune encephalomyelitis (EAE) model of MS is accompanied by induction of NAAA expression in spinal cord, which in presymptomatic animals is confined to motor neurons and oligodendrocytes but, as EAE progresses, extends to microglia/macrophages and other cell types. As previously reported for NAAA inhibition, genetic NAAA deletion delayed disease onset and attenuated symptom intensity in female EAE mice, suggesting that accrued NAAA expression may contribute to pathology. To further delineate the role of NAAA in EAE, we generated a mouse line that selectively overexpresses the enzyme in macrophages, microglia and other monocyte-derived cells. Non-stimulated alveolar macrophages from these NaaaCD11b+ mice contain higher-than-normal levels of inducible nitric oxide synthase and display an activated morphology. Furthermore, intranasal lipopolysaccharide injections cause greater alveolar leukocyte accumulation in NaaaCD11b+ than in control mice. NaaaCD11b+ mice also display a more aggressive clinical response to EAE induction, compared to their wild-type littermates. The results identify NAAA as a critical control step in EAE pathogenesis, and point to this enzyme as a possible target for the treatment of MS.
Subject(s)
Amidohydrolases/metabolism , Encephalomyelitis, Autoimmune, Experimental/enzymology , Encephalomyelitis, Autoimmune, Experimental/pathology , Multiple Sclerosis/enzymology , Multiple Sclerosis/pathology , Amidohydrolases/genetics , Animals , Disease Progression , Female , Lipopolysaccharides , Macrophages/enzymology , Male , Mice , Mice, Inbred C57BL , Microglia/enzymology , Motor Neurons/enzymology , Nitric Oxide Synthase Type II/biosynthesis , Nitric Oxide Synthase Type II/genetics , Oligodendroglia/metabolism , Spinal Cord/enzymologyABSTRACT
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system in young adults. Heparan sulfate proteoglycans (HSPGs) are ubiquitous to the cell surface and the extracellular matrix. HSPG biosynthesis is a complex process involving enzymatic attachment of heparan sulfate (HS) chains to a core protein. HS side chains mediate specific ligand and growth factor interactions directing cellular processes including cell adhesion, migration and differentiation. Two main families of HSPGs exist, the syndecans (SDC1-4) and glypicans (GPC1-6). The SDCs are transmembrane proteins, while the GPC family are GPI linked to the cell surface. SDC1 has well-documented interactions with numerous signalling pathways. Genome-wide association studies (GWAS) have identified regions of the genome associated with MS including a region on chromosome 13 containing GPC5 and GPC6. International studies have revealed significant associations between this region and disease development. The exostosin-1 (EXT1) and sulfatase-1 (SULF1) are key enzymes contributing to the generation of HS chains. EXT1, with documented tumour suppressor properties, is involved in the initiation and polymerisation of the growing HS chain. SULF1 removes 6-O-sulfate groups from HS chains, affecting protein-ligand interactions and subsequent downstream signalling with HS modification potentially having significant effects on MS progression. In this study, we identified significant associations between single nucleotide polymorphisms in SDC1, GPC5 and GPC6 and MS in an Australian Caucasian case-control population. Further significant associations in these genes were identified when the population was stratified by sex and disease subtype. No association was found for EXT1 or SULF1.
Subject(s)
Biomarkers/analysis , Genome-Wide Association Study , Heparan Sulfate Proteoglycans/chemistry , Multiple Sclerosis/pathology , Polymorphism, Single Nucleotide , White People/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Australia/epidemiology , Case-Control Studies , Female , Glypicans/genetics , Humans , Male , Middle Aged , Multiple Sclerosis/enzymology , Multiple Sclerosis/epidemiology , Multiple Sclerosis/genetics , N-Acetylglucosaminyltransferases/genetics , Sulfotransferases/genetics , Syndecan-1/genetics , Young AdultABSTRACT
Nanobodies have been progressively replacing traditional antibodies in various immunological methods. However, the use of nanobodies as capture antibodies is greatly hampered by their poor performance after passive adsorption to polystyrene microplates, and this restricts the full use of double nanobodies in sandwich enzyme-linked immunosorbent assays (ELISAs). Herein, using the human soluble epoxide hydrolase (sEH) as a model analyte, we found that both the immobilization format and the blocking agent have a significant influence on the performance of capture nanobodies immobilized on polystyrene and the subsequent development of double-nanobody sandwich ELISAs. We first conducted epitope mapping for pairing nanobodies and then prepared a horseradish-peroxidase-labeled nanobody using a mild conjugation procedure as a detection antibody throughout the work. The resulting sandwich ELISA using a capture nanobody (A9, 1.25 µg/mL) after passive adsorption and bovine serum albumin (BSA) as a blocking agent generated a moderate sensitivity of 0.0164 OD·mL/ng and a limit of detection (LOD) of 0.74 ng/mL. However, the introduction of streptavidin as a linker to the capture nanobody at the same working concentration demonstrated a dramatic 16-fold increase in sensitivity (0.262 OD·mL/ng) and a 25-fold decrease in the LOD for sEH (0.03 ng/mL). The streptavidin-bridged double-nanobody ELISA was then successfully applied to tests for recovery, cross-reactivity, and real samples. Meanwhile, we accidentally found that blocking with skim milk could severely damage the performance of the capture nanobody by an order of magnitude compared with BSA. This work provides guidelines to retain the high effectiveness of the capture nanobody and thus to further develop the double-nanobody ELISA for various analytes.
Subject(s)
Diabetes Mellitus/diagnosis , Enzyme-Linked Immunosorbent Assay , Epoxide Hydrolases/analysis , Leukocytes, Mononuclear/enzymology , Multiple Sclerosis/diagnosis , Diabetes Mellitus/enzymology , Epoxide Hydrolases/metabolism , Humans , Leukocytes, Mononuclear/pathology , Multiple Sclerosis/enzymologyABSTRACT
Multiple sclerosis (MS) is the most common autoimmune disease of the CNS. The etiology of MS is still unclear but it is widely recognized that both genetic and environmental factors contribute to its pathogenesis. Immune signaling and responses are critically regulated by ubiquitination, a posttranslational modification that is promoted by ubiquitinating enzymes and inhibited by deubiquitinating enzymes (DUBs). Genome-wide association studies (GWASs) identified that polymorphisms in or in the vicinity of two human DUB genes TNFAIP3 and USP18 were associated with MS susceptibility. Studies with experimental autoimmune encephalomyelitis (EAE), an animal model of MS, have provided biological rationale for the correlation between these DUBs and MS. Additional studies have shown that other DUBs are also involved in EAE by controlling distinct cell populations. Therefore, DUBs are emerging as crucial regulators of MS/EAE and might become potential therapeutic targets for the clinical treatment of MS.
Subject(s)
Autoimmunity/immunology , Deubiquitinating Enzymes/metabolism , Encephalomyelitis, Autoimmune, Experimental/enzymology , Multiple Sclerosis/enzymology , Animals , Encephalomyelitis, Autoimmune, Experimental/immunology , Humans , Multiple Sclerosis/immunologyABSTRACT
Chitinase 3-like 1 (CHI3L1) is known to play a role as prognostic biomarker in the early stages of multiple sclerosis (MS), and patients with high cerebrospinal fluid CHI3L1 levels have an increased risk for the development of neurological disability. Here, we investigated its potential neurotoxic effect by adding recombinant CHI3L1 in vitro to primary cultures of mouse cortical neurons and evaluating both neuronal functionality and survival by immunofluorescence. CHI3L1 induced a significant neurite length retraction after 24 and 48 hours of exposure and significantly reduced neuronal survival at 48 hours. The cytotoxic effect of CHI3L1 was neuron-specific and was not observed in mouse immune or other central nervous system cells. These results point to a selective neurotoxic effect of CHI3L1 in vitro and suggest a potential role of CHI3L1 as therapeutic target in MS patients.