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Oxidative stress plays a pivotal role in multiple sclerosis (MS), triggering demyelination predominantly through excessive peroxide production and the depletion of antioxidants. The accumulation of oxidative damage can be caused by dysregulation of astrocytes, which are the brain's main regulators of oxidative homeostasis. Calycosin, an essential bioactive component extracted from Astragalus, is recognized for its neuroprotective properties. Although recent research has highlighted calycosin's neuroprotective capabilities, its role in demyelinating conditions like MS remains unclear. In this work, we examined the possible molecular mechanism of calycosin's neuroprotective effect on cuprizone (CPZ)-induced demylination in mice. According to our research, calycosin successfully reduced demyelination and behavioral dysfuction in CPZ mice. Calycosin also decreased the production of oxidative stress and enhanced the expression of antioxidants in CPZ mice and in astrocytes induced by hydrogen peroxide (H 2 O 2 ). Furthermore, both in vivo and in vitro experiments demonstrated that calycosin promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) along with the upregulation of heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and superoxide dismutase (SOD). Importantly, the application of all-trans retinoic acid (ATRA), a specific inhibitor of Nrf2, effectively reversed the myelin-protective and antioxidant effects conferred by calycosin. This study suggested that calycosin might exert neuroprotection by inhibiting oxidative stress and reducing demyelination via the activation of astrocyte Nrf2 signaling. These findings indicated that calycosin might be a potential candidate for treating MS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The novel antidepressant arketamine, the (R)-enantiomer of ketamine, has been shown to ameliorate demyelination and facilitate remyelination in the brains of cuprizone (CPZ)-treated mice. However, the mechanisms behind its effects remain unclear. Given the role of transforming growth factor β1 (TGF-β1) in arketamine's antidepressant-like effects, we examined whether TGF-β1 also plays a role in arketamine's effects on demyelination and remyelination in CPZ-treated mice. Additionally, we investigated the effects of intranasal TGF-β1 on demyelination and remyelination in these mice. Repeated intermittent administration of arketamine (10 mg/kg/day, twice weekly for the last 2-weeks) attenuated demyelination in the corpus callosum (CC) of CPZ (6 weeks)-treated mice. Furthermore, pretreatment with RepSox (10 mg/kg/day), an inhibitor of the TGF-β receptor 1, significantly blocked the beneficial effects of arketamine on the demyelination in the CC of CPZ-treated mice. Additionally, repeated intermittent administration of TGF-β1 (3.0 μg/kg/day, twice weekly for 2 weeks) significantly ameliorated demyelination and facilitated remyelination in the CC of CPZ-treated mice. These data suggest that arketamine can mitigate demyelination and facilitates remyelination in the brains of CPZ-treated mice through a TGF-β1-dependent mechanism., Competing Interests: Declaration of competing interest Dr. Hashimoto is the inventor of filed patent applications on “The use of R-ketamine in the treatment of psychiatric diseases”, “(S)-norketamine and salt thereof as pharmaceutical”, “R-ketamine and derivative thereof as prophylactic or therapeutic agent for neurodegeneration disease or recognition function disorder”, “Preventive or therapeutic agent and pharmaceutical composition for inflammatory diseases or bone diseases”, and “R-ketamine and its derivatives as a preventive or therapeutic agent for a neurodevelopmental disorder” by the Chiba University. Dr. Hashimoto has also received speakers’ honoraria, consultant fee, or research support from Otsuka. Other authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

The research aims to study the therapeutic impact of HEK293-XPack-Olig2 cell-derived exosomes on remyelination of the corpus callosum in a cuprizone-induced demyelinating disease model. A lentiviral vector expressing Olig2 was constructed using XPack technology. The highly abundant Olig2 exosomes (ExoOs) were isolated by centrifugation for subsequent experiments. Western blot, nanoparticle tracking analysis (NTA), and electron microscopy showed no significant difference in particle size and morphology between Exos and ExoOs, and a high level of Olig2 expression could be detected in ExoOs, indicating that exosome modification by XPack technology was successful. The Black Gold/Fluromyelin staining analysis showed that the ExoOs group significantly reduced the demyelination area in the corpus callosum compared to the PBS and Exos groups. Additionally, the PDGFRα/APC staining of the demyelinating region revealed an increase in APC + oligodendrocytes and a decrease in PDGFRα + oligodendrocyte progenitor cells (OPCs) in the ExoOs group. Furthermore, there was evident myelin regeneration in the demyelinated areas after ExoOs treatment, with better g-ratio and a higher number of intact myelin compared to the other treatment groups. The level of Sox10 expression in the brain tissue of the ExoOs group were higher compared to those of the PBS and Exos groups. The demyelination process can be significantly slowed down by the XPack-modified exosomes, the differentiation of OPCs promoted, and myelin regeneration accelerated under pathological conditions. This process is presumed to be achieved by changing the expression level of intracellular differentiation-related genes after exosomes transport Olig2 enriched into oligodendrocyte progenitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

Multiple sclerosis (MS) is a complex autoimmune and neurodegenerative disorder that affects the central nervous system (CNS). It is characterized by a heterogeneous disease course involving demyelination and inflammation. In this study, we utilized two distinct animal models, cuprizone (CPZ)-induced demyelination and experimental autoimmune encephalomyelitis (EAE), to replicate various aspects of the disease. We aimed to investigate the differential CNS responses by examining the proteomic profiles of EAE mice during the peak disease (15 days post-induction) and cuprizone-fed mice during the acute phase (38 days). Specifically, we focused on two different regions of the CNS: the dorsal cortex (Cx) and the entire spinal cord (SC). Our findings revealed varied glial, synaptic, dendritic, mitochondrial, and inflammatory responses within these regions for each model. Notably, we identified a single protein, Orosomucoid-1 (Orm1), also known as Alpha-1-acid glycoprotein 1 (AGP1), that consistently exhibited alterations in both models and regions. This study provides insights into the similarities and differences in the responses of these regions in two distinct demyelinating models., (Copyright © 2023 IBRO. Published by Elsevier Ltd. All rights reserved.)

Multiple sclerosis (MS) is a complex and multifactorial neurodegenerative disease with unknown etiology, MS is featured by multifocal demyelinated lesions distributed throughout the brain. It is assumed to result from an interaction between genetic and environmental factors, including nutrition. Therefore, different therapeutic approaches are aiming to stimulate remyelination which could be defined as an endogenous regeneration and repair of myelin in the central nervous system. Carvedilol is an adrenergic receptor antagonist. Alpha lipoic acid (ALA) is a well-known antioxidant. Herein, we investigated the remyelination potential of Carvedilol or ALA post-Cuprizone (CPZ) intoxication. Carvedilol or ALA (20 mg/kg/d) was administrated orally for two weeks at the end of the five weeks of CPZ (0.6%) administration. CPZ provoked demyelination, enhanced oxidative stress, and stimulated neuroinflammation. Histological investigation of CPZ-induced brains showed obvious demyelination in the corpus callosum (CC). Both Carvedilol and ALA demonstrated remyelinating activities, with corresponding upregulation of the expression of MBP and PLP, the major myelin proteins, downregulation of the expression of TNF-α and MMP-9, and decrement of serum IFN-γ levels. Moreover, both Carvedilol and ALA alleviated oxidative stress, and ameliorated muscle fatigue. This study highlights the neurotherapeutic potential of Carvedilol or ALA in CPZ-induced demyelination, and offers a better model for the exploring of neuroregenerative strategies. The current study is the first to demonstrate a pro-remyelinating activity for Carvedilol, as compared to ALA, which might represent a potential additive benefit in halting demyelination and alleviating neurotoxicity. However, we could declare that Carvedilol showed a lower neuroprotective potential than ALA., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Demyelinating diseases of the central nervous system are characterized by recurrent demyelination and progressive neurodegeneration, but there are no clinical drugs targeting myelin regeneration or improving functional disability in the treatment of multiple sclerosis. Total flavone of Epimedium (TFE) is the main active components of Epimedium, which exhibits the beneficial biological activities in the treatment of diseases, but there is no report in the treatment of demyelinating disorder. The purpose of this study was to explore the therapeutic potential and possible mechanism of TFE in the treatment of demyelination. The results showed that TFE efficiently improved the behavioural performance and histological demyelination in cuprizone (CPZ)-induced demyelinating model. In terms of action, TFE increased astrocytes enrichment in corpus callosum, striatum and cortex, and promoted astrocytes to express neurotrophic factors. Furthermore, the expression of platelet-activating factor receptor (PAFR) in astrocytes was induced by CPZ feeding and LPS stimulation, accompanied by the increase of inflammatory cytokines TNF-α,IL-6 and IL-1β. TFE declined the expression of PAFR, and inhibited inflammatory response. At the same time, TFE also antagonized PAFR activation and inflammatory response triggered by PAF, which further confirmed that TFE, as a new PAFR antagonist, inhibited the astrocyte-derived inflammatory response by antagonizing PAFR-neuroinflammation axis, thus contributing to myelin protection and regeneration., (Copyright © 2021. Published by Elsevier B.V.)

Multiple sclerosis (MS) is one of the most common neurodegenerative diseases. In this disease, the immune system attacks oligodendrocyte cells and the myelin sheath of myelinated neurons in the central nervous system, causing their destruction. These conditions lead to impaired conduction of nerve impulses and are manifested by symptoms such as weakness, fatigue, visual and motor disorders. This study aimed to evaluate the ability of trifluoperazine (TF) to improve cuprizone-induced behavioral and histopathological changes in the prefrontal cortex of C57BL/6 male mice. Demyelination was induced by adding 0.2% cuprizone (CPZ) to the standard animal diet for 6 weeks. Three doses of TF (0.5, 1 and 2 mg/kg/day; i.p.) were given once daily for the last 2 weeks of treatment. Treatment with CPZ induced a weight loss during 6 weeks of treatment compared to the control group, which was reversed by the administration of TF. Behavioral tests (pole test and rotarod performance test) showed a decrease in motor coordination and balance in the group treated with CPZ (P < 0.01). Treatment with TF during the last two weeks was able to improve these motor deficiencies. Histopathological examination also evidenced an increase in demyelination in the CPZ group, which was improved by TF administration. In addition, CPZ intake significantly decreased the cerebral cortex levels of p-Nrf2 (P < 0.001) and increased the levels of p-IKB (P < 0.001) and, these changes were normalized in the TF groups. TF administration also reversed the increased levels of nitrite and the reduced activity of the antioxidant enzyme superoxide dismutase associated with CPZ exposure. TF can to reduce the harmful effects of CPZ by reducing the demyelination and modulating the Nrf2 and NF-kB signaling pathways., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study aimed at testing the hypothesis that treatment with icariin (ICA, a type of flavonoid) could mitigate the cuprizone (CPZ)-induced acute demyelination in the brain of mice and the potential mechanisms. Female C57BL/6J mice were fed continually with regular rodent chow or the chow supplemented with CPZ (0.2 % w/w) for six weeks to induce acute demyelination. The CPZ-fed mice were treated with vehicle or ICA at 12.5 or 25 mg/kg beginning at three weeks post CPZ feeding daily for three weeks. Their brain tissue sections were stained with oil red O, luxol-fast blue (LFB) and immunohistochemistry to characterize the levels of brain demyelination, myelin basic protein (MBP) and brain-derived neurotrophic factor (BDNF) and the numbers of oligodendrocytes (Ols), oligodendrocyte progenitor cells (OPCs), microglia and astrocytes in mice. Compared with the healthy controls, CPZ feeding caused the brain demyelination by increasing NG2 + OPCs, but decreased oil red O and LFB staining, MBP level and GST-pi + Ols in the brain corpus callosum region of mice. Furthermore, CPZ feeding decreased the number of BDNF + cells in the brain cortex and hippocampus regions, but increased microglia in the brain corpus callosum, cortex and caudate putamen, and astrocytes in the corpus callosum regions of mice. Treatment with ICA significantly mitigated or abrogated the toxic demyelination of CPZ by preserving MBP and BDNF proteins and modulating the numbers of Ols, OPCs, microglia and astrocytes in the brain of mice. ICA treatment significantly ameliorated the CPZ-mediated demyelination and modulated the number of Ols, microglia and astrocytes in the brain of mice., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Recent studies have emphasized that adult hippocampal neurogenesis impairment may be associated with cognitive problems. Because cuprizone (CPZ), a copper-chelating reagent, was shown to decrease the production of new neurons, we aimed to further understand the involvement of adult hippocampal neurogenesis impairment in cognitive function by using a short-term (2-week) CPZ exposure paradigm. The CPZ-fed mice showed cognitive deficits, i.e., impaired sensorimotor gating and reduced social novelty preference, compared to normal-fed mice. Although a long-term (e.g., 5-week) CPZ exposure paradigm was found to cause demyelination, we encountered that the labeling for myelin in the hippocampus was unaffected by 2-week CPZ exposure. The densities of neuronal progenitor cells (NPCs) and newborn granule cells (NGCs) were lower in CPZ-fed mice than in normal-fed mice, while those of neural stem cells (NSCs) were comparable between groups. We then examined whether short-term CPZ exposure might induce activation of signal transducer and activator of transcription 3 (STAT3), which plays a major role in cytokine receptor signaling. The densities of phosphorylated STAT3-positive (pSTAT3 + ) NSCs were higher in CPZ-fed mice than in normal-fed mice, while those of pSTAT3 + NPCs/NGCs were very low in both groups. Interestingly, the densities of bromodeoxyuridine-positive (BrdU + ) NSCs were higher in CPZ-fed mice than in normal-fed mice 2 weeks after BrdU injection, while those of BrdU + NPCs/NGCs were lower in CPZ-fed mice than in normal-fed mice. These findings suggest that short-term CPZ exposure inhibits differentiation of NSCs into NPCs via activation of STAT3, which may in part underlie cognitive deficits., Competing Interests: Conflict of Interest Statement The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2021 IBRO. Published by Elsevier Ltd. All rights reserved.)

The metalloproteinase ADAM10 is the most important amyloid precursor protein (APP) α-secretase, preventing the deposit of neurotoxic amyloid β (Aβ) peptide and generating a soluble APP fragment (sAPP α ) with neurotrophic functions. Recent studies have suggested that ADAM10 also play a role in the pathogenesis of inflammatory CNS diseases, such as multiple sclerosis (MS). Demyelination is the hallmarks of MS but the mechanisms involved remain unclear. Here in this study, we examined the role that ADAM10 might play in the cuprizone-induced demyelination model. Our results demonstrated that ADAM10 expression and sAPP α production were significantly reduced in the corpus callosum in response to cuprizone treatment. Overexpression of ADAM10 increased sAPP α production and suppressed demyelination as well as neuroinflammation and oxidative stress in cuprizone-induced demyelination model. Pharmacological inhibition of ADAM10 activity, however, abrogates the protective effect of ADAM10 against demyelination, neuroinflammation and oxidative stress. It has been reported that CNS demyelination may induce seizure activity. Here, we found that overexpression of ADAM10 reduced seizure susceptibility in cuprizone-induced demyelination model, suggesting that ADAM10-derived sAPP α suppresses demyelination and reduces seizure susceptibility via ameliorating neuroinflammation and oxidative stress in cuprizone-induced demyelination model., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Estrogen produces a beneficial role in animal models of multiple sclerosis (MS). The effect of 17β-estradiol therapy on microglia polarization and neuroinflammation in the corpus callosum of the cuprizone-induced demyelination model has not been elucidated. In this study, mice were given 0.2% cuprizone (CPZ) for 5 weeks to induce demyelination during which they received 50 ng of 17β-estradiol (EST), injected subcutaneously in the neck region, twice weekly. Data revealed that treatment with 17β-estradiol therapy (CPZ+EST) improved neurological behavioral deficits, displayed by a significant reduction in escape latencies, in comparison to untreated CPZ mice. Also, administration of 17β-estradiol caused a decrease in demyelination levels and axonal injury, as demonstrated by staining with Luxol fast blue, immunofluorescence to myelin basic protein, and transmission electron microscopy analysis. In addition, at the transcriptional level in the brain, mice treated with 17β-estradiol (CPZ+EST) showed a decrease in the levels of M1-assosicted microglia markers (CD86, iNOS and MHC-II) whereas M2-associated genes (Arg-1, CD206 and Trem-2) were increased, compared to CPZ mice. Moreover, administration of 17β-estradiol resulted in a significant reduction (∼3-fold) in transcript levels of NLRP3 inflammasome and its downstream product IL-18, compared to controls. In summary, this study demonstrated for the first time that exogenous 17β-estradiol therapy robustly leads to the reduction of M1 phenotype, stimulation of polarized M2 microglia, and repression of NLRP3 inflammasome in the corpus callosum of CPZ demyelination model of MS. The positive effects of 17β-estradiol on microglia and inflammasome seems to facilitate and accelerate the remyelination process., (Copyright © 2021 IBRO. Published by Elsevier Ltd. All rights reserved.)

Demyelination is a well-known pathological process in CNS disorders such as multiple sclerosis (MS). It provokes progressive axonal degeneration and functional impairments and no efficient therapy is presently available to combat such insults. Recently, we have shown that etazolate, a pyrazolopyridine compound and an α-secretase activator, was able to promote myelin protection and remyelination after cuprizone (CPZ)-induced acute demyelination in C57Bl/6 mice. In continuation of this work, here we have further investigated the effects of etazolate treatment after acute cuprizone-induced demyelination at the molecular level (expression of myelin genes Plp, Mbp and Mag and inflammatory markers Il-1β, Tnf-α) and at the functional level (locomotor and spatial memory skills) in vivo. To this end, we have employed two protocols which consists of administering etazolate (10 mg/kg/d) for a period of 2 weeks either during (Protocol #1) or after (Protocol #2) 5-weeks of CPZ-induced demyelination. At the molecular level, we observed that CPZ intoxication altered inflammatory and myelin gene expression and it was not restored with either of the etazolate treatment protocols. At the functional level, the locomotor activity was impaired after 3-weeks of CPZ intoxication (Protocol #1) and our data indicates a modest but beneficial effect of etazolate treatment. Spatial memory evaluated was not affected either by CPZ intake or etazolate treatment in both protocols. Altogether, this study shows that the beneficial effect of etazolate upon demyelination does not occur at the gene expression level at the time points studied. Furthermore, our results also highlight the difficulty in revealing functional sequelae following CPZ intoxication., (Copyright © 2020 IBRO. Published by Elsevier Ltd. All rights reserved.)

The mechanism of demyelinating diseases is controversial, while demyelination and remyeliantion disorder is the acknowledged etiology and therapeutic target. Untill now, there is no efficient therapy for these diseases. CZ-7, a new derivative of Claulansine F, which has been reported before, were investigated its pro-remyelination effect and its associated mechanism in cuprizone (CPZ)-induced demyelination model. In this study, male C57BL/6 mice were subjected to CPZ (300 mg/kg) through intragastric gavage and were orally administered CZ-7 (20 mg/kg) meanwhile. The results of weight monitoring and behavioral testing showed that CZ-7 can significantly improve behavior dysfunction in the demyelinating mice. Luxol-fast blue (LFB) staining, myelin basic protein (MBP) immunostaining, transmission electron microscopy (TEM) and QPCR results indicated the therapeutic effect of CZ-7 on CPZ mice model. Furthermore, degraded myelin basic protein (dMBP) immunofluorescent staining and oil red O staining showed that CZ-7 contributed to the clearance of degraded myelin debris. More microglia displayed phagocytic shape assembled in corpus callosum (CC) and there was an active process of phagocytosis in microglia after CZ-7 treatment. Immunofluorescent staining and QPCR analysis revealed the M2-polarized phenotype switch of microglia in the process of myelin debris removel, which demostrated the microenvironment improvement of CZ-7. Moreover, immunofluorescent staining of NG2 and O4 demonstated that more oligodendrocyte precursor cells (OPCs) existed in CC after CZ-7 treatment. In conclusion, our results demonstrated CZ-7 has a potential therapeutic effect for MS and other demyelinating diseases through enhancing myelin debris clearance to improve the microenvironment., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflicts of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Biological inflammation induced during penetrating cortical injury can disrupt functional neuronal and glial activity within the cortex, resulting in potential recording failure of chronically implanted neural interfaces. Oligodendrocytes provide critical support for neuronal health and function through direct contact with neuronal soma and axons within the cortex. Given their fundamental role to regulate neuronal activity via myelin, coupled with their heightened vulnerability to metabolic brain injury due to high energetic demands, oligodendrocytes are hypothesized as a possible source of biological failure in declining recording performances of intracortical microelectrode devices. To determine the extent of their contribution to neuronal activity and function, a cuprizone-inducible model of oligodendrocyte depletion and demyelination in mice was performed prior to microelectrode implantation. At 5 weeks of cuprizone exposure, mice demonstrated significantly reduced cortical oligodendrocyte density and myelin expression. Mice were then implanted with functional recording microelectrodes in the visual cortex and neuronal activity was evaluated up to 7 weeks alongside continued cuprizone administration. Cuprizone-induced oligodendrocyte loss and demyelination was associated with significantly reduced recording performances at the onset of implantation, which remained relatively stable over time. In contast, recording performances for mice on a normal diet were intially elevated before decreasing over time to the recording level of tcuprizone-treated mice. Further electrophysiological analysis revealed deficits in multi-unit firing rates, frequency-dependent disruptions in neuronal oscillations, and altered laminar communication within the cortex of cuprizone-treated mice. Post-mortem immunohistochemistry revealed robust depletion of oligodendrocytes around implanted microelectrode arrays alongside comparable neuronal densities to control mice, suggesting that oligodendrocyte loss was a possible contributor to chronically impaired device performances. This study highlights potentially significant contributions from the oligodendrocyte lineage population concerning the biological integration and long-term functional performance of neural interfacing technology., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Cuprizone administration in mice leads to oligodendrocyte death and demyelination. The effect is thought to reflect copper-chelation that leads to inhibition of complex IV of the mitochondrial respiratory chain. The effects this drug has on neurons are less well known., Objective: To investigate the toxic effects of cuprizone on mitochondria in neurons., Methods: Male c57Bl/6 mice were fed 0.2% cuprizone for up to 5 weeks. Cuprizone-fed and control mice were examined at week 1, 3, 5 and 4 weeks after cessation of cuprizone exposure. The brain was examined for myelin, complex I, complex IV and for COX/SDH activities. Mitochondrial-DNA was investigated for deletions and copy number variation., Results: We found decreased levels of complex IV in the cerebellar Purkinje neurons of mice exposed to cuprizone. This decrease was not related to a general decrease in mitochondrial volume or mass, as there were no differences in the levels of complex I or TOMM20., Conclusion: Neurons are affected by cuprizone-treatment. Whether this mitochondrial dysfunction acts as a subclinical trigger for demyelination and the long-term axonal degeneration that proceeds after cuprizone treatment stops remains unclear., (Copyright © 2019 Elsevier B.V. and Mitochondria Research Society. All rights reserved.)

Sulfasalazine (SF) promotes remyelination and improves the outcome of multiple sclerosis (MS) patients. However, the underlining mechanism remains elusive. Here, we examined whether SF blocks microglia switching to a pro-inflammatory M1-like phenotype through a competing endogenous RNA (ceRNA) effects in cuprizone-induced demyelination. The microglia reprogramming effects of SF in the mice model of cuprizone-induced demyelination was measured by histological, immunohistochemical and molecular biological methods. We also measured the effects of the condition media from SF-treated microglia on the differentiation of OLN-93 cells. Insights of the mechanism of ceRNAs of miR-136-5p and long non-coding RNA (lncRNA) HOTAIR were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation. Microglia switched to a pro-inflammatory M1-like phenotype in cuprizone induced-demyelination. Conversely, SF inhibited the M1-like polarization with the increased remyelination which was attenuated by microglia depletion. SF inhibited production of M1-like factors TNF-α and INF-γ in microglia, and thereby promoted the differentiation of OLN-93 oligodendrocytes. SF down-regulated lncRNA HOTAIR but up-regulated miR-136-5p, and thus inactivated AKT2-NF-κB in cuprizone-treated microglia. Importantly, lncRNA HOTAIR overexpression reversed the increased miR-136-5p expression by SF and thereby attenuated the inhibition of AKT2-mediated NF-κB activation. Mimic of miR-136-5p inhibited cuprizone-induced activation of AKT2-NF-κB in the microglia. In summary, SF blocks microglia switching to a pro-inflammatory M1-like phenotype by ceRNA effect of miR-136-5p and lncRNA HOTAIR in cuprizone-induced demyelination. Our findings show the therapeutic potential of SF for human MS probably by targeting epigenetic regulation in microglia., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Degradation of myelin sheath is thought to be the cause of neurodegenerative diseases, such as multiple sclerosis (MS), but definitive agreement on the mechanism of how myelin is lost is currently lacking. Autoimmune initiation of MS has been recently questioned by proposing that the immune response is a consequence of oligodendrocyte degeneration. To study the process of myelin breakdown, we induced demyelination with cuprizone and applied coherent anti-Stokes Raman scattering (CARS) microscopy, a non-destructive label-free method to image lipid structures in living tissue. We confirmed earlier results showing a brain region dependent myelin destructive effect of cuprizone. In addition, high resolution in situ CARS imaging revealed myelin debris forming lipid droplets alongwith myelinated axon fibers. Quantification of lipid debris with custom-made software for segmentation and three dimensional reconstruction revealed brain region dependent accumulation of lipid drops inversely correlated with the thickness of myelin sheaths. Finally, we confirmed that in situ CARS imaging is applicable to living human brain tissue in brain slices derived from a patient. Thus, CARS microscopy is potent tool for quantitative monitoring of myelin degradation in unprecedented spatiotemporal resolution during oligodendrocyte damage. We think that the accumulation of lipid drops around degrading myelin might be instrumental in triggering subsequent inflammatory processes., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Demyelination of the central nervous system (CNS) has been associated to reactive microglia in neurodegenerative disorders, such as multiple sclerosis (MS). The M1 microglia phenotype plays a pro-inflammatory role while M2 is involved in anti-inflammatory processes in the brain. In this study, CPZ-induced demyelination mouse model was used to investigate the effect of progesterone (PRO) therapy on microglia activation and neuro-inflammation. Results showed that progesterone therapy (CPZ+PRO) decreased neurological behavioral deficits, as demonstrated by significantly decreased escape latencies, in comparison to CPZ mice. In addition, CPZ+PRO caused a significant reduction in the mRNA expression levels of M1-markers (iNOS, CD86, MHC-II and TNF-α) in the corpus callosum region, whereas the expression of M2-markers (Trem-2, CD206, Arg-1 and TGF-β) was significantly increased, in comparison to CPZ mice. Moreover, CPZ+PRO resulted in a significant decrease in the number of iNOS + and Iba-1 + /iNOS + cells (M1), whereas TREM-2 + and Iba-1 + /TREM-2 + cells (M2) significantly increased, in comparison to CPZ group. Furthermore, CPZ+PRO caused a significant decrease in mRNA and protein expression levels of NLRP3 and IL-18 (~2-fold), in comparison to the CPZ group. Finally, CPZ+PRO therapy was accompanied with reduced levels of demyelination, compared to CPZ, as confirmed by immunofluorescence to myelin basic protein (MBP) and Luxol Fast Blue (LFB) staining, as well as transmission electron microscopy (TEM) analysis. In summary, we reported for the first time that PRO therapy causes polarization of M2 microglia, attenuation of M1 phenotype, and suppression of NLRP3 inflammasome in a CPZ-induced demyelination model of MS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

GPR37 is an orphan G protein-coupled receptor that is predominantly expressed in the brain and found at particularly high levels in oligodendrocytes. GPR37 has been shown to exert effects on oligodendrocyte differentiation and myelination during development, but the molecular basis of these actions is incompletely understood and moreover nothing is known about the potential role(s) of this receptor under demyelinating conditions. To shed light on the fundamental biology of GPR37, we performed proteomic studies comparing protein expression levels in the brains of mice lacking GPR37 and its close relative GPR37-like 1 (GPR37L1). These studies revealed that one of the proteins most sharply decreased in the brains of Gpr37/Gpr37L1 double knockout mice is the myelin-associated glycoprotein MAG. Follow-up Western blot studies confirmed this finding and demonstrated that genetic deletion of Gpr37, but not Gpr37L1, results in strikingly decreased brain expression of MAG. Further in vitro studies demonstrated that GPR37 and MAG form a complex when expressed together in cells. As loss of MAG has previously been shown to result in increased susceptibility to brain insults, we additionally assessed Gpr37-knockout (Gpr37 - / - ) vs. wild-type mice in the cuprizone model of demyelination. These studies revealed that Gpr37 - / - mice exhibit dramatically increased loss of myelin in response to cuprizone, yet do not show any increased loss of oligodendrocyte precursor cells or mature oligodendrocytes. These findings reveal that loss of GPR37 alters oligodendrocyte physiology and increases susceptibility to demyelination, indicating that GPR37 could be a potential drug target for the treatment of demyelinating diseases such as multiple sclerosis., (Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.)

Multiple sclerosis is a chronic demyelinating disease of the central nervous system leading to progressive cognitive and motor dysfunction, which is characterized by neuroinflammation, demyelination, astrogliosis, loss of oligodendrocytes, and axonal pathologies. Cyclic phosphatidic acid (cPA) is a naturally occurring phospholipid mediator with a unique cyclic phosphate ring structure at the sn-2 and sn-3 positions of the glycerol backbone. cPA elicits a neurotrophin-like action and protects hippocampal neurons from ischemia-induced delayed neuronal death. In this study, we investigated the effects of cPA on cuprizone-induced demyelination, which is a model of multiple sclerosis. Mice were fed a diet containing 0.2% cuprizone for 5 weeks, which induces severe demyelination, astrocyte and microglial activation, and motor dysfunction. Simultaneous administration of cPA effectively attenuated cuprizone-induced demyelination, glial activation, and motor dysfunction. These data indicate that cPA may be a useful treatment to reduce the extent of demyelination and the severity of motor dysfunction in multiple sclerosis. cPA is a potential lead compound in the development of drugs for the treatment of this devastating disease., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The mammalian subventricular zone (SVZ) is the largest germinative zone of the adult brain. Progenitor cells generated from the SVZ play important roles during the remyelination process. To determine the functional role of Olig2 in regulating astroglial differentiation in the mouse SVZ, we used the cuprizone mouse model to investigate demyelination. We found that cuprizone administration significantly enhanced the expression of Olig2 and increased astroglial differentiation in the SVZ, as compared with control. Moreover, cytoplasmic translocation of Olig2 occurred after demyelination. In vitro studies further revealed that supplementation of culture media with growth factors enhanced the oligodendroglial differentiation of oligodendrocyte progenitor cells (OPCs), whereas serum alone promoted astroglial differentiation and cytoplasmic translocation of Olig2. Additionally, the expression levels of bone morphogenetic proteins 2 and 4 (BMP2 and BMP4) and inhibitor of DNA binding 2 and 4 (Id2 and Id4) were greatly elevated during astroglial differentiation. BMP inhibition by noggin suppressed the astroglial differentiation of OPCs. Our results indicate that Olig2 may serve as a key regulator during the directional differentiation of progenitor cells after demyelination. The BMP signaling pathway may contribute to the cytoplasmic translocation and altered expression of Olig2 during the remyelination process. These findings provide a better understanding of the mechanisms involved in remyelination., (Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.)

Polysialic acid (PSA) is a carbohydrate polymer added post-translationally on the neural cell adhesion molecule (NCAM) affecting its adhesion properties. It has been suggested that the presence of PSA in demyelinated lesions in multiple sclerosis could prevent axon-glia interactions inhibiting spontaneous remyelination. The enzyme St8siaIV is one of the two polysialyltransferases responsible for PSA synthesis, and it is predominantly active during adult life. Here we treated 8-10-weeks old St8siaIV deficient and wild-type mice for 5 weeks with cuprizone, which is a reliable model for de- and remyelination in the corpus callosum and cortex. Developmental myelination of the St8siaIV knock-out mice was not disturbed and adult mice showed normal myelin protein expression. Demyelination did not differ between transgenic and wild-type mice but early myelin protein re-expression and thus remyelination were accelerated in St8siaIV knock-out mice during the first week after withdrawal of the toxin. This was mainly due to enhanced oligodendrocyte precursor cells (OPC) differentiation and to a lesser extent to OPC recruitment. These data are proof of principle that PSA expression interferes at least to some extent with remyelination in vivo., (Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.)

Cuprizone is used to obtain demyelination in mice. Cuprizone-treated mice show symptoms similar to several neurodegenerative disorders such as severe status spongiosus. Although it has a simple chemical formula, its neurotoxic mechanism is still unknown. In this work, we examined both physico-chemical properties and biological effects of cuprizone. Our results indicate that cuprizone has very complicated and misunderstood solution chemistry. Moreover, we show here the inability of cuprizone to cross neither the intestinal epithelial barrier nor the neuronal cell membrane, as well its high tolerability by cultured neurons. If added to mice diet, cuprizone does not accumulate in liver or in brain. Therefore, its neurotoxic effect is explainable only in terms of its capability to chelate copper, leading to chronic copper deficiency., (Copyright © 2010 Elsevier Inc. All rights reserved.)