Cuprizone-induced Demyelination Mouse Model Research Articles

High-intensity interval training stimulates remyelination via the Wnt/β-catenin pathway in cuprizone-induced demyelination mouse model

ABSTRACT Objectives This study aims to investigate the role of high-intensity interval training (HIIT) in promoting myelin sheath recovery during the remyelination phase in cuprizone (CPZ)-induced demyelination mice and elucidate the mechanisms involving the Wnt/β-catenin pathway. Methods After 5 weeks of a 0.2% CPZ diet to induce demyelination, a 4-week recovery phase with a normal diet was followed by HIIT intervention. Mice body weight was monitored. Morris water maze (MWM) gauged spatial cognition and memory, while the open field test (OFT) assessed anxiety levels. Luxol fast blue (LFB) staining measured demyelination, and immunofluorescence examined myelin basic protein (MBP) and platelet-derived growth factor receptor-alpha (PDGFR-α). Western blotting analyzed protein expression, including MBP, PDGFR-α, glycogen synthase kinase-3β (GSK3β), β-catenin, and p-β-catenin. Real-time PCR detected mRNA expression levels of CGT and CST. Results HIIT promoted remyelination in demyelinating mice, enhancing spatial cognition, memory, and reducing anxiety. LFB staining indicated decreased demyelination in HIIT-treated mice. Immunofluorescence demonstrated increased MBP fluorescence intensity and PDGFR-α+ cell numbers with HIIT. Western blotting revealed HIIT reduced β-catenin levels while increasing p-β-catenin and GSK3β levels. Real-time PCR demonstrated that HIIT promoted the generation of new myelin sheaths. Additionally, the Wnt/β-catenin pathway agonist, SKL2001, decreased MBP expression but increased PDGFR-α expression. Discussion HIIT promotes remyelination by inhibiting the Wnt/β-catenin pathway and is a promising rehabilitation training for demyelinating diseases. It provides a new theoretical basis for clinical rehabilitation and care programs.

Icaritin Promotes Myelination by Simultaneously Enhancing the Proliferation and Differentiation of Oligodendrocyte Precursor Cells.

Myelin repair, which is known as remyelination, is critical to the treatment of neurodegenerative diseases, and myelination depends on not only the differentiation of oligodendrocyte precursor cells toward oligodendrocytes but also the renewal of oligodendrocyte precursor cells under pathological conditions. However, simultaneously promoting the differentiation and proliferation of oligodendrocyte precursor cells in lesions remains an unmet challenge and might affect demyelinating diseases. Kidney-tonifying herbs of traditional Chinese medicine (TCM) are effective in improving the symptoms of degenerative patients. However, herbs or compounds with dual functions are unverified. The purpose of this study was to find a kidney-tonifying TCM that synchronously improved the differentiation and proliferation of oligodendrocyte precursor cells under pathological conditions. Compounds with dual functions were screened from highly frequently used kidney-tonifying TCM, and the effects of the obtained compound on remyelination were investigated in an in vitro oligodendrocyte precursor cell differentiation model under pathological conditions and in demyelinating mice in vivo. The compound icaritin, which is an active component of Yin-Yang-Huo (the leaves of Epimedium brevicornu Maxim), demonstrated multiple effects on the remyelination process, including enhancing oligodendrocyte precursor cell proliferation, facilitating the differentiation of neural progenitor cells toward oligodendrocyte precursor cells and further toward oligodendrocytes, and maturation of oligodendrocytes under corticosterone- or glutamate-induced pathological conditions. Importantly, icaritin effectively rescued behavioral functions and increased the formation of myelin in a cuprizone-induced demyelination mouse model. The multiple effects of icaritin make it a promising lead compound for remyelination therapy.

β-hydroxybutyrate attenuates demyelination, modulates microglial phenotype and supports blood-brain barrier integrity in a cuprizone-induced mouse model of demyelination

β-hydroxybutyrate has been reported to have neuroprotective activity. In this study, the neuroprotective effects of BHB were investigated on a demyelination model, the cuprizone model. We found that BHB reduced demyelination, which was confirmed by western blot for myelin-oligodendrocyte glycoprotein (MOG) and myelin proteolipid protein (PLP). Following BHB treatment, the number of connexin43+ (Cx43+) + GFAP+ cells and Iba-1+ + CD16/32+ cells decreased, whereas the number of Cx47+ + oligo2+ cells and Iba-1+ + Arginase-1+ cells increased significantly. Furthermore, BHB significantly repressed the expression of MMP-9/12, and increased the expression of blood-brain barrier (BBB) markers (such as PECAM-1 and ZO-1) in CPZ mice. We report that BHB promotes M2 microglia polarization and ameliorates BBB dysfunction caused by downregulation of HDAC3, NF-κB, Aim2 and NLRP3, as well as upregulation of SIRT1 in CPZ mice. Thus, these findings suggest that BHB may be a therapeutic approach for preventing demyelinating diseases.

The Effect of Aerobic Training With the Consumption of Probiotics on the Myelination of Nerve Fibers in Cuprizone-induced Demyelination Mouse Model of Multiple Sclerosis.

Extensive human and animal research shows that exercise has beneficial effects on multiple clinical outcomes for patients suffering from multiple sclerosis (MS). This research was conducted to examine the effect of aerobic exercise with probiotic consumption on the myelination of nerve fibers in a cuprizone-induced demyelination mouse model of MS. Rats exposed to cuprizone (CPZ) for 13 weeks were subjected to motor and balance tests in week 5. They (5 people in each group) were assigned to five groups of control (C), MS, MS with exercise (MS+Exe), MS with probiotic (MS+Pro), and MS with probiotic and exercise (MS+Pro+Exe) randomly. The exercise groups conducted aerobic exercises 5 days a week for 60 days. The rats received probiotics by gavage. Performance and balance tests were repeated when the eight-week protocol of exercise and probiotic consumption was finished. One day after these interventions, they were sacrificed to undergo biochemical and molecular biology assays. The results showed that Myelin basic protein (MBP) was increased in the MS+Pro+Exe, MS+Pro, and MS+Exe compared to the MS group (P<0.05).The nestin mRNA showed an increase in MS+Pro+Exe, MS+Exe, and MS+Pro groups compared to the MS group, but this increase was not significant in MS+Pro+Exe and MS+Exe groups compared to the control and MS groups (P>0.05). According to the results, lifestyle interventions can effectively alleviate demyelinating-inflammatory processes that happen in the brains of MS patients.

Combination Therapy of Mesenchymal Stem Cell Transplantation and Astrocyte Ablation Improve Remyelination in a Cuprizone-Induced Demyelination Mouse Model.

Astrocytes display an active, dual, and controversial role in multiple sclerosis (MS), a chronic inflammatory demyelination disorder. However, mesenchymal stem cells (MSCs) can affect myelination in demyelinating disorders. This study aimed to investigate the effect of single and combination therapies of astrocyte ablation and MSC transplantation on remyelination in the cuprizone (CPZ) model of MS. C57BL/6 mice were fed 0.2% CPZ diet for 12weeks. Astrocytes were ablated twice by L-a-aminoadipate (L-AAA) at the beginning of weeks 13 and 14 whereas MSCs were injected in the corpus callosum at the beginning of week 13. Motor coordination and balance were assessed through rotarod test whereas myelin content was evaluated by Luxol-fast blue (LFB) staining and transmission electron microscopy (TEM). Glial cells were assessed by immunofluorescence staining while mRNA expression was evaluated by quantitative real-time PCR. Combination treatment of ablation of astrocytes and MSC transplantation (CPZ + MSC + L-AAA) significantly decreased motor coordination deficits better than single treatments (CPZ + MSCs or CPZ + L-AAA), in comparison to CPZ mice. In addition, L-AAA and MSCs treatment significantly enhanced remyelination compared to CPZ group. Moreover, combination therapy caused a significant decrease in the number of GFAP+ and Iba-1+ cells, whereas oligodendrocytes were significantly increased in comparison to CPZ mice. Finally, MSC administration resulted in a significant upregulation of BDNF and NGF mRNA expression levels. Our data indicate that transient ablation of astrocytes along with MSCs treatment improve remyelination through enhancing oligodendrocytes and attenuating gliosis in a chronic demyelinating mouse model of MS.

The Effects of Repetitive Transcranial Magnetic Stimulation on Cognitive Impairment and the Brain Lipidome in a Cuprizone-Induced Mouse Model of Demyelination.

The protective effects of repetitive transcranial magnetic stimulation (rTMS) on myelin integrity have been extensively studied, and growing evidence suggests that rTMS is beneficial in improving cognitive functions and promoting myelin repair. However, the association between cognitive improvement due to rTMS and changes in brain lipids remains elusive. In this study, we used the Y-maze and 3-chamber tests, as well as a mass spectrometry-based lipidomic approach in a CPZ-induced demyelination model in mice to assess the protective effects of rTMS on cuprizone (CPZ)-induced cognitive impairment and evaluate changes in lipid composition in the hippocampus, prefrontal cortex, and striatum. We found that CPZ induced cognitive impairment and remarkable changes in brain lipids, specifically in glycerophospholipids. Moreover, the changes in lipids within the prefrontal cortex were more extensive, compared to those observed in the hippocampus and striatum. Notably, rTMS ameliorated CPZ-induced cognitive impairment and partially normalized CPZ-induced lipid changes. Taken together, our data suggest that rTMS may reverse cognitive behavioral changes caused by CPZ-induced demyelination by modulating the brain lipidome, providing new insights into the therapeutic mechanism of rTMS.

Changes in leptin, serotonin, and cortisol after eight weeks of aerobic exercise with probiotic intake in a cuprizone-induced demyelination mouse model of multiple sclerosis

BackgroundMultiple sclerosis (MS) is the most common non-traumatic neurological cause of disability in young adults. Physical activity, particularly exercise training, is an evidence-based approach to managing symptoms, restoring function, and improving overall wellness in people with MS. As well, the use of probiotics can be effective in reducing the damage from inflammation in MS patients. ObjectiveThe study aimed to address changes in leptin, serotonin, and cortisol following eight weeks of aerobic exercise along with probiotic intake in a cuprizone-induced demyelination mouse model of MS. MethodsMice were exposed to cuprizone for 12 weeks. After 5 weeks, beam and performance tests were performed on them. The mice (n = 5 per group) were randomly divided into five groups: control (C), MS, MS with exercise (MS + Exe), MS with probiotic (MS + Prob), and MS with probiotic and exercise (MS + Prob + Exe). Exercise groups performed aerobic exercises 5 days a week, 10 min in the first week, 20 min in the second week, and 30 min daily in the third week until the eighth week. In the probiotic groups, the mice received probiotic by gavage. They were sacrificed after 3 months. Biochemical and molecular biology analyses were performed. ResultsThe results showed that leptin gene expression values in the MS + Prob + Exe, MS + Prob, and MS + Exe groups showed a decrease compared to the MS group, but the reduction was not significant (p > 0.05). Also, the leptin Elisa test in these intervention groups showed a significant decrease (P < 0.05). The serotonin gene expression values in the MS + Prob + Exe, MS + Prob, and MS + Exe groups were increased compared to the MS group, but the increase was not significant (p > 0.05). Furthermore, the serotonin Elisa test in these intervention groups showed a significant increase (P < 0.05). The cortisol Elisa test values in the MS + Exe and MS + Prob groups exhibited a decrease compared to the MS group, but the reduction was not significant (p > 0.05). ConclusionOverall, these results suggest that lifestyle interventions can be effective in improving pathological factors in patients with MS.

18β-Glycyrrhetinic acid alleviates demyelination by modulating the microglial M1/M2 phenotype in a mouse model of cuprizone-induced demyelination

This research aimed to examine the nutritious supplementary function of 18β-Glycyrrhetinic acid (18β-GA) in moderating the myelin sheath destruction and behavioral impairments observed in the cuprizone model of demyelination. Mice were fed daily on food containing cuprizone (0.3 %) and given doses of 18β-GA (5 or 1 mg/kg) for a period of five weeks. The groups treated with 18β-GA exhibited improvements in exploratory behavior, locomotive activity, and weight. As assessed using luxol-fast blue and myelin basic protein (MBP) staining, which were used to detect demyelination in the brain, 18β-GA both reduced and prevented instances of cuprizone-induced demyelinating lesions; treatment with 18β-GA also caused the MBP level in the corpus callosum to increase. Furthermore, alongside these positive results following 18β-GA treatment, microglial polarisation was also observed to shift towards the beneficial M2 phenotype. The results of this research thus indicate the potential clinical application of 18β-GA for the prevention of myelin damage and behavioral dysfunction.

Trpv4 regulates Nlrp3 inflammasome via SIRT1/PGC-1α pathway in a cuprizone-induced mouse model of demyelination

Increasing evidence has demonstrated that the Nod-like receptor pyrin domain containing 3 (Nlrp3) inflammasome overactivated during demyelinating disorders. It has been implicated that transient receptor potential type 4 (Trpv4) is regarded as a polymodal ionotropic receptor that plays an important role in a multitude of pathological conditions, including inflammation. The aim of this study was to investigate whether the Trpv4 channel regulates Nlrp3 inflammasome in the corpus callosum of mice with demyelination. Our results showed that CPZ treatment significantly increased the expression of Trpv4, activated Nlrp3 inflammasome, reduced peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) and decreased mitochondrial function. siRNA-mediated Nlrp3 knockdown inhibited glial activation and alleviated demyelination. Whereas knockdown of Trpv4 by siRNA markedly ameliorated Nlrp3 inflammasome activation and restored mitochondrial function as well as reducing the level of reactive oxygen species (ROS). Meanwhile, glial activation, demyelination and behavioral impairment induced by CPZ were also alleviated by siRNA-mediated Trpv4 knockdown. Furthermore, immunoprecipitation and use of a lysine acetylation assay showed that Sirtuin1 (SIRT1) mediated the PGC-1α deacetylation, which is involved in Nlrp3 inflammasome activation. These findings suggest that Trpv4 regulates mitochondrial function through the SIRT1/PGC-1α pathway, which further trigger Nlrp3 inflammasome activation in the CPZ-induced demyelination in mice.

The Intellicage system provides a reproducible and standardized method to assess behavioral changes in cuprizone-induced demyelination mouse model

BackgroundMultiple sclerosis is a neurodegenerative disorder characterized by myelin loss in the brain parenchyma. To mimic the disease, mice are fed a cuprizone-supplemented diet for 5 weeks, which leads to demyelination of white and grey matter regions, with the corpus callosum being the most susceptible to cuprizone intoxication. Although this model is highly exploited, classical behavioural tests showed inconsistent results. ObjectiveIn our study, we aimed to use the automated system Intellicage to phenotype the behaviour of cuprizone-fed mice. MethodsMice were continuously monitored during the 5 weeks of intoxication in their home cages, with minimal interference from the experimenter. Mice were assessed for spontaneous activity, fine movements, and impulsivity. ResultsConsistently, cuprizone-fed mice showed reduced activity and impulsivity throughout the test period. These behavioral results were confirmed by repeating the battery of behavioral tests in a second cohort of cuprizone-fed mice. Our results suggest that the behavioural phenotyping of cuprizone-fed mice using Intellicage is reproducible and sensitive enough to detect changes normally missed in standard behavioral test batteries. ConclusionUsing a reproducible and standardized method to assess behavioral changes in mice intoxicated with cuprizone is crucial to better understand the disease as well as the functional outcome of treatments.

Effects of Lactobacillus casei Strain T2 (IBRC-M10783) on the Modulation of Th17/Treg and Evaluation of miR-155, miR-25, and IDO-1 Expression in a Cuprizone-Induced C57BL/6 Mouse Model of Demyelination.

Multiple sclerosis (MS) is a complex inflammatory disease in which demyelination occurs in the central nervous system affecting approximately 2.5 million people worldwide. Recent reports have shown that the gut microbiome plays a crucial role in the functioning of the immune system in inflammatory diseases such as MS. In this study, the cuprizone-induced demyelination mouse model was used to investigate the effect of Lactobacillus casei strain T2 (IBRC-M10783) on the alleviation of these mice. Female C57BL/6 mice (8-10weeks old) were divided into 6 groups: group 1, normal control; group 2, cuprizone control (oral administration of cuprizone 0.2% w/w for 4weeks); group 3, probiotic control (oral administration of 1 × 109CFU/ml probiotic for 4weeks); group 4, treatment 1 (probiotic for 4weeks then cuprizone for 4weeks); group 5, treatment 2 (cuprizone for 4weeks then probiotic for 4weeks); and group 6, treatment 3 (cuprizone for 4weeks then probiotic for 4weeks with vitamin D3 at a dose of 20IU/day). Then, TGF-β and IL-17 were measured by ELISA, and the expression of miR-155, miR-25, and IDO-1 was evaluated by real-time PCR. Among the measured microRNAs, the results showed that there was a significant decrease in miR-155 expression between the treatment 1 group and the cuprizone group. In the case of IL-17, the results also showed a significant reduction between the three treatment groups and the cuprizone group. These observations suggest that L. casei can reduce proinflammatory cytokines and reduce demyelinating symptoms in the mouse model.

Calorie restriction promotes remyelination in a Cuprizone-Induced demyelination mouse model of multiple sclerosis.

Over the past few decades several attempts have been made to introduce a potential and promising therapy for Multiple sclerosis (MS). Calorie restriction (CR) is a dietary manipulation to reduce calorie intake which has been shown to improve neuroprotection and attenuate neurodegenerative disorders. Here, we evaluated the effect of 33% CR regimen for 4 weeks on the remyelination capacity of Cuprizone (CPZ) induced demyelination in a mouse model of MS. Results showed that CR induced a significant increase in motor coordination and balance performance in CPZ mice. Also, luxol fast blue (LFB) staining showed that CR regimen significantly improved the remyelination in the corpus callosum of CPZ + CR mice compared to the CPZ group. In addition, CR regimen significantly increased the transcript expression levels of BDNF, Sox2, and Sirt1 in the corpus callosum of CPZ mice, while decreasing the p53 levels. Moreover, CR regimen significantly decreased the apoptosis rate. Furthermore, astrogliosis (GFAP + astrocytes) and microgliosis (Iba-1 + microglia) were significantly decreased by CR regimen while oligodendrogenesis (Olig2+) and Sirt1 + cell expression were significantly increased in the corpus callosum of CPZ + CR mice compared to the CPZ group. In conclusion, CR regimen can promote remyelination potential in a CPZ-demyelinating mouse model of MS by increasing oligodendrocyte generation while decreasing their apoptosis.

NEP1-40 alleviates behavioral phenotypes and promote oligodendrocyte progenitor cell differentiation in the hippocampus of cuprizone-induced demyelination mouse model

BackgroundStudies have demonstrated that the failure of oligodendrocyte precursor cells (OPCs) differentiation as a major cause of remyelination failure in demyelinating disease. The reasons for this failure are not completely understood. We hypothesized that the present of myelin debris in CNS play an important role in poor OPCs differentiation in the mouse model of demyelinating disease. MethodsMice were fed by the food mixed with normal or 0.2 % cuprizone (CPZ) for 6 weeks. Then the learning and memory impairment were tested by Morris water maze test. The spontaneous alternation behavior and depression-like symptoms were assessed by tail suspension test and open filed test. The number of OPCs and oligodendrocytes were counted by immunofluorescence. After exposed to CPZ for 6 weeks, the mice were then receiving stereotactic injection of NEP1-40 into the CA3 of hippocampus. The behavioral, learning and memory changes were assessed by tail suspension test and open field test. The differentiation of OPCs were detected by immunofluorescence and western blot. ResultsThe mice in CPZ group are more likely to show signs of depression and they showed impairment of long-term learning and memory function. The differentiation of OPCs were impaired in CPZ group. We found that mice treated with NEP1-40 showed less depression-like symptom in TST and higher locomotor activity in the OFT than the mice treated with PBS. ConclusionsOur study suggest that NEP1-40 can promote OPC differentiation and survival. Further study should focus on the effect of NEP1-40 on the differentiation and survival of OPCs in vitro.

Differential Expression of miRNAs and Behavioral Change in the Cuprizone-Induced Demyelination Mouse Model.

The demyelinating diseases of the central nervous system involve myelin abnormalities, oligodendrocyte damage, and consequent glia activation. Neurotoxicant cuprizone (CPZ) was used to establish a mouse model of demyelination. However, the effects of CPZ on microRNA (miRNA) expression and behavior have not been clearly reported. We analyzed the behavior of mice administered a diet containing 0.2% CPZ for 6 weeks, followed by 6 weeks of recovery. Rotarod analysis demonstrated that the treated group had poorer motor coordination than control animals. This effect was reversed after 6 weeks of CPZ withdrawal. Open-field tests showed that CPZ-treated mice exhibited significantly increased anxiety and decreased exploratory behavior. CPZ-induced demyelination was observed to be alleviated after 4 weeks of CPZ treatment, according to luxol fast blue (LFB) staining and myelin basic protein (MBP) expression. miRNA expression profiling showed that the expression of 240 miRNAs was significantly changed in CPZ-fed mice compared with controls. Furthermore, miR-155-5p and miR-20a-5p upregulations enhanced NgR induction through Smad 2 and Smad 4 suppression in demyelination. Taken together, our results demonstrate that CPZ-mediated demyelination induces behavioral deficits with apparent alterations in miRNA expression, suggesting that differences in miRNA expression in vivo may be new potential therapeutic targets for remyelination.

Cordycepin (3′-deoxyadenosine) promotes remyelination via suppression of neuroinflammation in a cuprizone-induced mouse model of demyelination

Multiple sclerosis (MS) is an inflammatory demyelination disease characterized by autoimmune damage to the central nervous system. In this disease, failure of remyelination could cause persistent disability. Cordycepin, also known as 3′-deoxyadenosine, exerts anti-inflammatory, anti-oxidic, anti-apoptotic and neuroprotective effects. The cuprizone (CPZ) model has been widely used to study MS as it mimics some characteristics of demyelination disease. To determine whether cordycepin promotes remyelination and functional recovery after CPZ-induced demyelination, we administered cordycepin to the CPZ-induced demyelination mice. Cordycepin reversed CPZ-induced loss of body weight and rescued motor dysfunction in the model mice. Cordycepin effectively promoted remyelination and enhanced MBP expression in the corpus callosum. Cordycepin also inhibited the CPZ-induced increase in the number of Iba1-positive microglia, GFAP-positive astrocytes and Olig2-positive oligodendroglial precursor cells in the corpus callosum and cerebral cortex. Pro-inflammatory cytokine expression (IL-1β and IL-6) was inhibited while anti-inflammatory cytokine IL-4 and neurotrophic factor BDNF release was elevated in the corpus callosum and hippocampus after cordycepin treatment. In addition, we also found that cordycepin ameliorated CPZ-induced body weight loss, motor dysfunction, demyelination, glial cells activation and pro-inflammatory cytokine expression in the corpus callosum and hippocampus. Our results suggest that cordycepin may represent a useful therapeutic agent in demyelination-related diseases via suppression of neuroinflammation.

Effect of the CSF1R inhibitor PLX3397 on remyelination of corpus callosum in a cuprizone-induced demyelination mouse model.

Multiple sclerosis (MS) is a chronic inflammatory disease affecting the central nervous system (CNS). Despite introducing multiple immunomodulatory approaches for MS, there are still major concerns about possible ways for improving remyelination in this disease. Microglia exert essential roles in regulation of myelination processes, and interaction between colony-stimulating factor 1 (CSF1) with its receptor CSF1R is considered as a key regulator of microglial differentiation and survival. The aim of this study was to investigate possible roles for a CSF1R inhibitor PLX3397 in recovery of central myelination processes. Chronic demyelination was induced in mice by addition of 0.2% cuprizone to the chow for 12 weeks. Next, animals were undergoing a diet containing 290 mg/kg PLX3397 to induce microglial ablation. The PLX3397 treatment caused a significant decrease in the rate of expression for the CSF1/CSF1R axis, and a reduction in the protein expressions for the microglial marker Iba-1 and for the oligodendrocyte marker Olig-2. Findings from Luxol fast blue (LFB) staining and transmission electron microscopy (TEM) showed an increase in the rate of myelination for the mice receiving PLX3397. The rate of destruction in the nerve fibers and the extent of the gaps formed between layers of myelin sheaths was also reduced after the treatment with PLX3397. In addition, animals experienced an improvement in recovery of motor deficit after receiving PLX3397 (for all P < 0.05). It could be concluded that PLX3397 could retain myelination in the MS model possibly through regulation of the myelin environment.

Repurposing of omeprazole for oligodendrocyte differentiation and remyelination

The efficiency of remyelination determines the degree of neuronal recovery and clinical amelioration of patients with Multiple Sclerosis (MS). However, the lack of drugs facilitating myelin regeneration represents a currently unmet medical need. Herein we utilized public microarray results from the GEO database and analyzed them using Connectivity-Map, which is a database connecting diseases, genes and drugs. Through this screening, we identified Omeprazole as a potential, applicable pro-remyelinating drug candidate. Incubation of isolated primary oligodendrocyte precursor cells with omeprazole in vitro significantly promoted the differentiation and maturation of oligodendrocyte precursor cells. Employing different inhibitors of the MAPK pathway, we found that the phosphorylation of ERK1/2 and p38 MAPK is required for this effect of omeprazole. The cuprizone-induced demyelination mouse model was applied to examine the pro-remyelinating effect of omeprazole in vivo. Omeprazole treatment (10 mg/kg) for 2 weeks significantly improved the impaired motor coordinative function of demyelinated mice, increased the expression of myelin basic protein (MBP) and up-regulated the expression of genes related to remyelination. The proportion of myelinated axons was also increased after omeprazole treatment as revealed by transmission electron microscopy. Our data demonstrate that omeprazole is a promising drug candidate for remyelination in MS.

Low Field Magnetic Stimulation Ameliorates Schizophrenia-Like Behavior and Up-Regulates Neuregulin-1 Expression in a Mouse Model of Cuprizone-Induced Demyelination.

White matter and myelin sheath integrity are disrupted in schizophrenia, and non-invasive magnetic brain stimulation targeting these tracts is a promising new therapeutic approach. In particular, deep-brain reachable low field magnetic stimulation (DMS) could alleviate cognitive impairment and depressive-like behaviors in animal models. In this study, we sought to assess the effects of DMS on myelin sheath damage and schizophrenia-like behaviors in the cuprizone-induced demyelination mouse model. Mice were fed cuprizone (copper ion chelating agent, 0.2% w/w mixed with food) for 6 weeks to induce demyelination. During these 6 weeks, mice were stimulated with either sham, low-frequency (LFS, delta frequency) DMS or high-frequency (HFS, gamma Hz) DMS for 20 min each day. Behavioral tests were conducted 24 h after the final DMS session. The myelin sheath was examined by immunohistochemistry and the expression of neuregulin-1 (NRG1)/ErbB4 in the prefrontal cortex was measured with Western blotting. Six weeks of HFS significantly alleviated schizophrenia-like behaviors in cuprizone mice, including improved nesting, social interaction and sensorimotor gating, while LFS improved sensorimotor gating only. HFS and LFS both repaired the myelin sheath and increased the expression of neuregulin-1 and its receptor ErbB4, in the prefrontal cortex of demyelinated mice. Our findings show that DMS is a potential effective neuromodulation technique for the treatment of schizophrenia. One possible mechanism underlying these therapeutic effects could involve the up-regulation of NRG1/ErbB4 signaling in the prefrontal cortex.

TRPV4 Inhibition Improved Myelination and Reduced Glia Reactivity and Inflammation in a Cuprizone-Induced Mouse Model of Demyelination.

The inhibition of demyelination and the promotion of remyelination are both considerable challenges in the therapeutic process for many central nervous system (CNS) diseases. Increasing evidence has demonstrated that neuroglial activation and neuroinflammation are responsible for myelin sheath damage during demyelinating disorders. It has been revealed that the nonselective cation channel transient receptor potential vanilloid 4 (TRPV4) profoundly affects a variety of physiological processes, including inflammation. However, its roles and mechanisms in demyelination have remained unclear. Here, for the first time, we found that there was a significant increase in TRPV4 in the corpus callosum in a demyelinated mouse model induced by cuprizone (CPZ). RN-1734, a TRPV4-antagonist, clearly alleviated demyelination and inhibited glial activation and the production of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) without altering the number of olig2-positive cells. In vitro, RN-1734 treatment clearly inhibited the influx of calcium and decreased the levels of IL-1β and TNF-α in lipopolysaccharide (LPS)-activated microglial cells by suppressing NF-κB P65 phosphorylation. Apoptosis of oligodendrocyte induced by LPS-activated microglia was also alleviated by RN-1734. The results suggest that activation of TRPV4 in microglia is involved in oligodendrocyte apoptosis through the activation of the NF-κB signaling pathway, thus revealing a new mechanism of CNS demyelination.

Estrogen and Progesterone Synthesis with Cellular Response in a C57BL/6 Mouse Model of Cuprizone-Induced Demyelination

Background: Demyelination refers to the degradation or loss of myelin sheath. In demyelination model studies, it has been reported that demyelination is regressed by giving steroid hormones such as estrogen and progesterone. However, there are not many studies investigating the synthesis of these two hormones by the brain during demyelination and remyelination. Neurosteroids are steroid hormones synthesized by the brain independently from peripheral tissues. In this study, it was aimed to have knowledge about the synthesis of these two hormones by the brain in experimentally formed demyelination process in brains of C57BL/6 mice and their role in the cellular response formed in the region.Materials, Methods &amp; Results: In the study, 36 C57BL/6 mice were used: 12 mice were fed normal diet for 12 weeks as control group (Group I); 12 of them were fed 0.2% cuprizone diet for 12 weeks (Group II) and 12 mice were fed normal diet for 4 weeks after feeding cuprizone diet for 8 weeks (Group III). At the end of the experiment, mice were perfused with 4% paraformaldehyde and brain tissues were blocked in paraffin. 6 μm-thick section was taken from each block. Sections were stained histologically with LFB staining and immunohistochemically with MBP staining in order to determine the demyelination in sections. All sections were also immunohistochemically stained with GFAP to detect astrocytes, with NG2 to detect young OPCs, with aromatase for estrogen synthesis and with 3βHSD antibodies for progesterone synthesis. At the end of the study, complete myelination was observed in group I, while severe demyelination was determined in group II as a result of blind evaluation of LFB and MBP staining by two pathologists. In group III, demyelination was found to be mild. In immunostaining with GFAP and NG2 antibodies, the number of GFAP and NG2 positive cells in Group II was found to be increased compared to the control group. The difference between these two groups was statistically significant (P &lt; 0.01). In group III, the number of GFAP and NG2 positive cells were found to be increased compared to the control group; however, it was found to be lower than that in experimental group II (P &lt; 0.01). In immunohistochemical staining with aromatase and 3βHSD antibody, there was no staining observed in the control groups. While an intense staining was observed in experimental group II, fewer glial staining was noticed in experimental group III when compared to the experimental group II. The difference between these two groups was found to be statistically significant (P ˂ 0.01).Discussion: Aromatase is an enzyme that converts testosterone into estrogen. On the other hand, 3βHSD is an enzyme that converts pregnenolone to progesterone. Expression of aromatase from tissues refers to the synthesis of estrogen and expression of 3βHSD refers to progesterone synthesis. In previous demyelination studies carried out with cuprizone, it has been reported that demyelination is regressed by giving estrogen and progesterone during demyelination. In the presented study, we observed that enzyme levels that catalyze the synthesis of estrogen and progesterone increased during demyelination. In the study, it was determined that estrogen and progesterone levels were increased in the region by enzymes released from the glial cells of the brain as a response to damage formed during demyelination. Interestingly, during the period in which cuprizone was excluded from the diet, it was observed that remyelination began to be formed again and that enzyme levels synthesizing these hormones started to decrease. These results suggested that estrogen and progesterone may be synthesized in the brain after a damage and may contribute to remyelination by initiating a number of cell to cell signaling steps.