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

Pirfenidone mitigates demyelination and electrophysiological alterations in multiple sclerosis: Targeting NF-κB, sirt1, and neurotrophic genes

Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system associated with progressive neurodegeneration. Pirfenidone (Pir) is a well-known antifibrotic agent; however, Pir's function in MS is little explored. We evaluated the neuroprotective effects of Pir in MS and its possible underlying mechanisms. Forty male Swiss mice were divided equally into control, cuprizone (CPZ), Pir, and CPZ + Pir groups. Assessment of motor function was conducted using neurobehavioral tests, EMG, and nerve conduction velocity (NCV). Mice's brains were extracted to measure oxidative stress, neuroinflammatory markers, and the expression of neurotrophic genes. The corpus callosum and the sciatic nerve were subjected to histopathological and immunohistochemical studies. The CPZ group was associated with significant reductions in muscle power, frequency of contraction, sciatic NCV, SOD, IL-10, SIRT1, NGF, and neuregulin-1. Significant increases in MDA, TNF-α, INF-γ, IL-17, TGF-β, and NF-κB were also detected. Multiple areas of partially demyelinated nerve fibers in the corpus callosum, the loss of oligodendrocyte nuclei, and increased microglia and astrocytes were also observed. The sciatic nerve revealed partial demyelination with significantly reduced myelin basic protein (MBP) expression. Pir significantly restored motor function, demyelination, and neurodegenerative changes induced by CPZ. Besides the antifibrotic action of Pir, we concluded that it improves motor function in MS by alleviating the demyelinating process and neurodegeneration. Its potential anti-inflammatory, antioxidant, and antifibrotic properties could be contributing factors. These effects could be mediated by modulating the NF-κB, SIRT1, NGF, and neuregulin-1 pathways. Pir is a promising agent for treating MS.

The effects of venlafaxine on depressive-like behaviors and gut microbiome in cuprizone-treated mice

Background

Cuprizone (CPZ)-treated mice show significant demyelination, altered gut microbiome, and depressive-like behaviors. However, the effects of venlafaxine (Ven) on the gut microbiome and depressive-like behavior of CPZ-treated mice are largely unclear.

Methods

Male C57BL/6J mice were fed a chow containing 0.2% cuprizone (w/w) for 5 weeks to induce a model of demyelination. Meanwhile, the gut microbiota and depressive-like behaviors were assessed after the mice were fed with Ven (20 mg/kg/day) or equal volumes of distilled water for 2 weeks by oral gavage from the third week onward during CPZ treatment.

Results

CPZ treatment decreased the sucrose preference rate in the sucrose preference test and increased the immobility time in the tail-suspension test, and it also induced an abnormality in β-diversity and changes in microbial composition. Ven alleviated the depressive-like behavior and regulated the composition of the gut microbiota, such as the increase of Lactobacillus and Bifidobacterium in CPZ-treated mice.

Conclusion

The anti-depressant effects of Ven might be related to the regulation of gut microbiota in the CPZ-treated mice.

Multi-omic profiling of the developing human cerebral cortex at the single-cell level

The cellular complexity of the human brain is established via dynamic changes in gene expression throughout development that is mediated, in part, by the spatiotemporal activity of cis-regulatory elements (CREs). We simultaneously profiled gene expression and chromatin accessibility in 45,549 cortical nuclei across six broad developmental time points from fetus to adult. We identified cell type-specific domains in which chromatin accessibility is highly correlated with gene expression. Differentiation pseudotime trajectory analysis indicates that chromatin accessibility at CREs precedes transcription and that dynamic changes in chromatin structure play a critical role in neuronal lineage commitment. In addition, we mapped cell type-specific and temporally specific genetic loci implicated in neuropsychiatric traits, including schizophrenia and bipolar disorder. Together, our results describe the complex regulation of cell composition at critical stages in lineage determination and shed light on the impact of spatiotemporal alterations in gene expression on neuropsychiatric disease.

Huperzine-A Improved Animal Behavior in Cuprizone-Induced Mouse Model by Alleviating Demyelination and Neuroinflammation

Huperzine A (HupA) is a natural acetylcholinesterase inhibitor (AChEI) with the advantages of high efficiency, selectivity as well as reversibility and can exhibit significant therapeutic effects against certain neurodegenerative diseases. It is also beneficial in reducing the neurological impairment and neuroinflammation of experimental autoimmune encephalomyelitis (EAE), a classic model for multiple sclerosis (MS). However, whether HupA can directly regulate oligodendrocyte differentiation and maturation and promote remyelination has not been investigated previously. In this study, we have analyzed the potential protective effects of HupA on the demylination model of MS induced by cuprizone (CPZ). It was found that HupA significantly attenuated anxiety-like behavior, as well as augmented motor and cognitive functions in CPZ mice. It also decreased demyelination and axonal injury in CPZ mice. Moreover, in CPZ mice, HupA increased mRNA levels of the various anti-inflammatory cytokines (Arg1, CD206) while reducing the levels of different pro-inflammatory cytokines (iNOS, IL-1β, IL-18, CD16, and TNF-α). Mecamylamine, a nicotinic acetylcholinergic receptor antagonist, could effectively reverse the effects of HupA. Therefore, we concluded that HupA primarily exerts its therapeutic effects on multiple sclerosis through alleviating demyelination and neuroinflammation.

Activation of liver X receptors protects oligodendrocytes in CA3 of stress-induced mice

Depression is a complex disorder that is associated with various structural abnormalities. Oligodendrocyte (OL) dysfunction is associated with the pathogenesis of depression and the promotion of hippocampal oligodendrocyte maturation and myelination could be a novel therapeutic strategy for ameliorating depressive behaviors. Recent studies have shown that activation of liver X receptors (LXRs) by GW3965 improves depressive phenotypes, but the effects of GW3965 on OL function and myelination in the hippocampus of depression remain relatively unclear. To address this issue, we investigated the effects of GW3965 on mature OL in the hippocampus and on the myelin sheaths of mice subjected to chronic unpredictable stress (CUS). Behavioral tests were performed to assess depressive behaviors. Then, the number of mature OLs (CC1⁺) in each hippocampal subregion was precisely quantified with immunohistochemical and stereological methods, and the density of newborn mature OLs (BrdU⁺/Olig2⁺/CC1⁺ cells) in each hippocampal subregion was quantified with immunofluorescence. In addition, myelin basic protein (MBP) staining intensity in the cornu ammonis 3 (CA3) region was assessed by using immunofluorescence. We found that both the number of CC1⁺ OLs and the density of BrdU⁺/Olig2⁺/CC1⁺ cells were obviously decreased in each hippocampal subregion of mice subjected to CUS, and 4 weeks of GW3965 treatment reversed these effects only in the CA3 region. Furthermore, the decreased MBP expression in the CA3 region of mice subjected to CUS was ameliorated by GW3965 treatment. Collectively, these results suggested that improvement of OL maturation and enhancement of myelination may be structural mechanisms underlying the antidepressant effects of LXR agonists.

Paeonol Ameliorates Cuprizone-Induced Hippocampal Demyelination and Cognitive Deficits through Inhibition of Oxidative and Inflammatory Events

Multiple sclerosis (MS) is a chronic and inflammatory disorder of the central nervous system with autoimmune nature that is typified by varying degrees of demyelination and axonal damage. Paeonol is an active ingredient in some medicinal plants with anti-inflammatory and neuroprotective property. This study was conducted to reveal whether paeonol can alleviate hippocampal demyelination and cognitive deficits in cuprizone-induced murine model of demyelination as a model of MS. C57BL/6 mice received oral cuprizone (400 mg/kg) for 6 weeks, and paeonol was administered p.o. at two doses of 25 or 100 mg/kg, starting from the second week post-cuprizone for 5 weeks. After assessment of learning and memory in different tasks, oxidative stress and inflammation were evaluated besides immunohistochemical assessment of hippocampal myelin basic protein (MBP). Paeonol (100 mg/kg) properly ameliorated cognitive deficits in Y maze, novel object discrimination (NOD) test, and Barnes maze with no significant improvement of performance in passive avoidance task. In addition, paeonol treatment at the higher dose was also associated with partial restoration of hippocampal level of oxidative stress and inflammatory markers including MDA, ROS, GSH, SOD, catalase, NF-kB, and TNF. Besides, paeonol improved MMP as an index of mitochondrial integrity and health and reduced MPO as a factor of neutrophil infiltration. Furthermore, paeonol treatment prevented hippocampal MBP immunoreactivity, indicating its prevention of demyelination. In conclusion, the current study showed the preventive effect of paeonol against cuprizone-induced demyelination and cognitive deficits through reversing most oxidative stress- and inflammation-related parameters in addition to its improvement of mitochondrial health.

Low‑field magnetic stimulation improved cuprizone‑induced depression‑like symptoms and demyelination in female mice

Depression is a common and disabling comorbidity of multiple sclerosis (MS), with currently no clear guidelines for treatment. Low-field magnetic stimulation (LFMS), a novel non-invasive neuromodulation intervention, has been previously demonstrated to rapidly alleviate mood disorders. The aim of the present study was to investigate the effects of LFMS on depression-like behaviors and demyelination in a well-established mouse model of MS. C57BL/6 female mice were fed a 0.2% cuprizone (CPZ) diet for 3 or 6 weeks to induce acute demyelination. During this time, the mice were treated with either sham or LFMS for 20 min/day, 5 days/week. After 3 or 6 weeks of treatment, behavior was assessed with the open field task, Y-maze and the forced swim test. The prefrontal cortex and hippocampus were then collected to perform immunohistochemistry and western blot analysis to verify myelination status. The CPZ diet did not cause significant locomotor deficits; however, working memory, measured using the Y maze, depression-like behavior and adaptive learning, assayed using the forced swim test, were significantly impaired in these animals. LFMS treatment demonstrated a significant antidepressant-like effect and markedly attenuated the CPZ-induced demyelination in the prefrontal cortex after 3- and 6-weeks of treatment, as observed by changes in myelin basic protein immunostaining and western blot analysis. Therefore, the results of the present study indicated that LFMS may be a promising therapy for demyelinating diseases due to the improvement of depressive symptoms via regulation of myelination in cortical areas.

NEP1‑40 promotes myelin regeneration via upregulation of GAP‑43 and MAP‑2 expression after focal cerebral ischemia in rats

Axon regeneration after lesions to the central nervous system (CNS) is largely limited by the presence of growth inhibitory molecules expressed in myelin. Nogo‑A is a principal inhibitor of neurite outgrowth, and blocking the activity of Nogo‑A can induce axonal sprouting and functional recovery. However, there are limited data on the expression of Nogo‑A after CNS lesions, and the mechanism underlying its influences on myelin growth remains unknown. The aim of the present study was to observe the time course of Nogo‑A after cerebral ischemia/reperfusion in rats using immunohistochemistry and western blot techniques, and to test the effect of its inhibitor Nogo extracellular peptide 1‑40 (NEP1‑40) on neural plasticity proteins, growth‑associated binding protein 43 (GAP‑43) and microtubule associated protein 2 (MAP‑2), as a possible mechanism underlying myelin suppression. A classic model of middle cerebral artery occlusion (MCAO) was established in Sprague‑Dawley rats, which were divided into three groups: i) MCAO model group; ii) MCAO + saline group; and iii) MCAO + NEP1‑40 group. Rats of each group were divided into five subgroups by time points as follows: days 1, 3, 7, 14 and 28. Animals that only received sham operation were used as controls. The Nogo‑A immunoreactivity was located primarily in the cytoplasm of oligodendrocytes. The number of Nogo‑A immunoreactive cells significantly increased from day 1 to day 3 after MCAO, nearly returning to the control level at day 7, increased again at day 14 and decreased at day 28. Myelin basic protein (MBP) immunoreactivity in the ipsilateral striatum gradually decreased from day 1 to day 28 after ischemia, indicating myelin loss appeared at early time points and continuously advanced during ischemia. Then, intracerebroventricular infusion of NEP1‑40, which is a Nogo‑66 receptor antagonist peptide, was administered at days 1, 3 and 14 after MCAO. It was observed that GAP‑43 considerably increased from day 1 to day 7 and then decreased to a baseline level at day 28 compared with the control. MAP‑2 expression across days 1‑28 significantly decreased after MCAO. Administration of NEP1‑40 attenuated the reduction of MBP, and upregulated GAP‑43 and MAP‑2 expression at the corresponding time points after MCAO compared with the MCAO + saline group. The present results indicated that NEP1‑40 ameliorated myelin damage and promoted regeneration by upregulating the expression of GAP‑43 and MAP‑2 related to neuronal and axonal plasticity, which may aid with the identification of a novel molecular mechanism of restriction in CNS regeneration mediated by Nogo‑A after ischemia in rats.

Intranasal Administration of Undifferentiated Oligodendrocyte Lineage Cells as a Potential Approach to Deliver Oligodendrocyte Precursor Cells into Brain

Oligodendrocyte precursor cell (OPC) migration is a mechanism involved in remyelination; these cells migrate from niches in the adult CNS. However, age and disease reduce the pool of OPCs; as a result, the remyelination capacity of the CNS decreases over time. Several experimental studies have introduced OPCs to the brain via direct injection or intrathecal administration. In this study, we used the nose-to brain pathway to deliver oligodendrocyte lineage cells (human oligodendroglioma (HOG) cells), which behave similarly to OPCs in vitro. To this end, we administered GFP-labelled HOG cells intranasally to experimental animals, which were subsequently euthanised at 30 or 60 days. Our results show that the intranasal route is a viable route to the CNS and that HOG cells administered intranasally migrate preferentially to niches of OPCs (clusters created during embryonic development and adult life). Our study provides evidence, albeit limited, that HOG cells either form clusters or adhere to clusters of OPCs in the brains of experimental animals.

Coenzyme Q10 enhances remyelination and regulate inflammation effects of cuprizone in corpus callosum of chronic model of multiple sclerosis

Multiple Sclerosis (MS) is a chronic, progressive demyelinating disease of the central nervous system that causes the most disability in young people, besides trauma. Coenzyme Q10 (CoQ10)-also known as ubiquinone-is an endogenous lipid-soluble antioxidant in the mitochondrial oxidative respiratory chain which can reduce oxidative stress and inflammation, the processes associated with demyelination in MS. Cuprizone (CPZ) intoxication is a well-established model of inducing MS, best for studying demyelination-remyelination. In this study, we examined for the first time the role of CoQ10 in preventing demyelination and induction of remyelination in the chronic CPZ model of MS. 40 male mice were divided into four groups. 3 group chewed CPZ-containing food for 12 weeks to induce MS. After 4 weeks, one group were treated with CoQ10 (150 mg/kg/day) by daily gavage until the end of the experiment, while CPZ poisoning continued. At the end of 12 weeks, tail suspension test (TST) and open field test (OFT) was taken and animals were sacrificed to assess myelin basic protein (MBP), oligodendrocyte transcription factor-1 (Olig1), tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) by real-time polymerase chain reaction (real-time PCR) and total antioxidant capacity (TAC) and superoxide dismutase (SOD) by Elisa test. Luxol fast blue (LFB) staining was used to evaluate histological changes. CoQ10 administration promoted remyelination in histological findings. MBP and Olig-1 expression were increased significantly in CoQ10 treated group compare to the CPZ-intoxicated group. CoQ10 treatment alleviated stress oxidative status induced by CPZ and dramatically suppress inflammatory biomarkers. CPZ ingestion made no significant difference between normal control group and the CPZ-intoxicated group in TST and OFT. CoQ10 can enhance remyelination in the CPZ model and potentially might have same effects in MS patients.