Fasudil alleviates cerebral ischemia­reperfusion injury by inhibiting inflammation and improving neurotrophic factor expression in rats.

The Rho kinase inhibitor fasudil exerts neuroprotective effects. We previously showed that fasudil can regulate M1/M2 microglia polarization and inhibit neuroinflammation. Here, the therapeutic effect of fasudil on cerebral ischemia­reperfusion (I/R) injury was investigated using the middle cerebral artery occlusion and reperfusion (MCAO/R) model in Sprague­Dawley rats. The effect of fasudil on the phenotype of microglia and neurotrophic factors in the I/R brain and its potential molecular mechanism was also explored. It was found that fasudil ameliorated neurological deficits, neuronal apoptosis, and inflammatory response in rats with cerebral I/R injury. Fasudil also promoted the polarization of microglia into the M2 phenotype, in turn promoting the secretion of neurotrophic factors. Furthermore, fasudil significantly inhibited the expression of TLR4 and NF­κB. These findings suggest that fasudil could inhibit the neuroinflammatory response and reduce brain injury after I/R injury by regulating the shift of microglia from an inflammatory M1 phenotype to an anti­inflammatory M2 phenotype, which may be related to the regulation of the TLR4/ NF­κB signal pathway.

Grape Seed Extract Attenuates Demyelination in Experimental Autoimmune Encephalomyelitis Mice by Inhibiting Inflammatory Response of Immune Cells.

OBJECTIVE: To examine the anti-inflammatory effect of grape seed extract (GSE) in animal and cellular models and explore its mechanism of action. METHODS: This study determined the inhibitory effect of GSE on macrophage inflammation and Th1 and Th17 polarization in vitro. Based on the in vitro results, the effects and mechanisms of GSE on multiple sclerosis (MS)-experimental autoimmune encephalomyelitis (EAE) mice model were further explored. The C57BL/6 mice were intragastrically administered with 50 mg/kg of GSE once a day from the 3rd day to the 27th day after immunization. The activation of microglia, the polarization of Th1 and Th17 and the inflammatory factors such as tumor necrosis factor- α (TNF- α), interleukin-1 ß (IL-1 ß), IL-6, IL-12, IL-17 and interferon-γ (IFN-γ) secreted by them were detected in vitro and in vivo by flow cytometry, enzyme linked immunosorbent assay (ELISA), immunofluorescence staining and Western blot, respectively. RESULTS: GSE reduced the secretion of TNF-α, IL-1 ß and IL-6 in bone marrow-derived macrophages stimulated by lipopolysaccharide (P<0.01), inhibited the secretion of TNF-α, IL-1 ß, IL-6, IL-12, IL-17 and IFN-γ in spleen cells of EAE mice immunized for 9 days (P<0.05 or P<0.01), and reduced the differentiation of Th1 and Th17 mediated by CD3 and CD28 factors (P<0.01). GSE significantly improved the clinical symptoms of EAE mice, and inhibited spinal cord demyelination and inflammatory cell infiltration. Peripherally, GSE downregulated the expression of toll-like-receptor 4 (TLR4) and Rho-associated kinase (ROCKII, P<0.05 or P<0.01), and inhibited the secretion of inflammatory factors (P<0.01 or P<0.05). In the central nervous system, GSE inhibited the infiltration of CD45+CD11b+ and CD45+CD4+ cells, and weakened the differentiation of Th1 and Th17 (P<0.05). Moreover, it reduced the secretion of inflammatory factors (P<0.01), and prevented the activation of microglia (P<0.05). CONCLUSION: GSE had a beneficial effect on the pathogenesis and progression of EAE by inhibiting inflammatory response as a potential drug and strategy for the treatment of MS.

Neuroprotective effect of hyperoside in MPP+/MPTP -induced dopaminergic neurodegeneration.

Parkinson's disease (PD) is a neurodegenerative disease characterized by the pathological loss of nigrostriatal dopaminergic neurons, which causes an insufficient release of dopamine (DA) and then induces motor and nonmotor symptoms. Hyperoside (HYP) is a lignan component with anti-inflammatory, antioxidant, and neuroprotective effects. In this study, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active neurotoxic metabolite 1-methyl-4-phenylpyridinium ion (MPP+) were used to induce dopaminergic neurodegeneration. The results showed that HYP (100 µg/mL) reduced MPTP-mediated cytotoxicity of SH-SY5Y cells in vitro, and HYP [25 mg/(kg d)] alleviated MPTP-induced motor symptoms in vivo. HYP treatment reduced the contents of nitric oxide (NO), H2O2, and malondialdehyde (MDA), as well as the mitochondrial damage of dopaminergic neurons, both in vitro and in vivo. Meanwhile, HYP treatment elevated the levels of neurotrophic factors such as glial cell line-derived neurotrophic factor, brain-derived neurotrophic factor, and recombinant cerebral dopamine neurotrophic factor in vivo, but not in vitro. Finally, Akt signaling was activated after the administration of HYP in MPP+/MPTP-induced dopaminergic neurodegeneration. However, the blockage of the Akt pathway with Akt inhibitor did not abolish the neuroprotective effect of HYP on DA neurons. These results showed that HYP protected the dopaminergic neurons from the MPP+- and MPTP-induced injuries, which did not rely on the Akt pathway.

The effects and potential of microglial polarization and crosstalk with other cells of the central nervous system in the treatment of Alzheimer's disease.

Microglia are resident immune cells in the central nervous system. During the pathogenesis of Alzheimer's disease, stimulatory factors continuously act on the microglia causing abnormal activation and unbalanced phenotypic changes; these events have become a significant and promising area of research. In this review, we summarize the effects of microglial polarization and crosstalk with other cells in the central nervous system in the treatment of Alzheimer's disease. Our literature search found that phenotypic changes occur continuously in Alzheimer's disease and that microglia exhibit extensive crosstalk with astrocytes, oligodendrocytes, neurons, and penetrated peripheral innate immune cells via specific signaling pathways and cytokines. Collectively, unlike previous efforts to modulate microglial phenotypes at a single level, targeting the phenotypes of microglia and the crosstalk with other cells in the central nervous system may be more effective in reducing inflammation in the central nervous system in Alzheimer's disease. This would establish a theoretical basis for reducing neuronal death from central nervous system inflammation and provide an appropriate environment to promote neuronal regeneration in the treatment of Alzheimer's disease.

[Acupuncture ameliorates neurological function by suppressing microglia polarization and inflammatory response after cerebral ischemia in rats].

OBJECTIVE: To observe the effect of acupuncture on microglia polarization and inflammatory reaction in rats with cerebral ischemia-reperfusion injury (CIRI), so as to explore its mechanisms underlying improvement of CIRI. METHODS: Thirty male SD rats were randomly divided into sham operation, model, and acupuncture groups, with 10 rats in each group. The CIRI model was established by occlusion of the middle cerebral artery (MCAO) for 1 h, followed by reperfusion. After modeling, rats in the acupuncture group received manual acupuncture stimulation of "Dazhui" (GV14), "Baihui"(GV20), "Shuigou" (GV26), bilateral "Zusanli" (ST36) and "Fengchi" (GB20) by twirling the needles rapidly for 10 s/acupoint every 10 min, with the needles retained for 20 min. The treatment was conducted once daily for successive 7 days. The neurological function was evaluated according to Longa's method. The state of CIRI was observed after Nissl staining, and the expression levels of Iba-1, iNOS, Arg1, BDNF, GDNF and NeuN in the ischemic cortex tissue were detected by immunofluorescence staining. The contents of TNF-α, IL-6 and IL-10 in the ischemic tissue were assayed by ELISA. The protein expression levels of BDNF, GDNF, TLR4, MyD88 and NF-κB in the ischemic tissues were detected by Western blot. RESULTS: The neurological deficit score on the 24 h and 7th day was considerably higher in the model group than in the sham operation group (P<0.01), and evidently lower on the 7th day in the acupuncture group than in the model group (P<0.01). The number of NeuN positive cells，the area of immunofluorescence dual labelling of Arg1, BDNF and GDNF positive staining, IL-10 content, BDNF and GDNF protein expressions were significantly decreased (P<0.01), and the immunofluorescence dual labelling area of Iba-1 and iNOS, TNF-α and IL-6 contents, the pretein expression levels of TLR4, MyD88 and NF-κB considerably increased (P<0.01) in the model group relevant to the sham operation group. In contrast to the model group, the acupuncture group had a significant increase in the number of NeuN positive cells, the immunofluorescence dual labelling area of Arg1, BDNF and GDNF positive staining, IL-10 content, and BDNF and GDNF protein expressions (P<0.05, P<0.01), and an evident decrease in Iba-1 and iNOS positive staining, contents of TNF-α and IL-6, and the protein expression levels of TLR4, MyD88 and NF-κB (P<0.01, P<0.05). Nissl staining showed a marked reduction in the number of neurons, the nucleus pyknosis and nissl bodies and loose arrangement of the neuronal cells in the model group, which was relatively milder in the acupuncture group. CONCLUSION: Acupuncture intervention can improve neurological function in CIRI rats, which may be related to its effects in regulating the polarization of microglia, reducing inflammatory reaction and increasing the secretion of neurotrophic factors in the brain, inhibiting TLR4/MyD88/NF-κB signaling pathway.

Targeting the differentiation of astrocytes by Bilobalide in the treatment of Parkinson's disease model.

Background: The etiology of Parkinson's disease (PD), a chronic and progressive neurodegenerative disease, is multifactorial but not fully unknown. Until now, no drug has been proven to have neuroprotective or neuroregenerative effects in patients with PD.Objectives: To observe the therapeutic potential of Bilobalide (BB), a constituent of ginkgo biloba, in MPTP-induced PD model, and explore its possible mechanisms of action.Material and Methods: Mice were randomly divided into three groups: healthy group, MPTP group and MPTP + BB group. PD-related phenotypes were induced by intraperitoneal injection of MPTP into male C57BL/6 mice, and BB (40 mg/kg/day) was intraperitoneally given for 7 consecutive days at the end of modeling. The injection of saline was set up as the control in a similar manner.Results: BB induced M2 polarization of microglia, accompanied by inhibition of neuroinflammation in the brain. Simultaneously, BB promoted the expression of BDNF in astrocytes and neurons, and expression of GDNF in neurons. Most interestingly, BB enhanced the formation of GFAP+ astrocytes expressing nestin, Brn2 and Ki67, as well as the transformation of GFAP+ astrocytes expressing tyrosine hydroxylase around subventricular zone, providing experimental evidence that BB could promote the conversion of astrocytes into TH+ dopamine neurons in vivo and in vitro.Conclusions: These results suggest the natural product BB may utilize multiple pathways to modify degenerative process of TH+ neurons, revealing an exciting opportunity for novel neuroprotective therapeutics. However, its multi-target and important mechanisms need to be further explored.

Advantages of Rho-associated kinases and their inhibitor fasudil for the treatment of neurodegenerative diseases.

Ras homolog (Rho)-associated kinases (ROCKs) belong to the serine-threonine kinase family, which plays a pivotal role in regulating the damage, survival, axon guidance, and regeneration of neurons. ROCKs are also involved in the biological effects of immune cells and glial cells, as well as the development of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Previous studies by us and others confirmed that ROCKs inhibitors attenuated the symptoms and progression of experimental models of the abovementioned neurodegenerative diseases by inhibiting neuroinflammation, regulating immune imbalance, repairing the blood-brain barrier, and promoting nerve repair and myelin regeneration. Fasudil, the first ROCKs inhibitor to be used clinically, has a good therapeutic effect on neurodegenerative diseases. Fasudil increases the activity of neural stem cells and mesenchymal stem cells, thus optimizing cell therapy. This review will systematically describe, for the first time, the effects of abnormal activation of ROCKs on T cells, B cells, microglia, astrocytes, oligodendrocytes, and pericytes in neurodegenerative diseases of the central nervous system, summarize the therapeutic potential of fasudil in several experimental models of neurodegenerative diseases, and clarify the possible cellular and molecular mechanisms of ROCKs inhibition. This review also proposes that fasudil is a novel potential treatment, especially in combination with cell-based therapy. Findings from this review add support for further investigation of ROCKs and its inhibitor fasudil for the treatment of neurodegenerative diseases.

Wuzi Yanzong pill attenuates MPTP-induced Parkinson's Disease via PI3K/Akt signaling pathway.

Wuzi Yanzong Pill (WYP) was found to play a protective role on nerve cells and neurological diseases, however the molecular mechanism is unclear. To understand the molecular mechanisms that underly the neuroprotective effect of WYP on dopaminergic neurons in Parkinson's disease (PD). PD mouse model was induced by the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Gait and hanging tests were used to assess motor behavioral function. Immunofluorescence assay was used to determine TH-positive neurons in substantia nigra (SN). Apoptosis, dopamine and neurotrophic factors as well as expression of PI3K/Akt pathway were detected by TUNEL staining, ELISA and western blotting, respectively. First, it was observed that WYP intervention improved abnormal motor function in MPTP-induced PD model, alleviated the loss of TH+ neurons in SN, and increased dopamine content in brain, revealing a potential protective effect. Second, network pharmacology was used to analyze the possible targets and pathways of WYP action in the treatment of PD. A total of 126 active components related to PD were screened in WYP, and the related core targets included ALB, GAPDH, Akt1, TP53, IL6 and TNF. Particularly, the effect of WYP on PD may be medicate through PI3K/Akt signaling pathway and apoptotic regulation. The WYP treated PD mice had higher expression of p-PI3K, p-Akt and Bcl-2 but lower expression of Bax and cleaved caspase-3 than the non-WYP treated PD mice. Secretion of brain-derived neurotrophic factor (BDNF) and cerebral dopamine neurotrophic factor (CDNF) were also increased in the treated mice. WYP may inhibit apoptosis and increase the secretion of neurotrophic factor via activating PI3K/ Akt signaling pathway, thus protecting the loss of dopamine neurons in MPTP-induced PD mice.

The neuroprotective effects and transdifferentiation of astrocytes into dopaminergic neurons of Ginkgolide K on Parkinson' disease mice.

Parkinson's disease (PD) is a chronic and progressive movement disorder caused by the selective loss of midbrain dopaminergic neurons of unknown etiology. Up to now, although there is a great development on treatments of PD, cures with neuroprotective or nerve regenerative effects are underway for PD patients. Here we reported neuroprotective effects of Ginkgolide K (GK) when mice were upon acute MPTP exposure, in which GK ameliorated the gait dysfunction and dopaminergic neuron loss. GK exhibits its ability in immunomodulation, including switching microglia to M2 phenotype and decreasing the microglia-mediated inflammation, inhibiting peripheral CD4+IFN-γ+ and CD4+IL-17+ T cells and α-synuclein specific autoantibodies. The expression of neurotrophic factors BDNF, GDNF and NT-3 was promoted with a treatment of GK in MPTP mice brains. Notably, GK enhanced the expression of nestin in GFAP+ astrocytes followed by the transdifferentiation of astrocyte-to-neuron independent on the Wnt signaling although GK induced the expression of Wnt signaling on astrocytes. Based on these results, our work implicates a therapeutic potential of GK for protecting TH+ neurons by multiple and intercellular pathways to modify nerve regeneration in MPTP mice. However, its exactly cellular and molecular mechanisms need to be further explored and confirmed.

Temporal and spatial evolution of various functional neurons during demyelination induced by cuprizone.

Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). Here we report the temporal and spatial evolution of various functional neurons during demyelination in a cuprizone (CPZ)-induced mouse model. CPZ did not significantly induce the damage of axons and neurons after 2 wk of feeding. However, after 4-6 wk of CPZ feeding, axons and neurons were markedly reduced in the cortex, posterior thalamic nuclear group, and hippocampus. Simultaneously, the expression of TPH+ tryptophan neurons and VGLUT1+ glutamate neurons was obviously decreased, and the expression of TH+ dopaminergic neurons was slightly decreased in the tail part of the substantia nigra striatum, whereas the number of ChAT+ cholinergic neurons was not significantly different in the brain. In the second week of feeding, CPZ caused a higher level of glutamate secretion and upregulated the expression of EAAT2 on astrocytes, which should contribute to rapid and sufficient glutamate uptake and removal. This finding reveals that astrocyte-driven glutamate reuptake protected the CNS from excitotoxicity by rapid reuptake of glutamate in 4-6 wk of CPZ feeding. At this stage, although NG2+ oligodendroglia progenitor cells (OPCs) were enhanced in the demyelination foci, the myelin sheath was still absent. In conclusion, we comprehensively observed the temporal and spatial evolution of various functional neurons. Our results will assist with understanding how demyelination affects neurons during CPZ-induced demyelination and provide novel information for neuroprotection in myelin regeneration and demyelinating diseases.NEW & NOTEWORTHY Our results further indicate temporal and spatial evolution of various functional neurons during the demyelination in a cuprizone (CPZ)-induced mouse model, which mainly occur 4-6 wk after CPZ feeding. At the same time, the axonal compartment is damaged and, consequently, neuronal death occurs, while glutamate neurons are lost obviously. The astrocyte-mediated glutamate reuptake could protect the neurons from the excitatory effects of glutamate.

Fasudil enhances the phagocytosis of myelin debris and the expression of neurotrophic factors in cuprizone-induced demyelinating mice.

Multiple sclerosis (MS) is mainly associated with the neuroinflammation and demyelination in the central nervous system (CNS), in which the failure of remyelination results in persistent neurological dysfunction. Fasudil, a typical Rho kinase inhibitor, has been exhibited beneficial effects on several models of neurodegenerative disorders. In this study, we showed that Fasudil promoted the uptake of myelin debris by microglia via cell experiments and through a cuprizone (CPZ)-induced demyelinating model. In vitro, microglia with phagocytic debris exhibited enhanced expression of brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF), and the conditioned medium promoted the maturation of oligodendrocyte precursor cells (OPCs). Meanwhile, Fasudil upregulated TREM2/DAP12 pathway, which positively regulated the phagocytosis of myelin debris by microglia. Similarly, in vivo, Fasudil intervention enhanced the clearance of myelin debris, upregulated the expression of BDNF and GDNF on microglia, and promoted the formation of Oligo2+/PDGFRα+ OPCs and the maturation of MBP + oligodendrocytes in the brain. Our results showed that Fasudil targeted the phagocytic function of microglia, effectively clearing myelin debris produced during pathological process possibly by upregulating TREM2/DAP12 pathway, accompanied by increased expression of BDNF and GDNF. However, the precise mechanism underlying the effects of Fasudil in promoting phagocytic effects and neurotrophic factors remains to be elucidated.

Fasudil reduces ß-amyloid levels and neuronal apoptosis in APP/PS1 transgenic mice via inhibition of the Nogo-A/NgR/RhoA signaling axis.

Recent studies have shown that Nogo-A and the Nogo-A receptor affect ß-amyloid metabolism and the downstream Rho GTP enzyme signaling pathway, which may affect the levels of ß-amyloid and tau. Nogo-A may play a key role in the pathogenesis of Alzheimer's disease. However, the underlying molecular mechanisms of Fasudil treatment in Alzheimer's disease are not yet clear. Our results have found that Fasudil treatment for two months substantially ameliorated behavioral deficits, diminished ß-amyloid plaque and tau protein pathology, and alleviated neuronal apoptosis in APP/PS1 transgenic mice. More importantly, two well-established markers for synaptic function, growth-associated protein 43 and synaptophysin, were upregulated after Fasudil treatment. Finally, the levels of Nogo-A, Nogo-A receptor complex NgR/p75NTR/LINGO-1 and the downstream Rho/Rho kinase signaling pathway were significantly reduced. These findings suggest that Fasudil exerts its neuroprotective function in Alzheimer's disease by inhibiting the Nogo-A/NgR1/RhoA signaling pathway.

Fasudil inhibits the activation of microglia and astrocytes of transgenic Alzheimer's disease mice via the downregulation of TLR4/Myd88/NF-κB pathway.

Emerging evidence suggests an association of Alzheimer's Disease (AD) with microglial and astrocytic dysregulation. Recent studies have proposed that activated microglia can transform astrocytes to a neurotoxic A1 phenotype, which has been shown to be involved in the promotion of neuronal damage in several neurodegenerative diseases, including AD. In the present study, we observed an obvious microglial activation and A1-specific astrocyte response in the brain tissue of APP/PS1 Tg mice. Fasudil treatment improved the cognitive deficits of APP/PS1 Tg mice, inhibited microglial activation and promoted their transformation to an anti-inflammatory phenotype, and further shifted astrocytes from an A1 to an A2 phenotype. Our experiments suggest Fasudil exerted these functions by inhibing the expression of TLR4, MyD88, and NF-κB, which are key mediators of inflammation. Using in vitro experiments, we further validated in vivo findings. Our cell experiments indicated that Fasudil induces a shift of inflammatory microglia towards an anti-inflammatory phenotype. LPS-induced microglia-conditioned medium promotes A1 astrocytic polarization, but Fasudil treatment resulted in a direct transformation of A1 astrocytes to A2. To summarize, our results show that Fasudil inhibits the neurotoxic activation of microglia and shifts astrocytes towards a neuroprotective A2 phenotype, representing a promising candidate for AD treatment.

Retraction: Effect of Fasudil on remyelination following cuprizone-induced demyelination.

Retraction: Wang J, Sui R-X, Miao Q, et al. Effect of Fasudil on remyelination following cuprizone-induced demyelination. CNS Neuroscience & Therapeutics, 2020;26:76-89. https://doi.org/10.1111/cns.13154. The above article published online on May 23, 2019, in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, Professor Jun Chen, and John Wiley & Sons Ltd. The retraction has been agreed due to major overlap with a previously published article from the same group of authors.

The therapeutic potential of bilobalide on experimental autoimmune encephalomyelitis (EAE) mice.

Inflammatory demyelination in the central nervous system (CNS) is a hallmark of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Besides MS disease-modifying therapy, targeting myelin sheath protection/regeneration is currently a hot spot in the treatment of MS. Here, we attempt to explore the therapeutic potential of Bilobalide (BB) for the myelin protection/regeneration in EAE model. The results showed that BB treatment effectively prevented worsening and demyelination of EAE, accompanied by the inhibition of neuroinflammation that should be closely related to T cell tolerance and M2 macrophages/microglia polarization. BB treatment substantially inhibited the infiltration of T cells and macrophages, thereby alleviating the enlargement of neuroinflammation and the apoptosis of oligodendrocytes in CNS. The accurate mechanism of BB action and the feasibility of clinical application in the prevention and treatment of demyelination remain to be further explored.

Effect of Fasudil on remyelination following cuprizone-induced demyelination.

BACKGROUND: Multiple sclerosis is characterized by demyelination/remyelination, neuroinflammation, and neurodegeneration. Cuprizone (CPZ)-induced toxic demyelination is an experimental animal model commonly used to study demyelination and remyelination in the central nervous system. Fasudil is one of the most thoroughly studied Rho kinase inhibitors. METHODS: Following CPZ exposure, the degree of demyelination in the brain of male C57BL/6 mice was assessed by Luxol fast blue, Black Gold II, myelin basic protein immunofluorescent staining, and Western blot. The effect of Fasudil on behavioral change was determined using elevated plus maze test and pole test. The possible mechanisms of Fasudil action were examined by immunohistochemistry, flow cytometry, ELISA, and dot blot. RESULTS: Fasudil improved behavioral abnormalities, inhibited microglia-mediated neuroinflammation, and promoted astrocyte-derived nerve growth factor and ciliary neurotrophic factor, which should contribute to protection and regeneration of oligodendrocytes. In addition, Fasudil inhibited the production of myelin oligodendrocyte glycoprotein antibody and the infiltration of peripheral CD4+ T cells and CD68+ macrophages, which appears to be related to the integrity of the blood-brain barrier. CONCLUSION: These results provide evidence for the therapeutic potential of Fasudil in CPZ-induced demyelination. However, how Fasudil acts on microglia, astrocytes, and immune cells remains to be further explored.

Temporal and Spatial Dynamics of Astroglial Reaction and Immune Response in Cuprizone-Induced Demyelination.

The cuprizone (CPZ)-induced demyelination is a relatively reproducible animal model and has been extremely useful for identifying the specific cellular and molecular signals that regulate oligodendrocyte survival and efficiency of oligodendrogenesis and remyelination. Here, we reported the temporal and spatial dynamics of astroglial reaction and immune response in CPZ-induced demyelinating model. CPZ did not induce significant microglia and astrocyte reaction after 2 weeks of feeding. After 4-6 weeks of CPZ feeding, microglia and astrocytes were markedly migrated and accumulated in myelin sheath. Simultaneously, the expression of tight junction protein ZO-1 was declined and the infiltration of CD4+IFNγ+ and CD4+IL-17+ T cells was increased in the brain, accompanied by increased production of IFN-γ and IL-17 in the extract of brain. However, the levels of IFN-γ and IL-17 were reduced, while IL-6 and TNF-α were elevated in the supernatant of splenocytes. At the 4th and 6th weeks of feeding, CPZ caused astrocyte activation and upregulated the expression of BDNF, CNTF, and IGF-II, providing a neurotrophic microenvironment in the brain. At this stage, NG2+ and PDGF-Rα+ oligodendroglia progenitor cells were enhanced in the corpus callosum, but the myelin sheath is still severely lost. Therefore, targeting microglia to improve the inflammatory microenvironment should contribute to the remyelination.

Hydroxyfasudil alleviates demyelination through the inhibition of MOG antibody and microglia activation in cuprizone mouse model.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system characterized by oligodendrocyte loss and progressive neurodegeneration. The cuprizone (CPZ)-induced demyelination is widely used to investigate the demyelination/remyelination. Here, we explored the therapeutic effects of Hydroxyfasudil (HF), an active metabolite of Fasudil, in CPZ model. HF improved behavioral abnormality and reduced myelin damage in the corpus callosum. Splenic atrophy and myelin oligodendrocyte glycoprotein (MOG) antibody were observed in CPZ model, which were partially restored and obviously inhibited by HF, therefore reducing pathogenic binding of MOG antibody to oligodendrocytes. HF inhibited the percentages of CD4+IL-17+ T cells from splenocytes and infiltration of CD4+ T cells and CD68+ macrophages in the brain. HF also declined microglia-mediated neuroinflammation, and promoted the production of astrocyte-derived brain derived neurotrophic factor (BDNF) and regeneration of NG2+ oligodendrocyte precursor cells. These results provide potent evidence for the therapeutic effects of HF in CPZ-induced demyelination.

Dynamic Balance of Microglia and Astrocytes Involved in the Remyelinating Effect of Ginkgolide B.

Multiple sclerosis (MS) is an inflammatory demyelinating disorder in the central nervous system (CNS), in which remyelination failure results in persistent neurologic impairment. Ginkgolide B (GB), a major terpene lactone and active component of Ginkgo biloba, has neuroprotective effects in several models of neurological diseases. Here, our results show, by using an in vivo cuprizone (CPZ)-induced demyelinating model, administration of GB improved behavior abnormalities, promoted myelin generation, and significantly regulated the dynamic balance of microglia and astrocytes by inhibiting the expression of TLR4, NF-κB and iNOS as well as IL-1ß and TNF-α, and up-regulating the expression of Arg-1 and neurotrophic factors. GB treatment also induced the generation of oligodendrocyte precursor cells (OPCs). In vitro cell experiments yielded the results similar to those of the in vivo model. The dynamic balance by decreasing microglia-mediated neuroinflammation and promoting astrocyte-derived neurotrophic factors should contribute to endogenous remyelination. Despite GB treatment may represent a novel strategy for promoting myelin recovery, the precise mechanism of GB targeting microglia and astrocytes remains to be further explored.