Icariin ameliorates the cuprizone-induced demyelination associated with antioxidation and anti-inflammation.

The treatment of immunomodulation in multiple sclerosis (MS) can alleviate the severity and relapses. However, it cannot improve the neurological disability of patients due to a lack of myelin protection and regeneration. Therefore, remyelinating therapies may be one of the feasible strategies that can prevent axonal degeneration and restore neurological disability. Natural product icariin (ICA) is a flavonol compound extracted from epimedium flavonoids, which has neuroprotective effects in several models of neurological diseases. Here, we attempt to explore whether ICA has the potential to treat demyelination and its possible mechanisms of action using lipopolysaccharide-treated BV2 microglia, primary microglia, bone marrow-derived macrophages, and cuprizone-induced demyelination model. The indicators of oxidative stress and inflammatory response were evaluated using commercial kits. The results showed that ICA significantly reduced the levels of oxidative intermediates nitric oxide, hydrogen peroxide, malondialdehyde, and inflammatory cytokines TNF-α, IL-1ß, and increased the levels of antioxidants superoxide dismutase, catalase, glutathione peroxidase, and anti-inflammatory cytokines IL-10 and TGF-ß in vitro cell experiments. In vivo demyelination model, ICA significantly alleviated the behavioral abnormalities and enhanced the integrated optical density/mm2 of Black Gold II and myelin basic protein myelin staining, accompanied by the inhibition of oxidative stress/inflammatory response. Immunohistochemical staining showed that ICA significantly induced the expression of nuclear factor erythroid derived 2/heme oxygenase-1 (Nrf2/HO-1) and inhibited the expression of toll-like receptor 4/ nuclear factor kappa B (TLR4/NF-κB), which are two key signaling pathways in antioxidant and anti-inflammatory processes. Our results strongly suggest that ICA may be used as a potential agent to treat demyelination via regulating Nrf2/HO-1-mediated antioxidative stress and TLR4/NF-κB-mediated inflammatory responses.

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.

[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.

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.

Mdivi-1, a mitochondrial fission inhibitor, modulates T helper cells and suppresses the development of experimental autoimmune encephalomyelitis.

BACKGROUND: Unrestrained activation of Th1 and Th17 cells is associated with the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). While inactivation of dynamin-related protein 1 (Drp1), a GTPase that regulates mitochondrial fission, can reduce EAE severity by protecting myelin from demyelination, its effect on immune responses in EAE has not yet been studied. METHODS: We investigated the effect of Mdivi-1, a small molecule inhibitor of Drp1, on EAE. Clinical scores, inflammation, demyelination and Drp1 activation in the central nervous system (CNS), and T cell responses in both CNS and periphery were determined. RESULTS: Mdivi-1 effectively suppressed EAE severity by reducing demyelination and cellular infiltration in the CNS. Mdivi-1 treatment decreased the phosphorylation of Drp1 (ser616) on CD4+ T cells, reduced the numbers of Th1 and Th17 cells, and increased Foxp3+ regulatory T cells in the CNS. Moreover, Mdivi-1 treatment effectively inhibited IFN-γ+, IL-17+, and GM-CSF+ CD4+ T cells, while it induced CD4+ Foxp3+ regulatory T cells in splenocytes by flow cytometry. CONCLUSIONS: Together, our results demonstrate that Mdivi-1 has therapeutic potential in EAE by modulating the balance between Th1/Th17 and regulatory T cells.

Sialic acid accelerates the electrophoretic velocity of injured dorsal root ganglion neurons.

Peripheral nerve injury has been shown to result in ectopic spontaneous discharges on soma and injured sites of sensory neurons, thereby inducing neuropathic pain. With the increase of membrane proteins on soma and injured site neurons, the negatively charged sialic acids bind to the external domains of membrane proteins, resulting in an increase of this charge. We therefore speculate that the electrophoretic velocity of injured neurons may be faster than non-injured neurons. The present study established rat models of neuropathic pain via chronic constriction injury. Results of the cell electrophoresis test revealed that the electrophoretic velocity of injured neuronal cells was faster than that of non-injured (control) cells. We then treated cells with divalent cations of Ca(2+) and organic compounds with positive charges, polylysine to counteract the negatively charged sialic acids, or neuraminidase to specifically remove sialic acids from the membrane surface of injured neurons. All three treatments significantly reduced the electrophoretic velocity of injured neuronal cells. These findings suggest that enhanced sialic acids on injured neurons may accelerate the electrophoretic velocity of injured neurons.

[Renal protection of Tangke Decoction on rats with diabetes and its effect on the expression of TGF-beta1/Smad4].

OBJECTIVE: To observe the effect of Tangke Decoction (TD) on the expression of TGF-beta1/Smad4 of rats with early diabetes and to explore the effect and mechanism of TD against the renal injury induced by diabetes. METHODS: SD rats were randomly divided into the normal control group (n = 12), the model group (n = 10), the Chinese herbs prevented group (n =10), the Chinese herbs treated group (n = 10), and the Western medicine control group (n = 10). TD (18 mg/kg) was given by gastrogavage to rats in the Chinese herbs prevented group immediately after successful modeling for 12 weeks, once daily. At the 4th week of successful modeling, rats in the rest 4 groups were administered by gastrogavage. Equal volume of normal saline was given to rats in the model group and the normal control group. Benazepril suspension (1 mg/kg) was administered by gastrogavage to rats in the Western medicine control group for 8 weeks, once daily. TD (18 mg/kg) was given by gastrogavage to rats in the Chinese herbs treated group for 8 weeks, once daily. The body weight, kidney weight, index of kidney weight, fasting blood sugar, 24 h urinary albumin excretion rate were examined after experiment. The pathological changes of the renal tissue were observed by HE staining, Masson staining, and electron microscope. The expression of renal transforming growth factor-beta1, (TGF-beta1) and Smad4 were detected using immunohistochemical assay. RESULTS: Compared with the normal control group, the body weight of rats decreased significantly; the kidney weight, index of kidney weight, blood sugar, 24 h urinary protein excretion, the urinary albumin excretion rate,TGF-beta1 and Smad4 expression increased significantly in the model group (all P < 0.01). Compared with the model group, the aforesaid indices were improved in each treatment group with statistical difference (P < 0.05, P < 0.01). Compared with the Western medicine control group, the kidney weight, index of kidney weight, blood sugar, 24 h urinary protein excretion, and the urinary albumin excretion rate were obviously improved in the Chinese herbs prevented group (P < 0.01). The renal pathological changes were most obvious in the model group significantly, but they were improved in all treatment groups. CONCLUSION: TD could obviously improve the symptoms of diabetes and down-regulate the expression of renal TGF-beta1 and Smad4 of early diabetic nephropathy rats, which suggested that TD had certain preventive effect on early diabetic nephropathy.

The inhibition of Rho kinase blocks cell migration and accumulation possibly by challenging inflammatory cytokines and chemokines on astrocytes.

Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are autoimmune diseases characterized by the immune-mediated demyelination and neurodegeneration of the CNS. Our previous studies showed that Rho kinase inhibitor Fasudil can delay onset, and ameliorate severity of EAE, accompanied by the improvement in myelination and the inhibition of inflammatory responses in the CNS. In this study, we found that Fasudil inhibited the migration of T cells indirectly by affecting the production of inflammatory factors and the expression of chemokines in astrocytes functions, indicating that Fasudil treatment reduced inflammatory cytokines such as TNF-α and IL-6, reactive oxygen species (NO) and chemokines like MIP-3α (CCL-20), RANTES (CCL5), MIP-1α (CCL-3) and MCP-1 (CCL2) in vitro, and blocked the chemotaxis of reactive mononuclear cells in EAE mice. Further studies found that Fasudil treatment reduced the infiltration and accumulation of pathogenic T cells into the CNS. Astrocytes expressing GFAP and CCL-20 were inhibited in Fasudil-treated EAE compared with control mice. These results demonstrate that Fasudil alleviates the pathogenesis of EAE possibly by blocking astrocyte-derived chemokine-mediated migration of inflammatory macrophages and pathogenic T cells, and might be used to treat MS.

[Effect of Fasudil on the phenotype conversion of LPS-stimulated BV-2 microglia].

AIM: To explore the effect of Fasudil on LPS-stimulated BV-2 microglia in inflammatory reaction and phenotype conversion. METHODS: The routinely cultured BV-2 microglia in vitro were divided into PBS control group, PBS plus Fasudil treatment group, LPS stimulation group and LPS plus Fasudil group. We determined the production of NO by Griess reaction, the level of TNF-α by ELISA, and analyzed the M1 and M2 phenotypes of microglia by flow cytometry. RESULTS: The treatment of LPS lead to the characteristics of M1 phenotype in BV-2 microglia. Fasudil inhibited the production of NO and the release of TNF-α in LPS-stimulated BV-2 microglia. Interestingly, Fasudil transformed inflammatory M1 cells to anti-inflammatory M2 cells. CONCLUSION: Fasudil shows an anti-inflammatory effect, which may be associated with the conversion of inflammatory M1 microglia to anti-inflammatory M2 cells.

Mechanisms related to neuron injury and death in cerebral hypoxic ischaemia.

Cerebral hypoxic-ischaemic injury is involved in many central nervous system diseases. The mechanisms of neuron injury and death in cerebral hypoxic ischaemia remain unclear. There have been many theories on pathogenesis of neuron injury and death in cerebral hypoxic ischaemia, such as the toxicity of excitatory amino acid, NO, the production of oxygen free radicals, chondriosome injury, complement component, injury of immunological inflammation, matrix metalloproteinase, dopamine, Ca2+ overloading, cell apoptosis and so on. The aim of this review is to describe recent observations regarding the mechanisms of neuron injury and death in cerebral hypoxic ischaemia.

[Suppression of murine EAE by triptolide is related to downregulation of INF-gamma and upregulation of IL-10 secretion in splenic lymphocytes].

AIM: To explore the therapeutic effectivity and the possible mechanism of triptolide (Tri) on experimental autoimmune encephalomyelitis (EAE). METHODS: All female C57BL/6 mice were randomly divided into EAE group (28), Tri treated group (20) and adjuvant group (18). Mice in EAE and treated groups were immunized with myelin oligodendrocyte glycoprotein peptides 35-55 (MOG(35-55);), adjuvant group was injected at the same time, but instead of MOG(35-55); with normal saline. Tri was intraperitoneally injected in the dosage of 100 microg/(kg.d) in treated group on day 5 post-immunization (p.i.), and mice in EAE and adjuvant group injected with normal saline as control. The clinical feature and pathological changes were observed and the splenic lymphocytes were prepared on days 18-20 p.i. The cell cultures were divided into the control group (only 200 microL of cell suspension) and the experimental group (cell suspension in the presence of 10 mg/L MOG(35-55);). Then all of them were inoculated in 96-well flat-bottom plates under 37 degrees Celsius, 50 mL/L CO(2);. After 48 h, the proliferation assay was determined by MTT, and the supernatants were harvested for the detection of INF-gamma, IL-17, IL-10 and IL-4 by ELISA. RESULTS: Tri treatment showed an significantly protective action on EAE. After the intervention of Tri, the levels of IL-10 were increased (P<0.05), but the secretion of INF-gamma and proliferation response of splenic lymphocytes induced by MOG(35-55); were statistically significantly inhibited(P<0.05 and P<0.01, respectively). There were no influences on the amount of IL-17 and IL-4 by Tri. CONCLUSION: Tri is an effective drug in suppressing murine EAE. This suppression is supposed to be related to downregulation of INF-gamma and upregulation of IL-10 secretion in splenic lymphocytes.

Immunologic pathogenesis of multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disease. The etiology and pathogenesis of MS remain unclear. At present, there are substantial evidences to support the hypothesis that genetics plays a crucial role. The people who have genetic predisposing genes easily develop immune-mediated disorder, probably in conjunction with environmental factors. The aim of this review is to describe recent observations regarding the immunologic pathogenesis of MS.