[Tetramethylpyrazine regulates angiogenesis of endothelial cells in cerebral ischemic stroke injury via SIRT1/VEGFA signaling pathway].

This study aims to investigate whether tetramethylpyrazine(TMP) can stimulate angiogenesis in cerebral microvascular endothelial cells and alleviate cerebral ischemic stroke(CIS) and to explore the underlying mechanisms. In the animal study, adult Sprague-Dawley rats(n=15) were assigned into sham surgery(sham), middle cerebral artery occlusion/reperfusion(MCAO/R), and MCAO/R+TMP(intraperitoneal injection of 20 mg·kg~(-1)) groups. The neurological function was evaluated by the Z-Longa method. The cerebral infarction volume was detected by TTC staining. Enzyme-linked immunosorbent assay(ELISA) was employed to detect the expression of vascular endothelial growth factor(VEGF), angiopoietin(Ang), and platelet-derived growth factor(PDGF). Immunofluorescence staining was employed to detect Ki67 and the expression of vascular endothelial growth factor A(VEGFA) and slient information regulator 1(SIRT1). Western blot was employed to determine the expression levels of VEGFA, SIRT1, angiopoietin-2(Ang-2), and platelet-derived growth factor B(PDGFB). In the cell study, mouse brain-derived endothelial cells(Bend.3) were cultured, and the optimal concentration of TMP was determined. Then, VEGF, Ang, and PDGF were detected by ELISA after the addition of cabozantinib. Western blot was employed to measure the expression of VEGFA, Ang-2, and PDGFB. Immunofluorescence staining was used to detect CD31, CD34, and Ki67, and the proliferation, migration, and tube formation ability of Bend.3 cells were observed in vitro. Western blot and immunofluorescence staining were performed to measure the expression of SIRT1 and VEGFA after addition of the SIRT1-specific inhibitor selisistat(EX-527). The results showed that compared with the sham group, the MCAO/R group had severe neurological function damage, increased infarction volume, up-regulated expression of VEGF, VEGFA, Ang, Ang-2, PDGF, and PDGFB, and down-regulated expression of Ki67 and SIRT1(P<0.01). Compared with the MCAO/R group, the MCAO/R+TMP group presented alleviated neurological function damage, reduced infarction volume, and activated expression of VEGF, VEGFA, Ang, Ang-2, PDGF, PDGFB, Ki67, and SIRT1(P<0.01). The cell experiments showed that compared with the normal group, Bend.3 cells were activated by oxygen glucose deprivation/reoxygenation(OGD/R) treatment(P<0.05, P<0.01). Compared with the OGD/R group, the OGD/R+TMP group upregulated the expression levels of VEGF, VEGFA, Ang, Ang-2, PDGF, PDGFB, SIRT1, Ki67, CD31, and CD34, enhanced the angiogenic ability of Bend.3 cells without being inhibited by BMS or EX-527(P<0.05, P<0.01, P<0.001). The results suggest that TMP can activate the SIRT1/VEGFA signaling pathway to stimulate angiogenesis and alleviate CIS injury.

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.

Hydroxyfasudil regulates immune balance and suppresses inflammatory responses in the treatment of experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a central nervous system (CNS) disease with complicated etiology. Multifocal demyelination and invasion of inflammatory cells are its primary pathological features. Fasudil has been confirmed to improve experimental autoimmune encephalomyelitis (EAE), an animal model of MS. However, Fasudil is accompanied by several shortcomings in the clinical practice. Hydroxyfasudil is a metabolite of Fasudil in the body with better pharmaceutical properties. Therefore, we attempted to study the influence of Hydroxyfasudil upon EAE mice. The results demonstrated that Hydroxyfasudil relieved the symptoms of EAE and the associated pathological damage, reduced the adhesion molecules and chemokines, decreased the invasion of peripheral immune cells. Simultaneously, Hydroxyfasudil modified the rebalance of peripheral T cells. Moreover, Hydroxyfasudil shifted the M1 phenotype to M2 polarization, inhibited inflammatory signaling cascades as well as inflammatory factors, and promoted anti-inflammatory factors in the CNS. In the end, mice in the Hydroxyfasudil group expressed more tight junction proteins, indirectly indicating that the blood-brain barrier (BBB) was protected. Our results indicate that Hydroxyfasudil may be a prospective treatment for MS.

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.

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.

Drug-induced microglial phagocytosis in multiple sclerosis and experimental autoimmune encephalomyelitis and the underlying mechanisms.

Microglia are resident macrophages of the central nervous system (CNS). It plays a significant role in immune surveillance under physiological conditions. On stimulation by pathogens, microglia change their phenotypes, phagocytize toxic molecules, secrete pro-inflammatory/anti-inflammatory factors, promotes tissue repair, and maintain the homeostasis in CNS. Accumulation of myelin debris in multiple sclerosis (MS)/experimental autoimmune encephalomyelitis (EAE) inhibits remyelination by decreasing the phagocytosis by microglia and prevent the recovery of MS/EAE. Drug induced microglia phagocytosis could be a novel therapeutic intervention for the treatment of MS/EAE. But the abnormal phagocytosis of neurons and synapses by activated microglia will lead to neuronal damage and degeneration. It indicates that the phagocytosis of microglia has many beneficial and harmful effects in central neurodegenerative diseases. Therefore, simply promoting or inhibiting the phagocytic activity of microglia may not achieve ideal therapeutic results. However, limited reports are available to elucidate the microglia mediated phagocytosis and its underlying molecular mechanisms. On this basis, the present review describes microglia-mediated phagocytosis, drug-induced microglia phagocytosis, molecular mechanism, and novel approach for MS/EAE treatment.

[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.

Association between clustering of cardiovascular risk factors and resting heart rate in Chinese population: a cross-sectional study.

BACKGROUND: Epidemiologic studies have explored the association between a single cardiovascular risk factor (CVRF) and resting heart rate (RHR), but the research on the relation of multiple risk factors with RHR remains scarce. This study aimed to explore the associations between CVRFs clustering and the risk of elevated RHR. METHODS: In this cross-sectional study, adults aged 35-75 years from 31 provinces were recruited by the China PEACE Million Persons Projects from September 2015 to August 2020. We focused on seven risk factors: hypertension, diabetes mellitus, dyslipidemia, obesity, smoking, alcohol use, and low physical activity. Multivariate logistic regression was used to calculate odds ratios (OR) for elevated RHR (> 80 beats/min). RESULTS: Among 1,045,405 participants, the mean age was 55.67 ± 9.86 years, and 60.4% of participants were women. The OR (95% CI) for elevated RHR for the groups with 1, 2, 3, 4 and ≥ 5 risk factor were 1.11 (1.08-1.13), 1.36 (1.33-1.39), 1.68 (1.64-1.72), 2.01 (1.96-2.07) and 2.58 (2.50-2.67), respectively (P trend < 0.001). The association between the CVRFs clustering number and elevated RHR was much more pronounced in young males than in other age-sex subgroups. Clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR than those comprising more behavioral risk factors. CONCLUSIONS: There was a significant positive association between the CVRFs clustering number and the risk of elevated RHR, particularly in young males. Compared clusters comprising more behavioral risk factors, clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR. RHR may serve as an indicator of the cumulative effect of multiple risk factors.

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.

Astrocytes: a double-edged sword in neurodegenerative diseases.

Astrocytes play multifaceted and vital roles in maintaining neurophysiological function of the central nervous system by regulating homeostasis, increasing synaptic plasticity, and sustaining neuroprotective effects. Astrocytes become activated as a result of inflammatory responses during the progression of pathological changes associated with neurodegenerative disorders. Reactive astrocytes (neurotoxic A1 and neuroprotective A2) are triggered during disease progression and pathogenesis due to neuroinflammation and ischemia. However, only a limited body of literature describes morphological and functional changes of astrocytes during the progression of neurodegenerative diseases. The present review investigated the detrimental and beneficial roles of astrocytes in neurodegenerative diseases reported in recent studies, as these cells have promising therapeutic potential and offer new approaches for treatment of neurodegenerative diseases.

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.

In vivo Two-Photon Imaging Reveals Acute Cerebral Vascular Spasm and Microthrombosis After Mild Traumatic Brain Injury in Mice.

Mild traumatic brain injury (mTBI), or concussion, is reported to interfere with cerebral blood flow and microcirculation in patients, but our current understanding is quite limited and the results are often controversial. Here we used longitudinal in vivo two-photon imaging to investigate dynamic changes in cerebral vessels and velocities of red blood cells (RBC) following mTBI. Closed-head mTBI induced using a controlled cortical impact device resulted in a significant reduction of dwell time in a Rotarod test but no significant change in water maze test. Cerebral blood vessels were repeatedly imaged through a thinned skull window at baseline, 0.5, 1, 6 h, and 1 day following mTBI. In both arterioles and capillaries, their diameters and RBC velocities were significantly decreased at 0.5, 1, and 6 h after injury, and recovered in 1 day post-mTBI. In contrast, decreases in the diameter and RBC velocity of venules occurred only in 0.5-1 h after mTBI. We also observed formation and clearance of transient microthrombi in capillaries within 1 h post-mTBI. We concluded that in vivo two-photon imaging is useful for studying earlier alteration of vascular dynamics after mTBI and that mTBI induced reduction of cerebral blood flow, vasospasm, and formation of microthrombi in the acute stage following injury. These changes may contribute to early brain functional deficits of mTBI.