PrP 106-126 Altered PrP mRNA Gene Expression in Mouse Microglia BV-2 Cells

Prion diseases are infectious and fatal neurodegenerative diseases.The pathogenic agent is an abnormal prion protein aggregate.Microglial activation in the centre nervous system is a characteristic feature of prion disease.In this study,we examined the effect of PrP 106-126 on PrP mRNA gene expression in Mouse microglia cells BV-2 by real-time quantitative PCR.PrP mRNA expression level was found to be significantly increased after 18 h exposure of BV-2 cells to PrP 106-126,with 3-fold increase after 18 h and 4.5-fold increase after 24 h and BV-2 cells proliferating occurred correspondingly.Our results provide the first in vitro evidence of the increase of PrP mRNA levels in microglial cells exposed to PrP 106-126,and indicate that microglial cells might play a critical role in prion pathogenesis.

Inhibition of glycolysis mitigate microglial-activation mediated neuroinflammation in vitro and in vivo

OBJECTIVE Microglial activation-mediated neuroinflammation plays an important pathological basis in the progression of many neurodegenerative diseases.Activated microglia cells show a metabolic shift from oxidative phos⁃phorylation to aerobic glycolysis.However,the molecular mechanism underlying the role of glycolysis in microglial activation and progres⁃sion of neuroinflammatory diseases have not yet been fully understood.METHODS The anti-inflammatory effects and its underlying mecha⁃nisms of glycolytic inhibition in vitro were exam⁃ined in lipopolysaccharide(LPS)activated BV-2 microglial cells or primary microglial cells by enzyme-linked immunosorbent assay(ELISA),quantitative reverse transcriptase polymerase chain reaction(RT-PCR),Western blotting,immunoprecipitation,Flow cytometry and nuclear factor kappa B(NF-κB)luciferase reporter assays.In vivo,the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-or LPS-induced Par⁃kinson disease(PD)models were constructed to explored the anti-inflammatory and neuropro⁃tective effects of glycolytic inhibitor.RESULTS Inhibition of glycolysis by specific inhibitors[2-DG and 3-bromopyruvic acid(3-BPA)],knockdown of glucose transporter type 1(Glut-1)or hexoki⁃nase(HK)Ⅱabolished LPS-induced expres⁃sion of proinflammatory genes in microglia cells.Mechanistic studies demonstrated that glyco⁃lytic inhibitors significantly inhibited LPS-induced mTOR phosphorylation,IKKβphosphorylation,IκB phosphorylation,IκB degradation,nuclear translocation of P65 and NF-κB luciferase activity.Furthermore,LPS-induced P65 acetyla⁃tion on lysine 310,which is mediated by NAD-dependent protein deacetylase sirtuin-1 and is critical for NF-kB activation,were inhibited by glycolytic inhibitors.A coculture study revealed that 2-DG reduced the cytotoxicity of activated microglia toward MES23.5 dopaminergic neuron cells with no direct protective effect.In vivo,2-DG significantly ameliorated MPTP or LPS induced DA neuron loss and glial cell activation.CONCLUSION Glycolysis is actively involved in microglial activation.Inhibition of glycolysis can ameliorate microglial activation-related neuroinflammatory diseases.

Effect of glial cells on remyelination after spinal cord injury

Remyelination plays a key role in functional recovery of axons after spinal cord injury.Glial cells are the most abundant cells in the central nervous system.When spinal cord injury occurs,many glial cells at the lesion site are immediately activated,and different cells differentially affect inflammatory reactions after injury.In this review,we aim to discuss the core role of oligodendrocyte precursor cells and crosstalk with the rest of glia and their subcategories in the remyelination process.Activated astrocytes influence proliferation,differentiation,and maturation of oligodendrocyte precursor cells,while activated microglia alter remyelination by regulating the inflammatory reaction after spinal cord injury.Understanding the interaction between oligodendrocyte precursor cells and the rest of glia is necessary when designing a therapeutic plan of remyelination after spinal cord injury.

Gastrodin inhibits neuroinflammation in rotenone-induced Parkinson's disease model rats

The present study showed that the latency of rats moving on a vertical grid was significantly prolonged, and the number of rats sliding down from the declined plane was increased remarkably, in rotenone-induced Parkinson＇s disease model rats compared with control rats. The moving latency recovered to normal levels, but the number of slides was significantly increased at 28 days after model establishment. The slope test is a meaningful approach to evaluate the symptoms of Parkinson＇s disease model rats treated with rotenone. In addition, loss of substantia nigral dopaminergic neurons in model rats was observed at 1 day after the model was established, and continued gradually at 14 and 28 days. The expression of tyrosine hydroxylase-positive cells was significantly increased in gastrodin-treated rats at 14 days. Significant numbers of activated microglia cells were observed in model rats at 14 and 28 days; treatment of rats with Madopar at 28 days suppressed microglial activation. Treatment of rats with gastrodin or Madopar at 28 days significantly reduced interleukin-1β expression. The loss of substantia nigral dopaminergic neurons paralleled the microglial activation in Parkinson＇s disease model rats treated with rotenone. The inflammatory factors tumor necrosis factor-a and interleukin-1β are involved in the substantia nigral damage. Gastrodin could protect dopaminergic neurons via inhibition of interteukin-1β expression and neuroinflammation in the substantia nigra.

Effects of TYROBP Deficiency on Neuroinflammation of a Alzheimer’s Disease Mouse Model Carrying a PSEN1 p.G378E Mutation

Objective To study the effects of TYRO protein kinase-binding protein(TYROBP)deficiency on learning behavior,glia activation and pro-inflammatory cycokines,and Tau phosphorylation of a new Alzheimer’s disease(AD)mouse model carrying a PSEN1 p.G378E mutation.Methods A new AD mouse model carrying PSEN1 p.G378E mutation was built based on our previously found AD family which might be ascribed to the PSEN1 mutation,and then crossed with TYROBP deficient mice to produce the heterozygous hybrid mice(PSEN1^(G378E)/WT;Tyrobp^(+/-))and the homozygous hybrid mice(PSEN1^(G378E/G378E);Tyrobp^(-/-)).Water maze test was used to detect spatial learning and memory ability of mice.After the mice were sacrificed,the hippocampus was excised for further analysis.Immunofluorescence was used to identify the cell that expresses TYROBP and the number of microglia and astrocyte.Western blot was used to detect the expression levels of Tau and phosphorylated Tau(p-Tau),and ELISA to measure the levels of pro-inflammatory cytokines.Results Our results showed that TYROBP specifically expressed in the microglia of mouse hippocampus.Absence of TYROBP in PSEN1^(G378E) mutation mouse model prevented the deterioration of learning behavior,decreased the numbers of microglia and astrocytes,and the levels of interleukin-6,interleukin-1βand tumor necrosis factor-αin the hippocampus(all P<0.05).The ratios of AT8/Tau5,PHF1/Tau5,pT181/Tau5,pT231/Tau5 and p-ERK/ERK were all higher in homozygous hybrid mice(PSEN1^(G378E/G378E);Tyrobp^(-/-) mice)compared with PSEN1^(G378E/G378E) mice(all P<0.05).Conclusions TYROBP deficiency might play a protective role in the modulation of neuroinflammation of AD.However,the relationship between neuroinflammation processes involving microglia and astrocyte activation,and release of pro-inflammatory cytokines,and p-Tau pathology needs further study.

Connecting Malfunctioning Glial Cells and Brain Degenerative Disorders

The DNA damage response（DDR） is a complex biological system activated by different types of DNA damage.Mutations in certain components of the DDR machinery can lead to genomic instability disorders that culminate in tissue degeneration,premature aging,and various types of cancers.Intriguingly,malfunctioning DDR plays a role in the etiology of late onset brain degenerative disorders such as Parkinson＇s,Alzheimer＇s,and Huntington＇s diseases.For many years,brain degenerative disorders were thought to result from aberrant neural death.Here we discuss the evidence that supports our novel hypothesis that brain degenerative diseases involve dysfunction of glial cells（astrocytes,microglia,and oligodendrocytes）.Impairment in the functionality of glial cells results in pathological neuro-glial interactions that,in turn,generate a ‘‘hostile＂ environment that impairs the functionality of neuronal cells.These events can lead to systematic neural demise on a scale that appears to be proportional to the severity of the neurological deficit.

针刺调节小胶质细胞活化治疗阿尔茨海默病:神经炎症机制研究进展

Microglia(MG)activation and its mediated neuroinflammation are closely related to the occurrence and deterioration of Alzheimer's disease(AD).Acupuncture is one of the effective approach for AD,which can relieve the symptoms and slow the deterioration of AD.Based on the role of MG activation and its induced pro-inflammatory and anti-inflammatory phenotypes in neuroinflammation,this paper reviews the related literature on the mechanism of acupuncture in regulating MG activation and relieving neuroinflammation in AD.It is found that acupuncture can inhibit abnormal MG activation by regulating the release of MG surface immune receptors and pro-inflammatory/anti-inflammatory cytokines.It can also modulate the activity of signaling pathways associated with MG polarization,downregulate the expression of Ml,and promote MG polarization towards the M2 phenotype.Additionally,it adjusts the imbalance between M1 and M2 phenotypes of MG,thereby relieving the neuroinflammatory pathological procession of and repairing the neuronal damage so as to achieve its therapeutic effect.

DGMI alleviates OGD/R-induced cell injury by regulating inflammatory and apoptosis signaling pathways

Diterpene ginkgolides meglumine injection(DGMI),a kind of Ginkgo biloba special extract injection,is now used for the treatment of ischemic stroke in convalescence.In the present study,we aimed to confirm whether DGMI could suppress inflammatory responses and apoptosis and explore the potential mechanisms underlying these effects.Cell viability and lactate dehydrogenase(LDH)release were measured by MTS and LDH assays after the cells were exposed to oxygen-glucose deprivation/reoxygenation(OGD/R).The extent of anti-apoptotic effect of DGMI was detected by flow cytometry using Annexin V-FITC/PI double staining assay kit.Pro-inflammatory cytokines,including TNF-α,IL-1β,IL-6 and IL-10,were quantified by a specific Bio-Plex ProTM Reagent Kit.Additionally,activities of TLR2/4,NF-κB p65,MAPK pathway and apoptosis-related proteins as well as cellular localization of NF-κB p65 were determined by Western blotting analysis and immunofluorescence staining,respectively.DGMI at 50μg/mL significantly increased the cell viability and decreased the secretion of IL-1β,IL-6,IL-10 and TNF-αin OGD/R-induced BV2 microglia cells.These effects were also confirmed by LDH assay and Annexin V-FITC/PI staining.Meanwhile,DGMI not only inhibited the protein expressions of TLR2,TLR4,MyD88,p-TAK1,p-IkBα,p-IKKβand Bak,but also decreased the cleaved caspase-3/caspase-3,Bax/Bcl-2 and cleaved PARP-1/PARP-1 ratio in OGD/R-induced BV2 microglia cells.Furthermore,OGD/R-enhanced p-JNK1/2 and p-p38 MAPK expressions and nuclear translocation of NF-κB p65 were also partially inhibited by DGMI.The present study showed that inflammatory responses were triggered in BV2 microglia cells activated by OGD/R,leading to the release of pro-inflammatory cytokines and apoptosis.DGMI suppressed the inflammatory response and apoptosis by regulating the TLR/MyD88/NF-κB signaling pathways and down-regulation of p-JNK1/2 and p-p38 MAPK activation.

Effect of tetrahedral DNA nanostructures on LPS-induced neuroinflammation in mice

Neuroinflammation plays a significant role in inducing depression-like behavior. Tetrahedral DNA nanostructures(TDNs) are molecules that exhibit anti-inflammatory properties and can effectively penetrate the blood-brain barrier. Thus, researchers have hypothesized that TDNs regulate the secretion of proinflammatory cytokines and consequently alleviate depression-like behavior. To test this hypothesis, we investigated the effect of TDNs on the depression-like behavior of C57 mice induced by lipopolysaccharide(LPS). We performed open-field, tail suspension, and sucrose preference tests on LPS-and LPS/TDNtreated mice. The results indicated that the injection of TDNs into LPS-treated mice resulted in increased velocity, center zone duration, frequency to the center zone, and sucrose preference, and decreased immobility time. Immunofluorescence results indicated that peripheral administration of LPS in the mice activated inflammation, which culminated in distinct depression-like behavior. However, TDNs effectively alleviated the inflammation and depression-like behavior through the reduction of the expression levels of proinflammatory cytokines, such as interleukin-1β and tumor necrosis factor-α in the brain. Additionally, TDNs normalized the expression level of microglia cell activation markers, such as ionized calcium binding adaptor molecule 1, in the hippocampus of mice. These results indicated that TDNs attenuated the LPS-induced secretion of inflammatory factors and consequently alleviated depression-like behavior.