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OBJECTIVE To study the effects of Dianxianqing granules on the tau protein in P301S mice by regulating mitophagy. METHODS Totally 36 P301S mice were randomly divided into model group， Dianxianqing granule group （12.48 g/kg）， donepezil hydrochloride group （positive control， 1.3 mg/kg）， with 12 mice in each group； another 10 C57BL6 mice were selected as control group. Administration groups were given relevant drug solutions intragastrically， and control group and model group were given constant volume of water intragastrically. The gavage volume was 20 mL/kg， once a day， for consecutive 5 months. During the experiment， the general condition of mice was observed in each group. After the last medication， the learning and memory ability was determined by Y maze test and Morris water maze test； HE staining was used to observe the morphological changes in brain tissue， and Nissl staining was used to observe the structure of neural cells and the number of Nissl bodies in cerebral tissue. Immunohistochemistry was used to detect the expressions of phospho-tau serine 202/threonine 205 （abbreviated as AT8） in brain tissue. Western blot assay was used to determine the expressions of mitophagy-associated proteins [PTEN-induced putative kinase-1 （PINK1）， Parkin， microtubule-associated protein 1 light chain 3B （LC3B）， p62]， synaptic-associated proteins [postsynaptic density protein-95 （PSD-95）， synaptophysin （SYP）， and growth-associated protein-43 （GAP-43）] and the phosphorylation of tau protein [expressed by the phosphorylation levels of serine 199 （Ser199） and Ser202] in brain tissue. RESULTS The mice in E-mail：lnzyxyqy2003@163.com model group showed symptoms such as white hair， decreased body mass， and lower limb paralysis， with incomplete hippocampal structures in their brain tissue， as well as incomplete cell membrane edges and cell structures； the spontaneous alternating response rate， the times of crossing platform， the number of Nissl bodies， the protein expressions of PINK1， Parkin， LC3B， SYP， GAP-43， and PSD-95 were decreased significantly， compared with control group； swimming latency （fourth and fifth day）， the protein expressions of AT8 and p62，the phosphorylation levels of Ser199 and Ser202 were increased or lengthened significantly， compared with control group （P＜0.05 or P＜0.01）. Compared with model group， the above symptoms and indexes of mice were improved significantly in administration groups （P＜0.05 or P＜0.01）. CONCLUSIONS Dianxianqing granules can effectively improve cognitive impairment in P301S mice，the mechanism of which may be associated with inducing mitochondrial autophagy， reducing the hyperphosphorylation of tau protein， up-regulating the expression of synaptic-associated proteins in brain tissue，and repairing damaged neural cells.
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ObjectiveTo investigate the effect of Danzhi Xiaoyaosan on the phosphorylation of tau protein and different sites of glycogen synthase kinase-3β （GSK-3β） and phosphoseryl/suanyl phosphate protein phosphatase 2A （PP2A） in the hippocampus of rats with Alzheimer's disease （AD） and its mechanism. MethodThe rat model of AD was established by injecting okadaic acid into the bilateral hippocampus of 90 male Wistar rats in SPF grades. The rats with successful modeling were selected and randomly divided into model group， aricept group （0.5 mg·kg-1）， and Danzhi Xiaoyaosan high， medium， and low groups （17.55， 8.77， and 4.38 g·kg-1）， and then gavaged for 42 d， once a day. Morris water maze was used to detect the learning and memory ability of rats， Nissl's staining was used to observe the morphological structure of neurons in the hippocampus， and Real-time polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression levels of tau protein， GSK-3β， and PP2A. Western blot was used to determine the protein expression levels of tau protein， GSK-3β， and PP2A. ResultAs compared with the control group， the learning and memory abilities of the rats in the model group were significantly decreased （P<0.01）， and the hippocampal CA3 region cells had abnormal structure， disorderly arrangement， and decreased number. The expression levels of GSK-3β mRNA， GSK-3β， p-GSK-3β-Tyr216， p-PP2A， and p-tau were increased in the model group as compared with the control group （P<0.01）， and those of p-GSK-3β-Ser9 and PP2A decreased significantly （P<0.01）. As compared with the model group， the learning and memory ability of the Aricept group and the Danzhi Xiaoyaosan groups were improved （P<0.05， P<0.01）， and the cell morphology and the number of hippocampal CA3 regions were better. The mRNA expression levels of PP2A and tau in the Aricept group were significantly up-regulated （P<0.05）， the mRNA expression level of GSK-3β was significantly down-regulated （P<0.01）， and the protein expression levels of GSK-3β， p-GSK-3β-Tyr216， and p-PP2A were down-regulated （P<0.05， P<0.01）， and the protein expression level of PP2A was significantly up-regulated （P<0.01）. As compared with the model group， the mRNA expression level of PP2A in the high-dose Danzhi Xiaoyaosan group was significantly up-regulated （P<0.01）， and that of GSK-3β was significantly down-regulated （P<0.01）， whereas the protein expression levels of p-PP2A， p-GSK-3β-Tyr216， and p-tau were down-regulated （P<0.05， P<0.01）， and the protein expression level of PP2A was significantly up-regulated （P<0.01）. As compared with the model group， the mRNA expression level of GSK-3β was significantly down-regulated in the medium-dose Danzhi Xiaoyaosan group （P<0.01）， the protein expression levels of GSK-3β， p-GSK-3β-Tyr216， and p-tau were down-regulated （P<0.05， P<0.01）， and the protein expression level of PP2A was significantly up-regulated （P<0.01）. As compared with the model group， the mRNA expression level of PP2A was significantly up-regulated in the low-dose Danzhi Xiaoyaosan group （P<0.01）， and that of GSK-3β was significantly down-regulated （P<0.01）， whereas the protein expression levels of GSK-3β and p-GSK-3β-Tyr216 were down-regulated （P<0.05， P<0.01）， and those of p-GSK-3β-Ser9 and PP2A were significantly up-regulated （P<0.01）. ConclusionDanzhi Xiaoyaosan can improve the learning and memory ability of rats with AD， and its mechanism may be related to the regulation of the activities of GSK-3β and PP2A protein-related sites and the phosphorylation of tau protein.
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Objective @#To investigate the effect of aluminum exposure on expression of miR-497-5p, wingless murine breast cancer virus integration site family member 3a (Wnt3a), β-catenin protein, glycogen synthase kinase-3β (GSK-3β) protein and tau protein in rat adrenal pheochromocytoma PC12 cells, so as to provide insight into unraveling the mechanisms underlying aluminum exposure-induced abnormal phosphorylation of tau protein.@* Methods@# PC12 cells were exposed to Al(mal)3 at concentrations of 0, 100, 200, 400 μmol/L for 24 h. The viability of PC12 cells was measured using cell counting kit-8 (CCK-8) assay. The relative expression of miR-497-5p and Wnt3a was detected using a real-time fluorescent quantitative PCR (RT-qPCR) assay, and the expression of Wnt3a, β-catenin, GSK-3β, P-GSK-3β (Ser9), tau and p-tau (Ser396) proteins were determined using Western blotting. @*Results @#The viability of PC12 cells appeared a tendency towards a decline with the increase of aluminum dose (Ftrend=323.473, P=0.001). RT-qPCR assay detected that the relative miR-497-5p expression appeared a tendency towards a rise with the increase of aluminum dose (Ftrend=14.888, P=0.031), and the relative Wnt3a expression appeared a tendency towards a decline with the increase of aluminum dose (Ftrend=165.934, P<0.001). The miR-497-5p expression negatively correlated with the relative Wnt3a expression (r=-0.693, P=0.012). The expression of Wnt3a (Ftrend=357.656, P=0.001), β-catenin (Ftrend=208.750, P=0.001) and p-GSK-3β (Ser9) proteins (Ftrend=512.583, P<0.001) appeared a tendency towards a decline with the increase of aluminum dose, and the expression of GSK-3β (Ftrend=39.965, P<0.001), tau (Ftrend=277.929, P=0.006) and p-tau (Ser396) proteins (Ftrend=96.247, P=0.002) appeared a tendency towards a rise with the increase of aluminum dose. @*Conclusion@# Up-regulation of miR-497-5p and GSK-3β expression and down-regulation of Wnt3a and β-catenin expression may be a mechanism underlying aluminum exposure-induced abnormal phosphorylation of tau protein.
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ObjectiveTo explore the amelioration of cognitive dysfunction in diabetes mellitus （DM） by Jianpi Qinghua prescription （JPQH） based on type 2 diabetes （T2DM） model rats. MethodFifty healthy male Wistar rats of SPF grade were randomly divided into control group （n=10） and experimental group （n=40）. The rats in the control group were fed conventionally， while those in the experimental group were fed on a high-sugar， high-fat diet for six weeks and administered with streptozotocin （STZ） for the induction of the DM model. The model rats were randomly divided into model group， sitagliptin group （1.2 g·L-1）， pioglitazone group （0.8 g·L-1）， and JPQH group （1.3 g·mL-1）， with 10 rats in each group. After six weeks of drug intervention， the changes in body weight， blood glucose， and other related indexes of each group were recorded. Enzyme-linked immunosorbent assay （ELISA） was performed to detect the levels of tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， and interleukin-6 （IL-6） in the peripheral blood and brain. The Morris water maze test was used to evaluate the cognitive function in rats. Hematoxylin-eosin （HE） staining was used to observe the pathological morphology of the hippocampal CA region. The amyloid β-protein 40 （Aβ40） level was detected by immunohistochemistry. The protein expression of t-tau and p-tau in hippocampal neurons of rats was detected by Western blot. ResultCompared with blank group， the body weight of model group was significantly decreased （P<0.05）， blood glucose level was significantly increased （P<0.01）， inflammatory cytokines TNF-α and IL-1β were increased （P<0.05）， learning and spatial ability were significantly decreased （P<0.01）， the arrangement of hippocampal cells was loose and disordered， and the intercellular space was significantly increased. The number of cells decreased significantly， and the expression of Aβ40 increased significantly. and increased t-tau and p-tau protein content in the hippocampus （P<0.01）. Compared with model group， the JPQH group showed reduced blood glucose （P<0.01）， decreased TNF-α and IL-1β levels in the peripheral blood and cerebrospinal fluid （P<0.05）， a downward trend of IL-6 without a statistical difference， improved learning and spatial memory ability （P<0.01）， densely arranged cells in the hippocampal CA1 area， increased cell number， reduced Aβ40 expression， and decreased p-tau protein expression （P<0.05）. ConclusionJPQH can prevent cognitive dysfunction in DM by reducing inflammatory factor levels， decreasing neurotoxicity caused by Aβ40 deposition， and inhibiting hyperphosphorylation of tau protein in DM rats.
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OBJECTIVE@#To explore the specific pharmacological molecular mechanisms of Kai Xin San (KXS) on treating Alzheimer's disease (AD) based on network pharmacology and experimental validation.@*METHODS@#The chemical compounds of KXS and their corresponding targets were screened using the Encyclopedia of Traditional Chinese Medicine (ETCM) database. AD-related target proteins were obtained from MalaCards database and DisGeNET databases. Key compounds and targets were identified from the compound-target-disease network and protein-protein interaction (PPI) network analysis. Functional enrichment analysis predicted the potential key signaling pathways involved in the treatment of AD with KXS. The binding affinities between key ingredients and targets were further verified using molecular docking. Finally, the predicted key signaling pathway was validated experimentally. Positioning navigation and space search experiments were conducted to evaluate the cognitive improvement effect of KXS on AD rats. Western blot was used to further examine and investigate the expression of the key target proteins related to the predicted pathway.@*RESULTS@#In total, 38 active compounds and 469 corresponding targets of KXS were screened, and 264 target proteins associated with AD were identified. The compound-target-disease and PPI networks identified key active ingredients and protein targets. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested a potential effect of KXS in the treatment of AD via the amyloid beta (A β)-glycogen synthase kinase-3 beta (GSK3 β)-Tau pathway. Molecular docking revealed a high binding affinity between the key ingredients and targets. In vivo, KXS treatment significantly improved cognitive deficits in AD rats induced by Aβ1-42, decreased the levels of Aβ, p-GSK3β, p-Tau and cyclin-dependent kinase 5, and increased the expressions of protein phosphatase 1 alpha (PP1A) and PP2A (P<0.05 or P<0.01).@*CONCLUSION@#KXS exerted neuroprotective effects by regulating the Aβ -GSK3β-Tau signaling pathway, which provides novel insights into the therapeutic mechanism of KXS and a feasible pharmacological strategy for the treatment of AD.
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Rats , Animals , Alzheimer Disease/drug therapy , Amyloid beta-Peptides , Glycogen Synthase Kinase 3 beta , Network Pharmacology , Molecular Docking Simulation , Glycogen Synthase Kinase 3/therapeutic use , Drugs, Chinese Herbal/therapeutic useABSTRACT
Based on the correlation between Qi and blood in traditional Chinese medicine， the collateral disease theory puts forward that the Qi-collateral go hand in hand with the vessel-collateral of the brain， and to be as close as lips to teeth in structure and function， which is an important basis for the function of brain governing mind. And this theory proposes that deficiency/stagnancy of collateral-Qi， stagnation of collaterals and loss of consciousness are the main pathogenesis of Alzheimer's disease（AD）， which is different from the research strategy of modern medicine focusing on neurons. It is suggested that it is necessary to treat AD from two aspects， including neuronal protection（elimination of pathological products such as β-amyloid and phosphorylated tau protein） and cerebral microvascular protection（protection of cerebral microvascular structure and function， promotion of therapeutic angiogenesis and increase of cerebral blood flow. Tongxinluo capsules is a representative drug for dredging collaterals developed under the guidance of the therapeutic principle of collaterals need circulation， it can protect microvessels and play a neuroprotective role mediated by vascular protection. Clinical studies have confirmed that Tongxinluo capsules can effectively treat AD， vascular dementia and cognitive impairment related diseases， which can provide new ideas and effective treatment ways to prevent and treat AD from neurovascular protection in a comprehensive manner.
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OBJECTIVE@#To observe the effects of Yizhi Tiaoshen (benefiting mental health and regulating the spirit) acupuncture on learning and memory function, and the expression of phosphorylated tubulin-associated unit (tau) protein in the hippocampus of Alzheimer's disease (AD) model rats, and explore the effect mechanism of this therapy on AD.@*METHODS@#A blank group and a sham-operation group were randomly selected from 60 male SD rats, 10 rats in each one. AD models were established in the rest 40 rats by the intraperitoneal injection of D-galactose and okadaic acid in the CA1 region of the bilateral hippocampus. Thirty successfully-replicated model rats were randomly divided into a model group, a western medication group and an acupuncture group, 10 rats in each one. In the acupuncture group, acupuncture was applied to "Baihui" (GV 20), "Sishencong" (EX-HN 1), "Neiguan" (PC 6), "Shenmen" (HT 7), "Xuanzhong" (GB 39) and "Sanyinjiao" (SP 6); and the needles were retained for 10 min. Acupuncture was given once daily. One course of treatment was composed of 6 days, with the interval of 1 day; the completion of treatment included 4 courses. In the western medication group, donepezil hydrochloride solution (0.45 mg/kg) was administrated intragastrically, once daily; it took 7 days to accomplish one course of treatment and a completion of intervention was composed of 4 courses. Morris water maze (MWM) and novel object recognition test (NORT) were used to assess the learning and memory function of the rats. Using HE staining and Nissl staining, the morphological structure of the hippocampus was observed. With Western blot adopted, the protein expression of the tau, phosphorylated tau protein at Ser198 (p-tau Ser198), protein phosphatase 2A (PP2A) and glycogen synthase kinase-3β (GSK-3β) in the hippocampus was detected.@*RESULTS@#There were no statistical differences in all of the indexes between the sham-operation group and the blank group. Compared with the sham-operation group, in the model group, the MWM escape latency was prolonged (P<0.05), the crossing frequency and the quadrant stay time in original platform were shortened (P<0.05), and the NORT discrimination index (DI) was reduced (P<0.05); the hippocampal cell numbers were declined and the cells arranged irregularly, the hippocampal neuronal structure was abnormal and the numbers of Nissl bodies decreased; the protein expression of p-tau Ser198 and GSK-3βwas increased (P<0.05) and that of PP2A decreased (P<0.05). When compared with the model group, in the western medication group and the acupuncture group, the MWM escape latency was shortened (P<0.05), the crossing frequency and the quadrant stay time in original platform were increased (P<0.05), and DI got higher (P<0.05); the hippocampal cell numbers were elevated and the cells arranged regularly, the damage of hippocampal neuronal structure was attenuated and the numbers of Nissl bodies were increased; the protein expression of p-tau Ser198 and GSK-3β was reduced (P<0.05) and that of PP2A was increased (P<0.05). There were no statistically significant differences in the above indexes between the acupuncture group and the western medication group (P>0.05).@*CONCLUSION@#Acupuncture therapy of "benefiting mental health and regulating the spirit" could improve the learning and memory function and alleviate neuronal injure of AD model rats. The effect mechanism of this therapy may be related to the down-regulation of GSK-3β and the up-regulation of PP2A in the hippocampus, and then to inducing the inhibition of tau protein phosphorylation.
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Male , Animals , Rats , Rats, Sprague-Dawley , Glycogen Synthase Kinase 3 beta , Tubulin , Alzheimer Disease/therapy , tau Proteins/genetics , Acupuncture Therapy , HippocampusABSTRACT
GJ-4 is crocin enrichments extracted from Gardenia jasminoides J. Ellis, and our previous studies have shown that GJ-4 significantly improved learning and memory impairment induced by Aβ in mice. Herein, a memory deficit model was developed by injecting okadaic acid (OA) into the lateral ventricle of mice, and the neuroprotection and underlying mechanism of GJ-4 on neuronal injury caused by Tau hyperphosphorylation were investigated. The Animal Care & Welfare Committee, Institute of Materia Medica, CAMS & PUMC has approved all procedures (No.00000318). GJ-4 at different doses was intragastric administration to mice for 16 days. Step-down test and Morris water maze test showed that GJ-4 could significantly improve OA-induced memory impairment in mice, and reduced the loss of Nissl bodies in the hippocampus of mice. GJ-4 could also decrease the phosphorylation level of Tau protein at Ser396, Thr231 and Ser404 via increasing protein phosphatase 2A (PP2A) activity and inhibiting glycogen synthase kinase-3β (GSK-3β) activity. Besides, further researches indicated that GJ-4 could inhibit the level of oxidative stress in the brain of OA mice, reduce neuronal apoptosis and inhibit the neuroinflammation mediated by activation of astrocytes in the hippocampus of mice, and eventually achieve its effects in improving learning and memory impairment in mice. According to these findings, we anticipated that GJ-4 might be a potential therapeutic drug for Alzheimer's disease.
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@#Introduction: The human tau protein is a key protein involved in various neurodegenerative disease (NDs) including Parkinson’s disease (PD). The protein has high tendency to aggregate into oligomers, subsequently generating insoluble mass in the brain. Symptoms of PD include tremor, bradykinesia, rigidity, and postural instability. Currently drugs for PD treatment are only symptom-targeted while effective therapeutic treatment remains a challenge. The objective of this study is to identify novel promising anti-PD drugs using computational techniques. Method: ligand-based (LB) receptor modelling was conducted using LigandScout, validated and subjected to Glide XP docking, virtual screening, ADMET, and molecular dynamics predictions. Results: The adopted LB modelling generated pharmacophoric features of 5 hydrogen bond donors, 1 aromatic rings, and 7 hydrogen bond acceptors. The validation result indicated GH score of 0.73 and EF of 36.30 as validation protocols, probing it to be an ideal model. Using 3D query of the modelling a total of 192 compounds were retrieved from interbioscreen database containing 70,436 natural compounds. Interestingly, ligands 1, 2, 3, 4 and 5 orderly indicated higher binding affinities to the receptor with Glide XP docking of -7.451, -7.368, -7.101, -6.878, and -6.789 compared to a clinical drug Anle138b with -4.552 kcal/mol respectively. Furthermore, molecular dynamics and pkCSM pharmacokinetics demonstrated ligands 1, 2, & 4 having better stability and low toxicity profiles compared to the reference. Conclusion: In summary, the study pave way for discovery of small molecules that could be recommended as adjuvant /single candidate as ant-PD candidates upon further translational study.
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Rhizoma coptidis extract has a variety of pharmacological activities, including alleviating cognitive impairment in Alzheimer's disease(AD). The main mechanisms of its anti-AD activity include reducing the production of amyloid β(Aβ), inhibiting the phosphorylation of Tau protein, inhibiting cholinesterase, anti-inflammation, anti-oxidation, improving apoptosis, etc.This paper reviewed the anti-AD effect of Rhizoma coptidis extract and the specific mechanisms, aiming to provide a theoretical basis for relevant research and clinical practice.
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El desarrollo de biomarcadores de la proteína tau para el diagnóstico temprano de la enfermedad de Alzheimer (EA) emerge como un desafío fundamental, pudiendo mejorar la efectividad de un tratamiento preventivo o que enlentezca la progresión de la enfermedad. Esta revisión analiza las evidencias que justificarían el uso de la proteína tau como biomarcador en Alzheimer preclínico. Para esto se seleccionaron artículos científicos (2011-2021) que incluyeran a la proteína tau en plasma y plaquetas como biomarcador. La presencia de la proteína tau fosforilada en el líquido cefalorraquídeo presenta limitaciones por su carácter invasivo mientras que las técnicas de imagen son costosas. La medición de tau en plaquetas se correlaciona con la severidad de la demencia, y sería útil en el seguimiento de la EA. Sin embargo, la pertinencia de su uso en la detección temprana de EA se mantiene en discusión. La presencia de proteína tau fosforilada en plasma correspondería al biomarcador con mayor nivel de desarrollo, respecto de beta amiloide. La proteína tau plasmática detecta la EA con gran precisión en casos de demencia y ha sido validada por estudios neuropatológicos. p-tau217 plasmática medida por primera vez junto a técnicas de imagen, fue importante en la etapa preclínica de EA pudiendo predecir la formación de ovillos neurofibrilares. La correlación entre especies fosforiladas de tau en plasma y EA preclínica ha sido bien establecida, por lo que su uso como biomarcador podría ser de utilidad para la comprensión del proceso fisiopatológico de la neurodegeneración y la detección temprana de EA
The development of tau protein biomarkers for the early diagnosis of Alzheimer's disease (AD) emerges as a fundamental challenge, which may improve the effectiveness of preventive treatment or slow the progression of the disease. This review analyzes the evidence that would justify the use of tau protein as a biomarker in preclinical Alzheimer's disease. For this purpose, we selected scientific articles (2011-2021) that included tau protein in plasma and platelets as a biomarker. Phosphorylated tau protein in cerebrospinal fluid has limitations due to its invasiveness, while imaging techniques are expensive. The tau measurement in platelets correlates with the severity of dementia and would be helpful in the follow-up of AD. However, the relevance of its use in the early detection of AD remains under discussion. Plasma phosphorylated tau protein would correspond to the biomarker with the highest level of development for beta-amyloid. Plasma tau protein detects AD with high accuracy in cases of dementia, and neuropathological studies validate its use. Plasma p-tau217 measured for the first time with imaging techniques was important in preclinical AD and could predict the formation of neurofibrillary tangles. The correlation between plasma phosphorylated tau species and preclinical AD is well-established, so its use as a biomarker would help understand the pathophysiological process of neurodegeneration and early AD detection.
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Mitochondrial oxidative stress has been recognized as a preliminary and critical factor that aggravates the pathological cascade of Alzheimer's disease, which induces the production of β-amyloid protein, upregulates the expression of phosphorylated tau protein and triggers oxidative damage to lipids, proteins and mitochondrial deoxyribonucleic acid. Central neurons are more vulnerable to oxidative stress than non-neuronal cells due to their high oxygen demand, abundant unsaturated fatty acids and antioxidant enzymes deficiency. On this account, this review introduces the causes of mitochondrial oxidative stress, and analyzes the important role of mitochondrial oxidative stress in the pathogenesis of Alzheimer's disease. Meanwhile, the review focuses on the design and intervention strategies of drug delivery systems targeting mitochondrial oxidative stress in neurons, aiming to provide new ideas for the prevention and treatment of Alzheimer's disease.
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With the acceleration of the aging process of our country's population, the impact of aging-related diseases - Alzheimer's disease (AD) on society and families has become increasingly prominent. AD is caused by multiple mechanisms, and the pathogenesis has not been fully elucidated. Most of the clinical treatments are single therapy, which mainly focuses on improving symptoms and are difficult to reverse the disease process. Therefore, the development of drugs that can both improve symptoms and reverse the disease process is extremely urgent in clinical. Increasing number of studies has shown that traditional Chinese medicine plays an important role in the prevention and treatment of AD. The natural products have many advantages, such as novel structures, multiple targets and diverse activities, which can be used as an important source of leading compounds for the treatment of AD. The review summarizes the main clinical treatment methods and the research progress of natural ingredients in traditional Chinese medicine, and provides a reference for the follow-up clinical treatment of AD combined with the advantages of traditional Chinese medicine treatment.
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RESUMO A doença neurodegenerativa mais comum no mundo é a doença de Alzheimer (DA), e 10% dos casos apresentam sintomas antes dos 65 anos, quase todos com associação genética, com hereditariedade autossômica dominante e penetrância entre 92 a 100% dos portadores. Na presente revisão, realizamos uma busca sobre as variantes genéticas associadas à doença de Alzheimer de início precoce (DAIP), enfatizando as características associadas mais importantes e as principais mutações já descritas. Os genes mais comumente relacionados com o surgimento da DAIP são APP, PSEN1, PSEN2 e MAPT, e mutações nestes afetam o metabolismo e a estrutura destas proteínas, resultando em acúmulos de peptídeo Aβ que causam inflamação e toxicidade no cérebro, levando à ativação da micróglia e promovendo a liberação de fatores neurotóxicos e pró-inflamatórios que aceleram a neurodegeneração. O gene PSEN1 é responsável por 70% das mutações conhecidas da DAIP, sendo a L166P associada à idade de ocorrência da doença abaixo dos 30 anos. Mutações em APP levam à agregação da proteína em placas neurodegenerativas. Todas as mutações descritas para MAPT estão associadas a um aumento dos emaranhados neurofibrilares. O polimorfismo E4 da Apolipoproteína E (APOE) influencia o aumento no risco de DAIP elevando as chances em três vezes para portadores heterozigotos e entre oito a dez vezes para os homozigotos. Apenas 5% das mutações associadas à DAIP são conhecidas, e novos estudos apresentam outros genes candidatos, bem como a importância de alterações epigenéticas na gênese desta doença.
SUMMARY The most common neurodegenerative disease in the world is Alzheimer's Disease (AD). Ten percent of Alzheimer patients experience symptoms before the age of 65, and almost all of them present genetic features of autosomal dominant inheritance nature, and penetrance of 92 to 100%. In the present review, we searched for genetic variants associated with early onset Alzheimer's disease (EOAD), emphasizing the most important characteristics and the main mutations. The genes most commonly related to the onset of EOAD are APP, PSEN1, PSEN2 and MAPT, whose mutations affect the metabolism and structure of these proteins. This process results in accumulations of Aβ peptide that leads to activation of the microglia and release of neurotoxic and pro-inflammatory factors that accelerate neurodegeneration. The PSEN1 gene is responsible for 70% of the known mutations in EOAD, while L166P is associated with below 30 years as the starting age of occurrence. APP mutations lead to protein aggregation in neurodegenerative plaques. All of the mutations described for MAPT are associated with an increase in neurofibrillary tangles. The E4 polymorphism of Apolipoprotein E (APOE) influences an increased risk of EOAD increasing up to three times the chances for heterozygous, and between eight and ten times for homozygotes carriers. Only 5% of the mutations associated with EOAD are known; new studies will show other candidate genes, as well as the importance of epigenetic factors changes in the etio-pathogenesis of this disease.
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Objective:To observe the effect of electroacupuncture at the Baihui acupoint on learning and memory ability and on the calmodulin kinase (CaMK)Ⅱ-Tau protein signal pathway in rats exposed to infrasound, and to explore its mechanism.Methods:Forty-eight Sprague-Dawley rats were randomly divided into a blank group, an infrasound group, a Baihui group and a non-acupoint group, each of 12. The rats in the blank group were placed in an infrasound chamber without infrasound for 2 hours daily. Those in the other 3 groups were exposed to 8Hz, 130dB infrasound in the chamber for 2 hours daily for 7 consecutive days. The rats in the Baihui and non-acupoint groups were given electroacupuncture within 2 hours after the infrasound exposure at the Baihui acupoint or elsewhere respectively. The rats in the blank and infrasound groups were given the same grasping and fixation, but no electroacupuncture. On the 6th and 7th day of intervention, Morris water maze positioning and navigation experiments and spatial exploration experiments were used to quantify the rats′ spatial learning and memory ability. Nissl staining was used to observe any changes in the morphology of the neurons in the hippocampus of 6 rats in each group. The expression of phosphorylated calmodulin-dependent protein kinase II (P-CaMKⅡ) and phosphorylated Tau protein (P-Tau) in the hippocampus was also documented using western blotting.Results:After 6 or 7 days the average escape latency of the rats in the infrasound group was significantly longer than the blank group′s average. Platform quadrant time and distance ratios and the number of times crossing the platform area were also significantly lower. Compared with the infrasound group, the average escape latency of the Baihui group was significantly shorter, with the platform quadrant time and distance ratios and the number of times crossing the platform area significantly higher. After 7 days, the damage to hippocampal neurons among the rats in the infrasound group was significantly aggravated and the number of neurons was reduced significantly compared with the blank group. Compared with the infrasound group, significantly fewer neurons in the hippocampus were damaged in the Baihui group and the number of neurons had increased significantly. After the intervention the levels of P-CaMKⅡand P-Tau protein in the infrasound group had increased significantly compared with the blank group, but those levels in the Baihui group were significantly lower, on average.Conclusion:Electroacupuncture at the Baihui acupoint can improve the learning and memory ability of rats exposed to infrasound, and has some protective effect against infrasound brain damage. That may be due to its inhibiting Tau protein hyperphosphorylation in the hippocampus by reducing CaMKⅡ activity.
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Alzheimer′s disease (AD), the most common neurodegenerative disease, is a major challenge in China and all the world. However, the pathogenesis of AD remains unclear, and no disease-modifying therapies are available to prevent or treat the disease. Amyloid-beta (Aβ) and hyperphosphorylated tau protein are key pathological molecules of AD. A series of clinical trials targeting Aβ, tau protein and neuroinflammation have been carried out in the past 20 years, but none of them have been successful in attenuating the cognitive decline so far. This paper discusses the challenges of the current clinical trials of AD and proposes future directions for the research of AD prevention and treatment.
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Objective:To investigate the effect of Huangjingwan （HW） on the activities of glycogen synthase kinase-3β （GSK-3β）， protein phosphatase 2A （PP2A） and the mechanism in inhibiting tau protein hyperphosphorylation in the hippocampal neurons of mice with Alzheimer's disease. Method:After subcutaneous injection with 1.0% D-galactose （0.14 g·kg-1·d-1） into the back and neck of mice for 4 weeks， the right ventricle of mice was injected with 2 μL （75 ng） of okadaic acid for one time to make AD model， and the successfully modeled AD mice were selected by Morris water maze. Then， the selected AD mice were randomly divided into AD model group， memantine group （1.3×10-3 g·kg-1·d-1） and HW group （2.5 g·kg-1·d-1）. In addition， the sham model control group and the normal control group were set up. At the same time， 2 μL normal saline was injected into the right ventricle of mouse in the sham model control group for modeling control. Two weeks after modeling， the mice in the two experimental drug groups were given the corresponding dose of the experimental drug by gavage for 4 weeks. In addition， after 2 weeks of AD modeling， mice in control group and AD model group were intragastrically administrated with the same amount of normal saline daily for 4 weeks. The mice in normal control group were only given daily feed. At the end of gavage， all the mice were tested by the open field experiment and jumping platform experiment to evaluate the differences in exploratory activity ability， anxiety level and learning and memory ability. The number of neurons in CA1 and CA3 areas of hippocampus in all the mice was detected by Nissl staining. Quantitative real-time polymerase chain reaction （Real-time PCR） was used to detect mRNA expressions of GSK-3β and PP2A in hippocampus of mice in each group. Protein expressions of GSK-3β， PP2A， phosphorylated tau （p-tau） and total tau protein （t-tau） in hippocampus of mice in each group were detected by Western blot. Result:Compared with the normal control group， mice in AD model group showed an obvious dementia state， which was characterized by a lower spontaneous activity， lower exploration behavior ability， higher anxiety level， less movement and easier to stay and hide， longer learning response time， significantly increased number of learning and memory errors， and decreased numbers of hippocampal neuron in CA1 and CA3 areas， and reduced mRNA and protein expressions of PP2A， mRNA and protein expressions of GSK-3β， p-tau protein and the ratio of p-tau/t-tau were all increased significantly （P<0.01）， while expression of t-tau protein was decreased， with no significant difference. Compared with the AD model group， mice in the HW group showed a higher spontaneous activity， higher exploration ability， lower anxiety level， higher learning and memory performance， and the numbers of hippocampal neuron in CA1 and CA3 areas increased， while mRNA and protein expressions of PP2A increased， and the mRNA and protein expressions of GSK-3β， the expression of p-tau protein and the ratio of p-tau/t-tau were all decreased significantly （P<0.01）， but with no significant difference in the protein expression of t-tau. Conclusion:HW can inhibit tau hyperphosphorylation in hippocampal neurons of AD mice， restore tau protein function， protect hippocampal neurons， and exert an anti-AD effect， which may be related to the regulatory mechanism in the activity balance between GSK-3β and PP2A in hippocampal neurons.
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Objective To optimize the synthesis method of 18F-T807 and study preliminary biodistribution. Methods 18F-T807 was synthesized using an optimized method in TRACERlab FXFN synthesizer with a t-BOC（t-Butyloxy carbonyl）-protected 18F-T807 precursor NPPI-9 as starting material, improving experimental conditions for synthesis, then QC and biodistribution study in Wistar rats conducted. Results The improved synthesis conditions increased the synthesis yield from 20.5%±6.1% to 25.7%±5.8%. QC met the standard. Wistar rats had higher intake in kidney, liver, blood and lowest intake in brain, heart, lung. Conclusion The optimized synthesis method to synthesize 18F-T807 is simple and easy, and high yield, which can meet the needs of scientific research and clinical practice.
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OBJECTIVE：To study the effects and mechanism of panaxadiol （PD） on Tau protein phosphorylation in the SH-SY5Y cells transfected with APP gene（APP-SH-SY5Y）. METHODS ：The target of PD and non-receptor tyrosine kinases Fyn was verified by molecular docking. SH-SY 5Y cells were cultured in vitro ，and the APP-SH-SY 5Y cell models and green fluorescent （GFP）-SH-SY5Y cell model （control cell ）was constructed. The expression of Aβ1-42 was detected so as to verify the success of APP-SH-SY5Y cell model. Taking GFP-SH-SY 5Y cells as control ，the effects of 5，10，20，30，40 μmol/L PD and 125，250， 500，1 000，2 000 nmol/L PP 2（Fyn inhibitor ，positive control ）on the survival rate of APP-SH-SY 5Y cells were detected by CCK-8 assay after treated for 24 h，so as to confirm the optimal concentration. The concentration of Ca 2 + ，the ratio fophosphorylated Tau protein （p-Tau）/Tau，phosphorylatedn Src（p-Src）/Fyn and phosphorylated glutamate receptor 2B（p-GluN2B）/ GluN2B were detected in APP-SH-SY 5Y cells after trated with the optimal concentration of PD and PP 2 for 24 h. RESULTS ：The results of molecular simulation docking showed that PD could target Fyn protein. Compared with GFP-SH-SY 5Y cells ，the protein expression of Aβ1-42 in APP-SH-SY 5Y cell were increased significantly （P＜0.01）. The optimal concentration of PD and PP 2 were 20 μmol/L and 500 nmol/L. The 20 μmol/L PD and 500 nmol/L PP 2 could increase the survival rate of the cells and reduced the concentration of Ca 2+，the ratio of p-Tau/Tau ，p-Src/Fyn，and p-GluN 2B/GluN2B. CONCLUSIONS：PD can reduce the the phosphorylation of Tau protein through inhibiting Fyn/GluN 2B signaling pathway.
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Objective:To explore the changes in the expression of Tau protein and phosphorylated Tau (p-Tau) protein in neurons after spinal cord ischemia-reperfusion injury (SCII).Methods:Ninety-six healthy adult SD rats were randomly divided into a sham operation group ( n=48) and a SCII group ( n=48). Based on the reperfusion time of 3 h, 6 h, 12 h, 24 h, 48 h and 72 h, the SCII group was divided into 6 subgroups ( n=8 per subgroup). Immunohistochemical staining was used to observe the apoptosis of spinal cord neurons in the L 4-L 5 segments and the expression of Tau protein and p-Tau protein. Results:In the sham operation group, the neuron cells were intact, mainly concentrated in the gray matter. Tau protein was seen in a small number of neuron cells, and a small amount of filamentous p-Tau protein in the pernucleus and cytoplasm. There was no significant difference between Tau protein and p-Tau protein expression in neurons at each time point ( P>0.05). In the SCII group, scattered Tau protein was seen in the apoptotic cells while there was a strong positive expression of Tau protein in the non-apoptotic cells. The expression of Tau protein in the SCII group gradually increased after injury, reaching a peak at 48h and plateauing at 72 h, and was significantly different between any 2 time points (except for 72 h) ( P<0.05). In the SCII group, the positive expression of p-Tau protein was observed in the cytoplasm of the apoptotic cells in strips and sheets. It increased rapidly within 6 h but did not change significantly after 6 h, showing no significant difference between any 2 time points afterwards ( P>0.05). There was a statistically significant difference in the expression of Tau protein and p-Tau protein between the SCII group and the sham operation group at each time point ( P<0.05). Conclusion:It is hopeful to reduce the severity of spinal cord injury by regulating the expression of Tau protein and p-Tau protein within 6 to 48 hours after SCII.