Decoding the Cellular Trafficking of Prion-like Proteins in Neurodegenerative Diseases / 神经科学通报·英文版

The accumulation and spread of prion-like proteins is a key feature of neurodegenerative diseases (NDs) such as Alzheimer's disease, Parkinson's disease, or Amyotrophic Lateral Sclerosis. In a process known as 'seeding', prion-like proteins such as amyloid beta, microtubule-associated protein tau, α-synuclein, silence superoxide dismutase 1, or transactive response DNA-binding protein 43 kDa, propagate their misfolded conformations by transforming their respective soluble monomers into fibrils. Cellular and molecular evidence of prion-like propagation in NDs, the clinical relevance of their 'seeding' capacities, and their levels of contribution towards disease progression have been intensively studied over recent years. This review unpacks the cyclic prion-like propagation in cells including factors of aggregate internalization, endo-lysosomal leaking, aggregate degradation, and secretion. Debates on the importance of the role of prion-like protein aggregates in NDs, whether causal or consequent, are also discussed. Applications lead to a greater understanding of ND pathogenesis and increased potential for therapeutic strategies.

Research advances in the role of Rab GTPases in Alzheimer's disease / 生理学报

Extracellular deposition of β-amyloid (Aβ) and intracellular hyperphosphorylated tau are the predominant pathological changes in Alzheimer's disease (AD). Increasing evidence demonstrates a critical role of a variety of small GTPases, namely Ras-related proteins (Rabs), in the pathogenesis of AD. As crucial regulators of intracellular membrane trafficking, alteration in Rab protein expression and function represents one of the primary factors contributing to the abnormal membrane trafficking in AD. Additionally, the Rab GTPases are also involved in the development of Aβ, tau and other pathological changes associated with AD. In this article, we conduct a comprehensive review on the primary functions of multiple Rab proteins and their involvement in the pathogenesis of AD.

Effects of Yizhi Tiaoshen acupuncture on learning and memory function and the expression of phosphorylated tau protein in the hippocampus of Alzheimer's disease model rats / 中国针灸

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.

Accuracy of the brief cognitive screening battery for diagnosing Alzheimer's disease defined by cerebrospinal fluid biomarkers and AT(N) classification: a case-control study / Acurácia da bateria breve de rastreio cognitivo no diagnóstico da doença de Alzheimer definida por biomarcadores no líquido cefalorraquidiano e classificação pelo sistema AT(N): estudo caso-controle

ABSTRACT Background: Validation of cognitive instruments for detection of Alzheimer's disease (AD) based on correlation with diagnostic biomarkers allows more reliable identification of the disease. Objectives: To investigate the accuracy of the Brief Cognitive Screening Battery (BCSB) in the differential diagnosis between AD, non-AD cognitive impairment (both defined by cerebrospinal fluid [CSF] biomarkers) and healthy cognition, and to correlate CSF biomarker results with cognitive performance. Methods: Overall, 117 individuals were evaluated: 45 patients with mild cognitive impairment (MCI) or mild dementia within the AD continuum defined by the AT(N) classification [A+T+/-(N)+/]; 27 non-AD patients with MCI or mild dementia [A-T+/-(N)+/-]; and 45 cognitively healthy individuals without CSF biomarker results. All participants underwent evaluation using the BCSB. Results: The total BCSB and delayed recall (DR) scores of the BCSB memory test showed high diagnostic accuracy, as indicated by areas under the ROC curve (AUC): 0.89 and 0.87, respectively, for discrimination between AD and non-AD versus cognitively healthy controls. Similarly, total BCSB and DR displayed high accuracy (AUC-ROC curves of 0.89 and 0.91, respectively) for differentiation between AD and controls. BCSB tests displayed low accuracy for differentiation between AD and non-AD. The CSF levels of biomarkers correlated significantly, though weakly, with DR. Conclusions: Total BCSB and DR scores presented good accuracy for differentiation between patients with a biological AD diagnosis and cognitively healthy individuals, but low accuracy for differentiating AD from non-AD patients.

RESUMO Antecedentes: A validação de testes cognitivos para identificação da doença de Alzheimer (DA) definida por biomarcadores aumenta a confiabilidade diagnóstica. Objetivos: Investigar a acurácia da Bateria Breve de Rastreio Cognitivo (BBRC) no diagnóstico diferencial entre DA, comprometimento cognitivo não-DA (ambos diagnósticos definidos por biomarcadores no líquido cefalorraquidiano-LCR) e indivíduos cognitivamente saudáveis, e investigar correlações entre desempenho nos testes e concentrações dos biomarcadores no LCR. Métodos: No total, 117 indivíduos foram avaliados. Quarenta e cinco pacientes com comprometimento cognitivo leve (CCL) ou demência leve com diagnóstico do continuum de DA definido pela classificação AT(N) [A+T+/-(N)+/-], 27 pacientes com CCL ou demência leve não-DA [A-T+/-(N)+/-], e 45 controles cognitivamente saudáveis sem estudo de biomarcadores no LCR. Os participantes foram submetidos à BBRC. Resultados: O escore total da BBRC e a evocação tardia (ET) no teste de memória da BBRC apresentaram elevada acurácia diagnóstica na diferenciação entre DA e não-DA versus controles, indicada pelas áreas sob a curva ROC (AUC) de 0,89 e 0,87, respectivamente. De modo semelhante, o escore total da BBRC e a ET mostraram elevadas acurácias (AUC-ROC de 0,89 e 0,91, respectivamente) para o diagnóstico diferencial entre DA e controles. A acurácia da BBRC foi baixa na diferenciação entre DA e não-DA. Os níveis dos biomarcadores no LCR se correlacionaram de forma significativa, embora fraca, com ET. Conclusões: Os escores totais da BCSB e a ET apresentaram boa acurácia na diferenciação entre pacientes com diagnóstico biológico de DA e controles cognitivamente saudáveis, mas baixa acurácia para diferenciar DA de não-DA.

Effects of TYROBP Deficiency on Neuroinflammation of a Alzheimer's Disease Mouse Model Carrying a PSEN1 p.G378E Mutation / 中国医学科学杂志(英文版)

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 (PSEN1G378E/WT; Tyrobp+/-) and the homozygous hybrid mice (PSEN1G378E/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 PSEN1G378E mutation mouse model prevented the deterioration of learning behavior, decreased the numbers of microglia and astrocytes, and the levels of interleukin-6, interleukin-1β and tumor necrosis factor-α in 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 (PSEN1G378E/G378E; Tyrobp-/- mice) compared with PSEN1G378E/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.

Ershiwuwei Shanhu Pills regulate Akt/mTOR/GSK-3β signaling pathway to alleviate Alzheimer's disease mice / 中国中药杂志

The present study investigated the mechanism of the Tibetan patent medicine Ershiwuwei Shanhu Pills(ESP) in alleviating Alzheimer's disease in mice via Akt/mTOR/GSK-3β signaling pathway. BALB/c mice were randomly assigned into a blank control group, a model group, low(200 mg·kg~(-1)), medium(400 mg·kg~(-1)) and high(800 mg·kg~(-1)) dose groups of ESP, and donepezil hydrochloride group. Except the blank control group, the other groups were given 20 mg·kg~(-1) aluminum chloride by gavage and 120 mg·kg~(-1) D-galactose by intraperitoneal injection for 56 days to establish Alzheimer's disease model. Morris water maze was used to detect the learning and memory ability of mice. The level of p-tau protein in mouse hippocampus and the levels of superoxide dismutase(SOD), malondialdehyde(MDA), catalase(CAT), and total antioxidant capacity(T-AOC) in hippocampus and serum were detected. Hematoxylin-eosin staining and Nissl staining were performed for the pathological observation of whole brain in mice. TdT-mediated dUTP nick-end labeling(TUNEL) staining was employed for the observation of apoptosis in mouse cortex. Western blot was adopted to detect the protein levels of p-mTOR, p-Akt, and GSK-3β in the hippocampus. Compared with the model group, the ESP groups showcased alleviated pathological damage of the whole brain, decreased TUNEL positive cells, reduced level of p-tau protein in hippocampus, and risen SOD, CAT, and T-AOC levels and declined MDA level in hippocampus and serum. Furthermore, the ESP groups had up-regulated protein levels of p-mTOR and p-Akt while down-regulated protein level of GSK-3β in hippocampus. Therefore, ESP can alleviate the learning and memory decline and oxidative damage in mice with Alzheimer's disease induced by D-galactose combined with aluminum chloride, which may be related to Akt/mTOR/GSK-3β signaling pathway.

Current Alzheimer disease research highlights: evidence for novel risk factors / 中华医学杂志(英文版)

Alzheimer disease (AD) is the most common type of dementia characterized by the progressive cognitive and social decline. Clinical drug targets have heavily focused on the amyloid hypothesis, with amyloid beta (Aβ), and tau proteins as key pathophysiologic markers of AD. However, no effective treatment has been developed so far, which prompts researchers to focus on other aspects of AD beyond Aβ, and tau proteins. Additionally, there is a mounting epidemiologic evidence that various environmental factors influence the development of dementia and that dementia etiology is likely heterogenous. In the past decades, new risk factors or potential etiologies have been widely studied. Here, we review several novel epidemiologic and clinical research developments that focus on sleep, hypoxia, diet, gut microbiota, and hearing impairment and their links to AD published in recent years. At the frontiers of AD research, these findings and updates could be worthy of further attention.

Chronic sleep deprivation exacerbates cognitive and pathological impairments in APP/PS1/tau triple transgenic Alzheimer's disease model mice / 生理学报

Sleep exerts important functions in the regulation of cognition and emotion. Recent studies have found that sleep disorder is one of the important risk factors for Alzheimer's disease (AD), but the effects of chronic sleep deprivation on the cognitive functions of AD model mice and its possible mechanism are still unclear. In the present study, 8-month-old male APP/PS1/tau triple transgenic AD model (3xTg-AD) mice and wild type (WT) mice (n = 8 for each group) were subjected to chronic sleep deprivation by using the modified multiple platform method, with 20 h of sleep deprivation each day for 21 days. Then, open field test, elevated plus maze test, sugar water preference test, object recognition test, Y maze test and conditioned fear memory test were performed to evaluate anxiety- and depression-like behaviors, and multiple cognitive functions. In addition, the immunohistochemistry technique was used to observe pathological characteristics in the hippocampus of mice. The results showed that: (1) Chronic sleep deprivation did not affect anxiety- (P = 0.539) and depression-like behaviors (P = 0.874) in 3xTg-AD mice; (2) Chronic sleep deprivation exacerbated the impairments of object recognition memory (P < 0.001), working memory (P = 0.002) and the conditioned fear memory (P = 0.039) in 3xTg-AD mice; (3) Chronic sleep deprivation increased amyloid β (Aβ) deposition (P < 0.001) and microglial activation (P < 0.001) in the hippocampus of 3xTg-AD mice, without inducing abnormal tau phosphorylation and neurofibrillary tangles. These results indicate that chronic sleep deprivation exacerbates the impairments of recognition memory, working memory and conditioned fear memory in 3xTg-AD mice by aggravating Aβ deposition and the excessive activation of microglia in the hippocampus.

Genetic Prion Disease: Insight from the Features and Experience of China National Surveillance for Creutzfeldt-Jakob Disease / 神经科学通报·英文版

Human genetic prion diseases (gPrDs) are directly associated with mutations and insertions in the PRNP (Prion Protein) gene. We collected and analyzed the data of 218 Chinese gPrD patients identified between Jan 2006 and June 2020. Nineteen different subtypes were identified and gPrDs accounted for 10.9% of all diagnosed PrDs within the same period. Some subtypes of gPrDs showed a degree of geographic association. The age at onset of Chinese gPrDs peaked in the 50-59 year group. Gerstmann-Sträussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI) cases usually displayed clinical symptoms earlier than genetic Creutzfeldt-Jakob disease (gCJD) patients with point mutations. A family history was more frequently recalled in P105L GSS and D178N FFI patients than T188K and E200K patients. None of the E196A gCJD patients reported a family history. The gCJD cases with point mutations always developed clinical manifestations typical of sporadic CJD (sCJD). EEG examination was not sensitive for gPrDs. sCJD-associated abnormalities on MRI were found in high proportions of GSS and gCJD patients. CSF 14-3-3 positivity was frequently detected in gCJD patients. Increased CSF tau was found in more than half of FFI and T188K gCJD cases, and an even higher proportion of E196A and E200K gCJD patients. 63.6% of P105L GSS cases showed a positive reaction in cerebrospinal fluid RT-QuIC. GSS and FFI cases had longer durations than most subtypes of gCJD. This is one of the largest studies of gPrDs in East Asians, and the illness profile of Chinese gPrDs is clearly distinct. Extremely high proportions of T188K and E196A occur among Chinese gPrDs; these mutations are rarely reported in Caucasians and Japanese.

Salivary biomarkers in Alzheimer´s disease / Biomarcadores salivales en la enfermedad de Alzheimer

The hypotheses currently considered the most likely causes of Alzheimer's disease (AD) are amyloid beta peptide deposition in the cerebral cortex and hyperphosphorylation of the Tau protein, with the consequent formation of neurofibrillary tangles. In clinical practice, although not accurate, AD diagnosis is based on the exclusion of other diseases, behavioural assessments and complementary examinations, such as imaging and blood tests. Advances in the field of biotechnology have created exciting prospects for the early detection of AD via biomarker assessment, which is considered a safer and more efficient procedure. Molecules recognised as biomarkers can be expressed in some body fluids, including cerebrospinal fluid, saliva and blood. The presence of amyloid beta peptide and Tau can be confirmed in saliva, which is also an easily and non-invasively collectable material with an accessible cost. The objective was evaluate the concentrations of the t-Tau protein and Ab42 peptide in the saliva of elderly individuals with and without dementia of the AD type Method: The objective of this case-control study, involving a total of 120 individuals, was to analyse whether a correlation exists between variations in the concentrations of the t-Tau and Ab42 biomarkers in the saliva of patients with confirmed AD and individuals in the inclusion group but without AD . We found that t-Tau expression in AD patients is significantly lower than that in individuals without AD, whereas the salivary concentration of Ab42 is higher in patients with AD but not significantly different from that of the group without AD. Conclusion: Thus, we demonstrate the feasibility of using salivary biomarkers as predictive markers for diagnosis of Alzheimer's disease.

Las hipótesis consideradas actualmente como las causas más probables de la enfermedad de Alzheimer (EA) son la deposición de péptido beta amiloide en la corteza cerebral y la hiperfosforilación de la proteína Tau, con la consiguiente formación de ovillos neurofibrilares. En la práctica clínica, aunque no es precisa, el diagnóstico de la EA se basa en la exclusión de otras enfermedades, evaluaciones de comportamiento y exámenes complementarios, como imágenes y análisis de sangre. Los avances en el campo de la biotecnología han creado interesantes perspectivas para la detección temprana de la EA a través de la evaluación de biomarcadores, que se considera un procedimiento más seguro y más eficiente. Las moléculas reconocidas como biomarcadores se pueden expresar en algunos fluidos corporales, incluidos el líquido cerebroespinal, la saliva y la sangre. La presencia del péptido beta amiloide (AB) y la proteína Tau (t-Tau) se puede confirmar en la saliva, que también es un material fácil y no invasivo de recolección con un costo accesible. El objetivo fue evaluar las concentraciones de la proteína t-Tau y el péptido Ab42 en la saliva de las personas de edad avanzada con y sin demencia del tipo de tipo EA. El estudio de casos y controles, se realizó en un total de 120 personas, para analizar si existe una correlación entre las variaciones en las concentraciones de los biomarcadores t-Tau y Ab42 en la saliva de pacientes con EA confirmada e individuos en el grupo de inclusión pero sin AD. Encontramos que la expresión de t-Tau en pacientes con EA es significativamente menor que en individuos sin EA, mientras que la concentración salival de Ab42 es mayor en pacientes con EA pero no significativamente diferente de la del grupo sin la enfermedad . Por lo tanto, se demuestra la viabilidad del uso de biomarcadores salivales como marcadores predictivos para el diagnóstico de la enfermedad de Alzheimer.

Effect of early intervention of electroacupuncture on learning-memory ability and level of hippocampal phosphorylated Tau protein in SAMP8 mice / 中国针灸

OBJECTIVE@#To explore the effect of early intervention electroacupuncture (EA) at "Baihui" (GV 20), "Dazhui" (GV 14) and "Shenshu" (BL 23) on the learning-memory ability and the expression of phosphorylated Tau protein in the hippocampus of SAMP8 mice, so as to provide reference for the intervening period of EA for Alzheimer's disease (AD).@*METHODS@#A total of 36 3-month old SAMP8 mice were randomly divided into a model group, a 3-month-old EA group and a 9-month-old EA group, 12 mice in each group. Twelve normal SAMR1 mice with the same age were taken as the control group. The mice in the 3-month-old EA group and 9-month-old EA group were treated with EA at "Baihui" (GV 20), "Dazhui" (GV 14) and "Shenshu" (BL 23) separately 3 months old and 9 months old (continuous wave, 2 Hz, 1.5-2 mA), 20 min each time, once a day, 8 days as a course of treatment, with an interval of 2 days between courses, totally 3 courses of treatment were given. The mice sample in each group was collected at the age of 10 months after the learning-memory ability tested by Morris water maze. The expression of phosphorylated Tau protein in the hippocampus was detected by immunohistochemistry and Western blot, and the expression of Tau mRNA was detected by real-time PCR.@*RESULTS@#Compared with the control group, in the model group, the escape latency was significantly increased (<0.01), the time of stay in the original platform quadrant and the number of crossing the platform quadrant were reduced (<0.01), and the expressions of phosphorylated Tau protein and Tau mRNA in hippocampus were increased (<0.01). Compared with the model group, in the 3-month-old EA group and 9-month-old EA group, the escape latency was significantly reduced (<0.05), the time of stay in the original platform quadrant and the number of crossing the platform quadrant were increased (<0.05), and the expressions of phosphorylated Tau protein and Tau mRNA in hippocampus were reduced (<0.05). Compared with the 9-month-old EA group, in the 3-month-old EA group, the escape latency was significantly reduced (<0.05), the time of stay in the original platform quadrant and the number of crossing the platform quadrant were increased (<0.05), and the expressions of phosphorylated Tau protein and Tau mRNA were reduced (<0.01).@*CONCLUSION@#The early EA intervention could more effectively improve the learning-memory ability and inhibit phosphorylation of Tau protein in the hippocampus of SAMP8 mice.

Spicy food consumption is associated with cognition and cerebrospinal fluid biomarkers of Alzheimer disease / 中华医学杂志(英文版)

BACKGROUND@#Recent studies suggest that a healthy diet helps to prevent the development of Alzheimer disease (AD). This study aimed to investigate whether spicy food consumption is associated with cognition and cerebrospinal fluid (CSF) biomarkers of AD in the Chinese population.@*METHODS@#We enrolled 55 AD patients and 55 age- and gender-matched cognitively normal (CN) subjects in a case-control study, as well as a cohort of 131 participants without subjective cognitive decline (non-AD) in a cross-sectional study. Spicy food consumption was assessed using the Food Frequency Questionnaire (FFQ). Associations of FFQ scores with cognition and CSF biomarkers of AD were analyzed.@*RESULTS@#In the case-control study, spicy food consumption was lower in AD patients than that in CNs (4.0 [4.0-8.0] vs. 8.0 [4.5-10.0], P < 0.001); FFQ scores were positively associated with Mini-Mental Status Examination scores in the total sample (r = 0.218, P = 0.014). In the cross-sectional study, the association between spicy food consumption and cognition levels was verified in non-AD subjects (r = 0.264, P = 0.0023). Moreover, higher FFQ scores were significantly associated with higher β-Amyloid (1-42) (Aβ42) levels and lower phospho-tau/Aβ42 and total tau/Aβ42 ratios in the CSF of non-AD subjects (P < 0.05).@*CONCLUSION@#Spicy food consumption is closely related to higher cognition levels and reversed AD biomarkers in the CSF, suggesting that a capsaicin-rich diet might have the potential to modify the cognitive status and cerebral pathologies associated with AD.

Down-regulation of Protein Phosphatase 2A Catalytic Subunit Involved in Mitochondria Fission/fusion Dynamics Imbalance and Functional Impairment Induced by Human tau / 中国医学科学院学报

To explore whether the downregulation of protein phosphatase 2A catalytic subunit(PP2Ac)involved in the pathogenesis of mitochondria fission/fusion dynamics and functional imbalance induced by human tau accumulation. After cotransfection with mito-dsRed plasmids and pIRES-eGFP-tau40 plasmids 48 hours,the rat primary hippocampal neurons were observed with a laser scanning confocal microscope for their changes in shape and distribution of mitochondria.The expressions of mitochondria fission/fusion protein and PP2Ac and PP2Ab were detected by Western blotting.Furthermore,the shape and distribution of mitochondria of rat primary hippocampal neuron and wild type 293wt cells were assayed 48 hours after co-transfection with siPP2Ac-EGFP plasmids and mito-DsRed plasmids,and the fission/fusion dynamics of 293wt cells was captured with live cell time-lapse imaging after co-transfection with siPP2Ac plasmids and mito-Dendra2 plasmids.After transfection with siPP2Ac plasmids,the relative level of mitochondria fission/fusion protein of 293wt cells was assayed by Western blotting,and mitochondria membrane potential was detected by JC-1 staining,and the cellular viability was measured by CCK8 assay.Finally,the shape and distribution and membrane potential of mitochondria of HEK293 cells with stable transfection of htau40(293htau)were detected after co-transfection with PP2Ac and mito-dsRed plasmids. Human tau40 expression decreased distribution of mitochondria and significantly lowered PP2Ac level in primary hippocampal neuron(=4.814, =0.0086).Down-regulation of PP2Ac caused mitochondria elongation and perinuclear accumulation in primary hippocampal neuron and 293wt cells;in addition,down-regulation of PP2Ac in 293wt cells significantly increased mitochondria fusion rate(=2.857, =0.0074)and the levels of mitochondria fusion protein mitofusin(MFN)1(=6.768, =0.0025),MFN2(=3.121, =0.0035),and optic atrophy 1(=3.775, =0.0199);however,the levels of dynamin-like protein-1 and Fis1 remained unchanged.The down-regulation of PP2Ac in 293wt cells led to the significant decrease in mitochondria membrane potential(=2.300, =0.0270)and cell viability(=6.249, <0.0001).Finally,up-regulation of PP2Ac attenuated the abnormalities in the shape,distribution and function of mitochondria in the 293htau cells. Down-regulation of PP2Ac is involved in the abnormal shape and distribution of mitochondria and its dysfunction induced by human tau40 in rat primary hippocampal neurons and HEK293 cells.

Analysis of Tau Protein Expression in Predicting Pathological Complete Response to Neoadjuvant Chemotherapy in Different Molecular Subtypes of Breast Cancer / 한국유방암학회지

PURPOSE: Tau is a microtubule-associated protein that can be found in both normal and abnormal breast cells. Whether the expression of Tau protein can predict the response to neoadjuvant chemotherapy (NACT) is still unclear. In this study, we assessed the role of Tau protein expression in predicting a pathological complete response (pCR) to NACT for different subtypes of breast cancer.METHODS: Four hundred and sixty-eight eligible patients were retrospectively recruited in our study. The relationship between clinicopathologic factors, including Tau protein expression, and pCR in different subtypes was evaluated using logistic regression analysis. Correlation between Tau and disease-free survival (DFS) and overall survival (OS) was performed using Kaplan–Meier analysis.RESULTS: The expression of Tau protein was negatively correlated with pCR, especially in triple-negative breast cancer (TNBC). No significant difference was observed in the luminal human epidermal growth factor receptor-2 (HER2)-negative subtype and HER2-positive subtype. Patients with pCR were associated with better DFS and OS (p < 0.05). However, Tau protein expression had no association with either DFS or OS (p > 0.05).CONCLUSION: Tau protein expression can predict pCR before NACT in TNBC, but there was no correlation between Tau expression and DFS or OS.

Alzheimer's Disease Diagnosis Using Misfolding Proteins in Blood

Alzheimer's disease (AD) is pathologically characterized by a long progressive phase of neuronal changes, including accumulation of extracellular amyloid-β (Aβ) and intracellular neurofibrillary tangles, before the onset of observable symptoms. Many efforts have been made to develop a blood-based diagnostic method for AD by incorporating Aβ and tau as plasma biomarkers. As blood tests have the advantages of being highly accessible and low cost, clinical implementation of AD blood tests would provide preventative screening to presymptomatic individuals, facilitating early identification of AD patients and, thus, treatment development in clinical research. However, the low concentration of AD biomarkers in the plasma has posed difficulties for accurate detection, hindering the development of a reliable blood test. In this review, we introduce three AD blood test technologies emerging in South Korea, which have distinctive methods of heightening detection sensitivity of specific plasma biomarkers. We discuss in detail the multimer detection system, the self-standard analysis of Aβ biomarkers quantified by interdigitated microelectrodes, and a biomarker ratio analysis comprising Aβ and tau.

Correlation between CSF biomarkers of Alzheimer's disease and global cognition in a psychogeriatric clinic cohort

Objective: The relationship between biomarkers of amyloid-beta aggregation (Aβ1-42) and/or neurodegeneration (Tau protein) in cerebrospinal fluid (CSF) and cognitive decline is still unclear. We aimed to ascertain whether CSF biomarkers correlate with cognitive performance in healthy and cognitively impaired subjects, starting from clinical diagnoses. Methods: We tested for correlation between CSF biomarkers and Mini-Mental State Examination (MMSE) scores in 208 subjects: 54 healthy controls, 82 with mild cognitive impairment (MCI), 46 with Alzheimer's disease (AD), and 26 with other dementias (OD). Results: MMSE correlated weakly with all CSF biomarkers in the overall sample (r = 0.242, p < 0.0006). Aβ1-42 and MMSE correlated weakly in MCI (r = 0.247, p = 0.030), and moderately in OD (r = 0.440, p = 0.027). t-Tau showed a weak inverse correlation with MMSE in controls (r = -0.284, p = 0.043) and MCI (r = -0.241, p = 0.036), and a moderate/strong correlation in OD (r = 0.665), p = 0.0003). p-Tau correlated weakly with MMSE in AD (r = -0.343, p = 0.026) and moderately in OD (r = -0.540, p = 0.0005). The Aβ1-42/p-Tau ratio had a moderate/strong correlation with MMSE in OD (r = 0.597, p = 0.001). Conclusion: CSF biomarkers correlated best with cognitive performance in OD. t-Tau correlated weakly with cognition in controls and patients with MCI. In AD, only p-Tau levels correlated with cognitive performance. This pattern, which has been reported previously, seems to indicate that CSF biomarkers might not be reliable as indicators of disease severity.

Exosomes and their roles in neurodegenerative diseases: from pathogenic, diagnostic and therapeutical perspectives / 生理学报

Exosomes are extracellular membranous vesicles with a diameter of 30-100 nm derived from a variety of eukaryocytes. The cargo of exosomes includes proteins, lipids, nucleic acids, and substances of the cells from which they originate. They can transfer functional cargo to neighboring and distal cells, therefore contributing to intercellular communication in both physiological and pathological processes. In recent years, it was shown that exosomes in several neurodegenerative diseases are closely related to the transmission of disease-related misfolded proteins (such as α-synuclein, tau, amyloid β-protein, etc). These proteins are transported by exosomes, thus promoting the propagation to unaffected cells or areas and accelerating the progression of neurodegenerative diseases. This review focuses on the origin and composition, biological synthesis, secretion, function of exosomes, as well as their roles in the pathogenesis and progression of neurodegenerative diseases. In addition, we also discuss that exosomes can serve as biomarkers and drug delivery vehicles, and play a role in the diagnosis and treatment of neurodegenerative diseases.

Effect of rutaecarpine on Alzheimer's disease-like cognitive impairments induced by high glucose in rats / 中国应用生理学杂志

OBJECTIVE@#To investigate the effects of rutaecarpine on high glucose-induced Alzheimer's disease-like pathological and cognitive dysfunction and its mechanism in rats.@*METHODS@#Adult male SD rats were randomly divided into three groups (n=20): control group, high glucose group and rutaecarpine group. Rats in the control group were fed with conventional feed and tap water. The rats in the high glucose group were fed with conventional feed and 20% sucrose water. The rutaecarpine group was fed with fodder contain 0.01% rutaecarpine and 20% sucrose water. Morris water maze test was used to detect learning and memory and cognitive function of three groups rats after 24 weeks of feeding. Western blot analysis was used to detect tau protein at Thr205 and Ser214 sites in each group. Phosphorylation levels of GSK-3β in serine 9 site (S9-GSK-3β) and PP2A at cycline 307 site (Y307-PP2AC) were also detected. Immunohistochemistry further confirmed tau protein at Thr205 site in each group both in hippocampus and cortex.@*RESULTS@#Compared with the control group, Morris water maze results showed that the latency of finding the hidden platform of the rats in high glucose group was increased significantly and the number of crossing platforms and the target quadrant residence time were significantly decreased (all P＜0.05). Immunohistochemistry showed that the phosphorylation level of tau protein at Thr205 site was significantly increased in the high glucose group compared with the control group, and the phosphorylation level of tau protein at Thr205 site in the rutaecarpine group was higher than that in the high glucose group. Western blot analysis showed that the phosphorylation level of tau protein in the high glucose group was significantly increased at Thr205 and Ser214 site compared with the control group, but the phosphorylation level of pS9-GSK-3β was significantly decreased (all P ＜0.05). Compared with the high glucose group, the latency of finding the hidden platform of the rats in rutaecarpine group was significantly decreased, and the number of crossing platforms and the target quadrant residence time were significantly increased (both P＜0.05). Compared with the high glucose group, the phosphorylation levels of tau protein at Thr205 and Ser214 sites showed a significant decrease, but the phosphorylation level of pS9-GSK-3β was significantly increased (all P＜0.05).@*CONCLUSION@#Rutaecarpine can alleviate AD-like cognitive dysfunction induced by high glucose, possibly by enhancing pS9-GSK-3β phosphorylation, down-regulating GSK-3β activity, and thus reducing hyperphosphorylation of tau-associated sites.

Quantitative Proteomic Analysis Reveals Impaired Axonal Guidance Signaling in Human Postmortem Brain Tissues of Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a distinct neurodegenerative disease that associated with repetitive head trauma. CTE is neuropathologically defined by the perivascular accumulation of abnormally phosphorylated tau protein in the depths of the sulci in the cerebral cortices. In advanced CTE, hyperphosphorylated tau protein deposits are found in widespread regions of brain, however the mechanisms of the progressive neurodegeneration in CTE are not fully understood. In order to identify which proteomic signatures are associated with CTE, we prepared RIPA-soluble fractions and performed quantitative proteomic analysis of postmortem brain tissue from individuals neuropathologically diagnosed with CTE. We found that axonal guidance signaling pathwayrelated proteins were most significantly decreased in CTE. Immunohistochemistry and Western blot analysis showed that axonal signaling pathway-related proteins were down regulated in neurons and oligodendrocytes and neuron-specific cytoskeletal proteins such as TUBB3 and CFL1 were reduced in the neuropils and cell body in CTE. Moreover, oligodendrocyte-specific proteins such as MAG and TUBB4 were decreased in the neuropils in both gray matter and white matter in CTE, which correlated with the degree of axonal injury and degeneration. Our findings indicate that deregulation of axonal guidance proteins in neurons and oligodendrocytes is associated with the neuropathology in CTE. Together, altered axonal guidance proteins may be potential pathological markers for CTE.