Tau Protein Expression Research Articles

Plasma Tumor Necrosis Factor Alpha Is a Predictor of Persisting Symptoms Post-Concussion in Children

Mild traumatic brain injury (mTBI)-associated blood proteomics have become an emerging focus in the past decade, with the U.S. Food and Drug Administration recently approving the use of a blood test to determine the necessity of a computed tomography scan after adult mTBI. We now also know that the blood proteome of children is different from that of adults, and new evidence suggests that children may take longer to recover from an mTBI. Despite this, comparatively fewer studies have analyzed changes in blood protein expression after pediatric mTBI. Concussions, an mTBI subset, often go underreported, despite the potential for post-concussive symptoms to last more than one month in up to 30% of children. In the current study, we used a multiplex immunoassay to measure blood protein expression of Apolipoprotein, enolase 2, glial fibrillary acidic protein, interleukin (IL)-1B, IL-6, IL-8, IL-10, S100 calcium-binding protein B, tau and tumor necrosis factor alpha (TNFα) at admission, one to four days, two weeks, and three months post-pediatric concussion, comparing patients with normal recovery (n = 9) with those with persisting symptoms (n = 9). We identified significant differences in IL-6 (p < 0.001) and tau (p = 0.048) protein expression across time post-injury irrespective of clinical outcome and in IL-8 protein expression (p = 0.041) across time post-injury specific to children with persisting symptoms. Significantly, we have identified an increase in TNFα protein expression at one to four days post-injury (p = 0.031) in children with persisting symptoms compared with normal recovery. To our knowledge, this is the first study to identify TNFα as a potential blood biomarker for persisting symptoms post-pediatric concussion.

Peripheral nervous system effects in the PS19 tau transgenic mouse model of tauopathy

It is well known that transgenic mice overexpressing human tau protein with P301S mutation driven by the mouse prion protein promoter show clasping and limb retraction, hunched back and paralysis, followed by inability to feed that results in death around 12 months of age. To understand these motor deficits, we have carried out rotarod tests on PS19 line and demonstrated how they worsened during aging. Then, we have analyzed if these phenotypic characteristics correlate with sciatic nerve degeneration. We first demonstrated by western blot and immunohistochemistry that the sciatic nerve expresses the transgenic tau protein; then, electron microscopy studies showed alterations in myelin, mainly a detachment of myelin lamellae at Schmidt-Lanterman clefts. Similar motor deficits and myelin alterations have been previously reported in tau knockout and overexpressing transgenic mice; taking into account that PS19 model is widely used to study tauopathies, we suggest that analyzing the expression of transgenic tau protein and myelin abnormalities in the sciatic nerve should be considered when studying some features as motor performance or survival.

Melatonin receptor stimulation by agomelatine prevents Aβ-induced tau phosphorylation and oxidative damage in PC12 cells.

PurposeAs a novel antidepressant drug, agomelatine has good therapeutic effect on the mood disorder and insomnia in Alzheimer’s disease (AD). Recent studies have shown the neuroprotective function of agomelatine, including anti-oxidative and anti-apoptosis effect. However, it remains unclear whether agomelatine exerts neuroprotection in AD. Thus, the neuroprotective effect of agomelatine against amyloid beta 25–35 (Aβ25–35)-induced toxicity in PC12 cells was evaluated in this study.MethodsThe concentration of malondialdehyde (MDA), LDH, and ROS was investigated to evaluate oxidative damage. The expression of P-tau, tau, PTEN, P-Akt, Akt, P-GSK3β, and GSK3β proteins was assessed by Western blotting. Our results demonstrated that Aβ25–35 significantly increased the content of MDA, LDH, and ROS. Meanwhile, Aβ25–35 upregulated the expression of P-tau and PTEN as well as downregulated P-Akt and P-GSK3β expression. These effects could be blocked by agomelatine pretreatment. Furthermore, luzindole, the melatonin receptor (MT) antagonist, could reverse the neuroprotective effect of agomelatine.ConclusionThe results demonstrated that antidepressant agomelatine might prevent the tau protein phosphorylation and oxidative damage induced by Aβ25–35 in PC12 cells by activating MT-PTEN/Akt/GSK3β signaling. This study provided a novel therapeutic target for AD in the future.

A Polysaccharide Extract from Maitake Culinary-Medicinal Mushroom, Grifola frondosa (Agaricomycetes) Ameliorates Learning and Memory Function in Aluminum Chloride-Induced Amnesia in Mice.

Maitake (Grifola frondosa) is an edible mushroom exhibiting high nutritional value in terms of containing health-beneficial bioactive compounds. Previously, we reported that a protein-bound polysaccharide bioactive component of G. frondosa (PGM) could enhance the expression of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR), which is critical for learning and memory. However, the potential benefits of PGM on learning and memory function have never been investigated. In the current study, we aimed to explore the beneficial effect of PGM on learning and memory function in aluminum chloride (AlCl3)-induced amnesia in mice and to explore the underlying mechanisms. Mice were intraperitoneally administered with AlCl3 (60 mg/kg/d) and PGM (5, 10, or 20 mg/kg/d) for 6 weeks consecutively, and then the Morris water maze (MWM) test was conducted to assess the learning and memory function. Hematoxylin-eosin staining was performed to observe the morphology of neurons in the hippocampal dentate gyrus (DG). The expression of p-Tau (Ser396), Tau, p-GluA1 (S845), GluA1, and brain-derived neurotrophic factor (BDNF) proteins was evaluated with western blot. We found that PGM (5 and 10 mg/kg/d) significantly improved learning and memory function and attenuated histopathological abnormalities in the hippocampal DG region in the AlCl3-treated mice. Furthermore, PGM treatment significantly enhanced the level of AMPAR and BDNF in the hippocampus, while suppressing the tau protein hyperphosphorylation at the Ser396 site. These findings indicated that PGM could significantly attenuate the AlCl3-induced amnesia through the synergistic action of its active component on tau pathology, AMPAR and BDNF signaling pathway.

Low Phytanic Acid-Concentrated DHA Prevents Cognitive Deficit and Regulates Alzheimer Disease Mediators in an ApoE-/- Mice Experimental Model.

Alzheimer’s disease (AD) is the main cause of dementia and cognitive impairment. It has been associated with a significant diminution of omega-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) levels in the brain. Clinical trials with DHA as a treatment in neurological diseases have shown inconsistent results. Previously, we reported that the presence of phytanic acid (PhA) in standard DHA compositions could be blunting DHA’s beneficial effects. Therefore, we aimed to analyze the effects of a low PhA-concentrated DHA and a standard PhA-concentrated DHA in Apolipoprotein E knockout (ApoE−/−) mice. Behavioral tests and protein expression of pro-inflammatory, pro-oxidant, antioxidant factors, and AD-related mediators were evaluated. Low PhA-concentrated DHA decreased Aβ, ß-amyloid precursor protein (APP), p-tau, Ca2+/calmodulin-dependent protein kinase II (CAMKII), caspase 3, and catalase, and increased brain derived neurotrophic factor (BDNF) when compared to standard PhA-concentrated DHA. Low PhA-concentrated DHA decreased interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α) protein expression in ApoE−/− mice when compared to standard PhA-concentrated DHA. No significant differences were found in p22phox, inducible nitric oxide synthase (iNOS), glutathione peroxidase (GPx), superoxide dismutase 1 (SOD-1), and tau protein expression. The positive actions of a low PhA-concentrated DHA were functionally reflected by improving the cognitive deficit in the AD experimental model. Therefore, reduction of PhA content in DHA compositions could highlight a novel pathway for the neurodegeneration processes related to AD.

Integrative system biology analyses of CRISPR-edited iPSC-derived neurons and human brains reveal deficiencies of presynaptic signaling in FTLD and PSP

Mutations in the microtubule-associated protein tau (MAPT) gene cause autosomal dominant frontotemporal lobar degeneration with tau inclusions (FTLD-tau). MAPT p.R406W carriers present clinically with progressive memory loss and neuropathologically with neuronal and glial tauopathy. However, the pathogenic events triggered by the expression of the mutant tau protein remain poorly understood. To identify the genes and pathways that are dysregulated in FTLD-tau, we performed transcriptomic analyses in induced pluripotent stem cell (iPSC)–derived neurons carrying MAPT p.R406W and CRISPR/Cas9-corrected isogenic controls. We found that the expression of the MAPT p.R406W mutation was sufficient to create a significantly different transcriptomic profile compared with that of the isogeneic controls and to cause the differential expression of 328 genes. Sixty-one of these genes were also differentially expressed in the same direction between MAPT p.R406W carriers and pathology-free human control brains. We found that genes differentially expressed in the stem cell models and human brains were enriched for pathways involving gamma-aminobutyric acid (GABA) receptors and pre-synaptic function. The expression of GABA receptor genes, including GABRB2 and GABRG2, were consistently reduced in iPSC-derived neurons and brains from MAPT p.R406W carriers. Interestingly, we found that GABA receptor genes, including GABRB2 and GABRG2, are significantly lower in symptomatic mouse models of tauopathy, as well as in brains with progressive supranuclear palsy. Genome wide association analyses reveal that common variants within GABRB2 are associated with increased risk for frontotemporal dementia (P < 1 × 10−3). Thus, our systems biology approach, which leverages molecular data from stem cells, animal models, and human brain tissue can reveal novel disease mechanisms. Here, we demonstrate that MAPT p.R406W is sufficient to induce changes in GABA-mediated signaling and synaptic function, which may contribute to the pathogenesis of FTLD-tau and other primary tauopathies.

Propofol combined with hypoxia induces cognitive dysfunction in immature rats via p38 pathway

To investigate the effects of propofol combined with hypoxia on cognitive function of immature rats and the possible role of p38 pathway and tau protein in mediating such effects. Ninety 7-day-old (P7) SD rats were randomized for daily intraperitoneal injection of propofol (50 mg/kg) or lipid emulsion (5.0 mL/kg) for 7 consecutive days. After each injection, the rats were placed in a warm box (38 ℃) with an oxygen concentration of 18% (hypoxia), 21% (normal air), or 50% (oxygen) until full recovery of the righting reflex. Another 90 P7 rats were similarly grouped and received intraperitoneal injections of p-p38 blocker (15 mg/kg) 30 min before the same treaments. The phosphorylated tau protein, total tau protein and p-p38 content in the hippocampus were detected using Western blotting. The spatial learning and memory abilities of the rats were evaluated with Morris water maze test. Compared with lipid emulsion, propofol injection resulted in significantly increased levels of p-p38, phosphorylated tau and total tau proteins in rats with subsequent hypoxic or normal air treatment (P &lt; 0.05), but propofol with oxygen and injections of the blocker before propofol did not cause significant changes in the proteins. Without subsequent oxygenation, the rats receiving injections of propofol, with and without prior blocker injection, all showed significantly prolonged latency time and reduced platform-crossing times and third quadrant residence time compared with the corresponding lipid emulsion groups (P &lt; 0.05). With oxygen treatment, the rats in propofoland blocker-treated groups showed no significant difference in the performance in Morris water maze test from the corresponding lipid emulsion group. The results of Morris water maze test differed significantly between blocker-propofol group and propofol groups irrespective of exposures to different oxygen levels (P &lt; 0.05), but not between the lipid emulsion and blocker group pairs with exposures to different oxygen levels. Propofol combined with hypoxia can affect the expression of tau protein through p38 pathway to impair the cognitive function of immature rats, in which oxygen plays a protective role.

Turmeric Extract Supplementation Reduces Tau Protein Level in Repetitive Traumatic Brain Injury Model.

BACKGROUND:Repetitive traumatic brain injury (RTBI) has gained much attention in this decade, especially in contact sports athletes and military personals. This injury is correlated with early neurodegenerative changes that are marked with the increased of tau protein. Turmeric extract (TE) is a well-known anti-inflammation and antioxidant that decreases tau protein expression in neurodegenerative disease.AIM:This study aimed to prove the effect of TE on tau protein level after RTBI.METHODS:Forty Sprague Dawley mice were divided into four groups, i.e. negative sham control group, the control group, and two treatment groups. A weight drop model was used by applying a 40-gram mass that was dropped from a 1-meter height onto the vertex of the head, with a total frequency of 12 times, divided into 4 days (day 0, 1, 3, and 7; 3 traumas on each day). TE was given to all treatment groups with 500 mg/kg BW doses once daily. The first treatment group had TE for seven days along the trauma. The second treatment group had pretreatment TE extract, given from seven days before first trauma and continued along the trauma protocol days. Tau protein level was measured on brain and serum using ELISA method.RESULTS:There was a significant reduction of tau protein level in both treatment groups compared to trauma group, either in serum or brain, but we also found significant differences regarding brain tau level between the treatment and pretreatment group.CONCLUSION:This study might provide evidence of with the role of pretreatment TE in RTBI.

Vitis vinifera acts as anti-Alzheimer's agent by modulating biochemical parameters implicated in cognition and memory

BackgroundAluminum a known neuro and cholinotoxin has been implicated in the pathogenesis of Alzheimer’s disease. Its exposure is associated with impairment of the memory and cognition. ObjectiveThe present study was undertaken to evaluate the anti-Alzheimer’s activity of Vitis vinifera in aluminum induced Alzheimer’s disease. Materials and methodsIn this study, we investigated the behavioral and biochemical effects of aluminum in Sprague-Dawley rats. Animals were exposed to aluminum chloride (100 mg/kg/day) orally for a period of 8 weeks. Vitis was given in doses of 250 mg/kg and 500 mg/kg for 16 weeks and the possible effects of Vitis vinifera on the expression of Tau and amyloid precursor protein were evaluated by PCR analysis and the possible activities of lipid peroxidation, inflammation and anti-cholinesterase activity were evaluated. ResultsAluminum intoxication was associated with significant impairment in learning and memory in Morris water maze test. A significant improvement was observed with Vitis vinifera in a dose dependent manner. ConclusionThe findings of the present study revealed the significant neuroprotective actions of Vitis vinifera by modifying the biochemical parameters and inhibited the mRNA expression of Amyloid Precursor Protein and Tau, which are the key pathological hallmarks of Alzheimer’s disease, which was further confirmed by histopathological observations.

Genetically Engineered iPSC-Derived FTDP-17 MAPT Neurons Display Mutation-Specific Neurodegenerative and Neurodevelopmental Phenotypes.

SummaryTauopathies such as frontotemporal dementia (FTD) remain incurable to date, partially due to the lack of translational in vitro disease models. The MAPT gene, encoding the microtubule-associated protein tau, has been shown to play an important role in FTD pathogenesis. Therefore, we used zinc finger nucleases to introduce two MAPT mutations into healthy donor induced pluripotent stem cells (iPSCs). The IVS10+16 mutation increases the expression of 4R tau, while the P301S mutation is pro-aggregant. Whole-transcriptome analysis of MAPT IVS10+16 neurons reveals neuronal subtype differences, reduced neural progenitor proliferation potential, and aberrant WNT/SHH signaling. Notably, these neurodevelopmental phenotypes could be recapitulated in neurons from patients carrying the MAPT IVS10+16 mutation. Moreover, the additional pro-aggregant P301S mutation revealed additional phenotypes, such as an increased calcium burst frequency, reduced lysosomal acidity, tau oligomerization, and neurodegeneration. This series of iPSCs could serve as a platform to unravel a potential link between pathogenic 4R tau and FTD.

Effects of diesel exhaust particles on the expression of tau and autophagy proteins in human neuroblastoma cells

Particulate air pollution is recognized as a potential risk factor for neurological disorders; however, the underlying mechanisms of neurodegenerative diseases that occur due to particulate air pollution remain unclear. The objective of the present study was to evaluate the neurotoxic effects caused by diesel exhaust particles (DEPs). We determined the ability of DEPs and carbon black (CB) to induce neurotoxicity, oxidative stress and inflammation, and to disrupt the expression of tau and autophagy proteins in human neuroblastoma IMR-32 cells. Spherical CB (dominated by C, N, and S) and DEPs (dominated by C, N, and O) in aggregates were observed using a field emission-scanning electron microscope (FE-SEM) equipped with energy-dispersive x-ray (EDX) microanalysis. Cell viability was significantly decreased by CB and DEPs in IMR-32 cells, but neither particle altered malondialdehyde (MDA) production. We observed that exposure to DEPs significantly increased 8-isoprostane and tumor necrosis factor (TNF)-α levels. Significantly increased expression of tau was induced in IMR-32 cells by DEPs but not by CB. Expression of beclin 1 was increased by DEPs, whereas the light chain 3II (LC3II)/LC3I ratio was increased by CB. Results of the present study suggested that DEPs induced neuroinflammation, oxidative stress, and neurodegenerative-related tau overexpression and regulation by autophagy in IMR-32 cells. We demonstrated that DEPs are able to induce neurotoxicity, which could be associated with the development of neurodegenerative diseases.

Effects of deoxygedunin on Alzheimer-like pathologic dysfunction induced by D-galactose combined with AlCl3

To investigate the effects of Deoxygedunin on Aβ deposition, learning memory, and oxidative stress induced by D-galactose combined with AlCl3 in model rats with Alzheimer's disease and its possible mechanism. Male SD rats were randomly divided into three groups (n=12):control group, model group (AD) and intervention group (AD+Deo). Morris water maze test was used to detect learning/memory and cognitive function in rats.Glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) contents in homogenate of hippocampus were detected by enzyme-linked immunosorbent assay (ELISA).Tau protein expression in rat cerebral cortex was detected by immunohistochemistry.Western blot was used to detect the expressions of extracellular signal regulated kinase 1(ERK1), protein kinase B (PKB) and tropomyosin-related kinase B (TrkB) on TrkB signaling pathway. The results of water maze test showed that D-galactose combined with AlCl3 induced a significant increase in the escape latency compared with the control group (P<0.05).Deoxygedunin could reverse the increase of the escape latency of the model group (P<0.05).On the 7th day after removal of the platform, the model group showed an increase in escape latency compared with the control group and the intervention group (P<0.01), and the number of crossing platforms was declined (P<0.05); The results of immunohistochemistry and ELISA showed that the expressions of Aβ and tau protein in the model group were increased significantly compared with those of the control group (P<0.01).The activities of SOD and GSH-Px were decreased significantly and the content of MDA was increased significantly.Compared with the model group, Deoxygedunin could reverse the increase of the expressions of Aβ and tau protein (P<0.01), the decrease of SOD and GSH-Px activities (P<0.05) and the increase of the MDA content (P<0.05).Western blot results showed that Deoxygedunin treatment reversed the decreased phosphorylation levels of TrkB, AKT and ERK1 in hippocampus of the model group. Supplement of Deoxygedunin can significantly reverse Aβ deposition, oxidative stress and cognitive deficits by activating the TrkB signal transduction pathway, which suggest that Deoxygedunin may serve as a promising therapeutic candidate for attenuating AD-like pathological dysfunction induced by D-galactose combined with AlCl3.

Protective effects of genistein on Aβ₂₅₋₃₅-induced PC12 cell injury via regulating CaM-CaMKIV signaling pathway

Genistein is a kind of isoflavone compounds， also called phytoestrogens， with clinical effects on cardiovascular disease， cancer and postmenopausal-related gynecological diseases， and also has the potentiality in the prevention and treatment of Alzheimer's disease(AD). In this study， the protective effect of genistein on Aβ₂₅₋₃₅-induced PC12 cell injury and effect on CaM-CaMKIV signaling pathway were observed to investigate its mechanism for AD. PC12 cells were cultured in vitro and then the safe concentration of genistein and the modeling concentration and optimal time point of administration of Aβ₂₅₋₃₅ were screened by MTT assay. After being pretreated with different concentrations of genistein(25， 50， 100 μmol·L⁻¹) on PC12 cells， the AD model of PC12 cells was induced by Aβ₂₅₋₃₅. Then the survival rate of cells was detected by MTT assay; morphological change of cells was observed under the inverted microscope， and apoptosis of cells was assessed by AO/EB fluorescence staining; the neuroprotective effects of genistein on AD cell model were observed and the optimal concentration of genistein was determined. Expressions of mRNA and protein levels of CaM， CaMKK， CaMKIV and tau were detected by qRT-PCR and Western blot assay， respectively. The results showed that as compared with the blank group， the cell survival rate was decreased; the cell damage and apoptosis were increased; and the expressions of mRNA and protein levels of CaM， CaMKK， CaMKIV and tau were increased in AD model group. Genistein could significantly improve the cell survival rate， reduce the cell damage and apoptosis of AD cell model， and significantly down-regulate the expressions of mRNA and protein levels of CaM， CaMKK， CaMKIV and tau of AD cell model. These results indicated that genistein has obviously neuroprotective effect on the AD cell model induced by Aβ₂₅₋₃₅， and the mechanism may be related to the down-regulation of CaM-CaMKIV signaling pathway and Tau protein expression.

Atorvastatin and insulin equally mitigate brain pathology in diabetic rats

Although insulin and atorvastatin have been shown to exert glycemic control and could improve brain function, the effects of atorvastatin or insulin as well as the combination of atorvastatin plus insulin on brain pathology in diabetes mellitus type 1 (T1DM) are unclear. Therefore, this study investigated the effect of atorvastatin, insulin or combined drugs on brain pathology in streptozotocin-induced diabetic rats. Thirty-six male rats were divided into two groups, a control group (n = 12) and a diabetic or experimental group (n = 24). Diabetic rats were further divided into four groups (n = 6/group) and the groups received either a vehicle (normal saline), atorvastatin (10 mg/kg/day), insulin (4 U/day) or a combination of the drugs for 4 weeks. The control group rats were divided into two groups (n = 6/group) to receive either just the vehicle or atorvastatin for 4 weeks. We found that streptozotocin-induced diabetic rats developed hyperglycemia, showing evidence of increased brain oxidative stress, impaired brain mitochondrial function, increased brain apoptosis, increased tau protein expression, increased phosphorylation of tau protein expression and amyloid beta levels, and decreased dendritic spine density. Although atorvastatin and insulin therapies led to an equal reduction in plasma glucose level in these diabetic rats, the combined drug therapy showed the greatest efficacy in decreasing plasma glucose level. Interestingly, atorvastatin, insulin and the combined drugs equally mitigated brain pathology. Our findings indicate that the combined drug therapy showed the greatest efficacy in improving metabolic parameters. However, atorvastatin, insulin and the combined drug therapy shared a similar efficacy in preventing brain damage in T1DM rats.

ЕКСПРЕСІЯ TAU-БІЛКУ В СЕНСОМОТОРНІЙ КОРІ ПРИ МОДЕЛЮВАННІ ТРАНЗИТОРНОЇ ІШЕМІЇ ТА ІМУНОКОРЕКЦІЇ

Вступ. Ішемія головного мозку супроводжується дифузним пошкодженням структурних елементів нейронів. Одним із маркерів, який демонструє функціональні процеси в нервовій системі, є tau -білок.Мета дослідження – вивчити особливості експресії tau-білку в сенсомоторній корі за умов порушення кровопостачання та корекції нейродегенеративних змін імуномодуляцією.Матеріали і методи. При моделюванні транзиторної ішемії та корекції нейродегенеративних змін імунофаном, був проведений експеримент на 150 білих статевозрілих щурах-самцях масою 260–290 г. Були застосовані гістологічні, імуногістохімічний, морфометричний та статистичний методи дослідження.Результати. Проведені спостереження показали, що порушення кровообігу у корі мозку призводять до зростання експресії tau-білку в сенсомоторній корі. Виразність цих змін залежить від ступеню порушення кровообігу, що непрямим шляхом підтверджується наявністю змін експресії tau-білку в контрлатеральній півкулі.Стрімке наростання експресії tau-білку в гостру фазу після ішемічної атаки свідчить про дезорганізацію цитоскелету нервових волокон та, певною мірою, відображує явища аутонейротомії. Поява tau-білку в перикаріонах нейроцитів може бути показником тяжкості дегенеративних процесів. Виявлення tau-білку в тілах гліоцитів може бути розцінені як явища фагоцитозу продуктів розпаду.Застосування імунофану, який має певний нейропротекторний ефект, показало його здатність зменшувати індуковане ішемією підвищення експресії tau-білку. Це може бути пояснено як імунорегулюючими властивостями цього пептиду (аргініл-альфа-аспартил-лізил-валіл-тирозил-аргінін), так і його детоксикаційною дією, блокуванням вільнорадикальних процесів перекисного окиснення, запобіганням пошкодженню лімфоцитів та гранулоцитів, що приймають участь у нейрозапеленні .Висновки. Транзиторне порушення кровопостачання сенсомоторної кори великих півкуль призводить до зростання в ній експресії tau-білку, повного відновлення якої не відбувається навіть через 3 місяці після ішемічної атаки. Дисциркуляторні зміни у мозку, що виникають при мобілізації або перев’язуванні сонної артерії з боку операції, а також ті що виникають у контрлатеральній півкулі мозку, призводять до незначного, але на певному етапі, статистично значущому підвищені експресії tau-білку.Застосування імунофану при порушенні кровопостачання мозку призводить до менш виразного зростання експресії tau-білку в сенсомоторній корі.

Pathologic Thr175 tau phosphorylation in CTE and CTE with ALS.

ObjectiveTo investigate whether chronic traumatic encephalopathy (CTE) and CTE with amyotrophic lateral sclerosis (CTE-ALS) exhibit features previously observed in other tauopathies of pathologic phosphorylation of microtubule-associated protein tau at Thr175 (pThr175 tau) and Thr231 (pThr231 tau), and glycogen synthase kinase–3β (GSK3β) activation, and whether these pathologic features are a consequence of traumatic brain injury (TBI).MethodsTau isoform expression was assayed by western blot in 6 stage III CTE cases. We also used immunohistochemistry to analyze 5 cases each of CTE, CTE-ALS, and 5 controls for expression of activated GSK3β, pThr175 tau, pThr231 tau, and oligomerized tau within spinal cord tissue and hippocampus. Using a rat model of moderate TBI, we assessed tau pathology and phospho-GSK3β expression at 3 months postinjury.ResultsCTE and CTE-ALS are characterized by the presence of all 6 tau isoforms in both soluble and insoluble tau isolates. Activated GSK3β, pThr175 tau, pThr231 tau, and oligomerized tau protein expression was observed in hippocampal neurons and spinal motor neurons. We observed tau neuronal pathology (fibrillar inclusions and axonal damage) and increased levels of pThr175 tau and activated GSK3β in moderate TBI rats.ConclusionsPathologic phosphorylation of tau at Thr175 and Thr231 and activation of GSK3β are features of the tauopathy of CTE and CTE-ALS. These features can be replicated in an animal model of moderate TBI.

Thyroid Hormone Enhances Neurite Outgrowth in Neuroscreen 1 Cells.

Objectives:Alzheimer’s disease (AD) is a neurodegenerative disorder that affects millions of individuals. Moreover, hypothyroidism has been identified as one of the risk factors that may contribute to the development of AD. Here, we investigated whether there was a correlation among expression levels of proteins involved in the formation of AD lesions, neurite outgrowth, and thyroid hormone levels.Methods:Cells were grown in media supplemented with different levels of 3,5,3’-triiodothyronine (T3) and then processed for neurite outgrowth and to prepare RNA samples. RNA samples were analysed using quantitative real-time PCR. Protein levels were measured using in cell-Western blotting analysis.Results:By using neurite outgrowth studies, it was demonstrated that T3 treatment enhanced neurite outgrowth in NS-1 cells in a time- and dose-dependent manner. Quantitative real-time PCR studies further confirmed that NS-1 cells expressed substantial levels of TRα and significantly less TRβ, either of which could be responsible for the T3-dependent effects on neurite outgrowth. Although the overall tau protein expression was not affected in response to T3 treatment, the splicing of tau exon 10 was impacted in the direction of producing more tau molecules that excluded the exon (tau 3R).Conclusion:The results of this study are critical not only to understand the probable link between hypothyroidism and AD but also in providing the basis for future prevention and treatment of AD in hypothyroid patients.

Co-occurrence of mixed proteinopathies in late-stage Huntington's disease.

Accumulating evidence highlights the potential role of mixed proteinopathies (i.e., abnormal protein aggregation) in the development of clinical manifestations of neurodegenerative diseases (NDD). Huntington's disease (HD) is an inherited NDD caused by autosomal-dominant expanded CAG trinucleotide repeat mutation in the gene coding for Huntingtin (Htt). Previous studies have suggested the coexistence of phosphorylated-Tau, α-synuclein (α-Syn) and TAR DNA-binding protein 43 (TDP-43) inclusions in HD. However, definite evidence that HD pathology in humans can be accompanied by other proteinopathies is still lacking. Using human post-mortem putamen samples from 31 controls and 56 HD individuals, we performed biochemical analyses of the expression, oligomerization and aggregation of Tau, α-Syn, TDP-43, and Amyloid precursor protein (APP)/Aβ. In HD brain, we observed reduced soluble protein (but not mRNA) levels of Htt, α-Syn, and Tau. Our results also support abnormal phosphorylation of Tau in more advanced stages of disease. Aberrant splicing of Tau exons 2, 3 (exclusion) and 10 (inclusion) was also detected in HD patients, leading to higher 0N4R and lower 1N3R isoforms. Finally, following formic acid extraction, we observed increased aggregation of TDP-43, α-Syn, and phosphorylated-Tau during HD progression. Notably, we observed that 88% of HD patients with Vonsattel grade 4 neuropathology displayed at least one non-Htt proteinopathy compared to 29% in controls. Interestingly, α-Syn aggregation correlated with Htt, TDP-43 and phosphorylated-Tau in HD but not in controls. The impact of this work is twofold: (1) it provides compelling evidences that Tau, α-Syn and TDP-43 proteinopathies are increased in HD, and (2) it suggests the involvement of common mechanisms leading to abnormal accumulation of aggregation-prone proteins in NDD. Further studies will be needed to decipher the impact of these proteinopathies on clinical manifestation of HD.

Tau accumulation in the retina promotes early neuronal dysfunction and precedes brain pathology in a mouse model of Alzheimer\u2019s disease

BackgroundTau is an axon-enriched protein that binds to and stabilizes microtubules, and hence plays a crucial role in neuronal function. In Alzheimer’s disease (AD), pathological tau accumulation correlates with cognitive decline. Substantial visual deficits are found in individuals affected by AD including a preferential loss of retinal ganglion cells (RGCs), the neurons that convey visual information from the retina to the brain. At present, however, the mechanisms that underlie vision changes in these patients are poorly understood. Here, we asked whether tau plays a role in early retinal pathology and neuronal dysfunction in AD.MethodsAlterations in tau protein and gene expression, phosphorylation, and localization were investigated by western blots, qPCR, and immunohistochemistry in the retina and visual pathways of triple transgenic mice (3xTg) harboring mutations in the genes encoding presenilin 1 (PS1M146 V), amyloid precursor protein (APPSwe), and tau (MAPTP301L). Anterograde axonal transport was assessed by intraocular injection of the cholera toxin beta subunit followed by quantification of tracer accumulation in the contralateral superior colliculus. RGC survival was analyzed on whole-mounted retinas using cell-specific markers. Reduction of tau expression was achieved following intravitreal injection of targeted siRNA.ResultsOur data demonstrate an age-related increase in endogenous retinal tau characterized by epitope-specific hypo- and hyper-phosphorylation in 3xTg mice. Retinal tau accumulation was observed as early as three months of age, prior to the reported onset of behavioral deficits, and preceded tau aggregation in the brain. Intriguingly, tau build up occurred in RGC soma and dendrites, while tau in RGC axons in the optic nerve was depleted. Tau phosphorylation changes and missorting correlated with substantial defects in anterograde axonal transport that preceded RGC death. Importantly, targeted siRNA-mediated knockdown of endogenous tau improved anterograde transport along RGC axons.ConclusionsOur study reveals profound tau pathology in the visual system leading to early retinal neuron damage in a mouse model of AD. Importantly, we show that tau accumulation promotes anterograde axonal transport impairment in vivo, and identify this response as an early feature of neuronal dysfunction that precedes cell death in the AD retina. These findings provide the first proof-of-concept that a global strategy to reduce tau accumulation is beneficial to improve axonal transport and mitigate functional deficits in AD and tauopathies.

Lead exposure and tau hyperphosphorylation: An in vitro study

The presence of fibrillary lesions, which are mainly composed of the microtubule associated protein tau (MAPT) in neurons, has gained immense recognition due to their presence in numerous neurodegenerative diseases, including Alzheimer's disease (AD). Dysregulation of tau is related with its altered site-specific phosphorylation which is followed by tau polymerization, neuronal dysfunction and death. Previous reports by us suggest that molecular alterations favor abundant tau phosphorylation and immunoreactivity in the frontal cortex of aged primates and rodents with past exposure to lead (Pb). Here we report the involvement of Pb-induced alterations in tau and hyperphosphorylation of tau in differentiated Human Neuroblastoma SH-SY5Y cells exposed to a series of Pb concentrations (5–100μM) for 48h. These cells were analyzed for the protein expression of total tau, site-specific tau hyperphosphorylation, cyclin dependent kinase 5 (CDK5) and p35/p25 at selected time points (24–144h), after Pb exposure had ceased. Western blot analysis revealed aberrant tau levels as well as site-specific tau hyperphosphorylation accompanied by elevated CDK5 levels and altered protein ratio of p35/p25 particularly at 72 and 144h. These changes provide additional evidence that neurodegenerative events are subject to environmental influences.