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.

Peripheral insulin resistance aggravated cognitive impairment and phosphorylated Tau protein in MAPT transgenic mice / 中华行为医学与脑科学杂志

Objective:To investigate the effects of insulin resistance induced by long-term high-fat diet on cognitive function and brain phosphorylated Tau protein in pR5 MAPT Tau transgenic mice.Methods:Eight-week-old female pR5 MAPT transgenic mice were divided into standard diet(STD) group (pR5 STD, n=8) and high-fat diet(HFD) group (pR5 HFD, n=8). Female wild-type C57BL/6 mice fed with STD were used as control group (WT STD, n=8). The experiment was carried out for 30 weeks until the mice were old.During the experiment, the weight of mice was measured once a week and fasting blood glucose was measured once every two weeks.Thirty weeks later, glucose tolerance test and insulin tolerance test were carried out.Forced swimming test and tail suspension test were used to evaluate the depressive behavior of mice, and elevated plus maze test was used to evaluate the anxiety behavior, Morris water maze test was used to evaluate spatial memory behavior.The levels of total Tau protein and phosphorylated Tau proteins H7-tau, p-tau-Ser396 and p-tau-Thr231 were detected by Western blot.SPSS 17.0 software was used for statistical analysis, repeated measurement ANOVA was used for the data of glucose tolerance test and insulin tolerance test, one-way ANOVA was used for multi group comparison, and LSD test was used for further pairwise comparison. Results:After 30 weeks of high-fat diet, there were significant differences in body weight and fasting blood glucose among the three groups ( F=808.31, 1 117.18, both P<0.01). The body weight of mice in pR5 HFD group ((54.35±2.52)g) was higher than those in pR5 STD group ((24.95±1.15) g) and WT STD group ((23.86±1.10) g) (both P<0.01), and the fasting blood glucose of mice in pR5 HFD group ((8.12±0.24) mmol/L) was significantly higher than those in pR5 STD group ((4.64±0.13) mmol/L) and WT STD group ((4.45±0.22) mmol/L) (both P<0.01). Glucose tolerance test showed that within 120 minutes after injection of glucose, there was a significant time and group interaction in the blood glucose value among the three groups ( F=113.30, P<0.01). After glucose injection, the peak value of blood glucose in pR5 HFD group was delayed, suggesting that glucose tolerance in pR5 HFD group was impaired.The insulin tolerance test showed that there was a significant interaction between time and group in the insulin tolerance among the three groups ( F=209.92, P<0.01). After injection of insulin, the blood glucose in pR5 HFD group decreased slowly, reaching the valley value at 60 min, and then the blood glucose increased significantly, suggesting that the sensitivity of pR5 HFD group mice to insulin decreased significantly.There were significant differences in the percentage of forced swimming immobility time and tail suspension immobility time among the three groups ( F=37.05, 59.29, both P<0.01). The two indexes of pR5 STD group and pR5 HFD group were both higher than those of WT STD group (all P<0.01), and those of pR5 HFD group were both higher than those of pR5 STD group (both P<0.01). The results of elevated plus maze showed that there were significant differences in the activity distance and time in open arm among the three groups ( F=7.82, 10.37, both P<0.05) .The activity distance ((0.40±0.21) m) and activity time ((27.38±8.80) s) of pR5 HFD group were significantly lower than those of pR5 STD group ((2.31±1.74) m, (63.56±27.52)s) (both P<0.05). The space exploration test showed that the residence time in the target quadrant of pR5 HFD group ((15.56±1.16)s) was less than that of pR5 STD group((19.18±0.64)s)( P<0.01), and the time of entering the platform area of pR5 HFD group((1.43±0.06)s) was less than that of pR5 STD group((1.66±0.12)s)( P<0.01). Western blot showed that there were significant differences in the levels of total Tau protein, H7-tau, p-tau-Ser396 and p-tau-Thr231 protein among the three groups ( F=101.50, 80.60, 55.47, 30.89, all P<0.05). Further pairwise comparison showed that the levels of the four Tau proteins showed: the levels of the proteins in pR5 STD group and pR5 HFD group were all higher than those of WT STD group (all P<0.01), and those in pR5 HFD group were all higher than those in pR5 STD group (all P<0.05). Conclusion:Long-term high fat diet causes obesity, hyperglycemia and peripheral insulin resistance, and promotes the cognitive impairment of MAPT mice, which is related to the increase of Tau protein phosphorylation in the brains of MAPT mice.

Research on flash visual evoked potential and dynamic changes of Tau and its phosphorylation in rat model of traumatic optic neuropathy / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To detect the visual dysfunction, and investigate the changes of Tau and its phosphorylated Ser396/Ser404 forms in retinas and optic nerves in traumatic optic neuropathy(TON)model rats by using FVEP technique.<p>METHODS: Totally 30 SD rats were conducted FVEP electrode implantation. One week later, all rates were implemented TON operation with the optic nerve of left eye crushed and the optic nerve of right eye exposed(sham-operated). FVEP detections were performed respectively in these TON model rats at 1, 3, 7, 14, and 28d post crush, with 5 rats tested at each time point. After FVEP tests were taken, rats were sacrificed and then retinas and optic nerves of left eyes were separated for detecting the expression levels of Tau and pTau-Ser396/404 by Western Blot.<p>RESULTS: Typical FVEP waves were observed in the sham-operated eyes. Compared to the sham group, the N2 waves were significantly delayed and the amplitude of N2-P2 were greatly reduced at each time point in the operation eyes. However, the differences of N2 wave and the amplitude reduction of N2-P2 were not significant at each time point after crush. The contents of total Tau protein in retinas of TON rats sharply decreased at 1d post crush, briefly recovered at 7d post crush, and remained a slightly lower level than normal condition till 28d. The changes of pTau-Ser396/404 were consistent with the changes of total Tau in retains and the Ser396 was the main phosphorylation site. However, the total Tau contents in optic nerves of TON rats increased gradually, and peaked at the 14d post crush and remained till 28d. The changes of pTau-Ser396/404 were similar to the changes of total Tau in optic nerves, which peaked at 7d post crush. However, Ser404 was the main phosphorylation site of Tau in optic nerves.<p>CONCLUSION: The related indexes of N2 and P2 waves in FVEP can be used to detect the visual dysfunction in TON rats. After TON, the content changes of total Tau in retinas and optic nerves were much different while the changes of pTau-Ser396/404 followed the alterations of total Tau in the two locations. However, the main phosphorylation site of Tau was differnet according to the locations.

Serum amyloid A 3 deficiency improves cognitive impairment and attenuates tau pathology in mouse model of Alzheimer′s disease / 中国药科大学学报

@#To explore the effects of serum amyloid A (SAA) on the cognitive function and tau phosphorylation in Alzheimer''s disease (AD), two mouse models of AD were constructed: one is the APP/PS1 double transgenic mice mated with the Saa3 knockout (Saa3-/-) mice, and the other involves intracerebroventricular (ICV) injection of streptozotocin (STZ) into WT and Saa3-/- mice.The expression of Saa3 in mouse brain was evaluated using immunofluorescence staining.The body weight of STZ injection mice during modeling was measured.The motor coordination and balance, spontaneous exploratory activity, and anxiety level of these mice were assessed by Rotarod test, open field, and elevated plus maze, respectively.Spatial reference learning and memory were evaluated by Morris water maze.Western blot was used to detect the phosphorylation level of tau protein in mouse brain tissue.The results showed that the expression of Saa3 was increased in the brain of AD mice.The Saa3 gene deletion had no significant effect on motor coordination, balance and spontaneous exploratory activity in these mice, yet with alleviated anxiety level of AD model mice.Saa3 deficiency improved the impairment of learning and memory function of intracerebroventricular STZ injection mice and APP/PS1 mice. Deletion of Saa3 relieved the hyperphosphorylation of tau protein at specific sites in the brain of AD mice. The difference between the groups was statistically significant (P < 0.05). These results suggest that Saa3 is associated with cognitive function and tau pathology in AD, and that the inhibition of SAA may be a new strategy for the treatment of AD.

Effects of Electroacupuncture on Learning-memory and P35/P25-Cyclin-dependent Kinase 5-Tau Phosphorylation Signal Pathway in Prefrontal Cortex of Rats with Alzheimer's Disease / 中国康复理论与实践

Objective:To observe the effect of electroacupuncture at Baihui (DU20) and Shenshu (BL23) acupoints on learning-memory ability and expression of the relative protein of P35/P25-cyclin-dependent kinase 5 (CDK5)-Tau phosphorylation signaling pathway in the prefrontal cortex (PFC) in rats with Alzheimer's disease (AD), so as to reveal its potential mechanisms in treating AD. Methods:Male adult Sprague-Dawley rats were randomly divided into normal control group, sham group, model group and treatment group with six rats in each group. The AD model was constructed by bilateral hippocampal injection of Aβ25-35 in latter two groups. Equal amount of normal saline was injected into the sham group. The treatment group was acupunctured at Baihui and Shenshu once a day for ten days. All the rats were tested with Morris Water Maze. Immunohistochemistry staining and Western blotting were used to detect the related protein of P35/P25-CDK5-Tau protein phosphorylation in the PFC. Results:Compared with the normal control group and the sham group, the escape latency and escape length increased (P < 0.05) and the times crossing the platform reduced (P < 0.05) in the model group; compared with the model group, the escape latency and escape length reduced (P < 0.05), and the times crossing the platform increased (P < 0.05) in the treatment group. The optical density of P35/P25 and CDK5 were significantly higher in the model group than in the normal control group and the sham group (P < 0.01), and they were lower in the treatment group than in the model group (P < 0.001). The relative expression of P35/P25, CDK5, Tau[pS199] and Tau[pS202] were higher in the model group than in the normal control group and the sham group (P < 0.05), and the expression of the above proteins was lower in the treatment group than in the model group (P < 0.05). Conclusion:Electroacupuncture could improve the learning-memory and spatial exploration ability, which associate with inhabiting the P35/P25-CDK5-Tau protein phosphorylation signaling pathway in the PFC to delay the development of AD.

Shenqi Xingnao Granules ameliorates cognitive impairments and Alzheimer's disease-like pathologies in APP/PS1 mouse model / 中草药·英文版

Objective: Alzheimer's disease (AD) is along with cognitive decline due to amyloid-β (Aβ) plaques, tau hyperphosphorylation, and neuron loss. Shenqi Xingnao Granules (SQXN), a traditional Chinese medicine, significantly ameliorated the cognitive function and daily living abilities of patients with AD. However, till date, no study has investigated the mechanism of action of SQXN on AD. The present study aimed to verify the effects of SQXN treatment on cognitive impairments and AD-like pathologies in APP/PS1 mice. Methods: Four-month-old APP/PS1 transgenic (Tg) mice were randomly divided into a model group and SQXN-treated (3.5, 7, 14 g/kg per day) groups. Learning-memory abilities were determined by Morris water maze and object recognition test. All mice were sacrificed and the brain samples were collected after 75 d. The soluble Aβ contents were detected by Elisa kit; The levels of expression of NeuN, APP, phosphorylated tau and related protein were measured by Western blotting; The inflammation factors were detected by the proinflammatory panel kit. Results: Four-month-old APP/PS1 mice were administered SQXN by oral gavage for 2.5 months. Using the Morris water maze tests and Novel object recognition, we found that SQXN restored behavioral deficits in the experimental group of Tg mice when compared with the controls. SQXN also inhibited neuronal loss (NeuN marker). SQXN treatment decreased soluble Aβ42 through inhibiting the expression of sAPPβ and BACE-1 without regulating full-length amyloid precursor protein (FL APP). Insulin degrading enzyme (IDE), the Aβ degrading enzyme, were increased by SQXN. In addition, SQXN reduced hyperphosphorylated tau protein levels and prevented excessive activation of p-GSK-3β in the brain of APP/PS1 mice. Compared with APP/PS1 transgenic negative mice, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-12p70, KC/GRO and TNF-α were not obviously changed in the brain of 6.5-month-old APP/PS1 transgenic (Tg) mice. However, SQXN could inhibited the expression of IL-2. Conclusion: These results demonstrate that SQXN ameliorates the cognitive impairments in APP/PS1 mice. The possible mechanisms involve its inhibition of neuronal loss, soluble Aβ deposition, tau hyperphosphorylation and inflammation.

Banqiao Codonopisis Pilosula improves cognitive dysfunction in AD model rats by PP2A signaling pathway / 中国药理学通报

Aim To investigate the protective effect of Banqiao Codonopsis pilosula (BCP) on cognitive function in rats with Alzheimer's disease(AD) induced by Okadaic acid (OA) and its possible mechanism. Methods SD rats were randomly divided into DMSO group, OA group and BCP low, medium, high treatment group. The rats were gavage administered in groups of one week and two weeks. The water maze training was continued for five days before modeling, and modeling was started 24 hours after the training. The bilateral hippocampus of DMSO group was injected with 10% DMSO 1.5 |xL. OA group and BCP treatment group were injected with OA (0. 392 mmol • L"1) 1.5 (iL. The water maze test was used to observe the spatial learning ability of rats. Western blot was used to observe the activity of PP2A, the phosphoryla-tion of Tau protein and the expression of synaptic protein in hippocampus, and the Nissl's staining to observe the changes of Nissl bodies in hippocampus CA1 and CA3. Results Water maze experiments showed that BCP could improve spatial memory impairment in AD rats. Western blot results showed that BCP in-creased PP2A activity, increased synaptic protein expression, and decreased Tau protein phosphorylation. Nissl's staining suggested an increase in the number of Nissl bodies in BCP treatment group. Conclusions BCP can up-regulate PP2A activity, decrease the phosphorylation level of Tau protein, increase the expression of synaptic proteins, and repair damaged neurons.

Trillium tschonoskii Maxim improves cognitive dysfunction in Alzheimer’s disease induced by okadaic acid in rats and its possible mechanism / 中国药理学通报

Aim To assess the effects of Trillium Tschonoskii Maxim ( TTM) decoction on learning and memory dysfunction in Alzheimer’ s disease ( AD ) model rats which induced by okadaic acid( OA) and its possible mechanism. Methods The SD rats were di-vided into ten groups,namely,d DMSO control group, OA group, TTM high-dose ( 0. 5 g·kg-1·d-1) group,TTM medium-dose ( 1 g·kg-1·d-1) group, TTM lower-dose (2 g·kg-1·d-1) group,and these groups were divided into one week and two weeks of gavage. Treatment groups were gavaged with TTM de-coction twice a day. After 5 days of Morris water maze training,treatment groups and AD model groups were injected with OA (0.392 mmol·L-1,1. 5 μL) in bi-lateral hippocampal of the rats. The DMSO groups were injected with 10% DMSO. The spatial memory reten- tion wereas detected by water maze at 24 h after injec-tion. After the test, we prepared sample for Western blot and Nissl’s staining. The Western blotting test was used to detect the PP2A activity and the phospho-rylation of Tau protein in the hippocampus. Nissl’'s staining was used to observe the changes of the number of Nissl’s bodies in the hippocampal CA1 and CA3 re-gions. Results The Morris water maze test showed that after injection of OA, the latency of TTM groups wereas shorter than that of OA groups. Western blot showed that the high dose TTM could increase the ac-tivity of PP2A and decrease the level of Tau phospho-rylation at PS-Tau396,,PT-Tau404. The Nissl’s stai-ning results showed that the number of Nissl’s bodies in the hippocampal CA1 and CA3 regions of OA groups wereas significantly attenuated compared with that of the number of Nissl's bodies in the hippocampal CA1 and CA3 regions than DMSO groups. The number of Nissl’s bodies in high groups were morewas larger than that of OA group. Conclusion The results show that TTM can improve the learning and memory dysfunction in AD model rats which induced by OA. The mecha- nism wasis probably that TTM can increase PP2A ac-tivity and then down-regulate the level of Tau phospho-rylation and improve neural development.

Trillium Tschonoskii Maxim improves cognitive dysfunction in AD rats by inhibiting GSK-3βactivity, attenuating tau pathologies and promoting synaptic development / 中国药理学通报

Aim To assess the effects of Trillium Tschonoskii Maxim ( TTM ) decoction on Tau protein phosphorylation and synaptic development in AD model rats induced by high activity GSK-3β. Methods The SD rats were divided into five groups of ten animals, named sham-operated group ( blank group) , AD model group, TTM group (0. 5, 0. 25, 0. 125 g·kg-1 · d-1 ) . Treatment group received gavage once a day for seven days with TTM decoction, while other groups by gavage once a day for seven days with drinking water. On 2nd day by gavage, Morris water maze test was used to assess the spatial learning and memory ability of the rats. After five days' training, rats in the treat-ment groups and AD model group were injected wort-mannin ( WT, PI3K specific inhibitor ) and GF-109203X (GFX, PKC specific inhibitor) (100 μmol ·L-1 of each, total volume of 10 μL) into the right lateral ventricle. Western blot was used to detect the levels of phosphorylation Tau protein at multiple sites and the expression level of PI3K, Akt, PKC, GSK-3β(S9, T216) and synapse-associated proteins. Immu-nohistochemical method was used to detect the hyper-phosphorylation of Tau protein in hippocampus of rats. Golgi staining was applied to detect the number and morphological changes of synaptic development and dendritic spines. Nissl' s staining was employed to ob-serve the development of neonatal neurons in hippo-campus and cortex. Results Western blot showed that the phosphorylation level of Tau in hippocampus increased in model group, and the activity of GSK-3βwas up-regulated. Among them, however, in middle dose TTM group, the phosphorylation level of Tau in hippocampus decreased and the activity of GSK-3βde-creased. The expression levels of p-PKC and p-Akt in low and middle dose treatment group were higher than those in model group, thus increasing the activity of PKC and Akt to inhibit the activity of GSK-3β kinase. Immunohistochemistry also indicated that TTM could decrease the biological effects of Tau phosphorylation in hippocampus of AD rats. Western blot showed that TTM could increase the expression levels of synapsin-1 , syn-aptophysin and GluR-1 in hippocampus of AD rats. Nissl staining showed that the number of Nissl bodies in hippocampal neurons of AD model group were signif-icantly fewer than those of sham operation group, which could be increased by TTM middle and high dose group, and the complexity and dendritic spine density of hippocampal neurons in AD rats could be en-hanced as well. Conclusion TTM can effectively im-prove the cognitive function of AD rats induced by the increase of GSK-3β activity, and its possible mecha-nism may be via down-regulating the activity of GSK-3β and inhibiting the phosphorylation of tau protein and promoting the development of neurons.

Long-term Helicobacter pylori Infection Does Not Induce Tauopathy and Memory Impairment in SD Rats / 华中科技大学学报（医学）（英德文版）

Helicobacter pylori (H.pylori) infection is a recognized risk factor of dementia,while its role and mechanism in Alzheimer disease (AD) remained unclarified.Our previous study has identified that injection of soluble H.pylori filtrate could induce AD-like pathologic changes and cognitive impairment in SD rats.In the present study,we further explored the effect of long-term stomach colonization of H.pylori bacteria on the brains of SD rats.The results showed that H.pylori bacteria gavage induced an efficient colonization of H.pylori in the stomach after four weeks.However,there was no significant change of tau phosphorylation at Thr205 (pT205),Thr231 (pT231),Ser396 (pS396) and Ser404 (pS404) sites in the hippocampus and cerebral cortex.The H.pylori-infected rats also showed no cognitive impairment.These observations may result from inefficient release of bacterial pathogenic factors or the overall lack of host inflammatory responses.We conclude that SD rat with long-term H.pylori colonization in the stomach is not a suitable animal model for exploring the effects of H.pylori infection on brain function in human beings;administration of bacterial filtrates may better reveal the systemic pathologic changes induced by bacterial infection in animals which show a negative host response to bacterial colonization.

Protective effect of fibroin peptides on Aβ25-35-induced injury in SH-SY5Y cells and its mechanism / 中国药科大学学报

This study aimed at exploring the molecular mechanism of fibroin peptide in preventing the Aβ25-35-induced neuronal damages in SH-SY5Y cells.MTT was used to detect the effect of fibroin peptide on the changes of the Aβ25-35-induced injuries in SH-SY5Y cells;Western blot was employed to detect the effect of fibroin peptide on the changes of the Aβ25-35-induced hyperphosphorylation of Tau in SH-SY5Y cells;DCFH-DA probe method was used to detect the effect of fibroin peptide on the Aβ-induced production of intracellular reactive oxygen species (ROS) in SH-SY5Y cells.The results indicated that fibroin peptide could improve the activity of the PP2A and inhibit the activity of GSK-3β to decrease the hyperphosphorylation of Tau induced by Aβ25-35.Fibroin peptide could significantly prevent the Aβ25-35-induced neuronal damages and multisite Tau hyperphosphorylation.In addition,fibroin peptide could also reduce oxidative damage to protect neurons by significantly decreasing the Aβ25-35-induced production of intracellular ROS.

Banqiao Codonopisis Pilosula improves cognitivedysfunction induced by high GSK-3β activity and its possible mechanism / 中国药理学通报

Aim To assess the effects of Banqiao Codonopisis Pilosula(BCP)decoction on learning and memory dysfunction in AD model rats induced by high activity GSK-3β and its possible mechanism.Methods The SD rats(4 months old,♂)were divided into five groups,namely,sham-operated group(blank group),AD model group,BCP high-dose(2.16 g·kg-1·d-1)group,BCP medium-dose(1.08 g·kg-1·d-1)group,and BCP lower-dose(0.54 g·kg-1·d-1)group.Treatment group received BCP decoction by gavage once a day for 14 days,while other groups were offered drinking water by gavage once a day for 14 days.The autonomous behavior activities of all rats were observed and recorded after gavage.In the last seven days by gavage,Morris water maze test was used to test the spatial learning and memory ability of the five groups.After five days training,treatment groups and AD model group were injected wortmannin(WT,PI3K specific inhibitor)and GF-109203X(GFX,PKC specific inhibitor)(100 μmol·L-1 of each,total volume of 10 μL)into the right lateral ventricle of the rats.The blank group was only injected 2％DMSO.The spatial memory retention was detected by water maze 24 hours after lateral ventricle injection.Then,changes in the spatial learning memory of rats were observed.The level of Tau phosphorylation in SD rat hippocampus and the expression and activity changes of related protein kinase GSK-3β were detected by Western blot and immunohistochemistry.The changes of Nissl bodies in SD rat hippocampus were observed by Nissl′s staining.Results After intragastric administration of BCP,the rat autonomous behavior activities in each group all showed a declining trend,and the differences in low-dose and middle-dose groups had statistical significance compared with blank group.The Morris water maze tests showed that the latency navigation of model group was significantly longer than that of blank group(P<0.01),while that of the BCP three doses groups was shorter than that of model group(P<0.05).Compared with the same group,the latency navigation of the three groups after gavage BCP low,middle and high dose was significant shorter than that without gavage(P<0.05).Western blot results showed that the activity of GSK-3β in AD model group was up-regulated compared with the blank group.However,BCP inhibited activity of GSK-3β.Western blot and immunohistochemistry results showed the level of Tau phosphorylation in AD model group was increased compared with the blank group in the area of CA3(P<0.05).Compared with AD model group,the level of Tau phosphorylation was decreased in treatment group.Nissl′s staining results showed that dendritic spines in AD model group was significantly attenuated compared with the blank group(P<0.05).Far more dendritic spines were observed in treatment group than in AD model group.The number of Nissl′s bodies in neuron cells of hippocampus in hippocampal CA3 was obviously larger in treatment groups than in AD model group.These effect of BCP was dose-dependent.Conclusions BCP can prevent the learning and memory dysfunction in AD model rats induced by high activity of GSK-3β.The mechanism may be related to inhibiting GSK-3β activity and then reducing the level of phosphorylation of Tau and improving neural development.

Effect of Puerarin on Tau Hyperphosphorylation in the Olfactory Bulb of Alzheimer's Disease Rat Brain / 医药导报

Objective To observe the effect of Puerarin on the level of tau phosphorylation in the olfactory bulb of Alzheimer's disease rat brain, and explore the underlying molecular mechanism.Methods ① Twenty-two male SD rats were randomly divided into the normal control group, model control group and Puerain-treated group.The levels of tau-1, PS396 and tau-5 in the olfactory bulb were detected by Western blotting.② Twenty male SD rats were randomly divided into model control group, low-dose Puerarin (40 mg·kg-1·d-1), medium-dose puerarin (80 mg·kg-1·d-1) and high-dose puerarin (160 mg·kg-1·d-1) groups.The levels of tau-1 and PS396 phosphorylation in the olfactory bulb were detected by Western blotting.③ The level of GSK-3β phosphorylation in the olfactory bulb of the normal control group, model control group A and puerain-treated group was detected by Western blotting.Results ① It was shown by Western blotting that the relative expression of tau-1 was significantly decreased in the olfactory bulb of the model group A(0.49±0.07)rat brain compared with the normal control group(0.85±0.03)(P<0.01), and the level of tau-1 was obviously higher in the puerarin-treated group(0.58±0.03)compared with that of the model group A(P<0.05).The differences of the levels of tau-5 and PS396 in the olfactory bulb were insignificant among the 3 groups.②Compared with the model group B, the expression of tau-1 in the olfactory bulb was significantly enhanced in the low-, medium-and high-dose of puerarin group: (0.39±0.09)vs(0.69±0.11),(0.55±0.11),(0.70±0.04);and the level of PS396 was significantly decreased in the olfactory bulb of low-dose puerarin group(0.36±0.07) compared with the model group B(0.55±0.05)(P<0.01).③Compared with the normal control group(0.96±0.07), the ratio of pS9-GSK-3β/tGSK-3β was obviously decreased in the olfactory bulb of the model group A(0.51±0.12),while that was significantly increased in the puerarin group(0.62±0.03) compared with the model group A(P<0.01).Conclusion Puerarin can attenuate AD-like tau hyperphosphorylation in the olfactory bulb of Alzheimer's disease rat brains, and decreased activity of GSK-3β might be involved in the effects of puerarin on tau hyperphosphorylation.

Icariin protects SH-SY5Y cells from formaldehyde-induced injury through suppression of Tau phosphorylation / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the neuroprotective effects of icariin on formaldehyde (FA)-treated human neuroblastoma SH-SY5Y cells and the possible mechanisms involved.</p><p><b>METHODS</b>SH-SY5Y cells were divided into FA treatment group, FA treatment group with icariin, and the control group. Cell viability, apoptosis, and morphological changes were determined by cell counting kit-8 (CCK 8), flow cytometry, and confocal microscopy, respectively. The phosphorylation of Tau protein was examined by western blotting.</p><p><b>RESULTS</b>FA showed a half lethal dose (LD50) of 0.3 mmol/L in SH-SY5Y cells under the experimental conditions. Icariin (1-10 µmol/L) prevented FA-induced cell death in SH-SY5Y cells in a dose-dependent manner, with the optimal effect observed at 5 µmol/L. After FA treatment, the absorbance in FA group was 1.31±0.05, while in the group of icariin (5 µmol/L) was 1.63±0.05. Examination of cell morphology by confocal microscopy demonstrated that 5 µmol/L icariin significantly attenuated FA-induced cell injury (P <0.05). Additionally, Icariin inhibited FA-induced cell apoptosis in SH-SY5Y cells. Results from western blotting showed that icariin suppressed FA-induced phosphorylation at Thr 181 and Ser 396 of Tau protein, while having no effect on the expression of the total Tau protein level. Furthermore, FA activated Tau kinase glycogen synthase kinase 3 beta (GSK-3β) by enhancement of Y216 phosphorylation, but icariin reduced Y216 phosphorylation and increased Ser 9 phosphorylation.</p><p><b>CONCLUSION</b>Icariin protects SH-SY5Y cells from FA-induced injury poßsibly through the inhibition of GSK-3β-mediated Tau phosphorylation.</p>

lnhibiton of JNK phosphorylation involved in melatonin′s protection of calyculin A-induced tau hyperphosphorylation / 中国药理学与毒理学杂志

OBJECTlVE To explore the mechanisms of tau hyperphosphorylation induced by calyculin A ( CA) in neuroblastoma cells and the effect of melatonin. METHODS N2a cells were treated with CA 5 nmol·L-1 , or CA with melatonin 50 μmol·L-1 , or CA with vitamin E ( Vit E ) 50 μmol·L-1 for 12 h. The level of tau phosphorylation at Ser422 ( recognized by R145d antibody) site and the level of phosphorylated c-Jun N-terminal kinases ( p-JNK ) and phosphorylated mitogen-activated protein kinase kinase 4 ( p-MKK4 ) were detected with immunoblotting, the level of malondialdehyde ( MDA ) was assayed with fluorimetry, and the activity of p38-mitogen activated protein kinase ( p38MAPK ) was assayed by radioimmunobloting. RESULTS CA treatment increased the level of phosphorylated tau at Ser422 site (1.70±0.19, 1.0, P<0.01), and melatonin attenuated the effect of CA (0.98±0.12, 1.70± 0.19, P<0.01). ln addition, CA treatment increased the level of MDA (μmol·g-1 protein:0.241±0.006, 0.141±0.006, P<0.01) and melatonin antagonized the increase of MDA induced by CA (μmol·g-1 protein:0.172±0.004, 0.193±0.005, 0.241±0.006, P<0.01) . CA treatment increased the level of p-JNK (1.91±0.27, 1, P<0.01) and p-MKK4 (1.81±0.09, 1, P<0.01) and melatonin antagonized the effect of CA induced increase of p-JNK (1.11±0.15, 1.91±0.27, P<0.01) and p-MKK4 (1.14±0.06, 1.81±0.09, P<0.01) without changing the level or activity of p38MAPK. Both JNK inhibitor ( SP600125 ) and MKK4/JNK transduction pathway inhibitor antagonized CA induced tau phosphorylation at Ser422 site and JNK phosphorylation. CONCLUSlON lnhibiton of JNK phosphorylation is possibly involved in the protection of melatonin on CA-induced tau hyperphosphorylation at Ser422 site.

Betaine Alleviates Hypertriglycemia and Tau Hyperphosphorylation in db/db Mice

Betaine supplementation has been shown to alleviate altered glucose and lipid metabolism in mice fed a high-fat diet or a high-sucrose diet. We investigated the beneficial effects of betaine in diabetic db/db mice. Alleviation of endoplasmic reticulum (ER) and oxidative stress was also examined in the livers and brains of db/db mice fed a betaine-supplemented diet. Male C57BL/KsJ-db/db mice were fed with or without 1% betaine for 5 wk (referred to as the db/db-betaine group and the db/db group, respectively). Lean non-diabetic db/+ mice were used as the control group. Betaine supplementation significantly alleviated hyperinsulinemia in db/db mice. Betaine reduced hepatic expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha, a major transcription factor involved in gluconeogenesis. Lower serum triglyceride concentrations were also observed in the db/db-betaine group compared to the db/db group. Betaine supplementation induced hepatic peroxisome proliferator-activated receptor alpha and carnitine palmitoyltransferase 1a mRNA levels, and reduced acetyl-CoA carboxylase activity. Mice fed a betaine-supplemented diet had increased total glutathione concentrations and catalase activity, and reduced lipid peroxidation levels in the liver. Furthermore, betaine also reduced ER stress in liver and brain. c-Jun N-terminal kinase activity and tau hyperphosphorylation levels were lower in db/db mice fed a betaine-supplemented diet, compared to db/db mice. Our findings suggest that betaine improves hyperlipidemia and tau hyperphosphorylation in db/db mice with insulin resistance by alleviating ER and oxidative stress.

The role of cyclin-dependent kinase 5/P25 kinase activation on apoptosis of retinal cell in RCS rat / 中华实验眼科杂志

Background Retinitis pigmentosa (RP)is a common hereditary blinding eye disease in ophthalmology.Current researches documented that RP may have the common pathophysiologic basis to Alzheimer disease and chronic neurodegenerative disease.Understanding this mechanism will offer a new therapeutic target for RP.Objective The purpose of the present study was to investigate the roles of cyclin-dependent kinase 5 (Cdk5)/P25 activation in the apoptosis of retinal neural cells of RCS rats.Methods Eighteen SPF RCS rats and 18 RCS-rdy+ rats were randomized into 17-,25-and 35-day groups respectively and 6 rats for each.The rats were sacrificed at corresponding time points and retinal hemogenete was prepared.Expressions of CdkS,P35,P25 and tau phosphorylation in the retinas were detected by Western blot,and the kinase activity of Cdk5/P25 was analyzed by quantitative colorimetric assay.Results The expressing level of P35 protein(A340) in the retinas of 17-day-old RCS rats was near that of 17-day-old RCS-rdy+ rats(t =0.52,P＞0.05).In 25-and 35-day-old RCS rats,the expressing levels of P35 protein were 2.20±0.48 and 1.23±0.14,which were higher than those of RCS-rdy+ rats(1.43±0.13 and 0.93±0.10),showing significant differences between them(t =3.78,4.28,P＜0.05).The expression of P25 was undetectable at postnatal 17 days in RCS rats and RCS-rdy+ rats,but it showed significantly higher in RCS rats(0.300±0.003 and 0.230±0.004) than that in RCS-rdy+ rats(0.040±0.004 and 0.070±0.004) at postnatal 25 days and 35 days(t=121.81,77.51,P＜0.01).No significant difference was found in the expression of Cdk5 in RCS rats and RCS-rdy+ rats at different ages (t =-0.60,0.19,1.62,P＞ 0.05).The kinase activity of Cdk5/P25 did not show significantly different between RCS and RCS-rdy+ rats at postnatal 17 days(t =0.19,P＞0.05),but significantly higher kinase activity of Cdk5/P25 was seen in RCS rats (0.0058 ±0.0005 and 0.0056±0.0004) than that in RCS-rdy+ rats(0.0038±0.0003 and 0.0032 ±0.0007) at postnatal 25 days and 35 days (t =8.07,5.97,P＜ 0.01).No expression of tau phosphorylation was detected in RCS rats at postnatal 17 days,but significantly higher tau phosphorylation level was seen in RCS rats at postnatal 25 days and 35 days(1.80±0.22 and 1.23±0.17),which were significant different in comparison with RCS-rdy+ rats at postnatal 25 days and 35 days(1.60 ±0.20 and 1.04 ±0.12)(t=4.71,3.17,P＜0.05).Conclusions The Cdk5/P25 kinase activity shows a consistent trend with theexpressions of P25 and tau phosphorylation in the RCS rats,indicating that the upregulation of P25 induces the enhance of enzyme activity of Cdk5,which phosphorylate its substrates to result in more apoptosis of retinal neural cells.

Influence of presenilin 1 overexpression on endogenous tau phosphorylation in neuroblastoma cells / 复旦学报（医学版）

Purpose To study the effect of overexpressing either wild type or a familial Alzheimer disease mutant presenilin 1 (mPS1) on tau phosphorylation in neuroblastoma NG-108 cells. Methods Three different plasmids transfected NG-108 cells respectively. Immunostaining and confocal microscopic technique were used to study the distribution of presenilin 1 and phosphorylated tau. Immunoblot test was applied to investigate the change of tau phosphorylation. Results Immunostaining showed that in brain of sporadic Alzheimer disease, PS1 mainly distributed in neuron and partially colocalized with the phosphorylated tau. Immunoblot tests showed that the cells transected either wild type PS1 or mPS1 contained more phorphorylated tau than the control cells. However, MTT test showed no significant difference between mock transfected cells and the wPS1 or mPS1 transfected cells. In addition, after transfection of the constructed PS1-EGFP vector, overexpressed EGFP-PS1 was located at cell surface membrane and subcellular organelles at earlier time at 12 hr, then EGFP-PS1 diffused in cytosol. Immunocytochemical observations demonstrated that some of the PS1-EGFP transfected cells contained more phosphorylated tau protein, which formed aggresome with PS-1-EGFP. When treated with phosphotase inhibitor okadaic acid, in the PS1-EGFP transfected cells accumulated more phosphorylated tau than the un-transfected cells. Conclusions Wild type PS1 is possibly involved in tauopathy in sporadic Alzheimer's disease.

Effects of lithium on CDK5 and PP2A expressions in chronic aluminum exposure rats / 西安交通大学学报(医学版)

Objective To explore the effects of lithium on expressions of cyclin-dependent kinase 5 (CDK5) and protein phosphatase 2A (PP2A) in the brains of chronic aluminum exposure rats so as to further understand the mechanism of lithium's inhibition on tau phosphorylation. Methods We divided 12 chronic aluminum chloride exposure rats into treatment group and non-treatment group (6 rats in each). Treatment group was given lithium chloride (200 mg/kg?d) via gastric perfusion daily for 6 weeks,while the non-treatment group sodium chloride at the same dosage and the normal group (6 non-aluminum exposure rats of the same month old) without intervention. Six weeks later,all the rats received Morris water maze test for learning memory function; CDK5 and PP2A expressions and phosphorylated tau protein level in rat hippocampus were determined by Western blotting. Results Compared with normal group,non-treatment of chronic aluminum exposure group showed higher phosphorylated tau protein level and CDK5 expression in the brain (P0.05). Conclusion Lithium may reduce tau phosphorylation and neurofibrillary tangle formation by inhibiting the expression of CDK5.