Alzheimer Disease ; genetics ; metabolism ; therapy ; Humans ; tau Proteins ; genetics ; metabolism

Objective To study the effects of TYRO protein kinase-binding protein (TYROBP) deficiency on learning behavior, glia activation and pro-inflammatory cycokines, and Tau phosphorylation of a new Alzheimer's disease (AD) mouse model carrying a PSEN1 p.G378E mutation.Methods A new AD mouse model carrying PSEN1 p.G378E mutation was built based on our previously found AD family which might be ascribed to the PSEN1 mutation, and then crossed with TYROBP deficient mice to produce the heterozygous hybrid mice (PSEN1^G378E/WT; Tyrobp^+/-) and the homozygous hybrid mice (PSEN1^G378E/G378E; Tyrobp^-/-). Water maze test was used to detect spatial learning and memory ability of mice. After the mice were sacrificed, the hippocampus was excised for further analysis. Immunofluorescence was used to identify the cell that expresses TYROBP and the number of microglia and astrocyte. Western blot was used to detect the expression levels of Tau and phosphorylated Tau (p-Tau), and ELISA to measure the levels of pro-inflammatory cytokines. Results Our results showed that TYROBP specifically expressed in the microglia of mouse hippocampus. Absence of TYROBP in PSEN1^G378E mutation mouse model prevented the deterioration of learning behavior, decreased the numbers of microglia and astrocytes, and the levels of interleukin-6, interleukin-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 (PSEN1^G378E/G378E; Tyrobp^-/- mice) compared with PSEN1^G378E/G378E mice (all P < 0.05). Conclusions TYROBP deficiency might play a protective role in the modulation of neuroinflammation of AD. However, the relationship between neuroinflammation processes involving microglia and astrocyte activation, and release of pro-inflammatory cytokines, and p-Tau pathology needs further study.
Mice ; Animals ; Alzheimer Disease/genetics* ; Neuroinflammatory Diseases ; Hippocampus/pathology* ; Mutation ; Cytokines/pharmacology* ; Disease Models, Animal ; tau Proteins/pharmacology* ; Amyloid beta-Peptides/metabolism* ; Adaptor Proteins, Signal Transducing/pharmacology*

The receptor for advanced glycation end products (RAGE) has been reported to have a pivotal role in the pathogenesis of Alzheimer's disease (AD). This study investigated RAGE levels in the hippocampus and cortex of a triple transgenic mouse model of AD (3xTg-AD) using western blotting and immunohistochemical double-labeling to assess cellular localization. Analysis of western blots showed that there were no differences in the hippocampal and cortical RAGE levels in 10-month-old adult 3xTg-AD mice, but significant increases in RAGE expression were found in the 22- to 24-month-old aged 3xTg-AD mice compared with those of age-matched controls. RAGE-positive immunoreactivity was observed primarily in neurons of aged 3xTg-AD mice with very little labeling in non-neuronal cells, with the notable exception of RAGE presence in astrocytes in the hippocampal area CA1. In addition, RAGE signals were co-localized with the intracellular amyloid precursor protein (APP)/amyloid beta (Abeta) but not with the extracellular APP/Abeta. In aged 3xTg-AD mice, expression of human tau was observed in the hippocampal area CA1 and co-localized with RAGE signals. The increased presence of RAGE in the 3xTg-AD animal model showing critical aspects of AD neuropathology indicates that RAGE may contribute to cellular dysfunction in the AD brain.
Advanced Glycosylation End Product-Specific Receptor ; Alzheimer Disease/genetics/*metabolism ; Amyloid beta-Peptides/metabolism ; Animals ; Astrocytes/*metabolism ; CA1 Region, Hippocampal/growth & development/metabolism/pathology ; Humans ; Mice ; Mice, Transgenic ; Neurons/*metabolism ; Receptors, Immunologic/genetics/*metabolism ; tau Proteins/genetics/metabolism

OBJECTIVETo construct a prokaryotic expression vector of human tau multiepitope peptide for examining the immunogenicity of a TauP1/P2 DNA vaccine in mice using the expressed product.

METHODSThe coding sequence of Tau multiepitope peptide gene was amplified from the plasmid pVAX1-Tau by PCR and inserted into the prokaryotic expression vector pGEX-4T-2 to construct the recombinant plasmid pGEX-4T-2-TauP1/P2. The positive recombinants were transformed into E.coli BL21 cells, and the expression of fusion protein GST-TauP1/P2 was induced by IPTG and identified by SDS-PAGE. Mice was immunized with TauP1/P2 DNA vaccine and the production of the specific antibodies was detected by Dot-blot analysis using the purified fusion protein.

RESULTSA gene fragment 300 bp in length was amplified. Enzyme digestion and DNA sequencing verified correct construction of the prokaryotic expression plasmid pGEX-4T-2-TauP1/P2. The expression of target fusion protein GST-TauP1/P2 was detected by SDS-PAGE. Specific antibodies against TauP1/P2 were detected in the serum of mice immunized with the DNA vaccine using GST-TauP1/P2 fusion protein.

CONCLUSIONThe constructed prokaryotic expression plasmid of human Tau multiepitope peptide is capable of expressing the target fusion protein, which specifically recognizes the specific antibodies against TauP1/P2 in mice immunized with TauP1/P2 DNA vaccine.

Animals ; Epitopes ; immunology ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Humans ; Mice ; Mice, Inbred C57BL ; Peptides ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Vaccines, DNA ; biosynthesis ; immunology ; tau Proteins ; biosynthesis ; genetics ; immunology

OBJECTIVETo explore the effect of different culture media on viability and expression of tau protein in organotypic hippocampal slice.

METHODSBrain slices (400 microm) from 1, 2, 4, and 8 week-old Wistar rats were prepared and cultured in minimum essential medium (MEM) or Dulbecco's modified eagle medium: nutrient mixture (DMEM/F12) medium respectively for 21 days. Viability of the slices was measured by lactate dehydrogenase (LDH) assay and expression of tau protein was detected by Western blot.

RESULTSThe viability of the slices was not influenced significantly by the two different culture media, while the expression level of tau protein was significantly higher in DMEM/F12 than in MEM (P < 0.05), especially in the slices from 2 and 4 week-old rats.

CONCLUSIONThe slices from 2 or 4 week-old rat hippocampi and DMEM/F12 medium may be the preferred choice for tau associated researches. An ideal Alzheimer's disease model may be established based on the results of these researches.

Animals ; Culture Media ; Hippocampus ; growth & development ; metabolism ; L-Lactate Dehydrogenase ; biosynthesis ; Organ Culture Techniques ; methods ; Rats ; Rats, Wistar ; tau Proteins ; biosynthesis ; genetics

OBJECTIVETo study the effect of Panax notoginseng saponins (PNS) on (synaptophysin, syp) and tau gene expression in the brain tissue in senescence accelerated mouse prone 8 (SAMP 8).

METHODSAMP8 were randomly divided into 4 groups: PNS 23.38, 93.50 mg x kg(-1) group, huperzin A 0.038 6 mg x kg(-1) x d(-1) group and blank control group; the drug groups were treated with the designed drugs respectively per day by intragastric administration for 4 consecutive weeks, and double distilled water was given to blank control group. After treatment, the mRNA content of tau and syp were assayed by reverse transcription (RT) and real-time polymerase chain reaction (real-time PCR).

RESULTCompared with blank control group, the syp mRNA contents were increased in PNS groups (P < 0.05 or P < 0.01), and the tau mRNA content were not significant difference in all groups.

CONCLUSIONThis study suggests that PNS can up-regulate syp gene expression at transcriptional level in the brain of SAMP 8.

Aging ; drug effects ; metabolism ; Animals ; Brain ; drug effects ; metabolism ; Gene Expression ; drug effects ; genetics ; Mice ; Panax notoginseng ; chemistry ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; genetics ; metabolism ; Saponins ; pharmacology ; tau Proteins ; genetics ; metabolism

OBJECTIVETo explore the relations among apolipoprotein E4, Tau protein and glycogen synthase kinase 3β (GSK-3β).

METHODSU87 cells were transfected with pIRES-EGFP (control) or the recombinant plasmids ApoE4/pIRES-EGFP or ApoE3/pIRES-EGFP, and the expression levels of p-Tau/Tau and GSK-3β in the cells were examined with Western blotting. To further confirm the effect of ApoE on GSK-3β and p-Tau expressions, a short interfering RNA (siRNA) targeting ApoE (ApoE-siRNA) was transfected into U87 cells via Lipofectamine 2000 and the protein expressions were examined 24 h later.

RESULTSCompared with those in the control group, the expressions levels of both GSK-3β and p-Tau/Tau increased significantly in the cells transfected with ApoE4 and ApoE3 plasmids (P<0.01), and the ApoE4 plasmid produced a more potent effect than the ApoE3 plasmid on the protein expressions (P<0.01). ApoE knockdown resulted in significantly reduced expressions of GSK-3β (P<0.001) and p-Tau (P<0.01) in the cells.

CONCLUSIONApoE4 can enhance Tau phosphorylation though upregulating GSK-3β, which sheds light on a new role of ApoE4 in Alzheimer's disease.

Alzheimer Disease ; genetics ; Apolipoprotein E3 ; genetics ; Apolipoprotein E4 ; genetics ; Cell Line ; Gene Silencing ; Glycogen Synthase Kinase 3 beta ; genetics ; metabolism ; Humans ; Phosphorylation ; RNA, Small Interfering ; genetics ; Transfection ; tau Proteins ; metabolism

OBJECTIVETo study the effect of Tiaoxin Recipe (TXR) on learning and memory related gene expression in hippocampus of senescence accelerated mice (SAM).

METHODSChanges of learning and memory related gene expression, including mineralocorticoid receptor (MR), presenile protein 1 and 2 (PS-1, PS-2), tau, APP, apoE and bcl-2 in hippocampus of SAM were determined by reverse transcription polymerase chain reaction (RT-PCR). The effect of TXR were tested. E2020 was used as the drug for control.

RESULTSCompared with those in the same aged mice, in the 5-month old SAM, levels of gene expression of MR, tau, PS-2 and APP were significantly higher, that of apo-E lower, levels of gene expression PS-1 and bcl-2 were unobviously changed; while in the 12-month old SAM, gene expression of MR and tau were higher, bcl-2 was lower and PS-1, PS-2, apoE and APP were also unobviously changed. Continuously orally taken TXR could correct the abnormality of MR, tau and apoE gene expression in hippocampus of 5-month SAM and that of MR and bcl-2 in 12-month SAM.

CONCLUSIONContinuously orally taken of TXR has the effect of regulating and correcting learning and memory related gene expression in hippocampus of 5-month and 12-month SAM.

Aging ; drug effects ; metabolism ; Animals ; Apolipoproteins E ; biosynthesis ; genetics ; Gene Expression ; Hippocampus ; metabolism ; Learning ; drug effects ; Membrane Proteins ; biosynthesis ; genetics ; Memory ; drug effects ; Mice ; Presenilin-1 ; Presenilin-2 ; tau Proteins ; biosynthesis ; genetics

Alzheimer disease (AD) is a common neurodegenerative disease. Drosophila has been regard as one of the ideal models for Alzheimer because of its unique advantage on genetic manipulation. AD transgenic drosophila models not only help to elucidate the pathogenesis of Alzheimer disease, but also provide potential screening models for drugs to treat the disease. In this review, we summarize the recent research progress using AD transgenic drosophila.
Alzheimer Disease ; etiology ; genetics ; metabolism ; Amyloid beta-Peptides ; metabolism ; Animals ; Animals, Genetically Modified ; genetics ; Disease Models, Animal ; Drosophila ; genetics ; Drug Evaluation, Preclinical ; Gene Transfer Techniques ; Humans ; Phosphorylation ; tau Proteins ; metabolism

OBJECTIVETo study the association between Alzheimer' s disease (AD) and apolipoprotein E (apoE) polymorphism and apoE epsilon4 allele; and to investigate the role of apoE in senile plaque formation.

METHODSDuring the period from 1982 to 2003, 27 portmortem cases of AD from the archival files of Department of Pathology of Beijing Hospital, diagnosed according to the consortium to establish a registry for Alzheimer's disease (CERAD) criteria, were enrolled into this study. Among the 27 cases studied, there were 23 cases of definite AD and 4 cases of probable AD. Postmortem brain tissues from 67 neurologically unremarkable deceased were used as age-matched controls. Immunohistochemical study for beta-amyloid (Abeta) and Tau protein, as well as immunohistochemical study for Abeta/apoE, were performed in all AD cases using streptavidin-peroxidase (SP) and double immunostaining ( SP/ABC) methods, respectively. Senile plaques and neurofibrillary tangles in the 23 cases of definite AD were further quantified. The apoE genotypes in all cases were analyzed by polymerase chain reaction and restriction fragment length polymorphism technologies.

RESULTSImmunohistochemical study for Abeta distinguished 4 different types of senile plaques: diffuse non-neuritic plaques, diffuse neuritic plaques, dense-core neuritic plaques and dense-core non-neuritic plaques. Double immunohistochemistry for Abeta/apoE showed that some senile plaques were positive for both Abeta and apoE. The expression rates for Abeta and apoE in these 4 different types of senile plaques were 4. 28%, 84. 71%, 8.50% and 2.51%, respectively. The positivity rate for Abeta/apoE in diffuse neuritic plaques were significantly higher than those in other 3 types (P < 0.01). The frequency of occurrence of apoE epsilon4 allele in AD was significantly higher than that in the control group (P < 0.01). The numbers of senile plaques and neurofibrillary tangles in AD cases with apoE epsilon4 allele were also significantly higher than those in AD cases without apoE epsilon4 allele (P < 0.01).

CONCLUSIONSApoE polymorphism is associated with AD. The presence of apoE epsilon4 allele carries a higher risk for the development of AD. ApoE may also play an important role in the transformation of diffuse non-neuritic plaques to diffuse neuritic plaques.

Aged ; Aged, 80 and over ; Alleles ; Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; metabolism ; Apolipoproteins E ; genetics ; metabolism ; Brain ; metabolism ; pathology ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Neurofibrillary Tangles ; pathology ; Plaque, Amyloid ; pathology ; tau Proteins ; metabolism