Objective To explore the effect of knocking down Rho-associated coiled-coil kinase (ROCK2) gene on the cognitive function of amyloid precursor protein/presenilin-1 (APP/PS1) double transgenic mice and its mechanism. Methods APP/PS1 double transgenic mice were randomly divided into AD model group (AD group), ROCK2 gene knock-down group (shROCK2 group), ROCK2 gene knock-down control group (shNCgroup), and wild-type C57BL/6 mice of the same age served as the wild-type control (WT group). Morris water maze and Y maze were employed to test the cognitive function of mice. Neuron morphology was detected by Nissl staining. Immunofluorescence histochemical staining was used to detect the expression of phosphorylated dynamin-related protein 1 (p-Drp1) and mitochondrial fusion 1 (Mfn1). Western blot analysis was used to detect the expression ROCK2, cleaved-caspase-3 (c-caspase-3), B-cell lymphoma 2 (Bcl2), Bcl2-related protein X (BAX), p-Drp1, mitochondrial fission 1 (Fis1), optic atrophy 1 (OPA1), Mfn1 and Mfn2. Results Compared with AD group mice, the expression of ROCK2 in shROCK2 group mice was significantly reduced; the cognitive function was significantly improved with the number of neurons in the hippocampal CA3 and DG areas increasing, and nissl bodies were deeply stained; the expression of c-caspase-3 and BAX was decreased, while the expression of Bcl2 was increased; the expression of mitochondrial division related proteins p-Drp1 and Fis1 were decreased, while the expression of mitochondrial fusion-related proteins OPA1, Mfn1 and Mfn2 were increased. Conclusion Knock-down of ROCK2 gene can significantly improve the cognitive function and inhibit the apoptosis of nerve cells of APP/PS1 mice. The mechanism may be related to promoting mitochondrial fusion and inhibiting its division.
Animals ; Mice ; Alzheimer Disease/pathology* ; Amyloid beta-Peptides/metabolism* ; Amyloid beta-Protein Precursor ; Apoptosis/genetics* ; bcl-2-Associated X Protein ; Caspase 3 ; Cognition ; Disease Models, Animal ; Mice, Inbred C57BL ; Mice, Transgenic ; Mitochondrial Dynamics/genetics*

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*

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease featuring progressive cognitive impairment. Although the etiology of late-onset AD remains unclear, the close association of AD with apolipoprotein E (APOE), a gene that mainly regulates lipid metabolism, has been firmly established and may shed light on the exploration of AD pathogenesis and therapy. However, various confounding factors interfere with the APOE-related AD risk, raising questions about our comprehension of the clinical findings concerning APOE. In this review, we summarize the most debated factors interacting with the APOE genotype and AD pathogenesis, depict the extent to which these factors relate to APOE-dependent AD risk, and discuss the possible underlying mechanisms.
Alzheimer Disease/pathology* ; Apolipoprotein E4/genetics* ; Apolipoproteins E/genetics* ; Genotype ; Humans ; Lipid Metabolism ; Neurodegenerative Diseases ; Risk Factors

Alzheimer's disease (AD) is the most common form of dementia among the elderly, characterized by amyloid plaques, neurofibrillary tangles, and neuroinflammation in the brain, as well as impaired cognitive behaviors. A sex difference in the prevalence of AD has been noted, while sex differences in the cerebral pathology and relevant molecular mechanisms are not well clarified. In the present study, we systematically investigated the sex differences in pathological characteristics and cognitive behavior in 12-month-old male and female APP/PS1/tau triple-transgenic AD mice (3×Tg-AD mice) and examined the molecular mechanisms. We found that female 3×Tg-AD mice displayed more prominent amyloid plaques, neurofibrillary tangles, neuroinflammation, and spatial cognitive deficits than male 3×Tg-AD mice. Furthermore, the expression levels of hippocampal protein kinase A-cAMP response element-binding protein (PKA-CREB) and p38-mitogen-activated protein kinases (MAPK) also showed sex difference in the AD mice, with a significant increase in the levels of p-PKA/p-CREB and a decrease in the p-p38 in female, but not male, 3×Tg-AD mice. We suggest that an estrogen deficiency-induced PKA-CREB-MAPK signaling disorder in 12-month-old female 3×Tg-AD mice might be involved in the serious pathological and cognitive damage in these mice. Therefore, sex differences should be taken into account in investigating AD biomarkers and related target molecules, and estrogen supplementation or PKA-CREB-MAPK stabilization could be beneficial in relieving the pathological damage in AD and improving the cognitive behavior of reproductively-senescent females.
Alzheimer Disease ; metabolism ; pathology ; psychology ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Disease Models, Animal ; Female ; Hippocampus ; metabolism ; pathology ; Humans ; Inflammation ; metabolism ; pathology ; psychology ; Male ; Maze Learning ; physiology ; Mice, Inbred C57BL ; Mice, Transgenic ; Neurofibrillary Tangles ; metabolism ; pathology ; Plaque, Amyloid ; metabolism ; pathology ; psychology ; Presenilin-1 ; genetics ; metabolism ; Sex Characteristics ; Spatial Memory ; physiology ; p38 Mitogen-Activated Protein Kinases ; metabolism ; tau Proteins ; genetics ; metabolism

Astrocytes are closely associated with Alzheimer's disease (AD). However, their precise roles in AD pathogenesis remain controversial. One of the reasons behind the different results reported by different groups might be that astrocytes were targeted at different stages of disease progression. In this study, by crossing hAPP (human amyloid precursor protein)-J20 mice with a line of GFAP-TK mice, we found that astrocytes were activated specifically at an early stage of AD before the occurrence of amyloid plaques, while microglia were not affected by this crossing. Activation of astrocytes at the age of 3-5 months did not affect the proteolytic processing of hAPP and amyloid plaque loads in the brains of hAPP-J20 mice. Our data suggest that early activation of astrocytes does not affect the deposition of amyloid β in an animal model of AD.
Aldehyde Dehydrogenase ; metabolism ; Alzheimer Disease ; genetics ; metabolism ; pathology ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Astrocytes ; metabolism ; Brain ; pathology ; Calcium-Binding Proteins ; metabolism ; Cell Proliferation ; Disease Models, Animal ; Gene Expression Regulation ; genetics ; Glial Fibrillary Acidic Protein ; Glutamine ; metabolism ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Ki-67 Antigen ; metabolism ; Mice ; Mice, Transgenic ; Microfilament Proteins ; metabolism ; Mutation ; genetics ; Nerve Tissue Proteins ; metabolism

BACKGROUNDAmyloid β (Aβ) has been established as a key factor for the pathological changes in the brains of patients with Alzheimer's disease (AD), and cellular senescence is closely associated with aging and cognitive impairment. However, it remains blurred whether, in the AD brains, Aβ accelerates the neuronal senescence and whether this senescence, in turn, impairs the cognitive function. This study aimed to explore the expression of senescence-associated genes in the hippocampal tissue from young to aged 5XFAD mice and their age-matched wild type (WT) mice to determine whether senescent neurons are present in the transgenic AD mouse model.

METHODSThe 5XFAD mice and age-matched wild type mice, both raised from 1 to 18 months, were enrolled in the study. The senescence-associated genes in the hippocampus were analyzed and differentially expressed genes (DEGs) were screened by quantitative real-time polymerase chain reaction. Cognitive performance of the mice was evaluated by Y-maze and Morris water maze tests. Oligomeric Aβ (oAβ) (1-42) was applied to culture primary neurons to simulate the in vivo manifestation. Aging-related proteins were detected by Western blotting analysis and immunofluorescence.

RESULTSIn 5XFAD mice, of all the DEGs, the senescence-associated marker p16 was most significantly increased, even at the early age. It was mainly localized in neurons, with a marginal expression in astrocytes (labeled as glutamine synthetase), nil expression in activated microglia (labeled as Iba1), and negatively correlated with the spatial cognitive impairments of 5XFAD mice. oAβ (1-42) induced the production of senescence-related protein p16, but not p53 in vitro, which was in line with the in vivo manifestation.

CONCLUSIONSoAβ-accelerated neuronal senescence may be associated with the cognitive impairment in 5XFAD mice. Senescence-associated marker p16 can serve as an indicator to estimate the cognitive prognosis for AD population.

Alzheimer Disease ; metabolism ; physiopathology ; Amyloid Precursor Protein Secretases ; genetics ; metabolism ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; metabolism ; Animals ; Aspartic Acid Endopeptidases ; genetics ; metabolism ; Brain ; metabolism ; physiopathology ; Cells, Cultured ; Cellular Senescence ; genetics ; physiology ; Cognition ; physiology ; Cognition Disorders ; metabolism ; physiopathology ; Disease Models, Animal ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Neurons ; metabolism ; pathology ; Real-Time Polymerase Chain Reaction

This study aimed to investigate the independent and interactive influences of apolipoprotein E (APOE) epsilon4 and beta-amyloid (Abeta) on multiple cognitive domains in a large group of cognitively normal (CN) individuals and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Participants were included if clinical and cognitive assessments, amyloid imaging, and APOE genotype were all available from the Alzheimer's Disease Neuroimaging Initiative database (CN = 324, MCI = 502, AD = 182). Individuals with one or two copies of epsilon4 were designated as APOE epsilon4 carriers (epsilon4+); individuals with no epsilon4 were designated as APOE epsilon4 non-carriers (epsilon4-). Based on mean florbetapir standard uptake value ratios, participants were classified as Abeta burden-positive (Abeta+) or Abeta burden-negative (Abeta-). In MCI, APOE epsilon4 effects were predominantly observed on frontal executive function, with epsilon4+ participants exhibiting poorer performances; Abeta positivity had no influence on this effect. Abeta effects were observed on global cognition, memory, and visuospatial ability, with Abeta+ participants exhibiting poorer performances. Measures of frontal executive function were not influenced by Abeta. Interactive effects of APOE epsilon4+ and Abeta were observed on global cognition and verbal recognition memory. Abeta, not APOE epsilon4+, influenced clinical severity and functional status. The influences of APOE epsilon4+ and Abeta on cognitive function were minimal in CN and AD. In conclusion, we provide further evidence of both independent and interactive influences of APOE epsilon4+ and Abeta on cognitive function in MCI, with APOE epsilon4+ and Abeta showing dissociable effects on executive and non-executive functions, respectively.
Aged ; Aged, 80 and over ; Alzheimer Disease/genetics/pathology ; Amyloid beta-Peptides/*metabolism ; Aniline Compounds/chemistry ; Apolipoprotein E4/*genetics ; Brain/radiography ; Cognition ; Databases, Factual ; Demography ; Ethylene Glycols/chemistry ; Female ; Genotype ; Humans ; Male ; Mild Cognitive Impairment/genetics/*pathology ; Positron-Emission Tomography

Microglia play a pivotal role in clearance of Aβ by degrading them in lysosomes, countering amyloid plaque pathogenesis in Alzheimer's disease (AD). Recent evidence suggests that lysosomal dysfunction leads to insufficient elimination of toxic protein aggregates. We tested whether enhancing lysosomal function with transcription factor EB (TFEB), an essential regulator modulating lysosomal pathways, would promote Aβ clearance in microglia. Here we show that microglial expression of TFEB facilitates fibrillar Aβ (fAβ) degradation and reduces deposited amyloid plaques, which are further enhanced by deacetylation of TFEB. Using mass spectrometry analysis, we firstly confirmed acetylation as a previously unreported modification of TFEB and found that SIRT1 directly interacted with and deacetylated TFEB at lysine residue 116. Subsequently, SIRT1 overexpression enhanced lysosomal function and fAβ degradation by upregulating transcriptional levels of TFEB downstream targets, which could be inhibited when TFEB was knocked down. Furthermore, overexpression of deacetylated TFEB at K116R mutant in microglia accelerated intracellular fAβ degradation by stimulating lysosomal biogenesis and greatly reduced the deposited amyloid plaques in the brain slices of APP/PS1 transgenic mice. Our findings reveal that deacetylation of TFEB could regulate lysosomal biogenesis and fAβ degradation, making microglial activation of TFEB a possible strategy for attenuating amyloid plaque deposition in AD.
Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; chemistry ; genetics ; metabolism ; Brain ; metabolism ; Cells, Cultured ; Chloride Channels ; genetics ; metabolism ; Disease Models, Animal ; HEK293 Cells ; Humans ; Lysosomes ; genetics ; metabolism ; Mice ; Mice, Transgenic ; Microglia ; cytology ; metabolism ; Mutagenesis, Site-Directed ; Peptides ; analysis ; chemistry ; Protein Binding ; RNA Interference ; Sirtuin 1 ; antagonists & inhibitors ; genetics ; metabolism

OBJECTIVETo study the effect of Tiantai No. 1 [symbol in text] on gene expression profile in hippocampus of Alzheimer's disease (AD) rat, molecular genetic target points of the effect of this drug were defined, its molecular genetic pharmacodynamic mechanism of anti-AD was further explored at molecular gene level, and a scientific basis was provided for its clinical availability and promotion.

METHODSThirty male Sprague-Dawley rats were divided into three groups with 10 rats per group: sham-operation group, model group and Tiantai No. 1 group. Sterile surgical procedure was applied, the model group with bilateral hippocampal injection of Aβ1-40 was established, and normal saline was used instead of Aβ1-40 in the sham-operation group. One week after the models was made, rats were administered by gastric lavage once every day for three consecutive weeks. The rats of the sham-operation group and the model group were daily fed with purified water by lavage; the rats of the Tiantai No.1 group treated group were administered with Tiantai No.1 by lavage. Total RNAs of hippocampus tissues were extracted with Trizol, the changes of hippocampus gene expression profiles in the above three groups were analyzed by using Affymetrix rat whole genome expression profile microarray.

RESULTSMicroarray analysis showed that, compared with the sham-operation group, the hippocampus of the model group had 50 up-regulated genes with significant difference (fold change >2), and 21 down-regulated genes with significant difference (fold change <0.5); compared with the hippocampus of the model group, the hippocampus of the Tiantai No. 1 group was found to have 5 up-regulated genes with significant difference (fold change >2) and 20 down-regulated genes with significant difference (fold change <0.5). The functions of differentially expressed genes of the groups were involved in nervous system's development, neuronic differentiation and function-regulation, cellular growth and differentiation and apoptosis, synaptic occurrence and plasticity, inflammation and immune response, ion channels/transporters, cellular signal transduction, cellular material/energy metabolism and so on.

CONCLUSIONTiantai No. 1 can regulate hippocampal function, and further regulate the brain function of animals in multiple gene target points by a number of ways.

Alzheimer Disease ; genetics ; pathology ; Animals ; Body Weight ; drug effects ; Computational Biology ; methods ; Drugs, Chinese Herbal ; pharmacology ; Electrophoresis, Agar Gel ; Gene Expression Profiling ; Gene Expression Regulation ; drug effects ; Hippocampus ; drug effects ; metabolism ; pathology ; Male ; Nucleic Acid Denaturation ; Organ Size ; drug effects ; RNA ; isolation & purification ; metabolism ; Rats, Sprague-Dawley

Cholesterol is an essential component for neuronal physiology not only during development stage but also in the adult life. Cholesterol metabolism in brain is independent from that in peripheral tissues due to blood-brain barrier. The content of cholesterol in brain must be accurately maintained in order to keep brain function well. Defects in brain cholesterol metabolism has been shown to be implicated in neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), and some cognitive deficits typical of the old age. The brain contains large amount of cholesterol, but the cholesterol metabolism and its complex homeostasis regulation are currently poorly understood. This review will seek to integrate current knowledge about the brain cholesterol metabolism with molecular mechanisms.
ATP-Binding Cassette Transporters ; genetics ; metabolism ; Alzheimer Disease ; genetics ; metabolism ; pathology ; Blood-Brain Barrier ; Brain ; metabolism ; pathology ; Cholesterol ; metabolism ; Gene Expression Regulation ; Homeostasis ; Humans ; Huntington Disease ; genetics ; metabolism ; pathology ; Hydroxycholesterols ; metabolism ; Lipid Metabolism ; genetics ; Neurons ; metabolism ; pathology ; Parkinson Disease ; genetics ; metabolism ; pathology ; Receptors, Lipoprotein ; genetics ; metabolism