The relationship between overexpression of Slit2 and accumulation of amyloid-β in aging mice studied by PCR array / 中国实验动物学报

Objective Previous studies suggested that overerpression of Slit2 results in abnormal Alzheimer's disease-like behavior and cognition impairment in mice. The aim of this study is to investigate the relationship between overerpression of Slit2 and accumulation and clearance of amyloid-β in aging mice by comparing the differential expression of genes for accumulation and clearance of amyloid-β in aging Tg-Slit2 and Tg-2576 mice. Methods 14-month old male C57BL/6, Tg-Slit2 and Tg-2576 mice were used to detect the expression of Aβ1 - 40 and Aβ1 - 42 in brain by immunohistochemistry. Further, the total RNA in the brain of these mice were extracted, identified and inversely transcripted to cDNA, then the cDNA was detected by PCR array. The expression of genes in the brain of Tg-Slit2 and Tg-2576 mice were analyzed. Results Comparing with the Tg-2576 mice in the same age, accumulation of Aβ was not found in the brain of Tg-Slit2 and C57BL/6 mice. The result from PCR array analysis showed that comparing with the same aged C57BL/6 mice, there were 16 up-regulated genes and 8 down-regulated genes in the brain of Tg-Slit2 mice and 14 up-regulated genes and 17 down-regulated genes in the brain of Tg-Slit2 mice. The expression of amyloid beta precursor protein (APP) in the brain of the three group mice was not changed. The expression of presenilin 2 ( Psen2) related with Aβ production was significantly up-regulated in the Tg-2576 mice. In addition, the expression of low density lipoprotein receptor-related protein ( LRP) 6 and 9 were markedly decreased in the Tg-2576 mice. Notably, these genes were not changed in the brain of the aging Tg-Slit2 mice. Conclusions The accumulation of Aβ in the brain are not found in 14-month Tg-Slit2 mice, In addition, different from Tg-2576 mice, the significant changes of expression of Aβ-related genes is not found in the brain of Tg-Slit2 mice.

Serum metabolic changes in a transgenic mouse model of Alzheimer's disease / 中国实验动物学报

Objective To provide a basis for clinical diagnosis,a serum metabonomic dynamic study was carried out on the Tg2576 mouse model at different stages of Alzheimer's disease(AD) whose pathological progress is similar to that of human AD patients.Methods Serum samples of Tg2576 mice were collected at the early(6 months) and late(12 months) stages of Alzheimer's disease.The 1H NMR spectra of the serum samples were collected and the metabolic characteristics were analyzed by multivariate analysis.Results Significant differences in serum metabonomics were found in the transgenic Tg2576 mice and C57 mice at 6 and 12 months of age,and there were significant metabolic changes in Tg2576 mice at different stages of Alzheimer's disease.Compared with C57 mice,the Tg2576 mice at early stage of Alzheimer's disease showed higher levels of serum lactate,myo-inositol and amino acids(such as leucine,isoleucine,alanine),and lower levels of lipids,choline,phosphorylcholine,glycerol phosphorglcholine,betaine,glycine and glucose.At the late stage of Alzheimer's disease,the transgenic Tg2576 mice had higher levels of lactate,myo-inositol and alanine,while the serum levels of lipids,choline,phosphorylcholine,glycerophosphorylcholine,betaine,and glycine continued to drop.Meanwhile glutamine and creatine levels started to decline.By comparing the early and late serum metabolites of Alzheimer's disease,serum metabonomic profiles of the late stage of Alzheimer's disease indicated an up-regulation of lactate,myo-inositol and alanine,and a down-regulation of lipids,choline,phosphorylcholine and glycerophosphorylcholinelevels.Moreover,the levels of lactate,lipids,choline,phosphorylcholine and glycerophosphorylcholine showed statistical significance at the early stage of AD,and they were closely correlated with the severity of Alzheimer's disease.Conclusions The above results show that the changes of lactate,myo-inositol and alanine are positively-correlated with the development of AD,while the serum levels of lipids,choline,phosphorylcholine and glycerophosphorylcholine are inversely-proportional to the severity of AD.These metabolites are dynamically and progressively changed along with the disease progression,which hopefully may serve as early metabolic markers for the diagnosis of AD in clinical practice.

Diet rich in date palm fruits improves memory, learning and reduces beta amyloid in transgenic mouse model of Alzheimer’s disease.

Background: At present, the treatment options available to delay the onset or slow down the progression of Alzheimer’s disease (AD) are not effective. Recent studies have suggested that diet and lifestyle factors may represent protective strategies to minimize the risk of developing AD. Date palm fruits are a good source of dietary fiber and are rich in total phenolics and natural antioxidants, such as anthocyanins, ferulic acid, protocatechuic acid and caffeic acid. These polyphenolic compounds have been shown to be neuroprotective in different model systems. Objective: We investigated whether dietary supplementation with 2% and 4% date palm fruits (grown in Oman) could reduce cognitive and behavioral deficits in a transgenic mouse model for AD (amyloid precursor protein [APPsw]/Tg2576). Materials and Methods: The experimental groups of APP‑transgenic mice from the age of 4 months were fed custom‑mix diets (pellets) containing 2% and 4% date fruits. We assessed spatial memory and learning ability, psychomotor coordination, and anxiety‑related behavior in all the animals at the age of 4 months and after 14 months of treatment using the Morris water maze test, rota‑rod test, elevated plus maze test, and open‑field test. We have also analyzed the levels of amyloid beta (Aβ) protein (1–40 and 1–42) in plasma of control and experimental animals. Results: Standard diet‑fed Tg mice showed significant memory deficits, increased anxiety‑related behavior, and severe impairment in spatial learning ability, position discrimination learning ability and motor coordination when compared to wild‑type on the same diet and Tg mice fed 2% and 4% date supplementation at the age of 18 months. The levels of both Aβ proteins were significantly lowered in date fruits supplemented groups than the Tg mice without the diet supplement. The neuroprotective effect offered by 4% date fruits diet to AD mice is higher than 2% date fruits diet. Conclusions: Our results suggest that date fruits dietary supplementation may have beneficial effects in lowering the risk, delaying the onset or slowing down the progression of AD.

Amyloid Precursor Protein Binding Protein-1 Is Up-regulated in Brains of Tg2576 Mice

Amyloid precursor protein binding protein-1 (APP-BP1) binds to the carboxyl terminus of amyloid precursor protein and serves as a bipartite activation enzyme for the ubiquitin-like protein, NEDD8. Previously, it has been reported that APP-BP1 rescues the cell cycle S-M checkpoint defect in Ts41 hamster cells, that this rescue is dependent on the interaction of APP-BP1 with hUba3. The exogenous expression of APP-BP1 in neurons has been reported to cause DNA synthesis and apoptosis via a signaling pathway that is dependent on APP-BP1 binding to APP. These results suggest that APP-BP1 overexpression contributes to neurodegeneration. In the present study, we explored whether APP-BP1 expression was altered in the brains of Tg2576 mice, which is an animal model of Alzheimer's disease. APP-BP1 was found to be up-regulated in the hippocampus and cortex of 12 month-old Tg2576 mice compared to age-matched wild-type mice. In addition, APP-BP1 knockdown by siRNA treatment reduced cullin-1 neddylation in fetal neural stem cells, suggesting that APP-BP1 plays a role in cell cycle progression in the cells. Collectively, these results suggest that increased expression of APP-BP1, which has a role in cell cycle progression in neuronal cells, contributes to the pathogenesis of Alzheimer's disease.

THE EFFECT OF INOCULATING A? SUBUNIT VACCINE ON AMYLOID PLAQUES OF BRAIN AND COGNITIVE BEHAVIOR IN Tg2576 MICE / 解剖学报

Objective To investigate the effects of A? subunit vaccine immunization on amyloid plaques and behavioural impairment in Tg2576 mice. Methods Twenty-four Tg2576 mice were randomly divided into A?-(1-15) group,A?-(36-42) group,A?-(42) group and control group.Tg2576 mice were inoculated by corresponding vaccine in 9 month old.Indirect ELISA was used to assay antibody against A?-(42) in the serum and homogenate of brain.The method of immunohistochemical staining was performed to observe deposition of amyloid plaques and using method of Morris water maze to test mouse's learning and memory.Histochemical staining was used to observe the morphology of brain,liver,spleen,lung and kidney to assess safety of subunit vaccine. Results After the second inoculating,antibody against A?-(42) began to develop in experimental group mice.The titer increased with inoculating times.Once the inoculating was stopped,the titer of antibody was decreased.The low titer of antibody against A?-(42) could be also detected in supernatant of homogenated brain.After six month inoculating,amyloid deposition in cortex and hippocampi were significantly reduced in A?-(42),A?-(1-15) and A?-(36-42) group.Compared with control group,they were greatly decreased in experimental groups(P0.05).The effect of A?-(1-15) subunit vaccine had more superior than that of A?-(36-42) vaccine(P