Activity-dependent neuroprotective protein snippet NAP reduces tau hyperphosphorylation and enhances learning in a novel transgenic mouse model

Activity-dependent neuroprotective protein (ADNP) differentially interacts with chromatin to regulate essential genes. Because complete ADNP deficiency is embryonic lethal, the outcome of partial ADNP deficiency was examined. ADNP(+/-) mice exhibited cognitive deficits, significant increases in phosphorylated tau, tangle-like structures, and neurodegeneration compared with ADNP(+/+) mice. Increased tau hyperphosphorylation is known to cause memory impairments in neurodegenerative diseases associated with tauopathies, including the most prevalent Alzheimer's disease. The current results suggest that ADNP is an essential protein for brain function and plays a role in normal cognitive performance. ADNP-deficient mice offer an ideal paradigm for evaluation of cognitive enhancers. NAP (NAPVSIPQ) is a peptide derived from ADNP that interacts with microtubules and provides potent neuroprotection. NAP treatment partially ameliorated cognitive deficits and reduced tau hyperphosphorylation in the ADNP(+/-) mice. NAP is currently in phase II clinical trials assessing effects on mild cognitive impairment.     

Nobiletin, a citrus flavonoid, improves memory impairment and Abeta pathology in a transgenic mouse model of Alzheimer's disease

Increasing evidence suggests that the elevation of beta-amyloid (Abeta) peptides in the brain is central to the pathogenesis of Alzheimer's disease (AD). Our recent studies have demonstrated that nobiletin, a polymethoxylated flavone from citrus peels, enhances cAMP/protein kinase A/extracellular signal-regulated kinase/cAMP response element-binding protein signaling in cultured hippocampal neurons and ameliorates Abeta-induced memory impairment in AD model rats. For the first time, we report that this natural compound improves memory deficits in amyloid precursor protein (APP) transgenic mice that overexpress human APP695 harboring the double Swedish and London mutations [APP-SL 7-5 transgenic (Tg) mice]. Our enzyme-linked immunosorbent assay (ELISA) also showed that administration of nobiletin to the transgenic mice for 4 months markedly reduced quantity of guanidine-soluble Abeta(1-40) and Abeta(1-42) in the brain. Furthermore, consistent with the results of ELISA, by immunohistochemistry with anti-Abeta antibody, it was evidently shown that the administration of nobiletin decreased the Abeta burden and plaques in the hippocampus of APP-SL 7-5 Tg mice. These findings suggest that this natural compound has potential to become a novel drug for fundamental treatment of AD.     

Expression of human apolipoprotein E reduces amyloid-beta deposition in a mouse model of Alzheimer's disease

The epsilon4 allele of apolipoprotein E (apo E) is associated with an increased risk for developing Alzheimer's disease (AD). This may be due to interactions between apo E and the amyloid-beta protein (Abeta). To assess the effects of human apo E isoforms on Abeta deposition in vivo, we bred apo E3 and apo E4 hemizygous (+/-) transgenic mice expressing apo E by astrocytes to mice homozygous (+/+) for a mutant amyloid precursor protein (APPV717F) transgene that develop age-dependent AD neuropathology. All mice were on a mouse apo E null (-/-) background. By nine months of age, APPV717F+/-, apo E-/- mice had developed Abeta deposition, and, as reported previously, the quantity of Abeta deposits was significantly less than that seen in APPV717F+/- mice expressing mouse apo E. In contrast to effects of mouse apo E, similar levels of human apo E3 and apo E4 markedly suppressed early Abeta deposition at nine months of age in APPV717F+/- transgenic mice, even when compared with mice lacking apo E. These findings suggest that human apo E isoforms decrease Abeta aggregation or increase Abeta clearance relative to an environment in which mouse apo E or no apo E is present. The results may have important implications for understanding mechanisms underlying the link between apo E and AD.     

认知功能测定在阿尔茨海默病中的应用

阿尔茨海默病(AD)是痴呆中最常见的类型,认知的定量测量一直在AD的诊断和研究中占有核心地位,能够反映患者认知功能受损的范围、程度,对AD的早期诊断、病情严重判断、疗效评定这三方面都具有重要作用。本文就认知功能测定在AD中的意义,常用的测定量表及相关问题作一阐述。     

AAV vector-mediated correction of brain pathology in a mouse model of Niemann-Pick A disease.

Niemann-Pick A disease (NPA) is a fatal lysosomal storage disorder caused by a deficiency in acid sphingomyelinase (ASM) activity. The lack of functional ASM results in cellular accumulation of sphingomyelin and cholesterol within distended lysosomes throughout the brain. In this study, we investigated the potential of AAV-mediated expression of ASM to correct the brain pathology in an ASM knockout (ASMKO) mouse model of NPA. An AAV serotype 2 vector encoding human ASM (AAV2-hASM) was injected directly into the adult ASMKO hippocampus of one hemisphere. This resulted in expression of human ASM in all major cell layers of the ipsilateral hippocampus for at least 15 weeks postinjection. Transduced cells were also present in the entorhinal cortex, medial septum, and contralateral hippocampus in a pattern consistent with retrograde axonal transport of AAV2. There was a substantial reduction of distended lysosomes and an almost complete reversal of cholesterol accumulation in all areas of the brain that were targeted by AAV2-hASM. These findings show that the ASMKO brain is responsive to ASM replacement and that retrograde transport of AAV2 functions as a platform for widespread gene delivery and reversal of pathology in affected brain.     

Memantine improves spatial learning in a transgenic mouse model of Alzheimer's disease

Memantine, a low- to moderate-affinity uncompetitive N-methyl-D-aspartate receptor antagonist, has been shown to improve learning and memory in several pharmacological models of Alzheimer's disease (AD). In the present study, the effect of memantine on locomotor activity, social behavior, and spatial learning was assessed in a transgenic mouse model of AD. Eight-month-old male C57BL/6J mice carrying mutated human APP and PS1 genes (APP/PS1) and their nontransgenic (NT) litter mates were administered a therapeutic dose of memantine (30 mg/kg/day p.o.) for 2 to 3 weeks. At this age, APP/PS1 mice show elevated levels of beta-amyloid peptides in several brain regions. APP/PS1 mice exhibited less exploratory rearing and increased aggressive behavior compared with NT mice. In the water maze test for spatial learning, APP/PS1 mice had longer escape latencies to both hidden and visible platforms, but they did not differ from NT mice in their swimming speed. Memantine significantly improved the acquisition of the water maze in APP/PS1 mice without affecting swimming speed. Memantine did not affect either locomotor activity or aggressive behavior in either genotype. These data indicate that memantine improves hippocampus-based spatial learning in a transgenic mouse model of AD without producing nonspecific effects on locomotion/exploratory activity.     

In vivo axonal transport rates decrease in a mouse model of Alzheimer's disease

Axonopathy is a pronounced attribute of many neurodegenerative diseases. In Alzheimer's disease (AD), axonal swellings and degeneration are prevalent and may contribute to the symptoms of AD senile dementia. Current limitations in identifying the contribution of axonal damage to AD include the inability to detect when this damage occurs in relation to other identifiers of AD because of the invasiveness of existing methods. To overcome this, we further developed the MRI methodology Manganese Enhanced MRI (MEMRI) to assess in vivo axonal transport rates. Prior to amyloid-beta (Abeta) deposition, the axonal transport rates in the Tg2576 mouse model of AD were normal. As Abeta levels increased and before plaque formation, we observed a significant decrease in axonal transport rates of the Tg2576 mice compared to controls. After plaque formation, the decline in the transport rate in the Tg2576 mice became even more pronounced. These data indicate that in vivo axonal transport rates decrease prior to plaque formation in the Tg2576 mouse model of AD.     

转基因阿尔茨海默病小鼠脑内炎症反应的诱发因素研究

目的 观察炎症反应在转基因阿尔茨海默病(AD)小鼠脑组织中的变化,探讨AD脑内炎症反应的诱发因素.方法 选用3、12个月龄转人β-淀粉样前体蛋白/早老素-1(APP/PS1)基因AD小鼠及正常野生型(WT)小鼠,分别应用免疫组织化学法和ELISA法观察脑内淀粉样斑块、炎性因子[白细胞介素(IL)-1β、IL-6、肿瘤坏死因子(TNF)α、前列腺素(PGE)2]的变化.结果 3个月龄APP/PS1基因AD小鼠脑组织中无淀粉样斑块沉积,未发现激活的星型胶质细胞和小胶质细胞,炎性因子IL-1β、IL-6、TNFα、PGE2的含量与WT小鼠差异无统计学意义(P均＞0.05).12个月龄转APP/PS1基因AD小鼠脑组织中有大量淀粉样斑块沉积,并伴有大量激活的星型胶质细胞和小胶质细胞,炎性因子IL-1β、IL-6、TNFα、PGE2的含量[分别为(56.02±9.04)、(8.66±0.83)、(97.48±26.58)、(72.18±21.01)ng/g]较WT小鼠[分别为(29.81±6.03)、(7.73±0.74)、(61.98±11.11)、(37.23±10.96)ng/g]及3个月龄转APP/PS1基因AD小鼠[分别为(30.05±3.53)、(7.43±1.17)、(59.34±10.47)、(42.56±5.93)ng/g]显著增加(P＜0.05或P＜0.01).结论 在淀粉样斑块形成之前,转APP/PS1基因AD小鼠脑组织中无明确的炎症反应;而淀粉样斑块沉积之后,脑组织中有显著的炎症反应;AD脑内炎症反应与淀粉样斑块形成密切相关,淀粉样蛋白(Aβ)沉积是导致脑内炎症反应的直接诱发因素.

Abstract：

Objective To observe the changes of cerebral inflammation-related markers in brain of a transgenic mouse model of Alzheimer's disease (AD) ,and to determine the causative factor to the development of cerebral inflammation in AD. Methods 3- and 12-month-old β-amyloid protein precursor ( APP)/presenilin (PSI) transgenic mice and age-matched wild-type mice (WT) were used in the study. The changes of amyloid plaques, inflammatory factors ( interleukin 1β ( IL-1β ); interleukin 6( IL-6 ); tumor necrosis factor α (TNFα) ;prostaglandin E2 (PGE2)) in the brains among these mice were measured by immunohistochemistry and ELISA. Results Immunohistochemical analysis revealed that no amyloid plaques and activated astrocytes as well as microglia were observed in the 3-month-old APP/PS1 mice. There were no significant differences in the levels of inflammatory factors (IL-1β, IL-6 ,TNFα,and PGE2) between the 3-month-old APP/PS1 and WT mice ( Ps ＞ 0. 05 ). However, abundant amyloid plaques accompanied by a remarkable increase of activated astrocytes and microglia were found in the brain of the 12-month-old APP/PS1 mice. The levels of inflammatory factors (IL-1β,IL-6,TNFα, and PGE2 ) were significantly increased in the 12-month-old APP/PS1 mice ([56. 02 ±9. 04] ng/g, [8. 66 ±0.83] ng/g, [97.48 ±26.58] ng/g, [72. 18 ±21.01] ng/g) than in the WT mice ([29. 18 ± 6. 03] ng/g, [7. 73 ± 0. 74] ng/g, [61.98 ±11.11] ng/g, [37. 23 ± 10. 96] ng/g) and the 3-month-old APP/PS1 mice ( [30. 05 ± 3.53] ng/g, [7.43 ± 1.17] ng/g, [59.34 ± 10. 07] ng/g, [42. 56 ±5.93] ng/g) (P＜0.05,or P＜0.01,respectively). Conclusion This study demonstrates that the APP/PS1mice did not show cerebral inflammation before the appearance of amyloid plaques, and exhibited remarkable inflammation after amyloid plaque deposition. These findings suggest that the induction of cerebral inflammation is tightly associated with amyloid plaque formation, and deposition of amyloid-beta protein (Aβ) may be the direct causative factor to the development of cerebral inflammation in AD.     

老年阿尔茨海默病患者认知功能与脑电图异常的关系

目的：探讨老年阿尔茨海默病患者认知功能与脑电图异常的关系。方法对41例老年阿尔茨海默病患者进行脑电图检测,并应用简易智力状态检查表、世界卫生组织‐加利福尼亚洛杉矶大学听觉词语学习测验、画钟测验进行测评分析。结果本组患者中重度痴呆12例,中度痴呆15例,轻度痴呆14例;脑电图轻度异常15例,中度异常14例,重度异常12例;不同程度脑电图异常患者简易智力状态检查表、世界卫生组织‐加利福尼亚洛杉矶大学听觉词语学习测验、画钟测验评分比较差异有极显著性（P＜0．01）,痴呆程度比较差异有显著性（P＜0．05）。结论脑电图可作为检测老年阿尔茨海默病患者认知功能的一个客观指标,脑电图检测联合神经心理学测验结果可作为阿尔茨海默病诊治的客观依据。     

慢性间断性缺氧对帕金森病模型小鼠认知功能的影响

目的：探讨慢性间断性缺氧（CIH）对帕金森病模型小鼠认知功能的影响。方法：44只雄性6周龄C57BL/6小鼠,随机分为百草枯组、CIH组、百草枯加CIH组和对照组。用缺氧-复氧循环装置模拟CIH过程,通过腹腔注射百草枯诱导制备帕金森病模型小鼠。使用Y型-电迷宫和跳台实验评价小鼠学习记忆能力;化学比色法测定小鼠海马乙酰胆碱含量和乙酰胆碱酯酶活性。结果：3个实验组的学习记忆成绩、乙酰胆碱含量和乙酰胆碱酯酶活性均明显低于对照组（P均〈0.01）,其中百草枯加CIH组明显低于百草枯组与CIH组（P均〈0.05）,百草枯组与CIH组比较差异无统计学意义（P均〉0.05）。结论：CIH加重了百草枯所致帕金森病模型小鼠认知功能下降程度,可能与海马Ach含量下降和Ach E活性降低有关。     

阿尔兹海默病小鼠不同时期脑血管的功能改变及机制

目的:研究散发性阿尔兹海默病(sAD)小鼠模型早期、中期脑血管功能改变及机制。方法:通过脑室内注射链脲霉素建立sAD模型,造模2周后采用Morris水迷宫评估小鼠认知功能,验证模型成立;利用活体成像技术检测假手术组、早期组(造模1周)、中期组(造模3个月)小鼠脑皮层动脉、穿支动脉、静脉及毛细血管对短暂高碳酸血症的血管反应性,并分别使用一氧化氮合酶抑制剂L-NAME及前列腺素合成抑制剂吲哚美辛阻断其相关通路,观察各组同种血管反应性变化。结果:与假手术组相比,造模2周后sAD小鼠学习、空间记忆能力显著下降。与假手术组相比,造模1周小鼠的脑皮层动脉、毛细血管的反应性均显著下降,皮层动脉反应性于造模3个月时恢复,而毛细血管反应性无明显恢复。LNAME可显著增加sAD小鼠脑动脉、毛细血管反应性。吲哚美辛可明显减弱sAD小鼠脑动脉反应性,但对毛细血管无影响。结论:sAD小鼠早期存在的脑血管功能损伤,可能参与认知障碍的发生和发展,其机制与一氧化氮通路改变有关。     

Longitudinal neuroanatomical changes determined by deformation-based morphometry in a mouse model of Alzheimer's disease

Magnetic resonance imaging (MRI) of transgenic mice has the potential to provide valuable insight into the complex mechanisms underlying Alzheimer's disease (AD). Quantification of pathological changes is typically performed using manual segmentation methods, and requires a priori hypotheses about anatomical structures for volumetric measurement. Alternatively, deformation-based morphometry (DBM) has been shown to be a powerful, automated technique for detecting anatomical differences between populations by examining the deformation fields used to nonlinearly warp MR images. In this multiple timepoint, in vivo study, we have applied an automated, unbiased technique for the creation of a nonlinear, population-specific reference space from which robust DBM analysis can be performed. A general, linear mixed-effects model framework was developed to follow the evolution of structural changes in mouse brain from 2.5 to 9 months of age, and to examine neuroanatomical differences between a transgenic (TG) APP/PS1 murine model of AD and wild-type (WT) littermates. Morphometric abnormalities in the TG group were localized to regions of the hippocampus, cortex, olfactory bulbs, stria terminalis, brain stem, cerebellum, and ventricles. Although volumetric reductions were detected in TG mice, no general brain atrophy was found, suggesting a developmental, rather than a degenerative, pathological process. Finally, we established a strong correlation between a DBM summary measure and manually segmented volumes for each image in the dataset. These results support the utility of DBM to study longitudinal morphological changes in mouse models of central nervous system diseases in an automated and exploratory fashion.     

阿尔茨海默病脑CT灌注与认知功能的相关性研究

目的:探讨阿尔茨海默病(AD)脑CT灌注与认知功能的相关性,评估CT灌注在AD病情评估中的应用价值。方法:根据临床诊断标准,51例AD采用飞利浦16排螺旋CT进行头颅平扫后再进行灌注扫描,随后在GEADW4.4工作站上作后处理,并进行灌注参数测量,灌注参数包括脑血容量(cerebral blood volume,CBV)、脑血流量(cerebral blood flow,CBF)、平均通过时间(mean transit time,MTT)和达峰时间(time to peak,TTP)。选择双侧颞叶皮质、双侧海马、双侧额叶皮质、双侧基底节豆状核区域进行测量,采用SPSS13.0统计软件进行统计分析,并将结果与简易智力状态检查(MMSE)评分行相关性分析。结果:单因素方差分析得出TTP与MMSE呈显著负相关(左额叶皮质P=0.031,左颞叶皮质P=0.008,右颞叶皮质P=0.024,左基底节P=0.009,右基底节P=0.019,右海马P=0.032,左海马P=0.009)。结论:脑CT灌注参数TTP与临床认知功能相结合对评估AD临床进展程度有一定帮助。     

NSAIDs prevent,but do not reverse,neuronal cell cycle reentry in a mouse model of Alzheimer disease

Ectopic cell cycle events (CCEs) mark vulnerable neuronal populations in human Alzheimer disease (AD) and are observed early in disease progression. In transgenic mouse models of AD, CCEs are found before the onset of β-amyloid peptide (Aβ) deposition to form senile plaques, a hallmark of AD. Here, we have demonstrated that alterations in brain microglia occur coincidently with the appearance of CCEs in the R1.40 transgenic mouse model of AD. Furthermore, promotion of inflammation with LPS at young ages in R1.40 mice induced the early appearance of neuronal CCEs, whereas treatment with 2 different nonsteroidal antiinflammatory drugs (NSAIDs) blocked neuronal CCEs and alterations in brain microglia without altering amyloid precursor protein (APP) processing and steady-state Aβ levels. In addition, NSAID treatment of older R1.40 animals prevented new neuronal CCEs, although it failed to reverse existing ones. Retrospective human epidemiological studies have identified long-term use of NSAIDs as protective against AD. Prospective clinical trials, however, have failed to demonstrate a similar benefit. Our use of CCEs as an outcome measure offers fresh insight into this discrepancy and provides important information for future clinical trials, as it suggests that NSAID use in human AD may need to be initiated as early as possible to prevent disease progression.     

CNI-1493 inhibits Abeta production, plaque formation, and cognitive deterioration in an animal model of Alzheimer's disease

Alzheimer's disease (AD) is characterized by neuronal atrophy caused by soluble amyloid beta protein (Abeta) peptide "oligomers" and a microglial-mediated inflammatory response elicited by extensive amyloid deposition in the brain. We show that CNI-1493, a tetravalent guanylhydrazone with established antiinflammatory properties, interferes with Abeta assembly and protects neuronal cells from the toxic effect of soluble Abeta oligomers. Administration of CNI-1493 to TgCRND8 mice overexpressing human amyloid precursor protein (APP) for a treatment period of 8 wk significantly reduced Abeta deposition. CNI-1493 treatment resulted in 70% reduction of amyloid plaque area in the cortex and 87% reduction in the hippocampus of these animals. Administration of CNI-1493 significantly improved memory performance in a cognition task compared with vehicle-treated mice. In vitro analysis of CNI-1493 on APP processing in an APP-overexpressing cell line revealed a significant dose-dependent decrease of total Abeta accumulation. This study indicates that the antiinflammatory agent CNI-1493 can ameliorate the pathophysiology and cognitive defects in a murine model of AD.     

Increased brain iron coincides with early plaque formation in a mouse model of Alzheimer's disease

Elevated brain iron content, which has been observed in late-stage human Alzheimer's disease, is a potential target for early diagnosis. However, the time course for iron accumulation is currently unclear. Using the PSAPP mouse model of amyloid plaque formation, we conducted a time course study of metal ion content and distribution [iron (Fe), copper (Cu), and zinc (Zn)] in the cortex and hippocampus using X-ray fluorescence microscopy (XFM). We found that iron in the cortex was 34% higher than age-matched controls at an early stage, corresponding to the commencement of plaque formation. The elevated iron was not associated with the amyloid plaques. Interestingly, none of the metal ions were elevated in the amyloid plaques until the latest time point (56 weeks), where only the Zn content was significantly elevated by 38%. Since neuropathological changes in human Alzheimer's disease are presumed to occur years before the first cognitive symptoms appear, quantification of brain iron content could be a powerful marker for early diagnosis of Alzheimer's disease.     

Peripheral transgene expression of plasma gelsolin reduces amyloid in transgenic mouse models of Alzheimer's disease.

The accumulation and deposition of the 40-42-amino acid peptide amyloid beta (Abeta) is thought to be a critical event in the pathology of Alzheimer's disease (AD). Both passive and active immunizations against Abeta in amyloid-depositing transgenic mice have reduced Abeta pathology and improved memory-related behavior. Peripheral treatments with other amyloid-binding agents have also reduced Abeta pathology. The present study demonstrates that peripheral delivery of plasmid DNA coding for the amyloid-binding protein plasma gelsolin reduces brain Abeta in two separate amyloid-depositing transgenic mouse models of AD when inter-litter variability is accounted for. The reduction in Abeta pathology observed is accompanied by an apparent increase in activated and reactive microglia and soluble oligomeric forms of amyloid. These findings demonstrate that peripheral expression of plasma gelsolin may be a suitable gene-therapeutic approach for the prevention or treatment of AD.     

Choline supplementation reduces oxidative stress in mouse model of allergic airway disease

Background  Asthma is a multi-factorial inflammatory disease associated with increased oxidative stress and altered antioxidant defences. We have evaluated the effect of choline on oxidative stress in a mouse model of airway disease.
Materials and methods  Balb/c mice were sensitised with 100 μg of ovalbumin on days 0 and 14, and challenged with aerosolized ovalbumin on days 25–27. Mice were administered 1 mg kg^–1 of choline via oral gavage or intranasal route on days 14–27. Mice were also administered 100 mg kg^–1 of α-lipoic acid as standard antioxidant. Total cell counts, eosinophils and eosinophil peroxidase (EPO) activity were determined in bronchoalveolar lavage (BAL) fluid. Reactive oxygen species (ROS), lipid peroxidation and isoprostanes levels were measured in BAL fluid. IL-13 and tumour necrosis factor-alpha (TNF-α) levels were also measured in BAL fluid and spleen cell culture supernatant. Nuclear factor κB (NFκB) p65 protein expression was measured after last ovalbumin challenge in nuclear and cytosolic extracts of lungs.
Results  Compared with ovalbumin-challenged mice, choline and α-lipoic acid treated mice had significantly reduced eosinophilic infiltration and EPO activity in BAL fluid. Choline and α-lipoic acid treatment reduced ROS production and isoprostanes level significantly in BAL fluid and thus suppressed oxidative stress. Choline and α-lipoic acid administration by either route decreased lipid peroxidation levels and down regulated NFκB activity. Further, choline and/or α-lipoic acid treatment suppressed TNF-α level significantly as compared with that of ovalbumin-challenged mice.
Conclusions  Choline administration reduces oxidative stress possibly by modulating the redox status of the cell and inhibits inflammatory response in a mouse model.