Arc/Arg3.1在糖尿病性脑病大鼠海马组织中的表达及其与认知功能改变的关系

目的：探讨糖尿病大鼠认知功能与海马Arc蛋白和β淀粉样蛋白（Aβ）表达的相关性,探讨突触可塑性在糖尿病性脑病（DE）发病机制中的作用。方法30只SPF级雄性8周龄大鼠随机分为对照组和糖尿病组,糖尿病组高脂饮食喂养4周后腹腔注射链脲佐菌素建立2型糖尿病大鼠模型,观察不同阶段动物的体质量、空腹血糖（FBG）、空腹血清胰岛素（FSI）,并计算胰岛素敏感指数（ISI）。实验末行水迷宫测试评估两组大鼠认知功能;酶联免疫吸附测定法、免疫组织化学法和蛋白质印迹法检测大鼠海马组织Aβ和Arc的表达。结果糖尿病组大鼠在目标象限的探索时间较对照组缩短（P＜0.01）,原平台穿越次数较对照组减少（P＜0.01）。糖尿病组Aβ表达较对照组升高（P＜0.01）,Arc/Arg3.1表达降低（P＜0.01）。结论糖尿病大鼠认知功能受损可能与Arc表达降低导致突触可塑性失衡加剧Aβ的沉积和神经元损伤有关。     

补肾益智方治疗阿尔茨海默病斑马鱼模型的作用及机制研究

目的 通过阿尔茨海默病斑马鱼模型,探讨补肾益智方的作用机制。方法 选取6月龄斑马鱼,随机分成5组,分为空白对照组（n=12）、模型组（n=10）、阳性药组（n=10）、补肾益智方高剂量组（n=11）和低剂量组（n=12）。除空白对照组,其余各组均用AlCl₃·6H₂O配制成浓度为100 μg/L的溶液持续浸泡斑马鱼30 d,每天更换一半的染毒培养液。染毒结束后利用T迷宫实验剔除染毒失败的斑马鱼。造模结束后,分别给予阳性药组多奈哌齐20 μg/mL,高、低剂量组补肾益智方30、10 μg/mL浸泡14 d。给药结束后,通过T迷宫实验检测斑马鱼学习记忆能力;免疫组化染色观察神经元变化;qPCR检测相关基因的表达;Western blot检测相关蛋白的表达。结果 ①在T迷宫测试第4天,模型组潜伏时间为（198.00±45.78）s,补肾益智方低剂量组为（12.75±2.29）s,补肾益智方高剂量组为（7.27±0.90）s,补肾益智方治疗组斑马鱼的潜伏时间明显低于模型组,差异有统计学意义（P<0.05）;②补肾益智方治疗组斑马鱼的端脑神经元数量较模型组明显增多、排列变整齐,星型胶质细胞增多;③补肾益智方组斑马鱼脑ACHE活力显著降低（P<0.01）、ChAT活力显著增加（P<0.05）;④补肾益智方治疗组斑马鱼脑组织中appb、bace1表达显著降低（P<0.01）,sod、cat、nrf2基因表达显著增加（P<0.01）,keap1基因表达显著降低（P<0.01）;⑤补肾益智方治疗组斑马鱼脑组织蛋白表达情况与qPCR结果一致,APP、BACE1表达显著降低（P<0.01）,Nrf2表达显著增加（P<0.01）,Keap1表达显著降低（P<0.01）。结论 补肾益智方能有效改善AD斑马鱼的学习记忆能力,减少Aβ生成,减轻氧化应激。      

Calcium-Sensing Receptors of Human Astrocyte-Neuron Teams: Amyloid-β-Driven Mediators and Therapeutic Targets of Alzheimer’s Disease

It is generally assumed that the neuropathology of sporadic (late-onset or nonfamilial) Alzheimer’s disease (AD) is driven by the overproduction and spreading of first Amyloid-β_x-42 (Aβ₄₂) and later hyperphosphorylated (hp)-Tau oligomeric “infectious seeds”. Hitherto, only neurons were held to make and spread both oligomer types; astrocytes would just remove debris. However, we have recently shown that exogenous fibrillar or soluble Aβ peptides specifically bind and activate the Ca²⁺-sensing receptors (CaSRs) of untransformed human cortical adult astrocytes and postnatal neurons cultured in vitro driving them to produce, accrue, and secrete surplus endogenous Aβ₄₂. While the Aβ-exposed neurons start dying, astrocytes survive and keep oversecreting Aβ₄₂, nitric oxide (NO), and vascular endothelial growth factor (VEGF)-A. Thus astrocytes help neurons’ demise. Moreover, we have found that a highly selective allosteric CaSR agonist (“calcimimetic”), NPS R-568, mimics the just mentioned neurotoxic actions triggered by Aβ●CaSR signaling. Contrariwise, and most important, NPS 2143, a highly selective allosteric CaSR antagonist (“calcilytic”), fully suppresses all the Aβ●CaSR signaling-driven noxious actions. Altogether our findings suggest that the progression of AD neuropathology is promoted by unceasingly repeating cycles of accruing exogenous Aβ₄₂ oligomers interacting with the CaSRs of swelling numbers of astrocyte-neuron teams thereby recruiting them to overrelease additional Aβ₄₂ oligomers, VEGF-A, and NO. Calcilytics would beneficially break such Aβ/CaSR-driven vicious cycles and hence halt or at least slow the otherwise unstoppable spreading of AD neuropathology     

Nasal mucosal inhalation of amyloid-beta peptide 3–10 defective adenovirus attenuates cytotoxicity induced by beta-amyloid(1–42)

Three-month-old Alzheimer's disease model transgenic mice were immunized with Aβ1–42, Plp-Adenovirus [Ad]-X-CMV-(Aβ3–10)10-CpG [AdCpG-(Aβ3–10)10] or AdCpG virus fluid via nasal mucosal inhalation, respectively. ELISA analysis of serum showed Aβ42 antibody titers were significantly increased in mice immunized with Aβ1–42 and AdCpG-(Aβ3–10)10. Concanavalin A and AdCpG-(Aβ3–10)10 stimulation significantly increased the number of proliferating spleen cells cultured from AdCpG(Aβ3–10)10 and Aβ42 groups compared with the control group. In the AdCpG(Aβ3–10)10 group, levels of interleukin(IL)-4 and IL-10 were increased, while those of IL-2 and interferon-γ were decreased. In the Aβ42 group, levels of IL-4, IL-10, IL-2 and interferon-γ were all increased. Experimental findings indicate that AdCpG-(Aβ3–10)10 vaccine can produce strong T helper 2(Th2) humoral immune responses in addition to the production of Aβ42 antibody. The cellular immunologic response was weak and avoided Aβ1–42-mediated cytotoxicity.     

APP/PS1双转基因小鼠早期记忆功能障碍与胆碱能系统的关系研究

目的观察转APP/PS1基因阿尔茨海默病小鼠(APP/PS1小鼠)早期空间学习记忆功能及乙酰胆碱能系统的变化以及两者之间的相关性,探讨阿尔茨海默病早期学习记忆障碍的发病机制。方法应用Morris水迷宫法评定3月龄APP/PS1小鼠及相应野生型(WT)小鼠的空间学习记忆功能;采用免疫组织化学及组织化学染色方法检测脑组织中β-淀粉样蛋白(Aβ)斑块沉积情况;采用ELISA法检测脑组织中乙酰胆碱(ACh)含量以及胆碱乙酰转移酶(ChAT)和乙酰胆碱酯酶(AChE)活性,并探讨小鼠脑组织中ACh含量与其空间记忆能力、ChAT活性的相关性。结果水迷宫评定结果显示两组小鼠到达平台的潜伏期无统计学差异(P>0.05);APP/PS1小鼠在目标象限的游泳时间百分比〔(29.02±4.27)%〕和距离百分比〔(28.85±3.77)%〕较WT小鼠均下降(P<0.05)。APP/PS1小鼠脑组织中尚无Aβ斑块的沉积。APP/PS1小鼠脑组织中ACh含量〔(45.23±1.40)ng/g prot〕和ChAT活性〔(279.53±12.13)U/g组织湿重〕均较WT小鼠〔分别为(54.08±4.84)ng/gprot、(315.84±11.32)U/g组织湿重〕显著降低(P<0.05),两组小鼠脑组织中AChE活性无统计学差异(P>0.05)。小鼠脑组织中ACh含量与其空间记忆功能(目标象限航行时间百分比、目标象限航行路程百分比)呈正相关(r=0.861、r=0.874,P<0.05),ACh含量与ChAT活性呈正相关(r=0.926,P<0.05)。结论 APP/PS1小鼠空间记忆功能障碍、ACh含量减少和ChAT活性降低可发生于Aβ斑块沉积之前。脑组织中ACh含量减少和ChAT活性降低可能与APP/PS1小鼠记忆功能损害密切相关。     

CSF-tau,CSF-Aß1-42, ApoE-genotype and clinical parameters in the diagnosis of Alzheimer’s disease: combination of CSF-tau and MMSE yields highest sensitivity and specificity

Summary. This study evaluated the sensitivity and specificity of the cerebrospinal fluid (CSF) levels of tau-protein, amyloid-ß-peptide 1-42 (Aß1-42), ApoE-genotype and the degree of cognitive decline as diagnostic markers for Alzheimers disease (AD). Data was obtained from 105 AD patients and 68 controls.Median CSF-tau levels were increased (512pg/ml vs. 145pg/ml, p<0.001) and Aß1-42-levels were decreased (238.5pg/ml vs. 310pg/ml, p<0.001) in AD patients compared to controls. A weak correlation was found between CSF-Aß1-42 and MMSE score (r=.245). Within all subjects, a correlation of CSF-Aß1-42 (r=–.337) and CSF-tau (r=.384) with age was found. The combination of CSF-tau levels and MMSE revealed the highest sensitivity (92%) and specificity (87%).In summary, CSF-tau was a useful biological marker to discriminate AD from normal aging, neurological and psychiatric disorders. CSF-Aß1-42 showed no additional benefit in discriminating patients from controls but might be useful for tracking the severity of the disease.Received January 20, 2003; accepted April 29, 2003 Published online July 30, 2003     

The miR-124 regulates the expression of BACE1/β-secretase correlated with cell death in Alzheimer's disease

The role of miR-124 on the expression of β-site APP cleaving enzyme 1 (BACE1), an important cleavager of amyloid precursor protein that plays a pivotal role in the β-amyloid production, was studied in this paper using cellular models for Alzheimer’ disease (AD) of cultured PC12 cell lines and primary cultured hippocampal neurons. The aim of the present study was to uncover novel potential miR-124 targets and shed light on its function in the cellular AD model. MiR-124 expression was steadily altered when its mimic and inhibitor were transfected in vitro. The results showed the expression of BACE1, one of the potential functional downstream targets of miR-124, was well correlated with cell death induced by Aβ neurotoxicity, and its expression level could be up- and down-regulated by suppression or over expression of miR-124 level respectively. These findings suggest that miR-124 may work as a basilic regulating factor to alleviate cell death in the process of AD by targeting BACE1, play an essential role in the control of BACE1 gene expression, and might be considered as a novel therapeutic target in treating AD.     

Aβ_(20-29)短肽阻断ApoE/Aβ结合并减少Aβ_(1-42)纤维化及其神经毒性的效应作用

目的:探讨β-淀粉样蛋白(Aβ)20-29(Aβ_(20-29))短肽在阻断载脂蛋白E(ApoE)4与Aβ_(1-42)相结合并减少Aβ_(1-42)纤维化及其神经毒性中的效应作用。方法:应用硫磺素-T(Th-T)荧光分析和透射电镜方法,观察Aβ_(20-29)短肽阻断ApoE与Aβ_(1-42)相结合及其防止Aβ_(1-42)纤维化的效应作用;应用培养的PC12细胞,观察Aβ_(20-29)短肽对ApoE4+Aβ_(1-42)神经毒性的效应作用。结果:荧光分析和透射电镜观察显示:Aβ_(20-29)短肽不能形成纤维性Aβ,ApoE4对Aβ_(1-42)纤维化具有显著促进作用,Aβ_(20-29)短肽能够显著减少ApoE4对Aβ_(1-42)纤维化的促进作用,且呈剂量依赖关系。应用培养的PC12细胞及MTT法测定细胞活性,表明Aβ_(20-29)短肽对PC12细胞无神经毒性作用,其能够显著减少ApoE4+Aβ_(1-42)的神经毒性作用。结论:Aβ_(20-29)短肽在体外能够有效抑制ApoE4与Aβ_(1-42)相结合,并显著减少Aβ_(1-42)纤维化及其神经毒性作用,提示Aβ_(20-29)短肽有可能成...     

黄芩茎叶总黄酮对AD大鼠海马神经元的保护作用及机制研究

目的：探讨黄芩茎叶总黄酮(SSTF)对大鼠双侧海马注射Aβ25－35引起的大鼠学习记忆功能和海马神经元形态变化的影响及机制。方法：将30只雄性Wistar大鼠随机分为对照组、模型组、总黄酮组,对照组及模型组灌胃纯化水,qd,d 8对照组海马注射生理盐水,继续灌胃;模型组双侧海马注射Aβ25－35（5 μL）,其他同对照组;给药组总黄酮（50 mg?kg-1,ig,qd),d 8海马注射Aβ,继续灌胃,三组于d 15采用Morris水迷宫实验观察大鼠学习记忆能力,测5 d,处死,硫堇Nissl染色观察海马神经元的变化,检测血清中丙二醛（MDA）含量。结果：模型组大鼠逃避潜伏期较对照组明显延长（P<0.05）,给药组大鼠逃避潜伏期较模型组明显缩短（P<0.05）;模型组海马CA1区局部神经细胞带脱失,脱失处胶质细胞增多,给药组细胞损伤较轻;模型组大鼠血清中MDA显著高于对照组（P<0.05）,给药组血清中MDA明显低于模型组（P<0.05）。结论：黄芩茎叶总黄酮对海马注射Aβ25－35引起大鼠学习记忆能力降低及海马神经元形态变化具有保护作用,其机制可能是减少Aβ引起的脂质过氧化产物增多引起的氧化应激,并可对抗Aβ引起的胶质细胞增多。     

白藜芦醇通过SIRT1激活ADAM10促进APPα代谢

目的：探讨白藜芦醇可否通过SIRT1激活解整合素金属蛋白酶10（ADAM10）促进APPα代谢抑制Aβ分泌。方法：选取过表达人瑞典突变淀粉样前体蛋白APP695sw的细胞模型,分别设立DMSO空白对照组、SIRT1激活剂白藜芦醇组和SIRT1抑制剂EX527组。给药后,ELISA法分别检测细胞培养上清中sAPPα和Aβ的含量,免疫印记Western Blot法检测细胞SIRT1和ADAM10的蛋白水平。结果：与对照组比较,白藜芦醇组细胞培养上清sAPPα的含量增高,Aβ含量下降,sAPPα/Aβ比值增大,细胞SIRT1和ADAM10蛋白水平增高;而抑制剂EX527组与对照相比,细胞培养上清sAPPα的含量降低,Aβ含量升高,sAPPα/Aβ比值减小,细胞SIRT1和ADAM10蛋白水平降低;抑制剂下调SIRT1后各项指标与激动剂组呈现相反的趋势（P<0.05）。结论：白藜芦醇可通过SIRT1激活ADAM10,促进APP进行α非淀粉样代谢途径,增强sAPPα分泌并抑制Aβ产生。