Gamma-glutamyl transferase 5 overexpression in cerebrovascular endothelial cells improves brain pathology,cognition,and behavior in APP/PS1 mice

In patients with Alzheimer’s disease,gamma-glutamyl transferase 5(GGT5)expression has been observed to be downregulated in cerebrovascular endothelial cells.However,the functional role of GGT5 in the development of Alzheimer’s disease remains unclear.This study aimed to explore the effect of GGT5 on cognitive function and brain pathology in an APP/PS1 mouse model of Alzheimer’s disease,as well as the underlying mechanism.We observed a significant reduction in GGT5 expression in two in vitro models of Alzheimer’s disease(Aβ_(1-42)-treated hCMEC/D3 and bEnd.3 cells),as well as in the APP/PS1 mouse model.Additionally,injection of APP/PS1 mice with an adeno-associated virus encoding GGT5 enhanced hippocampal synaptic plasticity and mitigated cognitive deficits.Interestingly,increasing GGT5 expression in cerebrovascular endothelial cells reduced levels of both soluble and insoluble amyloid-βin the brains of APP/PS1 mice.This effect may be attributable to inhibition of the expression ofβ-site APP cleaving enzyme 1,which is mediated by nuclear factor-kappa B.Our findings demonstrate that GGT5 expression in cerebrovascular endothelial cells is inversely associated with Alzheimer’s disease pathogenesis,and that GGT5 upregulation mitigates cognitive deficits in APP/PS1 mice.These findings suggest that GGT5 expression in cerebrovascular endothelial cells is a potential therapeutic target and biomarker for Alzheimer’s disease.

AAV mediated carboxyl terminus of Hsp70 interacting protein overexpression mitigates the cognitive and pathological phenotypes of APP/PS1 mice

The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease.We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain.CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests,reduced amyloid-βplaques,and decreased the expression of both amyloid-βand phosphorylated tau.CHIP also alleviated the concentration of microglia and astrocytes around plaques.In APP/PS1 mice of a younger age,CHIP overexpression promoted an increase in ADAM10 expression and inhibitedβ-site APP cleaving enzyme 1,insulin degrading enzyme,and neprilysin expression.Levels of HSP70 and HSP40,which have functional relevance to CHIP,were also increased.Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated,which may also reflect a potential mechanism for the neuroprotective effect of CHIP.Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice.Indeed,overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.

陈皮提取物对APP/PS-1双转基因阿尔茨海默病小鼠学习记忆功能的影响

目的探讨陈皮提取物对APP/PS-1双转基因阿尔茨海默病(AD)小鼠学习记忆功能的影响.方法选用APP/PS-1双转基因AD小鼠16只,随机分为模型对照组和供试品组,8只/组,另取8只C57小鼠为正常对照组,正常对照组和模型对照组分别灌胃等量的生理盐水,供试品组灌胃陈皮提取物的生理盐水溶解液,灌胃体积为10mL/kg,1次/d,连续18d.第11天到第16天,进行Morris水迷宫的定位航行实验及空间探索实验.第17天到第18天,进行5min避暗实验.结果在Morris水迷宫实验中,与正常对照组比较,模型对照组定位航行第2天、第3天、第5天的潜伏期增加(P<0.05);与模型对照组比较,供试品组第5天的潜伏期降低(P<0.05).空间探索阶段,各组的目标象限路程百分比、时间百分比及站台穿越次数差异无统计学意义(P>0.05).在避暗实验中各组的错误潜伏期、错误次数及错误率差异均无统计学意义(P>0.05).结论陈皮提取物对APP/PS-1双转基因AD小鼠的空间学习、记忆能力有一定的改善作用.

Ketogenic diet alleviates cognitive dysfunction and neuroinflammation in APP/PS1 mice via the Nrf2/HO-1 and NF-κB signaling pathways

Alzheimer's disease is a progressive neurological disorder characterized by cognitive decline and chronic inflammation within the brain.The ketogenic diet,a widely recognized therapeutic intervention for refractory epilepsy,has recently been proposed as a potential treatment for a variety of neurological diseases,including Alzheimer's disease.However,the efficacy of ketogenic diet in treating Alzheimer's disease and the underlying mechanism remains unclear.The current investigation aimed to explore the effect of ketogenic diet on cognitive function and the underlying biological mechanisms in a mouse model of Alzheimer's disease.Male amyloid precursor protein/presenilin 1(APP/PS1)mice were randomly assigned to either a ketogenic diet or control diet group,and received their respective diets for a duration of 3 months.The findings show that ketogenic diet administration enhanced cognitive function,attenuated amyloid plaque formation and proinflammatory cytokine levels in APP/PS1 mice,and augmented the nuclear factor-erythroid 2-p45 derived factor 2/heme oxygenase-1 signaling pathway while suppressing the nuclear factor-kappa B pathway.Collectively,these data suggest that ketogenic diet may have a therapeutic potential in treating Alzheimer's disease by ameliorating the neurotoxicity associated with Aβ-induced inflammation.This study highlights the urgent need for further research into the use of ketogenic diet as a potential therapy for Alzheimer's disease.

Tetrahydroxy Stilbene Glucoside Ameliorates Cognitive Impairments and Pathology in APP/PS1 Transgenic Mice

Cognitive impairment is the main clinical manifestation of Alzheimer's disease(AD),and amyloid-β(AB)deposition and senile plaques are the characteristic neuropathological hallmarks in AD brains.This study aimed to explore the effect and mechanism of tetrahydroxy stilbene glucoside(TSG)on cognitive function in APP/PS 1 mice during long-term administration.Here,we treated APP/PS1 model mice of AD with different doses of TSG(50 mg/kg and 100 mg/kg)for 5 to 17 months by gavage,and we further observed whether TSG could ameliorate the cognitive decline in APP/PS1 mice using behavioral tests,and investigated the possible mechanisms by immunohistochemistry and Western blotting.Our results showed that TSG treatment rescued the spatial and non-spatial learning and memory impairments of APP/PS1 mice at Morris water maze test and novel object recognition test.Furthermore,Aβ40/42 deposition in the cortex and hippocampus of APP/PS1 mice treated with TSG was significantly reduced compared to the wild type mice using the immunohistochemical technique.Finally,Western blotting showed that TSG primarily decreased the APP expression to avoid the Aβplaque deposition in the cortex and hippocampus of mice.These results reveal the beneficial effects of TSG in APP/PSI-AD mice,which may be associated with the reduction of Aβdeposits in the brain.

NP-12 The Phosphodiesterase-4 Inhibitor Roflumilast Reverses Cognition Deficits and Depression-Like Effects via cAMP Signaling-Mediated Neuroprotection in APP/PS1 Transgenic Mice

Phosphodiesterase-4(PDE4)has been demonstrated to be a promising target for treatment of Alzheimer’s disease(AD).Roflumilast(Rof),a potent PDE4 inhibitor,has been approved for treatment of chronic obstructive pulmonary disease(COPD)in humans.Recent studies have shown that Rof improves cognition at doses that do not cause an emetic response,the major side-effect of PDE4 inhibitors.However,the effect of Rof on cognition associated with AD remains largely unknown.Here we examined the effects of Rof on behavioral dysfunction and the related mechanisms in APP/PS1 double transgenic mice,a widely used model for AD.Mice at 10 months of age were first tested in novel object recognition for memory.The recognition index in APP/PS1 mice was decreased compared to WT mice,which was reversed by Rof at 5 and 10 mg·kg-1.This was then verified in the Morris water-maze test.The escape latency during acquisition training was significantly longer and the entries into the target quadrant during the probe trial were much less compared to WT controls,these were also reversed by Rof.In the tail-suspension and forced-swimming tests,which measure depression-like behavior,APP/PS1 mice showed prolonged immobility time,which was reversed by Rof.In addition,the staining of HE and Nissl showed that Rof reduced the loss of neurons and neurocyte apoptosis in APP/PS1 mice.It also reversed the decreased ratio of Bcl-2/BAX and inhibited the increased expression of PDE4D in the cerebral cortex and hippocampus of APP/PS1 mice.Finally,Rof reversed the decreased levels of cAMP and expression of phosphorylated cAMP response element-binding protein(CREB)and brain derived neurotrophic factor(BDNF)in APP/PS1 mice.Overall,these results suggest that Rof not only improves learning and memory,but attenuates depression-like behavior in AD mice,likely via PDE4D/cAMP/CREB/BDNF signaling-mediated neuroprotection.Therefore,Rof can be a therapeutic agent for AD,in particular the comorbidity of memory deficits and depression.

紫云英苷抑制APP/PS 1小鼠大脑皮质神经元凋亡

【目的】探讨紫云英苷(AST)对APP/PS1转基因小鼠大脑皮质神经元凋亡的影响。【方法】将18只6月龄雄性APP/PS1转基因小鼠随机分为APP/PS1、APP/PS1+40 mg/kg AST、APP/PS1+20 mg/kg DNP(Donepezil,DNP)三组,每组各6只动物。同时另选6只同月龄C57BL/6雄性小鼠作为正常对照组(Control)。腹腔注射给药AST,每日一次,连续给药一个月后,Tunel染色法检测APP/PS1小鼠大脑皮质内神经元凋亡情况;免疫荧光染色法检测APP/PS1小鼠大脑皮质内神经元凋亡相关蛋白Bax、Bcl-2、Caspase9、Cleaved-Caspase3表达情况;Western blot法检测APP/PS1小鼠大脑皮质内Bax、Bcl-2、Caspase9及Caspase3表达水平的变化。【结果】Tunel染色结果显示,40 mg/kg AST及20 mg/kg DNP均可减少APP/PS1小鼠大脑皮质内神经元凋亡,其中AST抑制效果尤为明显。免疫荧光染色结果表明,40 mg/kg AST及20 mg/kg DNP均抑制APP/PS1小鼠大脑皮质内神经元中Bax、Caspase9及Cleaved-Cas⁃pase3的表达,增加Bcl-2的表达。Western blot结果进一步证实,40 mg/kg AST及20 mg/kg DNP均可下调APP/PS1小鼠大脑皮质内神经元Bax(P<0.05,P<0.05)、Caspase9(P<0.005,P<0.05)及Caspase3(P<0.0001,P<0.0001),上调Bcl-2(P<0.05,P<0.05)。【结论】AST能够抑制APP/PS1小鼠大脑皮质神经元凋亡。

琐琐葡萄黄酮对APP/PS-1双转基因阿尔茨海默病小鼠神经炎症的保护作用

目的研究琐琐葡萄黄酮(VTF)对APP/PS-1双转基因阿尔茨海默病(AD)小鼠神经炎症保护作用的机制。方法选取6月龄APP/PS-1双转基因雄性小鼠75只,随机分为模型组(0.5%CMC-Na)、阳性组(多奈哌齐0.7 mg/kg体重)、VTF低剂量组(VTF 70 mg/kg体重)、VTF中剂量组(VTF 210 mg/kg体重)、VTF高剂量组(VTF 420 mg/kg体重),每组15只;另选取6月龄同背景SPF级C57BL/6小鼠15只为对照组(0.5%CMC-Na)。灌胃8周后,免疫组织化学检测IBA1蛋白表达;Western blotting检测APP、IBA1蛋白表达;酶联免疫吸附试验(ELISA)检测脑组织的白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)的含量。结果对照组、阳性组及VTF各剂量组IBA1蛋白阳性表达率较模型组低(P<0.05);对照组、阳性组及VTF各剂量组APP、IBA1蛋白相对表达量较模型组低(P<0.05);对照组、阳性组及VTF各剂量组IL-1β、IL-6、TNF-α含量较模型组减少(P<0.05)。结论VTF可以减少APP/PS-1双转基因AD小鼠神经炎症的发生,并通过下调APP、IBA1蛋白的表达发挥神经保护作用。

Distinct effect of potassium 2-(l-hydroxypentyl) - benzoate on hippocampal neurons, synapses and dystrophic axons in APP/PS1 mice

OBJECTIVE To study the protective effect of potassium 2-(l-hydroxypentyl)-benzoate(PHPB) on hippocampal neurons,synapses and dystrophic axons in APP/PS1 mice.METHODS Ten-month-old male APP/PS1 transgenic mice and age-matched wild-type mice were randomly divided into three groups:wild-type group(WT Con group,n=10),APP/PS1 group(Tg Con group,n=10) and PHPB treated APP/PS1 group(PHPB group,n=10).PHPB group received 30 mg · kg-1 PHPB by oral gavage once daily for 3 months.WT Con group and Tg Con group received the same volume of water.Three months later,mice were sacrificed for biochemical and pathological testing such as transmission electron microscopy,Golgi staining and Western boltting analysis.RESULTS Under the transmission electron microscope,most hippocampal neurons and subcel ular organel es in WT Con group exhibited normal morphology.However,the degenerative changes were observed in Tg Con group such as nuclear fragmentation,mitochondrial swelling,ribosomes detachment and autophagic vacuoles accumulation.The hippocampal synapses number and the thickness of postsynaptic density(PSD) were significantly decreased in Tg Con group compared with the WT Con group(P<0.05).After PHPB treatment,the degenerative changes in APP/PS1 mice were alleviated to some extent.The synapse number has been elevated significantly(P<0.05) and the PSD has been thickened as well.Golgi staining showed that the spine density of secondary and tertiary apical dendritic branches was significantly decreased in CA1 and DG areas of Tg Con group(P<0.05).Sholl analysis revealed a decrease of dendritic complexity in Tg Con group compared with WT Con group(P<0.05).These abnormalities were alleviated to some extent after PHPB treatment.Western blotting study showed that the protein levels of synaptic marker PSD-95 and synaptophysin were significantly decreased in the hippocampus of Tg Con group(P<0.05).A significant increase of PSD-95(P<0.05) and a slight increase of SYP were observed after the PHPB treatment.Besides,we found a significant increase in the ratio of LC3-Ⅱ/LC3-Ⅰ in Tg Con group compared with the WT Con group(P<0.01) and the relevant improvement after PHPB treatment(P<0.05),which showed the regulatory effect of PHPB on autophagy impairment.CONCLUSION PHPB showed protective effects on hippocampal neurons,synapses and dystrophic axons in APP/PS1 mice,which might help explain its role on cognitive improvement in Alzheimer disease treatment.

有氧运动对APP/PS1小鼠大脑皮质和海马组织Keap1/Nrf2信号通路的影响

目的:探讨有氧运动对APP/PS1小鼠大脑皮质和海马组织Keap1/Nrf2信号通路的影响,为揭示有氧运动防治阿尔兹海默症提供理论基础。方法:雄性APP/PS1小鼠随机分为安静对照组(CG)和运动组(EG)。EG组小鼠进行为期8周的跑台训练,速度从12 m/min增至15 m/min,训练时间从30 min增至60 min。最后一次训练结束后48小时,分离所有小鼠大脑皮质和海马组织。通过荧光定量PCR和West-ern blot检测各组小鼠大脑皮质和海马组织中结构蛋白Keap1、Nrf2和Maf及下游抗氧化蛋白HO-1、NQO1和GCLC的mRNA及蛋白含量;通过Western blot检测APP、Aβ42和BACE1的蛋白含量;通过试剂盒检测MDA和GSH含量及GSH-Px和T-SOD活力。结果:8周跑台训练后,EG组小鼠大脑皮质和海马组织Keap1 mRNA和蛋白含量与CG组相比无显著性差异,而Nrf2和Maf mRNA和蛋白含量均显著高于CG组;EG组HO-1、NQO1和GCLC mRNA和蛋白含量均显著高于CG组;EG组MDA含量显著低于CG组,而GSH含量、GSH-Px和T-SOD活力显著高于CG组;APP蛋白含量与CG组相比未发生显著改变,但Aβ42和BACE1的蛋白含量显著低于CG组。结论:有氧运动增强APP/PS1小鼠大脑皮质和海马组织中Keap1/Nrf2信号通路活性;提高该通路下游抗氧化蛋白HO-1、NQO1和GCLC的含量;降低大脑皮质和海马组织氧化应激水平;从而有效抑制Aβ蛋白的形成。

小续命汤对APP/PS1转基因鼠海马区Aβ、GFAP蛋白的影响及其行为学分析

目的:观察小续命汤对APP/PS1转基因鼠海马区Aβ及GFAP蛋白的影响,探讨小续命汤改善认知功能障碍的作用机制。方法:采用APP/PS1双转基因小鼠建立阿尔茨海默病模型,将同月龄的同窝阴性鼠作为空白对照组,按照随机数字表将基因鼠分为模型组和小续命汤组,模型组和空白对照组不给药,小续命汤组按照13 g/kg连续灌胃90 d。Morris水迷宫法检测小鼠学习记忆能力,免疫组化染色观察3组小鼠大脑海马区Aβ、GFAP蛋白的表达。结果:与模型组比较,小续命汤组在水迷宫空间探索实验中,到达目标区域的时间及搜索距离明显缩短(P<0.05),穿梭次数明显增多(P<0.05);免疫组化结果显示:与空白对照组比较,模型组小鼠大脑海马区Aβ阳性蛋白及GFAP阳性细胞均明显增加(P<0.01);与模型组比较,小续命汤组Aβ蛋白的沉积及GFAP阳性细胞均明显减少(P<0.05)。结论:小续命汤改善APP/PS1基因鼠的认知功能可能与减少大脑海马区Aβ沉积、降低星形胶质细胞的活化有关。

中链脂肪酸联合α-亚麻酸对APP/PS1转基因小鼠学习记忆行为及大脑Aβ42、Tau蛋白表达的影响

目的探讨中链脂肪酸(medium-chain fatty acid,MCFA)和α-亚麻酸(α-linolenic acid,ALA)对APP/PS1转基因小鼠学习记忆功能及大脑Aβ42、Tau蛋白表达的影响。方法将25只4周龄APP/PS1转基因小鼠随机分为ALA+MCFA组(8只)、MCFA组(9只)和长链脂肪酸(long chain fatty acid,LCFA)组(8只,对照组),同窝野生型小鼠为WT组(10只,正常对照组)。各组小鼠用不同脂肪酸配制饲料连续喂养至36周龄,用Morris水迷宫进行定位航行实验和空间探索实验,并记录平均逃避潜伏期、平台穿越次数和平台象限滞留时间百分比。免疫组化法检测海马Aβ沉积,Western blot方法检测APP、Aβ42蛋白及Tau蛋白表达。结果与LCFA组小鼠相比,ALA+MCFA组和MCFA组小鼠水迷宫定位航行试验平均逃避潜伏期明显缩短(P<0.05),空间探索试验平台穿越次数则明显较高(P<0.05),海马组织Aβ斑块数目相对较少,且皮质和海马Aβ42蛋白及Tau蛋白表达均较低(P<0.05)。结论与LCFA相比,ALA和MCFA能通过减少Aβ42蛋白生成及Tau蛋白磷酸化水平,改善APP/PS1转基因小鼠学习记忆功能,具有潜在的延缓阿尔茨海默病发生和进展的作用。

APPswe／PS1dE9转基因小鼠繁殖性能及生长发育观察

目的为建立阿尔茨海默病APPswe／PS1dE9转基因小鼠生物学特性标准化资料提供实验依据。方法APPswe／PS1dE9转基因小鼠杂合子交配繁殖，建立基因型鉴定方法，选择160窝次的1158只小鼠分别统计4胎内不同胎次、不同基因型的繁殖性能及生长发育指标。结果①APP／Ps1片段大小为600bp；②第2胎和第3胎的仔鼠数量及阳性数量均大于第1胎（P〈0．05），阳性率则无明显差异（P〉0．05）；③第1、2胎之间的胎间隔天数较短（P〈0．05），第2、3胎的窝产仔数、离乳仔数及离乳率均高于其它两胎（P〈0．05）；④第3胎和第4胎的初生窝重、泌乳力和离乳个体重较为稳定；⑤雌雄APP／PS1小鼠的最高体重分别为24．45±0．92g和30．21士2．53g；⑥该转基因小鼠的基因型不影响其体重（P〉O．05）。结论建立了APP／PS1小鼠的基础生物学特性资料；

EGCG改善APP/PS1转基因小鼠认知功能及减轻海马胰岛素抵抗的机制研究

目的探讨EGCG没食子酸酯(epigaliocatechin—3—gallate,EGCG)减轻APP/PSl转基因小鼠海马胰岛素抵抗并改善认知功能机制。方法 24只12月龄雌性APP/PSl小鼠随机均分为模型组(Tg)、EGCG低剂量组(Tg/EGCG—L)、高剂量组(Tg/EGCG—H),同月龄雌性C 57 BL/6 J小鼠作为对照组(NT)。采用Morris水迷宫检测各组小鼠学习、记忆能力,Western blot和免疫组织化学方法检测各组小鼠海马TNF—α/JNK信号及IRS—1 pSer 312的表达。结果与NT组比较,Tg组小鼠寻找平台的逃避潜伏期及平均路程显著延长(P<0.05),海马TNF—α/JNK信号异常活化、IRS—1 pSer312表达明显升高(P<0.05).EGCG各治疗组较Tg组各异常指标均显著改善(P<0.05)。结论 EGCG可减轻APP/PS1转基因小鼠海马胰岛素抵抗,改善认知功能,其机制可能与其降低TNF—α/JNK信号通路的活化相关。

琐琐葡萄黄酮对APP/PS-1双转基因AD小鼠的作用研究

目的 探讨琐琐葡萄黄酮(flavones from Vitis vinifera L.,VTF)对APP/PS-1双转基因AD小鼠神经保护作用研究。方法 选用6月龄雄性APP/PS-1双转基因AD小鼠75只,随机分为模型组、阳性对照组(多奈哌齐组,0.7mg/kg)和琐琐葡萄总黄酮(VTF)低、中、高剂量组(70、210、420mg/kg),另取15只同龄雄性C57BL/6小鼠为空白对照组,模型组和空白对照组给予等量0.5%CMC-Na灌胃,8周后采用Morris水迷宫观察小鼠空间认知能力,应用HE染色和免疫组化学染色(IHC)观察小鼠海马CA1区神经元细胞形态以及APP和Aβ_(1~42)蛋白表达情况。结果 与空白对照组比较,模型组小鼠逃逸潜伏期显著延长(P<0.01),有效区域进入次数显著减少(P<0.01);与模型组比较,VTF各剂量组逃逸潜伏期显著缩短(P<0.05),VTF低和中剂量有效区域进入次数显著增多(P<0.05)。镜下观察结果显示,与空白对照组比较,模型组存在大量呈凋亡趋势的神经元细胞,排列不规则,胞质萎缩出现间隙,CA1区APP和Aβ_(1~42)蛋白表达量增加;阳性对照组及VTF各剂量组海马神经元大多数较正常,排列较规整紧密,核仁清晰,核固缩浓染减轻,APP和Aβ_(1~42)蛋白表达量减少。结论 VTF可改善APP/PS-1双转基因AD小鼠学习记忆能力,对小鼠大脑神经元细胞有良好的保护作用,可减少APP和Aβ_(1~42)在小鼠脑内的过表达,对APP/PS-1双转基因AD小鼠具有较好的防治作用。

Longitudinal assessment of peripheral organ metabolism and the gut microbiota in an APP/PS1 transgenic mouse model of Alzheimer’s disease

Alzheimer’s disease not only affects the brain,but also induces metabolic dysfunction in peripheral organs and alters the gut microbiota.The aim of this study was to investigate systemic changes that occur in Alzheimer’s disease,in particular the association between changes in peripheral organ metabolism,changes in gut microbial composition,and Alzheimer’s disease development.To do this,we analyzed peripheral organ metabolism and the gut microbiota in amyloid precursor protein-presenilin 1(APP/PS1)transgenic and control mice at 3,6,9,and 12 months of age.Twelve-month-old APP/PS1 mice exhibited cognitive impairment,Alzheimer’s disease-related brain changes,distinctive metabolic disturbances in peripheral organs and fecal samples(as detected by untargeted metabolomics sequencing),and substantial changes in gut microbial composition compared with younger APP/PS1 mice.Notably,a strong correlation emerged between the gut microbiota and kidney metabolism in APP/PS1 mice.These findings suggest that alterations in peripheral organ metabolism and the gut microbiota are closely related to Alzheimer’s disease development,indicating potential new directions for therapeutic strategies.

Lamotrigine protects against cognitive deficits,synapse and nerve cell damage,and hallmark neuropathologies in a mouse model of Alzheimer’s disease

Lamotrigine(LTG)is a widely used drug for the treatment of epilepsy.Emerging clinical evidence suggests that LTG may improve cognitive function in patients with Alzheimer’s disease.However,the underlying molecular mechanisms remain unclear.In this study,amyloid precursor protein/presenilin 1(APP/PS1)double transgenic mice were used as a model of Alzheimer’s disease.Five-month-old APP/PS1 mice were intragastrically administered 30 mg/kg LTG or vehicle once per day for 3 successive months.The cognitive functions of animals were assessed using Morris water maze.Hyperphosphorylated tau and markers of synapse and glial cells were detected by western blot assay.The cell damage in the brain was investigated using hematoxylin and eosin staining.The levels of amyloid-βand the concentrations of interleukin-1β,interleukin-6 and tumor necrosis factor-αin the brain were measured using enzyme-linked immunosorbent assay.Differentially expressed genes in the brain after LTG treatment were analyzed by high-throughput RNA sequencing and real-time polymerase chain reaction.We found that LTG substantially improved spatial cognitive deficits of APP/PS1 mice;alleviated damage to synapses and nerve cells in the brain;and reduced amyloid-βlevels,tau protein hyperphosphorylation,and inflammatory responses.High-throughput RNA sequencing revealed that the beneficial effects of LTG on Alzheimer’s disease-related neuropathologies may have been mediated by the regulation of Ptgds,Cd74,Map3k1,Fosb,and Spp1 expression in the brain.These findings revealed potential molecular mechanisms by which LTG treatment improved Alzheimer’s disease.Furthermore,these data indicate that LTG may be a promising therapeutic drug for Alzheimer’s disease.

Long-term exercise training inhibits inflammation by suppressing hippocampal NLRP3 in APP/PS1 mice

Behavioral experiments have demonstrated that long-term physical exercise can be beneficial for learning and memory dysfunction caused by neuroinflammation in Alzheimer's disease(AD).However,the molecular mechanism remains poorly understood due to a lack of sufficient pertinent biochemical evidence.We investigated the potential effect of long-term physical exercise on cognition and hippocampal gene and protein expression changes in a transgenic AD mouse model.Following twenty weeks of treadmill exercise,transgenic AD mice showed improvement in cognitive functions and downregulation of Nod-like receptor protein 3(NLRP3)(p<0.01),interleukin-1beta(IL-1β)(p<0.05),and amyloid-β1-42(Aβ1-42)(p<0.05)expression levels.In addition,we observed significant reductions of microglial activation and hippocampal neuronal damage in the exercised AD mice(p<0.01),which might be a result of the downregulation of NLRP3-mediated signaling and neuroinflammatory responses.As neuronal damage due to inflammation might be a likely cause of AD-associated cognitive dysfunction.Our results suggested that the anti-inflammatory effects of exercise training involved downregulating the expression of key inflammatory factors and might play an important role in protecting hippocampal neurons against damage during the course of AD.

Effect of Human Umbilical Cord Mesenchymal Stem Cells on GRP78/ATF4 Pathway in Alzheimer s Disease Model Mice

[Objectives]To study the effect of human umbilical cord mesenchymal stem cells(hUC-MSCs)on GRP78/ATF4 pathway in APP/PS1 mice.[Methods]Twelve 6-month-old female APP/PS1 mice were randomly divided into model group(MOD,n=6)and human umbilical cord mesenchymal stem cell treatment group(MSC,n=6);six 6-month-old C57BL/6N mice were used as control group(CON,n=6).The mice in each group were treated with the fourth generation of human umbilical cord mesenchymal stem cells through tail vein.Four weeks later,the mice in each group were killed.The expression of GFP78 and ATF4 in the cortex of mice in each group was detected by Western blotting and real-time fluorescence quantitative PCR.[Results]The results of immunoblotting and real-time fluorescence quantitative PCR showed that the expression of GRP78 in MOD group was lower than that in CON group and the expression of ATF4 increased.The expression of GRP78 protein in MSC group was higher than that in MOD group,but the expression of ATF4 protein was lower.The results of real-time fluorescence quantitative PCR showed that the mRNA level of GRP78 decreased and the mRNA level of ATF4 increased in MOD group compared with CON group.The mRNA level of GRP78 in MSC group was higher than that in MOD group,while the mRNA level of ATF4 in MSC group was lower than that in MOD group.[Conclusions]Human umbilical cord mesenchymal stem cells can regulate the expression of GRP78/ATF4 pathway in APP/PSI mice,which may be related to the stress level of endoplasmic reticulum in the brain of APP/PS1 mice mediated by human umbilical cord mesenchymal stem cells.

Enhanced autophagic clearance of amyloid-βvia histone deacetylase 6-mediated V-ATPase assembly and lysosomal acidification protects against Alzheimer's disease in vitro and in vivo

Recent studies have suggested that abnormal acidification of lysosomes induces autophagic accumulation of amyloid-βin neurons,which is a key step in senile plaque formation.Therefore,resto ring normal lysosomal function and rebalancing lysosomal acidification in neurons in the brain may be a new treatment strategy for Alzheimer's disease.Microtubule acetylation/deacetylation plays a central role in lysosomal acidification.Here,we show that inhibiting the classic microtubule deacetylase histone deacetylase 6 with an histone deacetylase 6 shRNA or thehistone deacetylase 6 inhibitor valproic acid promoted lysosomal reacidification by modulating V-ATPase assembly in Alzheimer's disease.Fu rthermore,we found that treatment with valproic acid markedly enhanced autophagy.promoted clearance of amyloid-βaggregates,and ameliorated cognitive deficits in a mouse model of Alzheimer's disease.Our findings demonstrate a previously unknown neuroprotective mechanism in Alzheimer's disease,in which histone deacetylase 6 inhibition by valproic acid increases V-ATPase assembly and lysosomal acidification.