Alzheimer's Disease Model Group Research Articles

Semaglutide promotes the transition of microglia from M1 to M2 type to reduce brain inflammation in APP/PS1/tau mice.

A growing number of studies show that the diabetes drug Semaglutide is neuroprotective in Alzheimer's disease (AD) animal models, but its mode of action is not fully understood. In order to explore the mechanism of Semaglutide, 7-month-old APP/PS1/tau transgenic (3xTg) mice and wild-type (WT) mice were randomly divided into four groups: control group (WT + PBS), AD model group (3xTg + PBS), Semaglutide control group (WT + Semaglutide) and Semaglutide treatment group (3xTg + Semaglutide). Semaglutide (25 nmol/kg) or PBS was administered intraperitoneally once every two days for 30 days, followed by behavioral and molecular experiments. The results show that Semaglutide can improve working memory and spatial reference memory of 3xTg-AD mice, promote the release of anti-inflammatory factors and inhibit the production of pro-inflammatory factors in the cortex and hippocampus, and reduce Aβ deposition in the hippocampal CA1 region of 3xTg mice. Semaglutide can inhibit the apoptosis of BV2 cells induced by Aβ1-42 in a dose-dependent manner and promote the transformation of microglia from M1 to M2, thereby exerting anti-inflammatory and neuroprotective effects. Therefore, we speculate that Semaglutide shows an anti-inflammatory effect by promoting the transformation of microglia from M1 to M2 type in the brain of 3xTg mice, and thus exerts a neuroprotective effect.

Copper Overload Promotes β-amyloid Induced NLRP3/Caspase-1/GSDMD-Mediated Pyroptosis in Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by cognitive decline and abnormal protein accumulation. Copper imbalance and pyroptosis play significant roles in the pathogenesis of AD. Recent studies have suggested that dysregulated copper homeostasis contributed to β-amyloid accumulation, which may activate the NOD-like receptor protein 3 (NLRP3)-related pyroptosis pathway, promoting neuronal damages and AD progression. Therefore, the present study aims to investigates whether copper facilitates AD through exacerbating β-amyloid (Aβ) induced activation of NLRP3/Caspase-1/Gasdermin D (GSDMD)-mediated neuronal cell pyroptosis. Mouse hippocampal HT-22 cells were cultured with Aβ1-42 oligomer for 24 h as AD Model group. CuCl2 treatment was administered to the AD cell model, and cell survivability levels were detected by Cell Counting Kit-8 (CCK-8), TdT-mediated dUTP nick end labeling (TUNEL), and other relevant kits. Mitochondrial function was evaluated using Mitochondrial membrane potential dye JC-1 and transmission electron microscopy (TEM). After intervention with the NLRP3 inhibitor MCC950, activation of the NLRP3/Caspase-1/GSDMD pathway by copper ions (Cu2+) was confirmed via Western Blot. Thioredoxin T (ThT) fluorescence assay was performed to observe the aggregation effect of Aβ induced by Cu2+ overload. CuCl2 treatment of the AD cell model resulted in up-regulation of the levels of Lactate Dehydrogenase (LDH), Interleukin-1β (IL-1β), and IL-18 expression, which indicated activation of pyroptosis. We observed a significant decrease in mitochondrial membrane potential, mitochondrial swelling, and loss of mitochondrial cristae by fluorescence microscopy and TEM. ThT fluorescence imaging showed that Cu2+ promoted Aβ aggregation and up-regulated NLRP3, apoptosis-associated speck-like protein containing a CARD (ACS), Caspase-1, Cleaved Caspase-1, GSDMD, and Gasdermin D N-terminal (GSDMD-NT). The NLRP3 inhibitor MCC950 partially reversed Cu2+-mediated pyroptosis in HT-22 cells. Exposure to copper ions disrupt mitochondrial copper homeostasis, promotes Aβ aggregation, and activates NLRP3 inflammasomes, further promoting the Aβ aggregation activated pyroptosis in AD cell models.

Yigong San improves cognitive decline in a rat model of Alzheimer's disease by regulating intestinal microorganisms

To investigate the effect of Yigong San (YGS) on learning and memory abilities of rats with lipopolysaccharide (LPS)‑induced cognitive decline and explore its possible mechanism in light of intestinal microbiota. Forty SD rats were randomly divided into control group, model group, donepezil (1.3 mg/kg) group, and high-dose (5.25 g/kg) and low-dose (2.63 g/kg) YGS treatment groups. After 24 days of treatment with the corresponding drugs or water by gavage, the rats in the latter 4 groups received an intraperitoneal injection of LPS (0.5 mg/kg) to establish models of Alzheimer's disease (AD). Water maze test and HE staining were used to evaluate the changes in learning and memory abilities and pathomorphology of the hippocampus. The changes in gut microbial species of the rats were analyzed with 16S rRNA sequencing, and the levels of IL-6, TNF-α, and IL-1β in the brain tissue and serum were detected using ELISA. Compared with the AD model group, the YGS-treated rats showed significantly shortened escape latency on day 5 after modeling, reduced neuronal degeneration and necrosis in the hippocampus, lowered pathological score of cell damage, and decreased levels IL-6, TNF-α and IL-1β in the brain tissue and serum. The YGS-treated rats showed also obvious reduction of Alpha diversity indicators (ACE and Chao1) of intestinal microbiota with significantly increased abundance of Prevotellaceae species at the family level and decreased abundance of Desulfovibrionaceae, which were involved in such metabolic signaling pathways as cell community prokaryotes, membrane transport, and energy metabolism. YGS improves learning and memory abilities and hippocampal pathomorphology in AD rat models possibly by regulating the abundance of intestinal microbial species such as Prevotellaceae to affect the metabolic pathways for signal transduction, cofactors, and vitamin metabolism.

Jiaotaiwan improves brain glucose metabolism in a mouse model of Alzheimer's disease by activating the PI3K/AKT signaling pathway

To investigate the effect of Jiaotaiwan on brain insulin-PI3K/AKT pathway in a mouse model of Alzheimer's disease (AD). Fifty 3-month-old male APP/PS1 double transgenic mice were randomized into AD model group, low-, medium- and high-dose Jiaotaiwan treatment groups, and donepezil treatment group. Cognitive functions of the mice were assessed using water maze and open field tests, and neuronal pathologies were observed with HE staining and Nissl staining; immunohistochemistry was used to detect amyloid Aβ deposition in the brain. Fasting serum insulin levels of the mice were measured, and the expressions of Aβ42, insulin-PI3K/AKT pathway components and downstream glucose transporters in the brain tissue were detected with RT-qPCR and Western blotting. The AD mouse models exhibited obvious impairment of learning and memory abilities, significantly reduced hippocampal neurons, and obvious Aβ amyloid plaques in the brain tissue with increased Aβ42 protein expression (P < 0.05) and insulin resistance index, decreased hippocampal PI3K expressions, lowered expressions of AKT and InR, reduced expressions of GLUT1, GLUT3, and GLUT4, and increased expression of GSK3β in both the hippocampus and cortex. Treatment with Jiaotaiwan and donepezil both effectively improved memory ability of the mouse models, increased the number of hippocampal neurons, reduced Aβ amyloid plaques and increased the expressions of PI3K, AKT, InR, GLUT1, GLUT3 and GLUT4 in the hippocampus and cortex. Jiaotaiwan improves learning and memory abilities of APP/PS1 double transgenic mice and delay the development of AD by activating the PI3K/AKT pathway and regulating the expression levels of its downstream GLUTs in the brain.

An interventional study of baicalin on neuronal pentraxin-1, neuronal pentraxin-2, and C-reactive protein in Alzheimer's disease rat model.

Baicalin has been shown to promote spatial learning and neural regeneration, which might increase the differentiation of neural stem cells in Alzheimer's disease (AD) rat models. We aimed to study the role of baicalin on neuronal pentraxin-1 (NPTX-1), neuronal pentraxin-2 (NPTX-2), and C-reactive protein (CRP) in AD model rats. The 30 male Sprague Dawley rats were divided into three groups: the control group, the AD model group, and the AD + baicalin group. Then, the Morris water maze was used to verify the effect of baicalin on the memory and spatial learning of rats. Immunohistochemistry and immunofluorescence were used to observe the expression of NPTX-1, NPTX-2, and CRP in brain tissue. Compared with the AD model group, the AD rats treated with baicalin spent significantly less time finding escape latencies (P = 0.008) and had longer cross-platform times in the target quadrant (P = 0.015). In addition, the AD + baicalin group had significantly higher numbers of hippocampal neurons compared with the AD model group (P < 0.05). Baicalin also obviously decreased the apoptosis of neurons. Moreover, compared with the AD model group, the NPTX-1 and CRP expression in the AD + baicalin group was significantly reduced (P = 0.000) while the expression of NPTX-2 in the brain tissue of AD rats was significantly increased (P = 0.000). Baicalin can play a therapeutic role by downregulating NPTX-1, upregulating NPTX-2, and downregulating CPR in AD model rats.

Integrated approach on UPLC-QTOF/MS based active plasma component and metabolomics analysis of Gan Mai Da Zao decoction on the treatment of Alzheimer's disease in rats plasma and urine

Alzheimer's disease is the most common form of dementia and affects human health. In this study, a classic prescription of Chinese Medicine Gan-Mai-Da-Zao decoction was used for treating Alzheimer's disease for the first time. Hence, firstly components of Gan-Mai-Da-Zao decoction in plasma were screened using UPLC-QTOF/MS. Then the MWM, HE and Metabolomics methods were used to examine the effect of Gan-Mai-Da-Zao decoction on Alzheimer's disease rats. The results showed 9 active components in ESI+ and 3 active components in ESI− of Gan-Mai-Da-Zao decoction in blood were identified, and Gan-Mai-Da-Zao decoction improved the learning and memory ability and pathological damage in Alzheimer's disease rats. 57 plasma metabolites and 21 urine metabolites were returned to normal in Alzheimer's disease model group after Gan-Mai-Da-Zao decoction treatment. 2-hydroxyestradiol, biotin, 4,6-dihydroxyquinoline, morphine-6-glucuronide, riboflavin can clearly distinguish between Gan-Mai-Da-Zao decoction-treated group and Alzheimer's disease model group involving steroid hormone biosynthesis, biotin metabolism, tryptophan metabolism, drug metabolism - cytochrome P450, and riboflavin metabolism pathway, which were the main pathways of Gan-Mai-Da-Zao decoction treatment on Alzheimer's disease. This study may bring a deeper understanding of the Alzheimer's disease-associated metabolic profile and the therapeutic mechanism of Gan-Mai-Da-Zao decoction on Alzheimer's disease.

A UPLC-Q-TOF/MS-Based Metabolomics Study on the Effect of Corallodiscus flabellatus (Craib) B. L. Burtt Extract on Alzheimer's Disease.

A UPLC-Q-TOF/MS-based metabolomics study was carried out to explore the intervening mechanism of Corallodiscus flabellatus (Craib) B. L. Burtt (CF) extract on Alzheimer's disease (AD). The AD model group consisted of senescence-accelerated mouse prone 8 (SAMP8) mice, and the control group consisted of senescence-accelerated mouse resistant 1 (SAMR1) mice. UPLC-Q-TOF/MS detection, multivariate statistical analysis, and pathway enrichment were jointly performed to research the change in metabolite profiling in the urine of AD mice. The result suggested that the metabolite profiling of SAMP8 mice significantly changed at the sixth month compared with SAMR1 mice of the same age, and the principal component analysis (PCA) score scatter plots of the CF group closely resembled those of the control and positive drug (huperzine A, HA) group. A total of 28 metabolites were considered potential biomarkers associated with the metabolism of beta-alanine, glycine, serine, threonine, cysteine, methionine, arginine, proline, and purines in AD mice. Furthermore, the CF group was clustered with the control and positive group and was clearly separated from the model group in the heat map. In conclusion, significant anti-AD effects were firstly observed in mice after treatment with the CF extract, and the urinary metabolomics approach assisted with dissecting the underlying mechanism.

Melatonin Improves Short-Term Spatial Memory in a Mouse Model of Alzheimer's Disease.

IntroductionAlzheimer’s disease (AD) is a neurodegenerative disease that has become a leading cause of death in recent years. Impairments in spatial learning and memory are an important clinical feature of AD. Melatonin (MLT), the main product secreted by the pineal gland, showed multiple antioxidant, anti-inflammatory, and neuroprotective properties.PurposeThe present study aimed to explore the possible prophylactic effects of MLT against spatial memory deficits in a sporadic mouse model of AD induced by D-galactose and aluminium chloride (AlCl3).MethodsFour groups of mice (n = 10 per group) were prepared: control, AD (the D-galactose and AlCl3 AD model group), AD+MLT (AD mice treated with 80 mg/kg MLT), and AD+DON (AD mice treated with 3 mg/kg donepezil). We then used the object location and Y-maze tests to assess spatial memory in the four groups. Gene expression levels of brain-derived neurotrophic factor (Bdnf) and cAMP-responsive element-binding protein (Creb1) were measured using real-time polymerase chain reaction.ResultsWe found that MLT improved spatial memory in the sporadic AD mice. MLT ameliorated Creb1 gene expression and significantly increased Bdnf gene expression in the hippocampus of AD model mice compared with the AD group.ConclusionMLT could have a substantial potential to alleviate memory impairment in sporadic AD if introduced at early stages.

A study on inhibition of the Aβ1-42-induced inflammatory response by the Huatuo Zaizao pill through the NF-κB signaling pathway.

The pathology of Alzheimer's disease (AD) includes β-amyloid (Aβ) (plaques) and neurofibrillary tangles (NFTs). This study aimed to explore the efficacy of Huatuo Zaizao pill (HTZP) in an AD mouse model induced by injecting Aβ1-42, and the neuroprotective mechanism of HTZP in AD. C57BL/6 (B6) mice were randomly divided into 4 groups (n = 10, per group): control group, AD model group, and 2 different doses of HTZP treated groups. The Morris water maze test was carried out on AD mice to assess the learning ability after treatment with HTZP for 15 day. The levels of inflammatory factors and the nuclear factor-κB (NF-κB) pathway were examined by western blot and real-time polymerase chain reaction (PCR). The content of microglia was investigated by immunofluorescence. This study revealed that a cognitive disorder could be mitigated when the AD mice were treated with HTZP, which might be associated with the decreased level of pro-inflammatory factors, and the inhibitory activities of microglia. Additionally, phosphorylation of IκB and NF-κB p65 could be reduced by prohibiting the neuroinflammation of NF-κB activation in the hippocampus of AD mice. These results showed that HTZP could mitigate a cognitive disorder, diminish the activation of microglia, and inhibit the content of inflammatory factors through the NF-κB pathway in Aβ1-42-induced AD mice. HTZP may be an appropriate agent for AD treatment in the future.

Crocin attenuates the granular cells damages on the dentate gyrus and pyramidal neurons in the CA3 regions of the hippocampus and frontal cortex in the rat model of Alzheimer's disease

Amyloid β-peptides (Aβ) are considered as a major hallmark of Alzheimer's disease (AD) that can induce synaptic loss and apoptosis in brain regions, particularly in the cortex and the hippocampus. Evidence suggests that crocin, as the major component of saffron, can exhibit neuromodulatory effects in AD. However, specific data related to their efficacy to attenuate the synaptic loss and neuronal death in animal models of AD are limited. Hence, we investigated the efficacy of crocin in the CA3 and dentate gyrus (DG) regions of the hippocampus and also in frontal cortex neurons employing a rat model of AD. Male Wistar rats were randomly divided into control, sham, AD model, crocin, and AD model + crocin groups, with 8 rats per group. AD model was established by injecting Aβ1–42 into the frontal cortex rats, and thereafter the rats were administrated by crocin (30 mg/kg) for a duration of 12-day. The number of live cells, neuronal arborization and apoptosis were measured using a Cresyl violet, Golgi-Cox and TUNEL staining, respectively. Results showed that, the number of live cells in the hippocampus pyramidal neurons in the CA3 and granular cells in the DG regions of the AD rats significantly decreased, which was significantly rescued by crocin. Compared with the control group, the axonal, spine and dendrites arborization in the frontal cortex and CA3 region of the AD model group significantly decreased. The crocin could significantly reverse this arborization loss in the AD rats (P < 0.05). The apoptotic cell number in the CA3 and DG regions in the AD model group was significantly higher than that of the control group (P < 0.05), while crocin significantly decreased the apoptotic cell number in the AD group (P < 0.05). Conclusion. Crocin can improve the synaptic loss and neuronal death of the AD rats possibly by reducing the neuronal apoptosis.

Corydalis edulis total alkaloids (CETA) ameliorates cognitive dysfunction in rat model of Alzheimer disease through regulation of the antioxidant stress and MAP2/NF-κB

BackgroundIn recent years, the morbidity of Alzheimer's disease in the world has become more and more serious. Therefore, it is an important means to find new drugs for treating AD from traditional medicines. It was found that Corydalis edulis Maxim. has a significant effect in the treatment of Alzheimer's disease (AD) in traditional application. In this work, we evaluated the efficacy of Corydalis edulis Maxim. total alkaloids (CETA) in AD model rats. MethodsIn this work, CETA was prepared by alkali extraction and acid precipitation, 11 alkaloids were identified by UPLC-MS/MS from CETA. AD model rats induced with D-galactose (D-gal) for 7 weeks. In modeling, the different doses of CETA (5, 20 mg/kg/Day) were continuously administered. Firstly, the change of the cognitive function, behavior, brain tissue pathology, and the activity of ROS, MDA, SOD, IL-1β, TNF-α and CAT in rat hippocampal homogenate was measurement. Finally, the protein expression of Aβ, microtubule-associated protein 2 (MAP2) and nuclear factor (κBp65) in rat brain was measurement. ResultCETA was found to have the activity in regulating AD. Compared with the normal control group, the levels of SOD and CAT in the hippocampus of the AD model group were decreased, and the level of ROS, MDA, IL-1β and TNF-α was increased. The protein expression of Aβ, and NF-κB were increased, and MAP2 were decreased. After treatment by CETA, the levels of SOD and CAT in hippocampus of AD model rats was significantly increased, ROS, MDA, IL-1β and TNF-α were significantly decreased. The protein expression of Aβ, and NF-κB were decreased, and MAP2 were increased. ConclusionCETA can improve the learning and memory ability in AD model. The mechanism may be achieved by regulating the oxidative stress and inflammatory of AD rats, inhibiting the protein expression levels of Aβ, and NF-κB, and promote the protein expression the levels of MAP2. Among them, 5 mg/kg is more effective than 20 mg/kg of CETA. Therefore, the therapeutic potential of CETA has been confirmed by our research, which may be a valuable drug for the treatment of AD.

High-throughput lipidomics analysis to discover lipid biomarkers and profiles as potential targets for evaluating efficacy of Kai-Xin-San against APP/PS1 transgenic mice based on UPLC-Q/TOF-MS.

Lipid metabolism has a significant function in the central nervous system and Alzheimer's disease (AD) is an age-related senile disease characterized by central nerve degeneration. The pathological development of AD is closely related to lipid metabolism disorders. To reveal the influence of Kai-Xin-San (KXS) on lipid metabolism in APP/PSI transgenic mice and potential therapeutic targets for treating AD, brain tissue samples were collected and analyzed by high-throughput lipidomics based on UPLC-Q/TOF-MS. The collected raw data were processed by multivariate data analysis to discover the potential biomarkers and lipid metabolic profiles. Compared with the control wild-type mouse group, nine potential lipid biomarkers were found in the AD model group, of which seven were up-regulated and two were down-regulated. Orally administrated KXS can reverse the changes in these potential biomarkers. Compared with the model group, a total of six differential metabolites showed a recovery trend and may be potential targets for KXS to treat AD. This study showed that high-throughput lipidomics can be used to discover the perturbed pathways and lipid biomarkers as potential targets to reveal the therapeutic effects of KXS.

Protective effect of ISO‑1 against advanced glycation end product aggravation of PC12 cell injury induced by Aβ1‑40.

Advanced glycation end products (AGEs) are important pathogenic substances involved in diabetes mellitus (DM) and its complications. AGEs also serve important roles in promoting the development of Alzheimer's disease (AD). Macrophage migration inhibitory factor (MIF), an inflammatory stimulant and a pathogenic factor involved in DM, was previously reported to be present at increased levels in the cerebrospinal fluid of patients with AD and mild cognitive impairment compared with age-matched healthy controls. By investigating the association between AGEs and MIF, and the effects of neuroinflammation on AD, the present study aimed to increase understanding of the specific molecular mechanisms involved in the pathogenesis of DM and AD, and the connection between these diseases. PC12 cells were cultured in vitro; the levels of MIF mRNA and protein were determined using reverse transcription-quantitative (RT-q)PCR and western blot analyses. The optimal concentrations of AGEs and amyloid β 1–40 (Aβ1–40) were also determined in the cell model of AD using Cell Counting Kit-8 and MTT assays. Cell numbers and morphological changes were observed following the treatment of Aβ1–40-stimulated PC12 cells with AGEs and the MIF inhibitor (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1). The mRNA expression levels of interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α) and MIF were determined via RT-qPCR analysis. The results showed that the levels of MIF mRNA and protein were significantly increased in cells treated with AGEs compared with the control group. In the AD model group, the inhibition of PC12 cell growth was significantly increased, and the mRNA expression levels of IL-1β, IL-6, TNF-α and MIF were also increased. Compared with treatment with AGEs alone, the combination of AGEs treatment with ISO-1 significantly improved the survival rate and resulted in the reduced expression of inflammatory mediators in the AD cell model. Thus, ISO-1 reduced AGEs-mediated damage in the AD cell model. This may be a consequence of AGEs-mediated MIF expression promoting neuritis in the AD cell model, whereas ISO-1 decreased the expression of neuroinflammatory mediators.

Protective effects of Cerebralcare Granule® against the learning and memory impairment in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is an age‐related neurodegenerative disorder characterized by the impairment of cognition, memory, language and behavioral function. So far, there are no efficacious drugs approved for the treatment of AD. Cerebralcare Granule (CG) is a compound Chinese medicine used for treatment of headache and dizziness associated with cerebrovascular diseases. Increasing evidence indicates that CG can improve the cerebral microcirculatory disturbance and has a protective effect on the neural damage, which suggests CG may be a promising medicine for AD.Herein, this study investigated the potential effect of CG on AD in the Senescence Accelerated Prone Mouse 8 (SAMP8) mouse. Male 7‐month‐old SAMP8 mice were randomly divided into five groups: AD model group, CG treatment groups (935, 1870 and 3740 mg/kg), and donepezil treatment group (1.3 mg/kg). After intragastric administration with CG for two months, behavioral tests were conducted to evaluate the neuroprotective effects of CG. Ultrastructural changes of neurons and synapses in the hippocampus of the mice were observed. The expressional levels of BDNF, NGF, and TrkA were analyzed through immunohistochemistry. Western blotting was used to analyze the expressional levels of GAP‐43, SYP, and PSD‐95. Biochemical analysis was performed to assess the activities of total antioxidant capacity (T‐AOC), SOD, and GSH‐Px, and the content of GSH and MDA.The findings showed that CG dose‐dependently attenuated the impairment of spontaneous alternation behavior and donepezil treatment had a significant effect in attenuating the impairment of spontaneous alternation behavior. The mice in the CG‐treatment groups (1870 and 3740 mg/kg) consistently took a less time to find the platform than the model group in the Morris water maze test. CG and donepezil treatment alleviated the synaptic ultrastructure damage in the hippocampal CA1 region of the SAMP8 mouse and normal synaptic morphology and structure was maintained. CG can increase the levels of activities of GSH (change ratio of 45.5%), T‐AOC (change ratio of 40.9%), SOD (change ratio of 171.9%) and GSH‐Px (change ratio of 117.4%), and decrease the content of MDA (change ratio of 60.7%). Compared with the model group, the group with 3740mg/kg CG showed a significantly increased expression of SYP and PSD‐95 in the hippocampus and cerebral cortex. The group treated with either 3740 mg/kg CG or with donepezil showed a significantly increased expression of BDNF(change ratio of 38.2%), NGF (change ratio of 41.9%) and the neurotrophic factor receptor TrkA (change ratio of 46.9%), compared with the model group.The above results suggest that CG can alleviate the learning and memory impairment of AD mice via inhibiting oxidative stress, increasing neurotrophic factors and mitigating synaptic damage.Support or Funding InformationSupported by Tianjin Science and Technology's Plan (16PTSYJC00270).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Electro-acupuncture therapy to improve spatial learning and memory in APPswe/PS1dE9 transgenic mice through the inhibition of the TLR4/MyD88 signaling pathway

Abstract Objective To determine whether electro-acupuncture (EA) therapy could improve the cognitive functions of amyloid precursor protein Swedish mutation (APPswe)/presenilin 1 deleted in exon 9 (PS1dE9) mice and examine whether EA treatment could attenuate neuroinflammation by targeting the toll-like receptor 4 (TLR4)/myeloid differentiation primary response factor 88 (MyD88) signaling pathway. Methods Twenty-seven double transgenic APPswe/PS1dE9 mice were randomly allocated into three groups: an Alzheimer's disease model group (AD group), a medication group (M group) and an EA treatment group (EA group). Each group contained nine mice, and nine wild-type mice were used in a normal group (N group). The animals in the M group were treated with oral administrations of 0.92 mg/kg donepezil hydrochloride for 15 days. For animals in the EA group, EA treatments were used on the Yintang (GV 29) and Baihui (GV 20) acupoints for 20 minutes, and the Shuigou (GV 26) acupoint was pricked without needle retention following EA treatments. Following treatments, the spatial learning and memory of the mice were measured using the Morris water maze test. The expression levels of TLR4, MyD88, nuclear factor kappa B (NF-κB) and inducible nitric oxide synthase (iNOS) were analyzed by immunohistochemical staining and western blot. Results The escape latencies of the M and EA groups were significantly lower than those of the AD group (vs M, P = .002; vs EA, P Conclusion EA treatment enhanced the memory and learning abilities of APPswe/PS1dE9 mice by regulating the TLR4/MyD88 inflammatory signaling pathway.

Dulaglutide ameliorates STZ induced AD-like impairment of learning and memory ability by modulating hyperphosphorylation of tau and NFs through GSK3β

Dulaglutide, a novel long-acting glucagon-like peptide 1 (GLP-1) receptor agonist, is an incretin mimetic approved for type 2 diabetes mellitus (T2DM) treatment. Alzheimer's disease (AD) is called type 3 diabetes. The aim of this study is to explore the effects of dulaglutide on the learning and memory impairment in AD mice induced by injection of streptozocin (STZ) via intracerebroventricularly (i.c.v.). 32 male C57/BL6 mice were randomly divided into four groups: control group (CON); AD model group (STZ); dulaglutide treated (Dul); dulaglutide and exendin(9–39) (Ex). Western blotting was used to detect the levels of phosphorylated tau, neurofilament (NFs) proteins and phosphorylated PI3K/AKT/GSK3β signaling pathway. Morris water maze (MWM) test was used to assess the spatial learning and memory ability. The results displayed that the hyperphosphorylation of tau and NFs were increased in the STZ and Ex groups compared to the control and Dul groups. Dulaglutide also significantly shortened the escape latency and increased the number of hidden platform crossings in MWM test. The effects of dulaglutide on decreasing the hyperphosphorylation of tau and NFs proteins through improving the PI3K/AKT/GSK3β signaling pathway may be related to its protective effects on impairment of AD-like learning and memory.

Epigenetic mechanisms underlying the effects of triptolide and tripchlorolide on the expression of neuroligin-1 in the hippocampus of APP/PS1 transgenic mice

Context: Neuroligin-1 (NLGN1) is a cell adhesion protein located on the excitatory postsynaptic membrane. β-Amyloid (Aβ)-induced neuroinflammation decreases NLGN1 expression through epigenetic mechanisms. Triptolide (T10) and tripchlorolide (T4) exert protective effects on synapses in Alzheimer's disease (AD) mice, but the mechanisms remain unclear.Objective: The effects of T10 and T4 on hippocampal NLGN1 expression in AD mice and the epigenetic mechanisms were assessed using chromatin immunoprecipitation and methylated DNA immunoprecipitation.Materials and methods: Sixty APP/PS1 transgenic mice were randomly divided into an AD model group, a T10-treated group and a T4-treated group (n = 20); 20 wild-type littermates served as the control group. APP/PS1 transgenic mice were intraperitoneally injected with T10 (0.1 mg/kg) and T4 (25 μg/kg) once per day for 60 days. NLGN1 expression was examined using western blotting and quantitative PCR.Results: T10 and T4 increased the levels of the NLGN1 protein and mRNA in hippocampus of AD mice. T10 and T4 inhibited the binding of HDAC2 (p< 0.01) and MeCP2 (p< 0.01 and p< 0.05, respectively) to the NLGN1 promoter, and cytosine methylation (1.2305 ± 0.1482/1.2554 ± 0.3570 vs. 1.6578 ± 0.1818, p< 0.01) at the NLGN1 promoter in the hippocampus of AD mice. T10 and T4 increased the level of acetylated histone H3 (0.7733 ± 0.1611/0.8241 ± 0.0964 vs. 0.5587 ± 0.0925, p< 0.01) at the NLGN1 promoter in the hippocampus of AD mice.Conclusions: T10 and T4 may increase hippocampal NLGN1 expression in AD mice through epigenetic mechanisms, providing a new explanation for the mechanism underlying the protective effects of T10 and T4 on synapses.

Possible mechanism of Vitis vinifera L. flavones on neurotransmitters, synaptic transmission and related learning and memory in Alzheimer model rats

BackgroundThis study explored the possible mechanism of flavones from Vitis vinifera L. (VTF) on neurotransmitters, synaptic transmission and related learning and memory in rats with Alzheimer disease (AD).MethodsThe researchers injected amyloid-β(25–35) into the hippocampus to establish AD model rats. The Sprague-Dawley (SD) rats were divided into a control group, a donepezil group, an AD model group, a VTF low-dose group, a VTF medium-dose group and a VTF high-dose group. The researchers detected the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) according to kit instructions. The protein expression of brain-derived neurotrophic factor (BDNF), synaptotagmin-1 (SYT1) and cyclic adenosine monophosphate response element binding protein (CREB) in the rats’ hippocampi was detected by immunohistochemistry and Western blot, and the gene expression of cAMP-regulated enhancer (CRE) was detected by real-time quantitative polymerase chain reaction (PCR).ResultsVTF may enhance the protein expression of p-CREB, BDNF and SYT1 in rat hippocampi, depending on dose. The messenger RNA (mRNA) level of CREB was significantly higher in the VTF high-dose group than in the model group, which was consistent with the results of Western blotting. VTF may reduce the activity of AChE and increase that of ChAT in rat hippocampi. Finally, VTF effectively improved the learning and memory abilities of AD rats.ConclusionsVTF can promote synaptic plasticity and indirectly affect the expression of cholinergic neurotransmitters, which may be one mechanism of VTF protection in AD rats.

Reproduction,genotype identification and evaluation of APP/PS1 transgenic mice

To identify the genotype of (APP/PS1) transgenic mice and evaluate the changing of cognitive and behavioral fu nctions, provide an effective animal model for the Alzheimer's disease (AD) research. Male APP/PS1 transgenic mice mated with female APP/PS1 transgenic mice, and the genotype of their filial mice was identified by PCR. The APP +/PS1 + mice were assigned into AD model group (AD group, n=8), and the APP/PS1 mice were assigned into control group (CT group, n=8). The Morris water maze test was carried out to detect the capacity of learning and memory of mice. After that, the mice were sacrificed and the brain tissues were sampled and stained by HE and congo red for the pathological examination. ①A APP/PS1 genome DNA about 360 bp size was detected. The methods of feeding and breeding were successful to attain APP/PS1 transgenic mice.②Statistical significance was found in the differences of the capacity of learning and memory between 7-month-old APP/PS1 positive mice and negative mice (P<0.05).③The results of HE stain showed that the structure and cellular morphology of hippocampus of AD mice were obviously abnormal. The results of congo red stain showed that positive amyloid plaque was observed in brains of AD mice. APP/PS1 transgenic mice present typical symptoms and behaviors of Alzheimer's disease. The transgenic mouse is an effective tool for the research and prevention of AD.

Regulatory mechanism of microRNA-377 on CDH13 expression in the cell model of Alzheimer's disease.

To explore whether microRNA-377 could participate in the development of Alzheimer's disease (AD) by regulating CDH13. In this research, AD model was constructed by the SH-SY5Y cells. The expression levels of microRNA-377 and CDH13 in the AD model were detected by quantitative Real-time polymerase chain reaction (qRT-PCR). The cell viability and apoptosis after knockdown of microRNA-377 and CDH13 were measured by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. The regulatory mechanism of microRNA-377 on CDH13 was confirmed by dual-luciferase reporter gene assay, qRT-PCR and Western blot. Downregulated microRNA-377 and upregulated CDH13 were observed after successful construction of the AD model. Cell viability in the AD model group was significantly reduced compared with that of the control group. Moreover, downregulated microRNA-377 could further inhibit the cell viability, which was reversed by CDH13 knockdown. Cell apoptosis in the AD model group was enhanced after microRNA-377 knockdown, which was rescued by decreasing the expression level of CDH13. MicroRNA-377 was confirmed to regulate the expression level of CDH13 by dual-luciferase reporter gene assay, qRT-PCR and Western blot. MicroRNA-377 could regulate the expression level of CDH13 by promoting cell proliferation and inhibiting cell apoptosis, thus participating in the occurrence of the Alzheimer's disease.