Alzheimer's Disease Cell Model Research Articles

Identification of miRNA-mRNA Pairs in the Alzheimer's Disease Expression Profile and Explore the Effect of miR-26a-5p/PTGS2 on Amyloid-β Induced Neurotoxicity in Alzheimer's Disease Cell Model.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease and the most common type of dementia. MicroRNAs (miRNAs) have been extensively studied in many diseases, including AD. To identify the AD-specific differentially expressed miRNAs and mRNAs, we used bioinformatics analysis to study candidate miRNA–mRNA pairs involved in the pathogenesis of AD. These miRNA–mRNAs may serve as promising biomarkers for early diagnosis or targeted therapy of AD patients. In this study, based on the AD mRNA and miRNA expression profile data in Gene Expression Omnibus (GEO), through differential expression analysis, functional annotation and enrichment analysis, weighted gene co-expression network analysis, miRNA–mRNA regulatory network, protein–protein interaction network, receiver operator characteristic and Least absolute shrinkage and selection operator (LASSO) regression and other analysis, we screened the key miRNA–mRNA in the progress of AD: miR-26a-5p/PTGS2. Dual-luciferase and qPCR experiments confirmed that PTGS2 is a direct target gene of miR-26a-5p. The expression of miR-26a-5p in the peripheral blood of AD patients and AD model cells (SH-SY5Y cells treated with Aβ25–35) was up-regulated, and the expression of PTGS2 was down-regulated. Functional gain -loss experiments confirmed that PTGS2 protects AD model cells from damage by inhibiting proliferation and migration. However, the expression of miR-26a-5p promotes the proliferation of AD model cells. It is further found that PTGS2 is involved in the regulation of miR-26a-5p and can reverse the effect of miR-26a-5p on the proliferation of AD model cells. In addition, through network pharmacology, qPCR and CCK-8, we found that baicalein may affect the progression of AD by regulating the expression of PTGS2. Therefore, PTGS2 can be used as a target for AD research, and miR-26a-5p/PTGS2 can be used as an axis of action to study the pathogenesis of AD.

Cryptotanshinone Attenuates Amyloid-β42-induced Tau Phosphorylation by Regulating PI3K/Akt/GSK3β Pathway in HT22 Cells.

The pathological characteristics of Alzheimer's disease (AD) include formation of senile plaques resulting from amyloid-β (Aβ) deposition and neurofibrillary tangles caused by tau hyperphosphorylation. Reducing tau hyperphosphorylation is crucial for treatment of AD. Network pharmacology analysis showed that CTS may reduce tau hyperphosphorylation by regulating the phosphatidylinositol 3 kinases/protein kinase B/ glycogen synthase kinase-3β (PI3K/Akt/GSK3β) pathway. We investigated the ability of cryptotanshinone (CTS) to reduce Aβ-induced tau hyperphosphorylation and characterized the underlying mechanisms. Amyloid-β42 oligomers (AβO) were used to establish an AD model in HT22 cells. The expression levels of tau and related proteins in PI3K/Akt/GSK3β pathway were measured using western blot and immunofluorescence staining. The above-mentioned proteins were then evaluated in an okadaic acid (OKA)-induced AD cell model to verify the results. Synapse-associated proteins including post-synaptic density protein-95 (PSD95) and synaptophysin were also evaluated. We found that CTS significantly reduced tau hyperphosphorylation at Ser202, Ser404, Thr181, and Thr231 in AβO- and OKA-induced cell models. Moreover, we also found that CTS reversed AβO-induced reductions in the levels of PSD95 and synaptophysin. We used LY294002 to block PI3K and the results showed that CTS exerted neuroprotective effects through regulation of the PI3K/Akt/GSK3β signaling pathway. In summary, we showed for the first time that CTS inhibited AD-related tau hyperphosphorylation and reduced the effects of AβO on the expression levels of PSD95 and synaptophysin via the PI3K/Akt/GSK3β pathway in HT22 cells.

Screening neuroprotective compounds in herpes-induced Alzheimer's disease cell and 3D tissue models

Alzheimer's Disease (AD) is a neurodegenerative disorder that can cause life-altering and debilitating cognitive decline. AD's etiology is poorly understood, and no disease-modifying therapeutics exist. Here, we describe the use of 2D and 3D tissue culture models of herpesvirus-induced AD, which recapitulate hallmark disease features of plaque formation, gliosis, neuroinflammation, and impaired neuronal signaling, to screen a panel of 21 medications, supplements, and nutraceuticals with purported neuroprotective benefits. This screen identified green tea catechins and resveratrol as having strong anti-plaque properties, functional neuroprotective benefits, and minimal neurotoxicity, providing support for their further investigation as AD preventives and therapies. Two other candidates, citicoline and metformin, reduced plaque formation and were minimally toxic, but did not protect against virus-induced impairments in neuronal signaling. This study establishes a simple platform for rapidly screening and characterizing AD compounds of interest in 2D and 3D human cortical tissue models representing physiologically relevant disease features.

Baicalin Attenuated Aβ 1-42-Induced Apoptosis in SH-SY5Y Cells by Inhibiting the Ras-ERK Signaling Pathway.

Alzheimer's disease (AD) is a serious neurodegenerative disease. It is widely believed that the accumulation of amyloid beta (Aβ) in neurons around neurofibrillary plaques is the main pathological characteristic of AD; however, the molecular mechanism underlying these pathological changes is not clear. Baicalin is a flavonoid extracted from the dry root of Scutellaria baicalensis Georgi. Studies have shown that baicalin exerts excellent anti-inflammatory and neuroprotective effects. In this study, an AD cell model was established by exposing SH-SY5Y cells to Aβ1-42 and treating them with baicalin. Cell survival, cell cycle progression, and apoptosis were measured by MTT, flow cytometry, and immunofluorescence assays, respectively. The expression levels of Ras, ERK/ERK phosphorylation (p-ERK), and cyclin D1 were measured by Western blotting. In addition, whether the MEK activator could reverse the regulatory effect of baicalin on Ras-ERK signaling was investigated using Western blotting. We found that baicalin improved the survival, promoted the proliferation, and inhibited the apoptosis of SH-SY5Y cells after Aβ1-42 treatment. Baicalin also ameliorated Aβ1-42-induced cell cycle arrest at the S phase and induced apoptosis. Furthermore, baicalin inhibited the levels of Ras, p-ERK, and cyclin D1 induced by Aβ, and this effect could be reversed by the MEK activator. Therefore, we suggest that baicalin may regulate neuronal cell cycle progression and apoptosis in Aβ1-42-treated SH-SY5Y cells by inhibiting the Ras-ERK signaling pathway. This study suggested that baicalin might be a useful therapeutic agent for senile dementia, especially AD.

MiR-212-3p attenuates neuroinflammation of rats with Alzheimer's disease via regulating the SP1/BACE1/NLRP3/Caspase-1 signaling pathway.

Alzheimer’s disease (AD) ranks as the leading cause of dementia. MicroRNA (miR)-212-3p has been identified to exert neuroprotective effects on brain disorders. The current study analyzed the protective role of miR-212-3p in AD rats through regulating the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3)/Caspase-1 signaling pathway. The AD rat model was established through injection of amyloid-β 1-42 (Aβ1-42), followed by the Morris water maze test. The morphology and functions of neurons were observed. Furthermore, miR-212-3p, NLRP3, cleaved Caspase-1, gasdermin D N-terminus, interleukin (IL)-1β, and IL-18 expressions were measured. H19-7 cells were treated with Aβ1-42 to establish the AD cell model, followed by an assessment of cell viability and pyroptosis. Downstream targets of miR-212-3p and specificity protein 1 (SP1), as well as beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), were predicted by databases and testified using dual-luciferase and chromatin immunoprecipitation assays. miR-212-3p was weakly expressed in AD rats. miR-212-3p overexpression was linked to improved learning and memory capacities of AD rats and reduced neuronal pyroptosis linked to neuroinflammation attenuation. In vitro, miR-212-3p improved viability and suppressed pyroptosis of neurons through inhibiting NLRP3/Caspase-1. Overall, miR-212-3p inhibited SP1 expression to block BACE1-induced activation of NLRP3/Caspase-1, thereby attenuating neuroinflammation of AD rats.

Passion fruit seed extract protects beta-amyloid-induced neuronal cell death in a differentiated human neuroblastoma SH-SY5Y cell model.

Alzheimer's disease (AD) is a progressive neurodegenerative disease with accompanying perceptive disorder. We previously reported that decreasing levels of brain‐derived neurotrophic factor (BDNF) promoted beta‐amyloid (Aβ)‐induced neuronal cell death in neuron‐like differentiated SH‐SY5Y (ndSH‐SY5Y) human neuroblastoma cells in an AD mimic cell model. We investigated the neuroprotective effects of passion fruit seed extract (PFSE) and one of the main stilbene compounds, piceatannol, in an AD cell model using ndSH‐SY5Y cells. Both PFSE and piceatannol were found to protect Aβ‐induced neurite fragmentation in the cell model (protection efficacy; 34% in PFSE and 36% in piceatannol). In addition, both PFSE and piceatannol suppress Aβ‐induced neuronal cell death in the cell model (inhibitory effect; 27% in PFSE and 32% in piceatannol). Our study is the first to report that piceatannol‐rich PFSE can repress Aβ‐induced neuronal cell death by protecting against neurite fragmentation in the AD human cell model. These findings suggest that piceatannol‐rich PFSE can be considered a potentially neuroprotective functional food for both prevention and treatment of AD.

Circular RNA circ_0005835 promotes promoted neural stem cells proliferation and differentiate to neuron and inhibits inflammatory cytokines levels through miR-576-3p in Alzheimer's disease.

Alzheimer's disease (AD) is the most frequent neurodegenerative disease and it is difficult to have an effective and simple method for AD early diagnosis. CircRNAs (circular RNAs) are novel discovered non-coding endogenous RNAs that affect cell apoptosis, differentiation, growth, metabolism, and metastasis. Recently, it has reported that circ_0005835 was one upregulated circRNA in the AD patients. However, the function role of circ_0005835 remains unknown. In our study, we found that circ_0005835 was upregulated in AD patients and cell models. Knockdown of circ_0005835 could downregulate neuroinflammation in BV2 cells. Moreover, knockdown of circ_0005835 promoted neural stem cells (NSC) proliferation and differentiate to neuron. These data mean that circ_0005835 plays important role in the development of AD. The miR-576-3p expression in serum was downregulated in the AD group compared to the health control group. Consistently, the level of circ_0005835 was overexpressed in the Aβ-treated in both SH-SY5Y and BV2 cells. Moreover, the expression of miR-576-3p was negatively correlated with circ_0005835 in AD patients. In addition, we performed the rescued experiments to show that knockdown of circ_0005835 could downregulate neuroinflammation through sponging miR-576-3p in BV2 cells. Inhibition of circ_0005835 promoted NSC proliferation and differentiate to neuron via sponging miR-576-3p. These data suggested that circ_0005835 promoted AD development through regulating miR-576-3p expression.

Screening of the ubiquitin-proteasome system activators for anti-Alzheimer's disease by the high-content fluorescence imaging system.

Ubiquitin-proteasome system (UPS) plays an important role in neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). The discovery of UPS activators for anti-neurodegenerative diseases is becoming increasingly important. In this study, we aimed to identify potential UPS activators using the high-throughput screening method with the high-content fluorescence imaging system and validate the neuroprotective effect in the cell models of AD. At first, stable YFP-CL1 HT22 cells were successfully constructed by transfecting the YFP-CL1 plasmid into HT22 cells, together with G418 screening. The degradation activity of the test compounds via UPS was monitored by detecting the YFP fluorescence intensity reflected by the ubiquitin-proteasome degradation signal CL1. By employing the high-content fluorescence imaging system, together with stable YFP-CL1 HT22 cells, the UPS activators were successfully screened from our established TCM library. The representative images were captured and analyzed, and quantification of the YFP fluorescence intensity was performed by flow cytometry. Then, the neuroprotective effect of the UPS activators was investigated in pEGFP-N1-APP (APP), pRK5-EGFP-Tau P301L (Tau P301L), or pRK5-EGFP-Tau (Tau) transiently transfected HT22 cells using fluorescence imaging, flow cytometry, and Western blot. In conclusion, our study established a high-content fluorescence imaging system coupled with stable YFP-CL1 HT22 cells for the high-throughput screening of the UPS activators. Three compounds, namely salvianolic acid A (SAA), salvianolic acid B (SAB), and ellagic acid (EA), were identified to significantly decrease YFP fluorescence intensity, which suggested that these three compounds are UPS activators. The identified UPS activators were demonstrated to clear AD-related proteins, including APP, Tau, and Tau P301L. Therefore, these findings provide a novel insight into the discovery and development of anti-AD drugs.

Enhancing autophagy maturation with CCZ1-MON1A complex alleviates neuropathology and memory defects in Alzheimer disease models.

Rationale: Impairment of autophagy maturation has been implicated in Alzheimer's disease (AD) pathogenesis. However, the mechanism for this impairment has not been elucidated, and whether enhancing autophagy maturation is a viable therapeutic strategy for AD has not been verified.Methods: We examined the autophagosome maturation process in AD cell and mouse models by immunoblotting. To further understand the changes in autophagy in AD brains, we analyzed the transcriptome by RNA-sequencing and measured the expression of RAB7, CCZ1 and MON1A.We performed brain stereotaxic injections of AAV into 3xTg AD mouse brain and WT mouse brain to over-express MON1A/CCZ1 or knockdown MON1A. For in vitro studies, we purified autophagosomes, and determined GTP-RAB7 level in autophagosome fractions by GST-R7BD affinity-isolation assay.Results: We report that the active form of RAB7 was selectively decreased in autophagosome fractions isolated from cells and tissues of AD models, and that this decrease was accompanied by impaired activity of its guanine nucleotide exchange factor (GFE) CCZ1-MON1A. Overexpressing CCZ1-MON1A increased the active form of RAB7, enhanced autophagosome maturation, and promoted degradation of APP-CTFs, Aβ and P-tau in an autophagy-dependent manner in cells and a mouse AD model.Conclusions: Our data reveals that CCZ1-MON1A-RAB7 complex dysfunction is a potential mechanism for autophagosome maturation defects in AD, and advances the possibility that enhancing autophagosome maturation is a novel therapeutic strategy against AD.

Identification of potential hub genes of Alzheimer's disease by weighted gene co-expression network analysis

To investigate the differential expression gene modules and hub genes associated with Alzheimer's disease (AD) by weighted gene co-expression network analysis (WGCNA) and annotate the biological functions of these modules. We downloaded transcriptome sequencing data from the GEO database, and according to the correlation of the genes, a gene co-expression network was constructed with the parameter setting of β=8 and a correlation coefficient threshold of 0.85. Pearson correlation test was used to calculate the correlation between the module genes and clinical traits to screen the gene modules significantly associated with AD and identify the hub genes according to the connectivity within modules. GO functional enrichment analysis and KEGG pathway analysis were used to annotate the functions of the modules. A cell model of AD was established in SH-SY5Y cells by Aβ1-42 treatment, and the mRNA expression levels of the hub genes were compared between the Aβ1-42-treated cells and the control cells. Ten gene co-expression modules were constructed based on the correlations of gene expression, in which the brown (r=0.66, P < 0.001) and turquoise modules (r=-0.68, P < 0.001) were significantly correlated with the AD group. Forty-eight genes were identified as the hub genes in the co-expression network. Function annotation revealed that the genes in both modules were mainly enriched in DNA damage and repair pathways and metabolism-related pathways. Differential expression analysis of the genes revealed that the genes DNASE1, TEKT2 and MTSS1L were highly expressed while ACP2, LANCL2 and GMPR2 were lowly expressed in AD group. The results of cell experiment confirmed the up-regulation of DNASE1, TEKT2 and MTSS1L genes and the down-regulation of ACP2, LANCL2, and GMPR2 in Aβ1-42-treated SH-SY5Y cells (P < 0.01). The brown and turquoise modules are closely correlated with AD. The hub genes including MTSS1L, GMPR2, ACP2, ACTG1 and LANCL2 selected from the modules may participate in AD pathogenesis by regulating DNA damage and repair.

Insulin dysregulation as a prominent driver of cell cycle re-entry in Alzheimer's disease.

Cell Cycle Re-entry (CCR) is observed in several neurological disorders and contributes to cognitive impairment in the early stages. The CCR markers were monitored and correlated functionally with upregulation of Insulin Receptor (INSR) and Insulin like Growth factor 1 Receptor (IGF1R) in Alzheimer's Disease (AD) cell model and mouse brain tissue. The AD cell model was developed as per Majumder et al. (2019) and checked for Cyclin A, D and E Levels after 6 and 11 hours of model development in differentiated SHSY5Y cell line (with 10 µM RA and BDNF for cholinergic neuron like cells) by qPCR. We then checked for expression and activity of INSR and IGF1R in these cells and mouse brain (extracted from FFPE slides) through western blot and qPCR. To assess the correlation of the two events, we exploited overexpression based in-vitro studies for real-time assessment. Levels of INSR and IGF1R both increase on mRNA and protein levels in both cell and animal model. The cyclins A2, D and E however decline when the receptors are overexpressed in a serum free media for 6 hours and 11 hours. The time points were chosen to mimic the average mammalian cell cycle and showed that the upregulation of the receptors negatively impact and reduce cyclin D levels up to 4 fold whereas Cyclin A levels and Cyclin E levels are marginally reduced by 0.48 and 0.5 fold respectively. However, when stimulated with conventional ligands, Insulin and IGF1 or amyloid beta (1-42) the receptors positively correlate with the Cyclin levels. Western blots show that amyloid beta binding phosphorylates the pY1135/1136 of IGF1R, pY1150/1151 of INSR rather than conventional pY1158, 1162 and 1163. The reduction in conventional ligands, Insulin and IGF1 with ageing and build-up of amyloid beta which preferentially phosphorylates a different site could have implications that determines cellular fate after the re-entry. Reference: Majumder, P., Roy, K., Bagh, S. and Mukhopadhyay, D., 2019. Receptor tyrosine kinases (RTKs) consociate in regulatory clusters in Alzheimer's disease and type 2 diabetes. Molecular and cellular biochemistry, 459(1), pp.171-182.

Effect of active component compound of Epimedii Folium,Astragali Radix,and Puerariae Lobatae Radix on expression of ADAM17 in HT22 cells by mediating hepcidin

Alzheimer's disease(AD) patients in China have been surging, and the resultant medical burden and care demand have a huge impact on the development of individuals, families, and the society. The active component compound of Epimedii Folium, Astragali Radix, and Puerariae Lobatae Radix(YHG) can regulate the expression of iron metabolism-related proteins to inhibit brain iron overload and relieve hypofunction of central nervous system in AD patients. Hepcidin is an important target regulating iron metabolism. This study investigated the effect of YHG on the expression of a disintegrin and metalloprotease-17(ADAM17), a key enzyme in the hydrolysis of β amyloid precursor protein(APP) in HT22 cells, by mediating hepcidin. To be specific, HT22 cells were cultured in vitro, followed by liposome-mediated siRNA transfection to silence the expression of hepcidin. Real-time PCR and Western blot were performed to examine the silencing result and the effect of YHG on hepcidin in AD cell model. HT22 cells were randomized into 7 groups: control group, Aβ25-35 induction(Aβ) group, hepcidin-siRNA(siRNA) group, Aβ25-35 + hepcidin-siRNA(Aβ + siRNA) group, Aβ25-35+YHG(Aβ+YHG) group, hepcidin-siRNA+YHG(siRNA+YHG) group, Aβ25-35+hepcidin-siRNA+YHG(Aβ+siRNA+YHG) group. The expression of ADAM17 mRNA in cells was detected by real-time PCR, and the expression of ADAM17 protein by immunofluorescence and Western blot. Immunofluorescence showed that the ADAM17 protein expression was lower in the Aβ group, siRNA group, and Aβ+siRNA group than in the control group(P&lt;0.05) and the expression was lower in the Aβ+siRNA group(P&lt;0.05) and higher in the Aβ+YHG group(P&lt;0.05) than in the Aβ group. Moreover, the ADAM17 protein expression was lower in the Aβ+siRNA group(P&lt;0.05) and higher in the siRNA+YHG group(P&lt; 0.05) than in the siRNA group. The expression was higher in the Aβ+siRNA+YHG group than in the Aβ+siRNA group(P&lt;0.05). The results of Western blot and real-time PCR were consistent with those of immunofluorescence. The experiment showed that YHG induced hepcidin to up-regulate the expression of ADAM17 in AD cell model and promote the activation of non-starch metabolic pathways, which might be the internal mechanism of YHG in preventing and treating AD.

Thiamet G effects on mitochondria and AD pathological hallmarks in human iPSC derived models.

Thiamet-G (TMG) has recently been examined in human Alzheimer's Disease (AD) clinical trials. TMG increases total O-GlcNAc levels through inhibition of O-GlcNAcase (OGA). Modulation of OGA through genetic (overexpression or knockdown) or chemical means (TMG) has shown positive effects in transgenic AD animal models. Here, we sought to examine the effects of TMG and increased O-GlcNAc levels on induced pluripotent stem cell (iPSC) models of AD using both neurons and cerebral organoids. Human iPSCs were derived from the KU ADC fibroblast repository or obtained from WiCell. Twelve age and sex matched iPSC lines were used (6 non-demented/ND, 2 familial AD/FAD with APP V717I mutation, and 4 sporadic AD/SAD). Neurons or cerebral organoids were derived and matured from iPSCs using StemCell Technologies StemDiff protocols and reagents. iPSC derived neurons (iNeurons) and cerebral organoids were treated with 20 µM or 40 µM TMG for 14 days. Cell culture supernatants were collected and Aβ/sAPP measured. Protein lysates were used to measure O-GlcNAc, mitochondrial proteins, tau, and cell signaling proteins. Seahorse Bioanalyzer was used to measure oxygen consumption rates and fluorescent imaging for mitochondrial membrane potential, mitochondrial superoxide, and mitochondrial number/turnover. ND and SAD iNeurons treated with TMG had lower Aβ40 . SAD iNeurons had reduced Aβ42 with TMG treatment. PHF1 tau and total tau were increased in TMG treated SAD iNeurons. TMG treatment in ND and SAD iNeurons increased mitochondrial membrane potential and mitochondrial superoxide. TMG treatment increased mitochondrial mass for both new and old mitochondria in SAD iNeurons. In cerebral organoids, TMG treatment increased Aβ40 in ND and SAD samples, increased Aβ42 in SAD samples, and increased the ratio of Aβ42 / Aβ40 in ND and SAD samples. Overall, no changes were observed in FAD TMG treated iNeurons or cerebral organoids. Modulation of O-GlcNAc robustly effects AD pathological hallmarks and mitochondrial function in SAD but not FAD derived iNeurons and cerebral organoids. Further study is warranted to understand the mechanisms and lack of effect in FAD derived cell and organoid models.

Layer-by-layer self-assembly of hollow dextran sulfate/chitosan-coated zein nanoparticles loaded with crocin: Fabrication, structural characterization and potential biological fate

Crocin is a water-soluble carotenoid and has shown potential to improve the neurodegenerative disease such as Alzheimer's disease (AD). However, its application is limited due to the high instability and susceptibility to process conditions. Here, hollow dextran sulfate/chitosan (DS/CH)-coated zein nanoparticles (NPs) loaded with crocin using sodium carbonate as a sacrificing template were fabricated by a layer-by-layer (LbL) self-assembly technique. The mean particle size, polydispersity index (PDI), encapsulation efficiency, zeta potential, morphology (e.g. TEM and AFM), and FTIR observation revealed that the surface of crocin-loaded LbL hollow zein NPs was generated by the deposition of polyelectrolyte through electrostatic interactions, hydrogen bonding, and hydrophobic interactions. In vitro simulated gastrointestinal digestion and antioxidant activity assays indicated that the NPs exhibited better controlled release behavior and stronger antioxidant activity than that of uncoated crocin-loaded zein NPs dispersed in water. Moreover, the study of the potential effect of the NPs on AD cell model showed that the amyloid-β (Aβ1-42) concentration of differentiated SH-SY5Y cells decreased from 300 pg/mg to 170 pg/mg. These results reveal that LbL self-assembly of hollow DS/CH-coated zein NPs loaded with crocin can be developed as a promising delivery system for effective therapeutic approach of AD, and provide a new practical technique for delivering bioactive ingredients.

Chrysophanol exerts neuroprotective effects via interfering with endoplasmic reticulum stress apoptotic pathways in cell and animal models of Alzheimer's disease.

Chrysophanol (CHR), also well-known as Rhei radix et rhizome, is a crucial component in traditional Chinese medicine. It has been widely studied as a potential treatment for many diseases due to its anti-inflammatory effects. However, there are very few studies to establish the potential therapeutic effect of CHR in cell and animal models of Alzheimer's disease (AD). Therefore, we aim to investigate whether CHR could be used as a potential therapeutic approach to patients with AD and further disclose the underlying mechanism. Increasing studies have shown that endoplasmic reticulum (ER) calcium (Ca2+) homeostasis emerges as a central player in AD pathogenesis. Moreover, augmentation of ER stress (ERS) promotes neuronal apoptosis, and excessive oxidative stress is an inducer of ERS. Therefore, we believe that ERS-mediated apoptosis may be one of the causes of AD. This study examined the neuroprotective effects of CHR on AD rats and AD cell models and explored its potential mechanism. CHR could reduce the damage of neurons. In AD cell models, CHR significantly inhibited Aβ 25-35-induced neuronal damage, reduced the number of apoptotic cells and improved cell survival rate. Western blot showed that the expression of caspases 3, 9 and 12 was decreased after CHR treatment, and CHR also affected the ERS signalling pathway. In addition, the higher expression of pro-apoptotic proteins in the AD cell model was reduced after CHR treatment by inhibiting GRP78 signalling. Further studies have shown that overexpressed protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) inhibited the regulatory effect of CHR on PERK and weakened the neuroprotective effect of CHR on the AD cell model. This study revealed a novel mechanism through which CHR plays a neuroprotective role by regulating ERS when it comes to the therapy of AD.

Anti-PrP monoclonal antibody as a novel treatment for neurogenesis in mouse model of Alzheimer's disease.

BackgroundAlzheimer's disease (AD) is the most common degenerative disease characterized by cognitive impairment, memory decline, and language disorder for which there is no effective treatment. Neurogenesis has been indicated in AD and may play an important role in the pathogenesis of AD. Targeting this pathway is a new idea for the treatment of the disease. A recent study reveals that the cellular prion protein (PrP), a receptor for Aβ oligomers, regulates neurogenesis, and its elevated expression is related to cell differentiation. The aim of the present study was to investigate the neuroprotective effects of 6D11 (PrP monoclonal antibody) via neurogenesis promotion in APP/PS1 transgenic mice and Aβ‐induced cell model of AD.MethodsIn the present study, 9‐month‐old male APP/PS1 mice were injected with 6D11. Then, the Morris water maze was used to examine the spatial learning and memory abilities of the mice in both groups, and immunostained was used to assess the level of Aβ, neurogenesis, and neural stem cells (NSCs) differentiation.Results6D11 attenuated cognitive deficits in APP/PS1 transgenic mice, which was accompanied by a decrease of the deposition of Aβ. In addition, 6D11 treatment promoted differentiation of the existing hippocampal cells to neurons.ConclusionsOur findings confirmed that 6D11 has a therapeutic effect in APP/PS1 transgenic AD mouse model and Aβ‐induced AD cell model, and the effect exerted via increase of neurogenesis and cell differentiation by transduction of Aβ peptide signal.

Evidence-based complementary and alternative medicine bioinformatics approach through network pharmacology and molecular docking to determine the molecular mechanisms of Erjing pill in Alzheimer's disease.

Erjing pill, a Traditional Chinese Medicine (TCM) formulation composed of Polygonatum sibiricum and Lycium chinense, has an important role in the treatment of Alzheimer's disease (AD). However, the underlying mechanisms of the action of Erjing pill in AD have remained elusive. In the present study, the key ingredients of Erjing pill were investigated and the active components and their mechanisms of action on AD were analyzed based on networks pharmacology. By using the TCM and TCM Systems Pharmacology and databases, the components of Erjing pill were screened and the data were captured using Discovery Studio. The SwissTarget webserver database was used to predict the potential protein targets of Erjing pill components for pathologies related to AD. The data were further analyzed with the disease targets of AD based on analysis of the Online Mendelian Inheritance in Man, DiGSeE and Therapeutic Target Database. Subsequent analysis of mechanistic pathways of the screened components and protein targets allowed us to construct a network by using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, which revealed potential molecular mechanisms of Erjing pill against AD. Finally, the protective effect of three active components on neurons was verified using an in vitro injury model of PC12 cells induced by Aβ25-35. The results indicated that 65 bioactive components of Erjing pill, including lauric acid and zederone, and 6 targets, including acetylcholinesterase, butylcholinesterase and amyloid protein precursor, were closely associated with the prevention and treatment of AD. The molecular components of Erjing pill were indicated to be involved in various biological signaling processes, mainly in synaptic signal transmission, transsynaptic signal transmission and chemical synaptic transmission. Furthermore, related pathways targeted by Erjing pill in AD included the regulation of neuroactive ligand-receptor interactions, the PI3K-Akt signaling pathway, serotoninergic synapses, calcium signaling pathways and dopaminergic synapses. A cell viability assay indicated that the compounds (polygonatine A, polygonatine C and 4',5-dihydroxyflavone) assessed were able to significantly improve the survival rate and increase the Ca2+ level in a PC12 cell model of AD induced by amyloid-β25-35. The present study revealed that the mechanisms of action of Erjing pill to prevent and treat AD included a multicompound, multitarget and multipathway regulatory network.

Curcumin Alleviates Aβ42-Induced Neuronal Metabolic Dysfunction via the Thrb/SIRT3 Axis and Improves Cognition in APPTG Mice.

Curcumin has been reported to have a therapeutic effect on Alzheimer's disease (AD), but the specific mechanism remains to be elucidated. In the present research, we aimed to investigate the effect and molecular mechanism of curcumin on AD. Mouse primary hippocampal neuron cells were treated with various concentrations of beta-amyloid 42 (Aβ42) and the results found that Aβ42 inhibited cell viability in a dose-dependent manner. Compared with 50ng/mL Aβ42, 500ng/mL Aβ42 could further promote cell apoptosis, reduce the ratio of Nicotinamide adenine dinucleotide (NAD(+))/Nicotinamide adenine diphosphate hydride (NADH) and Adenosine 5'-triphosphate (ATP) level, and inhibit Sirtuins 3 (SIRT3) deacetylation activity and protein expression of Thyroid hormone receptor beta (Thrb) and SIRT3. Hence, 500ng/mL Aβ42 was used to establish a cell model of AD. Curcumin significantly reversed the inhibitory effects of Aβ42 on cell viability, SIRT3 deacetylation activity, the ratio of NAD+/NADH, ATP level and the protein expression of Thrb and SIRT3, and the promotive effect on apoptosis. ChIPBase was used to predict the binding region of Thrb and SIRT3. Dual luciferase reporter gene and Chromatin immune precipitation (ChIP) assays were employed to verify the relationship between Thrb and promoter of SIRT3 mRNA. Overexpression of Thrb recovered Aβ42 induced metabolic dysfunction, while Thrb silence aggravated Aβ42 induced metabolic dysfunction. Moreover, Thrb silence or 3-TYP (a selective inhibitor of SIRT3) treatment abolished the amelioration of curcumin on Aβ42 induced metabolic dysfunction. Additionally, curcumin attenuated memory deficits in Amyloid precursor protein transgenic (APPTG) mice. Collectively, curcumin alleviated Aβ42-induced neuronal metabolic dysfunction through increasing Thrb expression and SIRT3 activity and improved cognition in APPTG mice.

Functional effects of berberine in modulating mitochondrial dysfunction and inflammatory response in the respective amyloidogenic cells and activated microglial cells – In vitro models simulating Alzheimer's disease pathology

AimBerberine (BBR) is an alkaloid extracted from Coptidis Rhizoma, also known as Huang-Lian. Huang-Lian has been used extensively in traditional Chinese medicine for the treatment of various diseases, including diabetes and dementia. Because Alzheimer's disease (AD) is a complex disease that involves various pathophysiological changes, the diverse neuroprotective effects of BBR may be useful for improving the brain's energy state at an early stage of the disease. Main methodsWe performed extracellular flux and 1H NMR-based metabolic profiling analyses to investigate the effects of BBR on metabolic processes in these cells. Pioglitazone (PIO), a peroxisome proliferator-activated receptor-γ (PPARγ) agonist has been studied extensively for the treatment of AD. We explored the combination dosing effects of BBR and PIO in vitro, then leveraged computational methods to explain the experimental finding. Key findingsBBR demonstrates potential in modulating the mitochondrial bioenergetics and attenuating dysfunction of the primary energy and glutathione metabolism pathways in an AD cell model. It also suppresses basal respiration and reduces the production of pro-inflammatory cytokines in activated microglial cells. Both experimental and computational observations indicate that BBR and PIO have comparable binding affinities to the PPARγ protein, suggesting both drugs may have some overlapping effects for AD. SignificanceBBR exerts beneficial effects on disrupted metabolic processes in amyloidogenic cells and activated microglial cells, which are important for preventing or delaying early-stage disease progression. The choice of BBR or PIO for AD treatment depends on their respective pharmacokinetic profiles, delivery, efficacy and safety, and warrants further study.

Formulated Chinese medicine Shaoyao Gancao Tang reduces NLRP1 and NLRP3 in Alzheimer's disease cell and mouse models for neuroprotection and cognitive improvement.

Amyloid β (Aβ) plays a major role in the neurodegeneration of Alzheimer’s disease (AD). The accumulation of misfolded Aβ causes oxidative stress and inflammatory damage leading to apoptotic cell death. Traditional Chinese herbal medicine (CHM) has been widely used in treating neurodegenerative diseases by reducing oxidative stress and neuroinflammation. We examined the neuroprotective effect of formulated CHM Shaoyao Gancao Tang (SG-Tang, made of Paeonia lactiflora and Glycyrrhiza uralensis at 1:1 ratio) in AD cell and mouse models. In Aβ-GFP SH-SY5Y cells, SG-Tang reduced Aβ aggregation and reactive oxygen species (ROS) production, as well as improved neurite outgrowth. When the Aβ-GFP-expressing cells were stimulated with conditioned medium from interferon (IFN)-γ-activated HMC3 microglia, SG-Tang suppressed expressions of inducible nitric oxide synthase (iNOS), NLR family pyrin domain containing 1 (NLRP1) and 3 (NLRP3), tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, attenuated caspase-1 activity and ROS production, and promoted neurite outgrowth. In streptozocin-induced hyperglycemic APP/PS1/Tau triple transgenic (3×Tg-AD) mice, SG-Tang also reduced expressions of NLRP1, NLRP3, Aβ and Tau in hippocampus and cortex, as well as improved working and spatial memories in Y maze and Morris water maze. Collectively, our results demonstrate the potential of SG-Tang in treating AD by moderating neuroinflammation.