The accumulation and spread of prion-like proteins is a key feature of neurodegenerative diseases (NDs) such as Alzheimer's disease, Parkinson's disease, or Amyotrophic Lateral Sclerosis. In a process known as 'seeding', prion-like proteins such as amyloid beta, microtubule-associated protein tau, α-synuclein, silence superoxide dismutase 1, or transactive response DNA-binding protein 43 kDa, propagate their misfolded conformations by transforming their respective soluble monomers into fibrils. Cellular and molecular evidence of prion-like propagation in NDs, the clinical relevance of their 'seeding' capacities, and their levels of contribution towards disease progression have been intensively studied over recent years. This review unpacks the cyclic prion-like propagation in cells including factors of aggregate internalization, endo-lysosomal leaking, aggregate degradation, and secretion. Debates on the importance of the role of prion-like protein aggregates in NDs, whether causal or consequent, are also discussed. Applications lead to a greater understanding of ND pathogenesis and increased potential for therapeutic strategies.
Humans ; Prions ; Neurodegenerative Diseases/pathology* ; Amyloid beta-Peptides ; Alzheimer Disease ; alpha-Synuclein ; tau Proteins ; Parkinson Disease

Silent information regulator 1 (SIRT1) is one of the seven mammalian proteins of the sirtuin family of NAD⁺-dependent deacetylases. SIRT1 plays a pivotal role in neuroprotection and ongoing research has uncovered a mechanism by which SIRT1 may exert a neuroprotective effect on Alzheimer's disease (AD). Growing evidence demonstrates that SIRT1 regulates many pathological processes including amyloid-β precursor protein (APP) processing, neuroinflammation, neurodegeneration, and mitochondrial dysfunction. SIRT1 has recently received enormous attention, and pharmacological or transgenic approaches to activate the sirtuin pathway have shown promising results in the experimental models of AD. In the present review, we delineate the role of SIRT1 in AD from a disease-centered perspective and provides an up-to-date overview of the SIRT1 modulators and their potential as effective therapeutics in AD.
Animals ; Alzheimer Disease ; Amyloid beta-Protein Precursor ; Animals, Genetically Modified ; Sirtuin 1 ; Sirtuins ; Humans

This study employed bibliometrics tools to review the studies of traditional Chinese medicine(TCM) treatment of Alzheimer's disease(AD) in recent ten years, aiming to explore the research status, hotspots, and future trends in this field at home and abroad. The relevant literature published from January 1, 2012 to August 15, 2022 was retrieved from Web of Science and CNKI. CiteSpace 6.1R2 and VOSviewer 1.6.15 were used for the visual analysis of authors, countries, institutions, keywords, journals, etc. A total of 2 254 Chinese articles and 545 English articles were included. The annual number of articles published showed a rising trend with fluctuations. The country with the largest number of relevant articles published and the largest centrality was China. SUN Guo-jie and WANG Qi were the authors publishing the most Chinese articles and English articles, respectively. Hubei University of Chinese Medicine and Beijing University of Chinese Medicine published the most articles in Chinese and English, respectively. Journal of Ethnopharmacology and Neuroscience Letters published the articles with the highest cited frequency and the highest centrality. According to the keywords, the research on TCM treatment of AD mainly focused on the mechanism of action and treatment methods. Metabolomics, intestinal flora, oxidative stress, tau hyperphosphorylation, β-amyloid(Aβ), inflammatory cytokines, and autophagy were the focuses of the research on mechanism of action. Acupuncture, clinical effect, kidney deficiency and phlegm stasis, and dredging governor vessel to revitalize mind were the hotspots of clinical research. This research field is still in the stage of exploration and development. Exchanges and cooperation among institutions should be encouraged to carry out more high-quality basic research on TCM treatment of AD, obtain high-level evidence, and clarify the pathogenesis and prescription mechanism.
Humans ; Alzheimer Disease/drug therapy* ; Medicine, Chinese Traditional ; Acupuncture Therapy ; Medicine ; Amyloid beta-Peptides

The extracellular domain (p75ECD) of p75 neurotrophin receptor (p75NTR) antagonizes Aβ neurotoxicity and promotes Aβ clearance in Alzheimer's disease (AD). The impaired shedding of p75ECD is a key pathological process in AD, but its regulatory mechanism is largely unknown. This study was designed to investigate the presence and alterations of naturally-occurring autoantibodies against p75ECD (p75ECD-NAbs) in AD patients and their effects on AD pathology. We found that the cerebrospinal fluid (CSF) level of p75ECD-NAbs was increased in AD, and negatively associated with the CSF levels of p75ECD. Transgenic AD mice actively immunized with p75ECD showed a lower level of p75ECD and more severe AD pathology in the brain, as well as worse cognitive functions than the control groups, which were immunized with Re-p75ECD (the reverse sequence of p75ECD) and phosphate-buffered saline, respectively. These findings demonstrate the impact of p75ECD-NAbs on p75NTR/p75ECD imbalance, providing a novel insight into the role of autoimmunity and p75NTR in AD.
Mice ; Animals ; Alzheimer Disease/pathology* ; Receptor, Nerve Growth Factor ; Amyloid beta-Peptides ; Autoantibodies ; Mice, Transgenic

OBJECTIVE: To explore the specific pharmacological molecular mechanisms of Kai Xin San (KXS) on treating Alzheimer's disease (AD) based on network pharmacology and experimental validation. METHODS: The chemical compounds of KXS and their corresponding targets were screened using the Encyclopedia of Traditional Chinese Medicine (ETCM) database. AD-related target proteins were obtained from MalaCards database and DisGeNET databases. Key compounds and targets were identified from the compound-target-disease network and protein-protein interaction (PPI) network analysis. Functional enrichment analysis predicted the potential key signaling pathways involved in the treatment of AD with KXS. The binding affinities between key ingredients and targets were further verified using molecular docking. Finally, the predicted key signaling pathway was validated experimentally. Positioning navigation and space search experiments were conducted to evaluate the cognitive improvement effect of KXS on AD rats. Western blot was used to further examine and investigate the expression of the key target proteins related to the predicted pathway. RESULTS: In total, 38 active compounds and 469 corresponding targets of KXS were screened, and 264 target proteins associated with AD were identified. The compound-target-disease and PPI networks identified key active ingredients and protein targets. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested a potential effect of KXS in the treatment of AD via the amyloid beta (A β)-glycogen synthase kinase-3 beta (GSK3 β)-Tau pathway. Molecular docking revealed a high binding affinity between the key ingredients and targets. In vivo, KXS treatment significantly improved cognitive deficits in AD rats induced by Aβ_1-42, decreased the levels of Aβ, p-GSK3β, p-Tau and cyclin-dependent kinase 5, and increased the expressions of protein phosphatase 1 alpha (PP1A) and PP2A (P<0.05 or P<0.01). CONCLUSION KXS exerted neuroprotective effects by regulating the Aβ -GSK3β-Tau signaling pathway, which provides novel insights into the therapeutic mechanism of KXS and a feasible pharmacological strategy for the treatment of AD.
Rats ; Animals ; Alzheimer Disease/drug therapy* ; Amyloid beta-Peptides ; Glycogen Synthase Kinase 3 beta ; Network Pharmacology ; Molecular Docking Simulation ; Glycogen Synthase Kinase 3/therapeutic use* ; Drugs, Chinese Herbal/therapeutic use*

OBJECTIVE: To investigate the molecular mechanisms underlying the beneficial effect of electroacupuncture (EA) in experimental models of Alzheimer's disease (AD) in vivo. METHODS: Senescence-accelerated mouse prone 8 (SAMP8) mice were used as AD models and received EA at Yingxiang (LI 20, bilateral) and Yintang (GV 29) points for 20 days. For certain experiments, SAMP8 mice were injected intravenously with human fibrin (2 mg). The Morris water maze test was used to assess cognitive and memory abilities. The changes of tight junctions of blood-brain barrier (BBB) in mice were observed by transmission electron microscope. The expressions of fibrin, amyloid- β (Aβ), and ionized calcium-binding adapter molecule 1 (IBa-1) in mouse hippocampus (CA1/CA3) were detected by reverse transcription-quantitative polymerase chain reaction (qRT-PCR), Western blot or immunohistochemical staining. The expression of fibrin in mouse plasma was detected by enzyme-linked immunosorbent assay. The expressions of tight junction proteins zonula occludens-1 and claudin-5 in hippocampus were detected by qRT-PCR and immunofluorescence staining. Apoptosis of hippocampal neurons was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. RESULTS: Fibrin was time-dependently deposited in the hippocampus of SAMP8 mice and this was inhibited by EA treatment (P<0.05 or P<0.01). Furthermore, EA treatment suppressed the accumulation of Aβ in the hippocampus of SAMP8 mice (P<0.01), which was reversed by fibrin injection (P<0.05 or P<0.01). EA improved SAMP8 mice cognitive impairment and BBB permeability (P<0.05 or P<0.01). Moreover, EA decreased reactive oxygen species levels and neuroinflammation in the hippocampus of SAMP8 mice, which was reversed by fibrin injection (P<0.05 or P<0.01). Mechanistically, EA inhibited the promoting effect of fibrin on the high mobility group box protein 1 (HMGB1)/toll-like receptor 4 (TLR4) and receptor for advanced glycation end products (RAGE)/nicotinamide adenine dinucleotide phosphate (NADPH) signaling pathways (P<0.01). CONCLUSION EA may potentially improve cognitive impairment in AD via inhibition of fibrin/A β deposition and deactivation of the HMGB1/TLR4 and RAGE/NADPH signaling pathways.
Mice ; Humans ; Animals ; NADP/metabolism* ; Toll-Like Receptor 4 ; HMGB1 Protein/metabolism* ; Receptor for Advanced Glycation End Products/metabolism* ; Blood-Brain Barrier/metabolism* ; Neuroinflammatory Diseases ; Electroacupuncture ; Alzheimer Disease/therapy* ; Hippocampus/metabolism* ; Amyloid beta-Peptides/metabolism*

Mutations in genes encoding amyloid precursor protein (APP) and presenilins (PSs) cause familial forms of Alzheimer's disease (AD), a neurodegenerative disorder strongly associated with aging. It is currently unknown whether and how AD risks affect early brain development, and to what extent subtle synaptic pathology may occur prior to overt hallmark AD pathology. Transgenic mutant APP/PS1 over-expression mouse lines are key tools for studying the molecular mechanisms of AD pathogenesis. Among these lines, the 5XFAD mice rapidly develop key features of AD pathology and have proven utility in studying amyloid plaque formation and amyloid β (Aβ)-induced neurodegeneration. We reasoned that transgenic mutant APP/PS1 over-expression in 5XFAD mice may lead to neurodevelopmental defects in early cortical neurons, and performed detailed synaptic physiological characterization of layer 5 (L5) neurons from the prefrontal cortex (PFC) of 5XFAD and wild-type littermate controls. L5 PFC neurons from 5XFAD mice show early APP/Aβ immunolabeling. Whole-cell patch-clamp recording at an early post-weaning age (P22-30) revealed functional impairments; although 5XFAD PFC-L5 neurons exhibited similar membrane properties, they were intrinsically less excitable. In addition, these neurons received smaller amplitude and frequency of miniature excitatory synaptic inputs. These functional disturbances were further corroborated by decreased dendritic spine density and spine head volumes that indicated impaired synapse maturation. Slice biotinylation followed by Western blot analysis of PFC-L5 tissue revealed that 5XFAD mice showed reduced synaptic AMPA receptor subunit GluA1 and decreased synaptic NMDA receptor subunit GluN2A. Consistent with this, patch-clamp recording of the evoked L23>L5 synaptic responses revealed a reduced AMPA/NMDA receptor current ratio, and an increased level of AMPAR-lacking silent synapses. These results suggest that transgenic mutant forms of APP/PS1 overexpression in 5XFAD mice leads to early developmental defects of cortical circuits, which could contribute to the age-dependent synaptic pathology and neurodegeneration later in life.
Mice ; Animals ; Alzheimer Disease/pathology* ; Amyloid beta-Peptides/metabolism* ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Amyloid beta-Protein Precursor/metabolism* ; Mice, Transgenic ; Neurons/metabolism* ; Receptors, AMPA/metabolism* ; Disease Models, Animal

Humans ; Alzheimer Disease ; Amyloid beta-Peptides ; Neurons ; Lysosomes ; Hydrogen-Ion Concentration

Resveratrol (RES), a natural polyphenolic phytochemical, has been suggested as a putative anti-aging molecule for the prevention and treatment of Alzheimer's disease (AD) by the activation of sirtuin 1 (Sirt1/Sir2). In this study, we tested the effects of RES and Sirt1/Sir2 on sleep and courtship memory in a Drosophila model by overexpression of amyloid precursor protein (APP), whose duplications and mutations cause familial AD. We found a mild but significant transcriptional increase of Drosophila Sir2 (dSir2) by RES supplementation for up to 17 days in APP flies, but not for 7 days. RES and dSir2 almost completely reversed the sleep and memory deficits in APP flies. We further demonstrated that dSir2 acts as a sleep promotor in Drosophila neurons. Interestingly, RES increased sleep in the absence of dSir2 in dSir2-null mutants, and RES further enhanced sleep when dSir2 was either overexpressed or knocked down in APP flies. Finally, we showed that Aβ aggregates in APP flies were reduced by RES and dSir2, probably via inhibiting Drosophila β-secretase (dBACE). Our data suggest that RES rescues the APP-induced behavioral deficits and Aβ burden largely, but not exclusively, via dSir2.
Animals ; Alzheimer Disease/metabolism* ; Amyloid beta-Peptides ; Amyloid beta-Protein Precursor/metabolism* ; Drosophila/physiology* ; Drosophila Proteins/metabolism* ; Resveratrol/pharmacology* ; Sirtuin 1 ; Sleep

Humans ; Alzheimer Disease/genetics* ; Apolipoprotein E4/genetics* ; Amyloid beta-Peptides