Reduced Aβ Plaque Research Articles

Advances in Alzheimer's Disease-Associated Aβ Therapy Based on Peptide.

Alzheimer's disease (AD) urgently needs innovative treatments due to the increasing aging population and lack of effective drugs and therapies. The amyloid fibrosis of AD-associated β-amyloid (Aβ) that could induce a series of cascades, such as oxidative stress and inflammation, is a critical factor in the progression of AD. Recently, peptide-based therapies for AD are expected to be great potential strategies for the high specificity to the targets, low toxicity, fast blood clearance, rapid cell and tissue permeability, and superior biochemical characteristics. Specifically, various chiral amino acids or peptide-modified interfaces draw much attention as effective manners to inhibit Aβ fibrillation. On the other hand, peptide-based inhibitors could be obtained through affinity screening such as phage display or by rational design based on the core sequence of Aβ fibrosis or by computer aided drug design based on the structure of Aβ. These peptide-based therapies can inhibit Aβ fibrillation and reduce cytotoxicity induced by Aβ aggregation and some have been shown to relieve cognition in AD model mice and reduce Aβ plaques in mice brains. This review summarizes the design method and characteristics of peptide inhibitors and their effect on the amyloid fibrosis of Aβ. We further describe some analysis methods for evaluating the inhibitory effect and point out the challenges in these areas, and possible directions for the design of AD drugs based on peptides, which lay the foundation for the development of new effective drugs in the future.

Administration of recombinant FOXN1 protein attenuates Alzheimer’s pathology in mice

BackgroundAlzheimer’s disease (AD) is the most common cause of dementia in older adults and characterized by progressive loss of memory and cognitive functions that are associated with amyloid-beta (Aβ) plaques and neurofibrillary tangles. Immune cells play an important role in the clearance of Aβ deposits and neurofibrillary tangles. T cells are the major component of the immune system. The thymus is the primary organ for T cell generation. T cell development in the thymus depends on thymic epithelial cells (TECs). However, TECs undergo both qualitative and quantitative loss over time. We have previously reported that a recombinant (r) protein containing FOXN1 and a protein transduction domain can increase the number of TECs and subsequently increases the number of T cells in mice. In this study we determined the ability of rFOXN1 to affect cognitive performance and AD pathology in mice. MethodsAged 3xTg-AD and APP/PS1 AD mice were injected with rFOXN1 or control protein. Cognitive performance, AD pathology, the thymic microenvironment and immune cells were then analyzed. ResultsAdministration of rFOXN1 into AD mice improves cognitive performance and reduces Aβ plaque load and phosphorylated tau in the brain. This is related to rejuvenating the aged thymic microenvironment, which results in enhanced T cell generation in the thymus, leading to increased number of T cells, especially IFNγ-producing T cells, in the spleen and the choroid plexus (CP), enhanced expression of immune cell trafficking molecules in the CP, and increased migration of monocyte-derived macrophages into the brain. Furthermore, the production of anti-Aβ antibodies in the serum and the brain, and the macrophage phagocytosis of Aβ are enhanced in rFOXN1-treated AD mice. ConclusionsOur results suggest that rFOXN1 protein has the potential to provide a novel approach to treat AD patients.

Early tactile stimulation influences the development of Alzheimer's disease in gestationally stressed APP NL-G-F adult offspring NL-G-F/NL-G-F mice

Alzheimer's disease (AD) is associated with cerebral plaques and tangles, reduced synapse number, and shrinkage in several brain areas and these morphological effects are associated with the onset of compromised cognitive, motor, and anxiety-like behaviours. The appearance of both anatomical and behavioural symptoms is worsened by stress. The focus of this study was to examine the effect of neonatal tactile stimulation on AD-like behavioural and neurological symptoms on APP NL-G-F/NL-G-F mice, a mouse model of AD, who have been gestationally stressed. Our findings indicate that neonatal tactile stimulation improves cognition, motor skills, and anxiety-like symptoms in both gestationally stressed and non-stressed adult APP mice and that these alterations are associated with reduced Aβ plaque formation. Thus, tactile stimulation appears to be a promising non-invasive preventative strategy for slowing the onset of dementia in aging animals.

Ogt-mediated O-GlcNAcylation inhibits astrocytes activation through modulating NF-κB signaling pathway

Previous studies have shown that Ogt-mediated O-GlcNAcylation is essential for neuronal development and function. However, the function of O-GlcNAc transferase (Ogt) and O-GlcNAcylation in astrocytes remains largely unknown. Here we show that Ogt deficiency induces inflammatory activation of astrocytes in vivo and in vitro, and impairs cognitive function of mice. The restoration of O-GlcNAcylation via GlcNAc supplementation inhibits the activation of astrocytes, inflammation and improves the impaired cognitive function of Ogt deficient mice. Mechanistically, Ogt interacts with NF-κB p65 and catalyzes the O-GlcNAcylation of NF-κB p65 in astrocytes. Ogt deficiency induces the activation of NF-κB signaling pathway by promoting Gsk3β binding. Moreover, Ogt depletion induces the activation of astrocytes derived from human induced pluripotent stem cells. The restoration of O-GlcNAcylation inhibits the activation of astrocytes, inflammation and reduces Aβ plaque of AD mice in vitro and in vivo. Collectively, our study reveals a critical function of Ogt-mediated O-GlcNAcylation in astrocytes through regulating NF-κB signaling pathway.

BMD‐001, a nanoparticle containing miR‐485‐3p antisense oligonucleotide, blocks Alzheimer's disease progression

AbstractBackgroundAlzheimer’s disease (AD) is a form of dementia characterized by progressive memory decline and cognitive dysfunction, which affects more than 44 million people worldwide. Currently, there is no effective therapy for AD despite its increasing global incidence; thus, effective treatment strategies for AD are urgently needed.MethodIn a previous report, we confirmed that expression of miR‐485‐3p was increased in the brain tissues, CSF, and plasma exosomes of AD patients than in healthy controls. In addition, the therapeutic potential of downregulation of miR‐485‐3p was also shown in 5XFAD AD model mice. Based on this target validation, we developed a nanoparticle containing antisense oligonucleotide (ASO) targeting miR‐485‐3p, named BMD‐001, which has a high CNS‐targeting ability to cross the blood‐brain barrier (BBB). BMD‐001 was injected into 10‐month‐old 5XFAD mice by intravenous injection, once weekly for four weeks. Behavioral tests were performed at 11 months and their brain pathology was examined after 8‐week‐washout at 13 months.ResultTo evaluate in vivo pharmacokinetics of BMD‐001, the plasma levels of Cy5‐labeled ASO encapsulated in the nanoparticle were measured after intravenous injection along with a naked ASO without formulation of nanoparticle. The half‐life of the ASO in the nanoparticle was 93 min while that of the naked ASO was only 43 sec. Furthermore, we also observed that the brain accumulation of the fluorescent ASO in the nanoparticle was 64‐fold higher than the naked ASO and was maintained up to 16 hours, as monitored by in vivo imaging. After BMD‐001 injection, miR‐485‐3p expression was decreased in the brain tissue. We found that BMD‐001 enhanced Aβ clearance via phagocytosis of Aβ in vitro and in vivo. Furthermore, BMD‐001 reduced Aβ plaques, tau pathology, inflammasome, neuroinflammation, and cognitive decline in the 5XFAD mice.ConclusionCollectively, our findings suggest that BMD‐001 is delivered to the brain through the efficient BBB penetration. Furthermore, BMD‐001 can be a promising candidate for treatment of AD pathology and cognitive decline, establishing a new paradigm in the AD field.

Secreted endogenous macrosomes reduce Aβ burden and ameliorate Alzheimer's disease.

Innovative therapeutic strategies are urgently needed for Alzheimer's disease (AD) due to the increasing size of the aging population and the lack of effective drug treatment. Here, we report the therapeutic effects of extracellular vesicles (EVs) secreted by microglia, including macrosomes and small EVs, on AD-associated pathology. Macrosomes strongly inhibited β-amyloid (Aβ) aggregation and rescued cells from Aβ misfolding-induced cytotoxicity. Furthermore, macrosome administration reduced Aβ plaques and ameliorated cognitive impairment in mice with AD. In contrast, small EVs slightly promoted Aβ aggregation and did not improve AD pathology. Proteomic analysis of small EVs and macrosomes revealed that macrosomes harbor several important neuroprotective proteins that inhibit Aβ misfolding. In particular, the small integral membrane protein 10-like protein 2B in macrosomes has been shown to inhibit Aβ aggregation. Our observations provide an alternative therapeutic strategy for the treatment of AD over conventional ineffective drug treatments.

Geraniol improves passive avoidance memory and hippocampal synaptic plasticity deficits in a rat model of Alzheimer's disease

Alzheimer's disease (AD) is the most progressive and irreversible neurodegenerative disease that leads to synaptic loss and cognitive decline. The present study was designed to evaluate the effects of geraniol (GR), a valuable acyclic monoterpene alcohol, with protective and therapeutic effects, on passive avoidance memory, hippocampal synaptic plasticity, and amyloid-beta (Aβ) plaques formation in an AD rat model induced by intracerebroventricular (ICV) microinjection of Aβ1-40. Seventy male Wistar rats were randomly into sham, control, control-GR (100 mg/kg; P.O. (orally), AD, GR-AD (100 mg/kg; P.O.; pretreatment), AD-GR (100 mg/kg; P.O.; treatment), and GR-AD-GR (100 mg/kg; P.O.; pretreatment & treatment). Administration of GR was continued for four consecutive weeks. Training for the passive avoidance test was carried out on the 36th day and a memory retention test was performed 24 h later. On day 38, hippocampal synaptic plasticity (long-term potentiation; LTP) was recorded in perforant path-dentate gyrus (PP-DG) synapses to assess field excitatory postsynaptic potentials (fEPSPs) slope and population spike (PS) amplitude. Subsequently, Aβ plaques were identified in the hippocampus by Congo red staining. The results showed that Aβ microinjection increased passive avoidance memory impairment, suppressed of hippocampal LTP induction, and enhanced of Aβ plaque formation in the hippocampus. Interestingly, oral administration of GR improved passive avoidance memory deficit, ameliorated hippocampal LTP impairment, and reduced Aβ plaque accumulation in the Aβ-infused rats. The results suggest that GR mitigates Aβ-induced passive avoidance memory impairment, possibly through alleviation of hippocampal synaptic dysfunction and inhibition of Aβ plaque formation.

Multiple effects of polydopamine nanoparticles on Cu2+-mediated Alzheimer's β-amyloid aggregation

• PDA NPs change Cu 2+ -mediated Aβ aggregation pathway by chelating Cu 2+. • PDA NPs remove ROS and rescue damaged cells. • NIR photothermal effect of PDA NPs promotes degrading Aβ 42 -Cu 2+ complexes. • PDA NPs reduce Aβ plaques and prolong the lifespan of AD nematodes. Deposition of β-amyloid protein (Aβ) is the main hallmark of Alzheimer's disease (AD), and it has been well recognized that Cu 2+ -mediated Aβ aggregation plays a crucial role in AD pathological processes. Cu 2+ binding to Aβ can promote the production of reactive oxygen species (ROS) through Fenton-like reactions and produce more toxic Aβ-Cu 2+ species under Cu 2+ stimulation. Thus, the development of nanomaterials that can inhibit Cu 2+ -mediated Aβ aggregation and degrade Aβ-Cu 2+ complexes is considered an effective strategy for the prevention and treatment of AD. In this study, polydopamine nanoparticles (PDA NPs) were prepared and the results reveal that PDA NPs potently inhibit Cu 2+ -mediated Aβ aggregation and effectively reduce the formation of Aβ-Cu 2+ complexes. In vitro experiments show that PDA NPs efficiently eliminate ROS generation catalyzed by Cu 2+ or Aβ-Cu 2+ complexes, thus rescuing cultured cells by reducing intracellular ROS levels. More importantly, PDA NPs can depolymerize Aβ-Cu 2+ complexes, and the degradation of Aβ-Cu 2+ complexes is promoted by near-infrared light irradiation due to their high photothermal conversion ability. In vivo studies reveal that PDA NPs significantly reduce the deposition of Aβ plaques in the presence of Cu 2+ and extend the lifespan of AD nematodes from 11 to 14 d. Thus, the PDA NPs developed herein are multifunctional against Cu 2+ -mediated Aβ aggregation for the potential prevention and treatment of AD.

Development and Evaluation of Solid Lipid Nanoparticles for the Clearance of Aβ in Alzheimer’s Disease

Aggregation of Amyloid-β (Aβ) leads to the formation and deposition of neurofibrillary tangles and plaques which is the main pathological hallmark of Alzheimer's disease (AD). The bioavailability of the drugs and their capability to cross the BBB plays a crucial role in the therapeutics of AD. The present study evaluates the Memantine Hydrochloride (MeHCl) and Tramiprosate (TMPS) loaded solid lipid nanoparticles (SLNs) for the clearance of Aβ on SHSY5Y cells in rat hippocampus. Molecular docking and in vitro Aβ fibrillation were used to ensure the binding of drugs to Aβ. The in vitro cell viability study showed that the M + T SLNs showed enhanced neuroprotection against SHSY5Y cells than the pure drugs (M + T PD) in presence of Aβ (80.35µM ± 0.455 µM) at a 3:1 molar ratio. The Box-Behnken Design (BBD) was employed to optimize the SLNs and the optimized M + T SLNs were further characterized by %drug entrapment efficiency (99.24 ± 3.24 of MeHCl and 89.99 ± 0.95 of TMPS), particle size (159.9 ± 0.569 nm), PDI (0.149 ± 0.08), Zeta potential (-6.4 ± 0.948 mV), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and in vitro drug release. The TEM & AFM analysis showed irregularly spherical morphology. In vitro release of SLNs was noted up to 48 h; whereas the pure drugs released completely within 3 hrs. M + T SLNs revealed an improved pharmacokinetic profile and a 4-fold increase in drug concentration in the brain when compared to the pure drug. Behavioral tests showed enhanced spatial memory and histological studies confirmed reduced Aβ plaques in rat hippocampus. Furthermore, the levels of Aβ decreased in AlCl3-induced AD. Thus, all these noted results established that the M + T SLNs provide enhanced neuroprotective effects when compared to pure and individual drugs and can be a promising therapeutic strategy for the management of AD.

Effects of two Ayurvedic formulations, Dhanwantaram Kashaya and Saraswatarishta on life history parameters and toxic aggregates in Drosophila models of Huntington’s and Alzheimer's disease

Ethnopharmacological relevanceAyurveda, the traditional healthcare system native to India, employs dosage forms containing multiple herbs in treating various clinical conditions. Dhanwantaram Kashaya (DK) and Saraswatarishta (SA) are two such formulations containing multiple herbs in varied proportions. Kashaya is a liquid decoction while Arishta is fermented liquid with permissible quantity of self-generated alcohol in it. Both the formulations have been reported to have clinical efficacy in age-related memory impairment. Other mental disorders having clinical presentations similar to psychoses are the other indications for these tested formulations. Aim of the studyThe present study was performed to evaluate the efficacy of two Rasayana formulations i.e., DK and SA, used by clinicians in different neurodegenerative conditions. We tested these formulations in Alzheimer's (AD) and Huntington's disease (HD) models of Drosophila melanogaster. Materials and methodInitial experiments looking for life-history parameters in wild-type larvae were carried out in three sets with hundred larvae in each set. These parameters were also studied in diseased models in four sets with eighty larvae in each set. Aβ plaques and polyQ aggregates were looked at with the help of immunostaining technique and images were captured using confocal microscopy. ResultsThe results revealed that 0.25% concentration of both the formulations improve longevity in wild-type flies. Larval development and adult lifespan in Eye-GAL4>Aβ42 (AD) and GMR-GAL4>127Q (HD) larvae/flies reared on 0.25% & 0.50% DK and 0.25% & 1.00% SA improved substantially. Reduced Aβ plaques and polyQ aggregates indicate disease suppression. ConclusionDK and SA enhanced longevity in Drosophila melanogaster. Suppression of disease aggregates suggests their potential utility in treating AD and HD. Further clinical and pharmaceutical studies are required to confirm these results, however, this is a workable model to test multi-herbal formulations of Ayurveda in the forms they are clinically used.

Beneficial Effect of ACI-24 Vaccination on Aβ Plaque Pathology and Microglial Phenotypes in an Amyloidosis Mouse Model.

Amyloid-β (Aβ) deposition is an initiating factor in Alzheimer's disease (AD). Microglia are the brain immune cells that surround and phagocytose Aβ plaques, but their phagocytic capacity declines in AD. This is in agreement with studies that associate AD risk loci with genes regulating the phagocytic function of immune cells. Immunotherapies are currently pursued as strategies against AD and there are increased efforts to understand the role of the immune system in ameliorating AD pathology. Here, we evaluated the effect of the Aβ targeting ACI-24 vaccine in reducing AD pathology in an amyloidosis mouse model. ACI-24 vaccination elicited a robust and sustained antibody response in APPPS1 mice with an accompanying reduction of Aβ plaque load, Aβ plaque-associated ApoE and dystrophic neurites as compared to non-vaccinated controls. Furthermore, an increased number of NLRP3-positive plaque-associated microglia was observed following ACI-24 vaccination. In contrast to this local microglial activation at Aβ plaques, we observed a more ramified morphology of Aβ plaque-distant microglia compared to non-vaccinated controls. Accordingly, bulk transcriptomic analysis revealed a trend towards the reduced expression of several disease-associated microglia (DAM) signatures that is in line with the reduced Aβ plaque load triggered by ACI-24 vaccination. Our study demonstrates that administration of the Aβ targeting vaccine ACI-24 reduces AD pathology, suggesting its use as a safe and cost-effective AD therapeutic intervention.

Near-Infrared Aggregation-Induced Emission Luminogens for In Vivo Theranostics of Alzheimer's Disease.

Optimized theranostic strategies for Alzheimer's disease (AD) remain almost absent from bench to clinic. Current probes and drugs attempting to prevent β-amyloid (Aβ) fibrosis encounter failures due to the blood-brain barrier (BBB) penetration challenge and blind intervention time window. Herein, we design a near-infrared (NIR) aggregation-induced emission (AIE) probe, DNTPH, via balanced hydrophobicity-hydrophilicity strategy. DNTPH binds selectively to Aβ fibrils with a high signal-to-noise ratio. In vivo imaging revealed its excellent BBB permeability and long-term tracking ability with high-performance AD diagnosis. Remarkably, DNTPH exhibits a strong inhibitory effect on Aβ fibrosis and promotes fibril disassembly, thereby attenuating Aβ-induced neurotoxicity. DNTPH treatment significantly reduced Aβ plaques and rescued learning deficits in AD mice. Thus, DNTPH serves as the first AIE in vivo theranostic agent for real-time NIR imaging of Aβ plaques and AD therapy simultaneously.

Near‐Infrared Aggregation‐Induced Emission Luminogens for In Vivo Theranostics of Alzheimer's Disease

AbstractOptimized theranostic strategies for Alzheimer's disease (AD) remain almost absent from bench to clinic. Current probes and drugs attempting to prevent β‐amyloid (Aβ) fibrosis encounter failures due to the blood–brain barrier (BBB) penetration challenge and blind intervention time window. Herein, we design a near‐infrared (NIR) aggregation‐induced emission (AIE) probe, DNTPH, via balanced hydrophobicity‐hydrophilicity strategy. DNTPH binds selectively to Aβ fibrils with a high signal‐to‐noise ratio. In vivo imaging revealed its excellent BBB permeability and long‐term tracking ability with high‐performance AD diagnosis. Remarkably, DNTPH exhibits a strong inhibitory effect on Aβ fibrosis and promotes fibril disassembly, thereby attenuating Aβ‐induced neurotoxicity. DNTPH treatment significantly reduced Aβ plaques and rescued learning deficits in AD mice. Thus, DNTPH serves as the first AIE in vivo theranostic agent for real‐time NIR imaging of Aβ plaques and AD therapy simultaneously.

L‐Type calcium channel antagonist isradipine decreases area of plaque associated dystrophic neurites in 5XFAD mouse model

AbstractBackgroundEpidemiological studies suggest that L‐type calcium channel (LTCC) antagonists may reduce the incidence of neurodegenerative diseases including Alzheimer’s disease (AD). However, the neuroprotective mechanism of LTCC antagonists is unknown. Amyloid‐β (aβ) increases intracellular calcium signaling, which regulates lysosomal processing and microglial inflammatory responses, both of which are altered in AD. Neurons near aβ plaques develop dystrophic neurites, which are abnormal axonal swellings that accumulate lysosomes. Further, microglia accumulate around aβ plaques and secrete inflammatory cytokines. We hypothesized that antagonism of LTCCs with isradipine would reduce aβ plaque associated dystrophic neurites and inflammatory microglia in the 5XFAD mouse model of AD by restoring normal intracellular calcium regulation.MethodWe treated 6‐ and 9‐month‐old 5XFAD mice with isradipine (3 mg/kg/day) or vehicle via subcutaneous pellets for 30 days. Following three weeks of treatment we tested locomotion and cognitive behavior via open field, novel object recognition and Morris water maze. We measured gene expression of inflammatory mediators (IL1β, TNF, CD68) and LTCC subunits (Cav1.2, Cav1.3) using qPCR. Using immunohistochemistry (IHC), we examined aβ plaque number and area (D54D2 and ThioS), microglia area (Iba1), dystrophic neurites area and particle number (LAMP1) normalized to total brain area.ResultIHC revealed that isradipine treatment in 9‐month‐old 5XFADs decreased the total area of LAMP1 positive dystrophic neurites (p = 0.0310) compared to vehicle‐treated 5XFADs; this change was not observed in the 6‐month‐old group. Isradipine treatment in the 9‐month‐old 5XFADs also led to a decreasing trend (p = 0.0552) in plaque load compared to vehicle‐treated 5xFADs as measured by IHC. Isradipine treatment did not modulate plaque associated microglia as measured by IHC or inflammatory gene expression as measured by qPCR, regardless of age. There was no treatment effect on behavior or expression of LTCC subunits.ConclusionOur data show that isradipine reduces aβ plaque associated dystrophic neurite pathology in 9‐month‐old 5XFAD mice, potentially showing LTCC play a role in mediating this specific phenotype. Our future studies will focus on understanding why antagonizing LTCCs leads to a decrease in LAMP1 and whether this is due to changes in lysosomal development and processing or other possible mechanisms.

Altered Affect and Increased CLIP+ B cells in the Meningeal Lymphatics of 5xFAD mice are mitigated by antagonizing MHCII‐associated invariant chain (CLIP)

AbstractBackgroundDepression often occurs prior to Alzheimer’s disease (AD) and both depression and AD have been linked to immune mechanisms. A key role for activated B cells in AD pathogenesis was recently identified. The study found that B cell depletion reduced Aβ plaque accumulation, neuroinflammation, and behavioral deficits in three AD transgenic mouse models. Our work has shown that treatment with a peptide antagonist for Major histocompatibility complex class II (MHCII) invariant peptide (CLIP), a key component in the transition between innate and adaptive immunity, results in selective depletion of pro‐inflammatory, CLIP+ve B cells and neuroprotection. We hypothesized that selective depletion of CLIP+ve B cells in the 5xFAD model of AD would reduce depression‐associated behavioral deficits.Method11‐week‐old male WT and 5xFAD mice underwent social interaction and burrowing pre‐testing. 12‐week‐old mice were treated once with a competitive antagonist peptide (CAP) or vehicle, followed by social interaction and burrowing testing once a month for 5 months. 6 months post‐treatment, meningeal lymphatics were collected, stained, and analyzed flow cytometrically for markers of B cells (CD19), T cells (CD3), and CLIP.ResultAffective alterations were observed in 5xFAD mice as early as 11 weeks of age and persisted up to 9 months of age. CAP treatment in 5xFAD mice protected against an age‐associated decline in social interaction. At 9 months of age 5xFAD mice were found to have significantly more B cells and CLIP+ve B cells in the meningeal lymphatics when compared to age‐matched WT, and CLIP+ve B cells were significantly decreased by a single CAP injection at 3 months of age.ConclusionA key function of B cells is their role as antigen presenting cells (APCs). CLIP occupies the MHCII antigen binding groove until it is displaced by antigen to be presented to CD4+ T cells, marking the transition between an innate and an adaptive immune response. Our findings suggest that 5xFAD mice exhibit depression‐associated behavior by 11 weeks of age, that CLIP+ve cells are elevated in 5xFAD mice, and that antagonizing CLIP depletes these B cells and functionally protects mice genetically predisposed to AD.

BIN1 K358R variant in 5xFAD mice ameliorates AB pathology and microgliosis

AbstractBackgroundGenome‐Wide Association Studies (GWAS) identified bridging integrator 1 (BIN1) as the most important susceptibility loci for late‐onset Alzheimer's disease (LOAD), second to apolipoprotein E (APOE). BIN1 is an important regulator of endocytosis and membrane dynamics. Neuronal BIN1 localizes to pre‐synaptic termini where it functions in excitatory synaptic transmission via regulation of neurotransmitter vesicle dynamics. In humans, the gene produces multiple isoforms with 7 brain specific isoforms. A missense variant in Bin1 (K358R) has been linked to increased risk of development of LOAD. Here, we introduced this variant in mice and evaluated its effects on plaque genesis and subsequent damage.MethodTo create the Bin1K358R allele, CRISPR/Cas9 endonuclease‐mediated genome editing of Bin1 was used to introduce a K426R mutation. This mutant allele models a SNP (rs138047593) found in human BIN1 that encodes a missense mutation associated with increased risk of sporadic Alzheimer's disease. The K358R variant in human BIN1 (K542R in the BIN1‐202 isoform) is located within the C‐terminal SH3 domain. Generated BIN1 K358R mice were crossed with 5xFAD mouse models, creating four groups (wild type (WT), BIN1K358R homozygous (HO), 5xFAD, and 5xFAD/BIN1 K358R HO), then aged to 4 months for analysis of AD‐related pathology. Coronal brain sections were immunolabeled to visualize dense‐core plaques (Thioflavin‐S), microglia (IBA1), reactive astrocytes (GFAP), axonal and neuritic damage (neurofilament light chain (NfL) and LAMP1, respectively). Confocal images of hippocampal and cortical regions were analyzed using Imaris software. In addition, Aβ and NfL levels were quantified in the brain tissue and plasma NfL measured using Meso Scale Discovery technology.ResultBIN1 K358R introduced in the 5xFAD background significantly reduces plaque densities and associated microgliosis in the hippocampal region, which matches insoluble Aβ42 levels. In contrast, GFAP levels are significantly increased in 5xFAD/BIN1 K358R mice compared to 5xFAD mice. Despite reduced plaque densities, dystrophic neurite area as measured by LAMP1 staining, as well as plasma NfL, are equivalent between 5xFAD/BIN1 K358R and 5xFAD mice, suggesting increased damage per plaque.ConclusionBIN1 K358R reduces Aβ plaque deposition, but exacerbates the damage caused by those plaques, as determined by the surrounding halo of dystrophic neurites, and plasma NfL.

Level of Amyloid-β (Aβ) Binding Leading to Differential Effects on Resting State Functional Connectivity in Major Brain Networks.

Introduction: Amyloid-β protein (Aβ) is one of the biomarkers for Alzheimer’s disease (AD). The recent application of interhemispheric functional connectivity (IFC) in resting-state fMRI has been used as a non-invasive diagnostic tool for early dementia. In this study, we focused on the level of Aβ accumulated and its effects on the major functional networks, including default mode network (DMN), central executive network (CEN), salience network (SN), self-referential network (SRN) and sensory motor network (SMN). Methods: 58 participants (27 Hi Aβ (HiAmy) and 31 low Aβ (LowAmy)) and 25 healthy controls (HC) were recruited. [18F]flutemetamol PET/CT was performed for diseased groups, and MRI scanning was done for all participants. Voxel-by-voxel correlation analysis was done for both groups in all networks. Results: In HiAmy, IFC was reduced in all networks except SN. A negative correlation in DMN, CEN, SRN and SMN suggests high Aβ related to IFC reduction; However, a positive correlation in SN suggests high Aβ related to an increase in IFC. In LowAmy, IFC increased in CEN, SMN, SN and SRN. Positive correlation in all major brain networks. Conclusion: The level of Aβ accumulated demonstrated differential effects on IFC in various brain networks. As the treatment to reduce Aβ plaque deposition is available in the market, it may be an option for the HiAmy group to improve their IFC in major brain networks.

Miconazole Promotes Cooperative Ability of a Mouse Model of Alzheimer Disease.

Cooperative defect is 1 of the earliest manifestations of disease patients with Alzheimer disease (AD) exhibit, but the underlying mechanism remains unclear. We evaluated the cooperative function of APP/PS1 transgenic AD model mice at ages 2, 5, and 8 months by using a cooperative drinking task. We examined neuropathologic changes in the medial prefrontal cortex (mPFC). Another experiment was designed to observe whether miconazole, which has a repairing effect on myelin sheath, could promote the cooperative ability of APP/PS1 mice in the early AD-like stage. We also investigated the protective effects of miconazole on cultured mouse cortical oligodendrocytes exposed to human amyloid β peptide (Aβ1-42). We observed an age-dependent impairment of cooperative water drinking behavior in APP/PS1 mice. The AD mice with cooperative dysfunction showed decreases in myelin sheath thickness, oligodendrocyte nuclear heterochromatin percentage, and myelin basic protein expression levels in the mPFC. The cooperative ability was significantly improved in APP/PS1 mice treated with miconazole. Miconazole treatment increased oligodendrocyte maturation and myelin sheath thickness without reducing Aβ plaque deposition, reactive gliosis, and inflammatory factor levels in the mPFC. Miconazole also protected cultured oligodendrocytes from the toxicity of Aβ1-42. These results demonstrate that mPFC hypomyelination is involved in the cooperative deficits of APP/PS1 mice. Improving myelination through miconazole therapy may offer a potential therapeutic approach for early intervention in AD.

Effect of cx-DHED on Abnormal Glucose Transporter Expression Induced by AD Pathologies in the 5xFAD Mouse Model.

Alzheimer’s disease (AD) is a form of dementia associated with abnormal glucose metabolism resulting from amyloid-beta (Aβ) plaques and intracellular neurofibrillary tau protein tangles. In a previous study, we confirmed that carboxy-dehydroevodiamine∙HCl (cx-DHED), a derivative of DHED, was effective at improving cognitive impairment and reducing phosphorylated tau levels and synaptic loss in an AD mouse model. However, the specific mechanism of action of cx-DHED is unclear. In this study, we investigated how the cx-DHED attenuates AD pathologies in the 5xFAD mouse model, focusing particularly on abnormal glucose metabolism. We analyzed behavioral changes and AD pathologies in mice after intraperitoneal injection of cx-DHED for 2 months. As expected, cx-DHED reversed memory impairment and reduced Aβ plaques and astrocyte overexpression in the brains of 5xFAD mice. Interestingly, cx-DHED reversed the abnormal expression of glucose transporters in the brains of 5xFAD mice. In addition, otherwise low O-GlcNac levels increased, and the overactivity of phosphorylated GSK-3β decreased in the brains of cx-DHED-treated 5xFAD mice. Finally, the reduction in synaptic proteins was found to also improve by treatment with cx-DHED. Therefore, we specifically demonstrated the protective effects of cx-DHED against AD pathologies and suggest that cx-DHED may be a potential therapeutic drug for AD.

Intravenous treatment with a molecular chaperone designed against β-amyloid toxicity improves Alzheimer’s disease pathology in mouse models

Attempts to treat Alzheimer's disease with immunotherapy against the β-amyloid (Aβ) peptide or with enzyme inhibitors to reduce Aβ production have not yet resulted in effective treatment, suggesting that alternative strategies may be useful. Here we explore the possibility of targeting the toxicity associated with Aβ aggregation by using the recombinant human (rh) Bri2 BRICHOS chaperone domain, mutated to act selectively against Aβ42 oligomer generation and neurotoxicity invitro. We find that treatment of Aβ precursor protein (App) knockin mice with repeated intravenous injections of rh Bri2 BRICHOS R221E, from an age close to the start of development of Alzheimer's disease-like pathology, improves recognition and working memory, as assessed using novel object recognition and Y maze tests, and reduces Aβ plaque deposition and activation of astrocytes and microglia. When treatment was started about 4months after Alzheimer's disease-like pathology was already established, memory improvement was not detected, but Aβ plaque deposition and gliosis were reduced, and substantially reduced astrocyte accumulation in the vicinity of Aβ plaques was observed. The degrees of treatment effects observed in the App knockin mouse models apparently correlate with the amounts of Bri2 BRICHOS detected in brain sections after the end of the treatment period.