Therapeutic Effects of Human Amniotic Epithelial Stem Cells in a Transgenic Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is characterized clinically by cognitive decline and pathologically by the development of amyloid plaques. AD is the most common cause of dementia among older people. However, there is currently no cure for AD. In this study, we aimed to elucidate the therapeutic effects of human amniotic epithelial stem cells (hAESCs) in a transgenic mouse model of AD. Tg2576 transgenic (Tg) mice underwent behavioral tests, namely the Morris water maze and Y-maze tests, to assess their cognitive function. In the Morris water maze test, hAESC-treated Tg mice exhibited significantly shorter escape latencies than vehicle-treated Tg mice. In the Y-maze test, hAESC-treated Tg mice exhibited significantly higher rate of spontaneous alteration than vehicle-treated Tg mice, while the total number of arm entries did not differ between the groups. Furthermore, Congo red staining revealed that hAESCs injection reduced the number of amyloid plaques present in the brains of Tg mice. Finally, beta-secretase (BACE) activity was significantly decreased in Tg mice at 60 min after hAESCs injection. In this study, we found that intracerebral injection of hAESCs alleviated cognitive impairment in a Tg2576 mouse model of AD. Our results indicate that hAESCs injection reduced amyloid plaques caused by reduced BACE activity. These results indicate that hAESCs may be a useful therapeutic agent for the treatment of AD-related memory impairment.

Distinct amyloid precursor protein processing machineries of the olfactory system.

Processing of amyloid precursor protein (APP) occurs through sequential cleavages first by ß-secretase and then by the γ-secretase complex. However, abnormal processing of APP leads to excessive production of ß-amyloid (Aß) in the central nervous system (CNS), an event which is regarded as a primary cause of Alzheimer's disease (AD). In particular, gene mutations of the γ-secretase complex-which contains presenilin 1 or 2 as the catalytic core-could trigger marked Aß accumulation. Olfactory dysfunction usually occurs before the onset of typical AD-related symptoms (eg, memory loss or muscle retardation), suggesting that the olfactory system may be one of the most vulnerable regions to AD. To date however, little is known about why the olfactory system is affected so early by AD prior to other regions. Thus, we examined the distribution of secretases and levels of APP processing in the olfactory system under either healthy or pathological conditions. Here, we show that the olfactory system has distinct APP processing machineries. In particular, we identified higher expressions levels and activity of γ-secretase in the olfactory epithelium (OE) than other regions of the brain. Moreover, APP c-terminal fragments (CTF) are markedly detected. During AD progression, we note increased expression of presenilin2 of γ-secretases in the OE, not in the OB, and show that neurotoxic Aß*56 accumulates more quickly in the OE. Taken together, these results suggest that the olfactory system has distinct APP processing machineries under healthy and pathological conditions. This finding may provide a crucial understanding of the unique APP-processing mechanisms in the olfactory system, and further highlights the correlation between olfactory deficits and AD symptoms.

Dehydroevodiamine·HCl enhances cognitive function in memory-impaired rat models.

Progressive memory impairment such as that associated with depression, stroke, and Alzheimer's disease (AD) can interfere with daily life. In particular, AD, which is a progressive neurodegenerative disorder, prominently features a memory and learning impairment that is related to changes in acetylcholine and abnormal ß-amyloid (Aß) deposition in the brain. In the present study, we investigated the effects of dehydroevodiamine·HCl (DHED) on cognitive improvement and the related mechanism in memory-impaired rat models, namely, a scopolamine-induced amnesia model and a Aß1-42-infused model. The cognitive effects of DHED were measured using a water maze test and a passive avoidance test in the memory-impaired rat models. The results demonstrate that DHED (10 mg/kg, p.o.) and Donepezil (1 mg/kg, p.o.) ameliorated the spatial memory impairment in the scopolamine-induced amnestic rats. Moreover, DHED significantly improved learning and memory in the Aß1-42-infused rat model. Furthermore, the mechanism of these behavioral effects of DHED was investigated using a cell viability assay, reactive oxygen species (ROS) measurement, and intracellular calcium measurement in primary cortical neurons. DHED reduced neurotoxicity and the production of Aß-induced ROS in primary cortical neurons. In addition, similar to the effect of MK801, DHED decreased intracellular calcium levels in primary cortical neurons. Our results suggest that DHED has strong protective effects against cognitive impairments through its antioxidant activity and inhibition of neurotoxicity and intracellular calcium. Thus, DHED may be an important therapeutic agent for memory-impaired symptoms.

Involvement of 14-3-3 in tubulin instability and impaired axon development is mediated by Tau.

14-3-3 proteins act as adapters that exert their function by interacting with their various protein partners. 14-3-3 proteins have been implicated in a variety of human diseases including neurodegenerative diseases. 14-3-3 proteins have recently been reported to be abundant in the neurofibrillary tangles (NFTs) observed inside the neurons of brains affected by Alzheimer's disease (AD). These NFTs are mainly constituted of phosphorylated Tau protein, a microtubule-associated protein known to bind 14-3-3. Despite this indication of 14-3-3 protein involvement in the AD pathogenesis, the role of 14-3-3 in the Tauopathy remains to be clarified. In the present study, we shed light on the role of 14-3-3 proteins in the molecular pathways leading to Tauopathies. Overexpression of the 14-3-3σ isoform resulted in a disruption of the tubulin cytoskeleton and prevented neuritic outgrowth in neurons. NMR studies validated the phosphorylated residues pSer214 and pSer324 in Tau as the 2 primary sites for 14-3-3 binding, with the crystal structure of 14-3-3σ in complex with Tau-pSer214 and Tau-pSer324 revealing the molecular details of the interaction. These data suggest a rationale for a possible pharmacologic intervention of the Tau/14-3-3 interaction.

Cyclin-dependent kinase 5 (Cdk5) regulates the function of CLOCK protein by direct phosphorylation.

Circadian rhythm is a biological rhythm governing physiology and behavior with a period of ∼24 h. At the molecular level, circadian output is controlled by a molecular clock composed of positive and negative feedback loops in transcriptional and post-translational processes. CLOCK is a transcription factor known as a central component of the molecular clock feedback loops generating circadian oscillation. Although CLOCK is known to undergo multiple post-translational modifications, the knowledge of their entities remains limited. Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine-threonine kinase that is involved in various neuronal processes. Here, we report that Cdk5 is a novel regulator of CLOCK protein. Cdk5 phosphorylates CLOCK at the Thr-451 and Thr-461 residues in association with transcriptional activation of CLOCK. The Cdk5-dependent regulation of CLOCK function is mediated by alterations of its stability and subcellular distribution. These results suggest that Cdk5 is a novel regulatory component of the core molecular clock machinery.

Facile "stop codon" method reveals elevated neuronal toxicity by discrete S87p-α-synuclein oligomers.

Herein, a new method for preparing phosphorylated proteins at specific sites has been applied to α-synuclein (α-Syn). Three different α-Syn species phosphorylated at Serine 87 (S87p-α-Syn), Serine 129 (S129p-α-Syn) and Serine 87/129 (S87p,129p-α-Syn) were prepared through the 'stop codon' method and verified by LC/MS/MS and immunoblotting. Each type of phosphorylated α-Syn was tested for oligomerization trends and cellular toxicity with dopamine (DA), Cu(2+) ions and pyridoxal 5'-phosphate. Aggregation trends induced by DA or DA/Cu(2+) were similar between phosphorylated and non-phosphorylated α-Syn in SDS-PAGE. However, except for the monomer, phosphorylated oligomers showed higher toxicity than the non-phosphorylated α-Syn (Np-α-Syn) oligomers via WST-1 assays when tested on SH-SY5Y human neuroblastoma cells. In particular, S87p-α-Syn and S87p,129p-α-Syn oligomers induced by DA/Cu(2+), showed higher toxicity than did S129p-α-Syn. When α-Syn was treated with pyridoxal 5'-phosphate in the presence of DA or Cu(2+) to determine aggregation effects, high inhibition effects were shown in both non-phosphorylated and phosphorylated versions. α-Syn co-incubated with DA or DA/Cu(2+) showed less cellular toxicity upon pyridoxal 5'-phosphate treatment, especially in the case of DA-induced Np-α-syn. This study supports that phosphorylated oligomers of α-Syn at residue 87 can contribute to neuronal toxicity and the pyridoxal 5'-phosphate can be used as an inhibitor for α-Syn aggregation.

Dopamine and Cu+/2+ can induce oligomerization of α-synuclein in the absence of oxygen: Two types of oligomerization mechanisms for α-synuclein and related cell toxicity studies.

α-Synuclein oligomers can induce neurotoxicity and are implicated in Parkinson's disease etiology and disease progression. Many studies have reported α-synuclein oligomerization by dopamine (DA) and transition metal ions, but few studies provide insight into joint influences of DA and Cu2+ . In this study, DA and Cu2+ were coadministered aerobically to measure α-synuclein oligomerization under these conditions. In the presence of oxygen, DA induced α-synuclein oligomerization in a dose-dependent manner. Cu+/2+ did not effect oligomerization in such a manner in the presence of DA. By electrophoresis, Cu2+ was found easily to induce oligomerization with DA. This implies that oligomerization invoked by DA is reversible in the presence of Cu2+, which appears to be mediated by noncovalent bond interactions. In the absence of oxygen, DA induced less oligomerization of α-synuclein, whereas DA/Cu2+ induced aerobic-level amounts of oligomers, suggesting that DA/Cu2+ induces oligomerization independent of oxygen concentration. Radical species were detected through electron paramagnetic resonance (EPR) spectroscopic analysis arising from coincubation of DA/Cu2+ with α-synuclein. Redox reactions induced by DA/Cu2+ were observed in multimer regions of α-synuclein oligomers through NBT assay. Cellular toxicity results confirm that, for normal and hypoxic conditions, copper or DA/Cu2+ can induce cell death, which may arise from copper redox chemistry. From these results, we propose that DA and DA/Cu2+ induce different mechanisms of α-synuclein oligomerization, cross-linking with noncovalent (or reversible covalent) bonding vs. likely radical-mediated covalent modification.

Therapeutic potential of human adipose-derived stem cells in neurological disorders.

Stem cell therapy has been noted as a novel strategy to various diseases including neurological disorders such as Alzheimer's disease, Parkinson's disease, stroke, amyotrophic lateral sclerosis, and Huntington's disease that have no effective treatment available to date. The adipose-derived stem cells (ASCs), mesenchymal stem cells (MSCs) isolated from adipose tissue, are well known for their pluripotency with the ability to differentiate into various types of cells and immuno-modulatory property. These biological features make ASCs a promising source for regenerative cell therapy in neurological disorders. Here we discuss the recent progress of regenerative therapies in various neurological disorders utilizing ASCs.

The therapeutic effects of human adipose-derived stem cells in Alzheimer's disease mouse models.

Alzheimer's disease (AD) is an irreversible neurodegenerative disease, still lacking proper clinical treatment. Therefore, many researchers have focused on the possibility of therapeutic use of stem cells for AD. Adipose-derived stem cells (ASCs), mesenchymal stem cells (MSCs) isolated from adipose tissue, are well known for their pluripotency and their ability to differentiate into multiple tissue types and have immune modulatory properties similar to those of MSCs from other origins. Because of their biological properties, ASCs can be considered for cell therapy and neuroregeneration. Our recent results clearly showed the therapeutic potential of these cells after transplantation into Tg2576 mice (an AD mouse model). Intravenously or intracerebrally transplanted human ASCs (hASCs) greatly improved the memory impairment and the neuropathology, suggesting that hASCs have a high therapeutic potential for AD.

Dehydroevodiamine·HCl Improves Stress-Induced Memory Impairments and Depression Like Behavior in Rats.

Dehydroevodiamine·HCl (DHED) has been reported to prevent memory impairment and neuronal cell loss in a rat model with cognitive disturbance. We investigated the effect of DHED on memory impairment and behavioral abnormality caused by stress. We demonstrated that DHED can improve stress-induced memory impairments and depression-like behaviors by using open-field test, Y-maze test and forced swimming test. DHED treatment significantly recovered the decreases in the levels of neural cell adhesion molecule (NCAM) proteins caused by stress and the decreases in cell viability. Our results suggested that DHED is a potential drug candidate for neuronal death, memory impairment and depression induced by stress.

An activity-regulated microRNA, miR-188, controls dendritic plasticity and synaptic transmission by downregulating neuropilin-2.

MicroRNAs (miRNAs) have recently come to be viewed as critical players that modulate a number of cellular features in various biological systems including the mature CNS by exerting regulatory control over the stability and translation of mRNAs. Despite considerable evidence for the regulatory functions of miRNAs, the identities of the miRNA species that are involved in the regulation of synaptic transmission and plasticity and the mechanisms by which these miRNAs exert functional roles remain largely unknown. In the present study, the expression of microRNA-188 (miR-188) was found to be upregulated by the induction of long-term potentiation (LTP). The protein level of neuropilin-2 (Nrp-2), one of the possible molecular targets for miR-188, was decreased during LTP induction. We also confirmed that the luciferase activity of the 3'-UTR of Nrp-2 was diminished by treatment with a miR-188 oligonucleotide but not with a scrambled miRNA oligonucleotide. Nrp-2 serves as a receptor for semaphorin 3F, which is a negative regulator of spine development and synaptic structure. In addition, miR-188 specifically rescued the reduction in dendritic spine density induced by Nrp-2 expression in hippocampal neurons from rat primary culture. Furthermore, miR-188 counteracted the decrease in the miniature EPSC frequency induced by Nrp-2 expression in hippocampal neurons from rat primary culture. These findings suggest that miR-188 serves to fine-tune synaptic plasticity by regulating Nrp-2 expression.

Amyloid-ß peptide-induced extracellular S100A9 depletion is associated with decrease of antimicrobial peptide activity in human THP-1 monocytes.

BACKGROUND: S100A9 protein (myeloid-related protein MRP14, also referred to as calgranulin B) is a reliable marker of inflammation, an important proinflammatory factor of innate immunity and acts as an additional antimicrobial peptide in the innate immune system. Evidence indicates that S100A9 contributes to Alzheimer's disease (AD) pathology, although the precise mechanisms are not clear. METHODS: We were interested to study the mechanisms of S100A9 release upon Aß1-42 stimulation, the potential roles of extracellular S100A9 depletion in Aß-induced cytotoxicity, and the interaction with innate immune response in THP-1 monocytic cells that have been challenged with mostly Aß1-42 monomers instead of oligomers. We used protein preparation, Ca(2+) influx fluorescence imaging, MTT assay, siRNA knockdown, colony forming units (CFUs) assay and western blotting techniques to perform our study. RESULTS: Aß1-42 monomers elicited a marked decrease of S100A9 release into the cell culture supernatant in a dose-dependent manner in human THP-1 monocytes. This reduction of S100A9 release was accompanied by an increase of intracellular Ca(2+) level. Aß1-42-mediated decrease of S100A9 release was not associated with Aß1-42-induced cytotoxicity as measured by MTT reduction assay. This observation was confirmed with the recombinant S100A9, which had little effect on Aß1-42-induced cytotoxicity. Moreover, depletion of S100A9 with siRNA did not significantly evoke the cell toxicity. On the other hand, Aß1-42-induced extracellular S100A9 depletion resulted in decreased antimicrobial activity of the culture supernatant after Aß1-42 stimulation. Immunodepletion of S100A9 with anti-S100A9 also decreased the antimicrobial peptide activity of the vehicle treated culture supernatant. Consistently, the recombinant S100A9 clearly elicited the antimicrobial peptide activity in vitro, confirming the observed antimicrobial activity of S100A9 in the culture supernatant. CONCLUSION: Collectively, our findings suggest that the mostly monomeric form of Aß1-42 negatively regulates the innate immune system by down-regulating the secretion of S100A9, which is likely a main mediator of antimicrobial activity in the conditioned media of human THP-1 monocytes.

Extremely selective "turn-on" fluorescence detection of hypochlorite confirmed by proof-of-principle neurological studies via esterase action in living cells.

Highly specific and sensitive fluorescence detection of hypochlorite in nonbiotic pure water (rapid "turn-on", ~400 fold, λ(em) ~ 560 nm) as well as in living neuronal cell cultures (neutral pH) involves oxidation of a 2-sulfide-2-benzoic acid pendent group in a new meso-thienyl-BODIPY donor-acceptor probe.

Phosphorylation of α-synuclein is crucial in compensating for proteasomal dysfunction.

α-Synuclein can be degraded by both the ubiquitin-proteasomal system and the chaperone-lysosomal system. However, the switching mechanism between the two pathways is not clearly understood. In our study, we investigated the mutual association between the binding of α-synuclein to heat shock cognate 70 and the lysosomal translocation of α-synuclein. Tyrosine phosphorylation of Y136 on α-synuclein increased when it bound to heat shock protein 70. We also found that tyrosine phosphorylation of α-synuclein can be regulated by focal adhesion kinase pp125 and protein tyrosine phosphatase 1B. Furthermore, protein tyrosine phosphatase 1B inhibitor protected dopaminergic neurons against cell death and rescued rotarod performance in a Parkinson's disease animal model. This study provides evidence that the regulation of Y136 phosphorylation of α-synuclein can improve behavioral performance and protect against neuronal death by promoting the turnover of lysosomal degradation of α-synuclein. As a result, protein tyrosine phosphatase 1B inhibitor may be used as a potential therapeutic agent against Parkinson's disease.

15-deoxy-Δ¹²,¹4 -prostaglandin J2 inhibits human immunodeficiency virus-1 tat-induced monocyte chemoattractant protein-1/CCL2 production by blocking the extracellular signal-regulated kinase-1/2 signaling pathway independently of peroxisome proliferator-activated receptor-γ and heme oxygenase-1 in rat hippocampal slices.

Human immunodeficiency virus (HIV)-induced inflammation, and its consequences within the central nervous system (CNS), must be countered by multiple pharmacologic agents, and 15-deoxy-Δ(12,14) -prostaglandin J(2) (15d-PGJ2) may hold promise in the treatment of pathologies associated with this inflammatory response. 15d-PGJ2 can repress the inflammatory response by means of peroxisome proliferator-activated receptor-γ (PPARγ)-dependent and -independent mechanisms. However, its precise role and antiinflammatory mechanism in the hippocampus remain poorly understood. In the present study, rat hippocampal slices were stimulated with full-length HIV-1 Tat protein to investigate the role of 15d-PGJ2 8in the hippocampal inflammatory response. Pretreatment of slices with 15d-PGJ2 markedly reduced Tat-induced monocyte chemoattractant protein-1 (MCP-1/CCL2) production. Interestingly, the PPARγ antagonist GW9662 did not inhibit action of 15d-PGJ2, confirming the latter's PPARγ-independent mechanism of mediating antiinflammatory effects. Despite 15d-PGJ2's increasing the expression of heme oxygenase-1 (HO-1), its action was not abrogated by the HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX), nor was it recapitulated by HO-1 inducers such as cobalt protoporphyrin (CoPP). Moreover, short interfering RNA (siRNA)-directed knockdown of HO-1 did not abolish the antiinflammatory action of 15d-PGJ2 against Tat-induced MCP-1 production in human microglia-like THP-1 cells. Conversely, 15d-PGJ2 suppressed Tat-induced ERK1/2 activation, decreasing MCP-1 production upon Tat stimulation. The NADPH oxidase inhibitors DPI and apocynin also abrogated Tat-stimulated ERK1/2 activation, reducing MCP-1 production. Collectively, these data demonstrate that the antiinflammatory effects of 15d-PGJ2 on the hippocampus are exerted through inhibition of Tat-mediated ERK1/2 activation, coupled with that of a redox-sensitive pathway, independent of PPARγ and HO-1.

The role of S100a9 in the pathogenesis of Alzheimer's disease: the therapeutic effects of S100a9 knockdown or knockout.

Neuroinflammation is one of the important pathogenic features of Alzheimer's disease (AD). Recently, S100a9 was found to be increased within neuritic plaques and reactive glia and was proposed to participate in the inflammation associated with the pathogenesis of AD. Our study showed that S100a9 expression was increased in the brains of AD mice and AD patients. In Tg2576 mice, knockdown by short hairpin RNA or knockout of the S100a9 gene significantly reduced the neuropathology, greatly improved the learning and memory impairment and reduced the amount of Aß and APP-CTs by increasing neprilysin and decreasing BACE activity. These results clearly show that the upregulation of the S100a9 gene plays an important role in the neuropathology and memory impairment in AD, suggesting that the knockdown and knockout of this gene have a great therapeutic potential for AD.

Environmental enrichment compensates for the effects of stress on disease progression in Tg2576 mice, an Alzheimer's disease model.

Various environmental factors are known to influence the onset and progression of Alzheimer's disease (AD). Environmental enrichment was reported to improve cognitive performance in various Alzheimer's transgenic mice via an amyloid-related or unrelated mechanism. However, stress has been found to accelerate amyloid deposition and cognitive deficits in many AD models. The aim of this study was to determine whether environmental enrichment compensates for the effects of stress on disease progression in the Tg2576 mice, an established AD model. We housed Tg2576 mice under environmental enrichment, enrichment plus stress, stress, or control conditions at 3 months of age. In this study, we first report that environmental enrichment counteracts the effects of stress in terms of cognitive deficits, tau phosphorylation, neurogenesis, and neuronal proliferation during AD-like disease progression. These results strongly implicate the importance of environmental factors as a major modulator for the disease progression of AD.

Nanotechnology, nanotoxicology, and neuroscience.

Nanotechnology, which deals with features as small as a 1 billionth of a meter, began to enter into mainstream physical sciences and engineering some 20 years ago. Recent applications of nanoscience include the use of nanoscale materials in electronics, catalysis, and biomedical research. Among these applications, strong interest has been shown to biological processes such as blood coagulation control and multimodal bioimaging, which has brought about a new and exciting research field called nanobiotechnology. Biotechnology, which itself also dates back approximately 30 years, involves the manipulation of macroscopic biological systems such as cells and mice in order to understand why and how molecular level mechanisms affect specific biological functions, e.g., the role of APP (amyloid precursor protein) in Alzheimer's disease (AD). This review aims (1) to introduce key concepts and materials from nanotechnology to a non-physical sciences community; (2) to introduce several state-of-the-art examples of current nanotechnology that were either constructed for use in biological systems or that can, in time, be utilized for biomedical research; (3) to provide recent excerpts in nanotoxicology and multifunctional nanoparticle systems (MFNPSs); and (4) to propose areas in neuroscience that may benefit from research at the interface of neurobiologically important systems and nanostructured materials.

Interleukin-17 induced by cumulative mild stress promoted depression-like behaviors in young adult mice.

The number of young adult patients with major depression, one of the most common mental disorders, is gradually increasing in modern society. Stressful experiences in early life are considered one of the risk factors for chronic depressive symptoms, along with an abnormal inflammatory response in later life. Although increased inflammatory activity has been identified in patients with depression, the cause of long-lasting depressive states is still unclear. To identify the effects of cumulative mild stress in brain development periods, we generated a young adult depression mouse model exposed to cumulative mild stress (CPMS; cumulative mild prenatal stress, mild maternal separation, and mild social defeat) to mimic early life adversities. CPMS mice exhibited more long-lasting anxiety and depression-like behaviors than groups exposed to single or double combinations of mild stress in young adult age. Using the molecular works, we found that inflammatory cytokines, especially interleukin (IL)-17, upregulated microglial activation in the hippocampus, amygdala, and prefrontal cortex of CPMS mice. In the brains of CPMS mice, we also identified changes in the T helper (Th)-17 cell population as well as differentiation. Finally, anti-IL-17 treatment rescued anxiety and depression-like behavior in CPMS mice. In conclusion, we found that cumulative mild stress promoted long-lasting depressive symptoms in CPMS mice through the upregulation of IL-17. We suggest that the CPMS model may be useful to study young adult depression and expect that IL-17 may be an important therapeutic target for depression in young adults.

Long-Term Treatment of Cuban Policosanol Attenuates Abnormal Oxidative Stress and Inflammatory Response via Amyloid Plaques Reduction in 5xFAD Mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in cognitive decline or dementia, the number of patients with AD is continuously increasing. Although a lot of great progress has been made in research and development of AD therapeutics, there is no fundamental cure for this disease yet. This study demonstrated the memory-improving effects of Cuban policosanol (PCO) in 5xFAD mice, which is an animal model of AD. Following 4-months of treatment with PCO in 5xFAD mice, we found that the number of amyloid plaques decreased in the brain compared to the vehicle-treated 5xFAD mice. Long-term PCO treatment in 5xFAD mice resulted in the reduction of gliosis and abnormal inflammatory cytokines level (interleukin [IL]-1ß, IL-6, and tumor necrosis factor [TNF]-α) in the cortex and hippocampus. Levels of lipid peroxide (4-hydroxynonenal [4-HNE]) and superoxide dismutase (SOD1 and SOD2) levels were also recoverd in the brains of PCO-treated 5xFAD mice. Notably, PCO administration reduced memory deficits in the passive avoidance test, as well as synaptic loss (PSD-95, synaptophysin) in 5xFAD mice. Collectively, we identified the potential effects of PCO as a useful supplement to delay or prevent AD progression by inhibiting the formation of Aß plaques in the brain.