Therapeutic effect of a novel curcumin derivative GT863 on a mouse model of amyotrophic lateral sclerosis.

The present study investigated the therapeutic effects of the curcumin derivative 3-[(1E)-2-(1H-indol-6-yl)ethenyl]-5-[(1E)-2-[2-methoxy-4-(2-pyridylmethoxy)phenyl]ethenyl]-1H-pyrazole (GT863) in amyotrophic lateral sclerosis (ALS). The inhibitory effect of GT863 on superoxide dismutase 1 (SOD1) aggregation was evaluated in cell-free assays. GT863 interfered with the conformational changes of the SOD1 protein and later, oligomeric aggregation. Furthermore, its antioxidant, anti-inflammatory, and neuroprotective effects were evaluated in cell-free and cultured cell assays. GT863 inhibited H2O2- and glutamate-induced cytotoxicity and activated an antioxidant responsive element pathway. Additionally, in vivo effects of GT863 in the ALS mice model were evaluated by its oral administration to H46R mutant SOD1 transgenic mice. Rotarod test showed that GT863 administration significantly slowed the progression of motor dysfunction in the mice. In addition, GT863 substantially reduced highly-aggregated SOD1, further preserving large neurons in the spinal cord of GT863-treated mice. Collectively, these results indicated that GT863 could be a viable therapeutic agent with multiple vital actions for the treatment of ALS.

Aromatherapy improves cognitive dysfunction in senescence-accelerated mouse prone 8 by reducing the level of amyloid beta and tau phosphorylation.

Alzheimer's disease (AD) is a progressive neurodegenerative disease and is known to be the most common cause of dementia. We previously described the benefits of aromatherapy on the cognitive function of patients with AD utilizing various aromatic essential oils; however, its mechanism of action remains poorly understood. Consequently, in the present study, this mechanism was thoroughly evaluated employing a dementia mice model, specifically the senescence-accelerated mouse prone 8. The mice were exposed to a mixture of lemon and rosemary oil at nighttime as well as to a mixture of lavender and orange oil in the daytime for 2 months. The cognitive function of the mice was assessed before and after treatment with the aromatic essential oils using the Y-maze test. Moreover, the brain levels of amyloid beta (Aß), abnormally phosphorylated tau, and brain-derived neurotrophic factor (BDNF) were measured following treatment. The benefits of aromatherapy on the cognitive function in mice were confirmed. It was also established that the brain levels of Aß and abnormally phosphorylated tau were considerably lower in the aromatherapy group, while the levels of BDNF were marginally higher. These results suggest that aromatherapy employing these aromatic essential oils is beneficial for the prevention and treatment of AD.

Development of a brain-permeable peptide nanofiber that prevents aggregation of Alzheimer pathogenic proteins.

Alzheimer's disease (AD) is proposed to be induced by abnormal aggregation of amyloidß in the brain. Here, we designed a brain-permeable peptide nanofiber drug from a fragment of heat shock protein to suppress aggregation of the pathogenic proteins. To facilitate delivery of the nanofiber into the brain, a protein transduction domain from Drosophila Antennapedia was incorporated into the peptide sequence. The resulting nanofiber efficiently suppressed the cytotoxicity of amyloid ßby trapping amyloid ß onto its hydrophobic nanofiber surface. Moreover, the intravenously or intranasally injected nanofiber was delivered into the mouse brain, and improved the cognitive function of an Alzheimer transgenic mouse model. These results demonstrate the potential therapeutic utility of nanofibers for the treatment of AD.

Curcumin Derivative GT863 Inhibits Amyloid-Beta Production via Inhibition of Protein N-Glycosylation.

Amyloid-ß (Aß) peptides play a crucial role in the pathogenesis of Alzheimer's disease (AD). Aß production, aggregation, and clearance are thought to be important therapeutic targets for AD. Curcumin has been known to have an anti-amyloidogenic effect on AD. In the present study, we performed screening analysis using a curcumin derivative library with the aim of finding derivatives effective in suppressing Aß production with improved bioavailability of curcumin using CHO cells that stably express human amyloid-ß precursor protein and using human neuroblastoma SH-SY5Y cells. We found that the curcumin derivative GT863/PE859, which has been shown to have an inhibitory effect on Aß and tau aggregation in vivo, was more effective than curcumin itself in reducing Aß secretion. We further found that GT863 inhibited neither ß- nor γ-secretase activity, but did suppress γ-secretase-mediated cleavage in a substrate-dependent manner. We further found that GT863 suppressed N-linked glycosylation, including that of the γ-secretase subunit nicastrin. We also found that mannosidase inhibitors that block the mannose trimming step of N-glycosylation suppressed Aß production in a similar fashion, as was observed as a result of treatment with GT863. Collectively, these results suggest that GT863 downregulates N-glycosylation, resulting in suppression of Aß production without affecting secretase activity.

Influence of Ultra-High Hydrostatic Pressurizing Brown Rice on Cognitive Functions and Mental Health of Elderly Japanese Individuals: A 2-Year Randomized and Controlled Trial.

Brown rice contains many ingredients that might protect against cognitive decline and Alzheimer's disease. However, brown rice is very hard, difficult to cook, and is poorly digested; thus, it is difficult to eat long-term. To solve these problems, ultra-high hydrostatic pressurizing brown rice (UHHPBR) was prepared. We investigated the effects of dietary UHHPBR administration for 24 mo on cognitive function and mental health in the elderly. Healthy elderly participants (n=52) were randomized into UHHPBR and polished white rice (WR) groups. The UHHPBR group consumed 100 g of UHHPBR per day for 24 mo and the WR group consumed white rice. At baseline, and after 12 and 24 mo, cognitive functions were assessed using the Revised Hasegawa's Dementia Scale, Mini-Mental State Examination, Frontal Assessment Battery (FAB), and the Cognitive Assessment for Dementia, iPad version (CADi). Mental health condition was also assessed using the Apathy Scale and the Zung Self-Rating Depression Scale, and serum biochemical parameters were determined. From baseline to month 24, the mean change in the FAB-sub item 1 scores was higher in the UHHPBR group compared to the WR group. Furthermore, apathy scores decreased, as well as the time required to answer all questions of the CADi, and plasma epinephrine levels increased. These results indicate that a 2-y oral consumption of UHHPBR increases information processing speed (as a measure of cognitive function) and improves apathy in the elderly, suggesting a protective effect of UHHPBR administration against age-related decline in brain cognition and motivation.

Long-Term Ultra-High Hydrostatic Pressurized Brown Rice Intake Prevents Bone Mineral Density Decline in Elderly Japanese Individuals.

Bone embrittlement with aging, namely osteoporosis, is characterized by low bone mass and deterioration of bone tissue, and can lead to increased risk of fracture. The development of functional foods that can prevent geriatric diseases is in progress. Our focus was on brown rice because of its properties. An interventional study using of ultra-high hydrostatic pressurized brown rice (UHHPBR) for human has not yet been conducted. In this study, we investigated whether long-term dietary intake of UHHPBR prevents aging-related decline of bone mineral density in elderly Japanese individuals. Elderly participants (n=40; mean 73.1 y) in Iinan-cho, Shimane, Japan, were randomly divided into two groups. The UHHPBR-intake group (n=20) consumed 100 g of UHHPBR and 100 g of white rice (WR) per day for 12 mo, while the WR-intake group (n=20) consumed 200 g of WR per day. Pre- and 12-mo post-intervention, bone mineral density was evaluated by quantitative ultrasound. After 12 mo of intervention, the UHHPBR group's bone mineral density was significantly higher than the WR group's bone mineral density. Moreover, chronic intake of UHHPBR had no adverse side effects on participants. Long-term oral UHHPBR intake may have beneficial effects on bone mineral density decline and may attenuate osteoporosis in the elderly.

The Additive Effects of Low Dose Intake of Ferulic Acid, Phosphatidylserine and Curcumin, Not Alone, Improve Cognitive Function in APPswe/PS1dE9 Transgenic Mice.

Alzheimer's disease (AD) is the most common form of dementia and its prevention and treatment is a worldwide issue. Many natural components considered to be effective against AD have been identified. However, almost all clinical trials of these components for AD reported inconclusive results. We thought that multiple factors such as amyloid ß (Aß) and tau progressed the pathology of AD and that a therapeutic effect would be obtained by using multiple active ingredients with different effects. Thus, in this study, we treated ferulic acid (FA), phosphatidylserine (PS) and curcumin (Cur) in combination or alone to APPswe/PS1dE9 transgenic mice and evaluated cognitive function by Y-maze test. Consequently, only the three-ingredient group exhibited a significant improvement in cognitive function compared to the control group. In addition, we determined the amounts of Aß, brain-derived neurotrophic factor (BDNF), interleukin (IL)-1ß, acetylcholine and phosphorylated tau in the mouse brains after the treatment. In the two-ingredient (FA and PS) group, a significant decrease in IL-1ß and an increasing trend in acetylcholine were observed. In the Cur group, significant decreases in Aß and phosphorylated tau and an increasing trend in BDNF were observed. In the three-ingredient group, all of them were observed. These results indicate that the intake of multiple active ingredients with different mechanisms of action for the prevention and treatment of AD.

Highly water pressurized brown rice improves cognitive dysfunction in senescence-accelerated mouse prone 8 and reduces amyloid beta in the brain.

BACKGROUND: Alzheimer's disease (AD) is the most common form of dementia and the number of AD patients continues to increase worldwide. Components of the germ layer and bran of Brown rice (BR) help maintain good health and prevent AD. Because the germ layer and bran absorb little water and are very hard and difficult to cook, they are often removed during processing. To solve these problems, in this study, we tried to use a high-pressure (HP) technique. METHODS: We produced the highly water pressurized brown rice (HPBR) by pressurizing BR at 600 MPa, and then we fed it to an AD mouse model, senescence-accelerated mouse prone 8, to investigate the therapeutic effects of HPBR on cognitive dysfunction by Y-maze spatial memory test. RESULTS: HP treatment increased the water absorbency of BR without nutrient loss. HPBR ameliorated cognitive dysfunction and reduced the levels of amyloid-ß, which is a major protein responsible for AD, in the brain. CONCLUSIONS: These results suggest that HPBR is effective for preventing AD.

PE859, A Novel Curcumin Derivative, Inhibits Amyloid-ß and Tau Aggregation, and Ameliorates Cognitive Dysfunction in Senescence-Accelerated Mouse Prone 8.

Aggregation of amyloid-ß (Aß) and tau plays a crucial role in the onset and progression of Alzheimer's disease (AD). Therefore, the inhibition of Aß and tau aggregation may represent a potential therapeutic target for AD. Herein, we designed and synthesized both Aß and tau dual aggregation inhibitors based on the structure of curcumin and developed the novel curcumin derivative PE859. In this study, we investigated the inhibitory activity of PE859 on Aß aggregationin vitro and the therapeutic effects of PE859 on cognitive dysfunction via dual inhibition of Aß and tau aggregation in vivo. PE859 inhibited Aß aggregation in vitro and protected cultured cells from Aß-induced cytotoxicity. Furthermore, PE859 ameliorated cognitive dysfunction and reduced the amount of aggregated Aß and tau in brains of senescence-accelerated mouse prone 8 (SAMP8). These results warrant consideration of PE859 as a candidate drug for AD.

Decrease of Amyloid-ß Levels by Curcumin Derivative via Modulation of Amyloid-ß Protein Precursor Trafficking.

The abnormal production and deposition of amyloid-ß (Aß) peptides is a pathologic hallmark of Alzheimer's disease. Aß is generated from amyloid-ß protein precursor (AßPP) by two sequential proteolytic cleavage steps involving ß- and γ-secretases in the trans-Golgi network and endosomes. Since direct inhibition of secretase could induce undesirable side-effects due to inadvertent inhibition of unrelated secretase substrates, it is important to establish methods for inhibiting Aß production that do not affect secretase activity. It has been suggested that curcumin may have potent anti-amyloidogenic effect. In the present study, we evaluate the effect of curcumin derivatives on Aß production in human neuroblastoma SH-SY5Y cells and in CHO cells which stably express human AßPP (CHO-AßPP). We found that the curcumin derivative CU6 was more effective than curcumin itself in reducing Aß secretion. We further found that in SH-SY5Y cells CU6 inhibited neither ß- nor γ-secretase activity, and that increased amounts of immature forms of AßPP accumulated in the endoplasmic reticulum (ER). We also found that CU6 induced expression of the ER chaperone glucose-regulated protein 78 (GRP78), and enhanced formation of the AßPP/GRP78 complex. These results suggest that CU6 downregulates intracellular AßPP trafficking, resulting in suppression of Aß production independently of secretase activity.

Design and synthesis of curcumin derivatives as tau and amyloid ß dual aggregation inhibitors.

Alzheimer's disease (AD) is the most common form of dementia. In an AD patient's brain, senile plaques and neurofibrillary tangles, the abnormal aggregates of amyloid ß (Aß) peptide and tau protein, are observed as the two major hallmarks of this disease. To develop a new drug for treatment of AD, we have designed and synthesized a series of curcumin derivatives and evaluated their inhibitory activities against both tau and Aß aggregation. In this study, we describe the development of the more potent aggregation inhibitor 3-[(1E)-2-(1H-indol-6-yl)ethenyl]-5-[(1E)-2-[2-methoxy-4-(2-pyridylmethoxy) phenyl] ethenyl]-1H-pyrazole (compound 4, PE859). This compound has a better pharmacokinetic profile and pharmacological efficacy in vivo than curcumin, making it suitable as a drug for AD.

Toxic tau oligomer formation blocked by capping of cysteine residues with 1,2-dihydroxybenzene groups.

Neurofibrillary tangles, composed of hyperphosphorylated tau fibrils, are a pathological hallmark of Alzheimer's disease; the neurofibrillary tangle load correlates strongly with clinical progression of the disease. A growing body of evidence indicates that tau oligomer formation precedes the appearance of neurofibrillary tangles and contributes to neuronal loss. Here we show that tau oligomer formation can be inhibited by compounds whose chemical backbone includes 1,2-dihydroxybenzene. Specifically, we demonstrate that 1,2-dihydroxybenzene-containing compounds bind to and cap cysteine residues of tau and prevent its aggregation by hindering interactions between tau molecules. Further, we show that orally administered DL-isoproterenol, an adrenergic receptor agonist whose skeleton includes 1,2-dihydroxybenzene and which penetrates the brain, reduces the levels of detergent-insoluble tau, neuronal loss and reverses neurofibrillary tangle-associated brain dysfunction. Thus, compounds that target the cysteine residues of tau may prove useful in halting the progression of Alzheimer's disease and other tauopathies.

[Fundamental study of memory impairment and non-cognitive behavioral alterations in APPswe/PS1dE9 mice].

In addition to cognitive decline, Alzheimer's disease patients also exhibit non-cognitive symptoms commonly referred to as behavioral and psychological symptoms of dementia, or BPSD. These symptoms have a serious impact on the quality of life of these patients, as well as that of their caregivers, but there are currently no effective therapies. The amyloid ß-peptide (Aß) is suspected to play a central role in the cascade leading to Alzheimer's disease, but the precise mechanisms are still incompletely known. To assess the influence of Aß pathology on cognitive and non-cognitive behaviors, we examined locomotor activity, motor coordination, and spatial memory in male and female APPswePS1dE9 mice (Alzheimer's disease model, double transgenic mice expressing an amyloid precursor protein with Swedish mutation and a presenilin-1 with deletion of exon 9) at 5 months of age, when the mice had subtle Aß deposits, and again at 9 months of age, when the mice had numerous Aß deposits. Compared to wild-type mice, the male and female APPswe/PS1dE9 mice showed normal motor coordination in the rotarod test at both 5 and 9 months. In the Morris water maze test, male and female APPswe/PS1dE9 mice showed impaired spatial memory at 9 months; however, no such deficits were found at 5 months. In a locomotor activity test, male APPswe/PS1dE9 mice exhibited locomotor hyperactivity at 9 months, while females exhibited locomotor hyperactivity at both 5 and 9 months compared to the control mice. Together, these results indicate that APPswe/PS1dE9 mice developed spatial memory impairment and BPSD-like behavioral alterations resulting from Aß accumulation.

PE859, a novel tau aggregation inhibitor, reduces aggregated tau and prevents onset and progression of neural dysfunction in vivo.

In tauopathies, a neural microtubule-associated protein tau (MAPT) is abnormally aggregated and forms neurofibrillary tangle. Therefore, inhibition of the tau aggregation is one of the key approaches for the treatment of these diseases. Here, we have identified a novel tau aggregation inhibitor, PE859. An oral administration of PE859 resulted in the significant reduction of sarkosyl-insoluble aggregated tau along with the prevention of onset and progression of the motor dysfunction in JNPL3 P301L-mutated human tau transgenic mice. These results suggest that PE859 is useful for the treatment of tauopathies.

Integrin-associated protein promotes neuronal differentiation of neural stem/progenitor cells.

Neural stem/progenitor cells (NSPCs) proliferate and differentiate depending on their intrinsic properties and local environment. During the development of the mammalian nervous system, NSPCs generate neurons and glia sequentially. However, little is known about the mechanism that determines the timing of switch from neurogenesis to gliogenesis. In this study, we established a culture system in which the neurogenic potential of NSPCs is decreased in a time-dependent manner, so that short-term-cultured NSPCs differentiate into more neurons compared with long-term-cultured NSPCs. We found that short-term-cultured NSPCs express high levels of integrin-associated protein form 2 (IAP2; so-called CD47) mRNA using differential display analysis. Moreover, IAP2 overexpression in NSPCs induced neuronal differentiation of NSPCs. These findings reveal a novel mechanism by which IAP2 induces neuronal differentiation of NSPCs.

Development of dual targeting inhibitors against aggregations of amyloid-ß and tau protein.

Aggregations of both amyloid-ß (Aß) and hyper-phosphorylated tau proteins are recognized as key pathological manifestations of Alzheimer's disease (AD). Agents that inhibit both those forms of aggregation show promise as drug candidates. Seventeen oligo heteroaromatic compounds were rapidly synthesized via a one-pot, 3- or 4-component coupling procedure. Evaluations showed that compounds E16 and E18 were the most potent inhibitors of Aß and tau aggregations (E16: IC50s = 0.38, 0.29 µM against Aß, tau, respectively, E18: IC50s = 0.55, 0.30 µM against Aß, tau, respectively).

Sox21 promotes hippocampal adult neurogenesis via the transcriptional repression of the Hes5 gene.

Despite the importance of the production of new neurons in the adult hippocampus, the transcription network governing this process remains poorly understood. The High Mobility Group (HMG)-box transcription factor, Sox2, and the cell surface activated transcriptional regulator, Notch, play important roles in CNS stem cells. Here, we demonstrate that another member of the SoxB (Sox1/Sox2/Sox3) transcription factor family, Sox21, is also a critical regulator of adult neurogenesis in mouse hippocampus. Loss of Sox21 impaired transition of progenitor cells from type 2a to type 2b, thereby reducing subsequent production of new neurons in the adult dentate gyrus. Analysis of the Sox21 binding sites in neural stem/progenitor cells indicated that the Notch-responsive gene, Hes5, was a target of Sox21. Sox21 repressed Hes5 gene expression at the transcriptional level. Simultaneous overexpression of Hes5 and Sox21 revealed that Hes5 was a downstream effector of Sox21 at the point where the Notch and Sox pathways intersect to control the number of neurons in the adult hippocampus. Therefore, Sox21 controls hippocampal adult neurogenesis via transcriptional repression of the Hes5 gene.

Glycogen synthase kinase-3ß activation mediates rotenone-induced cytotoxicity with the involvement of microtubule destabilization.

Rotenone, a mitochondrial complex I inhibitor, has been used to generate animal and cell culture models of Parkinson's disease. Recent studies suggest that microtubule destabilization causes selective dopaminergic neuronal loss. In this study, we investigated glycogen synthase kinase-3ß (GSK3ß) involvement in rotenone-induced microtubule destabilization. Rotenone-induced cytotoxicity in SH-SY5Y cells was attenuated by the GSK3ß inhibitor SB216763. Tau, a microtubule-associated protein and substrate for GSK3ß, has been implicated in the pathogenesis of tauopathies such as Alzheimer's disease. Rotenone induced an increase in phosphorylated tau, the effect of which was attenuated by concomitant treatment with SB216763. Rotenone treatment also decreased tau expression in the microtubule fraction and increased tau expression in the cytosol fraction. These effects were suppressed by SB216763, which suggests that rotenone reduces the capacity of tau to bind microtubules. Rotenone treatment increased the amount of free tubulin and reduced the amount of polymerized tubulin, indicating that rotenone destabilizes microtubules. Rotenone-induced microtubule destabilization was suppressed by SB216763 and taxol, a microtubule stabilizer. Taxol prevented rotenone-induced cytotoxicity and morphological changes. Taken together, these results suggest that rotenone-induced cytotoxicity is mediated by microtubule destabilization via GSK3ß activation, and that microtubule destabilization is caused by reduction in the binding capacity of tau to microtubules, which is a result of tau phosphorylation via GSK3ß activation.

Isolation, identification, and biological evaluation of Nrf2-ARE activator from the leaves of green perilla (Perilla frutescens var. crispa f. viridis).

The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway is a cellular defense system against oxidative stress. Activation of this pathway increases expression of antioxidant enzymes. Epidemiological studies have demonstrated that the consumption of fruits and vegetables is associated with reduced risk of contracting a variety of human diseases. The aim of this study is to find Nrf2-ARE activators in dietary fruits and vegetables. We first attempted to compare the potency of ARE activation in six fruit and six vegetables extracts. Green perilla (Perilla frutescens var. crispa f. viridis) extract exhibited high ARE activity. We isolated the active fraction from green perilla extract through bioactivity-guided fractionation. Based on nuclear magnetic resonance and mass spectrometric analysis, the active ingredient responsible for the ARE activity was identified as 2',3'-dihydroxy-4',6'-dimethoxychalcone (DDC). DDC induced the expression of antioxidant enzymes, such as γ-glutamylcysteine synthetase (γ-GCS), NAD(P)H: quinone oxidoreductase-1 (NQO1), and heme oxygenase-1. DDC inhibited the formation of intracellular reactive oxygen species and the cytotoxicity induced by 6-hydroxydopamine. Inhibition of the p38 mitogen-activated protein kinase pathway abolished ARE activation, the induction of γ-GCS and NQO1, and the cytoprotective effect brought about by DDC. Thus, this study demonstrated that DDC contained in green perilla enhanced cellular resistance to oxidative damage through activation of the Nrf2-ARE pathway.

Invasion precedes tumor mass formation in a malignant brain tumor model of genetically modified neural stem cells.

Invasiveness, cellular atypia, and proliferation are hallmarks of malignant gliomas. To effectively target each of these characteristics, it is important to understand their sequence during tumorigenesis. However, because most gliomas are diagnosed at an advanced stage, the chronology of gliomagenesis milestones is not well understood. The aim of the present study was to determine the onset of these characteristics during tumor development. Brain tumor-initiating cells (BTICs) were established by overexpressing H-Ras(V12) in normal neural stem/progenitor cells isolated from the subventricular zone of adult mice harboring a homozygous deletion of the Ink4a/Arf locus. High-grade malignant brain tumors were then created by orthotopic implantation of 10(5) BTICs into the forebrain of 6-week-old wild-type mice. Micewere killed every week for 5 weeks, and tumors were assessed for cellular atypia, proliferation, hemorrhage, necrosis, and invasion. All mice developed highly invasive, hypervascular glioblastoma-like tumors. A 100% penetrance rate and a 4-week median survival were achieved. Tumor cell migration along fiber tracts started within days after implantation and was followed by perivascular infiltration of tumor cells with marked recruitment of reactive host cells. Next, cellular atypia became prominent. Finally, mass proliferation and necrosis were observed in the last stage of the disease. Video monitoring of BTICs in live brain slices confirmed the early onset of migration, as well as the main cell migration patterns. Our results showed that perivascular and intraparenchymal tumor cell migration precede tumor mass formation in the adult brain, suggesting the need for an early and sustained anti-invasion therapy.