70 results on '"Yuyama K"'
Search Results
2. Effect of impurity deposition layer formation on D retention in LHD plasma exposed W
- Author
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Oya, Y., Fujita, H., Hu, C., Uemura, Y., Sakurada, S., Yuyama, K., Li, X., Hatano, Y., Yoshida, N., Watanabe, H., Nobuta, Y., Yamauchi, Y., Tokitani, M., Masuzaki, S., and Chikada, T.
- Published
- 2016
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3. Nanoparticle preparation of quinacridone and β-carotene using near-infrared laser ablation of their crystals
- Author
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Yuyama, K., Sugiyama, T., Asahi, T., Ryo, S., Oh, I., and Masuhara, H.
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- 2010
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4. Response to fertilization and nutrient deficiency diagnostics in peach palm in Central Amazonia
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Ares, A., Falcao, N., Yuyama, K., Yost, R.S., and Clement, C.R.
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- 2003
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5. Early Evaluation of Camu-Camu Subsamples in Transition Savanna/Forest Area
- Author
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ALMEIDA, L. F. P. de, YUYAMA, K., CHAGAS, E. A., ALBUQUERQUE, T. C. S. de, QUEIRO, F. B. D. de, RODRIGUEZ, C. A., EDVAN ALVES CHAGAS, CPAF-RR, TERESINHA COSTA S DE ALBUQUERQUE, CPAF-RR, and FERNANDO BARRETO D DE QUEIROZ, CPAF-RR.
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plant growth ,Upland production ,Myrciaria Dubia - Published
- 2014
6. Generation of hexagonal close-packed ring-shaped structures using an optical vortex
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Kawaguchi Haruki, Umesato Kei, Takahashi Kanta, Yamane Keisaku, Morita Ryuji, Yuyama Ken-ichi, Kawano Satoyuki, Miyamoto Katsuhiko, Kohri Michinari, and Omatsu Takashige
- Subjects
laser induced forward transfer ,nanostructures ,optical vortex ,orbital angular momentum ,singular optics ,structural colors ,Physics ,QC1-999 - Abstract
An optical vortex possesses a ring-shaped spatial profile and orbital angular momentum (OAM) owing to its helical wavefront. This form of structured light has garnered significant attention in recent years, and it has enabled new investigations in fundamental physics and applications. One such exciting application is laser-based material transfer for nano-/micro-fabrication. In this work, we demonstrate the application of a single-pulse optical vortex laser beam for direct printing of ring-shaped structures composed of hexagonal close-packed, mono-/multi-layered nanoparticles which exhibit ‘structural color’. We compare and contrast the interaction of the vortex beam with both dielectric and metallic nanoparticles and offer physical insight into how the OAM of vortex beams interacts with matter. The demonstrated technique holds promise for not only photonic-based nano-/micro-fabrication, but also as a means of sorting particles on the nanoscale, a technology which we term ‘optical vortex nanoparticle sorting’.
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- 2021
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7. Contribution of the institutions in the Northern region of Brazil to the development of plant cultivars and their impact on agriculture
- Author
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SOUZA, A. das G. C. de, SOUSA, N. R., LOPES, R., ATROCH, A. L., BARCELOS, E., CORDEIRO, E., OLIVEIRA, M. do S. P. de, ALVES, R. M., FARIAS NETO, J. T. de, NODA, H., SILVA FILHO, D. F., YUYAMA, K., ALMEIDA, C. M. V. C. de, LOPES, M. T. G., OHASHI, S. T., APARECIDA DAS GRACAS C DE SOUZA, CPAA, NELCIMAR REIS SOUSA, CPAA, RICARDO LOPES, CPAA, ANDRE LUIZ ATROCH, CPAA, EDSON BARCELOS DA SILVA, CPAA, EVERTON RABELO CORDEIRO, CPAA, MARIA DO SOCORRO P DE OLIVEIRA, CPATU, RAFAEL MOYSES ALVES, CPATU, JOAO TOME DE FARIAS NETO, CPATU, HIROSHI NODA, INPA, DANILO F. SILVA FILHO, INPA, KAORU YUYAMA, INPA, CAIO MÁRCIO VASCONCELLOS CORDEIRO DE ALMEIDA, CEPLAC, MARIA TERESA GOMES LOPES, UNIVERSIDADE FEDERAL RURAL DA AMAZÔNIA, and SELMA TOYOKO OHASHI, UNIVERSIDADE FEDERAL RURAL DA AMAZÔNIA.
- Subjects
plant breeding ,Native species ,Amazon region - Abstract
This paper describes the development of breeding programs in northern Brazil and their main impacts on agriculture. Their contribution to the breeding of the species palm oil, acai fruit, cacao, cupuaçu, guarana, tomato, camu-camu, cocona, peach palm, and rubber was laid out in detail. Advances in breeding programs of institutions such as Embrapa, Ceplac, Inpa, and Universities require investments in infrastructure and in human and financial resources to ensure continuity and efficiency in economic, social and environmental gains. The improvement of native species, the main focus of the breeding programs of the institutions in the Northern region of Brazil, is a form of exploiting the Amazonian biodiversity for the benefit of society. Therefore, policies to foster research institutions should be a subject of deliberation and action of the scientific and technological community in Brazil.
- Published
- 2012
8. A perovskite based plug and play AC photovoltaic device with ionic liquid induced transient opto-electronic conversion.
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Karak, S., Nanjo, C., Odaka, M., Yuyama, K., Masuda, G., Matsushita, M. M., and Awaga, K.
- Abstract
This study reports on the implementation of transient opto-electronic conversion for energy harvesting associated with induced electric double layers (EDLs) at perovskite/ionic liquid interfaces. High speed alternating current (AC) producing photovoltaic devices are successfully fabricated and demonstrated with a device architecture as indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/perovskite (CH
3 NH3 PbI3 )/[6,6]-phenyl-C61 -butyric acid methyl ester (PCBM)/ionic liquid/aluminum (Al). 52% peak external quantum efficiency with a maximum responsivity of 228 mA W−1 has been observed with a relatively uniform response over the whole visible solar spectrum. Such a new class of devices can produce photocurrent under both light “ON” and “OFF” cycles in response to a pulsed signal. This unique feature makes them inherently capable of producing AC power when illuminated under modulated solar radiation. The large (∼90 dB) linear dynamic range (LDR) of the devices confirms their efficient power conversion capabilities even from very low intensity light sources. At 50 Hz modulation frequency, a photovoltaic device with ∼2% overall effective AC power conversion efficiency, which further increases and gets saturated around ∼3% beyond 160 Hz modulation frequency, is also successfully realized. The mechanism of the AC effect formation is explained based on the energy band diagram and an equivalent resistance (R)–capacitance (C) circuit of the devices. [ABSTRACT FROM AUTHOR]- Published
- 2016
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9. Dynamic PIV Flow Field and Sound Study of the Bi-leaflet Mitral Prostheses.
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Kim, Sun I., Suh, Tae Suk, Magjarevic, R., Nagel, J. H., Akutsu, Toshinosuke, Saito, J., Mori, K., Imai, R., Suzuki, T., Yuyama, K., and Miura, K.
- Abstract
The St. Jude Medical (SJM) and the On-X valves with straight leaflets and the Jyros (JR) and the MIRA valves with curved leaflets were tested in the mitral position under pulsatile-flow condition. Dynamic PIV system was employed to analyze the flow field affected by the leaflet shapes, and valve designs. All valves show large turbulent stresses during accelerating flow phase. Older designs, the SJM and the JR valves deflected the flow during accelerating flow phase. Newer designs, the On-X and the MIRA valves deflected less Straight leaflets of the SJM valve do not deflect the flow too much when it fully opens, while curved leaflets of the Jyros valve deflects the flow sideway. The SJM valve generates strong downward flow immediately downstream of the mitral valve while the JR valve generates strong peripherally downward flow, both generating twin circulatory flow with different characteristics. The On-X valve has strong centrally downwards flow due to its large opening angle and flared inlet shape. The MIRA valve also has strong downwards-central flow, but divert three-dimensionally due to its peripherally curved leaflets. Flow field pattern differences during the peak flow phase seem to affect closing behavior of the bi-leaflet valves, thus, affecting the closing valve sound level. Old design of the SJM valve and newer design of the MIRA and the On-X valves exhibited larger closing sound. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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10. Physiological and pathological roles of exosomes in the nervous system
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Yuyama Kohei and Igarashi Yasuyuki
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exosome ,glial cell ,neurodegenerative disease ,neuron ,Biology (General) ,QH301-705.5 - Abstract
Exosomes represent a subtype of extracellular nanovesicles that are generated from the luminal budding of limiting endosomal membranes and subsequent exocytosis. They encapsulate or associate with obsolete molecules to eliminate or to transfer their cargos in intercellular communication. The exosomes are also released and transported between neurons and glia in the nervous system, having a broad impact on nerve development, activation and regeneration. Accumulating evidence suggests that the exosomes are attributed to the pathogenesis of several neurodegenerative diseases such as prion disease, Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, as well as aging, in which the exosomes lack the capacity for cellular self-repair and spread their enclosed pathological agents among neurons. In this article, we review the current proposed functions of exosomes in physiological and pathological processes in the nervous system.
- Published
- 2016
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11. Structures and dynamics of glycosphingolipid-containing lipid mixtures as raft models of plasma membrane.
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Hirai, M., Koizumi, M., Hirai, H., Hayakawa, T., Yuyama, K., Suzuki, N., and Kasahara, K.
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- 2005
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12. Branched-chain amino acids and specific phosphatidylinositols are plasma metabolite pairs associated with menstrual pain severity.
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Sato A, Yuyama K, Ichiba Y, Kakizawa Y, and Sugiura Y
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- Humans, Female, Adult, Young Adult, Severity of Illness Index, Pain Measurement methods, Amino Acids, Branched-Chain blood, Biomarkers blood, Dysmenorrhea blood, Metabolomics methods, Phosphatidylinositols blood
- Abstract
Menstrual pain affects women's quality of life and productivity, yet objective molecular markers for its severity have not been established owing to the variability in blood levels and chemical properties of potential markers such as plasma steroid hormones, lipid mediators, and hydrophilic metabolites. To address this, we conducted a metabolomics study using five analytical methods to identify biomarkers that differentiate menstrual pain severity. This study included 20 women, divided into mild (N = 12) and severe (N = 8) pain groups based on their numerical pain rating scale. We developed pretreatment procedures that allowed all analyses from only 100 µL of finger-prick blood collected across the menstrual cycle. Among the 692 quantified metabolites, branched-chain amino acids and specific phosphatidylinositol (PI), especially PI(36:2), were identified as potential biomarkers. Furthermore, the ratio of PI(36:2) to each BCAA or total BCAA effectively discriminated between the severity levels of menstrual pain. These ratios correlated positively with NPRS, indicating high accuracy in pain assessment. This study highlights the potential of small molecular markers to objectively assess menstrual pain severity, aiding evidence-based support and intervention., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: This study was conducted in accordance with the Declaration of Helsinki 1964, and the study protocol was approved by the local ethics committee (Approval No. 329) at the Lion Corporation, Tokyo, Japan. Informed consent: All participants in this study provided informed consent. All participants in this study are employees of the Lion Corporation. When obtaining consent to participate in this study, the authors explained that they could withdraw from this study at any time and for any reason, and that they would not be treated unfavourably if they withdrew their consent. Furthermore, a personal information manager was assigned separately from the authors to handle only the various types of anonymized data to fully protect the privacy of the participant., (© 2025. The Author(s).)
- Published
- 2025
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13. Detection of new metabolites of risperidone in the solid tissues and body fluids obtained from two cadavers by high resolution tandem mass spectrometry.
- Author
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Minakata K, Nozawa H, Yamagishi I, Yuyama K, Suzuki M, Kitamoto T, Kondo M, Suzuki O, and Hasegawa K
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- Humans, Male, Liver chemistry, Liver metabolism, Forensic Toxicology methods, Female, Tissue Distribution, Brain Chemistry, Body Fluids chemistry, Chromatography, Liquid, Risperidone analysis, Risperidone metabolism, Antipsychotic Agents, Cadaver, Bile chemistry, Tandem Mass Spectrometry, Kidney chemistry, Kidney metabolism, Pericardial Fluid chemistry, Pericardial Fluid metabolism
- Abstract
Risperidone (Ris) is a second-generation antipsychotic that belongs to the chemical class of benzisoxazole derivatives. 9-Hydroxy (9OH-) Ris is well known among the six reported metabolites of Ris and had been examined using not only blood but also other matrices, but the other five metabolites reported such as benzisoxazole ring-cleaved Ris (c-Ris) and c-9OH-Ris had been detected only in blood, urine and feces. In the present work, large peaks of c-Ris and c-9OH-Ris were detected in the liver, kidney, cerebrum, blood, pericardial fluid, bile and urine obtained from two cadavers. There is a potential that c-Ris and c-9OH-Ris will be good markers to prove Ris consumption in forensic toxicology cases. For example, the peak ratios of c-Ris against the parent Ris in the kidney and blood were as high as 3.9 and 3.6 in cadaver 1; and 7.0 and 7.9 in cadaver 2, respectively. In addition to the previously reported six metabolites, five new metabolites such as dehydrogenated-Ris, 7-keto-Ris and three benzisoxazole ring-cleaved metabolites were disclosed in the present work, and the pathways for the totally eleven metabolites detected in human solid tissues and body fluids have also been proposed, because such pathways were neither reported nor discussed previously., Competing Interests: Declaration of Competing Interest The authors declare that there are no financial or other relationships that could lead to a conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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14. Quantification of risperidone and paliperidone by liquid chromatography-tandem mass spectrometry in biological fluids and solid tissues obtained from two deceased using the standard addition method.
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Nozawa H, Minakata K, Hasegawa K, Yamagishi I, Miyoshi N, Yuyama K, Suzuki M, Kitamoto T, Kondo M, and Suzuki O
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- Humans, Chromatography, Liquid methods, Male, Body Fluids chemistry, Middle Aged, Female, Paliperidone Palmitate analysis, Paliperidone Palmitate pharmacokinetics, Tandem Mass Spectrometry methods, Risperidone analysis, Antipsychotic Agents
- Abstract
Risperidone (RIS) is an atypical antipsychotic agent and its 9-hydroxylated metabolite named paliperidone (PAL) also has pharmacological properties similar to that of RIS. Quantifications of RIS and PAL in authentic human biological fluids and solid tissues by liquid chromatography (LC)-tandem mass spectrometry (MS/MS) have not been reported yet although those in plasma (and blood) were reported abundantly. In the present work, a quantification method for RIS and PAL based on the standard addition method was devised and validated for the human fluid and solid tissue specimens. RIS and PAL in biological fluids were quantified only after their dilution and deproteinization. The concentrations of RIS and PAL in the heart whole blood, pericardial fluid, stomach contents, bile, urine, liver, kidney and cerebrum were determined for a deceased who had been treated with RIS therapeutically, and also a deceased who had ingested RIS with other drugs intentionally. To our knowledge, this is the first report on the quantification of RIS and PAL by LC-MS/MS in the authentic human tissues and biological fluids., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2024
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15. Odor identification score as an alternative method for early identification of amyloidogenesis in Alzheimer's disease.
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Igeta Y, Hemmi I, Yuyama K, and Ouchi Y
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- Humans, Amyloid beta-Peptides cerebrospinal fluid, Odorants, tau Proteins cerebrospinal fluid, Biomarkers cerebrospinal fluid, Apolipoprotein E4 genetics, Peptide Fragments cerebrospinal fluid, Alzheimer Disease diagnosis, Alzheimer Disease cerebrospinal fluid, Cognitive Dysfunction diagnosis, Cognitive Dysfunction cerebrospinal fluid
- Abstract
A simple screening test to identify the early stages of Alzheimer's disease (AD) is urgently needed. We investigated whether odor identification impairment can be used to differentiate between stages of the A/T/N classification (amyloid, tau, neurodegeneration) in individuals with amnestic mild cognitive impairment or AD and in healthy controls. We collected data from 132 Japanese participants visiting the Toranomon Hospital dementia outpatient clinic. The odor identification scores correlated significantly with major neuropsychological scores, regardless of apolipoprotein E4 status, and with effective cerebrospinal fluid (CSF) biomarkers [amyloid β 42 (Aβ42) and the Aβ42/40 and phosphorylated Tau (p-Tau)/Aβ42 ratios] but not with ineffective biomarkers [Aβ40 and the p-Tau/total Tau ratio]. A weak positive correlation was observed between the corrected odor identification score (adjusted for age, sex, ApoE4 and MMSE), CSF Aβ42, and the Aβ42/40 ratio. The odor identification score demonstrated excellent discriminative power for the amyloidogenesis stage , according to the A/T/N classification, but was unsuitable for differentiating between the p-Tau accumulation and the neurodegeneration stages. After twelve odor species were analyzed, a version of the score comprising only four odors-India ink, wood, curry, and sweaty socks-proved highly effective in identifying AD amyloidogenesis, showing promise for the screening of preclinical AD., (© 2024. The Author(s).)
- Published
- 2024
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16. Extracellular vesicle proteome unveils cathepsin B connection to Alzheimer's disease pathogenesis.
- Author
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Yuyama K, Sun H, Fujii R, Hemmi I, Ueda K, and Igeta Y
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- Humans, Proteome metabolism, Cathepsin B metabolism, Proteomics, Biomarkers, Amyloid beta-Peptides metabolism, tau Proteins metabolism, Alzheimer Disease pathology, Extracellular Vesicles metabolism
- Abstract
Extracellular vesicles (EVs) are membrane vesicles that are released extracellularly and considered to be implicated in the pathogenesis of neurodegenerative diseases including Alzheimer's disease. Here, CSF EVs of 16 ATN-classified cases were subjected to quantitative proteome analysis. In these CSF EVs, levels of 11 proteins were significantly altered during the ATN stage transitions (P < 0.05 and fold-change > 2.0). These proteins were thought to be associated with Alzheimer's disease pathogenesis and represent candidate biomarkers for pathogenic stage classification. Enzyme-linked immunosorbent assay analysis of CSF and plasma EVs revealed altered levels of cathepsin B (CatB) during the ATN transition (seven ATN groups in validation set, n = 136). The CSF and plasma EV CatB levels showed a negative correlation with CSF amyloid-β42 concentrations. This proteomic landscape of CSF EVs in ATN classifications can depict the molecular framework of Alzheimer's disease progression, and CatB may be considered a promising candidate biomarker and therapeutic target in Alzheimer's disease amyloid pathology., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2024
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17. Stereochemistry-activity relationship of ceramide-induced exosome production to clear amyloid-β in Alzheimer's disease.
- Author
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Abdelrasoul M, Yuyama K, Swamy MMM, Murai Y, and Monde K
- Subjects
- Humans, Ceramides, Stereoisomerism, Amyloid beta-Peptides, Alzheimer Disease drug therapy, Exosomes
- Abstract
Stereochemistry has a substantial impact on the biological activity of various drugs. We investigated the role of stereochemistry of ceramides in inducing the production of exosomes, a type of extracellular vesicle, from neuronal cells, with a potential benefit in improving the clearance of amyloid-β (Aβ), a causal agent of Alzheimer's disease. A stereochemical library of diverse ceramides with different tail lengths was synthesized with the purpose of varying stereochemistry (D-erythro: DE, D-threo: DT, L-erythro: LE, L-threo: LT) and hydrophobic tail length (C6, C16, C18, C24). The exosome levels were quantified using TIM4-based exosome enzyme-linked immunosorbent assay after concentrating the conditioned medium using centrifugal filter devices. The results revealed a pivotal role of stereochemistry in determining the biological activity of ceramide stereoisomers, with the superiority of those based on DE and DT stereochemistry with C16 and C18 tails, which demonstrated significantly higher exosome production, without a significant change in the particle size of the released exosomes. In transwell experiments with Aβ-expressed neuronal and microglial cells, DE- and DT-ceramides with C16 and C18 tails significantly decreased extracellular Aβ levels. The results reported here are promising in the design of non-classic therapies for the treatment of Alzheimer's disease., (© 2023 Wiley Periodicals LLC.)
- Published
- 2023
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18. Immuno-digital invasive cleavage assay for analyzing Alzheimer's amyloid ß-bound extracellular vesicles.
- Author
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Yuyama K, Sun H, Igarashi Y, Monde K, Hirase T, Nakayama M, and Makino Y
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- Animals, Humans, Infant, Mice, Amyloid metabolism, Amyloid beta-Peptides metabolism, Amyloidogenic Proteins metabolism, Biomarkers metabolism, Cholera Toxin metabolism, G(M1) Ganglioside metabolism, Gangliosides metabolism, Mice, Transgenic, Oligonucleotides metabolism, Alzheimer Disease genetics, Amyloidosis, Extracellular Vesicles metabolism
- Abstract
Background: The protracted preclinical stage of Alzheimer's disease (AD) provides the opportunity for early intervention to prevent the disease; however, the lack of minimally invasive and easily detectable biomarkers and their measurement technologies remain unresolved. Extracellular vesicles (EVs) are nanosized membrane vesicles released from a variety of cells and play important roles in cell-cell communication. Neuron-derived and ganglioside-enriched EVs capture amyloid-ß protein, a major AD agent, and transport it into glial cells for degradation; this suggests that EVs influence Aß accumulation in the brain. EV heterogeneity, however, requires the use of a highly sensitive technique for measuring specific EVs in biofluid. In this study, immuno-digital invasive cleavage assay (idICA) was developed for quantitating target-intact EVs., Methods: EVs were captured onto ganglioside GM1-specific cholera toxin B subunit (CTB)-conjugated magnetic beads and detected with a DNA oligonucleotide-labeled Aß antibody. Fluorescence signals for individual EVs were then counted using an invasive cleavage assay (ICA). This idICA examines the Aß-bound and GM1-containing EVs isolated from the culture supernatant of human APP-overexpressing N2a (APP-N2a) cells and APP transgenic mice sera., Results: The idICA quantitatively detected Aß-bound and GM1-containing EVs isolated from culture supernatants of APP-N2a cells and sera of AD model mice. The idICA levels of Aß-associated EVs in blood gradually increased from 3- to 12-month-old mice, corresponding to the progression of Aß accumulations in the brain of AD model mice., Conclusions: The present findings suggest that peripheral EVs harboring Aß and GM1 reflect Aß burden in mice. The idICA is a valuable tool for easy quantitative detection of EVs as an accessible biomarker for preclinical AD diagnosis., (© 2022. The Author(s).)
- Published
- 2022
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19. Linking glycosphingolipids to Alzheimer's amyloid-ß: extracellular vesicles and functional plant materials.
- Author
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Yuyama K and Igarashi Y
- Subjects
- Amyloid metabolism, Amyloid beta-Peptides metabolism, Animals, Ceramides metabolism, Glucosylceramides, Glycosphingolipids metabolism, Humans, Mice, Alzheimer Disease metabolism, Extracellular Vesicles metabolism
- Abstract
Glycosphingolipids (GSLs) are a specialized class of membrane lipids composed of a ceramide and a carbohydrate head group. GSLs are localized in cell membranes and were recently found to be enriched in the membrane of neuron-derived exosomes, which are a type of extracellular vesicle. Our studies demonstrated that exosomal GSLs may be associated with the amyloid-ß (Aß) peptide, a principal agent of Alzheimer's disease (AD), and act to clear Aß by transporting Aß into brain phagocytic microglia. In this review, we summarize and discuss the function of exosomal GSLs in Aß homeostasis in AD pathology. Improvement in Aß clearance is a potent strategy for AD prevention and therapy. Dietary glucosylceramides (GlcCer) isolated from plants are absorbed into the body as various metabolites, including ceramides. Our recent work demonstrated that dietary GlcCer accelerates neuronal exosome production, which facilitates Aß clearance in mice. Furthermore, studies of AD model mice and human clinical trials have found that oral administration of plant-type GlcCer attenuates the Aß burden in the brain. We also introduce the development of plant-type GlcCer as functional food materials to prevent AD., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
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20. Evaluation of Plant Ceramide Species-Induced Exosome Release from Neuronal Cells and Exosome Loading Using Deuterium Chemistry.
- Author
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Murai Y, Honda T, Yuyama K, Mikami D, Eguchi K, Ukawa Y, Usuki S, Igarashi Y, and Monde K
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- Amyloid beta-Peptides pharmacology, Animals, Ceramides pharmacology, Deuterium, Fatty Acids pharmacology, Mammals, Mice, Alzheimer Disease pathology, Exosomes pathology
- Abstract
The extracellular accumulation of aggregated amyloid-β (Aβ) in the brain leads to the early pathology of Alzheimer's disease (AD). The administration of exogenous plant-type ceramides into AD model mice can promote the release of neuronal exosomes, a subtype of extracellular vesicles, that can mediate Aβ clearance. In vitro studies showed that the length of fatty acids in mammalian-type ceramides is crucial for promoting neuronal exosome release. Therefore, investigating the structures of plant ceramides is important for evaluating the potential in releasing exosomes to remove Aβ. In this study, we assessed plant ceramide species with D- erythro -(4 E ,8 Z )-sphingadienine and D- erythro -(8 Z )-phytosphingenine as sphingoid bases that differ from mammalian-type species. Some plant ceramides were more effective than mammalian ceramides at stimulating exosome release. In addition, using deuterium chemistry-based lipidomics, most exogenous plant ceramides were confirmed to be derived from exosomes. These results suggest that the ceramide-dependent upregulation of exosome release may promote the release of exogenous ceramides from cells, and plant ceramides with long-chain fatty acids can effectively release neuronal exosomes and prevent AD pathology.
- Published
- 2022
- Full Text
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21. Ceramide Metabolism Regulated by Sphingomyelin Synthase 2 Is Associated with Acquisition of Chemoresistance via Exosomes in Human Leukemia Cells.
- Author
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Taniguchi M, Nagaya S, Yuyama K, Kotani A, Igarashi Y, and Okazaki T
- Subjects
- Ceramides metabolism, Doxorubicin pharmacology, Drug Resistance, Neoplasm, Humans, Sphingomyelins metabolism, Transferases (Other Substituted Phosphate Groups), Exosomes metabolism, Leukemia, MicroRNAs genetics
- Abstract
Ceramide levels controlled by the sphingomyelin (SM) cycle have essential roles in cancer cell fate through the regulation of cell proliferation, death, metastasis, and drug resistance. Recent studies suggest that exosomes confer cancer malignancy. However, the relationship between ceramide metabolism and exosome-mediated cancer malignancy is unclear. In this study, we elucidated the role of ceramide metabolism via the SM cycle in exosomes and drug resistance in human leukemia HL-60 and adriamycin-resistant HL-60/ADR cells. HL-60/ADR cells showed significantly increased exosome production and release compared with parental chemosensitive HL-60 cells. In HL-60/ADR cells, increased SM synthase (SMS) activity reduced ceramide levels, although released exosomes exhibited a high ceramide ratio in both HL-60- and HL-60/ADR-derived exosomes. Overexpression of SMS2 but not SMS1 suppressed intracellular ceramide levels and accelerated exosome production and release in HL-60 cells. Notably, HL-60/ADR exosomes conferred cell proliferation and doxorubicin resistance properties to HL-60 cells. Finally, microRNA analysis in HL-60 and HL-60/ADR cells and exosomes showed that miR-484 elevation in HL-60/ADR cells and exosomes was associated with exosome-mediated cell proliferation. This suggests that intracellular ceramide metabolism by SMS2 regulates exosome production and release, leading to acquisition of drug resistance and enhanced cell proliferation in leukemia cells., Competing Interests: The authors declare no conflict of interest.
- Published
- 2022
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22. Intracerebral Transplantation of Mesenchymal Stromal Cell Compounded with Recombinant Peptide Scaffold against Chronic Intracerebral Hemorrhage Model.
- Author
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Takamiya S, Kawabori M, Kitahashi T, Nakamura K, Mizuno Y, Yasui H, Kuge Y, Tanimori A, Takamatsu Y, Yuyama K, Shichinohe H, and Fujimura M
- Abstract
Background: Due to the lack of effective therapies, stem cell transplantation is an anticipated treatment for chronic intracerebral hemorrhage (ICH), and higher cell survival and engraftment are considered to be the key for recovery. Mesenchymal stromal cells (MSCs) compounded with recombinant human collagen type I scaffolds (CellSaics) have a higher potential for cell survival and engraftment compared with solo-MSCs, and we investigated the validity of intracerebral transplantation of CellSaic in a chronic ICH model., Methods: Rat CellSaics (rCellSaics) were produced by rat bone marrow-derived MSC (rBMSCs). The secretion potential of neurotrophic factors and the cell proliferation rate were compared under oxygen-glucose deprivation (OGD) conditions. rCellSaics, rBMSCs, or saline were transplanted into the hollow cavity of a rat chronic ICH model. Functional and histological analyses were evaluated, and single-photon emission computed tomography for benzodiazepine receptors was performed to monitor sequential changes in neuronal integrity. Furthermore, human CellSaics (hCellSaics) were transplanted into a chronic ICH model in immunodeficient rats. Antibodies neutralizing brain-derived neurotrophic factor (BDNF) were used to elucidate its mode of action., Results: rCellSaics demonstrated a higher secretion potential of trophic factors and showed better cell proliferation in the OGD condition. Animals receiving rCellSaics displayed better neurological recovery, higher intracerebral BDNF, and better cell engraftment; they also showed a tendency for less brain atrophy and higher benzodiazepine receptor preservation. hCellSaics also promoted significant functional recovery, which was reversed by BDNF neutralization., Conclusion: Intracerebral transplantation of CellSaics enabled neurological recovery in a chronic ICH model and may be a good option for clinical application., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2022 Soichiro Takamiya et al.)
- Published
- 2022
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23. Penta-deuterium-labeled 4E, 8Z-sphingadienine for rapid analysis in sphingolipidomics study.
- Author
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Murai Y, Yuyama K, Mikami D, Igarashi Y, and Monde K
- Subjects
- Animals, Deuterium, Ethanolamines, HEK293 Cells, Humans, Mammals metabolism, Rubiaceae metabolism, Sphingolipids chemistry
- Abstract
The use of deuterium-incorporated bioactive compounds is an efficient method for tracing their metabolic fate and for quantitative analysis by mass spectrometry without complicated HPLC separation even if their amounts are extremely small. Plant sphingolipids and their metabolites, which have C4, 8-olefins on a common backbone as a sphingoid base, show unique and fascinating bioactivities compared to those of sphingolipids in mammals. However, the functional and metabolic mechanisms of exogenous plant sphingolipids have not been elucidated due to the difficulty in distinguishing exogenous sphingolipids from endogenous sphingolipids having the same polarity and same molecular weight by mass spectrometric analysis. Their roles might be elucidated by the use of deuterated probes with original biological and physicochemical properties. In this study, we designed (2S,3R,4E,8Z)-2-aminooctadeca-4,8-diene-17,17,18,18,18-d
5 -1,3-diol (penta-deuterium-labeled 4E, 8Z-sphingadienine) as a tracer for exogenous metabolic studies. In addition, the sphingadienine was confirmed to be metabolized in HEK293 cells and showed distinct peaks in mass spectrometric analysis., (Copyright © 2022 Elsevier B.V. All rights reserved.)- Published
- 2022
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24. Konjac Ceramide (kCer)-Mediated Signal Transduction of the Sema3A Pathway Promotes HaCaT Keratinocyte Differentiation.
- Author
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Usuki S, Tamura N, Tamura T, Yuyama K, Mikami D, Mukai K, and Igarashi Y
- Abstract
Histamines suppress epidermal keratinocyte differentiation. Previously, we reported that konjac ceramide (kCer) suppresses histamine-stimulated cell migration of HaCaT keratinocytes. kCer specifically binds to Nrp1 and does not interact with histamine receptors. The signaling mechanism of kCer in HaCaT cells is also controlled by an intracellular signaling cascade activated by the Sema3A-Nrp1 pathway. In the present study, we demonstrated that kCer treatment induced HaCaT keratinocyte differentiation after migration of immature cells. kCer-induced HaCaT cell differentiation was accompanied by some features of keratinocyte differentiation markers. kCer induced activating phosphorylation of p38MAPK and c-Fos, which increased the protein levels of involucrin that was the latter differentiation marker. In addition, we demonstrated that the effects of both kCer and histamines are regulated by an intracellular mechanism of Rac1 activation/RhoA inhibition downstream of the Sema3A/Nrp1 receptor and histamine/GPCR pathways. In summary, the effects of kCer on cell migration and cell differentiation are regulated by cascade crosstalk between downstream Nrp1 and histamine-GPCR pathways in HaCaT cells.
- Published
- 2022
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25. Comprehensive Glycomic Approach Reveals Novel Low-Molecular-Weight Blood Group-Specific Glycans in Serum and Cerebrospinal Fluid.
- Author
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Furukawa JI, Hanamatsu H, Yokota I, Hirayama M, Ando T, Kobayashi H, Ohnishi S, Miura N, Okada K, Sakai S, Yuyama K, Igarashi Y, Ito M, Shinohara Y, and Sakamoto N
- Subjects
- Glycoproteins, Humans, Oligosaccharides, Polysaccharides, Blood Group Antigens, Glycomics
- Abstract
ABO blood antigens on the human red blood cell membrane as well as different cells in various human tissues have been thoroughly studied. Anti-A and -B antibodies of IgM are present in serum/plasma, but blood group-specific glyco-antigens have not been extensively described. In this study, we performed comprehensive and quantitative serum glycomic analyses of various glycoconjugates and free oligosaccharides in all blood groups. Our comprehensive glycomic approach revealed that blood group-specific antigens in serum/plasma are predominantly present on glycosphingolipids on lipoproteins rather than glycoproteins. Expression of the ABO antigens on glycosphingolipids depends not only on blood type but also on secretor status. Blood group-specific glycans in serum/plasma were classified as type I, whereas those on RBCs had different structures including hexose and hexosamine residues. Analysis of free oligosaccharides revealed that low-molecular-weight blood group-specific glycans, commonly containing lacto- N -difucotetraose, were expressed in serum/plasma according to blood group. Furthermore, comprehensive glycomic analysis in human cerebrospinal fluid showed that many kinds of free oligosaccharides were highly expressed, and low-molecular-weight blood group-specific glycans, which existed in plasma from the same individuals, were present. Our findings provide the first evidence for low-molecular-weight blood group-specific glycans in both serum/plasma and cerebrospinal fluid.
- Published
- 2021
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26. Structure-dependent absorption of atypical sphingoid long-chain bases from digestive tract into lymph.
- Author
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Mikami D, Sakai S, Nishimukai M, Yuyama K, Mukai K, and Igarashi Y
- Subjects
- Animals, Ceramides chemistry, Ceramides metabolism, Chromatography, Liquid, Dietary Supplements, Gastrointestinal Tract drug effects, Humans, Lymph drug effects, Pleurotus genetics, Rats, Sphingolipids chemistry, Sphingolipids genetics, Sphingomyelins chemistry, Tandem Mass Spectrometry, Gastrointestinal Tract metabolism, Lymph metabolism, Sphingolipids metabolism, Sphingomyelins metabolism
- Abstract
Background: Dietary sphingolipids have various biofunctions, including skin barrier improvement and anti-inflammatory and anti-carcinoma properties. Long-chain bases (LCBs), the essential backbones of sphingolipids, are expected to be important for these bioactivities, and they vary structurally between species. Given these findings, however, the absorption dynamics of each LCB remain unclear., Methods: In this study, five structurally different LCBs were prepared from glucosylceramides (GlcCers) with LCB 18:2(4E,8Z);2OH and LCB 18:2(4E,8E);2OH moieties derived from konjac tuber (Amorphophallus konjac), from GlcCers with an LCB 18(9Me):2(4E,8E);2OH moiety derived from Tamogi mushroom (Pleurotus cornucopiae var. citrinopileatus), and from ceramide 2-aminoethyphosphonate with LCB 18:3(4E,8E,10E);2OH moiety and LCB 18(9Me):3(4E,8E,10E);2OH moiety derived from giant scallop (Mizuhopecten yessoensis), and their absorption percentages and metabolite levels were analyzed using a lymph-duct-cannulated rat model via liquid chromatography tandem mass spectrometry (LC/MS/MS) with a multistage fragmentation method., Results: The five orally administered LCBs were absorbed and detected in chyle (lipid-containing lymph) as LCBs and several metabolites including ceramides, hexosylceramides, and sphingomyelins. The absorption percentages of LCBs were 0.10-1.17%, depending on their structure. The absorption percentage of LCB 18:2(4E,8Z);2OH was the highest (1.17%), whereas that of LCB 18:3(4E,8E,10E);2OH was the lowest (0.10%). The amount of sphingomyelin with an LCB 18:2(4E,8Z);2OH moiety in chyle was particularly higher than sphingomyelins with other LCB moieties., Conclusions: Structural differences among LCBs, particularly geometric isomerism at the C8-C9 position, significantly affected the absorption percentages and ratio of metabolites. This is the first report to elucidate that the absorption and metabolism of sphingolipids are dependent on their LCB structure. These results could be used to develop functional foods that are more readily absorbed.
- Published
- 2021
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27. Mevalonate Pathway-mediated ER Homeostasis Is Required for Haploid Stability in Human Somatic Cells.
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Yaguchi K, Sato K, Yoshizawa K, Mikami D, Yuyama K, Igarashi Y, Banhegyi G, Margittai E, and Uehara R
- Subjects
- Humans, Cholesterol metabolism, Quinolines pharmacology, Mevalonic Acid metabolism, Haploidy, Homeostasis drug effects, Endoplasmic Reticulum metabolism, Endoplasmic Reticulum drug effects, Endoplasmic Reticulum Stress drug effects
- Abstract
The somatic haploidy is unstable in diplontic animals, but cellular processes determining haploid stability remain elusive. Here, we found that inhibition of mevalonate pathway by pitavastatin, a widely used cholesterol-lowering drug, drastically destabilized the haploid state in HAP1 cells. Interestingly, cholesterol supplementation did not restore haploid stability in pitavastatin-treated cells, and cholesterol inhibitor U18666A did not phenocopy haploid destabilization. These results ruled out the involvement of cholesterol in haploid stability. Besides cholesterol perturbation, pitavastatin induced endoplasmic reticulum (ER) stress, the suppression of which by a chemical chaperon significantly restored haploid stability in pitavastatin-treated cells. Our data demonstrate the involvement of the mevalonate pathway in the stability of the haploid state in human somatic cells through managing ER stress, highlighting a novel link between ploidy and ER homeostatic control.Key words: haploid, ER stress, Mevalonate pathway.
- Published
- 2021
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28. Lysosomal-associated transmembrane protein 4B regulates ceramide-induced exosome release.
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Yuyama K, Sun H, Mikami D, Mioka T, Mukai K, and Igarashi Y
- Subjects
- Amyloid beta-Peptides metabolism, Biological Transport physiology, Cell Line, Tumor, Cell Membrane metabolism, Endocytosis physiology, Humans, Neurons metabolism, Ceramides metabolism, Exosomes metabolism, Lysosomes metabolism, Membrane Proteins metabolism, Oncogene Proteins metabolism
- Abstract
Exosomes are extracellular vesicles that mediate the transport of intracellular molecules, including neurodegenerative agents. Exogenously administrated ceramides have been implicated in the acceleration of exosome production by neurons; however, the molecular machinery involved in this process is unknown. Here, we found that ceramides, especially those consisting of long fatty acids, were internalized into the endocytic pathway in neuroblastoma SH-SY5Y cells to induce exosome secretion through lysosome-associated protein transmembrane 4B (LAPTM4B). Knockdown of LAPTM4B inhibited the ceramide-mediated increase in exosome release completely. Fluorescence microscopy observations indicated that exogenous ceramides promote the transport of multivesicular bodies to the plasma membranes in a LAPTM4B-dependent manner. Similarly, inhibition of acid ceramidase, which tends to induce intracellular ceramide accumulation, increased exosome production by SH-SY5Y cells in a LAPTM4B-dependent manner. Furthermore, the level of amyloid-ß protein (Aß) was decreased in neuronal cells following treatment with exogenous ceramide or inhibition of acid ceramidase, and this effect was attributed to the LAPTM4B-dependent efflux of Aß-containing exosomes. Overall, these findings reveal the novel machinery involved in exosome secretion regulated by ceramides and LAPTM4B, and may contribute to efforts to ameliorate the cellular accumulation of neurodegenerative agents such as Aß., (© 2020 Federation of American Societies for Experimental Biology.)
- Published
- 2020
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29. Blood-brain barrier permeability analysis of plant ceramides.
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Eguchi K, Mikami D, Sun H, Tsumita T, Takahashi K, Mukai K, Yuyama K, and Igarashi Y
- Subjects
- Animals, Blood-Brain Barrier metabolism, Cells, Cultured, Mice, Mice, Inbred BALB C, Sphingomyelins metabolism, Blood-Brain Barrier drug effects, Capillary Permeability, Ceramides pharmacology, Ethanolamines pharmacology
- Abstract
Ceramides, a type of sphingolipid, are cell membrane components and lipid mediators that modulate a variety of cell functions. In plants, ceramides are mostly present in a glucosylated glucosylceramide (GlcCer) form. We previously showed that oral administration of konjac-derived GlcCer to a mouse model of Alzheimer's disease reduced brain amyloid-β and amyloid plaques. Dietary plant GlcCer compounds are absorbed as ceramides, but it is unclear whether they can cross the blood-brain barrier (BBB). Herein, we evaluated the BBB permeability of synthetic plant-type ceramides (4, 8-sphingadienine, d18:2) using mouse and BBB cell culture models, and found that they could permeate the BBB both in vivo and in vitro. In addition, administrated ceramides were partially metabolized to other sphingolipid species, namely sphingomyelin (SM) and GlcCer, while crossing the BBB. Thus, plant ceramides can cross the BBB, suggesting that ceramides and their metabolites might affect brain functions., Competing Interests: KE, KT, KM are employed by Daicel Corporation. This study was funded by Daicel Corporation. This does not affect the authors' adherence to PLOS ONE policies on sharing data and materials.
- Published
- 2020
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30. Glucocerebrosidases catalyze a transgalactosylation reaction that yields a newly-identified brain sterol metabolite, galactosylated cholesterol.
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Akiyama H, Ide M, Nagatsuka Y, Sayano T, Nakanishi E, Uemura N, Yuyama K, Yamaguchi Y, Kamiguchi H, Takahashi R, Aerts JMFG, Greimel P, and Hirabayashi Y
- Subjects
- Animals, Brain cytology, Cell Line, Tumor, Cells, Cultured, Cholesterol metabolism, Female, Galactose metabolism, Galactosylceramides metabolism, Glucosylceramidase genetics, Humans, Male, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Inbred ICR, Myelin Sheath metabolism, Neuroglia metabolism, Neurons metabolism, Oryzias, Rats, Rats, Wistar, Brain metabolism, Cholesterol analogs & derivatives, Glucosylceramidase metabolism
- Abstract
β-Glucocerebrosidase (GBA) hydrolyzes glucosylceramide (GlcCer) to generate ceramide. Previously, we demonstrated that lysosomal GBA1 and nonlysosomal GBA2 possess not only GlcCer hydrolase activity, but also transglucosylation activity to transfer the glucose residue from GlcCer to cholesterol to form β-cholesterylglucoside (β-GlcChol) in vitro β-GlcChol is a member of sterylglycosides present in diverse species. How GBA1 and GBA2 mediate β-GlcChol metabolism in the brain is unknown. Here, we purified and characterized sterylglycosides from rodent and fish brains. Although glucose is thought to be the sole carbohydrate component of sterylglycosides in vertebrates, structural analysis of rat brain sterylglycosides revealed the presence of galactosylated cholesterol (β-GalChol), in addition to β-GlcChol. Analyses of brain tissues from GBA2-deficient mice and GBA1- and/or GBA2-deficient Japanese rice fish ( Oryzias latipes ) revealed that GBA1 and GBA2 are responsible for β-GlcChol degradation and formation, respectively, and that both GBA1 and GBA2 are responsible for β-GalChol formation. Liquid chromatography-tandem MS revealed that β-GlcChol and β-GalChol are present throughout development from embryo to adult in the mouse brain. We found that β-GalChol expression depends on galactosylceramide (GalCer), and developmental onset of β-GalChol biosynthesis appeared to be during myelination. We also found that β-GlcChol and β-GalChol are secreted from neurons and glial cells in association with exosomes. In vitro enzyme assays confirmed that GBA1 and GBA2 have transgalactosylation activity to transfer the galactose residue from GalCer to cholesterol to form β-GalChol. This is the first report of the existence of β-GalChol in vertebrates and how β-GlcChol and β-GalChol are formed in the brain., (© 2020 Akiyama et al.)
- Published
- 2020
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31. Nrp1 is Activated by Konjac Ceramide Binding-Induced Structural Rigidification of the a1a2 Domain.
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Usuki S, Yasutake Y, Tamura N, Tamura T, Tanji K, Saitoh T, Murai Y, Mikami D, Yuyama K, Monde K, Mukai K, and Igarashi Y
- Subjects
- Binding Sites, Cell Line, Tumor, Glucosylceramides chemistry, Humans, Immunoprecipitation, Models, Molecular, Neuropilin-1 chemistry, Protein Domains, Semaphorin-3A metabolism, Glucosylceramides pharmacology, Neuropilin-1 metabolism
- Abstract
Konjac ceramide (kCer) is a plant-type ceramide composed of various long-chain bases and a-hydroxyl fatty acids. The presence of d4t,8t-sphingadienine is essential for semaphorin 3A (Sema3A)-like activity. Herein, we examined the three neuropilin 1 (Nrp1) domains (a1a2, b1b2, or c), and found that a1a2 binds to d4t,8t-kCer and possesses Sema3A-like activity. kCer binds to Nrp1 with a weak affinity of mM dissociation constant (Kd). We wondered whether bovine serum albumin could influence the ligand-receptor interaction that a1a2 has with a single high affinity binding site for kCer (Kd in nM range). In the present study we demonstrated the influence of bovine serum albumin. Thermal denaturation indicates that the a1a2 domain may include intrinsically disordered region (IDR)-like flexibility. A potential interaction site on the a1 module was explored by molecular docking, which revealed a possible Nrp1 activation mechanism, in which kCer binds to Site A close to the Sema3A-binding region of the a1a2 domain. The a1 module then accesses a2 as the IDR-like flexibility becomes ordered via kCer-induced protein rigidity of a1a2. This induces intramolecular interaction between a1 and a2 through a slight change in protein secondary structure.
- Published
- 2020
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32. Study of the pharmacokinetics of eriodictyol-6-C-β-d-glucoside, a flavonoid of rooibos (Aspalathus linearis) extract, after its oral administration in mice.
- Author
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Yuyama K, Nakamura Y, Tateyama R, Arakaki R, Tsutsui T, and Ishimaru N
- Subjects
- Administration, Oral, Animals, Flavanones chemistry, Glucosides chemistry, Limit of Detection, Linear Models, Male, Mice, Mice, Inbred C57BL, Plant Extracts administration & dosage, Plant Extracts chemistry, Reproducibility of Results, Salivary Glands chemistry, Skin chemistry, Tissue Distribution, Aspalathus chemistry, Flavanones analysis, Flavanones pharmacokinetics, Glucosides analysis, Glucosides pharmacokinetics
- Abstract
Systemic dry syndrome affects quality of life, and various effective methods are being developed for its treatment. We recently found that rooibos (Aspalathus linearis) extract activates muscarinic M
3 receptor and improves dryness in mice and humans. We identified eriodictyol-6-C-β-D -glucoside (E6CG) as the active component affecting the secretory functions of exocrine glands; however, the pharmacokinetics and distribution of E6CG in exocrine glands have not been elucidated in mice receiving rooibos extract. We have developed a quantification method using LC-MS/MS to detect E6CG without an internal standard. Experiments on C57BL/6 mice administered rooibos extract showed that E6CG was transferred into blood plasma, with its concentration levels peaking 19.3 min after treatment. Substantial levels of E6CG were detected in the submandibular, sublingual, parotid, and lacrimal glands and in the sweat glands in palm skin. This study reports that rooibos extracts containing E6CG can be used as functional foods for improving systemic dryness., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2020
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33. Plant sphingolipids promote extracellular vesicle release and alleviate amyloid-β pathologies in a mouse model of Alzheimer's disease.
- Author
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Yuyama K, Takahashi K, Usuki S, Mikami D, Sun H, Hanamatsu H, Furukawa J, Mukai K, and Igarashi Y
- Subjects
- Administration, Oral, Alzheimer Disease genetics, Alzheimer Disease psychology, Amyloid beta-Peptides metabolism, Animals, Brain cytology, CD56 Antigen metabolism, Disease Models, Animal, Glucosylceramides chemistry, Glucosylceramides pharmacology, Maze Learning drug effects, Mice, Mice, Transgenic, Neural Cell Adhesion Molecule L1 metabolism, Plant Extracts chemistry, Alzheimer Disease drug therapy, Amorphophallus chemistry, Amyloid beta-Peptides genetics, Extracellular Vesicles metabolism, Glucosylceramides adverse effects
- Abstract
The accumulation of amyloid-β protein (Aβ) in brain is linked to the early pathogenesis of Alzheimer's disease (AD). We previously reported that neuron-derived exosomes promote Aβ clearance in the brains of amyloid precursor protein transgenic mice and that exosome production is modulated by ceramide metabolism. Here, we demonstrate that plant ceramides derived from Amorphophallus konjac, as well as animal-derived ceramides, enhanced production of extracellular vesicles (EVs) in neuronal cultures. Oral administration of plant glucosylceramide (GlcCer) to APP overexpressing mice markedly reduced Aβ levels and plaque burdens and improved cognition in a Y-maze learning task. Moreover, there were substantial increases in the neuronal marker NCAM-1, L1CAM, and Aβ in EVs isolated from serum and brain tissues of the GlcCer-treated AD model mice. Our data showing that plant ceramides prevent Aβ accumulation by promoting EVs-dependent Aβ clearance in vitro and in vivo provide evidence for a protective role of plant ceramides in AD. Plant ceramides might thus be used as functional food materials to ameliorate AD pathology.
- Published
- 2019
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34. Novel effects of rooibos extract on tear and saliva secretion mediated by the muscarinic acetylcholine receptor 3 in mice.
- Author
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Arakaki R, Ushio A, Kisoda S, Sato M, Nakamura Y, Yuyama K, Tateyama R, Morishita S, Monoi N, Kudo Y, and Ishimaru N
- Subjects
- Animals, Humans, Mice, Mice, Inbred C57BL, Plant Extracts, Quality of Life, Receptors, Muscarinic, Saliva, South Africa, Aspalathus
- Abstract
Objectives: Sicca syndrome is characterized by dry mouth and eyes and results in a reduction of the patient's quality of life. Various natural plants, including certain herbs, have long been employed to alleviate such symptoms. Rooibos grown in South Africa is one of the potent herbal plants used for the treating dry mouth. However, the precise mechanism of action by which rooibos alleviates symptoms of dryness remains unclear., Methods: The in vivo effects of rooibos extract (RE), which comprises eriodictyol-6-C-glucoside, on the secretory function of saliva and tears were analyzed after intraoral RE administration using wild-type C57BL/6 (B6) mice. In addition, the mechanisms of RE were investigated after administration of a muscarinic acetylcholine receptor 3 (M3R) antagonist., Results: Tear and saliva volumes in mice increased significantly and in a dose-dependent manner following intraoral RE administration compared to those in mice in the control group administered H
2 O. An experiment performed using darifenacin administration revealed that the effects of RE on secretory function were exerted via M3R., Conclusion: These results suggest that RE administration is an effective treatment for symptoms of dryness and may be used in clinical settings against sicca syndrome., (Copyright © 2019. Published by Elsevier B.V.)- Published
- 2019
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35. Malabaricone C as Natural Sphingomyelin Synthase Inhibitor against Diet-Induced Obesity and Its Lipid Metabolism in Mice.
- Author
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Othman MA, Yuyama K, Murai Y, Igarashi Y, Mikami D, Sivasothy Y, Awang K, and Monde K
- Abstract
The interaction between natural occurring inhibitors and targeted membrane proteins could be an alternative medicinal strategy for the treatment of metabolic syndrome, notably, obesity. In this study, we identified malabaricones A-C and E ( 1 - 4 ) isolated from the fruits of Myristica cinnamomea King as natural inhibitors for sphingomyelin synthase (SMS), a membrane protein responsible for sphingolipid biosynthesis. Having the most promising inhibition, oral administration of compound 3 exhibited multiple efficacies in reducing weight gain, improving glucose tolerance, and reducing hepatic steatosis in high fat diet-induced obesity mice models. Liver lipid analysis revealed a crucial link between the SMS activities of compound 3 and its lipid metabolism in vitro and in vivo . The nontoxic nature of compound 3 makes it a suitable candidate in search of drugs which can be employed in the treatment and prevention of obesity., Competing Interests: The authors declare no competing financial interest.
- Published
- 2019
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36. Isolation of Sphingoid Bases from Starfish Asterias amurensis Glucosylceramides and Their Effects on Sphingolipid Production in Cultured Keratinocytes.
- Author
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Mikami D, Sakai S, Yuyama K, and Igarashi Y
- Subjects
- Animals, Cells, Cultured, Ceramides metabolism, Chromatography, High Pressure Liquid, Glucosylceramides metabolism, Humans, Ligands, PPAR gamma, Sphingolipids analysis, Structure-Activity Relationship, Glucosylceramides chemistry, Keratinocytes metabolism, Sphingolipids metabolism, Starfish chemistry
- Abstract
Starfish Asterias amurensis produces sphingoid bases d18:3, 9-methyl-d18:3 (9Me-d18:3), and d22:2, which possess unique structural features. In this study, sphingoid bases prepared from A. amurensis glucosylceramides displayed unexpected elution behaviors from a general octadecyl silyl high-performance liquid chromatography (HPLC) column. For separation and isolation, sphingoid bases were fractionated by octadecyl silyl HPLC after N-acetylation, yielding d18:3, 9Me-d18:3, and two d22:2 isomers. To compare the biological activities of individual sphingoid bases, their effects on sphingolipid production in normal human keratinocytes were evaluated. Treatment with sphingoid bases increased the content of ceramides, glucosylceramides, and sphingomyelins in keratinocytes. Moreover, ceramides, which contain saturated ultra-long-chain fatty acids (C30-34), were significantly increased by treatment with d18:3, but not with other A. amurensis sphingoid bases. The mRNA level of the early differentiation marker keratin 10 was markedly decreased and sphingolipid synthesis-related genes were slightly increased in keratinocytes exposed to A. amurensis-derived d18:3, 9Me-d18:3, and d22:2 isomers. These results suggest that A. amurensis-derived sphingoid bases induce differentiation to varying degrees, sphingolipid production depends on their chemical structures, and d18:3 is the most promising functional sphingoid base.
- Published
- 2019
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37. Extracellular Vesicles from Amnion-Derived Mesenchymal Stem Cells Ameliorate Hepatic Inflammation and Fibrosis in Rats.
- Author
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Ohara M, Ohnishi S, Hosono H, Yamamoto K, Yuyama K, Nakamura H, Fu Q, Maehara O, Suda G, and Sakamoto N
- Abstract
Background: There are no approved drug treatments for liver fibrosis and nonalcoholic steatohepatitis (NASH), an advanced stage of fibrosis which has rapidly become a major cause of cirrhosis. Therefore, development of anti-inflammatory and antifibrotic therapies is desired. Mesenchymal stem cell- (MSC-) based therapy, which has been extensively investigated in regenerative medicine for various organs, can reportedly achieve therapeutic effect in NASH via paracrine action. Extracellular vesicles (EVs) encompass a variety of vesicles released by cells that fulfill functions similar to those of MSCs. We herein investigated the therapeutic effects of EVs from amnion-derived MSCs (AMSCs) in rats with NASH and liver fibrosis., Methods: NASH was induced by a 4-week high-fat diet (HFD), and liver fibrosis was induced by intraperitoneal injection of 2 mL/kg 50% carbon tetrachloride (CCl
4 ) twice a week for six weeks. AMSC-EVs were intravenously injected at weeks 3 and 4 in rats with NASH (15 μ g/kg) and at week 3 in rats with liver fibrosis (20 μ g/kg). The extent of inflammation and fibrosis was evaluated with quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The effect of AMSC-EVs on inflammatory and fibrogenic response was investigated in vitro ., Results: AMSC-EVs significantly decreased the number of Kupffer cells (KCs) in the liver of rats with NASH and the mRNA expression levels of inflammatory cytokines such as tumor necrosis factor- ( Tnf- ) α , interleukin- ( Il- ) 1β and Il-6 , and transforming growth factor- ( Tgf- ) β . Furthermore, AMSC-EVs significantly decreased fiber accumulation, KC number, and hepatic stellate cell (HSC) activation in rats with liver fibrosis. In vitro , AMSC-EVs significantly inhibited KC and HSC activation and suppressed the lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4) signaling pathway., Conclusions: AMSC-EVs ameliorated inflammation and fibrogenesis in a rat model of NASH and liver fibrosis, potentially by attenuating HSC and KC activation. AMSC-EV administration should be considered as a new therapeutic strategy for chronic liver disease.- Published
- 2018
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38. Konjac Ceramide (kCer) Regulates NGF-Induced Neurite Outgrowth via the Sema3A Signaling Pathway.
- Author
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Usuki S, Tamura N, Yuyama K, Tamura T, Mukai K, and Igarashi Y
- Subjects
- Amorphophallus, Animals, Antibodies pharmacology, Carbazoles pharmacology, Cell Line, Tumor, Indole Alkaloids pharmacology, Intercellular Signaling Peptides and Proteins, Mice, Microtubules drug effects, Microtubules ultrastructure, Nerve Growth Factor pharmacology, Nerve Tissue Proteins metabolism, Neuropilin-1 immunology, Phosphorylation drug effects, Rats, Semaphorin-3A metabolism, Glucosylceramides pharmacology, Neuronal Outgrowth drug effects, Semaphorin-3A agonists, Signal Transduction drug effects
- Abstract
The tuber of the konjac plant is a source enriched with GlcCer (kGlcCer), and has been used as a dietary supplement to improve the dry skin and itching that are caused by a deficiency of epidermal ceramide. Previously, we showed chemoenzymatically prepared konjac ceramide has a neurite-outgrowth inhibitory effect that is very similar to that of Sema3A and is not seen with animal-type ceramides. While, it has been unclear whether kCer may act on Sema3A or TrkA signaling pathway. In the present study, we showed kCer induces phosphorylation of CRMP2 and microtubules depolymerization via Sema3A signaling pathway not TrkA. It is concluded that kCer may be a potential Sema3A-like agonist that activates Sema3A signaling pathway directly.
- Published
- 2018
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39. Direct Involvement of Arachidonic Acid in the Development of Ear Edema via TRPV3.
- Author
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Sanaki T, Kasai-Yamamoto E, Yoshioka T, Sakai S, Yuyama K, Fujiwara T, Numata Y, and Igarashi Y
- Subjects
- Animals, Arachidonic Acids metabolism, Female, Lipoxygenase physiology, Male, Mice, Inbred C57BL, Mice, Inbred ICR, Prostaglandin-Endoperoxide Synthases physiology, TRPV Cation Channels metabolism, Arachidonic Acids adverse effects, Arachidonic Acids physiology, Ear Diseases etiology, Edema etiology, TRPV Cation Channels physiology
- Abstract
Arachidonic acid (AA) plays a pivotal role in the development of edema via its oxidized metabolites derived from cyclooxygenase (COX) and lipoxygenase (LOX), and is recently recognized as an activator of TRPV3. However, it is not clear whether AA plays some TRPV3-mediated pathological roles in the development of edema. Pharmacological and histological studies using ICR
TRPV3+/+ and ICRTRPV3-/- mice indicated that higher ear edema responses to topical application of AA were observed in ICRTRPV3+/+ mice compared with ICRTRPV3-/- mice. However, there was no difference in the ear edema response to 12-O-tetradecanoylphorbol 13-acetate, skin histology, and skin barrier function between these mouse strains. Furthermore, oxidized fatty acids from the lesional site were analyzed to elucidate the TRPV3-mediated pathological roles of AA, and the results revealed that there were no differences in the level of COX or LOX metabolites derived from AA between both mouse strains. We concluded that AA plays a role in the development of TRPV3-mediated ear edema and that this result may contribute to better understanding of the pathophysiological mechanisms involved in the development of a certain type of edema.- Published
- 2017
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40. Exosomes as Carriers of Alzheimer's Amyloid-ß.
- Author
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Yuyama K and Igarashi Y
- Abstract
The intracerebral level of the aggregation-prone peptide, amyloid-ß (Aß), is constantly maintained by multiple clearance mechanisms, including several degradation enzymes, and brain efflux. Disruption of the clearance machinery and the resultant Aß accumulation gives rise to neurotoxic assemblies, leading to the pathogenesis of Alzheimer's disease (AD). In addition to the classic mechanisms of Aß clearance, the protein may be processed by secreted vesicles, although this possibility has not been extensively investigated. We showed that neuronal exosomes, a subtype of extracellular nanovesicles, enwrap, or trap Aß and transport it into microglia for degradation. Here, we review Aß sequestration and elimination by exosomes, and discuss how this clearance machinery might contribute to AD pathogenesis and how it might be exploited for effective AD therapy.
- Published
- 2017
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41. Optical Trapping-Formed Colloidal Assembly with Horns Extended to the Outside of a Focus through Light Propagation.
- Author
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Kudo T, Wang SF, Yuyama K, and Masuhara H
- Abstract
We report optical trapping and assembling of colloidal particles at a glass/solution interface with a tightly focused laser beam of high intensity. It is generally believed that the particles are gathered only in an irradiated area where optical force is exerted on the particles by laser beam. Here we demonstrate that, the propagation of trapping laser from the focus to the outside of the formed assembly leads to expansion of the assembly much larger than the irradiated area with sticking out rows of linearly aligned particles like horns. The shape of the assembly, its structure, and the number of horns can be controlled by laser polarization. Optical trapping study utilizing the light propagation will open a new avenue for assembling and crystallizing quantum dots, metal nanoparticles, molecular clusters, proteins, and DNA.
- Published
- 2016
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42. A potential function for neuronal exosomes: sequestering intracerebral amyloid-β peptide.
- Author
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Yuyama K, Sun H, Usuki S, Sakai S, Hanamatsu H, Mioka T, Kimura N, Okada M, Tahara H, Furukawa J, Fujitani N, Shinohara Y, and Igarashi Y
- Subjects
- Alzheimer Disease genetics, Alzheimer Disease pathology, Amyloid beta-Peptides genetics, Animals, Exosomes genetics, Exosomes pathology, Humans, Macaca fascicularis, Mice, Mice, Transgenic, Neuroglia metabolism, Neuroglia pathology, Neurons pathology, Alzheimer Disease cerebrospinal fluid, Amyloid beta-Peptides cerebrospinal fluid, Exosomes metabolism, Neurons metabolism
- Abstract
Elevated amyloid-β peptide (Aβ) in brain contributes to Alzheimer's disease (AD) pathogenesis. We demonstrated the presence of exosome-associated Aβ in the cerebrospinal fluid (CSF) of cynomolgus monkeys and APP transgenic mice. The levels of exosome-associated Aβ notably decreased in the CSF of aging animals. We also determined that neuronal exosomes, but not glial exosomes, had abundant glycosphingolipids and could capture Aβ. Infusion of neuronal exosomes into brains of APP transgenic mice decreased Aβ and amyloid depositions, similarly to what reported previously on neuroblastoma-derived exosomes. These findings highlight the role of neuronal exosomes in Aβ clearance, and suggest that their downregulation might relate to Aβ accumulation and, ultimately, the development of AD pathology., (Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)
- Published
- 2015
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43. Altered levels of serum sphingomyelin and ceramide containing distinct acyl chains in young obese adults.
- Author
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Hanamatsu H, Ohnishi S, Sakai S, Yuyama K, Mitsutake S, Takeda H, Hashino S, and Igarashi Y
- Abstract
Objective: Recent studies indicate that sphingolipids, sphingomyelin (SM) and ceramide (Cer) are associated with the development of metabolic syndrome. However, detailed profiles of serum sphingolipids in the pathogenesis of this syndrome are lacking. Here we have investigated the relationship between the molecular species of sphingolipids in serum and the clinical features of metabolic syndrome, such as obesity, insulin resistance, fatty liver disease and atherogenic dyslipidemia., Subjects: We collected serum from obese (body mass index, BMI⩾35, n=12) and control (BMI=20-22, n=11) volunteers (18-27 years old), measured the levels of molecular species of SM and Cer in the serum by liquid chromatography-mass spectrometry and analyzed the parameters for insulin resistance, liver function and lipid metabolism by biochemical blood test., Results: The SM C18:0 and C24:0 levels were higher, and the C20:0 and C22:0 levels tended to be higher in the obese group than in the control group. SM C18:0, C20:0, C22:0 and C24:0 significantly correlated with the parameters for obesity, insulin resistance, liver function and lipid metabolism, respectively. In addition, some Cer species tended to correlate with these parameters. However, SM species containing unsaturated acyl chains and most of the Cer species were not associated with these parameters., Conclusions: The present results demonstrate that the high levels of serum SM species with distinct saturated acyl chains (C18:0, C20:0, C22:0 and C24:0) closely correlate with the parameters of obesity, insulin resistance, liver function and lipid metabolism, suggesting that these SM species are associated with the development of metabolic syndrome and serve as novel biomarkers of metabolic syndrome and its associated diseases.
- Published
- 2014
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- View/download PDF
44. Decreased amyloid-β pathologies by intracerebral loading of glycosphingolipid-enriched exosomes in Alzheimer model mice.
- Author
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Yuyama K, Sun H, Sakai S, Mitsutake S, Okada M, Tahara H, Furukawa J, Fujitani N, Shinohara Y, and Igarashi Y
- Subjects
- Animals, Cell Line, Tumor, Mice, Mice, Inbred C57BL, Microglia metabolism, Amyloid beta-Peptides metabolism, Brain metabolism, Exosomes metabolism, Glycosphingolipids metabolism
- Abstract
Elevated levels of amyloid-β peptide (Aβ) in the human brain are linked to the pathogenesis of Alzheimer disease. Recent in vitro studies have demonstrated that extracellular Aβ can bind to exosomes, which are cell-secreted nanovesicles with lipid membranes that are known to transport their cargos intercellularly. Such findings suggest that the exosomes are involved in Aβ metabolism in brain. Here, we found that neuroblastoma-derived exosomes exogenously injected into mouse brains trapped Aβ and with the associated Aβ were internalized into brain-resident phagocyte microglia. Accordingly, continuous intracerebral administration of the exosomes into amyloid-β precursor protein transgenic mice resulted in marked reductions in Aβ levels, amyloid depositions, and Aβ-mediated synaptotoxicity in the hippocampus. In addition, we determined that glycosphingolipids (GSLs), a group of membrane glycolipids, are highly abundant in the exosomes, and the enriched glycans of the GSLs are essential for Aβ binding and assembly on the exosomes both in vitro and in vivo. Our data demonstrate that intracerebrally administered exosomes can act as potent scavengers for Aβ by carrying it on the exosome surface GSLs and suggest a role of exosomes in Aβ clearance in the central nervous system. Improving Aβ clearance by exosome administration would provide a novel therapeutic intervention for Alzheimer disease., (© 2014 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Published
- 2014
- Full Text
- View/download PDF
45. Pathological roles of ceramide and its metabolites in metabolic syndrome and Alzheimer's disease.
- Author
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Yuyama K, Mitsutake S, and Igarashi Y
- Subjects
- Humans, Alzheimer Disease metabolism, Alzheimer Disease pathology, Ceramides metabolism, Metabolic Syndrome metabolism, Metabolic Syndrome pathology
- Abstract
The public health burden of metabolic syndrome (MetS), a multiplex risk factor that arises from insulin resistance accompanying abnormal adipose conditions, and Alzheimer's disease (AD), the most common form of dementia, continues to expand. Current available therapies for these disorders are of limited effectiveness. Recent findings have indicated that alternations in sphingolipid metabolism contribute to the development of these pathologies. Sphingolipids are major constituents of the plasma membrane, where they are known to form several types of microdomains, and are potent regulators for a variety of physiological processes. Many groups, including ours, have demonstrated that membrane sphingolipids, especially ceramide and its metabolites such as ceramide 1-phosphate, have roles in arteriosclerosis, obesity, diabetes, and inflammation associated with MetS. Aberrant sphingolipid profiles have been observed in human AD brains, and accumulated evidence has demonstrated that changes in membrane properties induced by defective sphingolipid metabolism impair generation and degradation of amyloid-β peptide (Aβ), a pathogenic agent of AD. In this review, we summarize current knowledge and pathophysiological implications of the roles of SLs in MetS and AD, to provide insight into the SL metabolic pathways as potential targets for therapy of these diseases. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology., (© 2013.)
- Published
- 2014
- Full Text
- View/download PDF
46. Laser trapping-induced crystallization of L-phenylalanine through its high-concentration domain formation.
- Author
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Yuyama K, Wu CS, Sugiyama T, and Masuhara H
- Subjects
- Deuterium Oxide chemistry, Temperature, Crystallization methods, Lasers, Phenylalanine chemistry
- Abstract
We present the laser trapping-induced crystallization of L-phenylalanine through high-concentration domain formation in H2O and D2O solutions which is achieved by focusing a continuous-wave (CW) near-infrared laser beam at the solution surface. Upon laser irradiation into the H2O solution, laser trapping of the liquid-like clusters increases the local concentration, accompanying laser heating, and a single plate-like crystal is eventually prepared at the focal spot. On the other hand, in the D2O solution, a lot of the monohydrate needle-like crystals are observed, not at the focal spot where the concentration is high enough to trigger crystal nucleation, but in the 0.5-1.5 mm range from the focal spot. The dynamics and mechanism of the amazing crystallization behaviour induced by laser trapping are discussed from the viewpoints of the concentration increase due to laser heating depending on solvent, the large high-concentration domain formation by laser trapping of liquid-like clusters, and the orientational disorder of molecules/clusters at the domain edge.
- Published
- 2014
- Full Text
- View/download PDF
47. Laser Trapping and Crystallization Dynamics of l-Phenylalanine at Solution Surface.
- Author
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Yuyama K, Sugiyama T, and Masuhara H
- Abstract
We present laser trapping behavior of l-phenylalanine (l-Phe) at a surface of its unsaturated aqueous solution by a focused continuous-wave (CW) near-infrared (NIR) laser beam. Upon the irradiation into the solution surface, laser trapping of the liquid-like clusters is induced concurrently with local laser heating, forming an anhydrous plate-like crystal at the focal spot. The following laser irradiation into a central part of the plate-like crystal leads to laser trapping at the crystal surface not only for l-Phe molecules/clusters but also for polystyrene (PS) particles. The particles are closely packed at crystal edges despite that the crystal surface is not illuminated by the laser directly. The molecules/clusters are also gathered and adsorbed to the crystal surface, leading to crystal growth. The trapping dynamics and mechanism are discussed in view of optical potential formed at the crystal surface by light propagation inside the crystal.
- Published
- 2013
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48. Cooperative Synthesis of Ultra Long-Chain Fatty Acid and Ceramide during Keratinocyte Differentiation.
- Author
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Mizutani Y, Sun H, Ohno Y, Sassa T, Wakashima T, Obara M, Yuyama K, Kihara A, and Igarashi Y
- Subjects
- Eye Proteins metabolism, Gene Knockdown Techniques, HEK293 Cells, Humans, Immunoblotting, In Situ Hybridization, Membrane Proteins metabolism, PPAR delta genetics, PPAR delta metabolism, PPAR-beta genetics, PPAR-beta metabolism, RNA Interference, RNA, Messenger metabolism, Real-Time Polymerase Chain Reaction, Sphingosine N-Acyltransferase genetics, Sphingosine N-Acyltransferase metabolism, Up-Regulation physiology, Cell Differentiation physiology, Ceramides biosynthesis, Fatty Acids biosynthesis, Keratinocytes metabolism
- Abstract
The lipid lamellae in the stratum corneum is important for the epidermal permeability barrier. The lipid lamellae component ceramide (CER), comprising an ultra long-chain (ULC) fatty acid (FA) of ≥26 carbons (ULC CER), plays an essential role in barrier formation. ULC acyl-CoAs, produced by the FA elongase ELOVL4, are converted to ULC CERs by the CER synthase CERS3. In the presented study, we observed that ELOVL4 and CERS3 mRNAs increased during keratinocyte differentiation in vivo and in vitro. We also determined that peroxisome proliferator-activated receptor β/δ is involved in the up-regulation of the mRNAs. Knockdown of CERS3 caused a reduction in the elongase activities toward ULC acyl-CoAs, suggesting that CERS3 positively regulates ULCFA. Thus, we reveal that the two key players in ULC CER production in epidermis, CERS3 and ELOVL4, are coordinately regulated at both the transcriptional and enzymatic levels.
- Published
- 2013
- Full Text
- View/download PDF
49. Involvement of gangliosides in the process of Cbp/PAG phosphorylation by Lyn in developing cerebellar growth cones.
- Author
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Sekino-Suzuki N, Yuyama K, Miki T, Kaneda M, Suzuki H, Yamamoto N, Yamamoto T, Oneyama C, Okada M, and Kasahara K
- Subjects
- Animals, Animals, Newborn, Antibodies pharmacology, Cells, Cultured, Cricetinae, Gangliosides immunology, Growth Cones drug effects, Growth Cones ultrastructure, Membrane Microdomains metabolism, Microscopy, Immunoelectron, Neurons drug effects, Phosphorylation, Rats, Tyrosine metabolism, Cerebellum cytology, Cerebellum growth & development, Gangliosides metabolism, Growth Cones metabolism, Membrane Proteins metabolism, Neurons cytology, Phosphoproteins metabolism, src-Family Kinases metabolism
- Abstract
The association of gangliosides with specific proteins in the central nervous system was examined by coimmunoprecipitation with an anti-ganglioside antibody. The monoclonal antibody to the ganglioside GD3 (R24) immunoprecipitated the Csk (C-terminal src kinase)-binding protein (Cbp). Sucrose density gradient analysis showed that Cbp of rat cerebellum was detected in detergent-resistant membrane (DRM) raft fractions. R24 treatment of the rat primary cerebellar cultures induced Lyn activation and tyrosine phosphorylation of Cbp. Treatment with anti-ganglioside GD1b antibody also induced tyrosine phosphorylation. Furthermore, over-expressions of Lyn and Cbp in Chinese hamster ovary (CHO) cells resulted in tyrosine 314 phosphorylation of Cbp, which indicates that Cbp is a substrate for Lyn. Immunoblotting analysis showed that the active form of Lyn and the Tyr314-phosphorylated form of Cbp were highly accumulated in the DRM raft fraction prepared from the developing cerebellum compared with the DRM raft fraction of the adult one. In addition, Lyn and the Tyr314-phosphorylated Cbp were highly concentrated in the growth cone fraction prepared from the developing cerebellum. Immunoelectron microscopy showed that Cbp and GAP-43, a growth cone marker, are localized in the same vesicles of the growth cone fraction. These results suggest that Cbp functionally associates with gangliosides on growth cone rafts in developing cerebella., (© 2012 International Society for Neurochemistry.)
- Published
- 2013
- Full Text
- View/download PDF
50. Laser trapping chemistry: from polymer assembly to amino acid crystallization.
- Author
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Sugiyama T, Yuyama K, and Masuhara H
- Subjects
- Glycine chemistry, Solutions chemistry, Amino Acids chemistry, Crystallization, Lasers, Nanoparticles chemistry, Polymers chemistry
- Abstract
Laser trapping has served as a useful tool in physics and biology, but, before our work, chemists had not paid much attention to this technique because molecules are too small to be trapped in solution at room temperature. In late 1980s, we demonstrated laser trapping of micrometer-sized particles, developed various methodologies for their manipulation, ablation, and patterning in solution, and elucidated their dynamics and mechanism. In the 1990s, we started laser trapping studies on polymers, micelles, dendrimers, and gold, as well as polymer nanoparticles. Many groups also reported laser trapping studies of nanoclusters, DNA, colloidal suspensions, etc. Following these research streams, we have explored new molecular phenomena induced by laser trapping. Gradient force leading to trapping, mass transfer by local heating, and molecular reorientation following laser polarization are intimately coupled with molecular cluster and aggregate formation due to their intermolecular interactions, which depend on whether the trapping position is at the interface/surface or in solution. In this Account, we summarize our systematic studies on laser trapping chemistry and present some new advances and our future perspectives. We describe the laser trapping of nanoparticles, polymers, and amino acid clusters in solution by focusing a continuous wave 1064 nm laser beam on the molecules of interest and consider their dynamics and mechanism. In dilute solution, nanoparticles with weak mutual interactions are individually trapped at the focal point, while laser trapping of nanoparticles in concentrated solution assembles and confines numerous particles at the focal spot. The assembly of polymers during their laser trapping extends out from the focal point because of the interpolymer interactions, heat transfer, and solvent flow. When the trapping laser is focused at an interface between a thin heavy water solution film of glycine and a glass substrate, the assembled molecules nucleate and evolve to a liquid-liquid phase separation, or they will crystallize if the trapping laser is focused on the solution surface. Laser trapping can induce spatiotemporally the liquid and solid nucleation of glycine, and the dense liquid droplet or crystal formed can grow to a bulk scale. We can control the polymorph of the formed glycine crystal selectively by tuning trapping laser polarization and power. These results provide a new approach to elucidate dynamics and mechanism of crystallization and are the fundamental basis for studying not only enantioselective crystallization but also confined polymerization, trapping dynamics by ultrashort laser pulses, and resonance effect in laser trapping.
- Published
- 2012
- Full Text
- View/download PDF
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