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Wong KL, Wu YR, Cheng KS, Chan P, Cheung CW, Lu DY, Su TH, Liu ZM, Leung YM. Palmitic acid-induced lipotoxicity and protection by (+)-catechin in rat cortical astrocytes. Pharmacol Rep 2014; 66:1106-13. [PMID: 25443742 DOI: 10.1016/j.pharep.2014.07.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Astrocytes do not only maintain homeostasis of the extracellular milieu of the neurons, but also play an active role in modulating synaptic transmission. Palmitic acid (PA) is a saturated fatty acid which, when being excessive, is a significant risk factor for lipotoxicity. Activation of astrocytes by PA has been shown to cause neuronal inflammation and demyelination. However, direct damage by PA to astrocytes is relatively unexplored. The aim of this study was to identify the mechanism(s) of PA-induced cytotoxicity in rat cortical astrocytes and possible protection by (+)-catechin. METHODS Cytotoxicity and endoplasmic reticulum (ER) markers were assessed by MTT assay and Western blotting, respectively. Cytosolic Ca(2+) and mitochondrial membrane potential (MMP) were measured microfluorimetrically using fura-2 and rhodamine 123, respectively. Intracellular reactive oxygen species (ROS) production was assayed by the indicator 2'-7'-dichlorodihydrofluorescein diacetate. RESULTS Exposure of astrocytes to 100μM PA for 24h resulted in apoptotic cell death. Whilst PA-induced cell death appeared to be unrelated to ER stress and perturbation in cytosolic Ca(2+) signaling, it was likely a result of ROS production and subsequent MMP collapse, since ascorbic acid (anti-oxidant, 100μM) prevented PA-induced MMP collapse and cell death. Co-treatment of astrocytes with (+)-catechin (300μM), an anti-oxidant found abundantly in green tea, significantly prevented PA-induced ROS production, MMP collapse and cell death. CONCLUSION Our results suggest that PA-induced cytotoxicity in astrocytes may involve ROS generation and MMP collapse, which can be prevented by (+)-catechin.
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Affiliation(s)
- Kar-Lok Wong
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan; Department of Anesthesiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong; Department of Anesthesiology, Shandong University Nanshan Branch of Qilu Hospital, China
| | - Yu-Ru Wu
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan
| | - Ka-Shun Cheng
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan
| | - Paul Chan
- Division of Cardiology, Department of Medicine, Taipei Medical University Wan Fan Hospital, Taipei, Taiwan
| | - Chi-Wai Cheung
- Department of Anesthesiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Dah-Yuu Lu
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan
| | - Tzu-Hui Su
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan
| | - Zhong-Min Liu
- Department of Cardiovascular Surgery, Shanghai East Hospital, Tongji University, Shanghai, China.
| | - Yuk-Man Leung
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan.
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Hsieh WT, Chiang BH. A well-refined in vitro model derived from human embryonic stem cell for screening phytochemicals with midbrain dopaminergic differentiation-boosting potential for improving Parkinson's disease. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:6326-6336. [PMID: 24933592 DOI: 10.1021/jf501640a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Stimulation of endogenous neurogenesis is a potential approach to compensate for loss of dopaminergic neurons of substantia nigra compacta nigra (SNpc) in patients with Parkinson's disease (PD). This objective was to establish an in vitro model by differentiating pluripotent human embryonic stem cells (hESCs) into midbrain dopaminergic (mDA) neurons for screening phytochemicals with mDA neurogenesis-boosting potentials. Consequently, a five-stage differentiation process was developed. The derived cells expressed many mDA markers including tyrosine hydroxylase (TH), β-III tubulin, and dopamine transporter (DAT). The voltage-gated ion channels and dopamine release were also examined for verifying neuron function, and the dopamine receptor agonists bromocriptine and 7-hydroxy-2-(dipropylamino)tetralin (7-OH-DPAT) were used to validate our model. Then, several potential phytochemicals including green tea catechins and ginsenosides were tested using the model. Finally, ginsenoside Rb1 was identified as the most potent phytochemical which is capable of upregulating neurotrophin expression and inducing mDA differentiation.
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Affiliation(s)
- Wen-Ting Hsieh
- Institute of Food Science and Technology, National Taiwan University , No. 1, Roosevelt Road, Section 4, Taipei, Taiwan ROC
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Takahashi A, Watanabe T, Fujita T, Hasegawa T, Saito M, Suganuma M. Green tea aroma fraction reduces β-amyloid peptide-induced toxicity in Caenorhabditis elegans transfected with human β-amyloid minigene. Biosci Biotechnol Biochem 2014; 78:1206-11. [DOI: 10.1080/09168451.2014.921553] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Green tea is a popular world-wide beverage with health benefits that include preventive effects on cancer as well as cardiovascular, liver and Alzheimer’s diseases (AD). This study will examine the preventive effects on AD of a unique aroma of Japanese green tea. First, a transgenic Caenorhabditis elegans (C. elegans) CL4176 expressing human β-amyloid peptide (Aβ) was used as a model of AD. A hexane extract of processed green tea was further fractionated into volatile and non-volatile fractions, named roasty aroma and green tea aroma fractions depending on their aroma, by microscale distillation. Both hexane extract and green tea aroma fraction were found to inhibit Aβ-induced paralysis, while only green tea aroma fraction extended lifespan in CL4176. We also found that green tea aroma fraction has antioxidant activity. This paper indicates that the green tea aroma fraction is an additional component for prevention of AD.
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Affiliation(s)
- Atsushi Takahashi
- Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama, Japan
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- Green Tea Laboratory, Saitama Prefectural Agriculture and Forestry Research Center, Saitama, Japan
| | - Tatsuro Watanabe
- Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama, Japan
| | - Takashi Fujita
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Toshio Hasegawa
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Michio Saito
- Green Tea Laboratory, Saitama Prefectural Agriculture and Forestry Research Center, Saitama, Japan
| | - Masami Suganuma
- Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama, Japan
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Lorenz M, Paul F, Moobed M, Baumann G, Zimmermann BF, Stangl K, Stangl V. The activity of catechol-O-methyltransferase (COMT) is not impaired by high doses of epigallocatechin-3-gallate (EGCG) in vivo. Eur J Pharmacol 2014; 740:645-51. [PMID: 24972245 DOI: 10.1016/j.ejphar.2014.06.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 12/22/2022]
Abstract
Catechol-O-methyltransferase (COMT) inactivates many endogenous and exogenous compounds by O-methylation. Therefore, it represents a major enzyme of the metabolic pathway with important biological functions in hormonal and drug metabolism. The tea catechin epigallocatechin-3-gallate (EGCG) is known to inhibit COMT enzymatic activity in vitro. Based on beneficial in vitro results, EGCG is extensively used in human intervention studies in a variety of human diseases. Owing to its low bioavailability, rather high doses of EGCG are frequently applied that may impair COMT activity in vivo. Enzymatic activities of four functional COMT single-nucleotide polymorphisms (SNPs) were determined in red blood cells (RBCs) in 24 healthy human volunteers (14 women, 10 men). The subjects were supplemented with 750 mg of EGCG and EGCG plasma levels and COMT enzyme activities in erythrocytes were measured before and 2 h after intervention. The homozygous Val→Met substitution in the SNP rs4680 resulted in significantly decreased COMT activity. Enzymatic COMT activities in RBCs were also affected by the other three COMT polymorphisms. EGCG plasma levels significantly increased after intervention. They were not influenced by any of the COMT SNPs and different enzyme activities. Ingestion of 750 mg EGCG did not result in impairment of COMT activity. However, COMT activity was significantly increased by 24% after EGCG consumption. These results indicate that supplementation with a high dose of EGCG does not impair the activity of COMT. Consequently, it may not interfere with COMT-mediated metabolism and elimination of exogenous and endogenous COMT substrates.
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Affiliation(s)
- Mario Lorenz
- Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, Charite - Universitätsmedizin Berlin, Schumannstr. 20-21, 10117 Berlin, Germany; DZHK (German Centre for Cardiovascular Research), Berlin, Germany
| | - Friedemann Paul
- NeuroCure Clinical Research Center and Clinical and Experimental Multiple Sclerosis Research Center, Department of Neurology, Charité University Medicine Berlin, Germany
| | - Minoo Moobed
- Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, Charite - Universitätsmedizin Berlin, Schumannstr. 20-21, 10117 Berlin, Germany
| | - Gert Baumann
- Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, Charite - Universitätsmedizin Berlin, Schumannstr. 20-21, 10117 Berlin, Germany
| | - Benno F Zimmermann
- Institute of Nutrition and Food Sciences, University of Bonn, Germany; Institut Prof. Dr. Georg Kurz GmbH, Köln, Germany
| | - Karl Stangl
- Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, Charite - Universitätsmedizin Berlin, Schumannstr. 20-21, 10117 Berlin, Germany
| | - Verena Stangl
- Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, Charite - Universitätsmedizin Berlin, Schumannstr. 20-21, 10117 Berlin, Germany; DZHK (German Centre for Cardiovascular Research), Berlin, Germany.
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Evaluation of plant phenolic metabolites as a source of Alzheimer's drug leads. BIOMED RESEARCH INTERNATIONAL 2014; 2014:843263. [PMID: 24999480 PMCID: PMC4066862 DOI: 10.1155/2014/843263] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/26/2014] [Accepted: 04/28/2014] [Indexed: 01/01/2023]
Abstract
Epidemiological studies have proven an association between consumption of polyphenols and prevention of Alzheimer's disease, the most common form of dementia characterized by extracellular deposition of amyloid beta plaques. The aim of this study is pharmacological screening of the aqueous alcohol extract of Markhamia platycalyx leaves, Schotia brachypetala leaves and stalks, and piceatannol compared to aqueous alcohol extract of Camellia sinensis leaves as potential Alzheimer's disease drugs. LC-HRESI(-ve)-MSn was performed to identify phenolics' profile of Schotia brachypetala stalks aqueous alcohol extract and revealed ten phenolic compounds as first report: daidzein, naringin, procyanidin isomers, procyanidin dimer gallate, quercetin 3-O-rhamnoside, quercetin 3-O-glucuronide, quercetin hexose gallic acid, quercetin hexose protocatechuic acid, and ellagic acid. Alzheimer's disease was induced by a single intraperitoneal injection of LPS. Adult male Swiss albino mice were divided into groups of 8–10 mice each receiving treatment for six days. In vivo behavioral tests (Y maze and object recognition) and in vitro estimation of amyloid beta 42 by ELISA showed significant differences between results of treated and nontreated animals.
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Effect of antioxidants supplementation on aging and longevity. BIOMED RESEARCH INTERNATIONAL 2014; 2014:404680. [PMID: 24783202 PMCID: PMC3982418 DOI: 10.1155/2014/404680] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/11/2014] [Indexed: 01/06/2023]
Abstract
If aging is due to or contributed by free radical reactions, as postulated by the free radical theory of aging, lifespan of organisms should be extended by administration of exogenous antioxidants. This paper reviews data on model organisms concerning the effects of exogenous antioxidants (antioxidant vitamins, lipoic acid, coenzyme Q, melatonin, resveratrol, curcumin, other polyphenols, and synthetic antioxidants including antioxidant nanoparticles) on the lifespan of model organisms. Mechanisms of effects of antioxidants, often due to indirect antioxidant action or to action not related to the antioxidant properties of the compounds administered, are discussed. The legitimacy of antioxidant supplementation in human is considered.
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Giordano S, Darley-Usmar V, Zhang J. Autophagy as an essential cellular antioxidant pathway in neurodegenerative disease. Redox Biol 2013; 2:82-90. [PMID: 24494187 PMCID: PMC3909266 DOI: 10.1016/j.redox.2013.12.013] [Citation(s) in RCA: 266] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 12/15/2013] [Accepted: 12/17/2013] [Indexed: 12/13/2022] Open
Abstract
Oxidative stress including DNA damage, increased lipid and protein oxidation, are important features of aging and neurodegeneration suggesting that endogenous antioxidant protective pathways are inadequate or overwhelmed. Importantly, oxidative protein damage contributes to age-dependent accumulation of dysfunctional mitochondria or protein aggregates. In addition, environmental toxins such as rotenone and paraquat, which are risk factors for the pathogenesis of neurodegenerative diseases, also promote protein oxidation. The obvious approach of supplementing the primary antioxidant systems designed to suppress the initiation of oxidative stress has been tested in animal models and positive results were obtained. However, these findings have not been effectively translated to treating human patients, and clinical trials for antioxidant therapies using radical scavenging molecules such as α-tocopherol, ascorbate and coenzyme Q have met with limited success, highlighting several limitations to this approach. These could include: (1) radical scavenging antioxidants cannot reverse established damage to proteins and organelles; (2) radical scavenging antioxidants are oxidant specific, and can only be effective if the specific mechanism for neurodegeneration involves the reactive species to which they are targeted and (3) since reactive species play an important role in physiological signaling, suppression of endogenous oxidants maybe deleterious. Therefore, alternative approaches that can circumvent these limitations are needed. While not previously considered an antioxidant system we propose that the autophagy-lysosomal activities, may serve this essential function in neurodegenerative diseases by removing damaged or dysfunctional proteins and organelles. Significant oxidative damage occurs in neurodegenerative disease brains. Effective in animal models with single toxins, antioxidants are ineffective in clinical trials. The failure of antioxidant therapy maybe due to propagation of cellular damage. Autophagic clearance of diverse damaged molecules may provide antioxidant mechanisms. Further mechanistic and translational studies on autophagy therapy are needed.
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Key Words
- 6-OHDA, 6-hydroxydopamine
- Animal models
- Anti-oxidants
- Autophagy
- CBZ, carbamazepine
- Clinical trials
- EGCG, epigallocatechin gallate
- GSH, glutathione
- HIF1α, hypoxia-inducible factor 1-alpha
- HNE, 4-hydroxynonenal
- LRRK2, leucine-rich repeat kinase 2
- MDA, malondialdehyde
- MPP+, 1-methyl-4-phenylpyridinium
- MPTP, 1-methyl-4-phenyl-1,2,3,6-tetrahydro pyridine
- MitoQ, mitochondrially-targeted coenzyme Q
- Mitochondrial dysfunction
- MnSOD, manganese superoxide dismutase
- Neurons
- Nrf2, Nuclear factor (erythroid-derived 2)-like 2
- PINK1, PTEN-induced putative kinase 1
- Parkinson’s disease
- Protein aggregation
- ROS/RNS, reactive oxygen and nitrogen species
- Reactive oxygen species
- Redox signaling
- SOD, superoxide dismutase
- Selegiline, N-propargyl-methamphetamine
- Sirt1, NAD-dependent deacetylast sirtuin-1
- TFEB, transcription factor EB
- Toxins
- UCHL1, ubiquitin carboxyl-terminal hydrolase L1
- UPDRS, Unified Parkinson’s Disease Rating Scale
- curcumin, (1E,6E)-1,7-Bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione
- iPSC, induced pluripotent stem cells
- rasagiline, N-propargyl-1-(R)-aminoindan
- the ADAGIO study, the Attenuation of Disease Progression with Azilect Given Once-daily) study
- the DATATOP Study, the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism Study
- the NET-PD network, the NINDS Exploratory Trials in Parkinson’s Disease (NET-PD) network
- the TEMPO Study, the TVP-1012 in Early Monotherapy for PD Outpatients Study
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Affiliation(s)
- Samantha Giordano
- Center for Free Radical Biology, University of Alabama at Birmingham, United States ; Department of Pathology, University of Alabama at Birmingham, United States
| | - Victor Darley-Usmar
- Center for Free Radical Biology, University of Alabama at Birmingham, United States ; Department of Pathology, University of Alabama at Birmingham, United States
| | - Jianhua Zhang
- Center for Free Radical Biology, University of Alabama at Birmingham, United States ; Department of Pathology, University of Alabama at Birmingham, United States ; Department of Veterans Affairs, Birmingham VA Medical Center, United States
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