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Rigacci S, Miceli C, Nediani C, Berti A, Cascella R, Pantano D, Nardiello P, Luccarini I, Casamenti F, Stefani M. Oleuropein aglycone induces autophagy via the AMPK/mTOR signalling pathway: a mechanistic insight. Oncotarget 2016; 6:35344-57. [PMID: 26474288 PMCID: PMC4742109 DOI: 10.18632/oncotarget.6119] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/12/2015] [Indexed: 01/21/2023] Open
Abstract
The healthy effects of plant polyphenols, some of which characterize the so-called Mediterranean diet, have been shown to arise from epigenetic and biological modifications resulting, among others, in autophagy stimulation. Our previous work highlighted the beneficial effects of oleuropein aglycone (OLE), the main polyphenol found in the extra virgin olive oil, against neurodegeneration both in cultured cells and in model organisms, focusing, in particular, autophagy activation. In this study we investigated more in depth the molecular and cellular mechanisms of autophagy induction by OLE using cultured neuroblastoma cells and an OLE-fed mouse model of amylod beta (Aβ) deposition. We found that OLE triggers autophagy in cultured cells through the Ca2+-CAMKKβ-AMPK axis. In particular, in these cells OLE induces a rapid release of Ca2+ from the SR stores which, in turn, activates CAMKKβ, with subsequent phosphorylation and activation of AMPK. The link between AMPK activation and mTOR inhibition was shown in the OLE-fed animal model in which we found that decreased phospho-mTOR immunoreactivity and phosphorylated mTOR substrate p70 S6K levels match enhanced phospho-AMPK levels, supporting the idea that autophagy activation by OLE proceeds through mTOR inhibition. Our results agree with those reported for other plant polyphenols, suggesting a shared molecular mechanism underlying the healthy effects of these substances against ageing, neurodegeneration, cancer, diabetes and other diseases implying autophagy dysfunction.
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Affiliation(s)
- Stefania Rigacci
- Department of Experimental and Clinical Biomedical Sciences, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Caterina Miceli
- Department of Experimental and Clinical Biomedical Sciences, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Chiara Nediani
- Department of Experimental and Clinical Biomedical Sciences, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Andrea Berti
- Department of Experimental and Clinical Biomedical Sciences, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Daniela Pantano
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Pamela Nardiello
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Ilaria Luccarini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
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Abstract
Neurodegenerative diseases (NDDs) are a group of intractable diseases that significantly affect human health. To date, the pathogenesis of NDDs is still poorly understood and effective disease-modifying therapies for NDDs have not been established. NDDs share the common morphological characteristic of the deposition of abnormal proteins in the nervous system, including neurons. Autophagy is one of the major processes by which damaged organelles and abnormal proteins are removed from cells. Impairment of autophagy has been found to be involved in the pathogenesis of NDDs, and the regulation of autophagy may become a therapeutic strategy for NDDs. In recent years, some active compounds from plants have been found to regulate autophagy and exert neuroprotection against NDDs, including Alzheimer's disease, Parkinson's disease, Huntington's disease, spinal and bulbar muscular atrophy, spinocerebellar ataxia 3, and amyotrophic lateral sclerosis, via activating autophagy. In this paper, we review recent advances in the use of active ingredients from plants for the regulation of autophagy and treatment of NDDs.
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103
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Long-term treatment with nicotinamide induces glucose intolerance and skeletal muscle lipotoxicity in normal chow-fed mice: compared to diet-induced obesity. J Nutr Biochem 2016; 36:31-41. [PMID: 27567590 DOI: 10.1016/j.jnutbio.2016.07.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/06/2016] [Accepted: 07/05/2016] [Indexed: 12/11/2022]
Abstract
Nicotinamide (NAM), or vitamin B3, is an essential coenzyme for ATP synthesis and an inhibitor of sirtuin 1. Recently, conflicting results were reported regarding the treatment of NAM in type 2 diabetes and obesity. The aim of this study was to determine whether and how long-term treatment with NAM at lower dose would affect insulin sensitivity in mice fed chow diet. We treated mice with NAM (100 mg/kg/day) and normal chow for 8 weeks. Strikingly, NAM induced glucose intolerance and skeletal muscle lipid accumulation in nonobese mice. NAM impaired mitochondrial respiration capacity and energy production in skeletal muscle, in combination with increased expression of the mediators for mitophagy (p62, PINK1, PARK2 and NIX) and autophagy (FOXO3, Bnip3, CTSL, Beclin1 and LC-3b). Next, we treated mice with high-fat diet (HFD) and resveratrol (RSV; 100 mg/kg/day) for 8 weeks. RSV protected against HFD-induced insulin resistance and obesity. HFD increased skeletal muscle lipid content as well as NAM, but this increase was attenuated by RSV. In contrast to NAM, HFD enhanced fatty acid oxidative capacity. Muscle transcript levels of genes for mitophagy and autophagy were largely suppressed by HFD, whereas RSV did not rescue these effects. These differences suggest that skeletal muscle autophagy may represent adaptive response to NAM-induced lipotoxicity, whereas reduced autophagy in skeletal muscle may promote HFD-induced lipotoxicity. Our results demonstrate that chronic NAM supplementation in healthy individuals, although at lower dose than previously reported, is still detrimental to glucose homeostasis and skeletal muscle lipid metabolism.
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104
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Xuan F, Jian J. Epigallocatechin gallate exerts protective effects against myocardial ischemia/reperfusion injury through the PI3K/Akt pathway-mediated inhibition of apoptosis and the restoration of the autophagic flux. Int J Mol Med 2016; 38:328-36. [PMID: 27246989 DOI: 10.3892/ijmm.2016.2615] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 05/23/2016] [Indexed: 01/13/2023] Open
Abstract
Epigallocatechin gallate (EGCG), a polyphenol derived from green tea, exhibits a wide range of biological activities, including antioxidant, atherosclerosis and antitumor activities. In this study, the cardioprotective effects of EGCG on myocardial ischemia/reperfusion (I/R) injury in rats and the underlying mechanisms were investigated. A rat model of I/R injury was established by ligating the left anterior descending coronary artery for 30 min, followed by reperfusion for 2 h. The levels of I/R-induced creatine kinase-MB (CK-MB) and the release of lactate dehydrogenase (LDH), as well as the infarct size, cardiomyocyte apoptosis and cardiac functional impairment were examined and compared. Western blot analysis was carried out to elucidate the potential molecular mechanisms of action of EGCG. The results revealed that EGCG post-conditioning significantly decreased the levels of CK-MB and the release of LDH, reduced the myocardial infarct size, decreased the apoptotic rate and partially preserved heart function. Furthermore, EGCG decreased the expression of cleaved caspase-3 concomitantly with the upregulation of PI3K, and the phosphorylation of Akt and endothelial nitric oxide synthase (eNOS). It also inhibited I/R-induced overautophagy and promoted the clearance of autophagosomes, as evidenced by a decrease in the ratio of microtubule-associated protein 1 light chain 3 (LC3)-II/LC3-I, the downregulation of Beclin1, Atg5 and p62, and the upregulation of active cathepsin D. Additionally, we observed an increase in the phosphorylation levels of the mammalian target of rapamycin (mTOR) following treatment with EGCG. Taken together, the findings of this study demonstrate that, EGCG post-conditioning alleviates myocardial I/R injury by inhibiting apoptosis and restoring the autophagic flux, which is associated with several targets of the PI3K/Akt signaling pathway.
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Affiliation(s)
- Feifei Xuan
- Department of Pharmacology, Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Jie Jian
- Department of Pharmacology, Guilin Medical University, Guilin, Guangxi 541001, P.R. China
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105
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Yu L, Yu H, Li X, Jin C, Zhao Y, Xu S, Sheng X. P38 MAPK/miR-1 are involved in the protective effect of EGCG in high glucose-induced Cx43 downregulation in neonatal rat cardiomyocytes. Cell Biol Int 2016; 40:934-42. [PMID: 27306406 DOI: 10.1002/cbin.10637] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 06/11/2016] [Indexed: 01/04/2023]
Abstract
The remodeling of cardiac gap junctions contributes to various arrhythmias in a diabetic heart. We previously reported that Epigallocatechin-3-gallate (EGCG) attenuated connexin43 (Cx43) protein downregulation induced by high glucose (HG) in neonatal rat cardiomyocytes, but Cx43 mRNA expression was not affected. It indicated the possible mechanisms of post-transcriptional regulation, which still remains unclear. As microRNAs (miRNAs) regulate gene expression widely at post-transcriptional level, we measured miR-1/206 in cardiomyocytes treated with HG and EGCG by quantitative RT-PCR and investigated their relationship with signal transduction pathways. The results showed that HG induced miR-1/206 elevation by PKC MAPK pathway. Moreover, we tested the negative regulation effect of miR-1/206 on Cx43 protein by miRNAs transfection. EGCG, however, nearly abolished the HG-induced miR-1 augmentation via P38 MAPK pathway. Therefore, our study suggested that PKC-activated miR-1/206 expression might contribute to Cx43 downregulation in HG-treated cardiomyocytes, and EGCG conferred protective effect by inhibiting miR-1 elevation via P38 MAPK pathway.
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Affiliation(s)
- Lu Yu
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
| | - Hongmei Yu
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
| | - Xiaoting Li
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
| | - Chongying Jin
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
| | - Yanbo Zhao
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
| | - Shengjie Xu
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
| | - Xia Sheng
- Department of Cardiovascular Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou, Zhejiang, 310016, China
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106
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Chen JH, Lee MS, Wang CP, Hsu CC, Lin HH. Autophagic effects of Hibiscus sabdariffa leaf polyphenols and epicatechin gallate (ECG) against oxidized LDL-induced injury of human endothelial cells. Eur J Nutr 2016; 56:1963-1981. [PMID: 27318926 DOI: 10.1007/s00394-016-1239-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 05/25/2016] [Indexed: 02/07/2023]
Abstract
PURPOSE Oxidized low-density lipoprotein (ox-LDL) contributes to the pathogenesis of atherosclerosis by promoting vascular endothelial cell injury. Hibiscus sabdariffa leaf polyphenols (HLP), rich in flavonoids, have been shown to possess antioxidant and antiatherosclerotic activities. In this study, we examined the protective role of HLP and its main compound (-)-epicatechin gallate (ECG) in human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL in vitro. METHODS In a model of ox-LDL-impaired HUVECs, assessments of cell viability, cytotoxicity, cell proliferation, apoptosis, and autophagy were detected. To highlight the mechanisms of the antiapoptotic effects of HLP and ECG, the expressions of molecular proteins were measured by Western blotting, real-time PCR, and so on. RESULTS HLP or ECG improved the survival of HUVECs from ox-LDL-induced viability loss. In addition, HLP or ECG showed potential in reducing ox-LDL-dependent apoptosis. Next, the ox-LDL-induced formation of acidic vesicular organelles and upregulation of the autophagy-related genes were increased by HLP or ECG. The HLP-triggered autophagic flux was further confirmed by increasing the LC3-II level under the pretreatment of an autophagy inhibitor chloroquine. Molecular data indicated the autophagic effect of HLP or ECG might be mediated via class III PI3K/Beclin-1 and PTEN/class I PI3K/Akt cascade signaling, as demonstrated by the usage of a class III PI3K inhibitor 3-methyladenine (3-MA) and a PTEN inhibitor SF1670. CONCLUSIONS Our data imply that ECG-enriched HLP upregulates the autophagic pathway, which in turn led to reduce ox-LDL-induced HUVECs injury and apoptosis and provide a new mechanism for its antiatherosclerotic activity.
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Affiliation(s)
- Jing-Hsien Chen
- Department of Nutrition, Chung Shan Medical University, Taichung City, Taiwan
| | - Ming-Shih Lee
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, No. 110, Sec. 1, Jianguo N. Road, Taichung City, 40201, Taiwan.,Clinical Laboratory, Chung Shan Medical University Hospital, Taichung City, Taiwan
| | - Chi-Ping Wang
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, No. 110, Sec. 1, Jianguo N. Road, Taichung City, 40201, Taiwan.,Clinical Laboratory, Chung Shan Medical University Hospital, Taichung City, Taiwan
| | - Cheng-Chin Hsu
- Department of Nutrition, Chung Shan Medical University, Taichung City, Taiwan
| | - Hui-Hsuan Lin
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, No. 110, Sec. 1, Jianguo N. Road, Taichung City, 40201, Taiwan. .,Clinical Laboratory, Chung Shan Medical University Hospital, Taichung City, Taiwan.
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107
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Gu HF, Li HZ, Tang YL, Tang XQ, Zheng XL, Liao DF. Nicotinate-Curcumin Impedes Foam Cell Formation from THP-1 Cells through Restoring Autophagy Flux. PLoS One 2016; 11:e0154820. [PMID: 27128486 PMCID: PMC4851383 DOI: 10.1371/journal.pone.0154820] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 04/19/2016] [Indexed: 01/28/2023] Open
Abstract
Our previous studies have indicated that a novel curcumin derivate nicotinate-curcumin (NC) has beneficial effects on the prevention of atherosclerosis, but the precise mechanisms are not fully understood. Given that autophagy regulates lipid metabolism, the present study was designed to investigate whether NC decreases foam cell formation through restoring autophagy flux in oxidized low-density lipoprotein (ox-LDL)-treated THP-1 cells. Our results showed that ox-LDL (100 μg/ml) was accumulated in THP-1 cells and impaired autophagy flux. Ox-LDL-induced impairment of autophagy was enhanced by treatment with the autophagy inhibitor chloroquine (CQ) and rescued by the autophagy inducer rapamycin. The aggregation of ox-LDL was increased by CQ, but decreased by rapamycin. In addition, colocalization of lipid droplets with LC3-II was remarkably reduced in ox-LDL group. In contrast, NC (10 μM) rescued the impaired autophagy flux by significantly increasing level of LC3-II, the number of autophagolysosomes, and the degradation of p62 in ox-LDL-treated THP-1 cells. Inhibition of the PI3K-Akt-mTOR signaling was required for NC-rescued autophagy flux. Notably, our results showed that NC remarkably promoted the colocalization of lipid droplets with autophagolysosomes, increased efflux of cholesterol, and reduced ox-LDL accumulation in THP-1 cells. However, treatment with 3-methyladenine (3-MA) or CQ reduced the protective effects of NC on lipid accumulation. Collectively, the findings suggest that NC decreases lipid accumulation in THP-1 cells through restoring autophagy flux, and further implicate that NC may be a potential therapeutic reagent to reverse atherosclerosis.
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Affiliation(s)
- Hong-Feng Gu
- Department of Physiology, University of South China, Hengyang, People's Republic of China
- Institute of Neuroscience, University of South China, Hengyang, People's Republic of China
| | - Hai-Zhe Li
- Department of Neurology of the First Affiliated Hospital, University of South China, Hengyang, People's Republic of China
| | - Ya-Ling Tang
- Department of Physiology, University of South China, Hengyang, People's Republic of China
- Institute of Neuroscience, University of South China, Hengyang, People's Republic of China
| | - Xiao-Qing Tang
- Department of Physiology, University of South China, Hengyang, People's Republic of China
- Institute of Neuroscience, University of South China, Hengyang, People's Republic of China
| | - Xi-Long Zheng
- Smooth Muscle Research Group, Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan, Hunan University of Chinese Medicine, Changsha, People's Republic of China
| | - Duan-Fang Liao
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan, Hunan University of Chinese Medicine, Changsha, People's Republic of China
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108
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EGCG-mediated autophagy flux has a neuroprotection effect via a class III histone deacetylase in primary neuron cells. Oncotarget 2016; 6:9701-17. [PMID: 25991666 PMCID: PMC4496391 DOI: 10.18632/oncotarget.3832] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/26/2015] [Indexed: 01/04/2023] Open
Abstract
Prion diseases caused by aggregated misfolded prion protein (PrP) are transmissible neurodegenerative disorders that occur in both humans and animals. Epigallocatechin-3-gallate (EGCG) has preventive effects on prion disease; however, the mechanisms related to preventing prion diseases are unclear. We investigated whether EGCG, the main polyphenol in green tea, prevents neuron cell damage induced by the human prion protein. We also studied the neuroprotective mechanisms and proper signals mediated by EGCG. The results showed that EGCG protects the neuronal cells against human prion protein-induced damage through inhibiting Bax and cytochrome c translocation and autophagic pathways by increasing LC3-II and reducing and blocking p62 by using ATG5 small interfering (si) RNA and autophagy inhibitors. We further demonstrated that the neuroprotective effects of EGCG were exhibited by a class III histone deacetylase; sirt1 activation and the neuroprotective effects attenuated by sirt1 inactivation using sirt1 siRNA and sirtinol. We demonstrated that EGCG activated the autophagic pathways by inducing sirt1, and had protective effects against human prion protein-induced neuronal cell toxicity. These results suggest that EGCG may be a therapeutic agent for treatment of neurodegenerative disorders including prion diseases.
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109
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Abstract
Polo-like kinase 1 (Plk1), a key player in mitosis, is overexpressed in a wide range of tumor types and has been validated as a target for tumor therapy. In addition to its N-terminal kinase domain, Plk1 harbors a C-terminal protein-protein interaction domain, referred to as the polo-box domain (PBD). Because the PBD is unique to the five-member family of polo-like kinases, and its inhibition is sufficient to inhibit the enzyme, the Plk1 PBD is an attractive target for the inhibition of Plk1 function. Although peptide-based inhibitors are invaluable tools for elucidating the nature of the binding interface, small molecules are better suited for the induction of mitotic arrest and apoptosis in tumor cells by Plk1 inhibition. This review describes the considerable progress that has been made in developing small-molecule and peptide-based inhibitors of the Plk1 PBD.
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Affiliation(s)
- Angela Berg
- Leipzig University, Institute of Organic Chemistry, Johannisallee 29, 04103, Leipzig, Germany
| | - Thorsten Berg
- Leipzig University, Institute of Organic Chemistry, Johannisallee 29, 04103, Leipzig, Germany.
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110
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The Natural Polyphenol Epigallocatechin Gallate Protects Intervertebral Disc Cells from Oxidative Stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:7031397. [PMID: 27119009 PMCID: PMC4826942 DOI: 10.1155/2016/7031397] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/30/2016] [Accepted: 02/16/2016] [Indexed: 12/19/2022]
Abstract
Oxidative stress-related phenotypic changes and a decline in the number of viable cells are crucial contributors to intervertebral disc degeneration. The polyphenol epigallocatechin 3-gallate (EGCG) can interfere with painful disc degeneration by reducing inflammation, catabolism, and pain. In this study, we hypothesized that EGCG furthermore protects against senescence and/or cell death, induced by oxidative stress. Sublethal and lethal oxidative stress were induced in primary human intervertebral disc cells with H2O2 (total n = 36). Under sublethal conditions, the effects of EGCG on p53-p21 activation, proliferative capacity, and accumulation of senescence-associated β-galactosidase were tested. Further, the effects of EGCG on mitochondria depolarization and cell viability were analyzed in lethal oxidative stress. The inhibitor LY249002 was applied to investigate the PI3K/Akt pathway. EGCG inhibited accumulation of senescence-associated β-galactosidase but did not affect the loss of proliferative capacity, suggesting that EGCG did not fully neutralize exogenous radicals. Furthermore, EGCG increased the survival of IVD cells in lethal oxidative stress via activation of prosurvival PI3K/Akt and protection of mitochondria. We demonstrated that EGCG not only inhibits inflammation but also can enhance the survival of disc cells in oxidative stress, which makes it a suitable candidate for the development of novel therapies targeting disc degeneration.
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111
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Khalil H, Tazi M, Caution K, Ahmed A, Kanneganti A, Assani K, Kopp B, Marsh C, Dakhlallah D, Amer AO. Aging is associated with hypermethylation of autophagy genes in macrophages. Epigenetics 2016; 11:381-8. [PMID: 26909551 DOI: 10.1080/15592294.2016.1144007] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Autophagy is a biological process characterized by self-digestion and involves induction of autophagosome formation, leading to degradation of autophagic cargo. Aging is associated with the reduction of autophagy activity leading to neurodegenerative disorders, chronic inflammation, and susceptibility to infection; however, the underlying mechanism is unclear. DNA methylation by DNA methyltransferases reduces the expression of corresponding genes. Since macrophages are major players in inflammation and defense against infection we determined the differences in methylation of autophagy genes in macrophages derived from young and aged mice. We found that promoter regions of Atg5 and LC3B are hypermethylated in macrophages from aged mice and this is accompanied by low gene expression. Treatment of aged mice and their derived macrophages with methyltransferase inhibitor (2)-epigallocatechin-3-gallate (EGCG) or specific DNA methyltransferase 2 (DNMT2) siRNA restored the expression of Atg5 and LC3 in vivo and in vitro. Our study builds a foundation for the development of novel therapeutics aimed to improve autophagy in the elderly population and suggests a role for DNMT2 in DNA methylation activities.
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Affiliation(s)
- Hany Khalil
- a Department of Molecular Biology , Genetic Engineering and Biotechnology Research Institute, University of Sadat City , Sadat City , Egypt
| | - Mia Tazi
- b Department of Microbial Infection and Immunity , Center for Microbial Interface Biology, The Ohio State University , Columbus , OH.,c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
| | - Kyle Caution
- b Department of Microbial Infection and Immunity , Center for Microbial Interface Biology, The Ohio State University , Columbus , OH.,c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
| | - Amr Ahmed
- b Department of Microbial Infection and Immunity , Center for Microbial Interface Biology, The Ohio State University , Columbus , OH.,c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
| | - Apurva Kanneganti
- b Department of Microbial Infection and Immunity , Center for Microbial Interface Biology, The Ohio State University , Columbus , OH.,c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
| | - Kaivon Assani
- d The Research Institute at Nationwide Children's Hospital, The Ohio State University , Columbus , OH
| | - Benjamin Kopp
- d The Research Institute at Nationwide Children's Hospital, The Ohio State University , Columbus , OH
| | - Clay Marsh
- c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
| | - Duaa Dakhlallah
- c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
| | - Amal O Amer
- b Department of Microbial Infection and Immunity , Center for Microbial Interface Biology, The Ohio State University , Columbus , OH.,c The Davis Heart and Lung Research Institute, The Ohio State University , Columbus , OH
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112
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Almeida S, Alves MG, Sousa M, Oliveira PF, Silva BM. Are Polyphenols Strong Dietary Agents Against Neurotoxicity and Neurodegeneration? Neurotox Res 2016; 30:345-66. [PMID: 26745969 DOI: 10.1007/s12640-015-9590-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 12/10/2015] [Accepted: 12/12/2015] [Indexed: 12/21/2022]
Abstract
Life expectancy of most human populations has greatly increased as a result of factors including better hygiene, medical practice, and nutrition. Unfortunately, as humans age, they become more prone to suffer from neurodegenerative diseases and neurotoxicity. Polyphenols can be cheaply and easily obtained as part of a healthy diet. They present a wide range of biological activities, many of which have relevance for human health. Compelling evidence has shown that dietary phytochemicals, particularly polyphenols, have properties that may suppress neuroinflammation and prevent toxic and degenerative effects in the brain. The mechanisms by which polyphenols exert their action are not fully understood, but it is clear that they have a direct effect through their antioxidant activities. They have also been shown to modulate intracellular signaling cascades, including the PI3K-Akt, MAPK, Nrf2, and MEK pathways. Polyphenols also interact with a range of neurotransmitters, illustrating that these compounds can promote their health benefits in the brain through a direct, indirect, or complex action. We discuss whether polyphenols obtained from diet or food supplements are an effective strategy to prevent or treat neurodegeneration. We also discuss the safety, mechanisms of action, and the current and future relevance of polyphenols in clinical treatment of neurodegenerative diseases. As populations age, it is important to discuss the dietary strategies to avoid or counteract the effects of incurable neurodegenerative disorders, which already represent an enormous financial and emotional burden for health care systems, patients, and their families.
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Affiliation(s)
- Susana Almeida
- Department of Microscopy, Laboratory of Cell Biology and Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Marco G Alves
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506, Covilhã, Portugal
| | - Mário Sousa
- Department of Microscopy, Laboratory of Cell Biology and Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.,Centre for Reproductive Genetics Prof. Alberto Barros, Porto, Portugal
| | - Pedro F Oliveira
- Department of Microscopy, Laboratory of Cell Biology and Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.,I3S - Institute of Health Research and Innovation, University of Porto, Porto, Portugal
| | - Branca M Silva
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506, Covilhã, Portugal.
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113
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Chen Y, Huang L, Zhang H, Diao X, Zhao S, Zhou W. Reduction in Autophagy by (-)-Epigallocatechin-3-Gallate (EGCG): a Potential Mechanism of Prevention of Mitochondrial Dysfunction After Subarachnoid Hemorrhage. Mol Neurobiol 2016; 54:392-405. [PMID: 26742518 DOI: 10.1007/s12035-015-9629-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 12/15/2015] [Indexed: 11/25/2022]
Abstract
Mitochondrial dysfunction and subsequent autophagy, which are common features in central nervous system (CNS) disorders, were found to contribute to neuronal cell injury after subarachnoid hemorrhage (SAH). (-)-Epigallocatechin-3-gallate (EGCG), the main biological active of tea catechin, is well known for its beneficial effects in the treatment of CNS diseases. Here, the ability of EGCG to rescue cellular injury and mitochondrial function following the improvement of autophagic flux after SAH was investigated. As expected, EGCG-protected mitochondrial function depended on the inhibition of cytosolic Ca2+ concentration ([Ca2+]i) influx via voltage-gated calcium channels (VGCCs) and, consequently, mitochondrial Ca2+ concentration ([Ca2+]m) overload via mitochondrial Ca2+ uniporter (MCU). The attenuated [Ca2+]i and [Ca2+]m levels observed in the EGCG-treated group likely lessened oxyhemoglobin (OxyHb)-induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization, mitochondrial membrane permeability transition pore (mPTP) opening, reactive oxygen species (ROS), and cytochrosome c (cyt c) releasing. Subsequently, EGCG can restore the disrupted autophagy flux after SAH both at the initiation and formation stages by regulating Atg5, LC3B, and Becn-1 (Beclin-1) mRNA expressions. Thus, precondition EGCG resulted in autophagosomes and more autolysosomes compared with SAH group. As a result, EGCG pre-treatment increased the neurological score and decreased cell death. This study suggested that the mitochondrial dysfunction and abnormal autophagy flux synergistically contribute to SAH pathogenesis. Thus, EGCG can be regarded as a new pharmacological agent that targets both mitochondria and altered autophagy in SAH therapy.
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Affiliation(s)
- Ying Chen
- College of Life Sciences, Henan Normal University, Xinxiang, Henan, 453007, China.
| | - Liyong Huang
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, 453100, China
| | - Huiyong Zhang
- College of Life Science and Biotechnology, Xinxiang Medical University, Xinxiang, Henan, 453003, China
| | - Xiling Diao
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, 453100, China
| | - Shuyang Zhao
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, 453100, China
| | - Wenke Zhou
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, 453100, China
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Xu H, Wang Y, Chen Y, Zhang P, Zhao Y, Huang Y, Wang X, Sheng J. Subcellular Localization of Galloylated Catechins in Tea Plants [Camellia sinensis (L.) O. Kuntze] Assessed via Immunohistochemistry. FRONTIERS IN PLANT SCIENCE 2016; 7:728. [PMID: 27303422 PMCID: PMC4881381 DOI: 10.3389/fpls.2016.00728] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/12/2016] [Indexed: 05/20/2023]
Abstract
Galloylated catechins, as the main secondary metabolites in the tea plant, including (-)-epigallocatechin-3-gallate and (-)-epicatechin-3-gallate, comprise approximately three-quarters of all the tea plant catechins and have stronger effects than non-galloylated catechins, both on the product quality in tea processing and the pharmacological efficacy to human beings. The subcellular localization of galloylated catechins has been the primary focus of studies that assess biosynthesis and physiological functions. Classical histochemical localization staining reagents can not specifically detect galloylated catechins; thus, their subcellular localization remains controversial. In the present study, we generated a monoclonal antibody (mAb) against galloylated catechins, which can be used for the subcellular localization of galloylated catechins in the tea plant by immunohistochemistry. Direct ELISA and ForteBio Octet Red 96 System assay indicated the mAb could recognize the galloylated catechins with high specificities and affinities. In addition, tea bud was ascertained as the optimal tissue for freezing microtomic sections for immunohistochemistry. What's more, the high quality mAbs which exhibited excellent binding capability to galloylated catechins were utilized for the visualization of them via immunohistochemistry. Our findings demonstrated that vacuoles were the primary sites of localization of galloylated catechins at the subcellular level.
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Affiliation(s)
- Huanhuan Xu
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
- College of Food Science and Technology, Yunnan Agricultural UniversityKunming, China
| | - Ya Wang
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
- College of Food Science and Technology, Yunnan Agricultural UniversityKunming, China
| | - Yana Chen
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
| | - Pan Zhang
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
| | - Yi Zhao
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
| | - Yewei Huang
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
- College of Food Science and Technology, Yunnan Agricultural UniversityKunming, China
- *Correspondence: Jun Sheng, ; Xuanjun Wang, ; Yewei Huang,
| | - Xuanjun Wang
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
- College of Pu-er Tea, Yunnan Agricultural UniversityKunming, China
- State Key Laboratory for Conservation and Utilization of Bio-Resources in YunnanKunming, China
- *Correspondence: Jun Sheng, ; Xuanjun Wang, ; Yewei Huang,
| | - Jun Sheng
- Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural UniversityKunming, China
- Tea Research Center of YunnanKunming, China
- State Key Laboratory for Conservation and Utilization of Bio-Resources in YunnanKunming, China
- *Correspondence: Jun Sheng, ; Xuanjun Wang, ; Yewei Huang,
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Antibiotic resistance breakers: can repurposed drugs fill the antibiotic discovery void? Nat Rev Drug Discov 2015; 14:821-32. [DOI: 10.1038/nrd4675] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Interactions between Autophagy and Bacterial Toxins: Targets for Therapy? Toxins (Basel) 2015; 7:2918-58. [PMID: 26248079 PMCID: PMC4549733 DOI: 10.3390/toxins7082918] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/07/2023] Open
Abstract
Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.
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Chesser AS, Ganeshan V, Yang J, Johnson GVW. Epigallocatechin-3-gallate enhances clearance of phosphorylated tau in primary neurons. Nutr Neurosci 2015. [PMID: 26207957 DOI: 10.1179/1476830515y.0000000038] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVES Alzheimer's disease (AD) is a neurodegenerative disorder characterized by intracellular accumulations of phosphorylated forms of the microtubule binding protein tau. This study aimed to explore a novel mechanism for enhancing the clearance of these pathological tau species using the green tea flavonoid epigallocatechin-3-gallate (EGCG). EGCG is a potent antioxidant and an activator of the Nrf2 transcriptional pathway. Nrf2 activators including EGCG have shown promise in mitigating amyloid pathology in vitro and in vivo. This study assessed whether EGCG could also alter tau clearance. METHODS Rat primary cortical neuron cultures were treated on day in vitro 8 with EGCG and analyzed for changes in gene and protein expression using luciferase assay, q-PCR, and western blotting. RESULTS EGCG treatment led to a significant decrease in the protein levels of three AD-relevant phospho-tau epitopes. Unexpectedly, EGCG does not appear to be facilitating this effect through the Nrf2 pathway or by increasing autophagy in general. However, EGCG did significantly increase mRNA expression of the key autophagy adaptor proteins NDP52 and p62. DISCUSSION In this study, we show that EGCG enhances the clearance of AD-relevant phosphorylated tau species in primary neurons. Interestingly, this result appears to be independent of both Nrf2 activation and enhanced autophagy - two previously reported mechanisms of phytochemical-induced tau clearance. EGCG did significantly increase expression of two autophagy adaptor proteins. Taken together, these results demonstrate that EGCG has the ability to increase the clearance of phosphorylated tau species in a highly specific manner, likely through increasing adaptor protein expression.
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118
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Zhong L, Hu J, Shu W, Gao B, Xiong S. Epigallocatechin-3-gallate opposes HBV-induced incomplete autophagy by enhancing lysosomal acidification, which is unfavorable for HBV replication. Cell Death Dis 2015; 6:e1770. [PMID: 25996297 PMCID: PMC4669713 DOI: 10.1038/cddis.2015.136] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 02/06/2023]
Abstract
Epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, exhibits diverse beneficial properties, including antiviral activity. Autophagy is a cellular process that is involved in the degradation of long-lived proteins and damaged organelles. Recent evidence indicates that modulation of autophagy is a potential therapeutic strategy for various viral diseases. In the present study, we investigated the effect of EGCG on hepatitis B virus (HBV) replication and the possible involvement of autophagy in this process. Our results showed that HBV induced autophagosome formation, which was required for replication of itself. However, although EGCG efficiently inhibited HBV replication, it enhanced, but not inhibited, autophagosome formation in hepatoma cells. Further study showed that HBV induced an incomplete autophagy, while EGCG, similar to starvation, was able to induce a complete autophagic process, which appeared to be unfavorable for HBV replication. Furthermore, it was found that HBV induced an incomplete autophagy by impairing lysosomal acidification, while it lost this ability in the presence of EGCG. Taken together, these data demonstrated that EGCG treatment opposed HBV-induced incomplete autophagy via enhancing lysosomal acidification, which was unfavorable for HBV replication.
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Affiliation(s)
- L Zhong
- Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, Shanghai 200032, P.R. China
| | - J Hu
- Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, Shanghai 200032, P.R. China
| | - W Shu
- Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, Shanghai 200032, P.R. China
| | - B Gao
- Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, Shanghai 200032, P.R. China
| | - S Xiong
- Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, Shanghai 200032, P.R. China
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215006, P.R. China
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119
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Ding Y, Sun X, Chen Y, Deng Y, Qian K. Epigallocatechin gallate attenuated non-alcoholic steatohepatitis induced by methionine- and choline-deficient diet. Eur J Pharmacol 2015; 761:405-12. [PMID: 25967348 DOI: 10.1016/j.ejphar.2015.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 04/14/2015] [Accepted: 05/08/2015] [Indexed: 01/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) and its progressive form, nonalcoholic steatohepatitis (NASH), are the most common causes of chronic liver disease. In this study, we evaluated the effects of Epigallocatechin gallate (EGCG) on methionine- and choline-deficient (MCD) diet-induced NASH. Our data showed that EGCG significantly prevented MCD diet-induced liver and body weight loss. Histological analysis showed that EGCG inhibited MCD diet-induced steatohepatitis including fat accumulation and inflammatory cells infiltration. Biochemical analysis data showed that EGCG significantly reduced the elevation of plasma ALT and AST levels but increased plasma triglyceride and cholesterol contents. However, EGCG significantly inhibited hepatic triglyceride and cholesterol content in MCD diet fed mice. Consistent with histology results, EGCG treatment significantly inhibited MCD diet-induced IL-1β, IL-6, TNF-α and MCP-1 mRNA expression. As an antioxidant, EGCG treatment significant inhibited hepatic MDA contents and increased hepatic SOD contents. In addition, transforming growth factor (TGF)-β, collagen I-α1, tissue inhibitor of metalloproteinase 1 (TIMP-1) and α-smooth muscle actin (SMA) mRNA expression, which are markers of hepatic fibrosis, were markedly inhibited by EGCG treatment. Western blot data showed that EGCG inhibited Smad2 and Smad3 phosphorylation in the liver and LX-2 cells which were involved in TGF-β-induced pathway. Taken together, EGCG attenuated NASH induced by MCD diet associated with ameliorating fibrosis, oxidative stress, and hepatic inflammation. Our results indicate that EGCG has beneficial roles in the development of MCD diet-induced NASH.
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Affiliation(s)
- Yi Ding
- Department of Geriatrics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
| | - Xin Sun
- Department of Geriatrics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
| | - Yuning Chen
- Department of Geriatrics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
| | - Yue Deng
- Department of Geriatrics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
| | - Ke Qian
- Department of Geriatrics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China.
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Lee CG, Koo JH, Kim SG. Phytochemical regulation of Fyn and AMPK signaling circuitry. Arch Pharm Res 2015; 38:2093-105. [PMID: 25951818 DOI: 10.1007/s12272-015-0611-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 04/27/2015] [Indexed: 01/03/2023]
Abstract
During the past decades, phytochemical terpenoids, polyphenols, lignans, flavonoids, and alkaloids have been identified as antioxidative and cytoprotective agents. Adenosine monophosphate-activated protein kinase (AMPK) is a kinase that controls redox-state and oxidative stress in the cell, and serves as a key molecule regulating energy metabolism. Many phytochemicals directly or indirectly alter the AMPK pathway in distinct manners, exerting catabolic metabolism. Some of them are considered promising in the treatment of metabolic diseases such as type II diabetes, obesity, and hyperlipidemia. Another important kinase that regulates energy metabolism is Fyn kinase, a member of the Src family kinases that plays a role in various cellular responses such as insulin signaling, cell growth, oxidative stress and apoptosis. Phytochemical inhibition of Fyn leads to AMPK-mediated protection of the cell in association with increased antioxidative capacity and mitochondrial biogenesis. The kinases may work together to form a signaling circuitry for the homeostasis of energy conservation and expenditure, and may serve as targets of phytochemicals. This review is intended as a compilation of recent advancements in the pharmacological research of phytochemicals targeting Fyn and AMPK circuitry, providing information for the prevention and treatment of metabolic diseases and the accompanying tissue injuries.
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Affiliation(s)
- Chan Gyu Lee
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea.
| | - Ja Hyun Koo
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea.
| | - Sang Geon Kim
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea.
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121
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Sulforaphane protects human umbilical vein cells against lipotoxicity by stimulating autophagy via an AMPK-mediated pathway. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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122
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Hu F, Wei F, Wang Y, Wu B, Fang Y, Xiong B. EGCG synergizes the therapeutic effect of cisplatin and oxaliplatin through autophagic pathway in human colorectal cancer cells. J Pharmacol Sci 2015; 128:27-34. [PMID: 26003085 DOI: 10.1016/j.jphs.2015.04.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 03/20/2015] [Accepted: 04/03/2015] [Indexed: 12/31/2022] Open
Abstract
Application of the platinum-based chemotherapy for colorectal cancer is restricted due to its severe cytotoxic effects. In this study we used synergistic strategies by combining (-)-Epigallocatechin gallate (EGCG) with cisplatin or oxaliplatin to minimize the ill effects of platinum-based therapy. MTS assay was used to examine the effect of EGCG, cisplatin and oxaliplatin on the proliferation of human colorectal cancer DLD-1 and HT-29 cells. Autophagic process was evaluated by detection of LC3-II protein, autophagosome formation, and quantification of Acidic Vesicular. Treatment of DLD-1 and HT-29 cells with EGCG plus cisplatin or oxaliplatin showed a synergistic effect on inhibition of cell proliferation and induction of cell death. EGCG enhanced the effect of cisplatin and oxaliplatin-induced autophagy in DLD-1 and HT-29 cells, as characterized by the accumulation of LC3-II protein, the increase of acidic vesicular organelles (AVOs), and the formation of autophagosome. In addition, transfection of DLD-1 and HT-29 cells with siRNA against ATG genes reduced EGCG synergistic effect. Our findings suggest that combining EGCG with cisplatin or oxaliplatin could potentiate the cytotoxicity of cisplatin and oxaliplatin in colorectal cancer cells through autophagy related pathway.
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Affiliation(s)
- Fen Hu
- Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan 430071, China.
| | - Fei Wei
- State Key Laboratory of Virology, National Laboratory of Antiviral and Tumor of Traditional Chinese Medicine, Institute of Medical Virology, Research Center of Food and Drug Evaluation, School of Medicine, Wuhan University, Wuhan 430071, China.
| | - Yulei Wang
- Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan 430071, China.
| | - Bibo Wu
- Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan 430071, China.
| | - Yuan Fang
- Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan 430071, China.
| | - Bin Xiong
- Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan 430071, China.
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Yamagata K, Xie Y, Suzuki S, Tagami M. Epigallocatechin-3-gallate inhibits VCAM-1 expression and apoptosis induction associated with LC3 expressions in TNFα-stimulated human endothelial cells. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2015; 22:431-437. [PMID: 25925964 DOI: 10.1016/j.phymed.2015.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/18/2015] [Accepted: 01/27/2015] [Indexed: 06/04/2023]
Abstract
Tumor necrosis factor alpha (TNF-α) promotes the expression of adhesion molecules and induces endothelial dysfunction, a process that can lead to atherosclerosis. Green tea consumption can inhibit endothelial dysfunction and attenuate the development of arteriosclerosis. The purpose of this study was to examine whether epigallocatechin-3-gallate (EGCG) prevents TNF-α-dependent endothelial dysfunction. Here, we compared the regulatory effects of the green tea components EGCG and L-theanine against TNF-α-induced stimulation of adhesion molecule expression and apoptosis induction, which is associated with autophagy. Monocytic cell adhesion to human endothelial cells was measured using a fluorescently-labeled cell line, U-937. Caspase 3/7 activity was examined with a fluorescent probe and fluorescence microscopy. In addition, we analyzed the expression of several genes by RT-PCR. TNF-α-modulation of LC3 and VCAM1 protein levels were investigated by Western blot (WB). TNF-α induced adhesion of U937 cells to endothelial cells, and gene expression associated with adhesion molecules and apoptosis. On the other hand, EGCG and L-theanine inhibited TNF-α-induced adhesion of U937 cells to endothelial cells and inhibited increases in ICAM1, CCL2 and VCAM1 expression. Furthermore, EGCG and L-theanine inhibited TNF-α-induced apoptosis-related gene expression (e.g., CASP9), and caspase activity while inhibiting TNFα-induced VCAM1, LC3A and LC3B protein expression. Meanwhile, treatment of endothelial cells with autophagy inhibitor 3-methyladenine (3-MA) blocked EGCG-induced expression of CASP9. Together, these results indicate that EGCG can modulate TNF-α-induced monocytic cell adhesion, apoptosis and autophagy. We thus conclude that EGCG might be beneficial for inhibiting TNF-α-mediated human endothelial disorders by affecting LC3 expression-related processes.
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Affiliation(s)
- Kazuo Yamagata
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University (NUBS), Fujisawa, Japan.
| | - Yajie Xie
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University (NUBS), Fujisawa, Japan
| | - Sayaka Suzuki
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University (NUBS), Fujisawa, Japan
| | - Motoki Tagami
- Department of Internal Medicine, Sanraku Hospital, Chiyoda-Ku, Tokyo, Japan
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Novel Mechanisms of Herbal Therapies for Inhibiting HMGB1 Secretion or Action. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:456305. [PMID: 25821489 PMCID: PMC4363608 DOI: 10.1155/2015/456305] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/24/2014] [Accepted: 10/01/2014] [Indexed: 12/11/2022]
Abstract
High mobility group box 1 (HMGB1) is an evolutionarily conserved protein and is constitutively expressed in virtually all types of cells. In response to microbial infections, HMGB1 is secreted from activated immune cells to orchestrate rigorous inflammatory responses. Here we review the distinct mechanisms by which several herbal components inhibit HMGB1 action or secretion, such as by modulating inflammasome activation, autophagic degradation, or endocytic uptake. In light of the reciprocal interactions between these cellular processes, it is possible to develop more effective combinational herbal therapies for the clinical management of inflammatory diseases.
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125
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Irimie AI, Braicu C, Zanoaga O, Pileczki V, Gherman C, Berindan-Neagoe I, Campian RS. Epigallocatechin-3-gallate suppresses cell proliferation and promotes apoptosis and autophagy in oral cancer SSC-4 cells. Onco Targets Ther 2015; 8:461-70. [PMID: 25759589 PMCID: PMC4346003 DOI: 10.2147/ott.s78358] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is the major bioactive component of green tea. Our experimental data indicated that EGCG treatment suppresses cell proliferation of SSC-4 human oral squamous cell carcinoma (OSCC), the effect being dose- and time-dependent. In parallel was observed the activation of apoptosis and autophagy, in response to EGCG exposure in SSC-4 cells. Treatment with EGCG activates the expression of the BAD, BAK, FAS, IGF1R, WNT11, and ZEB1 genes and inhibits CASP8, MYC, and TP53. All of these results suggest that EGCG has an excellent potential to become a therapeutic compound for patients with OSCC, by inducing tumor cell death via apoptosis and autophagy.
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Affiliation(s)
- Alexandra Iulia Irimie
- Department of Prosthodontics and Dental Materials, Faculty of Dental Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Cornelia Braicu
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Oana Zanoaga
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Valentina Pileczki
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania ; Department of Analytical Chemistry, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Claudia Gherman
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania ; Department of Functional Genomics and Experimental Pathology, The Oncology Institute "Prof Dr. Ion Chiricuta", Cluj-Napoca, Romania
| | - Ioana Berindan-Neagoe
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania ; Department of Functional Genomics and Experimental Pathology, The Oncology Institute "Prof Dr. Ion Chiricuta", Cluj-Napoca, Romania ; Department of Immunology, Faculty of Medicine, University of Medicine and Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania ; Department of Experimental Therapeutics MD Anderson Cancer Center Houston, TX, USA
| | - Radu Septimiu Campian
- Department of Oral Rehabilitation, Faculty of Dental Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
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Niso-Santano M, Malik SA, Pietrocola F, Bravo-San Pedro JM, Mariño G, Cianfanelli V, Ben-Younès A, Troncoso R, Markaki M, Sica V, Izzo V, Chaba K, Bauvy C, Dupont N, Kepp O, Rockenfeller P, Wolinski H, Madeo F, Lavandero S, Codogno P, Harper F, Pierron G, Tavernarakis N, Cecconi F, Maiuri MC, Galluzzi L, Kroemer G. Unsaturated fatty acids induce non-canonical autophagy. EMBO J 2015; 34:1025-41. [PMID: 25586377 DOI: 10.15252/embj.201489363] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 12/19/2014] [Indexed: 12/21/2022] Open
Abstract
To obtain mechanistic insights into the cross talk between lipolysis and autophagy, two key metabolic responses to starvation, we screened the autophagy-inducing potential of a panel of fatty acids in human cancer cells. Both saturated and unsaturated fatty acids such as palmitate and oleate, respectively, triggered autophagy, but the underlying molecular mechanisms differed. Oleate, but not palmitate, stimulated an autophagic response that required an intact Golgi apparatus. Conversely, autophagy triggered by palmitate, but not oleate, required AMPK, PKR and JNK1 and involved the activation of the BECN1/PIK3C3 lipid kinase complex. Accordingly, the downregulation of BECN1 and PIK3C3 abolished palmitate-induced, but not oleate-induced, autophagy in human cancer cells. Moreover, Becn1(+/-) mice as well as yeast cells and nematodes lacking the ortholog of human BECN1 mounted an autophagic response to oleate, but not palmitate. Thus, unsaturated fatty acids induce a non-canonical, phylogenetically conserved, autophagic response that in mammalian cells relies on the Golgi apparatus.
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Affiliation(s)
- Mireia Niso-Santano
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Shoaib Ahmad Malik
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Government College University, Faisalabad, Pakistan
| | - Federico Pietrocola
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Université Paris Sud/Paris 11, Le Kremlin Bicêtre, France
| | - José Manuel Bravo-San Pedro
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Guillermo Mariño
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Valentina Cianfanelli
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Amena Ben-Younès
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Rodrigo Troncoso
- Advanced Center for Chronic Disease (ACCDiS), Faculty of Chemical & Pharmaceutical Sciences/Faculty of Medicine, University of Chile, Santiago, Chile Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Faculty of Medicine, Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile
| | - Maria Markaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Valentina Sica
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Université Paris Sud/Paris 11, Le Kremlin Bicêtre, France
| | - Valentina Izzo
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Kariman Chaba
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Chantal Bauvy
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France INSERM, U1151, Paris, France Institut Necker Enfants-Malades, Paris, France
| | - Nicolas Dupont
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France INSERM, U1151, Paris, France Institut Necker Enfants-Malades, Paris, France
| | - Oliver Kepp
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France INSERM, U1138, Paris, France Cell Biology & Metabolomics Platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - Patrick Rockenfeller
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria BioTechMed Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria BioTechMed Graz, Graz, Austria
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria BioTechMed Graz, Graz, Austria
| | - Sergio Lavandero
- Advanced Center for Chronic Disease (ACCDiS), Faculty of Chemical & Pharmaceutical Sciences/Faculty of Medicine, University of Chile, Santiago, Chile Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Faculty of Medicine, Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Patrice Codogno
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France INSERM, U1151, Paris, France Institut Necker Enfants-Malades, Paris, France
| | - Francis Harper
- Gustave Roussy Comprehensive Cancer Center, Villejuif, France CNRS, UMR8122, Villejuif, France
| | - Gérard Pierron
- Gustave Roussy Comprehensive Cancer Center, Villejuif, France CNRS, UMR8122, Villejuif, France
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Francesco Cecconi
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark Laboratory of Molecular Neuroembryology, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Maria Chiara Maiuri
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France
| | - Lorenzo Galluzzi
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France Gustave Roussy Comprehensive Cancer Center, Villejuif, France INSERM, U1138, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Guido Kroemer
- Equipe 11 labellisée par la Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France INSERM, U1138, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France Cell Biology & Metabolomics Platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
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127
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Abstract
Cardiovascular disease is the leading cause of death worldwide. As such, there is great interest in identifying novel mechanisms that govern the cardiovascular response to disease-related stress. First described in failing hearts, autophagy within the cardiovascular system has been widely characterized in cardiomyocytes, cardiac fibroblasts, endothelial cells, vascular smooth muscle cells, and macrophages. In all cases, a window of optimal autophagic activity appears to be critical to the maintenance of cardiovascular homeostasis and function; excessive or insufficient levels of autophagic flux can each contribute to heart disease pathogenesis. In this Review, we discuss the potential for targeting autophagy therapeutically and our vision for where this exciting biology may lead in the future.
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128
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Shan HM, Shi Y, Quan J. Identification of green tea catechins as potent inhibitors of the polo-box domain of polo-like kinase 1. ChemMedChem 2015; 10:158-63. [PMID: 25196850 DOI: 10.1002/cmdc.201402284] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Indexed: 12/21/2022]
Abstract
Polo-like kinase 1 (PLK1) plays crucial functions in multiple stages of mitosis and is considered to be a potential drug target for cancer therapy. The functions of PLK1 are mediated by its N-terminal kinase domain and C-terminal polo-box domain (PBD). Most inhibitors targeting the kinase domain of PLK1 have a selectivity issue because of a high degree of structural conservation within kinase domains of all protein kinases. Here, we combined virtual and experimental screenings to identify green tea catechins as potent inhibitors of the PLK1 PBD. Initially, (-)-epigallocatechin, one of the main components of green tea polyphenols, was found to significantly block the binding of fluorescein-labeled phosphopeptide to the PBD at a concentration of 10 μm. Next, additional catechins were evaluated for their dose-dependent inhibition of the PBD and preliminary structure-activity relationships were derived. Cellular analysis further showed that catechins interfere with the proper subcellular localization of PLK1, lead to cell-cycle arrest in the S and G2M phases, and induce growth inhibition of several human cancer cell types, such as breast adenocarcinoma (MCF7), lung adenocarcinoma (A549), and cervical adenocarcinoma (HeLa). Our data provides new insight into understanding the anticancer activities of green tea catechins.
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Affiliation(s)
- Hong-Mei Shan
- Key Laboratory of Chemical Genomics, School of Chemical Biology & Biotechnology, Peking University, Shenzhen Graduate School, Shenzhen 518055 (China)
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129
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Bao GQ, He L, Lee D, D'Angelo J, Wang HC. An ongoing search for potential targets and therapies for lethal sepsis. Mil Med Res 2015; 2:20. [PMID: 26257917 PMCID: PMC4529709 DOI: 10.1186/s40779-015-0047-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 07/20/2015] [Indexed: 01/15/2023] Open
Abstract
Sepsis, which refers to a systemic inflammatory response syndrome resulting from a microbial infection, represents the leading cause of death in intensive care units. The pathogenesis of sepsis remains poorly understood although it is attributable to dysregulated immune responses orchestrated by innate immune cells that are sequentially released early (e.g., tumor necrosis factor(TNF), interleukin-1(IL-1), and interferon-γ(IFN-γ)) and late (e.g., high mobility group box 1(HMGB1)) pro-inflammatory mediators. As a ubiquitous nuclear protein, HMGB1 can be passively released from pathologically damaged cells, thereby converging infection and injury on commonly dysregulated inflammatory responses. We review evidence that supports extracellular HMGB1 as a late mediator of inflammatory diseases and discuss the potential of several Chinese herbal components as HMGB1-targeting therapies. We propose that it is important to develop strategies for specifically attenuating injury-elicited inflammatory responses without compromising the infection-mediated innate immunity for the clinical management of sepsis and other inflammatory diseases.
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Affiliation(s)
- Guo-Qiang Bao
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA.,The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030 USA.,Department of General Surgery, Tangdu Hospital, The 4th Military Medical University, Xi'an, Shaanxi 710032 China
| | - Li He
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - David Lee
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA
| | - John D'Angelo
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA
| | - Hai-Chao Wang
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA.,The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030 USA
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130
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Gu HF, Nie YX, Tong QZ, Tang YL, Zeng Y, Jing KQ, Zheng XL, Liao DF. Epigallocatechin-3-gallate attenuates impairment of learning and memory in chronic unpredictable mild stress-treated rats by restoring hippocampal autophagic flux. PLoS One 2014; 9:e112683. [PMID: 25393306 PMCID: PMC4231069 DOI: 10.1371/journal.pone.0112683] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/10/2014] [Indexed: 01/07/2023] Open
Abstract
Epigallocatechin gallate (EGCG) is a major polyphenol in green tea with beneficial effects on the impairment in learning and memory. Autophagy is a cellular process that protects neurons from stressful conditions. The present study was designed to investigate whether EGCG can rescue chronic unpredictable mild stress (CUMS)-induced cognitive impairment in rats and whether its protective effect involves improvement of autophagic flux. As expected, our results showed that CUMS significantly impaired memory performance and inhibited autophagic flux as indicated by elevated LC3-II and p62 protein levels. At the same time, we observed an increased neuronal loss and activated mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase (p70S6k) signaling in the CA1 regions. Interestingly, chronic treatment with EGCG (25 mg/kg, i.p.) significantly improved those behavioral alterations, attenuated histopathological abnormalities in hippocampal CA1 regions, reduced amyloid beta1-42 (Aβ1-42) levels, and restored autophagic flux. However, blocking autophagic flux with chloroquine, an inhibitor of autophagic flux, reversed these effects of EGCG. Taken together, these findings suggest that the impaired autophagy in CA1 regions of CUMS rats may contribute to learning and memory impairment. Therefore, we conclude that EGCG attenuation of CUMS-induced learning and memory impairment may be through rescuing autophagic flux.
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MESH Headings
- Amyloid beta-Peptides/genetics
- Amyloid beta-Peptides/metabolism
- Animals
- Autoantigens/genetics
- Autoantigens/metabolism
- Autophagy/drug effects
- CA1 Region, Hippocampal/drug effects
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/pathology
- Catechin/analogs & derivatives
- Catechin/antagonists & inhibitors
- Catechin/pharmacology
- Chloroquine/pharmacology
- Chronic Disease
- Cognitive Dysfunction/drug therapy
- Cognitive Dysfunction/etiology
- Cognitive Dysfunction/genetics
- Cognitive Dysfunction/physiopathology
- Gene Expression Regulation
- Male
- Maze Learning/drug effects
- Memory/drug effects
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Nootropic Agents/antagonists & inhibitors
- Nootropic Agents/pharmacology
- Peptide Fragments/genetics
- Peptide Fragments/metabolism
- Rats
- Rats, Wistar
- Ribosomal Protein S6 Kinases, 70-kDa/genetics
- Ribosomal Protein S6 Kinases, 70-kDa/metabolism
- Signal Transduction
- Stress, Psychological/complications
- Stress, Psychological/drug therapy
- Stress, Psychological/genetics
- Stress, Psychological/physiopathology
- TOR Serine-Threonine Kinases/genetics
- TOR Serine-Threonine Kinases/metabolism
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Affiliation(s)
- Hong-Feng Gu
- Department of Physiology & Institute of Neuroscience, University of South China, Hengyang, People's Republic of China
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan, Hunan University of Chinese Medicine, Changsha, People's Republic of China
| | - Ya-Xiong Nie
- Department of Neurology of the First Affiliated Hospital, University of South China, Hengyang, People's Republic of China
| | - Qiao-Zhen Tong
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan, Hunan University of Chinese Medicine, Changsha, People's Republic of China
| | - Ya-Ling Tang
- Department of Physiology & Institute of Neuroscience, University of South China, Hengyang, People's Republic of China
| | - Yang Zeng
- Department of Neurology of the First Affiliated Hospital, University of South China, Hengyang, People's Republic of China
| | - Kai-Quan Jing
- Department of Neurology of the First Affiliated Hospital, University of South China, Hengyang, People's Republic of China
| | - Xi-Long Zheng
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan, Hunan University of Chinese Medicine, Changsha, People's Republic of China
- Smooth Muscle Research Group, Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Duan-Fang Liao
- Smooth Muscle Research Group, Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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131
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Sadowska-Bartosz I, Ott C, Grune T, Bartosz G. Posttranslational protein modifications by reactive nitrogen and chlorine species and strategies for their prevention and elimination. Free Radic Res 2014; 48:1267-84. [PMID: 25119970 DOI: 10.3109/10715762.2014.953494] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteins are subject to various posttranslational modifications, some of them being undesired from the point of view of metabolic efficiency. Prevention of such modifications is expected to provide new means of therapy of diseases and decelerate the process of aging. In this review, modifications of proteins by reactive nitrogen species and reactive halogen species, is briefly presented and means of prevention of these modifications and their sequelae are discussed, including the denitrase activity and inhibitors of myeloperoxidase.
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Affiliation(s)
- I Sadowska-Bartosz
- Department of Biochemistry and Cell Biology, University of Rzeszów , Rzeszów , Poland
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132
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Stefani M, Rigacci S. Beneficial properties of natural phenols: highlight on protection against pathological conditions associated with amyloid aggregation. Biofactors 2014; 40:482-93. [PMID: 24890399 DOI: 10.1002/biof.1171] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 11/05/2022]
Abstract
Mediterranean and Asian diets are currently considered as the most healthy traditional feeding habits effective against risk of age-associated, particularly cardiovascular and neurodegenerative, diseases. A common feature of these two regimens is the abundance of foods and beverages of plant origin (green tea, extra virgin olive oil, red wine, spices, berries, and aromatic herbs) that are considered responsible for the observed beneficial effects. Epidemiological data suggest that the phenolic component remarkably enriched in these foods plays an important role in reducing the incidence of amyloid diseases, pathological conditions associated to tissue deposition of toxic protein aggregates responsible for progressive functional deterioration. Great effort is being spent to provide knowledge on the effects of several natural phenols in this context, moving from the test tube to animal models and, more slowly, to the patient's bed. An emerging feature that makes these molecules increasingly attractive for amyloid disease prevention and therapy is their wide spectrum of activity: recent pieces of evidence suggest that they can inhibit the production of amyloidogenic peptides from precursors, increase antioxidant enzyme activity, activate autophagy and reduce inflammation. Our concept should than shift from considering natural phenols simply as antioxidants or, at the best, as amyloid aggregation inhibitors, to describing them as potentially multitargeting drugs. A main concern is the low bioavailability of such compounds and efforts aimed at improving it are underway, with encapsulation strategies being the most promising ones.
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Affiliation(s)
- Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio,", University of Florence, Florence, Italy; Research Centre on the Molecular Basis of Neurodegeneration, University of Florence, Florence, Italy
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133
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Guo F, Li X, Peng J, Tang Y, Yang Q, Liu L, Wang Z, Jiang Z, Xiao M, Ni C, Chen R, Wei D, Wang GX. Autophagy regulates vascular endothelial cell eNOS and ET-1 expression induced by laminar shear stress in an ex vivo perfused system. Ann Biomed Eng 2014; 42:1978-88. [PMID: 24838486 DOI: 10.1007/s10439-014-1033-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/10/2014] [Indexed: 02/08/2023]
Abstract
Vascular endothelial cell function responds to steady laminar shear stress; however, the underlying mechanisms are not fully elucidated. In the present study, we examined the effect of steady laminar shear stress on vascular endothelial cell autophagy and endothelial cell nitric oxide synthase (eNOS) and endothelin-1 (ET-1) expression using an ex vivo perfusion system. Human vascular endothelial cells and common arteries of New Zealand rabbits were pretreated with or without rapamycin or 3-MA for 30 min. These were then placed in an ex vivo cell perfusion system or an ex vivo organ perfusion system under static conditions (0 dynes/cm2) or steady laminar shear stress (5 or 15 dynes/cm2) for 1 h. In both ex vivo perfusion vascular endothelial cells and vascular vessel segment, steady laminar shear stress promoted autophagy and eNOS expression and inhibited ET-1 expression. Compared with steady laminar shear stress treatment alone, the pretreatment of autophagy inducer rapamycin obviously strengthened the expression of eNOS and decreased the expression of ET-1 in both the 5 and 15 dynes/cm2 treatment groups. Moreover, when pretreated with the autophagy inhibitor 3-MA, the eNOS expression was obviously inhibited and the ET-1 expression was reversed. These findings demonstrate that autophagy is upregulated under steady laminar shear stress, improving endothelial cell maintenance of vascular tone function.
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Affiliation(s)
- Fengxia Guo
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, University of South China, Hengyang, 421001, China
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134
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Zhou J, Farah BL, Sinha RA, Wu Y, Singh BK, Bay BH, Yang CS, Yen PM. Epigallocatechin-3-gallate (EGCG), a green tea polyphenol, stimulates hepatic autophagy and lipid clearance. PLoS One 2014; 9:e87161. [PMID: 24489859 PMCID: PMC3906112 DOI: 10.1371/journal.pone.0087161] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/18/2013] [Indexed: 12/19/2022] Open
Abstract
Epigallocatechin gallate (EGCG) is a major polyphenol in green tea that has been shown to have anti-inflammatory, anti-cancer, anti-steatotic effects on the liver. Autophagy also mediates similar effects; however, it is not currently known whether EGCG can regulate hepatic autophagy. Here, we show that EGCG increases hepatic autophagy by promoting the formation of autophagosomes, increasing lysosomal acidification, and stimulating autophagic flux in hepatic cells and in vivo. EGCG also increases phosphorylation of AMPK, one of the major regulators of autophagy. Importantly, siRNA knockdown of AMPK abrogated autophagy induced by EGCG. Interestingly, we observed lipid droplet within autophagosomes and autolysosomes and increased lipid clearance by EGCG, suggesting it promotes lipid metabolism by increasing autophagy. In mice fed with high-fat/western style diet (HFW; 60% energy as fat, reduced levels of calcium, vitamin D3, choline, folate, and fiber), EGCG treatment reduces hepatosteatosis and concomitantly increases autophagy. In summary, we have used genetic and pharmacological approaches to demonstrate EGCG induction of hepatic autophagy, and this may contribute to its beneficial effects in reducing hepatosteatosis and potentially some other pathological liver conditions.
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Affiliation(s)
- Jin Zhou
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Benjamin Livingston Farah
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Rohit Anthony Sinha
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Brijesh Kumar Singh
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Boon-Huat Bay
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chung S. Yang
- Departments of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Paul Michael Yen
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
- Sarah W. Stedman Nutrition and Metabolism Center, Departments of Medicine and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
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135
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New insights into the mechanisms of polyphenols beyond antioxidant properties; lessons from the green tea polyphenol, epigallocatechin 3-gallate. Redox Biol 2014; 2:187-95. [PMID: 24494192 PMCID: PMC3909779 DOI: 10.1016/j.redox.2013.12.022] [Citation(s) in RCA: 506] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 12/20/2013] [Accepted: 12/20/2013] [Indexed: 12/16/2022] Open
Abstract
Green tea is rich in polyphenol flavonoids including catechins. Epigallocatechin 3-gallate (EGCG) is the most abundant and potent green tea catechin. EGCG has been extensively studied for its beneficial health effects as a nutriceutical agent. Based upon its chemical structure, EGCG is often classified as an antioxidant. However, treatment of cells with EGCG results in production of hydrogen peroxide and hydroxyl radicals in the presence of Fe (III). Thus, EGCG functions as a pro-oxidant in some cellular contexts. Recent investigations have revealed many other direct actions of EGCG that are independent from anti-oxidative mechanisms. In this review, we discuss these novel molecular mechanisms of action for EGCG. In particular, EGCG directly interacts with proteins and phospholipids in the plasma membrane and regulates signal transduction pathways, transcription factors, DNA methylation, mitochondrial function, and autophagy to exert many of its beneficial biological actions. Many biological actions of EGCG are mediated by specific mechanisms other than its well-known anti-oxidant properties. EGCG is a pro-oxidant per se in some biological contexts. EGCG directly interacts with cell surface membrane proteins and specific known receptors. Treatment of cells with EGCG regulates specific intracellular signaling pathways and transcription. Specific biological actions of EGCG are regulated in a concentration-dependent manner.
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136
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Xu H, Xiong S, Wang H, Zhang M, Yu Y. The evidence and the possible significance of autophagy in degeneration model of human cervical end-plate cartilage. Exp Ther Med 2013; 7:537-542. [PMID: 24520242 PMCID: PMC3919868 DOI: 10.3892/etm.2013.1465] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 12/02/2013] [Indexed: 01/20/2023] Open
Abstract
The aim of this study was to observe autophagy in chondrocytes from degenerative human cervical vertebral end-plates and to investigate the significance of variations in autophagy in the degeneration of cervical vertebral end-plate chondrocytes. Cartilage end-plates were obtained from 48 inpatients admitted to hospital between February 2011 and August 2012. The patients were divided into the control group (n=17) with cervical vertebral fracture or dislocation and the cervical spondylosis group (n=31) with cervical spondylotic myelopathy. End-plate chondrocytes were isolated via enzyme digestion and then cultured in vitro. The cells were stained with toluidine blue and hematoxylin-eosin (H&E). A laser scanning confocal microscope and monodansylcadaverine (MDC) were used to reveal autophagy in the end-plate chondrocytes. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect mRNA expression of type II collagen and aggrecan. Western blotting was conducted to detect LC3 proteins. The chondrocytes isolated from the degenerative human cervical end-plates were cultured successfully in vitro. The morphology of the cells from the cervical spondylosis group tended to exhibit changes in spindle morphology compared with the control group. Autophagic bodies were stained with MDC. LC3 proteins were visible in the intracellular and perinuclear regions under the laser scanning confocal microscope. The mRNA expression levels (relative to those of β-actin) of aggrecan (0.715±0.194) and type II collagen (0.628±0.254) in the cervical spondylosis group were markedly decreased compared with those in the control group (0.913±0.254 and 0.845±0.186, respectively; both P<0.05). The LC3-II/LC3-I ratio was observed to be significantly reduced in the cervical spondylosis group by Western blot analysis. Autophagy has an important role in human cervical disc degeneration. The regulation of autophagy may prevent disc degeneration in cartilage end-plate cells.
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Affiliation(s)
- Hongguang Xu
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Shouliang Xiong
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Hong Wang
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Min Zhang
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Yunfei Yu
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
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137
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Menard C, Bastianetto S, Quirion R. Neuroprotective effects of resveratrol and epigallocatechin gallate polyphenols are mediated by the activation of protein kinase C gamma. Front Cell Neurosci 2013; 7:281. [PMID: 24421757 PMCID: PMC3872731 DOI: 10.3389/fncel.2013.00281] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/15/2013] [Indexed: 01/08/2023] Open
Abstract
Polyphenols such as epigallocatechin gallate (EGCG) and resveratrol have received a great deal of attention because they may contribute to the purported neuroprotective action of the regular consumption of green tea and red wine. Many studies, including those published by our group, suggest that this protective action includes their abilities to prevent the neurotoxic effects of beta-amyloid, a protein whose accumulation likely plays a pivotal role in Alzheimer's disease. Moreover, the scavenging activities of polyphenols on reactive oxygen species and their inhibitory action of cyclooxygenase likely explain, at least in part, their antioxidant and anti-inflammatory activities. Besides these well-documented properties, the modulatory action of these polyphenols on intracellular signaling pathways related to cell death/survival (e.g., protein kinase C, PKC) has yet to be investigated in detail. Using rat hippocampal neuronal cells, we aimed to investigate here the effects of EGCG and resveratrol on cell death induced by GF 109203X, a selective inhibitor of PKC. The MTT/resazurin and spectrin assays indicated that EGCG and resveratrol protected against GF 109203X-induced cell death and cytoskeleton degeneration, with a maximal effect at 1 and 3 μM, respectively. Moreover, immunofluorescence data revealed that cells treated with these polyphenols increased PKC gamma (γ) activation and promoted neuronal interconnections. Finally, we found that the protective effects of both polyphenols on the cytoskeleton and synaptic plasticity were mediated by the PKCγ subunit. Taken together, the results suggest that PKC, and more specifically its γ subunit, plays a critical role in the protective action of EGCG and resveratrol on neuronal integrity.
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Affiliation(s)
- Caroline Menard
- Laboratory of Neuroendocrinology of Aging, Centre Hospitalier de l'Université de Montréal Research Center Montreal, QC, Canada ; Department of Medicine, University of Montreal Montreal, QC, Canada ; Douglas Mental Health University Institute, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada
| | - Stéphane Bastianetto
- Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
| | - Rémi Quirion
- Douglas Mental Health University Institute, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada
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138
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Min KJ, Kwon TK. Anticancer effects and molecular mechanisms of epigallocatechin-3-gallate. Integr Med Res 2013; 3:16-24. [PMID: 28664074 PMCID: PMC5481703 DOI: 10.1016/j.imr.2013.12.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 11/26/2013] [Accepted: 12/03/2013] [Indexed: 12/11/2022] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is a type of catechin found in green tea. EGCG exhibits a variety of activities, including anti-inflammatory, antidiabetes, antiobesity, and antitumor. In this review, we focus on the antitumor effects of EGCG. EGCG inhibits carcinogen activity, tumorigenesis, proliferation, and angiogenesis, and induces cell death. These effects are associated with modulation of reactive oxygen species (ROS) production. Although EGCG has a dual function of antioxidant and pro-oxidant potential, EGCG-mediated modulation of ROS production is reported to be responsible for its anticancer effects. The EGCG-mediated inhibition of nuclear factor-κB signaling is also associated with inhibition of migration, angiogenesis, and cell viability. Activation of mitogen-activated protein kinases activity upregulates the anticancer effect of EGCG on migration, invasion, and apoptosis. In addition, EGCG could also induce epigenetic modification by inhibition of DNA methyltransferase activity and regulation of acetylation on histone, leading to an upregulation of apoptosis. Although EGCG promotes strong anticancer effects by multiple mechanisms, further studies are needed to define the use of EGCG in clinical treatment.
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Affiliation(s)
- Kyoung-jin Min
- Corresponding authors. Department of Immunology, School of Medicine, Keimyung University, 2800 Dalgubeol-daero, Dalseo-gu, Daegu 704-701, Korea.
| | - Taeg Kyu Kwon
- Corresponding authors. Department of Immunology, School of Medicine, Keimyung University, 2800 Dalgubeol-daero, Dalseo-gu, Daegu 704-701, Korea.
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139
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Jang HJ, Ridgeway SD, Kim JA. Effects of the green tea polyphenol epigallocatechin-3-gallate on high-fat diet-induced insulin resistance and endothelial dysfunction. Am J Physiol Endocrinol Metab 2013; 305:E1444-51. [PMID: 24148349 PMCID: PMC3882381 DOI: 10.1152/ajpendo.00434.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Insulin resistance, a hallmark of metabolic disorders, is a risk factor for diabetes and cardiovascular disease. Impairment of insulin responsiveness in vascular endothelium contributes to insulin resistance. The reciprocal relationship between insulin resistance and endothelial dysfunction augments the pathophysiology of metabolism and cardiovascular functions. The most abundant green tea polyphenol, epigallocatechin-3-gallate (EGCG), has been shown to have vasodilator action in vessels by activation of endothelial nitric oxide synthase (eNOS). However, it is not known whether EGCG has a beneficial effect in high-fat diet (HFD)-induced endothelial dysfunction. Male C57BL/6J mice were fed either a normal chow diet (NCD) or HFD with or without EGCG supplement (50 mg·kg(-1)·day(-1)) for 10 wk. Mice fed a HFD with EGCG supplement gained less body weight and showed improved insulin sensitivity. In vehicle-treated HFD mice, endothelial function was impaired in response to insulin but not to acetylcholine, whereas the EGCG-treated HFD group showed improved insulin-stimulated vasodilation. Interestingly, EGCG intake reduced macrophage infiltration into aortic tissues in HFD mice. Treatment with EGCG restored the insulin-stimulated phosphorylation of eNOS, insulin receptor substrate-1 (IRS-1), and protein kinase B (Akt), which was inhibited by palmitate (200 μM, 5 h) in primary bovine aortic endothelial cells. From these results, we conclude that supplementation of EGCG improves glucose tolerance, insulin sensitivity, and endothelial function. The results suggest that EGCG may have beneficial health effects in glucose metabolism and endothelial function through modulating HFD-induced inflammatory response.
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Affiliation(s)
- Hyun-Ju Jang
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama
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140
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Li CP, Yao J, Tao ZF, Li XM, Jiang Q, Yan B. Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: a potential role for reducing UVB light-induced retinal damage. Biochem Biophys Res Commun 2013; 438:739-45. [PMID: 23916613 DOI: 10.1016/j.bbrc.2013.07.097] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 07/24/2013] [Indexed: 12/19/2022]
Abstract
Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.
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Affiliation(s)
- Chao-Peng Li
- Eye hospital, Nanjing Medical University, Nanjing 210029, China
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141
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PATEL S. Green Tea as a Nutraceutical: The Latest Developments. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2013. [DOI: 10.3136/fstr.19.923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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