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Yang CS, Zhang J, Zhang L, Huang J, Wang Y. Mechanisms of body weight reduction and metabolic syndrome alleviation by tea. Mol Nutr Food Res 2015; 60:160-74. [PMID: 26577614 DOI: 10.1002/mnfr.201500428] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/09/2015] [Accepted: 11/06/2015] [Indexed: 12/13/2022]
Abstract
Tea, a popular beverage made from leaves of the plant Camellia sinensis, has been shown to reduce body weight, alleviate metabolic syndrome, and prevent diabetes and cardiovascular diseases in animal models and humans. Such beneficial effects have generally been observed in most human studies when the level of tea consumption was three to four cups (600-900 mg tea catechins) or more per day. Green tea is more effective than black tea. In spite of numerous studies, the fundamental mechanisms for these actions still remain unclear. From a review of the literature, we propose that the two major mechanisms are: (i) decreasing absorption of lipids and proteins by tea constituents in the intestine, thus reducing calorie intake; and (ii) activating AMP-activated protein kinase by tea polyphenols that are bioavailable in the liver, skeletal muscle, and adipose tissues. The relative importance of these two mechanisms depends on the types of tea and diet consumed by individuals. The activated AMP-activated protein kinase would decrease gluconeogenesis and fatty acid synthesis and increase catabolism, leading to body weight reduction and metabolic syndrome alleviation. Other mechanisms and the health relevance of these beneficial effects of tea consumption remain to be further investigated.
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Affiliation(s)
- Chung S Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.,International Joint Research Laboratory of Tea Chemistry and Health Effects, Anhui Agricultural University, Hefei, Anhui, P. R. China
| | - Jinsong Zhang
- International Joint Research Laboratory of Tea Chemistry and Health Effects, Anhui Agricultural University, Hefei, Anhui, P. R. China.,State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui, P. R. China
| | - Le Zhang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.,International Joint Research Laboratory of Tea Chemistry and Health Effects, Anhui Agricultural University, Hefei, Anhui, P. R. China
| | - Jinbao Huang
- International Joint Research Laboratory of Tea Chemistry and Health Effects, Anhui Agricultural University, Hefei, Anhui, P. R. China.,State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui, P. R. China
| | - Yijun Wang
- International Joint Research Laboratory of Tea Chemistry and Health Effects, Anhui Agricultural University, Hefei, Anhui, P. R. China.,State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui, P. R. China
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102
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Santamarina AB, Oliveira JL, Silva FP, Carnier J, Mennitti LV, Santana AA, de Souza GHI, Ribeiro EB, Oller do Nascimento CM, Lira FS, Oyama LM. Green Tea Extract Rich in Epigallocatechin-3-Gallate Prevents Fatty Liver by AMPK Activation via LKB1 in Mice Fed a High-Fat Diet. PLoS One 2015; 10:e0141227. [PMID: 26536464 PMCID: PMC4633218 DOI: 10.1371/journal.pone.0141227] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/05/2015] [Indexed: 01/19/2023] Open
Abstract
Supplementation with epigallocatechin-3-gallate has been determined to aid in the prevention of obesity. Decaffeinated green tea extract appears to restore a normal hepatic metabolic profile and attenuate high-fat diet (HFD)-induced effects, thereby preventing non-alcoholic fatty liver disease in mice. Mice were maintained on either a control diet (CD) or HFD for 16 weeks and supplemented with either water or green tea extract (50 mg/kg/day). The body mass increase, serum adiponectin level, and lipid profile were measured over the course of the treatment. Furthermore, the AMPK pathway protein expression in the liver was measured. From the fourth week, the weight gain in the CD + green tea extract (CE) group was lower than that in the CD + water (CW) group. From the eighth week, the weight gain in the HFD + water (HFW) group was found to be higher than that in the CW group. Moreover, the weight gain in the HFD + green tea extract (HFE) group was found to be lower than that in the HFW group. Carcass lipid content was found to be higher in the HFW group than that in the CW and HFE groups. Serum analysis showed reduced non-esterified fatty acid level in the CE and HFE groups as compared with their corresponding placebo groups. Increased adiponectin level was observed in the same groups. Increased VLDL-TG secretion was observed in the HFW group as compared with the CW and HFE groups. Increased protein expression of AdipoR2, SIRT1, pLKB1, and pAMPK was observed in the HFE group, which explained the reduced expression of ACC, FAS, SREBP-1, and ChREBP in this group. These results indicate that the effects of decaffeinated green tea extract may be related to the activation of AMPK via LKB1 in the liver of HFD-fed mice.
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Affiliation(s)
| | - Juliana L. Oliveira
- Departamento de Fisiologia—Universidade Federal de São Paulo, São Paulo, Brazil
| | - Fernanda P. Silva
- Departamento de Fisiologia—Universidade Federal de São Paulo, São Paulo, Brazil
| | - June Carnier
- Departamento de Fisiologia—Universidade Federal de São Paulo, São Paulo, Brazil
| | - Laís V. Mennitti
- Programa de Pós-Graduação Interdisciplinar em Ciências da Saúde—Universidade Federal de São Paulo, Santos, Brazil
| | - Aline A. Santana
- Departamento de Fisiologia—Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Eliane B. Ribeiro
- Departamento de Fisiologia—Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Fábio S. Lira
- Exercise and Immunometabolism Research Group, Department of Physical Education, Universidade Estadual Paulista, UNESP, Presidente Prudente, SP, Brazil
| | - Lila M. Oyama
- Departamento de Fisiologia—Universidade Federal de São Paulo, São Paulo, Brazil
- * E-mail:
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103
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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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104
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Meijer AJ, Lorin S, Blommaart EF, Codogno P. Regulation of autophagy by amino acids and MTOR-dependent signal transduction. Amino Acids 2015; 47:2037-63. [PMID: 24880909 PMCID: PMC4580722 DOI: 10.1007/s00726-014-1765-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 05/12/2014] [Indexed: 01/05/2023]
Abstract
Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins and of the elimination of damaged or functionally redundant organelles. Proper functioning of this process is essential for cell survival. Dysregulation of autophagy has been implicated in the etiology of several pathologies. The history of the studies on the interrelationship between amino acids, MTOR signaling and autophagy is the subject of this review. The mechanisms responsible for the stimulation of MTOR-mediated signaling, and the inhibition of autophagy, by amino acids have been studied intensively in the past but are still not completely clarified. Recent developments in this field are discussed.
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Affiliation(s)
- Alfred J Meijer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
| | - Séverine Lorin
- UPRES EA4530, Université Paris-Sud, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, 92296, Châtenay-Malabry Cedex, France
| | - Edward F Blommaart
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Patrice Codogno
- INSERM U1151-CNRS UMR 8253, Université Paris Descartes, 14 rue Maria Helena Vieira Da Silva CS61431, 75993, Paris Cedex 14, France
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105
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Alphitolic acid, an anti-inflammatory triterpene, induces apoptosis and autophagy in oral squamous cell carcinoma cells, in part, through a p53-dependent pathway. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.07.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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106
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Radad K, Moldzio R, Al-Shraim M, Kranner B, Krewenka C, Rausch WD. Recent advances in autophagy-based neuroprotection. Expert Rev Neurother 2015; 15:195-205. [PMID: 25614954 DOI: 10.1586/14737175.2015.1002087] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Macroautophagy is a highly regulated intracellular process that, under certain circumstances, delivers cytoplasmic components to the lysosomes for degradation. It consists of several sequential steps including initiation and nucleation, double membrane formation and elongation, formation and maturation of autophagosomes and finally autophagosomes/lysosomes fusion and degradation of intra-autophagosomal contents by lysosomal enzymes. After decades of considering autophagy as a cell death pathway, it has recently been shown to have a survival function through clearing of protein aggregates and damaged cytoplasmic organelles in response to a variety of stress conditions. Most recently, there is increasing evidence from literature revealing that autophagy induction may combat neurodegeneration. In the light of this, our current review tried to address the recent advances in the role of induced autophagy in neuroprotection with a particular focus on its contribution in the most common neurodegenerative disorders like Alzheimer's disease, Parkinson's disease and Huntington's disease.
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Affiliation(s)
- Khaled Radad
- Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt
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107
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Singh P, Bast F. Screening of multi-targeted natural compounds for receptor tyrosine kinases inhibitors and biological evaluation on cancer cell lines, in silico and in vitro. Med Oncol 2015; 32:233. [PMID: 26298529 DOI: 10.1007/s12032-015-0678-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 08/08/2015] [Indexed: 12/27/2022]
Abstract
Receptors for growth factors encompass within the superfamily of receptor tyrosine kinases and are known to regulate numerous biological processes including cellular growth, proliferation, metabolism, survival, cell differentiation and apoptosis. These receptors have recently caught the attention of the researchers as an attractive target to combat cancer owing to the evidence suggesting their over-expression in cancer cells. Therefore, we studied receptor-based molecular docking of IR (PDB; 3ETA), IGF1R (PDB; 1K3A), EGFR (PDB; 1M17), VEGFIR (PDB; 3HNG), and VEGFIIR (PDB; 2OH4) against natural compounds. Further, in vitro investigation of the biological effect of lead molecules in an array of cancer cell lines was done. All selected natural compounds were docked with the X-ray crystal structure of selected protein by employing GLIDE (Grid-based Ligand Docking with Energetics) Maestro 9.6. InterBioScreen natural compounds docked with each selected protein molecules by using GLIDE high throughput virtual screening. On the basis of Gscore, we select 20 compounds along with 68 anticancer compounds for GLIDE extra precision molecular docking. It was discovered in this study that compound epigallocatechin gallate (EGCG) yielded magnificent Gscore with IGF1R (PDB; 1K3A) and VEGFIIR (PDB; 2OH4), and protein-ligand interactions are chart out. Effect of EGCG on biological activity such as mRNA expression of selected protein, cell proliferation, oxidative stress, and cell migration was reported after the 48 h treatments in cancer cell lines. The RT-PCR densitometric bands analysis showed that compound EGCG reduced the mRNA expression of IGF1R, VEGFIIR, and mTOR at 80 μM concentration. Moreover, EGCG significantly reduced cell proliferation and ROS generation after 48 h treatments. Our result also indicated a reduction in the potential for cell migration that might show in vivo anti-metastasis activity of EGCG.
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Affiliation(s)
- Pushpendra Singh
- Centre for Biosciences, School of Basic and Applied Sciences, Central University of Punjab, Bathinda, 151001, Punjab, India
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108
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O’Donovan TR, Rajendran S, O’Reilly S, O’Sullivan GC, McKenna SL. Lithium Modulates Autophagy in Esophageal and Colorectal Cancer Cells and Enhances the Efficacy of Therapeutic Agents In Vitro and In Vivo. PLoS One 2015; 10:e0134676. [PMID: 26248051 PMCID: PMC4527721 DOI: 10.1371/journal.pone.0134676] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/13/2015] [Indexed: 12/22/2022] Open
Abstract
Many epithelial cancers, particularly gastrointestinal tract cancers, remain poor prognosis diseases, due to resistance to cytotoxic therapy and local or metastatic recurrence. We have previously shown that apoptosis incompetent esophageal cancer cells induce autophagy in response to chemotherapeutic agents and this can facilitate their recovery. However, known pharmacological inhibitors of autophagy could not enhance cytotoxicity. In this study, we have examined two well known, clinically approved autophagy inducers, rapamycin and lithium, for their effects on chemosensitivity in apoptosis incompetent cancer cells. Both lithium and rapamycin were shown to induce autophagosomes in esophageal and colorectal cancer cells by western blot analysis of LC3 isoforms, morphology and FACS quantitation of Cyto-ID or mCherry-GFP-LC3. Analysis of autophagic flux indicates inefficient autophagosome processing in lithium treated cells, whereas rapamycin treated cells showed efficient flux. Viability and recovery was assessed by clonogenic assays. When combined with the chemotherapeutic agent 5-fluorouracil, rapamycin was protective. In contrast, lithium showed strong enhancement of non-apoptotic cell death. The combination of lithium with 5-fluorouracil or oxaliplatin was then tested in the syngenic mouse (balb/c) colorectal cancer model—CT26. When either chemotherapeutic agent was combined with lithium a significant reduction in tumor volume was achieved. In addition, survival was dramatically increased in the combination group (p < 0.0001), with > 50% of animals achieving long term cure without re-occurrence (> 1 year tumor free). Thus, combination treatment with lithium can substantially improve the efficacy of chemotherapeutic agents in apoptosis deficient cancer cells. Induction of compromised autophagy may contribute to this cytotoxicity.
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Affiliation(s)
- Tracey R. O’Donovan
- Leslie C. Quick Laboratory, Cork Cancer Research Centre, BioSciences Institute, University College Cork, Cork, Ireland
| | - Simon Rajendran
- Leslie C. Quick Laboratory, Cork Cancer Research Centre, BioSciences Institute, University College Cork, Cork, Ireland
| | - Seamus O’Reilly
- Department of Medical Oncology, Cork University Hospital, Cork, Ireland
| | - Gerald C. O’Sullivan
- Leslie C. Quick Laboratory, Cork Cancer Research Centre, BioSciences Institute, University College Cork, Cork, Ireland
| | - Sharon L. McKenna
- Leslie C. Quick Laboratory, Cork Cancer Research Centre, BioSciences Institute, University College Cork, Cork, Ireland
- * E-mail:
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109
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Chen L, Ye HL, Zhang G, Yao WM, Chen XZ, Liang G. Effect of (-)-epigallocatechin-3- O-gallate on autophagic signaling in HepG2 cells. Shijie Huaren Xiaohua Zazhi 2015; 23:3022-3028. [DOI: 10.11569/wcjd.v23.i19.3022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the changes of autophagy in hepatocellular carcinoma (HCC) HepG2 cells in response to (-)-epigallocatechin-3-O-gallate (EGCG), and to explore its impact on cell proliferation and death.
METHODS: HepG2 cells were routinely cultured and re-plated in Dulbecco's modified eagle's medium (DMEM) in the presence of EGCG of different concentrations. Transmission electron microscopic technique was used to record the formation of autophagosomes in HepG2 cells. Real-time RT-PCR and Western blot were used to detect the mRNA and protein expression of autophagy-related genes, respectively. MTT and trypan blue assays were carried out to determine the cellular proliferation and death. Autophagic intervention experiment was performed to evaluate whether changes in autophagy are involved in the anti-cancer efficacy of EGCG in HCC.
RESULTS: The proliferation of HepG2 cells was significantly inhibited by EGCG and was negatively related to the concentrations of this compound (r = -0.9341, P < 0.001). Doses of EGCG that could effectively inhibit the proliferation of HepG2 cells significantly decreased the mRNA and protein expression of Beclin1 and Atg5, with increments of P62 named autophagic substrate as well as substantially reduced numbers of autophagasomes found in these cells. Moreover, up-regulating autophagy with rapamycin was found to apparently impair the effect of EGCG in killing HepG2 cells (t = 9.95, P < 0.01), while 3-MA, an autophagy inhibitor, dramatically exaggerated the anti-cancer effects of EGCG (t = 22.82, P < 0.01).
CONCLUSION: EGCG substantially inhibits cell proliferation and promotes cell death in HCC cells via down-regulation of autophagy, which indicates a novel critical pharmacological mechanism of EGCG for hepatoma therapy.
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110
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Renaud J, Nabavi SF, Daglia M, Nabavi SM, Martinoli MG. Epigallocatechin-3-Gallate, a Promising Molecule for Parkinson's Disease? Rejuvenation Res 2015; 18:257-69. [PMID: 25625827 DOI: 10.1089/rej.2014.1639] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, and it is characterized by the loss of the neurotransmitter dopamine and neuronal degeneration in the substantia nigra pars compacta. Thus far, current therapeutic strategies have failed to address neuronal degeneration. It has been reported that overproduction of reactive oxygen species, resulting in oxidative stress, and neuroinflammation play an important role in neurodegenerative diseases through the induction of macromolecular oxidative damage and modulation of intracellular signaling pathways concurring to neuronal cell death. Indeed, anti-oxidant and anti-inflammatory drugs have been the subject of recommendation as a complementary therapy alongside an effective symptomatic treatment to hamper the progression of PD. Today, much attention is paid to polyphenols in light of their potent capacity to reduce oxidative stress and inflammation, while having much fewer side effects than most other drugs. Camellia sinensis L. is the most common ancient herbal tea prepared as a beverage worldwide and it possesses numerous beneficial effects on human health. Epigallocatechin-3-gallate is the best-known bioactive component of C. sinensis and is recognized to exert potent neuroprotective effects against oxidative stress, neuroinflammation, protein aggregation, autophagy, and neuronal cell death in vitro as well as in vivo. The present review appraises the available literature on the beneficial role of epigallocatechin-3-gallate pertaining to dopaminergic degeneration characteristic of PD with particular emphasis on its possible mechanisms of action.
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Affiliation(s)
- Justine Renaud
- 1 Department of Medical Biology and Research Group in Neuroscience, Université du Québec , Trois-Rivières, Québec, Canada
| | - Seyed Fazel Nabavi
- 2 Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences , Tehran, Iran
| | - Maria Daglia
- 3 Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia , Italy
| | - Seyed Mohammad Nabavi
- 2 Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences , Tehran, Iran
| | - Maria-Grazia Martinoli
- 1 Department of Medical Biology and Research Group in Neuroscience, Université du Québec , Trois-Rivières, Québec, Canada
- 4 Department of Psychiatry and Neuroscience, Université Laval and CHU Research Center , Québec, Canada
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111
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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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112
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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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113
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Abstract
Autophagy is a conserved quality-control pathway that degrades cytoplasmic contents in lysosomes. Autophagy degrades lipid droplets through a process termed lipophagy. Starvation and an acute lipid stimulus increase autophagic sequestration of lipid droplets and their degradation in lysosomes. Accordingly, liver-specific deletion of the autophagy gene Atg7 increases hepatic fat content, mimicking the human condition termed nonalcoholic fatty liver disease. In this review, we provide insights into the molecular regulation of lipophagy, discuss fundamental questions related to the mechanisms by which autophagosomes recognize lipid droplets and how ATG proteins regulate membrane curvature for lipid droplet sequestration, and comment on the possibility of cross talk between lipophagy and cytosolic lipases in lipid mobilization. Finally, we discuss the contribution of lipophagy to the pathophysiology of human fatty liver disease. Understanding how lipophagy clears hepatocellular lipid droplets could provide new ways to prevent fatty liver disease, a major epidemic in developed nations.
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Affiliation(s)
- Nuria Martinez-Lopez
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Rajat Singh
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
- Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York 10461
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, New York 10461
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114
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Cai Y, Zhao L, Qin Y, Wu XQ. EGCG Blocked Phenylephrin-Induced Hypertrophy in H9C2 Cardiomyocytes, by Activating AMPK-Dependent Pathway. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:203-10. [PMID: 25954124 PMCID: PMC4422959 DOI: 10.4196/kjpp.2015.19.3.203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 10/02/2014] [Accepted: 01/23/2015] [Indexed: 12/31/2022]
Abstract
AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism. Previous studies have shown that activation of AMPK results in suppression of cardiac myocyte hypertrophy via inhibition of the p70S6 kinase (p70S6K) and eukaryotic elongation factor-2 (eEF2) signaling pathways. Epigallocatechin-3-gallate (EGCG), the major polyphenol found in green tea, possesses multiple protective effects on the cardiovascular system including cardiac hypertrophy. However, the molecular mechanisms has not been well investigated. In this study, we found that EGCG could significantly reduce natriuretic peptides type A (Nppa), brain natriuretic polypeptide (BNP) mRNA expression and decrease cell surface area in H9C2 cardiomyocytes stimulated with phenylephrine (PE). Moreover, we showed that AMPK is activated in H9C2 cardiomyocytes by EGCG, and AMPK-dependent pathway participates in the inhibitory effects of EGCG on cardiac hypertrophy. Taken together, our findings provide the first evidence that the effect of EGCG against cardiac hypertrophy may be attributed to its activation on AMPK-dependent signaling pathway, suggesting the therapeutic potential of EGCG on the prevention of cardiac remodeling in patients with pressure overload hypertrophy.
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Affiliation(s)
- Yi Cai
- Guangzhou Research Institute of Snake Venom, China
| | - Li Zhao
- Guangzhou Research Institute of Snake Venom, China
| | - Yuan Qin
- Guangzhou Research Institute of Snake Venom, China
| | - Xiao-Qian Wu
- Department of Pharmacology, Guangzhou Medical University, Guangzhou, 510182, Guangdong, P.R. China
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115
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Parafati M, Lascala A, Morittu VM, Trimboli F, Rizzuto A, Brunelli E, Coscarelli F, Costa N, Britti D, Ehrlich J, Isidoro C, Mollace V, Janda E. Bergamot polyphenol fraction prevents nonalcoholic fatty liver disease via stimulation of lipophagy in cafeteria diet-induced rat model of metabolic syndrome. J Nutr Biochem 2015; 26:938-48. [PMID: 26025327 DOI: 10.1016/j.jnutbio.2015.03.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 03/24/2015] [Accepted: 03/31/2015] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in industrialized countries. Defective autophagy of lipid droplets (LDs) in hepatocytes, also known as lipophagy, has recently been identified as a possible pathophysiological mechanism of NAFLD. Experimental and epidemiological evidence suggests that dietary polyphenols may prevent NAFLD. To address this hypothesis and analyze the underlying mechanisms, we supplemented bergamot polyphenol fraction (BPF) to cafeteria (CAF) diet-fed rats, a good model for pediatric metabolic syndrome and NAFLD. BPF treatment (50 mg/kg/day supplemented with drinking water, 3 months) potently counteracted the pathogenic increase of serum triglycerides and had moderate effects on blood glucose and obesity in this animal model. Importantly, BPF strongly reduced hepatic steatosis as documented by a significant decrease in total lipid content (-41.3% ± 12% S.E.M.), ultrasound examination and histological analysis of liver sections. The morphometric analysis of oil-red stained sections confirmed a dramatic reduction in LDs parameters such as total LD area (48.5% ± 15% S.E.M.) in hepatocytes from CAF+BPF rats. BPF-treated livers showed increased levels of LC3 and Beclin 1 and reduction of SQSTM1/p62, suggesting autophagy stimulation. Consistent with BPF stimulation of lipophagy, higher levels of LC3II were found in the LD subcellular fractions of BPF-expose livers. This study demonstrates that the liver and its lipid metabolism are the main targets of bergamot flavonoids, supporting the concept that supplementation of BPF is an effective strategy to prevent NAFLD.
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Affiliation(s)
- Maddalena Parafati
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy; Interregional Research Center for Food Safety and Health, Catanzaro, Italy
| | - Antonella Lascala
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy
| | - Valeria Maria Morittu
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy
| | - Francesca Trimboli
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy
| | - Antonia Rizzuto
- Department of Experimental and Clinical Medicine, Magna Graecia University, Campus Germaneto, Catanzaro, Italy
| | - Elvira Brunelli
- Department of Ecology, University of Calabria, Rende, Cosenza, Italy
| | | | - Nicola Costa
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy
| | - Domenico Britti
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy
| | | | - Ciro Isidoro
- Laboratory of Molecular Pathology, Department of Health Sciences, Università del Piemonte Orientale "A. Avogadro", Novara, Italy
| | - Vincenzo Mollace
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy; Interregional Research Center for Food Safety and Health, Catanzaro, Italy
| | - Elzbieta Janda
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, Catanzaro, Italy; Interregional Research Center for Food Safety and Health, Catanzaro, Italy
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116
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In vitro toxicity of epigallocatechin gallate in rat liver mitochondria and hepatocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:476180. [PMID: 25918582 PMCID: PMC4397056 DOI: 10.1155/2015/476180] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/15/2015] [Accepted: 03/03/2015] [Indexed: 12/20/2022]
Abstract
Epigallocatechin-3-gallate (EGCG) is the main compound of green tea with well-described antioxidant, anti-inflammatory, and tumor-suppressing properties. However, EGCG at high doses was reported to cause liver injury. In this study, we evaluated the effect of EGCG on primary culture of rat hepatocytes and on rat liver mitochondria in permeabilized hepatocytes. The 24-hour incubation with EGCG in concentrations of 10 μmol/L and higher led to signs of cellular injury and to a decrease in hepatocyte functions. The effect of EGCG on the formation of reactive oxygen species (ROS) was biphasic. While low doses of EGCG decreased ROS production, the highest tested dose induced a significant increase in ROS formation. Furthermore, we observed a decline in mitochondrial membrane potential in cells exposed to EGCG when compared to control cells. In permeabilized hepatocytes, EGCG caused damage of the outer mitochondrial membrane and an uncoupling of oxidative phosphorylation. EGCG in concentrations lower than 10 μmol/L was recognized as safe for hepatocytes in vitro.
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117
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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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118
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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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119
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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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120
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Wang S, Sun Z, Dong S, Liu Y, Liu Y. Molecular interactions between (-)-epigallocatechin gallate analogs and pancreatic lipase. PLoS One 2014; 9:e111143. [PMID: 25365042 PMCID: PMC4218840 DOI: 10.1371/journal.pone.0111143] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 09/28/2014] [Indexed: 01/06/2023] Open
Abstract
The molecular interactions between pancreatic lipase (PL) and four tea polyphenols (EGCG analogs), like (−)-epigallocatechin gallate (EGCG), (−)-gallocatechin gallate (GCG), (−)-epicatechin gallate (ECG), and (−)-epigallocatechin (EC), were studied from PL activity, conformation, kinetics and thermodynamics. It was observed that EGCG analogs inhibited PL activity, and their inhibitory rates decreased by the order of EGCG>GCG>ECG>EC. PL activity at first decreased rapidly and then slowly with the increase of EGCG analogs concentrations. α-Helix content of PL secondary structure decreased dependent on EGCG analogs concentration by the order of EGCG>GCG>ECG>EC. EGCG, ECG, and EC could quench PL fluorescence both dynamically and statically, while GCG only quenched statically. EGCG analogs would induce PL self-assembly into complexes and the hydrodynamic radii of the complexes possessed a close relationship with the inhibitory rates. Kinetics analysis showed that EGCG analogs non-competitively inhibited PL activity and did not bind to PL catalytic site. DSC measurement revealed that EGCG analogs decreased the transition midpoint temperature of PL enzyme, suggesting that these compounds reduced PL enzyme thermostability. In vitro renaturation through urea solution indicated that interactions between PL and EGCG analogs were weak and non-covalent.
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Affiliation(s)
- Shihui Wang
- Beijing Key Laboratory of Bioprocess, The Biorefinery Research and Engineering Center of the Ministry of Education of China, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Zeya Sun
- Beijing Key Laboratory of Bioprocess, The Biorefinery Research and Engineering Center of the Ministry of Education of China, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Shengzhao Dong
- Beijing Key Laboratory of Bioprocess, The Biorefinery Research and Engineering Center of the Ministry of Education of China, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yang Liu
- Beijing Key Laboratory of Bioprocess, The Biorefinery Research and Engineering Center of the Ministry of Education of China, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yun Liu
- Beijing Key Laboratory of Bioprocess, The Biorefinery Research and Engineering Center of the Ministry of Education of China, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
- * E-mail:
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121
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Caloric restriction mimetics: towards a molecular definition. Nat Rev Drug Discov 2014; 13:727-40. [PMID: 25212602 DOI: 10.1038/nrd4391] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Caloric restriction, be it constant or intermittent, is reputed to have health-promoting and lifespan-extending effects. Caloric restriction mimetics (CRMs) are compounds that mimic the biochemical and functional effects of caloric restriction. In this Opinion article, we propose a unifying definition of CRMs as compounds that stimulate autophagy by favouring the deacetylation of cellular proteins. This deacetylation process can be achieved by three classes of compounds that deplete acetyl coenzyme A (AcCoA; the sole donor of acetyl groups), that inhibit acetyl transferases (a group of enzymes that acetylate lysine residues in an array of proteins) or that stimulate the activity of deacetylases and hence reverse the action of acetyl transferases. A unifying definition of CRMs will be important for the continued development of this class of therapeutic agents.
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122
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Acharyya N, Chattopadhyay S, Maiti S. Chemoprevention against arsenic-induced mutagenic DNA breakage and apoptotic liver damage in rat via antioxidant and SOD1 upregulation by green tea (Camellia sinensis) which recovers broken DNA resulted from arsenic-H2O2 related in vitro oxidant stress. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2014; 32:338-361. [PMID: 25436473 DOI: 10.1080/10590501.2014.967061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Green tea (Camellia sinensis; CS) strongly reverses/prevents arsenic-induced apoptotic hepatic degeneration/micronecrosis and mutagenic DNA damage in in vitro oxidant stress model and in rat as shown by comet assay and histoarchitecture (HE and PAS staining) results. Earlier, we demonstrated a link between carcinogenesis and impaired antioxidant system-associated mutagenic DNA damage in arsenic-exposed human. In this study, arsenic-induced (0.6 ppm/100 g body weight/day for 28 days) impairment of cytosolic superoxide-dismutase (SOD1), catalase, xanthine-oxidase, thiol, and urate activities/levels led to increase in tissue levels of damaging malondialdehyde, conjugated dienes, serum necrotic-marker lactate-dehydrogenase, and metabolic inflammatory-marker c-reactive protein suggesting dysregulation at the transcriptional/signal-transduction level. These are decisively restrained by CS-extract (≥10 mg/ml aqueous) with a restoration of DNA/tissue structure. The structural/functional impairment of dialyzed and centrifugally concentrated (6-8 kd cutoff) hepatic SOD1 via its important Cys modifications by H2O2/arsenite redox-stress and that protection by CS/2-mercaptoethanol are shown in in vitro/in situ studies paralleling the present Swiss-Model-generated rSOD1 structural data. Here, arsenite(3+) incubation (≥10(-8) μM + 10 mM H2O2, 2 hr) is shown for the first time with this low-concentration to initiate breakage in rat hepatic-DNA in vitro whereas, arsenite/H2O2/UV-radiation does not affect DNA separately. Arsenic initiates Fe and Cu ion-associated free-radical reaction cascade in vivo. Here, 10 μM of Cu(2+)/Fe(3+)/As(3+) +H2O2-induced in vitro DNA fragmentation is prevented by CS (≥1 mg/ml), greater than the prevention of ascorbate or tocopherol or DMSO or their combination. Moreover, CS incubation for various time with differentially and already degraded DNA resulted from pre-incubation in 10 μM As(3+)-H2O2 system markedly recovers broken DNA. Present results decisively suggest for the first time that CS and its mixed polyphenols have potent SOD1 protecting, diverse radical-scavenging and antimutagenic activities furthering to DNA protection/therapy in arsenic-induced tissue necrosis/apoptosis.
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Affiliation(s)
- Nirmallya Acharyya
- a Post Graduate Department of Biochemistry and Biotechnology, Cell and Molecular Therapeutics Laboratory , Oriental Institute of Science and Technology, Vidyasagar University , Midnapore , West Bengal , India
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