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Ng TK, Chu KO, Wang CC, Pang CP. Green Tea Catechins as Therapeutic Antioxidants for Glaucoma Treatment. Antioxidants (Basel) 2023; 12:1320. [PMID: 37507860 PMCID: PMC10376590 DOI: 10.3390/antiox12071320] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/02/2023] [Accepted: 06/09/2023] [Indexed: 07/30/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness and visual impairment, affecting more than 80 million individuals worldwide. Oxidative stress and inflammation-induced neurodegenerative insults to retinal ganglion cells are the main pathogenesis of glaucoma. Retinal ganglion cells, the retinal neurons transmitting the visual signals to the visual cortex in the brain, have very limited regeneration or recovery capacity after damages. Apart from intraocular pressure-lowering treatments, there is still no clinically effective treatment to rescue the degeneration of retinal ganglion cells in glaucoma. Dietary antioxidants are easily accessible and can be applied as supplements assisting in the clinical treatments. Catechins, a chemical family of flavonoids, are the phenolic compounds found in many plants, especially in green tea. The anti-oxidative and anti-inflammatory properties of green tea catechins in vitro and in vivo have been well proven. They could be a potential treatment ameliorating retinal ganglion cell degeneration in glaucoma. In this review, the chemistry, pharmacokinetics, and therapeutic properties of green tea catechins were summarized. Research updates on the biological effects of green tea catechins in cellular and animal experimental glaucoma models were reviewed. In addition, clinical potentials of green tea catechins for glaucoma treatment were also highlighted.
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Affiliation(s)
- Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong
| | - Chi Pui Pang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
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2
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Yuan XL, Chen SL, Xu Y, Yao Y, Liang JJ, Zhuang X, Hald ES, Ng TK. Green tea extract enhances retinal ganglion cell survival and axonal regeneration in rats with optic nerve injury. J Nutr Biochem 2023; 117:109333. [PMID: 36965783 DOI: 10.1016/j.jnutbio.2023.109333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/11/2023] [Accepted: 03/18/2023] [Indexed: 03/27/2023]
Abstract
Current clinical treatments have not yet effectively cured progressive retinal ganglion cell (RGC) death and axonal degeneration after optic nerve (ON) injury. We previously demonstrated green tea extract (GTE) can reduce RGC death in rats after ischemic injury. Here, we aim to determine the prophylactic and therapeutic effects and mechanisms of GTE on RGC survival and axonal regeneration in rats with ON injury. GTE (275 or 550 mg/kg) was administered intragastrically for 7 d before or 14 d post-ON crush surgery in adult Fischer 344 rats. Rats with pre- or post-operative treatment of 275 mg/kg GTE showed significantly higher numbers of RGCs and regenerated axons post-ON injury with improved pupillary light reflex as compared to saline-treated rats. Akt and Erk p42/44 activation was higher in the retina of rats given 275 mg/kg GTE pre-surgery, whereas Stat3 activation was higher in those with 275 mg/kg GTE post-operation. Less activated microglia were observed in rats with pre-treatment of 275 or 550 mg/kg GTE. RNA sequencing analysis identified the downregulation of inflammation, apoptosis, and microglia activation genes in the retina of rats with pre- or post-treatment with 275 mg/kg GTE as compared to the saline-treated rats. In summary, this study revealed the prophylactic and therapeutic treatment effects of GTE on RGC survival and axonal regeneration in rats with ON injury, indicating a potential alternative treatment for traumatic optic neuropathy.
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Affiliation(s)
- Xiang-Ling Yuan
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China
| | - Shao-Lang Chen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Yanxuan Xu
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Yao Yao
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China
| | - Jia-Jian Liang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Xi Zhuang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Eric S Hald
- Department of Biomedical Engineering, Shantou University, Shantou, Guangdong, China
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
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3
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Elul T, Lim J, Hanton K, Lui A, Jones K, Chen G, Chong C, Dao S, Rawat R. Cannabinoid 1 Receptor CBIR regulates growth cone filopodia and axon dispersion in the optic tract of
Xenopus laevis
tadpoles. Eur J Neurosci 2022; 55:989-1001. [DOI: 10.1111/ejn.15603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 12/10/2021] [Accepted: 01/05/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Tamira Elul
- Touro University California Vallejo California US
| | - John Lim
- Touro University California Vallejo California US
| | | | - Austin Lui
- Touro University California Vallejo California US
| | - Kenton Jones
- Touro University California Vallejo California US
| | - George Chen
- Touro University California Vallejo California US
| | | | - Sophia Dao
- Touro University California Vallejo California US
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4
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Li J, Du L, He JN, Chu KO, Guo CL, Wong MOM, Pang CP, Chu WK. Anti-inflammatory Effects of GTE in Eye Diseases. Front Nutr 2021; 8:753955. [PMID: 34966770 PMCID: PMC8711650 DOI: 10.3389/fnut.2021.753955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ocular inflammation is a common complication of various eye diseases with wide consequences from irritations to potentially sight-threatening complications. Green tea is a popular beverage throughout the world. One of the proven health benefits of consuming green tea extract (GTE) is anti-inflammation. Catechins are the biologically active constituents of GTE. In in vitro and in vivo studies, GTE and catechins present inhibition of inflammatory responses in the development of ocular inflammation including infectious, non-infectious or autoimmune, and oxidative-induced complications. Research on the ocular inflammation in animal models has made significant progress in the past decades and several key disease mechanisms have been identified. Here we review the experimental investigations on the effects of GTE and catechins on various ocular inflammation related diseases including glaucoma, age-related macular degeneration, uveitis and ocular surface inflammation. We also review the pharmacokinetics of GTE constituents and safety of green tea consumption. We discuss the insights and perspectives of these experimental results, which would be useful for future development of novel therapeutics in human.
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Affiliation(s)
- Jian Li
- Department of Ophthalmology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Lin Du
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Jing Na He
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Cosmos Liutao Guo
- Bachelor of Medicine and Bachelor of Surgery Programme, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Mandy Oi Man Wong
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China.,Hong Kong Eye Hospital, Hong Kong, Hong Kong SAR, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
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5
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Gallemit PEM, Yoodee S, Malaitad T, Thongboonkerd V. Epigallocatechin-3-gallate plays more predominant roles than caffeine for inducing actin-crosslinking, ubiquitin/proteasome activity and glycolysis, and suppressing angiogenesis features of human endothelial cells. Biomed Pharmacother 2021; 141:111837. [PMID: 34175818 DOI: 10.1016/j.biopha.2021.111837] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/13/2021] [Accepted: 06/14/2021] [Indexed: 01/06/2023] Open
Abstract
A recent expression proteomics study has reported changes in cellular proteome (set of proteins) of human endothelial cells (ECs) induced by caffeine and epigallocatechin-3-gallate (EGCG), the most abundant bioactive compounds in coffee and green tea, respectively. Although both common and differential changes were highlighted by bioinformatics prediction, no experimental validation was performed. Herein, we reanalyzed these proteome datasets and performed protein-protein interactions network analysis followed by functional investigations using various assays to address the relevance of such proteome changes in human ECs functions. Protein-protein interactions network analysis revealed actin-crosslink formation, ubiquitin-proteasome activity and glycolysis as the three main networks among those significantly altered proteins induced by caffeine and EGCG. The experimental data showed predominant increases of actin-crosslink formation, ubiquitin-proteasome activity, and glycolysis (as reflected by increased F-actin and β-actin, declined ubiquitinated proteins and increased intracellular ATP, respectively) in the EGCG-treated cells. Investigations on angiogenesis features revealed that EGCG predominantly reduced ECs proliferation, migration/invasion, endothelial tube formation (as determined by numbers of nodes/junctions and meshes), barrier function (as determined by levels of VE-cadherin, zonula occludens-1 (ZO-1) and transendothelial resistance (TER)), and angiopoietin-2 secretion. However, both caffeine and EGCG had no effects on matrix metalloproteinase-2 (MMP-2) secretion. These data indicate that EGCG exhibits more potent effects on human ECs functions to induce actin-crosslink, ubiquitin-proteasome activity and glycolysis, and to suppress angiogenesis processes that commonly occur in various diseases, particularly cancers.
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Affiliation(s)
| | - Sunisa Yoodee
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Thanyalak Malaitad
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
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6
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Unno K, Pervin M, Taguchi K, Konishi T, Nakamura Y. Green Tea Catechins Trigger Immediate-Early Genes in the Hippocampus and Prevent Cognitive Decline and Lifespan Shortening. Molecules 2020; 25:molecules25071484. [PMID: 32218277 PMCID: PMC7181211 DOI: 10.3390/molecules25071484] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/21/2020] [Accepted: 03/23/2020] [Indexed: 12/14/2022] Open
Abstract
Senescence-accelerated mouse prone 10 (SAMP10) mice, after ingesting green tea catechins (GT-catechin, 60 mg/kg), were found to have suppressed aging-related decline in brain function. The dose dependence of brain function on GT-catechin indicated that intake of 1 mg/kg or more suppressed cognitive decline and a shortened lifespan. Mice that ingested 1 mg/kg GT-catechin had the longest median survival, but the dose was less effective at suppressing cognitive decline. The optimal dose for improving memory acquisition was 60 mg/kg, and memory retention was higher in mice that ingested 30 mg/kg or more. To elucidate the mechanism by which cognitive decline is suppressed by GT-catechin, changes in gene expression in the hippocampus of SAMP10 mice one month after ingesting GT-catechin were analyzed. The results show that the expression of immediate-early genes such as nuclear receptor subfamily 4 (Nr4a), FBJ osteosarcoma oncogene (Fos), early growth response 1 (Egr1), neuronal PAS domain protein 4 (Npas4), and cysteine-rich protein 61 (Cyr61) was significantly increased. These results suggest that GT-catechin suppresses age-related cognitive decline via increased expression of immediate-early genes that are involved in long-term changes in plasticity of synapses and neuronal circuits.
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Affiliation(s)
- Keiko Unno
- Tea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan; (M.P.); (K.T.); (Y.N.)
- Correspondence: ; Tel.: +81-54-264-5822
| | - Monira Pervin
- Tea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan; (M.P.); (K.T.); (Y.N.)
| | - Kyoko Taguchi
- Tea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan; (M.P.); (K.T.); (Y.N.)
| | - Tomokazu Konishi
- Faculty of Bioresources Sciences, Akita Prefectural University, Shimoshinjo Nakano, Akita 010-0195, Japan;
| | - Yoriyuki Nakamura
- Tea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan; (M.P.); (K.T.); (Y.N.)
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7
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Estrogenic biological activity and underlying molecular mechanisms of green tea constituents. Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2019.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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8
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Cagnetta R, Frese CK, Shigeoka T, Krijgsveld J, Holt CE. Rapid Cue-Specific Remodeling of the Nascent Axonal Proteome. Neuron 2018; 99:29-46.e4. [PMID: 30008298 PMCID: PMC6048689 DOI: 10.1016/j.neuron.2018.06.004] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/24/2017] [Accepted: 05/31/2018] [Indexed: 01/13/2023]
Abstract
Axonal protein synthesis and degradation are rapidly regulated by extrinsic signals during neural wiring, but the full landscape of proteomic changes remains unknown due to limitations in axon sampling and sensitivity. By combining pulsed stable isotope labeling of amino acids in cell culture with single-pot solid-phase-enhanced sample preparation, we characterized the nascent proteome of isolated retinal axons on an unparalleled rapid timescale (5 min). Our analysis detects 350 basally translated axonal proteins on average, including several linked to neurological disease. Axons stimulated by different cues (Netrin-1, BDNF, Sema3A) show distinct signatures with more than 100 different nascent protein species up- or downregulated within the first 5 min followed by further dynamic remodeling. Switching repulsion to attraction triggers opposite regulation of a subset of common nascent proteins. Our findings thus reveal the rapid remodeling of the axonal proteomic landscape by extrinsic cues and uncover a logic underlying attraction versus repulsion.
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Affiliation(s)
- Roberta Cagnetta
- Department of Physiology Development and Neuroscience, Downing Street, University of Cambridge, Cambridge CB2 3DY, UK
| | - Christian K Frese
- European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, Heidelberg 69117, Germany; German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, Heidelberg 69120, Germany; CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, Cologne 50931, Germany
| | - Toshiaki Shigeoka
- Department of Physiology Development and Neuroscience, Downing Street, University of Cambridge, Cambridge CB2 3DY, UK
| | - Jeroen Krijgsveld
- European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, Heidelberg 69117, Germany; German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, Heidelberg 69120, Germany; Excellence Cluster CellNetworks, University of Heidelberg, Im Neuenheimer Feld 581, Heidelberg 69120, Germany.
| | - Christine E Holt
- Department of Physiology Development and Neuroscience, Downing Street, University of Cambridge, Cambridge CB2 3DY, UK.
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9
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Urbančič V, Butler R, Richier B, Peter M, Mason J, Livesey FJ, Holt CE, Gallop JL. Filopodyan: An open-source pipeline for the analysis of filopodia. J Cell Biol 2017; 216:3405-3422. [PMID: 28760769 PMCID: PMC5626553 DOI: 10.1083/jcb.201705113] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/28/2017] [Accepted: 07/06/2017] [Indexed: 02/07/2023] Open
Abstract
Filopodia have important sensory and mechanical roles in motile cells. The recruitment of actin regulators, such as ENA/VASP proteins, to sites of protrusion underlies diverse molecular mechanisms of filopodia formation and extension. We developed Filopodyan (filopodia dynamics analysis) in Fiji and R to measure fluorescence in filopodia and at their tips and bases concurrently with their morphological and dynamic properties. Filopodyan supports high-throughput phenotype characterization as well as detailed interactive editing of filopodia reconstructions through an intuitive graphical user interface. Our highly customizable pipeline is widely applicable, capable of detecting filopodia in four different cell types in vitro and in vivo. We use Filopodyan to quantify the recruitment of ENA and VASP preceding filopodia formation in neuronal growth cones, and uncover a molecular heterogeneity whereby different filopodia display markedly different responses to changes in the accumulation of ENA and VASP fluorescence in their tips over time.
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Affiliation(s)
- Vasja Urbančič
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Richard Butler
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
| | - Benjamin Richier
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Manuel Peter
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Julia Mason
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Frederick J Livesey
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Christine E Holt
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, England, UK
| | - Jennifer L Gallop
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
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10
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Guo X, Liu X. Nogo receptor knockdown and ciliary neurotrophic factor attenuate diabetic retinopathy in streptozotocin-induced diabetic rats. Mol Med Rep 2017; 16:2030-2036. [PMID: 28656312 PMCID: PMC5562098 DOI: 10.3892/mmr.2017.6850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 06/08/2017] [Indexed: 12/14/2022] Open
Abstract
Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM). We investigated whether Nogo receptor (NgR) knockdown and ciliary neurotrophic factor (CNTF) treatment, either alone or in combination, ameliorated diabetic retinopathy (DR) in diabetic rat model. STZ‑induced diabetic rats were administrated for a total of 12 weeks with 3 µM siRNA (5 µl) once every 6 weeks and/or 1 µg CNTF weekly. The retinal tissues were excised. We measured cell number in ganglion cell layer (GCL) using H&E staining and cell apoptosis using TUNEL assay. Bax, Bcl‑2, Caspase‑3, F‑actin, GAP‑43, NgR, RhoA and Rock1 levels were then analyzed by Western blotting, Immunohistochemistry or Real‑time PCR. We found that NgR siRNA or CNTF injection alone significantly increased cell count in GCL in diabetic rats, inhibited ganglion cell apoptosis, elevated Bcl‑2, F‑actin and GAP‑43, and decreased Bax, Caspase‑3, NgR, RhoA and Rock1 levels. Combination treatment further prevented retinal ganglion cell loss, enhanced growth cone cytoskeleton and axonal regeneration, and suppressed NgR/RhoA/Rock1. Our results indicate that combination therapy has therapeutic potential for the treatment of DR.
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Affiliation(s)
- Xiliang Guo
- Department of Human Anatomy, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
- Department of Anatomy, School of Basic Medical Sciences, Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Xuezheng Liu
- Department of Human Anatomy, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
- Department of Anatomy, School of Basic Medical Sciences, Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
- Correspondence to: Dr Xuezheng Liu, Department of Human Anatomy, School of Basic Medical Sciences, Guangxi Medical University, 22 Shuangyong Road, Nanning, Guangxi 530021, P.R. China, E-mail:
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11
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Abstract
Protein function can be regulated via post-translational modifications by numerous enzymatic and non-enzymatic mechanisms, including oxidation of cysteine and methionine residues. Redox-dependent regulatory mechanisms have been identified for nearly every cellular process, but the major paradigm has been that cellular components are oxidized (damaged) by reactive oxygen species (ROS) in a relatively unspecific way, and then reduced (repaired) by designated reductases. While this scheme may work with cysteine, it cannot be ascribed to other residues, such as methionine, whose reaction with ROS is too slow to be biologically relevant. However, methionine is clearly oxidized in vivo and enzymes for its stereoselective reduction are present in all three domains of life. Here, we revisit the chemistry and biology of methionine oxidation, with emphasis on its generation by enzymes from the monooxygenase family. Particular attention is placed on MICALs, a recently discovered family of proteins that harbor an unusual flavin-monooxygenase domain with an NADPH-dependent methionine sulfoxidase activity. Based on structural and kinetic information we provide a rational framework to explain MICAL mechanism, inhibition, and regulation. Methionine residues that are targeted by MICALs are reduced back by methionine sulfoxide reductases, suggesting that reversible methionine oxidation may be a general mechanism analogous to the regulation by phosphorylation by kinases/phosphatases. The identification of new enzymes that catalyze the oxidation of methionine will open a new area of research at the forefront of redox signaling.
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Affiliation(s)
- Bruno Manta
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Vadim N Gladyshev
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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12
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Vanoni MA. Structure-function studies of MICAL, the unusual multidomain flavoenzyme involved in actin cytoskeleton dynamics. Arch Biochem Biophys 2017; 632:118-141. [PMID: 28602956 DOI: 10.1016/j.abb.2017.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 05/27/2017] [Accepted: 06/05/2017] [Indexed: 12/11/2022]
Abstract
MICAL (from the Molecule Interacting with CasL) indicates a family of multidomain proteins conserved from insects to humans, which are increasingly attracting attention for their participation in the control of actin cytoskeleton dynamics, and, therefore, in the several related key processes in health and disease. MICAL is unique among actin binding proteins because it catalyzes a NADPH-dependent F-actin depolymerizing reaction. This unprecedented reaction is associated with its N-terminal FAD-containing domain that is structurally related to p-hydroxybenzoate hydroxylase, the prototype of aromatic monooxygenases, but catalyzes a strong NADPH oxidase activity in the free state. This review will focus on the known structural and functional properties of MICAL forms in order to provide an overview of the arguments supporting the current hypotheses on the possible mechanism of action of MICAL in the free and F-actin bound state, on the modulating effect of the CH, LIM, and C-terminal domains that follow the catalytic flavoprotein domain on the MICAL activities, as well as that of small molecules and proteins interacting with MICAL.
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Affiliation(s)
- Maria Antonietta Vanoni
- Department of Biosciences, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
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13
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Wu BK, Yuan RY, Chang YP, Lien HW, Chen TS, Chien HC, Tong TS, Tsai HP, Fang CL, Liao YF, Chang CC, Chen RPY, Huang CJ. Epicatechin isolated from Tripterygium wilfordii extract reduces tau-GFP-induced neurotoxicity in zebrafish embryo through the activation of Nrf2. Biochem Biophys Res Commun 2016; 477:283-9. [PMID: 27301640 DOI: 10.1016/j.bbrc.2016.06.058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 11/15/2022]
Abstract
Tau plays important roles in the assembly and stabilization of the microtubule structure to facilitate axonal transport in mammalian brain. The intracellular tau aggregates to form paired helical filaments leading to neurodegenerative disorders, collectively called tauopathies. In our previous report, we established a zebrafish model to express tau-GFP to induce neuronal death, which could be directly traced in vivo. Recently, we used this model to screen 400 herbal extracts and found 45 of them to be effective on reducing tau-GFP-induced neuronal death. One of the effective herbal extracts is the Tripterygium wilfordii stem extract. HPLC analysis and functional assay demonstrated that epicatechin (EC) is the major compound of Tripterygium wilfordii stem extract to decrease the neurotoxicity induced by tau-GFP. Using a luciferase reporter assay in the zebrafish, we confirmed that EC could activate Nrf2-dependent antioxidant responses to significantly increase the ARE-controlled expression of luciferase reporter gene. These data suggest that EC from the Tripterygium wilfordii stem extract could diminish tau-GFP-induced neuronal death through the activation of Nrf2.
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Affiliation(s)
- Bo-Kai Wu
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan; Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Rey-Yue Yuan
- Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Yen-Pu Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Huang-Wei Lien
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Ting-Shou Chen
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan
| | - Hung-Chi Chien
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan
| | - Tien-Soung Tong
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan
| | - Hui-Ping Tsai
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan
| | - Cheng-Li Fang
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan
| | - Yung-Feng Liao
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Chun-Che Chang
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan; Department of Entomology, National Taiwan University, Taipei 106, Taiwan.
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
| | - Chang-Jen Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
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