1
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Wang CY, Yang CC, Hsiao LD, Yang CM. Involvement of FoxO1, Sp1, and Nrf2 in Upregulation of Negative Regulator of ROS by 15d-PGJ 2 Attenuates H 2O 2-Induced IL-6 Expression in Rat Brain Astrocytes. Neurotox Res 2022; 40:154-172. [PMID: 34997457 PMCID: PMC8784370 DOI: 10.1007/s12640-020-00318-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 02/08/2023]
Abstract
Excessive production of reactive oxygen species (ROS) by NADPH oxidase (Nox) resulted in inflammation. The negative regulator of ROS (NRROS) dampens ROS generation during inflammatory responses. 15-Deoxy-∆12,14-prostaglandin J2 (15d-PGJ2) exhibits neuroprotective effects on central nervous system (CNS). However, whether 15d-PGJ2-induced NRROS expression was unknown in rat brain astrocytes (RBA-1). NRROS expression was determined by Western blot, RT/real-time PCR, and promoter activity assays. The signaling components were investigated using pharmacological inhibitors or specific siRNAs. The interaction between transcription factors and the NRROS promoter was investigated by chromatin immunoprecipitation assay. Upregulation of NRROS on the hydrogen peroxide (H2O2)-mediated ROS generation and interleukin 6 (IL-6) secretion was measured. 15d-PGJ2-induced NRROS expression was mediated through PI3K/Akt-dependent activation of Sp1 and FoxO1 and established the essential promoter regions. We demonstrated that 15d-PGJ2 activated PI3K/Akt and following by cooperation between phosphorylated nuclear FoxO1 and Sp1 to initiate the NRROS transcription. In addition, Nrf2 played a key role in NRROS expression induced by 15d-PGJ2 which was mediated through its phosphorylation. Finally, the NRROS stable clones attenuated the H2O2-induced ROS generation and expression of IL-6 through suppressing the Nox-2 activity. These results suggested that 15d-PGJ2-induced NRROS expression is mediated through a PI3K/Akt-dependent FoxO1 and Sp1 phosphorylation, and Nrf2 cascade, which suppresses ROS generation through attenuating the p47phox phosphorylation and gp91phox formation and IL-6 expression in RBA-1 cells. These results confirmed the mechanisms underlying 15d-PGJ2-induced NRROS expression which might be a potential strategy for prevention and management of brain inflammatory and neurodegenerative diseases.
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Affiliation(s)
- Chen-Yu Wang
- Department of Pharmacology, College of Medicine, China Medical University, Taichung, 40402, Taiwan
| | - Chien-Chung Yang
- Department of Traditional Chinese Medicine, Chang Gung Memorial Hospital At Tao-Yuan, Kwei-San, Tao-Yuan, 33302, Taiwan.,School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, 33302, Taiwan
| | - Li-Der Hsiao
- Department of Pharmacology, College of Medicine, China Medical University, Taichung, 40402, Taiwan
| | - Chuen-Mao Yang
- Department of Pharmacology, College of Medicine, China Medical University, Taichung, 40402, Taiwan. .,Ph.D. Program for Biotch Pharmaceutical Industry, China Medical University, Taichung, 40402, Taiwan. .,Department of Post-Baccalaureate Veterinary Medicine, College of Medical and Health Science, Asia University, Wufeng, Taichung, 41354, Taiwan.
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2
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Kao MH, Wu JS, Cheung WM, Chen JJ, Sun GY, Ong WY, Herr DR, Lin TN. Clinacanthus nutans Mitigates Neuronal Death and Reduces Ischemic Brain Injury: Role of NF-κB-driven IL-1β Transcription. Neuromolecular Med 2020; 23:199-210. [PMID: 33025396 DOI: 10.1007/s12017-020-08618-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 09/26/2020] [Indexed: 12/15/2022]
Abstract
Neuroinflammation has been shown to exacerbate ischemic brain injury, and is considered as a prime target for the development of stroke therapies. Clinacanthus nutans Lindau (C. nutans) is widely used in traditional medicine for treating insect bites, viral infection and cancer, due largely to its anti-oxidative and anti-inflammatory properties. Recently, we reported that an ethanol extract from the leaf of C. nutans could protect the brain against ischemia-triggered neuronal death and infarction. In order to further understand the molecular mechanism(s) for its beneficial effects, two experimental paradigms, namely, in vitro primary cortical neurons subjected to oxygen-glucose deprivation (OGD) and in vivo rat middle cerebral artery (MCA) occlusion, were used to dissect the anti-inflammatory effects of C. nutans extract. Using promoter assays, immunofluorescence staining, and loss-of-function (siRNA) approaches, we demonstrated that transient OGD led to marked induction of IL-1β, IL-6 and TNFα, while pretreatment with C. nutans suppressed production of inflammatory cytokines in primary neurons. C. nutans inhibited IL-1β transcription via preventing NF-κB/p65 nuclear translocation, and siRNA knockdown of either p65 or IL-1β mitigated OGD-mediated neuronal death. Correspondingly, post-ischemic treatment of C. nutans attenuated IκBα degradation and decreased IL-1β, IL-6 and TNFα production in the ischemic brain. Furthermore, IL-1β siRNA post-ischemic treatment reduced cerebral infarct, thus mimicking the beneficial effects of C. nutans. In summary, our findings demonstrated the ability for C. nutans to suppress NF-κB nuclear translocation and inhibit IL-1β transcription in ischemic models. Results further suggest the possibility for using C. nutans to prevent and treat stroke patients.
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Affiliation(s)
- Mei-Han Kao
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Jui-Sheng Wu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, ROC
| | - Wai-Mui Cheung
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, ROC
| | - Jin-Jer Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, ROC
| | - Grace Y Sun
- Department of Biochemistry, University of Missouri, Columbia, USA
| | - Wei-Yi Ong
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, 119260, Singapore
| | - Deron R Herr
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119260, Singapore
| | - Teng-Nan Lin
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan. .,Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, ROC.
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3
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Morris G, Puri BK, Maes M, Olive L, Berk M, Carvalho AF. The role of microglia in neuroprogressive disorders: mechanisms and possible neurotherapeutic effects of induced ketosis. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109858. [PMID: 31923453 DOI: 10.1016/j.pnpbp.2020.109858] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 12/23/2022]
Abstract
A comprehensive review of molecular mechanisms involved in the promotion and maintenance of distinct microglia phenotypes is provided. The acquisition and perpetuation of predominantly pro-inflammatory microglial phenotypes have been implicated in the pathophysiology of several neuroprogressive diseases and is associated with reduced ATP production via oxidative phosphorylation, increased ATP generation by glycolysis, elevated oxidative and nitrosative stress and other metabolic, inflammatory and hormonal insults. Microglia can also adopt a predominantly anti-inflammatory phenotypes with neuroprotective properties. Strategies that promote and maintain a predominantly anti-inflammatory phenotype may hold promise as novel therapeutic opportunities for neuroprogressive illness. Induced ketosis may promote a transition towards predominantly anti-inflammatory microglial states/phenotypes by several mechanisms, including inhibition of glycolysis and increased NAD+ production; engagement of microglial GPR109A receptors; histone deacetylase inhibition; and elevated n-3 polyunsaturated fatty acids levels. Since microglia activation can now be assessed in vivo, these data provide a clear rationale for the design of transdiagnostic randomized controlled trials of the ketogenic diet and other ketosis-inducing strategies for neuroprogressive diseases, which may also provide mechanistic insights through the assessment of "target engagement".
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | | | - Michael Maes
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Lisa Olive
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Michael Berk
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia; Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andre F Carvalho
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.
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4
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15-Deoxy-∆- 12,14-Prostaglandin J2 (15d-PGJ2), an Endogenous Ligand of PPAR- γ: Function and Mechanism. PPAR Res 2019; 2019:7242030. [PMID: 31467514 PMCID: PMC6699332 DOI: 10.1155/2019/7242030] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/14/2019] [Indexed: 02/06/2023] Open
Abstract
15-Deoxy-∆-12,14-prostaglandin J2 (15d-PGJ2), a natural peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, has been explored in some detail over the last 20 years. By triggering the PPAR-γ signalling pathway, it plays many roles and exerts antitumour, anti-inflammatory, antioxidation, antifibrosis, and antiangiogenesis effects. Although many synthetic PPAR-γ receptor agonists have been developed, as an endogenous product of PPAR-γ receptors, 15d-PGJ2 has beneficial characteristics including rapid expression and the ability to contribute to a natural defence mechanism. In this review, we discuss the latest advances in our knowledge of the biological role of 15d-PGJ2 mediated through PPAR-γ. It is important to understand its structure, synthesis, and functional mechanisms to develop preventive agents and limit the progression of associated diseases.
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5
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Seiri P, Abi A, Soukhtanloo M. PPAR-γ: Its ligand and its regulation by microRNAs. J Cell Biochem 2019; 120:10893-10908. [PMID: 30770587 DOI: 10.1002/jcb.28419] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 12/04/2018] [Indexed: 01/24/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear receptor superfamily. PPARs are categorized into three subtypes, PPARα, β/δ, and γ, encoded by different genes, expressed in diverse tissues and participate in various biological functions and can be activated by their metabolic derivatives in the body or dietary fatty acids. The PPAR-γ also takes parts in the regulation of energy balance, lipoprotein metabolism, insulin sensitivity, oxidative stress, and inflammatory signaling. It has been implicated in the pathology of numerous diseases including obesity, diabetes, atherosclerosis, and cancers. Among various cellular and molecular targets that are able to regulate PPAR-γ and its underlying pathways, microRNAs (miRNAs) appeared as important regulators. Given that the deregulation of these molecules via targeting PPAR-γ could affect initiation and progression of various diseases, identification of miRNAs that affects PPAR-γ could contribute to the better understanding of roles of PPAR-γ in various biological and pathological conditions. Here, we have summarized the function and various ligands of PPAR-γ and have highlighted various miRNAs involved in the regulation of PPAR-γ.
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Affiliation(s)
- Parvaneh Seiri
- Department of Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abbas Abi
- Department of Biotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Soukhtanloo
- Department of Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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6
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Giampietro L, Gallorini M, De Filippis B, Amoroso R, Cataldi A, di Giacomo V. PPAR-γ agonist GL516 reduces oxidative stress and apoptosis occurrence in a rat astrocyte cell line. Neurochem Int 2019; 126:239-245. [PMID: 30946848 DOI: 10.1016/j.neuint.2019.03.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 03/19/2019] [Accepted: 03/27/2019] [Indexed: 01/11/2023]
Abstract
AIMS The worldwide increase in aging population is prevalently associated with the increase of neurodegenerative diseases. Peroxisome Proliferator-Activated Receptors (PPARs) are ligand-modulated transcriptional factors which belong to the nuclear hormone receptor superfamily which regulates peroxisome proliferation. The PPAR-γ is the most extensively studied among the three isoforms and the neuroprotective effects of PPAR-γ agonists have been recently demonstrated in a variety of preclinical models of neurological disorders. The aim of the study is to biologically evaluate the neuroprotective effects of new PPAR-γ selective agonists in an in vitro model. MAIN METHODS CTX-TNA2 rat astrocytes were treated with G3335, a PPAR-γ antagonist, to simulate the conditions of a neurological disorder. Newly synthetized PPAR-γ selective agonists were added to the cell culture. Cytotoxicity was assessed by MTT assay, catalase activity was investigated by a colorimetric assay, Reactive Oxygen Species (ROS) production and apoptosis occurrence were measured by flow cytometry. Western blotting were performed to measure the levels of protein involved in the apoptotic pathway. KEY FINDINGS Four PPAR-γ agonists were selected. Among them, the GL516, a fibrate derivative, showed low cytotoxicity and proved effective in restoring the catalase activity, reducing ROS production and decreasing the apoptosis occurrence triggered by the G3335 administration. The effects of this molecule appear to be comparable to the reference compound rosiglitazone, a potent and selective PPAR-γ agonist, mainly at prolonged exposure times (96 h). SIGNIFICANCE Based on recent evidence, hypofunctionality of the PPAR-γ in glial cells could be present in neurodegenerative diseases and could participate in pathological mechanisms through peroxisomal damage. The fibrate derivative PPAR-γ agonist GL516 emerged as the most promising molecule of the series and could have a role in preventing the pathophysiology of neurodegenerative disorders.
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Affiliation(s)
- Letizia Giampietro
- Department of Pharmacy, University G. d'Annunzio, Chieti-Pescara, via dei Vestini 31, Chieti Scalo, Italy
| | - Marialucia Gallorini
- Department of Pharmacy, University G. d'Annunzio, Chieti-Pescara, via dei Vestini 31, Chieti Scalo, Italy.
| | - Barbara De Filippis
- Department of Pharmacy, University G. d'Annunzio, Chieti-Pescara, via dei Vestini 31, Chieti Scalo, Italy
| | - Rosa Amoroso
- Department of Pharmacy, University G. d'Annunzio, Chieti-Pescara, via dei Vestini 31, Chieti Scalo, Italy
| | - Amelia Cataldi
- Department of Pharmacy, University G. d'Annunzio, Chieti-Pescara, via dei Vestini 31, Chieti Scalo, Italy
| | - Viviana di Giacomo
- Department of Pharmacy, University G. d'Annunzio, Chieti-Pescara, via dei Vestini 31, Chieti Scalo, Italy
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7
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Wu JS, Kao MH, Tsai HD, Cheung WM, Chen JJ, Ong WY, Sun GY, Lin TN. Clinacanthus nutans Mitigates Neuronal Apoptosis and Ischemic Brain Damage Through Augmenting the C/EBPβ-Driven PPAR-γ Transcription. Mol Neurobiol 2017; 55:5425-5438. [PMID: 28942553 DOI: 10.1007/s12035-017-0776-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023]
Abstract
Clinacanthus nutans Lindau (C. nutans) is a traditional herbal medicine widely used in Asian countries for treating a number of remedies including snake and insect bites, skin rashes, viral infections, and cancer. However, the underlying molecular mechanisms for its action and whether C. nutans can offer protection on stroke damage in brain remain largely unknown. In the present study, we demonstrated protective effects of C. nutans extract to ameliorate neuronal apoptotic death in the oxygen-glucose deprivation model and to reduce infarction and mitigate functional deficits in the middle cerebral artery occlusion model, either administered before or after hypoxic/ischemic insult. Using pharmacological antagonist and siRNA knockdown approaches, we demonstrated ability for C. nutans extract to protect neurons and ameliorate ischemic injury through promoting the anti-apoptotic activity of peroxisome proliferator-activated receptor-gamma (PPAR-γ), a stress-induced transcription factor. Reporter and chromatin immunoprecipitation promoter analysis further revealed C. nutans extract to selectively increase CCAAT/enhancer binding protein (C/EBP)β binding to specific C/EBP binding site (-332~-325) on the PPAR-γ promoter to augment its transcription. In summary, we report a novel transcriptional activation involving C/EBPβ upregulation of PPAR-γ expression to suppress ischemic neuronal apoptosis and brain infarct. Recognition of C. nutans to enhance the C/EBPβ → PPAR-γ neuroprotective signaling pathway paves a new way for future drug development for prevention and treatment of ischemic stroke and other neurodegenerative diseases.
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Affiliation(s)
- Jui-Sheng Wu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, Republic of China
| | - Mei-Han Kao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, Republic of China
| | - Hsin-Da Tsai
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, Republic of China
| | - Wai-Mui Cheung
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, Republic of China
| | - Jin-Jer Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, Republic of China
| | - Wei-Yi Ong
- Department of Anatomy, National University of Singapore, Singapore, Singapore
| | - Grace Y Sun
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Teng-Nan Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan, Republic of China. .,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Republic of China.
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8
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Physiological and Pathological Roles of 15-Deoxy-Δ12,14-Prostaglandin J2 in the Central Nervous System and Neurological Diseases. Mol Neurobiol 2017; 55:2227-2248. [DOI: 10.1007/s12035-017-0435-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 02/03/2017] [Indexed: 12/29/2022]
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9
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Shan H, Zhang S, Wei X, Li X, Qi H, He Y, Liu A, Luo D, Yu X. Protection of endothelial cells against Ang II-induced impairment: Involvement of both PPARα and PPARγ via PI3K/Akt pathway. Clin Exp Hypertens 2016; 38:571-577. [PMID: 27650941 DOI: 10.3109/10641963.2016.1174248] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- HaiYan Shan
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Siyang Zhang
- Science Experiment Center, China Medical University, Shenyang, China
| | - Xiaojie Wei
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xuelian Li
- Department of Epidemiology, College of Public Health China Medical University, Shenyang, China
| | - Huimeng Qi
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yini He
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Ao Liu
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Donghui Luo
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xiaosong Yu
- Department of General Practice, The First Affiliated Hospital of China Medical University, Shenyang, China
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10
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Clinacanthus nutans Extracts Modulate Epigenetic Link to Cytosolic Phospholipase A2 Expression in SH-SY5Y Cells and Primary Cortical Neurons. Neuromolecular Med 2016; 18:441-52. [PMID: 27319010 DOI: 10.1007/s12017-016-8404-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
Abstract
Clinacanthus nutans Lindau (C. nutans), commonly known as Sabah Snake Grass in southeast Asia, is widely used in folk medicine due to its analgesic, antiviral, and anti-inflammatory properties. Our recent study provided evidence for the regulation of cytosolic phospholipase A2 (cPLA2) mRNA expression by epigenetic factors (Tan et al. in Mol Neurobiol. doi: 10.1007/s12035-015-9314-z , 2015). This enzyme catalyzes the release of arachidonic acid from glycerophospholipids, and formation of pro-inflammatory eicosanoids or toxic lipid peroxidation products such as 4-hydroxynonenal. In this study, we examined the effects of C. nutans ethanol leaf extracts on epigenetic regulation of cPLA2 mRNA expression in SH-SY5Y human neuroblastoma cells and mouse primary cortical neurons. C. nutans modulated induction of cPLA2 expression in SH-SY5Y cells by histone deacetylase (HDAC) inhibitors, MS-275, MC-1568, and TSA. C. nutans extracts also inhibited histone acetylase (HAT) activity. Levels of cPLA2 mRNA expression were increased in primary cortical neurons subjected to 0.5-h oxygen-glucose deprivation injury (OGD). This increase was significantly inhibited by C. nutans treatment. Treatment of primary neurons with the HDAC inhibitor MS-275 augmented OGD-induced cPLA2 mRNA expression, and this increase was modulated by C. nutans extracts. OGD-stimulated increase in cPLA2 mRNA expression was also reduced by a Tip60 HAT inhibitor, NU9056. In view of a key role of cPLA2 in the production of pro-inflammatory eicosanoids and free radical damage, and the fact that epigenetic effects on genes are often long-lasting, results suggest a role for C. nutans and phytochemicals to inhibit the production of arachidonic acid-derived pro-inflammatory eicosanoids and chronic inflammation, through epigenetic regulation of cPLA2 expression.
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11
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Clinacanthus nutans Protects Cortical Neurons Against Hypoxia-Induced Toxicity by Downregulating HDAC1/6. Neuromolecular Med 2016; 18:274-82. [PMID: 27165113 DOI: 10.1007/s12017-016-8401-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
Many population-based epidemiological studies have unveiled an inverse correlation between intake of herbal plants and incidence of stroke. C. nutans is a traditional herbal medicine widely used for snake bite, viral infection and cancer in Asian countries. However, its role in protecting stroke damage remains to be studied. Despite of growing evidence to support epigenetic regulation in the pathogenesis and recovery of stroke, a clear understanding of the underlying molecular mechanisms is still lacking. In the present study, primary cortical neurons were subjected to in vitro oxygen-glucose deprivation (OGD)-reoxygenation and hypoxic neuronal death was used to investigate the interaction between C. nutans and histone deacetylases (HDACs). Using pharmacological agents (HDAC inhibitor/activator), loss-of-function (HDAC siRNA) and gain-of-function (HDAC plasmid) approaches, we demonstrated an early induction of HDAC1/2/3/8 and HDAC6 in neurons after OGD insult. C. nutans extract selectively inhibited HDAC1 and HDAC6 expression and attenuated neuronal death. Results of reporter analysis further revealed that C. nutans suppressed HDAC1 and HDAC6 transcription. Besides ameliorating neuronal death, C. nutans also protected astrocytes and endothelial cells from hypoxic-induced cell death. In summary, results support ability for C. nutans to suppress post-hypoxic HDACs activation and mitigate against OGD-induced neuronal death. This study further opens a new avenue for the use of herbal medicines to regulate epigenetic control of brain injury.
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12
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Wu JS, Tsai HD, Cheung WM, Hsu CY, Lin TN. PPAR-γ Ameliorates Neuronal Apoptosis and Ischemic Brain Injury via Suppressing NF-κB-Driven p22phox Transcription. Mol Neurobiol 2015; 53:3626-3645. [PMID: 26108185 DOI: 10.1007/s12035-015-9294-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/08/2015] [Indexed: 12/14/2022]
Abstract
Peroxisome proliferator-activated receptor-gamma (PPAR-γ), a stress-induced transcription factor, protects neurons against ischemic stroke insult by reducing oxidative stress. NADPH oxidase (NOX) activation, a major driving force in ROS generation in the setting of reoxygenation/reperfusion, constitutes an important pathogenetic mechanism of ischemic brain damage. In the present study, both transient in vitro oxygen-glucose deprivation and in vivo middle cerebral artery (MCA) occlusion-reperfusion experimental paradigms of ischemic neuronal death were used to investigate the interaction between PPAR-γ and NOX. With pharmacological (PPAR-γ antagonist GW9662), loss-of-function (PPAR-γ siRNA), and gain-of-function (Ad-PPAR-γ) approaches, we first demonstrated that 15-deoxy-∆(12,14)-PGJ2 (15d-PGJ2), via selectively attenuating p22phox expression, inhibited NOX activation and the subsequent ROS generation and neuronal death in a PPAR-γ-dependent manner. Secondly, results of promoter analyses and subcellular localization studies further revealed that PPAR-γ, via inhibiting hypoxia-induced NF-κB nuclear translocation, indirectly suppressed NF-κB-driven p22phox transcription. Noteworthily, postischemic p22phox siRNA treatment not only reduced infarct volumes but also improved functional outcome. In summary, we report a novel transrepression mechanism involving PPAR-γ downregulation of p22phox expression to suppress the subsequent NOX activation, ischemic neuronal death, and brain infarct. Identification of a PPAR-γ → NF-κB → p22phox neuroprotective signaling cascade opens a new avenue for protecting the brain against ischemic insult.
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Affiliation(s)
- Jui-Sheng Wu
- Institute of Biomedical Sciences, Academia Sinica, Rm 404, Taipei, 11529, Taiwan, Republic of China
| | - Hsin-Da Tsai
- Institute of Biomedical Sciences, Academia Sinica, Rm 404, Taipei, 11529, Taiwan, Republic of China
| | - Wai-Mui Cheung
- Institute of Biomedical Sciences, Academia Sinica, Rm 404, Taipei, 11529, Taiwan, Republic of China
| | - Chung Y Hsu
- Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Teng-Nan Lin
- Institute of Biomedical Sciences, Academia Sinica, Rm 404, Taipei, 11529, Taiwan, Republic of China. .,Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan. .,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
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13
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Huang CY, Chen JJ, Wu JS, Tsai HD, Lin H, Yan YT, Hsu CY, Ho YS, Lin TN. Novel link of anti-apoptotic ATF3 with pro-apoptotic CTMP in the ischemic brain. Mol Neurobiol 2014; 51:543-57. [PMID: 24771044 DOI: 10.1007/s12035-014-8710-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 04/09/2014] [Indexed: 12/13/2022]
Abstract
Activating transcription factor 3 (ATF3) is a stress-induced transcription factor with diverse functions under disease states in multiple cell types. ATF3 has neuroprotective action against cerebral ischemia, which may involve caspase 3. However, the molecular mechanisms underlying ATF3 regulation of apoptosis are largely unknown. Here, we used gain- and loss-of-function and rescue approaches to demonstrate ATF3 attenuating hypoxic neuronal apoptosis. As well, the protective effect of ATF3 was mediated by downregulation of carboxyl-terminal modulator protein (CTMP), a pro-apoptotic factor that inhibits the anti-apoptotic Akt/PKB cascade. ATF3 (1) downregulated the mRNA and protein levels of CTMP; (2) its temporal expression pattern was reciprocal to that of CTMP; and (3) nuclear localization suggested that ATF3 may regulate CTMP transcription following hypoxic insult. Reporter assays demonstrated that ATF3 suppressed CTMP transcription, whereas ATF3 fusion with VP16, converting ATF3 to transcriptional activator, boosted CTMP transcription. By contrast, NF-κB increased CTMP transcription, and degradation-resistant IκBα decreased CTMP transcription. ChIP assays further confirmed that binding of ATF3 to the ATF/CREB site hindered NF-κB binding to the CTMP promoter, which repressed CTMP expression. Furthermore, CTMP siRNA treatment reduced hypoxic neuronal apoptosis by increasing p-Akt (Ser473) levels and leaving the upstream ATF3 level unchanged. We have identified an endogenous neuroprotective ATF3→CTMP signal cascade that may be a therapeutic target for reducing ischemic brain injury.
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Affiliation(s)
- Chien-Yu Huang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
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