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Wu CY, Yu JY, Chen YS, Chang HP, Hsieh BY, Lin YH, Ma CY, Tsai SF, Hsieh M. Effects of down-regulated carbonic anhydrase 8 on cell survival and glucose metabolism in human colorectal cancer cell lines. Cell Biochem Funct 2024; 42:e4001. [PMID: 38571370 DOI: 10.1002/cbf.4001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 03/17/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Carbonic anhydrase 8 (CA8) is a member of the α-carbonic anhydrase family but does not catalyze the reversible hydration of carbon dioxide. In the present study, we examined the effects of CA8 on two human colon cancer cell lines, SW480 and SW620, by suppressing CA8 expression through shRNA knockdown. Our results showed that knockdown of CA8 decreased cell growth and cell mobility in SW620 cells, but not in SW480 cells. In addition, downregulated CA8 resulted in a significant decrease of glucose uptake in both SW480 and SW620 cells. Interestingly, stable downregulation of CA8 decreased phosphofructokinase-1 expression but increased glucose transporter 3 (GLUT3) levels in SW620 cells. However, transient downregulation of CA8 fails to up-regulate GLUT3 expression, indicating that the increased GLUT3 observed in SW620-shCA8 cells is a compensatory effect. In addition, the interaction between CA8 and GLUT3 was evidenced by pull-down and IP assays. On the other hand, we showed that metformin, a first-line drug for type II diabetes patients, significantly inhibited cell migration of SW620 cells, depending on the expressions of CA8 and focal adhesion kinase. Taken together, our data demonstrate that when compared to primary colon cancer SW480 cells, metastatic colon cancer SW620 cells respond differently to downregulated CA8, indicating that CA8 in more aggressive cancer cells may play a more important role in controlling cell survival and metformin response. CA8 may affect glucose metabolism- and cell invasion-related molecules in colon cancer, suggesting that CA8 may be a potential target in future cancer therapy.
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Affiliation(s)
- Cheng-Yen Wu
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Jia-Yo Yu
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Yi-Shan Chen
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Hui-Ping Chang
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Benjamin Y Hsieh
- Department of Medicine, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Yu-Hsin Lin
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Chung-Yung Ma
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Shang-Feng Tsai
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
- Department of Internal Medicine, Division of Nephrology, Taichung Veterans General Hospital, Taichung, Taiwan, Republic of China
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | - Mingli Hsieh
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
- Life Science Research Center, Tunghai University, Taichung, Taiwan, Republic of China
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Fan Y, Yan Z, Li T, Li A, Fan X, Qi Z, Zhang J. Primordial Drivers of Diabetes Heart Disease: Comprehensive Insights into Insulin Resistance. Diabetes Metab J 2024; 48:19-36. [PMID: 38173376 PMCID: PMC10850268 DOI: 10.4093/dmj.2023.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/28/2023] [Indexed: 01/05/2024] Open
Abstract
Insulin resistance has been regarded as a hallmark of diabetes heart disease (DHD). Numerous studies have shown that insulin resistance can affect blood circulation and myocardium, which indirectly cause cardiac hypertrophy and ventricular remodeling, participating in the pathogenesis of DHD. Meanwhile, hyperinsulinemia, hyperglycemia, and hyperlipidemia associated with insulin resistance can directly impair the metabolism and function of the heart. Targeting insulin resistance is a potential therapeutic strategy for the prevention of DHD. Currently, the role of insulin resistance in the pathogenic development of DHD is still under active research, as the pathological roles involved are complex and not yet fully understood, and the related therapeutic approaches are not well developed. In this review, we describe insulin resistance and add recent advances in the major pathological and physiological changes and underlying mechanisms by which insulin resistance leads to myocardial remodeling and dysfunction in the diabetic heart, including exosomal dysfunction, ferroptosis, and epigenetic factors. In addition, we discuss potential therapeutic approaches to improve insulin resistance and accelerate the development of cardiovascular protection drugs.
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Affiliation(s)
- Yajie Fan
- Department of Cardiovascular, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Department of Cardiovascular, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Zhipeng Yan
- Department of Cardiovascular, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Tingting Li
- Department of Cardiovascular, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Aolin Li
- Department of Cardiovascular, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xinbiao Fan
- Department of Cardiovascular, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhongwen Qi
- Institute of Gerontology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Junping Zhang
- Department of Cardiovascular, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
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3
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Chen X, Zhang L, Chai W, Tian P, Kim J, Ding J, Zhang H, Liu C, Wang D, Cui X, Pan H. Hypoxic Microenvironment Reconstruction with Synergistic Biofunctional Ions Promotes Diabetic Wound Healing. Adv Healthc Mater 2023; 12:e2301984. [PMID: 37740829 DOI: 10.1002/adhm.202301984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Chronic hypoxia and ischemia make diabetic wounds non-healing. Cellular functions of diabetic chronic wounds are inhibited under a pathological environment. Therefore, this work develops a composite hydrogel system to promote diabetic wound healing. The composite hydrogel system consists of ε-poly-lysine (EPL), calcium peroxide (CP), and borosilicate glass (BG). The hydrogel supplies continuous dissolved oxygen molecules to the wound that can penetrate the skin tissue to restore normal cellular function and promote vascular regeneration. Biofunctional ions released from BGs can recruit more macrophages through neovascularization and modulate macrophage phenotypic transformation. Combining oxygen-mediated vascular regeneration and ion-mediated inflammatory regulation significantly accelerated diabetic wound healing. These findings indicate that this composite hydrogel system holds promise as a novel tissue engineering material.
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Affiliation(s)
- Xiaochen Chen
- School of materials science and engineering, Tongji University, Shanghai, 201804, P. R. China
| | - Liyan Zhang
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Wenwen Chai
- School of materials science and engineering, Tongji University, Shanghai, 201804, P. R. China
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Pengfei Tian
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Jua Kim
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Jingxin Ding
- School of materials science and engineering, Tongji University, Shanghai, 201804, P. R. China
| | - Hao Zhang
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Chunyu Liu
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Deping Wang
- School of materials science and engineering, Tongji University, Shanghai, 201804, P. R. China
| | - Xu Cui
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Haobo Pan
- Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
- Shenzhen Healthemes Biotechnology Co., Ltd, Shenzhen, 518071, P. R. China
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4
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Atlante A, Valenti D. Mitochondrial Complex I and β-Amyloid Peptide Interplay in Alzheimer's Disease: A Critical Review of New and Old Little Regarded Findings. Int J Mol Sci 2023; 24:15951. [PMID: 37958934 PMCID: PMC10650435 DOI: 10.3390/ijms242115951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder and the main cause of dementia which is characterized by a progressive cognitive decline that severely interferes with daily activities of personal life. At a pathological level, it is characterized by the accumulation of abnormal protein structures in the brain-β-amyloid (Aβ) plaques and Tau tangles-which interfere with communication between neurons and lead to their dysfunction and death. In recent years, research on AD has highlighted the critical involvement of mitochondria-the primary energy suppliers for our cells-in the onset and progression of the disease, since mitochondrial bioenergetic deficits precede the beginning of the disease and mitochondria are very sensitive to Aβ toxicity. On the other hand, if it is true that the accumulation of Aβ in the mitochondria leads to mitochondrial malfunctions, it is otherwise proven that mitochondrial dysfunction, through the generation of reactive oxygen species, causes an increase in Aβ production, by initiating a vicious cycle: there is therefore a bidirectional relationship between Aβ aggregation and mitochondrial dysfunction. Here, we focus on the latest news-but also on neglected evidence from the past-concerning the interplay between dysfunctional mitochondrial complex I, oxidative stress, and Aβ, in order to understand how their interplay is implicated in the pathogenesis of the disease.
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Affiliation(s)
- Anna Atlante
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via G. Amendola 122/O, 70126 Bari, Italy;
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Vásquez-Londoño CA, Howes MJR, Costa GM, Arboleda G, Rojas-Cardozo MA. Scutellaria incarnata Vent. root extract and isolated phenylethanoid glycosides are neuroprotective against C 2-ceramide toxicity. JOURNAL OF ETHNOPHARMACOLOGY 2023; 307:116218. [PMID: 36738946 DOI: 10.1016/j.jep.2023.116218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 01/13/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Neuronal death is a central process in neurodegenerative diseases and represents a therapeutic challenge for their prevention and treatment. Scutellaria incarnata Vent. roots are used traditionally in Colombia for central nervous system conditions including those affecting cognitive functions, but their chemistry and neuroprotective action remain to be explored to understand the scientific basis for their medicinal uses. In this study, S. incarnata roots are investigated to assess whether they have neuroprotective effects that could provide some explanation for their traditional use in neurodegenerative diseases. AIM OF THE STUDY To evaluate the neuroprotective effect of S. incarnata roots and its chemical constituents against C2-ceramide-induced cell death in Cath.-a-differentiated (CAD) cells. MATERIALS AND METHODS S. incarnata root ethanol extract was fractionated and compounds were isolated by column chromatography; their structures were elucidated by nuclear magnetic resonance spectroscopy, mass spectrometry and infrared spectroscopy. The cytotoxic and neuroprotective effects against C2-ceramide of S. incarnata root extract, fractions and isolated compounds were assessed in CAD cells. RESULTS S. incarnata root extract and its n-butanol fraction were not cytotoxic but showed neuroprotective effects against C2-ceramide toxicity in CAD cells. The phenylethanoid glycosides incarnatoside (isolated for the first time) and stachysoside C (12.5, 25 and 50 μg/mL) from S. incarnata roots also protected CAD cells against C2-ceramide without inducing cytotoxic effects. CONCLUSION The observed neuroprotective effects of S. incarnata root extract and isolated phenylethanoid glycosides in CAD cells provide an ethnopharmacological basis for the traditional use of this species in Colombia for central nervous system disorders.
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Affiliation(s)
- Carlos A Vásquez-Londoño
- Universidad Nacional de Colombia-Sede Bogotá, Faculty of Sciences, Department of Pharmacy, GIFFUN, Bogotá, 111321, Colombia.
| | | | - Geison M Costa
- Pontificia Universidad Javeriana, Faculty of Sciences, Department of Pharmacy, Bogotá, 110231, Colombia
| | - Gonzalo Arboleda
- Universidad Nacional de Colombia-Sede Bogotá, Faculty of Medicine, Department of Pathology - Genetic Institute, Bogotá, 111231, Colombia
| | - Maritza A Rojas-Cardozo
- Universidad Nacional de Colombia-Sede Bogotá, Faculty of Sciences, Department of Pharmacy, GIFFUN, Bogotá, 111321, Colombia.
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Crivelli SM, Luo Q, Kruining DV, Giovagnoni C, Mané-Damas M, den Hoedt S, Berkes D, De Vries HE, Mulder MT, Walter J, Waelkens E, Derua R, Swinnen JV, Dehairs J, Wijnands EPM, Bieberich E, Losen M, Martinez-Martinez P. FTY720 decreases ceramides levels in the brain and prevents memory impairments in a mouse model of familial Alzheimer's disease expressing APOE4. Biomed Pharmacother 2022; 152:113240. [PMID: 35689862 DOI: 10.1016/j.biopha.2022.113240] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/31/2022] [Accepted: 06/02/2022] [Indexed: 11/24/2022] Open
Abstract
The protection mediated by the bioactive sphingolipid sphingosine-1-phosphate (S1P) declines during Alzheimer's disease (AD) progression, especially in patients carrying the apolipoprotein E ε4 (APOE4) isoform. The drug FTY720 mimics S1P bioactivity, but its efficacy in treating AD is unclear. Two doses of FTY720 (0.1 mg / kg and 0.5 mg / kg daily) were given by oral gavage for 15 weeks to transgenic mouse models of familial AD carrying human apolipoprotein E (APOE) APOE3 (E3FAD) or APOE4 (E4FAD). After 12 weeks of treatment, animals were subjected to behavioral tests for memory, locomotion, and anxiety. Blood was withdrawn at different time points and brains were collected for sphingolipids analysis by mass spectrometry, gene expression by RT-PCR and Aβ quantification by ELISA. We discovered that low levels of S1P in the plasma is associated with a higher probability of failing the memory test and that FTY720 prevents memory impairments in E4FAD. The beneficial effect of FTY720 was induced by a shift of the sphingolipid metabolism in the brain towards a lower production of toxic metabolites, like ceramide d18:1/16:0 and d18:1/22:0, and reduction of amyloid-β burden and inflammation. In conclusion, we provide further evidence of the druggability of the sphingolipid system in AD.
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Affiliation(s)
- Simone M Crivelli
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands; Department of Physiology, University of Kentucky College of Medicine, Lexington 40506, KY, USA.
| | - Qian Luo
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands
| | - Daan van Kruining
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands
| | - Caterina Giovagnoni
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands
| | - Marina Mané-Damas
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands
| | - Sandra den Hoedt
- Department of Internal Medicine, Laboratory Vascular Medicine, Erasmus MC University Medical Center, Rotterdam 3000CA, the Netherlands
| | - Dusan Berkes
- Department of Organic Chemistry, Slovak University of Technology, Radlinského 9, 81237 Bratislava, Slovak Republic
| | - Helga E De Vries
- Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, Amsterdam UMC, Amsterdam 1007MB, the Netherlands
| | - Monique T Mulder
- Department of Internal Medicine, Laboratory Vascular Medicine, Erasmus MC University Medical Center, Rotterdam 3000CA, the Netherlands
| | - Jochen Walter
- Department of Neurology, University Hospital Bonn, University of Bonn, Bonn D-53127, Germany
| | - Etienne Waelkens
- Laboratory of Protein Phosphorylation and Proteomics, KU Leuven, Leuven 3000, Belgium
| | - Rita Derua
- Laboratory of Protein Phosphorylation and Proteomics, KU Leuven, Leuven 3000, Belgium
| | - Johannes V Swinnen
- Laboratory of Lipid Metabolism and Cancer, KU Leuven, Leuven 3000, Belgium
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism and Cancer, KU Leuven, Leuven 3000, Belgium
| | - Erwin P M Wijnands
- Department of Pathology, Maastricht University, Maastricht 6200MD, the Netherlands
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky College of Medicine, Lexington 40506, KY, USA; Veterans Affairs Medical Center, Lexington, KY 40502, USA
| | - Mario Losen
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands
| | - Pilar Martinez-Martinez
- Maastricht University, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht 6200MD, the Netherlands.
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Yuan Y, Chen J, Ge X, Deng J, Xu X, Zhao Y, Wang H. Activation of ERK-Drp1 signaling promotes hypoxia-induced Aβ accumulation by upregulating mitochondrial fission and BACE1 activity. FEBS Open Bio 2021; 11:2740-2755. [PMID: 34403210 PMCID: PMC8487051 DOI: 10.1002/2211-5463.13273] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/29/2021] [Accepted: 08/16/2021] [Indexed: 12/20/2022] Open
Abstract
Hypoxia is a risk factor for Alzheimer's disease (AD). Besides, mitochondrial fission is increased in response to hypoxia. In this study, we sought to investigate whether hypoxia‐induced mitochondrial fission plays a critical role in regulating amyloid‐β (Aβ) production. Hypoxia significantly activated extracellular signal‐regulated kinase (ERK), increased phosphorylation of dynamin‐related protein 1 (Drp1) at serine 616, and decreased phosphorylation of Drp1 at serine 637. Importantly, hypoxia triggered mitochondrial dysfunction, elevated β‐secretase 1 (BACE1) and γ‐secretase activities, and promoted Aβ accumulation in HEK293 cells transfected with β‐amyloid precursor protein (APP) plasmid harboring the Swedish and Indiana familial Alzheimer's disease mutations (APPSwe/Ind HEK293 cells). Then, we investigated whether the ERK inhibitor PD325901 and Drp1 inhibitor mitochondrial division inhibitor‐1 (Mdivi‐1) would attenuate hypoxia‐induced mitochondrial fission and Aβ generation in APPSwe/Ind HEK293 cells. PD325901 and Mdivi‐1 inhibited phosphorylation of Drp1 at serine 616, resulting in reduced mitochondrial fission under hypoxia. Furthermore, hypoxia‐induced mitochondrial dysfunction, BACE1 activation, and Aβ accumulation were downregulated by PD325901 and Mdivi‐1. Our data demonstrate that hypoxia induces mitochondrial fission, impairs mitochondrial function, and facilitates Aβ generation. The ERK–Drp1 signaling pathway is partly involved in the hypoxia‐induced Aβ generation by regulating mitochondrial fission and BACE1 activity. Therefore, inhibition of hypoxia‐induced mitochondrial fission may prevent or slow the progression of AD.
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Affiliation(s)
- Yuan Yuan
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China
| | - Jingjiong Chen
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China
| | - Xuhua Ge
- Department of General Medicine, Yangpu Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jiangshan Deng
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China
| | - Xiaofeng Xu
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China
| | - Yuwu Zhao
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China
| | - Hongmei Wang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China
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Ceramide analog [ 18F]F-HPA-12 detects sphingolipid disbalance in the brain of Alzheimer's disease transgenic mice by functioning as a metabolic probe. Sci Rep 2020; 10:19354. [PMID: 33168861 PMCID: PMC7652882 DOI: 10.1038/s41598-020-76335-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/22/2020] [Indexed: 02/06/2023] Open
Abstract
The metabolism of ceramides is deregulated in the brain of Alzheimer’s disease (AD) patients and is associated with apolipoprotein (APO) APOE4 and amyloid-β pathology. However, how the ceramide metabolism changes over time in AD, in vivo, remains unknown. Distribution and metabolism of [18F]F-HPA-12, a radio-fluorinated version of the ceramide analog N-(3-hydroxy-1-hydroxymethyl-3-phenylpropyl) dodecanamide, was investigated in the brain of AD transgenic mouse models (FAD) on an APOE4 or APOE3 genetic background, by positron emission tomography and by gamma counter. We found that FAD mice displayed a higher uptake of [18F]F-HPA-12 in the brain, independently from the APOE4 or APOE3 genetic background. FAD mice could be distinguished from littermate control animals with a sensitivity of 85.7% and a specificity of 87.5%, by gamma counter measurements. Metabolic analysis of [18F]F-HPA-12 in the brain suggested that the tracer is degraded less efficiently in the FAD mice. Furthermore, the radioactive signal registered in the hippocampus correlated with an increase of Cer d18:1/20:2 levels measured in the same brain region by mass spectrometry. Our data gives additional proof that ceramide metabolism is different in FAD mice compared to controls. Ceramide analogs like HPA-12 may function as metabolic probes to study ceramide disbalance in the brain.
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Wang H, Zhang T, Ge X, Chen J, Zhao Y, Fu J. Parkin overexpression attenuates Aβ-induced mitochondrial dysfunction in HEK293 cells by restoring impaired mitophagy. Life Sci 2020; 244:117322. [PMID: 31958419 DOI: 10.1016/j.lfs.2020.117322] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/13/2020] [Accepted: 01/13/2020] [Indexed: 10/25/2022]
Abstract
AIMS Mitochondrial dysfunction is an early prominent feature of Alzheimer's disease (AD). In the present study, we sought to investigate whether defective mitophagy is tightly related to amyloid-β (Aβ)-induced mitochondrial dysfunction. MAIN METHODS Immunofluorescence, western blot and transmission electron microscopy were used to examine mitophagy. Mitochondrial membrane potential was assessed using the JC-1 dye. Mitochondrial ROS was detected using MitoSOX™ Red staining. KEY FINDINGS Aβ induced mitochondrial dysfunction in HEK293 cells. Moreover, Aβ induced an increase in parkin translocation to mitochondria and led to a drastic reduction in cytosolic parkin. Furthermore, Aβ-treated cells displayed a microtubule-associated protein 1 light chain 3 (LC3) punctate pattern and elevated mitochondrial LC3-II levels, suggesting the upregulation of mitophagy. Notably, Aβ induced the accumulation of mitochondrial p62, which was associated with impaired mitophagy. In addition, Aβ-treated cells exhibited fragmented or swollen mitochondria with severely decreased cristae. We then investigated whether overexpression of parkin could protect cells against Aβ-induced mitochondrial dysfunction. Interestingly, parkin overexpression inhibited Aβ-induced mitochondrial dysfunction. Besides, parkin overexpression increased cytosolic and mitochondrial parkin levels as well as mitochondrial LC3-II levels in Aβ-treated cells. Additionally, parkin overexpression reversed the accumulation of p62 in mitochondria, indicating that parkin overexpression restored impaired mitophagy in Aβ-treated cells. Importantly, parkin overexpression remarkably reversed Aβ-induced mitochondrial fragmentation. SIGNIFICANCE Our data demonstrate that overexpression of parkin ameliorates impaired mitophagy and promotes the removal of damaged mitochondria in Aβ-treated cells, indicating that upregulation of parkin-mediated mitophagy may be a potential strategy for the therapy of AD.
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Affiliation(s)
- Hongmei Wang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Ting Zhang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Xuhua Ge
- Department of General Medicine, Yangpu Hospital Affiliated to Tongji University, Shanghai, China
| | - Jingjiong Chen
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yuwu Zhao
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
| | - Jianliang Fu
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
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10
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Alzheimer's Disease and Diabetes: Insulin Signaling as the Bridge Linking Two Pathologies. Mol Neurobiol 2020; 57:1966-1977. [PMID: 31900863 DOI: 10.1007/s12035-019-01858-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/12/2019] [Indexed: 12/22/2022]
Abstract
Alzheimer's (or Alzheimer) disease (AD) is the most prevalent subset of dementia, affecting elderly populations worldwide. The cumulative costs of the AD care are rapidly accelerating as the average lifespan increases. Onset and risk factors for AD and AD-like dementias have been largely unknown until recently. Studies show that chronic type II diabetes mellitus (DM) is closely associated with neurodegeneration, especially AD. Type II DM is characterized by the cells' inability to take up insulin, as well as chronic hyperglycemia. In the central nervous system, insulin has crucial regulatory roles, while chronic hyperglycemia leads to formation and accumulation of advanced glycation end products (AGEs). AGEs are the major contributor to insulin resistance in diabetic cells, due to their regulatory role on sirtuin expression. Insulin activity in the central nervous system is known to interact with key proteins affected in neurodegenerative conditions, such as amyloid-β precursor protein (AβPP or APP), huntingtin-associated protein-1 (HAP1), Abelson helper integration site-1 (AHI1 or Jouberin), kinesin, and tau. Sirtuins have been theorized to be the mechanism for insulin resistance, and have been found to be affected in neurodegenerative conditions as well. There are hints that all these neuronal proteins may be closely related, although the mechanisms remain unclear. This review will gather existing research on these proteins and highlight the link between neurodegenerative conditions and diabetes mellitus.
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11
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Jęśko H, Stępień A, Lukiw WJ, Strosznajder RP. The Cross-Talk Between Sphingolipids and Insulin-Like Growth Factor Signaling: Significance for Aging and Neurodegeneration. Mol Neurobiol 2019; 56:3501-3521. [PMID: 30140974 PMCID: PMC6476865 DOI: 10.1007/s12035-018-1286-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/25/2018] [Indexed: 12/20/2022]
Abstract
Bioactive sphingolipids: sphingosine, sphingosine-1-phosphate (S1P), ceramide, and ceramide-1-phosphate (C1P) are increasingly implicated in cell survival, proliferation, differentiation, and in multiple aspects of stress response in the nervous system. The opposite roles of closely related sphingolipid species in cell survival/death signaling is reflected in the concept of tightly controlled sphingolipid rheostat. Aging has a complex influence on sphingolipid metabolism, disturbing signaling pathways and the properties of lipid membranes. A metabolic signature of stress resistance-associated sphingolipids correlates with longevity in humans. Moreover, accumulating evidence suggests extensive links between sphingolipid signaling and the insulin-like growth factor I (IGF-I)-Akt-mTOR pathway (IIS), which is involved in the modulation of aging process and longevity. IIS integrates a wide array of metabolic signals, cross-talks with p53, nuclear factor κB (NF-κB), or reactive oxygen species (ROS) and influences gene expression to shape the cellular metabolic profile and stress resistance. The multiple connections between sphingolipids and IIS signaling suggest possible engagement of these compounds in the aging process itself, which creates a vulnerable background for the majority of neurodegenerative disorders.
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Affiliation(s)
- Henryk Jęśko
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Pawińskiego, 5, 02-106, Poland
| | - Adam Stępień
- Central Clinical Hospital of the Ministry of National Defense, Department of Neurology, Military Institute of Medicine, Warsaw, Szaserów, 128, 04-141, Poland
| | - Walter J Lukiw
- LSU Neuroscience Center and Departments of Neurology and Ophthalmology, Louisiana State University School of Medicine, New Orleans, USA
| | - Robert P Strosznajder
- Laboratory of Preclinical Research and Environmental Agents, Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Pawińskiego, 5, 02-106, Poland.
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12
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Lee HK, Kwon B, Lemere CA, de la Monte S, Itamura K, Ha AY, Querfurth HW. mTORC2 (Rictor) in Alzheimer's Disease and Reversal of Amyloid-β Expression-Induced Insulin Resistance and Toxicity in Rat Primary Cortical Neurons. J Alzheimers Dis 2018; 56:1015-1036. [PMID: 28035937 DOI: 10.3233/jad-161029] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mammalian target of rapamycin complex 1 (mTORC1), a nutrient sensor and central controller of cell growth and proliferation, is altered in various models of Alzheimer's disease (AD). Even less studied or understood in AD is mammalian target of rapamycin complex 2 (mTORC2) that influences cellular metabolism, in part through the regulations of Akt/PKB and SGK. Dysregulation of insulin/PI3K/Akt signaling is another important feature of AD pathogenesis. We found that both total mTORC1 and C2 protein levels and individual C1 and C2 enzymatic activities were decreased in human AD brain samples. In two rodent AD models, mTORC1 and C2 activities were also decreased. In a neuronal culture model of AD characterized by accumulation of cellular amyloid-β (Aβ)42, mTORC1 activity was reduced. Autophagic vesicles and markers were correspondingly increased and new protein synthesis was inhibited, consistent with mTORC1 hypofunction. Interestingly, mTORC2 activity in neural culture seemed resistant to the effects of intracellular amyloid. In various cell lines, Aβ expression provoked insulin resistance, characterized by inhibition of stimulated Akt phosphorylation, and an increase in negative mTORC1 regular, p-AMPK, itself a nutrient sensor. Rapamycin decreased phospho-mTOR and to lesser degree p-Rictor. This further suppression of mTORC1 activity protected cells from Aβ-induced toxicity and insulin resistance. More striking, Rictor over-expression fully reversed the Aβ-effects on primary neuronal cultures. Finally, using in vitro assay, Rictor protein addition completely overcame oligomeric Aβ-induced inhibition of the PDK-Akt activation step. We conclude that striking a new balance by restoring mTORC2 abundance and/or inhibition of mTORC1 has therapeutic potential in AD.
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Affiliation(s)
- Han-Kyu Lee
- Department of Neurology, Rhode Island Hospital and Brown University Warren Alpert Medical School, Providence, RI, USA
| | - Bumsup Kwon
- Department of Neurology, Rhode Island Hospital and Brown University Warren Alpert Medical School, Providence, RI, USA
| | - Cynthia A Lemere
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Suzanne de la Monte
- Department of Pathology, Rhode Island Hospital and Brown University Warren Alpert Medical School, Providence, RI, USA
| | - Kyohei Itamura
- Department of Neurology, Rhode Island Hospital and Brown University Warren Alpert Medical School, Providence, RI, USA
| | - Austin Y Ha
- Department of Neurology, Rhode Island Hospital and Brown University Warren Alpert Medical School, Providence, RI, USA
| | - Henry W Querfurth
- Department of Neurology, Rhode Island Hospital and Brown University Warren Alpert Medical School, Providence, RI, USA
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13
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Moreno-Navarrete JM, Jové M, Padró T, Boada J, Ortega F, Ricart W, Pamplona R, Badimón L, Portero-Otín M, Fernández-Real JM. Adipocyte lipopolysaccharide binding protein (LBP) is linked to a specific lipidomic signature. Obesity (Silver Spring) 2017; 25:391-400. [PMID: 28001010 DOI: 10.1002/oby.21711] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/19/2016] [Accepted: 10/06/2016] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Lipopolysaccharide binding protein (LBP) is part of a family of structurally and functionally related lipid transfer proteins. This study aimed to investigate the associations of LBP with the lipid composition of human adipose tissue. METHODS Lipidomic analysis was performed in whole adipose tissue. To validate the associations found, LBP was knocked down (KD) in 3T3-L1 adipocytes, and lipidomic profile was evaluated by nontargeted lipidomics. RESULTS LBP gene expression was negatively associated with phosphatidylcholine, phosphatidylserine, and sphingomyelin relative abundance in vivo. LBP expression was also decreased in those samples with the highest docosahexanoic content, implicated in the resolution of inflammation. The KD of LBP (by ∼70%) led to sharp changes in the lipidome of adipocytes. Of note, specific plasmalogen species PE(O-16:0/22:5), PE(38:2), odd chain glycerolipids, and cholesteryl linoleate were upregulated by LBP KD. In contrast, GM3 gangliosides, several ceramides, a triacylglycerol potentially containing arachidonate, and cholesteryl palmitate were downregulated by LBP KD. CONCLUSIONS LBP seems to play a role in the regulation of lipid composition of adipose tissue linked to resilience to inflammation.
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Affiliation(s)
- José María Moreno-Navarrete
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomèdica de Girona (IdIBGi), CIBEROBN (CB06/03/010) and Instituto de Salud Carlos III (ISCIII), Girona, Spain
| | - Mariona Jové
- NUTREN-Nutrigenomics, PCiTAL-IRBLLEIDA-Universitat de Lleida, Lleida, Spain
| | - Teresa Padró
- Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Barcelona, Spain
| | - Jordi Boada
- NUTREN-Nutrigenomics, PCiTAL-IRBLLEIDA-Universitat de Lleida, Lleida, Spain
| | - Francisco Ortega
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomèdica de Girona (IdIBGi), CIBEROBN (CB06/03/010) and Instituto de Salud Carlos III (ISCIII), Girona, Spain
| | - Wifredo Ricart
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomèdica de Girona (IdIBGi), CIBEROBN (CB06/03/010) and Instituto de Salud Carlos III (ISCIII), Girona, Spain
| | - Reinald Pamplona
- NUTREN-Nutrigenomics, PCiTAL-IRBLLEIDA-Universitat de Lleida, Lleida, Spain
| | - Lina Badimón
- Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Barcelona, Spain
| | | | - José Manuel Fernández-Real
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomèdica de Girona (IdIBGi), CIBEROBN (CB06/03/010) and Instituto de Salud Carlos III (ISCIII), Girona, Spain
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14
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Schaefer PM, von Einem B, Walther P, Calzia E, von Arnim CAF. Metabolic Characterization of Intact Cells Reveals Intracellular Amyloid Beta but Not Its Precursor Protein to Reduce Mitochondrial Respiration. PLoS One 2016; 11:e0168157. [PMID: 28005987 PMCID: PMC5178995 DOI: 10.1371/journal.pone.0168157] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/24/2016] [Indexed: 12/17/2022] Open
Abstract
One hallmark of Alzheimer´s disease are senile plaques consisting of amyloid beta (Aβ), which derives from the processing of the amyloid precursor protein (APP). Mitochondrial dysfunction has been linked to the pathogenesis of Alzheimer´s disease and both Aβ and APP have been reported to affect mitochondrial function in isolated systems. However, in intact cells, considering a physiological localization of APP and Aβ, it is pending what triggers the mitochondrial defect. Thus, the aim of this study was to dissect the impact of APP versus Aβ in inducing mitochondrial alterations with respect to their subcellular localization. We performed an overexpression of APP or beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), increasing APP and Aβ levels or Aβ alone, respectively. Conducting a comprehensive metabolic characterization we demonstrate that only APP overexpression reduced mitochondrial respiration, despite lower extracellular Aβ levels compared to BACE overexpression. Surprisingly, this could be rescued by a gamma secretase inhibitor, oppositionally indicating an Aβ-mediated mitochondrial toxicity. Analyzing Aβ localization revealed that intracellular levels of Aβ and an increased spatial association of APP/Aβ with mitochondria are associated with reduced mitochondrial respiration. Thus, our data provide marked evidence for a prominent role of intracellular Aβ accumulation in Alzheimer´s disease associated mitochondrial dysfunction. Thereby it highlights the importance of the localization of APP processing and intracellular transport as a decisive factor for mitochondrial function, linking two prominent hallmarks of neurodegenerative diseases.
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Affiliation(s)
| | | | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Ulm, Germany
| | - Enrico Calzia
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Ulm, Germany
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15
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Palomera-Avalos V, Griñán-Ferré C, Puigoriol-Ilamola D, Camins A, Sanfeliu C, Canudas AM, Pallàs M. Resveratrol Protects SAMP8 Brain Under Metabolic Stress: Focus on Mitochondrial Function and Wnt Pathway. Mol Neurobiol 2016; 54:1661-1676. [PMID: 26873850 DOI: 10.1007/s12035-016-9770-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/01/2016] [Indexed: 01/06/2023]
Abstract
Metabolic stress induced by high-fat (HF) diet leads to cognitive dysfunction and aging, but the physiological mechanisms are not fully understood. Senescence-accelerated prone mouse (SAMP8) models were conducted under metabolic stress conditions by feeding HF for 15 weeks, and the preventive effect of resveratrol was studied. This dietary strategy demonstrates cognitive impairment in SAMP8-HF and significant preventive effect by resveratrol-treated animals. Hippocampal changes in the proteins involved in mitochondrial dynamics optic atrophy-1 protein (OPA1) and mitofusin 2 (MFN2) comprised a differential feature found in SAMP8-HF that was prevented by resveratrol. Electronic microscopy showed a larger mitochondria in SAMP8-HF + resveratrol (SAMP8-HF + RV) than in SAMP8-HF, indicating increases in fusion processes in resveratrol-treated mice. According to the mitochondrial morphology, significant increases in the I-NDUFB8, II-SDNB, III-UQCRC2, and V-ATPase complexes, in addition to that of voltage-dependent anion channel 1 (VDAC1)/porin, were found in resveratrol-treated animals with regard to SAMP8-HF, reaching control-animal levels. Moreover, tumor necrosis factor alpha (TNF-α) and interleukin (IL-6) were increased after HF, and resveratrol prevents its increase. Moreover, we found that the HF diet affected the Wnt pathway, as demonstrated by β-catenin inactivation and modification in the expression of several components of this pathway. Resveratrol induced strong activation of β-catenin. The metabolic stress rendered in the cognitive and cellular pathways altered in SAMP8 focus on different targets in order to act on preventing cognitive impairment in neurodegeneration, and resveratrol can offer therapeutic possibilities for preventive strategies in aging or neurodegenerative conditions.
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Affiliation(s)
- V Palomera-Avalos
- Department of Pharmacology, Toxicology and Therapeutic Chemistry (Pharmacology Section) and Institute of Neuroscience, University of Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain
| | - C Griñán-Ferré
- Department of Pharmacology, Toxicology and Therapeutic Chemistry (Pharmacology Section) and Institute of Neuroscience, University of Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain
| | - D Puigoriol-Ilamola
- Department of Pharmacology, Toxicology and Therapeutic Chemistry (Pharmacology Section) and Institute of Neuroscience, University of Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain
| | - A Camins
- Department of Pharmacology, Toxicology and Therapeutic Chemistry (Pharmacology Section) and Institute of Neuroscience, University of Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain
| | - C Sanfeliu
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB), CSIC, and IDIBAPS, 08036, Barcelona, Spain
| | - A M Canudas
- Department of Pharmacology, Toxicology and Therapeutic Chemistry (Pharmacology Section) and Institute of Neuroscience, University of Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain
| | - M Pallàs
- Department of Pharmacology, Toxicology and Therapeutic Chemistry (Pharmacology Section) and Institute of Neuroscience, University of Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain. .,Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Universitat de Barcelona, Avda. Joan XXIII s/n, 08028, Barcelona, Spain.
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16
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Palmitate activates mTOR/p70S6K through AMPK inhibition and hypophosphorylation of raptor in skeletal muscle cells: Reversal by oleate is similar to metformin. Biochimie 2015; 118:141-50. [PMID: 26344902 DOI: 10.1016/j.biochi.2015.09.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/02/2015] [Indexed: 01/24/2023]
Abstract
Excessive saturated free fatty acids (SFFAs; e.g. palmitate) in blood are a pathogenic factor in diabetes, obesity, cardiovascular disease and liver failure. In contrast, monounsaturated free fatty acids (e.g. oleate) prevent the toxic effect of SFFAs in various types of cells. The mechanism is poorly understood and involvement of the mTOR complex is untested. In the present study, we demonstrate that oleate preconditioning, as well as coincubation, completely prevented palmitate-induced markers of inflammatory signaling, insulin resistance and cytotoxicity in C2C12 myotubes. We then examined the effect of palmitate and/or oleate on the mammalian target of rapamycin (mTOR) signal path and whether their link is mediated by AMP-activated protein kinase (AMPK). Palmitate decreased the phosphorylation of raptor and 4E-BP1 while increasing the phosphorylation of p70S6K. Palmitate also inhibited phosphorylation of AMPK, but did not change the phosphorylated levels of mTOR or rictor. Oleate completely prevented the palmitate-induced dysregulation of mTOR components and restored pAMPK whereas alone it produced no signaling changes. To understand this more, we show activation of AMPK by metformin also prevented palmitate-induced changes in the phosphorylations of raptor and p70S6K, confirming that the mTORC1/p70S6K signaling pathway is responsive to AMPK activity. By contrast, inhibition of AMPK phosphorylation by Compound C worsened palmitate-induced changes and correspondingly blocked the protective effect of oleate. Finally, metformin modestly attenuated palmitate-induced insulin resistance and cytotoxicity, as did oleate. Our findings indicate that palmitate activates mTORC1/p70S6K signaling by AMPK inhibition and phosphorylation of raptor. Oleate reverses these effects through a metformin-like facilitation of AMPK.
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