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Ríos JA, Bórquez JC, Godoy JA, Zolezzi JM, Furrianca MC, Inestrosa NC. Emerging role of Metformin in Alzheimer's disease: A translational view. Ageing Res Rev 2024:102439. [PMID: 39074563 DOI: 10.1016/j.arr.2024.102439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 07/23/2024] [Accepted: 07/23/2024] [Indexed: 07/31/2024]
Abstract
Alzheimer's disease (AD) constitutes a major public-health issue of our time. Regrettably, despite our considerable understanding of the pathophysiological aspects of this disease, current interventions lead to poor outcomes. Furthermore, experimentally promising compounds have continuously failed when translated to clinical trials. Along with increased population ageing, Type 2 Diabetes Mellitus (T2DM) has become an extremely common condition, mainly due to unbalanced dietary habits. Substantial epidemiological evidence correlates T2DM with cognitive impairment as well. Considering that brain insulin resistance, mitochondrial dysfunction, oxidative stress, and amyloidogenesis are common phenomena, further approaching the common features among these pathological conditions. Metformin constitutes the first-choice drug to preclude insulin resistance in T2DM clinical management. Experimental evidence suggests that its functions might include neuroprotective effects, in addition to its hypoglycemic activity. This review aims to summarize and discuss current knowledge of experimental data on metformin on this path towards translational medicine. Finally, we discuss the controversial data of responses to metformin in vitro, and in vivo, animal models and human studies.
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Affiliation(s)
- Juvenal A Ríos
- Facultad de Medicina y Ciencia, Escuela de Medicina, Universidad San Sebastián, Santiago, Chile
| | - Juan Carlos Bórquez
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Escuela de Medicina, Universidad de Magallanes, Punta Arenas, Chile; Facultad de Ciencias de la Salud, Universidad de Magallanes, Punta Arenas, Chile
| | - Juan A Godoy
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan M Zolezzi
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Escuela de Medicina, Universidad de Magallanes, Punta Arenas, Chile
| | | | - Nibaldo C Inestrosa
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Escuela de Medicina, Universidad de Magallanes, Punta Arenas, Chile.
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2
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Nagdev PK, Agnivesh PK, Roy A, Sau S, Kalia NP. Exploring and exploiting the host cell autophagy during Mycobacterium tuberculosis infection. Eur J Clin Microbiol Infect Dis 2023; 42:1297-1315. [PMID: 37740791 DOI: 10.1007/s10096-023-04663-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 09/06/2023] [Indexed: 09/25/2023]
Abstract
Tuberculosis, caused by Mycobacterium tuberculosis, is a fatal infectious disease that prevails to be the second leading cause of death from a single infectious agent despite the availability of multiple drugs for treatment. The current treatment regimen involves the combination of several drugs for 6 months that remain ineffective in completely eradicating the infection because of several drawbacks, such as the long duration of treatment and the side effects of drugs causing non-adherence of patients to the treatment regimen. Autophagy is an intracellular degradative process that eliminates pathogens at the early stages of infection. Mycobacterium tuberculosis's unique autophagy-blocking capability makes it challenging to eliminate compared to usual pathogens. The present review discusses recent advances in autophagy-inhibiting factors and mechanisms that could be exploited to identify autophagy-inducing chemotherapeutics that could be used as adjunctive therapy with the existing first-line anti-TB agent to shorten the duration of therapy and enhance cure rates from multidrug-resistant tuberculosis (MDR-TB) and extreme drug-resistant tuberculosis (XDR-TB).
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Affiliation(s)
- Pavan Kumar Nagdev
- Department of Biological Sciences (Pharmacology and Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Puja Kumari Agnivesh
- Department of Biological Sciences (Pharmacology and Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Arnab Roy
- Department of Biological Sciences (Pharmacology and Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Shashikanta Sau
- Department of Biological Sciences (Pharmacology and Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Nitin Pal Kalia
- Department of Biological Sciences (Pharmacology and Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India.
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3
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Chen W, Zhang Y, Zhai X, Xie L, Guo Y, Chen C, Li Y, Wang F, Zhu Z, Zheng L, Wan J, Li P. Microglial phagocytosis and regulatory mechanisms after stroke. J Cereb Blood Flow Metab 2022; 42:1579-1596. [PMID: 35491825 PMCID: PMC9441720 DOI: 10.1177/0271678x221098841] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Stroke, including ischemic stroke and hemorrhagic stroke can cause massive neuronal death and disruption of brain structure, which is followed by secondary inflammatory injury initiated by pro-inflammatory molecules and cellular debris. Phagocytic clearance of cellular debris by microglia, the brain's scavenger cells, is pivotal for neuroinflammation resolution and neurorestoration. However, microglia can also exacerbate neuronal loss by phagocytosing stressed-but-viable neurons in the penumbra, thereby expanding the injury area and hindering neurofunctional recovery. Microglia constantly patrol the central nervous system using their processes to scour the cellular environment and start or cease the phagocytosis progress depending on the "eat me" or "don't eat me'' signals on cellular surface. An optimal immune response requires a delicate balance between different phenotypic states to regulate neuro-inflammation and facilitate reconstruction after stroke. Here, we examine the literature and discuss the molecular mechanisms and cellular pathways regulating microglial phagocytosis, their resulting effects in brain injury and neural regeneration, as well as the potential therapeutic targets that might modulate microglial phagocytic activity to improve neurological function after stroke.
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Affiliation(s)
- Weijie Chen
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yueman Zhang
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaozhu Zhai
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lv Xie
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunlu Guo
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Chen
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Li
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fajun Wang
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Ziyu Zhu
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Zheng
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jieqing Wan
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peiying Li
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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4
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Triggle CR, Mohammed I, Bshesh K, Marei I, Ye K, Ding H, MacDonald R, Hollenberg MD, Hill MA. Metformin: Is it a drug for all reasons and diseases? Metabolism 2022; 133:155223. [PMID: 35640743 DOI: 10.1016/j.metabol.2022.155223] [Citation(s) in RCA: 93] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/22/2022] [Accepted: 05/25/2022] [Indexed: 12/15/2022]
Abstract
Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.
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Affiliation(s)
- Chris R Triggle
- Department of Pharmacology, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar; Department of Medical Education, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar.
| | - Ibrahim Mohammed
- Department of Medical Education, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar
| | - Khalifa Bshesh
- Department of Medical Education, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar
| | - Isra Marei
- Department of Pharmacology, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar
| | - Kevin Ye
- Department of Biomedical Physiology & Kinesiology, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Hong Ding
- Department of Pharmacology, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar; Department of Medical Education, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar
| | - Ross MacDonald
- Distribution eLibrary, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar
| | - Morley D Hollenberg
- Department of Physiology & Pharmacology, a Cumming School of Medicine, University of Calgary, T2N 4N1, Canada
| | - Michael A Hill
- Dalton Cardiovascular Research Center, Department of Medical Pharmacology & Physiology, School of Medicine, University of Missouri, Columbia 65211, MO, USA
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5
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Sanchez-Álvarez NT, Bautista-Niño PK, Trejos-Suárez J, Serrano-Díaz NC. A model of metformin mitochondrial metabolism in metachromatic leukodystrophy: first description of human Schwann cells transfected with CRISPR-Cas9. Open Biol 2022; 12:210371. [PMID: 35857900 PMCID: PMC9256087 DOI: 10.1098/rsob.210371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Metachromatic leukodystrophy is a neurological lysosomal deposit disease that affects public health despite its low incidence in the population. Currently, few reports are available on pathophysiological events related to enzyme deficiencies and subsequent sulfatide accumulation. This research aims to examine the use of metformin as an alternative treatment to counteract these effects. This was evaluated in human Schwann cells (HSCs) transfected or non-transfected with CRISPR-Cas9, and later treated with sulfatides and metformin. This resulted in transfected HSCs showing a significant increase in cell reactive oxygen species (ROS) production when exposed to 100 µM sulfatides (p = 0.0007), compared to non-transfected HSCs. Sulfatides at concentrations of 10 to 100 µM affected mitochondrial bioenergetics in transfected HSCs. Moreover, these analyses showed that transfected cells showed a decrease in basal and maximal respiration rates after exposure to 100 µM sulfatide. However, maximal and normal mitochondrial respiratory capacity decreased in cells treated with both sulfatide and metformin. This study has provided valuable insights into bioenergetic and mitochondrial effects of sulfatides in HSCs for the first time. Treatment with metformin (500 µM) restored the metabolic activity of these cells and decreased ROS production.
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Affiliation(s)
- Nayibe Tatiana Sanchez-Álvarez
- Faculty of Medical and Health Sciences, Masira Institute for Biomedical Research, Universidad de Santander, Bucaramanga, Colombia,Faculty of Health, Phd in Biomedical Sciences, Universidad del Valle, Cali, Colombia,Research Center Floridablanca, Colombian Cardiovascular Foundation, FL, Colombia
| | | | - Juanita Trejos-Suárez
- Faculty of Medical and Health Sciences, Masira Institute for Biomedical Research, Universidad de Santander, Bucaramanga, Colombia
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Liu J, Zhu Z, Leung GKK. Erythrophagocytosis by Microglia/Macrophage in Intracerebral Hemorrhage: From Mechanisms to Translation. Front Cell Neurosci 2022; 16:818602. [PMID: 35237132 PMCID: PMC8882619 DOI: 10.3389/fncel.2022.818602] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/10/2022] [Indexed: 12/17/2022] Open
Abstract
Intracerebral hemorrhage (ICH) is a devastating condition characterized by hematoma related mass effect. Microglia/macrophage (M φ) are rapidly recruited in order to remove the red blood cells through erythrophagocytosis. Efficient erythrophagocytosis can detoxify hemolytic products and facilitate neurological recovery after ICH. The underlying mechanisms include modulation of inflammatory response and oxidative stress, among others. It is a dynamic process mediated by a cascade of signal transduction, including “find-me” signals, “eat-me” signals and a set of phagocytotic receptors-ligand pairs that may be exploited as therapeutic targets. This review summarizes mechanistic signaling pathways of erythrophagocytosis and highlights the potential of harnessing M φ-mediated phagocytosis for ICH treatment.
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Affiliation(s)
- Jiaxin Liu
- Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, Hong Kong SAR, China
| | - Zhiyuan Zhu
- Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, Hong Kong SAR, China
- Department of Functional Neurosurgery, The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, The Neurosurgery Institute of Guangdong Province, Guangzhou, China
- Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Gilberto Ka-Kit Leung
- Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, Hong Kong SAR, China
- *Correspondence: Gilberto Ka-Kit Leung,
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7
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Macroautophagy and Mitophagy in Neurodegenerative Disorders: Focus on Therapeutic Interventions. Biomedicines 2021; 9:biomedicines9111625. [PMID: 34829854 PMCID: PMC8615936 DOI: 10.3390/biomedicines9111625] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 02/06/2023] Open
Abstract
Macroautophagy, a quality control mechanism, is an evolutionarily conserved pathway of lysosomal degradation of protein aggregates, pathogens, and damaged organelles. As part of its vital homeostatic role, macroautophagy deregulation is associated with various human disorders, including neurodegenerative diseases. There are several lines of evidence that associate protein misfolding and mitochondrial dysfunction in the etiology of Alzheimer’s, Parkinson’s, and Huntington’s diseases. Macroautophagy has been implicated in the degradation of different protein aggregates such as Aβ, tau, alpha-synuclein (α-syn), and mutant huntingtin (mHtt) and in the clearance of dysfunctional mitochondria. Taking these into consideration, targeting autophagy might represent an effective therapeutic strategy to eliminate protein aggregates and to improve mitochondrial function in these disorders. The present review describes our current understanding on the role of macroautophagy in neurodegenerative disorders and focuses on possible strategies for its therapeutic modulation.
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8
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Llibre A, Dedicoat M, Burel JG, Demangel C, O’Shea MK, Mauro C. Host Immune-Metabolic Adaptations Upon Mycobacterial Infections and Associated Co-Morbidities. Front Immunol 2021; 12:747387. [PMID: 34630426 PMCID: PMC8495197 DOI: 10.3389/fimmu.2021.747387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/08/2021] [Indexed: 12/14/2022] Open
Abstract
Mycobacterial diseases are a major public health challenge. Their causative agents include, in order of impact, members of the Mycobacterium tuberculosis complex (causing tuberculosis), Mycobacterium leprae (causing leprosy), and non-tuberculous mycobacterial pathogens including Mycobacterium ulcerans. Macrophages are mycobacterial targets and they play an essential role in the host immune response to mycobacteria. This review aims to provide a comprehensive understanding of the immune-metabolic adaptations of the macrophage to mycobacterial infections. This metabolic rewiring involves changes in glycolysis and oxidative metabolism, as well as in the use of fatty acids and that of metals such as iron, zinc and copper. The macrophage metabolic adaptations result in changes in intracellular metabolites, which can post-translationally modify proteins including histones, with potential for shaping the epigenetic landscape. This review will also cover how critical tuberculosis co-morbidities such as smoking, diabetes and HIV infection shape host metabolic responses and impact disease outcome. Finally, we will explore how the immune-metabolic knowledge gained in the last decades can be harnessed towards the design of novel diagnostic and therapeutic tools, as well as vaccines.
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Affiliation(s)
- Alba Llibre
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Martin Dedicoat
- Department of Infectious Diseases, Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Julie G. Burel
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States
| | - Caroline Demangel
- Immunobiology of Infection Unit, Institut Pasteur, INSERM U1224, Paris, France
| | - Matthew K. O’Shea
- Department of Infectious Diseases, Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Claudio Mauro
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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Sfera A, Osorio C, Zapata Martín del Campo CM, Pereida S, Maurer S, Maldonado JC, Kozlakidis Z. Endothelial Senescence and Chronic Fatigue Syndrome, a COVID-19 Based Hypothesis. Front Cell Neurosci 2021; 15:673217. [PMID: 34248502 PMCID: PMC8267916 DOI: 10.3389/fncel.2021.673217] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome is a serious illness of unknown etiology, characterized by debilitating exhaustion, memory impairment, pain and sleep abnormalities. Viral infections are believed to initiate the pathogenesis of this syndrome although the definite proof remains elusive. With the unfolding of COVID-19 pandemic, the interest in this condition has resurfaced as excessive tiredness, a major complaint of patients infected with the SARS-CoV-2 virus, often lingers for a long time, resulting in disability, and poor life quality. In a previous article, we hypothesized that COVID-19-upregulated angiotensin II triggered premature endothelial cell senescence, disrupting the intestinal and blood brain barriers. Here, we hypothesize further that post-viral sequelae, including myalgic encephalomyelitis/chronic fatigue syndrome, are promoted by the gut microbes or toxin translocation from the gastrointestinal tract into other tissues, including the brain. This model is supported by the SARS-CoV-2 interaction with host proteins and bacterial lipopolysaccharide. Conversely, targeting microbial translocation and cellular senescence may ameliorate the symptoms of this disabling illness.
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Affiliation(s)
- Adonis Sfera
- Patton State Hospital, San Bernardino, CA, United States
| | | | | | | | - Steve Maurer
- Patton State Hospital, San Bernardino, CA, United States
| | - Jose Campo Maldonado
- Department of Internal Medicine, The University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Zisis Kozlakidis
- International Agency for Research on Cancer (IARC), Lyon, France
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Metformin inhibition of mitochondrial ATP and DNA synthesis abrogates NLRP3 inflammasome activation and pulmonary inflammation. Immunity 2021; 54:1463-1477.e11. [PMID: 34115964 PMCID: PMC8189765 DOI: 10.1016/j.immuni.2021.05.004] [Citation(s) in RCA: 183] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/30/2021] [Accepted: 05/05/2021] [Indexed: 12/15/2022]
Abstract
Acute respiratory distress syndrome (ARDS), an inflammatory condition with high mortality rates, is common in severe COVID-19, whose risk is reduced by metformin rather than other anti-diabetic medications. Given evidence of inflammasome assembly in post-mortem COVID-19 lungs, we asked whether and how metformin inhibits inflammasome activation and exerts its anti-inflammatory effect. We show that metformin inhibited NLRP3 inflammasome activation and interleukin (IL)-1β production in cultured and alveolar macrophages along with inflammasome-independent IL-6 secretion, thus attenuating lipopolysaccharide (LPS)- and SARS-CoV-2-induced ARDS. Metformin blocked LPS-induced ATP-dependent synthesis of the NLRP3 ligand mtDNA independently of AMP-activated protein kinase (AMPK) or NF-κB. Myeloid-specific ablation of LPS-induced cytidine monophosphate kinase 2 (CMPK2), which is rate limiting for mtDNA synthesis, reduced ARDS severity without a direct effect on IL-6. Thus, inhibition of ATP and mtDNA synthesis is sufficient for ARDS amelioration.
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11
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Chen Y, Zhao S, Fan Z, Li Z, Zhu Y, Shen T, Li K, Yan Y, Tian J, Liu Z, Zhang B. Metformin attenuates plaque-associated tau pathology and reduces amyloid-β burden in APP/PS1 mice. ALZHEIMERS RESEARCH & THERAPY 2021; 13:40. [PMID: 33563332 PMCID: PMC7871393 DOI: 10.1186/s13195-020-00761-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/23/2020] [Indexed: 12/22/2022]
Abstract
Background The neuropathological hallmarks of Alzheimer’s disease (AD) are amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs). The amyloid cascade theory is the leading hypothesis of AD pathology. Aβ deposition precedes the aggregation of tau pathology and Aβ pathology precipitates tau pathology. Evidence also indicates the reciprocal interactions between amyloid and tau pathology. However, the detailed relationship between amyloid and tau pathology in AD remains elusive. Metformin might have a positive effect on cognitive impairments. However, whether metformin can reduce AD-related pathologies is still unconclusive. Methods Brain extracts containing tau aggregates were unilaterally injected into the hippocampus and the overlying cerebral cortex of 9-month-old APPswe/PS1DE9 (APP/PS1) mice and age-matched wild-type (WT) mice. Metformin was administrated in the drinking water for 2 months. Aβ pathology, tau pathology, plaque-associated microgliosis, and autophagy marker were analyzed by immunohistochemical staining and immunofluorescence analysis 2 months after injection of proteopathic tau seeds. The effects of metformin on both pathologies were explored. Results We observed tau aggregates in dystrophic neurites surrounding Aβ plaques (NP tau) in the bilateral hippocampi and cortices of tau-injected APP/PS1 mice but not WT mice. Aβ plaques promoted the aggregation of NP tau pathology. Injection of proteopathic tau seeds exacerbated Aβ deposits and decreased the number of microglia around Aβ plaques in the hippocampus and cortex of APP/PS1 mice. Metformin ameliorated the microglial autophagy impairment, increased the number of microglia around Aβ plaques, promoted the phagocytosis of NP tau, and reduced Aβ load and NP tau pathology in APP/PS1 mice. Conclusion These findings indicate the existence of the crosstalk between amyloid and NP tau pathology. Metformin promoted the phagocytosis of pathological Aβ and tau proteins by enhancing microglial autophagy capability. It reduced Aβ deposits and limited the spreading of NP tau pathology in APP/PS1 mice, which exerts a beneficial effect on both pathologies.
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Affiliation(s)
- Yanxing Chen
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Shuai Zhao
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Ziqi Fan
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Zheyu Li
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Yueli Zhu
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.,Department of Geriatrics, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Ting Shen
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Kaicheng Li
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Yaping Yan
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Jun Tian
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Zhirong Liu
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Baorong Zhang
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
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12
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Qiao P, Ma J, Wang Y, Huang Z, Zou Q, Cai Z, Tang Y. Curcumin Prevents Neuroinflammation by Inducing Microglia to Transform into the M2-phenotype via CaMKKβ-dependent Activation of the AMP-Activated Protein Kinase Signal Pathway. Curr Alzheimer Res 2020; 17:735-752. [PMID: 33176649 DOI: 10.2174/1567205017666201111120919] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 07/03/2020] [Accepted: 09/08/2020] [Indexed: 01/13/2023]
Abstract
BACKGROUND Neuroinflammation plays an important role in the pathophysiological process of various neurodegenerative diseases. It is well known that curcumin has obvious anti-inflammatory effects in various neuroinflammation models. However, its effect on the modulation of microglial polarization is largely unknown. OBJECTIVE This study aimed to investigate whether curcumin changed microglia to an anti-inflammatory M2-phenotype by activating the AMP-activated protein kinase (AMPK) signaling pathway. METHODS LPS treatment was used to establish BV2 cells and primary microglia neuroinflammation models. The neuroinflammation mouse model was established by an intracerebroventricular (ICV) injection of lipopolysaccharide (LPS) in the lateral septal complex region of the brain. TNF-α was measured by ELISA, and cell viability was measured by Cell Counting Kit-8 (CCK-8). The expression of proinflammatory and anti-inflammatory cytokines was examined by Q-PCR and Western blot analysis. Phenotypic polarization of BV2 microglia was detected by immunofluorescence. RESULTS Curcumin enhanced AMPK activation in BV2 microglial cells in the presence and absence of LPS. Upon LPS stimulation, the addition of curcumin promoted M2 polarization of BV2 cells, as evidenced by suppressed M1 and the elevated M2 signature protein and gene expression. The effects of curcumin were inhibited by an AMPK inhibitor or AMPK knockdown. Calmodulin-dependent protein kinase kinase β (CaMKKβ) and liver kinase B1 (LKB1) are upstream kinases that activate AMPK. Curcumin can activate AMPK in Hela cells, which do not express LKB1. However, both the CaMKKβ inhibitor and siRNA blocked curcumin activation of AMPK in LPS-stimulated BV2 cells. Moreover, the CaMKKβ inhibitor and siRNA weaken the effect of curcumin suppression on M1 and enhancement of M2 protein and gene expression in LPS-stimulated BV2 cells. Finally, curcumin enhanced AMPK activation in the brain area where microglia were over-activated upon LPS stimulation in an in vivo neuroinflammation model. Moreover, curcumin also suppressed M1 and promoted M2 signature protein and gene expression in this in vivo model. CONCLUSION Curcumin enhances microglia M2 polarization via the CaMKKβ-dependent AMPK signaling pathway. Additionally, curcumin treatment was found to be neuroprotective and thus might be considered as a novel therapeutic agent to treat the neurodegenerative disease such as Alzheimer's disease, Parkinson's disease, etc.
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Affiliation(s)
- Peifeng Qiao
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing,
China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China,Department of Histology and Embryology, Chongqing Medical University, Chongqing, 400016, China
| | - Jingxi Ma
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing,
China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China
| | - Yangyang Wang
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing,
China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China
| | - Zhenting Huang
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing,
China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China
| | - Qian Zou
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing,
China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China
| | - Zhiyou Cai
- Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing,
China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, China
| | - Yong Tang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing, 400016, China
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13
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Lv J, Wang W, Zhu X, Xu X, Yan Q, Lu J, Shi X, Wang Z, Zhou J, Huang X, Wang J, Duan W, Shen X. DW14006 as a direct AMPKα1 activator improves pathology of AD model mice by regulating microglial phagocytosis and neuroinflammation. Brain Behav Immun 2020; 90:55-69. [PMID: 32739363 DOI: 10.1016/j.bbi.2020.07.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 07/21/2020] [Accepted: 07/27/2020] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is a progressively neurodegenerative disease with typical hallmarks of amyloid β (Aβ) plaque accumulation, neurofibrillary tangle (NFT) formation and neuronal death extension. In AD brain, activated microglia phagocytose Aβ and neuronal debris, but also aggravate inflammation stress by releasing inflammatory factors and cytotoxins. Improving microglia on Aβ catabolism and neuroinflammatory intervention is thus believed to be a promising therapeutic strategy for AD. AMP-activated protein kinase (AMPK) is highly expressed in microglia with AMPKα1 being tightly implicated in neuroinflammatory events. Since indirect AMPKα1 activators may cause side effects with undesired intracellular AMP/ATP ratio, we focused on direct AMPKα1 activator study by exploring its potential function in ameliorating AD-like pathology of AD model mice. Here, we reported that direct AMPKα1 activator DW14006 (2-(3-(7-chloro-6-(2'-hydroxy-[1,1'-biphenyl]-4-yl)-2-oxo-1,2-dihydroquinolin-3-yl)phenyl)acetic acid) effectively improved learning and memory impairments of APP/PS1 mice, and the underlying mechanisms have been intensively investigated. DW14006 reduced amyloid plaque deposition by promoting microglial o-Aβ42 phagocytosis and ameliorated innate immune response by polarizing microglia to an anti-inflammatory phenotype. It selectively enhanced microglial phagocytosis of o-Aβ42 by upgrading scavenger receptor CD36 through AMPKα1/PPARγ/CD36 signaling and suppressed inflammation by AMPKα1/IκB/NFκB signaling. Together, our work has detailed the crosstalk between AMPKα1 and microglia in AD model mice, and highlighted the potential of DW14006 in the treatment of AD.
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Affiliation(s)
- Jianlu Lv
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wei Wang
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China; University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China
| | - Xialin Zhu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xiaoju Xu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Qiuying Yan
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jian Lu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xiaofan Shi
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China; Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Zhengyu Wang
- Department of Medicinal Chemistry, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, China
| | - Jinpei Zhou
- Department of Medicinal Chemistry, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, China
| | - Xi Huang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jiaying Wang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Wenhu Duan
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China; University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.
| | - Xu Shen
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China.
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14
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El-Ghaiesh SH, Bahr HI, Ibrahiem AT, Ghorab D, Alomar SY, Farag NE, Zaitone SA. Metformin Protects From Rotenone-Induced Nigrostriatal Neuronal Death in Adult Mice by Activating AMPK-FOXO3 Signaling and Mitigation of Angiogenesis. Front Mol Neurosci 2020; 13:84. [PMID: 32625061 PMCID: PMC7314970 DOI: 10.3389/fnmol.2020.00084] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022] Open
Abstract
Parkinson’s disease (PD) is a neurodegenerative disease that affects substantia nigra dopamine neurons. Many studies have documented the role of oxidative stress and angiogenesis in the pathogenesis of PD. Metformin (MTF) is an antidiabetic medication and AMP-activated protein kinase (AMPK) regulator that has shown antioxidant and antiangiogenic properties in many disorders. The aim of this study is to investigate the neuroprotective effect of MTF in a mouse model of rotenone-prompted PD with a highlight on its influence on the AMPK/forkhead box transcription factor O3 (FOXO3) pathway and striatal angiogenesis. In the running study, PD was induced in mice using repeated doses of rotenone and concomitantly treated with MTF 100 or 200 mg/kg/day for 18 days. Rotarod and pole tests were used to examine the animals’ motor functionality. After that, animals were sacrificed, and brains were isolated and processed for immunohistochemical investigations or biochemical analyses. Oxidant stress and angiogenic markers were measured, including reduced glutathione, malondialdehyde, the nuclear factor erythroid 2–related factor 2 (Nrf2), hemoxygenase-1, thioredoxin, AMPK, FOXO3, and vascular endothelial growth factor (VEGF). Results indicated that MTF improved animals’ motor function, improved striatal glutathione, Nrf2, hemoxygenase-1, and thioredoxin. Furthermore, MTF upregulated AMPK-FOXO3 proteins and reduced VEGF and cleaved caspase 3. MTF also increased the number of tyrosine hydroxylase (TH)–stained neurons in the substantia nigra neurons and in striatal neuronal terminals. This study is the first to highlight that the neuroprotective role of MTF is mediated through activation of AMPK-FOXO3 signaling and inhibition of the proangiogenic factor, VEGF. Further studies are warranted to confirm this mechanism in other models of PD and neurodegenerative diseases.
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Affiliation(s)
- Sabah H El-Ghaiesh
- Department of Pharmacology, Faculty of Medicine, University of Tabuk, Tabuk, Saudi Arabia.,Department of Pharmacology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Hoda I Bahr
- Department of Biochemistry, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Afaf T Ibrahiem
- Department of Pathology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Doaa Ghorab
- Department of Pathology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Suliman Y Alomar
- Doping Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Noha E Farag
- Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.,Department of Physiology, College of Medicine, Taif University, Taif, Saudi Arabia
| | - Sawsan A Zaitone
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia
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15
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Lachmandas E, Eckold C, Böhme J, Koeken VACM, Marzuki MB, Blok B, Arts RJW, Chen J, Teng KWW, Ratter J, Smolders EJ, Van den Heuvel C, Stienstra R, Dockrell HM, Newell E, Netea MG, Singhal A, Cliff JM, Van Crevel R. Metformin Alters Human Host Responses to Mycobacterium tuberculosis in Healthy Subjects. J Infect Dis 2020; 220:139-150. [PMID: 30753544 PMCID: PMC6548897 DOI: 10.1093/infdis/jiz064] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 02/07/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Metformin, the most widely administered diabetes drug, has been proposed as a candidate adjunctive host-directed therapy for tuberculosis, but little is known about its effects on human host responses to Mycobacterium tuberculosis. METHODS We investigated in vitro and in vivo effects of metformin in humans. RESULTS Metformin added to peripheral blood mononuclear cells from healthy volunteers enhanced in vitro cellular metabolism while inhibiting the mammalian target of rapamycin targets p70S6K and 4EBP1, with decreased cytokine production and cellular proliferation and increased phagocytosis activity. Metformin administered to healthy human volunteers led to significant downregulation of genes involved in oxidative phosphorylation, mammalian target of rapamycin signaling, and type I interferon response pathways, particularly following stimulation with M. tuberculosis, and upregulation of genes involved in phagocytosis and reactive oxygen species production was increased. These in vivo effects were accompanied by a metformin-induced shift in myeloid cells from classical to nonclassical monocytes. At a functional level, metformin lowered ex vivo production of tumor necrosis factor α, interferon γ, and interleukin 1β but increased phagocytosis activity and reactive oxygen species production. CONCLUSION Metformin has a range of potentially beneficial effects on cellular metabolism, immune function, and gene transcription involved in innate host responses to M. tuberculosis.
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Affiliation(s)
- Ekta Lachmandas
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
| | - Clare Eckold
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Julia Böhme
- Singapore Immunology Network, Agency for Science, Technology, and Research
| | - Valerie A C M Koeken
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
| | | | - Bastiaan Blok
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
| | - Rob J W Arts
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
| | - Jinmiao Chen
- Singapore Immunology Network, Agency for Science, Technology, and Research
| | - Karen W W Teng
- Singapore Immunology Network, Agency for Science, Technology, and Research
| | - Jacqueline Ratter
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen.,Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands
| | - Elise J Smolders
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
| | - Corina Van den Heuvel
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
| | - Rinke Stienstra
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen.,Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands
| | - Hazel M Dockrell
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Evan Newell
- Singapore Immunology Network, Agency for Science, Technology, and Research
| | - Mihai G Netea
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen.,Human Genomics Laboratory, Craiova University of Medicine and Pharmacy, Romania
| | - Amit Singhal
- Singapore Immunology Network, Agency for Science, Technology, and Research.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Jacqueline M Cliff
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Reinout Van Crevel
- Department of Internal Medicine, Nijmegen.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen
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16
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Nie J, Jiang LS, Zhang Y, Tian Y, Li LS, Lu YL, Yang WJ, Shi JS. Dendrobium nobile Lindl. Alkaloids Decreases the Level of Intracellular β-Amyloid by Improving Impaired Autolysosomal Proteolysis in APP/PS1 Mice. Front Pharmacol 2018; 9:1479. [PMID: 30618767 PMCID: PMC6305391 DOI: 10.3389/fphar.2018.01479] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022] Open
Abstract
As the major degradation pathway for long-lived proteins and organelles, macroautophagy is a decisive factor for the survival and longevity of cells. The existing evidence indicates that the disruption of substrate proteolysis in autolysosomes is the main mechanism underlying autophagy failure in Alzheimer’s disease (AD). Thus, the restoration of normal lysosomal proteolysis and autophagy efficiency is a novel therapeutic strategy in the treatment of AD. In this study, 9-month-old APPswe/PS1ΔE9 transgenic (APP/PS1) mice were administered Dendrobium nobile Lindl. alkaloids (DNLA, 40 and 80 mg/kg) or Metformin (80 mg/kg), and age-matched wild-type mice were administered an isovolumic vehicle orally once a day for 4 months. The results demonstrated that DNLA significantly improved learning and memory function in APP/PS1 transgenic mice in the Morris water maze. Furthermore, DNLA could increase the expression of the v-ATPase A1 subunit to facilitate lysosomal acidification, prompt the dissociation of the cation independent-mannose-phosphate receptor from cathepsin (cat) D, promote the proteolytic maturation of cat D, increase the degradation of accumulated autophagic vacuoles (AVs) and β-amyloid (Aβ) contained in the AVs, and alleviate neuronal and synaptic injury. These findings demonstrate that DNLA improves learning and memory function in APP/PS1 mice, and the mechanisms appear to be due to the promotion of intracellular Aβ degradation by increasing the protein level of v-ATPase A1 and then improving autolysosomal acidification and proteolysis.
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Affiliation(s)
- Jing Nie
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Lin-Shan Jiang
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yu Zhang
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yong Tian
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Li-Sheng Li
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yan-Liu Lu
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Wen-Jin Yang
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Jing-Shan Shi
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
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17
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Tayara K, Espinosa-Oliva AM, García-Domínguez I, Ismaiel AA, Boza-Serrano A, Deierborg T, Machado A, Herrera AJ, Venero JL, de Pablos RM. Divergent Effects of Metformin on an Inflammatory Model of Parkinson's Disease. Front Cell Neurosci 2018; 12:440. [PMID: 30519161 PMCID: PMC6258993 DOI: 10.3389/fncel.2018.00440] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 11/05/2018] [Indexed: 01/08/2023] Open
Abstract
The oral antidiabetic drug metformin is known to exhibit anti-inflammatory properties through activation of AMP kinase, thus protecting various brain tissues as cortical neurons, for example. However, the effect of metformin on the substantia nigra (SN), the main structure affected in Parkinson’s disease (PD), has not yet been studied in depth. Inflammation is a key feature of PD and it may play a central role in the neurodegeneration that takes place in this disorder. The aim of this work was to determine the effect of metformin on the microglial activation of the SN of rats using the animal model of PD based on the injection of the pro-inflammogen lipopolysaccharide (LPS). In vivo and in vitro experiments were conducted to study the activation of microglia at both the cellular and molecular levels. Our results indicate that metformin overall inhibits microglia activation measured by OX-6 (MHCII marker), IKKβ (pro-inflammatory marker) and arginase (anti-inflammatory marker) immunoreactivity. In addition, qPCR experiments reveal that metformin treatment minimizes the expression levels of several pro- and anti-inflammatory cytokines. Mechanistically, the drug decreases the phosphorylated forms of mitogen-activated protein kinases (MAPKs) as well as ROS generation through the inhibition of the NADPH oxidase enzyme. However, metformin treatment fails to protect the dopaminergic neurons of SN in response to intranigral LPS. These findings suggest that metformin could have both beneficial and harmful pharmacological effects and raise the question about the potential use of metformin for the prevention and treatment of PD.
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Affiliation(s)
- Khadija Tayara
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Ana M Espinosa-Oliva
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Irene García-Domínguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Afrah Abdul Ismaiel
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Antonio Boza-Serrano
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Tomas Deierborg
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Alberto Machado
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Antonio J Herrera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - José L Venero
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Rocío M de Pablos
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
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18
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STAT3 associates with vacuolar H +-ATPase and regulates cytosolic and lysosomal pH. Cell Res 2018; 28:996-1012. [PMID: 30127373 PMCID: PMC6170402 DOI: 10.1038/s41422-018-0080-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 06/28/2018] [Accepted: 07/16/2018] [Indexed: 12/02/2022] Open
Abstract
Dysregulated intracellular pH is emerging as a hallmark of cancer. In spite of their acidic environment and increased acid production, cancer cells maintain alkaline intracellular pH that promotes cancer progression by inhibiting apoptosis and increasing glycolysis, cell growth, migration, and invasion. Here we identify signal transducer and activator of transcription-3 (STAT3) as a key factor in the preservation of alkaline cytosol. STAT3 associates with the vacuolar H+-ATPase in a coiled-coil domain-dependent manner and increases its activity in living cells and in vitro. Accordingly, STAT3 depletion disrupts intracellular proton equilibrium by decreasing cytosolic pH and increasing lysosomal pH, respectively. This dysregulation can be reverted by reconstitution with wild-type STAT3 or STAT3 mutants unable to activate target genes (Tyr705Phe and DNA-binding mutant) or to regulate mitochondrial respiration (Ser727Ala). Upon cytosolic acidification, STAT3 is transcriptionally inactivated and further recruited to lysosomal membranes to reestablish intracellular proton equilibrium. These data reveal STAT3 as a regulator of intracellular pH and, vice versa, intracellular pH as a regulator of STAT3 localization and activity.
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19
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Metformin reduces the relapse rate of tuberculosis patients with diabetes mellitus: experiences from 3-year follow-up. Eur J Clin Microbiol Infect Dis 2018; 37:1259-1263. [DOI: 10.1007/s10096-018-3242-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 03/23/2018] [Indexed: 01/17/2023]
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20
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Ou Z, Kong X, Sun X, He X, Zhang L, Gong Z, Huang J, Xu B, Long D, Li J, Li Q, Xu L, Xuan A. Metformin treatment prevents amyloid plaque deposition and memory impairment in APP/PS1 mice. Brain Behav Immun 2018; 69:351-363. [PMID: 29253574 DOI: 10.1016/j.bbi.2017.12.009] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/04/2017] [Accepted: 12/14/2017] [Indexed: 12/18/2022] Open
Abstract
Alzheimer'sdisease(AD) is characterized by deposition of amyloid-β (Aβ)plaques, neurofibrillary tangles, andneuronal loss, accompaniedbyneuroinflammation. Neuroinflammatoryprocesses are thought to contribute toAD pathophysiology. Metformin has been reported to have anti-inflammatory efficacy. However, whether metformin is responsible for the anti-neuroinflammationand neuroprotection on APPswe/PS1ΔE9 (APP/PS1) mice remains unclear. Here we showed that metformin attenuated spatial memory deficit, neuron loss in the hippocampus and enhanced neurogenesis in APP/PS1 mice. In addition, metformin administration decreased amyloid-β (Aβ)plaque load and chronic inflammation (activated microglia and astrocytes as well as pro-inflammatory mediators) in the hippocampus and cortex. Further study demonstrated that treatment with metformin enhanced cerebral AMPK activation. Meanwhile, metformin notably suppressed the activation of P65 NF-κB, mTOR and S6K, reduced Bace1 protein expression. Our data suggest that metformin can exert functional recovery of memory deficits and neuroprotective effect on APP/PS1 mice via triggering neurogenesis and anti-inflammation mediated by regulating AMPK/mTOR/S6K/Bace1 and AMPK/P65 NF-κB signaling pathways in the hippocampus, which may contribute to improvement in neurological deficits.
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Affiliation(s)
- Zhenri Ou
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Xuejian Kong
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Xiangdong Sun
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Xiaosong He
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Le Zhang
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Zhuo Gong
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Jingyi Huang
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Biao Xu
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Dahong Long
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Jianhua Li
- Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou 511436, China
| | - Qingqing Li
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Liping Xu
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Aiguo Xuan
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Department of Neurology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China.
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21
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Fang M, Jiang H, Ye L, Cai C, Hu Y, Pan S, Li P, Xiao J, Lin Z. Metformin treatment after the hypoxia-ischemia attenuates brain injury in newborn rats. Oncotarget 2017; 8:75308-75325. [PMID: 29088867 PMCID: PMC5650422 DOI: 10.18632/oncotarget.20779] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/30/2017] [Indexed: 12/15/2022] Open
Abstract
Neonatal hypoxic-ischemic (HI) brain injury is a devastating disease that often leads to death and detrimental neurological deficits. The present study was designed to evaluate the ability of metformin to provide neuroprotection in a model of neonatal hypoxic-ischemic brain injury and to study the associated molecular mechanisms behind these protective effects. Here, we found that metformin treatment remarkably attenuated brain infarct volumes and brain edema at 24 h after HI injury, and the neuroprotection of metformin was associated with inhibition of neuronal apoptosis, suppression of the neuroinflammation and amelioration of the blood brain barrier breakdown. Additionally, metformin treatment conferred long-term protective against brain damage at 7 d after HI injury. Our study indicates that metformin treatment protects against neonatal hypoxic-ischemic brain injury and thus has potential as a therapy for this disease.
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Affiliation(s)
- Mingchu Fang
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Huai Jiang
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Lixia Ye
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Chenchen Cai
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yingying Hu
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Shulin Pan
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Peijun Li
- Center for Neuroscience Research, Children's National Health System, Washington, DC 20010, United States
| | - Jian Xiao
- Molecular Pharmacology Research Center, School of Pharmacy, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Zhenlang Lin
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
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22
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Hohnholt MC, Blumrich EM, Waagepetersen HS, Dringen R. The antidiabetic drug metformin decreases mitochondrial respiration and tricarboxylic acid cycle activity in cultured primary rat astrocytes. J Neurosci Res 2017; 95:2307-2320. [PMID: 28316081 DOI: 10.1002/jnr.24050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 12/18/2022]
Abstract
Metformin is an antidiabetic drug that is used daily by millions of patients worldwide. Metformin is able to cross the blood-brain barrier and has recently been shown to increase glucose consumption and lactate release in cultured astrocytes. However, potential effects of metformin on mitochondrial tricarboxylic acid (TCA) cycle metabolism in astrocytes are unknown. We investigated this by mapping 13 C labeling in TCA cycle intermediates and corresponding amino acids after incubation of primary rat astrocytes with [U-13 C]glucose. The presence of metformin did not compromise the viability of cultured astrocytes during 4 hr of incubation, but almost doubled cellular glucose consumption and lactate release. Compared with control cells, the presence of metformin dramatically lowered the molecular 13 C carbon labeling (MCL) of the cellular TCA cycle intermediates citrate, α-ketoglutarate, succinate, fumarate, and malate, as well as the MCL of the TCA cycle intermediate-derived amino acids glutamate, glutamine, and aspartate. In addition to the total molecular 13 C labeling, analysis of the individual isotopomers of TCA cycle intermediates confirmed a severe decline in labeling and a significant lowering in TCA cycling ratio in metformin-treated astrocytes. Finally, the oxygen consumption of mitochondria isolated from metformin-treated astrocytes was drastically reduced in the presence of complex I substrates, but not of complex II substrates. These data demonstrate that exposure to metformin strongly impairs complex I-mediated mitochondrial respiration in astrocytes, which is likely to cause the observed decrease in labeling of mitochondrial TCA cycle intermediates and the stimulation of glycolytic lactate production. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Michaela C Hohnholt
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Eva-Maria Blumrich
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany.,Centre for Environmental Research and Sustainable Technology, Bremen, Germany
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Ralf Dringen
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany.,Centre for Environmental Research and Sustainable Technology, Bremen, Germany
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23
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Restrepo BI. Metformin: Candidate host-directed therapy for tuberculosis in diabetes and non-diabetes patients. Tuberculosis (Edinb) 2016; 101S:S69-S72. [PMID: 27720378 DOI: 10.1016/j.tube.2016.09.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Despite major advances in tuberculosis (TB) control, TB continues to be a leading cause of death worldwide. The discovery of new anti-TB treatment drugs and regimens that target drug-sensitive and drug-resistant TB are being complemented with a search for adjunct host-directed therapies that synergize for Mycobacterium tuberculosis (Mtb) elimination. The goal of host-directed therapies is to boost immune mechanisms that diminish excess inflammation to reduce lung tissue damage and limit Mtb growth. Metformin is the most commonly-used medication for type 2 diabetes, and a candidate for host-directed therapy for TB. Preliminary data suggests metformin may be beneficial for TB control by reducing the deleterious inflammation associated with immune pathology and enhancing the anti-mycobacterial activity of immune cells. In this review I summarize current findings, knowledge gaps and the potential benefits as well as points of caution for using metformin as adjunct therapy for TB in patients with and without type 2 diabetes.
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Affiliation(s)
- Blanca I Restrepo
- UTHealth Houston, Department of Epidemiology, School of Public Health at Brownsville, 80 Fort Brown, SPH Bldg, Brownsville, TX 78520, USA.
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24
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Knockdown of GSK3β increases basal autophagy and AMPK signalling in nutrient-laden human aortic endothelial cells. Biosci Rep 2016; 36:BSR20160174. [PMID: 27534430 PMCID: PMC5025810 DOI: 10.1042/bsr20160174] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/14/2016] [Indexed: 12/28/2022] Open
Abstract
Suppression of the enzyme glycogen synthase kinase 3β (GSK3β) increases both the turnover of damaged cellular material and the activity of the enzyme AMP-activated protein kinase (AMPK) to potentially attenuate the damage inflicted by excess sugar and fat on blood vessels. High concentrations of glucose and palmitate increase endothelial cell inflammation and apoptosis, events that often precede atherogenesis. They may do so by decreasing basal autophagy and AMP-activated protein kinase (AMPK) activity, although the mechanisms by which this occurs are not clear. Decreased function of the lysosome, an organelle required for autophagy and AMPK, have been associated with hyperactivity of glycogen synthase kinase 3β (GSK3β). To determine whether GSK3β affects nutrient-induced changes in autophagy and AMPK activity, we used a primary human aortic endothelial cell (HAEC) model of type 2 diabetes that we had previously characterized with impaired AMPK activity and autophagy [Weikel et al. (2015) Am. J. Phys. Cell Physiol. 308, C249–C263]. Presently, we found that incubation of HAECs with excess nutrients (25 mM glucose and 0.4 mM palmitate) increased GSK3β activity and impaired lysosome acidification. Suppression of GSK3β in these cells by treatment with a chemical inhibitor or overexpression of kinase-dead GSK3β attenuated these lysosomal changes. Under control and excess nutrient conditions, knockdown of GSK3β increased autophagosome formation, forkhead box protein O1 (FOXO1) activity and AMPK signalling and decreased Akt signalling. Similar changes in autophagy, AMPK and Akt signalling were observed in aortas from mice treated with the GSK3β inhibitor CHIR 99021. Thus, increasing basal autophagy and AMPK activity by inhibiting GSK3β may be an effective strategy in the setting of hyperglycaemia and dyslipidaemia for restoring endothelial cell health and reducing atherogenesis.
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25
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Weikel KA, Ruderman NB, Cacicedo JM. Unraveling the actions of AMP-activated protein kinase in metabolic diseases: Systemic to molecular insights. Metabolism 2016; 65:634-645. [PMID: 27085772 PMCID: PMC4834453 DOI: 10.1016/j.metabol.2016.01.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 01/08/2016] [Accepted: 01/09/2016] [Indexed: 12/13/2022]
Abstract
AMP-activated protein kinase (AMPK) plays a critical role both in sensing and regulating cellular energy state. In experimental animals, its activation has been shown to reduce the risk of obesity and diabetes-related co-morbidities such as insulin resistance, the metabolic syndrome and atherosclerotic cardiovascular disease. However, in humans, AMPK activation alone often does not completely resolve these conditions. Thus, an improved understanding of AMPK action and regulation in metabolic and other diseases is needed. Herein, we provide a brief description of the enzymatic regulation of AMPK and review its role in maintaining energy homeostasis. We then discuss tissue-specific actions of AMPK that become distorted during such conditions as obesity, type 2 diabetes and certain cancers. Finally, we explore recent findings regarding the interactions of AMPK with mammalian target of rapamycin complex 1 and the lysosome and discuss how changes in these relationships during overnutrition may lead to AMPK dysfunction. A more thorough understanding of AMPK's molecular interactions during diseases of overnutrition may provide key insights for the development of AMPK-based combinatorial treatments for metabolic disease.
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Affiliation(s)
- Karen A Weikel
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA, 02118, USA.
| | - Neil B Ruderman
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA, 02118, USA
| | - José M Cacicedo
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA, 02118, USA
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26
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Liu Z, Bone N, Jiang S, Park DW, Tadie JM, Deshane J, Rodriguez CA, Pittet JF, Abraham E, Zmijewski JW. AMP-Activated Protein Kinase and Glycogen Synthase Kinase 3β Modulate the Severity of Sepsis-Induced Lung Injury. Mol Med 2016; 21:937-950. [PMID: 26650187 PMCID: PMC4818252 DOI: 10.2119/molmed.2015.00198] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/27/2015] [Indexed: 12/29/2022] Open
Abstract
Alterations in metabolic and bioenergetic homeostasis contribute to sepsis-mediated organ injury. However, how AMP-activated protein kinase (AMPK), a major sensor and regulator of energy expenditure and production, affects development of organ injury and loss of innate capacity during polymicrobial sepsis remains unclear. In the present experiments, we found that cross-talk between the AMPK and GSK3β signaling pathways controls chemotaxis and the ability of neutrophils and macrophages to kill bacteria ex vivo. In mice with polymicrobial abdominal sepsis or more severe sepsis induced by the combination of hemorrhage and intraabdominal infection, administration of the AMPK activator metformin or the GSK3β inhibitor SB216763 reduced the severity of acute lung injury (ALI). Improved survival in metformin-treated septic mice was correlated with preservation of mitochondrial complex V (ATP synthase) function and increased amounts of ETC complex III and IV. Although immunosuppression is a consequence of sepsis, metformin effectively increased innate immune capacity to eradicate P. aeruginosa in the lungs of septic mice. We also found that AMPK activation diminished accumulation of the immunosuppressive transcriptional factor HIF-1α as well as the development of endotoxin tolerance in LPS-treated macrophages. Furthermore, AMPK-dependent preservation of mitochondrial membrane potential also prevented LPS-mediated dysfunction of neutrophil chemotaxis. These results indicate that AMPK activation reduces the severity of polymicrobial sepsis-induced lung injury and prevents the development of sepsis-associated immunosuppression.
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Affiliation(s)
- Zhongyu Liu
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Nathaniel Bone
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Shaoning Jiang
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Dae Won Park
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jean-Marc Tadie
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jessy Deshane
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Cilina Ann Rodriguez
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jean-Francois Pittet
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Edward Abraham
- Office of the Dean, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Jaroslaw W Zmijewski
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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27
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Bułdak Ł, Łabuzek K, Bułdak RJ, Machnik G, Bołdys A, Basiak M, Bogusław O. Metformin reduces the expression of NADPH oxidase and increases the expression of antioxidative enzymes in human monocytes/macrophages cultured in vitro. Exp Ther Med 2016; 11:1095-1103. [PMID: 26998043 DOI: 10.3892/etm.2016.2977] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 09/25/2015] [Indexed: 01/08/2023] Open
Abstract
The treatment of diabetes and its complications is a key challenge for healthcare professionals. Accelerated atherosclerosis is associated with progressive diabetes, and it has been indicated that macrophages serve a crucial function in this process. Currently, the first-line treatment of diabetes is based on metformin, which is an inducer of AMP-activated protein kinase (AMPK) and belongs to the biguanide class of pharmaceuticals. It has been previously demonstrated that metformin exhibits more than just hypoglycemic effects. Therefore, the aim of the present study was to investigate the in vitro impact of metformin on cell viability and the expression levels of nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase (p22phox), a major enzyme in reactive oxygen species generation, and the three antioxidative enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in monocytes/macrophages derived from 10 healthy volunteers. The effects of metformin were observed in the presence or absence of lipopolysaccharide (LPS), which was administered to induce oxidative stress. Furthermore, certain cells were treated with compound C, an inhibitor of AMPK, in order to determine the mechanistic role played by AMPK in the oxidative changes in the macrophages. Cell viability was evaluated using trypan blue and MTT assays. The mRNA and protein expression levels of p22phox and the various antioxidative enzymes were determined using polymerase chain reaction and western blot analysis, respectively. The results indicated that metformin, predominantly in LPS-pretreated monocytes/macrophages, reduced the expression levels of p22phox and increased those of SOD and GPx, but had only a minor effect on CAT levels. Therefore, metformin appears to alter the oxidative status of macrophages toward increasingly antioxidative activity, which may account for the pleiotropic effects observed during metformin treatment.
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Affiliation(s)
- Łukasz Bułdak
- Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland
| | - Krzysztof Łabuzek
- Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland
| | - Rafał Jakub Bułdak
- Department of Physiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze 41-808, Poland
| | - Grzegorz Machnik
- Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland
| | - Aleksandra Bołdys
- Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland
| | - Marcin Basiak
- Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland
| | - Okopień Bogusław
- Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland
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28
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Chauss D, Brennan LA, Bakina O, Kantorow M. Integrin αVβ5-mediated Removal of Apoptotic Cell Debris by the Eye Lens and Its Inhibition by UV Light Exposure. J Biol Chem 2015; 290:30253-66. [PMID: 26527683 DOI: 10.1074/jbc.m115.688390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Indexed: 12/31/2022] Open
Abstract
Accumulation of apoptotic material is toxic and associated with cataract and other disease states. Identification of mechanisms that prevent accumulation of apoptotic debris is important for establishing the etiology of these diseases. The ocular lens is routinely assaulted by UV light that causes lens cell apoptosis and is associated with cataract formation. To date, no molecular mechanism for removal of toxic apoptotic debris has been identified in the lens. Vesicular debris within lens cells exposed to UV light has been observed raising speculation that lens cells themselves could act as phagocytes to remove toxic apoptotic debris. However, phagocytosis has not been confirmed as a function of the intact eye lens, and no mechanism for lens phagocytosis has been established. Here, we demonstrate that the eye lens is capable of phagocytizing extracellular lens cell debris. Using high throughput RNA sequencing and bioinformatics analysis, we establish that lens epithelial cells express members of the integrin αVβ5-mediated phagocytosis pathway and that internalized cell debris co-localizes with αVβ5 and with RAB7 and Rab-interacting lysosomal protein that are required for phagosome maturation and fusion with lysosomes. We demonstrate that the αVβ5 receptor is required for lens epithelial cell phagocytosis and that UV light treatment of lens epithelial cells results in damage to the αVβ5 receptor with concomitant loss of phagocytosis. These data suggest that loss of αVβ5-mediated phagocytosis by the eye lens could result in accumulation of toxic cell debris that could contribute to UV light-induced cataract formation.
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Affiliation(s)
- Daniel Chauss
- From the Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Lisa A Brennan
- From the Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Olga Bakina
- From the Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Marc Kantorow
- From the Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
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29
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Zhou X, Cao Y, Ao G, Hu L, Liu H, Wu J, Wang X, Jin M, Zheng S, Zhen X, Alkayed NJ, Jia J, Cheng J. CaMKKβ-dependent activation of AMP-activated protein kinase is critical to suppressive effects of hydrogen sulfide on neuroinflammation. Antioxid Redox Signal 2014; 21:1741-58. [PMID: 24624937 PMCID: PMC5695757 DOI: 10.1089/ars.2013.5587] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS The manner in which hydrogen sulfide (H2S) suppresses neuroinflammation is poorly understood. We investigated whether H2S polarized microglia to an anti-inflammatory (M2) phenotype by activating AMP-activated protein kinase (AMPK). RESULTS Three structurally unrelated H2S donors (5-(4-hydroxyphenyl)-3H-1,2-dithiocyclopentene-3-thione [ADT-OH], (p-methoxyphenyl) morpholino-phosphinodithioic acid [GYY4137], and sodium hydrosulfide [NaHS]) enhanced AMPK activation in BV2 microglial cells in the presence and absence of lipopolysaccharide (LPS). The overexpression of the H2S synthase cystathionine β-synthase (CBS) in BV2 cells enhanced endogenous H2S production and AMPK activation regardless of LPS stimulation. On LPS stimulation, overexpression of both ADT-OH and CBS promoted M2 polarization of BV2 cells, as evidenced by suppressed M1 and elevated M2 signature gene expression. The promoting effects of ADT-OH on M2 polarization were attenuated by an AMPK inhibitor or AMPK knockdown. Liver kinase B1 (LKB1) and calmodulin-dependent protein kinase kinase β (CaMKKβ) are upstream kinases that activate AMPK. ADT-OH activated AMPK in Hela cells lacking LKB1. In contrast, both the CaMKKβ inhibitor and siRNA abolished ADT-OH activation of AMPK in LPS-stimulated BV2 cells. Moreover, the CaMKKβ inhibitor and siRNA blunted ADT-OH suppression on M1 gene expression and enhancement of M2 gene expression in LPS-stimulated BV2 cells. Moreover, ADT-OH promoted M2 polarization of primary microglia in an AMPK activation- and CaMKKβ-dependent manner. Finally, in an LPS-induced in vivo neuroinflammation model, both ADT-OH and NaHS enhanced AMPK activation in the brain area where microglia were over-activated on LPS stimulation. Furthermore, ADT-OH suppressed M1 and promoted M2 gene expression in this in vivo model. INNOVATION AND CONCLUSION CaMKKβ-dependent AMPK activation is an unrecognized mechanism underlying H2S suppression on neuroinflammation.
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Affiliation(s)
- Xiaomei Zhou
- 1 Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University , Suzhou, China
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30
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Cho MH, Cho K, Kang HJ, Jeon EY, Kim HS, Kwon HJ, Kim HM, Kim DH, Yoon SY. Autophagy in microglia degrades extracellular β-amyloid fibrils and regulates the NLRP3 inflammasome. Autophagy 2014; 10:1761-75. [PMID: 25126727 DOI: 10.4161/auto.29647] [Citation(s) in RCA: 290] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Accumulation of β-amyloid (Aβ) and resultant inflammation are critical pathological features of Alzheimer disease (AD). Microglia, a primary immune cell in brain, ingests and degrades extracellular Aβ fibrils via the lysosomal system. Autophagy is a catabolic process that degrades native cellular components, however, the role of autophagy in Aβ degradation by microglia and its effects on AD are unknown. Here we demonstrate a novel role for autophagy in the clearance of extracellular Aβ fibrils by microglia and in the regulation of the Aβ-induced NLRP3 (NLR family, pyrin domain containing 3) inflammasome using microglia specific atg7 knockout mice and cell cultures. We found in microglial cultures that Aβ interacts with MAP1LC3B-II via OPTN/optineurin and is degraded by an autophagic process mediated by the PRKAA1 pathway. We anticipate that enhancing microglial autophagy may be a promising new therapeutic strategy for AD.
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Affiliation(s)
- Mi-Hyang Cho
- Alzheimer Disease Experts Lab (ADEL); Asan Institute of Life Sciences; Asan Medical Center; University of Ulsan College of Medicine; Seoul, Korea; Department of Anatomy and Cell Biology; University of Ulsan College of Medicine; Seoul, Korea; Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea
| | - Kwangmin Cho
- Alzheimer Disease Experts Lab (ADEL); Asan Institute of Life Sciences; Asan Medical Center; University of Ulsan College of Medicine; Seoul, Korea; Department of Anatomy and Cell Biology; University of Ulsan College of Medicine; Seoul, Korea; Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea
| | - Hoe-Jin Kang
- Alzheimer Disease Experts Lab (ADEL); Asan Institute of Life Sciences; Asan Medical Center; University of Ulsan College of Medicine; Seoul, Korea; Department of Anatomy and Cell Biology; University of Ulsan College of Medicine; Seoul, Korea; Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea
| | - Eun-Young Jeon
- Alzheimer Disease Experts Lab (ADEL); Asan Institute of Life Sciences; Asan Medical Center; University of Ulsan College of Medicine; Seoul, Korea; Department of Anatomy and Cell Biology; University of Ulsan College of Medicine; Seoul, Korea; Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea
| | - Hun-Sik Kim
- Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea; Department of Medicine; Graduate School; University of Ulsan College of Medicine; Seoul, Korea
| | - Hyung-Joon Kwon
- Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Department of Medicine; Graduate School; University of Ulsan College of Medicine; Seoul, Korea
| | - Hong-Mi Kim
- Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Department of Medicine; Graduate School; University of Ulsan College of Medicine; Seoul, Korea
| | - Dong-Hou Kim
- Alzheimer Disease Experts Lab (ADEL); Asan Institute of Life Sciences; Asan Medical Center; University of Ulsan College of Medicine; Seoul, Korea; Department of Anatomy and Cell Biology; University of Ulsan College of Medicine; Seoul, Korea; Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea
| | - Seung-Yong Yoon
- Alzheimer Disease Experts Lab (ADEL); Asan Institute of Life Sciences; Asan Medical Center; University of Ulsan College of Medicine; Seoul, Korea; Department of Anatomy and Cell Biology; University of Ulsan College of Medicine; Seoul, Korea; Bio-Medical Institute of Technology (BMIT); University of Ulsan College of Medicine; Seoul, Korea; Cell Dysfunction Research Center (CDRC); University of Ulsan College of Medicine; Seoul, Korea
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31
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Restrepo BI, Twahirwa M, Rahbar MH, Schlesinger LS. Phagocytosis via complement or Fc-gamma receptors is compromised in monocytes from type 2 diabetes patients with chronic hyperglycemia. PLoS One 2014; 9:e92977. [PMID: 24671137 PMCID: PMC3966862 DOI: 10.1371/journal.pone.0092977] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/27/2014] [Indexed: 02/07/2023] Open
Abstract
Type 2 diabetes patients (DM2) have a higher risk of tuberculosis (TB) that may be attributed to functional defects in their mononuclear phagocytes given the critical role of these cells in Mycobacterium tuberculosis containment. Our previous findings suggest that monocytes from DM2 have reduced association with serum-opsonized M. tuberculosis. To determine if this alteration is due to defects in phagocytosis via complement or Fc-gamma receptors (FcγRs), in this study we evaluated the uptake of sheep red blood cells coated with IgG or complement, respectively, by monocytes from individuals with and without DM2. We found that chronic hyperglycemia was significantly associated with reduced phagocytosis via either receptor by univariable and multivariable analyses. This defect was independent of host serum opsonins and flow cytometry data indicated this was not attributed to reduced expression of these phagocytic receptors on DM2 monocytes. The positive correlation between both pathways (R = 0.64; p = 0.003) indicate that monocytes from individuals with chronic hyperglycemia have a defect in the two predominant phagocytic pathways of these cells. Given that phagocytosis is linked to activation of effector mechanisms for bacterial killing, it is likely that this defect is one factor contributing to the higher susceptibility of DM2 patients to pathogens like M. tuberculosis.
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Affiliation(s)
- Blanca I Restrepo
- Division of Epidemiology, UTHealth Houston, School of Public Health at Brownsville, Brownsville, Texas, United States of America
| | - Marcel Twahirwa
- Joslin Diabetes Center-Doctors Hospital at Renaissance, Edinburg, Texas, United States of America
| | - Mohammad H Rahbar
- Division of Clinical and Translational Sciences, Department of Internal Medicine, Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Larry S Schlesinger
- Center for Microbial Interface Biology and Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
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Venna VR, Li J, Hammond MD, Mancini NS, McCullough LD. Chronic metformin treatment improves post-stroke angiogenesis and recovery after experimental stroke. Eur J Neurosci 2014; 39:2129-38. [PMID: 24649970 DOI: 10.1111/ejn.12556] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/09/2014] [Accepted: 02/12/2014] [Indexed: 02/06/2023]
Abstract
Metformin is currently the first-line treatment drug for type 2 diabetes. Metformin is a well-known activator of AMP-activated protein kinase (AMPK). In experimental studies, metformin has been shown to exert direct vascular effects by increasing vascular endothelial growth factor expression and improving microvascular density. As stroke is the leading cause of long-term disability and angiogenesis is implicated as an important mechanism in functional recovery, we hypothesized that chronic metformin treatment would improve post-stroke functional recovery by enhancing functional microvascular density. For this study, C57BL/6N male mice were subjected to a 60-min middle cerebral artery occlusion, and were given 50 mg/kg/day metformin beginning 24 h post-stroke for 3 weeks. Behavioral recovery was assessed using adhesive-tape removal and the apomorphine-induced turning test. The role of angiogenesis was assessed by counting vessel branch points from fluorescein-conjugated lectin-perfused brain sections. Importantly even if metformin treatment was initiated 24 h after injury it enhanced recovery and significantly improved stroke-induced behavioral deficits. This recovery occurred in parallel with enhanced angiogenesis and with restoration of endogenous cerebral dopaminergic tone and revascularization of ischemic tissue. We assessed if the effects on recovery and angiogenesis were mediated by AMPK. When tested in AMPK α-2 knockout mice, we found that metformin treatment did not have the same beneficial effects on recovery and angiogenesis, suggesting that metformin-induced angiogenic effects are mediated by AMPK. The results from this study suggest that metformin mediates post-stroke recovery by enhancing angiogenesis, and these effects are mediated by AMPK signaling.
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Affiliation(s)
- Venugopal R Venna
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
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Shin YH, Chung HJ, Park C, Jung J, Jeong NY. Adenosine 5'-triphosphate (ATP) inhibits schwann cell demyelination during Wallerian degeneration. Cell Mol Neurobiol 2013; 34:361-8. [PMID: 24363123 DOI: 10.1007/s10571-013-0020-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
Adenosine 5'-triphosphate (ATP) is implicated in intercellular communication as a neurotransmitter in the peripheral nervous system. In addition, ATP is known as lysosomal exocytosis activator. In this study, we investigated the role of extracellular ATP on demyelination during Wallerian degeneration (WD) using ex vivo and in vivo nerve degeneration models. We found that extracellular ATP inhibited myelin fragmentation and axonal degradation during WD. Furthermore, metformin and chlorpromazine, lysosomal exocytosis antagonists blocked the effect of ATP on the inhibition of demyelination. Thus, these findings indicate that ATP-induced-lysosomal exocytosis may be involved in demyelination during WD.
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Affiliation(s)
- Youn Ho Shin
- Department of Anatomy and Neurobiology, School of Medicine, Biomedical Science Institute, Kyung Hee University, Heogi-Dong 1, Dongdaemun-Gu, Seoul, 130-701, Republic of Korea
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Park DW, Jiang S, Tadie JM, Stigler WS, Gao Y, Deshane J, Abraham E, Zmijewski JW. Activation of AMPK enhances neutrophil chemotaxis and bacterial killing. Mol Med 2013; 19:387-98. [PMID: 24091934 DOI: 10.2119/molmed.2013.00065] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 09/20/2013] [Indexed: 01/04/2023] Open
Abstract
An inability of neutrophils to eliminate invading microorganisms is frequently associated with severe infection and may contribute to the high mortality rates associated with sepsis. In the present studies, we examined whether metformin and other 5' adenosine monophosphate-activated protein kinase (AMPK) activators affect neutrophil motility, phagocytosis and bacterial killing. We found that activation of AMPK enhanced neutrophil chemotaxis in vitro and in vivo, and also counteracted the inhibition of chemotaxis induced by exposure of neutrophils to lipopolysaccharide (LPS). In contrast, small interfering RNA (siRNA)-mediated knockdown of AMPKα1 or blockade of AMPK activation through treatment of neutrophils with the AMPK inhibitor compound C diminished neutrophil chemotaxis. In addition to their effects on chemotaxis, treatment of neutrophils with metformin or aminoimidazole carboxamide ribonucleotide (AICAR) improved phagocytosis and bacterial killing, including more efficient eradication of bacteria in a mouse model of peritonitis-induced sepsis. Immunocytochemistry showed that, in contrast to LPS, metformin or AICAR induced robust actin polymerization and distinct formation of neutrophil leading edges. Although LPS diminished AMPK phosphorylation, metformin or AICAR was able to partially decrease the effects of LPS/toll-like receptor 4 (TLR4) engagement on downstream signaling events, particularly LPS-induced IκBα degradation. The IκB kinase (IKK) inhibitor PS-1145 diminished IκBα degradation and also prevented LPS-induced inhibition of chemotaxis. These results suggest that AMPK activation with clinically approved agents, such as metformin, may facilitate bacterial eradication in sepsis and other inflammatory conditions associated with inhibition of neutrophil activation and chemotaxis.
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Affiliation(s)
- Dae Won Park
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America Division of Infectious Diseases, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Shaoning Jiang
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jean-Marc Tadie
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America Service des Maladies Infectieuses et Réanimation Médicale, Centre Hospitalier Universitaire, Rennes, France
| | - William S Stigler
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Yong Gao
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jessy Deshane
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Edward Abraham
- Office of the Dean, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Jaroslaw W Zmijewski
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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D'Alessandro G, Catalano M, Sciaccaluga M, Chece G, Cipriani R, Rosito M, Grimaldi A, Lauro C, Cantore G, Santoro A, Fioretti B, Franciolini F, Wulff H, Limatola C. KCa3.1 channels are involved in the infiltrative behavior of glioblastoma in vivo. Cell Death Dis 2013; 4:e773. [PMID: 23949222 PMCID: PMC3763441 DOI: 10.1038/cddis.2013.279] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/25/2013] [Accepted: 07/02/2013] [Indexed: 01/03/2023]
Abstract
Glioblastoma multiforme (GBM) is a diffuse brain tumor characterized by high infiltration in the brain parenchyma rendering the tumor difficult to eradicate by neurosurgery. Efforts to identify molecular targets involved in the invasive behavior of GBM suggested ion channel inhibition as a promising therapeutic approach. To determine if the Ca(2+)-dependent K(+) channel KCa3.1 could represent a key element for GBM brain infiltration, human GL-15 cells were xenografted into the brain of SCID mice that were then treated with the specific KCa3.1 blocker TRAM-34 (1-((2-chlorophenyl) (diphenyl)methyl)-1H-pyrazole). After 5 weeks of treatment, immunofluorescence analyses of cerebral slices revealed reduced tumor infiltration and astrogliosis surrounding the tumor, compared with untreated mice. Significant reduction of tumor infiltration was also observed in the brain of mice transplanted with KCa3.1-silenced GL-15 cells, indicating a direct effect of TRAM-34 on GBM-expressed KCa3.1 channels. As KCa3.1 channels are also expressed on microglia, we investigated the effects of TRAM-34 on microglia activation in GL-15 transplanted mice and found a reduction of CD68 staining in treated mice. Similar results were observed in vitro where TRAM-34 reduced both phagocytosis and chemotactic activity of primary microglia exposed to GBM-conditioned medium. Taken together, these results indicate that KCa3.1 activity has an important role in GBM invasiveness in vivo and that its inhibition directly affects glioma cell migration and reduces astrocytosis and microglia activation in response to tumor-released factors. KCa3.1 channel inhibition therefore constitutes a potential novel therapeutic approach to reduce GBM spreading into the surrounding tissue.
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Affiliation(s)
- G D'Alessandro
- Institute Pasteur, Cenci Bolognetti Foundation, Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
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36
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Shin YH, Lee SJ, Jung J. Extracellular ATP inhibits Schwann cell dedifferentiation and proliferation in an ex vivo model of Wallerian degeneration. Biochem Biophys Res Commun 2013; 430:852-7. [PMID: 23194661 DOI: 10.1016/j.bbrc.2012.11.057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 11/14/2012] [Indexed: 12/31/2022]
Abstract
After nerve injury, Schwann cells proliferate and revert to a phenotype that supports nerve regeneration. This phenotype-changing process can be viewed as Schwann cell dedifferentiation. Here, we investigated the role of extracellular ATP in Schwann cell dedifferentiation and proliferation during Wallerian degeneration. Using several markers of Schwann cell dedifferentiation and proliferation in sciatic explants, we found that extracellular ATP inhibits Schwann cell dedifferentiation and proliferation during Wallerian degeneration. Furthermore, the blockage of lysosomal exocytosis in ATP-treated sciatic explants is sufficient to induce Schwann cell dedifferentiation. Together, these findings suggest that ATP-induced lysosomal exocytosis may be involved in Schwann cell dedifferentiation.
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Affiliation(s)
- Youn Ho Shin
- Department of Anatomy, College of Medicine, Kyung Hee University, Heogi-Dong 1, Dongdaemun-Gu, Seoul 130-701, Republic of Korea
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37
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Possible ATP release through lysosomal exocytosis from primary sensory neurons. Biochem Biophys Res Commun 2012; 430:488-93. [PMID: 23237805 DOI: 10.1016/j.bbrc.2012.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 12/04/2012] [Indexed: 12/12/2022]
Abstract
The adenosine triphosphate (ATP) plays important roles under physiological and pathological conditions such as traumatic brain injury, neuroinflammation and neuropathic pain. In the present study, we set out to study the role of lysosomal vesicles on ATP release from the dorsal root ganglion neurons. We found that the lysosomal vesicles, which contain the quinacrine-positive fluorescence and express the vesicular nucleotide transporter (VNUT), were localized within the soma and growth cone of the cultured dorsal root ganglion neurons. In addition, the number of the quinacrine staining was decreased by application of lysosomal exocytosis activators, and this decrease was suppressed by the metformin and vacuolin-1, which suppressed lysosomal exocytosis. Thus, these findings suggest that ATP release via the lysosomal exocytosis may be one of the pathways for ATP release in response to stimulation.
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38
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Shin YH, Lee SJ, Jung J. Secretion of ATP from Schwann cells through lysosomal exocytosis during Wallerian degeneration. Biochem Biophys Res Commun 2012; 429:163-7. [PMID: 23142593 DOI: 10.1016/j.bbrc.2012.10.121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 10/29/2012] [Indexed: 12/18/2022]
Abstract
The present study demonstrates that adenosine triphosphate (ATP) is released from Schwann cells through lysosomal exocytosis during Wallerian degeneration and in response to stimulation. In primary Schwann cell cultures, ATP was stored in lysosomal vesicles. ATP could then induce Ca(2+)-dependent lysosomal exocytosis. Among three stimulants of lysosomal exocytosis (glutamate, NH(4)Cl and zymosan), only NH(4)Cl was sufficient to induce ATP release from ex vivo sciatic nerve explants at 3 days in vitro. Lysosomal exocytosis inhibitors (metformin, chlorpromazine and vacuolin-1) reversed the effect of NH(4)Cl-enhanced ATP release, replicating the state of explants treated with NH(4)Cl in the absence of lysosomal exocytosis inhibitors. Furthermore, we observed ATP release through lysosomal exocytosis during Wallerian degeneration in sciatic explant cultures using the recently identified vesicular nucleotide transporter (VNUT). From these experiments, we conclude that the exocytosis of lysosomes in Schwann cells during Wallerian degeneration is Ca(2+)-dependent, and that it induces ATP release from Schwann cells.
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Affiliation(s)
- Youn Ho Shin
- Department of Anatomy, College of Medicine, Kyung Hee University, Heogi-Dong 1, Dongdaemun-Gu, Seoul 130-701, Republic of Korea
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39
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Gomez DI, Twahirwa M, Schlesinger LS, Restrepo BI. Reduced Mycobacterium tuberculosis association with monocytes from diabetes patients that have poor glucose control. Tuberculosis (Edinb) 2012; 93:192-7. [PMID: 23131496 DOI: 10.1016/j.tube.2012.10.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 10/09/2012] [Indexed: 12/16/2022]
Abstract
The re-emerging importance of type 2 diabetes mellitus (DM) to tuberculosis (TB) control is of growing concern, but the basis for this relationship is poorly understood. Given the importance of mononuclear phagocytes for TB control and the reported alterations in monocytes of DM patients, we evaluated whether the initial interaction between both was affected in diabetics. Mycobacterium tuberculosis-naïve individuals with and without DM were group matched by age and gender and the efficiency of M. tuberculosis association (attachment and ingestion) with their monocytes was assessed in the presence of autologous serum. The association of M. tuberculosis with monocytes was significantly lower in diabetics (19.2 ± 6.1) than non-diabetics (27.5 ± 7.9; p = 0.02). Multivariate analysis controlling for host socio demographics, DM characteristics and serum lipids indicated that male gender (p = 0.04) and poorly-controlled DM (high HbA1c and hyperglycemia; p = 0.01) were significantly associated with the lower interaction of M. tuberculosis with monocytes. Serum heat-inactivation reduced the association of M. tuberculosis to similar levels in both study groups (p = 0.69) suggesting alterations in the complement pathway of DM patients. These findings suggest an altered route of entry of the pathogen in DM patients that may influence the downstream activation of signaling pathways in the monocyte and the survival of mycobacteria.
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Affiliation(s)
- Diana I Gomez
- Division of Epidemiology, University of Texas Health Science Center at Houston, School of Public Health at Brownsville, 80 Fort Brown, SPH Bldg, Brownsville, TX 78520, USA.
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40
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Cipriani R, Villa P, Chece G, Lauro C, Paladini A, Micotti E, Perego C, De Simoni MG, Fredholm BB, Eusebi F, Limatola C. CX3CL1 is neuroprotective in permanent focal cerebral ischemia in rodents. J Neurosci 2011; 31:16327-35. [PMID: 22072684 PMCID: PMC6633249 DOI: 10.1523/jneurosci.3611-11.2011] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 08/18/2011] [Accepted: 08/28/2011] [Indexed: 12/13/2022] Open
Abstract
The chemokine CX3CL1 and its receptor CX3CR1 are constitutively expressed in the nervous system. In this study, we used in vivo murine models of permanent middle cerebral artery occlusion (pMCAO) to investigate the protective potential of CX3CL1. We report that exogenous CX3CL1 reduced ischemia-induced cerebral infarct size, neurological deficits, and caspase-3 activation. CX3CL1-induced neuroprotective effects were long lasting, being observed up to 50 d after pMCAO in rats. The neuroprotective action of CX3CL1 in different models of brain injuries is mediated by its inhibitory activity on microglia and, in vitro, requires the activation of adenosine receptor 1 (A₁R). We show that, in the presence of the A₁R antagonist 1,3-dipropyl-8-cyclopentylxanthine and in A₁R⁻/⁻ mice, the neuroprotective effect of CX3CL1 on pMCAO was abolished, indicating the critical importance of the adenosine system in CX3CL1 protection also in vivo. In apparent contrast with the above reported data but in agreement with previous findings, cx3cl1⁻/⁻ and cx3cr1(GFP/GFP) mice, respectively, deficient in CX3CL1 or CX3CR1, had less severe brain injury on pMCAO, and the administration of exogenous CX3CL1 increased brain damage in cx3cl1⁻/⁻ ischemic mice. We also report that CX3CL1 induced a different phagocytic activity in wild type and cx3cl1⁻/⁻ microglia in vitro during cotreatment with the medium conditioned by neurons damaged by oxygen-glucose deprivation. Together, these data suggest that acute administration of CX3CL1 reduces ischemic damage via an adenosine-dependent mechanism and that the absence of constitutive CX3CL1-CX3CR1 signaling changes the outcome of microglia-mediated effects during CX3CL1 administration to ischemic brain.
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MESH Headings
- Adenosine A1 Receptor Antagonists/therapeutic use
- Analysis of Variance
- Animals
- Animals, Genetically Modified
- Animals, Newborn
- Brain Infarction/etiology
- Brain Infarction/prevention & control
- CX3C Chemokine Receptor 1
- Cells, Cultured
- Cerebral Cortex/cytology
- Chemokine CX3CL1/deficiency
- Chemokine CX3CL1/metabolism
- Chemokine CX3CL1/therapeutic use
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Enzyme-Linked Immunosorbent Assay/methods
- Glucose/deficiency
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Humans
- Hypoxia/prevention & control
- Infarction, Middle Cerebral Artery/complications
- Infarction, Middle Cerebral Artery/metabolism
- Infarction, Middle Cerebral Artery/prevention & control
- Magnetic Resonance Imaging
- Male
- Mice
- Mice, Inbred C57BL
- Nervous System Diseases/etiology
- Nervous System Diseases/metabolism
- Nervous System Diseases/therapy
- Neurons/drug effects
- Phagocytosis/drug effects
- Rats
- Receptors, Chemokine/deficiency
- Receptors, Purinergic P1/deficiency
- Xanthines/therapeutic use
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Affiliation(s)
- Raffaela Cipriani
- Institute Pasteur–Fondazione Cenci Bolognetti, Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy
| | - Pia Villa
- Consiglio Nazionale delle Ricerche, Neuroscience Institute, 20129 Milan, Italy
- Mario Negri Institute, 20156 Milan, Italy
| | - Giuseppina Chece
- Institute Pasteur–Fondazione Cenci Bolognetti, Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy
| | - Clotilde Lauro
- Institute Pasteur–Fondazione Cenci Bolognetti, Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy
| | | | | | | | | | - Bertil B. Fredholm
- Department of Physiology, Karolinska Institute, 171 77 Stockholm, Sweden, and
| | - Fabrizio Eusebi
- Institute Pasteur–Fondazione Cenci Bolognetti, Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy
- Instituto di Ricovero e Cura a Carattere Scientifico, NeuroMed, 86077 Pozzilli, Italy
| | - Cristina Limatola
- Institute Pasteur–Fondazione Cenci Bolognetti, Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy
- Instituto di Ricovero e Cura a Carattere Scientifico, NeuroMed, 86077 Pozzilli, Italy
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41
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Chen YC, Lu PH, Hsu JL, Yu CC, Guh JH. ICAM-1 and AMPK regulate cell detachment and apoptosis by N-methyl-N'-nitro-N-nitrosoguanidine, a widely spread environmental chemical, in human hormone-refractory prostate cancers. Toxicol Appl Pharmacol 2011; 257:412-9. [PMID: 22001597 DOI: 10.1016/j.taap.2011.09.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 09/12/2011] [Accepted: 09/29/2011] [Indexed: 01/29/2023]
Abstract
Poly(ADP-ribose) polymerase-1 (PARP-1), a sensor of DNA damage, plays a crucial role in the regulation of DNA repair. PARP-1 hyperactivation causes DNA damage and cell death. The underlying mechanism is complicated and is through diverse pathways. The understanding of responsible signaling pathways may offer implications for effective therapies. After concentration-response determination of N-Methyl-N'-Nitro-N-Nitrosoguanidine (MNNG, a PARP-1 activating agent and an environmental mutagen) in human hormone-refractory prostate cancers, the data showed that concentrations below 5μM did not change cell survival but cause a time-dependent up-regulation of intracellular adhesion molecule-1 (ICAM-1) in mRNA, total protein and cell surface levels. Detection of phosphorylation and degradation of IκB-α and nuclear translocation of NF-κB showed that MNNG induced the activation of NF-κB that was responsible for the ICAM-1 up-regulation since PDTC (a NF-κB inhibitor) significantly abolished this effect. However, higher concentrations (e.g., 10μM) of MNNG induced a 61% detachment of the cells which were apoptosis associated with the activation of AMP-activated protein kinase (AMPK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Further identification showed that both AMPK and JNK other than p38 MAPK functionally contributed to cell death. The remaining 39% attached cells were survival associated with high ICAM-1 expression. In conclusion, the data suggest that NF-κB-dependent up-regulation of ICAM-1 plays a key role on cell attachment and survival; whereas, activation of AMPK and JNK participates in cytotoxic signaling pathways in detached cells caused by PARP-1 activation.
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Affiliation(s)
- Yi-Cheng Chen
- School of Pharmacy, College of Medicine, National Taiwan University, No. 1, Sect. 1, Jen-Ai Rd, Taipei 100, Taiwan
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Abstract
Abstract Geroprotectors are drugs that decrease the rate of aging and therefore extend life span. Metformin has been described as a geroprotector, and several studies have shown that metformin can slow down the rate of aging. The mechanisms behind the geroprotective effect of metformin are less established. The goal of this review is to investigate the evidence for the geroprotective effect of metformin and to describe the possible mechanisms behind it.
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43
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Bae HB, Zmijewski JW, Deshane JS, Tadie JM, Chaplin DD, Takashima S, Abraham E. AMP-activated protein kinase enhances the phagocytic ability of macrophages and neutrophils. FASEB J 2011; 25:4358-68. [PMID: 21885655 DOI: 10.1096/fj.11-190587] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Although AMPK plays well-established roles in the modulation of energy balance, recent studies have shown that AMPK activation has potent anti-inflammatory effects. In the present experiments, we examined the role of AMPK in phagocytosis. We found that ingestion of Escherichia coli or apoptotic cells by macrophages increased AMPK activity. AMPK activation increased the ability of neutrophils or macrophages to ingest bacteria (by 46 ± 7.8 or 85 ± 26%, respectively, compared to control, P<0.05) and the ability of macrophages to ingest apoptotic cells (by 21 ± 1.4%, P<0.05 compared to control). AMPK activation resulted in cytoskeletal reorganization, including enhanced formation of actin and microtubule networks. Activation of PAK1/2 and WAVE2, which are downstream effectors of Rac1, accompanied AMPK activation. AMPK activation also induced phosphorylation of CLIP-170, a protein that participates in microtubule synthesis. The increase in phagocytosis was reversible by the specific AMPK inhibitor compound C, siRNA to AMPKα1, Rac1 inhibitors, or agents that disrupt actin or microtubule networks. In vivo, AMPK activation resulted in enhanced phagocytosis of bacteria in the lungs by 75 ± 5% vs. control (P<0.05). These results demonstrate a novel function for AMPK in enhancing the phagocytic activity of neutrophils and macrophages.
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Affiliation(s)
- Hong-Beom Bae
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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44
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Salminen A, Kaarniranta K, Haapasalo A, Soininen H, Hiltunen M. AMP-activated protein kinase: a potential player in Alzheimer's disease. J Neurochem 2011; 118:460-74. [PMID: 21623793 DOI: 10.1111/j.1471-4159.2011.07331.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
AMP-activated protein kinase (AMPK) stimulates energy production via glucose and lipid metabolism, whereas it inhibits energy consuming functions, such as protein and cholesterol synthesis. Increased cytoplasmic AMP and Ca(2+) levels are the major activators of neuronal AMPK signaling. Interestingly, Alzheimer's disease (AD) is associated with several abnormalities in neuronal energy metabolism, for example, decline in glucose uptake, mitochondrial dysfunctions and defects in cholesterol metabolism, and in addition, with problems in maintaining Ca(2+) homeostasis. Epidemiological studies have also revealed that many metabolic and cardiovascular diseases are risk factors for cognitive impairment and sporadic AD. Emerging studies indicate that AMPK signaling can regulate tau protein phosphorylation and amyloidogenesis, the major hallmarks of AD. AMPK is also a potent activator of autophagic degradation which seems to be suppressed in AD. All these observations imply that AMPK is involved in the pathogenesis of AD. However, the responses of AMPK activation are dependent on stimulation and the extent of activating stress. Evidently, AMPK signaling can repress and delay the appearance of AD pathology but later on, with increasing neuronal stress, it can trigger detrimental effects that augment AD pathogenesis. We will outline the potential role of AMPK function in respect to various aspects affecting AD pathogenesis.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
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Łabuzek K, Suchy D, Gabryel B, Bielecka A, Liber S, Okopień B. Quantification of metformin by the HPLC method in brain regions, cerebrospinal fluid and plasma of rats treated with lipopolysaccharide. Pharmacol Rep 2011; 62:956-65. [PMID: 21098880 DOI: 10.1016/s1734-1140(10)70357-1] [Citation(s) in RCA: 274] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 04/13/2010] [Indexed: 10/25/2022]
Abstract
Recently, it has been reported that metformin may attenuate inflammation and directly act on the central nervous system. Using the HPLC method, in Wistar rats, we assessed the changes in metformin concentrations in various brain regions (pituitary gland, olfactory bulb, hypothalamus, cerebellum, hippocampus, striatum, frontal cortex), cerebrospinal fluid and plasma after single and chronic oral administration, in the model of systemic inflammation induced by lipopolysaccharide (ip). Regarding the influence of systemic inflammation on metformin distribution, the pituitary gland demonstrated the highest its level after single and chronic administration (28.8 ± 3.5 nmol/g and 24.9 ± 3.2 nmol/g, respectively). We concluded that orally-dosed metformin rapidly crosses the blood-brain barrier and differently accumulates in structures of the central nervous system.
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Affiliation(s)
- Krzysztof Łabuzek
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Medyków 18, PL40-752 Katowice, Poland.
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