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Yin K, Chen T, Gu X, Su W, Jiang Z, Lu S, Cao B, Chi L, Gao X, Chen Y. Systematic druggable genome-wide Mendelian randomization identifies therapeutic targets for sarcopenia. J Cachexia Sarcopenia Muscle 2024; 15:1324-1334. [PMID: 38644354 PMCID: PMC11294052 DOI: 10.1002/jcsm.13479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 02/27/2024] [Accepted: 03/07/2024] [Indexed: 04/23/2024] Open
Abstract
BACKGROUND There are no effective pharmacological treatments for sarcopenia. We aim to identify potential therapeutic targets for sarcopenia by integrating various publicly available datasets. METHODS We integrated druggable genome data, cis-eQTL/cis-pQTL from human blood and skeletal muscle tissue, and GWAS summary data of sarcopenia-related traits to analyse the potential causal relationships between drug target genes and sarcopenia using the Mendelian Randomization (MR) method. Sensitivity analyses and Bayesian colocalization were employed to validate the causal relationships. We also assessed the side effects or additional indications of the identified drug targets using a phenome-wide MR (Phe-MR) approach and investigated actionable drugs for target genes using available databases. RESULTS MR analysis identified 17 druggable genes with potential causation to sarcopenia in human blood or skeletal muscle tissue. Six of them (HP, HLA-DRA, MAP 3K3, MFGE8, COL15A1, and AURKA) were further confirmed by Bayesian colocalization (PPH4 > 90%). The up-regulation of HP [higher ALM (beta: 0.012, 95% CI: 0.007-0.018, P = 1.2*10-5) and higher grip strength (OR: 0.96, 95% CI: 0.94-0.98, P = 4.2*10-5)], MAP 3K3 [higher ALM (beta: 0.24, 95% CI: 0.21-0.26, P = 1.8*10-94), higher grip strength (OR: 0.82, 95% CI: 0.75-0.90, P = 2.1*10-5), and faster walking pace (beta: 0.03, 95% CI: 0.02-0.05, P = 8.5*10-6)], and MFGE8 [higher ALM (muscle eQTL, beta: 0.09, 95% CI: 0.06-0.11, P = 6.1*10-13; blood pQTL, beta: 0.05, 95% CI: 0.03-0.07, P = 3.8*10-09)], as well as the down-regulation of HLA-DRA [lower ALM (beta: -0.09, 95% CI: -0.11 to -0.08, P = 5.4*10-36) and lower grip strength (OR: 1.13, 95% CI: 1.07-1.20, P = 1.8*10-5)] and COL15A1 [higher ALM (muscle eQTL, beta: -0.07, 95% CI: -0.10 to -0.04, P = 3.4*10-07; blood pQTL, beta: -0.05, 95% CI: -0.06 to -0.03, P = 1.6*10-07)], decreased the risk of sarcopenia. AURKA in blood (beta: -0.16, 95% CI: -0.22 to -0.09, P = 2.1*10-06) and skeletal muscle (beta: 0.03, 95% CI: 0.02 to 0.05, P = 5.3*10-05) tissues showed an inverse relationship with sarcopenia risk. The Phe-MR indicated that the six potential therapeutic targets for sarcopenia had no significant adverse effects. Drug repurposing analysis supported zinc supplementation and collagenase clostridium histolyticum might be potential therapeutics for sarcopenia by activating HP and inhibiting COL15A1, respectively. CONCLUSIONS Our research indicated MAP 3K3, MFGE8, COL15A1, HP, and HLA-DRA may serve as promising targets for sarcopenia, while the effectiveness of zinc supplementation and collagenase clostridium histolyticum for sarcopenia requires further validation.
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Affiliation(s)
- Kang‐Fu Yin
- Department of Neurology, West China HospitalSichuan UniversityChengduChina
- Institute of Brain Science and Brain‐Inspired Technology, West China HospitalSichuan UniversityChengduChina
| | - Ting Chen
- Department of Neurology, West China HospitalSichuan UniversityChengduChina
- Institute of Brain Science and Brain‐Inspired Technology, West China HospitalSichuan UniversityChengduChina
| | - Xiao‐Jing Gu
- Mental Health Center, West China HospitalSichuan UniversityChengduChina
| | - Wei‐Ming Su
- Department of Neurology, West China HospitalSichuan UniversityChengduChina
- Institute of Brain Science and Brain‐Inspired Technology, West China HospitalSichuan UniversityChengduChina
| | - Zheng Jiang
- Department of Neurology, West China HospitalSichuan UniversityChengduChina
- Institute of Brain Science and Brain‐Inspired Technology, West China HospitalSichuan UniversityChengduChina
| | - Si‐Jia Lu
- Department of RespiratoryThe Fourth People's Hospital of Chengdu, Mental Health Center of ChengduChengduChina
| | - Bei Cao
- Department of Neurology, West China HospitalSichuan UniversityChengduChina
- Institute of Brain Science and Brain‐Inspired Technology, West China HospitalSichuan UniversityChengduChina
| | - Li‐Yi Chi
- Department of NeurologyFirst Affiliated Hospital of Air Force Military Medical UniversityXi'anChina
| | - Xia Gao
- Department of GeriatricsDazhou Central HospitalDazhouChina
| | - Yong‐Ping Chen
- Department of Neurology, West China HospitalSichuan UniversityChengduChina
- Institute of Brain Science and Brain‐Inspired Technology, West China HospitalSichuan UniversityChengduChina
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Abar L, Zuber V, Otto GW, Tzoulaki I, Dehghan A. Unravelling genetic architecture of circulatory amino acid levels, and their effect on risk of complex disorders. NAR Genom Bioinform 2024; 6:lqae046. [PMID: 38711861 PMCID: PMC11071119 DOI: 10.1093/nargab/lqae046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/27/2024] [Accepted: 04/23/2024] [Indexed: 05/08/2024] Open
Abstract
Variations in serum amino acid levels are linked to a multitude of complex disorders. We report the largest genome-wide association study (GWAS) on nine serum amino acids in the UK Biobank participants (117 944, European descent). We identified 34 genomic loci for circulatory levels of alanine, 48 loci for glutamine, 44 loci for glycine, 16 loci for histidine, 11 loci for isoleucine, 19 loci for leucine, 9 loci for phenylalanine, 32 loci for tyrosine and 20 loci for valine. Our gene-based analysis mapped 46-293 genes associated with serum amino acids, including MIP, GLS2, SLC gene family, GCKR, LMO1, CPS1 and COBLL1.The gene-property analysis across 30 tissues highlighted enriched expression of the identified genes in liver tissues for all studied amino acids, except for isoleucine and valine, in muscle tissues for serum alanine and glycine, in adrenal gland tissues for serum isoleucine and leucine, and in pancreatic tissues for serum phenylalanine. Mendelian randomization (MR) phenome-wide association study analysis and subsequent two-sample MR analysis provided evidence that every standard deviation increase in valine is associated with 35% higher risk of type 2 diabetes and elevated levels of serum alanine and branched-chain amino acids with higher levels of total cholesterol, triglyceride and low-density lipoprotein, and lower levels of high-density lipoprotein. In contrast to reports by observational studies, MR analysis did not support a causal association between studied amino acids and coronary artery disease, Alzheimer's disease, breast cancer or prostate cancer. In conclusion, we explored the genetic architecture of serum amino acids and provided evidence supporting a causal role of amino acids in cardiometabolic health.
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Affiliation(s)
- Leila Abar
- Department of Epidemiology & Biostatistics, School of Public Health, Faculty of Medicine, Imperial College London, St Mary’s Campus, Norfolk Place, London W2 1PG, UK
| | - Verena Zuber
- Department of Epidemiology & Biostatistics, School of Public Health, Faculty of Medicine, Imperial College London, St Mary’s Campus, Norfolk Place, London W2 1PG, UK
| | - Georg W Otto
- Department of Epidemiology & Biostatistics, School of Public Health, Faculty of Medicine, Imperial College London, St Mary’s Campus, Norfolk Place, London W2 1PG, UK
| | - Ioanna Tzoulaki
- Department of Epidemiology & Biostatistics, School of Public Health, Faculty of Medicine, Imperial College London, St Mary’s Campus, Norfolk Place, London W2 1PG, UK
- Centre for Systems Biology, Biomedical Research Foundation Academy of Athens, 115 27 Athens, Greece
- BHF Centre of Excellence, School of Public Health, Imperial College London, London W2 1PG, UK
- UK Dementia Research Institute, Imperial College London, London W12 0BZ, UK
| | - Abbas Dehghan
- Department of Epidemiology & Biostatistics, School of Public Health, Faculty of Medicine, Imperial College London, St Mary’s Campus, Norfolk Place, London W2 1PG, UK
- BHF Centre of Excellence, School of Public Health, Imperial College London, London W2 1PG, UK
- UK Dementia Research Institute, Imperial College London, London W12 0BZ, UK
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Yin KF, Gu XJ, Su WM, Chen T, Long J, Gong L, Ying ZY, Dou M, Jiang Z, Duan QQ, Cao B, Gao X, Chi LY, Chen YP. Causal association and mediating effect of blood biochemical metabolic traits and brain image-derived endophenotypes on Alzheimer's disease. Heliyon 2024; 10:e27422. [PMID: 38644883 PMCID: PMC11033073 DOI: 10.1016/j.heliyon.2024.e27422] [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] [Received: 07/07/2023] [Revised: 01/17/2024] [Accepted: 02/28/2024] [Indexed: 04/23/2024] Open
Abstract
Background Recent genetic evidence supports that circulating biochemical and metabolic traits (BMTs) play a causal role in Alzheimer's disease (AD), which might be mediated by changes in brain structure. Here, we leveraged publicly available genome-wide association study data to investigate the intrinsic causal relationship between blood BMTs, brain image-derived phenotypes (IDPs) and AD. Methods Utilizing the genetic variants associated with 760 blood BMTs and 172 brain IDPs as the exposure and the latest AD summary statistics as the outcome, we analyzed the causal relationship between blood BMTs and brain IDPs and AD by using a two-sample Mendelian randomization (MR) method. Additionally, we used two-step/mediation MR to study the mediating effect of brain IDPs between blood BMTs and AD. Results Twenty-five traits for genetic evidence supporting a causal association with AD were identified, including 12 blood BMTs and 13 brain IDPs. For BMTs, glutamine consistently reduced the risk of AD in 3 datasets. For IDPs, specific alterations of cortical thickness (atrophy in frontal pole and insular lobe, and incrassation in superior parietal lobe) and subcortical volume (atrophy in hippocampus and its subgroups, left accumbens and left choroid plexus, and expansion in cerebral white matter) are vulnerable to AD. In the two-step/mediation MR analysis, superior parietal lobe, right hippocampal fissure and left accumbens were identified to play a potential mediating role among three blood BMTs and AD. Conclusions The results obtained in our study suggest that 12 circulating BMTs and 13 brain IDPs play a causal role in AD. Importantly, a subset of BMTs exhibit shared genetic architecture and potentially causal relationships with brain structure, which may contribute to the alteration of brain IDPs in AD.
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Affiliation(s)
- Kang-Fu Yin
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xiao-Jing Gu
- Mental Health Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Wei-Ming Su
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Ting Chen
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jiang Long
- Mental Health Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Li Gong
- Rare Diseases Center, Outpatient Department, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Zhi-Ye Ying
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Meng Dou
- Chengdu institute of computer application, Chinese Academy of Sciences, Chengdu, 610041, Sichuan, China
| | - Zheng Jiang
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Qing-Qing Duan
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Bei Cao
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xia Gao
- Department of Geriatrics, Dazhou central hospital, Dazhou, 635000, Sichuan, China
| | - Li-Yi Chi
- Department of Neurology, First Affiliated Hospital of Air Force Military Medical University, Xi'an, 710072, Shanxi, China
| | - Yong-Ping Chen
- Department of Neurology, Institute of Brain Science and Brain-inspired Technology, Centre for Rare Diseases, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
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Braunstein PW, Horovitz DJ, Hampton AM, Hollis F, Newman LA, Enos RT, McQuail JA. Daily fluctuations in blood glucose with normal aging are inversely related to hippocampal synaptic mitochondrial proteins. AGING BRAIN 2024; 5:100116. [PMID: 38596458 PMCID: PMC11002859 DOI: 10.1016/j.nbas.2024.100116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/11/2024] Open
Abstract
Defective brain glucose utilization is a hallmark of Alzheimer's disease (AD) while Type II diabetes and elevated blood glucose escalate the risk for AD in later life. Isolating contributions of normal aging from coincident metabolic or brain diseases could lead to refined approaches to manage specific health risks and optimize treatments targeted to susceptible older individuals. We evaluated metabolic, neuroendocrine, and neurobiological differences between young adult (6 months) and aged (24 months) male rats. Compared to young adults, blood glucose was significantly greater in aged rats at the start of the dark phase of the day but not during the light phase. When challenged with physical restraint, a potent stressor, aged rats effected no change in blood glucose whereas blood glucose increased in young adults. Tissues were evaluated for markers of oxidative phosphorylation (OXPHOS), neuronal glucose transport, and synapses. Outright differences in protein levels between age groups were not evident, but circadian blood glucose was inversely related to OXPHOS proteins in hippocampal synaptosomes, independent of age. The neuronal glucose transporter, GLUT3, was positively associated with circadian blood glucose in young adults whereas aged rats tended to show the opposite trend. Our data demonstrate aging increases daily fluctuations in blood glucose and, at the level of individual differences, negatively associates with proteins related to synaptic OXPHOS. Our findings imply that glucose dyshomeostasis may exacerbate metabolic aspects of synaptic dysfunction that contribute to risk for age-related brain disorders.
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Affiliation(s)
- Paul W. Braunstein
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - David J. Horovitz
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | | | - Fiona Hollis
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Lori A. Newman
- Department of Psychological Science, Vassar College, Poughkeepsie, NY, USA
| | - Reilly T. Enos
- Department of Pathology, Microbiology, and Immunology, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Joseph A. McQuail
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
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Chen Y, Li Y, Fan Y, Chen S, Chen L, Chen Y, Chen Y. Gut microbiota-driven metabolic alterations reveal gut-brain communication in Alzheimer's disease model mice. Gut Microbes 2024; 16:2302310. [PMID: 38261437 PMCID: PMC10807476 DOI: 10.1080/19490976.2024.2302310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 01/03/2024] [Indexed: 01/25/2024] Open
Abstract
The gut microbiota (GM) and its metabolites affect the host nervous system and are involved in the pathogeneses of various neurological diseases. However, the specific GM alterations under pathogenetic pressure and their contributions to the "microbiota - metabolite - brain axis" in Alzheimer's disease (AD) remain unclear. Here, we investigated the GM and the fecal, serum, cortical metabolomes in APP/PS1 and wild-type (WT) mice, revealing distinct hub bacteria in AD mice within scale-free GM networks shared by both groups. Moreover, we identified diverse peripheral - central metabolic landscapes between AD and WT mice that featured bile acids (e.g. deoxycholic and isodeoxycholic acid) and unsaturated fatty acids (e.g. 11Z-eicosenoic and palmitoleic acid). Machine-learning models revealed the relationships between the differential/hub bacteria and these metabolic signatures from the periphery to the brain. Notably, AD-enriched Dubosiella affected AD occurrence via cortical palmitoleic acid and vice versa. Considering the transgenic background of the AD mice, we propose that Dubosiella enrichment impedes AD progression via the synthesis of palmitoleic acid, which has protective properties against inflammation and metabolic disorders. We identified another association involving fecal deoxycholic acid-mediated interactions between the AD hub bacteria Erysipelatoclostridium and AD occurrence, which was corroborated by the correlation between deoxycholate levels and cognitive scores in humans. Overall, this study elucidated the GM network alterations, contributions of the GM to peripheral - central metabolic landscapes, and mediatory roles of metabolites between the GM and AD occurrence, thus revealing the critical roles of bacteria in AD pathogenesis and gut - brain communications under pathogenetic pressure.
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Affiliation(s)
- Yijing Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen–Hong Kong Institute of Brain Science–Shenzhen Fundamental Research Institutions, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, China
| | - Yinhu Li
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen–Hong Kong Institute of Brain Science–Shenzhen Fundamental Research Institutions, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, China
| | - Yingying Fan
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen–Hong Kong Institute of Brain Science–Shenzhen Fundamental Research Institutions, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, China
| | - Shuai Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen–Hong Kong Institute of Brain Science–Shenzhen Fundamental Research Institutions, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, China
| | - Li Chen
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yuewen Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen–Hong Kong Institute of Brain Science–Shenzhen Fundamental Research Institutions, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, China
| | - Yu Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen–Hong Kong Institute of Brain Science–Shenzhen Fundamental Research Institutions, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, China
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McNair LM, Andersen JV, Waagepetersen HS. Stable isotope tracing reveals disturbed cellular energy and glutamate metabolism in hippocampal slices of aged male mice. Neurochem Int 2023; 171:105626. [PMID: 37838084 DOI: 10.1016/j.neuint.2023.105626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/08/2023] [Accepted: 10/05/2023] [Indexed: 10/16/2023]
Abstract
Neurons and astrocytes work in close metabolic collaboration, linking neurotransmission to brain energy and neurotransmitter metabolism. Dysregulated energy metabolism is a hallmark of the aging brain and may underlie the progressive age-dependent cognitive decline. However, astrocyte and neurotransmitter metabolism remains understudied in aging brain research. In particular, how aging affects metabolism of glutamate, being the primary excitatory neurotransmitter, is still poorly understood. Here we investigated critical aspects of cellular energy metabolism in the aging male mouse hippocampus using stable isotope tracing in vitro. Metabolism of [U-13C]glucose demonstrated an elevated glycolytic capacity of aged hippocampal slices, whereas oxidative [U-13C]glucose metabolism in the TCA cycle was significantly reduced with aging. In addition, metabolism of [1,2-13C]acetate, reflecting astrocyte energy metabolism, was likewise reduced in the hippocampal slices of old mice. In contrast, uptake and subsequent metabolism of [U-13C]glutamate was elevated, suggesting increased capacity for cellular glutamate handling with aging. Finally, metabolism of [15N]glutamate was maintained in the aged slices, demonstrating sustained glutamate nitrogen metabolism. Collectively, this study reveals fundamental alterations in cellular energy and neurotransmitter metabolism in the aging brain, which may contribute to age-related hippocampal deficits.
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Affiliation(s)
- Laura Mikél McNair
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Jens Velde Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Helle Sønderby Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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Guo Y, Zhao T, Chu X, Cheng Z. Development of a diagnostic and risk prediction model for Alzheimer's disease through integration of single-cell and bulk transcriptomic analysis of glutamine metabolism. Front Aging Neurosci 2023; 15:1275793. [PMID: 38020758 PMCID: PMC10667556 DOI: 10.3389/fnagi.2023.1275793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023] Open
Abstract
Background In this study, we present a novel system for quantifying glutamine metabolism (GM) to enhance the effectiveness of Alzheimer's disease (AD) diagnosis and risk prediction. Methods Single-cell RNA sequencing (scRNA-seq) analysis was utilized to comprehensively assess the expression patterns of GM. The WGCNA algorithm was applied to investigate the most significant genes related to GM. Subsequently, three machine learning algorithms (Boruta, LASSO, and SVM-RFE) were employed to identify GM-associated characteristic genes and develop a risk model. Patients were divided into high- and low-risk groups based on this model. Moreover, we explored biological properties, distinct signaling pathways, and immunological characteristics of AD patients at different risk levels. Finally, in vitro and in vivo models of AD were constructed to validate the characteristics of the feature genes. Results Both scRNA-seq and bulk transcriptomic analyses revealed increased GM activity in AD patients, specifically in certain cell subsets (pDC, Tem/Effector helper T cells (LTB), and plasma cells). Cells with higher GM scores demonstrated more significant numbers and strengths of interactions with other cell types. The WGCNA algorithm identified 360 genes related to GM, and a risk score was constructed based on nine characteristic genes (ATP13A4, PIK3C2A, CD164, PHF1, CES2, PDGFB, LCOR, TMEM30A, and PLXNA1) identified through multiple machine learning algorithms displayed reliable diagnostic efficacy for AD onset. Nomograms, calibration curves, and decision curve analysis (DCA) based on these characteristic genes provided significant clinical benefits for AD patients. High-risk AD patients exhibited higher levels of immune-related functions and pathways, increased immune cell infiltration, and elevated expressions of immune modulators. RT-qPCR analysis revealed that the majority of the nine characteristic genes were differentially expressed in AD-induced rat neurons. Knocking down PHF1 could protect against neurite loss and alleviate cell injury in AD neurons. In vivo, down-regulation of PHF1 in AD models decreases GM metabolism levels and modulates the immunoinflammatory response in the brain. Conclusion This comprehensive identification of gene expression patterns contributes to a deeper understanding of the underlying pathological mechanisms driving AD pathogenesis. Furthermore, the risk model based on the nine-gene signature offers a promising theoretical foundation for developing individualized treatments for AD patients.
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Affiliation(s)
- Yan Guo
- Department of Clinical Laboratory, Key Clinical Laboratory of Henan Province, Zhengzhou, Henan, China
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Tingru Zhao
- Department of Clinical Laboratory, Key Clinical Laboratory of Henan Province, Zhengzhou, Henan, China
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Xi Chu
- Department of Clinical Laboratory, Key Clinical Laboratory of Henan Province, Zhengzhou, Henan, China
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Zhenyun Cheng
- Department of Clinical Laboratory, Key Clinical Laboratory of Henan Province, Zhengzhou, Henan, China
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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Jiwaji Z, Hardingham GE. The consequences of neurodegenerative disease on neuron-astrocyte metabolic and redox interactions. Neurobiol Dis 2023; 185:106255. [PMID: 37558170 DOI: 10.1016/j.nbd.2023.106255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/24/2023] [Accepted: 08/05/2023] [Indexed: 08/11/2023] Open
Abstract
Brain metabolic pathways relating to bioenergetic and redox homeostasis are closely linked, and deficits in these pathways are thought to occur in many neurodegenerative diseases. Astrocytes play important roles in both processes, and growing evidence suggests that neuron-astrocyte intercellular signalling ensures brain bioenergetic and redox homeostasis in health. Moreover, alterations to this crosstalk have been observed in the context of neurodegenerative pathology. In this review, we summarise the current understanding of how neuron-astrocyte interactions influence brain metabolism and antioxidant functions in health as well as during neurodegeneration. It is apparent that deleterious and adaptive protective responses alter brain metabolism in disease, and that knowledge of both may illuminate targets for future therapeutic interventions.
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Affiliation(s)
- Zoeb Jiwaji
- United Kingdom Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh, EH16 4SB, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.
| | - Giles E Hardingham
- United Kingdom Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh, EH16 4SB, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
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Latina V, Atlante A, Malerba F, La Regina F, Balzamino BO, Micera A, Pignataro A, Stigliano E, Cavallaro S, Calissano P, Amadoro G. The Cleavage-Specific Tau 12A12mAb Exerts an Anti-Amyloidogenic Action by Modulating the Endocytic and Bioenergetic Pathways in Alzheimer's Disease Mouse Model. Int J Mol Sci 2023; 24:ijms24119683. [PMID: 37298634 DOI: 10.3390/ijms24119683] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/27/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Beyond deficits in hippocampal-dependent episodic memory, Alzheimer's Disease (AD) features sensory impairment in visual cognition consistent with extensive neuropathology in the retina. 12A12 is a monoclonal cleavage specific antibody (mAb) that in vivo selectively neutralizes the AD-relevant, harmful N-terminal 20-22 kDa tau fragment(s) (i.e., NH2htau) without affecting the full-length normal protein. When systemically injected into the Tg2576 mouse model overexpressing a mutant form of Amyloid Precursor Protein (APP), APPK670/671L linked to early onset familial AD, this conformation-specific tau mAb successfully reduces the NH2htau accumulating both in their brain and retina and, thus, markedly alleviates the phenotype-associated signs. By means of a combined biochemical and metabolic experimental approach, we report that 12A12mAb downregulates the steady state expression levels of APP and Beta-Secretase 1 (BACE-1) and, thus, limits the Amyloid beta (Aβ) production both in the hippocampus and retina from this AD animal model. The local, antibody-mediated anti-amyloidogenic action is paralleled in vivo by coordinated modulation of the endocytic (BIN1, RIN3) and bioenergetic (glycolysis and L-Lactate) pathways. These findings indicate for the first time that similar molecular and metabolic retino-cerebral pathways are modulated in a coordinated fashion in response to 12A12mAb treatment to tackle the neurosensorial Aβ accumulation in AD neurodegeneration.
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Affiliation(s)
- Valentina Latina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Anna Atlante
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Francesca Malerba
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Federico La Regina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Bijorn Omar Balzamino
- Research Laboratories in Ophthalmology, IRCCS-Fondazione Bietti, Via Santo Stefano Rotondo 6, 00184 Rome, Italy
| | - Alessandra Micera
- Research Laboratories in Ophthalmology, IRCCS-Fondazione Bietti, Via Santo Stefano Rotondo 6, 00184 Rome, Italy
| | - Annabella Pignataro
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy
| | - Egidio Stigliano
- Area of Pathology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Istituto di Anatomia Patologica, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Sebastiano Cavallaro
- Institute for Biomedical Research and Innovation (IRIB), National Research Council (CNR), Via P. Gaifami 18, 95126 Catania, Italy
| | - Pietro Calissano
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Giuseppina Amadoro
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy
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10
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Westi EW, Andersen JV, Aldana BI. Using stable isotope tracing to unravel the metabolic components of neurodegeneration: Focus on neuron-glia metabolic interactions. Neurobiol Dis 2023; 182:106145. [PMID: 37150307 DOI: 10.1016/j.nbd.2023.106145] [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: 02/23/2023] [Revised: 04/17/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023] Open
Abstract
Disrupted brain metabolism is a critical component of several neurodegenerative diseases. Energy metabolism of both neurons and astrocytes is closely connected to neurotransmitter recycling via the glutamate/GABA-glutamine cycle. Neurons and astrocytes hereby work in close metabolic collaboration which is essential to sustain neurotransmission. Elucidating the mechanistic involvement of altered brain metabolism in disease progression has been aided by the advance of techniques to monitor cellular metabolism, in particular by mapping metabolism of substrates containing stable isotopes, a technique known as isotope tracing. Here we review key aspects of isotope tracing including advantages, drawbacks and applications to different cerebral preparations. In addition, we narrate how isotope tracing has facilitated the discovery of central metabolic features in neurodegeneration with a focus on the metabolic cooperation between neurons and astrocytes.
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Affiliation(s)
- Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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11
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Wu Z, Liu P, Huang B, Deng S, Song Z, Huang X, Yang J, Cheng S. A novel Alzheimer's disease prognostic signature: identification and analysis of glutamine metabolism genes in immunogenicity and immunotherapy efficacy. Sci Rep 2023; 13:6895. [PMID: 37106067 PMCID: PMC10140060 DOI: 10.1038/s41598-023-33277-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Alzheimer's disease (AD) is characterized as a distinct onset and progression of cognitive and functional decline associated with age, as well as a specific neuropathology. It has been discovered that glutamine (Gln) metabolism plays a crucial role in cancer. However, a full investigation of its role in Alzheimer's disease is still missing. This study intended to find and confirm potential Gln-related genes associated with AD using bioinformatics analysis. The discovery of GlnMgs was made possible by the intersection of the WGCNA test and 26 Gln-metabolism genes (GlnMgs). GlnMgs' putative biological functions and pathways were identified using GSVA. The LASSO method was then used to identify the hub genes as well as the diagnostic efficiency of the four GlnMgs in identifying AD. The association between hub GlnMgs and clinical characteristics was also studied. Finally, the GSE63060 was utilized to confirm the levels of expression of the four GlnMgs. Four GlnMgs were discovered (ATP5H, NDUFAB1, PFN2, and SPHKAP). For biological function analysis, cell fate specification, atrioventricular canal development, and neuron fate specification were emphasized. The diagnostic ability of the four GlnMgs in differentiating AD exhibited a good value. This study discovered four GlnMgs that are linked to AD. They shed light on potential new biomarkers for AD and tracking its progression.
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Affiliation(s)
- Zixuan Wu
- Hunan University of Chinese Medicine, Changsha, 410128, China
| | - Ping Liu
- Hunan University of Chinese Medicine, Changsha, 410128, China
| | - Baisheng Huang
- Guangzhou University of Chinese Medicine, Guangzhou, 510120, China
| | - Sisi Deng
- Hunan University of Chinese Medicine, Changsha, 410128, China
| | - Zhenyan Song
- Hunan University of Chinese Medicine, Changsha, 410128, China
| | - Xindi Huang
- Hunan University of Chinese Medicine, Changsha, 410128, China
| | - Jing Yang
- Hunan University of Chinese Medicine, Changsha, 410128, China.
| | - Shaowu Cheng
- Hunan University of Chinese Medicine, Changsha, 410128, China.
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12
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Ghosh D, Singh G, Mishra P, Singh A, Kumar A, Sinha N. Alteration in mitochondrial dynamics promotes the proinflammatory response of microglia and is involved in cerebellar dysfunction of young and aged mice following LPS exposure. Neurosci Lett 2023; 807:137262. [PMID: 37116576 DOI: 10.1016/j.neulet.2023.137262] [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: 03/07/2023] [Revised: 04/01/2023] [Accepted: 04/17/2023] [Indexed: 04/30/2023]
Abstract
Cerebellar dysfunction is implicated in impaired motor coordination and balance, thus disturbing the dynamics of sensorimotor integration. Neuroinflammation and aging could be prominent contributors to cerebellar aberration. Additionally, changes in mitochondrial dynamics may precede microglia activation in several chronic neurodegenerative diseases; however, the underlying mechanism remains largely unknown.Here using LPS (1 mg/kg i.p. for four consecutive days) stimulation in both young (3 months old) and aged (12 months old) mice, followed by molecular analysis on the 21st day, we have explored the correlation between aging and mitochondrial dynamic alteration in the backdrop of chronic neuroinflammation. Following LPS stimulation, we observed microglia activation and subsequent elevation in proinflammatory cytokines (M1; TNF-α, IFN-γ) with NLRP3 activationand a concomitant reduction in the expression of anti-inflammatory markers (M2; YM1, TGF-β1) in the cerebellar tissue of aged mice compared with the young LPS and aged controls. Remarkably, senescence (p21, p27, p53) and epigenetic (HDAC2) markers were found upregulated in the cerebellum tissue of the aged LPS group, suggesting their crucial role in LPS-induced cerebellar deficit. Further, we demonstrated alteration in the antagonistic forces of mitochondrial fusion and fission with increased expression of the mitochondrial fission-related gene [FIS1] and decreased fusion-related genes [MFN1 and MFN2]. We noted increased mtDNA copy number, microglia activation, and inflammatory response of IL1β and IFN-γ post-chronic neuroinflammation in aged LPS group. Our results suggest that the crosstalk between mitochondrial dynamics and altered microglial activation paradigm in chronic neuroinflammatory conditions may be the key to understanding the cerebellar molecular mechanism.
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Affiliation(s)
- Devlina Ghosh
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, Gomti Nagar Extension, Lucknow 226028, India; Centre of Biomedical Research, SGPGIMS-Campus, Raibareli Road, Lucknow 226014, India.
| | - Gajendra Singh
- Department of Molecular Medicine and Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Prabhaker Mishra
- Department of Biostatistics and Health Informatics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareli Road, Lucknow 226 014, Uttar Pradesh, India
| | - Aditi Singh
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, Gomti Nagar Extension, Lucknow 226028, India
| | - Alok Kumar
- Department of Molecular Medicine and Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Neeraj Sinha
- Centre of Biomedical Research, SGPGIMS-Campus, Raibareli Road, Lucknow 226014, India.
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13
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Andersen JV, Schousboe A. Glial Glutamine Homeostasis in Health and Disease. Neurochem Res 2023; 48:1100-1128. [PMID: 36322369 DOI: 10.1007/s11064-022-03771-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 08/25/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022]
Abstract
Glutamine is an essential cerebral metabolite. Several critical brain processes are directly linked to glutamine, including ammonia homeostasis, energy metabolism and neurotransmitter recycling. Astrocytes synthesize and release large quantities of glutamine, which is taken up by neurons to replenish the glutamate and GABA neurotransmitter pools. Astrocyte glutamine hereby sustains the glutamate/GABA-glutamine cycle, synaptic transmission and general brain function. Cerebral glutamine homeostasis is linked to the metabolic coupling of neurons and astrocytes, and relies on multiple cellular processes, including TCA cycle function, synaptic transmission and neurotransmitter uptake. Dysregulations of processes related to glutamine homeostasis are associated with several neurological diseases and may mediate excitotoxicity and neurodegeneration. In particular, diminished astrocyte glutamine synthesis is a common neuropathological component, depriving neurons of an essential metabolic substrate and precursor for neurotransmitter synthesis, hereby leading to synaptic dysfunction. While astrocyte glutamine synthesis is quantitatively dominant in the brain, oligodendrocyte-derived glutamine may serve important functions in white matter structures. In this review, the crucial roles of glial glutamine homeostasis in the healthy and diseased brain are discussed. First, we provide an overview of cellular recycling, transport, synthesis and metabolism of glutamine in the brain. These cellular aspects are subsequently discussed in relation to pathological glutamine homeostasis of hepatic encephalopathy, epilepsy, Alzheimer's disease, Huntington's disease and amyotrophic lateral sclerosis. Further studies on the multifaceted roles of cerebral glutamine will not only increase our understanding of the metabolic collaboration between brain cells, but may also aid to reveal much needed therapeutic targets of several neurological pathologies.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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14
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Ameen AO, Freude K, Aldana BI. Fats, Friends or Foes: Investigating the Role of Short- and Medium-Chain Fatty Acids in Alzheimer's Disease. Biomedicines 2022; 10:2778. [PMID: 36359298 PMCID: PMC9687972 DOI: 10.3390/biomedicines10112778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 08/26/2023] Open
Abstract
Characterising Alzheimer's disease (AD) as a metabolic disorder of the brain is gaining acceptance based on the pathophysiological commonalities between AD and major metabolic disorders. Therefore, metabolic interventions have been explored as a strategy for brain energetic rescue. Amongst these, medium-chain fatty acid (MCFA) supplementations have been reported to rescue the energetic failure in brain cells as well as the cognitive decline in patients. Short-chain fatty acids (SCFA) have also been implicated in AD pathology. Due to the increasing therapeutic interest in metabolic interventions and brain energetic rescue in neurodegenerative disorders, in this review, we first summarise the role of SCFAs and MCFAs in AD. We provide a comparison of the main findings regarding these lipid species in established AD animal models and recently developed human cell-based models of this devastating disorder.
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Affiliation(s)
- Aishat O. Ameen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kristine Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark
| | - Blanca I. Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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15
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Chen Z, Yuan Z, Yang S, Zhu Y, Xue M, Zhang J, Leng L. Brain Energy Metabolism: Astrocytes in Neurodegenerative Diseases. CNS Neurosci Ther 2022; 29:24-36. [PMID: 36193573 PMCID: PMC9804080 DOI: 10.1111/cns.13982] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 08/23/2022] [Accepted: 09/11/2022] [Indexed: 02/06/2023] Open
Abstract
Astrocytes are the most abundant cells in the brain. They have many important functions in the central nervous system (CNS), including the maintenance of glutamate and ion homeostasis, the elimination of oxidative stress, energy storage in glycogen, tissue repair, regulating synaptic activity by releasing neurotransmitters, and participating in synaptic formation. Astrocytes have special highly ramified structure. Their branches contact with synapses of neurons inwardly, with fine structure and wrapping synapses; their feet contact with blood vessels of brain parenchyma outward, almost wrapping the whole brain. The adjacent astrocytes rarely overlap and communicate with each other through gap junction channels. The ideal location of astrocytes enables them to sense the weak changes of their surroundings and provide the structural basis for the energy supply of neurons. Neurons and astrocytes are closely coupled units of energy metabolism in the brain. Neurons consume a lot of ATPs in the process of neurotransmission. Astrocytes provide metabolic substrates for neurons, maintain high activity of neuron, and facilitate information transmission of neurons. This article reviews the characteristics of glucose metabolism, lipid metabolism, and amino acid metabolism of astrocytes. The metabolic interactions between astrocytes and neurons, astrocytes and microglia were also detailed discussed. Finally, we classified analyzed the role of metabolic disorder of astrocytes in the occurrence and development of neurodegenerative diseases.
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Affiliation(s)
- Zhenlei Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging ResearchInstitute of Neuroscience, School of Medicine, Xiamen UniversityXiamenChina
| | - Ziqi Yuan
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging ResearchInstitute of Neuroscience, School of Medicine, Xiamen UniversityXiamenChina
| | - Shangchen Yang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging ResearchInstitute of Neuroscience, School of Medicine, Xiamen UniversityXiamenChina
| | - Yufei Zhu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging ResearchInstitute of Neuroscience, School of Medicine, Xiamen UniversityXiamenChina
| | - Maoqiang Xue
- Department of Basic Medical Science, School of MedicineXiamen UniversityXiamenChina
| | - Jie Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging ResearchInstitute of Neuroscience, School of Medicine, Xiamen UniversityXiamenChina
| | - Lige Leng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging ResearchInstitute of Neuroscience, School of Medicine, Xiamen UniversityXiamenChina
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16
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Valappil DK, Mini NJ, Dilna A, Nath S. Membrane interaction to intercellular spread of pathology in Alzheimer’s disease. Front Neurosci 2022; 16:936897. [PMID: 36161178 PMCID: PMC9500529 DOI: 10.3389/fnins.2022.936897] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/24/2022] [Indexed: 11/22/2022] Open
Abstract
Progressive development of pathology is one of the major characteristic features of neurodegenerative diseases. Alzheimer’s disease (AD) is the most prevalent among them. Extracellular amyloid-β (Aβ) plaques and intracellular tau neurofibrillary tangles are the pathological phenotypes of AD. However, cellular and animal studies implicate tau as a secondary pathology in developing AD while Aβ aggregates is considered as a trigger point. Interaction of Aβ peptides with plasma membrane (PM) seems to be a promising site of involvement in the events that lead to AD. Aβ binding to the lipid membranes initiates formation of oligomers of Aβ species, and these oligomers are known as primary toxic agents for neuronal toxicities. Once initiated, neuropathological toxicities spread in a “prion-like” fashion probably through the mechanism of intercellular transfer of pathogenic aggregates. In the last two decades, several studies have demonstrated neuron-to-neuron transfer of neurodegenerative proteins including Aβ and tau via exosomes and tunneling nanotubes (TNTs), the two modes of long-range intercellular transfer. Emerging pieces of evidence indicate that molecular pathways related to the biogenesis of exosomes and TNTs interface with endo-lysosomal pathways and cellular signaling in connection to vesicle recycling-imposed PM and actin remodulation. In this review, we discuss interactions of Aβ aggregates at the membrane level and its implications in intercellular spread of pathogenic aggregates. Furthermore, we hypothesize how spread of pathogenic aggregates contributes to complex molecular events that could regulate pathological and synaptic changes related to AD.
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Affiliation(s)
| | | | | | - Sangeeta Nath
- *Correspondence: Sangeeta Nath, ; orcid.org/0000-0003-0050-0606
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17
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Wang Q, Lu M, Zhu X, Gu X, Zhang T, Xia C, Yang L, Xu Y, Zhou M. The role of microglia immunometabolism in neurodegeneration: Focus on molecular determinants and metabolic intermediates of metabolic reprogramming. Biomed Pharmacother 2022; 153:113412. [DOI: 10.1016/j.biopha.2022.113412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
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18
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Andersen JV, Schousboe A, Verkhratsky A. Astrocyte energy and neurotransmitter metabolism in Alzheimer's disease: integration of the glutamate/GABA-glutamine cycle. Prog Neurobiol 2022; 217:102331. [PMID: 35872221 DOI: 10.1016/j.pneurobio.2022.102331] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/14/2022] [Accepted: 07/19/2022] [Indexed: 02/06/2023]
Abstract
Astrocytes contribute to the complex cellular pathology of Alzheimer's disease (AD). Neurons and astrocytes function in close collaboration through neurotransmitter recycling, collectively known as the glutamate/GABA-glutamine cycle, which is essential to sustain neurotransmission. Neurotransmitter recycling is intimately linked to astrocyte energy metabolism. In the course of AD, astrocytes undergo extensive metabolic remodeling, which may profoundly affect the glutamate/GABA-glutamine cycle. The consequences of altered astrocyte function and metabolism in relation to neurotransmitter recycling are yet to be comprehended. Metabolic alterations of astrocytes in AD deprive neurons of metabolic support, thereby contributing to synaptic dysfunction and neurodegeneration. In addition, several astrocyte-specific components of the glutamate/GABA-glutamine cycle, including glutamine synthesis and synaptic neurotransmitter uptake, are perturbed in AD. Integration of the complex astrocyte biology within the context of AD is essential for understanding the fundamental mechanisms of the disease, while restoring astrocyte metabolism may serve as an approach to arrest or even revert clinical progression of AD.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, 48011 Bilbao, Spain; Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102 Vilnius, Lithuania.
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19
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Rimmele TS, Li S, Andersen JV, Westi EW, Rotenberg A, Wang J, Aldana BI, Selkoe DJ, Aoki CJ, Dulla CG, Rosenberg PA. Neuronal Loss of the Glutamate Transporter GLT-1 Promotes Excitotoxic Injury in the Hippocampus. Front Cell Neurosci 2022; 15:788262. [PMID: 35035352 PMCID: PMC8752461 DOI: 10.3389/fncel.2021.788262] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/08/2021] [Indexed: 12/26/2022] Open
Abstract
GLT-1, the major glutamate transporter in the mammalian central nervous system, is expressed in presynaptic terminals that use glutamate as a neurotransmitter, in addition to astrocytes. It is widely assumed that glutamate homeostasis is regulated primarily by glutamate transporters expressed in astrocytes, leaving the function of GLT-1 in neurons relatively unexplored. We generated conditional GLT-1 knockout (KO) mouse lines to understand the cell-specific functions of GLT-1. We found that stimulus-evoked field extracellular postsynaptic potentials (fEPSPs) recorded in the CA1 region of the hippocampus were normal in the astrocytic GLT-1 KO but were reduced and often absent in the neuronal GLT-1 KO at 40 weeks. The failure of fEPSP generation in the neuronal GLT-1 KO was also observed in slices from 20 weeks old mice but not consistently from 10 weeks old mice. Using an extracellular FRET-based glutamate sensor, we found no difference in stimulus-evoked glutamate accumulation in the neuronal GLT-1 KO, suggesting a postsynaptic cause of the transmission failure. We hypothesized that excitotoxicity underlies the failure of functional recovery of slices from the neuronal GLT-1 KO. Consistent with this hypothesis, the non-competitive NMDA receptor antagonist MK801, when present in the ACSF during the recovery period following cutting of slices, promoted full restoration of fEPSP generation. The inclusion of an enzymatic glutamate scavenging system in the ACSF conferred partial protection. Excitotoxicity might be due to excess release or accumulation of excitatory amino acids, or to metabolic perturbation resulting in increased vulnerability to NMDA receptor activation. Previous studies have demonstrated a defect in the utilization of glutamate by synaptic mitochondria and aspartate production in the synGLT-1 KO in vivo, and we found evidence for similar metabolic perturbations in the slice preparation. In addition, mitochondrial cristae density was higher in synaptic mitochondria in the CA1 region in 20–25 weeks old synGLT-1 KO mice in the CA1 region, suggesting compensation for loss of axon terminal GLT-1 by increased mitochondrial efficiency. These data suggest that GLT-1 expressed in presynaptic terminals serves an important role in the regulation of vulnerability to excitotoxicity, and this regulation may be related to the metabolic role of GLT-1 expressed in glutamatergic axon terminals.
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Affiliation(s)
- Theresa S Rimmele
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States
| | - Shaomin Li
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Jens Velde Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Rotenberg
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States.,Program in Neuroscience, Harvard Medical School, Boston, MA, United States
| | - Jianlin Wang
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States
| | - Blanca Irene Aldana
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Chiye J Aoki
- Center for Neural Science, New York University, NY, United States.,Neuroscience Institute NYU Langone Medical Center, NY, United States
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Paul Allen Rosenberg
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States.,Program in Neuroscience, Harvard Medical School, Boston, MA, United States
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20
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Huang SY, Yang YX, Zhang YR, Kuo K, Li HQ, Shen XN, Chen SD, Chen KL, Dong Q, Tan L, Yu JT. Investigating Causal Relations Between Circulating Metabolites and Alzheimer's Disease: A Mendelian Randomization Study. J Alzheimers Dis 2022; 87:463-477. [PMID: 35275550 DOI: 10.3233/jad-220050] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND Metabolomics is a promising approach that can be used to understand pathophysiological pathways of Alzheimer's disease (AD). However, the causal relationships between metabolism and AD are poorly understood. OBJECTIVE We aimed to investigate the causal association between circulating metabolites and risk of AD through two-sample Mendelian randomization (MR) approach. METHODS Genetic associations with 123 circulating metabolic traits were utilized as exposures. Summary statistics data from International Genomics of Alzheimer's Project was used in primary analysis, including 21,982 AD cases and 41,944 controls. Validation was performed using family history of AD data from UK Biobank (27,696 cases of maternal AD, 14,338 cases of paternal AD, and 272,244 controls). We utilized inverse-variance weighted method as primary method. RESULTS We found significantly increased risks of developing AD per standard deviation increase in the levels of circulating ApoB (odd ratio[OR] = 3.18; 95% confidence interval[CI]: 1.52-6.66, p = 0.0022), glycoprotein acetyls (OR = 1.21; 95% CI: 1.05-1.39, p = 0.0093), total cholesterol (OR = 2.73; 95% CI: 1.41-5.30, p = 0.0030), and low-density lipoprotein (LDL) cholesterol (OR = 2.34; 95% CI: 1.53-3.57, p = 0.0001). Whereas glutamine (OR = 0.81; 95% CI: 0.71-0.92, p = 0.0011) were significantly associated with lower risk of AD. We also detected causal effects of several different composition of LDL fractions on increased AD risk, which has been verified in validation. However, we found no association between circulating high-density lipoprotein cholesterol and AD. CONCLUSION Our findings suggest causal effects of circulating glycoprotein acetyls, ApoB, LDL cholesterol, and serum total cholesterol on higher risk of AD, whereas glutamine showed the protective effect.
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Affiliation(s)
- Shu-Yi Huang
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Yu-Xiang Yang
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Ya-Ru Zhang
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Kevin Kuo
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Hong-Qi Li
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Xue-Ning Shen
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Shi-Dong Chen
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Ke-Liang Chen
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Qiang Dong
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, China
| | - Jin-Tai Yu
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, China
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21
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Quintero ME, Pontes JGDM, Tasic L. Metabolomics in degenerative brain diseases. Brain Res 2021; 1773:147704. [PMID: 34744014 DOI: 10.1016/j.brainres.2021.147704] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 10/18/2021] [Accepted: 10/23/2021] [Indexed: 12/23/2022]
Abstract
Among the most studied diseases that affect the central nervous system are Parkinson's, Alzheimer's, and Huntington's diseases, but the lack of effective biomarkers, accurate diagnosis, and precise treatment for each of them is currently an issue. Due to the contribution of biomarkers in supporting diagnosis, many recent efforts have focused on their identification and validation at the beginning or during the progression of the mental illness. Metabolome reveals the metabolic processes that result from protein activities under the guided gene expression and environmental factors, either in healthy or pathological conditions. In this context, metabolomics has proven to be a valuable approach. Currently, magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) are the most commonly used bioanalytical techniques for metabolomics. MS-assisted profiling is considered the most versatile technique, and the NMR is the most reproductive. However, each one of them has its drawbacks. In this review, we summarized several alterations in metabolites that have been reported for these three classic brain diseases using MS and NMR-based research, which might suggest some possible biomarkers to support the diagnosis and/or new targets for their treatment.
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Affiliation(s)
- Melissa Escobar Quintero
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - João Guilherme de Moraes Pontes
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Ljubica Tasic
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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22
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Andersen JV, Skotte NH, Christensen SK, Polli FS, Shabani M, Markussen KH, Haukedal H, Westi EW, Diaz-delCastillo M, Sun RC, Kohlmeier KA, Schousboe A, Gentry MS, Tanila H, Freude KK, Aldana BI, Mann M, Waagepetersen HS. Hippocampal disruptions of synaptic and astrocyte metabolism are primary events of early amyloid pathology in the 5xFAD mouse model of Alzheimer's disease. Cell Death Dis 2021; 12:954. [PMID: 34657143 PMCID: PMC8520528 DOI: 10.1038/s41419-021-04237-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/14/2021] [Accepted: 09/24/2021] [Indexed: 12/23/2022]
Abstract
Alzheimer’s disease (AD) is an unremitting neurodegenerative disorder characterized by cerebral amyloid-β (Aβ) accumulation and gradual decline in cognitive function. Changes in brain energy metabolism arise in the preclinical phase of AD, suggesting an important metabolic component of early AD pathology. Neurons and astrocytes function in close metabolic collaboration, which is essential for the recycling of neurotransmitters in the synapse. However, this crucial metabolic interplay during the early stages of AD development has not been sufficiently investigated. Here, we provide an integrative analysis of cellular metabolism during the early stages of Aβ accumulation in the cerebral cortex and hippocampus of the 5xFAD mouse model of AD. Our electrophysiological examination revealed an increase in spontaneous excitatory signaling in the 5xFAD hippocampus. This hyperactive neuronal phenotype coincided with decreased hippocampal tricarboxylic acid (TCA) cycle metabolism mapped by stable 13C isotope tracing. Particularly, reduced astrocyte TCA cycle activity and decreased glutamine synthesis led to hampered neuronal GABA synthesis in the 5xFAD hippocampus. In contrast, the cerebral cortex of 5xFAD mice displayed an elevated capacity for oxidative glucose metabolism, which may suggest a metabolic compensation in this brain region. We found limited changes when we explored the brain proteome and metabolome of the 5xFAD mice, supporting that the functional metabolic disturbances between neurons and astrocytes are early primary events in AD pathology. In addition, synaptic mitochondrial and glycolytic function was selectively impaired in the 5xFAD hippocampus, whereas non-synaptic mitochondrial function was maintained. These findings were supported by ultrastructural analyses demonstrating disruptions in mitochondrial morphology, particularly in the 5xFAD hippocampus. Collectively, our study reveals complex regional and cell-specific metabolic adaptations in the early stages of amyloid pathology, which may be fundamental for the progressing synaptic dysfunctions in AD.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Niels H Skotte
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sofie K Christensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip S Polli
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA
| | - Mohammad Shabani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Kia H Markussen
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Henriette Haukedal
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marta Diaz-delCastillo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ramon C Sun
- Markey Cancer Center, Lexington, KY, USA.,Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Kristi A Kohlmeier
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew S Gentry
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, Lexington, KY, USA
| | - Heikki Tanila
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Kristine K Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthias Mann
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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23
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Andersen JV, Westi EW, Jakobsen E, Urruticoechea N, Borges K, Aldana BI. Astrocyte metabolism of the medium-chain fatty acids octanoic acid and decanoic acid promotes GABA synthesis in neurons via elevated glutamine supply. Mol Brain 2021; 14:132. [PMID: 34479615 PMCID: PMC8414667 DOI: 10.1186/s13041-021-00842-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/22/2021] [Indexed: 11/23/2022] Open
Abstract
The medium-chain fatty acids octanoic acid (C8) and decanoic acid (C10) are gaining attention as beneficial brain fuels in several neurological disorders. The protective effects of C8 and C10 have been proposed to be driven by hepatic production of ketone bodies. However, plasma ketone levels correlates poorly with the cerebral effects of C8 and C10, suggesting that additional mechanism are in place. Here we investigated cellular C8 and C10 metabolism in the brain and explored how the protective effects of C8 and C10 may be linked to cellular metabolism. Using dynamic isotope labeling, with [U-13C]C8 and [U-13C]C10 as metabolic substrates, we show that both C8 and C10 are oxidatively metabolized in mouse brain slices. The 13C enrichment from metabolism of [U-13C]C8 and [U-13C]C10 was particularly prominent in glutamine, suggesting that C8 and C10 metabolism primarily occurs in astrocytes. This finding was corroborated in cultured astrocytes in which C8 increased the respiration linked to ATP production, whereas C10 elevated the mitochondrial proton leak. When C8 and C10 were provided together as metabolic substrates in brain slices, metabolism of C10 was predominant over that of C8. Furthermore, metabolism of both [U-13C]C8 and [U-13C]C10 was unaffected by etomoxir indicating that it is independent of carnitine palmitoyltransferase I (CPT-1). Finally, we show that inhibition of glutamine synthesis selectively reduced 13C accumulation in GABA from [U-13C]C8 and [U-13C]C10 metabolism in brain slices, demonstrating that the glutamine generated from astrocyte C8 and C10 metabolism is utilized for neuronal GABA synthesis. Collectively, the results show that cerebral C8 and C10 metabolism is linked to the metabolic coupling of neurons and astrocytes, which may serve as a protective metabolic mechanism of C8 and C10 supplementation in neurological disorders.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen E, Denmark.
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen E, Denmark
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen E, Denmark
| | - Nerea Urruticoechea
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen E, Denmark
| | - Karin Borges
- Department of Pharmacology, School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen E, Denmark.
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24
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Jakobsen E, Andersen JV, Christensen SK, Siamka O, Larsen MR, Waagepetersen HS, Aldana BI, Bak LK. Pharmacological inhibition of mitochondrial soluble adenylyl cyclase in astrocytes causes activation of AMP-activated protein kinase and induces breakdown of glycogen. Glia 2021; 69:2828-2844. [PMID: 34378239 DOI: 10.1002/glia.24072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/28/2021] [Accepted: 07/30/2021] [Indexed: 12/17/2022]
Abstract
Mobilization of astrocyte glycogen is key for processes such as synaptic plasticity and memory formation but the link between neuronal activity and glycogen breakdown is not fully known. Activation of cytosolic soluble adenylyl cyclase (sAC) in astrocytes has been suggested to link neuronal depolarization and glycogen breakdown partly based on experiments employing pharmacological inhibition of sAC. However, several studies have revealed that sAC located within mitochondria is a central regulator of respiration and oxidative phosphorylation. Thus, pharmacological sAC inhibition is likely to affect both cytosolic and mitochondrial sAC and if bioenergetic readouts are studied, the observed effects are likely to stem from inhibition of mitochondrial rather than cytosolic sAC. Here, we report that a pharmacologically induced inhibition of sAC activity lowers mitochondrial respiration, induces phosphorylation of the metabolic master switch AMP-activated protein kinase (AMPK), and decreases glycogen stores in cultured primary murine astrocytes. From these data and our discussion of the literature, mitochondrial sAC emerges as a key regulator of astrocyte bioenergetics. Lastly, we discuss the challenges of investigating the functional and metabolic roles of cytosolic versus mitochondrial sAC in astrocytes employing the currently available pharmacological tool compounds.
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Affiliation(s)
- Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sofie K Christensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Olga Siamka
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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25
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Tams ALM, Sanz-Morello B, Westi EW, Mouhammad ZA, Andersen JV, Freude KK, Vohra R, Hannibal J, Aldana BI, Kolko M. Decreased Glucose Metabolism and Glutamine Synthesis in the Retina of a Transgenic Mouse Model of Alzheimer's Disease. Cell Mol Neurobiol 2021; 42:291-303. [PMID: 34259962 DOI: 10.1007/s10571-021-01126-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/05/2021] [Indexed: 12/17/2022]
Abstract
Visual changes are some of the earliest symptoms that patients with Alzheimer's disease (AD) experience. Pathophysiological processes such as amyloid-β plaque formation, vascular changes, neuroinflammation, and loss of retinal ganglion cells (RGCs) have been detected in the retina of AD patients and animal models. However, little is known about the molecular processes that underlie retinal neurodegeneration in AD. The cellular architecture and constant sensory activity of the retina impose high metabolic demands. We thus hypothesized that energy metabolism might be compromised in the AD retina similarly to what has been observed in the AD brain. To address this question, we explored cellular alterations and retinal metabolic activity in the 5 × FAD mouse model of AD. We used 8-month-old female 5 × FAD mice, in which the AD-related pathology has been shown to be apparent. We observed that RGC density is selectively affected in the retina of 5 × FAD mice. To map retinal metabolic activity, we incubated isolated retinal tissue with [U-13C] glucose and analyzed tissue extracts by gas chromatography-mass spectrometry. We found that the retinas of 5 × FAD mice exhibit glucose hypometabolism. Moreover, we detected decreased glutamine synthesis in 5 × FAD retinas but no changes in the expression of markers of Müller glia, the main glial cell type responsible for glutamate uptake and glutamine synthesis in the retina. These findings suggest that AD presents with metabolic alterations not only in the brain but also in the retina that may be detrimental to RGC activity and survival, potentially leading to the visual impairments that AD patients suffer.
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Affiliation(s)
- Anna Luna Mølgaard Tams
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Berta Sanz-Morello
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Emil Winther Westi
- Neurometabolism Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Zaynab Ahmad Mouhammad
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jens Velde Andersen
- Neurometabolism Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Kristine Karla Freude
- Group of Stem Cells and Modeling of Neurodegeneration, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Rupali Vohra
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Group of Stem Cells and Modeling of Neurodegeneration, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Blanca Irene Aldana
- Neurometabolism Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Miriam Kolko
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark. .,Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark.
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26
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Fan S, Li L, Xian X, Liu L, Gao J, Li W. Ceftriaxone regulates glutamate production and vesicular assembly in presynaptic terminals through GLT-1 in APP/PS1 mice. Neurobiol Learn Mem 2021; 183:107480. [PMID: 34153453 DOI: 10.1016/j.nlm.2021.107480] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 05/13/2021] [Accepted: 06/16/2021] [Indexed: 10/21/2022]
Abstract
Perturbations in the glutamate-glutamine cycle and glutamate release from presynaptic terminals have been involved in the development of cognitive deficits in Alzheimer's disease (AD) patients and mouse models. Glutamate transporter-1 (GLT-1) removes glutamate from the synaptic cleft and transports it into astrocytes, where it is used as substrate for the glutamate-glutamine cycle. Ceftriaxone has been reported to improve cognitive deficits in AD mice by increasing GLT-1 expression, glutamate transformation to glutamine, and glutamine efflux from astrocytes. However, the impact of ceftriaxone on glutamine metabolism in neurons is unknown. The present study aimed to investigate whether ceftriaxone regulated the production and vesicular assembly of glutamate in the presynaptic terminals of neurons and to determine GLT-1 involvement in this process. We used the amyloid precursor protein (APP)/presenilin-1 (PS1) AD mouse model and GLT-1 knockdown APP/PS1 (GLT-1+/-/APP/PS1) mice. The expression levels of sodium-coupled neutral amino-acid transporter 1 (SNAT1) and vesicular glutamate transporters 1 and 2 (VGLUT1/2) were analyzed by immunofluorescence and immunohistochemistry staining as well as by Western blotting. Glutaminase activity was assayed by fluorometry. Ceftriaxone treatment significantly increased SNAT1 expression and glutaminase activity in neurons in APP/PS1 mice. Similarly, VGLUT1/2 levels were increased in the presynaptic terminals of APP/PS1 mice treated with ceftriaxone. The deletion of one GLT-1 allele in APP/PS1 mice prevented the ceftriaxone-induced upregulation of SNAT1 and VGLUT1/2 expression, indicating that GLT-1 played an important role in ceftriaxone effect. Based on the role of SNAT1, glutaminase, and VGLUT1/2 in the glutamate-glutamine cycle in neurons, the present results suggested that ceftriaxone improved the production and vesicular assembly of glutamate as a neurotransmitter in presynaptic terminals by acting on GLT-1 in APP/PS1 mice.
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Affiliation(s)
- ShuJuan Fan
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, PR China
| | - Li Li
- Central Laboratory, The Second Hospital of Hebei Medical University, 215 Heping West Road, Shijiazhuang 050000, PR China
| | - XiaoHui Xian
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, PR China.
| | - LiRong Liu
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, PR China
| | - JunXia Gao
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, PR China
| | - WenBin Li
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, PR China.
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27
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Salcedo C, Wagner A, Andersen JV, Vinten KT, Waagepetersen HS, Schousboe A, Freude KK, Aldana BI. Downregulation of GABA Transporter 3 (GAT3) is Associated with Deficient Oxidative GABA Metabolism in Human Induced Pluripotent Stem Cell-Derived Astrocytes in Alzheimer's Disease. Neurochem Res 2021; 46:2676-2686. [PMID: 33710537 DOI: 10.1007/s11064-021-03276-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/15/2021] [Accepted: 02/15/2021] [Indexed: 10/21/2022]
Abstract
Alterations in neurotransmitter homeostasis, primarily of glutamate and GABA, is strongly implicated in the pathophysiology of Alzheimer's disease (AD). Homeostasis at the synapse is maintained by neurotransmitter recycling between neurons and astrocytes. Astrocytes support neuronal transmission through glutamine synthesis, which can be derived from oxidative metabolism of GABA. However, the precise implications of astrocytic GABA metabolism in AD remains elusive. The aim of this study was to investigate astrocytic GABA metabolism in AD pathology implementing human induced pluripotent stem cells derived astrocytes. Metabolic mapping of GABA was performed with [U-13C]GABA stable isotopic labeling using gas chromatography coupled to mass spectrometry (GC-MS). Neurotransmitter and amino acid content was quantified via high performance liquid chromatography (HPLC) and protein expression was investigated by Western blot assay. Cell lines carrying mutations in either amyloid precursor protein (APP) or presenilin1 (PSEN-1) were used as AD models and were compared to a control cell line of the same genetic background. AD astrocytes displayed a reduced oxidative GABA metabolism mediated by a decreased uptake capacity of GABA, as GABA transporter 3 (GAT3) was downregulated in AD astrocytes compared to the controls. Interestingly, the carbon backbone of GABA in AD astrocytes was utilized to a larger extent to support glutamine synthesis compared to control astrocytes. The results strongly indicate alterations in GABA uptake and metabolism in AD astrocytes linked to reduced GABA transporter expression, hereby contributing further to neurotransmitter disturbances.
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Affiliation(s)
- Claudia Salcedo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Antonie Wagner
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Kasper Tore Vinten
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Kristine K Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
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28
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Bridging the Metabolic Parallels Between Neurological Diseases and Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1311:229-248. [PMID: 34014547 DOI: 10.1007/978-3-030-65768-0_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite the many recent breakthroughs in cancer research, oncology has traditionally been seen as a distinct field from other diseases. Recently, more attention has been paid to repurposing established therapeutic strategies and targets of other diseases towards cancer treatment, with some of these attempts generating promising outcomes [1, 2]. Recent studies using advanced metabolomics technologies [3] have shown evidence of close metabolic similarities between cancer and neurological diseases. These studies have unveiled several metabolic characteristics shared by these two categories of diseases, including metabolism of glutamine, gamma-aminobutyric acid (GABA), and N-acetyl-aspartyl-glutamate (NAAG) [4-6]. The striking metabolic overlap between cancer and neurological diseases sheds light on novel therapeutic strategies for cancer treatment. For example, 2-(phosphonomethyl) pentanedioic acid (2-PMPA), one of the glutamate carboxypeptidase II (GCP II) inhibitors that prevent the conversion of NAAG to glutamate, has been shown to suppress cancer growth [6, 7]. These promising results have led to an increased interest in integrating this metabolic overlap between cancer and neurological diseases into the study of cancer metabolism. The advantages of studying this metabolic overlap include not only drug repurposing but also translating existing knowledge from neurological diseases to the field of cancer research. This chapter discusses the specific overlapping metabolic features between cancer and neurological diseases, focusing on glutamine, GABA, and NAAG metabolisms. Understanding the interconnections between cancer and neurological diseases will guide researchers and clinicians to find more effective cancer treatments.
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29
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Andersen JV, Christensen SK, Westi EW, Diaz-delCastillo M, Tanila H, Schousboe A, Aldana BI, Waagepetersen HS. Deficient astrocyte metabolism impairs glutamine synthesis and neurotransmitter homeostasis in a mouse model of Alzheimer's disease. Neurobiol Dis 2020; 148:105198. [PMID: 33242587 DOI: 10.1016/j.nbd.2020.105198] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) leads to cerebral accumulation of insoluble amyloid-β plaques causing synaptic dysfunction and neuronal death. Neurons rely on astrocyte-derived glutamine for replenishment of the amino acid neurotransmitter pools. Perturbations of astrocyte glutamine synthesis have been described in AD, but whether this functionally affects neuronal neurotransmitter synthesis is not known. Since the synthesis and recycling of neurotransmitter glutamate and GABA are intimately coupled to cellular metabolism, the aim of this study was to provide a functional investigation of neuronal and astrocytic energy and neurotransmitter metabolism in AD. To achieve this, we incubated acutely isolated cerebral cortical and hippocampal slices from 8-month-old female 5xFAD mice, in the presence of 13C isotopically enriched substrates, with subsequent gas chromatography-mass spectrometry (GC-MS) analysis. A prominent neuronal hypometabolism of [U-13C]glucose was observed in the hippocampal slices of the 5xFAD mice. Investigating astrocyte metabolism, using [1,2-13C]acetate, revealed a marked reduction in glutamine synthesis, which directly hampered neuronal synthesis of GABA. This was supported by an increased metabolism of exogenously supplied [U-13C]glutamine, suggesting a neuronal metabolic compensation of the reduced astrocytic glutamine supply. In contrast, astrocytic metabolism of [U-13C]GABA was reduced, whereas [U-13C]glutamate metabolism was unaffected. Finally, astrocyte de novo synthesis of glutamate and glutamine was hampered, whereas the enzymatic capacity of glutamine synthetase for ammonia fixation was maintained. Collectively, we demonstrate that deficient astrocyte metabolism leads to reduced glutamine synthesis, directly impairing neuronal GABA synthesis in the 5xFAD brain. These findings suggest that astrocyte metabolic dysfunction may be fundamental for the imbalances of synaptic excitation and inhibition in the AD brain.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Sofie K Christensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Marta Diaz-delCastillo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Heikki Tanila
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Bukke VN, Archana M, Villani R, Romano AD, Wawrzyniak A, Balawender K, Orkisz S, Beggiato S, Serviddio G, Cassano T. The Dual Role of Glutamatergic Neurotransmission in Alzheimer's Disease: From Pathophysiology to Pharmacotherapy. Int J Mol Sci 2020; 21:ijms21207452. [PMID: 33050345 PMCID: PMC7589203 DOI: 10.3390/ijms21207452] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related dementia and neurodegenerative disorder, characterized by Aβ and tau protein deposition impairing learning, memory and suppressing synaptic plasticity of neurons. Increasing evidence suggests that there is a link between the glucose and glutamate alterations with age that down-regulates glucose utilization reducing glutamate levels in AD patients. Deviations in brain energy metabolism reinforce the development of AD by hampering glutamate levels in the brain. Glutamate is a nonessential amino acid and the major excitatory neurotransmitter synthesized from glucose. Alterations in cerebral glucose and glutamate levels precede the deposition of Aβ plaques. In the brain, over 40% of neuronal synapses are glutamatergic and disturbances in glutamatergic function have been implicated in pathophysiology of AD. Nevertheless, targeting the glutamatergic system seems to be a promising strategy to develop novel, improved therapeutics for AD. Here, we review data supporting the involvement of the glutamatergic system in AD pathophysiology as well as the efficacy of glutamatergic agents in this neurodegenerative disorder. We also discuss exciting new prospects for the development of improved therapeutics for this devastating disorder.
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Affiliation(s)
- Vidyasagar Naik Bukke
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
| | - Moola Archana
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Rosanna Villani
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Antonino Davide Romano
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Agata Wawrzyniak
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Krzysztof Balawender
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Stanislaw Orkisz
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Sarah Beggiato
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100 Chieti, Italy;
| | - Gaetano Serviddio
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
- Correspondence:
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Shippy DC, Ulland TK. Microglial Immunometabolism in Alzheimer's Disease. Front Cell Neurosci 2020; 14:563446. [PMID: 33192310 PMCID: PMC7531234 DOI: 10.3389/fncel.2020.563446] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/28/2020] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by amyloid-β (Aβ) plaques and the formation of neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau. In response to Aβ and tau aggregates, microglia, the primary innate immune cells of the central nervous system (CNS), facilitate Aβ and tau clearance and contribute to neuroinflammation that damages neurons. Microglia also perform a wide range of other functions, e.g., synaptic pruning, within the CNS that require a large amount of energy. Glucose appears to be the primary energy source, but microglia can utilize several other substrates for energy production including other sugars and ketone bodies. Recent studies have demonstrated that changes in the metabolic profiles of immune cells, including macrophages, are important in controlling their activation and effector functions. Additional studies have focused on the role of metabolism in neuron and astrocyte function while until recently microglia metabolism has been considerably less well understood. Considering many neurological disorders, such as neurodegeneration associated with AD, are associated with chronic inflammation and alterations in brain energy metabolism, it is hypothesized that microglial metabolism plays a significant role in the inflammatory responses of microglia during neurodegeneration. Here, we review the role of microglial immunometabolism in AD.
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Affiliation(s)
- Daniel C Shippy
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, United States
| | - Tyler K Ulland
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, United States
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Glutamate-glutamine homeostasis is perturbed in neurons and astrocytes derived from patient iPSC models of frontotemporal dementia. Mol Brain 2020; 13:125. [PMID: 32928252 PMCID: PMC7491073 DOI: 10.1186/s13041-020-00658-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023] Open
Abstract
Frontotemporal dementia (FTD) is amongst the most prevalent early onset dementias and even though it is clinically, pathologically and genetically heterogeneous, a crucial involvement of metabolic perturbations in FTD pathology is being recognized. However, changes in metabolism at the cellular level, implicated in FTD and in neurodegeneration in general, are still poorly understood. Here we generate induced human pluripotent stem cells (hiPSCs) from patients carrying mutations in CHMP2B (FTD3) and isogenic controls generated via CRISPR/Cas9 gene editing with subsequent neuronal and glial differentiation and characterization. FTD3 neurons show a dysregulation of glutamate-glutamine related metabolic pathways mapped by 13C-labelling coupled to mass spectrometry. FTD3 astrocytes show increased uptake of glutamate whilst glutamate metabolism is largely maintained. Using quantitative proteomics and live-cell metabolic analyses, we elucidate molecular determinants and functional alterations of neuronal and glial energy metabolism in FTD3. Importantly, correction of the mutations rescues such pathological phenotypes. Notably, these findings implicate dysregulation of key enzymes crucial for glutamate-glutamine homeostasis in FTD3 pathogenesis which may underlie vulnerability to neurodegeneration. Neurons derived from human induced pluripotent stem cells (hiPSCs) of patients carrying mutations in CHMP2B (FTD3) display major metabolic alterations compared to CRISPR/Cas9 generated isogenic controls. Using quantitative proteomics, 13C-labelling coupled to mass spectrometry metabolic mapping and seahorse analyses, molecular determinants and functional alterations of neuronal and astrocytic energy metabolism in FTD3 were characterized. Our findings implicate dysregulation of glutamate-glutamine homeostasis in FTD3 pathogenesis. In addition, FTD3 neurons recapitulate glucose hypometabolism observed in FTD patient brains. The impaired mitochondria function found here is concordant with disturbed TCA cycle activity and decreased glycolysis in FTD3 neurons. FTD3 neuronal glutamine hypermetabolism is associated with up-regulation of PAG expression and, possibly, ROS production. Distinct compartments of glutamate metabolism can be suggested for the FTD3 neurons. Endogenous glutamate generated from glutamine via PAG may enter the TCA cycle via AAT (left side of neuron) while exogenous glutamate taken up from the extracellular space may be incorporated into the TCA cycle via GDH (right side of the neuron) FTD3 astrocytic glutamate uptake is upregulated whilst glutamate metabolism is largely maintained. Finally, pharmacological reversal of glutamate hypometabolism manifesting from decreased GDH expression should be explored as a novel therapeutic intervention for treating FTD3.
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Abstract
Alzheimer's disease (AD) and Parkinson's disease (PD) are, respectively, the most prevalent and fastest growing neurodegenerative diseases worldwide. The former is primarily characterized by memory loss and the latter by the motor symptoms of tremor and bradykinesia. Both AD and PD are progressive diseases that share several key underlying mitochondrial, inflammatory, and other metabolic pathologies. This review will detail how these pathologies intersect with ketone body metabolism and signaling, and how ketone bodies, particularly d-β-hydroxybutyrate (βHB), may serve as a potential adjunctive nutritional therapy for two of the world's most devastating conditions.
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34
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Rodríguez-Gómez JA, Kavanagh E, Engskog-Vlachos P, Engskog MK, Herrera AJ, Espinosa-Oliva AM, Joseph B, Hajji N, Venero JL, Burguillos MA. Microglia: Agents of the CNS Pro-Inflammatory Response. Cells 2020; 9:E1717. [PMID: 32709045 PMCID: PMC7407646 DOI: 10.3390/cells9071717] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/21/2022] Open
Abstract
The pro-inflammatory immune response driven by microglia is a key contributor to the pathogenesis of several neurodegenerative diseases. Though the research of microglia spans over a century, the last two decades have increased our understanding exponentially. Here, we discuss the phenotypic transformation from homeostatic microglia towards reactive microglia, initiated by specific ligand binding to pattern recognition receptors including toll-like receptor-4 (TLR4) or triggering receptors expressed on myeloid cells-2 (TREM2), as well as pro-inflammatory signaling pathways triggered such as the caspase-mediated immune response. Additionally, new research disciplines such as epigenetics and immunometabolism have provided us with a more holistic view of how changes in DNA methylation, microRNAs, and the metabolome may influence the pro-inflammatory response. This review aimed to discuss our current knowledge of pro-inflammatory microglia from different angles, including recent research highlights such as the role of exosomes in spreading neuroinflammation and emerging techniques in microglia research including positron emission tomography (PET) scanning and the use of human microglia generated from induced pluripotent stem cells (iPSCs). Finally, we also discuss current thoughts on the impact of pro-inflammatory microglia in neurodegenerative diseases.
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Affiliation(s)
- José A. Rodríguez-Gómez
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Medical Physiology and Biophysics, Faculty of Medicine, University of Seville, 41009 Sevilla, Spain
| | - Edel Kavanagh
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Pinelopi Engskog-Vlachos
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institute, 17177 Stockholm, Sweden; (P.E.-V.); (B.J.)
| | - Mikael K.R. Engskog
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden;
| | - Antonio J. Herrera
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Ana M. Espinosa-Oliva
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Bertrand Joseph
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institute, 17177 Stockholm, Sweden; (P.E.-V.); (B.J.)
| | - Nabil Hajji
- Division of Brain Sciences, The John Fulcher Molecular Neuro-Oncology Laboratory, Imperial College London, London W12 ONN, UK;
| | - José L. Venero
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Miguel A. Burguillos
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
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35
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Jiang W, Xu S, Guo H, Lu L, Liu J, Wang G, Hao K. Magnesium isoglycyrrhizinate prevents the nonalcoholic hepatic steatosis via regulating energy homeostasis. J Cell Mol Med 2020; 24:7201-7213. [PMID: 32410294 PMCID: PMC7339216 DOI: 10.1111/jcmm.15230] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/22/2020] [Accepted: 03/06/2020] [Indexed: 12/21/2022] Open
Abstract
Non-alcoholic fatty liver disease is a public health problem worldwide associated with high morbidity and hepatic steatosis, but no effective therapeutic interventions. Magnesium isoglycyrrhizinate (MGIG), a derivative of an active component of Glycyrrhiza glabra, is widely used for the treatment of inflammatory liver diseases due to its potent anti-inflammatory and hepatoprotective activities. Hence, this study aimed to study the effects of MGIG on hepatic steatosis in mice fed a high-fat diet (HFD). Oil Red O staining and transmission electron microscopy revealed a decrease in lipid accumulation in the liver after MGIG treatment along with improved mitochondrial ultramicrostructures. Metabonomic analysis demonstrated that MGIG intervention increased glutamate utilization in mitochondria by promoting the uptake of glutamate into the tricarboxylic acid (TCA) cycle. The NAD+ /NADH ratio and the expression of other lipid-metabolism-related genes were increased in MGIG-treated livers. Transcriptome sequencing showed that the expression of TLR4, an isoform of the innate immunity Toll-like receptors (TLRs), was significantly decreased after MGIG treatment, suggesting a link between the anti-inflammatory effects of MGIG and its suppression of lipidation. Our results reveal the potent effects of MGIG on lipid metabolism and suggest that hepatic TLR4 might be a crucial therapeutic target to regulate energy homeostasis in hepatic steatosis.
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Affiliation(s)
- Wenjiao Jiang
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
| | - Shiyu Xu
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
| | - Huijie Guo
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
| | - Li Lu
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
| | - Jie Liu
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
| | - Guangji Wang
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
| | - Kun Hao
- Key Laboratory of Drug Metabolism and PharmacokineticsChina Pharmaceutical UniversityNanjingChina
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36
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Andersen JV, Jakobsen E, Westi EW, Lie MEK, Voss CM, Aldana BI, Schousboe A, Wellendorph P, Bak LK, Pinborg LH, Waagepetersen HS. Extensive astrocyte metabolism of γ-aminobutyric acid (GABA) sustains glutamine synthesis in the mammalian cerebral cortex. Glia 2020; 68:2601-2612. [PMID: 32584476 DOI: 10.1002/glia.23872] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022]
Abstract
Synaptic transmission is closely linked to brain energy and neurotransmitter metabolism. However, the extent of brain metabolism of the inhibitory neurotransmitter γ-aminobutyric acid (GABA), and the relative metabolic contributions of neurons and astrocytes, are yet unknown. The present study was designed to investigate the functional significance of brain GABA metabolism using isolated mouse cerebral cortical slices and slices of neurosurgically resected neocortical human tissue of the temporal lobe. By using dynamic isotope labeling, with [15 N]GABA and [U-13 C]GABA as metabolic substrates, we show that both mouse and human brain slices exhibit a large capacity for GABA metabolism. Both the nitrogen and the carbon backbone of GABA strongly support glutamine synthesis, particularly in the human cerebral cortex, indicative of active astrocytic GABA metabolism. This was further substantiated by pharmacological inhibition of the primary astrocytic GABA transporter subtype 3 (GAT3), by (S)-SNAP-5114 or 1-benzyl-5-chloro-2,3-dihydro-1H-indole-2,3-dione (compound 34), leading to significant reductions in oxidative GABA carbon metabolism. Interestingly, this was not the case when tiagabine was used to specifically inhibit GAT1, which is predominantly found on neurons. Finally, we show that acute GABA exposure does not directly stimulate glycolytic activity nor oxidative metabolism in cultured astrocytes, but can be used as an additional substrate to enhance uncoupled respiration. These results clearly show that GABA is actively metabolized in astrocytes, particularly for the synthesis of glutamine, and challenge the current view that synaptic GABA homeostasis is maintained primarily by presynaptic recycling.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria E K Lie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline M Voss
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lars H Pinborg
- Epilepsy Clinic and Neurobiology Research Unit, Copenhagen University Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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37
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Cui M, Jiang Y, Zhao Q, Zhu Z, Liang X, Zhang K, Wu W, Dong Q, An Y, Tang H, Ding D, Chen X. Metabolomics and incident dementia in older Chinese adults: The Shanghai Aging Study. Alzheimers Dement 2020; 16:779-788. [PMID: 32270572 DOI: 10.1002/alz.12074] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/27/2019] [Accepted: 01/03/2020] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Metabolomics provide a promising tool to understand the pathogenesis and to identify novel biomarkers of dementia. This study aimed to determine circulating metabolites associated with incident dementia in a Chinese cohort, and whether a selected metabolite panel could predict dementia. METHODS Thirty-eight metabolites in baseline serum were profiled by nuclear magnetic resonance in 1440 dementia-free participants followed 5 years in the Shanghai Aging Study. RESULTS Higher serum levels of glutamine and O-acetyl-glycoproteins were associated with increased risk of dementia, whereas glutamate, tyrosine, acetate, glycine, and phenylalanine were negatively related to incident dementia. A panel of five metabolites selected by least absolute shrinkage and selection operator within cross-validation regression analysis could predict incident dementia with an area under the receiver-operating characteristic curve of 0.72. DISCUSSION We identified seven candidate serum metabolic biomarkers for dementia. These findings and the underlying biological mechanisms need to be further replicated and elucidated in future studies.
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Affiliation(s)
- Mei Cui
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yanfeng Jiang
- State Key Laboratory of Genetic Engineering, Human Phenome Institute, Fudan University, Shanghai, China.,School of Life Sciences, Fudan University, Shanghai, China.,Fudan University Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
| | - Qianhua Zhao
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhen Zhu
- Fudan University Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China.,Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China
| | - Xiaoniu Liang
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Kexun Zhang
- Fudan University Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China.,Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China
| | - Wanqing Wu
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Qiang Dong
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yanpeng An
- Metabonomics and Systems Biology Laboratory, School of Life Sciences, Fudan University, Shanghai, China
| | - Huiru Tang
- Metabonomics and Systems Biology Laboratory, School of Life Sciences, Fudan University, Shanghai, China
| | - Ding Ding
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xingdong Chen
- State Key Laboratory of Genetic Engineering, Human Phenome Institute, Fudan University, Shanghai, China.,School of Life Sciences, Fudan University, Shanghai, China.,Fudan University Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
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38
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Conditional Knockout of GLT-1 in Neurons Leads to Alterations in Aspartate Homeostasis and Synaptic Mitochondrial Metabolism in Striatum and Hippocampus. Neurochem Res 2020; 45:1420-1437. [PMID: 32144526 DOI: 10.1007/s11064-020-03000-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/06/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
Expression of the glutamate transporter GLT-1 in neurons has been shown to be important for synaptic mitochondrial function in the cerebral cortex. Here we determined whether neuronal GLT-1 plays a similar role in the hippocampus and striatum, using conditional GLT-1 knockout mice in which GLT-1 was inactivated in neurons by expression of synapsin-Cre (synGLT-1 KO). Ex vivo 13C-labelling using [1,2-13C]acetate, representing astrocytic metabolism, yielded increased [4,5-13C]glutamate levels, suggesting increased astrocyte-neuron glutamine transfer, in the striatum but not in the hippocampus of the synGLT-1 KO. Moreover, aspartate concentrations were reduced - 38% compared to controls in the hippocampus and the striatum of the synGLT-1 KO. Mitochondria isolated from the hippocampus of synGLT-1 KO mice exhibited a lower oxygen consumption rate in the presence of oligomycin A, indicative of a decreased proton leak across the mitochondrial membrane, whereas the ATP production rate was unchanged. Electron microscopy revealed reduced mitochondrial inter-cristae distance within excitatory synaptic terminals in the hippocampus and striatum of the synGLT-1 KO. Finally, dilution of 13C-labelling originating from [U-13C]glucose, caused by metabolism of unlabelled glutamate, was reduced in hippocampal synGLT-1 KO synaptosomes, suggesting that neuronal GLT-1 provides glutamate for synaptic tricarboxylic acid cycle metabolism. Collectively, these data demonstrate an important role of neuronal expression of GLT-1 in synaptic mitochondrial metabolism in the forebrain.
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39
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Voss CM, Andersen JV, Jakobsen E, Siamka O, Karaca M, Maechler P, Waagepetersen HS. AMP-activated protein kinase (AMPK) regulates astrocyte oxidative metabolism by balancing TCA cycle dynamics. Glia 2020; 68:1824-1839. [PMID: 32092215 DOI: 10.1002/glia.23808] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/12/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Abstract
AMP-activated protein kinase (AMPK) is an important energy sensor located in cells throughout the human body. From the periphery, AMPK is known to be a metabolic master switch controlling the use of energy fuels. The energy sensor is activated when the energy status of the cell is low, initiating energy-producing pathways and deactivating energy-consuming pathways. All brain cells are crucially dependent on energy production for survival, and the availability of energy substrates must be closely regulated. Intriguingly, the role of AMPK in the regulation of brain cell metabolism has been sparsely investigated, particularly in astrocytes. By investigating metabolism of 13 C-labeled energy substrates in acutely isolated hippocampal slices and cultured astrocytes, with subsequent mass spectrometry analysis, we here show that activation of AMPK increases glycolysis as well as the capacity of the TCA cycle, that is, anaplerosis, through the activity of pyruvate carboxylase (PC) in astrocytes. In addition, we demonstrate that AMPK activation leads to augmented astrocytic glutamate oxidation via pyruvate recycling (i.e., cataplerosis). This regulatory mechanism induced by AMPK activation is mediated via glutamate dehydrogenase (GDH) shown in a CNS-specific GDH knockout mouse. Collectively, these findings demonstrate that AMPK regulates TCA cycle dynamics in astrocytes via PC and GDH activity. AMPK functionality has been shown to be hampered in Alzheimer's and Parkinson's disease and our findings may therefore add to the toolbox for discovery of new metabolic drug targets.
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Affiliation(s)
- Caroline M Voss
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Olga Siamka
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Melis Karaca
- Department of Cell Physiology and Metabolism, CMU, University of Geneva, Geneva, Switzerland
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, CMU, University of Geneva, Geneva, Switzerland
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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40
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Tondo M, Wasek B, Escola-Gil JC, de Gonzalo-Calvo D, Harmon C, Arning E, Bottiglieri T. Altered Brain Metabolome Is Associated with Memory Impairment in the rTg4510 Mouse Model of Tauopathy. Metabolites 2020; 10:metabo10020069. [PMID: 32075035 PMCID: PMC7074477 DOI: 10.3390/metabo10020069] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/01/2020] [Accepted: 02/05/2020] [Indexed: 01/03/2023] Open
Abstract
Alzheimer’s disease (AD) is characterized, amongst other features, by the pathologic accumulation of abnormally phosphorylated tau filaments in neurons that lead to neurofibrillary tangles. However, the molecular mechanisms by which the abnormal processing of tau leads to neurodegeneration and cognitive impairment remain unknown. Metabolomic techniques can comprehensively assess disturbances in metabolic pathways that reflect changes downstream from genomic, transcriptomic and proteomic systems. In the present study, we undertook a targeted metabolomic approach to determine a total of 187 prenominated metabolites in brain cortex tissue from wild type and rTg4510 animals (a mice model of tauopathy), in order to establish the association of metabolic pathways with cognitive impairment. This targeted metabolomic approach revealed significant differences in metabolite concentrations of transgenic mice. Brain glutamine, serotonin and sphingomyelin C18:0 were found to be predictors of memory impairment. These findings provide informative data for future research on AD, since some of them agree with pathological alterations observed in diseased humans.
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Affiliation(s)
- Mireia Tondo
- Center of Metabolomics, Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX 75226, USA; (M.T.); (B.W.); (C.H.); (E.A.)
- Servei de Bioquímica, Laboratori Sant Pau, Hospital de la Santa Creu i Sant Pau, 08041 Barcelona, Spain
| | - Brandi Wasek
- Center of Metabolomics, Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX 75226, USA; (M.T.); (B.W.); (C.H.); (E.A.)
| | - Joan Carles Escola-Gil
- Research Institute, Hospital de la Santa Creu i Sant Pau and CIBERDEM, Institute of Health Carlos III, 08041 Barcelona, Spain;
| | - David de Gonzalo-Calvo
- Institute of Biomedical Research of Barcelona (IIBB)—Spanish National Research Council (CSIC), Biomedical Research Institute Sant Pau (IIB Sant Pau) and CIBERCV, Institute of Health Carlos III, 08036 Barcelona, Spain;
| | - Clinton Harmon
- Center of Metabolomics, Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX 75226, USA; (M.T.); (B.W.); (C.H.); (E.A.)
| | - Erland Arning
- Center of Metabolomics, Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX 75226, USA; (M.T.); (B.W.); (C.H.); (E.A.)
| | - Teodoro Bottiglieri
- Center of Metabolomics, Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX 75226, USA; (M.T.); (B.W.); (C.H.); (E.A.)
- Correspondence:
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Adams CD. Circulating Glutamine and Alzheimer's Disease: A Mendelian Randomization Study. Clin Interv Aging 2020; 15:185-193. [PMID: 32103921 PMCID: PMC7020919 DOI: 10.2147/cia.s239350] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/09/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Alzheimer's disease is a devastating neurodegenerative disorder. Its worldwide prevalence is over 24 million and is expected to double by 2040. Finding ways to prevent its cognitive decline is urgent. METHODS A two-sample Mendelian randomization study was performed instrumenting glutamine, which is abundant in blood, capable of crossing the blood-brain barrier, and involved in a metabolic cycle with glutamate in the brain. RESULTS The results reveal a protective effect of circulating glutamine against Alzheimer's disease (inverse-variance weighted method, odds ratio per 1-standard deviation increase in circulating glutamine = 0.83; 95% CI 0.71, 0.97; P = 0.02). CONCLUSION These findings lend credence to the emerging story supporting the modifiability of glutamine/glutamate metabolism for the prevention of cognitive decline. More circulating glutamine might mean that more substrate is available during times of stress, acting as a neuroprotectant. Modifications to exogenous glutamine may be worth exploring in future efforts to prevent and/or treat Alzheimer's disease.
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Skotte NH, Andersen JV, Santos A, Aldana BI, Willert CW, Nørremølle A, Waagepetersen HS, Nielsen ML. Integrative Characterization of the R6/2 Mouse Model of Huntington's Disease Reveals Dysfunctional Astrocyte Metabolism. Cell Rep 2019; 23:2211-2224. [PMID: 29768217 DOI: 10.1016/j.celrep.2018.04.052] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/23/2018] [Accepted: 04/12/2018] [Indexed: 01/05/2023] Open
Abstract
Huntington's disease is a fatal neurodegenerative disease, where dysfunction and loss of striatal and cortical neurons are central to the pathogenesis of the disease. Here, we integrated quantitative studies to investigate the underlying mechanisms behind HD pathology in a systems-wide manner. To this end, we used state-of-the-art mass spectrometry to establish a spatial brain proteome from late-stage R6/2 mice and compared this with wild-type littermates. We observed altered expression of proteins in pathways related to energy metabolism, synapse function, and neurotransmitter homeostasis. To support these findings, metabolic 13C labeling studies confirmed a compromised astrocytic metabolism and regulation of glutamate-GABA-glutamine cycling, resulting in impaired release of glutamine and GABA synthesis. In recent years, increasing attention has been focused on the role of astrocytes in HD, and our data support that therapeutic strategies to improve astrocytic glutamine homeostasis may help ameliorate symptoms in HD.
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Affiliation(s)
- Niels H Skotte
- Proteomics Program, The Novo Nordisk Foundation Centre for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alberto Santos
- Proteomics Program, The Novo Nordisk Foundation Centre for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cecilie W Willert
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Nørremølle
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael L Nielsen
- Proteomics Program, The Novo Nordisk Foundation Centre for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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Zhang M, Cheng X, Dang R, Zhang W, Zhang J, Yao Z. Lactate Deficit in an Alzheimer Disease Mouse Model: The Relationship With Neuronal Damage. J Neuropathol Exp Neurol 2019; 77:1163-1176. [PMID: 30383244 DOI: 10.1093/jnen/nly102] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/08/2018] [Indexed: 01/07/2023] Open
Abstract
Cerebral energy metabolism in Alzheimer disease (AD) has recently been given increasing attention. This study focuses on the alterations of cerebral lactate metabolism in the double-transgenic amyloid precursor protein/presenilin 1 (APP/PS1) mouse model of AD. Immunofluorescence staining and Western blotting analysis were used to identify the alterations of lactate content and lactate transporters (MCT1, MCT2, MCT4) in APP/PS1 mouse brains, which display amyloid beta plaques, reduced amounts of neurons and oligodendrocytes, and increased quantity of astrocytes. We found that lactate content and expressions of cerebral MCT1, MCT2, and MCT4 were decreased in APP/PS1 mice. In particular, lactate dehydrogenase A (LDHA) and B (LDHB) were reduced in neurons with increased ratios of LDHA and LDHB. This study suggests that the decreases of cerebral lactate content and lactate transporters may lead to the blockage of lactate transport from glia to neurons, resulting in neuronal lactate deficit. The increased ratio of neuronal LDHA and LDHB may represent a reaction of neurons to lactate deficit, although it cannot reverse the energy deficiency in neurons.
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Affiliation(s)
- Mao Zhang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiaofang Cheng
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Ruozhi Dang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Weiwei Zhang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jie Zhang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhongxiang Yao
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
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44
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Emmerzaal TL, Rodenburg RJ, Tanila H, Verweij V, Kiliaan AJ, Kozicz T. Age-Dependent Decrease of Mitochondrial Complex II Activity in a Familial Mouse Model for Alzheimer's Disease. J Alzheimers Dis 2019; 66:75-82. [PMID: 30248054 DOI: 10.3233/jad-180337] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative disorder for which the exact etiology is largely unknown. An increasingly recognized and investigated notion is the pathogenic role of mitochondrial dysfunction in AD. We assessed mitochondrial oxidative-phosphorylation (OXPHOS) enzyme activities in the APPswe/PS1ΔE9 mouse model from 4.5 to 14 months of age. We show an age-dependent decrease in mitochondrial complex-II activity starting at 9 months in APP/PS1 mice. Other enzymes of the OXPHOS do not show any alterations. Since amyloid-β (Aβ) plaques are already present from 4 months of age, mitochondrial dysfunction likely occurs downstream of Aβ pathology in this mouse model.
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Affiliation(s)
- Tim L Emmerzaal
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Richard J Rodenburg
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Vivienne Verweij
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Amanda J Kiliaan
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Tamas Kozicz
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
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Pan Y, Omori K, Ali I, Tachikawa M, Terasaki T, Brouwer KLR, Nicolazzo JA. Increased Expression of Renal Drug Transporters in a Mouse Model of Familial Alzheimer's Disease. J Pharm Sci 2019; 108:2484-2489. [PMID: 30825461 PMCID: PMC6888996 DOI: 10.1016/j.xphs.2019.02.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/03/2019] [Accepted: 02/19/2019] [Indexed: 01/18/2023]
Abstract
It is well established that the expression and function of drug transporters at the blood-brain barrier are altered in Alzheimer's disease (AD). However, we recently demonstrated in a mouse model of AD that the expression of key drug transporters and metabolizing enzymes was modified in peripheral organs, such as the small intestine and liver, suggesting that systemic drug absorption may be altered in AD. The purpose of this study was to determine whether the expression of drug transporters in the kidneys differed between 8- to 9-month-old wild-type mice and APPswe/PSEN1dE9 (APP/PS1) transgenic mice, a mouse model of familial AD, using a quantitative targeted absolute proteomics approach. The protein expression of the drug transporters-multidrug resistance-associated protein 2, organic anion transporter 3, and organic cation transporter 2-was upregulated 1.6-, 1.3-, and 1.4-fold, respectively, in kidneys from APP/PS1 mice relative to wild-type mice. These results suggest that in addition to modified oral absorption of certain drugs, it is possible that the renal excretion of drugs that are multidrug resistance-associated protein 2, organic anion transporter 3, and organic cation transporter 2 substrates could be altered in AD. These changes could affect the interpretation of studies conducted during drug development using this mouse model of AD and potentially impact dosage regimens of such drugs prescribed in this patient population.
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Affiliation(s)
- Yijun Pan
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Victoria 3052, Australia
| | - Kotaro Omori
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Izna Ali
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, 301 Pharmacy Lane, Chapel Hill, North Carolina 27599
| | - Masanori Tachikawa
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Tetsuya Terasaki
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Kim L R Brouwer
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, 301 Pharmacy Lane, Chapel Hill, North Carolina 27599
| | - Joseph A Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Victoria 3052, Australia.
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Andersen JV, Skotte NH, Aldana BI, Nørremølle A, Waagepetersen HS. Enhanced cerebral branched-chain amino acid metabolism in R6/2 mouse model of Huntington's disease. Cell Mol Life Sci 2019; 76:2449-2461. [PMID: 30830240 PMCID: PMC11105563 DOI: 10.1007/s00018-019-03051-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/23/2019] [Accepted: 02/19/2019] [Indexed: 01/01/2023]
Abstract
Huntington's disease (HD) is a hereditary and fatal disease causing profound neurodegeneration. Deficits in cerebral energy and neurotransmitter metabolism have been suggested to play a central role in the neuronal dysfunction and death associated with HD. The branched-chain amino acids (BCAAs), leucine, isoleucine and valine, are important for cerebral nitrogen homeostasis, neurotransmitter recycling and can be utilized as energy substrates in the tricarboxylic acid (TCA) cycle. Reduced levels of BCAAs in HD have been validated by several reports. However, it is still unknown how cerebral BCAA metabolism is regulated in HD. Here we investigate the metabolism of leucine and isoleucine in the R6/2 mouse model of HD. Acutely isolated cerebral cortical and striatal slices of control and R6/2 mice were incubated in media containing 15N- or 13C-labeled leucine or isoleucine and slice extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) to determine isotopic enrichment of derived metabolites. Elevated BCAA transamination was found from incubations with [15N]leucine and [15N]isoleucine, in both cerebral cortical and striatal slices of R6/2 mice compared to controls. Metabolism of [U-13C]leucine and [U-13C]isoleucine, entering oxidative metabolism as acetyl CoA, was maintained in R6/2 mice. However, metabolism of [U-13C]isoleucine, entering the TCA cycle as succinyl CoA, was elevated in both cerebral cortical and striatal slices of R6/2 mice, suggesting enhanced metabolic flux via this anaplerotic pathway. To support the metabolic studies, expression of enzymes in the BCAA metabolic pathway was assessed from a proteomic resource. Several enzymes related to BCAA metabolism were found to exhibit augmented expression in the R6/2 brain, particularly related to isoleucine metabolism, suggesting an increase in the BCAA metabolic machinery. Our results show that the capacity for cerebral BCAA metabolism, predominantly of isoleucine, is amplified in the R6/2 brain and indicates that perturbations in cerebral BCAA homeostasis could have functional consequences for HD pathology.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Niels H Skotte
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Anne Nørremølle
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
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Deletion of Neuronal GLT-1 in Mice Reveals Its Role in Synaptic Glutamate Homeostasis and Mitochondrial Function. J Neurosci 2019; 39:4847-4863. [PMID: 30926746 DOI: 10.1523/jneurosci.0894-18.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 02/07/2019] [Accepted: 03/10/2019] [Indexed: 01/19/2023] Open
Abstract
The glutamate transporter GLT-1 is highly expressed in astrocytes but also in neurons, primarily in axon terminals. We generated a conditional neuronal GLT-1 KO using synapsin 1-Cre (synGLT-1 KO) to elucidate the metabolic functions of GLT-1 expressed in neurons, here focusing on the cerebral cortex. Both synaptosomal uptake studies and electron microscopic immunocytochemistry demonstrated knockdown of GLT-1 in the cerebral cortex in the synGLT-1 KO mice. Aspartate content was significantly reduced in cerebral cortical extracts as well as synaptosomes from cerebral cortex of synGLT-1 KO compared with control littermates. 13C-Labeling of tricarboxylic acid cycle intermediates originating from metabolism of [U-13C]-glutamate was significantly reduced in synGLT-1 KO synaptosomes. The decreased aspartate content was due to diminished entry of glutamate into the tricarboxylic acid cycle. Pyruvate recycling, a pathway necessary for full glutamate oxidation, was also decreased. ATP production was significantly increased, despite unaltered oxygen consumption, in isolated mitochondria from the synGLT-1 KO. The density of mitochondria in axon terminals and perisynaptic astrocytes was increased in the synGLT-1 KO. Intramitochondrial cristae density of synGLT-1 KO mice was increased, suggesting increased mitochondrial efficiency, perhaps in compensation for reduced access to glutamate. SynGLT-1 KO synaptosomes exhibited an elevated oxygen consumption rate when stimulated with veratridine, despite a lower baseline oxygen consumption rate in the presence of glucose. GLT-1 expressed in neurons appears to be required to provide glutamate to synaptic mitochondria and is linked to neuronal energy metabolism and mitochondrial function.SIGNIFICANCE STATEMENT All synaptic transmitters need to be cleared from the extracellular space after release, and transporters are used to clear glutamate released from excitatory synapses. GLT-1 is the major glutamate transporter, and most GLT-1 is expressed in astrocytes. Only 5%-10% is expressed in neurons, primarily in axon terminals. The function of GLT-1 in axon terminals remains unknown. Here, we used a conditional KO approach to investigate the significance of the expression of GLT-1 in neurons. We found multiple abnormalities of mitochondrial function, suggesting impairment of glutamate utilization by synaptic mitochondria in the neuronal GLT-1 KO. These data suggest that GLT-1 expressed in axon terminals may be important in maintaining energy metabolism and biosynthetic activities mediated by presynaptic mitochondria.
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48
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Aldana BI. Microglia-Specific Metabolic Changes in Neurodegeneration. J Mol Biol 2019; 431:1830-1842. [PMID: 30878483 DOI: 10.1016/j.jmb.2019.03.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/22/2019] [Accepted: 03/05/2019] [Indexed: 02/06/2023]
Abstract
The high energetic demand of the brain deems this organ rather sensitive to changes in energy supply. Therefore, even minor alterations in energy metabolism may underlie detrimental disturbances in brain function, contributing to the generation and progression of neurodegenerative diseases. Considerable evidence supports the key role of deficits in cerebral energy metabolism, particularly hypometabolism of glucose and mitochondrial dysfunction, in the pathophysiology of brain disorders. Major breakthroughs in the field of bioenergetics and neurodegeneration have been achieved through the use of in vitro and in vivo models of disease as well as sophisticated neuroimaging techniques in patients, yet these have been mainly focused on neuron and astrocyte function. Remarkably, the subcellular metabolic mechanisms linked to neurodegeneration that operate in other crucial brain cell types such as microglia have remain obscured, although they are beginning to be unraveled. Microglia, the brain-resident immune sentinels, perform a diverse range of functions that require a high-energy expenditure, namely, their role in brain development, maintenance of the neural environment, response to injury and infection, and activation of repair programs. Interestingly, another key mechanism underlying several neurodegenerative diseases is neuroinflammation, which can be associated with chronic microglia activation. Considering that many brain disorders are accompanied by changes in brain energy metabolism and sustained inflammation, and that energy metabolism has a strong influence on the inflammatory responses of microglia, the emerging significance of microglial energy metabolism in neurodegeneration is highlighted in this review.
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Affiliation(s)
- Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
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Chen L, Zhou L, Yu P, Fang F, Jiang L, Fei J, Xiao H, Wang J. Methamphetamine exposure upregulates the amyloid precursor protein and hyperphosphorylated tau expression: The roles of insulin signaling in SH-SY5Y cell line. J Toxicol Sci 2019; 44:493-503. [PMID: 31270305 DOI: 10.2131/jts.44.493] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Lingling Chen
- Children’s Hospital of Nanjing Medical University, China
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Li Zhou
- Children’s Hospital of Nanjing Medical University, China
| | - Pengfei Yu
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Fangfang Fang
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
- Community Health Service Center of Rong Xiang Street, China
| | - Lei Jiang
- Department of Emergency Medicine, the First Affiliated Hospital of Nanjing Medical University, China
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Jian Fei
- Children’s Hospital of Nanjing Medical University, China
| | - Hang Xiao
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Jun Wang
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
- China International Cooperation Center for Environment and Human Health, China
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50
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Hohnholt MC, Andersen VH, Andersen JV, Christensen SK, Karaca M, Maechler P, Waagepetersen HS. Glutamate dehydrogenase is essential to sustain neuronal oxidative energy metabolism during stimulation. J Cereb Blood Flow Metab 2018; 38. [PMID: 28621566 PMCID: PMC6168903 DOI: 10.1177/0271678x17714680] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The enzyme glutamate dehydrogenase (GDH; Glud1) catalyzes the (reversible) oxidative deamination of glutamate to α-ketoglutarate accompanied by a reduction of NAD+ to NADH. GDH connects amino acid, carbohydrate, neurotransmitter and oxidative energy metabolism. Glutamine is a neurotransmitter precursor used by neurons to sustain the pool of glutamate, but glutamine is also vividly oxidized for support of energy metabolism. This study investigates the role of GDH in neuronal metabolism by employing the Cns- Glud1-/- mouse, lacking GDH in the brain (GDH KO) and metabolic mapping using 13C-labelled glutamine and glucose. We observed a severely reduced oxidative glutamine metabolism during glucose deprivation in synaptosomes and cultured neurons not expressing GDH. In contrast, in the presence of glucose, glutamine metabolism was not affected by the lack of GDH expression. Respiration fuelled by glutamate was significantly lower in brain mitochondria from GDH KO mice and synaptosomes were not able to increase their respiration upon an elevated energy demand. The role of GDH for metabolism of glutamine and the respiratory capacity underscore the importance of GDH for neurons particularly during an elevated energy demand, and it may reflect the large allosteric activation of GDH by ADP.
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Affiliation(s)
- Michaela C Hohnholt
- 1 Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Vibe H Andersen
- 1 Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Jens V Andersen
- 1 Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Sofie K Christensen
- 1 Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Melis Karaca
- 2 Department of Cell Physiology and Metabolism, CMU, University of Geneva, Geneva, Switzerland
| | - Pierre Maechler
- 2 Department of Cell Physiology and Metabolism, CMU, University of Geneva, Geneva, Switzerland
| | - Helle S Waagepetersen
- 1 Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
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