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Ketogenic Diet Treatment of Defects in the Mitochondrial Malate Aspartate Shuttle and Pyruvate Carrier. Nutrients 2022; 14:nu14173605. [PMID: 36079864 PMCID: PMC9460686 DOI: 10.3390/nu14173605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/10/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022] Open
Abstract
The mitochondrial malate aspartate shuttle system (MAS) maintains the cytosolic NAD+/NADH redox balance, thereby sustaining cytosolic redox-dependent pathways, such as glycolysis and serine biosynthesis. Human disease has been associated with defects in four MAS-proteins (encoded by MDH1, MDH2, GOT2, SLC25A12) sharing a neurological/epileptic phenotype, as well as citrin deficiency (SLC25A13) with a complex hepatopathic-neuropsychiatric phenotype. Ketogenic diets (KD) are high-fat/low-carbohydrate diets, which decrease glycolysis thus bypassing the mentioned defects. The same holds for mitochondrial pyruvate carrier (MPC) 1 deficiency, which also presents neurological deficits. We here describe 40 (18 previously unreported) subjects with MAS-/MPC1-defects (32 neurological phenotypes, eight citrin deficiency), describe and discuss their phenotypes and genotypes (presenting 12 novel variants), and the efficacy of KD. Of 13 MAS/MPC1-individuals with a neurological phenotype treated with KD, 11 experienced benefits—mainly a striking effect against seizures. Two individuals with citrin deficiency deceased before the correct diagnosis was established, presumably due to high-carbohydrate treatment. Six citrin-deficient individuals received a carbohydrate-restricted/fat-enriched diet and showed normalisation of laboratory values/hepatopathy as well as age-adequate thriving. We conclude that patients with MAS-/MPC1-defects are amenable to dietary intervention and that early (genetic) diagnosis is key for initiation of proper treatment and can even be lifesaving.
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Bheemanapally K, Napit PR, Ibrahim MMH, Briski KP. UHPLC-electrospray ionization-mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content. Sci Rep 2021; 11:16079. [PMID: 34373537 PMCID: PMC8352916 DOI: 10.1038/s41598-021-95646-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Astrocyte glycogen, the primary energy reserve in brain, undergoes continuous remodeling by glucose passage through the glycogen shunt prior to conversion to the oxidizable energy fuel L-lactate. Glucogenic amino acids (GAAs) are a potential non-glucose energy source during neuro-metabolic instability. Current research investigated whether diminished glycogen metabolism affects GAA homeostasis in astrocyte and/or nerve cell compartments. The glycogen phosphorylase (GP) inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) was injected into the ventromedial hypothalamic nucleus (VMN), a key metabolic-sensing structure, before vehicle or L-lactate infusion. Pure VMN astrocyte and metabolic-sensory neuron samples were obtained by combinatory immunocytochemistry/laser-catapult-microdissection for UHPLC-electrospray ionization-mass spectrometry (LC-ESI-MS) GAA analysis. DAB inhibition of VMN astrocyte aspartate and glutamine (Gln) levels was prevented or exacerbated, respectively, by lactate. VMN gluco-stimulatory nitric oxide (NO; neuronal nitric oxide synthase-immunoreactive (ir)-positive) and gluco-inhibitory γ-aminobutyric acid (GABA; glutamate decarboxylase65/67-ir-positive) neurons exhibited lactate-reversible asparate and glutamate augmentation by DAB, but dissimilar Gln responses to DAB. GP inhibition elevated NO and GABA nerve cell GABA content, but diminished astrocyte GABA; these responses were averted by lactate in neuron, but not astrocyte samples. Outcomes provide proof-of-principle of requisite LC-ESI-MS sensitivity for GAA measurement in specific brain cell populations. Results document divergent effects of decreased VMN glycogen breakdown on astrocyte versus neuron GAAs excepting Gln. Lactate-reversible DAB up-regulation of metabolic-sensory neuron GABA signaling may reflect compensatory nerve cell energy stabilization upon decline in astrocyte-derived metabolic fuel.
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Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Prabhat R Napit
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA.
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Zhou Y, Xie Z, Zhang Z, Yang J, Chen M, Chen F, Ma Y, Chen C, Peng Q, Zou L, Gao J, Xu Y, Kuang Y, Zhu M, You D, Yu J, Wang K. Plasma metabolites changes in male heroin addicts during acute and protracted withdrawal. Aging (Albany NY) 2021; 13:18669-18688. [PMID: 34282053 PMCID: PMC8351709 DOI: 10.18632/aging.203311] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/25/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND Heroin addiction and withdrawal have been associated with an increased risk for infectious diseases and psychological complications. However, the changes of metabolites in heroin addicts during withdrawal remain largely unknown. METHODS A total of 50 participants including 20 heroin addicts with acute abstinence stage, 15 with protracted abstinence stage and 15 healthy controls, were recruited. We performed metabolic profiling of plasma samples based on ultraperformance liquid chromatography coupled to tandem mass spectrometry to explore the potential biomarkers and mechanisms of heroin withdrawal. RESULTS Among the metabolites analyzed, omega-6 polyunsaturated fatty acids (linoleic acid, dihomo-gamma-linolenic acid, arachidonic acid, n-6 docosapentaenoic acid), omega-3 polyunsaturated fatty acids (docosahexaenoic acid, docosapentaenoic acid), aromatic amino acids (phenylalanine, tyrosine, tryptophan), and intermediates of the tricarboxylic acid cycle (oxoglutaric acid, isocitric acid) were significantly reduced during acute heroin withdrawal. Although majority of the metabolite changes could recover after months of withdrawal, the levels of alpha-aminobutyric acid, alloisoleucine, ketoleucine, and oxalic acid do not recover. CONCLUSIONS In conclusion, the plasma metabolites undergo tremendous changes during heroin withdrawal. Through metabolomic analysis, we have identified links between a framework of metabolic perturbations and withdrawal stages in heroin addicts.
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Affiliation(s)
- Yong Zhou
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Zhenrong Xie
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Zunyue Zhang
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Jiqing Yang
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Minghui Chen
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Medical School, Kunming University of Science and Technology, Kunming 650032, Yunnan, China
| | - Fengrong Chen
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Yuru Ma
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Cheng Chen
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Yunnan Institute of Digestive Disease, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Qingyan Peng
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Lei Zou
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Jianyuan Gao
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Yu Xu
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Yunnan Institute of Digestive Disease, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Yiqun Kuang
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Mei Zhu
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Dingyun You
- School of Public Health, Kunming Medical University, Kunming 650032, Yunnan, China
| | - Juehua Yu
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Centre for Experimental Studies and Research, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Kunhua Wang
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China.,Yunnan University, Kunming 650032, Yunnan, China
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Garegrat R, Patnaik S, Suryawanshi P, Datar C. Focal congenital hyperinsulinism resulting from biallelic loss of function of KCNJ11 gene. BMJ Case Rep 2021; 14:14/3/e240218. [PMID: 33762279 PMCID: PMC7993335 DOI: 10.1136/bcr-2020-240218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Congenital hyperinsulinism (CHI) characterised by inappropriate secretion of insulin despite low blood glucose can result in irreversible brain damage if not promptly treated. The most common genetic cause of hyperinsulinism is the pathogenic variants in ABCC8 and KCNJ11, causing dysregulated insulin secretion. Rapid testing is crucial for all patients because finding a mutation significantly impacts this condition's clinical management. We report a rare case of focal CHI after a homozygous KCNJ11 mutation who underwent a selective lesionectomy and required octreotide for euglycaemia.
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Affiliation(s)
- Reema Garegrat
- Department of Neonatology, Bharati Hospital and Research Centre, Pune, Maharashtra, India
| | - Suprabha Patnaik
- Department of Neonatology, Bharati Hospital and Research Centre, Pune, Maharashtra, India
| | | | - Chaitanya Datar
- Department of Neonatology, Bharati Hospital and Research Centre, Pune, Maharashtra, India
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Bheemanapally K, Ibrahim MMH, Briski KP. HPLC-electrospray ionization-mass spectrometry optimization by high-performance design of experiments for astrocyte glutamine measurement. JOURNAL OF MASS SPECTROMETRY : JMS 2021; 56:e4680. [PMID: 33462970 PMCID: PMC7874509 DOI: 10.1002/jms.4680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/01/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
The amino acid glutamine (Gln) is a likely source of energy in the brain during neuroglucopenia. Effects of glucose deficiency on astrocyte Gln homeostasis remain unclear, as analytical tools of requisite sensitivity for quantification of intracellular levels of this molecule are not currently available. Here, a primary hypothalamic astrocyte culture model was used in conjunction with design of experiments (DOE)-refined high-performance liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) methodology to investigate the hypothesis that glucoprivation alters astrocyte Gln content in a sex-specific manner. Critical mass spectrometric parameters for Gln derivative chromatographic response were identified by comparing the performance of central composite design, Box-Behnken design, and Optimal Design (OD)-A, -D, -I, -Distance, and -Modified Distance DOE models. The outcomes showed that the OD-A-generated response was superior relative to other design outcomes. Forecasted surface plot critical mass spectrometric parameters were maximized by OD-A, OD-Distance, and OD-Modified Distance designs. OD-A produced a high-performance method that yielded experimental run and forecasted surface plot maximal responses. Optimized mass spectrometric analysis of male versus female astrocyte Gln content provides novel evidence that glucoprivation significantly depletes this amino acid in female, but not in male, and that this sex-specific response may involve differential sensitivity to estrogen receptor signaling. This technological advance will facilitate efforts to ascertain how distinctive physiological and pathophysiological stimuli impact astrocyte Gln metabolism in each sex.
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Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
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Kosenko E, Tikhonova L, Alilova G, Montoliu C. A Look into Liver Mitochondrial Dysfunction as a Hallmark in Progression of Brain Energy Crisis and Development of Neurologic Symptoms in Hepatic Encephalopathy. J Clin Med 2020; 9:E2259. [PMID: 32708652 PMCID: PMC7408643 DOI: 10.3390/jcm9072259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/18/2020] [Accepted: 07/13/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The relationship between liver disease and neuropathology in hepatic encephalopathy is well known, but the genesis of encephalopathy in liver failure is yet to be elucidated. Conceptually, the main cause of hepatic encephalopathy is the accumulation of brain ammonia due to impaired liver detoxification function or occurrence of portosystemic shunt. Yet, as well as taking up toxic ammonia, the liver also produces vital metabolites that ensure normal cerebral function. Given this, for insight into how perturbations in the metabolic capacity of the liver may be related to brain pathology, it is crucial to understand the extent of ammonia-related changes in the hepatic metabolism that provides respiratory fuel for the brain, a deficiency of which can give rise to encephalopathy. METHODS Hepatic encephalopathy was induced in starved rats by injection of ammonium acetate. Ammonia-induced toxicity was evaluated by plasma and freeze-clamped liver and brain energy metabolites, and mitochondrial, cytoplasmic, and microsomal gluconeogenic enzymes, including mitochondrial ketogenic enzymes. Parameters of oxidative phosphorylation were recorded polarographically with a Clark-type electrode, while other measures were determined with standard fluorometric enzymatic methods. RESULTS Progressive impairment of liver mitochondrial respiration in the initial stage of ammonia-induced hepatotoxicity and the subsequent energy crisis due to decreased ATP synthesis lead to cessation of gluconeogenesis and ketogenesis. Reduction in glucose and ketone body supply to the brain is a terminal event in liver toxicity, preceding the development of coma. CONCLUSIONS Our study provides a framework to further explore the relationship between hepatic dysfunction and progression of brain energy crisis in hepatic encephalopathy.
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Affiliation(s)
- Elena Kosenko
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia; (L.T.); (G.A.)
| | - Lyudmila Tikhonova
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia; (L.T.); (G.A.)
| | - Gubidat Alilova
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia; (L.T.); (G.A.)
| | - Carmina Montoliu
- Hospital Clinico Research Foundation, INCLIVA Health Research Institute, 46010 Valencia, Spain;
- Pathology Department, Faculty of Medicine, University of Valencia, 46010 Valencia, Spain
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7
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Bheemanapally K, Ibrahim MMH, Briski KP. High performance liquid chromatography-electrospray ionization mass spectrometric (LC-ESI-MS) methodology for analysis of amino acid energy substrates in microwave-fixed microdissected brain tissue. J Pharm Biomed Anal 2020; 184:113123. [PMID: 32120188 DOI: 10.1016/j.jpba.2020.113123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/15/2022]
Abstract
Hypoglycemia deprives the brain of its primary energy source glucose. Reductions in whole-brain amino acid energy substrate levels suggest that these non-glucose fuels may be metabolized during glucose shortage. Recurring hypoglycemia can cause mal-adaptive impairment of glucose counter-regulation; yet, it is unclear if amplified reliance upon alternative metabolic substrates impedes detection of continuing neuro-glucopenia. This research aimed to develop high-sensitivity UHPLC-electrospray ionization mass spectrometric (LC-ESI-MS) methodology, for complementary use with high-neuroanatomical resolution microdissection tools, for measurement of glucogenic amino acid, e.g. glutamine (Gln), glutamate (Glu), and aspartate (Asp) content in the characterized glucose-sensing ventromedial hypothalamic nucleus (VMN) during acute versus chronic hypoglycemia. Results show that VMN tissue Gln, Glu, and Asp levels were significantly decreased during a single hypoglycemic episode, and that Gln and Asp measures were correspondingly normalized or further diminished during renewed hypoglycemia. Results provide proof-of-principle that LC-ESI-MS has requisite sensitivity for amino acid energy substrate quantification in distinctive brain gluco-regulatory structures under conditions of eu- versus hypoglycemia. This novel combinatory methodology will support ongoing efforts to determine how amino acid energy yield may impact VMN metabolic sensory function during persistent hypoglycemia.
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Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA, 71201, United States(1)
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA, 71201, United States(1)
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA, 71201, United States(1).
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8
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Briski KP, Mandal SK, Bheemanapally K, Ibrahim MMH. Effects of acute versus recurrent insulin-induced hypoglycemia on ventromedial hypothalamic nucleus metabolic-sensory neuron AMPK activity: Impact of alpha 1-adrenergic receptor signaling. Brain Res Bull 2020; 157:41-50. [PMID: 31981674 DOI: 10.1016/j.brainresbull.2020.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/15/2019] [Accepted: 01/17/2020] [Indexed: 12/24/2022]
Abstract
Mechanisms that underlie metabolic sensor acclimation to recurring insulin-induced hypoglycemia (RIIH) are unclear. Norepinephrine (NE) regulates ventromedial hypothalamic nucleus (VMN) gluco-stimulatory nitric oxide (NO) and gluco-inhibitory γ-aminobutryic acid (GABA) neuron signaling. Current research addressed the hypothesis that during RIIH, NE suppresses 5'-AMP-activated protein kinase (AMPK) reactivity in both populations and impedes counter-regulation. The brain is postulated to utilize non-glucose substrates, e.g. amino acids glutamine (Gln), glutamate (Glu), and aspartate (Asp), to produce energy during hypoglycemia. A correlated aim investigated whether NE controls pyruvate recycling pathway marker protein (glutaminase, GLT; malic enzyme, ME-1) expression in either metabolic-sensory cell population. Male rats were injected subcutaneously with vehicle or insulin on days 1-3, then pretreated on day 4 by intracerebroventricular delivery of the alpha1-adrenergic receptor (α1-AR) reverse-agonist prazocin (PRZ) or vehicle before final insulin therapy. PRZ prevented acute hypoglycemic augmentation of AMPK activation in each cell group. Antecedent hypoglycemic repression of sensor activity was reversed by PRZ in GABA neurons. During RIIH, nitrergic neurons exhibited α1-AR - dependent up-regulated GLT and α2-AR profiles, while GABA cells showed down-regulated α1-AR. LC-ESI-MS analysis documented a decline in VMN Glu, Gln, and Asp concentrations during acute hypoglycemia, and habituation of the former two profiles to RIIH. PRZ attenuated glucagon and corticosterone secretion during acute hypoglycemia, but reversed decrements in output of both hormones during RIIH. Results implicate adjustments in impact of α1-AR signaling in repressed VMN metabolic-sensory AMPK activation and counter-regulatory dysfunction during RIIH. Antecedent hypoglycemia may up-regulate NO neuron energy yield via α1-AR - mediated up-regulated pyruvate recycling.
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Affiliation(s)
- Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71201, United States.
| | - Santosh K Mandal
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71201, United States
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71201, United States
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71201, United States
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9
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Sergi D, Renaud J, Simola N, Martinoli MG. Diabetes, a Contemporary Risk for Parkinson's Disease: Epidemiological and Cellular Evidences. Front Aging Neurosci 2019; 11:302. [PMID: 31787891 PMCID: PMC6856011 DOI: 10.3389/fnagi.2019.00302] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022] Open
Abstract
Diabetes mellitus (DM), a group of diseases characterized by defective glucose metabolism, is the most widespread metabolic disorder affecting over 400 million adults worldwide. This pathological condition has been implicated in the pathogenesis of a number of central encephalopathies and peripheral neuropathies. In further support of this notion, recent epidemiological evidence suggests a link between DM and Parkinson’s disease (PD), with hyperglycemia emerging as one of the culprits in neurodegeneration involving the nigrostriatal pathway, the neuroanatomical substrate of the motor symptoms affecting parkinsonian patients. Indeed, dopaminergic neurons located in the mesencephalic substantia nigra appear to be particularly vulnerable to oxidative stress and degeneration, likely because of their intrinsic susceptibility to mitochondrial dysfunction, which may represent a direct consequence of hyperglycemia and hyperglycemia-induced oxidative stress. Other pathological pathways induced by increased intracellular glucose levels, including the polyol and the hexosamine pathway as well as the formation of advanced glycation end-products, may all play a pivotal role in mediating the detrimental effects of hyperglycemia on nigral dopaminergic neurons. In this review article, we will examine the epidemiological as well as the molecular and cellular clues supporting the potential susceptibility of nigrostriatal dopaminergic neurons to hyperglycemia.
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Affiliation(s)
- Domenico Sergi
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, SA, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Justine Renaud
- Cellular Neurobiology, Department of Medical Biology, Université du Québec, Trois-Rivières, QC, Canada
| | - Nicola Simola
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.,National Institute for Neuroscience (INN), University of Cagliari, Cagliari, Italy
| | - Maria-Grazia Martinoli
- Cellular Neurobiology, Department of Medical Biology, Université du Québec, Trois-Rivières, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval and CHU Research Center, Québec, QC, Canada
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Richter J, Rabe D, Duysen K, Melchert UH, Oltmanns KM. Lactate infusion increases brain energy content during euglycemia but not hypoglycemia in healthy men. NMR IN BIOMEDICINE 2019; 32:e4167. [PMID: 31468650 DOI: 10.1002/nbm.4167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 07/04/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
A special characteristic of the brain is the usage of lactate as alternative fuel instead of glucose to preserve its energy homeostasis. This physiological function is valid for sufficient cerebral glucose supply, as well as presumably during hypoglycemia, given that exogenous lactate infusion suppresses hormonal counterregulation. However, it is not yet clarified whether this effect is mediated by the use of lactate as an alternative cerebral energy substrate or any other mechanism. We hypothesized that under conditions of limited access to glucose (ie, during experimental hypoglycemia) lactate infusion would prevent hypoglycemia-induced neuroenergetic deficits in a neuroprotective way. In a randomized, double-blind, crossover study, lactate vs placebo infusion was compared during hyperinsulinemic-hypoglycemic clamps in 16 healthy young men. We measured the cerebral high-energy phosphate content - ie, adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate (Pi) levels - by 31 P-magnetic resonance spectroscopy as well as the neuroendocrine stress response. During euglycemia, lactate infusion increased ATP/Pi as well as PCr/Pi ratios compared with baseline values and placebo infusion. During hypoglycemia, there were no differences between the lactate and the placebo condition in both ratios. Hormonal counterregulation was significantly diminished upon lactate infusion. Our data demonstrate an elevated cerebral high-energy phosphate content upon lactate infusion during euglycemia, whereas there was no such effect during experimental hypoglycemia. Nevertheless, lactate infusion suppressed hypoglycemic hormonal counterregulation. Lactate thus adds to cerebral energy provision during euglycemia and may contribute to an increase in ATP reserves, which in turn protects the brain against neuroglucopenia under recurrent hypopglycemic conditions, eg, in diabetic patients.
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Affiliation(s)
- Juliane Richter
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Doerte Rabe
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kai Duysen
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Uwe H Melchert
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kerstin M Oltmanns
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
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Uddin MM, Mahmood ASMH, Ibrahim MMH, Briski KP. Sex-dimorphic estrogen receptor regulation of ventromedial hypothalamic nucleus glucoregulatory neuron adrenergic receptor expression in hypoglycemic male and female rats. Brain Res 2019; 1720:146311. [PMID: 31265816 PMCID: PMC6702034 DOI: 10.1016/j.brainres.2019.146311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/15/2019] [Accepted: 06/27/2019] [Indexed: 10/26/2022]
Abstract
The ventromedial hypothalamic nucleus (VMN) is a vital component of the neural circuitry that regulates glucostasis. Norepinephrine (NE) controls VMN gluco-inhibitory γ-aminobutyric acid (GABA) and gluco-stimulatory nitric oxide (NO) transmission. Sex-specific insulin-induced hypoglycemic (IIH) patterns of VMN GABA signaling are estrogen receptor-alpha (ERα)- and -beta (ERβ)-dependent. Current research utilized combinatory immunocytochemistry, laser-microdissection, and Western blot techniques in a pharmacological approach to address the hypothesis that ERα and/or -β mediate sex-dimorphic VMN GABAergic and/or nitrergic nerve cell receptivity to NE and estradiol during IIH. The impact of these ER on expression of the pyruvate recycling pathway marker proteins glutaminase (GLS) and malic enzyme-1 (ME-1) was also examined. Both VMN neuron populations express ERα, ERβ, and G protein-coupled estrogen receptor-1 (GPER), along with alpha1, alpha2, and beta1 adrenergic receptor (AR) proteins. NO neurons exhibited ERα/β-dependent (beta1 AR, GPER) and -independent (alpha1 AR) sex differences in receptor protein responses to hypoglycemia. Similarly, sex-dimorphic effects of IIH on alpha1 AR, alpha2 AR, and ERα profiles in GABA neurons involve ERα/β. These ERs also underlie divergent adjustments in gluco-regulatory nerve cell GLS and ME-1 protein expression in hypoglycemic males and females. Sex-specific nitrergic and GABAergic nerve cell sensitivity to NE and E, respectively, during IIH may contribute to sex-contingent patterns of neurotransmitter signaling.
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Affiliation(s)
- M Main Uddin
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - A S M Hasan Mahmood
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States.
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Xin W, Mironova YA, Shen H, Marino RAM, Waisman A, Lamers WH, Bergles DE, Bonci A. Oligodendrocytes Support Neuronal Glutamatergic Transmission via Expression of Glutamine Synthetase. Cell Rep 2019; 27:2262-2271.e5. [PMID: 31116973 PMCID: PMC6544175 DOI: 10.1016/j.celrep.2019.04.094] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/16/2019] [Accepted: 04/22/2019] [Indexed: 11/30/2022] Open
Abstract
Glutamate has been implicated in a wide range of brain pathologies and is thought to be metabolized via the astrocyte-specific enzyme glutamine synthetase (GS). We show here that oligodendrocytes, the myelinating glia of the central nervous system, also express high levels of GS in caudal regions like the midbrain and the spinal cord. Selective removal of oligodendrocyte GS in mice led to reduced brain glutamate and glutamine levels and impaired glutamatergic synaptic transmission without disrupting myelination. Furthermore, animals lacking oligodendrocyte GS displayed deficits in cocaine-induced locomotor sensitization, a behavior that is dependent on glutamatergic signaling in the midbrain. Thus, oligodendrocytes support glutamatergic transmission through the actions of GS and may represent a therapeutic target for pathological conditions related to brain glutamate dysregulation.
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Affiliation(s)
- Wendy Xin
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Yevgeniya A Mironova
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hui Shen
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA
| | - Rosa A M Marino
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA
| | - Ari Waisman
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University, 55128 Mainz, Germany
| | - Wouter H Lamers
- Academic Medical Center, Tytgat Institute for Liver and Intestinal Research, 1105 BK Amsterdam, the Netherlands
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Antonello Bonci
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neuroscience, Georgetown University Medical Center, School of Medicine, Washington, DC 20007, USA; Department of Psychiatry, University of Maryland, School of Medicine, Baltimore, MD 21205, USA.
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13
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Nistor M, Schmidt M, Graul I, Rakers F, Schiffner R. A Systematic Review of Neuroprotective Strategies in the Management of Hypoglycemia. Int J Mol Sci 2019; 20:ijms20030550. [PMID: 30696060 PMCID: PMC6386855 DOI: 10.3390/ijms20030550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 02/07/2023] Open
Abstract
Severe hypogylcemia has been found to induce cerebral damage. While a number of illnesses can lead to hypoglycemic episodes, antidiabetic medications prescribed for glycemic control are a common cause. Considering the rising prevalence of diabetes mellitus in the population, we investigated neuroprotective strategies during hypoglycemia in the form of a systematic review in adherence to the PRISMA statement. A review protocol was registered in the PROSPERO database. A systematic literature search of PubMed, Web of Science, and CENTRAL was performed in September 2018. Based on a predefined inclusion protocol, results were screened and evaluated by two researchers. Both animal experiments and human studies were included, and their risk of bias was assessed with SYRCLE’s and the Cochrane risk of bias tools, respectively. Of a total of 16,230 results, 145 were assessed in full-text form: 27 articles adhered to the inclusion criteria and were qualitatively analyzed. The retrieved neuroprotective strategies could be categorized into three subsets: (1) Energy substitution, (2) hypoglycemia unawareness, and (3) other neuroprotective strategies. While on a study level, the individual results appeared promising, more research is required to investigate not only specific neuroprotective strategies against hypoglycemic cerebral damage, but also its underlying pathophysiological mechanisms.
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Affiliation(s)
- Marius Nistor
- Department of Neurology, Jena University Hospital - Friedrich Schiller University, Jena 07747, Germany.
| | - Martin Schmidt
- Institute for Biochemistry II, Jena University Hospital - Friedrich Schiller University, Jena 07743, Germany.
| | - Isabel Graul
- Orthopedic Department, Jena University Hospital - Friedrich Schiller University, Campus Eisenberg, Klosterlausnitzer Straße 81, Eisenberg 07607, Germany.
| | - Florian Rakers
- Department of Neurology, Jena University Hospital - Friedrich Schiller University, Jena 07747, Germany.
| | - René Schiffner
- Department of Neurology, Jena University Hospital - Friedrich Schiller University, Jena 07747, Germany.
- Orthopedic Department, Jena University Hospital - Friedrich Schiller University, Campus Eisenberg, Klosterlausnitzer Straße 81, Eisenberg 07607, Germany.
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Yanuck SF. Microglial Phagocytosis of Neurons: Diminishing Neuronal Loss in Traumatic, Infectious, Inflammatory, and Autoimmune CNS Disorders. Front Psychiatry 2019; 10:712. [PMID: 31632307 PMCID: PMC6786049 DOI: 10.3389/fpsyt.2019.00712] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/05/2019] [Indexed: 01/08/2023] Open
Abstract
Errors in neuron-microglial interaction are known to lead to microglial phagocytosis of live neurons and excessive neuronal loss, potentially yielding poorer clinical outcomes. Factors that affect neuron-microglial interaction have the potential to influence the error rate. Clinical comorbidities that unfavorably impact neuron-microglial interaction may promote a higher rate of neuronal loss, to the detriment of patient outcome. This paper proposes that many common, clinically modifiable comorbidities have a common thread, in that they all influence neuron-microglial interactions. Comorbidities like traumatic brain injury, infection, stress, neuroinflammation, loss of neuronal metabolic integrity, poor growth factor status, and other factors, all have the potential to alter communication between neurons and microglia. When this occurs, microglial phagocytosis of live neurons can increase. In addition, microglia can shift into a morphological form in which they express major histocompatibility complex II (MHC-II), allowing them to function as antigen presenting cells that present neuronal debris as antigen to invading T cells. This can increase risk for the development of CNS autoimmunity, or can exacerbate existing CNS autoimmunity. The detrimental influence of these comorbidities has the potential to contribute to the mosaic of factors that determine patient outcome in some CNS pathologies that have neuropsychiatric involvement, including TBI and CNS disorders with autoimmune components, where excessive neuronal loss can yield poorer clinical outcomes. Recognition of the impact of these comorbidities may contribute to an understanding of the common clinical observation that many seemingly disparate factors contribute to the overall picture of case management and clinical outcome in these complex disorders. In a clinical setting, knowing how these comorbidities can influence neuron-microglial interaction can help focus surveillance and care on a broader group of potential therapeutic targets. Accordingly, an interest in the mechanisms underlying the influence of these factors on neuron-microglial interactions is appropriate. Neuron-microglial interaction is reviewed, and the various mechanisms by which these potential comorbidities influence neuro-microglial interaction are described.
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Affiliation(s)
- Samuel F Yanuck
- Program on Integrative Medicine, Department of Physical Medicine and Rehabilitation, University of North Carolina School of Medicine, Chapel Hill, NC, United States
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15
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Hasan Mahmood ASM, Uddin MM, Ibrahim MMH, Mandal SK, Alhamami HN, Briski KP. Sex differences in forebrain estrogen receptor regulation of hypoglycemic patterns of counter-regulatory hormone secretion and ventromedial hypothalamic nucleus glucoregulatory neurotransmitter and astrocyte glycogen metabolic enzyme expression. Neuropeptides 2018; 72:65-74. [PMID: 30396594 PMCID: PMC6293983 DOI: 10.1016/j.npep.2018.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/24/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022]
Abstract
The female ventromedial hypothalamic nucleus (VMN) is a focal substrate for estradiol (E) regulation of energy balance, feeding, and body weight, but how E shapes VMN gluco-regulatory signaling in each sex is unclear. This study investigated the hypothesis that estrogen receptor-alpha (ERα) and/or -beta (ERβ) control VMN signals that inhibit [γ-aminobutyric acid] or stimulate [nitric oxide, steroidogenic factor-1 (SF-1)] counter-regulation in a sex-dependent manner. VMN nitrergic neurons monitor astrocyte fuel provision; here, we examined how these ER regulate astrocyte glycogen metabolic enzyme, monocarboxylate transporter, and adrenoreceptor protein responses to insulin-induced hypoglycemia (IIH) in each sex. Testes-intact male and E-replaced ovariectomized female rats were pretreated by intracerebroventricular ERα antagonist (MPP) or ERβ antagonist (PHTPP) administration before IIH. Data implicate both ER in hypoglycemic inhibition of neuronal nitric oxide synthase protein in each sex and up-regulation of glutamate decarboxylase65/67 and SF-1 expression in females. ERα and -β enhance astrocyte AMPK and glycogen synthase expression and inhibit glycogen phosphorylase in hypoglycemic females, while ERβ suppresses the same proteins in males. Differential VMN astrocyte protein responses to IIH may partially reflect ERα and -β augmentation of ERβ and down-regulation of alpha1, alpha2, and beta1 adrenoreceptor proteins in females, versus ERβ repression of GPER and alpha2 adrenoreceptor profiles in males. MPP or PHTPP pretreatment blunted counter-regulatory hormone secretion in hypoglycemic males only, suggesting that in males one or more VMN neurotransmitters exhibiting sensitivity to forebrain ER may passively regulate this endocrine outflow, whereas female forebrain ERα and -β are apparently uninvolved in these contra-regulatory responses.
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Affiliation(s)
- A S M Hasan Mahmood
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA
| | - M M Uddin
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA
| | - M M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA
| | - S K Mandal
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA
| | - H N Alhamami
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA
| | - K P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA.
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Ludwig A, Enke S, Heindorf J, Empting S, Meissner T, Mohnike K. Formal Neurocognitive Testing in 60 Patients with Congenital Hyperinsulinism. Horm Res Paediatr 2018; 89:1-6. [PMID: 29151084 DOI: 10.1159/000481774] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 09/25/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Congenital hyperinsulinism (CHI) is hallmarked by persistent hypoketotic hypoglycemia in infancy. In the majority of all patients, CHI is caused by mutations in the KATP channel genes ABCC8 and KCNJ11, but other genes in the insulin-regulatory pathway have also been described. Repeated episodes of hypoglycemia include an increased risk of seizures and intellectual disability. So far, controlled psychometric studies on cognitive, motor, speech, and social-emotional outcome of CHI patients are missing. Until now, neurodevelopmental long-term outcome in CHI patients has only been measured by questionnaires, self-, parental-, or caregiver-administered instruments. METHODS This is a prospective study of 60 patients (median age 3.3 years, range 3 months to 57 years): 48 with a diffuse, 9 with a focal, and 3 with an atypical histology. Neurodevelopmental outcome was assessed using standardized psychological tests and questionnaires. RESULTS 28 of 60 patients showed developmental delay (46.7%). 9 of 57 patients had cognitive deficits (15.8%), 7 of 26 patients had speech problems (26.9%), and 17 of 44 patients had motor problems (38.6%). In 5 of 53 patients, social-emotional problems were reported. Outcome and the underlying genetic defect were not correlated. CONCLUSIONS Motor problems seem to be prominent in CHI patients. Despite a high incidence of developmental delay, a permanent cognitive defect was only detectable in 9 of 58 patients.
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Affiliation(s)
- Anja Ludwig
- Department of Pediatrics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Simone Enke
- Department of Pediatrics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Janine Heindorf
- Department of Pediatrics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Susann Empting
- Department of Pediatrics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Thomas Meissner
- Department of Pediatrics, University Duesseldorf, Duesseldorf, Germany
| | - Klaus Mohnike
- Department of Pediatrics, Otto von Guericke University Magdeburg, Magdeburg, Germany
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Akasaka M, Kamei A, Araya N, Oyama K, Sasaki M. Characteristic proton magnetic resonance spectroscopy in glucose transporter type 1 deficiency syndrome. Pediatr Int 2018; 60:978-979. [PMID: 30320424 DOI: 10.1111/ped.13672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 07/12/2018] [Accepted: 08/01/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Manami Akasaka
- Department of Pediatrics, School of Medicine, Institute for Biomedical Sciences, Iwate Medical University, Morioka, Iwate, Japan
| | - Atsushi Kamei
- Department of Pediatrics, School of Medicine, Institute for Biomedical Sciences, Iwate Medical University, Morioka, Iwate, Japan
| | - Nami Araya
- Department of Pediatrics, School of Medicine, Institute for Biomedical Sciences, Iwate Medical University, Morioka, Iwate, Japan
| | - Kotaro Oyama
- Department of Pediatrics, School of Medicine, Institute for Biomedical Sciences, Iwate Medical University, Morioka, Iwate, Japan
| | - Makoto Sasaki
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Morioka, Iwate, Japan
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18
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Vodovozov W, Schneider J, Elzoheiry S, Hollnagel JO, Lewen A, Kann O. Metabolic modulation of neuronal gamma-band oscillations. Pflugers Arch 2018; 470:1377-1389. [DOI: 10.1007/s00424-018-2156-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/06/2018] [Accepted: 05/17/2018] [Indexed: 01/08/2023]
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Biochemical phenotyping unravels novel metabolic abnormalities and potential biomarkers associated with treatment of GLUT1 deficiency with ketogenic diet. PLoS One 2017; 12:e0184022. [PMID: 28961260 PMCID: PMC5621665 DOI: 10.1371/journal.pone.0184022] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/30/2017] [Indexed: 11/19/2022] Open
Abstract
Global metabolomic profiling offers novel opportunities for the discovery of biomarkers and for the elucidation of pathogenic mechanisms that might lead to the development of novel therapies. GLUT1 deficiency syndrome (GLUT1-DS) is an inborn error of metabolism due to reduced function of glucose transporter type 1. Clinical presentation of GLUT1-DS is heterogeneous and the disorder mirrors patients with epilepsy, movement disorders, or any paroxysmal events or unexplained neurological manifestation triggered by exercise or fasting. The diagnostic biochemical hallmark of the disease is a reduced cerebrospinal fluid (CSF)/blood glucose ratio and the only available treatment is ketogenic diet. This study aimed at advancing our understanding of the biochemical perturbations in GLUT1-DS pathogenesis through biochemical phenotyping and the treatment of GLUT1-DS with a ketogenic diet. Metabolomic analysis of three CSF samples from GLUT1-DS patients not on ketogenic diet was feasible inasmuch as CSF sampling was used for diagnosis before to start with ketogenic diet. The analysis of plasma and urine samples obtained from GLUT1-DS patients treated with a ketogenic diet showed alterations in lipid and amino acid profiles. While subtle, these were consistent findings across the patients with GLUT1-DS on ketogenic diet, suggesting impacts on mitochondrial physiology. Moreover, low levels of free carnitine were present suggesting its consumption in GLUT1-DS on ketogenic diet. 3-hydroxybutyrate, 3-hydroxybutyrylcarnitine, 3-methyladipate, and N-acetylglycine were identified as potential biomarkers of GLUT1-DS on ketogenic diet. This is the first study to identify CSF, plasma, and urine metabolites associated with GLUT1-DS, as well as biochemical changes impacted by a ketogenic diet. Potential biomarkers and metabolic insights deserve further investigation.
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Espeland MA, Lipska K, Miller ME, Rushing J, Cohen RA, Verghese J, McDermott MM, King AC, Strotmeyer ES, Blair SN, Pahor M, Reid K, Demons J, Kritchevsky SB. Effects of Physical Activity Intervention on Physical and Cognitive Function in Sedentary Adults With and Without Diabetes. J Gerontol A Biol Sci Med Sci 2017; 72:861-866. [PMID: 27590629 DOI: 10.1093/gerona/glw179] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/17/2016] [Indexed: 12/15/2022] Open
Abstract
Background Type 2 diabetes mellitus may alter the effect of physical activity on physical and cognitive function. Methods The Lifestyle Interventions and Independence for Elders (LIFE) trial randomized controlled clinical trial of physical activity intervention (walking, resistance training, and flexibility exercises) enrolled adults aged 70-89 years who were sedentary and non-demented and who had functional limitations. Standardized measures of physical and cognitive function were collected an average of 2 years post-randomization. Differences between the intervention and control groups from 415 individuals with diabetes and 1,061 individuals without diabetes were contrasted with analyses of covariance. Results At 24 months, assignment to the physical activity intervention resulted in 0.019 m/s relatively faster average 400-meter gait speeds (p = .007 overall) both for individuals with and without diabetes (intervention × diabetes interaction p = .99). No benefits were seen on scores from a physical performance battery. Performance on cognitive tests was better among participants assigned to the physical activity intervention compared with control only for those with diabetes, particularly for global cognitive function (p = .02) and delayed memory (p = .005), with mean [95% confidence intervals] for benefit from physical activity intervention of 0.114 [0.007,0.111] and 0.208 [0.030,0.387] standard deviations, respectively. Conclusions Physical activity intervention improved the gait speed of older, sedentary individuals with and without diabetes. The cognitive function benefits occurred among participants with, but not without, diabetes. The mechanisms through which physical activity affects physical and cognitive function in older adults may differ for individuals by diabetes status.
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21
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Kajihara N, Kukidome D, Sada K, Motoshima H, Furukawa N, Matsumura T, Nishikawa T, Araki E. Low glucose induces mitochondrial reactive oxygen species via fatty acid oxidation in bovine aortic endothelial cells. J Diabetes Investig 2017; 8:750-761. [PMID: 28406580 PMCID: PMC5668512 DOI: 10.1111/jdi.12678] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/04/2017] [Accepted: 04/09/2017] [Indexed: 12/19/2022] Open
Abstract
AIMS/INTRODUCTION Overproduction of reactive oxygen species (ROS) in endothelial cells (ECs) plays a pivotal role in endothelial dysfunction. Mitochondrial ROS (mtROS) is one of the key players in the pathogenesis of diabetic vascular complications. Hypoglycemia is linked to increased ROS production and vascular events; however, the underlying mechanisms remain unclear. In the present study, we aimed to determine whether and how low glucose (LG) mediates mtROS generation in ECs, and to examine the impact of LG-induced mtROS on endothelial dysfunction. MATERIALS AND METHODS Metabolomic profiling, cellular oxygen consumption rate, mtROS, endothelial nitric oxide synthase phosphorylation, and the expression of vascular cell adhesion molecule-1 or intercellular adhesion molecule-1 were evaluated in bovine aortic ECs. RESULTS We found that LG increased mtROS generation in ECs; which was suppressed by overexpression of manganese superoxide dismutase. Comprehensive metabolic analysis using capillary electrophoresis-mass spectrometry and oxygen consumption rate assessment showed that the pathway from fatty acid to acetyl-CoA through fatty acid oxidation was upregulated in ECs under LG conditions. In addition, etomoxir, a specific inhibitor of the free fatty acid transporter, decreased LG-induced mtROS production. These results suggested that LG increased mtROS generation through activation of fatty acid oxidation. We further revealed that LG inhibited endothelial nitric oxide synthase phosphorylation, and increased the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. These effects were suppressed either by overexpression of manganese superoxide dismutase or by treatment with etomoxir. CONCLUSIONS The activation of fatty acid oxidation followed by mtROS production could be one of the causes for endothelial dysfunction during hypoglycemia.
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Affiliation(s)
- Nobuhiro Kajihara
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan
| | - Daisuke Kukidome
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan
| | - Kiminori Sada
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan
| | | | - Noboru Furukawa
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan.,Center for Medical Education and Research, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeshi Matsumura
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan
| | - Takeshi Nishikawa
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan.,Department of Diabetes and Endocrinology, National Hospital Organization Kumamoto Medical Center, Kumamoto, Japan
| | - Eiichi Araki
- Department of Metabolic Medicine, Kumamoto University, Kumamoto, Japan
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22
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Zilberter Y, Zilberter M. The vicious circle of hypometabolism in neurodegenerative diseases: Ways and mechanisms of metabolic correction. J Neurosci Res 2017; 95:2217-2235. [PMID: 28463438 DOI: 10.1002/jnr.24064] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 12/13/2022]
Abstract
Hypometabolism, characterized by decreased brain glucose consumption, is a common feature of many neurodegenerative diseases. Initial hypometabolic brain state, created by characteristic risk factors, may predispose the brain to acquired epilepsy and sporadic Alzheimer's and Parkinson's diseases, which are the focus of this review. Analysis of available data suggests that deficient glucose metabolism is likely a primary initiating factor for these diseases, and that resulting neuronal dysfunction further promotes the metabolic imbalance, establishing an effective positive feedback loop and a downward spiral of disease progression. Therefore, metabolic correction leading to the normalization of abnormalities in glucose metabolism may be an efficient tool to treat the neurological disorders by counteracting their primary pathological mechanisms. Published and preliminary experimental results on this approach for treating Alzheimer's disease and epilepsy models support the efficacy of metabolic correction, confirming the highly promising nature of the strategy. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yuri Zilberter
- Aix-Marseille Université, INSERM UMR1106, Institut de Neurosciences des Systèmes, Marseille, France
| | - Misha Zilberter
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California, 94158, USA
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23
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Tups A, Benzler J, Sergi D, Ladyman SR, Williams LM. Central Regulation of Glucose Homeostasis. Compr Physiol 2017; 7:741-764. [DOI: 10.1002/cphy.c160015] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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24
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Iglesias J, Morales L, Barreto GE. Metabolic and Inflammatory Adaptation of Reactive Astrocytes: Role of PPARs. Mol Neurobiol 2016; 54:2518-2538. [PMID: 26984740 DOI: 10.1007/s12035-016-9833-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/04/2016] [Indexed: 01/10/2023]
Abstract
Astrocyte-mediated inflammation is associated with degenerative pathologies such as Alzheimer's and Parkinson's diseases and multiple sclerosis. The acute inflammation and morphological and metabolic changes that astrocytes develop after the insult are known as reactive astroglia or astrogliosis that is an important response to protect and repair the lesion. Astrocytes optimize their metabolism to produce lactate, glutamate, and ketone bodies in order to provide energy to the neurons that are deprived of nutrients upon insult. Firstly, we review the basis of inflammation and morphological changes of the different cell population implicated in reactive gliosis. Next, we discuss the more active metabolic pathways in healthy astrocytes and explain the metabolic response of astrocytes to the insult in different pathologies and which metabolic alterations generate complications in these diseases. We emphasize the role of peroxisome proliferator-activated receptors isotypes in the inflammatory and metabolic adaptation of astrogliosis developed in ischemia or neurodegenerative diseases. Based on results reported in astrocytes and other cells, we resume and hypothesize the effect of peroxisome proliferator-activated receptor (PPAR) activation with ligands on different metabolic pathways in order to supply energy to the neurons. The activation of selective PPAR isotype activity may serve as an input to better understand the role played by these receptors on the metabolic and inflammatory compensation of astrogliosis and might represent an opportunity to develop new therapeutic strategies against traumatic brain injuries and neurodegenerative diseases.
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Affiliation(s)
- José Iglesias
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, DC, Colombia.
| | - Ludis Morales
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, DC, Colombia
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, DC, Colombia
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
- Universidad Científica del Sur, Lima, Peru
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25
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Koivisto H, Leinonen H, Puurula M, Hafez HS, Barrera GA, Stridh MH, Waagepetersen HS, Tiainen M, Soininen P, Zilberter Y, Tanila H. Chronic Pyruvate Supplementation Increases Exploratory Activity and Brain Energy Reserves in Young and Middle-Aged Mice. Front Aging Neurosci 2016; 8:41. [PMID: 27014054 PMCID: PMC4794631 DOI: 10.3389/fnagi.2016.00041] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/15/2016] [Indexed: 01/09/2023] Open
Abstract
Numerous studies have reported neuroprotective effects of pyruvate when given in systemic injections. Impaired glucose uptake and metabolism are found in Alzheimer's disease (AD) and in AD mouse models. We tested whether dietary pyruvate supplementation is able to provide added energy supply to brain and thereby attenuate aging- or AD-related cognitive impairment. Mice received ~800 mg/kg/day Na-pyruvate in their chow for 2-6 months. In middle-aged wild-type mice and in 6.5-month-old APP/PS1 mice, pyruvate facilitated spatial learning and increased exploration of a novel odor. However, in passive avoidance task for fear memory, the treatment group was clearly impaired. Independent of age, long-term pyruvate increased explorative behavior, which likely explains the paradoxical impairment in passive avoidance. We also assessed pyruvate effects on body weight, muscle force, and endurance, and found no effects. Metabolic postmortem assays revealed increased energy compounds in nuclear magnetic resonance spectroscopy as well as increased brain glycogen storages in the pyruvate group. Pyruvate supplementation may counteract aging-related behavioral impairment, but its beneficial effect seems related to increased explorative activity rather than direct memory enhancement.
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Affiliation(s)
| | - Henri Leinonen
- A. I. Virtanen Institute, University of Eastern Finland , Kuopio , Finland
| | - Mari Puurula
- A. I. Virtanen Institute, University of Eastern Finland , Kuopio , Finland
| | - Hani Sayed Hafez
- Biology Department, Faculty of Science, Suez University , Suez , Egypt
| | | | - Malin H Stridh
- Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Helle S Waagepetersen
- Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Mika Tiainen
- NMR Metabolomics Laboratory, School of Pharmacy, University of Eastern Finland , Kuopio , Finland
| | - Pasi Soininen
- NMR Metabolomics Laboratory, School of Pharmacy, University of Eastern Finland , Kuopio , Finland
| | - Yuri Zilberter
- Institut national de la santé et de la recherche médicale UMR_S 1106, Institut de Neurosciences des Systèmes, Aix-Marseille Université , Marseille , France
| | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland , Kuopio , Finland
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Glucose, Lactate, β-Hydroxybutyrate, Acetate, GABA, and Succinate as Substrates for Synthesis of Glutamate and GABA in the Glutamine-Glutamate/GABA Cycle. ADVANCES IN NEUROBIOLOGY 2016; 13:9-42. [PMID: 27885625 DOI: 10.1007/978-3-319-45096-4_2] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The glutamine-glutamate/GABA cycle is an astrocytic-neuronal pathway transferring precursors for transmitter glutamate and GABA from astrocytes to neurons. In addition, the cycle carries released transmitter back to astrocytes, where a minor fraction (~25 %) is degraded (requiring a similar amount of resynthesis) and the remainder returned to the neurons for reuse. The flux in the cycle is intense, amounting to the same value as neuronal glucose utilization rate or 75-80 % of total cortical glucose consumption. This glucose:glutamate ratio is reduced when high amounts of β-hydroxybutyrate are present, but β-hydroxybutyrate can at most replace 60 % of glucose during awake brain function. The cycle is initiated by α-ketoglutarate production in astrocytes and its conversion via glutamate to glutamine which is released. A crucial reaction in the cycle is metabolism of glutamine after its accumulation in neurons. In glutamatergic neurons all generated glutamate enters the mitochondria and its exit to the cytosol occurs in a process resembling the malate-aspartate shuttle and therefore requiring concomitant pyruvate metabolism. In GABAergic neurons one half enters the mitochondria, whereas the other one half is released directly from the cytosol. A revised concept is proposed for the synthesis and metabolism of vesicular and nonvesicular GABA. It includes the well-established neuronal GABA reuptake, its metabolism, and use for resynthesis of vesicular GABA. In contrast, mitochondrial glutamate is by transamination to α-ketoglutarate and subsequent retransamination to releasable glutamate essential for the transaminations occurring during metabolism of accumulated GABA and subsequent resynthesis of vesicular GABA.
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Libby AE, Wang H, Mittal R, Sungelo M, Potma E, Eckel RH. Lipoprotein lipase is an important modulator of lipid uptake and storage in hypothalamic neurons. Biochem Biophys Res Commun 2015; 465:287-92. [PMID: 26265042 DOI: 10.1016/j.bbrc.2015.08.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/06/2015] [Indexed: 11/28/2022]
Abstract
LPL is the rate-limiting enzyme for uptake of TG-derived FFA in peripheral tissues, and the enzyme is expressed in the brain and CNS. We previously created a mouse which lacks neuronal LPL. This animal becomes obese on a standard chow, and we observed reduced lipid uptake in the hypothalamus at 3 months preceding obesity. In our present study, we replicated the animal phenotype in an immortalized mouse hypothalamic cell line (N41) to examine how LPL affects expression of AgRP as well as entry and storage of lipids into neurons. We show that LPL is able to modulate levels of the orexigenic peptide AgRP. LPL also exerts effects on lipid uptake into culture neurons, and that uptake of neutral lipid can be enhanced even by mutant LPL lacking catalytic activity. N41 cells also accumulate neutral lipid in droplets, and this is at least in part regulated by LPL. These data in addition to those published in mice with neuron-specific deletion of LPL suggest that neuronal LPL is an important regulator of lipid homeostasis in neurons and that alterations in LPL levels may have important effects on systemic metabolism and neuronal lipid biology.
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Affiliation(s)
- Andrew E Libby
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA.
| | - Hong Wang
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA
| | - Richa Mittal
- Beckman Laser Institute, University of California, Irvine, USA
| | - Mitchell Sungelo
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA
| | - Eric Potma
- Beckman Laser Institute, University of California, Irvine, USA
| | - Robert H Eckel
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA
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28
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Abstract
Over the last two decades, several genes have been identified that appear to play a role in the regulation of energy homeostasis and body weight. For a small subset of them, a reduction or an absence of expression confers a resistance to the development of obesity. Recently, a knockin mouse for a member of the monocarboxylate transporter (MCT) family, MCT1, was demonstrated to exhibit a typical phenotype of resistance to diet-induced obesity and a protection from its associated metabolic perturbations. Such findings point out at MCTs as putatively new therapeutic targets in the context of obesity. Here, we will review what is known about MCTs and their possible metabolic roles in different organs and tissues. Based on the description of the phenotype of the MCT1 knockin mouse, we will also provide some insights about their putative roles in weight gain regulation.
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Affiliation(s)
- L Carneiro
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
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29
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Glycemic Variability and Acute Ischemic Stroke: The Missing Link? Transl Stroke Res 2014; 5:638-46. [DOI: 10.1007/s12975-014-0365-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 07/19/2014] [Accepted: 07/28/2014] [Indexed: 12/20/2022]
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30
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Glycolysis and oxidative phosphorylation in neurons and astrocytes during network activity in hippocampal slices. J Cereb Blood Flow Metab 2014; 34:397-407. [PMID: 24326389 PMCID: PMC3948126 DOI: 10.1038/jcbfm.2013.222] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 12/14/2022]
Abstract
Network activation triggers a significant energy metabolism increase in both neurons and astrocytes. Questions of the primary neuronal energy substrate (e.g., glucose vs. lactate) as well as the relative contributions of glycolysis and oxidative phosphorylation and their cellular origin (neurons vs. astrocytes) are still a matter of debates. Using simultaneous measurements of electrophysiological and metabolic parameters during synaptic stimulation in hippocampal slices from mature mice, we show that neurons and astrocytes use both glycolysis and oxidative phosphorylation to meet their energy demands. Supplementation or replacement of glucose in artificial cerebrospinal fluid (ACSF) with pyruvate or lactate strongly modifies parameters related to network activity-triggered energy metabolism. These effects are not induced by changes in ATP content, pH(i), [Ca(2+)](i) or accumulation of reactive oxygen species. Our results suggest that during network activation, a significant fraction of NAD(P)H response (its overshoot phase) corresponds to glycolysis and the changes in cytosolic NAD(P)H and mitochondrial FAD are coupled. Our data do not support the hypothesis of a preferential utilization of astrocyte-released lactate by neurons during network activation in slices--instead, we show that during such activity glucose is an effective energy substrate for both neurons and astrocytes.
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31
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Moffett JR, Arun P, Ariyannur PS, Namboodiri AMA. N-Acetylaspartate reductions in brain injury: impact on post-injury neuroenergetics, lipid synthesis, and protein acetylation. FRONTIERS IN NEUROENERGETICS 2013; 5:11. [PMID: 24421768 PMCID: PMC3872778 DOI: 10.3389/fnene.2013.00011] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 12/09/2013] [Indexed: 12/22/2022]
Abstract
N-Acetylaspartate (NAA) is employed as a non-invasive marker for neuronal health using proton magnetic resonance spectroscopy (MRS). This utility is afforded by the fact that NAA is one of the most concentrated brain metabolites and that it produces the largest peak in MRS scans of the healthy human brain. NAA levels in the brain are reduced proportionately to the degree of tissue damage after traumatic brain injury (TBI) and the reductions parallel the reductions in ATP levels. Because NAA is the most concentrated acetylated metabolite in the brain, we have hypothesized that NAA acts in part as an extensive reservoir of acetate for acetyl coenzyme A synthesis. Therefore, the loss of NAA after TBI impairs acetyl coenzyme A dependent functions including energy derivation, lipid synthesis, and protein acetylation reactions in distinct ways in different cell populations. The enzymes involved in synthesizing and metabolizing NAA are predominantly expressed in neurons and oligodendrocytes, respectively, and therefore some proportion of NAA must be transferred between cell types before the acetate can be liberated, converted to acetyl coenzyme A and utilized. Studies have indicated that glucose metabolism in neurons is reduced, but that acetate metabolism in astrocytes is increased following TBI, possibly reflecting an increased role for non-glucose energy sources in response to injury. NAA can provide additional acetate for intercellular metabolite trafficking to maintain acetyl CoA levels after injury. Here we explore changes in NAA, acetate, and acetyl coenzyme A metabolism in response to brain injury.
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Affiliation(s)
- John R. Moffett
- Neuroscience Program, Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health SciencesBethesda, MD, USA
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32
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Gray LR, Tompkins SC, Taylor EB. Regulation of pyruvate metabolism and human disease. Cell Mol Life Sci 2013; 71:2577-604. [PMID: 24363178 PMCID: PMC4059968 DOI: 10.1007/s00018-013-1539-2] [Citation(s) in RCA: 514] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 11/24/2013] [Accepted: 12/02/2013] [Indexed: 12/31/2022]
Abstract
Pyruvate is a keystone molecule critical for numerous aspects of eukaryotic and human metabolism. Pyruvate is the end-product of glycolysis, is derived from additional sources in the cellular cytoplasm, and is ultimately destined for transport into mitochondria as a master fuel input undergirding citric acid cycle carbon flux. In mitochondria, pyruvate drives ATP production by oxidative phosphorylation and multiple biosynthetic pathways intersecting the citric acid cycle. Mitochondrial pyruvate metabolism is regulated by many enzymes, including the recently discovered mitochondria pyruvate carrier, pyruvate dehydrogenase, and pyruvate carboxylase, to modulate overall pyruvate carbon flux. Mutations in any of the genes encoding for proteins regulating pyruvate metabolism may lead to disease. Numerous cases have been described. Aberrant pyruvate metabolism plays an especially prominent role in cancer, heart failure, and neurodegeneration. Because most major diseases involve aberrant metabolism, understanding and exploiting pyruvate carbon flux may yield novel treatments that enhance human health.
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Affiliation(s)
- Lawrence R Gray
- Department of Biochemistry, Fraternal Order of the Eagles Diabetes Research Center, and François M. Abboud Cardiovascular Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 51 Newton Rd, 4-403 BSB, Iowa City, IA, 52242, USA
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Pardo B, Contreras L, Satrústegui J. De novo Synthesis of Glial Glutamate and Glutamine in Young Mice Requires Aspartate Provided by the Neuronal Mitochondrial Aspartate-Glutamate Carrier Aralar/AGC1. Front Endocrinol (Lausanne) 2013; 4:149. [PMID: 24133485 PMCID: PMC3796713 DOI: 10.3389/fendo.2013.00149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/02/2013] [Indexed: 01/14/2023] Open
Affiliation(s)
- Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain
- *Correspondence:
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain
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Lovern D, Marbois B. Does menaquinone participate in brain astrocyte electron transport? Med Hypotheses 2013; 81:587-91. [PMID: 23910074 DOI: 10.1016/j.mehy.2013.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 06/25/2013] [Accepted: 07/03/2013] [Indexed: 02/03/2023]
Abstract
UNLABELLED Quinone compounds act as membrane resident carriers of electrons between components of the electron transport chain in the periplasmic space of prokaryotes and in the mitochondria of eukaryotes. Vitamin K is a quinone compound in the human body in a storage form as menaquinone (MK); distribution includes regulated amounts in mitochondrial membranes. The human brain, which has low amounts of typical vitamin K dependent function (e.g., gamma carboxylase) has relatively high levels of MK, and different regions of brain have different amounts. Coenzyme Q (Q), is a quinone synthesized de novo, and the levels of synthesis decline with age. The levels of MK are dependent on dietary intake and generally increase with age. MK has a characterized role in the transfer of electrons to fumarate in prokaryotes. A newly recognized fumarate cycle has been identified in brain astrocytes. The MK precursor menadione has been shown to donate electrons directly to mitochondrial complex III. HYPOTHESIS Vitamin K compounds function in the electron transport chain of human brain astrocytes.
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Affiliation(s)
- Douglas Lovern
- BioMérieux, 100 Rodolphe Dr., Durham, NC 27712, United States
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35
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Astrocytic energetics during excitatory neurotransmission: What are contributions of glutamate oxidation and glycolysis? Neurochem Int 2013; 63:244-58. [PMID: 23838211 DOI: 10.1016/j.neuint.2013.06.015] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/19/2013] [Accepted: 06/24/2013] [Indexed: 12/23/2022]
Abstract
Astrocytic energetics of excitatory neurotransmission is controversial due to discrepant findings in different experimental systems in vitro and in vivo. The energy requirements of glutamate uptake are believed by some researchers to be satisfied by glycolysis coupled with shuttling of lactate to neurons for oxidation. However, astrocytes increase glycogenolysis and oxidative metabolism during sensory stimulation in vivo, indicating that other sources of energy are used by astrocytes during brain activation. Furthermore, glutamate uptake into cultured astrocytes stimulates glutamate oxidation and oxygen consumption, and glutamate maintains respiration as well as glucose. The neurotransmitter pool of glutamate is associated with the faster component of total glutamate turnover in vivo, and use of neurotransmitter glutamate to fuel its own uptake by oxidation-competent perisynaptic processes has two advantages, substrate is supplied concomitant with demand, and glutamate spares glucose for use by neurons and astrocytes. Some, but not all, perisynaptic processes of astrocytes in adult rodent brain contain mitochondria, and oxidation of only a small fraction of the neurotransmitter glutamate taken up into these structures would be sufficient to supply the ATP required for sodium extrusion and conversion of glutamate to glutamine. Glycolysis would, however, be required in perisynaptic processes lacking oxidative capacity. Three lines of evidence indicate that critical cornerstones of the astrocyte-to-neuron lactate shuttle model are not established and normal brain does not need lactate as supplemental fuel: (i) rapid onset of hemodynamic responses to activation delivers oxygen and glucose in excess of demand, (ii) total glucose utilization greatly exceeds glucose oxidation in awake rodents during activation, indicating that the lactate generated is released, not locally oxidized, and (iii) glutamate-induced glycolysis is not a robust phenotype of all astrocyte cultures. Various metabolic pathways, including glutamate oxidation and glycolysis with lactate release, contribute to cellular energy demands of excitatory neurotransmission.
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Abstract
Astrocytes are the predominant glial cell population in the central nervous system (CNS). Once considered only passive scaffolding elements, astrocytes are now recognised as cells playing essential roles in CNS development and function. They control extracellular water and ion homeostasis, provide substrates for energy metabolism, and regulate neurogenesis, myelination and synaptic transmission. Due to these multiple activities astrocytes have been implicated in almost all brain pathologies, contributing to various aspects of disease initiation, progression and resolution. Evidence is emerging that astrocyte dysfunction can be the direct cause of neurodegeneration, as shown in Alexander's disease where myelin degeneration is caused by mutations in the gene encoding the astrocyte-specific cytoskeleton protein glial fibrillary acidic protein. Recent studies point to a primary role for astrocytes in the pathogenesis of other genetic leukodystrophies such as megalencephalic leukoencephalopathy with subcortical cysts and vanishing white matter disease. The aim of this review is to summarize current knowledge of the pathophysiological role of astrocytes focusing on their contribution to the development of the above mentioned leukodystrophies and on new perspectives for the treatment of neurological disorders.
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