Dependence of glucose transport in neuronal model systems on autophagy and GAPDH (glyceraldehyde-3 phosphate dehydrogenase) activity

Pseudomonas aeruginosa (isolated from soil) synthesizes an alkylsulfatase allowing this bacterium to utilize sodium hexan-1-yl sulfate as a source of carbon and sulfur for growth. The formation of the enzyme was induced by this and by other (C4–C16) primary alkylsulfate esters as well as by some (C-8 and C-9) primary alkylsulfonates. Secondary (2-yl) alkylsulfate esters did not act as inducers. The induction of alkylsulfatase was markedly inhibited by L-cysteine, L-methionine, sodium sulfide, and by high (>2 mM) concentrations of D-glucose and other related monosaccharides. Similar inhibitory effects by four glucose analogs which will not support growth suggest that prior metabolism was not a requirement for glucose-mediated inhibition. The inhibition by D-glucose of the same inducible system in P. aeruginosa (PAO-57) supported this conclusion since this glucose transport-positive mutant is deficient in the further metabolism of the monosaccharide. At low (0.1–1.0 mM) concentrations, D-glucose or D-glucose 6-O-phosphate (20 mM) caused a marked enhancement of alkylsulfatase induction in the isolate. This novel enhancement was reproduced using P. aeruginosa strain PAO. However, both monosaccharides acted as potent inhibitors of alkylsulfatase formation occurring in mutant PAO-57 which, unlike the parent strain PAO, exhibits low glucose-6-phosphate dehydrogenase activity. These results suggest that D-glucose (0.1–1.0 mM) must be metabolized to enhance the synthesis of the enzyme.

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Stimulation of pyruvate dehydrogenase activity in adipocytes by oxytocin: Evidence for mediation of the insulin-like effect by endogenous hydrogen peroxide independent of glucose transport

Archives of Biochemistry and Biophysics ◽

10.1016/0003-9861(82)90024-8 ◽

1982 ◽

Vol 214 (1) ◽

pp. 211-222 ◽

Cited By ~ 15

Author(s):

Sakti Prasad Mukherjee ◽

Chhabirani Mukherjee

Keyword(s):

Hydrogen Peroxide ◽

Dehydrogenase Activity ◽

Glucose Transport ◽

Pyruvate Dehydrogenase ◽

Stimulation Of

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Disruption of The Psychiatric Risk Gene Ankyrin 3 Enhances Microtubule Dynamics Through GSK3/CRMP2 Signaling

10.1101/303990 ◽

2018 ◽

Author(s):

Jacob C Garza ◽

Xiaoli Qi ◽

Klaudio Gjeluci ◽

Melanie P Leussis ◽

Himanish Basu ◽

...

Keyword(s):

Psychiatric Illness ◽

Molecular Mechanisms ◽

Glycogen Synthase ◽

Binding Protein ◽

Neuronal Model ◽

Microtubule Dynamics ◽

Model Systems ◽

Altered Expression ◽

Risk Gene ◽

Tubulin Acetylation

AbstractThe ankyrin 3 gene (ANK3) is a well-established risk gene for psychiatric illness, but the mechanisms underlying its pathophysiology remain elusive. We examined the molecular effects of disrupting brain-specific Ank3 isoforms in mouse and neuronal model systems. RNA sequencing of hippocampus from Ank3+/- and Ank3+/+ mice identified altered expression of 282 genes that were enriched for microtubule-related functions. Results were supported by increased expression of microtubule end-binding protein 3 (EB3), an indicator of microtubule dynamics, in Ank3+/- mouse hippocampus. Live-cell imaging of EB3 movement in primary neurons from Ank3+/- mice revealed impaired elongation of microtubules. Using a CRISPR-dCas9-KRAB transcriptional repressor in mouse neuro-2a cells, we determined that repression of brain-specific Ank3 increased EB3 expression, decreased tubulin acetylation, and increased the soluble:polymerized tubulin ratio, indicating enhanced microtubule dynamics. These changes were rescued by inhibition of glycogen synthase kinase 3 (GSK3) with lithium or CHIR99021, a highly selective GSK3 inhibitor. Brain-specific Ank3 repression in neuro-2a cells increased GSK3 activity (reduced inhibitory phosphorylation) and elevated collapsin response mediator protein 2 (CRMP2) phosphorylation, a known GSK3 substrate and microtubule-binding protein. Pharmacological inhibition of CRMP2 activity attenuated the rescue of EB3 expression and tubulin polymerization in Ank3 repressed cells by lithium or CHIR99021, suggesting microtubule instability induced by Ank3 repression is dependent on CRMP2 activity. Taken together, our data indicate that aNK3 functions in neuronal microtubule dynamics through GSK3 and its downstream substrate CRMP2. These findings reveal cellular and molecular mechanisms underlying brain-specific ANK3 disruption that may be related to its role in psychiatric illness.

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Will the original glucose transporter isoform please stand up!

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00496.2009 ◽

2009 ◽

Vol 297 (4) ◽

pp. E836-E848 ◽

Cited By ~ 111

Author(s):

Anthony Carruthers ◽

Julie DeZutter ◽

Amit Ganguly ◽

Sherin U. Devaskar

Keyword(s):

Glucose Transport ◽

Cell Biology ◽

Posttranscriptional Regulation ◽

Glucose Transporter ◽

Sugar Transport ◽

Deficiency Syndrome ◽

Model Systems ◽

Glut1 Expression ◽

Glut1 Deficiency ◽

Membrane Spanning

Monosaccharides enter cells by slow translipid bilayer diffusion by rapid, protein-mediated, cation-dependent cotransport and by rapid, protein-mediated equilibrative transport. This review addresses protein-mediated, equilibrative glucose transport catalyzed by GLUT1, the first equilibrative glucose transporter to be identified, purified, and cloned. GLUT1 is a polytopic, membrane-spanning protein that is one of 13 members of the human equilibrative glucose transport protein family. We review GLUT1 catalytic and ligand-binding properties and interpret these behaviors in the context of several putative mechanisms for protein-mediated transport. We conclude that no single model satisfactorily explains GLUT1 behavior. We then review GLUT1 topology, subunit architecture, and oligomeric structure and examine a new model for sugar transport that combines structural and kinetic analyses to satisfactorily reproduce GLUT1 behavior in human erythrocytes. We next review GLUT1 cell biology and the transcriptional and posttranscriptional regulation of GLUT1 expression in the context of development and in response to glucose perturbations and hypoxia in blood-tissue barriers. Emphasis is placed on transgenic GLUT1 overexpression and null mutant model systems, the latter serving as surrogates for the human GLUT1 deficiency syndrome. Finally, we review the role of GLUT1 in the absence or deficiency of a related isoform, GLUT3, toward establishing the physiological significance of coordination between these two isoforms.

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α-Synuclein–induced lysosomal dysfunction occurs through disruptions in protein trafficking in human midbrain synucleinopathy models

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1520335113 ◽

2016 ◽

Vol 113 (7) ◽

pp. 1931-1936 ◽

Cited By ~ 148

Author(s):

Joseph R. Mazzulli ◽

Friederike Zunke ◽

Ole Isacson ◽

Lorenz Studer ◽

Dimitri Krainc

Keyword(s):

Protein Trafficking ◽

Neurodegenerative Disorder ◽

Neuronal Model ◽

Model Systems ◽

Lysosomal Degradation ◽

Major Barrier ◽

Age Related ◽

Golgi Structure ◽

Midbrain Dopamine ◽

Precise Role

Parkinson’s disease (PD) is an age-related neurodegenerative disorder characterized by the accumulation of protein aggregates comprised of α-synuclein (α-syn). A major barrier in treatment discovery for PD is the lack of identifiable therapeutic pathways capable of reducing aggregates in human neuronal model systems. Mutations in key components of protein trafficking and cellular degradation machinery represent important risk factors for PD; however, their precise role in disease progression and interaction with α-syn remains unclear. Here, we find that α-syn accumulation reduced lysosomal degradation capacity in human midbrain dopamine models of synucleinopathies through disrupting hydrolase trafficking. Accumulation of α-syn at the cell body resulted in aberrant association with cis-Golgi–tethering factor GM130 and disrupted the endoplasmic reticulum-Golgi localization of rab1a, a key mediator of vesicular transport. Overexpression of rab1a restored Golgi structure, improved hydrolase trafficking and activity, and reduced pathological α-syn in patient neurons. Our work suggests that enhancement of lysosomal hydrolase trafficking may prove beneficial in synucleinopathies and indicates that human midbrain disease models may be useful for identifying critical therapeutic pathways in PD and related disorders.

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Potato product form impacts in vitro starch digestibility and glucose transport but only modestly impacts 24 h blood glucose response in humans

Food & Function ◽

10.1039/c8fo02530d ◽

2019 ◽

Vol 10 (4) ◽

pp. 1846-1855 ◽

Cited By ~ 4

Author(s):

Min Li ◽

Judy George ◽

Stephanie Hunter ◽

Bruce Hamaker ◽

Richard Mattes ◽

...

Keyword(s):

Blood Glucose ◽

Phenolic Compounds ◽

Glucose Transport ◽

Model Systems ◽

Product Form ◽

Starch Digestibility ◽

Glucose Response ◽

In Vitro Starch Digestibility ◽

Potato Product

Potatoes are rich in phenolic compounds which have been reported to impact starch digestion and intestinal glucose transport in model systems through phenolic–starch interactions.

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Effects of acute and chronic exercise on skeletal muscle glucose transport in aged rats

Journal of Applied Physiology ◽

10.1152/jappl.1995.78.5.1750 ◽

1995 ◽

Vol 78 (5) ◽

pp. 1750-1756 ◽

Cited By ~ 7

Author(s):

J. F. Youngren ◽

R. J. Barnard

Keyword(s):

Skeletal Muscle ◽

Exercise Training ◽

Dehydrogenase Activity ◽

Glucose Transport ◽

Acute Exercise ◽

Treadmill Running ◽

Aged Rats ◽

Chronic Exercise ◽

Glut 4 ◽

Muscle Glucose Transport

The purpose of this study was to investigate the effects of acute and chronic exercise on skeletal muscle glucose transport in aged rats by using an isolated sarcolemmal membrane preparation. In 24-mo-old female Fischer 344 rats, a maximum dose of insulin increased glucose transport from 43 +/- 6 to 82 +/- 6 pmol.mg protein-1.15 s-1. A 45-min bout of exhaustive treadmill running increased glucose transport to the same maximum level (88 +/- 5 pmol.mg protein-1.15 s-1). Eight weeks of progressive exercise training resulted in a 65% increase in succinic dehydrogenase activity in hindlimb muscles and a 55% increase in total cellular GLUT-4 content. Despite these biochemical adaptations, there was no change in either basal or maximum insulin-stimulated glucose transport between control (43 +/- 6 and 82 +/- 6 pmol.mg protein-1.15 s-1, respectively) and trained (42 +/- 2 and 82 +/- 8 pmol.mg protein-1.15 s-1, respectively) animals. When hindlimb muscle succinate dehydrogenase activity and GLUT-4 content were compared for both the combined sedentary and trained groups, a significant correlation (r = 0.68) was obtained. This study demonstrates that the skeletal muscle glucose transport system of 24-mo-old rats is fully stimulated by acute exercise and that, although GLUT-4 levels are increased in aged animals after exercise training, this does not result in an enhancement of maximal insulin-stimulated glucose transport. Thus increases in GLUT-4 are not sufficient to improve muscle insulin responsiveness with training.

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SH-SY5Y-derived neurons: A Human Neuronal Model System for Investigating TAU Sorting and Neuronal Subtype-Specific TAU Vulnerability

10.20944/preprints202006.0203.v2 ◽

2020 ◽

Author(s):

Michael Bell ◽

Hans Zempel

Keyword(s):

Human Brain ◽

Intracellular Localization ◽

Neuronal Model ◽

Model Systems ◽

Nucleus Basalis ◽

Human Neuroblastoma Cell ◽

Suitable Model ◽

Human Neuroblastoma ◽

Age Related ◽

Neuronal Subtype

The microtubule-associated protein TAU is sorted into the axon in healthy brain neurons. Somatodendritic missorting of TAU is a pathological hallmark of many neurodegenerative diseases called tauopathies, including Alzheimer’s Disease (AD). Cause, consequence, and (patho)physiological mechanisms of TAU sorting and missorting are understudied, in part also due to the lack of readily available human neuronal model systems. The human neuroblastoma cell line SH-SY5Y is widely used for studying TAU physiology and TAU-related pathology in AD and related tauopathies. SH-SY5Y cells can be differentiated into neuron-like cells (SH-SY5Y-derived neurons) using various substances. This review evaluates whether SH-SY5Y-derived neurons are a suitable model for i) investigating intracellular TAU sorting in general, and ii) with respect to neuron subtype-specific TAU vulnerability. I) SH-SY5Y-derived neurons show pronounced axodendritic polarity, high levels of axonally localized TAU protein, expression of all six major human brain isoforms, and TAU phosphorylation similar to the human brain. As proliferative cells, SH-SY5Y cells are readily accessible for genetic engineering, stable transgene integration and leading-edge genome editing are valuable and promising tools for TAU-related studies. II) Depending on the used differentiation procedure, SH-SY5Y-derived neurons resemble cells of distinct subcortical nuclei, i.e. the Locus coeruleus (LC), Nucleus basalis (NB) and Substantia nigra (SN), all of which early affected in many tauopathies. This allows to analyse neuron-specific TAU isoform expression and intracellular localization, also in the context of vulnerability to TAU pathology. Limitations are e.g. the lack of mimicking age-related tauopathy risk factors and the difficulty to define the exact neuronal subtype of SH-SY5Y-derived neurons. In brief, this review discusses the suitability of SH-SY5Y-derived neurons for investigating TAU (mis)sorting mechanisms and neuron-specific TAU vulnerability in disease paradigms.

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