scholarly journals Glutamatergic and GABAergic TCA Cycle and Neurotransmitter Cycling Fluxes in Different Regions of Mouse Brain

2013 ◽  
Vol 33 (10) ◽  
pp. 1523-1531 ◽  
Author(s):  
Vivek Tiwari ◽  
Susmitha Ambadipudi ◽  
Anant B Patel
Keyword(s):  
Cerebral Cortex ◽  
Mouse Brain ◽  
Ex Vivo ◽  
Tca Cycle ◽  
Metabolic Model ◽  
Nmr Studies ◽  
Inhibitory Function ◽  
The Tca Cycle ◽  
The Brain ◽  
C Nmr

The 13C nuclear magnetic resonance (NMR) studies together with the infusion of 13C-labeled substrates in rats and humans have provided important insight into brain energy metabolism. In the present study, we have extended a three-compartment metabolic model in mouse to investigate glutamatergic and GABAergic tricarboxylic acid (TCA) cycle and neurotransmitter cycle fluxes across different regions of the brain. The 13C turnover of amino acids from [1,6-13C2]glucose was monitored ex vivo using qH-[13C]-NMR spectroscopy. The astroglial glutamate pool size, one of the important parameters of the model, was estimated by a short infusion of [2-13C]acetate. The ratio Vcyc/VTCA was calculated from the steady-state acetate experiment. The 13C turnover curves of [4-13C]/[3-13C]glutamate, [4-13C]glutamine, [2-13C]/[3-13C]GABA, and [3-13C]aspartate from [1,6-13C2]glucose were analyzed using a three-compartment metabolic model to estimate the rates of the TCA cycle and neurotransmitter cycle associated with glutamatergic and GABAergic neurons. The glutamatergic TCA cycle rate was found to be highest in the cerebral cortex (0.91±0.05 μmol/g per minute) and least in the hippocampal region (0.64±0.07 μmol/g per minute) of the mouse brain. In contrast, the GABAergic TCA cycle flux was found to be highest in the thalamus-hypothalamus (0.28±0.01 μmol/g per minute) and least in the cerebral cortex (0.24±0.02 μmol/g per minute). These findings indicate that the energetics of excitatory and inhibitory function is distinct across the mouse brain.

scholarly journals Characterization of Cerebral Glutamine Uptake from Blood in the Mouse Brain: Implications for Metabolic Modeling of 13C NMR Data

2014 ◽  
Vol 34 (10) ◽  
pp. 1666-1672 ◽  
Author(s):  
Puneet Bagga ◽  
Kevin L Behar ◽  
Graeme F Mason ◽  
Henk M De Feyter ◽  
Douglas L Rothman ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Metabolic Model ◽  
Synthesis Rate ◽  
Nmr Studies ◽  
Nmr Data ◽  
Glutamine Synthesis ◽  
Time Courses ◽  
Glutamine Uptake ◽  
C Nmr

13C Nuclear Magnetic Resonance (NMR) studies of rodent and human brain using [1-13C]/[1,6-13C2]glucose as labeled substrate have consistently found a lower enrichment (~25% to 30%) of glutamine-C4 compared with glutamate-C4 at isotopic steady state. The source of this isotope dilution has not been established experimentally but may potentially arise either from blood/brain exchange of glutamine or from metabolism of unlabeled substrates in astrocytes, where glutamine synthesis occurs. In this study, the contribution of the former was evaluated ex vivo using 1H-[13C]-NMR spectroscopy together with intravenous infusion of [U-13C5]glutamine for 3, 15, 30, and 60 minutes in mice. 13C labeling of brain glutamine was found to be saturated at plasma glutamine levels > 1.0 mmol/L. Fitting a blood–astrocyte–neuron metabolic model to the 13C enrichment time courses of glutamate and glutamine yielded the value of glutamine influx, VGln(in), 0.036 ± 0.002 μmol/g per minute for plasma glutamine of 1.8 mmol/L. For physiologic plasma glutamine level (~0.6 mmol/L), VGln(in) would be ~0.010 μmol/g per minute, which corresponds to ~6% of the glutamine synthesis rate and rises to ~11% for saturating blood glutamine concentrations. Thus, glutamine influx from blood contributes at most ~20% to the dilution of astroglial glutamine-C4 consistently seen in metabolic studies using [1-13C]glucose.

scholarly journals Glycolysis versus TCA Cycle in the Primate Brain as Measured by Combining 18F-FDG PET and 13C-NMR

2005 ◽  
Vol 25 (11) ◽  
pp. 1418-1423 ◽  
Author(s):  
Fawzi Boumezbeur ◽  
Laurent Besret ◽  
Julien Valette ◽  
Marie-Claude Gregoire ◽  
Thierry Delzescaux ◽  
...  
Keyword(s):  
Tca Cycle ◽  
Glycolytic Flux ◽  
Cerebral Metabolic Rate ◽  
Metabolic Coupling ◽  
Primate Brain ◽  
Positron Emission ◽  
The Tca Cycle ◽  
The Brain ◽  
Good Agreement ◽  
C Nmr

The glycolytic flux (cerebral metabolic rate of glucose CMRglc) and the TCA cycle flux ( VTCA) were measured in the same monkeys by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and 13C NMR spectroscopy, respectively. Registration of nuclear magnetic resonance (NMR) and PET data were used for comparison of CMRglc and VTCA in the exact same area of the brain. Both fluxes were in good agreement with literature values (CMR glc 0.23 ± 0.03 μmol/g min, VTCA = 0.53 ± 0.13 μmol/gmin). The resulting [ CMRglc/VTCA] ratio was 0.46 ± 0.12 ( n = 5, mean ± s.d.), not significantly different from the 0.5 expected when glucose is the sole fuel that is completely oxidized. Our results provide a cross-validation of both techniques. Comparison of CMRglc with VTCA is in agreement with a metabolic coupling between the TCA cycle and glycolysis under normal physiologic conditions.

scholarly journals Diffusion MRI Anisotropy in the Cerebral Cortex is Determined by Unmyelinated Tissue Features

2021 ◽  
Author(s):  
Colin Reveley ◽  
Frank Q Ye ◽  
Rogier B Mars ◽  
David A Leopold
Keyword(s):  
Cerebral Cortex ◽  
Gray Matter ◽  
Ex Vivo ◽  
High Signal ◽  
Water Molecules ◽  
Nissl Staining ◽  
Tissue Properties ◽  
Marmoset Monkey ◽  
Cellular Substructure ◽  
The Brain

The diffusion of water molecules through the brain is constrained by tissue and cellular substructure, which imposes an anisotropy that can be measured through diffusion magnetic resonance imaging (dMRI). In the white matter, myelinated axons strongly shape diffusion anisotropy; however, in gray matter the determinants of dMRI signals remain poorly understood. Here we investigated the histological tissue properties underlying dMRI anisotropy and diffusivity in the cerebral cortex of the marmoset monkey. We acquired whole brain ex vivo dMRI data designed for high signal-to-noise at ultra-high (150μm) resolution. We compared the MRI to myelin- and Nissl-stained histological sections obtained from the scanned brain. We found that dMRI anisotropy corresponds most strongly not with cortical myelin content, but rather with the microscale anisotropy of tissue features, most notably those unmyelinated features highlighted by Nissl staining. The results suggest that dMRI anisotropy in gray matter derives from the organization of unmyelinated neurites, which are known to be affected by neurodegenerative diseases.

scholarly journals Imaging and modelling of poly(3-hydroxybutyrate) synthesis in Paracoccus denitrificans

2021 ◽  
Author(s):  
Sergio Bordel ◽  
Rob J. M. van Spanning ◽  
Fernando Santos-Beneit
Keyword(s):  
Exponential Growth ◽  
Laser Scanning ◽  
Paracoccus Denitrificans ◽  
Tca Cycle ◽  
Metabolic Model ◽  
Acetyl Coa ◽  
Granule Formation ◽  
The Tca Cycle ◽  
A Genome ◽  
Phb Production

Abstract Poly(3-hydroxybutyrate) (PHB) granule formation in Paracoccus denitrificans Pd1222 was investigated by laser scanning confocal microscopy (LSCM) and gas chromatography analysis. Cells that had been starved for 2 days were free of PHB granules but resynthesized them within 30 minutes of growth in fresh medium with succinate. In most cases, the granules were distributed randomly, although in some cases they appeared in a more organized pattern. The rates of growth and PHB accumulation were analyzed within the frame of a Genome-Scale Metabolic Model (GSMM) containing 781 metabolic genes, 1403 reactions and 1503 metabolites. The model was used to obtain quantitative predictions of biomass yields and PHB synthesis during aerobic growth on succinate as sole carbon and energy sources. The results revealed an initial fast stage of PHB accumulation, during which all of the acetyl-CoA originating from succinate was diverted to PHB production. The next stage was characterized by a tenfold lower PHB production rate and the simultaneous onset of exponential growth, during which acetyl-CoA was predominantly drained into the TCA cycle. Previous research has shown that PHB accumulation correlates with cytosolic acetyl-CoA concentration. It has also been shown that PHB accumulation is not transcriptionally regulated. Our results are consistent with the mentioned findings and suggest that, in absence of cell growth, most of the cellular acetyl-CoA is channeled to PHB synthesis, while during exponential growth, it is drained to the TCA cycle, causing a reduction of the cytosolic acetyl-CoA pool and a concomitant decrease of the synthesis of acetoacetyl-CoA (the precursor of PHB synthesis).

scholarly journals Region-specific RNA m 6 A methylation represents a new layer of control in the gene regulatory network in the mouse brain

Open Biology ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 170166 ◽  
Author(s):  
Mengqi Chang ◽  
Hongyi Lv ◽  
Weilong Zhang ◽  
Chunhui Ma ◽  
Xue He ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Gene Regulatory Network ◽  
Mouse Brain ◽  
Site Selection ◽  
Regulatory Network ◽  
Methylation Site ◽  
Rna Methylation ◽  
Target Mrnas ◽  
Gene Regulatory ◽  
The Brain

N 6 -methyladenosine (m 6 A) is the most abundant epitranscriptomic mark found on mRNA and has important roles in various physiological processes. Despite the relatively high m 6 A levels in the brain, its potential functions in the brain remain largely unexplored. We performed a transcriptome-wide methylation analysis using the mouse brain to depict its region-specific methylation profile. RNA methylation levels in mouse cerebellum are generally higher than those in the cerebral cortex. Heterogeneity of RNA methylation exists across different brain regions and different types of neural cells including the mRNAs to be methylated, their methylation levels and methylation site selection. Common and region-specific methylation have different preferences for methylation site selection and thereby different impacts on their biological functions. In addition, high methylation levels of fragile X mental retardation protein (FMRP) target mRNAs suggest that m 6 A methylation is likely to be used for selective recognition of target mRNAs by FMRP in the synapse. Overall, we provide a region-specific map of RNA m 6 A methylation and characterize the distinct features of specific and common methylation in mouse cerebellum and cerebral cortex. Our results imply that RNA m 6 A methylation is a newly identified element in the region-specific gene regulatory network in the mouse brain.

scholarly journals Severe Spinal Cord Injury in Rats Induces Chronic Changes in the Spinal Cord and Cerebral Cortex Metabolism, Adjusted by Thiamine That Improves Locomotor Performance

2021 ◽  
Vol 14 ◽  
Author(s):  
Alexandra Boyko ◽  
Polina Tsepkova ◽  
Vasily Aleshin ◽  
Artem Artiukhov ◽  
Garik Mkrtchyan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cerebral Cortex ◽  
Vitamin B1 ◽  
Tca Cycle ◽  
Locomotor Recovery ◽  
Cord Injury ◽  
Recovery Treatment ◽  
Protective Strategies ◽  
The Brain

Our study aims at developing knowledge-based strategies minimizing chronic changes in the brain after severe spinal cord injury (SCI). The SCI-induced long-term metabolic alterations and their reactivity to treatments shortly after the injury are characterized in rats. Eight weeks after severe SCI, significant mitochondrial lesions outside the injured area are demonstrated in the spinal cord and cerebral cortex. Among the six tested enzymes essential for the TCA cycle and amino acid metabolism, mitochondrial 2-oxoglutarate dehydrogenase complex (OGDHC) is the most affected one. SCI downregulates this complex by 90% in the spinal cord and 30% in the cerebral cortex. This is associated with the tissue-specific changes in other enzymes of the OGDHC network. Single administrations of a pro-activator (thiamine, or vitamin B1, 1.2 mmol/kg) or a synthetic pro-inhibitor (triethyl glutaryl phosphonate, TEGP, 0.02 mmol/kg) of OGDHC within 15–20 h after SCI are tested as protective strategies. The biochemical and physiological assessments 8 weeks after SCI reveal that thiamine, but not TEGP, alleviates the SCI-induced perturbations in the rat brain metabolism, accompanied by the decreased expression of (acetyl)p53, increased expression of sirtuin 5 and an 18% improvement in the locomotor recovery. Treatment of the non-operated rats with the OGDHC pro-inhibitor TEGP increases the p53 acetylation in the brain, approaching the brain metabolic profiles to those after SCI. Our data testify to an important contribution of the OGDHC regulation to the chronic consequences of SCI and their control by p53 and sirtuin 5.

scholarly journals Differences in the molecular structure of the blood-brain barrier in the cerebral cortex and white matter: an in silico, in vitro, and ex vivo study

2016 ◽  
Vol 310 (11) ◽  
pp. H1702-H1714 ◽  
Author(s):  
Ádám Nyúl-Tóth ◽  
Maria Suciu ◽  
Judit Molnár ◽  
Csilla Fazakas ◽  
János Haskó ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cerebral Cortex ◽  
White Matter ◽  
Blood Brain Barrier ◽  
In Silico ◽  
Grey Matter ◽  
Ex Vivo ◽  
Cortical Grey Matter ◽  
The Brain

The blood-brain barrier (BBB) is the main interface controlling molecular and cellular traffic between the central nervous system (CNS) and the periphery. It consists of cerebral endothelial cells (CECs) interconnected by continuous tight junctions, and closely associated pericytes and astrocytes. Different parts of the CNS have diverse functions and structures and may be subject of different pathologies, in which the BBB is actively involved. It is largely unknown, however, what are the cellular and molecular differences of the BBB in different regions of the brain. Using in silico, in vitro, and ex vivo techniques we compared the expression of BBB-associated genes and proteins (i.e., markers of CECs, brain pericytes, and astrocytes) in the cortical grey matter and white matter. In silico human database analysis (obtained from recalculated data of the Allen Brain Atlas), qPCR, Western blot, and immunofluorescence studies on porcine and mouse brain tissue indicated an increased expression of glial fibrillary acidic protein in astrocytes in the white matter compared with the grey matter. We have also found increased expression of genes of the junctional complex of CECs (occludin, claudin-5, and α-catenin) in the white matter compared with the cerebral cortex. Accordingly, occludin, claudin-5, and α-catenin proteins showed increased expression in CECs of the white matter compared with endothelial cells of the cortical grey matter. In parallel, barrier properties of white matter CECs were superior as well. These differences might be important in the pathogenesis of diseases differently affecting distinct regions of the brain.

scholarly journals Imaging and modelling of poly(3-hydroxybutyrate) synthesis in Paracoccus denitrificans

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergio Bordel ◽  
Rob J. M. van Spanning ◽  
Fernando Santos-Beneit
Keyword(s):  
Exponential Growth ◽  
Laser Scanning ◽  
Paracoccus Denitrificans ◽  
Tca Cycle ◽  
Metabolic Model ◽  
Acetyl Coa ◽  
Granule Formation ◽  
The Tca Cycle ◽  
A Genome ◽  
Phb Production

AbstractPoly(3-hydroxybutyrate) (PHB) granule formation in Paracoccus denitrificans Pd1222 was investigated by laser scanning confocal microscopy (LSCM) and gas chromatography analysis. Cells that had been starved for 2 days were free of PHB granules but resynthesized them within 30 min of growth in fresh medium with succinate. In most cases, the granules were distributed randomly, although in some cases they appeared in a more organized pattern. The rates of growth and PHB accumulation were analyzed within the frame of a Genome-Scale Metabolic Model (GSMM) containing 781 metabolic genes, 1403 reactions and 1503 metabolites. The model was used to obtain quantitative predictions of biomass yields and PHB synthesis during aerobic growth on succinate as sole carbon and energy sources. The results revealed an initial fast stage of PHB accumulation, during which all of the acetyl-CoA originating from succinate was diverted to PHB production. The next stage was characterized by a tenfold lower PHB production rate and the simultaneous onset of exponential growth, during which acetyl-CoA was predominantly drained into the TCA cycle. Previous research has shown that PHB accumulation correlates with cytosolic acetyl-CoA concentration. It has also been shown that PHB accumulation is not transcriptionally regulated. Our results are consistent with the mentioned findings and suggest that, in absence of cell growth, most of the cellular acetyl-CoA is channeled to PHB synthesis, while during exponential growth, it is drained to the TCA cycle, causing a reduction of the cytosolic acetyl-CoA pool and a concomitant decrease of the synthesis of acetoacetyl-CoA (the precursor of PHB synthesis).

scholarly journals Metabolic changes in brain slices over time: a multiplatform metabolomics approach

2020 ◽  
Author(s):  
Carolina Gonzalez-Riano ◽  
Silvia Tapia-González ◽  
Gertrudis Perea ◽  
Candela González-Arias ◽  
Javier DeFelipe ◽  
...  
Keyword(s):  
Brain Slice ◽  
Ex Vivo ◽  
Brain Slices ◽  
Tca Cycle ◽  
Electrophysiological Recording ◽  
Slice Preparation ◽  
Experimental Conditions ◽  
The Status ◽  
The Brain ◽  
Brain Slice Preparation

ABSTRACTBrain slice preparations are widely used for research in neuroscience. However, a high-quality preparation is essential and there is no consensus regarding stable parameters that can be used to define the status of the brain slice preparation after its collection at different time points. Thus, it is critical to establish the best experimental conditions for ex-vivo studies using brain slices for electrophysiological recording. In this study, we used a multiplatform (LC-MS and GC-MS) untargeted metabolomics-based approach to shed light on the metabolome and lipidome changes induced by the brain slice preparation process. We have found significant modifications in the levels of 300 compounds, including several lipid classes and their derivatives, as well as metabolites involved in the GABAergic pathway and the TCA cycle. All these preparation-dependent changes in the brain biochemistry should be taken into consideration for future studies to facilitate non-biased interpretations of the experimental results.

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