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Unraveling the complex metabolic nature of astrocytes.

Bouzier-Sore AK, Pellerin L - Front Cell Neurosci (2013)

Bottom Line: Moreover, this unusual metabolic feature was found to be modulated by glutamatergic activity constituting the initial step of the neurometabolic coupling mechanism.Several approaches, including biochemical measurements in cultured cells, genetic screening, dynamic cell imaging, nuclear magnetic resonance spectroscopy and mathematical modeling, have provided further insights into the intrinsic characteristics giving rise to these key features of astrocytes.This review will provide an account of the different results obtained over several decades that contributed to unravel the complex metabolic nature of astrocytes that make this cell type unique.

View Article: PubMed Central - PubMed

Affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS/Université Bordeaux Segalen Bordeaux, France.

ABSTRACT
Since the initial description of astrocytes by neuroanatomists of the nineteenth century, a critical metabolic role for these cells has been suggested in the central nervous system. Nonetheless, it took several technological and conceptual advances over many years before we could start to understand how they fulfill such a role. One of the important and early recognized metabolic function of astrocytes concerns the reuptake and recycling of the neurotransmitter glutamate. But the description of this initial property will be followed by several others including an implication in the supply of energetic substrates to neurons. Indeed, despite the fact that like most eukaryotic non-proliferative cells, astrocytes rely on oxidative metabolism for energy production, they exhibit a prominent aerobic glycolysis capacity. Moreover, this unusual metabolic feature was found to be modulated by glutamatergic activity constituting the initial step of the neurometabolic coupling mechanism. Several approaches, including biochemical measurements in cultured cells, genetic screening, dynamic cell imaging, nuclear magnetic resonance spectroscopy and mathematical modeling, have provided further insights into the intrinsic characteristics giving rise to these key features of astrocytes. This review will provide an account of the different results obtained over several decades that contributed to unravel the complex metabolic nature of astrocytes that make this cell type unique.

No MeSH data available.


Typical high resolution at the magic angle spinning (HRMAS) 1H-NMR spectrum of rat brain biopsy after [3-13C]lactate perfusion. Protons of the methyl group of lactate are detected (black arrows), centered at 1.32 ppm. The doublet is coming from the homonuclear spin coupling (JH-H = 7 Hz, red arrows). When a 13C is located on lactate carbon 3, then a doublet of doublet is appearing (13C satellites of H3 lactate), due to the heteronuclear spin coupling (JH-C = 128 Hz, horizontal blue arrows).
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Figure 2: Typical high resolution at the magic angle spinning (HRMAS) 1H-NMR spectrum of rat brain biopsy after [3-13C]lactate perfusion. Protons of the methyl group of lactate are detected (black arrows), centered at 1.32 ppm. The doublet is coming from the homonuclear spin coupling (JH-H = 7 Hz, red arrows). When a 13C is located on lactate carbon 3, then a doublet of doublet is appearing (13C satellites of H3 lactate), due to the heteronuclear spin coupling (JH-C = 128 Hz, horizontal blue arrows).

Mentions: As indicated in the first part of this review, astrocytes exhibit a clear aerobic glycolysis. NMR spectroscopy is particularly suitable to estimate the rate of glycolysis in astrocytes, by measuring the rate of lactate formation. 1H-NMR spectroscopy allows detecting on the same spectrum, the 13C-labeled lactate synthetized from glycolysis of the administered 13C-labeled glucose, and also, the unlabeled lactate coming from unlabeled precursors. Indeed, as shown in Figure 2, on carbon 3 of the unlabeled lactate, the protons of the methyl group will give a doublet at 1.32 ppm, rising from their homonuclear coupling (1H/1H) with the neighbor 1H linked to carbon 2 (Figure 2, in red). On the other hand, the [3-13C] lactate will lead to two doublets, at 1.21 and 1.43 ppm due to the heteronuclear coupling (1H/13C, different coupling value J = 128 Hz).


Unraveling the complex metabolic nature of astrocytes.

Bouzier-Sore AK, Pellerin L - Front Cell Neurosci (2013)

Typical high resolution at the magic angle spinning (HRMAS) 1H-NMR spectrum of rat brain biopsy after [3-13C]lactate perfusion. Protons of the methyl group of lactate are detected (black arrows), centered at 1.32 ppm. The doublet is coming from the homonuclear spin coupling (JH-H = 7 Hz, red arrows). When a 13C is located on lactate carbon 3, then a doublet of doublet is appearing (13C satellites of H3 lactate), due to the heteronuclear spin coupling (JH-C = 128 Hz, horizontal blue arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3795301&req=5

Figure 2: Typical high resolution at the magic angle spinning (HRMAS) 1H-NMR spectrum of rat brain biopsy after [3-13C]lactate perfusion. Protons of the methyl group of lactate are detected (black arrows), centered at 1.32 ppm. The doublet is coming from the homonuclear spin coupling (JH-H = 7 Hz, red arrows). When a 13C is located on lactate carbon 3, then a doublet of doublet is appearing (13C satellites of H3 lactate), due to the heteronuclear spin coupling (JH-C = 128 Hz, horizontal blue arrows).
Mentions: As indicated in the first part of this review, astrocytes exhibit a clear aerobic glycolysis. NMR spectroscopy is particularly suitable to estimate the rate of glycolysis in astrocytes, by measuring the rate of lactate formation. 1H-NMR spectroscopy allows detecting on the same spectrum, the 13C-labeled lactate synthetized from glycolysis of the administered 13C-labeled glucose, and also, the unlabeled lactate coming from unlabeled precursors. Indeed, as shown in Figure 2, on carbon 3 of the unlabeled lactate, the protons of the methyl group will give a doublet at 1.32 ppm, rising from their homonuclear coupling (1H/1H) with the neighbor 1H linked to carbon 2 (Figure 2, in red). On the other hand, the [3-13C] lactate will lead to two doublets, at 1.21 and 1.43 ppm due to the heteronuclear coupling (1H/13C, different coupling value J = 128 Hz).

Bottom Line: Moreover, this unusual metabolic feature was found to be modulated by glutamatergic activity constituting the initial step of the neurometabolic coupling mechanism.Several approaches, including biochemical measurements in cultured cells, genetic screening, dynamic cell imaging, nuclear magnetic resonance spectroscopy and mathematical modeling, have provided further insights into the intrinsic characteristics giving rise to these key features of astrocytes.This review will provide an account of the different results obtained over several decades that contributed to unravel the complex metabolic nature of astrocytes that make this cell type unique.

View Article: PubMed Central - PubMed

Affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS/Université Bordeaux Segalen Bordeaux, France.

ABSTRACT
Since the initial description of astrocytes by neuroanatomists of the nineteenth century, a critical metabolic role for these cells has been suggested in the central nervous system. Nonetheless, it took several technological and conceptual advances over many years before we could start to understand how they fulfill such a role. One of the important and early recognized metabolic function of astrocytes concerns the reuptake and recycling of the neurotransmitter glutamate. But the description of this initial property will be followed by several others including an implication in the supply of energetic substrates to neurons. Indeed, despite the fact that like most eukaryotic non-proliferative cells, astrocytes rely on oxidative metabolism for energy production, they exhibit a prominent aerobic glycolysis capacity. Moreover, this unusual metabolic feature was found to be modulated by glutamatergic activity constituting the initial step of the neurometabolic coupling mechanism. Several approaches, including biochemical measurements in cultured cells, genetic screening, dynamic cell imaging, nuclear magnetic resonance spectroscopy and mathematical modeling, have provided further insights into the intrinsic characteristics giving rise to these key features of astrocytes. This review will provide an account of the different results obtained over several decades that contributed to unravel the complex metabolic nature of astrocytes that make this cell type unique.

No MeSH data available.