UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content

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...

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Autores principales:	Khaggeswar Bheemanapally, Prabhat R. Napit, Mostafa M. H. Ibrahim, Karen P. Briski
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/e4b858a45e394e799d3b44841f5da804
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spelling	oai:doaj.org-article:e4b858a45e394e799d3b44841f5da8042021-12-02T19:06:44ZUHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content10.1038/s41598-021-95646-82045-2322https://doaj.org/article/e4b858a45e394e799d3b44841f5da8042021-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-95646-8https://doaj.org/toc/2045-2322Abstract 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.Khaggeswar BheemanapallyPrabhat R. NapitMostafa M. H. IbrahimKaren P. BriskiNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-11 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Khaggeswar Bheemanapally Prabhat R. Napit Mostafa M. H. Ibrahim Karen P. Briski UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
description	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.
format	article
author	Khaggeswar Bheemanapally Prabhat R. Napit Mostafa M. H. Ibrahim Karen P. Briski
author_facet	Khaggeswar Bheemanapally Prabhat R. Napit Mostafa M. H. Ibrahim Karen P. Briski
author_sort	Khaggeswar Bheemanapally
title	UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
title_short	UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
title_full	UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
title_fullStr	UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
title_full_unstemmed	UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
title_sort	uhplc–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/e4b858a45e394e799d3b44841f5da804
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UHPLC–electrospray ionization–mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content

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