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Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells

Methods that rapidly decrease fat in steatotic hepatocytes may be helpful to recover severely fatty livers for transplantation. Defatting kinetics are highly dependent upon the extracellular medium composition; however, the pathways involved are poorly understood. Steatosis was induced in human hepa...

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Autores principales: Yarmush, Gabriel, Santos, Lucas, Yarmush, Joshua, Koundinyan, Srivathsan, Saleem, Mubasher, Nativ, Nir I., Schloss, Rene S., Yarmush, Martin L., Maguire, Timothy J., Berthiaume, Francois
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812330/
https://www.ncbi.nlm.nih.gov/pubmed/26742084
http://dx.doi.org/10.3390/metabo6010001
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author Yarmush, Gabriel
Santos, Lucas
Yarmush, Joshua
Koundinyan, Srivathsan
Saleem, Mubasher
Nativ, Nir I.
Schloss, Rene S.
Yarmush, Martin L.
Maguire, Timothy J.
Berthiaume, Francois
author_facet Yarmush, Gabriel
Santos, Lucas
Yarmush, Joshua
Koundinyan, Srivathsan
Saleem, Mubasher
Nativ, Nir I.
Schloss, Rene S.
Yarmush, Martin L.
Maguire, Timothy J.
Berthiaume, Francois
author_sort Yarmush, Gabriel
collection PubMed
description Methods that rapidly decrease fat in steatotic hepatocytes may be helpful to recover severely fatty livers for transplantation. Defatting kinetics are highly dependent upon the extracellular medium composition; however, the pathways involved are poorly understood. Steatosis was induced in human hepatoma cells (HepG2) by exposure to high levels of free fatty acids, followed by defatting using plain medium containing no fatty acids, or medium supplemented with a cocktail of defatting agents previously described before. We measured the levels of 28 extracellular metabolites and intracellular triglyceride, and fed the data into a steady-state mass balance model to estimate strictly intracellular fluxes. We found that during defatting, triglyceride content decreased, while beta-oxidation, the tricarboxylic acid cycle, and the urea cycle increased. These fluxes were augmented by defatting agents, and even more so by hyperoxic conditions. In all defatting conditions, the rate of extracellular glucose uptake/release was very small compared to the internal supply from glycogenolysis, and glycolysis remained highly active. Thus, in steatotic HepG2 cells, glycolysis and fatty acid oxidation may co-exist. Together, these pathways generate reducing equivalents that are supplied to mitochondrial oxidative phosphorylation.
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spelling pubmed-48123302016-04-06 Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells Yarmush, Gabriel Santos, Lucas Yarmush, Joshua Koundinyan, Srivathsan Saleem, Mubasher Nativ, Nir I. Schloss, Rene S. Yarmush, Martin L. Maguire, Timothy J. Berthiaume, Francois Metabolites Article Methods that rapidly decrease fat in steatotic hepatocytes may be helpful to recover severely fatty livers for transplantation. Defatting kinetics are highly dependent upon the extracellular medium composition; however, the pathways involved are poorly understood. Steatosis was induced in human hepatoma cells (HepG2) by exposure to high levels of free fatty acids, followed by defatting using plain medium containing no fatty acids, or medium supplemented with a cocktail of defatting agents previously described before. We measured the levels of 28 extracellular metabolites and intracellular triglyceride, and fed the data into a steady-state mass balance model to estimate strictly intracellular fluxes. We found that during defatting, triglyceride content decreased, while beta-oxidation, the tricarboxylic acid cycle, and the urea cycle increased. These fluxes were augmented by defatting agents, and even more so by hyperoxic conditions. In all defatting conditions, the rate of extracellular glucose uptake/release was very small compared to the internal supply from glycogenolysis, and glycolysis remained highly active. Thus, in steatotic HepG2 cells, glycolysis and fatty acid oxidation may co-exist. Together, these pathways generate reducing equivalents that are supplied to mitochondrial oxidative phosphorylation. MDPI 2016-01-04 /pmc/articles/PMC4812330/ /pubmed/26742084 http://dx.doi.org/10.3390/metabo6010001 Text en © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Yarmush, Gabriel
Santos, Lucas
Yarmush, Joshua
Koundinyan, Srivathsan
Saleem, Mubasher
Nativ, Nir I.
Schloss, Rene S.
Yarmush, Martin L.
Maguire, Timothy J.
Berthiaume, Francois
Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells
title Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells
title_full Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells
title_fullStr Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells
title_full_unstemmed Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells
title_short Metabolic Flux Distribution during Defatting of Steatotic Human Hepatoma (HepG2) Cells
title_sort metabolic flux distribution during defatting of steatotic human hepatoma (hepg2) cells
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812330/
https://www.ncbi.nlm.nih.gov/pubmed/26742084
http://dx.doi.org/10.3390/metabo6010001
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