IMR Press / FBL / Volume 11 / Issue 3 / DOI: 10.2741/2043

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article

Adaptive cellular mechanisms in response to Glutamine-starvation

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1 Department of Surgery - Research Laboratories, Medical University of Vienna
2 Institute of Chemical Technologies and Analysis, Vienna University of Technology, Vienna, Austria
Academic Editor:Jose Mates
Front. Biosci. (Landmark Ed) 2006, 11(3), 3199–3211; https://doi.org/10.2741/2043
Published: 1 September 2006
(This article belongs to the Special Issue Glutamine as a cellular signal)
Abstract

Glutamine (Gln) utilising cells suffer from Gln-starvation during critical illness when plasma Gln levels are decreased. This study investigates whether such cells activate adaptive mechanisms. Monocytic U937 cells were cultured at 0.6 and 0.2 mM Gln for up to four days. Within the first day a decrease of ATP (78% of control), intracellular free Gln (13%), Hsp70 (74%) and proliferation rate (79%) was observed. A prolonged culture at 0.6 mM Gln for additional three days led to a recovery of ATP (97%), Hsp70 (91%) and proliferation (92%). The intracellular free Gln increased only to 41%. At 0.2 mM Gln, however, all levels remained decreased. The activation of the metabolic sensor AMP activated kinase (AMPK) increased immediately in Gln-starving cells but regained normal values only in cells cultured at 0.6 mM. A proteomic analysis identified 23 proteins, which were affected by Gln starvation including metabolic enzymes, proteins involved in synthesis and degradation of RNA and proteins, and stress proteins. These data show that Gln-utilising cells activate adaptive mechanisms in response to Gln-starvation, which enable them to overcome a Gln shortage. At very low Gln concentrations, these adaptive mechanisms are not sufficient to countervail the lack of the amino acid.

Keywords
Glutamine
Amino acid starvation
Starvation response
Stress proteins
Proteomics
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