T Helper Cell Activation and Expansion Is Sensitive to Glutaminase Inhibition under Both Hypoxic and Normoxic Conditions

PLoS One. 2016 Jul 28;11(7):e0160291. doi: 10.1371/journal.pone.0160291. eCollection 2016.

Abstract

Immune responses often take place where nutrients and O2 availability are limited. This has an impact on T cell metabolism and influences activation and effector functions. T cell proliferation and expansion are associated with increased consumption of glutamine which is needed in a number of metabolic pathways and regulate various physiological processes. The first step in endogenous glutamine metabolism is reversible and is regulated by glutaminase (GLS1 and GLS2) and glutamine synthase (GLUL). There are two isoforms of GLS1, Kidney type glutaminase (KGA) and Glutaminase C (GAC). The aim of this study is to investigate the expression, localization and role of GLS1 and GLUL in naïve and activated human CD4+ T cells stimulated through the CD3 and CD28 receptors under normoxia and hypoxia. In proliferating cells, GAC was upregulated and KGA was downregulated, and both enzymes were located to the mitochondria irrespective of O2 levels. By contrast GLUL is localized to the cytoplasm and was upregulated under hypoxia. Proliferation was dependent on glutamine consumption, as glutamine deprivation and GLS1 inhibition decreased proliferation and expression of CD25 and CD226, regardless of O2 availability. Again irrespective of O2, GLS1 inhibition decreased the proportion of CCR6 and CXCR3 expressing CD4+ T cells as well as cytokine production. We propose that systemic Th cell activation and expansion might be dependent on glutamine but not O2 availability.

MeSH terms

  • Antigens, CD / metabolism
  • Cell Proliferation
  • Cells, Cultured
  • Cytokines / metabolism
  • Glutaminase / antagonists & inhibitors*
  • Glutamine / administration & dosage
  • Humans
  • Lymphocyte Activation*
  • Mitochondria / enzymology
  • Oxygen / metabolism*
  • Receptors, Chemokine / metabolism
  • T-Lymphocytes, Helper-Inducer / cytology
  • T-Lymphocytes, Helper-Inducer / enzymology*
  • T-Lymphocytes, Helper-Inducer / metabolism

Substances

  • Antigens, CD
  • Cytokines
  • Receptors, Chemokine
  • Glutamine
  • Glutaminase
  • Oxygen

Grant support

This work was supported by University of Oslo (IMB-2016-BSS), Norwegian Research Council (ES 572317) and Throne Holst Stiftelsen (THS-2016-BSS) The funders provided support in the form of salaries for the authors but did not have any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Rheumatech AS, did not contribute to this work financially. Drs. Halvor Holen and Roman Volchenkov contributed in the study design and manuscript preparations personally. The specific roles of these authors are articulated in the ‘author contribution’ section.