The CPT1a inhibitor, etomoxir induces severe oxidative stress at commonly used concentrations

  • Sci Rep. 2018 Apr 19;8(1):6289. doi: 10.1038/s41598-018-24676-6.
Roddy S O'Connor  1  2 ,  Lili Guo  3 ,  Saba Ghassemi  1  2 ,  Nathaniel W Snyder  4 ,  Andrew J Worth  3 ,  Liwei Weng  3 ,  Yoonseok Kam  5 ,  Benjamin Philipson  6 ,  Sophie Trefely  4 ,  Selene Nunez-Cruz  1  2 ,  Ian A Blair  3 ,  Carl H June  1  2 ,  Michael C Milone  7  8
Affiliations
  • 1. Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
  • 2. Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
  • 3. Penn SRP center, Center of Excellence in Environmental Toxicology, and Department of Systems Pharmacology and Translational Therapeutics at the University of Pennsylvania, Philadelphia, PA, USA.
  • 4. A.J. Drexel Autism Institute, Drexel University, Philadelphia, PA, USA.
  • 5. Agilent Technologies Inc, Lexington, MA, USA.
  • 6. University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
  • 7. Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. [email protected].
  • 8. Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. [email protected].
PMID: 29674640 DOI: 10.1038/s41598-018-24676-6
Abstract

Etomoxir (ETO) is a widely used small-molecule inhibitor of fatty acid oxidation (FAO) through its irreversible inhibitory effects on the carnitine palmitoyl-transferase 1a (CPT1a). We used this compound to evaluate the role of fatty acid oxidation in rapidly proliferating T cells following costimulation through the CD28 receptor. We show that ETO has a moderate effect on T cell proliferation with no observable effect on memory differentiation, but a marked effect on oxidative metabolism. We show that this oxidative metabolism is primarily dependent upon glutamine rather than FAO. Using an shRNA approach to reduce CPT1a in T cells, we further demonstrate that the inhibition of oxidative metabolism in T cells by ETO is independent of its effects on FAO at concentrations exceeding 5 μM. Concentrations of ETO above 5 μM induce acute production of ROS with associated evidence of severe oxidative stress in proliferating T cells. In aggregate, these data indicate that ETO lacks specificity for CTP1a above 5 μM, and caution should be used when employing this compound for studies in cells due to its non-specific effects on oxidative metabolism and cellular redox.

Products