2-Chlorohexadecanoic acid induces ER stress and mitochondrial dysfunction in brain microvascular endothelial cells

  • Redox Biol. 2018 May;15:441-451. doi: 10.1016/j.redox.2018.01.003.
Eva Bernhart  1 ,  Nora Kogelnik  2 ,  Jürgen Prasch  3 ,  Benjamin Gottschalk  4 ,  Madeleine Goeritzer  5 ,  Maria Rosa Depaoli  6 ,  Helga Reicher  7 ,  Christoph Nusshold  8 ,  Ioanna Plastira  9 ,  Astrid Hammer  10 ,  Günter Fauler  11 ,  Roland Malli  12 ,  Wolfgang F Graier  13 ,  Ernst Malle  14 ,  Wolfgang Sattler  15
Affiliations
  • 1. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 2. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 3. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 4. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 5. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria; BioTechMed Graz, Austria. Electronic address: [email protected].
  • 6. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 7. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 8. Institute of Physiological Chemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 9. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 10. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Cell Biology, Histology and Embryology, Medical University of Graz, Austria. Electronic address: [email protected].
  • 11. Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Austria. Electronic address: [email protected].
  • 12. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria; BioTechMed Graz, Austria. Electronic address: [email protected].
  • 13. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria; BioTechMed Graz, Austria. Electronic address: [email protected].
  • 14. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria. Electronic address: [email protected].
  • 15. Gottfried Schatz Research Center for Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria; BioTechMed Graz, Austria. Electronic address: [email protected].
PMID: 29413957 DOI: 10.1016/j.redox.2018.01.003
Abstract

Peripheral leukocytes induce blood-brain barrier (BBB) dysfunction through the release of cytotoxic mediators. These include hypochlorous acid (HOCl) that is formed via the myeloperoxidase-H2O2-chloride system of activated phagocytes. HOCl targets the endogenous pool of ether Phospholipids (plasmalogens) generating chlorinated inflammatory mediators like e.g. 2-chlorohexadecanal and its conversion product 2-chlorohexadecanoic acid (2-ClHA). In the cerebrovasculature these compounds inflict damage to brain microvascular endothelial cells (BMVEC) that form the morphological basis of the BBB. To follow subcellular trafficking of 2-ClHA we synthesized a 'clickable' alkyne derivative (2-ClHyA) that phenocopied the biological activity of the parent compound. Confocal and superresolution structured illumination microscopy revealed accumulation of 2-ClHyA in the endoplasmic reticulum (ER) and mitochondria of human BMVEC (hCMEC/D3 cell line). 2-ClHA and its alkyne analogue interfered with protein palmitoylation, induced ER-stress markers, reduced the ER ATP content, and activated transcription and secretion of interleukin (IL)-6 as well as IL-8. 2-ClHA disrupted the mitochondrial membrane potential and induced procaspase-3 and PARP cleavage. The protein kinase R-like ER kinase (PERK) inhibitor GSK2606414 suppressed 2-ClHA-mediated activating transcription factor 4 synthesis and IL-6/8 secretion, but showed no effect on endothelial barrier dysfunction and cleavage of procaspase-3. Our data indicate that 2-ClHA induces potent lipotoxic responses in brain endothelial cells and could have implications in inflammation-induced BBB dysfunction.

Keywords
Apoptosis; Blood-brain barrier; Lipotoxicity; Myeloperoxidase; Neuroinflammation; Structured illumination microscopy.
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