title: Antimicrobial agent triclosan is a proton ionophore uncoupler of mitochondria in living rat and human mast cells and in primary human keratinocytes.
abstract: Triclosan (TCS) is an antimicrobial used widely in hospitals and personal care products, at ~10 mm. Human skin efficiently absorbs TCS. Mast cells are ubiquitous key players both in physiological processes and in disease, including asthma, cancer and autism. We previously showed that non-cytotoxic levels of TCS inhibit degranulation, the release of histamine and other mediators, from rat basophilic leukemia mast cells (RBL-2H3), and in this study, we replicate this finding in human mast cells (HMC-1.2). Our investigation into the molecular mechanisms underlying this effect led to the discovery that TCS disrupts adenosine triphosphate (ATP) production in RBL-2H3 cells in glucose-free, galactose-containing media (95% confidence interval EC50 = 7.5-9.7 µm), without causing cytotoxicity. Using these same glucose-free conditions, 15 µm TCS dampens RBL-2H3 degranulation by 40%. The same ATP disruption was found with human HMC-1.2 cells (EC50 4.2-13.7 µm), NIH-3 T3 mouse fibroblasts (EC50 4.8-7.4 µm) and primary human keratinocytes (EC50 3.0-4.1 µm) all with no cytotoxicity. TCS increases oxygen consumption rate in RBL-2H3 cells. Known mitochondrial uncouplers (e.g., carbonyl cyanide 3-chlorophenylhydrazone) previously were found to inhibit mast cell function. TCS-methyl, which has a methyl group in place of the TCS ionizable proton, affects neither degranulation nor ATP production at non-cytotoxic doses. Thus, the effects of TCS on mast cell function are due to its proton ionophore structure. In addition, 5 µm TCS inhibits thapsigargin-stimulated degranulation of RBL-2H3 cells: further evidence that TCS disrupts mast cell signaling. Our data indicate that TCS is a mitochondrial uncoupler, and TCS may affect numerous cell types and functions via this mechanism. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Graduate School of Biomedical Science and Engineering, Orono, ME, USA.|Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Weatherly
authors.affiliation: Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
authors.forename: Juyoung
authors.initials: J
authors.lastname: Shim
authors.affiliation: Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
authors.forename: Hina N
authors.initials: HN
authors.lastname: Hashmi
authors.affiliation: Graduate School of Biomedical Science and Engineering, Orono, ME, USA.|Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
authors.forename: Rachel H
authors.initials: RH
authors.lastname: Kennedy
authors.affiliation: Graduate School of Biomedical Science and Engineering, Orono, ME, USA.|Department of Physics and Astronomy, University of Maine, Orono, ME, USA.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Hess
authors.affiliation: Graduate School of Biomedical Science and Engineering, Orono, ME, USA.|Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Gosse
mesh_terms: D000818:Animals; D000891:Anti-Infective Agents, Local / Q000009:adverse effects / Q000494:pharmacology*; D016588:Anticarcinogenic Agents / Q000009:adverse effects / Q000494:pharmacology; D002273:Carcinogens / Q000037:antagonists & inhibitors / Q000633:toxicity; D015550:Cell Degranulation / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008407:Mast Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D041681:NIH 3T3 Cells; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D051381:Rats; D019284:Thapsigargin / Q000037:antagonists & inhibitors / Q000633:toxicity; D014260:Triclosan / Q000009:adverse effects / Q000031:analogs & derivatives / Q000494:pharmacology*; D014475:Uncoupling Agents / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D000891:Anti-Infective Agents, Local; D016588:Anticarcinogenic Agents; D002273:Carcinogens; D014475:Uncoupling Agents; D014260:Triclosan; C502486:methyl triclosan; D019284:Thapsigargin
keywords: HMC-1.2; RBL-2H3; mast cell; mitochondrial uncoupler; triclosan; triclosan-methyl