Carbimazole is an inhibitor of protein synthesis and protects from neuronal hypoxic damage in vitro.
Oxygen deprivation during ischemic or hemorrhagic stroke results in ATP depletion, loss of ion homeostasis, membrane depolarization, and excitotoxicity. Pharmacologic restoration of cellular energy supply may offer a promising concept to reduce hypoxic cell injury. In this study, we investigated whether carbimazole, a thionamide used to treat hyperthyroidism, reduces neuronal cell damage in oxygen-deprived human SK-N-SH cells or primary cortical neurons. Our results revealed that carbimazole induces an inhibitory phosphorylation of eukaryotic elongation factor 2 (eEF2) that was associated with a marked inhibition of global protein synthesis. Translational inhibition resulted in significant bioenergetic savings, preserving intracellular ATP content in oxygen-deprived neuronal cells and diminishing hypoxic cellular damage. Phosphorylation of eEF2 was mediated by AMP-activated protein kinase and eEF2 kinase. Carbimazole also induced a moderate calcium influx and a transient cAMP increase. To test whether translational inhibition generally diminishes hypoxic cell damage when ATP availability is limiting, the translational repressors cycloheximide and anisomycin were used. Cycloheximide and anisomycin also preserved ATP content in hypoxic SK-N-SH cells and significantly reduced hypoxic neuronal cell damage. Taken together, these data support a causal relation between the pharmacologic inhibition of global protein synthesis and efficient protection of neurons from ischemic damage by preservation of high-energy metabolites in oxygen-deprived cells. Furthermore, our results indicate that carbimazole or other translational inhibitors may be interesting candidates for the development of new organ-protective compounds. Their chemical structure may be used for computer-assisted drug design or screening of compounds to find new agents with the potential to diminish neuronal damage under ATP-limited conditions.
Department of Anesthesiology and Critical Care Medicine (C.L., C.I.S., H.B., M.H.) and Department of General Neurosurgery, Cellular Neurophysiology (T.G.), University Medical Center Freiburg, Freiburg, Germany; and Department of Anatomy and Cell Biology (S.Z., B.H.) and Pharmaceutical Bioinformatics, Institute of Pharmaceutical Sciences (A.E.), Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Cornelius
C
Lehane
Timo
T
Guelzow
Simone
S
Zenker
Anika
A
Erxleben
Christian I
CI
Schwer
Bernd
B
Heimrich
Hartmut
H
Buerkle
Matjaz
M
Humar
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D013956:Antithyroid Agents / Q000494:pharmacology*; D001345:Autoradiography; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002231:Carbimazole / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D015687:Cell Hypoxia / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D054736:Elongation Factor 2 Kinase / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D006801:Humans; D009474:Neurons / Q000187:drug effects*; D010766:Phosphorylation; D011500:Protein Synthesis Inhibitors
D013956:Antithyroid Agents; D011500:Protein Synthesis Inhibitors; D002231:Carbimazole; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; C517689:EEF2K protein, human; D054736:Elongation Factor 2 Kinase; D055372:AMP-Activated Protein Kinases; D020169:Caspases; D002118:Calcium