Amiodarone alters late endosomes and inhibits SARS coronavirus infection at a post-endosomal level

Am J Respir Cell Mol Biol. 2008 Aug;39(2):142-9. doi: 10.1165/rcmb.2007-0217OC. Epub 2008 Feb 28.


Amiodarone interferes with the endocytic pathway, inhibits proteolysis, and causes the formation of vacuoles, but uptake and intracellular distribution of the drug, origin of vacuoles, and functional consequences of amiodarone accumulation remain unclear. Our objective was to study amiodarone uptake, clarify the origin of vacuoles, and investigate the effect of amiodarone on the life cycle of the coronavirus responsible for the Severe Acute Respiratory Syndrome (SARS), which, to enter cells, relies on the proteolytic cleavage of a viral spike protein by the endosomal proteinase cathepsin L. Using alveolar macrophages, we studied uptake of (125)I-amiodarone and (125)I-B2, an analog lacking the lateral group diethylamino-beta-ethoxy, and analyzed the effects of amiodarone on the distribution of endosomal markers and on the uptake of an acidotropic dye. Furthermore, using Vero cells, we tested the impact of amiodarone on the in vitro spreading of the SARS coronavirus. We found that (1) amiodarone associates with different cell membranes and accumulates in acidic organelles; (2) the diethylamino-beta-ethoxy group is an important determinant of uptake; (3) vacuoles forming upon exposure to amiodarone are enlarged late endosomes; (4) amiodarone inhibits the spreading in vitro of SARS coronavirus; and (5) trypsin cleavage of the viral spike protein before infection, which permits virus entry through the plasma membrane, does not impair amiodarone antiviral activity. We conclude that amiodarone alters late compartments of the endocytic pathway and inhibits SARS coronavirus infection by acting after the transit of the virus through endosomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amiodarone / pharmacokinetics
  • Amiodarone / pharmacology*
  • Animals
  • Antiviral Agents / pharmacokinetics
  • Antiviral Agents / pharmacology*
  • Cathepsin L
  • Cathepsins / metabolism
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Chlorocebus aethiops
  • Cysteine Endopeptidases / metabolism
  • Cytoplasm / drug effects
  • Cytoplasm / metabolism
  • Endosomes / drug effects
  • Endosomes / metabolism*
  • Humans
  • Iodine Isotopes / chemistry
  • Macrophages, Alveolar / drug effects
  • Macrophages, Alveolar / metabolism*
  • Macrophages, Alveolar / virology
  • Membrane Glycoproteins / metabolism
  • SARS Virus / drug effects*
  • SARS Virus / physiology
  • Severe Acute Respiratory Syndrome / drug therapy
  • Severe Acute Respiratory Syndrome / metabolism*
  • Severe Acute Respiratory Syndrome / virology
  • Spike Glycoprotein, Coronavirus
  • Vacuoles / drug effects
  • Vacuoles / metabolism
  • Vero Cells
  • Viral Envelope Proteins / metabolism


  • Antiviral Agents
  • Iodine Isotopes
  • Membrane Glycoproteins
  • Spike Glycoprotein, Coronavirus
  • Viral Envelope Proteins
  • spike glycoprotein, SARS-CoV
  • Cathepsins
  • Cysteine Endopeptidases
  • CTSL protein, human
  • Cathepsin L
  • Amiodarone