Plant-derived human acetylcholinesterase-R provides protection from lethal organophosphate poisoning and its chronic aftermath

FASEB J. 2007 Sep;21(11):2961-9. doi: 10.1096/fj.07-8112com. Epub 2007 May 2.


Therapeutically valuable proteins are often rare and/or unstable in their natural context, calling for production solutions in heterologous systems. A relevant example is that of the stress-induced, normally rare, and naturally unstable "read-through" human acetylcholinesterase variant, AChE-R. AChE-R shares its active site with the synaptic AChE-S variant, which is the target of poisonous organophosphate anticholinesterase insecticides such as the parathion metabolite paraoxon. Inherent AChE-R overproduction under organophosphate intoxication confers both short-term protection (as a bioscavenger) and long-term neuromuscular damages (as a regulator). Here we report the purification, characterization, and testing of human, endoplasmic reticulum-retained AChE-R(ER) produced from plant-optimized cDNA in Nicotiana benthamiana plants. AChE-R(ER) purified to homogeneity showed indistinguishable biochemical properties, with IC50 = 10(-7) M for the organophosphate paraoxon, similar to mammalian cell culture-derived AChE. In vivo titration showed dose-dependent protection by intravenously injected AChE-R(ER) of FVB/N male mice challenged with a lethal dose of paraoxon, with complete elimination of short-term clinical symptoms at near molar equivalence. By 10 days postexposure, AChE-R prophylaxis markedly limited postexposure increases in plasma murine AChE-R levels while minimizing the organophosphate-induced neuromuscular junction dismorphology. Our findings present plant-produced AChE-R(ER) as a bimodal agent, conferring both short- and long-term protection from organophosphate intoxication.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetylcholinesterase / genetics
  • Acetylcholinesterase / isolation & purification
  • Acetylcholinesterase / metabolism*
  • Animals
  • Binding Sites / drug effects
  • Humans
  • Insecticides / toxicity
  • Lethal Dose 50
  • Male
  • Mice
  • Muscle, Skeletal / drug effects
  • Neuromuscular Junction / drug effects*
  • Neuromuscular Junction / metabolism
  • Nicotiana / genetics*
  • Organophosphorus Compounds / toxicity*
  • Paraoxon / toxicity*
  • Plants, Genetically Modified
  • Polyethylene Glycols / chemistry
  • Recombinant Proteins / metabolism
  • Survival Rate
  • Tissue Distribution / drug effects


  • Insecticides
  • Organophosphorus Compounds
  • Recombinant Proteins
  • Polyethylene Glycols
  • Acetylcholinesterase
  • Paraoxon