Lesion of the olfactory epithelium accelerates prion neuroinvasion and disease onset when prion replication is restricted to neurons

PLoS One. 2015 Mar 30;10(3):e0119863. doi: 10.1371/journal.pone.0119863. eCollection 2015.

Abstract

Natural prion diseases of ruminants are moderately contagious and while the gastrointestinal tract is the primary site of prion agent entry, other mucosae may be entry sites in a subset of infections. In the current study we examined prion neuroinvasion and disease induction following disruption of the olfactory epithelium in the nasal mucosa since this site contains environmentally exposed olfactory sensory neurons that project directly into the central nervous system. Here we provide evidence for accelerated prion neuroinvasion and clinical onset from the olfactory mucosa after disruption and regeneration of the olfactory epithelium and when prion replication is restricted to neurons. In transgenic mice with neuron restricted replication of prions, there was a reduction in survival when the olfactory epithelium was disrupted prior to intranasal inoculation and there was >25% decrease in the prion incubation period. In a second model, the neurotropic DY strain of transmissible mink encephalopathy was not pathogenic in hamsters by the nasal route, but 50% of animals exhibited brain infection and/or disease when the olfactory epithelium was disrupted prior to intranasal inoculation. A time course analysis of prion deposition in the brain following loss of the olfactory epithelium in models of neuron-restricted prion replication suggests that neuroinvasion from the olfactory mucosa is via the olfactory nerve or brain stem associated cranial nerves. We propose that induction of neurogenesis after damage to the olfactory epithelium can lead to prion infection of immature olfactory sensory neurons and accelerate prion spread to the brain.

Publication types

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

MeSH terms

  • Animals
  • Brain Diseases / etiology
  • Brain Diseases / pathology
  • Brain Diseases / physiopathology
  • Cranial Nerves / pathology
  • Cricetinae
  • Disease Models, Animal
  • Mesocricetus
  • Methimazole / toxicity
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Models, Neurological
  • Neurogenesis
  • Olfactory Mucosa / drug effects
  • Olfactory Mucosa / innervation*
  • Olfactory Mucosa / pathology*
  • Olfactory Nerve / pathology
  • Olfactory Receptor Neurons / drug effects
  • Olfactory Receptor Neurons / pathology
  • Olfactory Receptor Neurons / physiology
  • PrPSc Proteins / pathogenicity
  • Prion Diseases / etiology*
  • Prion Diseases / pathology
  • Prion Diseases / physiopathology
  • Prions / pathogenicity*
  • Prions / physiology
  • Rats

Substances

  • PrPSc Proteins
  • Prions
  • Methimazole