Transneuronal Propagation of Pathologic α-Synuclein from the Gut to the Brain Models Parkinson's Disease

Sangjune Kim, Seung Hwan Kwon, Tae In Kam, Nikhil Panicker, Senthilkumar S. Karuppagounder, Saebom Lee, Jun Hee Lee, Wonjoong Richard Kim, Minjee Kook, Catherine A. Foss, Chentian Shen, H. Lee, Subhash Kulkarni, Pankaj J. Pasricha, Gabsang Lee, Martin G. Pomper, Valina L. Dawson, T. M. Dawson, Han Seok Ko

Research output: Contribution to journalArticlepeer-review


Analysis of human pathology led Braak to postulate that α-synuclein (α-syn) pathology could spread from the gut to brain via the vagus nerve. Here, we test this postulate by assessing α-synucleinopathy in the brain in a novel gut-to-brain α-syn transmission mouse model, where pathological α-syn preformed fibrils were injected into the duodenal and pyloric muscularis layer. Spread of pathologic α-syn in brain, as assessed by phosphorylation of serine 129 of α-syn, was observed first in the dorsal motor nucleus, then in caudal portions of the hindbrain, including the locus coeruleus, and much later in basolateral amygdala, dorsal raphe nucleus, and the substantia nigra pars compacta. Moreover, loss of dopaminergic neurons and motor and non-motor symptoms were observed in a similar temporal manner. Truncal vagotomy and α-syn deficiency prevented the gut-to-brain spread of α-synucleinopathy and associated neurodegeneration and behavioral deficits. This study supports the Braak hypothesis in the etiology of idiopathic Parkinson's disease (PD). Gut injection of α-synuclein fibrils converts endogenous α-synuclein to a pathologic species that spreads to the brain. This leads to features of Parkinson's disease, and vagotomy and α-synuclein deficiency prevent the neuropathology and neurobehavioral deficits induced by transmitted pathological α-synuclein.

Original languageEnglish (US)
Pages (from-to)627-641.e7
Issue number4
StatePublished - Aug 21 2019


  • Braak hypothesis
  • Lewy body pathology
  • Parkinson's disease
  • gut to brain transmission
  • motor symptoms
  • neurodegeneration
  • non-motor symptoms
  • pre-formed fibrils
  • vagus nerve
  • α-synuclein

ASJC Scopus subject areas

  • Neuroscience(all)


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