S100A9-Driven Amyloid-Neuroinflammatory Cascade in Traumatic Brain Injury as a Precursor State for Alzheimer’s Disease

Research output: Contribution to journalArticle


Pro-inflammatory and amyloidogenic S100A9 protein is an important contributor to Alzheimer’s disease (AD) pathology. Traumatic brain injury (TBI) is viewed as a precursor state for AD. Here we have shown that S100A9-driven amyloid-neuroinflammatory cascade was initiated in TBI and may serve as a mechanistic link between TBI and AD. By analyzing the TBI and AD human brain tissues, we demonstrated that in post-TBI tissues S100A9, produced by neurons and microglia, becomes drastically abundant compared to Aβ and contributes to both precursor-plaque formation and intracellular amyloid oligomerization. Conditions implicated in TBI, such as elevated S100A9 concentration, acidification and fever, provide strong positive feedback for S100A9 nucleation-dependent amyloid formation and delay in its proteinase clearance. Consequently, both intracellular and extracellular S100A9 oligomerization correlated with TBI secondary neuronal loss. Common morphology of TBI and AD plaques indicated their similar initiation around multiple aggregation centers. Importantly, in AD and TBI we found S100A9 plaques without Aβ. S100A9 and Aβ plaque pathology was significantly advanced in AD cases with TBI history at earlier age, signifying TBI as a risk factor. These new findings highlight the detrimental consequences of prolonged post-TBI neuroinflammation, which can sustain S100A9-driven amyloid-neurodegenerative cascade as a specific mechanism leading to AD development.


  • Chao Wang
  • Igor A. Iashchishyn
  • Jonathan Pansieri
  • Sofie Nyström
  • Oxana Klementieva
  • John Kara
  • Istvan Horvath
  • Roman Moskalenko
  • Reza Rofougaran
  • Gunnar Gouras
  • Gabor G. Kovacs
  • S. K. Shankar
  • Ludmilla A. Morozova-Roche
External organisations
  • Umeå University
  • Linköping University
  • Medical University of Vienna
  • Sumy State University
  • National Institute of Mental Health and Neurosciences, Bangalore
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Neurosciences
Original languageEnglish
Article number12836
JournalScientific Reports
Issue number1
Publication statusPublished - 2018
Publication categoryResearch