An Essential Role for Alzheimer’s-Linked Amyloid Beta Oligomers in Neurodevelopment: Transient Expression of Multiple Proteoforms during Retina Histogenesis

Samuel C. Bartley, Madison T. Proctor, Hongjie Xia, Evelyn Ho, Dong S. Kang, Kristen Schuster, Maíra A. Bicca, Henrique S. Seckler, Kirsten L. Viola, Steven M. Patrie, Neil L. Kelleher, Fernando G. De Mello, William L. Klein*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Human amyloid beta peptide (Aβ) is a brain catabolite that at nanomolar concentrations can form neurotoxic oligomers (AβOs), which are known to accumulate in Alzheimer’s disease. Because a predisposition to form neurotoxins seems surprising, we have investigated whether circumstances might exist where AβO accumulation may in fact be beneficial. Our investigation focused on the embryonic chick retina, which expresses the same Aβ as humans. Using conformationselective antibodies, immunoblots, mass spectrometry, and fluorescence microscopy, we discovered that AβOs are indeed present in the developing retina, where multiple proteoforms are expressed in a highly regulated cell-specific manner. The expression of the AβO proteoforms was selectively associated with transiently expressed phosphorylated Tau (pTau) proteoforms that, like AβOs, are linked to Alzheimer’s disease (AD). To test whether the AβOs were functional in development, embryos were cultured ex ovo and then injected intravitreally with either a beta-site APP-cleaving enzyme 1 (BACE-1) inhibitor or an AβO-selective antibody to prematurely lower the levels of AβOs. The consequence was disrupted histogenesis resulting in dysplasia resembling that seen in various retina pathologies. We suggest the hypothesis that embryonic AβOs are a new type of short-lived peptidergic hormone with a role in neural development. Such a role could help explain why a peptide that manifests deleterious gain-of-function activity when it oligomerizes in the aging brain has been evolutionarily conserved.

Original languageEnglish (US)
Article number2208
JournalInternational journal of molecular sciences
Volume23
Issue number4
DOIs
StatePublished - Feb 1 2022

Keywords

  • Avian embryo cultures
  • Conformation-sensitive antibodies
  • Neurodegeneration
  • Neurodevelopment
  • Tau

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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