Misfolded protein in the amygdala is a neuropathologic feature of Alzheimer disease and many other neurodegenerative disorders. We examined extracts from human amygdala (snap-frozen at autopsy) to investigate whether novel and as yet uncharacterized misfolded proteins would be detectable. Polypeptides from the detergentinsoluble, urea-soluble protein fractions of amygdala were interrogated using liquid chromatography-electrospray ionization-tandem mass spectrometry. Among the detergent-insoluble proteins identified in amygdala of demented subjects but not controls were Tau, TDP-43, Aβ, α-synuclein, and ApoE. Additional detergent-insoluble proteins from demented subjects in the high-molecular weight portion of SDS gels included NNT, TNIK, PRKDC (DNA-PK, or DNA-PKcs), ferritin light chain (FTL), AIFM1, SYT11, STX1B, EAA1, COL25A1, M4K4, CLH1, SQSTM, SYNJ1, C3, and C4. In follow-up immunohistochemical experiments, NNT, TNIK, PRKDC, AIFM1, and FTL were observed in inclusion body-like structures in cognitively impaired subjects' amygdalae. Doublelabel immunofluorescence revealed that FTL and phospho-PRKDC immunoreactivity colocalized partially with TDP-43 and/or Tau inclusion bodies. Western blots showed high-molecular weight "smears", particularly for NNT and PRKDC. A preliminary genetic association study indicated that rare NNT, TNIK, and PRKDC gene variants had nominally significant association with Alzheimer-type dementia risk. In summary, novel detergent-insoluble proteins, with evidence of proteinaceous deposits, were found in amygdalae of elderly, cognitively impaired subjects.
|Number of pages||19|
|Journal||Journal of Neuropathology and Experimental Neurology|
|State||Published - Jan 1 2018|
Bibliographical noteFunding Information:
Send correspondence to: Peter T. Nelson, MD, PhD, Division of Neuropa-thology, Department of Pathology, Rm 311, Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY 40536-0230; E-mail: email@example.com The study was supported by NIH grants P30 AG028383, R01 AG042419, R01 AG042475, T32 AG 000242, R21 NS095299 (to J.G.), and VA MERIT award I01 BX002149 (to H.Z.). The Orbitrap mass spectrometer was acquired by NIH Grant S10 RR029127 (to H.Z.).
© 2017 American Association of Neuropathologists, Inc.
ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Clinical Neurology
- Cellular and Molecular Neuroscience