Abundant pyroglutamate-modified ABri and ADan peptides in extracellular and vascular amyloid deposits in familial British and Danish dementias.

Abstract

Familial British and familial Danish dementia (FDD) are progressive neurodegenerative disorders characterized by cerebral deposition of the amyloidogenic peptides ABri and ADan, respectively. These amyloid peptides start with an N-terminal glutamate residue, which can be posttranslationally converted into a pyroglutamate (pGlu) modified form, a mechanism which has been extensively described to be relevant for amyloid-beta (Aβ) peptides in Alzheimer's disease. Like pGlu-Aβ peptides, pGlu-ABri peptides have an increased aggregation propensity and show higher toxicity on human neuroblastoma cells as their nonmodified counterparts. We have generated novel N-terminal specific antibodies detecting the pGlu-modified forms of ABri and ADan peptides. With these antibodies we were able to identify abundant extracellular amyloid plaques, vascular, and parenchymal deposits in human familial British dementia and FDD brain tissue, and in a mouse model for FDD. Double-stainings using C-terminal specific antibodies in human samples revealed that highly aggregated pGlu-ABri and pGlu-ADan peptides are mainly present in plaque cores and central vascular deposits, leading to the assumption that these peptides have seeding properties. Furthermore, in an FDD-mouse model ADan peptides were detected in presynaptic terminals of the hippocampus where they might contribute to impaired synaptic transmission. These similarities of ABri and ADan to Aβ in Alzheimer's disease suggest that the posttranslational pGlu-modification of amyloid peptides might represent a general pathological mechanism leading to increased aggregation and toxicity in these forms of degenerative dementias.

• Authors: Anika Saul, Tammaryn Lashley, Tamas Revesz, Janice Holton, Jorge A Ghiso, Janaky Coomaraswamy, Oliver Wirths
• Journal: Neurobiology of aging (Neurobiol Aging) Vol. 34 Issue 5 Pg. 1416-25 (May 2013) ISSN: 1558-1497 [Electronic] United States
• PMID: 23261769 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• Adaptor Proteins, Signal Transducing
• ITM2B protein, human
• Membrane Glycoproteins
• Pyrrolidonecarboxylic Acid

Topics

• Adaptor Proteins, Signal Transducing
• Adult
• Aged
• Animals
• Blood Vessels (metabolism)
• Dementia (physiopathology)
• Extracellular Fluid (metabolism)
• Female
• Humans
• Male
• Membrane Glycoproteins (metabolism)
• Mice
• Mice, Transgenic
• Pyrrolidonecarboxylic Acid (metabolism)