| 1. |
- Aguilar-Calvo, Patricia, et al.
(författare)
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Shortening heparan sulfate chains prolongs survival and reduces parenchymal plaques in prion disease caused by mobile, ADAM10-cleaved prions
- 2020
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Ingår i: Acta Neuropathologica. - : SPRINGER. - 0001-6322 .- 1432-0533. ; 139:3, s. 527-546
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Tidskriftsartikel (refereegranskat)abstract
- Cofactors are essential for driving recombinant prion protein into pathogenic conformers. Polyanions promote prion aggregation in vitro, yet the cofactors that modulate prion assembly in vivo remain largely unknown. Here we report that the endogenous glycosaminoglycan, heparan sulfate (HS), impacts prion propagation kinetics and deposition sites in the brain. Exostosin-1 haploinsufficient (Ext1(+/-)) mice, which produce short HS chains, show a prolonged survival and a redistribution of plaques from the parenchyma to vessels when infected with fibrillar prions, and a modest delay when infected with subfibrillar prions. Notably, the fibrillar, plaque-forming prions are composed of ADAM10-cleaved prion protein lacking a glycosylphosphatidylinositol anchor, indicating that these prions are mobile and assemble extracellularly. By analyzing the prion-bound HS using liquid chromatography-mass spectrometry (LC-MS), we identified the disaccharide signature of HS differentially bound to fibrillar compared to subfibrillar prions, and found approximately 20-fold more HS bound to the fibrils. Finally, LC-MS of prion-bound HS from human patients with familial and sporadic prion disease also showed distinct HS signatures and higher HS levels associated with fibrillar prions. This study provides the first in vivo evidence of an endogenous cofactor that accelerates prion disease progression and enhances parenchymal deposition of ADAM10-cleaved, mobile prions.
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| 2. |
- Liu, He, et al.
(författare)
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Distinct conformers of amyloid beta accumulate in the neocortex of patients with rapidly progressive Alzheimers disease
- 2021
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Ingår i: Journal of Biological Chemistry. - : Elsevier. - 0021-9258 .- 1083-351X. ; 297:5
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid beta (A beta) deposition in the neocortex is a major hallmark of Alzheimers disease (AD), but the extent of deposition does not readily explain phenotypic diversity and rate of disease progression. The prion strain-like model of disease heterogeneity suggests the existence of different conformers of A beta. We explored this paradigm using conformation-dependent immunoassay (CDI) for A beta and conformation-sensitive luminescent conjugated oligothiophenes (LCOs) in AD cases with variable progression rates. Mapping the A beta conformations in the frontal, occipital, and temporal regions in 20 AD patients with CDI revealed extensive interindividual and anatomical diversity in the structural organization of A beta with the most significant differences in the temporal cortex of rapidly progressive AD. The fluorescence emission spectra collected in situ from A beta plaques in the same regions demonstrated considerable diversity of spectral characteristics of two LCOs-quatroformylthiophene acetic acid and heptaformylthiophene acetic acid. Heptaformylthiophene acetic acid detected a wider range of A beta deposits, and both LCOs revealed distinct spectral attributes of diffuse and cored plaques in the temporal cortex of rapidly and slowly progressive AD and less frequent and discernible differences in the frontal and occipital cortex. These and CDI findings indicate a major conformational diversity of A beta accumulating in the neocortex, with the most notable differences in temporal cortex of cases with shorter disease duration, and implicate distinct A beta conformers (strains) in the rapid progression of AD.
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