In Vitro Seeding Activity of Glycoform-Deficient Prions from Variably Protease-Sensitive Prionopathy and Familial CJD Associated with PrPV180I Mutation

Zerui Wang,Mohammed Moudjou,Qingzhong Kong,Yue Lang,Tetsuyuki Kitamoto,Romany Abskharon,Jiafeng Chen,Johnny Dang,Robert B Petersen,Brian S Appleby ,Wen Zou ,Xu Li ,Yong Sun Kim ,Hyoung Gon Lee ,J.p.m Langeveld ,Jing Yuan ,Pingping Shen,Alise Adornato,Jiachun Feng,Jiyan Ma,Li Cui

doi:10.1007/s12035-018-1459-0

Abstract

Both sporadic variably protease-sensitive prionopathy (VPSPr) and familial Creutzfeldt-Jakob disease linked to the prion protein (PrP) V180I mutation (fCJDV180I) have been found to share a unique pathological prion protein (PrPSc) that lacks the protease-resistant PrPSc glycosylated at residue 181 because two of four PrP glycoforms are apparently not converted into the PrPSc from their cellular PrP (PrPC). To investigate the seeding activity of these unique PrPSc molecules, we conducted in vitro prion conversion experiments using serial protein misfolding cyclic amplification (sPMCA) and real-time quaking-induced conversion (RT-QuIC) assays with different PrPC substrates. We observed that the seeding of PrPSc from VPSPr or fCJDV180I in the sPMCA reaction containing normal human or humanized transgenic (Tg) mouse brain homogenates generated PrPSc molecules that unexpectedly exhibited a dominant diglycosylated PrP isoform along with PrP monoglycosylated at residue 181. The efficiency of PrPSc amplification was significantly higher in non-CJDMM than in non-CJDVV human brain homogenate, whereas it was higher in normal TgVV than in TgMM mouse brain homogenate. PrPC from the mixture of normal TgMM and Tg mouse brain expressing PrPV180I mutation (Tg180) but not TgV180I alone was converted into PrPSc by seeding with the VPSPr or fCJDV180I. The RT-QuIC seeding activity of PrPSc from VPSPr and fCJDV180I was significantly lower than that of sCJD. Our results suggest that the formation of glycoform-selective prions may be associated with an unidentified factor in the affected brain and the glycoform-deficiency of PrPSc does not affect the glycoforms of in vitro newly amplified PrPSc.

Highlights

Prions are infectious pathogens that are associated with a group of fatal transmissible spongiform encephalopathies or prion diseases affecting both animals and humans
Zou and co-workers recently discovered that the sporadic variably protease-sensitive prionopathy (VPSPr) along with familial Creutzfeldt-Jakob disease associated with a prion protein (PrP) mutation Val to Ile at residue generates a PrPSc molecule with a unique electrophoretic gel profile and is characterized by the accumulation in the brain of PrPSc that lacks diglycosylated PrPSc and PrPSc monoglycosylated at residue [4,5,6]
At least based on Western blotting, PrP from VPSPr and fCJDV180I seems to have an intact glycoform profile similar to that from normal controls but somehow the diglycosylated PrP and PrP monoglycosylated at residue 181 are not converted into the proteinase K (PK)-resistant PrPSc; only unglycosylated PrP and PrP monoglycosylated at residue 197 are converted into PK-resistant PrPSc [4,5,6]

Summary

Introduction

Prions are infectious pathogens that are associated with a group of fatal transmissible spongiform encephalopathies or prion diseases affecting both animals and humans They are composed mainly of the pathologic scrapie conformers (PrPSc) that originate from their normal cellular prion protein (PrPC) through a conformational transition of the largely α-helical form to predominantly β-sheets by a seed- or template-assisted mechanism [1, 2]. Zou and co-workers recently discovered that the sporadic VPSPr along with familial Creutzfeldt-Jakob disease (fCJD) associated with a PrP mutation Val to Ile at residue (fCJDV180I) generates a PrPSc molecule with a unique electrophoretic gel profile and is characterized by the accumulation in the brain of PrPSc that lacks diglycosylated PrPSc and PrPSc monoglycosylated at residue [4,5,6]. Two subsequent studies revealed that PrPSc from VPSPr patients exhibited very low transmissibility in the first passage of a transmission study in humanized transgenic mice and no transmission was observed at all in the second passage [10, 11]

Methods

Results

Conclusion