Browsing by Author "Piccardo, Pedro"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Allelic Origin of Protease-Sensitive and Protease-Resistant Prion Protein Isoforms in Gerstmann-Sträussler-Scheinker Disease with the P102L Mutation
    (Public Library of Science, 2012) Monaco, Salvatore; Fiorini, Michele; Farinazzo, Alessia; Ferrari, Sergio; Gelati, Matteo; Piccardo, Pedro; Zanusso, Gianluigi; Ghetti, Bernardino; Pathology and Laboratory Medicine, School of Medicine
    Gerstmann-Sträussler-Scheinker (GSS) disease is a dominantly inherited prion disease associated with point mutations in the Prion Protein gene. The most frequent mutation associated with GSS involves a proline-to-leucine substitution at residue 102 of the prion protein, and is characterized by marked variability at clinical, pathological and molecular levels. Previous investigations of GSS P102L have shown that disease-associated pathological prion protein, or PrP(Sc), consists of two main conformers, which under exogenous proteolysis generates a core fragment of 21 kDa and an internal fragment of 8 kDa. Both conformers are detected in subjects with spongiform degeneration, whereas only the 8 kDa fragment is recovered in cases lacking spongiosis. Several studies have reported an exclusive derivation of protease-resistant PrP(Sc) isoforms from the mutated allele; however, more recently, the propagation of protease-resistant wild-type PrP(Sc) has been described. Here we analyze the molecular and pathological phenotype of six GSS P102L cases characterized by the presence of 21 and 8 kDa PrP fragments and two subjects with only the 8 kDa PrP fragment. Using sensitive protein separation techniques and Western blots with antibodies differentially recognizing wild-type and mutant PrP we observed a range of PrP(Sc) allelic conformers, either resistant or sensitive to protease treatment in all investigated subjects. Additionally, tissue deposition of protease-sensitive wild-type PrP(Sc) molecules was seen by conventional PrP immunohistochemistry and paraffin-embedded tissue blot. Our findings enlarge the spectrum of conformational allelic PrP(Sc) quasispecies propagating in GSS P102L thus providing a molecular support to the spectrum of disease phenotypes, and, in addition, impact the diagnostic role of PrP immunohistochemistry in prion diseases.
  • Thumbnail Image
    Item
    Early-onset Dementia with Lewy Bodies
    (Wiley, 2004-04) Takao, Masaki; Ghetti, Bernardino; Yoshida, Hirotaka; Piccardo, Pedro; Narain, Yolanda; Murrell, Jill R.; Vidal, Ruben; Glazier, Bradley S.; Jakes, Ross; Tsutsui, Miho; Grazia Spillantini, Maria; Crowther, R. Anthony; Goedert, Michel; Koto, Atsuo; Pathology and Laboratory Medicine, School of Medicine
    The clinical and neuropathological characteristics of an atypical form of dementia with Lewy bodies (DLB) are described. The proband experienced difficulties in her school performance at 13 years of age. Neurological examination revealed cognitive dysfunction, dysarthria, parkinsonism and myoclonus. By age 14 years, the symptoms had worsened markedly and the proband died at age 15 years. On neuropathological examination, the brain was severely atrophic. Numerous intracytoplasmic and intraneuritic Lewy bodies, as well as Lewy neurites, were present throughout the cerebral cortex and subcortical nuclel; vacuolar changes were seen in the upper layers of the neocortex and severe neuronal loss and gliosis were evident in the cerebral cortex and substantia nigra. Lewy bodies and Lewy neurites were strongly immunoreactive for alpha-synuclein and ubiquitin. Lewy bodies were composed of filamentous and granular material and isolated filaments were decorated by alpha-synuclein antibodies. Immunohistochemistry for tau or beta-amyloid yielded negative results. The etiology of this atypical form of DLB is unknown, since there was no family history and since sequencing of the exonic regions of alpha-Synuclein, beta-Synuclein, Synphilin-1, Parkin, Ubiquitin C-terminal hydrolase L1 and Neurofilament-M failed to reveal a pathogenic mutation. This study provides further evidence of the clinical and pathological heterogeneity of DLB.
  • Thumbnail Image
    Item
    Endogenous proteolytic cleavage of normal and disease-associated isoforms of the human prion protein in neural and non-neural tissues
    (Elsevier, 1998) Jiménez-Huete, Adolfo; Lievens, Patricia M. J.; Vidal, Rubén; Piccardo, Pedro; Ghetti, Bernardino; Tagliavini, Fabrizio; Frangione, Blas; Prelli, Frances; Pathology and Laboratory Medicine, School of Medicine
    We have investigated the proteolytic cleavage of the cellular (PrPC) and pathological (PrPSc) isoforms of the human prion protein (PrP) in normal and prion-affected brains and in tonsils and platelets from neurologically intact individuals. The various PrP species were resolved after deglycosylation according to their electrophoretic mobility, immunoreactivity, Sarkosyl solubility, and, as a novel approach, resistance to endogenous proteases. First, our data show that PrPC proteolysis in brain originates amino-truncated peptides of 21 to 22 and 18 (C1) kd that are similar in different regions and are not modified by the PrP codon 129 genotype, a polymorphism that affects the expression of prion disorders. Second, this proteolytic cleavage of PrPC in brain is blocked by inhibitors of metalloproteases. Third, differences in PrPC proteolysis, and probably in Asn glycosylation and glycosylphosphatidylinositol anchor composition, exist between neural and non-neural tissues. Fourth, protease-resistant PrPSc cores in sporadic Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker F198S disease brains all have an intact C1 cleavage site (Met111-His112), which precludes disruption of a domain associated with toxicity and fibrillogenesis. Fifth, the profile of endogenous proteolytic PrPSc peptides is characteristic of each disorder studied, thus permitting the molecular classification of these prion diseases without the use of proteinase K and even a recognition of PrPSc heterogeneity within type 2 CJD patients having different codon 129 genotype and neuropathological phenotype. This does not exclude the role of additional factors in phenotypic expression; in particular, differences in glycosylation that may be especially relevant in the new variant CJD. Proteolytic processing of PrP may play an important role in the neurotropism and phenotypic expression of prion diseases, but it does not appear to participate in disease susceptibility.
  • Thumbnail Image
    Item
    PET of Brain Prion Protein Amyloid in Gerstmann–Sträussler–Scheinker Disease
    (Wiley, 2010-03) Kepe, Vladimir; Ghetti, Bernardino; Farlow, Martin R.; Bresjanac, Mara; Miller, Karen; Huang, Sung-Cheng; Wong, Koon-Pong; Murrell, Jill R.; Piccardo, Pedro; Epperson, Francine; Repovš, Grega; Smid, Lojze M.; Petrič, Andrej; Siddarth, Prabha; Liu, Jie; Satyamurthy, Nagichettiar; Small, Gary W.; Barrio, Jorge R.; Pathology and Laboratory Medicine, School of Medicine
    In vivo amyloid PET imaging was carried out on six symptomatic and asymptomatic carriers of PRNP mutations associated with the Gerstmann-Sträussler-Scheinker (GSS) disease, a rare familial neurodegenerative brain disorder demonstrating prion amyloid neuropathology, using 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile ([F-18]FDDNP). 2-Deoxy-2-[F-18]fluoro-d-glucose PET ([F-18]FDG) and magnetic resonance imaging (MRI) scans were also performed in each subject. Increased [F-18]FDDNP binding was detectable in cerebellum, neocortex and subcortical areas of all symptomatic gene carriers in close association with the experienced clinical symptoms. Parallel glucose metabolism ([F-18]FDG) reduction was observed in neocortex, basal ganglia and/or thalamus, which supports the close relationship between [F-18]FDDNP binding and neuronal dysfunction. Two asymptomatic gene carriers displayed no cortical [F-18]FDDNP binding, yet progressive [F-18]FDDNP retention in caudate nucleus and thalamus was seen at 1- and 2-year follow-up in the older asymptomatic subject. In vitro FDDNP labeling experiments on brain tissue specimens from deceased GSS subjects not participating in the in vivo studies indicated that in vivo accumulation of [F-18]FDDNP in subcortical structures, neocortices and cerebellum closely related to the distribution of prion protein pathology. These results demonstrate the feasibility of detecting prion protein accumulation in living patients with [F-18]FDDNP PET, and suggest an opportunity for its application to follow disease progression and monitor therapeutic interventions.