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Pierluigi Gambetti

Publications and source records attributed to Pierluigi Gambetti.

At least 37 records · Page 2Linked to original sources
PubMed2004

Fatal familial insomnia: the first account in a family of Chinese descent.

BACKGROUND: Fatal familial insomnia (FFI) is an autosomal dominant disease linked to a mutation in the prion protein gene. Fatal familial insomnia is characterized by sleep disturbance and loss of neurons, with gliosis in the thalamic nuclei. OBJECTIVE: To describe the clinical, neurophysiological, radiological, and neuropathological data in a Chinese family with FFI. SETTING: Tertiary referral university hospital setting. PATIENTS: Patient 1 was a 36-year-old man who presented with insomnia and myoclonus. In the subsequent 9 months, he developed ataxia and dementia, followed by death. Patient 2 was the aunt of patient 1, and presented at the age of 47 years with insomnia, myoclonus, and dementia; her condition declined during a 12-month period. Genetic analysis was performed, followed by neuropathological and biochemical analysis of the disease-associated form of the prion protein PrPSc on the postmortem brain specimen. RESULTS: Molecular analysis demonstrated an aspartic acid to asparagine mutation at codon 178 and homozygosity for methionine at codon 129. Both patients showed severe neuronal loss and prominent gliosis in the thalamus and brainstem involvement, with evidence of astrogliosis in the inferior olivary nucleus. Patient 1 also had neuronal loss and astrogliosis in the region of the superior colliculus and in the periaqueductal region. PrPSc was detected on Western blot analysis, and had a wide distribution. The strongest signals were present in the amygdala, hypothalamus, caudate, parahippocampal gyrus, periaqueductal gray matter, and mediodorsal thalamus. CONCLUSIONS: To our knowledge, this is the first report of FFI in a family of Chinese descent. This supports the worldwide distribution of FFI, and despite differences in genetic background, the clinical and pathological findings are similar to those found in white patients with FFI.

Adult↗
PubMed2004

Expression of excitatory amino acid transporter-1 (EAAT-1) in brain macrophages and microglia of patients with prion diseases.

The mechanisms of neuronal apoptosis in prion diseases are unclear. Experimental studies suggest that it may result from 2 associated mechanisms: glutamate-mediated excitotoxicity and oxidative stress. Recent studies showed that activated macrophages/microglia (AMM) express excitatory amino acid transporters (EAATs) in HIV infection, suggesting that they may play a neuroprotective role by clearing extra-cellular glutamate and producing anti-oxidant glutathione. In order to test this hypothesis in prion diseases, samples from cerebral cortex, striatum, thalamus, and cerebellum from 14 patients with Creutzfeldt-Jakob disease (8 sporadic, 2 familial, 2 iatrogenic, and 2 variant), and 4 with fatal familial insomnia (3 homozygous Met/Met at codon 129 of the PRNP gene, 1 heterozygous Met/Val), and 3 controls were immunostained for EAAT-1, GFAP, HLA-DR, CD68, IL-1, caspase 3, and PrP. In prion diseases, EAAT-1 immunopositivity was found in affected areas. Only AMM, interstitial, perivascular, perineuronal (sometimes around apoptotic neurons), or close to reactive astrocytes, expressed EAAT-1. Astrocyte EAAT-1 expression was scarcely detectable in controls and was not detected in prion disease cases. The proportion of AMM expressing EAAT-1 did not correlate with the severity of neuronal apoptosis, spongiosis, astrocytosis, microgliosis, or PrP deposition, but only with disease duration. Occasional EAAT-1 expressing AMM were found in patients with short survival, whereas diffuse EAAT-1 expression by AMM was observed in cases with long survival (24 to 33 months) that most often were heterozygous for Met/Val at codon 129 of the PRNP gene. Our findings suggest that AMM may develop a partial neuroprotective function in long-lasting prion diseases, although it does not seem to efficiently prevent neurological and neuropathological deterioration. Whether this neuroprotective function of microglia is the cause or the effect of longer survival needs to be clarified.

Adult↗
PubMed2004

Targeting prion amyloid deposits in vivo.

The diagnosis of prion diseases in humans is challenging due to a lack of specific and sensitive non-invasive tests. Many forms of human prion disease including variant Creutzfeldt-Jakob disease (vCJD), Gerstmann-Sträussler-Scheinker (GSS) syndrome, and 10% of sporadic CJD cases are associated with amyloid deposition. Several positron emission tomography (PET) ligands have recently been developed to directly image beta-amyloid associated with Alzheimer disease. One of them, methoxy-X04, is a fluorescent derivative of Congo red with high binding affinity toward amyloid fibrils and good blood-brain barrier permeability. Using methoxy-X04, we investigated whether amyloid-targeting ligands can be also employed for direct imaging of amyloid deposits associated with some prion diseases. Such a method could potentially become a novel diagnostic approach for these conditions. Studies were performed on MB mice infected with the 87V mouse-adapted scrapie strain. Labeling of PrP amyloid plaques in brains of presymptomatic and symptomatic mice was demonstrated using in vivo transcranial two-photon microscopy after systemic administration of methoxy-X04. During real-time imaging, PrP amyloid deposits could be clearly distinguished 15 min after intravenous administration of methoxy-X04. The ligand showed rapid clearance from brain areas that did not contain amyloid deposits. PrP amyloid deposits could also be detected by direct application of methoxy-X04 on cerebellar sections from GSS patients. These results suggest that methoxy-X04 or similar derivatives could be used as PET imaging agents to improve the diagnosis of human prion diseases associated with amyloid deposition.

Alkenes↗
PubMed2004

Chronic wasting disease and potential transmission to humans.

Chronic wasting disease (CWD) of deer and elk is endemic in a tri-corner area of Colorado, Wyoming, and Nebraska, and new foci of CWD have been detected in other parts of the United States. Although detection in some areas may be related to increased surveillance, introduction of CWD due to translocation or natural migration of animals may account for some new foci of infection. Increasing spread of CWD has raised concerns about the potential for increasing human exposure to the CWD agent. The foodborne transmission of bovine spongiform encephalopathy to humans indicates that the species barrier may not completely protect humans from animal prion diseases. Conversion of human prion protein by CWD-associated prions has been demonstrated in an in vitro cell-free experiment, but limited investigations have not identified strong evidence for CWD transmission to humans. More epidemiologic and laboratory studies are needed to monitor the possibility of such transmissions

Animals↗
PubMed2004

Soluble amyloid beta-protein is increased in frontotemporal dementia with tau gene mutations.

The relationship between senile plaques and neurofibrillary tangles, the main pathologic lesions of Alzheimer's disease, is not completely understood. We addressed this issue examining the type and amount of amyloid beta-protein (Abeta) associated with the soluble and insoluble tissue fractions in the frontal cortex of 8 cases with frontotemporal dementia with parkinsonism caused by mutations of the Tau gene (FTDP-17), in which the intracellular accumulation of polymerised tau is definitely the primary cause of neurodegeneration. As control, we examined 7 cases with frontotemporal dementia lacking distinctive histopathology (DLDH) as well as 8 pathologically normal subjects. In all cases the presence of Abeta deposits was ruled out using immunocytochemistry on sections adjacent to those used for biochemical analysis. ELISA analysis showed a 2.7 and 2.1 fold (p < 0.01) increase of soluble Abeta42 and Abeta40 in FTDP-17, compared to normal and DLDH brains, both of which had comparable levels of Abeta species. Furthermore, the immunoreactivity of the intracellular Abeta42 was significantly increased in cortical neurons of subjects affected with FTDP-17. The results demonstrate that the aggregation of tau protein produces an accumulation of Abeta, which, however, does not reach the critical concentration needed for Abetaplaques formation.

Aged↗
PubMed2003

Identification of novel proteinase K-resistant C-terminal fragments of PrP in Creutzfeldt-Jakob disease.

The central event in the pathogenesis of prion diseases, a group of fatal, transmissible neurodegenerative disorders including Creutzfeldt-Jakob disease (CJD) in humans, is the conversion of the normal or cellular prion protein (PrPC) into the abnormal or scrapie isoform (PrPSc). The basis of the PrPC to PrPSc conversion is thought to involve the diminution of alpha-helical domains accompanied by the increase of beta structures within the PrP molecule. Consequently, treatment of PrPSc with proteinase K (PK) generates a large PK-resistant C-terminal core fragment termed PrP27-30 that in human prion diseases has a gel mobility of approximately 19-21 kDa for the unglycosylated form, and a ragged N terminus between residues 78 and 103. PrP27-30 is considered the pathogenic and infectious core of PrPSc. Here we report the identification of two novel PK-resistant, but much smaller C-terminal fragments of PrP (PrP-CTF 12/13) in brains of subjects with sporadic CJD. PrP-CTF 12/13, like PrP27-30, derive from both glycosylated as well as unglycosylated forms. The unglycosylated PrPCTF 12/13 migrate at 12 and 13 kDa and have the N terminus at residues 162/167 and 154/156, respectively. Therefore, PrP-CTF12/13 are 64-76 amino acids N-terminally shorter than PrP27-30 and are about half of the size of PrP27-30. PrP-CTF12/13 are likely to originate from a subpopulation of PrPSc distinct from that which generates PrP27-30. The finding of PrP-CTF12/13 in CJD brains widens the heterogeneity of the PK-resistant PrP fragments associated with prion diseases and may provide useful insights toward the understanding of the PrPSc structure and its formation.

Antibodies↗
PubMed2003

Abbreviated incubation times for human prions in mice expressing a chimeric mouse-human prion protein transgene.

Transgenic (Tg) mouse lines that express chimeric mouse-human prion protein (PrP), designated MHu2M, are susceptible to prions from patients with sporadic Creutzfeldt-Jakob disease (sCJD). With the aim of decreasing the incubation time to fewer than 200 days, we constructed transgenes in which one or more of the nine human residues in MHu2M were changed to mouse. The construct with murine residues at positions 165 and 167 was expressed in Tg(MHu2M,M165V,E167Q) mice and resulted in shortening the incubation time to approximately 110 days for prions from sCJD patients. The construct with a murine residue at position 96 resulted in lengthening the incubation time to more than 280 days for sCJD prions. When murine residues 96, 165, and 167 were expressed, the abbreviated incubation times for sCJD prions were abolished. Variant CJD prions showed prolonged incubation times between 300 and 700 days in Tg(MHu2M) mice on first passage and incubation times of approximately 350 days in Tg(MHu2M,M165V,E167Q) mice. On second and third passages of variant CJD prions in Tg(MHu2M) mice, multiple strains of prions were detected based on incubation times and the sizes of the protease-resistant, deglycosylated PrP(Sc) fragments. Our discovery of a previously undescribed chimeric transgene with abbreviated incubation times for sCJD prions should facilitate studies on the prion species barrier and human prion diversity.

Amino Acid Substitution↗
PubMed2003

Hereditary Creutzfeldt-Jakob disease and fatal familial insomnia.

Studies on hereditary CJD and FFI have contributed greatly to the understanding of all forms of prion disease. Most importantly, they have provided strong support for the prion hypothesis [2]. The linkage of pathogenic PRNP mutations to human prion disease strengthens the notion that a change in PrP conformation is a key event that triggers the development of the disease. Although hereditary CJD and FFI account for only 10% of all cases of human prion disease, they provide a unique opportunity for studying disease pathogenesis initiated by perturbation in the PrP structure. An understanding of the events that accompany a change in PrP conformation has far-reaching implications for sCJD (the most common form of the disease) and for sporadic fatal insomnia. A wealth of available evidence indicates that a common pathway in disease pathogenesis may be shared by both the sporadic and the hereditary forms of prion disease, except that the initiating events are stochastic in the former, rather than predetermined by the presence of a germ-line mutation. In addition, investigations of hereditary CJD and FFI have provided plausible mechanisms of phenotypic heterogeneity in prion disease, a phenomenon analogous to the "prion strain" diversity in animal prion disease. Although many other neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis, and Huntington's chorea are fairly homogeneous in disease phenotype, prion disease includes many clinically and pathologically distinct disease entities. In hereditary prion disease, the disease phenotype is likely to be determined by the combined effect of pathogenic mutations, codon 129 polymorphism, and the type of PrPSc. The pathogenic mutations include point mutations that are located mostly in the central and C-terminal region of PrP, and deletion and insertion mutations that are located in the N-terminal region. It is conceivable that these distinct types of mutations may result in differential changes in conformation or stability of PrP. The codon 129 polymorphism plays a twofold role in modulating the disease outcome. On the mutant allele, it determines the basic features of the disease phenotype--as in the case of FFI and CJD178--that result respectively from the coupling of M or V at codon 129 with the D178N mutation. On the normal allele, it may modulate the severity of the phenotype. A PrPSc subtype is encoded by the PRNP haplotype, and subsequently is generated by a conformational conversion process that transforms the cellular isoform to the pathogenic protein. The site for the formation of a specific PrPSc conformer and its accumulation in different brain regions are likely to contribute to the clinical features and pathologic lesions. The phenotypic homogeneity in other neurologic diseases, including Alzheimer's disease, may be due, in part, to the lack of a powerful genetic modifier such as the codon 129 polymorphism in the PrP gene, and the lack of the ability of affected gene products such as PrP to assume multiple protein conformations. Clearly, the remaining issue in the understanding of pathogenesis of prion disease is a detailed and accurate knowledge of the in vivo processes and conditions for the formation of PrPSc that inevitably lead to the development and expression of the disease. This knowledge will enable the development of a rational and effective strategy for therapeutic intervention.

Creutzfeldt-Jakob Syndrome↗
PubMed2003

Familial and sporadic fatal insomnia.

Familial fatal insomnia (FFI)--a hereditary prion disease caused by a mutation at codon 178 of the prion-protein (PrP) gene (PRNP) that leads to a D178N substitution in the protein--and its sporadic form, sporadic fatal insomnia (SFI), have similar disease phenotypes. Both disorders have clinical features of disrupted sleep (loss of sleep spindles and slow-wave sleep and enacted dreams during rapid-eye-movement sleep), autonomic hyperactivation, and motor abnormalities (myoclonus, ataxia, dysarthria, dysphagia, and pyramidal signs). PET shows pronounced thalamic and limbic hypometabolism that becomes more widespread in later stages. Neuropathological assessment reveals severe neuronal loss and astrogliosis of the anterior medial thalamus and inferior olives, with later cerebral cortical and cerebellar involvement. Accumulation of an isoform of protease-resistant PrP fragment in FFI distinct from that found in a familial form of Creutzfeldt-Jakob disease with the same D178N mutation, shows the effect of the polymorphism at codon 129 of PRNP on phenotypic expression and the possibility of distinct prion "strains" with diverse pathological potential. Intriguing clinicopathological correlations in FFI and SFI suggest a role for the thalamolimbic system in the regulation of sleep and other circadian functions.

Amyloid↗
PubMed2003

Sporadic and familial CJD: classification and characterisation.

Prion diseases are unique transmissible neurodegenerative diseases that have diverse phenotypes and can be familial, sporadic, or acquired by infection. Recent findings indicate that the PrP genotype and the PrP(Sc) type have a major influence on the disease phenotype in both sporadic and familial human prion diseases. This review attempts to classify and characterise sporadic and familial Creutzfeldt-Jakob disease (CJD) as a function of these two disease determinants. Based on the genotype at codon 129 on both PRNP alleles, the size of protease resistant PrP(Sc) fragments and disease phenotype, we divide sporadic CJD into six subtypes: sCJDMM1/sCJDMV1, sCJDVV2, sCJDMV2, sCJDMM2, sCJDVV1, and sporadic fatal insomnia (sFI). Familial CJD is classified into many haplotypes based on the PRNP mutation and codon 129 (and other polymorphic codons) on the mutant allele. The clinical and pathological features are summarised for each sporadic CJD subtype and familial CJD haplotype.

Adolescent↗
PubMed2002

Intercellular transfer of the cellular prion protein.

The cellular prion protein (PrP(C)) is a glycosylphosphatidylinositol (GPI)-anchored protein. We investigated whether PrP(C) can move from one cell to another cell in a cell model. Little PrP(C) transfer was detected when a PrP(C) expressing human neuroblastoma cell line was cultured with the human erythroleukemia cells IA lacking PrP(C). Efficient transfer of PrP(C) was detected with the presence of phorbol 12-myristate 13-acetate, an activator of protein kinase C. Maximum PrP(C) transfer was observed when both donor and recipient cells were activated. Furthermore, PrP(C) transfer required the GPI anchor and direct cell to cell contact. However, intercellular protein transfer is not limited to PrP(C), another GPI-anchored protein, CD90, also transfers from the donor cells to acceptor cells after cellular activation. Therefore, this transfer process is GPI-anchor and cellular activation dependent. These findings suggest that the intercellular transfer of GPI-anchored proteins is a regulated process, and may have implications for the pathogenesis of prion disease.

Blotting, Western↗
PubMed2002

A journey through the species barrier.

The species barrier in prion infectivity is believed to reside in the degree of amino acid sequence heterology between the infectious prion protein, PrP(Sc), of the donor and the normal PrP of the host. bring new evidence that distinct PrP(Sc) species or prion strains may have different conformations even when they have identical amino acid sequence and that the conformation of the exogenous prion strain is a determinant of the species barrier in hosts that have identical PrP genotype.

Animals↗
PubMed2002

Spontaneous mutations in the prion protein gene causing transmissible spongiform encephalopathy.

We analyzed the prion protein gene (PRNP) region in patients with transmissible spongiform encephalopathy associated with the PRNP D178N mutation. The results suggest that the D178N chromosomes had independent origins in each affected pedigree or apparently sporadic case. A de novo spontaneous PRNP mutation was observed. We provide evidence that hereditary and apparently sporadic transmissible spongiform encephalopathy cases associated with the D178N mutation result from multiple recurrent mutational events.

Adult↗
PubMed2002

Human prion diseases.

Transmissible spongiform encephalopathy (TSE) is a group of rare, sub-acute, fatal neurodegenerative diseases in humans and animals. TSE includes Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker disease, fatal familial insomnia, and Kuru (a disease confined to the Fore linguistic group, a tribe in Papua-New Guinea). From the onset, it was recognized that some of these spongiform diseases occur in clusters, in an inherited, familial manner. This article describes these diseases, current treatment modalities, and suggests directions for future research.

Adult↗
PubMed2002

Does the prion protein gene 129 codon polymorphism influence sleep? Evidence from a fatal familial insomnia kindred.

OBJECTIVE: Experimental and clinical evidence in prion diseases suggests that the prion protein gene (PRNP) plays a role in regulating sleep. METHODS: Seventeen healthy individuals belonging to a single fatal familial insomnia pedigree, 8 carriers and 9 non-carriers of the PRNP codon 178 mutation, underwent polysomnography and spectral electroencephalographic (EEG) analysis. All were also characterized with regard to the codon 129 polymorphism on both PRNP alleles. RESULTS: PRNP codon 129 polymorphism exhibited influences on sleep-EEG activities. In particular, spindle frequency band power and balance between delta and spindle activity were found to correlate with the genotype of PRNP codon 129, irrespective of the mutation at codon 178. CONCLUSIONS: Our data suggest that PRNP codon 129 polymorphism may also affect sleep in the healthy population and warrant further studies in the general population and other sleep disorders.

Adult↗
PubMed2002

Heterogeneity of normal prion protein in two- dimensional immunoblot: presence of various glycosylated and truncated forms.

The common use of one-dimensional (1-D) immunoblot with a single monoclonal antibody (Mab) engenders the notion that the normal or cellular prion protein (PrP(C) ) comprises few and simple forms. In this study we used two-dimensional (2-D) immunoblot with a panel Mabs to various regions of the prion protein to demonstrate the complexity of the PrP(C) present in human brain. We distinguished over 50 immunoblot spots, each representing a distinct PrP(C) species based on combinations of different molecular weights and isoelectric points (pIs). The PrP(C) heterogeneity is due to the presence of a full-length and two major truncated forms as well as to the diversity of the glycans linked to most of these forms. The two major truncated forms result from distinct cleavage sites located at the N-terminus. In addition, enzymatic removal of sialic acid and lectin binding studies indicate that the glycans linked to the full-length and truncated PrP(C) forms differ in their structure and ratios of the glycoforms. The truncation of PrP(C) and the heterogeneity of the linked glycans may play a role in regulating PrP(C) function. Furthermore, the presence of relatively large quantities of different PrP(C) species may provide additional mechanisms by which the diversity of prion strains could be generated.

Antibodies, Monoclonal↗