Spongiform Degeneration Research Articles

Gerstmann-Straüssler-Scheinker PRNP P102L-129V mutation

Abstract Neuropathological and biochemical studies in a case of Gerstmann-Straüssler-Scheinker disease bearing the PRNP P102L-129V mutation showed numerous multicentric PrPres in the cerebral cortex, striatum, thalamus and cerebellum, PrPres globular deposits in the anterior and posterior horns of the spinal cord, and multiple granular PrPres deposits in the grey and white matter of the encephalon and spinal cord. Western blots with antiPrPres antibodies revealed several weak bands ranging from 36 to 66 kDa, weak bands of 29 and 24 kDa, a strong band of about 20 kDa, a low band of molecular weight around 15 kDa and a weaker band of about 7 kDa. Spongiform degeneration was absent. Hyper-phosphorylated 3R and 4R tau occurred in dystrophic neurites surrounding PrPres plaques, neuropil threads and, to a lesser degree, in the form of neurofibrillary tangles. Gel electrophoresis of sarkosyl-insoluble fractions and western blotting with anti-phospho-tau antibodies showed a pattern similar to that seen in Alzheimer disease cases run in parallel. Dystrophic neurites in the vicinity of PrPres plaques were enriched in voltage dependent anion channel thus suggesting abnormal accumulation of mitochondria. These changes were associated with increased oxidative damage in neurons and astrocytes, Finally, increased expression of active stress kinases, that have the capacity to phosphorylate tau in vitro, p38 (p-38-P) and SAPK/ JNK (SAPK/JNK-P) was found in cell processes surrounding PrP plaques. Together, these observations provide evidences of mitochondrial abnormalities, and increased oxidative stress damage and oxidative stress responses in GSS bearing the PRNP P102L-129V mutation.

An autopsied case of V180I Creutzfeldt‐Jakob disease presenting with panencephalopathic‐type pathology and a characteristic prion protein type

A 73-year-old Japanese woman showed slowly progressive aphasia, apraxia and dementia. She had no family history of prion disease or dementia. One year later she showed parkinsonism and corticobasal degeneration was initially suspected. On MRI, the left temporal neocortex seemed swollen on T2-weighted images in the initial stage, and a later high-signal intensity region was observed in the cerebral cortex in diffusion-weighted images. The patient developed myoclonus and an akinetic mutism state 15 months and 22 months after onset, respectively. Consecutive electroencephalography revealed no periodic sharp-wave complexes. Prion protein (PrP) gene analysis revealed a valine to isoleucine point mutation at codon 180, and methionine homozygosity at codon 129. This patient's clinical symptoms and disease course were atypical for Creutzfeldt-Jakob disease (CJD), and a stable state with nasal tube-feeding lasted several years. She died of respiratory failure at the age of 81, 102 months after the onset. Autopsy revealed widespread spongiform degeneration with weak synaptic-type PrP deposition, confirming the diagnosis of genetic CJD. Neurons in the cerebral cortex were relatively preserved in number and hypertrophic astrocytosis was generally moderate for such long-term disease, but cerebral white matter showed diffuse severe myelin pallor with tissue rarefaction suggestive of panencephalopatic-type pathology. The cerebellar cortex was relatively well preserved with observation of mild spongiform change in the molecular layer, moderate neuron loss in the Purkinje neuron layer, and scattered small plaque-like PrP deposition. Western blot analysis of protease-resistant PrP showed a characteristic pattern without a diglycoform band. V180I CJD is an interesting form of genetic CJD with regards to the clinicopathologic, molecular and genetic findings.

Spongiform degeneration induced by neuropathogenic murine coronavirus infection

Soluble receptor‐resistant mutant 7 (ssr7) is isolated from a highly neurovirulent mouse hepatitis virus (MHV) JHMV cl‐2 strain (cl‐2). srr7 exhibits lower virulence than its maternal strain in infected mice, which is typically manifested in a longer lifespan. In this study, during the course of infection with srr7, small spongiotic lesions became apparent at 2 days post‐inoculation (pi), they spread out to form spongiform encephalopathy by 8 to 10 days pi. We recently reported that the initial expressions of viral antigens in the brain are detected in the infiltrating monocyte lineage and in ependymal cells. Here, we demonstrate that the next viral spread was observed in glial fibrillary acidic protein‐positive cells or nestin‐positive progenitor cells which take up positions in the subventricular zone (SVZ). From this restricted site of infection in the SVZ, a large area of gliosis extended deep into the brain parenchyma where no viral antigens were detected but vacuolar degeneration started at 48 h pi of the virus. The extremely short incubation period compared with other experimental models of infectious spongiform degeneration in the brain would provide a superior experimental model to investigate the mechanism of spongiotic lesions formation.

An autopsy case of MM2‐cortical + thalamic‐type sporadic Creutzfeldt‐Jakob disease

A 59-year-old Japanese man presented with depressed mood, insomnia, abnormal behavior and dementia. Visual and gait disturbance with ataxia also developed. Diffusion-weighted MRI showed widespread regions of hyperintensity in the bilateral cerebral cortex. The patient died at 62 after a progressive clinical course of 32 months. Myoclonus, periodic sharp-wave complexes on EEG, and akinetic mutism state were not observed. Neuropathologic examination showed widespread cerebral neocortical involvement with both large confluent vacuole-type, alongside fine vacuole-type spongiform changes. Mild spongiform degeneration was observed in the striatum and lateral thalamus. Severe neuron loss with hypertrophic astrocytosis in the medial thalamus and inferior olivary nucleus was present. Cerebral white matter showed diffuse myelin pallor indicating panencephalopathic-type pathology. In the cerebellar cortex, severe Purkinje neuron loss was observed, but no spongiform degeneration in the molecular layer or neuron loss in the granular cell layer. PrP immunostaining showed widespread perivacuolar-type PrP, irregular plaque-like PrP, and synaptic-type PrP depositions in the cerebral neocortex. Mild PrP deposition was observed in the striatum, lateral thalamus and brainstem, whereas PrP deposition was not apparent in the medial thalamus and inferior olivary nucleus. PrP gene analysis showed no mutations, and methionine homozygosity was observed at codon 129. Western blot analysis of protease-resistant PrP showed type 2 PrP pattern. MRI and cerebral neocortical pathology suggested MM2-cortical-type sporadic Creutzfeldt-Jakob disease (sCJD), whereas the clinical course and pathology of the medial thalamus and inferior olivary nucleus suggested MM2-thalamic-type sCJD. We believe this was a combination of MM2-cortical-type and MM2-thalamic-type sCJD, which explains the broad spectrum of MM2-type sCJD findings and symptoms.

Predominant Involvement of the Cerebellum in Guinea Pigs Infected with Bovine Spongiform Encephalopathy (BSE)

This study reports the experimental transmission of bovine spongiform encephalopathy (BSE) to guinea pigs and describes the cerebellar lesions in these animals. Guinea pigs were inoculated intracerebrally with 10% brain homogenates from BSE-affected cattle. These animals were designated as the first passage. Second and third passages were subsequently performed. All guinea pigs developed infection at each passage. The mean incubation period of the first passage was 370 days post-infection (dpi) and this decreased to 307 dpi and 309 dpi for the second and third passages, respectively. Mild to severe spongiform degeneration and gliosis were observed in the cerebral cortex, thalamus and brainstem. In addition, the affected animals had marked pathological changes in the cerebellum characterized by severe cortical atrophy associated with Bergmann radial gliosis of the molecular layer and reduction in the width of the granular cell layer. Immunohistochemically, intense PrP(Sc) deposition and scattered plaque-like deposits were observed in the molecular and granular cell layers. Cerebellar lesions associated with severe atrophy of the cortex have not been reported in animal prion diseases, including in the experimental transmission of PrP(Sc) to small rodents. These lesions were similar to the lesions of human kuru or the VV2 variant of sporadic Creutzfeldt-Jakob disease, although typical kuru plaques or florid plaques were not observed in the affected animals.

Sequence-dependent Prion Protein Misfolding and Neurotoxicity

Prion diseases are neurodegenerative disorders caused by misfolding of the normal prion protein (PrP) into a pathogenic "scrapie" conformation. To better understand the cellular and molecular mechanisms that govern the conformational changes (conversion) of PrP, we compared the dynamics of PrP from mammals susceptible (hamster and mouse) and resistant (rabbit) to prion diseases in transgenic flies. We recently showed that hamster PrP induces spongiform degeneration and accumulates into highly aggregated, scrapie-like conformers in transgenic flies. We show now that rabbit PrP does not induce spongiform degeneration and does not convert into scrapie-like conformers. Surprisingly, mouse PrP induces weak neurodegeneration and accumulates small amounts of scrapie-like conformers. Thus, the expression of three highly conserved mammalian prion proteins in transgenic flies uncovered prominent differences in their conformational dynamics. How these properties are encoded in the amino acid sequence remains to be elucidated.

Probing the Conformation of a Prion Protein Fibril with Hydrogen Exchange

A fragment of the prion protein, PrP(89-143, P101L), bearing a mutation implicated in familial prion disease, forms fibrils that have been shown to induce prion disease when injected intracerebrally into transgenic mice expressing full-length PrP containing the P101L mutation. In this study, we utilize amide hydrogen exchange measurements to probe the organization of the peptide in its fibrillar form. We determined the extent of hydrogen exchange first by tandem proteolysis, liquid chromatography, and mass spectrometry (HXMS) and then by exchange-quenched NMR. Although single amide resolution is afforded by NMR measurements, HXMS is well suited to the study of natural prions because it does not require labeling with NMR active isotopes. Thus, natural prions obtained from infected animals can be compared with model systems such as PrP(89-143, P101L) studied here. In our study, we find two segments of sequence that display a high level of protection from exchange, residues 102-109 and 117-136. In addition, there is a region that displays exchange behavior consistent with the presence of a conformationally heterogeneous turn. We discuss our data with respect to several structural models proposed for infectious PrP aggregates and highlight HXMS as one of the few techniques well suited to studying natural prions.

Marked influence of the route of infection on prion strain apparent phenotype in a scrapie transgenic mouse model

Prion strains yield specific neuropathological features including spongiform degeneration and deposition patterns of pathological prion protein. Their invariant regional distribution, following variations in the infection route, has led to the proposal that prions replicate preferentially in defined neuro-anatomical areas. The molecular mechanisms underlying this apparent strain-specific neuronal tropism are currently unknown. However, a possible explanation may be that prion replication is relatively innocuous, resulting in long-term propagation, thus masking initial regional distribution variations linked to different infection routes. This “low neurotoxicity” may be imputable either to the rodent model used or the prion strain(s) inoculated. To investigate this possibility, we studied prion pathogenesis in a prototypal short-incubation disease model consisting of 127S scrapie strain propagated in tg338 transgenic mice expressing the VRQ allele of ovine PrP. This prion strain derives from a natural sheep scrapie isolate that was serially transmitted to tg338 mice without any obvious transmission barrier and biologically cloned by limiting dilution. We compared the pathology induced by the peripheral or intracerebral inoculation of 127S strain. Surprisingly, we found that the disease greatly differed in clinical signs, abnormal prion protein levels, and neuropathology among the routes of infection. Secondary transmission performed with brain material from mice inoculated either intracranially or intraperitoneally produced similar neuropathological features. These results therefore indicate that the route of infection can strongly influence the apparent phenotype of a scrapie strain.

Leukoencephalopathy Associated with Parvovirus Infection in Cretan Hound Puppies

Leukoencephalopathies in dogs encompass presumably inherited conditions such as leukodystrophies, hypomyelination or spongiform degeneration, but other causes, such as virus infections and toxic or nutritional factors, might also play a contributory role. In this report, we provide evidence of parvovirus infection and replication in the brains of five 6-week-old Cretan hound puppies suffering from a puppy shaker syndrome and leukoencephalopathy. Although these puppies belonged to two different litters, they were closely related, tracing back two generations to the same sire. Histologically, a mild to moderate lymphohistiocytic meningitis, with focal lymphohistiocytic leukoencephalitis in two animals, and a mild to moderate vacuolation with myelin loss, mainly in the white matter of the cerebellum was detected. Vacuolation was also found in the corpus callosum, fimbria hippocampi, mesencephalon, capsula interna, basal ganglia, and hypothalamus. By immunohistology and in situ hybridization, either parvoviral antigen, DNA, mRNA, or replicative intermediate DNA were detected in the cerebellum, hippocampus, periventricular areas, corpus callosum, cerebral cortex, medulla oblongata, and spinal cord. Parvovirus antigen, DNA, and mRNA were present in cells of the outer granular layer of the cerebellum and in periventricular cells, most likely representing spongioblasts, glial cells, neurons, endothelial cells, occasional macrophages, and ependymal cells. Sequencing revealed canine parvovirus type 2 stretches. Thus, an association of parvovirus infection with the leukoencephalopathy seems likely, possibly facilitated by a genetic predisposition due to the mode of inbreeding in this particular dog breed.

Poster Abstracts from the AAAP 20th Annual Meeting and Symposium

Poster Abstracts from the AAAP 20th Annual Meeting and Symposium

Detection of the Abnormal Isoform of the Prion Protein Associated With Chronic Wasting Disease in the Optic Pathways of the Brain and Retina of Rocky Mountain Elk (Cervus elaphus nelsoni)

Eyes and nuclei of the visual pathways in the brain were examined in 30 Rocky Mountain elk (Cervus elaphus nelsoni) representing 3 genotypes of the prion protein gene PRNP (codon 132: MM, ML, or LL). Tissues were examined for the presence of the abnormal isoform of the prion protein associated with chronic wasting disease (PrP(CWD)). Nuclei and axonal tracts from a single section of brain stem at the level of the dorsal motor nucleus of the vagus nerve were scored for intensity and distribution of PrP(CWD) immunoreactivity and degree of spongiform degeneration. This obex scoring ranged from 0 (elk with no PrP(CWD) in the brain stem) to 10 (representing elk in terminal stage of disease). PrP(CWD) was detected in the retina of 16 of 18 (89%) elk with an obex score of > 7. PrP(CWD) was not detected in the retina of the 3 chronic wasting disease-negative elk and 9 elk with an obex score of < 6. PrP(CWD) was found in the nuclei of the visual pathways in the brain before it was found in the retina. Within the retina, PrP(CWD) was first found in the inner plexiform layer, followed by the outer plexiform layer. Intracytoplasmic accumulation of PrP(CWD) was found in a few neurons in the ganglion cell layer in the PRNP 132ML elk but was a prominent feature in the PRNP 132LL elk. Small aggregates of PrP(CWD) were present on the inner surface of the outer limiting membrane in PRNP 132LL elk but not in PRNP 132MM or 132ML elk. This study demonstrates PrP(CWD) accumulation in nuclei of the visual pathways of the brain, followed by PrP(CWD) in the retina.

A novel seven-octapeptide repeat insertion in the prion protein gene (PRNP) in a Dutch pedigree with Gerstmann–Sträussler–Scheinker disease phenotype: comparison with similar cases from the literature

Human prion diseases can be sporadic, inherited or acquired by infection and show considerable phenotypic heterogeneity. We describe the clinical, histopathological and pathological prion protein (PrPSc) characteristics of a Dutch family with a novel 7-octapeptide repeat insertion (7-OPRI) in PRNP, the gene encoding the prion protein (PrP). Clinical features were available in four, neuropathological features in three and biochemical characteristics in two members of this family. The clinical phenotype was characterized by slowly progressive cognitive decline, personality change, lethargy, depression with anxiety and panic attacks, apraxia and a hypokinetic-rigid syndrome. Neuropathological findings consisted of numerous multi- and unicentric amyloid plaques throughout the cerebrum and cerebellum with varying degrees of spongiform degeneration. Genetic and molecular studies were performed in two male family members. One of them was homozygous for valine and the other heterozygous for methionine and valine at codon 129 of PRNP. Sequence analysis identified a novel 168 bp insertion [R2–R2–R2–R2–R3g–R2–R2] in the octapeptide repeat region of PRNP. Both patients carried the mutation on the allele with valine at codon 129. Western blot analysis showed type 1 PrPSc in both patients and detected a smaller ~8 kDa PrPSc fragment in the cerebellum in one patient. The features of this Dutch kindred define an unusual neuropathological phenotype and a novel PRNP haplotype among the previously documented 7-OPRI mutations, further expanding the spectrum of genotype–phenotype correlations in inherited prion diseases.

Clinical, histopathological and genetic studies in a family with fatal familial insomnia

We compared clinical data from two related Chinese patients with fatal familial insomnia (FFI) and collected information about their pedigree. The clinical features in the two cases were similar and included initial progressive insomnia and sympathetic activation, which persisted throughout the clinical course. A total of 135 members of this family, across seven generations, were retrospectively investigated. Eleven family members, including the two FFI cases, were found to have died with similar neurological problems. Analysis of PRNP in 32 family members revealed eleven carrying the D178N allele, including the two FFI patients. Spongiform degeneration in brains was not found, but gliosis was obvious in the thalamus of the two cases at postmortem. Proteinase K-resistant prion protein (PrP) was not found in proband's brain by immunohistochemistry, but observed in some areas of brain for both cases by PrP-specific Western blot. Investigation of the pedigree has led to the identification of an additional 9 family members who had similar clinical symptoms and 9 currently healthy individuals with the D178N mutation.

Live Cell Fluorescence Resonance Energy Transfer Predicts an Altered Molecular Association of Heterologous PrPSc with PrPC

Prion diseases result from the accumulation of a misfolded isoform (PrP(Sc)) of the normal host prion protein (PrP(C)). PrP(Sc) propagates by templating its conformation onto resident PrP(C) to generate new PrP(Sc). Although the nature of the PrP(Sc)-PrP(C) complex is unresolved, certain segments or specific residues are thought to feature critically in its formation. The polymorphic residue 129 is one such site under considerable study. We combined transmission studies with a novel live cell yeast-based fluorescence resonance energy transfer (FRET) system that models the molecular association of PrP in a PrP(Sc)-like state, as a way to explore the role of residue 129 in this process. We show that a reduction in efficiency of prion transmission between donor PrP(Sc) and recipient PrP(C) that are mismatched at residue 129 correlates with a reduction in FRET between PrP-129M and PrP-129V in our yeast model. We further show that this effect depends on the different secondary structure propensities of Met and Val, rather than the specific amino acids. Finally, introduction of the disease-associated P101L mutation (mouse- equivalent) abolished FRET with wild-type mouse PrP, whereas mutant PrP-P101L displayed high FRET with homologous PrP-P101L, as long as residue 129 matched. These studies provide the first evidence for a physical alteration in the molecular association of PrP molecules differing in one or more residues, and they further predict that the different secondary structure propensities of Met and Val define the impaired association observed between PrP(Sc) and PrP(C) mismatched at residue 129.

Multiorgan detection and characterization of protease-resistant prion protein in a case of variant CJD examined in the United States.

BackgroundVariant Creutzfeldt–Jakob disease (vCJD) is a prion disease thought to be acquired by the consumption of prion-contaminated beef products. To date, over 200 cases have been identified around the world, but mainly in the United Kingdom. Three cases have been identified in the United States; however, these subjects were likely exposed to prion infection elsewhere. Here we report on the first of these subjects.Methodology/Principal FindingsNeuropathological and genetic examinations were carried out using standard procedures. We assessed the presence and characteristics of protease-resistant prion protein (PrPres) in brain and 23 other organs and tissues using immunoblots performed directly on total homogenate or following sodium phosphotungstate precipitation to increase PrPres detectability. The brain showed a lack of typical spongiform degeneration and had large plaques, likely stemming from the extensive neuronal loss caused by the long duration (32 months) of the disease. The PrPres found in the brain had the typical characteristics of the PrPres present in vCJD. In addition to the brain and other organs known to be prion positive in vCJD, such as the lymphoreticular system, pituitary and adrenal glands, and gastrointestinal tract, PrPres was also detected for the first time in the dura mater, liver, pancreas, kidney, ovary, uterus, and skin.Conclusions/SignificanceOur results indicate that the number of organs affected in vCJD is greater than previously realized and further underscore the risk of iatrogenic transmission in vCJD.

Proteomic analysis in cerebrospinal fluid of patients with atypical nonketotic hyperglycinemia and pulmonary hypertension – A pilot study

A variant phenotype of nonketotic hyperglycinemia has been described by our group associated with pulmonary hypertension. The aim of this study is to investigate the cerebrospinal fluid proteomes to get an insight into this neurodegenerative process producing leukoencephalopathy with white matter spongiform degeneration. DIGE and MALDI-TOF-TOF analyses were performed to carry out the proteomic study of four patients against three normal controls and one additional control of a classical nonketotic hyperglycinemia. The differential proteomic analysis showed a displacement of some series of spots toward the acidic side. The shifted proteins showed a high degree of carbonylation and increased methionine sulfoxidation was found in cystatin C and in vitamin-D-binding protein. These findings in addition to the increase of serum malondialdehyde concentration provide evidence of an oxidative stress in the patients under study, which is probably systemic rather than mainly confined to the CNS. The similarities of our findings with those found in other neurodegenerative diseases suggest that oxidative damage is commonly involved in these pathologies. DIGE technology improves the 2-D PAGE differential analysis and it is suitable in proteomic studies with a small number of cases.

Role of GFAP in morphological retention and distribution of reactive astrocytes induced by scrapie encephalopathy in mice

We have previously demonstrated that mutant mice bearing astrocytes deficient in glial fibrillary acidic protein (GFAP) exhibited typical spongiform degeneration and prion plaque deposition. However, it remains to be determined whether there are astrocyte-specific alterations in the reactive response of astrocytes. Herein, we analyzed morphological features of Gfap − / − reactive astrocytes. Light microscopic morphometry of mutant reactive astrocytes revealed reduced outlined cell area and shorter distances among expanded cell space but with larger nuclei. Electron microscopy revealed mutant cells containing very few and sparse glial filaments as well as abnormal cytoarchitecture of reactive astrocytic processes. Furthermore, paired cell formation appeared frequently. The results suggest that GFAP is necessary for morphological retention and distribution of reactive astrocytes during prion disease, and that there is a GFAP-dependent function of glial filaments in reactive astrocytes.

Regulation of GABAA and Glutamate Receptor Expression, Synaptic Facilitation and Long-Term Potentiation in the Hippocampus of Prion Mutant Mice

BackgroundPrionopathies are characterized by spongiform brain degeneration, myoclonia, dementia, and periodic electroencephalographic (EEG) disturbances. The hallmark of prioniopathies is the presence of an abnormal conformational isoform (PrPsc) of the natural cellular prion protein (PrPc) encoded by the Prnp gene. Although several roles have been attributed to PrPc, its putative functions in neuronal excitability are unknown. Although early studies of the behavior of Prnp knockout mice described minor changes, later studies report altered behavior. To date, most functional PrPc studies on synaptic plasticity have been performed in vitro. To our knowledge, only one electrophysiological study has been performed in vivo in anesthetized mice, by Curtis and coworkers. They reported no significant differences in paired-pulse facilitation or LTP in the CA1 region after Schaffer collateral/commissural pathway stimulation.Methodology/Principal FindingsHere we explore the role of PrPc expression in neurotransmission and neural excitability using wild-type, Prnp −/− and PrPc-overexpressing mice (Tg20 strain). By correlating histopathology with electrophysiology in living behaving mice, we demonstrate that both Prnp −/− mice but, more relevantly Tg20 mice show increased susceptibility to KA, leading to significant cell death in the hippocampus. This finding correlates with enhanced synaptic facilitation in paired-pulse experiments and hippocampal LTP in living behaving mutant mice. Gene expression profiling using Illumina™ microarrays and Ingenuity pathways analysis showed that 129 genes involved in canonical pathways such as Ubiquitination or Neurotransmission were co-regulated in Prnp −/− and Tg20 mice. Lastly, RT-qPCR of neurotransmission-related genes indicated that subunits of GABAA and AMPA-kainate receptors are co-regulated in both Prnp −/− and Tg20 mice.Conclusions/SignificancePresent results demonstrate that PrPc is necessary for the proper homeostatic functioning of hippocampal circuits, because of its relationships with GABAA and AMPA-Kainate neurotransmission. New PrPc functions have recently been described, which point to PrPc as a target for putative therapies in Alzheimer's disease. However, our results indicate that a “gain of function” strategy in Alzheimer's disease, or a “loss of function” in prionopathies, may impair PrPc function, with devastating effects. In conclusion, we believe that present data should be taken into account in the development of future therapies.

Codistribution of Amyloid β Plaques and Spongiform Degeneration in Familial Creutzfeldt-Jakob Disease With the E200K-129M Haplotype

Dominantly inherited Creutzfeldt-Jakob disease (CJD) represents 5% to 15% of all CJD cases. The E200K mutation in the prion protein (PrP) gene (PRNP) is the most frequent cause of familial CJD. Coexistent amyloid beta (Abeta) plaques have been reported in some transmissible spongiform encephalopathies but to date have not been reported in familial CJD with the E200K mutation. To characterize a family with CJD in which Abeta plaques codistribute with spongiform degeneration. Clinicopathologic and molecular study of a family with CJD with the E200K-129M haplotype. Alzheimer disease research center. Two generations of a family. Clinical, biochemical, and neuropathologic observations in 2 generations of a family. In this kindred, 3 autopsied cases showed pathologic changes typical for the E200K-129M haplotype, including spongiform degeneration, gliosis, neuronal loss, and PrP deposition. Moreover, 2 of these cases (ages 57 and 63 years) showed numerous Abeta plaques codistributed with spongiform degeneration. APOE genotyping in 2 cases revealed that Abeta plaques were present in the APOE epsilon4 carrier but not in the APOE epsilon4 noncarrier. Two additional cases exhibited incomplete penetrance, as they had no clinical evidence of CJD at death after age 80 years but had affected siblings and children. To our knowledge, this is the first description of Abeta plaques in familial CJD with the E200K mutation. The codistribution of plaques and CJD-associated changes suggests that PrP plays a central role in Abeta formation and that Abeta pathology and prion disease likely in fluence each other. The kindred described herein provides support that PrP(E200K) may result in increased Abeta deposition.

Defective autophagy in neurons and astrocytes from mice deficient in PI(3,5)P2

Mutations affecting the conversion of PI3P to the signaling lipid PI(3,5)P2 result in spongiform degeneration of mouse brain and are associated with the human disorders Charcot–Marie–Tooth disease and amyotrophic lateral sclerosis (ALS). We now report accumulation of the proteins LC3-II, p62 and LAMP-2 in neurons and astrocytes of mice with mutations in two components of the PI(3,5)P2 regulatory complex, Fig4 and Vac14. Cytoplasmic inclusion bodies containing p62 and ubiquinated proteins are present in regions of the mutant brain that undergo degeneration. Co-localization of p62 and LAMP-2 in affected cells indicates that formation or recycling of the autolysosome is impaired. These results establish a role for PI(3,5)P2 in autophagy in the mammalian central nervous system (CNS) and demonstrate that mutations affecting PI(3,5)P2 can contribute to inclusion body disease.