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Transgenic fatal familial insomnia mice indicate prion infectivity-independent mechanisms of pathogenesis and phenotypic expression of disease.

Bouybayoune I, Mantovani S, Del Gallo F, Bertani I, Restelli E, Comerio L, Tapella L, Baracchi F, Fernández-Borges N, Mangieri M, Bisighini C, Beznoussenko GV, Paladini A, Balducci C, Micotti E, Forloni G, Castilla J, Fiordaliso F, Tagliavini F, Imeri L, Chiesa R - PLoS Pathog. (2015)

Bottom Line: However, the mechanism by which misfolded variants of mutant PrP cause different diseases is not known.No prion infectivity was detectable in Tg(FFI) and Tg(CJD) brains by bioassay or protein misfolding cyclic amplification, indicating that mutant PrP has disease-encoding properties that do not depend on its ability to propagate its misfolded conformation.Tg(FFI) and Tg(CJD) neurons have different patterns of intracellular PrP accumulation associated with distinct morphological abnormalities of the endoplasmic reticulum and Golgi, suggesting that mutation-specific alterations of secretory transport may contribute to the disease phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, IRCCS-"Mario Negri" Institute for Pharmacological Research, Milan, Italy.

ABSTRACT
Fatal familial insomnia (FFI) and a genetic form of Creutzfeldt-Jakob disease (CJD178) are clinically different prion disorders linked to the D178N prion protein (PrP) mutation. The disease phenotype is determined by the 129 M/V polymorphism on the mutant allele, which is thought to influence D178N PrP misfolding, leading to the formation of distinctive prion strains with specific neurotoxic properties. However, the mechanism by which misfolded variants of mutant PrP cause different diseases is not known. We generated transgenic (Tg) mice expressing the mouse PrP homolog of the FFI mutation. These mice synthesize a misfolded form of mutant PrP in their brains and develop a neurological illness with severe sleep disruption, highly reminiscent of FFI and different from that of analogously generated Tg(CJD) mice modeling CJD178. No prion infectivity was detectable in Tg(FFI) and Tg(CJD) brains by bioassay or protein misfolding cyclic amplification, indicating that mutant PrP has disease-encoding properties that do not depend on its ability to propagate its misfolded conformation. Tg(FFI) and Tg(CJD) neurons have different patterns of intracellular PrP accumulation associated with distinct morphological abnormalities of the endoplasmic reticulum and Golgi, suggesting that mutation-specific alterations of secretory transport may contribute to the disease phenotype.

No MeSH data available.


Related in: MedlinePlus

Tg(FFI) mice show cerebral accumulation of protease-resistant PrP.Immunohistochemical detection of PrP using monoclonal antibody 12B2 after PK digestion of sections in a 291-day-old Tg(WT-E1+/-)/Prnp0/0 mouse (A) and in three 338-day-old Tg(FFI-26+/-)/Prnp0/0 mice (B-J). The pattern of PrP deposition was either diffuse, as in the cerebral cortex, hippocampus, thalamus and molecular layer of the cerebellum (B-H), strip-like as in the fimbria (I), or dot-like as in the mesencephalic trigeminal nucleus (J). AD, anterodorsal thalamic nucleus; AV, anteroventral thalamic nucleus; st, stria terminalis; LDDM, laterodorsal thalamic nucleus, dorsomedial part; LDVL laterodorsal thalamic nucleus, ventrolateral part; VL, ventrolateral thalamic nucleus. Scale bars = 1 mm in A, B, C and D, 250 μm in E, F, G and H, and 125 μm in I and J. Results were similar using the 3F4 antibody in Tg(FFI-K5+/-)/Prnp0/0 mice expressing epitopically-tagged mutant PrP.
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ppat.1004796.g009: Tg(FFI) mice show cerebral accumulation of protease-resistant PrP.Immunohistochemical detection of PrP using monoclonal antibody 12B2 after PK digestion of sections in a 291-day-old Tg(WT-E1+/-)/Prnp0/0 mouse (A) and in three 338-day-old Tg(FFI-26+/-)/Prnp0/0 mice (B-J). The pattern of PrP deposition was either diffuse, as in the cerebral cortex, hippocampus, thalamus and molecular layer of the cerebellum (B-H), strip-like as in the fimbria (I), or dot-like as in the mesencephalic trigeminal nucleus (J). AD, anterodorsal thalamic nucleus; AV, anteroventral thalamic nucleus; st, stria terminalis; LDDM, laterodorsal thalamic nucleus, dorsomedial part; LDVL laterodorsal thalamic nucleus, ventrolateral part; VL, ventrolateral thalamic nucleus. Scale bars = 1 mm in A, B, C and D, 250 μm in E, F, G and H, and 125 μm in I and J. Results were similar using the 3F4 antibody in Tg(FFI-K5+/-)/Prnp0/0 mice expressing epitopically-tagged mutant PrP.

Mentions: Neuropathological examination of Tg(FFI) mice showed PrP deposition in the form of diffuse “synaptic-type” immunoreactivity in several regions. These deposits were most prominent in the entorhinal and pyriform cortex, cingulate gyrus, hippocampal formation, thalamus, caudatum, putamen, amygdala and the molecular layer of the cerebellar cortex (Fig 9). Synaptic-type deposits were also present in the other cortical areas and the septum. Dot-like and small round PrP-immunoreactive profiles were seen in several subcortical structures, including the stria terminalis, fimbria and thalamus (Fig 9). Strongly immunoreactive fiber tracts were observed in the stria terminalis and in the stratum lucidum of CA3, corresponding to the hippocampal mossy fibers. Diffuse intraneuronal PrP immunoreactivity was present in the mesencephalic trigeminal nucleus, the vestibular nucleus and the lateral dorsal nucleus of the thalamus. The neurons of the mesencephalic trigeminal nucleus were outlined by dot-like immunoreactive profiles that were also scattered in the neuropil (Fig 9J). The PrP deposits were not fluorescent after thioflavin S staining, indicating that they did not contain amyloid fibrils. No spongiform-like changes were seen. Immunohistochemistry with the anti-GFAP antibody revealed astrogliosis mainly in the hippocampus, external layer of the cerebral cortex, and cerebellum (S3A-S3F Fig). Staining with the anti-Iba1 antibody showed microgliosis mainly in the hippocampus, cerebral cortex and periaqueductal gray (S3G-S3L Fig).


Transgenic fatal familial insomnia mice indicate prion infectivity-independent mechanisms of pathogenesis and phenotypic expression of disease.

Bouybayoune I, Mantovani S, Del Gallo F, Bertani I, Restelli E, Comerio L, Tapella L, Baracchi F, Fernández-Borges N, Mangieri M, Bisighini C, Beznoussenko GV, Paladini A, Balducci C, Micotti E, Forloni G, Castilla J, Fiordaliso F, Tagliavini F, Imeri L, Chiesa R - PLoS Pathog. (2015)

Tg(FFI) mice show cerebral accumulation of protease-resistant PrP.Immunohistochemical detection of PrP using monoclonal antibody 12B2 after PK digestion of sections in a 291-day-old Tg(WT-E1+/-)/Prnp0/0 mouse (A) and in three 338-day-old Tg(FFI-26+/-)/Prnp0/0 mice (B-J). The pattern of PrP deposition was either diffuse, as in the cerebral cortex, hippocampus, thalamus and molecular layer of the cerebellum (B-H), strip-like as in the fimbria (I), or dot-like as in the mesencephalic trigeminal nucleus (J). AD, anterodorsal thalamic nucleus; AV, anteroventral thalamic nucleus; st, stria terminalis; LDDM, laterodorsal thalamic nucleus, dorsomedial part; LDVL laterodorsal thalamic nucleus, ventrolateral part; VL, ventrolateral thalamic nucleus. Scale bars = 1 mm in A, B, C and D, 250 μm in E, F, G and H, and 125 μm in I and J. Results were similar using the 3F4 antibody in Tg(FFI-K5+/-)/Prnp0/0 mice expressing epitopically-tagged mutant PrP.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4400166&req=5

ppat.1004796.g009: Tg(FFI) mice show cerebral accumulation of protease-resistant PrP.Immunohistochemical detection of PrP using monoclonal antibody 12B2 after PK digestion of sections in a 291-day-old Tg(WT-E1+/-)/Prnp0/0 mouse (A) and in three 338-day-old Tg(FFI-26+/-)/Prnp0/0 mice (B-J). The pattern of PrP deposition was either diffuse, as in the cerebral cortex, hippocampus, thalamus and molecular layer of the cerebellum (B-H), strip-like as in the fimbria (I), or dot-like as in the mesencephalic trigeminal nucleus (J). AD, anterodorsal thalamic nucleus; AV, anteroventral thalamic nucleus; st, stria terminalis; LDDM, laterodorsal thalamic nucleus, dorsomedial part; LDVL laterodorsal thalamic nucleus, ventrolateral part; VL, ventrolateral thalamic nucleus. Scale bars = 1 mm in A, B, C and D, 250 μm in E, F, G and H, and 125 μm in I and J. Results were similar using the 3F4 antibody in Tg(FFI-K5+/-)/Prnp0/0 mice expressing epitopically-tagged mutant PrP.
Mentions: Neuropathological examination of Tg(FFI) mice showed PrP deposition in the form of diffuse “synaptic-type” immunoreactivity in several regions. These deposits were most prominent in the entorhinal and pyriform cortex, cingulate gyrus, hippocampal formation, thalamus, caudatum, putamen, amygdala and the molecular layer of the cerebellar cortex (Fig 9). Synaptic-type deposits were also present in the other cortical areas and the septum. Dot-like and small round PrP-immunoreactive profiles were seen in several subcortical structures, including the stria terminalis, fimbria and thalamus (Fig 9). Strongly immunoreactive fiber tracts were observed in the stria terminalis and in the stratum lucidum of CA3, corresponding to the hippocampal mossy fibers. Diffuse intraneuronal PrP immunoreactivity was present in the mesencephalic trigeminal nucleus, the vestibular nucleus and the lateral dorsal nucleus of the thalamus. The neurons of the mesencephalic trigeminal nucleus were outlined by dot-like immunoreactive profiles that were also scattered in the neuropil (Fig 9J). The PrP deposits were not fluorescent after thioflavin S staining, indicating that they did not contain amyloid fibrils. No spongiform-like changes were seen. Immunohistochemistry with the anti-GFAP antibody revealed astrogliosis mainly in the hippocampus, external layer of the cerebral cortex, and cerebellum (S3A-S3F Fig). Staining with the anti-Iba1 antibody showed microgliosis mainly in the hippocampus, cerebral cortex and periaqueductal gray (S3G-S3L Fig).

Bottom Line: However, the mechanism by which misfolded variants of mutant PrP cause different diseases is not known.No prion infectivity was detectable in Tg(FFI) and Tg(CJD) brains by bioassay or protein misfolding cyclic amplification, indicating that mutant PrP has disease-encoding properties that do not depend on its ability to propagate its misfolded conformation.Tg(FFI) and Tg(CJD) neurons have different patterns of intracellular PrP accumulation associated with distinct morphological abnormalities of the endoplasmic reticulum and Golgi, suggesting that mutation-specific alterations of secretory transport may contribute to the disease phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, IRCCS-"Mario Negri" Institute for Pharmacological Research, Milan, Italy.

ABSTRACT
Fatal familial insomnia (FFI) and a genetic form of Creutzfeldt-Jakob disease (CJD178) are clinically different prion disorders linked to the D178N prion protein (PrP) mutation. The disease phenotype is determined by the 129 M/V polymorphism on the mutant allele, which is thought to influence D178N PrP misfolding, leading to the formation of distinctive prion strains with specific neurotoxic properties. However, the mechanism by which misfolded variants of mutant PrP cause different diseases is not known. We generated transgenic (Tg) mice expressing the mouse PrP homolog of the FFI mutation. These mice synthesize a misfolded form of mutant PrP in their brains and develop a neurological illness with severe sleep disruption, highly reminiscent of FFI and different from that of analogously generated Tg(CJD) mice modeling CJD178. No prion infectivity was detectable in Tg(FFI) and Tg(CJD) brains by bioassay or protein misfolding cyclic amplification, indicating that mutant PrP has disease-encoding properties that do not depend on its ability to propagate its misfolded conformation. Tg(FFI) and Tg(CJD) neurons have different patterns of intracellular PrP accumulation associated with distinct morphological abnormalities of the endoplasmic reticulum and Golgi, suggesting that mutation-specific alterations of secretory transport may contribute to the disease phenotype.

No MeSH data available.


Related in: MedlinePlus