Depleting prion protein using splice-switching small molecules
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE330903 | GEO | 2026/07/09
REPOSITORIES: GEO
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Project description:In vertebrates, the prion protein (PrP, gene name Prnp) is expressed in diverse cell types and tissues, especially in the brain. In the adult brain, PrP contributes to homeostasis. Here, proteins expressed in the adult mouse brain which coimmunoprecipitated with PrP via the Fab antibody D18 were identified by comparison to PrP-specific immunoprecipitates from Prnp knockout brain.
2021-11-02 | PXD024870 | Pride
Project description:Prion disease is caused by misfolding of the prion protein (PrP) into pathogenic self-propagating conformations, leading to rapid onset dementia and death. However, elimination of endogenous PrP can halt prion disease progression. Here, we describe CHARM, a compact, enzyme-free epigenetic editor capable of silencing transcription through programmable targeted DNA methylation. Using a histone H3 tail-Dnmt3l fusion, CHARM recruits and activates the endogenous DNA methyltransferases, thereby reducing transgene size and bystander effects. When delivered to the mouse brain by an adeno-associated viral (AAV) vector, PRNP-targeted CHARM ablates PrP expression across the brain. We temporally limit editor expression by implementing a kinetically-tuned self-silencing approach. CHARM represents a broadly applicable strategy to programmably prevent expression of pathogenic proteins, including those implicated in other neurodegenerative diseases.
2024-05-03 | GSE255987 | GEO
Project description:Aggregation of the prion protein (PrP) and formation of PrP amyloid (APrP) is severe in some Prion diseases. In the dominantly inherited prion protein amyloidosis known as Gerstmann-Sträussler-Scheinker (GSS) disease, plaques made of PrP amyloid are a distinct feature. The TTC to TCC mutation in Prion protein gene (PRNP), resulting in a phenylalanine to serine amino acid substitution at PrP residue 198, causes a severe amyloidosis in a well-studied GSS variant. The neuropathologic phenotype of this neurodegenerative disease is characterized by the presence of numerous extracellular APrP plaques and intracytoplasmic tau neuronal inclusions which are identical to neurofibrillary tangles of Alzheimer disease. Using cryogenic electron microscopy (cryo-EM), we determined for the first time the structures of filaments of human APrP, isolated post-mortem from the brain of a symptomatic PRNP F198S mutation carrier. We report that in GSS (F198S) APrP filaments are composed of dimeric, trimeric and tetrameric left-handed protofilaments with their protomers sharing a common protein fold. The protomers in the cross-β spines consist of sixty-two amino acids and span from glycine 80 to phenylalanine 141, adopting a previously unseen spiral fold with a thicker outer layer and a thinner inner layer. Each protomer comprises nine short β-strands. The β1 and β8 strands as well as the β4 and β9 strands are engaged in a steric zipper. The new data, obtained by Cryo-EM, provide insights into the complexity of the structure of pathogenic PrP, and reveal the difference of PrP’s structure in brain disease versus that of recombinant PrP, highlighting the urgency of extending our knowledge of the structure of the amyloid filaments involved in human neurodegenerative diseases.
2022-07-18 | PXD032402 | Pride
Project description:Human mesenchymal stem cells (hMSC) play an important role in the maintenance of bone and blood. Most protocols rely on their in vitro expansion prior to clinical use. However, several groups including our own have shown that hMSC lose proliferation and differentiation ability with serial passage in culture, limiting their clinical applications. Here we show that targeting prion protein (PrP) by chemical intervention delays this process. When PrP expression was knocked down, cultures showed significant reduction in proliferation and differentiation capacity. In contrast hMSC expanded in the presence of small molecule modulator of PrP expression, 3/689, showed extended lifespan up to 10 population doublings. Upon re-plating cultures contained more than double the number of clonogenic progenitors and showed a 10 fold increase in engraftment levels in bone marrow 5 weeks post-transplant. Human MSC treated with 3/689 showed enhanced protection from DNA damage and enhanced cell cycle progression. Gene expression profiling revealed upregulation of superoxide dismutase 2 in cells treated with 3/689, dependent on PrP expression, and suggests increased scavenging of reactive oxygen species as mechanism of action. These data point to PrP as a good target to delay loss of proliferation and differentiation of hMSC with expansion in culture. Gene expression changes in hMSC expanded in the presence of 10uM small molecule modulator of prion protein 3/689 or DMSO were analysed at passage 2 and passage 8 from 3 separate donors.
2012-01-30 | E-GEOD-31205 | biostudies-arrayexpress
Project description:Cytoplasmic RNA granules have emerged as important elements of posttranscriptional and translational regulation. Stress, germinal and neuronal granules contain RNA-binding proteins capable of self-assembly due to prion-like domains. Hyperassembly mediated by these prion-like domains causes several neurodegenerative diseases. Here, we report a subset of the mammalian prion protein (PrP), also prone to self-assembly, propagation and to cause devastating diseases, is a component of naturally occurring messenger ribonucleoproteins (mRNPs) in adult mouse brains. Biomolecules co-purified with PrP revealed a multitude of diverse RNA granule associated proteins and mRNAs encoding members of the translation machinery, indicating a role in a specialized translation process. Importantly, PrP mutations linked to Creutzfeldt-Jakob disease (CJD) or fatal familial insomnia (FFI) severely impaired recovery of mRNPs from preclinical mice, possibly representing a very early pathological process. Thus, mutant PrP may cause dysfunction in RNA regulation, thereby joining the constantly expanding ranks of disease associated RNP granule proteins. The file Enrichment_analysis.xlsx contains mRNAs (FDR < 0.01) co-purified with PrP in both WT sample pools as identified by DESeq2 and the respective gene counts and log2 fold changes for CJD and FFI PrP:IP sample pools. RIP-Seq analysis of mRNAs co-purified with PrP from murine brain cytoplasmic fractions in wild-type (WT), CJD and FFI mice. Each RIP-Seq and control (input) library represents a pool of 12 to 16 co-immunoprecipitation samples out of 3 to 4 mice. To control for post-homogenization artifacts, we conducted an experiment in which we prepared homogenates from WT and PrP-KO (Prnp-/-) mice of different genetic backgrounds (C57BL/6 and 129S4) and identified SNPs in RIP-Seq and control libraries to finally identify specifically co-purified mRNAs.
2015-11-01 | E-GEOD-57233 | biostudies-arrayexpress
Project description:The molecular function of the cellular prion protein (PrPC) and the mechanism by which it may contribute to neurotoxicity in prion diseases and Alzheimer’s disease (AD) are only partially understood. Mouse neuroblastoma Neuro2a cells and, more recently, C2C12 myocytes and myotubes have emerged as popular models for investigating the cellular biology of PrP. Mouse epithelial NMuMG cells might become attractive models for studying the possible involvement of PrP in a morphogenetic program underlying epithelial-to-mesenchymal transitions. Here we describe the generation of PrP knockout clones from these cell lines using CRISPR-Cas9 knockout technology. More specifically, knockout clones were generated with two separate gRNAs targeting recognition sites on opposite strands within the first hundred nucleotides of the Prnp coding sequence. Several PrP knockout clones were isolated and genomic insertions and deletions near the CRISPR-target sites were characterized. Subsequently, deep quantitative global proteome analyses that recorded the relative abundance of > 3000 proteins were undertaken to begin to characterize the molecular consequences of PrP deficiency. The levels of ~120 proteins were shown to reproducibly correlate with the presence or absence of PrP, with most of these proteins as belonging to extracellular components, cell junctions or the cytoskeleton.
2014-11-19 | PXD001301 | Pride
Project description:Prion protein (PrP) concentration controls the kinetics of prion replication and is a genetically and pharmacologically validated therapeutic target for prion disease. In order to evaluate PrP concentration as a pharmacodynamic biomarker and assess its contribution to known prion disease risk factors, we developed and validated a plate-based immunoassay reactive for PrP across six species of interest and applicable to brain and cerebrospinal fluid (CSF). PrP concentration varies dramatically between different brain regions in mice, cynomolgus macaques, and humans. PrP expression does not appear to contribute to the known risk factors of age, sex, or common PRNP genetic variants. CSF PrP is lowered in the presence of rare pathogenic PRNP variants, with heterozygous carriers of P102L displaying 55% and of D178N just 31% the CSF PrP concentration of mutation-negative controls. In rodents, pharmacologic reduction of brain Prnp RNA is reflected in brain parenchyma PrP, and in turn in CSF PrP, validating CSF as a sampling compartment for the effect of PrP-lowering therapy. Our findings support the use of CSF PrP as a pharmacodynamic biomarker for PrP-lowering drugs, and suggest that relative reduction from individual baseline CSF PrP concentration may be an appropriate marker for target engagement.
2022-02-28 | PXD031432 | panorama
Project description:Prion diseases are fatal transmissible neurodegenerative conditions of humans and animals that arise through neurotoxicity induced by PrP misfolding. The cellular and molecular mechanisms of prion-induced neurotoxicity remain undefined. Understanding these processes will underpin therapeutic and control strategies for human and animal prion diseases, respectively. Prion diseases are difficult to study in their natural hosts and require the use of tractable animal models. Here we used RNA-Seq-based transcriptome analysis of prion-exposed Drosophila to probe the mechanism of prion-induced neurotoxicity. Adult Drosophila transgenic for pan neuronal expression of ovine PrP targeted to the plasma membrane exhibit a neurotoxic phenotype evidenced by decreased locomotor activity after exposure to ovine prions at the larval stage. Pathway analysis and quantitative PCR of genes differentially expressed in prion-infected Drosophila revealed up-regulation of cell cycle activity and DNA damage response, followed by down-regulation of eIF2 and mTOR signalling. Mitochondrial dysfunction was identified as the principal toxicity pathway in prion-exposed PrP transgenic Drosophila. The transcriptomic changes we observed were specific to PrP targeted to the plasma membrane since these prion-induced gene expression changes were not evident in similarly-treated Drosophila transgenic for cytosolic pan neuronal PrP expression, or in non-transgenic control flies. Collectively, our data indicate that aberrant cell cycle activity, repression of protein synthesis and altered mitochondrial function are key events involved in prion-induced neurotoxicity, and correlate with those identified in mammalian hosts undergoing prion disease. These studies highlight the use of PrP transgenic Drosophila as a genetically well-defined tractable host to study mammalian prion biology.
2020-01-31 | GSE144028 | GEO
Project description:In human neurodegenerative diseases associated with the intracellular aggregation of Tau protein, the ordered cores of Tau filaments adopt distinct folds. Here, we analyze Tau filaments isolated from the brain of individuals affected by Prion-Protein cerebral amyloid angiopathy (PrP-CAA) and Gerstmann-Sträussler-Scheinker (GSS) disease, two genetically determined Prion protein (PrP) amyloidoses characterized by the deposition of PrP amyloid (APrP) in the vessel walls and in the cerebral parenchyma, respectively. A nonsense and a missense mutation in the PRNP gene lead to a premature termination of translation at codon position 160 (Q160Ter) of PrP in PrP-CAA, or to the substitution of an amino acid at residue 198 (F198S) of PrP in GSS. These two diseases have different clinical and pathologic phenotypes; however, in both diseases, neuropathologic analyses have consistently shown the presence of numerous neurofibrillary tangles (NFTs) made of filamentous Tau aggregates in neurons. We report that Tau filaments in PrP-CAA and GSS are composed of 3-repeat and 4-repeat Tau isoforms, having a striking similarity to NFTs in Alzheimer disease (AD). In PrP-CAA, Tau filaments are made of both paired helical filaments (PHFs) and straight filaments (SFs), while in GSS only PHFs were found. Mass spectrometry analyses of Tau filaments extracted from PrP-CAA and GSS brains show the presence of post-translational modifications that are comparable to those seen in Tau aggregates from AD. Cryo-EM analysis reveals that the atomic models of the Tau filaments obtained from PrP-CAA and GSS are identical to those of the Tau filaments from AD, and are therefore distinct from those of Pick disease, chronic traumatic encephalopathy, and corticobasal degeneration. Our data support the hypothesis that in the presence of amyloid deposits and regardless of the primary amino acid sequence of the amyloid protein, similar molecular mechanisms are at play in the formation of identical Tau filaments.
2022-02-17 | PXD025663 | Pride