Search Results (581)

The causative event in transmissible spongiform encephalopathies is the misfolding of the prion protein (PrP), a process influenced, in a way that is not yet fully understood, by transition metal ions, particularly copper, which modulate folding, aggregation, and redox activity. In this study, we investigated the interaction of copper(II) ions with the prion fragment PrP(95–126), which includes the non-octarepeat high-affinity sites His96 and His111, as well as an amyloidogenic tail involved in PrP misfolding and membrane interaction. UV–vis and circular dichroism analyses revealed the predominant formation of a 1:1 Cu/PrP(95–126) complex, accompanied by modest restructuring, consistent with an increased aggregation propensity upon copper binding. The Cu/PrP(95–126) complexes exhibited limited redox activity toward catechol substrates, which was further reduced in membrane-mimetic systems such as SDS micelles and large unilamellar vesicles (LUVs). His96 appears not to play a critical role in copper coordination or redox activation. This study explores the coordination modes and reactivity of copper(II) with PrP, as well as employing a membrane mimic, aspects that are still highly controversial in the literature, providing insights for further in vitro studies. Full article

Prion diseases are caused by self-propagating and transmissible alternative conformations of certain proteins, which induce neurotoxicity and lead to transmissible spongiform encephalopathy (TSE) in mammalian. Prions were also found in fungi, and in particular, the yeast Saccharomyces cerevisiae. Manganese (Mn) is an essential nutrient and plays crucial roles in central nervous system. However, high concentration of manganese is regarded as an environmental neuronal stressor which would induce striatal neurotoxicity. Long-term exposure to high concentration of manganese would increase the proportion of the infectiously pathogenic isoform (PrPSc) of prion protein. Additionally, increase of manganese levels was found to be age-related in human brain. Here, we studied the effect of manganese on prion using budding yeast prion [URE3] as model organism. We found the exposure to manganese can enhance the de novo generation and propagation of yeast prion [URE3], as well as the expression levels of chaperones Hsp104p and Hsp70p, in a dose-dependent manner. Full article

Prion diseases are fatal neurodegenerative disorders that affect humans and animals, caused by the conformational conversion of the normal cellular prion protein (PrP^C) into its misfolded, infectious isoform PrP^Sc. Recently, camel prion disease (CPrD) was identified in dromedary camels (Camelus dromedarius) in Algeria. Due to the potential implications for animal and human health, as well as the possible socio-economic impact in Mediterranean regions where camels play a pivotal role as a source of food, in-depth characterization of camel prions is important to increase our understanding of camel prion disease. We developed a neuronal cell line model for studying the molecular features of camel prion infection. We genetically edited mouse neuronal CAD5 cells to generate CAD5 PrP knockout (KO) cells. We then used lentiviral transduction to generate CAD5 cells expressing camel PrP (CAD5-camel-PrP). Following infection of these cells with a CPrD-positive camel brain homogenate, we observed PrP^Sc signals at various passages, as indicated by immunoblotting analysis. RT-QuIC (Real-Time Quaking-Induced Conversion) assays further supported these findings, demonstrating transient prion conversion activity in the CPrD-infected CAD5-camel-PrP cells. Taken together, our data describe the first neuronal cell line permissive to camel prion infection, a novel in vitro tool for mechanistic studies of camel prion disease. Full article

Disease-specific alpha-synuclein (αsyn) strains have been linked to different synucleinopathies. Current αsyn biomarkers are limited to binary detection of pathogenic αsyn in peripheral tissue biopsies or fluids, limiting differential diagnosis. Hence, there is an urgent need for methods that allow strain-specific detection and characterization of αsyn strain architecture. Notably, luminescent conjugated oligothiophenes (LCOs) have been successfully used to detect distinct protein strain conformers in prion diseases and Alzheimer’s disease, highlighting their utility in differentiating disease-specific amyloid structures. Species-dependent differences in αsyn structure are increasingly recognized as one of the critical aspects that shape how fibrils form, propagate and interact with molecular LCO probes. Here, we evaluate the potential of the LCO h-FTAA to differentiate species-specific αsyn strains and conduct a translational investigation using peripheral cardiac tissue of a gut-first synucleinopathy rodent model. Our in vitro data demonstrate strain-specific probe–fibril interactions, reflecting a differential strain architecture and cellular micro-environment. While h-FTAA binds with comparable efficiency to mouse (mo-) and human (hu-) pre-formed fibrils (PFFs), h-FTAA exhibits markedly lower quantum yield when bound to moPFFs versus huPFFs. Spectral imaging revealed h-FTAA-moPFF binding produces blue-shifted maxima (505–550 nm), contrasting with the red-shifted maxima (545–580 nm) of huPFFs. Fluorescence lifetime imaging microscopy confirmed h-FTAA’s intrinsic sensitivity to species-dependent variations through distinct temporal fluorescence signatures (moPFFs: ~0.60–1.5 ns vs. huPFFs: ~0.65–1.0 ns). Our translational investigation showed h-FTAA binding to peripheral cardiac pathology exhibits comparable red-shifted emission, but distinct fluorescence lifetimes of h-FTAA-bound aggregates in moPFF-injected (~1.0–1.4 ns) versus huPFF-injected (~0.69–0.8 ns) rats. Interestingly, we observed distinct blue-shifted emission profiles in a few selected regions of the heart of moPFF-injected rodents, further characterized by extra-long fluorescence decay shifts (~1.5–1.9 ns), reflecting differences in both aggregate conformation and maturity in moPFF-induced compared with huPFF-induced rats. Taken together, our findings underscore the potential of LCO ligands, like h-FTAA, to enable more precise disease staging and diagnosis through peripheral biopsies, complementing existing αsyn biomarker methods. Full article

Bovine spongiform encephalopathy (BSE) is a fatal transmissible spongiform encephalopathy caused by the misfolding of the host prion protein (PrP), representing a unique intersection between molecular pathology, neuroanatomy, and public health regulation. Although historically framed as a single feedborne epizootic, BSE is now recognized as a spectrum of strain-defined prion disorders encompassing classical and atypical forms with distinct origins, neuroanatomical trajectories, and surveillance implications. This review integrates advances in prion biology, neurodegenerative mechanisms, and anatomical pathways of neuroinvasion to reframe BSE as a heterogeneous disease entity. We synthesize evidence on PrP^C structure, trafficking, and proteolytic processing to explain how normal cellular physiology enables strain-specific conversion to pathogenic PrP^Sc and subsequent neurotoxicity. Distinct patterns of neuroinvasion and regional vulnerability are discussed for classical versus atypical (H- and L-type) BSE, highlighting differences in lymphoid involvement, brainstem targeting, and cortical or cerebellar tropism. We further examine how these biological differences translate into diagnostic sensitivity, surveillance design, and zoonotic risk assessment. By integrating molecular strain diversity with neuroanatomical connectivity, this review underscores the limitations of obex-centered surveillance for atypical BSE and emphasizes the need for proportionate yet precautionary monitoring strategies. These considerations should be interpreted in light of surveillance-dependent detection biases, which influence the apparent distribution of BSE forms. Ultimately, BSE emerges as a critical model for understanding how protein misfolding disorders bridge cellular mechanisms, animal health, and human public health policy. Full article

Creutzfeldt–Jakob disease (CJD) is a rare and still fatal neurodegenerative disorder caused by prion protein misfolding in the central nervous system. Accumulation of the pathogenic isoform leads to neuronal damage, spongiform degeneration, and rapidly progressive dementia. The disease is divided into sporadic, familial, iatrogenic, and variant forms, with sporadic cases accounting for the majority of cases. Diagnosis remains challenging and relies on a combination of clinical assessment, neuroimaging, and laboratory biomarkers. Key diagnostic methods include electroencephalography, Magnetic Resonance Imaging, and cerebrospinal fluid analysis for proteins as well as advanced amplification tests that improve diagnostic accuracy. Despite these advances, early detection remains challenging and misdiagnosis can occur. Currently, there is no effective disease-modifying therapy, and treatment is primarily supportive, focusing on symptom control and palliative care. Ongoing research aims to better understand the molecular mechanisms underlying prion propagation and develop targeted therapeutic strategies. This review summarizes current diagnostic methods and therapeutic approaches, focusing on molecular applications and their potential clinical implications. Full article

Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative diseases caused by the misfolding of proteins generated in the exon 3 region of the prion protein gene (PRNP). Recent investigations using protein misfolding cyclic amplification assays indicated that some canids displayed a low susceptibility to TSE due to a specific nonsynonymous substitution (human: N159D/E; canid: N163D/E; alignment herein: N302D/E) in the prion protein that may confer protection against prion seeding activity and propagation. To examine the molecular evolution underlying this observation, we determined the mammalian taxonomic distribution of the N159D/E substitution in 882 PRNP sequences representing 26 Orders, 132 families, and 686 species. Two families each in Carnivora (Canidae and Mustelidae) and Chiroptera (Mormoopidae and Vespertilionidae), and one family each in Artiodactyla (Moschidae) and Rodentia (Erethrizontidae), possessed N159D/E that has been reported to confer resistance to TSEs. Although no direct evidence linked a pattern of resistance (phylogenetic relatedness, geographic location, etc.) in these diverse species, it may be that coevolutionary pressures led 53 of the examined 686 species (1 domestic species, 52 wild species) to possess N159D/E. Therefore, the presence of N159D/E may not be the only factor in determining sensitivity to prion diseases; consequently, a more detailed investigation into the 53 species, such as knockout experiments, is warranted. Full article

Neurodegenerative diseases feature diverse pathological protein aggregates, including Lewy bodies in Alzheimer’s disease (AD) and skein-like filaments in amyotrophic lateral sclerosis (ALS). The physical mechanisms underlying this morphological diversity remain unclear. Here, we demonstrate that aggregation of the prion-like domain of hnRNPA1 (A1PrD), implicated in AD and ALS, is driven by solution composition and phase transition dynamics. Utilizing 3D timelapse and fluorescence lifetime imaging microscopy, we show that solution conditions modulate phase separation, gelation, and fibrillation, resulting in distinct structures such as fibril, gel, and starburst morphologies. Homotypic and heterotypic interactions between A1PrD and RNA were observed to shift the balance between pathological and physiological condensates. Importantly, amyloid-rich starbursts displayed prion-like infection capabilities toward amyloid-poor condensates. Our findings highlight how the interplay between solution composition and kinetic balances of liquid-liquid phase separation, gelation, and fibrillation shapes the diverse pathological aggregate morphologies characteristic of neurodegenerative diseases. Full article

Real-time quaking-induced conversion (RT-QuIC) is highly sensitive for prion detection; however, inhibitory factors present in tissue homogenates readily interfere with the assay. We previously reported that recombinant cervid prion protein (rCerPrP) enabled the establishment of practical RT-QuIC for detecting chronic wasting disease and atypical bovine spongiform encephalopathy (BSE) prions, i.e., detecting low levels of prions in high concentration of brain tissue homogenates. Accordingly, the present study aimed to establish RT-QuIC for detecting classical BSE (C-BSE) and classical and atypical scrapie (C- and A-scrapie, respectively). A single-step lipid extraction using a 3:1 mixture of 2-butanol and methanol was effective as a pretreatment to remove inhibitors from brain homogenates. Among three rPrPs extensively evaluated, recombinant sheep PrP (rShPrP) was the most suitable substrate for practical detection of C-BSE prions. rCerPrP-173S/177N and rCerPrP-98S/173S/177N, which carry sheep-type amino acid substations at codons 173 and 177 and at codons 98, 173, and 177, showed excellent performance for detecting C-scrapie prions. Moreover, rCerPrP-98S/173S/177N, but not rCerPrP-173S/177N, was identified as an optimal substrate for detecting A-scrapie prions. These results suggested that combining inhibitor-removal pretreatment with the optimization of rPrP substrate for each animal prions further enhanced of RT-QuIC performance. Full article

Neuronal function relies on the precise coordination between intracellular calcium (Ca²⁺) signaling and the cytoskeletal architecture that underpins synaptic transmission, plasticity, and structural stability. Disruption of this calcium–cytoskeleton interplay has been noted in numerous neurodegenerative diseases. We discuss how Ca²⁺-dependent cytoskeletal remodeling governs long-term potentiation and depression, dendritic spine morphology, and presynaptic function, highlighting the functions of end-binding proteins, STIM (Stromal Interaction Molecule)/Orai-mediated store-operated calcium entry, and the spine apparatus. Disease-specific manifestations of cytoskeletal–calcium dysregulation are reviewed across Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, tauopathies, and prion disorders. Finally, we evaluate emerging therapeutic strategies targeting calcium homeostasis, cytoskeletal dynamics, and their downstream effectors, including multi-target approaches. Full article

Creutzfeldt–Jakob disease (CJD) is a rare, fatal prion disease of the central nervous system that develops due to the conversion of the normal cellular protein PrPc to the abnormal PrPSc molecule. The first clinical cases were described in the 1920s. The aim of this paper is to present the clinical progress of the disease and the diagnostic process, including some of the most common diagnostic traps. The paper highlights a range of symptoms that should serve as a potential warning signal for clinicians—not just neurologists—indicating the need to evaluate the patient more thoroughly. Full article

Prion diseases are fatal neurodegenerative disorders characterized by profound neuronal damage. Despite evidence supporting a neuroprotective role for β-synuclein (β-syn) in neurodegeneration, its potential functions and mechanisms in prion disease have not been elucidated. To investigate the role of β-syn, we systematically analyzed its alterations in the central nervous system of several prion-infected rodent models and cell models. A series of biochemical, cellular, and immunofluorescence assays were conducted to explore the relationship between β-syn and protein kinase B (Akt) signaling and between β-syn and prion protein (PrP), and its neuroprotective role in prion disease. Student’s t-test was used for statistics. At the terminal stage of prion disease, β-syn and Akt exhibited a parallel and remarkable decrease in rodent brains, contrasting with the slight but significant increase observed at early to middle stages. Dual-stained immunofluorescence assays confirmed that β-syn is localized within NeuN-positive neurons. Further structural and functional analyses revealed a high-affinity molecular interaction between β-syn and Akt, with the N-terminal region of β-syn being essential for binding to Akt1. In a cell model of PrP aggregation, β-syn overexpression suppressed cytochrome c-induced apoptosis, which was demonstrated by decreased levels of cleaved caspase-3. Notably, this anti-apoptotic effect was partially abolished upon Akt knockdown, indicating a dependence on Akt signaling. Moreover, colocalization of β-syn and PrP was observed in rodent brains. Consistently, in cellular models of prion infection and PrP aggregation, β-syn overexpression not only reduced PrP levels but also ameliorated its aberrant histological distribution. Our findings demonstrate that the anti-apoptotic activity of β-syn, mediated via Akt signaling, is severely lost during prion infection, thereby suggesting a mechanism of intrinsic neuronal vulnerability and revealing a novel therapeutic strategy. Full article

Alzheimer’s disease (AD) is traditionally defined by Amyloid-β (Aβ) plaques and tau neurofibrillary tangles, yet these proteinopathies alone fail to explain disease heterogeneity, progression, and cognitive decline. Emerging evidence identifies chronic neuroinflammation as a central integrator that converts molecular pathology into synaptic failure and neurodegeneration. In this context, Aβ acts as a danger-associated molecular pattern that activates microglial and astrocytic immune programs through receptors such as TREM2, TLRs, and RAGE, leading to inflammasome activation, cytokine release, and oxidative stress. These responses pathologically re-engage developmental complement pathways (C1q–C3–CR3), driving excessive synaptic pruning that correlates more closely with cognitive impairment than neuronal loss. Reactive astrocytes further amplify dysfunction by impairing glutamate and potassium homeostasis, promoting excitotoxic and metabolic stress, while inflammatory glia facilitate prion-like tau propagation via extracellular vesicles. Concurrent neurovascular inflammation disrupts blood–brain barrier integrity and cerebral perfusion, reinforcing immune-metabolic failure. Importantly, neuroinflammatory biomarkers (GFAP, sTREM2, YKL-40, cytokines, complement, and TSPO-PET) provide dynamic readouts of disease activity and therapeutic response. Together, these findings position AD as a disorder of failed immune resolution and support precision immunomodulatory and pro-resolving therapies aimed at restoring neuroimmune homeostasis rather than merely removing protein aggregates. Full article