New preclinical biomarkers for prion diseases in the cerebrospinal fluid proteome revealed by mass spectrometry.

Current diagnostic methods for prion diseases only work in late stages of the disease when neurodegeneration is irreversible. Therefore, biomarkers that can detect the disease before the onset of clinical symptoms are necessary. High-throughput discovery proteomics is of great interest in the search for such molecules.

Erratum: A tetracationic porphyrin with dual anti-prion activity.

[This corrects the article DOI: 10.1016/j.isci.

Understanding the key features of the spontaneous formation of bona fide prions through a novel methodology that enables their swift and consistent generation.

Among transmissible spongiform encephalopathies or prion diseases affecting humans, sporadic forms such as sporadic Creutzfeldt-Jakob disease are the vast majority. Unlike genetic or acquired forms of the disease, these idiopathic forms occur seemingly due to a random event of spontaneous misfolding of the cellular PrP (PrP) into the pathogenic isoform (PrP). Currently, the molecular mechanisms that trigger and drive this event, which occurs in approximately one individual per million each year, remain completely unknown.

A tetracationic porphyrin with dual anti-prion activity.

Prions are deadly infectious agents made of PrP, a misfolded variant of the cellular prion protein (PrP) which self-propagates by inducing misfolding of native PrP. PrP can adopt different pathogenic conformations (prion strains), which can be resistant to potential drugs, or acquire drug resistance, hampering the development of effective therapies. We identified Zn(II)-BnPyP, a tetracationic porphyrin that binds to distinct domains of native PrP, eliciting a dual anti-prion effect.

A Mass Spectrometry-Based Method of Quantifying the Contribution of the Lysine Polymorphism at Position 171 in Sheep PrP.

In sheep, the transmissibility and progression of scrapie, a sheep prion (PrP) disease, is strongly dependent upon specific amino acid polymorphisms in the natively expressed prion protein (PrP). Sheep expressing PrP with lysine (K) polymorphism at position 171 (K171) are partially resistant to oronasal dosing of classical sheep scrapie. In addition, scrapie infected sheep expressing the K171 polymorphism show a longer incubation period compared to sheep homozygous (glutamine (Q)) at position 171.

Celia's Encephalopathy (-Gene-Related): Current Understanding.

Seipin, encoded by the gene, is a protein that in humans is expressed mainly in the central nervous system. Uniquely, certain variants in can cause both generalized congenital lipodystrophy type 2, upper and/or lower motor neuron diseases, or progressive encephalopathy, with a poor prognosis during childhood. The latter, Celia's encephalopathy, which may or may not be associated with generalized lipodystrophy, is caused by the c.

Time of Detection of Prions in the Brain by Nanoscale Liquid Chromatography Coupled to Tandem Mass Spectrometry Is Comparable to Animal Bioassay.

Prions cause transmissible and inevitably fatal neurological diseases in agriculturally important animals, including bovine spongiform encephalopathy in domestic cattle, scrapie in sheep and goats, and chronic wasting disease in cervids. Because animals are largely asymptomatic throughout the course of the disease, early detection of prion disease is important. Hamsters were peripherally (ip) inoculated with hamster-adapted (Sc237) prions.

Pharmacological inactivation of the prion protein by targeting a folding intermediate.

Recent computational advancements in the simulation of biochemical processes allow investigating the mechanisms involved in protein regulation with realistic physics-based models, at an atomistic level of resolution. These techniques allowed us to design a drug discovery approach, named Pharmacological Protein Inactivation by Folding Intermediate Targeting (PPI-FIT), based on the rationale of negatively regulating protein levels by targeting folding intermediates. Here, PPI-FIT was tested for the first time on the cellular prion protein (PrP), a cell surface glycoprotein playing a key role in fatal and transmissible neurodegenerative pathologies known as prion diseases.

Modeling PrP Generation Through Deformed Templating.

Deformed templating is the process by which self-replicating protein conformations with a given cross-β folding pattern can seed formation of an alternative self-replicating state with different cross-β folding pattern. In particular, uninfectious but propagative PrP amyloid can transform into a infectious conformer, PrP through deformed templating. The process can take many rounds of replication (if taking place ) or even several passages of the evolving PrP conformers through successive brains if , through experimental transmission.

Understanding prion structure and conversion.

Since their original identification, prions have represented enigmatic agents that defy the classical concept of genetic inheritance. For almost four decades, the high-resolution structure of PrP, the infectious and misfolded counterpart of the cellular prion protein (PrP), has remained elusive, mostly due to technical challenges posed by its high insolubility and aggregation propensity. As a result, such a lack of information has critically hampered the search for an effective therapy against prion diseases.

All-atom simulation of the HET-s prion replication.

Prions are self-replicative protein particles lacking nucleic acids. Originally discovered for causing infectious neurodegenerative disorders, they have also been found to play several physiological roles in a variety of species. Functional and pathogenic prions share a common mechanism of replication, characterized by the ability of an amyloid conformer to propagate by inducing the conversion of its physiological, soluble counterpart.

The protean prion protein.

The prion protein, PrP, can adopt at least 2 conformations, the overwhelmingly prevalent cellular conformation (PrPC) and the scrapie conformation (PrPSc). PrPC features a globular C-terminal domain containing 3 α-helices and a short β-sheet and a long flexible N-terminal tail whose exact conformation in vivo is not yet known and a metastable subdomain with β-strand propensity has been identified within it. The PrPSc conformation is very rare and has the characteristics of an amyloid.

Human VGF-Derived Antidepressant Neuropeptide TLQP62 Promotes SH-SY5Y Neurite Outgrowth.

TLQP62 is a neuropeptide derived from the neurotrophin-inducible VGF (non-acronymic) protein with antidepressant-like properties capable of inducing increased memory on the mouse hippocampus by promoting neurogenesis and synaptic plasticity through brain-derived neurotropic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB). Human SH-SY5Y neuroblastoma-derived cell line is widely used in neuroscience research and is known to undergo neurodifferentiation in the presence of all-trans retinoic acid by upregulating the expression of TrkB, making cells responsive to BDNF. As TLQP62 promotes BDNF expression, which in turn activates a BDNF/TrkB/CREB (cAMP response element-binding protein) pathway that upregulates VGF expression, there is a VGF-BDNF regulatory loop that seems to regulate neurogenesis.

Full atomistic model of prion structure and conversion.

Prions are unusual protein assemblies that propagate their conformationally-encoded information in absence of nucleic acids. The first prion identified, the scrapie isoform (PrPSc) of the cellular prion protein (PrPC), caused epidemic and epizootic episodes [1]. Most aggregates of other misfolding-prone proteins are amyloids, often arranged in a Parallel-In-Register-β-Sheet (PIRIBS) [2] or β-solenoid conformations [3].

Ok Google, how could I design therapeutics against prion diseases?

A number of previous successful attempts in the search for therapeutics for a variety of human pathologies highlight the importance of computational technologies in the drug discovery pipeline. This approach, often referred to as computer-aided drug design, is unfortunately inapplicable when the precise information regarding the three-dimensional structure of disease-associated proteins or the mechanism by which they are altered to generate misfolded isoforms are missing. A typical example is represented by prion diseases, fatal pathologies of the nervous system characterized by the conformational conversion of a physiological protein called PrP into a misfolded and infectious isoform referred to as PrP.

The prion 2018 round tables (I): the structure of PrP.

Understanding the structure of PrP is without doubt a sine qua non to understand not only PrP propagation, but also critical features of that process such as the strain phenomenon and transmission barriers. While elucidation of the PrP structure has been full of difficulties, we now have a large amount of structural information that allows us to begin to understand it. This commentary article summarizes a round table that took place within the Prion 2018 meeting held in Santiago de Compostela to discuss the state of the art in this matter.

Proteomic Studies Reveal Disrupted in Schizophrenia 1 as a Player in Both Neurodevelopment and Synaptic Function.

A balanced chromosomal translocation disrupting DISC1 (Disrupted in Schizophrenia 1) gene has been linked to psychiatric diseases, such as major depression, bipolar disorder and schizophrenia. Since the discovery of this translocation, many studies have focused on understating the role of the truncated isoform of DISC1, hypothesizing that the gain of function of this protein could be behind the neurobiology of mental conditions, but not so many studies have focused in the mechanisms impaired due to its loss of function. For that reason, we performed an analysis on the cellular proteome of primary neurons in which DISC1 was knocked down with the goal of identifying relevant pathways directly affected by DISC1 loss of function.

The Structure of PrP Prions.

PrP (scrapie isoform of the prion protein) prions are the infectious agent behind diseases such as Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy in cattle, chronic wasting disease in cervids (deer, elk, moose, and reindeer), as well as goat and sheep scrapie. PrP is an alternatively folded variant of the cellular prion protein, PrP, which is a regular, GPI-anchored protein that is present on the cell surface of neurons and other cell types. While the structure of PrP is well studied, the structure of PrP resisted high-resolution determination due to its general insolubility and propensity to aggregate.

Recombinant PrPSc shares structural features with brain-derived PrPSc: Insights from limited proteolysis.

Very solid evidence suggests that the core of full length PrPSc is a 4-rung β-solenoid, and that individual PrPSc subunits stack to form amyloid fibers. We recently used limited proteolysis to map the β-strands and connecting loops that make up the PrPSc solenoid. Using high resolution SDS-PAGE followed by epitope analysis, and mass spectrometry, we identified positions ~116/118, 133-134, 141, 152-153, 162, 169 and 179 (murine numbering) as Proteinase K (PK) cleavage sites in PrPSc.

Determining the Relative Susceptibility of Four Prion Protein Genotypes to Atypical Scrapie.

Atypical scrapie is a sheep prion (PrP) disease whose epidemiology is consistent with a sporadic origin and is associated with specific polymorphisms of the normal cellular prion protein (PrP). To determine the relative amounts of PrP polymorphisms present in atypical scrapie, total PrP was digested with chymotrypsin to generate characteristic peptides spanning relevant polymorphisms at positions 136, 141, 154, 171, and 172 of sheep PrP. A multiple reaction monitoring method (MRM), employing N-labeled internal standards, was used to detect and quantify these polymorphisms present in both the PrP and PrP from heterozygous (ALRRY and ALHQY or ALRQD or AFRQY) atypical scrapie-infected or uninfected control sheep.

Cofactors influence the biological properties of infectious recombinant prions.

Prion diseases are caused by a misfolding of the cellular prion protein (PrP) to a pathogenic isoform named PrP. Prions exist as strains, which are characterized by specific pathological and biochemical properties likely encoded in the three-dimensional structure of PrP. However, whether cofactors determine these different PrP conformations and how this relates to their specific biological properties is largely unknown.