Biology subjects

Wille, H.

Publications and source records attributed to Wille, H..

8 recordsLinked to original sources

bioRxiv2026

Predicted condensation-related signatures localize to two C-terminal regions of the prion protein across cervid PRNP variants associated with chronic wasting disease

Genetic variation in cervid PRNP influences chronic wasting disease (CWD) susceptibility and progression, but it remains unclear whether disease-associated substitutions produce localized differences in sequence-derived properties relevant to prion protein (PrPC) condensation. We compared a white-tailed deer (WTD) reference sequence with 10 modeled variants on the same mature PrP scaffold (residues 24-233). For each sequence, we calculated intrinsic disorder, FuzDrop per-residue droplet-promoting propensity (pDP) and binding-mode entropy (Sbind), predicted residue-level pKa values, and a discrete-charge summary at pH 7.0. The overall profiles preserve a long N-terminal droplet-promoting region, whereas variant-associated differences are concentrated in selected intervals. In the FuzDrop outputs, residues 126-140 show allele-dependent changes in pDP near the droplet-promoting threshold, and residues 220-230 show variant-specific changes in Sbind, including lower Sbind for S225F/Y and higher Sbind for elk-like Q226E. These differences occur without large changes in overall intrinsic disorder. KaML pKa predictions identify near-neutral titratable sites that provide electrostatic context for these local predictor differences. Independent atomistic simulations of monomeric PrP further detected variant-sensitive backbone behavior and intramolecular contacts involving these intervals. Together, the analysis identifies residues 126-140 and 220-230 as computationally defined candidate intervals that overlap regions implicated independently in prion conversion or CWD fibril structure, motivating direct tests of cervid PrP condensation and maturation.

bioinformatics↗

bioRxiv2026

A self-complementary recombinant adeno-associated virus vector coding for an anchorless prion protein carrying the G127V mutation extends survival in a rodent prion disease model

The replacement of a single codon in the human prion gene, causing the substitution of glycine with valine at position 127 (G127V) of the prion protein (PrP), prevents development of prion disease. We set out to explore if prion disease survival extension manifests in mice if the V127 mutant is delivered through a recombinant adeno-associated virus (rAAV) packaged as a self-complementary DNA. The notorious delivery limitations of rAAVs were overcome using a cross-correction approach that relied on the expression of the mutation in the context of glycosylphosphatidylinositoI-anchorless ({Delta}GPI) PrP. In this proof-of-concept study, we inoculated Rocky Mountain Laboratory (RML) prions into knock-in mice, in which the endogenous murine prion protein gene (Prnp) was replaced with the bank vole prion protein gene (BvPrnp). Prion-inoculated mice that were retro-orbitally transduced with a protective rAAV vector encoding BvPrnpV127{Delta}GPI survived [~]50 days longer than control mice that were unprotected. A deep proteomic analysis revealed that BvPrnpV127{Delta}GPI was protective by slowing perturbations to the proteome observed in late-stage RML prion disease. In addition to capturing details of synaptic decay and depletion of proteins in proximity to PrP, the proteomic dataset revealed the identity of proteins of potential diagnostic value that may be central to the brains attempt to fight prion disease by contributing to astrocytosis or microgliosis, by coping with calcium influx, or by enhancing the endoplasmic reticulum processing of essential proteins. Taken together, our results demonstrate that a gene therapy based on a GPI-anchorless PrP containing the G127V mutation can delay the onset of prion disease in mice, providing a framework for development of a corresponding therapy in humans. AUTHOR SUMMARYA rare change in the human prion protein, involving a single building block, has been linked to strong protection against prion diseases--fatal neurodegenerative disorders. This study tested whether that protective effect could be reproduced using gene therapy in mice. To this end, we exposed the animals to infectious prions and then delivered the protective version of the protein into mice using a viral carrier. Treated mice survived about seven weeks longer than untreated animals, showing that the approach can meaningfully slow disease progression. To understand why, we examined changes in brain proteins during disease and found that treatment helped preserve the normal protein levels of cellular proteins, particularly those involved in communication between nerve cells. The analysis also identified proteins altered in the disease that are linked to the brains defense responses, including inflammation, stress handling, and protein processing, some of which may serve as future disease markers. Importantly, the limited protection observed was not due to poor delivery of the therapy but likely reflects biological limits of the model used. Overall, the findings support the idea that gene therapies based on naturally protective human variants could help slow prion diseases and improve understanding of how the brain responds to them.

neuroscience↗

bioRxiv2023

Fibronectin: a natural barrier against prion infection

A distinctive signature of the prion diseases is the accumulation of the pathogenic isoform of the prion protein, PrPSc, in the central nervous system of prion-affected humans and animals. PrPSc is also found in peripheral tissues, raising concerns about the potential transmission of pathogenic prions through human food supplies and posing a significant risk to public health. Although muscle tissues are considered to contain levels of low prion infectivity, it has been shown that myotubes in culture efficiently propagate PrPSc. Given the high consumption of muscle tissue, it is important to understand what factors could influence the establishment of a prion infection in muscle tissue. Here we used in vitro myotube cultures, differentiated from the C2C12 myoblast cell line (dC2C12), to identify factors affecting prion replication. A range of experimental conditions revealed that PrPSc is tightly associated with proteins found in the systemic extracellular matrix (ECM), mostly fibronectin (FN). The interaction of PrPSc with FN decreased prion infectivity, as determined by standard scrapie cell assay. Interestingly, the prion-resistant reserve cells in dC2C12 cultures displayed a FN-rich ECM while the prion-susceptible myotubes expressed FN at a low level. In agreement with the in vitro results, immunohistopathological analyses of tissues from sheep infected with natural scrapie demonstrated a prion susceptibility phenotype linked to an extracellular matrix with undetectable levels of FN. Conversely, PrPSc deposits were not observed in tissues expressing FN. These data indicate that extracellular FN may act as a natural barrier against prion replication and that the extracellular matrix composition may be a crucial feature determining prion tropism in different tissues. Author summaryPrion diseases are complex fatal neurodegenerative disorders caused by a misfolded form of the cellular protein PrPC (PrPSc). Due to the potential zoonotic transmission of these disorders through animal-based food intake, it is crucial to identify the tissues in which PrPSc can accumulate and what might influence its tropism. Animal muscle (or meat) and related food products are highly consumed, raising concern of the involvement of muscle cells in prion replication. Muscle tissue from prion-affected animals contains low levels of infectivity and PrPSc is mostly associated with nerve structures rather than myofibers, whereas C2C12 myotubes, a muscle-derived cell type, efficiently replicate prions in vitro and generate high levels of infectivity compared with other cell cultures. We demonstrate a fibronectin-mediated interference with prion infection in differentiated C2C12 cultures that correlates with the findings in tissues from naturally scrapie-infected animals. Our results suggest that extracellular matrix composition, specifically regarding the presence of fibronectin, might determine prion tropism and dissemination.

biochemistry↗

bioRxiv2023

Rational design of structure-based vaccines targeting misfolded alpha-synuclein conformers of Parkinson's disease and related disorders

BackgroundSynucleinopathies, including Parkinsons disease, multiple system atrophy, and dementia with Lewy bodies, are neurodegenerative disorders caused by the accumulation of misfolded alpha-synuclein protein. Developing effective vaccines against synucleinopathies has been challenging due to the difficulty of stimulating an immune-specific response against alpha-synuclein, conferring neuroprotection without causing harmful autoimmune reactions, and selectively targeting only pathological forms of alpha-synuclein. Previous attempts using linear peptides and epitopes without control of the antigen structure for immunization failed in clinical trials. The immune system was unable to distinguish between the native alpha-synuclein and its amyloid form. ResultsThe prion domain of the fungal HET-s protein was selected as a scaffold to introduce select epitopes from the surface of alpha-synuclein fibrils. Four vaccine candidates were generated by introducing specific amino acid substitutions onto the surface of the scaffold protein in regions that showed structural similarity to alpha-synuclein fibril structures. Each vaccine candidate had unique amino acid substitutions that imitated a specific epitope from alpha-synuclein amyloid fibrils. The approach successfully mimicked the stacking of the parallel in-register beta-sheet structure seen in alpha-synuclein fibrils as the vaccine candidates were found to be structurally stable and self-assembling into the desired conformations. All vaccine candidates induced substantial levels of IgG antibodies that recognized pathological alpha-synuclein fibrils derived from a synucleinopathy mouse model. Furthermore, the resulting anti-sera recognized pathological alpha-synuclein aggregates in brain lysates from patients who died from dementia with Lewy bodies, multiple system atrophy, or Parkinsons disease, but did not recognize linear alpha-synuclein peptides. Each vaccine candidate induced a unique pattern of reactivity toward alpha-synuclein aggregates contained in distinct disease pathologies. ConclusionsThis new approach, based on the rational design of vaccines using the secondary and tertiary structure of alpha-synuclein amyloid fibrils and strict control over the exposed antigen structure used for immunization, as well as the ability to mimic aggregated alpha-synuclein, provides a promising avenue towards developing effective vaccines against alpha-synuclein fibrils, which may be crucial for the prevention and treatment of synucleinopathies.

biochemistry↗

bioRxiv2022

Somatostatin slows Aβ plaque deposition in aged APPNL-F/NL-F mice by blocking Aβ aggregation in a neprilysin-independent manner

The molecular underpinnings that govern the endoproteolytic release of the amyloid beta peptide (A{beta}) from the amyloid precursor protein (APP) are now quite well understood. The same cannot be said for the events that precipitate the aggregation and amyloid deposition of A{beta} in Alzheimers disease (AD). The 14-amino-acid cyclic neuroendocrine peptide somatostatin (SST-14) has long been thought of as playing a role, foremost by controlling the expression of the A{beta} clearing enzyme neprilysin, and more recently by directly interacting with A{beta} oligomers. Missing have been in vivo data in a relevant A{beta} amyloidosis model. Here we addressed this shortcoming by crossing AppNL-F/NL-F mice with Sst-deficient mice of identical genetic background to assess if and how the presence of Sst influences key pathological hallmarks of A{beta} amyloidosis that develop in AppNL-F/NL-F mice after 10 months of age. Surprisingly, we found that Sst had no influence on whole brain neprilysin transcript, protein or activity levels, an observation that cannot be accounted for by a compensatory upregulation of the Sst paralog, cortistatin (Cort), that we observed in 15-month-old Sst-deficient mice. The absence of Sst did lead to a subtle but significant increase in the density of cortical A{beta} amyloid plaques. Follow-on western blot analyses of whole brain extracts indicated that Sst interferes with early steps of A{beta} assembly that manifest in Sst null brains through the appearance of SDS-stable smears of 55- 150 kDa. As expected, no effect of Sst on tau steady-state levels or its phosphorylation were observed. Results from this study are easier reconciled with an emerging body of data that point toward Sst affecting A{beta} amyloid plaque formation through direct interference with A{beta} aggregation rather than through its effects on neprilysin expression.

neuroscience↗

bioRxiv2020

Seizures are a druggable mechanistic link between TBI and subsequent tauopathy

Traumatic brain injury (TBI) is a prominent risk factor for neurodegenerative diseases and dementias including chronic traumatic encephalopathy (CTE). TBI and CTE, like all tauopathies, are characterized by accumulation of Tau into aggregates that progressively spread to other brain regions in a prion-like manner. The mechanisms that promote spreading and cellular uptake of tau seeds after TBI are not fully understood, in part due to lack of tractable animal models. Here, we test the putative roles for excess neuronal activity and dynamin-dependent endocytosis in promoting the in vivo spread of tauopathy. We introduce tauopathy reporter zebrafish expressing a genetically-encoded fluorescent Tau biosensor that reliably reports accumulation of human tau species when seeded via intra-ventricular brain injections. Subjecting zebrafish larvae to a novel TBI paradigm produced various TBI symptoms including cell death, hemorrhage, blood flow abnormalities, post-traumatic seizures, and Tau inclusions. Bath application of anticonvulsant drugs rescued TBI-induced tauopathy and cell death; these benefits were attributable to inhibition of post-traumatic seizures because co-application of convulsants reversed these beneficial effects. However, one convulsant drug, 4-Aminopyridine, unexpectedly abrogated TBI-induced tauopathy - this was due to its inhibitory action on endocytosis as confirmed via additional dynamin inhibitors. These data suggest a role for seizure activity and dynamin-dependent endocytosis in the prion-like seeding and spreading of tauopathy following TBI. Further work is warranted regarding anti-convulsants that dampen post-traumatic seizures as a route to moderating subsequent tauopathy. Moreover, the data highlight the utility of deploying in vivo Tau biosensor and TBI methods in larval zebrafish, especially regarding drug screening and intervention. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/091819v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@34a2caorg.highwire.dtl.DTLVardef@1ab916borg.highwire.dtl.DTLVardef@d83bf2org.highwire.dtl.DTLVardef@47bf90_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIIntroduces first Traumatic Brain Injury (TBI) model in larval zebrafish, and its easy C_LIO_LITBI induces clinically relevant cell death, haemorrhage & post-traumatic seizures C_LIO_LICa2+ imaging during TBI reveals spike in brain activity concomitant with seizures C_LIO_LITau-GFP Biosensor allows repeated in vivo measures of prion-like tau aggregation C_LIO_LIpost-TBI, anticonvulsants stop tauopathies akin to Chronic Traumatic Encephalopathy C_LI

neuroscience↗

bioRxiv2020

Prion protein lowering is a disease-modifying therapy across prion strains, disease stages, and endpoints

Lowering of prion protein (PrP) expression in the brain is a genetically validated therapeutic hypothesis in prion disease. We recently showed that antisense oligonucleotide (ASO)-mediated PrP suppression extends survival and delays disease onset in intracerebrally prion-infected mice in both prophylactic and delayed dosing paradigms. Here, we examine the efficacy of this therapeutic approach across diverse paradigms, varying the dose and dosing regimen, prion strain, treatment timepoint, and examining symptomatic, survival, and biomarker readouts. We recapitulate our previous findings with additional PrP-targeting ASOs, and demonstrate therapeutic benefit against four additional prion strains. We demonstrate that less than 25% PrP suppression is sufficient to extend survival and delay symptoms in a prophylactic paradigm. Rise in both neuroinflammation and neuronal injury markers can be reversed by a single dose of PrP-lowering ASO administered after the detection of pathological change. Chronic ASO-mediated suppression of PrP beginning at any time up to early signs of neuropathology confers benefit similar to constitutive heterozygous PrP knockout. Remarkably, even after emergence of frank symptoms including weight loss, a single treatment prolongs survival by months in a subset of animals. These results support ASO-mediated PrP lowering, and PrP-lowering therapeutics in general, as a promising path forward against prion disease.

neuroscience↗

bioRxiv2018

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), is the only one known to cause epidemic and epizootic episodes(1). Most aggregates of other misfolding-prone proteins are amyloids, often arranged in a Parallel-In-Register-{beta}-Sheet (PIRIBS)(2) or {beta}-solenoid conformations(3). Similar folding models have also been proposed for PrPSc, although none of these have been confirmed experimentally. Recent cryo-electron microscopy (cryo-EM) and X-ray fiber-diffraction studies provided evidence that PrPSc is structured as a 4-rung {beta}-solenoid (4R{beta}S)(4, 5). Here, we combined different experimental data and computational techniques to build the first physically-plausible, atomic resolution model of mouse PrPSc, based on the 4R{beta}S architecture. The stability of this new PrPSc model, as assessed by Molecular Dynamics (MD) simulations, was found to be comparable to that of the prion forming domain of Het-s, a naturally-occurring {beta}-solenoid. Importantly, the 4R{beta}S arrangement allowed the first simulation of the sequence of events underlying PrPC conversion into PrPSc. Our results provide the most updated, experimentally-driven and physically-coherent model of PrPSc, together with an unprecedented reconstruction of the mechanism underlying the self-catalytic propagation of prions.\n\nSignificanceSince the original hypothesis by Stanley Prusiner, prions have represented enigmatic agents diverging from the classical concept of genetic inheritance. However, the structure of PrPSc, the infectious isoform of the cellular prion protein (PrPC), has so far remained elusive, mostly due to technical challenges posed by its aggregation propensity. Here, we present a new high resolution model of PrPSc derived from the integration of a wide array of recent experimental constraints. By coupling the information of such model with a newly developed computational method, we reconstructed for the first time the conformational transition of PrPC to PrPSc. This study offers a unique workbench for designing therapeutics against prion diseases, and a physically-plausible mechanism explaining how protein conformation could self-propagate.

biochemistry↗