Transmission-selective muscle pathology induced by active propagation of mutant huntingtin across the human neuromuscular synapse

A potential explanation for the spatiotemporal accumulation of pathological lesions in the brain of patients with neurodegenerative protein misfolding diseases (PMDs) is cell-to-cell transmission of aggregation-prone, misfolded proteins. Little is known about central to peripheral transmission and its contribution to pathology. We show that transmission of Huntington’s disease- (HD-) associated mutant HTT exon 1 (mHTTEx1) occurs across the neuromuscular junctions in human iPSC cultures and in vivo in wild-type mice. We found that transmission is an active and dynamic process, that happens prior to aggregate formation and is regulated by synaptic activity. Furthermore, we find that transmitted mHTTEx1 causes HD-relevant pathology at a molecular and functional level in human muscle cells, even in the presence of ubiquitous expression mHTTEx1. With this work we uncover a casual-link between mHTTEx1 synaptic transmission and pathology, highlighting the therapeutic potential in blocking toxic protein transmission in PMDs.

A Field-Deployable Diagnostic Assay for the Visual Detection of Misfolded Prions

Diagnostic tools for the detection of protein-misfolding diseases (i.e., proteopathies) are limited. Gold nanoparticles (AuNPs) facilitate sensitive diagnostic techniques via visual color change for the detection of a variety of targets. In parallel, recently developed quaking-induced conversion (QuIC) assays leverage protein-amplification and fluorescent signaling for the accurate detection of misfolded proteins. Here, we combine AuNP and QuIC technologies for the visual detection of amplified misfolded prion proteins from tissues of wild white-tailed deer infected with chronic wasting disease (CWD), a prion disease of cervids. Our newly developed assay, MN-QuIC™, enables both naked-eye and light-absorbance measurements for detection of misfolded prions. MN-QuIC™ leverages basic laboratory equipment that is cost-effective and portable, thus facilitating real-time prion diagnostics across a variety of settings. To test the portability of our assay, we deployed to a rural field-station in southeastern Minnesota and tested for CWD on site. We successfully demonstrated that MN-QuIC™ is functional in a non-traditional laboratory setting by performing a blinded analysis in the field and correctly identifying all CWD positive and CWD not detected deer at the field site in less than 24 hours, thus documenting the portability of the assay. Additionally, we show that electrostatic forces help govern the AuNP/prion interactions. Importantly, all of our white-tailed deer (n=37) were independently tested using ELISA, IHC, and/or RT-QuIC technologies and results secured with MN-QuIC™ were 100% consistent with these tests. We conclude that hybrid AuNP and QuIC assays, such as MN-QuIC™, have great potential for sensitive, field-deployable diagnostics of a variety of protein misfolding diseases.

Regulation of Hippo pathway by Hsp70-Bag3 complex: Bag3 modulates YAP phosphorylation and its nuclear translocation

Protein abnormalities can accelerate aging causing protein misfolding diseases, various adaptive responses have evolved to relieve proteotoxicity. To trigger these responses, cells must detect the buildup of aberrant proteins. Previously we demonstrated that the Hsp70-Bag3 (HB) complex senses the accumulation of defective ribosomal products, stimulating signaling pathways, such as stress kinases or the Hippo pathway kinase LATS1. Here, we studied how Bag3 regulates the ability for LATS1 to regulate its key downstream target YAP. In naïve cells, Bag3 recruited a complex of LATS1, YAP, and the scaffold AmotL2, which links LATS1 and YAP. Upon inhibition of proteasome, AmotL2 dissociated from Bag3, which prevented phosphorylation of YAP by LATS1 and led to consequent nuclear YAP localization together with Bag3. Mutations in Bag3 that enhanced its translocation into nucleus, also facilitated nuclear translocation of YAP. Interestingly, Bag3 also controlled YAP nuclear localization in response to cell density, indicating broader roles beyond proteotoxic signaling responses for Bag3 in the regulation of YAP. These data implicate Bag3 as a regulator of Hippo pathway signaling, and suggest mechanisms by which proteotoxic stress signals are propagated.

Nanoparticle-Guided Brain Drug Delivery: Expanding the Therapeutic Approach to Neurodegenerative Diseases

Neurodegenerative diseases (NDs) represent a heterogeneous group of aging-related disorders featured by progressive impairment of motor and/or cognitive functions, often accompanied by psychiatric disorders. NDs are denoted as ‘protein misfolding’ diseases or proteinopathies, and are classified according to their known genetic mechanisms and/or the main protein involved in disease onset and progression. Alzheimer’s disease (AD), Parkinson’s disease (PD) and Huntington’s disease (HD) are included under this nosographic umbrella, sharing histopathologically salient features, including deposition of insoluble proteins, activation of glial cells, loss of neuronal cells and synaptic connectivity. To date, there are no effective cures or disease-modifying therapies for these NDs. Several compounds have not shown efficacy in clinical trials, since they generally fail to cross the blood-brain barrier (BBB), a tightly packed layer of endothelial cells that greatly limits the brain internalization of endogenous substances. By engineering materials of a size usually within 1–100 nm, nanotechnology offers an alternative approach for promising and innovative therapeutic solutions in NDs. Nanoparticles can cross the BBB and release active molecules at target sites in the brain, minimizing side effects. This review focuses on the state-of-the-art of nanoengineered delivery systems for brain targeting in the treatment of AD, PD and HD.

Epitope scaffolding using α-synuclein cyclic peptides to generate oligomer-selective antibodies for Parkinson’s disease

Effectively scaffolding epitopes on immunogens, in order to raise conformationally selective antibodies through active immunization, is a central problem in treating protein misfolding diseases, particularly neurodegenerative diseases such as Alzheimer’s disease or Parkinson’s disease. We seek to selectively target conformations enriched in toxic, oligomeric propagating species while sparing the healthy forms of the protein that are often more abundant. To this end, we scaffolded epitopes in cyclic peptides by varying the number of flanking glycines, to best mimic a misfolding-specific conformation of an epitope of α-synuclein enriched in the oligomer ensemble, as characterized by a region most readily disordered and solvent-exposed in a stressed, partially denatured protofibril. We screen and rank the cyclic peptide scaffolds of α-synuclein in silico based on their ensemble overlap properties with the fibril, oligomer-model, and isolated monomer ensembles. We introduce a method for screening against structured off-pathway targets in the human proteome, by selecting scaffolds with minimal conformational similarity between their epitope and the same solvent-exposed primary sequence in structured human proteins. Different cyclic peptide scaffolds with variable numbers of glycines can have markedly different conformational ensembles. Ensemble comparison and overlap was quantified by the Jensen-Shannon Divergence, and a new measure introduced here—the embedding depth, which determines the extent to which a given ensemble is subsumed by another ensemble, and which may be a more useful measure in sculpting the conformational-selectivity of an antibody.

A Review on Protein Misfolding Diseases and therapeutics for preventing Diseases

Background: Protein misfolding sicknesses are the gathering of irresistible lethal neuro and non-neurodegenerative infections and in ebb and flow researchers and specialists accepted that unusual folding of protein is the essential or main key of such illnesses are Alzheimer's infections, Parkinson's diseases, Huntington's sickness, Creutzfeldt-Jakob infection, cystic fibrosis, Gaucher's infection and numerous other degenerative and neurodegenerative problems. The motive of this review article is to gave a detailed of the existing structural information for prion and prion protein and also we will trying to find out their preventing root causes with respect to structural information of prions within the context of what is known about the protein misfolding diseases. Objective: This article presents a brief overview of research on the use of these therapeutics for the treatment or improvement in prion diseases or protein misfolding. Material and Methods: This article begins with the brief introduction about protein misfolding diseases or infections and the therapeutic materials which are used in researches or explain this article (pentosan polysulfate, Quinacrine, Doxycycline, Chaperone based therapy, Resveratrol and curcumin) etc. Results and Conclusions: In this present context of protein misfolding/prion diseases diagonsis.Therapeutic approaches predicts that person infected with prion diseases prolongs the survival time of the patient and improvement in the conditions of the prion diseased infected patient which provides good result for future medicine development. Keywords: Amyloid, Beta-sheet, neurodegenerative, prion, protein misfolding, therapeutics etc

Distinct proteostasis states drive pharmacologic chaperone susceptibility for Cystic Fibrosis Transmembrane Conductance Regulator misfolding mutants

ABSTRACTPharmacological chaperones represent a class of therapeutic compounds for treating protein misfolding diseases. One of the most prominent examples is the FDA-approved pharmacological chaperone lumacaftor (VX-809), which has transformed cystic fibrosis (CF) therapy. CF is a fatal disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). VX-809 corrects folding of F508del CFTR, the most common patient mutation, yet F508del exhibits only mild VX-809 response. In contrast, rarer mutations P67L and L206W are hyper-responsive to VX-809, while G85E is non-responsive. Despite the clinical success of VX-809, the mechanistic origin for the distinct susceptibility of mutants remains unclear. Here, we use interactomics to characterize the impact of VX-809 on proteostasis interactions of P67L and L206W and compare these to F508del and G85E. We determine hyper-responsive mutations P67L and L206W exhibit decreased interactions with proteasomal, and autophagy degradation machinery compared to F508del and G85E. We then show inhibiting the proteasome attenuates P67L and L206W VX-809 response, and inhibiting the lysosome attenuates F508del VX-809 response. Our data suggests a previously unidentified but required role for protein degradation in VX-809 correction. Furthermore, we present an approach for identifying proteostasis characteristics of mutant-specific therapeutic response to pharmacological chaperones.

Amyloid particles facilitate surface-catalyzed cross-seeding by acting as promiscuous nanoparticles

Amyloid seeds are nanometer-sized protein particles that accelerate amyloid assembly as well as propagate and transmit the amyloid protein conformation associated with a wide range of protein misfolding diseases. However, seeded amyloid growth through templated elongation at fibril ends cannot explain the full range of molecular behaviors observed during cross-seeded formation of amyloid by heterologous seeds. Here, we demonstrate that amyloid seeds can accelerate amyloid formation via a surface catalysis mechanism without propagating the specific amyloid conformation associated with the seeds. This type of seeding mechanism is demonstrated through quantitative characterization of the cross-seeded assembly reactions involving two nonhomologous and unrelated proteins: the human Aβ42 peptide and the yeast prion–forming protein Sup35NM. Our results demonstrate experimental approaches to differentiate seeding by templated elongation from nontemplated amyloid seeding and rationalize the molecular mechanism of the cross-seeding phenomenon as a manifestation of the aberrant surface activities presented by amyloid seeds as nanoparticles.

A Novel Method for Creating a Synthetic L-DOPA Proteome and In Vitro Evidence of Incorporation

Proteinopathies are protein misfolding diseases that have an underlying factor that affects the conformation of proteoforms. A factor hypothesised to play a role in these diseases is the incorporation of non-protein amino acids into proteins, with a key example being the therapeutic drug levodopa. The presence of levodopa as a protein constituent has been explored in several studies, but it has not been examined in a global proteomic manner. This paper provides a proof-of-concept method for enzymatically creating levodopa-containing proteins using the enzyme tyrosinase and provides spectral evidence of in vitro incorporation in addition to the induction of the unfolded protein response due to levodopa.