bims-proned 2024-12-15 papers

bims-proned

Biomed News

on Proteostasis in neurodegeneration

Issue of 2024–12–15
twenty-two papers selected by
Verena Kohler, Umeå University

Synergistic Multi-Pronged Interactions Mediate the Effective Inhibition of Alpha-Synuclein Aggregation by the Chaperone HtrA1.
Aggregation dynamics of a 150 kDa Aβ42 oligomer: Insights from cryo electron microscopy and multimodal analysis.
An update on immune-based alpha-synuclein trials in Parkinson's disease.
Cytotoxicity of α-synuclein amyloid fibrils generated with phage chaperonin OBP.
Insight Into Factors Influencing the Aggregation Process in Wild-Type and P66R Mutant SOD1: Computational and Spectroscopic Approaches.
Microglia Process α-Synuclein Fibrils and Enhance their Pathogenicity in a TREM2-Dependent Manner.
Chaperone mediated disaggregation of infectious prions releases particles that seed new prion formation in a strain specific manner.
Current concepts and molecular pathology of neurodegenerative diseases.
Selective Inhibition of Cytosolic PARylation via PARG99: A Targeted Approach for Mitigating FUS-associated Neurodegeneration.
Heat Shock Protein Network: the Mode of Action, the Role in Protein Folding and Human Pathologies.
Amygdala-predominant α-synuclein pathology is associated with exacerbated hippocampal neuron loss in Alzheimer's disease.
Advanced Glycation End Products in Neurodegenerative Diseases.
From onset to advancement: the temporal spectrum of α-synuclein in synucleinopathies.
Mitochondrial oxidant stress promotes α-synuclein aggregation and spreading in mice with mutated glucocerebrosidase.
Transmission of Peripheral-blood α-Synuclein Fibrils Exacerbates Synucleinopathy and Neurodegeneration in Parkinson's Disease by Endothelial Lag3 Endocytosis.
Rational design, synthesis and computational studies of multi-targeted anti-Alzheimer's agents integrating coumarin scaffold.
Ion mobility mass spectrometry unveils conformational effects of drug lead EPI-001 on the intrinsically disordered N-terminal domain of the androgen receptor.
NMR studies of amyloid interactions.
Loss of FIC-1-mediated AMPylation activates the UPR ER and upregulates cytosolic HSP70 chaperones to suppress polyglutamine toxicity.
Molecular basis of the development of Parkinson's disease.
Multi-target macrocycles: pyrogallol derivatives to control multiple pathological factors associated with Alzheimer's disease.
The ALS-associated co-chaperone DNAJC7 mediates neuroprotection against proteotoxic stress by modulating HSF1 activity.

bioRxiv. 2024 Nov 28. pii: 2024.11.25.624572. [Epub ahead of print]

Synergistic Multi-Pronged Interactions Mediate the Effective Inhibition of Alpha-Synuclein Aggregation by the Chaperone HtrA1.

Priscilla Chinchilla, Baifan Wang, Joseph H Lubin, Xue Yang, Jonathan Roth, Sagar D Khare, Jean Baum.

The misfolding, aggregation, and the seeded spread of alpha synuclein (α-Syn) aggregates are linked to the pathogenesis of various neurodegenerative diseases, including Parkinson's disease (PD). Understanding the mechanisms by which chaperone proteins prevent the production and seeding of α-Syn aggregates is crucial for developing effective therapeutic leads for tackling neurodegenerative diseases. We show that a catalytically inactive variant of the chaperone HtrA1 (HtrA1*) effectively inhibits both α-Syn monomer aggregation and templated fibril seeding, and demonstrate that this inhibition is mediated by synergistic interactions between its PDZ and Protease domains and α-Syn. Using biomolecular NMR, AFM and Rosetta-based computational analyses, we propose that the PDZ domain interacts with the C-terminal end of the monomer and the intrinsically disordered C-terminal domain of the α-Syn fibril. Furthermore, in agreement with sequence specificity calculations, the Protease domain cleaves in the aggregation-prone NAC domain at site T92/A93 in the monomer. Thus, through multi-pronged interactions and multi-site recognition of α-Syn, HtrA1* can effectively intervene at different stages along the α-Syn aggregation pathway, making it a robust inhibitor of α-Syn aggregation and templated seeding. Our studies illustrate, at high resolution, the crucial role of HtrA1 interactions with both the intrinsically disordered α-Syn monomers and with the dynamic flanking regions around the fibril core for inhibition of aggregation. This inhibition mechanism of the HtrA1 chaperone may provide a natural mechanistic blueprint for highly effective therapeutic agents against protein aggregation.
Significance Statement: PD and other synucleinopathies are marked by misfolding and aggregation of α-Syn, forming higher-order species that propagate aggregation in a prion-like manner. Understanding how chaperone proteins inhibit α-Syn aggregation and spread is essential for therapeutic development against neurodegeneration. Through an integrative approach of solution-based NMR, AFM, aggregation kinetics, and computational analysis, we reveal how a catalytically inactive variant of the chaperone HtrA1 effectively disrupts aggregation pathways. We find that the inactive Protease and PDZ domains of HtrA1 synergistically bind to key intrinsically disordered sites on both α-Syn monomers and fibrils, thereby effectively inhibiting both aggregation and templated seeding. Our work provides a natural and unique blueprint for designing inhibitors to prevent the formation and seeding of aggregates in neurodegenerative diseases.

DOI: https://doi.org/10.1101/2024.11.25.624572
Comput Struct Biotechnol J. 2024 Dec;23 4205-4213

Aggregation dynamics of a 150 kDa Aβ42 oligomer: Insights from cryo electron microscopy and multimodal analysis.

S Shirin Kamalaldinezabadi, Jens O Watzlawik, Terrone L Rosenberry, Anant K Paravastu, Scott M Stagg.

  Protein misfolding is a widespread phenomenon that can result in the formation of protein aggregates, which are markers of various disease states, including Alzheimer's disease (AD). In AD, amyloid beta (Aβ) peptides are key players in the disease's progression, particularly the 40- and 42- residue variants, Aβ40 and Aβ42. These peptides aggregate to form amyloid plaques and contribute to neuronal toxicity. Recent research has shifted attention from solely Aβ fibrils to also include Aβ protofibrils and oligomers as potentially critical pathogenic agents. Particularly, oligomers demonstrate more significant toxicity compared to other Aβ specie. Hence, there is an increased interest in studying the correlation between toxicity and their structure and aggregation pathway. The present study investigates the aggregation of a 150 kDa Aβ42 oligomer that does not lead to fibril formation. Using negative stain transmission electron microscopy (TEM), size exclusion chromatography (SEC), dynamic light scattering (DLS), and cryo-electron microscopy (cryo-EM), we demonstrate that 150 kDa Aβ42 oligomers form higher-order string-like assemblies over time. These strings are unique from the classical Aβ fibrils. The significance of our work lies in elucidating molecular behavior of a novel non-fibrillar form of Aβ42 aggregate.

Keywords:  Alzheimer’s disease; Amyloid fibrils; Aβ42; Aβ42 oligomers; Aβ42 strings; Cryo-electron microscopy; Protein aggregation

DOI:  https://doi.org/10.1016/j.csbj.2024.11.024
J Neurol. 2024 Dec 12. 272(1): 21

An update on immune-based alpha-synuclein trials in Parkinson's disease.

Maha Alfaidi, Roger A Barker, Wei-Li Kuan.

  Parkinson's disease (PD) is a prevalent, chronic neurodegenerative disorder characterised by the progressive loss of dopaminergic neurons in the substantia nigra and other brain regions. The aggregation of alpha-synuclein (α-syn) into Lewy bodies and neurites is a key pathological feature associated with PD and its progression. Many therapeutic studies aim to target these aggregated forms of α-syn to potentially slow down or stop disease progression in PD. This review provides a comprehensive analysis of recent clinical trials involving vaccines and monoclonal antibodies targeting α-syn. Specifically, UB-312, AFFITOPE PD01A, PD03A and ACI-7104.056 are designed to provoke an immune response against α-syn (active immunisation), while Prasinezumab and Cinpanemab, MEDI1341 and Lu AF82422 focus on directly targeting α-syn aggregates (passive immunisation). Despite some promising results, challenges such as variable efficacy and trial discontinuations persist. Future research must address these challenges to advance disease-modifying therapies for PD around this therapeutic target.

Keywords:  Clinical trials; Immune therapy; Neurodegeneration; Parkinson’s disease (PD); α-Synuclein (α-syn)

DOI:  https://doi.org/10.1007/s00415-024-12770-x
Biochem Biophys Res Commun. 2024 Dec 06. pii: S0006-291X(24)01663-2. [Epub ahead of print]742 151127

Cytotoxicity of α-synuclein amyloid fibrils generated with phage chaperonin OBP.

Denis V Pozdyshev, Evgeniia V Leisi, Vladimir I Muronetz, Sergei A Golyshev, Lidia P Kurochkina.

  Chaperonins are known to be important players in the conversion of amyloidogenic proteins into amyloid precursors in a variety of neurodegenerative diseases. However, the mechanisms of their action is still poorly understood. In this work, we used a single-ring chaperonin of the bacteriophage OBP, which functions in an ATP-dependent manner but has a simpler structure than other chaperonins. The effect of the chaperonin OBP on the conversion of human α-synuclein mutant A53T into amyloid was studied and the cytotoxicity of the formed fibrils was investigated. The phage chaperonin OBP was expressed in HEK293T cells together with the human α-synuclein mutant A53T. Both proteins showed a diffuse distribution within the cell cytoplasm as determined by fluorescence microscopy using specific antibodies. Separate and co-expression of the two proteins did not result in the formation of distinguishable protein aggregates in the cells, nor did it have any effect on cell viability. However, the co-expression of chaperonin and α-synuclein did result in the appearance of some dimeric and oligomeric forms of α-synuclein in the insoluble fraction of the cell lysate. It can therefore be concluded that chaperonin OBP stimulates the amyloid transformation of α-synuclein A53T when both proteins are co-expressed in eukaryotic cells. A comparison of the cytotoxicity of mutant α-synuclein amyloid forms obtained in vitro, both during spontaneous fibrillation and with the participation of the chaperonin OBP, showed that the maximum effect on HEK293T and SH-SY5Y cells, resulting in the death of more than 50 % of the population, was exerted by α-synuclein fibrils formed under chaperonin action in the presence of ATP. In the context of recent data on the spread of amyloid α-synuclein from the gut to the brain, the role of phage chaperonins in the pathological aggregation of amyloidogenic proteins in the human body and the potential use of the OBP chaperonin in cellular models of synucleinopathies are discussed.

Keywords:  ATPase activity; Amyloid transformation; Phage chaperonin; Protein aggregation; α-Synuclein

DOI:  https://doi.org/10.1016/j.bbrc.2024.151127
Proteins. 2024 Dec 06.

Insight Into Factors Influencing the Aggregation Process in Wild-Type and P66R Mutant SOD1: Computational and Spectroscopic Approaches.

Roghayeh Farrokhzad, Bagher Seyedalipour, Payam Baziyar, Saman Hosseinkhani.

  Disturbances in metal ion homeostasis associated with amyotrophic lateral sclerosis (ALS) have been described for several years, but the exact mechanism of involvement is not well understood. To elucidate the role of metalation in superoxide dismutase (SOD1) misfolding and aggregation, we comprehensively characterized the structural features (apo/holo forms) of WT-SOD1 and P66R mutant in loop IV. Using computational and experimental methodologies, we assessed the physicochemical properties of these variants and their correlation with protein aggregation at the molecular level. Modifications in apo-SOD1 compared to holo-SOD1 were more pronounced in flexibility, stability, hydrophobicity, and intramolecular interactions, as indicated by molecular dynamics simulations. The enzymatic activities of holo/apo-WT SOD1 were 1.30 and 1.88-fold of the holo/apo P66R mutant, respectively. Under amyloid-inducing conditions, decreased ANS fluorescence intensity in the apo-form relative to the holo-form suggested pre-fibrillar species and amyloid aggregate growth due to occluded hydrophobic pockets. FTIR spectroscopy revealed that apo-WT-SOD1 and apo-P66R exhibited a mixture of parallel and intermolecular β-sheet structures, indicative of aggregation propensity. Aggregate species were identified using TEM, Congo red staining, and ThT/ANS fluorescence spectroscopy. Thermodynamic analyses with GdnHCl demonstrated that metal deficit, mutation, and intramolecular disulfide bond reduction are essential for initiating SOD1 misfolding and aggregation. These disruptions destabilize the dimer-monomer equilibrium, promoting dimer dissociation into monomers and decreasing the thermodynamic stability of SOD1 variants, thus facilitating amyloid/amorphous aggregate formation. Our findings offer novel insights into protein aggregation mechanisms in disease pathology and highlight potential therapeutic strategies against toxic protein aggregation, including SOD1.

Keywords:  amyotrophic lateral sclerosis; apo/holo SOD1; loop IV; molecular dynamics; protein aggregation; simulation

DOI:  https://doi.org/10.1002/prot.26765
Adv Sci (Weinh). 2024 Dec 12. e2413451

Microglia Process α-Synuclein Fibrils and Enhance their Pathogenicity in a TREM2-Dependent Manner.

Min Xiong, Danhao Xia, Honglu Yu, Lanxia Meng, Xingyu Zhang, Jiehui Chen, Ye Tian, Xin Yuan, Xuan Niu, Shuke Nie, Zhaohui Zhang, Chaoyang Liu, Qiang Chen, Keqiang Ye, Zhentao Zhang.

  Parkinson's disease (PD) is characterized by the deposition of misfolded α-synuclein (α-syn) in the brain. Converging evidence indicates that the intracellular transmission and subsequent templated amplification of α-syn are involved in the onset and progression of PD. However, the molecular mechanisms underlying the cell-to-cell transmission of pathological α-syn remain poorly understood. Microglia is highly activated in the brains of PD patients. Here, it is shown that depletion of microglia slows the spread of pathological α-syn pathology in mice injected with α-syn fibrils. Microglia phagocytose α-syn fibrils and transform them into more toxic species. The phagocytosis of α-syn fibrils by microglia is partially mediated by triggering a receptor expressed on myeloid cells 2 (TREM2), a transmembrane protein expressed on the surface of microglia. The endocytosed α-syn fibrils are then cleaved by the lysosomal proteinase asparagine endopeptidase (AEP) to generate truncated α-syn 1-103 fibrils with enhanced seeding activity. Knockout of TREM2 and AEP impedes the endocytosis and cleavage of α-syn fibrils, respectively. The results demonstrate that TREM2-mediated phagocytosis of α-syn fibrils by microglia and subsequent AEP-mediated cleavage of α-syn fibrils contribute to the spread of α-syn in the brain. Blocking either of these two steps attenuates the progression of α-syn pathology.

Keywords:  Parkinson's disease; asparagine endopeptidase; microglia; triggering receptor expressed on myeloid cells 2; α‐synuclein

DOI:  https://doi.org/10.1002/advs.202413451
J Biol Chem. 2024 Dec 09. pii: S0021-9258(24)02564-X. [Epub ahead of print] 108062

Chaperone mediated disaggregation of infectious prions releases particles that seed new prion formation in a strain specific manner.

Daniel Shoup, Suzette A Priola.

  The mammalian prion protein can form infectious, non-native, and protease resistant aggregates (PrPD), which cause lethal prion diseases like human Creutzfeldt-Jakob disease. PrPD seeds the formation of new infectious prions by interacting with and triggering the refolding of the normally soluble mammalian prion protein, PrPC, into more PrPD. Refolding of misfolded proteins in the cell is carried out by molecular chaperones such as Grp78. We have recently shown that Grp78 sensitizes PrPD to proteases, indicating structural alterations and leading to its degradation. However, the process of chaperone mediated PrPD disaggregation, the chaperones involved, and the effect of disaggregation on PrPD seeding activity are unclear. We have now monitored the structural modification, disaggregation, and seeding activity of PrPD from two mouse adapted prion strains, 22L and 87V, in the presence of Grp78 and two forms of the Hsp110 disaggregase chaperone family, Hsp105 and Apg-2. We found that both forms of Hsp110 induced similar amounts of disaggregation and structural change in the protease resistant cores of PrPD from both strains. However, 22L PrPD was more susceptible to destabilization and disaggregation by the chaperones than 87V. Surprisingly, despite disaggregation of both strains, only the 22L PrPD aggregates released by the chaperones had seeding activity, with both forms of Hsp110 enhancing the Grp78 mediated release of these aggregates. Our data show that disassembly of PrPD by Grp78 and Hsp110 chaperones can release seeding particles of PrPD in a strain specific manner, potentially facilitating prion replication and spread.

Keywords:  Apg-2; Chaperone; Grp78; Hsp105; Hsp110; Molecular Chaperone; Prion; Prion Disease; Protein Aggregation; Protein Stability; RT-QuIC; seeding activity

DOI:  https://doi.org/10.1016/j.jbc.2024.108062
Pathology. 2024 Nov 14. pii: S0031-3025(24)00297-6. [Epub ahead of print]

Current concepts and molecular pathology of neurodegenerative diseases.

Shelley L Forrest, Gabor G Kovacs.

  Neurodegenerative diseases are a pathologically, clinically and genetically diverse group of diseases characterised by selective dysfunction, loss of synaptic connectivity and neurodegeneration, and are associated with the deposition of misfolded proteins in neurons and/or glia. Molecular studies have highlighted the role of conformationally altered proteins in the pathogenesis of neurodegenerative diseases and have paved the way for developing disease-specific biomarkers that capture and differentiate the main type/s of protein abnormality responsible for neurodegenerative diseases, some of which are currently used in clinical practice. These proteins follow sequential patterns of anatomical involvement and disease spread in the brain and may also be detected in peripheral organs. Recent studies suggest that glia are likely to have an important role in pathological spread throughout the brain and even follow distinct progression patterns from neurons. In addition to morphological and molecular approaches to the classification of these disorders, a further new stratification level incorporates the structure of protein filaments detected by cryogenic electron microscopy. Rather than occurring in isolation, combined deposition of tau, amyloid-β, α-synuclein and TDP-43 are frequently observed in neurodegenerative diseases and in the ageing brain. These can be overlooked, and their clinicopathological relevance is difficult to interpret. This review provides an overview of disease pathogenesis and diagnostic implications, recent molecular and ultrastructural classification of neurodegenerative diseases, how to approach ageing-related and mixed pathologies, and the importance of the protein-based classification system for practising neuropathologists and clinicians. This review also informs general pathologists about the relevance of ongoing full body autopsy studies to understand the spectrum and pathogenesis of neurodegenerative diseases.

Keywords:  disease classification; mixed pathology; neurodegenerative disease; proteinopathy

DOI:  https://doi.org/10.1016/j.pathol.2024.10.006
bioRxiv. 2024 Nov 26. pii: 2024.11.25.625276. [Epub ahead of print]

Selective Inhibition of Cytosolic PARylation via PARG99: A Targeted Approach for Mitigating FUS-associated Neurodegeneration.

Manohar Kodavati, Vikas H Maloji Rao, Joy Mitra, Muralidhar L Hegde.

Neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) are characterized by complex etiologies, often involving disruptions in functions of RNA/DNA binding proteins (RDBPs) such as FUS and TDP-43. The cytosolic mislocalization and aggregation of these proteins are linked to accumulation of unresolved stress granules (SGs), which exacerbate the disease progression. Poly-ADP-ribose polymerase (PARP)-mediated PARylation plays a critical role in this pathological cascade, making it a potential target for intervention. However, conventional PARP inhibitors are limited by their detrimental effects on DNA repair pathways, which are already compromised in ALS. To address this limitation, we investigated a strategy focused on targeting the cytosolic compartment by expressing the cytosol-specific, natural PAR- glycohydrolase (PARG) isoform, PARG99. Using ALS patient derived FUS mutant induced pluripotent cells (iPSCs) and differentiated neurons, we observed elevated levels of FUS in insoluble fractions in mutant cells compared to mutation-corrected isogenic lines. The insoluble FUS as well as TDP-43 levels increased further in sodium arsenite-treated or oxidatively stressed cells, correlating with accumulation of unresolved SGs. Notably, both PARG99 and PARP inhibitors reduced SG formation and insoluble FUS levels, however, PARG99 treated cells exhibited significantly lower DNA damage markers and improved viability under oxidative and arsenite stress. This study highlights the potential of PARG99 as a cytosol-specific intervention to mitigate FUS-associated toxicity while preserving critical nuclear DNA repair mechanisms, offering a promising strategy for addressing the underlying pathology of ALS and potentially other SG-associated neurodegenerative diseases.

DOI: https://doi.org/10.1101/2024.11.25.625276
Folia Biol (Praha). 2024 ;70(3): 152-165

Heat Shock Protein Network: the Mode of Action, the Role in Protein Folding and Human Pathologies.

Aleksandr Melikov, Petr Novák.

  Protein folding is an extremely complicated process, which has been extensively tackled during the last decades. In vivo, a certain molecular machinery is responsible for assisting the correct folding of proteins and maintaining protein homeostasis: the members of this machinery are the heat shock proteins (HSPs), which belong among molecular chaperones. Mutations in HSPs are associated with several inherited diseases, and members of this group were also proved to be involved in neurodegenerative pathologies (e.g., Alzheimer and Parkinson diseases), cancer, viral infections, and antibiotic resistance of bacteria. Therefore, it is critical to understand the principles of HSP functioning and their exact role in human physiology and pathology. This review attempts to briefly describe the main chaperone families and the interplay between individual chaperones, as well as their general and specific functions in the context of cell physiology and human diseases.

Keywords:  HSP; aggregation; cancer; chaperone; neurodegenerative disease; protein folding

DOI:  https://doi.org/10.14712/fb2024070030152
Brain Commun. 2024 ;6(6): fcae442

Amygdala-predominant α-synuclein pathology is associated with exacerbated hippocampal neuron loss in Alzheimer's disease.

Klara Gawor, Sandra O Tomé, Rik Vandenberghe, Philip Van Damme, Mathieu Vandenbulcke, Markus Otto, Christine A F von Arnim, Estifanos Ghebremedhin, Alicja Ronisz, Simona Ospitalieri, Matthew Blaschko, Dietmar Rudolf Thal.

  Misfolded α-synuclein protein accumulates in 43-63% of individuals with symptomatic Alzheimer's disease. Two main patterns of comorbid α-synuclein pathology have been identified: caudo-rostral and amygdala-predominant. α-Synuclein aggregates have been shown to interact with the transactive response DNA-binding protein 43 (TDP-43) and abnormally phosphorylated tau protein. All these proteins accumulate in the amygdala, which is anatomically connected with the hippocampus. However, the specific role of amygdala-predominant α-synuclein pathology in the progression of Alzheimer's disease and hippocampal degeneration remains unclear. In this cross-sectional study, we analysed 291 autopsy brains from both demented and non-demented elderly individuals neuropathologically. Neuronal density in the CA1 region of the hippocampus was assessed for all cases. We semiquantitatively evaluated α-synuclein pathology severity across seven brain regions and calculated a ratio of limbic to brainstem α-synuclein pathology severity, which was used to stratify the cases into two distinct spreading patterns. In the 99 symptomatic Alzheimer's disease cases, we assessed severity of limbic-predominant age-related TDP-43 neuropathological changes and CA1 phosphorylated tau density. We performed triple fluorescence staining of medial temporal lobe samples with antibodies against phosphorylated TDP-43, α-synuclein and phosphorylated tau. Finally, we employed path analysis to determine the association network of various parameters of limbic pathology in Alzheimer's disease cases and CA1 neuronal density. We identified an association between the amygdala-predominant αSyn pathology pattern and decreased neuronal density in the CA1 region. We found that Alzheimer's disease cases with an amygdala-predominant α-synuclein pattern exhibited the highest TDP-43 severity and prevalence of TDP-43 inclusions in the dentate gyrus among all groups, while those with the caudo-rostral pattern had the lowest severity of Alzheimer's disease neuropathological changes. We observed colocalization of TDP-43, aggregated α-synuclein and hyperphosphorylated tau in cytoplasmic inclusions within hippocampal and amygdala neurons of Alzheimer's disease cases. Path analysis modelling suggests that the relationship between amygdala-predominant α-synuclein pathology and CA1 neuron loss is partially mediated by hippocampal tau and TDP-43 aggregates. Our findings suggest that Alzheimer's disease cases with amygdala-predominant α-synuclein pathology may constitute a distinct group with more severe hippocampal damage, a higher TDP-43 burden and potential interactions among α-synuclein, TDP-43 and hyperphosphorylated tau.

Keywords:  Lewy body disease; dementia; immunohistochemistry; neuropathology; path analysis

DOI:  https://doi.org/10.1093/braincomms/fcae442
J Mol Neurosci. 2024 Dec 10. 74(4): 114

Advanced Glycation End Products in Neurodegenerative Diseases.

Cibin T Raghavan.

  Advanced glycation end products (AGEs) have attracted interest as therapeutic targets for neurodegenerative diseases. AGEs facilitate the onset and progression of various neurogenerative disorders due to their ability to promote cross-linking and aggregation of proteins. Further, the interaction between AGEs and receptor for AGEs (RAGE) activates neuroinflammatory, oxidative stress and excitotoxicity processes that contribute to neuronal cell death. Various therapeutic efforts have targeted lowering the production of AGEs, inhibiting RAGE or inhibiting some of the processes of the AGE-RAGE axis as potential treatments for these disorders. Whereas effective treatments for many neurodegenerative disorders remain elusive, such efforts offer promise to slow the progression of diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD).

Keywords:  Advanced glycation end products; Neurodegenerative diseases; Receptor for advanced glycation end products

DOI:  https://doi.org/10.1007/s12031-024-02297-1
Ageing Res Rev. 2024 Dec 10. pii: S1568-1637(24)00458-6. [Epub ahead of print] 102640

From onset to advancement: the temporal spectrum of α-synuclein in synucleinopathies.

James A Wiseman, Kreesan Reddy, Birger Victor Dieriks.

  This review provides an in-depth analysis of the complex role of alpha-synuclein (α-Syn) in the development of α-synucleinopathies, with a particular focus on its structural diversity and the resulting clinical variability. The ability of α-Syn to form different strains or polymorphs and undergo various post-translational modifications significantly contributes to the wide range of symptoms observed in disorders such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), as well as in lesser-known non-classical α-synucleinopathies. The interaction between genetic predispositions and environmental factors further complicates α-synucleinopathic disease pathogenesis, influencing the disease-specific onset and progression. Despite their common pathological hallmark of α-Syn accumulation, the clinical presentation and progression of α-synucleinopathies differ significantly, posing challenges for diagnosis and treatment. The intricacies of α-Syn pathology highlight the critical need for a deeper understanding of its biological functions and interactions within the neuronal environment to develop targeted therapeutic strategies. The precise point at which α-Syn aggregation transitions from being a byproduct of initial disease triggers to an active and independent driver of disease progression - through the propagation and acceleration of pathogenic processes - remains unclear. By examining the role of α-Syn across various contexts, we illuminate its dual role as both a marker and a mediator of disease, offering insights that could lead to innovative approaches for managing α-synucleinopathies.

Keywords:  Parkinson’s disease; dementia with Lewy bodies; multiple system atrophy; non-classical α-synucleinopathies; α-synuclein; α-synuclein strains; α-synucleinopathies

DOI:  https://doi.org/10.1016/j.arr.2024.102640
NPJ Parkinsons Dis. 2024 Dec 11. 10(1): 233

Mitochondrial oxidant stress promotes α-synuclein aggregation and spreading in mice with mutated glucocerebrosidase.

Pietro La Vitola, Eva M Szegö, Rita Pinto-Costa, Angela Rollar, Eugenia Harbachova, Anthony Hv Schapira, Ayse Ulusoy, Donato A Di Monte.

In this study, heterozygous expression of a common Parkinson-associated GBA1 variant, the L444P mutation, was found to exacerbate α-synuclein aggregation and spreading in a mouse model of Parkinson-like pathology targeting neurons of the medullary vagal system. These neurons were also shown to become more vulnerable to oxidative and nitrative stress after L444P expression. The latter paralleled neuronal formation of reactive oxygen species and led to a pronounced accumulation of nitrated α-synuclein. A causal relationship linked mutation-induced oxidative/nitrative stress to enhanced α-synuclein aggregation and spreading that could indeed be rescued by neuronal overexpression of mitochondrial superoxide dismutase 2. Further evidence supported a key involvement of mitochondria as sources of reactive oxygen species as well as targets of oxidative and nitrative damage within L444P-expressing neurons. These findings support the conclusion that enhanced vulnerability to mitochondrial oxidative stress should be considered an important mechanism predisposing to pathology conversion in carriers of GBA1 mutations.

DOI: https://doi.org/10.1038/s41531-024-00842-8
Am J Physiol Cell Physiol. 2024 Dec 09.

Transmission of Peripheral-blood α-Synuclein Fibrils Exacerbates Synucleinopathy and Neurodegeneration in Parkinson's Disease by Endothelial Lag3 Endocytosis.

Qingrui Duan, Qingxi Zhang, ShuoLin Jiang, Kun Nie, Shujun Feng, Yihui Qiu, Peikun He, Yuxuan Xing, Jiaxuan Liu, Guixian Ma, Yuhu Zhang, Yuyuan Gao, Lijuan Wang.

  Background: Parkinson's disease (PD) is an age-related neurodegenerative disorder. The pathological feature of PD is abnormal alpha-synuclein (α-syn) formation and transmission. Recent evidence demonstrates that α-syn preformed fibrils (α-syn PFF) can be detected in the serum of PD patients. The peripheral-blood α-syn PFF can cross the blood-brain barrier and aggravate neuronal damage, but the mechanism remains to be elucidated. Methods: We constructed the PD mouse models of different severity: the mild pathology (A53T ONLY) and the severe pathology (A53T+Brain FIB); this was followed by α-syn PFFs intravenous injection. Then, we used endothelium-specific Lag3 knockout mice (Lag3-ECs-CKO) to decrease the blood α-syn PFFs spreading. Results: We observed that intravenous transmission of α-syn PFFs significantly aggravated motor deficits, dopaminergic neuron loss, neuroinflammation and pathologic α-syn deposition in A53T ONLY, but not in A53T+Brain FIB. Blocking endothelial Lag3 endocytosis by Lag3-ECs-CKO decreased the blood α-syn PFFs spreading and improved the symptoms and pathogenesis of PD mice. Conclusions: Our findings reveal the role of peripheral-blood α-syn PFFs transmission in the mild pathology or early-stage PD and the mechanism of endothelial Lag3 endocytosis in the pathology of α-syn transmission. Targeting endothelial Lag3 to prevent α-syn from spreading from the blood to the brain may be a disease-modifying therapy in early-stage PD.

Keywords:  Lag3; Parkinson's disease; Peripheral blood; Transmission; α-synuclein fibrils

DOI:  https://doi.org/10.1152/ajpcell.00639.2024
Bioorg Chem. 2024 Dec 02. pii: S0045-2068(24)00929-5. [Epub ahead of print]154 108024

Rational design, synthesis and computational studies of multi-targeted anti-Alzheimer's agents integrating coumarin scaffold.

Menna M A Abd El-Mageed, Manal Abdel Fattah Ezzat, Shaimaa A Moussa, Hatem A Abdel-Aziz, Ghada F Elmasry.

  The traditional theory of "one drug, one target, one illness" has come under scrutiny owing to the multifactorial nature of Alzheimer's disease (AD) and the failure of most of its medications, therefore multi-target directed ligands (MTDLs) are prospective therapeutics for AD. In the present study, we synthesized novel series of coumarin derivatives and assessed their inhibitory actions against hAChE, hBuChE, GSK-3β, tau protein and Aβ aggregation. Compounds 6c and 6h stood out among the others with their multifunctional profile. With IC50 values of 28.88 and 26.03 nM, respectively, compounds 6c and 6h showed outstanding activity as hAChE inhibitors and demonstrated good inhibitory activity against hBuChE with IC50 values of 103.90 and 90.09 nM along with appropriate action against GSK-3β in nanomolar range. Also, both compounds 6c and 6h were found to outperform the reported anti-AD donepezil as tau protein aggregation and amyloid aggregation (Aβ) inhibitors as well as low cytotoxicity on healthy neuroblastoma SHSY5Y and hepatic THLE2 cells. Kinetic analysis and docking studies indicated hAChE dual site (mixed) inhibitory effect of compound 6h. Both compounds 6c and 6h complied with Lipinski's rule of five and were virtually able to cross the BBB. All the data suggested that compounds 6c and 6h have potential as a multifunctional therapy for AD.

Keywords:  Acetylcholinesterase; Alzheimer’s disease; Amyloid-β; Coumarin; Glycogen synthase kinase; Multi-target directed ligands; Tau hyperphosphorylation

DOI:  https://doi.org/10.1016/j.bioorg.2024.108024
Protein Sci. 2025 Jan;34(1): e5254

Ion mobility mass spectrometry unveils conformational effects of drug lead EPI-001 on the intrinsically disordered N-terminal domain of the androgen receptor.

Ikhlas M M Ahmed, Adam Rofe, Martyn C Henry, Eric West, Craig Jamieson, Iain J McEwan, Rebecca Beveridge.

  Intrinsically disordered proteins (IDPs) are important drug targets as they are key actors within cell signaling networks. However, the conformational plasticity of IDPs renders them challenging to characterize, which is a bottleneck in developing small molecule drugs that bind to IDPs and modulate their behavior. In relation to this, ion mobility mass spectrometry (IM-MS) is a useful tool to investigate IDPs, as it can reveal their conformational preferences. It can also offer important insights in drug discovery, as it can measure binding stoichiometry and unveil conformational shifts of IDPs exerted by the binding of small drug-like molecules. Herein, we have used IM-MS to investigate the effect of drug lead EPI-001 on the disordered N-terminal domain of the androgen receptor (AR-NTD). Despite structural heterogeneity rendering the NTD a challenging region of the protein to drug, this domain harbors most, if not all, of the transcriptional activity. We quantify the stoichiometry of EPI-001 binding to various constructs corresponding to functional domains of AR-NTD and show that it binds to separate constructs containing transactivation unit (TAU)-1 and TAU-5, respectively, and that 1-2 molecules bind to a larger construct containing both sequences. We also identify a conformational shift upon EPI-001 binding to the TAU-5, and to a much lesser extent with TAU-1 containing constructs. This work provides novel insight on the interactions of EPI-001 with the AR-NTD, and the structural alterations that it exerts, and positions IM-MS as an informative tool that will enhance the tractability of IDPs, potentially leading to better therapies.

Keywords:  EPI‐001; androgen receptor; intrinsically disordered proteins; ion mobility mass spectrometry; native mass spectrometry; prostate cancer; protein–drug interactions

DOI:  https://doi.org/10.1002/pro.5254
Prog Nucl Magn Reson Spectrosc. 2024 Nov-Dec;144-145:pii: S0079-6565(24)00014-1. [Epub ahead of print]144-145 63-96

NMR studies of amyloid interactions.

David A Middleton.

  Amyloid fibrils are insoluble, fibrous nanostructures that accumulate extracellularly in biological tissue during the progression of several human disorders, including Alzheimer's disease (AD) and type 2 diabetes. Fibrils are assembled from protein monomers via the transient formation of soluble, cytotoxic oligomers, and have a common molecular architecture consisting of a spinal core of hydrogen-bonded protein β-strands. For the past 25 years, NMR spectroscopy has been at the forefront of research into the structure and assembly mechanisms of amyloid aggregates. Until the recent boom in fibril structure analysis by cryo-electron microscopy, solid-state NMR was unrivalled in its ability to provide atomic-level models of amyloid fibril architecture. Solution-state NMR has also provided complementary information on the early stages in the amyloid assembly mechanism. Now, both NMR modalities are proving to be valuable in unravelling the complex interactions between amyloid species and a diverse range of physiological metal ions, molecules and surfaces that influence the assembly pathway, kinetics, morphology and clearance in vivo. Here, an overview is presented of the main applications of solid-state and solution-state NMR for studying the interactions between amyloid proteins and biomembranes, glycosaminoglycan polysaccharides, metal ions, polyphenols, synthetic therapeutics and diagnostics. Key NMR methodology is reviewed along with examples of how to overcome the challenges of detecting interactions with aggregating proteins. The review heralds this new role for NMR in providing a comprehensive and pathologically-relevant view of the interactions between protein and non-protein components of amyloid. Coverage of both solid- and solution-state NMR methods and applications herein will be informative and valuable to the broad communities that are interested in amyloid proteins.

Keywords:  Amyloid fibril; Congo red; Curcumin; EGCG; Flutemetamol; Glycosaminoglycan; HSQC; Heparin; Ligand orientation; Metal ions; Oligomer; Paramagnetic relaxation enhancement; STD NMR; Solid-state NMR; thioflavin T; waterLOGSY

DOI:  https://doi.org/10.1016/j.pnmrs.2024.07.001
bioRxiv. 2024 Nov 28. pii: 2024.11.27.625751. [Epub ahead of print]

Loss of FIC-1-mediated AMPylation activates the UPR ER and upregulates cytosolic HSP70 chaperones to suppress polyglutamine toxicity.

Kate M Van Pelt, Matthias C Truttmann.

Targeted regulation of cellular proteostasis machinery represents a promising strategy for the attenuation of pathological protein aggregation. Recent work suggests that the unfolded protein response in the endoplasmic reticulum (UPR ER ) directly regulates the aggregation and toxicity of expanded polyglutamine (polyQ) proteins. However, the mechanisms underlying this phenomenon remain poorly understood. In this study, we report that perturbing ER homeostasis in Caenorhabditis elegans through the depletion of either BiP ortholog, hsp-3 or hsp-4, causes developmental arrest in worms expressing aggregation-prone polyQ proteins. This phenotype is rescued by the genetic deletion of the conserved UPR ER regulator, FIC-1. We demonstrate that the beneficial effects of fic-1 knock-out (KO) extend into adulthood, where the loss of FIC-1-mediated protein AMPylation in polyQ-expressing animals is sufficient to prevent declines in fitness and lifespan. We further show that loss of hsp-3 and hsp-4 leads to distinct, but complementary transcriptomic responses to ER stress involving all three UPR ER stress sensors (IRE-1, PEK-1, and ATF-6). We identify the cytosolic HSP70 family chaperone F44E5.4 , whose expression is increased in fic-1 -deficient animals upon ER dysregulation, as a key effector suppressing polyQ toxicity. Over-expression of F44E5.4 , but not other HSP70 family chaperones, is sufficient to rescue developmental arrest in polyQ-expressing embryos upon hsp-3 knock-down. Finally, we show that knock-down of ire-1 , pek-1 , or atf-6 blocks the upregulation of F44E5.4 in fic-1 -deficient worms. Taken together, our findings support a model in which the loss of FIC-1-mediated AMPylation engages UPR ER signaling to upregulate cytosolic chaperone activity in response to polyQ toxicity.

DOI: https://doi.org/10.1101/2024.11.27.625751
Neuroscience. 2024 Dec 07. pii: S0306-4522(24)00710-3. [Epub ahead of print]565 292-300

Molecular basis of the development of Parkinson's disease.

Margarita Absalyamova, Dmitrii Traktirov, Viktoria Burdinskaya, Valeria Artemova, Zamira Muruzheva, Marina Karpenko.

  Parkinson's disease is one of the most prevalent neurodegenerative motor disorders worldwide with postural instability, bradykinesia, resting tremor and rigidity being the most common symptoms of the disease. Despite the fact that the molecular mechanisms of Parkinson's disease pathogenesis have already been well described, there is still no coherent picture of the etiopathogenesis of this disease. According to modern concepts, neurodegeneration is induced mainly by oxidative stress, neuroinflammation, dysregulation of cerebral proteostasis, apoptotic dysregulation, and impaired autophagy. This review describes how various factors contribute to neurodegeneration in Parkinson's disease. Understanding the factors affecting fundamental cellular processes and responsible for disease progression may help develop therapeutic strategies to improve the quality of life of patients suffering from the disease. The review also discusses the role of calpains in the development of Parkinson's disease. It is known that α-synuclein is a substrate of calcium-dependent proteases of the calpain family. Truncated forms of α-synuclein are not only involved in the process of formation of the aggregates, but also increase their toxicity.

Keywords:  Alpha synuclein; Calpains; Dopaminergic neurons; Molecular pathways; Parkinson’s disease

DOI:  https://doi.org/10.1016/j.neuroscience.2024.12.009
Chem Sci. 2024 Dec 03.

Multi-target macrocycles: pyrogallol derivatives to control multiple pathological factors associated with Alzheimer's disease.

Jimin Kwak, Yelim Yi, Seongmin Park, Mi Hee Lim.

Designing multi-target chemical tools is a vital approach to understanding the pathology of Alzheimer's disease (AD), which involves a complex network of pathological factors, such as free organic radicals, amyloid-β (Aβ), and metal-bound Aβ (metal-Aβ). The pyrogallol moiety, known for its ability to lower redox potentials and interact with both Aβ and metal ions, presents a promising framework for this molecular design. Here we show how simple structural variations of pyrogallol can be used to enhance its ability to scavenge free organic radicals and regulate the aggregation of both metal-free Aβ and metal-Aβ. By incorporating multiple pyrogllol units into a macrocyclic scaffold via methylene bridges, we achieve synergistic reactivity against several pathological targets. Our structure-reactivity relationship studies also reveal that the macrocyclic structure noticeably improves antioxidant activity as well as interactions with both Aβ and metal ions, leading to oxidation of Aβ peptides and influencing their conformation and aggregation in both the absence and presence of metal ions. This work demonstrates the potential of simple redox-active structural entities in developing multifunctional chemical reagents that effectively manage the pathological components associated with AD.

DOI: https://doi.org/10.1039/d4sc06417h
bioRxiv. 2024 Dec 01. pii: 2024.12.01.626216. [Epub ahead of print]

The ALS-associated co-chaperone DNAJC7 mediates neuroprotection against proteotoxic stress by modulating HSF1 activity.

Andrew C Fleming, Nalini R Rao, Matthew Wright, Jeffrey N Savas, Evangelos Kiskinis.

The degeneration of neurons in patients with amyotrophic lateral sclerosis (ALS) is commonly associated with accumulation of misfolded, insoluble proteins. Heat shock proteins (HSPs) are central regulators of protein homeostasis as they fold newly synthesized proteins and refold damaged proteins. Heterozygous loss-of- function mutations in the DNAJC7 gene that encodes an HSP co-chaperone were recently identified as a cause for rare forms of ALS, yet the mechanisms underlying pathogenesis remain unclear. Using mass spectrometry, we found that the DNAJC7 interactome in human motor neurons (MNs) is enriched for RNA binding proteins (RBPs) and stress response chaperones. MNs generated from iPSCs with the ALS-associated mutation R156X in DNAJC7 exhibit increased insolubility of its client RBP HNRNPU and associated RNA metabolism alterations. Additionally, DNAJC7 haploinsufficiency renders MNs increasingly susceptible to proteotoxic stress and cell death as a result of an ablated HSF1 stress response pathway. Critically, expression of HSF1 in mutant DNAJC7 MNs is sufficient to rescue their sensitivity to proteotoxic stress, while postmortem ALS patient cortical neurons exhibit a reduction in the expression of HSF1 pathway genes. Taken together, our work identifies DNAJC7 as a crucial mediator of HNRNPU function and stress response pathways in human MNs and highlights HSF1 as a therapeutic target in ALS.

DOI: https://doi.org/10.1101/2024.12.01.626216