Protein Aggregation Research Articles

Impact of protein aggregation on the immunogenicity of a human monoclonal antibody following pulmonary administration in mice

Spray drying is a widely employed method for generating dry powder formulations for inhalation. Yet, it presents substantial challenges when applied to therapeutic proteins due to stability issues. The formation of protein aggregates during the atomization and the heating steps can diminish protein activity and raise immunogenicity concerns. Here, we assessed the impact of varying levels of protein aggregates generated during spray-drying on the fate and the immunogenicity of the human monoclonal antibody NIP228 following intratracheal administration in mice. Aggregate-free rhodamine labelled NIP228 was spray-dried with or without 1% polysorbate 80 surfactant, resulting in the generation of powder formulations with associated low and high protein aggregate levels, respectively. Confocal imaging highlighted the presence of aggregates in the lungs for both powders but not for the solution, while flow cytometry analysis designated alveolar macrophages as the main immune cells taking up rhod-NIP228 in the lungs with very little involvement of dendritic cells and interstitial macrophages following a single dose administration. Notably, repeated intratracheal administration of the three formulations in mice did not impact the magnitude of the anti-drug antibody response in sera or broncho-alveolar lavages. The pulmonary route appeared to evoke a more robust immune response when compared to subcutaneous administration. Overall, the level of NIP228 aggregation in this study did not appear to be the primary driver of NIP228 immunogenicity following delivery to the lungs in mice, shedding new light on the interplay between protein aggregation and immunogenicity in the context of the pulmonary delivery of therapeutic proteins.

Exploring the rhodanine universe: Design and synthesis of fluorescent rhodanine-based derivatives as anti-fibrillar and anti-oligomer agents against α-synuclein and 2N4R tau

Tau and α-synuclein (α-syn) are prone-to-aggregate proteins that coprecipitate in the brains of Alzheimer’s disease (AD) and Parkinson’s disease (PD) patients. The early-stage oligomers and protofibrils of tau are believed to be strongly linked to human cognitive impairment while the toxic α-syn oligomers are associated with behavioral motor deficits. Therefore, concurrent targeting of both proteinaceous aggregates and their lower dense oligomers are very challenging. Herein, rhodanine-based compounds were designed and synthesized to tackle the fibrils and oligomers of tau and α-syn proteins. In particular, the indole-containing rhodanines 5l and 5r displayed significantly high anti-aggregation activity towards α-syn fibrils by reduction of the thioflavin-T (ThT) fluorescence to lower than 5 %. Moreover, 5r showed a remarkable decrease in the fluorescence of thioflavin-S (ThS) when incubated with the non-phosphorylated tau 0N4R and 2N4R as well as the hyperphosphorylated tau isoform 1N4R, respectively. Transmission electron microscopy (TEM) analyses validated the powerful anti-fibrillar activity of 5l and 5r towards both protein aggregates. In addition, both 5l and 5r highly suppressed 0N4R tau and α-syn oligomer formation using the photo-induced cross-linking of unmodified Protein (PICUP) assay. The fluorescence emission intensity of 5l was quenched to almost half in the presence of both protein fibrils at 510 nm. 5r showed a similar fluorescence response upon binding to 2N4R fibrils while no quenching effect was observed with α-syn aggregates. Ex vivo disaggregation assay using extracted human Aβ plaques was employed to confirm the ability of 5l and 5r to disaggregate the dense fibrils. Both inhibitors showed no promising activity towards the cell-based α-syn inclusion formation. However, another indolyl derivative 5j prevented the α-syn inclusion at 5 µM. Collectively, the indolyl-rhodanine scaffold could act as a building block for further structural optimization to obtain dual targeting disease-modifying candidates for AD and PD.

Effect of high-pressure homogenization optimized by response surface methodology on the techno-functional properties of protein concentrate isolated from date seed

The study investigates the impact of high-pressure homogenization (HPH) optimized using response surface methodology (RSM) on the techno-functional properties of protein concentrate isolated from date seeds. The protein concentrate was subjected to HPH at various pressures (50, 100, and 150 MPa) and protein concentrations (1 %, 2 %, and 3 %) to optimize solubility, emulsifying activity, and antioxidant properties. RSM indicated optimal conditions at 150 MPa and 1 % protein concentration, resulting in significant enhancements in solubility (14.10 % to 43.69 %) and antioxidant activity (60.5 TE/g to 71.67 TE/g). The emulsifying activity index (EAI) increased from 11.92 m²/g to 22.29 m²/g, though the emulsion stability index (ESI) slightly decreased from 17.63 min to 16.15 min. Besides, HPH improved oil-binding capacity (1.73 g/g to 3.02 g/g) while reducing water-binding capacity (2.76 g/g to 1.38 g/g). Structural analysis revealed that HPH caused partial protein unfolding and aggregation, indicated by changes in FTIR spectra, reduced fluorescence intensity, and increased surface sulfhydryl content (1.58 µmol/g to 2.65 µmol/g). These findings highlight HPH as an effective method to enhance the functional properties of date seed protein concentrate for potential applications in the food industry. In addition, the current study can lay a foundation for future HPH applications in other protein-rich by-products such as soybean cake, rapeseed cake, wheat bran, and others.

Effects of interaction between wheat bran dietary fiber and gluten protein on gluten protein aggregation behavior.

Effects of wheat bran dietary fiber (WBDF) as a nutritional additive on flour products quality mainly depends on the interaction between WBDF and gluten protein. In this study, the effects and mechanisms of WBDF with different particle sizes and additive amounts on gluten protein aggregation behavior were investigated. The results showed that the addition of WBDF led to a decrease in free sulfhydryl content, particle size, molecular weight and gluten macromer (GMP) content, an increase in zeta potential and SDS-extractable protein content, and a deterioration in the gluten network morphology compared to the control group, suggesting that the aggregation behavior of gluten protein was inhibited. When WBDF was added at 3 % and 6 %, dilution effect, mechanical shear, steric hindrance, and non-covalent binding were the main mechanisms leading to depolymerization. Further addition of WBDF (9 %, 12 %) inhibited the depolymerization of gluten protein due to competitive hydration and non-covalent binding. However, when WBDF was added at 15 %, the dilution effect, mechanical shear and steric hindrance of WBDF (88 μm < particle size<150 μm) dominated, and their inhibitory of aggregation induced the formation of a loose gluten network structure. In contrast, the weaker mechanical shear and steric hindrance effects of WBDF (particle size<88 μm) mitigated the degradation of gluten network structures by WBDF.

Use of different impregnation methods with chitosan to improve the quality of ultrasound-assisted immersion frozen sea bass (Lateolabrax maculatus)

This study investigated the effect of chitosan oligosaccharide (COS) as a cryoprotectant on the water holding capacity (WHC), myofibrillar proteins (MPs), and quality of sea bass frozen by ultrasound-assisted immersion freezing (UIF), and also investigated the effect of different impregnation methods: vacuum impregnation (VI), ultrasound-assisted impregnation (UI), and ultrasound-assisted VI (US-VI). The results indicated that compared with general impregnation in deionized water (GWI) samples, the samples impregnated with COS had lower thawing loss, higher whiteness, lower carbonyl content, more stable secondary and tertiary structures, and smaller ice crystal pore size. These results indicate that COS impregnation of sea bass can reduce large ice crystals and decrease proteins aggregation, resulting in better quality. In addition, US-VI in COS (US-VCI) resulted in improved WHC, whiteness, sulfhydryl content, and Ca2+-ATPase activity of sea bass because of the joint action of ultrasound and vacuum, as well as more stable secondary structure and fine ice crystals.

Fabrication and characterization of acidic high internal phase emulsion gels stabilized solely by wheat gluten for plant-based mayonnaise

Plant-based diets are currently gaining more popularity as a means of reducing the environmental footprint and promoting human health. Herein, plant protein-based acidic high internal phase emulsion gels (HIPE gels) were fabricated via a facile one-pot approach using wheat gluten (WG) solely. Pre-dissolving WG in edible vinegar-water solution was contributed to the fabrication of stable emulsion gels. Factors that affect the structure and performance of plant proteins as HIPE gels stabilizers were investigated. The results indicated that the stable HIPE gels could be formed with a vinegar concentration between 5 % and 20 % and a WG concentration of 1.0 %–7.5 % only. Microscopy images reveal that a collaboration of the soluble protein molecules adsorption and protein aggregate Pickering stabilization at oil-water interface, which was turned to form stable HIPE gels. In addition, the resulted HIPE gels exhibited shear thinning behavior, viscoelastic features, and good thixotropic recovery, which provide a similar perceived texture and sensory property for formulating egg-free mayonnaise. These findings provide a useful approach to construct HIPE-based softs from low-cost wheat gluten for preparing plant-based mayonnaise.

A special focus on polyadenylation and alternative polyadenylation in neurodegenerative diseases: A systematic review

AbstractNeurodegenerative diseases (NDDs) are one of the prevailing conditions characterized by progressive neuronal loss. Polyadenylation (PA) and alternative polyadenylation (APA) are the two main post‐transcriptional events that regulate neuronal gene expression and protein production. This systematic review analyzed the available literature on the role of PA and APA in NDDs, with an emphasis on their contributions to disease development. A comprehensive literature search was performed using the PubMed, Scopus, Cochrane, Google Scholar, Embase, Web of Science, and ProQuest databases. The search strategy was developed based on the framework introduced by Arksey and O'Malley and supplemented by the inclusion and exclusion criteria. The study selection was performed by two independent reviewers. Extraction and data organization were performed in accordance with the predefined variables. Subsequently, quantitative and qualitative analyses were performed. Forty‐seven studies were included, related to a variety of NDDs, namely Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Disease induction was performed using different models, including human tissues, animal models, and cultured cells. Most investigations were related to PA, although some were related to APA or both. Amyloid precursor protein (APP), Tau, SNCA, and STMN2 were the major genes identified; most of the altered PA patterns were related to mRNA stability and translation efficiency. This review particularly underscores the key roles of PA and APA in the pathogenesis of NDDs through their mechanisms that contribute to gene expression dysregulation, protein aggregation, and neuronal dysfunction. Insights into these mechanisms may lead to new therapeutic strategies focused on the modulation of PA and APA activities. Further research is required to investigate the translational potential of targeting these pathways for NDD treatment. image

Co-Aggregation of TDP-43 with Other Pathogenic Proteins and Their Co-Pathologies in Neurodegenerative Diseases

Pathological aggregation of a specific protein into insoluble aggregates is a common hallmark of various neurodegenerative diseases (NDDs). In the earlier literature, each NDD is characterized by the aggregation of one or two pathogenic proteins, which can serve as disease-specific biomarkers. The aggregation of these specific proteins is thought to be a major cause of or deleterious result in most NDDs. However, accumulating evidence shows that a pathogenic protein can interact and co-aggregate with other pathogenic proteins in different NDDs, thereby contributing to disease onset and progression synergistically. During the past years, more than one type of NDD has been found to co-exist in some individuals, which may increase the complexity and pathogenicity of these diseases. This article reviews and discusses the biochemical characteristics and molecular mechanisms underlying the co-aggregation and co-pathologies associated with TDP-43 pathology. The TDP-43 aggregates, as a hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), can often be detected in other NDDs, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD) and spinocerebellar ataxia type 2 (SCA2). In many cases, TDP-43 is shown to interact and co-aggregate with multiple pathogenic proteins in vitro and in vivo. Furthermore, the co-occurrence and co-aggregation of TDP-43 with other pathogenic proteins have important consequences that may aggravate the diseases. Thus, the current viewpoint that the co-aggregation of TDP-43 with other pathogenic proteins in NDDs and their relevance to disease progression may gain insights into the patho-mechanisms and therapeutic potential of various NDDs.

Microglial Lyzl4 Facilitates β‐Amyloid Clearance in Alzheimer's Disease

AbstractAlzheimer's Disease (AD) is a neurodegenerative condition characterized by the accumulation and deposition of amyloid‐β (Aβ) aggregates in the brain. Despite a wealth of research on the toxicity of Aβ and its role in synaptic damage, the mechanisms facilitating Aβ clearance are not yet fully understood. However, microglia, the primary immune cells of the central nervous system, are known to maintain homeostasis through the phagocytic clearance of protein aggregates and cellular debris. In this study, RNA sequencing analysis and live cell functional screens are employed to uncover microglial genetic modifiers related to AD. Lyzl4 is identified, which encodes a c‐type lysozyme‐like enzyme primarily localized to microglial lysosomes, as a gene significantly upregulated in AD microglia with aging and propose that Lyzl4 upregulation acts as a positive regulator of Aβ clearance. Furthermore, it is found that Lyzl4 overexpression boosts Aβ clearance both in vitro and in vivo, underscoring its potential for mitigating Aβ burden. These novel insights position Lyzl4 as a promising therapeutic target for Alzheimer's disease, paving the way for further exploration into potential AD treatments.

Deciphering the Monomeric and Dimeric Conformational Landscapes of the Full-Length TDP-43 and the Impact of the C-Terminal Domain.

The aberrant aggregation of TAR DNA-binding protein 43 kDa (TDP-43) in cells leads to the pathogenesis of multiple fatal neurodegenerative diseases. Decoding the proposed initial transition between its functional dimeric and aggregation-prone monomeric states can potentially design a viable therapeutic strategy, which is presently limited by the lack of structural detail of the full-length TDP-43. To achieve a complete understanding of such a delicate phase space, we employed a multiscale simulation approach that unearths numerous crucial features, broadly summarized in two categories: (1) state-independent features that involve inherent chain collapsibility, rugged polymorphic landscape dictated by the terminal domains, high β-sheet propensity, structural integrity preserved by backbone-based intrachain hydrogen bonds and electrostatic forces, the prominence of the C-terminal domain in the intrachain cross-domain interfaces, and equal participation of hydrophobic and hydrophilic (charged and polar) residues in cross-domain interfaces; and (2) dimerization-modulated characteristics that encompass slower collapsing dynamics, restricted polymorphic landscape, the dominance of side chains in interchain hydrogen bonds, the appearance of the N-terminal domain in the dimer interface, and the prominence of hydrophilic (specifically polar) residues in interchain homo- and cross-domain interfaces. In our work, the ill-known C-terminal domain appears as the most crucial structure-dictating domain, which preferably populates a compact conformation with a high β-sheet propensity in its isolated state stabilized by intrabackbone hydrogen bonds, and these signatures are comparatively faded in its integrated form. Validation of our simulated observables by a complementary spectroscopic approach on multiple counts ensures the robustness of the computationally predicted features of the TDP-43 aggregation landscape.

Disulfide-mediated oligomerization of mutant Cu/Zn-superoxide dismutase associated with canine degenerative myelopathy.

A homozygous E40K mutation in the gene coding canine Cu/Zn-superoxide dismutase (cSOD1) causes degenerative myelopathy (DM) in dogs. A pathological hallmark of DM with the cSOD1 mutation is the aggregation of mutant cSOD1 proteins in neurons. The amino acid substitution E40K disrupts a salt bridge between Glu40 and Lys91 and is considered to destabilize the native state of cSOD1; however, the mechanism by which mutant cSOD1 aggregates remains unclear. Here, we show that mutant cSOD1 losing a copper and zinc ion forms oligomers crosslinked via disulfide bonds. The E40K substitution was found to result in the increased solvent exposure of the Cys7 side chain, which then attacked the disulfide bond (Cys57-Cys146) in cSOD1 to form disulfide-linked oligomers. We also successfully prevented the Cys7 exposure and thus the oligomerization of mutant cSOD1 by a fragment antibody that specifically recognizes the region around the mutation site. The fragment antibody covered the β-plug region, reinforcing the interactions compromised by the E40K substitution and thus contributing to the maintenance of the structural integrity of the β-barrel core of cSOD1. Taken together, we propose that the Cys7 exposure in cSOD1 upon the salt bridge disruption plays a central role in the aggregation mechanism of DM-associated mutant cSOD1.

Expanding the spectrum of HSPB8-related myopathy: a novel mutation causing atypical pediatric-onset axial and limb-girdle involvement with autophagy abnormalities and molecular dynamics studies.

Variants in HSPB8 are predominantly associated with peripheral neuropathies, but their occurrence in myopathies remains exceedingly rare. The genetic and clinical spectrum of HSPB8-related myopathy is not yet complete. Herein, we not only described the first Chinese case of HSPB8-related myopathy characterized by a novel heterozygous frameshift variant (c.576_579delinsCAG, p.Glu192Aspfs*55) in the C-terminal region of HSPB8, but also established the first association between this specific HSPB8 variant and pediatric-onset axial and limb-girdle myopathy. Muscle pathology revealed myofibrillar myopathy features and the novel pathological findings of inflammatory responses and vacuoles with sarcolemmal features pathology. Functional studies demonstrated significant colocalization of HSPB8 with autophagy markers and upregulation of autophagy-related proteins, which suggested that autophagic dysregulation may contribute to the pathological process of this disease. Furthermore, comprehensive bioinformatics analysis and molecular dynamics simulations revealed an increased propensity for aggregation, as well as altered structural and biochemical properties in the mutant HSPB8. Our study highlights the importance of considering HSPB8 mutations in early-onset axial and limb-girdle myopathy, expanding the genetic and phenotypic spectrum of the disease. Notably, our results underscore the critical role of autophagy dysregulation and aberrant protein aggregation in the pathogenesis, providing novel insights into potential therapeutic targets.

Diverse effects of fluorescent labels on alpha-synuclein condensate formation during liquid-liquid phase separation.

Liquid-liquid phase separation is an emerging field of study, dedicated to understanding the mechanism and role of biomolecule assembly into membraneless organelles. One of the main methods employed in studying protein and nucleic acid droplet formation is fluorescence microscopy. Despite functioning as an excellent tool for monitoring biomolecule condensation, a few recent reports have presented possible drawbacks of using fluorescently labeled particles. It was observed that fluorescent tags could alter the process of protein liquid-liquid phase separation and even promote their aggregation. In this study, we examined the influence of three different protein labels on alpha-synuclein phase separation in vitro and determined that the changes in droplet formation were related to both the type, as well as concentration of the fluorescently tagged alpha-synuclein. Both protein-based labels (mCherry and eGFP) induced the formation of significantly larger droplets, while fluorescein-tagged alpha-synuclein generated an abundance of small condensates or noticeably inhibited the process of LLPS. The study also revealed that alpha-synuclein with protein-based labels could self-associate at much lower concentrations than its untagged counterpart, forming either large droplets or protein aggregates.

Stabilizing Metal Coating on Flexible Devices by Ultrathin Protein Nanofilms.

The significant modulus difference between a metal coating and a polymer substrate leads to interface mismatches, seriously affecting the stability of flexible devices. Therefore, enhancing the adhesion stability of a metal layer on an inert polymer substrate to prevent delamination becomes a key challenge. Herein, an ultrathin protein nanofilm (UPN), synthesized by disulfide-bond-reducing protein aggregation, is proposed as a strong adhesive layer to enhance adhesion between polymer substrate and metal coating. Unlike traditional biopolymer adhesives with micrometer-scale thicknesses, the UPN layer is minimized to nanometer/single-molecular scale. Such UPN thereby effectively enhances the interfacial adhesive strength and reduces the cohesion contribution in the entire adhesion system by directly connecting two interfaces with a nearly single-molecular thickness. Using UPN as the adhesive layer, a multifunctional metal coating could be reliably adhered on flexible polymer substrates by ion sputtering, delivering unprecedented adhesion stability even under repetitive mechanical deformation. Applications of this design include reversible transparency control, tension-responsive encryption, reusable optical sensing, and wearable capacitive touch sensors. This work highlights UPN's potential to create strong bonding strength between flexible polymers and metal coatings, offering a biocompatible solution with high surface activity and low cohesion, facilitating the development of hybrid devices with stable metal nano-coating.

Site-selectively Phosphorylated Hsp90 C-terminal Domain Variants Provide Access to Deciphering the Chaperone Code.

The ubiquitous molecular chaperone Heat shock protein 90 (Hsp90) is pivotal in many cellular processes through folding of client proteins under stressed and normal conditions. Despite intensive research on its function as a chaperone, the influence of posttranslational modifications on Hsp90 (the 'chaperone code'), and its interactions with co-chaperones and client proteins, still remains to be elucidated. The C-terminal domain (CTD) of Hsp90 is essential for formation of the active homodimer state of Hsp90 and contains recognition sites for co-chaperones and client proteins. Here we used expressed protein selenoester ligation to introduce site-selective phosphorylations in the Hsp90 CTD, while preserving the native amino acid sequence. The two phosphorylations do not affect the overall secondary structure, but in combination, slightly decrease the thermal stability of the CTD. The Hsp90 CTD functions as a chaperone in decreasing aggregation of model client proteins, but the C-terminal phosphorylations do not significantly alter the anti-aggregation activity for these clients. The optimization of expressed protein selenoester ligation to carry out several steps in one pot provides an efficient route to access site-specifically modified Hsp90 CTD variants, allowing the generation of Hsp90 variants with site-specific PTMs to decipher the chaperone code.

Enzyme stabilisation due to incorporation of a fluorinated non-natural amino acid at the protein surface.

We have previously engineered E. coli transketolase (TK) enzyme variants that accept new substrates such as aliphatic or aromatic aldehydes, and also with improved thermal stability. Irreversible aggregation is the primary mechanism of deactivation for TK in the buffers used for biocatalysis, and so we were interested in determining the extent to which this remains true in more complex media, crude cell lysates or even in vivo. Such understanding would better guide future protein engineering efforts. NMR offers a potential approach to probe protein structure changes, aggregation, and diffusion, and19F-labelled amino acids are a useful NMR probe for complex systems with little or no background signal from the rest of the protein or their environment. Here we labelled E. coli TK with two different19F probes, trifluoromethyl-L-phenylalanine (tfm-Phe), and 4-fluoro phenylalanine (4F-Phe), through site specific non-natural amino acid incorporation. We targeted them to residue K316, a highly solvent exposed site located at the furthest point from the enzyme active sites. Characterisation of the19F-labelled TK variants revealed surprising effects of these mutations on stability, and to some extent on activity. While variant TK-tfm-Phe led to a 7.5°C increase in the thermal transition midpoint (Tm) for denaturation, the TK-4F-Phe variant largely abolished the aggregation of the enzyme when incubated at 50°C19. F-NMR revealed different behaviours in response to temperature increases for the two TK variants, displaying opposite temperature gradient chemical shifts, and diverging motion regimes, suggesting that the mutations affected differently both the local environment at this site, and its temperature-induced dynamics. A similar incubation of TK at 40-55°C is also known to induce higher cofactor-binding affinities, leading to an apparent heat activation under low cofactor concentration conditions. We have hypothesised previously that a heat-inducible conformational change in TK leads to this effect1. H-NMR revealed a temperature-dependent re-structuring of methyl groups, also at 30-50°C, which may be linked to the heat activation. While our kinetic studies were not expected to observe the heat activation event due to the high cofactor concentrations used, this was not the case for TK-4F-Phe, which did appear to heat activate slightly at 45°C. This implied that the mutations at K316 could influence cofactor-binding, despite their location at 47 Å from either active site. Such long-distance effects of mutations are not unprecedented, and indeed we have previously shown how distant mutations can influence active-site loop stability and function in TK, mediated via dynamically coupled networks of residues. Molecular dynamics simulations of the two19F containing variants similarly revealed networks of residues that could couple the changes in dynamics at residue K316, through to changes in active site dynamics. These results independently highlight the sensitivity of active-site function to distant mutations coupled through correlated dynamic networks of residues. They also highlight the potential influence of surface-incorporated probes on protein stability and function, and the need to characterise them well prior to further studies.

Phytochemicals in Parkinson's Disease: a Pathway to Neuroprotection and Personalized Medicine.

Parkinson's disease (PD) is a complex neurodegenerative disorder marked by the progressive loss of dopaminergic neurons in the substantia nigra. While current treatments primarily manage symptoms, there is increasing interest in alternative approaches, particularly the use of phytochemicals from medicinal plants. These natural compounds have demonstrated promising neuroprotective potential in preclinical studies by targeting key pathological mechanisms such as oxidative stress, neuroinflammation, and protein aggregation. However, the clinical translation of these phytochemicals is limited due to a lack of robust clinical trials evaluating their safety, efficacy, and pharmacokinetics. This review provides a comprehensive overview of the neuroprotective potential of phytochemicals in PD management, examining the mechanisms underlying PD pathogenesis and emphasizing neuroprotection. It explores the historical and current research on medicinal plants like Mucuna pruriens, Curcuma longa, and Ginkgo biloba, and discusses the challenges in clinical translation, including ethical and practical considerations and the integration with conventional therapies. It further underscores the need for future research to elucidate mechanisms of action, optimize drug delivery, and conduct rigorous clinical trials to establish the safety and efficacy of phytochemicals, aiming to shape future neuroprotective strategies and develop more effective, personalized treatments for PD.

Characterization of variably protease-sensitive prionopathy by capillary electrophoresis.

Variably Protease Sensitive Prionopathy (VPSPr) is a rare human prion disease that, like Creutzfeldt-Jakob disease (CJD), results in the deposition of abnormally folded prion protein aggregates in the brain and is ultimately fatal. Neuropathology and clinical features of VPSPr are heterogeneous. However, the key discriminating feature is the relative sensitivity of the pathological prion protein to proteinase digestion compared to that typically seen in other human prion cases. Three major fragments of 23, 17 and 7kDa are characteristic of the disease following digestion with proteinase K. We recently reported the utility of the highly adaptive and reproducible ProteinSimple™ capillary electrophoresis (CE) system to perform protein separation of PK digested prion protein in CJD. Consequently, we explored capillary-based electrophoresis (CE) technology as a sensitive method to detect and characterize VPSPr in a cohort of 29 cases. The unique 7kDa fragment has high intensity, particularly in cases with the codon 129 VV genotype, but can be missed by regular Western blotting due to the small size. However, this fragment is readily detected by CE in all cases. In addition, the flexibility of CE produced highly reproducible, semi-quantitative data for determining relative proteinase K sensitivity and epitope mapping of representative cases from each codon 129 genotype (VV, MV and MM).

Targeting Glucose Metabolism: A Novel Therapeutic Approach for Parkinson’s Disease

Glucose metabolism is essential for the maintenance and function of the central nervous system. Although the brain constitutes only 2% of the body weight, it consumes approximately 20% of the body’s total energy, predominantly derived from glucose. This high energy demand of the brain underscores its reliance on glucose to fuel various functions, including neuronal activity, synaptic transmission, and the maintenance of ion gradients necessary for nerve impulse transmission. Increasing evidence shows that many neurodegenerative diseases, including Parkinson’s disease (PD), are associated with abnormalities in glucose metabolism. PD is characterized by the progressive loss of dopaminergic neurons in the substantia nigra, accompanied by the accumulation of α-synuclein protein aggregates. These pathological features are exacerbated by mitochondrial dysfunction, oxidative stress, and neuroinflammation, all of which are influenced by glucose metabolism disruptions. Emerging evidence suggests that targeting glucose metabolism could offer therapeutic benefits for PD. Several antidiabetic drugs have shown promise in animal models and clinical trials for mitigating the symptoms and progression of PD. This review explores the current understanding of the association between PD and glucose metabolism, emphasizing the potential of antidiabetic medications as a novel therapeutic approach. By improving glucose uptake and utilization, enhancing mitochondrial function, and reducing neuroinflammation, these drugs could address key pathophysiological mechanisms in PD, offering hope for more effective management of this debilitating disease.

Exploring the interaction between the gut microbiota and cyclic adenosine monophosphate-protein kinase A signaling pathway: a potential therapeutic approach for neurodegenerative diseases

The interaction between the gut microbiota and cyclic adenosine monophosphate (cAMP)- protein kinase A (PKA) signaling pathway in the host's central nervous system plays a crucial role in neurological diseases and enhances communication along the gut–brain axis. The gut microbiota influences the cAMP-PKA signaling pathway through its metabolites, which activates the vagus nerve and modulates the immune and neuroendocrine systems. Conversely, alterations in the cAMP-PKA signaling pathway can affect the composition of the gut microbiota, creating a dynamic network of microbial-host interactions. This reciprocal regulation affects neurodevelopment, neurotransmitter control, and behavioral traits, thus playing a role in the modulation of neurological diseases. The coordinated activity of the gut microbiota and the cAMP-PKA signaling pathway regulates processes such as amyloid-β protein aggregation, mitochondrial dysfunction, abnormal energy metabolism, microglial activation, oxidative stress, and neurotransmitter release, which collectively influence the onset and progression of neurological diseases. This study explores the complex interplay between the gut microbiota and cAMP-PKA signaling pathway, along with its implications for potential therapeutic interventions in neurological diseases. Recent pharmacological research has shown that restoring the balance between gut flora and cAMP-PKA signaling pathway may improve outcomes in neurodegenerative diseases and emotional disorders. This can be achieved through various methods such as dietary modifications, probiotic supplements, Chinese herbal extracts, combinations of Chinese herbs, and innovative dosage forms. These findings suggest that regulating the gut microbiota and cAMP-PKA signaling pathway may provide valuable evidence for developing novel therapeutic approaches for neurodegenerative diseases.