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Keywords = pre-formed fibril

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17 pages, 5347 KiB  
Article
Soluble and Insoluble Lysates from the Human A53T Mutant α-Synuclein Transgenic Mouse Model Induces α-Synucleinopathy Independent of Injection Site
by Justin Barnes, Scott C. Vermilyea, Joyce Meints, Héctor Martell-Martinez and Michael K. Lee
Int. J. Mol. Sci. 2025, 26(13), 6254; https://doi.org/10.3390/ijms26136254 - 28 Jun 2025
Viewed by 422
Abstract
Pathological aggregation of α-synuclein (αS) is implicated in the pathogenesis of Parkinson’s disease (PD) and other α-synucleinopathies. The current view is that neuron-to-neuron spreading of αS pathology contributes to the progression of α-synucleinopathy. We used an A53T mutant human αS transgenic mouse model [...] Read more.
Pathological aggregation of α-synuclein (αS) is implicated in the pathogenesis of Parkinson’s disease (PD) and other α-synucleinopathies. The current view is that neuron-to-neuron spreading of αS pathology contributes to the progression of α-synucleinopathy. We used an A53T mutant human αS transgenic mouse model (TgA53T) to examine whether the site of pathogenic αS inoculation affects the pattern of neuropathology and whether soluble and insoluble fractions derived from crude pathogenic tissue lysates exhibit differential capacities to initiate αS pathology. To test whether the inoculation site impacts the ultimate spatial/temporal patterns of αS pathology, αS preformed fibrils (PFFs), or brain homogenates from TgA53T mice with α-synucleinopathy, were injected into the cortex/striatum, brainstem, or skeletal muscle. In all cases, inoculation of pathogenic αS induced end-stage motor dysfunction within ~100 days post-inoculation (dpi). Significantly, irrespective of the inoculation sites, the ultimate distribution of the αS pathology was like that seen in normally aged TgA53T mice at end-stage, indicating that the intrinsic neuronal vulnerability is a significant determinant in the induction of αS pathology, even when initiated by inoculation of pathogenic αS. Temporal analysis of brainstem-injected TgA53T mice show that initial αS pathology was seen by 30 days post-inoculation and inflammatory changes occur at later stages. In addition, we show that both highly soluble (S150) and insoluble (P150) fractions from end-stage TgA53T mice can seed de novo αS pathology in vivo. Moreover, the endoplasmic reticulum (ER)-enriched fraction from the TgA53T mice were highly pathogenic as the ER fraction induced αS pathology faster than other fractions when injected unilaterally into TgA53T mice. Our results suggest that multiple αS species from the brain can initiate the development of progressive αS pathology. Full article
(This article belongs to the Special Issue New Challenges of Parkinson’s Disease)
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18 pages, 8584 KiB  
Article
Comparative Analysis of Components Involved in the Synthesis of Cellulose in Agave Species
by María José García-Castillo, Yahaira de Jesús Tamayo-Ordóñez, María Concepción Tamayo-Ordóñez, Felipe Barredo-Pool, Luis Carlos Rodríguez-Zapata, Benjamin Abraham Ayíl-Gutiérrez, María Teresa Pulido-Salas and Lorenzo Felipe Sánchez-Teyer
Agronomy 2025, 15(6), 1435; https://doi.org/10.3390/agronomy15061435 - 12 Jun 2025
Viewed by 902
Abstract
The process of obtaining Agave L. fibers dates back to pre-Hispanic times, and although humans have obtained different products from this crop, to date, the impact of humans (artificial selection, domestication and intensive cultivation) on these species is unknown. In this study, the [...] Read more.
The process of obtaining Agave L. fibers dates back to pre-Hispanic times, and although humans have obtained different products from this crop, to date, the impact of humans (artificial selection, domestication and intensive cultivation) on these species is unknown. In this study, the expression of the CesA gene was evaluated in three species, namely, Agave L, A. sisalana Perrine and A. fourcroydes Lem. (Sac ki), both of which are used for fiber production, and Agave tequilana Weber. The results revealed that, compared with A. fourcroydes and A. tequilana, A. sisalana had a greater leaf area, a significantly greater cellulose content and a greater number of cellulose fibrils. In terms of cell organization, the number and size of sclerenchyma fibers were similar between A. sisalana and A. fourcroydes. However, the relative expression of the CesA gene was five times greater in A. fourcroydes than in A. sisalana and A. tequilana, in contrast with the number of copies in those genomes. In addition, the tertiary structure of the CESA protein in fiber-producing species was modeled, placing agaves in a group along with Populus, Linum, Corchorus and Boehmeria. The haplotype network analysis revealed that A. tequilana is closely grouped with species of the order Poales, unlike the rest of the fiber-producing agaves, which formed a unique cluster. These findings suggest that artificial selection by humans, for various purposes, has contributed to the specialization of genes associated with traits such as fiber production. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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18 pages, 5233 KiB  
Article
Retinoid X Receptor as a Therapeutic Target to Treat Neurological Disorders Associated with α-Synucleinopathy
by Assylbek Zhylkibayev, Christopher R. Starr, M. Iqbal Hossain, Sandeep Kumar, Shaida A. Andrabi, Maria B. Grant, Venkatram R. Atigadda, Marina S. Gorbatyuk and Oleg S. Gorbatyuk
Cells 2025, 14(10), 685; https://doi.org/10.3390/cells14100685 - 9 May 2025
Viewed by 861
Abstract
This study investigated the therapeutic potential of the nuclear retinoid X receptor (RXR) in mitigating the progression of alpha-synucleinopathies (αSNPs), particularly in Parkinson’s disease (PD). PD-like pathology in mice was successfully induced through the co-delivery of AAV expressing human α-synuclein (αS) and αS [...] Read more.
This study investigated the therapeutic potential of the nuclear retinoid X receptor (RXR) in mitigating the progression of alpha-synucleinopathies (αSNPs), particularly in Parkinson’s disease (PD). PD-like pathology in mice was successfully induced through the co-delivery of AAV expressing human α-synuclein (αS) and αS preformed fibrils (PFFs) into the substantia nigra pars compacta (SNpc). Significant increases in Lewy body (LB)-like inclusions, loss of tyrosine hydroxylase-positive (TH+) neurons, and reductions in dopamine (DA) levels in the striatum were observed. Additionally, diminished levels of PPARα and NURR1—proteins essential for neuronal survival—along with elevated expression of IBA1 and GFAP, markers of microglial activation and astrocytic gliosis, respectively, are associated with the pathogenesis of Parkinson’s disease. AAV-mediated overexpression of human RXRα demonstrated preservation of TH+ neurons, prevention of DA decline, and attenuation of αS accumulation. Furthermore, RXR-treated PD brains showed a reduced number of GFAP+ and Iba1+ cells, decreased GFAP+ and IBA1+ immunoreactivity, and fewer and less widespread LB-like aggregates. RXR overexpression also enhanced the production of PPARα and NURR1. These findings suggest that RXRα upregulation promotes neuroprotection by mitigating αSNPs and chronic neuroinflammation, a major contributor to PD progression. This research underscores the therapeutic potential of targeting nuclear receptors, such as RXR, in neurodegenerative diseases like PD. Full article
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13 pages, 4494 KiB  
Article
A2-Astrocyte Activation by Short-Term Hypoxia Rescues α-Synuclein Pre-Formed-Fibril-Induced Neuronal Cell Death
by Ha Nyeoung Choi, Seon-Hee Kim, Min Gi Jo, Bina Lee, Young Jin Kim, So Eun Lee, Jeong Hyun Lee, Hye Min Seong, Seong Jae Kim, Sang Won Park, Hye Jung Kim, Heeyoung Kang, Chan Hyun Lee, Min Young Lee, Seung Pil Yun and Minkyeong Kim
Biomedicines 2025, 13(3), 604; https://doi.org/10.3390/biomedicines13030604 - 1 Mar 2025
Cited by 2 | Viewed by 1131
Abstract
Background/Objectives: Parkinson’s disease (PD) is a neuro-degenerative disease for which a radical cure is not available, only symptomatic control. Studies have shown that hypoxia may have disease-modifying effects on PD. Methods: Herein, we investigated whether short-term hypoxia activates astrocytes and whether it has [...] Read more.
Background/Objectives: Parkinson’s disease (PD) is a neuro-degenerative disease for which a radical cure is not available, only symptomatic control. Studies have shown that hypoxia may have disease-modifying effects on PD. Methods: Herein, we investigated whether short-term hypoxia activates astrocytes and whether it has a protective effect on pre-formed fibril (PFF)-treated primary cortical neurons. Results: Long-term hypoxia suppresses astrocyte activation and induces cell death, whereas short-term hypoxia activates astrocytes without affecting cellular apoptosis or viability. Short-term hypoxia restored the cellular apoptosis and viability of PFF-treated neurons and reduced toxic phospho-α-synuclein (p-α-syn) aggregation. Similarly, the short-term hypoxia-exposed astrocyte-conditioned medium rescued cellular apoptosis and the viability of PFF-treated neurons and p-α-syn expression. Quantitative polymerase chain reaction revealed that short-term hypoxia promotes protective A2 astrocytes and suppresses toxic A1 astrocytes. Conclusions: Our findings suggest that short-term hypoxia has a neuro-protective effect against PD by activating protective A2 astrocytes, which rescue PFF-induced neuronal cell death. This provides insights into the clinical implications of short-term hypoxia as a disease-modifying PD strategy. Full article
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19 pages, 6202 KiB  
Article
In Vitro Cell Model Investigation of Alpha-Synuclein Aggregate Morphology Using Spectroscopic Imaging
by Priyanka Swaminathan, Therése Klingstedt, Vasileios Theologidis, Hjalte Gram, Johan Larsson, Lars Hagen, Nina B. Liabakk, Odrun A. Gederaas, Per Hammarström, K. Peter R. Nilsson, Nathalie Van Den Berge and Mikael Lindgren
Int. J. Mol. Sci. 2024, 25(22), 12458; https://doi.org/10.3390/ijms252212458 - 20 Nov 2024
Cited by 2 | Viewed by 3671
Abstract
Recently, it has been hypothesized that alpha-synuclein protein strain morphology may be associated with clinical subtypes of alpha-synucleinopathies, like Parkinson’s disease and multiple system atrophy. However, direct evidence is lacking due to the caveat of conformation-specific characterization of protein strain morphology. Here we [...] Read more.
Recently, it has been hypothesized that alpha-synuclein protein strain morphology may be associated with clinical subtypes of alpha-synucleinopathies, like Parkinson’s disease and multiple system atrophy. However, direct evidence is lacking due to the caveat of conformation-specific characterization of protein strain morphology. Here we present a new cell model based in vitro method to explore various alpha-synuclein (αsyn) aggregate morphotypes. We performed a spectroscopic investigation of the HEK293 cell model, transfected with human wildtype-αsyn and A53T-αsyn variants, using the amyloid fibril-specific heptameric luminescent oligomeric thiophene h-FTAA. The spectral profile of h-FTAA binding to aggregates displayed a blue-shifted spectrum with a fluorescence decay time longer than in PBS, suggesting a hydrophobic binding site. In vitro spectroscopic binding characterization of h-FTAA with αsyn pre-formed fibrils suggested a binding dissociation constant Kd < 100 nM. The cells expressing the A53T-αsyn and human wildtype-αsyn were exposed to recombinant pre-formed fibrils of human αsyn. The ensuing intracellular aggregates were stained with h-FTAA followed by an evaluation of the spectral features and fluorescence lifetime of intracellular αsyn/h-FTAA, in order to characterize aggregate morphotypes. This study exemplifies the use of cell culture together with conformation-specific ligands to characterize strain morphology by investigating the spectral profiles and fluorescence lifetime of h-FTAA, based upon its binding to a certain αsyn aggregate. This study paves the way for toxicity studies of different αsyn strains in vitro and in vivo. Accurate differentiation of specific alpha-synucleinopathies is still limited to advanced disease stages. However, early subtype-specific diagnosis is of the utmost importance for prognosis and treatment response. The potential association of αsyn aggregates morphotypes detected in biopsies or fluids to disease phenotypes would allow for subtype-specific diagnosis in subclinical disease stage and potentially reveal new subtype-specific treatment targets. Notably, the method may be applied to the entire spectrum of neurodegenerative diseases by using a combination of conformation-specific ligands in a physicochemical environment together with other types of polymorphic amyloid variants and assess the conformation-specific features of various protein pathologies. Full article
(This article belongs to the Section Molecular Biology)
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28 pages, 7444 KiB  
Article
Exploring the Potential of Biomimetic Peptides in Targeting Fibrillar and Filamentous Alpha-Synuclein—An In Silico and Experimental Approach to Parkinson’s Disease
by Sophia A. Frantzeskos, Mary A. Biggs and Ipsita A. Banerjee
Biomimetics 2024, 9(11), 705; https://doi.org/10.3390/biomimetics9110705 - 18 Nov 2024
Viewed by 1703
Abstract
Alpha-synuclein (ASyn) is a protein that is known to play a critical role in Parkinson’s disease (PD) due to its propensity for misfolding and aggregation. Furthermore, this process leads to oxidative stress and the formation of free radicals that cause neuronal damage. In [...] Read more.
Alpha-synuclein (ASyn) is a protein that is known to play a critical role in Parkinson’s disease (PD) due to its propensity for misfolding and aggregation. Furthermore, this process leads to oxidative stress and the formation of free radicals that cause neuronal damage. In this study, we have utilized a biomimetic approach to design new peptides derived from marine natural resources. The peptides were designed using a peptide scrambling approach where antioxidant moieties were combined with fibrillary inhibition motifs in order to design peptides that would have a dual targeting effect on ASyn misfolding. Of the 20 designed peptides, 12 were selected for examining binding interactions through molecular docking and molecular dynamics approaches, which revealed that the peptides were binding to the pre-NAC and NAC (non-amyloid component) domain residues such as Tyr39, Asn65, Gly86, and Ala85, among others. Because ASyn filaments derived from Lewy body dementia (LBD) have a different secondary structure compared to pathogenic ASyn fibrils, both forms were tested computationally. Five of those peptides were utilized for laboratory validation based on those results. The binding interactions with fibrils were confirmed using surface plasmon resonance studies, where EQALMPWIWYWKDPNGS, PYYYWKDPNGS, and PYYYWKELAQM showed higher binding. Secondary structural analyses revealed their ability to induce conformational changes in ASyn fibrils. Additionally, PYYYWKDPNGS and PYYYWKELAQM also demonstrated antioxidant properties. This study provides insight into the binding interactions of varying forms of ASyn implicated in PD. The peptides may be further investigated for mitigating fibrillation at the cellular level and may have the potential to target ASyn. Full article
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24 pages, 1093 KiB  
Review
Role of NLRP3 Inflammasome in Heart Failure Patients Undergoing Cardiac Surgery as a Potential Determinant of Postoperative Atrial Fibrillation and Remodeling: Is SGLT2 Cotransporter Inhibition an Alternative for Cardioprotection?
by Rodrigo L. Castillo, Jorge Farías, Cristian Sandoval, Alejandro González-Candia, Esteban Figueroa, Mauricio Quezada, Gonzalo Cruz, Paola Llanos, Gonzalo Jorquera, Sawa Kostin and Rodrigo Carrasco
Antioxidants 2024, 13(11), 1388; https://doi.org/10.3390/antiox13111388 - 14 Nov 2024
Cited by 3 | Viewed by 3045
Abstract
In heart failure (HF) patients undergoing cardiac surgery, an increased activity of mechanisms related to cardiac remodeling may determine a higher risk of postoperative atrial fibrillation (POAF). Given that atrial fibrillation (AF) has a negative impact on the course and management of HF, [...] Read more.
In heart failure (HF) patients undergoing cardiac surgery, an increased activity of mechanisms related to cardiac remodeling may determine a higher risk of postoperative atrial fibrillation (POAF). Given that atrial fibrillation (AF) has a negative impact on the course and management of HF, including the need for anticoagulation therapy, identifying the factors associated with AF occurrence after cardiac surgery is crucial for the prognosis of these patients. POAF is thought to occur when various clinical and biochemical triggers act on susceptible cardiac tissue (first hit), with oxidative stress and inflammation during cardiopulmonary bypass (CPB) surgery being potential contributing factors (second hit). However, the molecular mechanisms involved in these processes remain poorly characterized. Recent research has shown that patients who later develop POAF often have pre-existing abnormalities in calcium handling and activation of NLRP3-inflammasome signaling in their atrial cardiomyocytes. These molecular changes may make cardiomyocytes more susceptible to spontaneous Ca2+-releases and subsequent arrhythmias, particularly when exposed to inflammatory mediators. Additionally, some clinical studies have linked POAF with elevated preoperative inflammatory markers, but there is a need for further research in order to better understand the impact of CPB surgery on local and systemic inflammation. This knowledge would make it possible to determine whether patients susceptible to POAF have pre-existing inflammatory conditions or cellular electrophysiological factors that make them more prone to developing AF and cardiac remodeling. In this context, the NLRP3 inflammasome, expressed in cardiomyocytes and cardiac fibroblasts, has been identified as playing a key role in the development of HF and AF, making patients with pre-existing HF with reduced ejection fraction (HFrEF) the focus of several clinical studies with interventions that act at this level. On the other hand, HFpEF has been linked to metabolic and non-ischemic risk factors, but more research is needed to better characterize the myocardial remodeling events associated with HFpEF. Therefore, since ventricular remodeling may differ between HFrEF and HFpEF, it is necessary to perform studies in both groups of patients due to their pathophysiological variations. Clinical evidence has shown that pharmacological therapies that are effective for HFrEF may not provide the same anti-remodeling benefits in HFpEF patients, particularly compared to traditional adrenergic and renin–angiotensin–aldosterone system inhibitors. On the other hand, there is growing interest in medications with pleiotropic or antioxidant/anti-inflammatory effects, such as sodium–glucose cotransporter 2 inhibitors (SGLT-2is). These drugs may offer anti-remodeling effects in both HFrEF and HFpEF by inhibiting pro-inflammatory, pro-oxidant, and NLRP3 signaling pathways and their mediators. The anti-inflammatory, antioxidant, and anti-remodeling effects of SGLT-2 i have progressively expanded from HFrEF and HFpEF to other forms of cardiac remodeling. However, these advances in research have not yet encompassed POAF despite its associations with inflammation, oxidative stress, and remodeling. Currently, the direct or indirect effects of NLRP3-dependent pathway inhibition on the occurrence of POAF have not been clinically assessed. However, given that NLRP3 pathway inhibition may also indirectly affect other pathways, such as inhibition of NF-kappaB or inhibition of matrix synthesis, which are strongly linked to POAF and cardiac remodeling, it is reasonable to hypothesize that this type of intervention could play a role in preventing these events. Full article
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18 pages, 5252 KiB  
Article
The Identification of Bioactive Compounds in the Aerial Parts of Agrimonia pilosa and Their Inhibitory Effects on Beta-Amyloid Production and Aggregation
by Chung Hyeon Lee, Min Sung Ko, Ye Seul Kim, Kwang Woo Hwang and So-Young Park
Separations 2024, 11(8), 243; https://doi.org/10.3390/separations11080243 - 9 Aug 2024
Viewed by 1587
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative condition characterized by memory and cognitive decline in older individuals. Beta-amyloid (Aβ), a significant component of senile plaques, is recognized as a primary contributor to AD pathology. Hence, substances that can inhibit Aβ [...] Read more.
Alzheimer’s disease (AD) is a progressive neurodegenerative condition characterized by memory and cognitive decline in older individuals. Beta-amyloid (Aβ), a significant component of senile plaques, is recognized as a primary contributor to AD pathology. Hence, substances that can inhibit Aβ production and/or accumulation are crucial for AD prevention and treatment. Agrimonia pilosa LEDEB. (A. pilosa) (Rosaceae), specifically its aerial parts, was identified in our previous screening study as a promising candidate with inhibitory effects on Aβ production. Therefore, in this study, A. pilosa extract was investigated for its anti-amyloidogenic effects, and its bioactive principles were isolated and identified. The ethanol extract of A. pilosa reduced the levels of sAPPβ and β-secretase by approximately 3% and 40%, respectively, compared to the DMSO-treated control group in APP-CHO cells (a cell line expressing amyloid precursor protein), which were similar to those in the positive control group. In addition, the ethanol extract of A. pilosa also hindered Aβ’s aggregation into fibrils and facilitated the disaggregation of Aβ aggregates, as confirmed by a Thioflavin T (Th T) assay. Subsequently, the active constituents were isolated using a bioassay-guided isolation method involving diverse column chromatography. Eleven compounds were identified—epi-catechin (1), catechin (2), (2S, 3S)-dihydrokaempferol 3-O-β-D-glucopyranoside (3), (-)-epiafzelechin 5-O-β-D-glucopyranoside (4), kaempferol 3-O-β-D-glucopyranoside (5), apigenin 7-O-β-D-glucopyranoside (6), dihydrokaempferol 7-O-β-D-glucopyranoside (7), quercetin 3-O-β-D-glucopyranoside (8), (2S, 3S)-taxifolin 3-O-β-D-glucopyranoside (9), luteolin 7-O-β-D-glucopyranoside (10), and apigenin 7-O-β-D-methylglucuronate (11)—identified through 1D and 2D NMR analysis and comparison with data from the literature. These compounds significantly decreased Aβ production by reducing β- and γ-secretase levels. Moreover, none of the compounds affected the expression levels of sAPPα or α-secretase. Further, compounds 1, 2, 4, 8, and 10 demonstrated a dose-dependent reduction in Aβ aggregation and promoted the disaggregation of pre-formed Aβ aggregates. Notably, compound 8 inhibited the aggregation of Aβ into fibrils by about 43% and facilitated the disassembly of Aβ aggregates by 41% compared to the control group containing only Aβ. These findings underscore the potential of A. pilosa extract and its constituents to mitigate a crucial pathological aspect of AD. Therefore, A. pilosa extract and its active constituents hold promise for development as therapeutics and preventatives of AD. Full article
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15 pages, 3613 KiB  
Article
Evaluation of the Effect of β-Wrapin AS69 in a Mouse Model Based on Alpha-Synuclein Overexpression
by Lennart Höfs, David Geißler-Lösch, Kristof M. Wunderlich, Eva M. Szegö, Chris Van den Haute, Veerle Baekelandt, Wolfgang Hoyer and Björn H. Falkenburger
Biomolecules 2024, 14(7), 756; https://doi.org/10.3390/biom14070756 - 25 Jun 2024
Cited by 1 | Viewed by 2032
Abstract
Aggregation of the protein α-Synuclein (αSyn) is a hallmark of Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and multiple systems atrophy, and alleviating the extent of αSyn pathology is an attractive strategy against neurodegeneration. The engineered binding protein β-wrapin AS69 binds monomeric [...] Read more.
Aggregation of the protein α-Synuclein (αSyn) is a hallmark of Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and multiple systems atrophy, and alleviating the extent of αSyn pathology is an attractive strategy against neurodegeneration. The engineered binding protein β-wrapin AS69 binds monomeric αSyn. AS69 reduces primary and secondary nucleation as well as fibril elongation in vitro. It also mitigates aSyn pathology in a mouse model based on intrastriatal injection of aSyn pre-formed fibrils (PFFs). Since the PFF-based model does not represent all aspects of PD, we tested here whether AS69 can reduce neurodegeneration resulting from αSyn overexpression. Human A53T-αSyn was overexpressed in the mouse Substantia nigra (SN) by using recombinant adeno-associated viral vector (rAAV). AS69 was also expressed by rAAV transduction. Behavioral tests and immunofluorescence staining were used as outcomes. Transduction with rAAV-αSyn resulted in αSyn pathology as reported by phospho-αSyn staining and caused degeneration of dopaminergic neurons in the SN. The co-expression of rAAV-AS69 did not reduce αSyn pathology or the degeneration of dopaminergic neurons. We conclude that αSyn monomer binding by rAAV-AS69 was insufficient to protect from aSyn pathology resulting from αSyn overexpression. Full article
(This article belongs to the Special Issue Synuclein Proteins, 2nd Edition)
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17 pages, 2267 KiB  
Article
Rheology of Suspensions of TEMPO-Oxidised and Cationic Cellulose Nanofibrils—The Effect of Chemical Pre-Treatment
by Luís Alves, Solange Magalhães, Jorge F. S. Pedrosa, Paulo J. T. Ferreira, José A. F. Gamelas and Maria Graça Rasteiro
Gels 2024, 10(6), 367; https://doi.org/10.3390/gels10060367 - 26 May 2024
Cited by 6 | Viewed by 1912
Abstract
Cellulose nanofibrils (CNFs) are particles with a high aspect ratio. Typically, chemically pre-treated CNFs (containing anionic or cationic charged groups) consist of long fibrils (up to 2 μm) with very low thickness (less than 10 nm). Derived from their high aspect ratio, CNFs [...] Read more.
Cellulose nanofibrils (CNFs) are particles with a high aspect ratio. Typically, chemically pre-treated CNFs (containing anionic or cationic charged groups) consist of long fibrils (up to 2 μm) with very low thickness (less than 10 nm). Derived from their high aspect ratio, CNFs form strong hydrogels with high elasticity at low concentrations. Thus, CNF suspensions appear as an interesting rheology modifier to be applied in cosmetics, paints, foods, and as a mineral suspending agent, among other applications. The high viscosity results from the strong 3D fibril network, which is related to the good fibrillation of the material, allowing the nanofibrils to overlap. The overlap concentration (c*) was found to vary from ca. 0.13 to ca. 0.60 wt.% depending on the type and intensity of the pre-treatment applied during the preparation of the CNFs. The results confirm the higher tendency for the fibres treated with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) to form a 3D network, resulting in the lowest c*. For the TEMPO-oxidised CNF suspensions, it was also found that aggregation is improved at acidic pH conditions due to lower charge repulsion among fibrils, leading to an increase in the suspension viscosity as well as higher apparent yield stresses. TEMPO CNF suspensions with a low content of carboxylic groups tend to precipitate at moderately acidic pH values. Full article
(This article belongs to the Special Issue Advances in Polymer Rheology)
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19 pages, 3398 KiB  
Article
4-Oxo-2-Nonenal- and Agitation-Induced Aggregates of α-Synuclein and Phosphorylated α-Synuclein with Distinct Biophysical Properties and Biomedical Applications
by Tie Wang, Weijin Liu, Qidi Zhang, Jie Jiao, Zihao Wang, Ge Gao and Hui Yang
Cells 2024, 13(9), 739; https://doi.org/10.3390/cells13090739 - 24 Apr 2024
Cited by 4 | Viewed by 1855
Abstract
α-Synuclein (α-syn) can form oligomers, protofibrils, and fibrils, which are associated with the pathogenesis of Parkinson’s disease and other synucleinopathies. Both the lipid peroxidation product 4-oxo-2-nonenal (ONE) and agitation can induce aggregation of α-syn and phosphorylated α-syn. Thus, clarification of the characteristics of [...] Read more.
α-Synuclein (α-syn) can form oligomers, protofibrils, and fibrils, which are associated with the pathogenesis of Parkinson’s disease and other synucleinopathies. Both the lipid peroxidation product 4-oxo-2-nonenal (ONE) and agitation can induce aggregation of α-syn and phosphorylated α-syn. Thus, clarification of the characteristics of different α-syn species could help to select suitable aggregates for diagnosis and elucidate the pathogenesis of diseases. Here, we characterized ONE-induced wild-type (WT) α-syn aggregates (OW), ONE-induced phosphorylated α-syn (p-α-syn) aggregates (OP), agitation-induced α-syn preformed fibrils (PFF), and agitation-induced p-α-syn preformed fibrils (pPFF). Thioflavin T (ThT) dying demonstrated that OW and OP had fewer fibrils than the PFF and pPFF. Transmission electron microscopy revealed that the lengths of PFF and pPFF were similar, but the diameters differed. OW and OP had more compact structures than PFF and pPFF. Aggregation of p-α-syn was significantly faster than WT α-syn. Furthermore, OW and OP were more sodium dodecyl sulfate-stable and proteinase K-resistant, suggesting greater stability and compactness, while aggregates of PFF and pPFF were more sensitive to proteinase K treatment. Both ONE- and agitation-induced aggregates were cytotoxic when added exogenously to SH-SY5Y cells with increasing incubation times, but the agitation-induced aggregates caused cell toxicity in a shorter time and more p-α-syn inclusions. Similarly, p-proteins were more cytotoxic than non-p-proteins. Finally, all four aggregates were used as standard antigens to establish sandwich enzyme-linked immunosorbent assay (ELISA). The results showed that the recognition efficiency of OW and OP was more sensitive than that of PFF and pPFF. The OW- and OP-specific ELISA for detection of p-α-syn and α-syn in plasma samples of Thy1-α-syn transgenic mice showed that the content of aggregates could reflect the extent of disease. ONE and agitation induced the formation of α-syn aggregates with distinct biophysical properties and biomedical applications. Full article
(This article belongs to the Section Cellular Pathology)
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21 pages, 3686 KiB  
Article
Characterization of pSer129-αSyn Pathology and Neurofilament Light-Chain Release across In Vivo, Ex Vivo, and In Vitro Models of Pre-Formed-Fibril-Induced αSyn Aggregation
by Maja L. Hansen, Malene Ambjørn, Mikkel N. Harndahl, Tau Benned-Jensen, Karina Fog, Kaare Bjerregaard-Andersen and Florence Sotty
Cells 2024, 13(3), 253; https://doi.org/10.3390/cells13030253 - 29 Jan 2024
Cited by 2 | Viewed by 2478
Abstract
Protein aggregation is a predominant feature of many neurodegenerative diseases, including synucleinopathies, which are characterized by cellular inclusions containing α-Synuclein (αSyn) phosphorylated at serine 129 (pSer129). In the present study, we characterized the development of αSyn pre-formed fibril (PFF)-induced pSer129-αSyn pathology in F28tg [...] Read more.
Protein aggregation is a predominant feature of many neurodegenerative diseases, including synucleinopathies, which are characterized by cellular inclusions containing α-Synuclein (αSyn) phosphorylated at serine 129 (pSer129). In the present study, we characterized the development of αSyn pre-formed fibril (PFF)-induced pSer129-αSyn pathology in F28tg mice overexpressing human wild-type αSyn, as well as in ex vivo organotypic cultures and in vitro primary cultures from the same mouse model. Concurrently, we collected cerebrospinal fluid (CSF) from mice and conditioned media from ex vivo and in vitro cultures and quantified the levels of neurofilament light chain (NFL), a biomarker of neurodegeneration. We found that the intra-striatal injection of PFFs induces the progressive spread of pSer129-αSyn pathology and microglial activation in vivo, as well as modest increases in NFL levels in the CSF. Similarly, PFF-induced αSyn pathology occurs progressively in ex vivo organotypic slice cultures and is accompanied by significant increases in NFL release into the media. Using in vitro primary hippocampal cultures, we further confirmed that pSer129-αSyn pathology and NFL release occur in a manner that correlates with the fibril dose and the level of the αSyn protein. Overall, we demonstrate that αSyn pathology is associated with NFL release across preclinical models of seeded αSyn aggregation and that the pharmacological inhibition of αSyn aggregation in vitro also significantly reduces NFL release. Full article
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14 pages, 3538 KiB  
Article
Combating Cariogenic Streptococcus mutans Biofilm Formation and Disruption with Coumaric Acid on Dentin Surface
by Syed Sohail Ahmad, Muhammad Faisal Siddiqui, Farhana Maqbool, Ihsan Ullah, Fazal Adnan, Aqel Albutti, Noorah Alsowayeh and Ziaur Rahman
Molecules 2024, 29(2), 397; https://doi.org/10.3390/molecules29020397 - 13 Jan 2024
Cited by 6 | Viewed by 4033
Abstract
Streptococcus mutans, the primary cause of dental caries, relies on its ability to create and sustain a biofilm (dental plaque) for survival and pathogenicity in the oral cavity. This study was focused on the antimicrobial biofilm formation control and biofilm dispersal potential [...] Read more.
Streptococcus mutans, the primary cause of dental caries, relies on its ability to create and sustain a biofilm (dental plaque) for survival and pathogenicity in the oral cavity. This study was focused on the antimicrobial biofilm formation control and biofilm dispersal potential of Coumaric acid (CA) against Streptococcus mutans on the dentin surface. The biofilm was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability assay, microtiter plate assay, production of extracellular polymeric substances (EPSs), florescence microscopy (surface coverage and biomass μm2) and three-dimensional (3D) surface plots. It was observed that CA at 0.01 mg/mL reduced bacterial growth by 5.51%, whereases at 1 mg/mL, a significant (p < 0.05) reduction (98.37%) was observed. However, at 1 mg/mL of CA, a 95.48% biofilm formation reduction was achieved, while a 73.45% biofilm dispersal (after 24 h. treatment) was achieved against the preformed biofilm. The MTT assay showed that at 1 mg/mL of CA, the viability of bacteria in the biofilm was markedly (p < 0.05) reduced to 73.44%. Moreover, polysaccharide (EPS) was reduced to 24.80 μg/mL and protein (EPS) to 41.47 μg/mL. ImageJ software (version 1.54 g) was used to process florescence images, and it was observed that the biofilm mass was reduced to 213 (μm2); the surface coverage was reduced to 0.079%. Furthermore, the 3D surface plots showed that the untreated biofilm was highly dense, with more fibril-like projections. Additionally, molecular docking predicted a possible interaction pattern of CA (ligand) with the receptor Competence Stimulating Peptide (UA159sp, PDB ID: 2I2J). Our findings suggest that CA has antibacterial and biofilm control efficacy against S. mutans associated with dental plaque under tested conditions. Full article
(This article belongs to the Special Issue Antimicrobial and Immunomodulatory Activities of Natural Products)
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18 pages, 3741 KiB  
Article
Splicing Modulation via Antisense Oligonucleotides in Recessive Dystrophic Epidermolysis Bullosa
by Stefan Hainzl, Lisa Trattner, Bernadette Liemberger, Johannes Bischof, Thomas Kocher, Michael Ablinger, Alexander Nyström, Astrid Obermayer, Alfred Klausegger, Christina Guttmann-Gruber, Verena Wally, Johann W. Bauer, Josefina Piñón Hofbauer and Ulrich Koller
Int. J. Mol. Sci. 2024, 25(2), 761; https://doi.org/10.3390/ijms25020761 - 7 Jan 2024
Cited by 4 | Viewed by 2592
Abstract
Antisense oligonucleotides (ASOs) represent an emerging therapeutic platform for targeting genetic diseases by influencing various aspects of (pre-)mRNA biology, such as splicing, stability, and translation. In this study, we investigated the potential of modulating the splicing pattern in recessive dystrophic epidermolysis bullosa (RDEB) [...] Read more.
Antisense oligonucleotides (ASOs) represent an emerging therapeutic platform for targeting genetic diseases by influencing various aspects of (pre-)mRNA biology, such as splicing, stability, and translation. In this study, we investigated the potential of modulating the splicing pattern in recessive dystrophic epidermolysis bullosa (RDEB) patient cells carrying a frequent genomic variant (c.425A > G) that disrupts splicing in the COL7A1 gene by using short 2′-O-(2-Methoxyethyl) oligoribo-nucleotides (2′-MOE ASOs). COL7A1-encoded type VII collagen (C7) forms the anchoring fibrils within the skin that are essential for the attachment of the epidermis to the underlying dermis. As such, gene variants of COL7A1 leading to functionally impaired or absent C7 manifest in the form of extensive blistering and wounding. The severity of the disease pattern warrants the development of novel therapies for patients. The c.425A > G variant at the COL7A1 exon 3/intron 3 junction lowers the efficiency of splicing at this junction, resulting in non-functional C7 transcripts. However, we found that correct splicing still occurs, albeit at a very low level, highlighting an opportunity for intervention by modulating the splicing reaction. We therefore screened 2′-MOE ASOs that bind along the COL7A1 target region ranging from exon 3 to the intron 3/exon 4 junction for their ability to modulate splicing. We identified ASOs capable of increasing the relative levels of correctly spliced COL7A1 transcripts by RT-PCR, sqRT-PCR, and ddPCR. Furthermore, RDEB-derived skin equivalents treated with one of the most promising ASOs exhibited an increase in full-length C7 expression and its accurate deposition along the basement membrane zone (BMZ). Full article
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14 pages, 2289 KiB  
Article
The Impact of Intestinal Microbiota and Toll-like Receptor 2 Signaling on α-Synuclein Pathology in Nontransgenic Mice Injected with α-Synuclein Preformed Fibrils
by Yukako Koyanagi, Momoe Kassai and Hiroshi Yoneyama
Microorganisms 2024, 12(1), 106; https://doi.org/10.3390/microorganisms12010106 - 5 Jan 2024
Cited by 1 | Viewed by 1770
Abstract
Intestinal microbiota and Toll-like receptor 2 (TLR2), which can bind lipoteichoic acid produced by microbiota, might contribute to the pathogenesis of Parkinson’s disease (PD), which is characterized by α-synuclein accumulation. Although the contribution of intestinal microbiota and TLR2 to PD pathology was validated [...] Read more.
Intestinal microbiota and Toll-like receptor 2 (TLR2), which can bind lipoteichoic acid produced by microbiota, might contribute to the pathogenesis of Parkinson’s disease (PD), which is characterized by α-synuclein accumulation. Although the contribution of intestinal microbiota and TLR2 to PD pathology was validated in genetic PD models, evidence suggests that the effects of TLR2 signaling on proteinopathy might depend on the presence of a genetic etiology. We examined the impact of intestinal microbiota and TLR2 signaling on α-synuclein pathology in a nontransgenic mouse model of sporadic PD. While an α-synuclein preformed fibrils injection successfully reproduced PD pathology by inducing accumulation of α-synuclein aggregates, microglial activation and increased TLR2 expression in the brains of nontransgenic mice, antibiotic-induced reduction in the density of intestinal microbiota and TLR2 knockout had small impact on these changes. These findings, which are in contrast to those reported in transgenic mice harboring transgene encoding α-synuclein, indicate that the contribution of intestinal microbiota and TLR2 signaling to α-synuclein pathogenesis might be influenced by the presence of a genetic etiology. Additionally, these findings suggest that integrating insights from this experimental model and genetic models would further advance our understanding of the molecular mechanisms underlying sporadic PD. Full article
(This article belongs to the Special Issue Effects of Gut Microbiota on Human Health and Disease)
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