Natural compound safranal driven inhibition and dis-aggregation of α-synuclein fibrils

Safranal acts as a neurorestorative agent in rats with cerebral ischemic stroke via upregulating SIRT1

Safranal is an active ingredient of saffron (Crocus sativus L.). Its neuroprotective role in ischemic stroke (IS) through reducing oxidative stress damage has been widely reported. However, the neurorestorative mechanisms of safranal are still in the preliminary stage of exploration. the present study is aimed to discuss the effects of safranal on the recovery of neural function after IS. A middle cerebral artery occlusion/reperfusion (MCAO/R) rat model and an oxygen-glucose deprivation/reoxygenation (OGD/R) model in rat brain microvascular endothelial cells (RBMEC) were established to explore the effects of safranal on IS in vivo and in vitro. It was found that safranal dramatically reduced infarct size and Nissl's body loss in rats subjected to MCAO/R. Safranal also promoted neuron survival, stimulated neurogenesis, induced angiogenesis and increased SIRT1 expression in vivo and in vitro. Silencing of SIRT1 reversed the above effects of safranal on OGD/R-induced RBMEC. The present study indicated that safranal was a promising compound to exert neurorestorative effect in IS via upregulating SIRT1 expression. These results offer insight into developing new mechanisms in the recovery of neural function after safranal treatment of IS.

Brazilin-7-acetate, a novel potential drug of Parkinson's disease, hinders the formation of α-synuclein fibril, mitigates cytotoxicity, and decreases oxidative stress

Parkinson's disease (PD) is a prevalent neurodegenerative disorder characterized by the accumulation of α-synuclein (α-Syn) aggregates. However, there are currently no effective therapies for PD. Brazilin, an inhibitor of α-Syn aggregation, is unstable and toxic. Therefore, we have developed and synthesized derivatives of brazilin. One of these derivatives, called brazilin-7-acetate (B-7-A), has shown reduced toxicity and a stronger effect on inhibiting α-Syn aggregation. It showed that B-7-A prevented the formation of α-Syn fibers and disrupted existing fibers in a dosage-dependent manner. Additionally, B-7-A significantly reduced the cytotoxicity of α-Syn aggregates and alleviated oxidative stress in PC12 cells. The beneficial effects of B-7-A were also confirmed using the Caenorhabditis elegans model. These effects included preventing the accumulation of α-Syn clumps, improving behavior disorder, increasing lifespan, reducing oxidative stress, and protecting against lipid oxidation and loss. Finally, B-7-A showed good ADMET properties in silico. Based on these findings, B-7-A exhibits potential as a prospective treatment for PD.

A guide to studying protein aggregation

Disrupted protein folding or decreased protein stability can lead to the accumulation of (partially) un- or misfolded proteins, which ultimately cause the formation of protein aggregates. Much of the interest in protein aggregation is associated with its involvement in a wide range of human diseases and the challenges it poses for large-scale biopharmaceutical manufacturing and formulation of therapeutic proteins and peptides. On the other hand, protein aggregates can also be functional, as observed in nature, which triggered its use in the development of biomaterials or therapeutics as well as for the improvement of food characteristics. Thus, unmasking the various steps involved in protein aggregation is critical to obtain a better understanding of the underlying mechanism of amyloid formation. This knowledge will allow a more tailored development of diagnostic methods and treatments for amyloid-associated diseases, as well as applications in the fields of new (bio)materials, food technology and therapeutics. However, the complex and dynamic nature of the aggregation process makes the study of protein aggregation challenging. To provide guidance on how to analyse protein aggregation, in this review we summarize the most commonly investigated aspects of protein aggregation with some popular corresponding methods.

Engineered graphene quantum dot nanocomposite triggers α-synuclein defibrillation: Therapeutics against Parkinson's disease

Emerging clinically required α-synuclein (α-syn) inhibitor which acts as a neuroprotective nanocomposite drug is in increased demand as a patient-safe central nervous system therapeutic. This inhibitor is intended to chemically engineer graphene quantum dot (GQD) with blue luminescence, and stands to be a potential cure for Parkinson's disease. It has been theorized that α-syn aggregation is a critical step in the development of Parkinson's. Hence narrow the target by α-syn inhibition, through chemically synthesize methyl N-allyl N-benzoylmethioninate (MABM) and functionally engineer the surface of GQD to target the brain delivery on C57BL/6 mice. Spectroscopic and simulation studies confirm defibrillation through the interaction between N-terminal amino acids and MABM-GQD nanoparticles, which makes nontoxic α-syn. Therefore, this drug's ability to cross the blood-brain barrier in vitro functionally prevents neuronal loss in neuroblastoma cells. Thus, in vivo cerebral blood flow analysis using magnetic resonance imaging illustrates, how this nanocomposite can possibly treat Parkinson's.

Pyrogallol, Corilagin and Chebulagic acid target the "fuzzy coat" of alpha-synuclein to inhibit the fibrillization of the protein

The accumulation of the intrinsically disordered protein alpha-synuclein (αSyn) in the form of insoluble fibrillar aggregates in the central nervous system is linked to a variety of neurodegenerative disorders such as Parkinson's disease, Lewy body dementia, and multiple system atrophy. Here we show that Pyrogallol, Corilagin and Chebulagic acid, compounds containing a different number of catechol rings, are independently capable of delaying and reducing the extent of αSyn fibrillization. The efficiency of inhibition was found to correlate with the number of catechol rings. Further, our NMR studies reveal that these compounds interact with the N-terminal region of αSyn which is unstructured even in the fibrillar form of the protein and is known as the "fuzzy coat" of fibrils. Thus, Corilagin and Chebulagic acid target the fuzzy coat of αSyn and not the amyloid core which is a common target for the inhibition of protein fibrillization. Our results indicate that the N-terminus also plays a key role in the fibrillization of αSyn.

Improving Aroma Complexity with Hanseniaspora spp.: Terpenes, Acetate Esters, and Safranal

Hanseniaspora vineae and Hanseniaspora opuntiae are apiculate yeasts normally found on the skins of ripe grapes and at the beginning of alcoholic fermentation. Several studies have reported that these species can provide interesting sensory characteristics to wine by contributing high levels of acetate esters and can increase the mouthfeel and body of wines. The present work aims to evaluate the use of these two species sequentially with Saccharomyces cerevisiae to improve the sensory profile of Albillo Mayor white wines. The fermentations were carried out in triplicate in 150 L stainless steel barrels. At the end of the alcoholic fermentation polysaccharides, colour, and an extensive study of the aromatic profiles were measured. Results showed up to 1.55 times higher content of 2-phenylethanol in H. opuntiae wines and up to three times higher concentration of fermentative esters in H. vineae wines than in the controls. Interestingly, it should be noted that the compound safranal was identified only in the H. vineae wines. These results indicated that the species studied are an interesting bio-tool to improve the aromatic profile of Albillo Mayor white wines. A novel non-targeted NMR-based metabolomics approach is proposed as a tool for optimising wine productions with standard and sequential fermentation schemes using apiculate yeast strains due to its discriminant capacity to differentiate fine features between wine samples from the identical geographical origin and grape variety but diverse fermentations or vintages.

Intrinsically Disordered Proteins: An Overview

Many proteins and protein segments cannot attain a single stable three-dimensional structure under physiological conditions; instead, they adopt multiple interconverting conformational states. Such intrinsically disordered proteins or protein segments are highly abundant across proteomes, and are involved in various effector functions. This review focuses on different aspects of disordered proteins and disordered protein regions, which form the basis of the so-called "Disorder-function paradigm" of proteins. Additionally, various experimental approaches and computational tools used for characterizing disordered regions in proteins are discussed. Finally, the role of disordered proteins in diseases and their utility as potential drug targets are explored.

Hybrids of polyphenolic acids and xanthone, the potential preventive and therapeutic effects on PD: Design, synthesis, in vitro anti-aggregation of α-synuclein, and disaggregation against the existed α-synuclein oligomer and fibril

The misfolding and aggregation of α-Syn are the central mechanism linking and facilitating the other pathological mechanisms of PD. Maintaining α-Syn proteostasis by suitable inhibitors is an effective means to prevent PD. Disintegrating the neurotoxic oligomers and fibrils into the normal functional α-Syn by inhibitors is a more efficient way for PD treatment. This work synthesized two series hybrids of polyphenolic acids and xanthone. The hybrids possess a sheet-like conjugated skeleton and higher binding energies with α-Syn residues. Some compounds present well α-Syn aggregation inhibitory activities in vitro (IC₅₀ down to 2.58 μM). The inhibitory action goes throughout the aggregation process from lag to the stationary phase by stabilizing α-Syn proteostasis conformation and preventing β-sheets aggregation. The candidate compounds with appropriate LogP values (2.02-3.11) present good disintegration abilities against the existed α-Syn oligomers and fibrils. The preliminary mechanism studies suggest that the inhibitors could quickly and randomly bind to the specific site closed to the β-sheet domain in the fibril, resulting in unstable and collapse of the protein fibril, yielding a complex system with aggregates of different sizes and monomers.

Ulvan inhibits α-synuclein fibrillation and disrupts the mature fibrils: In vitro and in vivo studies

Misfolding and aggregation of α-synuclein (α-syn) play a key role in the pathogenesis of Parkinson's disease (PD). Herein, the inhibitory effect of ulvan on α-syn fibrillogenesis was studied using thioflavin T fluorescence and atomic force microscope assays. It is shown that ulvan could inhibit α-syn fibrillogenesis in a dose-dependent manner. Based on the circular dichroism results, it is found that ulvan delays greatly the conformational transition from its initial random coil to β-sheet rich structure. The protective effect of ulvan against celllular death induced by α-syn aggregates was investigated by MTT colorimetric and cellular staining methods. It is found that ulvan protects greatly PC12 cells from α-syn fibril-induced cytotoxicity. In addition, ulvan disaggregates preformed α-syn fibrils and reduces cytotoxicity in a dose-dependent manner. Thereafter, the inhibitory effects of ulvan against α-syn fibrillogenesis were probed using Caenorhabditis elegans model NL5901 expressing human α-syn. It is found that ulvan extends the lifespan of NL5901 and recovers the lipid deposition by reducing the accumulation of α-syn. Finally, the molecular interactions between ulvan and α-syn pentamer was also explored using molecular docking. These findings suggest that ulvan can be pursued as a novel candidate drug for treatment of PD.

Bis-chalcone polyphenols with potential preventive and therapeutic effects on PD: Design, synthesis and in vitro disaggregation activity against α-synuclein oligomers and fibrils

α-Syn fibrils, which are neurotoxic, play a key role in the development of PD. Maintaining α-Syn proteostasis by suitable molecule ligands is an effective approach to prevent aggregation. Disintegrating the existed oligomers and fibrils into individual α-Syn by small molecular compounds is a more efficient way to treat PD. This work designed and synthesized two series of bis-chalcone polyphenol compounds, which possess a sheet-like conjugated skeleton with stronger H-bonding, π-stacking, and hydrophobic interaction with α-Syn protein residues. Some compounds have shown high α-Syn aggregation inhibitory activities in vitro with IC₅₀ down to 0.64 μM. The inhibition goes throughout the aggregation process from the lag to the stationary phase by stabilizing α-Syn proteostasis conformation and preventing β-sheets aggregation, especially in the lag phase. In addition, the inhibitors present good disintegration abilities against the existed α-Syn oligomers and fibrils. The preliminary mechanism studies suggest that the inhibitors could quickly and randomly bind to the specific site closed to the β-sheet domain in the fibril, resulting in unstable and collapse of the protein fibril and yielding a complex system with aggregates of different sizes and monomers. The inhibitors, which could penetrate the blood-brain barrier, are expected to develop into the drug candidates for PD targeting α-Syn aggregation.

Molecular Mechanisms behind Safranal's Toxicity to HepG2 Cells from Dual Omics

The spice saffron (Crocus sativus) has anticancer activity in several human tissues, but the molecular mechanisms underlying its potential therapeutic effects are poorly understood. We investigated the impact of safranal, a small molecule secondary metabolite from saffron, on the HCC cell line HepG2 using untargeted metabolomics (HPLC–MS) and transcriptomics (RNAseq). Increases in glutathione disulfide and other biomarkers for oxidative damage contrasted with lower levels of the antioxidants biliverdin IX (139-fold decrease, p = 5.3 × 10⁵), the ubiquinol precursor 3-4-dihydroxy-5-all-trans-decaprenylbenzoate (3-fold decrease, p = 1.9 × 10⁻⁵), and resolvin E1 (−3282-fold decrease, p = 4⁵), which indicates sensitization to reactive oxygen species. We observed a significant increase in intracellular hypoxanthine (538-fold increase, p = 7.7 × 10⁻⁶) that may be primarily responsible for oxidative damage in HCC after safranal treatment. The accumulation of free fatty acids and other biomarkers, such as S-methyl-5′-thioadenosine, are consistent with safranal-induced mitochondrial de-uncoupling and explains the sharp increase in hypoxanthine we observed. Overall, the dual omics datasets describe routes to widespread protein destabilization and DNA damage from safranal-induced oxidative stress in HCC cells.

Mahalanobis distance correlation: A novel approach for quantitating changes in multidimensional NMR spectra in biological applications

We present here a novel protocol for quantitating changes in the NMR spectra, which is based on Mahalanobis statistics. In a two dimensional NMR spectrum, the various peaks are taken to represent a distribution, and the two chemical shifts along the orthogonal axes and the peak intensities constitute three observables. All these observables vary in a correlated manner. Taking account of these, the Mahalanobis distance (MD) reflects the distance of any chosen peak from the centre of the distribution. For quantitating changes in a particular spectrum (say A) with N peaks (altered protein NMR spectrum) with respect to a reference spectrum (say B) with M peaks (original protein NMR spectrum), a composite spectrum with N + M peaks is generated. A one-to-one correspondence between N MD values considering all the N peaks in A and the same N peaks in the composite spectrum (A + B) is calculated. The MD distance of corresponding peaks in two different distributions can be correlated to assess the changes in the spectra during the course of a biological phenomenon, or as a result of biomolecular interactions. We have demonstrated these ideas, first, using the ¹H-¹⁵N HSQC spectrum of Ubiquitin, and then application of these has been demonstrated for monitoring progression of fibrillation of the protein α-Synuclein, in absence and presence of safranal, a known inhibitor of fibrillation of the protein. The method is in general applicable to multidimensional NMR spectra, does not require extensive data collection, and allows quantitative assessment of spectral changes via a single parameter. We believe that the method will have wide ranging applications to monitor many biological phenomena, and will also be useful in an industrial environment for mass comparison of molecules in a rapid manner.

Discovery of Neuroprotective Agents Based on a 5-(4-Pyridinyl)-1,2,4-triazole Scaffold

Parkinson's disease (PD) is characterized by the death of dopaminergic neurons. The common histopathological hallmark in PD patients is the formation of intracellular proteinaceous accumulations. The main constituent of these inclusions is alpha-synuclein (α-syn), an intrinsically disordered protein that in pathological conditions creates amyloid aggregates that lead to neurotoxicity and neurodegeneration. The main goal of our study was to optimize our previously identified α-syn aggregation inhibitors of 5-(4-pyridinyl)-1,2,4-triazole chemotype in terms of in vivo efficacy. Our efforts resulted in the identification of ethyl 2-((4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)thio)acetate (15), which displayed the ability to prevent 1-methyl-4-phenyl-1,2,3,6-tetrahydropiridine-induced bradykinesia as well as to affect the levels of PD markers after the administration of the same neurotoxin. In addition to the in vivo evaluation, for the 5-(4-pyridinyl)-1,2,4-triazole-based compounds, we measured the prevention of the fibrillization process using light scattering and a ThT binding assay; these compounds have been shown to slightly reduce the α-syn aggregation.

One ring is sufficient to inhibit α-synuclein aggregation

Parkinson’s disease, the second most prevalent neurodegenerative disorder worldwide, is characterized by a progressive loss of dopaminergic neurons in substantia nigra pars compacta, causing motor symptoms. This disorder’s main hallmark is the formation of intraneuronal protein inclusions, named Lewy bodies and neurites. The major component of these arrangements is α-synuclein, an intrinsically disordered and soluble protein that, in pathological conditions, can form toxic and cell-to-cell transmissible amyloid structures. Preventing α-synuclein aggregation has attracted significant effort in the search for a disease-modifying therapy for Parkinson’s disease. Small molecules like SynuClean-D, epigallocatechin gallate, trodusquemine, or anle138b exemplify this therapeutic potential. Here, we describe a subset of compounds containing a single aromatic ring, like dopamine, ZPDm, gallic acid, or entacapone, which act as molecular chaperones against α-synuclein aggregation. The simplicity of their structures contrasts with the complexity of the aggregation process, yet the block efficiently α-synuclein assembly into amyloid fibrils, in many cases, redirecting the reaction towards the formation of non-toxic off-pathway oligomers. Moreover, some of these compounds can disentangle mature α-synuclein amyloid fibrils. Their simple structures allow structure-activity relationship analysis to elucidate the role of different functional groups in the inhibition of α-synuclein aggregation and fibril dismantling, making them informative lead scaffolds for the rational development of efficient drugs.

Targeting disorders in unstructured and structured proteins in various diseases

Intrinsically disordered proteins (IDPs) and intrinsically disordered protein regions (IDPRs) are proteins and protein segments that usually do not acquire well-defined folded structures even under physiological conditions. They are abundantly present and challenge the "one sequence-one structure-one function" theory due to a lack of stable secondary and/or tertiary structure. Due to conformational flexibility, IDPs/IDPRs can bind with multiple interacting partners with high-specificity and low-affinity and perform essential biological functions associated with signalling, recognition and regulation. Mis-functioning and mis-regulation of IDPs and IDPRs causes disorder in disordered proteins and disordered protein segments which results in numerous human diseases, such as cancer, Parkinson's disease (PD), Alzheimer's disease (AD), diabetes, metabolic disorders, systemic disorders and so on. Due to the strong connection of IDPs/IDPRs with human diseases they are considered potentential targets for drug therapy. Since they disobey the "one sequence-one structure-one function" concept, IDPs/IDPRs are complex systems for drug targeting. This review summarises various protein disorder diseases and different methods for therapeutic targeting of disordered proteins/segments. Targeting IDPs/IDPRs for diseases will open up a new era of rational drug design and drug discovery.

Caffeic acid for the prevention and treatment of Alzheimer's disease: The effect of lipid membranes on the inhibition of aggregation and disruption of Aβ fibrils

The onset of Alzheimer's disease (AD) is triggered by the aggregation of amyloid β (Aβ) peptides which leads to the formation of fibrils. Molecules that are able to inhibit fibrillation and/or disrupt fibrils have aroused interest for AD therapy. Fibrillation is a complex process highly dependent on the surrounding environment. One of the most relevant factors affecting Aβ aggregation is the presence of cellular membranes. Here, the ability of caffeic acid (CA) in preventing the Aβ_1-42 aggregation and disaggregating mature fibrils was evaluated in a membrane-like environment and in a bulk solution for comparison. To this end, liposomes were used as in vitro models of neuronal membranes. CA exhibited strong activity in inhibiting the fibrillation of Aβ_1-42 in the aqueous medium, which remained in the presence of liposomes. Furthermore, CA disrupted instantly preformed fibrils in the aqueous medium. However, the CA's disaggregating activity was disturbed by the presence of lipid membranes. Instead of being immediate, the CA's disaggregating activity increased over time. The moderate affinity of CA for the lipid bilayer may explain the distinct fibrils disaggregation profiles. These findings emphasize the therapeutic potential of CA in preventing and treating AD, thus justifying further investigations in animal models.

Ellagic Acid Modulates Uninduced as well as Mutation and Metal-Induced Aggregation of α-Synuclein: Implications for Parkinson's Disease

α-Synuclein (αS) is an intrinsically disordered protein whose aggregation and deposition in Lewy bodies is involved in the progression of Parkinson's disease (PD) and other related disorders. The aggregation process of αS is also triggered by mutations like A53T and E46K in the SNCA gene and disruption in metal-ion homeostasis. Currently, there is no obviating therapy available in the market that could effectively prevent the progression of the disease. In this backdrop, there exists an emerging need to consider naturally occurring polyphenols and flavonoids as potential therapeutic agents against PD. In this study, we demonstrate the modulatory effect of ellagic acid (EA) against wild-type as well as mutation and metal-induced aggregation of αS. Thioflavin T (ThT) fluorescence assay suggests that EA acts on the nucleation phase of αS fibrillization, thereby increasing the lag phase from 21.33 ± 3.01 to 48.20 ± 5.05 h and reducing the fibrils growth rate from 4.60 ± 2.06 to 0.890 ± 0.36 h^-1. 8-Anilino-1-naphthalene sulfonic acid (ANS), Congo red (CR), and intrinsic fluorescence studies indicate that the interaction of EA with αS facilitates the structural changes in the protein that lead to inhibition of fibril formation. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) images illustrate that the size of fibrils diminishes up to 100 nm in the presence of EA. Dot blot and seeding experiments put forward that EA directs the αS aggregation toward off-pathway fibrillization. Our 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay deciphers the role of EA in minimizing the αS fibril-induced toxicity, thereupon leading to an increase in cell viability. Also, EA attenuates both mutations as well as metal-induced αS fibrillization and disaggregates the preexisting fibrils. Additionally, computational studies elucidate that EA preferentially interacts with the N-terminal and NAC domain of αS. Hence, this work reveals the aggregation inhibition mechanism of EA and provides considerable therapeutic interventions against PD and related disorders.

Vitamin B12 Inhibits Aβ Fibrillation and Disaggregates Preformed Fibrils in the Presence of Synthetic Neuronal Membranes

The aggregation of amyloid β (Aβ) peptide with subsequent formation of fibrils which deposit in senile plaques is considered one of the key triggers of Alzheimer's disease (AD). Molecules targeting the inhibition of Aβ fibrillation and/or the disruption of Aβ fibrils are thus promising approaches for the medical prevention and treatment of AD. However, amyloid formation is a complex process strongly influenced by the cellular environment, such as cell membranes, which may affect the effectiveness of therapeutic molecules. In this study, the effect of the vitamin B12 (VB12) on the formation and disaggregation of Aβ_1-42 fibrils was investigated in the presence of artificial neuronal membranes mimicked by liposomes. Evidence showed that VB12 slows down the Aβ fibrillization and reduces the content of fibrils in aqueous solution. Moreover, the vitamin exhibited a strong ability to disrupt preformed fibrils. However, the presence of lipid vesicles compromised the VB12's antiamyloidogenic properties due to the competitive interaction of the vitamin with the lipid membrane and the Aβ peptide. Even so, VB12 was effective in inhibiting the fibril formation and disaggregating fibrils in the lipid membrane environment. Thereby, these results indicate that VB12 could be a promising molecule both for the prevention and cure of AD, thus warranting its study in animal models.

Safranal Alleviated OVA-Induced Asthma Model and Inhibits Mast Cell Activation

Introduction

Asthma is a chronic and recurring airway disease, which related to mast cell activation. Many compounds derived from Chinese herbal medicine has promising effects on stabilizing mast cells and decreasing inflammatory mediator production. Safranal, one of the active compounds from Crocus sativus, shows many anti-inflammatory properties. In this study, we evaluated the effect of safranal in ovalbumin (OVA)-induced asthma model. Furthermore, we investigate the effectiveness of safranal on stabilizing mast cell and inhibiting the production of inflammatory mediators in passive systemic anaphylaxis (PSA) model.

Methods

OVA-induced asthma and PSA model were used to evaluate the effect of safranal in vivo. Lung tissues were collected for H&E, TB, IHC, and PAS staining. ELISA were used to determine level of IgE and chemokines (IL-4, IL-5, TNF-α, and IFN-γ). RNA sequencing was used to uncovers genes that safranal regulate. Bone marrow-derived mast cells (BMMCs) were used to investigate the inhibitory effect and mechanism of safranal. Cytokine production (IL-6, TNF-α, and LTC₄) and NF-κB and MAPKs signaling pathway were assessed.

Results

Safranal reduced the level of serum IgE, the number of mast cells in lung tissue were decreased and Th1/Th2 cytokine levels were normalized in OVA-induced asthma model. Furthermore, safranal inhibited BMMCs degranulation and inhibited the production of LTC₄, IL-6, and TNF-α. Safranal inhibits NF-κB and MAPKs pathway protein phosphorylation and decreases NF-κB p65, AP-1 nuclear translocation. In the PSA model, safranal reduced the levels of histamine and LTC₄ in serum.

Conclusions

Safranal alleviates OVA-induced asthma, inhibits mast cell activation and PSA reaction. The possible mechanism occurs through the inhibition of the MAPKs and NF-κB pathways.

Inhibition of α-Synuclein Aggregation and Mature Fibril Disassembling With a Minimalistic Compound, ZPDm

Synucleinopathies are a group of disorders characterized by the accumulation of α-Synuclein amyloid inclusions in the brain. Preventing α-Synuclein aggregation is challenging because of the disordered nature of the protein and the stochastic nature of fibrillogenesis, but, at the same time, it is a promising approach for therapeutic intervention in these pathologies. A high-throughput screening initiative allowed us to discover ZPDm, the smallest active molecule in a library of more than 14.000 compounds. Although the ZPDm structure is highly related to that of the previously described ZPD-2 aggregation inhibitor, we show here that their mechanisms of action are entirely different. ZPDm inhibits the aggregation of wild-type, A30P, and H50Q α-Synuclein variants in vitro and interferes with α-Synuclein seeded aggregation in protein misfolding cyclic amplification assays. However, ZPDm distinctive feature is its strong potency to dismantle preformed α-Synuclein amyloid fibrils. Studies in a Caenorhabditis elegans model of Parkinson's Disease, prove that these in vitro properties are translated into a significant reduction in the accumulation of α-Synuclein inclusions in ZPDm treated animals. Together with previous data, the present work illustrates how different chemical groups on top of a common molecular scaffold can result in divergent but complementary anti-amyloid activities.

Rational design of small molecules able to inhibit α-synuclein amyloid aggregation for the treatment of Parkinson's disease

Parkinson’s disease is one of the most common neurodegenerative disorders in elderly age. One of the mechanisms involved in the neurodegeneration appears related to the aggregation of the presynaptic protein alpha synuclein (α-syn) into toxic oligomers and fibrils. To date, no highly effective treatment is currently available; therefore, there is an increasing interest in the search of new therapeutic tools. The modulation of α-syn aggregation represents an emergent and promising disease-modifying strategy for reducing or blocking the neurodegenerative process. Herein, by combining in silico and in vitro screenings we initially identified 3-(cinnamylsulfanyl)-5-(4-pyridinyl)-1,2,4-triazol-4-amine (3) as α-syn aggregation inhibitor that was then considered a promising hit for the further design of a new series of small molecules. Therefore, we rationally designed new hit-derivatives that were synthesised and evaluated by biological assays. Lastly, the binding mode of the newer inhibitors was predicted by docking studies.