The Amyloid Fibril-Forming β-Sheet Regions of Amyloid β and α-Synuclein Preferentially Interact with the Molecular Chaperone 14-3-3ζ

14-3-3 proteins are abundant, intramolecular proteins that play a pivotal role in cellular signal transduction by interacting with phosphorylated ligands. In addition, they are molecular chaperones that prevent protein unfolding and aggregation under cellular stress conditions in a similar manner to the unrelated small heat-shock proteins. In vivo, amyloid β (Aβ) and α-synuclein (α-syn) form amyloid fibrils in Alzheimer’s and Parkinson’s diseases, respectively, a process that is intimately linked to the diseases’ progression. The 14-3-3ζ isoform potently inhibited in vitro fibril formation of the 40-amino acid form of Aβ (Aβ₄₀) but had little effect on α-syn aggregation. Solution-phase NMR spectroscopy of ¹⁵N-labeled Aβ₄₀ and A53T α-syn determined that unlabeled 14-3-3ζ interacted preferentially with hydrophobic regions of Aβ₄₀ (L11-H21 and G29-V40) and α-syn (V3-K10 and V40-K60). In both proteins, these regions adopt β-strands within the core of the amyloid fibrils prepared in vitro as well as those isolated from the inclusions of diseased individuals. The interaction with 14-3-3ζ is transient and occurs at the early stages of the fibrillar aggregation pathway to maintain the native, monomeric, and unfolded structure of Aβ₄₀ and α-syn. The N-terminal regions of α-syn interacting with 14-3-3ζ correspond with those that interact with other molecular chaperones as monitored by in-cell NMR spectroscopy.     

Nanomaterials for Modulating the Aggregation of β-Amyloid Peptides

The aberrant aggregation of amyloid-β (Aβ) peptides in the brain has been recognized as the major hallmark of Alzheimer’s disease (AD). Thus, the inhibition and dissociation of Aβ aggregation are believed to be effective therapeutic strategiesforthe prevention and treatment of AD. When integrated with traditional agents and biomolecules, nanomaterials can overcome their intrinsic shortcomings and boost their efficiency via synergistic effects. This article provides an overview of recent efforts to utilize nanomaterials with superior properties to propose effective platforms for AD treatment. The underlying mechanismsthat are involved in modulating Aβ aggregation are discussed. The summary of nanomaterials-based modulation of Aβ aggregation may help researchers to understand the critical roles in therapeutic agents and provide new insight into the exploration of more promising anti-amyloid agents and tactics in AD theranostics.     

Beneficial Effects of Cyclic Ether 2-Butoxytetrahydrofuran from Sea Cucumber Holothuria scabra against Aβ Aggregate Toxicity in Transgenic Caenorhabditis elegans and Potential Chemical Interaction

The pathological finding of amyloid-β (Aβ) aggregates is thought to be a leading cause of untreated Alzheimer’s disease (AD). In this study, we isolated 2-butoxytetrahydrofuran (2-BTHF), a small cyclic ether, from Holothuria scabra and demonstrated its therapeutic potential against AD through the attenuation of Aβ aggregation in a transgenic Caenorhabditis elegans model. Our results revealed that amongst the five H. scabra isolated compounds, 2-BTHF was shown to be the most effective in suppressing worm paralysis caused by Aβ toxicity and in expressing strong neuroprotection in CL4176 and CL2355 strains, respectively. An immunoblot analysis showed that CL4176 and CL2006 treated with 2-BTHF showed no effect on the level of Aβ monomers but significantly reduced the toxic oligomeric form and the amount of 1,4-bis(3-carboxy-hydroxy-phenylethenyl)-benzene (X-34)-positive fibril deposits. This concurrently occurred with a reduction of reactive oxygen species (ROS) in the treated CL4176 worms. Mechanistically, heat shock factor 1 (HSF-1) (at residues histidine 63 (HIS63) and glutamine 72 (GLN72)) was shown to be 2-BTHF’s potential target that might contribute to an increased expression of autophagy-related genes required for the breakdown of the Aβ aggregate, thus attenuating its toxicity. In conclusion, 2-BTHF from H. scabra could protect C. elegans from Aβ toxicity by suppressing its aggregation via an HSF-1-regulated autophagic pathway and has been implicated as a potential drug for AD.     

Near-Wall Aggregation of Amyloidogenic Aβ 1-40 Peptide: Direct Observation by the FRET

The formation of amyloid fibrils is one of the variants of the self-organization of polypeptide chains. For the amyloid aggregation, the solution must be oversaturated with proteins. The interface of the liquid (solution) and solid (vessel walls) phases can trigger the adsorption of protein molecules, and the resulting oversaturation can initiate conformational transitions in them. In any laboratory experiment, we cannot exclude the presence of surfaces such as the walls of vessels, cuvettes, etc. However, in many works devoted to the study of amyloid formation, this feature is not considered. In our work, we investigated the behavior of the Aβ 1-40 peptide at the water–glass, water–quartz, and water–plastic interface. We carried out a series of simple experiments and showed that the Aβ 1-40 peptide is actively adsorbed on these surfaces, which leads to a significant interaction and aggregation of peptides. This means that the interface can be the place where the first amyloid nucleus appears. We suggest that this effect may also be one of the reasons for the difficulty of reproducing kinetic data when studying the aggregation of the amyloid of the Aβ 1-40 peptide and other amyloidogenic proteins     

Significance of Oligomeric and Fibrillar Species in Amyloidosis: Insights into Pathophysiology and Treatment

Amyloidosis is a term referring to a group of various protein-misfolding diseases wherein normally soluble proteins form aggregates as insoluble amyloid fibrils. How, or whether, amyloid fibrils contribute to tissue damage in amyloidosis has been the topic of debate. In vitro studies have demonstrated the appearance of small globular oligomeric species during the incubation of amyloid beta peptide (Aβ). Nerve biopsy specimens from patients with systemic amyloidosis have suggested that globular structures similar to Aβ oligomers were generated from amorphous electron-dense materials and later developed into mature amyloid fibrils. Schwann cells adjacent to amyloid fibrils become atrophic and degenerative, suggesting that the direct tissue damage induced by amyloid fibrils plays an important role in systemic amyloidosis. In contrast, there is increasing evidence that oligomers, rather than amyloid fibrils, are responsible for cell death in neurodegenerative diseases, particularly Alzheimer’s disease. Disease-modifying therapies based on the pathophysiology of amyloidosis have now become available. Aducanumab, a human monoclonal antibody against the aggregated form of Aβ, was recently approved for Alzheimer’s disease, and other monoclonal antibodies, including gantenerumab, solanezumab, and lecanemab, could also be up for approval. As many other agents for amyloidosis will be developed in the future, studies to develop sensitive clinical scales for identifying improvement and markers that can act as surrogates for clinical scales should be conducted.     

Synthesis and Characterization of Andrographolide Derivatives as Regulators of βAPP Processing in Human Cells

Alzheimer’s disease (AD) is a devastating neurodegenerative disorder, one of the main characteristics of which is the abnormal accumulation of amyloid peptide (Aβ) in the brain. Whereas β-secretase supports Aβ formation along the amyloidogenic processing of the β-amyloid precursor protein (βAPP), α-secretase counterbalances this pathway by both preventing Aβ production and triggering the release of the neuroprotective sAPPα metabolite. Therefore, stimulating α-secretase and/or inhibiting β-secretase can be considered a promising anti-AD therapeutic track. In this context, we tested andrographolide, a labdane diterpene derived from the plant Andrographis paniculata, as well as 24 synthesized derivatives, for their ability to induce sAPPα production in cultured SH-SY5Y human neuroblastoma cells. Following several rounds of screening, we identified three hits that were subjected to full characterization. Interestingly, andrographolide (8,17-olefinic) and its close derivative 14α-(5′,7′-dichloro-8′-quinolyloxy)-3,19-acetonylidene (compound 9) behave as moderate α-secretase activators, while 14α-(2′-methyl-5′,7′-dichloro-8′-quinolyloxy)-8,9-olefinic compounds 31 (3,19-acetonylidene) and 37 (3,19-diol), whose two structures are quite similar although distant from that of andrographolide and 9, stand as β-secretase inhibitors. Importantly, these results were confirmed in human HEK293 cells and these compounds do not trigger toxicity in either cell line. Altogether, these findings may represent an encouraging starting point for the future development of andrographolide-based compounds aimed at both activating α-secretase and inhibiting β-secretase that could prove useful in our quest for the therapeutic treatment of AD.     

Design and Synthesis of New Benzo[d]oxazole-Based Derivatives and Their Neuroprotective Effects on β-Amyloid-Induced PC12 Cells

A series of novel synthetic substituted benzo[d]oxazole-based derivatives (5a–5v) exerted neuroprotective effects on β-amyloid (Aβ)-induced PC12 cells as a potential approach for the treatment of Alzheimer’s disease (AD). In vitro studies show that most of the synthesized compounds were potent in reducing the neurotoxicity of Aβ_25-35-induced PC12 cells at 5 μg/mL. We found that compound 5c was non-neurotoxic at 30 μg/mL and significantly increased the viability of Aβ_25-35-induced PC12 cells at 1.25, 2.5 and 5 μg/mL. Western blot analysis showed that compound 5c promoted the phosphorylation of Akt and glycogen synthase kinase (GSK-3β) and decreased the expression of nuclear factor-κB (NF-κB) in Aβ_25-35-induced PC12 cells. In addition, our findings demonstrated that compound 5c protected PC12 cells from Aβ_25-35-induced apoptosis and reduced the hyperphosphorylation of tau protein, and decreased the expression of receptor for AGE (RAGE), β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1), inducible nitric oxide synthase (iNOS) and Bcl-2-associated X protein/B-cell lymphoma 2 (Bax/Bcl-2) via Akt/GSK-3β/NF-κB signaling pathway. In vivo studies suggest that compound 5c shows less toxicity than donepezil in the heart and nervous system of zebrafish.     

Ameliorating Effect on Aβ-Induced Alzheimer’s Mice by Litsea cubeba Persoon Powder

Alzheimer’s disease (AD) is caused by excessive oxidative damage and aging. The objective of this study was to investigate the anti-dementia effect of LCP fruit powder on amyloid β (Aβ)-induced Alzheimer’s mice. The composition of LCP essential oil was determined by gas chromatography/mass spectrometry. In addition, the water maze was used to evaluate the learning and memorizing abilities of the mice. The concentrations of malondialdehyde (MDA), protein carbonyl, phosphorylated τ-protein, and the deposition of Aβ plaques in mouse brains were also assessed. The results showed that the main components of essential oils in LCP and d-limonene, neral, and geranial contents were 14.15%, 30.94%, and 31.74%, respectively. Furthermore, oral administration with different dosages of LCP significantly decreased the escape time (21.25~33.62 s) and distance (3.23~5.07 m) in the reference memory test, and increased the duration time (26.14~28.90 s) and crossing frequency (7.00~7.88 times) in the target zone of probe test (p < 0.05). LCP also inhibited the contents of MDA and the phosphor-τ-protein from oxidative stress, reduced the brain atrophy by about 3~8%, and decreased the percentage of Aβ plaques from 0.44 to 0.05%. Finally, it was observed that the minimum dosage of LCP fruit powder (LLCP, 30.2 mg/day) could prevent oxidative stress induced by Aβ and subsequently facilitate memory and learning deficits in Aβ-induced neurotoxicity and cognitively impaired mice.     

Established Beta Amyloid Pathology Is Unaffected by TREM2 Elevation in Reactive Microglia in an Alzheimer’s Disease Mouse Model

Several genetic studies have identified a rare variant of triggering receptor expressed on myeloid cells 2 (TREM2) as a risk factor for Alzheimer’s disease (AD). However, findings on the effects of TREM2 on Aβ deposition are quite inconsistent in animal studies, requiring further investigation. In this study, we investigated whether elevation of TREM2 mitigates Aβ pathology in TgCRND8 mice. We found that peripheral nerve injury resulted in a robust elevation of TREM2 exclusively in reactive microglia in the ipsilateral spinal cord of aged TgCRND8 mice at the age of 20 months. TREM2 expression appeared on day 1 post-injury and the upregulation was maintained for at least 28 days. Compared to the contralateral side, neither amyloid beta plaque load nor soluble Aβ40 and Aβ42 levels were attenuated upon TREM2 induction. We further showed direct evidence that TREM2 elevation in reactive microglia did not affect amyloid-β pathology in plaque-bearing TgCRND8 mice by applying anti-TREM2 neutralizing antibody to selectively block TREM2. Our results question the ability of TREM2 to ameliorate established Aβ pathology, discouraging future development of disease-modifying pharmacological treatments targeting TREM2 in the late stage of AD.     

Implementing Complementary Approaches to Shape the Mechanism of α-Synuclein Oligomerization as a Model of Amyloid Aggregation

The aggregation of proteins into amyloid fibers is linked to more than forty still incurable cellular and neurodegenerative diseases such as Parkinson’s disease (PD), multiple system atrophy, Alzheimer’s disease and type 2 diabetes, among others. The process of amyloid formation is a main feature of cell degeneration and disease pathogenesis. Despite being methodologically challenging, a complete understanding of the molecular mechanism of aggregation, especially in the early stages, is essential to find new biological targets for innovative therapies. Here, we reviewed selected examples on α-syn showing how complementary approaches, which employ different biophysical techniques and models, can better deal with a comprehensive study of amyloid aggregation. In addition to the monomer aggregation and conformational transition hypothesis, we reported new emerging theories regarding the self-aggregation of α-syn, such as the alpha-helix rich tetramer hypothesis, whose destabilization induce monomer aggregation; and the liquid-liquid phase separation hypothesis, which considers a phase separation of α-syn into liquid droplets as a primary event towards the evolution to aggregates. The final aim of this review is to show how multimodal methodologies provide a complete portrait of α-syn oligomerization and can be successfully extended to other protein aggregation diseases.     

Oat Extract Avenanthramide-C Reverses Hippocampal Long-Term Potentiation Decline in Tg2576 Mice

Memory deterioration in Alzheimer’s disease (AD) is thought to be underpinned by aberrant amyloid β (Aβ) accumulation, which contributes to synaptic plasticity impairment. Avenanthramide-C (Avn-C), a polyphenol compound found predominantly in oats, has a range of biological properties. Herein, we performed methanolic extraction of the Avns-rich fraction (Fr. 2) from germinated oats using column chromatography, and examined the effects of Avn-C on synaptic correlates of memory in a mouse model of AD. Avn-C was identified in Fr. 2 based on ¹H-NMR analysis. Electrophysiological recordings were performed to examine the effects of Avn-C on the hippocampal long-term potentiation (LTP) in a Tg2576 mouse model of AD. Avn-C from germinated oats restored impaired LTP in Tg2576 mouse hippocampal slices. Furthermore, Avn-C-facilitated LTP was associated with changes in the protein levels of phospho-glycogen synthase kinase-3β (p-GSK3β-S9) and cleaved caspase 3, which are involved in Aβ-induced synaptic impairment. Our findings suggest that the Avn-C extract from germinated oats may be beneficial for AD-related synaptic plasticity impairment and memory decline.     

Natural Alkaloid Compounds as Inhibitors for Alpha-Synuclein Seeded Fibril Formation and Toxicity

The accumulation and aggregation of α-synuclein (α-syn) is the main pathologic event in Parkinson’s disease (PD), dementia with Lewy bodies, and multiple system atrophy. α-Syn-seeded fibril formation and its induced toxicity occupy a major role in PD pathogenesis. Thus, assessing compounds that inhibit this seeding process is considered a key towards the therapeutics of synucleinopathies. Using biophysical and biochemical techniques and seeding-dependent cell viability assays, we screened a total of nine natural compounds of alkaloid origin extracted from Chinese medicinal herbs. Of these compounds, synephrine, trigonelline, cytisine, harmine, koumine, peimisine, and hupehenine exhibited in vitro inhibition of α-syn-seeded fibril formation. Furthermore, using cell viability assays, six of these compounds inhibited α-syn-seeding-dependent toxicity. These six potent inhibitors of amyloid fibril formation and toxicity caused by the seeding process represent a promising therapeutic strategy for the treatment of PD and other synucleinopathies.     

Amyloidosis in Alzheimer’s Disease: Pathogeny,Etiology, and Related Therapeutic Directions

The amyloid hypothesis of Alzheimer’s disease has long been the predominant theory, suggesting that Alzheimer’s disease is caused by the accumulation of amyloid beta protein (Aβ) in the brain, leading to neuronal toxicity in the central nervous system (CNS). Because of breakthroughs in molecular medicine, the amyloid pathway is thought to be central to the pathophysiology of Alzheimer’s disease (AD). Currently, it is believed that altered biochemistry of the Aβ cycle remains a central biological feature of AD and is a promising target for treatment. This review provides an overview of the process of amyloid formation, explaining the transition from amyloid precursor protein to amyloid beta protein. Moreover, we also reveal the relationship between autophagy, cerebral blood flow, ACHE, expression of LRP1, and amyloidosis. In addition, we discuss the detailed pathogenesis of amyloidosis, including oxidative damage, tau protein, NFTs, and neuronal damage. Finally, we list some ways to treat AD in terms of decreasing the accumulation of Aβ in the brain.     

Clinical Relevance of [18F]Florbetaben and [18F]FDG PET/CT Imaging on the Management of Patients with Dementia

PET of β-Amyloid plaques (Aβ) using [¹⁸F]florbetaben ([¹⁸F]FBB) and [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) increasingly aid clinicians in early diagnosis of dementia, including Alzheimer’s disease (AD), frontotemporal disease, dementia with Lewy bodies, and vascular dementia. The aim of this retrospective analysis was to evaluate clinical relevance of [¹⁸F]FBB, [¹⁸F]FDG PET and complimentary CSF measurements in patients with suspected dementia. In this study, 40 patients with clinically suspected or history of dementia underwent (1) measurement of Aβ peptides, total tau, and p-tau protein levels in the cerebrospinal fluid (CSF) compared with healthy controls (HC); (2) clinical and neuropsychological assessment, which included Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological assessment battery (CERAD-NAB); (3) [¹⁸F]FBB and [¹⁸F]FDG PET imaging within an average of 3 weeks. The subjects were within 15 days stratified using PET, CSF measurements as HC, mild cognitive impaired (MCI) and dementia including Alzheimer´s disease. The predictive dementia-related cognitive decline values were supporting the measurements. PET images were evaluated visually and quantitatively using standard uptake value ratios (SUVR). Twenty-one (52.5%) subjects were amyloid-positive (Aβ+), with a median neocortical SUVR of 1.80 for AD versus 1.20 relative to the respective 19 (47.5 %) amyloid-negative (Aβ-) subjects. Moreover, the [¹⁸F]FDG and [¹⁸F]FBB confirmed within a sub-group of 10 patients a good complimentary role by correlation between amyloid pathology and brain glucose metabolism in 8 out of 10 subjects. The results suggest the clinical relevance for [¹⁸F]FBB combined with [¹⁸F]FDG PET retention and CFS measurements serving the management of our patients with dementia. Therefore, [¹⁸F]FBB combined with [¹⁸F]FDG PET is a helpful tool for differential diagnosis, and supports the patients’ management as well as treatment.     

β-酪蛋白淀粉样纤维沉淀的形成及影响因素

利用硫磺素T(ThT)荧光分析法和透射电子显微镜检测β-酪蛋白形成淀粉样纤维沉淀(Fibril)的动力学过程, 研究了磷脂和硫酸肝素对其Fibril形成的影响. 实验结果表明, β-酪蛋白在65 ℃下, pH值为5.4~9.0的范围内, 加热252 h以上, 并未形成Fibril, 说明β-酪蛋白是一种很好的分子伴侣, 在高温、 弱酸和弱碱条件下均不形成淀粉样纤维沉淀. 甘油磷酸胆碱D6PC和D9PC可以显著地促进β-酪蛋白的Fibril的形成, 说明一定条件下蛋白质可能与细胞膜之间存在相互作用而导致其二级构象的转变. 硫酸肝素对β-酪蛋白形成Fibril具有促进作用, 在炎症组织中, 硫酸肝素表达量的增加有可能促进β-酪蛋白形成Fibril, 说明乳腺炎与乳腺中的Corpora Amylacea的形成存在一定的联系.     

Potential Anti-Alzheimer Agents from Guanidinyl Tryptophan Derivatives with Activities of Membrane Adhesion and Conformational Transition Inhibitions

Guanidinyl tryptophan derivatives TGN1, TGN2, TGN3, and TGN4 were synthesized, and these compounds were shown to possess in vitro inhibitory activity for amyloid aggregation in a previous study. Nevertheless, the influence of the TGN series of compounds on the binding and permeation behaviors of an Aβ monomer to the cell membranes was not elucidated. In this study, we investigated the effect of compounds in the TGN series on the behavior of an Aβ monomer regarding its toxicity toward the bilayer lipid membrane using molecular dynamics (MD) simulation. MD simulations suggest that TGN4 is a potential agent that can interfere with the movement of the Aβ monomer into the membrane. The MM-GBSA result demonstrated that TGN4 exhibits the highest affinity to the Aβ_1–42 monomer but has the lowest affinity to the bilayer. Moreover, TGN4 also contributes to a decrease in the binding affinity between the Aβ_1–42 monomer and the POPC membrane. Regarding the results of the binding mode and conformational analyses, a high number of amino-acid residues were shown to provide the binding interactions between TGN4 and the Aβ_1–42 monomer. TGN4 also reduces the conformational transition of the Aβ_1–42 monomer by means of interacting with the monomer. The present study presents molecular-level insights into how the TGN series of compounds affect the membrane adsorption and the conformational transition of the Aβ_1–42 monomer, which could be valuable for the further development of new anti-Alzheimer agents.     

Hybrid Bis-Histidine Phenanthroline-Based Ligands to Lessen Aβ-Bound Cu ROS Production: An Illustration of Cu(I) Significance

We here report the synthesis of three new hybrid ligands built around the phenanthroline scaffold and encompassing two histidine-like moieties: phenHH, phenHGH and H’phenH’, where H correspond to histidine and H’ to histamine. These ligands were designed to capture Cu(I/II) from the amyloid-β peptide and to prevent the formation of reactive oxygen species produced by amyloid-β bound copper in presence of physiological reductant (e.g., ascorbate) and dioxygen. The amyloid-β peptide is a well-known key player in Alzheimer’s disease, a debilitating and devasting neurological disorder the mankind has to fight against. The Cu-Aβ complex does participate in the oxidative stress observed in the disease, due to the redox ability of the Cu(I/II) ions. The complete characterization of the copper complexes made with phenHH, phenHGH and H’phenH’ is reported, along with the ability of ligands to remove Cu from Aβ, and to prevent the formation of reactive oxygen species catalyzed by Cu and Cu-Aβ, including in presence of zinc, the second metal ions important in the etiology of Alzheimer’s disease. The importance of the reduced state of copper, Cu(I), in the prevention and arrest of ROS is mechanistically described with the help of cyclic voltammetry experiments.     

Amyloid-β oligomers regulate the properties of human neural stem cells through GSK-3β signaling

Alzheimer''s disease (AD) is the most common cause of age-related dementia. The neuropathological hallmarks of AD include extracellular deposition of amyloid-β peptides and neurofibrillary tangles that lead to intracellular hyperphosphorylated tau in the brain. Soluble amyloid-β oligomers are the primary pathogenic factor leading to cognitive impairment in AD. Neural stem cells (NSCs) are able to self-renew and give rise to multiple neural cell lineages in both developing and adult central nervous systems. To explore the relationship between AD-related pathology and the behaviors of NSCs that enable neuroregeneration, a number of studies have used animal and in vitro models to investigate the role of amyloid-β on NSCs derived from various brain regions at different developmental stages. However, the Aβ effects on NSCs remain poorly understood because of conflicting results. To investigate the effects of amyloid-β oligomers on human NSCs, we established amyloid precursor protein Swedish mutant-expressing cells and identified cell-derived amyloid-β oligomers in the culture media. Human NSCs were isolated from an aborted fetal telencephalon at 13 weeks of gestation and expanded in culture as neurospheres. Human NSCs exposure to cell-derived amyloid-β oligomers decreased dividing potential resulting from senescence through telomere attrition, impaired neurogenesis and promoted gliogenesis, and attenuated mobility. These amyloid-β oligomers modulated the proliferation, differentiation and migration patterns of human NSCs via a glycogen synthase kinase-3β-mediated signaling pathway. These findings contribute to the development of human NSC-based therapy for AD by elucidating the effects of Aβ oligomers on human NSCs.     

Effects of Curcumin and Ferulic Acid on the Folding of Amyloid-β Peptide

The polyphenols curcumin (CU) and ferulic acid (FA) are able to inhibit the aggregation of amyloid-β (Aβ) peptide with different strengths. CU is a strong inhibitor while FA is a weaker one. In the present study, we examine the effects of CU and FA on the folding process of an Aβ monomer by 1 µs molecular dynamics (MD) simulations. We found that both inhibitors increase the helical propensity and decrease the non-helical propensity of Aβ peptide. They prevent the formation of a dense bulk core and shorten the average lifetime of intramolecular hydrogen bonds in Aβ. CU makes more and longer-lived hydrogen bonds, hydrophobic, π–π, and cation–π interactions with Aβ peptide than FA does, which is in a good agreement with the observed stronger inhibitory activity of CU on Aβ aggregation.