Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the formation of toxic amyloid-β (Aβ) oligomers and plaques. Considering that Aβ misfolding and aggregation precedes the progressive development of cognitive impairment in AD, investigating a therapeutic means by clearance of pre-existing Aβ aggregates shows promise as a viable disease-modifying treatment. Here, we report that a small molecule, necrostatin-1 (Nec-1), reduces Aβ aggregates back to non-toxic monomers in vitro and in vivo. Intravenous administration of Nec-1 reduced the levels of Aβ plaques in the brains of aged APP/PS1 double transgenic mice. In addition, Nec-1 exhibited therapeutic effects against Aβ aggregates by inhibiting Aβ-induced brain cell death in neuronal and microglial cell lines. Nec-1 also showed anti-apoptotic and anti-necroptotic effects in the cortex of aged APP/PS1 mice by reducing levels of phosphorylated-RIPK3 and Bax and increasing the levels of Bcl-2. According to our data in vitro and in silico, the methyl group of the amine in the 2-thioxo-4-imidazolidinone is the key moiety of Nec-1 that directs its activity against aggregated Aβ. Given that the accumulation of Aβ aggregates is an important hallmark of AD, our studies provide strong evidence that Nec-1 may serve a key role in the development of AD treatment.

As amyloid-β (Aβ) peptide is considered a biomarker and pathological culprit of Alzheimer's disease, Aβtargeting compounds have been investigated for diagnostics development and drug discovery of the disorder. Unlike amyloid plaque targeting agents, such as clinically available amyloid radiotracers intercalating into the β-sheet structures of the aggregates, monomer and oligomer targeting chemicals are difficult to develop, as the transient and polymorphic nature of these peptides impedes their structural understanding. Here, we report a mapping approach to explore targeting residues of Aβ-imaging probes and Aβ-regulating drug candidates by utilizing a set of fragmented Aβ hexamers immobilized on a 96-well microplate in combination with fluorescent full-length Aβ for on-plate aggregation. To evaluate the mapping potential of the peptide plate, we tested previously reported fluorescent imaging agents (CRANAD-28, bis-ANS), aggregation inhibitors (curcumin, scyllo-inositol), and aggregate dissociators (necrostatin-1, sunitinib) targeting Aβ. Our approach enabled mechanistic understanding of compounds targeting nonfibrillar Aβ on an interacting sequence level.

Alzheimer's disease (AD), the most common cause of dementia, is a complex condition characterized by multiple pathophysiological mechanisms including amyloid‐β (Aβ) plaque accumulation and neuroinflammation in the brain. The current immunotherapy approaches, such as anti‐Aβ monoclonal antibody (mAb) therapy, Aβ vaccines, and adoptive regulatory T (Treg) cell transfer, target a single pathophysiological mechanism, which may lead to unsatisfactory therapeutic efficacy. Furthermore, Aβ vaccines often induce T helper 1 (Th1) cell‐mediated inflammatory responses. Here, a nanovaccine composed of lipid nanoparticles loaded with Aβ peptides and rapamycin is developed, which targets multiple pathophysiological mechanisms, exhibits the combined effects of anti‐Aβ antibody therapy and adoptive Aβ‐specific Treg cell transfer, and can overcome the limitations of current immunotherapy approaches for AD. The Nanovaccine effectively delivers rapamycin and Aβ peptides to dendritic cells, produces both anti‐Aβ antibodies and Aβ‐specific Treg cells, removes Aβ plaques in the brain, alleviates neuroinflammation, prevents Th1 cell‐mediated excessive immune responses, and inhibits cognitive impairment in mice. The nanovaccine shows higher efficacy in cognitive recovery than an Aβ vaccine. Unlike anti‐Aβ mAb therapy and adoptive Treg cell transfer, both of which require complicated and costly manufacturing processes, the nanovaccine is easy‐to‐prepare and cost‐effective. The nanovaccines can represent a novel treatment option for AD.

Background Aggregated amyloid-β (Aβ) is considered a pathogenic initiator of Alzheimer’s disease (AD), in strong association with tau hyperphosphorylation, neuroinflammation, synaptic dysfunction, and cognitive decline. As the removal of amyloid burden from AD patient brains by antibodies has shown therapeutic potential, the development of small molecule drugs inducing chemical dissociation and clearance of Aβ is compelling as a therapeutic strategy. In this study, we synthesized and screened aryloxypropanolamine derivatives and identified 1-(3-(2,4-di-tert-pentylphenoxy)-2-hydroxypropyl)pyrrolidin-1-ium chloride, YIAD002, as a strong dissociator of Aβ aggregates. Methods The dissociative activity of aryloxypropanolamine derivatives against Aβ aggregates were evaluated through in vitro assays. Immunohistochemical staining, immunoblot assays, and the Morris water maze were used to assess the anti-Alzheimer potential in YIAD002-treated 5XFAD and transgenic APP/PS1 mice. Target-ligand interaction mechanism was characterized via a combination of peptide mapping, fluorescence dissociation assays, and constrained docking simulations. Results Among 11 aryloxypropanolamine derivatives, YIAD002 exerted strongest dissociative activity against β-sheet-rich Aβ aggregates. Upon oral administration, YIAD002 substantially reduced amyloid burden and accordingly, improved cognitive performance in the Morris water maze and attenuated major pathological hallmarks of AD including tauopathy, neuroinflammation, and synaptic protein loss. Mechanism studies suggest that YIAD002 interferes with intermolecular β-sheet fibrillation by directly interacting with KLVFFA and IGLMVG domains of Aβ. In addition, YIAD002 was found to possess dissociative activity against aggregates of pyroglutamate-modified Aβ and tau. Conclusions Collectively, our results evince the potential of chemical-driven dissociation of Aβ aggregates by aryloxypropanolamines as a therapeutic modality of the amyloid clearance approach.

Cerebral amyloid-β (Aβ) deposition is a representative hallmark of Alzheimer's disease (AD). Development of Aβclearing small molecules could be an advantageous therapeutic strategy for Aβ clearance considering the advantages in terms of side effects, cost-effectiveness, stability, and oral bioavailability. Here, we report an Aβ-dissociating small molecule, YIAD-0121, a derivative of 4-acyl-3,4-dihydropyrrolo[1,2-a]pyrazine. Through a series of anti-Aβ screening assays, YIAD-0121 was identified to inhibit Aβ aggregation and dissociate preformed Aβ fibrils in vitro. Furthermore, the administration of YIAD-0121 in 5XFAD transgenic AD mice inhibited the increase of cerebral Aβ aggregation and progression of hippocampus-dependent cognitive decline, with ameliorated neuroinflammation.