bims-amyloi 2026-08-16 papers

bims-amyloi

Biomed News

on Amyloid

Issue of 2026–08–16
thirteen papers selected by
Alexander Röntgen, University of Cambridge

Liquid-liquid phase-separated tau colocalizes with and stabilizes Aβ oligomers.
Structural basis of α-synuclein and DJ-1 complex.
Multiple system atrophy-derived α-synuclein fibrils are more potent and display oligodendrocyte cell tropism compared to Parkinson's disease-derived fibrils.
Dual roles of condensates in protein misfolding and aggregation.
α-Synuclein burden amplification in Parkinson's disease: a unified genetic, molecular, and cellular framework.
Lipid-conjugated Ru(iii) complexes as inhibitors of pathological peptide aggregation in neurodegenerative disorders.
Research progress on the α-synuclein-lysosome axis in Parkinson's disease: molecular mechanisms of protein aggregation, autophagy dysfunction, and therapeutic targeting.
Amplification of seeding-competent tau aggregates by PMCA in human and experimental tauopathies.
Tau dysfunction in alzheimer's disease: molecular and cellular mechanisms, genetic modulation, and therapeutic perspectives.
Extracellular Aβ42 Oligomers Induce ROCK2 Hyperactivation Through Dual Mediation by RhoA and GzmB: Significance of Moderate ROCK2 Activity in Neural Cells.
Chemical probes for Alzheimer's disease targets.
A Novel Plate Reader-Based Protocol for Measurement of DNAJB6 Dimerization Activity.
A new method for the production of recombinant human Aβ(1-42) peptide.

Commun Chem. 2026 Aug 10. pii: 273. [Epub ahead of print]9(1):

Liquid-liquid phase-separated tau colocalizes with and stabilizes Aβ oligomers.

Tina Jacob, Marie P Schützmann, Laurin Gerhards, Laura Hruby, Gabriel Leprivier, Gültekin Tamgüney, Wolfgang Hoyer.

Protein aggregation is a hallmark of neurodegenerative diseases, where misfolded proteins accumulate into insoluble deposits. Emerging studies indicate that liquid-liquid phase separation (LLPS) may serve as a transient stage in the transition from monomers to amyloid fibrils for several proteins implicated in neurological disorders. In this study, we investigated the interplay between tau and off-pathway oligomers of amyloid-beta (Aβ), the two key proteins in Alzheimer's disease (AD). Our findings demonstrate that tau condensates act as reservoirs for Aβ oligomers under LLPS conditions. Inside the tau condensates, Aβ oligomers reduced tau dynamics and formed discrete puncta, indicating a conducive environment for Aβ oligomer clustering. In contrast, in the absence of LLPS conditions, tau and Aβ oligomers formed solid-like co-aggregates with distinct morphologies. Tau significantly affected the kinetics of Aβ assembly, stabilizing off-pathway oligomers and inhibiting their replacement by amyloid fibrils. Our results highlight interactions between higher-order assemblies of tau and Aβ that may contribute to AD pathology.

DOI: https://doi.org/10.1038/s42004-026-02165-6
Int J Biol Macromol. 2026 Aug 12. pii: S0141-8130(26)03967-X. [Epub ahead of print] 154021

Structural basis of α-synuclein and DJ-1 complex.

Hyeon Jin Kim, Da Hye Kim, Chang Woo Han, Mi Suk Jeong, Se Bok Jang.

  The structure of α-synuclein is predominantly α-helical when bound to cellular membranes. However, under pathological or destabilizing conditions, this α-helical structure transitions into β-sheet-rich conformations, promoting protein aggregation and formation of Lewy bodies (LBs) in neurodegenerative disorders such as Parkinson's disease dementia (PDD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and Alzheimer's disease (AD). DJ-1 is a multifunctional brain protein acting as a chaperone or protease under oxidative stress and associating with abnormal protein aggregates. Although previous studies suggested DJ-1 inhibits α-synuclein aggregation, the structural basis remained elusive. Here, we elucidate the direct interaction between α-synuclein and DJ-1 using size-exclusion chromatography (SEC), fluorescence spectroscopy, and multi-angle light scattering (MALS), and determined their crystal structure by X-ray diffraction. The interaction interface was mapped to residues Q24, E28, A29, and N65 of α-synuclein and K148, N173, and Q180 of DJ-1, with Q180 forming strong hydrogen bonds (2.60-2.97 Å) with α-synuclein. Transmission electron microscopy (TEM) demonstrated DJ-1 suppresses α-synuclein fibril formation. Based on the structure, we designed a DJ-1-derived peptide (173-180) that significantly inhibited α-synuclein aggregation in TEM and ELISA assays, suggesting its potential as a therapeutic candidate for α-synucleinopathies.

Keywords:  Complex; DJ-1; X-ray crystallography; α-Synuclein

DOI:  https://doi.org/10.1016/j.ijbiomac.2026.154021
Neurobiol Dis. 2026 Aug 14. pii: S0969-9961(26)00320-7. [Epub ahead of print] 107575

Multiple system atrophy-derived α-synuclein fibrils are more potent and display oligodendrocyte cell tropism compared to Parkinson's disease-derived fibrils.

Anne-Line Strange Laursen, Katarina Willén, Alexis Fenyi, Christiane Volbracht, Louise Torp Dalgaard, Susana Aznar, Ronald Melki, Karina Fog, Florence Sotty.

  Multiple System Atrophy (MSA) and Parkinson's Disease (PD) are neurodegenerative diseases characterized by abundant α-synuclein (αSyn) aggregation in the brain. Compared to PD patients, MSA patients have more widespread neurodegeneration and a more aggressive disease course. PD-related αSyn pathology is primarily neuronal, whereas MSA brains characteristically display oligodendroglial inclusions. The strain hypothesis poses that polymorphisms of the αSyn aggregates, so-called strains, may explain disease heterogeneity. The present study investigates the differential properties of αSyn fibrils derived from MSA and PD patients' brains using the protein misfolding cyclic amplification (PMCA) method in cultured neurons and in vivo. MSA- and PD-derived αSyn species were administered to primary murine neuronal cell cultures or injected intrastriatally into wildtype mice, along with de novo generated αSyn fibrils of the ribbon and fibril types. The potency to induce phosphorylated αSyn (pSyn) pathology, microglial reactivity, and the extent of oligodendroglial pSyn pathology were compared among the different seeding materials using immunohistochemical and immunofluorescent approaches. In summary, the various seeding materials induced pSyn pathology of distinguishable potency and morphology. PMCA-derived material from MSA brains and the fibril polymorph induced more pSyn pathology in both neuronal cultures and in mice compared to PMCA-derived material from PD brains and the ribbon polymorph. Interestingly, amplified material from MSA brains induced significantly more oligodendroglial pSyn aggregates than amplified material from PD brains. Additionally, mice injected with the fibril polymorph, showed mild changes in microglial reactivity. Our findings suggest specific properties of the MSA- and PD-derived fibrils, and overall support the strain hypothesis.

Keywords:  Multiple system atrophy; Oligodendroglia; PMCA; Parkinson's disease; Strains; α-Synuclein

DOI:  https://doi.org/10.1016/j.nbd.2026.107575
Curr Opin Struct Biol. 2026 Aug 14. pii: S0959-440X(26)00137-5. [Epub ahead of print]101 103355

Dual roles of condensates in protein misfolding and aggregation.

Emre Pekbilir, Dorothee Dormann.

Protein aggregation is a hallmark in several neurodegenerative diseases, in which proteins assemble into structurally diverse misfolded states, ranging from amorphous aggregates to amyloid fibrils. Several aggregation-prone proteins can undergo phase separation to form biomolecular condensates, creating distinct chemical environments compared to the surrounding dilute phase. These environments dictate protein conformations, interaction networks, and free energy landscapes, thereby modulating aggregation pathways. Notably, condensates exert dual and context-dependent effects: they can promote aggregation by stabilizing misfolded intermediates and facilitating assembly, or they can suppress aggregation by buffering interactions and retaining proteins. Here, we summarize the current literature and describe biomolecular condensates as key regulators of protein misfolding and aggregation and highlight the importance of the local milieu in determining aggregation outcomes.

DOI: https://doi.org/10.1016/j.sbi.2026.103355
Front Neurol. 2026 ;17 1924943

α-Synuclein burden amplification in Parkinson's disease: a unified genetic, molecular, and cellular framework.

Sachiko Noda, Nobutaka Hattori.

   Introduction: Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized pathologically by the accumulation and propagation of α-synuclein (α-syn). Although α-syn aggregation is considered central to PD pathogenesis, increasing evidence suggests that α-syn abundance may be as important as its conformational state. Genetic studies have demonstrated an SNCA dosage effect, with gene duplication and triplication associated with progressively more severe familial PD phenotypes. Complementary evidence indicates that dysfunction of protein clearance pathways, particularly the autophagy-lysosome system, promotes intracellular α-syn accumulation and increases its neurotoxic potential. In this review, we propose α-syn multiplication as an integrative framework for interpreting PD pathogenesis. This concept extends beyond SNCA copy-number variation to encompass processes that increase the effective α-syn burden within neurons or across neural networks, including increased gene expression, impaired degradation, disrupted proteostasis, and pathological propagation.
Methods: We summarize α-syn structural dynamics and the concentration-dependent distribution of monomeric, oligomeric, and fibrillar species. We then review evidence from SNCA gene-dosage studies and examine the role of the autophagy-lysosome pathway in regulating α-syn homeostasis, with particular emphasis on recent experimental findings demonstrating that autophagy deficiency exacerbates α-syn accumulation and neurodegeneration in human α-syn bacterial artificial chromosome transgenic mice.
Results: Collectively, the available genetic, biochemical, and experimental evidence supports a model in which the balance between α-syn production and clearance influences disease progression alongside protein misfolding. The interaction between increased protein burden and impaired clearance capacity provides a unifying mechanism linking familial and sporadic forms of PD.
Discussion: We propose that α-syn multiplication offers an integrative framework for understanding PD pathogenesis, provides a quantitative perspective on disease heterogeneity, and highlights therapeutic opportunities aimed at reducing α-syn burden and restoring proteostatic balance.

Keywords:  Parkinson’s disease; SNCA; autophagy–α-synuclein homeostasis; neurodegeneration; protein aggregation; α-synuclein

DOI:  https://doi.org/10.3389/fneur.2026.1924943
RSC Med Chem. 2026 Jul 29.

Lipid-conjugated Ru(iii) complexes as inhibitors of pathological peptide aggregation in neurodegenerative disorders.

Claudia Riccardi, Ettore Napolitano, Chiara Platella, Andrea Conte, Simona Paladino, Domenica Musumeci, Daniela Montesarchio.

Neurodegenerative diseases (NDs), characterized by the progressive loss of neuronal homeostasis and function, represent an increasing global health burden. Their severity and profound impact on quality of life highlight the urgent need for effective and targeted therapeutic strategies. Recent studies have drawn attention to the potential of certain Ru(iii) complexes, including NAMI-A and KP1019, as promising therapeutic candidates for NDs. Originally developed as anticancer agents, these compounds have demonstrated remarkable activity in inhibiting the aggregation of model misfolded proteins, which represent a common pathological feature of various neurological disorders. Herein, searching for Ru(iii) complexes which could be effective as anti-neurodegenerative agents, we selected AziRu - a NAMI-A-like compound - and some of its lipid-conjugated derivatives, previously explored as anticancer drug candidates, and tested them for their ability to interfere with the self-aggregation of selected model peptides involved in the pathogenesis of NDs, such as Alzheimer's disease (AD), Parkinson's disease (PD) and prion diseases. Among them, the Ru(iii) complexes we named MyriPyRu and PalmiPyRu, bearing myristic and palmitic acid-based tails, respectively, emerged as promising candidates. These complexes effectively modulated and inhibited the aggregation of amyloid peptides linked to AD pathogenesis with IC50 values in the low micromolar range (ca. 5 μM for both compounds). More detailed studies on their interaction with AD peptides revealed their capacity to be coordinated by histidine residues in the N-terminal region. Biological investigations on human neuroblastoma-derived cells indicated no relevant cytotoxicity at concentrations comparable to those that caused anti-aggregation effects. Overall, these findings are highly promising, as MyriPyRu or PalmiPyRu could be the starting compounds to evolve further modified derivatives functionalized with specific targeting moieties for amyloid peptides, potentially paving the way to a new generation of Ru(iii)-based anti-amyloid agents for the treatment of Alzheimer's disease.

DOI: https://doi.org/10.1039/d6md00529b
Front Neurosci. 2026 ;20 1885103

Research progress on the α-synuclein-lysosome axis in Parkinson's disease: molecular mechanisms of protein aggregation, autophagy dysfunction, and therapeutic targeting.

Jiaojiao Fu, Chuanxi Zhu, Zhenzhen Fan.

  Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder worldwide, characterized pathologically by the loss of dopaminergic neurons in the substantia nigra and the formation of Lewy bodies, which predominantly consist of misfolded α-synuclein (α-Syn) aggregates. Recent advances have highlighted the critical role of the interplay between α-Syn and lysosomal function, termed the α-Syn-lysosome axis, as a central mechanism underlying PD pathogenesis. This review systematically summarizes the molecular mechanisms driving α-Syn aggregation and the lysosomal dysfunction contributing to impaired autophagy-lysosome pathway (ALP) activity. We further discuss emerging therapeutic strategies targeting this axis to restore lysosomal function and mitigate α-Syn toxicity. By integrating the latest findings from molecular biology, cell biology, and preclinical studies, this article aims to elucidate the complex regulatory network of the α-Syn-lysosome axis and provide a theoretical foundation for the development of novel therapeutic interventions for PD.

Keywords:  Parkinson’ s disease; autophagy; lysosome; protein aggregation; α-synuclein

DOI:  https://doi.org/10.3389/fnins.2026.1885103
Acta Neuropathol Commun. 2026 Aug 14. pii: 166. [Epub ahead of print]14(1):

Amplification of seeding-competent tau aggregates by PMCA in human and experimental tauopathies.

Florian Almela, Maxime Belondrade, Raphaelle Caillierez, Sarah Leclercq, Thomas Bouillet, Séverine Bégard, Marie Oosterlynck, Sabiha Eddarkaoui, Susana Boluda, Luc Buée, Simon Nicot, Morvane Colin, Daisy Bougard.

  Tau assemblies, associated with tauopathies, are believed to self-propagate through prion-like mechanisms in the central nervous system, driving neurodegeneration. Recently, protein seed amplification assays have emerged as highly sensitive methods for detecting trace amounts of misfolded protein assemblies across various neurodegenerative diseases. In this study, we utilized protein misfolding cyclic amplification (PMCA) to demonstrate that tau assemblies from the brains of transgenic mice or human patients with tauopathies can be efficiently amplified. Amplification was achieved using complex matrix substrates, such as brain homogenates or cell lysates expressing aggregation-prone mutant tau proteins, with heparin as a cofactor. This assay enabled the highly sensitive detection of tau assemblies, even at 1-million-fold dilutions of brain homogenate from aged and symptomatic THY-Tau30 transgenic mice (a model of tauopathy) and human cases of frontotemporal lobar degeneration (FTLD-P301L). Tau assemblies from Alzheimer's disease (AD) patients were also successfully amplified, albeit with lower sensitivity compared to other tauopathies. Critically, the PMCA-generated tau assemblies retained seeding competence, inducing further tau aggregation in reporter tau "biosensor" cells and in young THY-Tau30 mice following intracerebral injection. Together, our findings establish PMCA as an in vitro model for studying the seeded aggregation of tau assemblies, providing a powerful tool to advance research into tau aggregation mechanisms and the development of therapeutic interventions.

Keywords:  Alzheimer’s disease; FTLD; PMCA; Prion; Seed amplification; Tau

DOI:  https://doi.org/10.1186/s40478-026-02345-4
Mol Biol Rep. 2026 Aug 13. pii: 1396. [Epub ahead of print]53(1):

Tau dysfunction in alzheimer's disease: molecular and cellular mechanisms, genetic modulation, and therapeutic perspectives.

Sreenivasulu Sura, Saravanan Jagadeesan, Mohamad Aris Mohd Moklas, Siti Saleha Masrudin, Krishna Chaitanya Reddy Dandala, John Paul Judson, Nurul Huda MohdNor.

  Amyloid-beta (Aβ) plaque formation and tauopathy are two of several hallmarks of Alzheimer's disease (AD), a neurodegenerative disease. AD's widely known pathological hallmarks include extracellular amyloid-β deposition, neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein, synaptic dysfunction, neuroinflammation, and cognitive decline. These pathological hallmarks can be explained at the neurochemical level as a loss of biochemical homeostasis in the brain. Dysregulated kinase-phosphatase signalling, altered post-translational modifications, and disrupted synaptic neurochemistry eventually push tau protein towards its pathological aggregation-prone form. Among these hallmarks, recent research has found that tau pathology plays a major role in neurodegeneration and cognitive decline. Tau protein typically acts as a microtubule-stabilizing protein that helps maintain neuronal structure. In AD, pathological hyperphosphorylation, post-translational modifications, and redistribution of tau trigger its dysfunction and cytotoxicity. Pathological tau protein accumulates in neurons and undergoes a series of changes that include hyperphosphorylation, aberrant post-translational modifications, missorting, aggregation, fibrillization, and seeding as it spreads between cells. Mutations in APP, PSEN1, and PSEN2 can have downstream effects on tau pathology. Variants in APOE, BIN1, PICALM, CD2AP, and TREM2 also influence tau pathology through cellular pathways including lipid metabolism, endocytic trafficking, proteostasis, and synaptic and neuroimmune mechanisms. These findings support a model in which tau dysfunction results from the convergence of molecular aberrations and genetic susceptibility within a pathological network involving amyloid-β, neuroinflammation, and synaptic failure. This review summarizes tau molecular and cellular mechanisms of tau dysfunction in AD, genetic factors regulating tau pathology, and emerging therapeutic approaches to mitigate tau-mediated neurodegeneration.

Keywords:  Alzheimer’s disease; MAPT; Neurofibrillary tangles; Neuroinflammation; Tau pathology; Tau therapeutics

DOI:  https://doi.org/10.1007/s11033-026-12578-0
Cells. 2026 Jul 30. pii: 1379. [Epub ahead of print]15(15):

Extracellular Aβ42 Oligomers Induce ROCK2 Hyperactivation Through Dual Mediation by RhoA and GzmB: Significance of Moderate ROCK2 Activity in Neural Cells.

Changxin Zheng, Kai Wen, He Li, Tianyu Zhang, Yingjiu Zhang.

  Alzheimer's disease (AD) is characterized by neurite degeneration and neuronal death. Extracellular amyloid-β 1-42 (Aβ42) oligomers (EAO) not only disrupt the homeostasis and function of the extracellular matrix (ECM) but also damage neural cells through direct binding. Previous studies have demonstrated that EAO binding to membrane integrins reduces neuronal motility, adhesion, and neuritogenesis. To identify the key molecular switch(es) responsible for these actin cytoskeleton dysfunction-associated events, this study utilized neuronal and glial cell lines as well as AD model mice to investigate the cascade underlying EAO-induced actin cytoskeleton dysfunction. This study revealed that EAO induce the dual activation of ROCK2 through RhoA and granzyme B (GzmB) mediation, with GzmB-mediated ROCK2 activation constituting a significant component of this process. ROCK2 hyperactivation in response to EAO causes dynamic dysregulation of the actin cytoskeleton, defective neuritogenesis, and ultimately reduced cell survival, leading to disturbances in brain cell populations. However, the excessive inhibition of ROCK2 activity might cause excessive neurite outgrowth, which may disrupt intrinsic neuronal networks or normal neural transmission. Thus, the disruption of ROCK2 activity might lead to impaired neuritogenesis and disturbances in brain cell populations. The findings of this study may provide important insights into AD pathogenesis and feasible therapeutic targets.

Keywords:  Alzheimer’s disease (AD); Amyloid-β protein 1-42 (Aβ42); ROCK2; RhoA; granzyme B (GzmB); integrin

DOI:  https://doi.org/10.3390/cells15151379
Essays Biochem. 2026 Aug 13. pii: EBC20260014. [Epub ahead of print]

Chemical probes for Alzheimer's disease targets.

Sheenagh G Aiken, Tryfon Zarganes-Tzitzikas, Paul E Brennan.

  Alzheimer's disease (AD) is a complex neurodegenerative disorder involving amyloid-β deposition, tau aggregation, neuroinflammation, synaptic dysfunction, and microvascular and epigenetic changes. Although recent therapeutic developments have energised the field, effective and widely accessible disease-modifying treatments remain limited. This reflects both the biological complexity of AD and the continuing challenge of validating drug targets in the central nervous system (CNS). Chemical probes are small molecules designed to investigate the function of specific proteins in biological systems. When selected and used carefully, they provide powerful tools for testing how particular targets and pathways contribute to AD biology. High-quality chemical probes for AD targets must have high selectivity, confirmed target engagement, and CNS exposure adequate for the specific biological question, with low efflux, and biomarker evidence that the intended target is engaged in brain-relevant tissue. CNS penetration should be interpreted alongside mechanism-appropriate pharmacodynamic biomarkers, since cerebrospinal fluid measurements and modelled Kp,uu do not always directly reflect brain exposure. Chemical probes have shaped current understanding of major AD-relevant pathways, including amyloid precursor protein processing by BACE1 and γ-secretase, tau phosphorylation and aggregation, epigenetic regulation, and neuroinflammatory signalling. Several compounds initially developed as potential therapies have provided valuable mechanistic insight, even where they did not translate into clinical benefit. New modalities, including targeted protein degradation, molecular glues, and peptides, are expanding the range of AD biology that can be studied. These developments illustrate the value and limitations of chemical probes and underline the need for rigorous probe selection, validation, and experimental design in AD research.

Keywords:  Alzheimers disease; chemical probes; neurodegeneration; therapeutics

DOI:  https://doi.org/10.1042/EBC20260014
Bio Protoc. 2026 Aug 05. 16(15): e5776

A Novel Plate Reader-Based Protocol for Measurement of DNAJB6 Dimerization Activity.

Anna Gelman, Leif Kofoed Nielsen, Christian Hansen.

  Progressive neurodegeneration linked to the accumulation of misfolded proteins is a hallmark of several neurodegenerative disorders, including Parkinson's disease, Huntington's disease, and Alzheimer's disease. Dysfunction in the protein homeostasis machinery correlates with pathology. The chaperone protein DNAJB6 is expressed in neurons and oligodendrocytes and has been shown to play a key role in preventing amyloid aggregation by binding to amyloidogenic proteins and facilitating their refolding or degradation, in cooperation with other chaperones. Here, we describe a simple and feasible assay that enables high-throughput screening for DNAJB6 activity in a plate reader format. We use genetically engineered HEK293 cells that stably express DNAJB6 fused to either CFP or YFP. These cells can be plated into multi-well plates, and the fluorescence resonance energy transfer (FRET) signal can be measured for analysis of DNAJB6 dimerization, which is linked to DNAJB6 activity. The protocol can be used for drug screening and to identify compounds that increase DNAJB6 dimerization, and can serve as a starting point for finding new medicines that act through modulating DNAJB6 activity. Key features • The protocol requires a plate reader capable of FRET analysis and bandwidth adjustment for CFP/YFP separation. It was developed using a CLARIOstar plate reader. • The protocol requires access to the authors' FRET DNAJB6 cell line or equivalent cells with stable expression of CFP/YFP-DNAJB6. • The assay measures DNAJB6 dimerization and can potentially be adapted to other proteins whose functional state is linked to dimerization activity. • The protocol is useful for compound screening purposes and requires pre-existing knowledge of basic cell culture.

Keywords:  Cell-based assay; DNAJB6; Drug screening; FRET; Plate reader assay

DOI:  https://doi.org/10.21769/BioProtoc.5776
Neurochem Int. 2026 Aug 11. pii: S0197-0186(26)00129-4. [Epub ahead of print]200 106238

A new method for the production of recombinant human Aβ(1-42) peptide.

Ping Chen, Liping Guo, Xuzhen Guo, Wei Hong, Weihua Meng.

   BACKGROUND: The amyloid-β protein (Aβ) plays a central role in the pathogenesis of Alzheimer's disease (AD). Chemically synthesized Aβ(1-42) is the most widely employed resource for AD mechanistic research and drug screening. However, solid-phase synthesis introduces truncated and modified byproducts, causing batch-to-batch heterogeneity and compromised experimental reproducibility.
METHODS: Herein, we established an optimized recombinant expression system utilizing a thermal green protein (TGP) fusion tag combined with TEV protease site-specific cleavage to produce tag-free, authentic human Aβ(1-42) in Escherichia coli. We systematically performed side-by-side biophysical characterization, including secondary structural transition and amyloid aggregation kinetics, to compare purified recombinant Aβ(1-42) (RecAβ) and conventional synthetic Aβ(1-42) (SynAβ). Human iPSC-derived neurons (iNs) and primary murine microglia were further applied to evaluate and compare their neurotoxicity and microglial regulatory functions.
RESULTS: The optimized TGP-TEV platform enabled robust production of high-purity RecAβ(1-42), yielding 6-7 mg intact peptide per liter of bacterial culture. Biophysical assays demonstrated that RecAβ shares highly conserved secondary structural features with SynAβ but exhibits significantly enhanced aggregation propensity. Functional assays revealed that RecAβ- and SynAβ-derived Aβ-derived diffusible ligands (ADDLs) exert equivalent neurotoxicity in human iNs. While both fibril preparations display comparable microglial binding recognition and lysosomal clearance kinetics with subtle temporal differences, RecAβ fibrils induce more severe microglial phagolysosomal dysfunction than SynAβ fibrils.
CONCLUSION: This work establishes a robust, reproducible recombinant strategy for generating authentic human Aβ(1-42). RecAβ recapitulates core AD-relevant bioactivities of commercial SynAβ while possessing stronger aggregation potency and enhanced capacity to disrupt microglial homeostatic function. This standardized recombinant Aβ preparation provides a useful tool for the investigation of Aβ biology and screening of AD therapeutic candidates.

Keywords:  Aggregation; Fibrillogenesis; Microglial dysfunction; Neurotoxicity; Recombinant Aβ(1–42)

DOI:  https://doi.org/10.1016/j.neuint.2026.106238