{"doi":"10.1101/2025.06.13.659328","title":"Redox reactivities of membrane-bound Amyloid-β-Cu complexes and their targeting by metallothionein-3","abstract":"Abstract Alzheimer’s disease (AD) is characterized by the accumulation of amyloid-β peptide (Aβ 1-40/42 ) in the central nervous system (CNS) and its aggregation in senile amyloid plaques. Copper coordination to Aβ triggers Aβ 1-40/42 aggregation and, in the presence of biological reducing agents, it promotes the catalytic generation of reactive oxygen species (ROS) via Fenton-type and Haber-Weiss reactions. Due to its amphiphilic nature, Aβ 1-40/42 can interact with cell membranes and compromise their integrity by thinning the lipid bilayer and forming channel-like structures potentially leading to cell death. In this work, by applying biophysical and biochemical approaches, we characterized the insertion of Aβ 1-42 into an artificial lipid bilayer system mimicking cell membranes and demonstrate that the Aβ 1-42 -lipid interaction does not prevent the Cu 2+ coordination to Aβ 1-42 . We performed a comparative analysis of the redox reactivities of membrane-bound Aβ 1-42 (memAβ 1-42 -Cu 2+ ) species with soluble Aβ 1-42 -Cu 2+ establishing that membrane insertion leads to memAβ 1-42 -Cu 2+ complexes featuring an enhanced detrimental catechol oxidase activity towards the neurotransmitter dopamine. Moreover, memAβ 1-42 -Cu 2+ efficiently catalyzes Aβ di-tyrosine crosslinking and hydroxyl radical production in the presence of ascorbate. In addition, we establish that memAβ 1-42 -Cu 2+ redox reactivity catalyze lipid peroxidation in membranes containing polyunsaturated fatty acids (PUFAs), such as arachidonic acid (AA), leading to the generation of malondialdehyde (MDA) toxic end-products. This reactivity compromises the structural integrity of the lipid bilayers resulting in membrane leakage, further substantiating how important is to control aberrant Aβ 1-40/42 -Cu 2+ interactions in AD. Metallothioneins (MTs) are key metalloproteins central to neuronal and astrocytic transition metal homeostasis and buffering. These cysteine-rich proteins bind with high affinity d 10 metals (Cu + and Zn 2+ ) forming two metal thiolate clusters in their N-terminal β-domain and C-terminal α-domain. The metallothionein-3 (MT-3) isoform is central to metal homeostasis in the CNS, but it is downregulated in AD patients, possessing a neuroprotective role in AD. MT-3 can control aberrant protein-Cu 2+ interactions and the Cu-centered redox reactivities of amyloidogenic protein-Cu 2+ complexes such as α-synuclein (Parkinson’s disease), PrP (prion disease), and soluble and aggregated Aβ 1-40 (AD). In this work, we unravel that the detrimental memAβ 1-42 -Cu 2+ catechol oxidase and redox reactivities can be efficiently silenced by MT-3 via metal swap reactions, effectively scavenging and reducing Cu 2+ to Cu + in its β-domain using thiolates as electron source, forming the redox-inert species Cu + 4 Zn 2+ 4 MT-3. Consequently, MT-3 can efficiently prevent lipid peroxidation and protect membrane structural integrity. New strategies targeting membrane-bound Aβ 1-42 -Cu 2+ complexes as key players of the AD etiology could be envisioned.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":568689,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9682,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":568986,"name":"Gabriele Meloni","orcid":"0000-0003-4976-1401","position":1,"is_corresponding":false},{"id":1414824,"name":"Luciano Perez-Medina","orcid":null,"position":0,"is_corresponding":true}],"reference_count":74,"raw_metadata":null,"created_at":"2026-07-19T02:56:55.795846Z","pmid":"40667129","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}