{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,27]],"date-time":"2026-01-27T09:07:54Z","timestamp":1769504874500,"version":"3.49.0"},"reference-count":51,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,2,23]],"date-time":"2022-02-23T00:00:00Z","timestamp":1645574400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>The release of monomers from the homotetrameric protein transthyretin (TTR) is the first event of a cascade, eventually leading to sporadic or familial TTR amyloidoses. Thus, ligands able to stabilize TTR and inhibit monomer release are subject of intense scrutiny as potential treatments against these pathologies. Here, we investigated the interaction between TTR and a non-glycated derivative of the main olive polyphenol, oleuropein (OleA), known to interfere with TTR aggregation. We coupled fluorescence studies with molecular docking to investigate the OleA\/TTR interaction using wild-type TTR, a monomeric variant, and the L55P cardiotoxic mutant. We characterized a fluorescence band emitted by OleA upon formation of the OleA\/TTR complex. Exploiting this signal, we found that a poorly specific non-stoichiometric interaction occurs on the surface of the protein and a more specific stabilizing interaction takes place in the ligand binding pocket of TTR, exhibiting a KD of 3.23 \u00b1 0.32 \u00b5M, with two distinct binding sites. OleA interacts with TTR in different modes, stabilizing it and preventing its dissociation into monomers, with subsequent misfolding. This result paves the way to the possible use of OleA to prevent degenerative diseases associated with TTR misfolding.<\/jats:p>","DOI":"10.3390\/ph15030277","type":"journal-article","created":{"date-parts":[[2022,2,24]],"date-time":"2022-02-24T00:53:26Z","timestamp":1645664006000},"page":"277","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["The Transthyretin\/Oleuropein Aglycone Complex: A New Tool against TTR Amyloidosis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0643-6249","authenticated-orcid":false,"given":"Francesco","family":"Bemporad","sequence":"first","affiliation":[{"name":"Department of Experimental and Clinical Biomedical Sciences \u201cMario Serio\u201d, University of Florence, Viale Morgagni 50, 50134 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3785-0805","authenticated-orcid":false,"given":"Manuela","family":"Leri","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Biomedical Sciences \u201cMario Serio\u201d, University of Florence, Viale Morgagni 50, 50134 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6862-9409","authenticated-orcid":false,"given":"Matteo","family":"Ramazzotti","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Biomedical Sciences \u201cMario Serio\u201d, University of Florence, Viale Morgagni 50, 50134 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Massimo","family":"Stefani","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Biomedical Sciences \u201cMario Serio\u201d, University of Florence, Viale Morgagni 50, 50134 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5243-9301","authenticated-orcid":false,"given":"Monica","family":"Bucciantini","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Biomedical Sciences \u201cMario Serio\u201d, University of Florence, Viale Morgagni 50, 50134 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gi\u00e3o, T., Saavedra, J., Cotrina, E., Quintana, J., Llop, J., Arsequell, G., and Cardoso, I. (2020). Undiscovered Roles for Transthyretin: From a Transporter Protein to a New Therapeutic Target for Alzheimer\u2019s Disease. Int. J. Mol. Sci., 21.","DOI":"10.3390\/ijms21062075"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"758","DOI":"10.1107\/S0907444996003046","article-title":"Structures of human transthyretin complexed with thyroxine at 2.0 angstrom resolution and 3\u2032,5\u2032-dinitro-N-acetyl-l-thyronine at 2.2 angstrom resolution","volume":"52","author":"Wojtczak","year":"1996","journal-title":"Acta Crystallogr. D Biol. Crystallogr."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"25832","DOI":"10.1074\/jbc.M109.017657","article-title":"Amyloidogenic potential of transthyretin variants insights from structural and computational analyses","volume":"284","author":"Cendron","year":"2009","journal-title":"J. Biol. Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"13527","DOI":"10.1021\/bi00041a032","article-title":"Comparison of lethal and nonlethal transthyretin variants and their relationship to amyloid disease","volume":"34","author":"McCutchen","year":"1995","journal-title":"Biochemistry"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1625","DOI":"10.1212\/01.WNL.0000065901.18353.AB","article-title":"Oculoleptomeningeal amyloidosis in a large kindred with a new transthyretin variant Tyr69His","volume":"60","author":"Blevins","year":"2003","journal-title":"Neurology"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"160","DOI":"10.3109\/13506120308998998","article-title":"Tabulation of human transthyretin (TTR) variants, 2003","volume":"10","author":"Connors","year":"2003","journal-title":"Amyloid"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1358","DOI":"10.1212\/WNL.0b013e3181a0fe74","article-title":"Highly selective leptomeningeal amyloidosis with transthyretin variant Ala25Thr","volume":"72","author":"Hagiwara","year":"2009","journal-title":"Neurology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1152","DOI":"10.1001\/archneur.56.9.1152","article-title":"Oculoleptomeningeal amyloidosis associated with a new transthyretin variant Ser64","volume":"56","author":"Uemichi","year":"1999","journal-title":"Arch. Neurol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1042\/BJ20070689","article-title":"Comparative in vitro and ex vivo activities of selected inhibitors of transthyretin aggregation: Relevance in drug design","volume":"408","author":"Cardoso","year":"2007","journal-title":"Biochem. J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"27207","DOI":"10.1074\/jbc.M101024200","article-title":"Tetramer dissociation and monomer partial unfolding precedes protofibril formation in amyloidogenic transthyretin variants","volume":"276","author":"Quintas","year":"2001","journal-title":"J. Biol. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/S0301-4622(00)00199-X","article-title":"Comparative calorimetric study of non-amyloidogenic and amyloidogenic variants of the homotetrameric protein transthyretin","volume":"88","author":"Shnyrov","year":"2000","journal-title":"Biophys. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"11442","DOI":"10.1021\/bi011194d","article-title":"An engineered transthyretin monomer that is non amyloidogenic, unless it is partially denatured","volume":"40","author":"Jiang","year":"2001","journal-title":"Biochemistry"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1111\/j.1365-3083.1979.tb01355.x","article-title":"Senile cardiac amyloidosis: Evidence of two different amyloid substances in the ageing heart","volume":"10","author":"Westermark","year":"1979","journal-title":"Scand. J. Immunol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"618","DOI":"10.1016\/0002-9343(83)90443-6","article-title":"Frequency and distribution of senile cardiovascular amyloid. A clinicopathologic correlation","volume":"75","author":"Cornwell","year":"1983","journal-title":"Am. J. Med."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1093\/brain\/103.3.473","article-title":"Familial oculoleptomeningeal amyloidosis","volume":"103","author":"Goren","year":"1980","journal-title":"Brain"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"41667","DOI":"10.1074\/jbc.M508753200","article-title":"L55P transthyretin accelerates subunit exchange and leads to rapid formation of hybrid tetramers","volume":"280","author":"Keetch","year":"2005","journal-title":"J. Biol. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"12119","DOI":"10.1021\/bi00096a024","article-title":"Transthyretin mutation Leu-55-Pro significantly alters tetramer stability and increases amyloidogenicity","volume":"32","author":"McCutchen","year":"1993","journal-title":"Biochemistry"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"24715","DOI":"10.1074\/jbc.273.38.24715","article-title":"The crystal structure of amyloidogenic Leu55 --> Pro transthyretin variant reveals a possible pathway for transthyretin polymerization into amyloid fibrils","volume":"273","author":"Saraiva","year":"1998","journal-title":"J. Biol. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1239","DOI":"10.1517\/13543784.2014.922541","article-title":"An overview of drugs currently under investigation for the treatment of transthyretin-related hereditary amyloidosis","volume":"23","author":"Obici","year":"2014","journal-title":"Expert. Opin. Investig. Drugs"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2658","DOI":"10.1001\/jama.2013.283815","article-title":"Repurposing diflunisal for familial amyloid polyneuropathy. A randomized clinical trial","volume":"310","author":"Berk","year":"2013","journal-title":"JAMA"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2802","DOI":"10.1007\/s00415-013-7051-7","article-title":"Long-term effects of tafamidis for the treatment of transthyretin familial amyloid polyneuropathy","volume":"260","author":"Coelho","year":"2013","journal-title":"J. Neurol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1016\/j.jacc.2019.03.012","article-title":"Transthyretin stabilization by AG10 in symptomatic transthyretin amyloid cardiomyopathy","volume":"74","author":"Judge","year":"2019","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"12","DOI":"10.3949\/ccjm.84.s3.02","article-title":"Cardiac amyloidosis: An update on diagnosis and treatment","volume":"84","author":"Donnelly","year":"2017","journal-title":"Cleve Clin. J. Med."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1056\/NEJMoa1716153","article-title":"Patisiran, an RNAi therapeutic, for hereditary transthyretin amyloidosis","volume":"379","author":"Adams","year":"2018","journal-title":"New Engl. J. Med."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.jsb.2012.07.008","article-title":"Flavonoid interactions with human transthyretin: Combined structural and thermodynamic analysis","volume":"180","author":"Trivella","year":"2012","journal-title":"J. Struct. Biol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"707","DOI":"10.1016\/j.bbrc.2011.04.133","article-title":"Mechanisms of transthyretin cardiomyocyte toxicity inhibition by resveratrol analogs","volume":"410","author":"Bourgault","year":"2011","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"26623","DOI":"10.1038\/srep26623","article-title":"Curcumin: A multi-target disease-modifying agent for late-stage transthyretin amyloidosis","volume":"6","author":"Ferreira","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3569","DOI":"10.1016\/j.febslet.2009.10.062","article-title":"Binding of epigallocatechin-3-gallate to transthyretin modulates its amyloidogenicity","volume":"583","author":"Ferreira","year":"2009","journal-title":"FEBS Lett."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.jnutbio.2015.12.009","article-title":"The polyphenol Oleuropein aglycone hinders the growth of toxic transthyretin amyloid assemblies","volume":"30","author":"Leri","year":"2016","journal-title":"J. Nutr. Biochem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2424","DOI":"10.1016\/j.febslet.2011.06.030","article-title":"Natural polyphenols inhibit different steps of the process of transthyretin (TTR) amyloid fibril formationn","volume":"585","author":"Ferreira","year":"2011","journal-title":"FEBS Lett."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"8274","DOI":"10.1021\/acs.jmedchem.9b01037","article-title":"Binding of Monovalent and Bivalent Ligands by Transthyretin Causes Different Short- and Long-Distance Conformational Changes","volume":"62","author":"Corazza","year":"2019","journal-title":"J. Med. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"328","DOI":"10.3109\/07388551.2013.794413","article-title":"Cyclodextrin-based hydrogels toward improved wound dressings","volume":"34","author":"Pinho","year":"2014","journal-title":"Crit. Rev. Biotechnol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"8063","DOI":"10.1021\/bi00421a014","article-title":"Unfolding free energy changes determined by the linear extrapolation method. 1. Unfolding of phenylmethanesulfonyl alpha-chymotrypsin using different denaturants","volume":"27","author":"Santoro","year":"1988","journal-title":"Biochemistry"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1016\/j.jmb.2005.04.016","article-title":"Prediction of \"aggregation-prone\" and \"aggregation-susceptible\" regions in proteins associated with neurodegenerative diseases","volume":"350","author":"Pawar","year":"2005","journal-title":"J. Mol. Biol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1096\/fj.01-0442hyp","article-title":"A possible role for pi-stacking in the self-assembly of amyloid fibrils","volume":"16","author":"Gazit","year":"2002","journal-title":"FASEB J."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"14454","DOI":"10.1021\/bi048582a","article-title":"Inhibition of islet amyloid polypeptide fibril formation: A potential role for heteroaromatic interactions","volume":"43","author":"Porat","year":"2004","journal-title":"Biochemistry"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3219","DOI":"10.2174\/138161208786404155","article-title":"Pathogenesis of and therapeutic strategies to ameliorate the transthyretin amyloidoses","volume":"14","author":"Sekijima","year":"2008","journal-title":"Curr. Pharm. Des."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1192","DOI":"10.1016\/j.neuint.2012.08.012","article-title":"The binding of resveratrol to monomer and fibril amyloid beta","volume":"61","author":"Ge","year":"2012","journal-title":"Neurochem. Int."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"5892","DOI":"10.1074\/jbc.M404751200","article-title":"Curcumin inhibits formation of amyloid beta oligomers and fibrils, binds plaques, and reduces amyloid in vivo","volume":"280","author":"Yang","year":"2005","journal-title":"J. Biol. Chem."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"29769","DOI":"10.1074\/jbc.M115.690172","article-title":"Transthyretin Binding Heterogeneity and Anti-amyloidogenic Activity of Natural Polyphenols and Their Metabolites","volume":"290","author":"Florio","year":"2015","journal-title":"J. Biol. Chem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"592644","DOI":"10.3389\/fnmol.2020.592644","article-title":"Modulation of the Mechanisms Driving Transthyretin Amyloidosis","volume":"13","author":"Bezerra","year":"2020","journal-title":"Front Mol. Neurosci."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Ferreira, N., Saraiva, M.J., and Almeida, M.R. (2019). Uncovering the Neuroprotective Mechanisms of Curcumin on Transthyretin Amyloidosis. Int. J. Mol. Sci., 20.","DOI":"10.3390\/ijms20061287"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/j.abb.2009.02.013","article-title":"Binding and stabilization of transthyretin by curcumin","volume":"485","author":"Pullakhandam","year":"2009","journal-title":"Arch. Biochem. Biophys."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"7862","DOI":"10.1021\/acs.jmedchem.8b00817","article-title":"Enthalpy-Driven Stabilization of Transthyretin by AG10 Mimics a Naturally Occurring Genetic Variant That Protects from Transthyretin Amyloidosis","volume":"61","author":"Miller","year":"2018","journal-title":"J. Med. Chem."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1016\/j.jnutbio.2009.04.010","article-title":"Oleuropein aglycon prevents cytotoxic amyloid aggregation of human amylin","volume":"21","author":"Rigacci","year":"2010","journal-title":"J. Nutr. Biochem"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1539","DOI":"10.1073\/pnas.1317488111","article-title":"Proteolytic cleavage of Ser52Pro variant transthyretin triggers its amyloid fibrillogenesis","volume":"111","author":"Mangione","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1002\/jcc.21334","article-title":"AutoDock Vina: Improving the speed and accuracy of docking with a new scoring function, efficient optimization, and multithreading","volume":"31","author":"Trott","year":"2010","journal-title":"J. Comput. Chem."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"512","DOI":"10.1107\/S0907444906006962","article-title":"The binding of 2,4-dinitrophenol to wild-type and amyloidogenic transthyretin","volume":"62","author":"Pereira","year":"2006","journal-title":"Acta Crystallogr. D Biol. Crystallogr."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2324","DOI":"10.1021\/acs.jcim.5b00559","article-title":"ZINC 15--Ligand Discovery for Everyone","volume":"55","author":"Sterling","year":"2015","journal-title":"J. Chem. Inf. Model."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.ijpharm.2005.01.024","article-title":"Second derivative tryptophan fluorescence spectroscopy as a tool to characterize partially unfolded intermediates of proteins","volume":"294","author":"Kumar","year":"2005","journal-title":"Int. J. Pharm."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"5189","DOI":"10.1021\/jf021179v","article-title":"Probing protein-tannin interactions by isothermal titration microcalorimetry","volume":"51","author":"Frazier","year":"2003","journal-title":"J. Agric. Food Chem."}],"container-title":["Pharmaceuticals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8247\/15\/3\/277\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:26:34Z","timestamp":1760135194000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8247\/15\/3\/277"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,23]]},"references-count":51,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2022,3]]}},"alternative-id":["ph15030277"],"URL":"https:\/\/doi.org\/10.3390\/ph15030277","relation":{},"ISSN":["1424-8247"],"issn-type":[{"value":"1424-8247","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,2,23]]}}}