4'-iodo-4'-deoxydoxorubicin disrupts the fibrillar structure of transthyretin amyloid

Joana Almeida Palha, Dario Ballinari, Nadia Amboldi, Isabel Cardoso, Rui Fernandes, Vittorio Bellotti, Giampaolo Merlini, Maria João Saraiva

Research output: Contribution to journalArticlepeer-review

Abstract

Transthyretin (TTR) is a tetrameric protein synthesized mainly by the liver and the choroid plexus, from where it is secreted into the plasma and the cerebrospinal fluid, respectively. Some forms of polyneuropathy, vitreopathy, and cardiomyopathy are caused by the deposition of normal and/or mutant TTR molecules in the form of amyloid fibrils. Familial amyloidotic polyneuropathy is the most common form of TTR amyloidosis related to the V30M variant. It is still unclear the process by which soluble proteins deposit as amyloid. The treatment of amyloid-related disorders might attempt the stabilization of the soluble protein precursor to retard or inhibit its deposition as amyloid; or aim at the resorption of the deposited amyloid. The anthracycline 4'-iodo-4'-deoxydoxorubicin (I-DOX) has been shown to reduce the amyloid load in immunoglobulin light-chain amyloidosis. We investigated 1) whether I-DOX has affinity for TTR amyloid in tissues, 2) determined the I-DOX binding constants to TTR synthetic fibrils, and 3) determined the nature of the effect of I-DOX on TTR fibrils. We report that 1) I-DOX co- localizes with amyloid deposits in tissue sections of patients with familial amyloidotic polyneuropathy; 2) I-DOX strongly interacts with TTR amyloid fibrils and presents two binding sites with k(d) of 1.5 x 10-11 mol/L and 5.6 x 10-10 mol/L, respectively; and 3) I-DOX disrupts the fibrillar structure of TTR amyloid into amorphous material, as assessed by electron microscopy but does not solubillze the fibrils as confirmed by filter assays. These data support the hypothesis that I-DOX and less toxic derivatives can prove efficient in the treatment of TTR-related amyloidosis.

Original languageEnglish
Pages (from-to)1919-1925
Number of pages7
JournalAmerican Journal of Pathology
Volume156
Issue number6
Publication statusPublished - 2000

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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