Fibrillar conformation of an apolipoprotein A-I variant involved in amyloidosis and atherosclerosis

GISONNO, ROMINA A.; CURTO, LUCRECIA M.; GADDI, GISELA M.; SCHINELLA, GUILLERMO R.; GORGOJO, JUAN P.; ROSÚ, SILVANA A.; CORTEZ, M. FERNANDA; RAMELLA, NAHUEL A.; PRIETO, EDUARDO D.; RODRIGUEZ, M. EUGENIA; FINARELLI, GABRIELA S.; TRICERRI, M. ALEJANDRA

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 1864

0304-4165

BackgroundDifferent protein conformations may be involved in the development of clinical manifestations associated with human amyloidosis. Although a fibrillar conformation is usually the signature of damage in the tissues of patients, it is not clear whether this species is per se the cause or the consequence of the disease. Hereditary amyloidosis due to variants of apolipoprotein A-I (apoA-I) with a substitution of a single amino acid is characterized by the presence of fibrillar protein within the lesions. Thus mutations result in increased protein aggregation. Here we set up to characterize the folding of a natural variant with a mutation leading to a deletion at position 107 (apoA-I Lys107?0). Patients carrying this variant show amyloidosis and severe atherosclerosis.MethodsWe oxidized this variant under controlled concentrations of hydrogen peroxide and analyzed the structure obtained after 30-day incubation by fluorescence, circular dichroism and microscopy approaches. Neutrophils activation was characterized by confocal microscopy.ResultsWe obtained a high yield of well-defined stable fibrillar structures of apoA-I Lys107?0.In an in vitro neutrophils system, we were able to detect the induction of Neutrophils Extracellular Traps (NETs) when we incubated with oxidized apoA-I variants. This effect was exacerbated by the fibrillar structure of oxidized Lys 107?0.ConclusionsWe conclude that a pro-inflammatory microenvironment could result in the formation of aggregation-prone species, which, in addition may induce a positive feed-back in the activation of an inflammatory response.General significanceThese events may explain a close association between amyloidosis due to apoA-I Lys107?0 and atherosclerosis.