TY - JOUR T1 - Structure dynamics of ApoA-I amyloidogenic variants in small HDL increase their ability to mediate cholesterol efflux JF - bioRxiv DO - 10.1101/2020.04.08.031211 SP - 2020.04.08.031211 AU - Oktawia Nilsson AU - Mikaela Lindvall AU - Laura Obici AU - Simon Ekström AU - Jens O. Lagerstedt AU - Rita Del Giudice Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/04/10/2020.04.08.031211.abstract N2 - Specific mutations in Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) are responsible for a late-onset systemic amyloidosis. Carriers do not exhibit increased cardiovascular disease risk despite reduced levels of ApoA-I/ HDL-cholesterol. To explain this paradox, we show that the HDL particle profile of L75P and L174S patients presents a higher relative abundance of the 8.4 nm vs 9.6 nm particles, and that serum from patients, as well as reconstituted 8.4 and 9.6 nm HDL particles (rHDL), possess increased capacity to catalyze cholesterol efflux from macrophages. Synchrotron radiation circular dichroism and hydrogen-deuterium exchange revealed that the variants in 8.4 nm rHDL have altered secondary structure composition and display a more flexible binding to lipids compared to their native counterpart. The reduced HDL-cholesterol levels of patients carrying ApoA-I amyloidogenic variants are thus balanced by higher proportion of small, dense HDL particles and better cholesterol efflux due to altered, region-specific protein structure dynamics. ER -