Mathematical analysis of hepatic high density lipoprotein transport based on quantitative imaging data

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Item Type:	Article
Title:	Mathematical analysis of hepatic high density lipoprotein transport based on quantitative imaging data
Creators Name:	Wuestner, D.
Abstract:	Hepatocytes internalize high density lipoprotein (HDL) at the basolateral membrane. Most HDL is recycled while some is shuttled to the canalicular membrane by transcytosis. Here, transport of HDL was analyzed by mathematical modeling based on measurements in polarized hepatic HepG2 cells. Recycling of HDL from basolateral sorting endosomes was modeled by applying the rapid equilibrium approach. Analytical expressions were derived, which describe in one model the transport of HDL to the subapical compartment/apical recycling compartment, the biliary canaliculus (BC), and to late endosomes and lysosomes (LE/LYS). Apical endocytosis of HDL predicted by the model was confirmed for rhodamine-dextran and fluorescent asialoorosomucoid, markers for LE/LYS in living HepG2 cells. Budding of endocytic vesicles from the BC was directly observed by time lapse imaging of a fluorescent lipid probe. Based on fitted kinetic parameters and their covariance matrix a Monte Carlo simulation of HDL transport in hepatocytes was performed. The model was used to quantitatively assess release of HDL-associated free cholesterol by scavenger receptor BI. It is shown that only 6% of HDL-associated sterol reaches the BC as a constituent of the HDL particles, whereas the remaining sterol is rapidly released from HDL and shuttled to the BC by non-vesicular transport.
Keywords:	Bile Canaliculi, Biological Models, Biological Transport, Cell Polarity, Computer-Assisted Image Processing, Endocytosis, Endosomes, HDL Lipoproteins, Kinetics, Liver, Lysosomes, Monte Carlo Method, Sterols, Theoretical Models, Tumor Cell Line
Source:	Journal of Biological Chemistry
ISSN:	0021-9258
Publisher:	American Society for Biochemistry and Molecular Biology
Volume:	280
Number:	8
Page Range:	6766-6779
Date:	1 January 2005
Official Publication:	https://doi.org/10.1074/jbc.M413238200
PubMed:	View item in PubMed

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