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Aims: The dyslipidemia associated with type 2 diabetes is a major risk factor for the development of atherosclerosis. Trans-intestinal cholesterol excretion (TICE) has recently been shown to contribute, together with the classical hepatobiliary route, to fecal cholesterol excretion and cholesterol homeostasis. The aim of this study was to develop an in vitro cell model to investigate enterocyte-related processes of TICE.
Methods: Differentiated Caco-2/TC7 cells were grown on transwells and incubated basolaterally (blood side) with human plasma and apically (luminal side) with lipid micelles. Radioactive and fluorescent cholesterol tracers were used to investigate cholesterol uptake at the basolateral membrane, intracellular distribution and apical excretion.
Results: Our results show that cholesterol is taken up at the basolateral membrane, accumulates intracellularly as lipid droplets and undergoes a cholesterol acceptor-facilitated and progressive excretion through the apical membrane of enterocytes. The overall process is abolished at 4 °C, suggesting a biologically active phenomenon. Moreover, this trans-enterocytic retrograde cholesterol transport displays some TICE features like modulation by PCSK9 and an ABCB1 inhibitor. Finally, we highlight the involvement of microtubules in the transport of plasma cholesterol from basolateral to apical pole of enterocytes.
Conclusions: The human Caco-2/TC7 cell line appears a good in vitro model to investigate the enterocytic molecular mechanisms of TICE, which may help to identify intestinal molecular targets to enhance reverse cholesterol transport and fight against dyslipidemia.
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http://dx.doi.org/10.1007/s00592-016-0936-z | DOI Listing |
Eur J Pharmacol
September 2025
Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, P. R. China; Henan Key Laboratory of Precision Clinical Pharmacy, Zhengzhou, P. R. China. Electronic address:
Drug-induced liver injury is a major cause of acute liver failure. Crizotinib is a first-line treatment for patients with cellular-mesenchymal epithelial transition factor (c-MET), anaplastic lymphoma kinase (ALK), and ROS proto-oncogene 1 (ROS1)-positive non-small cell lung cancer. Although some patients treated with crizotinib experience hepatic adverse effects, the underlying mechanisms remain unclear.
View Article and Find Full Text PDFJ Lipid Res
September 2025
Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address:
In an interplay with parenchymal cells of metabolically active organs such as heart and adipose tissues, vascular endothelial cells are important for the regulation of nutrient uptake and organ-specific energy metabolism. Based on high expression of the scavenger receptor B1 (SR-B1) in capillary endothelial cells of white and brown adipose tissue (BAT), we proposed a functional role for this receptor in lipid handling and adaptive thermogenesis. To address this hypothesis, we generated mice with an endothelial-specific knockout of SR-B1 and performed metabolic turnover and indirect calorimetry studies in response to environmental cues such as cold exposure and high fat diet feeding.
View Article and Find Full Text PDFProper maintenance of plasma membrane (PM) cholesterol is essential for diverse processes ranging from animal development to pathogen evasion. Despite decades of study, the mechanisms governing cellular cholesterol regulation are incomplete. Using genome-wide screens we find that ACC1, the rate-limiting enzyme in fatty acid biosynthesis, regulates PM cholesterol transport.
View Article and Find Full Text PDFStomatin is a ubiquitous and highly expressed protein in erythrocytes, which associates with cholesterol-rich microdomains in the plasma membrane and is known to regulate the activity of multiple ion channels and transporters, but the structural basis of association with stomatin targets remains unknown. Here we describe high-resolution structures of multiple stomatin complexes with endogenous binding partners isolated from human erythrocyte membranes, revealing that stomatin specifically associates with two membrane proteins involved in water transport and cell volume regulation, aquaporin-1 (AQP-1) and the urea transporter, UT-B (SLC14A1). Together, our results reveal the structural basis of stomatin oligomerization, membrane association, and target recruitment, and identify a putative role for stomatin in the regulation of osmotic balance in the erythrocyte.
View Article and Find Full Text PDFJ Clin Lipidol
August 2025
ANZAC Research institute, Concord Repatriation General Hospital and University of Sydney, Sydney, NSW, Australia (Drs Kockx, Wang, and Kritharides); Department of Cardiology, Concord Repatriation General Hospital, Sydney Local Health District and University of Sydney, Sydney, NSW, Australia (Dr Krit
Background: Indigenous Australians have an increased risk of type 2 diabetes mellitus (T2DM) and premature cardiovascular disease. Subpopulations of high-density lipoprotein (HDL) have been associated with increased cardiovascular risk, but HDL composition, size, or function have not been studied in Indigenous Australians.
Methods: The study consisted of 86 non-Indigenous participants, 43 of whom had T2DM, and 75 Indigenous participants, 36 of whom had T2DM.