Apolipoprotein A5 internalized by human adipocytes modulates cellular triglyceride content
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Xiao-Yan Zheng
,
Bi-Lian Yu
Abstract
Apolipoprotein A5 (apoA5), an important determinant of plasma triglyceride (TG) levels, has been recently reported to modulate TG metabolism in hepatocytes. In this study, we investigated whether apoA5 can be internalized by adipocytes and regulate cellular TG storage. Human preadipocytes, derived from subcutaneous adipose tissue of patients undergoing abdominal surgery, were differentiated into mature adipocytes. Pulse-chase experiments revealed that apoA5 was internalized into human adipocytes, and ∼70% of the apoA5 internalized during the pulse remained intracellular within a 24-h chase, while 30% was degraded. Preincubation with heparin and the receptor-associated protein, both of which prevented the apoA5 interaction with members of the low-density lipoprotein receptor gene family, markedly reduced the uptake of apoA5 by 61% and 52%, respectively, which were subsequently confirmed by Western blot analysis. Using confocal microscopy, we demonstrated that labeled apoA5 surrounded lipid droplets in human adipocytes and colocalized with the known lipid droplet protein perilipin. Importantly, treatment of adipocytes with apoA5 significantly decreased cellular TG storage. In conclusion, apoA5 can be internalized by human adipocytes and may act as a novel regulator to control TG storage in human adipocytes.
©2012 by Walter de Gruyter Berlin Boston
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Artikel in diesem Heft
- Genes and Nucleic Acids
- The effect of cancer procoagulant on expression of metastatic and angiogenic markers in breast cancer and embryonic stem cell lines
- Characterization of RNA damage under oxidative stress in Escherichia coli
- Membranes, Lipids, Glycobiology
- Uncommon membrane distribution of Shiga toxin glycosphingolipid receptors in toxin-sensitive human glomerular microvascular endothelial cells
- Cell Biology and Signaling
- Nucleocytoplasmic shuttling of human inositol phosphate multikinase is influenced by CK2 phosphorylation
- Apolipoprotein A5 internalized by human adipocytes modulates cellular triglyceride content
- Mammalian carboxylesterase (CES) releases GPI-anchored proteins from the cell surface upon lipid raft fluidization
- Proteolysis
- Biochemical characterization and structural modeling of human cathepsin E variant 2 in comparison to the wild-type protein
- Novel Techniques
- A fluorescence correlation spectroscopy-based enzyme assay for human Dicer
- Development of a host blood meal database: de novo sequencing of hemoglobin from nine small mammals using mass spectrometry
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