ZFIN ID: ZDB-PUB-190113-9
Dietary cholesterol and apolipoprotein A-I are trafficked in endosomes and lysosomes in the live zebrafish intestine
Otis, J.P., Shen, M.C., Caldwell, B.A., Reyes Gaido, O.E., Farber, S.A.
Date: 2019
Source: American journal of physiology. Gastrointestinal and liver physiology   316(3): G350-G365 (Journal)
Registered Authors: Farber, Steven, Otis, Jessica P.
Keywords: Apolipoprotein A-I, Cholesterol, endosome, lysosome, zebrafish
MeSH Terms:
  • Animals
  • Apolipoprotein A-I/adverse effects*
  • Biological Transport/physiology
  • Cholesterol/metabolism
  • Cholesterol, Dietary/metabolism*
  • Endosomes/metabolism*
  • Enterocytes/metabolism
  • Intestines/physiology
  • Lipoproteins, HDL/metabolism
  • Lysosomes/metabolism*
  • Protein Transport/physiology
  • Zebrafish
PubMed: 30629468 Full text @ Am. J. Physiol. Gastrointest. Liver Physiol.
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ABSTRACT
Difficulty in imaging the vertebrate intestine in vivo has hindered our ability to model nutrient and protein trafficking from both the luminal and basolateral aspects of enterocytes. Our goal was to use live confocal imaging to increase understanding of intestinal trafficking of dietary cholesterol and apolipoprotein A-I (APOA-I), the main structural component of high-density lipoproteins (HDL). We developed a novel assay to visualize live dietary cholesterol trafficking in the zebrafish intestine by feeding TopFluor-cholesterol (TF-cholesterol), a fluorescent cholesterol analog, in a lipid-rich, chicken egg yolk feed. Quantitative microscopy of transgenic zebrafish expressing fluorescently tagged protein markers of early, recycling, and late endosomes/lysosomes provided the first evidence of cholesterol transport in the intestinal endosomal-lysosomal trafficking system. To study APOA-I dynamics, transgenic zebrafish expressing an APOA-I fluorescent fusion protein (APOA-I-mCherry) from tissue-specific promoters were created. These zebrafish demonstrated that APOA-I-mCherry derived from the intestine accumulated in the liver and vice versa. Additionally, intracellular APOA-I-mCherry localized to endosomes and lysosomes in the intestine and liver. Moreover, live imaging demonstrated that APOA-I-mCherry co-localized with dietary TF-cholesterol in enterocytes, and this co-localization increased with feeding time. This study provides a new set of tools for the study of cellular lipid biology and elucidates a key role for endosomal-lysosomal trafficking of intestinal cholesterol and APOA-I.
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