Enterocyte Lipid Droplet and Mitochondrial Interaction in Zebrafish (Danio rerio) Larvae During High Fat Diet Absorption

Abstract

Diets associated with the development of dyslipidemias are typically high in triglycerides and cholesterol. These lipids are readily absorbed by intestinal enterocytes and there processed and packaged for delivery to the whole organism. Much remains unknown about the energetic mechanisms regulating dietary lipid processing within intestinal enterocytes. The purpose of this study is to better elucidate the dynamic interaction of lipid droplets and mitochondria during lipid absorption in the zebrafish model. Previous work in our lab has shown that larvae fed a high fat diet undergo lipid droplet biogenesis. We hypothesized that an increase in the size of the lipid droplets will cause mitochondria biogenesis or fusion while increasing apposition with lipid droplets. To test this prediction, zebrafish 6 day post fertilization larvae were fed a high fat diet of chicken egg yolk for one hour, rinsed, and fixed for TEM to create a 10 hour time course. Larvae were then sectioned, and imaged via TEM for each hour post feeding. Numbers of mitochondria decreased (43±7, 0 hours vs. 30±7, 3 hours) early upon feeding while area the total number of mitochondria increased (21±14 μm vs. 28±9 μm). Apposition between lipid droplets and mitochondria increased (from 0 vs. 5±1) during the same time frame and decrease by hour 10. Our results indicate that mitochondrial/lipid droplet apposition events correlate with lipid droplet processing or maturation. Future studies will attempt to further validate the zebrafish enterocyte model by comparison of other vertebrates. This work was supported by WV‐INBRE Grant# 2P20GM1.343_14 P1500699 to the West Virginia IDeA Network for Biomedical Research Excellence, NIH Grant P20GM103434Support or Funding InformationThis work was supported by WV‐INBRE Grant# 2P20GM1.343_14 P1500699 to the West Virginia IDeA Network for Biomedical Research Excellence, NIH Grant P20GM103434This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.