The spatiotemporal dynamics of triglyceride (TG) storage in unilocular adipocytes are not well understood. Here we applied ex vivo technology to study trafficking and metabolism of fluorescent fatty acids in adipose tissue explants. Live imaging revealed mul? tiple cytoplasmic nodules surrounding the large central lipid droplet (cLD) of unilocular adi? pocytes. Each cytoplasmic nodule harbors a series of closely associated cellular organelles, including micro-lipid droplets (mLDs), mitochondria, and the endoplasmic reticulum. Exoge? nously added free fatty acids are rapidly adsorbed by mLDs and concurrently get esterified to TG. This process is greatly accelerated by insulin. mLDs transfer their content to the cLD, serving as intermediates that mediate packaging of newly synthesized TG in the large inte? rior of a unilocular adipocyte. This study reveals novel cell biological features that may con? tribute to the mechanism of adipocyte hypertrophy.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology