title: Spatiotemporal dynamics of triglyceride storage in unilocular adipocytes.
abstract: 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 multiple cytoplasmic nodules surrounding the large central lipid droplet (cLD) of unilocular adipocytes. Each cytoplasmic nodule harbors a series of closely associated cellular organelles, including micro-lipid droplets (mLDs), mitochondria, and the endoplasmic reticulum. Exogenously 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 interior of a unilocular adipocyte. This study reveals novel cell biological features that may contribute to the mechanism of adipocyte hypertrophy.
authors.affiliation: Division of Endocrinology, Diabetes, and Clinical Nutrition, Department of Medicine, Portland, OR 97239.
authors.forename: Michael
authors.initials: M
authors.lastname: Chu
authors.affiliation: Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR 97239.
authors.forename: Harini
authors.initials: H
authors.lastname: Sampath
authors.affiliation: Divisions of Diabetes, Obesity, and Metabolism and Developmental and Reproductive Science, Beaverton, OR 97006.
authors.forename: David Y
authors.initials: DY
authors.lastname: Cahana
authors.affiliation: Division of Pathobiology and Immunology, Beaverton, OR 97006.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Kahl
authors.affiliation: Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065.
authors.forename: Romel
authors.initials: R
authors.lastname: Somwar
authors.affiliation: Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006.
authors.forename: Anda
authors.initials: A
authors.lastname: Cornea
authors.affiliation: Division of Endocrinology, Diabetes, and Clinical Nutrition, Department of Medicine, Portland, OR 97239 Divisions of Diabetes, Obesity, and Metabolism and Developmental and Reproductive Science, Beaverton, OR 97006.
authors.forename: Charles T
authors.initials: CT
authors.lastname: Roberts
authors.affiliation: Divisions of Diabetes, Obesity, and Metabolism and Developmental and Reproductive Science, Beaverton, OR 97006 varlamov@ohsu.edu.
authors.forename: Oleg
authors.initials: O
authors.lastname: Varlamov
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D052436:Adipose Tissue, White / Q000166:cytology; D000818:Animals; D002478:Cells, Cultured; D066292:Lipid Droplets / Q000378:metabolism; D050356:Lipid Metabolism; D008253:Macaca mulatta; D008297:Male; D046509:Tissue Culture Techniques; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D014280:Triglycerides