Remodeling of lipid droplets during lipolysis and growth in adipocytes

Author(s): Paar M, Jüngst C, Steiner NA, Magnes C, Sinner F, et al.

Abstract

Synthesis, storage, and turnover of triacylglycerols (TAGs) in adipocytes are critical cellular processes to maintain lipid and energy homeostasis in mammals. TAGs are stored in metabolically highly dynamic lipid droplets (LDs), which are believed to undergo fragmentation and fusion under lipolytic and lipogenic conditions, respectively. Time lapse fluorescence microscopy showed that stimulation of lipolysis in 3T3-L1 adipocytes causes progressive shrinkage and almost complete degradation of all cellular LDs but without any detectable fragmentation into micro-LDs (mLDs). However, mLDs were rapidly formed after induction of lipolysis in the absence of BSA in the culture medium that acts as a fatty acid scavenger. Moreover, mLD formation was blocked by the acyl-CoA synthetase inhibitor triacsin C, implicating that mLDs are synthesized de novo in response to cellular fatty acid overload. Using label-free coherent anti-Stokes Raman scattering microscopy, we demonstrate that LDs grow by transfer of lipids from one organelle to another. Notably, this lipid transfer between closely associated LDs is not a rapid and spontaneous process but rather occurs over several h and does not appear to require physical interaction over large LD surface areas. These data indicate that LD growth is a highly regulated process leading to the heterogeneous LD size distribution within and between individual cells. Our findings suggest that lipolysis and lipogenesis occur in parallel in a cell to prevent cellular fatty acid overflow. Furthermore, we propose that formation of large LDs requires a yet uncharacterized protein machinery mediating LD interaction and lipid transfer.

Similar Articles

Triglyceride accumulation protects against fatty acid-induced lipotoxicity

Author(s): Listenberger LL, Han X, Lewis SE, Cases S, Farese RV Jr, et al.

Activation of PPARγ and δ by dietary punicic acid ameliorates intestinal inflammation in mice

Author(s): Bassaganya-Riera J, DiGuardo M, Climent M, Vives C, Carbo A, et al.

Pomegranate: a fruit that ameliorates metabolic syndrome

Author(s): Medjakovic S, Jungbauer A

Antiobesity effects of wild ginseng (Panax ginseng C

Author(s): Mollah ML, Kim GS, Moon HK, Chung SK, Cheon YP, et al.

Antiobesity effect of oil extract of ginseng

Author(s): Kim HJ, Kang HJ, Seo JY, Lee CH, Kim YS, et al.

Activating effect of momordin, extract of bitter melon (Momordica Charantia L

Author(s): Sasa M, Inoue I, Shinoda Y, Takahashi S, Seo M, et al.

Hypoglycemic effects of crude polysaccharide from Purslane

Author(s): Gong F, Li F, Zhang L, Li J, Zhang Z, et al.

Effects of Portulaca oleracea L

Author(s): El-Sayed M

Potent α-amylase inhibitory activity of Indian Ayurvedic medicinal plants

Author(s): P S, Zinjarde SS, Bhargava SY, Kumar AR

Cinnamon in glycaemic control: Systematic review and meta analysis

Author(s): Akilen R, Tsiami A, Devendra D, Robinson N

Effect of cinnamon on glucose control and lipid parameters

Author(s): Baker WL, Gutierrez-Williams G, White CM, Kluger J, Coleman CI

Cinnamon for diabetes mellitus

Author(s): Leach MJ, Kumar S

Postlipolytic insulin-dependent remodeling of micro lipid droplets in adipocytes

Author(s): Ariotti N, Murphy S, Hamilton NA, Wu L, Green K, et al.

Fat-specific protein 27 regulates storage of triacylglycerol

Author(s): Keller P, Petrie JT, De Rose P, Gerin I, Wright WS, et al.

Fat-specific protein 27, a novel lipid droplet protein that enhances triglyceride storage

Author(s): Puri V, Konda S, Ranjit S, Aouadi M, Chawla A, et al.

Pomegranate seed oil, a rich source of punicic acid, prevents diet-induced obesity and insulin resistance in mice

Author(s): Vroegrijk IO, van Diepen JA, van den Berg S, Westbroek I, Keizer H, et al.