Lipid droplet

Lipid droplets, also referred to as lipid bodies, oil bodies or adiposomes,^[1] are lipid-rich cellular organelles that regulate the storage and hydrolysis of neutral lipids and are found largely in the adipose tissue.^[2] They also serve as a reservoir for cholesterol and acyl-glycerols for membrane formation and maintenance. Lipid droplets are found in all eukaryotic organisms and store a large portion of lipids in mammalian adipocytes. Initially, these lipid droplets were considered to merely serve as fat depots, but since the discovery in the 1990s of proteins in the lipid droplet coat that regulate lipid droplet dynamics and lipid metabolism, lipid droplets are seen as highly dynamic organelles that play a very important role in the regulation of intracellular lipid storage and lipid metabolism. The role of lipid droplets outside of lipid and cholesterol storage has recently begun to be elucidated and includes a close association to inflammatory responses through the synthesis and metabolism of eicosanoids and to metabolic disorders such as obesity, cancer,^[3]^[4] and atherosclerosis.^[5] In non-adipocytes, lipid droplets are known to play a role in protection from lipotoxicity by storage of fatty acids in the form of neutral triacylglycerol, which consists of three fatty acids bound to glycerol. Alternatively, fatty acids can be converted to lipid intermediates like diacylglycerol (DAG), ceramides and fatty acyl-CoAs. These lipid intermediates can impair insulin signaling, which is referred to as lipid-induced insulin resistance and lipotoxicity.^[6] Lipid droplets also serve as platforms for protein binding and degradation. Finally, lipid droplets are known to be exploited by pathogens such as the hepatitis C virus, the dengue virus and Chlamydia trachomatis among others.^[7]^[8]

^ Martin, Sally; Parton, Robert G. (8 March 2006). "Lipid droplets: a unified view of a dynamic organelle". Nature Reviews Molecular Cell Biology. 7 (5): 373–378. doi:10.1038/nrm1912. PMID 16550215. S2CID 34926182.
^ Mobilization and cellular uptake of stored fats and triacylglycerol (with Animation)
^ Bozza, PT; Viola, JP (Apr–Jun 2010). "Lipid droplets in inflammation, cancer". Prostaglandins, Leukotrienes, and Essential Fatty Acids. 82 (4–6): 243–50. doi:10.1016/j.plefa.2010.02.005. PMID 20206487.
^ Melo, Rossana C. N.; Dvorak, Ann M.; Chitnis, Chetan E. (5 July 2012). "Lipid Body–Phagosome Interaction in Macrophages during Infectious Diseases: Host Defense or Pathogen Survival Strategy?". PLOS Pathogens. 8 (7): e1002729. doi:10.1371/journal.ppat.1002729. PMC 3390411. PMID 22792061.
^ Greenberg, Andrew S.; Coleman, Rosalind A.; Kraemer, Fredric B.; McManaman, James L.; Obin, Martin S.; Puri, Vishwajeet; Yan, Qing-Wu; Miyoshi, Hideaki; Mashek, Douglas G. (1 June 2011). "The role of lipid droplets in metabolic disease in rodents and humans". Journal of Clinical Investigation. 121 (6): 2102–2110. doi:10.1172/JCI46069. PMC 3104768. PMID 21633178.
^ Bosma, M; Kersten, S; Hesselink, MKC; Schrauwen, P (2012). "Re-evaluating lipotoxic triggers in skeletal muscle: Relating intramyocellular lipid metabolism to insulin sensitivity" (PDF). Prog Lipid Res. 51 (1): 36–49. doi:10.1016/j.plipres.2011.11.003. PMID 22120643.
^ Heaton, N.S.; Randall, G (2010). "Dengue virus-induced autophagy regulates lipid metabolism". Cell Host Microbe. 8 (5): 422–32. doi:10.1016/j.chom.2010.10.006. PMC 3026642. PMID 21075353.
^ Suzuki, M.; Shinohara, Y.; Ohsaki, Y.; Fujimoto, T. (15 August 2011). "Lipid droplets: size matters". Journal of Electron Microscopy. 60 (supplement 1): S101–S116. doi:10.1093/jmicro/dfr016. PMID 21844583.

[1] Martin, Sally; Parton, Robert G. (8 March 2006). "Lipid droplets: a unified view of a dynamic organelle". Nature Reviews Molecular Cell Biology. 7 (5): 373–378. doi:10.1038/nrm1912. PMID 16550215. S2CID 34926182.

[mehta-2] Mobilization and cellular uptake of stored fats and triacylglycerol (with Animation)

[3] Bozza, PT; Viola, JP (Apr–Jun 2010). "Lipid droplets in inflammation, cancer". Prostaglandins, Leukotrienes, and Essential Fatty Acids. 82 (4–6): 243–50. doi:10.1016/j.plefa.2010.02.005. PMID 20206487.

[4] Melo, Rossana C. N.; Dvorak, Ann M.; Chitnis, Chetan E. (5 July 2012). "Lipid Body–Phagosome Interaction in Macrophages during Infectious Diseases: Host Defense or Pathogen Survival Strategy?". PLOS Pathogens. 8 (7): e1002729. doi:10.1371/journal.ppat.1002729. PMC 3390411. PMID 22792061.

[5] Greenberg, Andrew S.; Coleman, Rosalind A.; Kraemer, Fredric B.; McManaman, James L.; Obin, Martin S.; Puri, Vishwajeet; Yan, Qing-Wu; Miyoshi, Hideaki; Mashek, Douglas G. (1 June 2011). "The role of lipid droplets in metabolic disease in rodents and humans". Journal of Clinical Investigation. 121 (6): 2102–2110. doi:10.1172/JCI46069. PMC 3104768. PMID 21633178.

[6] Bosma, M; Kersten, S; Hesselink, MKC; Schrauwen, P (2012). "Re-evaluating lipotoxic triggers in skeletal muscle: Relating intramyocellular lipid metabolism to insulin sensitivity" (PDF). Prog Lipid Res. 51 (1): 36–49. doi:10.1016/j.plipres.2011.11.003. PMID 22120643.

[7] Heaton, N.S.; Randall, G (2010). "Dengue virus-induced autophagy regulates lipid metabolism". Cell Host Microbe. 8 (5): 422–32. doi:10.1016/j.chom.2010.10.006. PMC 3026642. PMID 21075353.

[8] Suzuki, M.; Shinohara, Y.; Ohsaki, Y.; Fujimoto, T. (15 August 2011). "Lipid droplets: size matters". Journal of Electron Microscopy. 60 (supplement 1): S101–S116. doi:10.1093/jmicro/dfr016. PMID 21844583.

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