title: Cholesterol ester droplets and steroidogenesis.
abstract: Intracellular lipid droplets (LDs) are dynamic organelles that contain a number of associated proteins including perilipin (Plin) and vimentin. Cholesteryl ester (CE)-rich LDs normally accumulate in steroidogenic cells and their mobilization is the preferred initial source of cholesterol for steroidogenesis. Plin1a, 1b and 5 were found to preferentially associate with triacylglycerol-rich LDs and Plin1c and Plin4 to associate with CE-rich LDs, but the biological significance of this remains unanswered. Vimentin null mice were found to have decreased ACTH-stimulated corticosterone levels, and decreased progesterone levels in females, but normal hCG-stimulated testosterone levels in males. Smaller LDs were seen in null cells. Lipoprotein cholesterol delivery to adrenals and ovary was normal, as was the expression of steroidogenic genes; however, the movement of cholesterol to mitochondria was reduced in vimentin null mice. These results suggest that vimentin is important in the maintenance of CE-rich LDs and in the movement of cholesterol for steroidogenesis.
authors.affiliation: VA Palo Alto Health Care System, Palo Alto, CA 94304, USA. fbk@stanford.edu
authors.forename: Fredric B
authors.initials: FB
authors.lastname: Kraemer
authors.forename: Victor K
authors.initials: VK
authors.lastname: Khor
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Shen
authors.forename: Salman
authors.initials: S
authors.lastname: Azhar
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002788:Cholesterol Esters / Q000737:chemistry*; D003345:Corticosterone / Q000097:blood; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D000070778:Perilipin-1; D000071229:Perilipin-4; D000070797:Perilipin-5; D010750:Phosphoproteins / Q000378:metabolism; D011374:Progesterone / Q000097:blood; D011506:Proteins / Q000378:metabolism; D013256:Steroids / Q000096:biosynthesis*; D013739:Testosterone / Q000097:blood; D014746:Vimentin / Q000172:deficiency* / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D002788:Cholesterol Esters; C560544:PLIN4 protein, human; D000070778:Perilipin-1; D000071229:Perilipin-4; D000070797:Perilipin-5; D010750:Phosphoproteins; C511805:Plin5 protein, mouse; D011506:Proteins; D013256:Steroids; D014746:Vimentin; D013739:Testosterone; D011374:Progesterone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone