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  • Cholesterol ester droplets ...
    Kraemer, Fredric B.; Khor, Victor K.; Shen, Wen-Jun; Azhar, Salman

    Molecular and cellular endocrinology, 05/2013, Volume: 371, Issue: 1-2
    Journal Article

    ► Cholesteryl ester-rich and triacylglycerol-rich lipid droplets have unique expression of perilipin family members. ► Vimentin is associated with lipid droplets. ► Vimentin deficiency results in defective ACTH-stimulated corticosterone production. ► Vimentin deficiency impairs cholesterol movement to mitochondria. 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.