Chinese hamster ovary cells overexpressing the oxysterol binding protein (OSBP) display enhanced synthesis of sphingomyelin in response to 25-hydroxycholesterol

• Published in: Journal of lipid research 1999-01, Vol.40 (1), p.109-116
• Main Authors: Lagace, T A, Byers, D M, Cook, H W, Ridgway, N D
• Format: Article
• Language: English
• Subjects: 25-hydroxycholesterol; Animals; ceramide; Ceramides - metabolism; CHO Cells; Cholesterol - biosynthesis; Cholesterol Esters - biosynthesis; Cricetinae; Gene Expression; Golgi Apparatus - metabolism; Hydroxycholesterols - pharmacology; Kinetics; oxysterol binding protein; Receptors, Steroid - genetics; Receptors, Steroid - metabolism; sphingomyelin; Sphingomyelins - biosynthesis; Transfection
• ISSN: 0022-2275
• DOI: 10.1016/s0022-2275(20)33345-9

25-Hydroxycholesterol negatively regulates cholesterol synthesis and activates cholesterol esterification in a variety of cultured cells. Concurrent with these effects, 25-hydroxycholesterol also stimulates the synthesis of sphingomyelin in Chinese hamster ovary (CHO)-K1 cells. The role of oxysterol binding protein (OSBP), a high affinity receptor for 25-hydroxycholesterol, in activation of SM synthesis was assessed by overexpression in CHO-K1 cells. When compared to mock transfected controls, three CHO-K1 clones overexpressing OSBP by 10- to 15-fold displayed a 2- to 3-fold enhancement of [3H]serine incorporation into sphingomyelin when treated with 25-hydroxycholesterol. Closer examination of one of these clones (CHO-OSBP cells) revealed a >8.5-fold stimulation of sphingomyelin synthesis after a 6-h treatment with 25-hydroxycholesterol compared to 3.5-fold in controls, slightly higher basal levels of sphingomyelin synthesis, and a more rapid response to 25-hydroxycholesterol. [3H]serine incorporation into phosphatidylserine, phosphatidylethanolamine, ceramide, or glucosylceramide was affected by