Biomaterial Database

Effect of positively charged sphingomyelin liposomes on cholesterol metabolism of cells in culture. 1983

B J Kudchodkar, and J J Albers, and E L Bierman

When cultured human skin fibroblasts were incubated at 37 degrees C with sonically dispersed positively charged sphingomyelin liposomes, sphingomyelin accumulated within the cell. This resulted in stimulation of cholesterol synthesis by increasing 3-hydroxy-3-methylglutaryl Coenzyme A reductase activity. Activation was rapid and was not due to the efflux of cell cholesterol or to cell growth and proliferation. Neither low density lipoprotein cholesterol nor nonlipoprotein cholesterol could suppress the sphingomyelin-induced cholesterol synthesis or activate the acyl-CoA cholesterol acyltransferase, despite an increase in cell cholesterol content. In contrast, the response to 7-ketocholesterol or 26-hydroxycholesterol was not impaired. The effect of sphingomyelin on cholesterol synthesis was temporary and reversible. Twenty-four hours after removal of sphingomyelin, cholesterol synthesis returned to normal and could be suppressed by LDL. Accumulation of sphingomyelin in the cell decreased lysosomal cholesteryl ester hydrolase but had no effect on the microsomal cholesteryl ester hydrolase. These results suggest that accumulation of sphingomyelin in the cell markedly affects cellular cholesterol homeostasis. Resultant accumulation of cholesteryl esters in the presence of extracellular cholesterol could be relevant to atherogenesis.

UI	MeSH Term	Description	Entries
D008081	Liposomes	Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.	Niosomes,Transferosomes,Ultradeformable Liposomes,Liposomes, Ultra-deformable,Liposome,Liposome, Ultra-deformable,Liposome, Ultradeformable,Liposomes, Ultra deformable,Liposomes, Ultradeformable,Niosome,Transferosome,Ultra-deformable Liposome,Ultra-deformable Liposomes,Ultradeformable Liposome
D008247	Lysosomes	A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured or undergoes MEMBRANE FUSION. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed).	Autolysosome,Autolysosomes,Lysosome
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D002788	Cholesterol Esters	Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis.	Cholesterol Ester,Cholesteryl Ester,Cholesteryl Esters,Ester, Cholesterol,Ester, Cholesteryl,Esters, Cholesterol,Esters, Cholesteryl
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006903	Hydroxymethylglutaryl CoA Reductases	Enzymes that catalyze the reversible reduction of alpha-carboxyl group of 3-hydroxy-3-methylglutaryl-coenzyme A to yield MEVALONIC ACID.	HMG CoA Reductases,3-Hydroxy-3-methylglutaryl CoA Reductase,HMG CoA Reductase,Hydroxymethylglutaryl CoA Reductase,3 Hydroxy 3 methylglutaryl CoA Reductase,CoA Reductase, 3-Hydroxy-3-methylglutaryl,Reductase, 3-Hydroxy-3-methylglutaryl CoA
D013109	Sphingomyelins	A class of sphingolipids found largely in the brain and other nervous tissue. They contain phosphocholine or phosphoethanolamine as their polar head group so therefore are the only sphingolipids classified as PHOSPHOLIPIDS.	Sphingomyelin