Biomaterial Database

A role for high density lipoproteins in hepatic phosphatidylcholine homeostasis. 2007

Zhaoyu Li, and Luis B Agellon, and Dennis E Vance

Department of Biochemistry and Canadian Institutes of Health Research Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.

Choline is (95%) found largely in the biosphere as a component of phosphatidylcholine (PC) which is made from choline via the CDP-choline pathway. Animals obtain choline from both the diet and via endogenous biosynthesis that involves the conversion of phosphatidylethanolamine into PC by phosphatidylethanolamine N-methyltransferase (PEMT), followed by PC catabolism. We have uncovered a striking gender-specific conservation of choline in female mice that does not occur in male mice. Female Pemt(-/-) mice maintained hepatic PC/total choline levels during the first day of choline deprivation and escaped liver damage whereas male Pemt(-/-) mice did not. Plasma PC levels in high-density lipoproteins (HDLs) were higher in male Pemt(-/-) mice than those in females before choline deprivation. Interestingly, after choline deprivation for 1 day, female, but not male, Pemt(-/-) mice increased HDL-PC levels. Glybenclamide, an inhibitor of PC efflux mediated by ABC transporters, eliminated this response to choline deprivation in females. These data suggest that (i) increased PC efflux from extra-hepatic tissues to HDLs in the circulation provided sufficient choline for the liver and compensated for loss of hepatic PC during the initial stages of choline deprivation in female, but not male, Pemt(-/-) mice, and (ii) plasma HDL in female mice has an important function in maintenance of hepatic PC as an acute response to severe choline deprivation.

UI	MeSH Term	Description	Entries
D008075	Lipoproteins, HDL	A class of lipoproteins of small size (4-13 nm) and dense (greater than 1.063 g/ml) particles. HDL lipoproteins, synthesized in the liver without a lipid core, accumulate cholesterol esters from peripheral tissues and transport them to the liver for re-utilization or elimination from the body (the reverse cholesterol transport). Their major protein component is APOLIPOPROTEIN A-I. HDL also shuttle APOLIPOPROTEINS C and APOLIPOPROTEINS E to and from triglyceride-rich lipoproteins during their catabolism. HDL plasma level has been inversely correlated with the risk of cardiovascular diseases.	High Density Lipoprotein,High-Density Lipoprotein,High-Density Lipoproteins,alpha-Lipoprotein,alpha-Lipoproteins,Heavy Lipoproteins,alpha-1 Lipoprotein,Density Lipoprotein, High,HDL Lipoproteins,High Density Lipoproteins,Lipoprotein, High Density,Lipoprotein, High-Density,Lipoproteins, Heavy,Lipoproteins, High-Density,alpha Lipoprotein,alpha Lipoproteins
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008107	Liver Diseases	Pathological processes of the LIVER.	Liver Dysfunction,Disease, Liver,Diseases, Liver,Dysfunction, Liver,Dysfunctions, Liver,Liver Disease,Liver Dysfunctions
D008297	Male		Males
D008810	Mice, Inbred C57BL	One of the first INBRED MOUSE STRAINS to be sequenced. This strain is commonly used as genetic background for transgenic mouse models. Refractory to many tumors, this strain is also preferred model for studying role of genetic variations in development of diseases.	Mice, C57BL,Mouse, C57BL,Mouse, Inbred C57BL,C57BL Mice,C57BL Mice, Inbred,C57BL Mouse,C57BL Mouse, Inbred,Inbred C57BL Mice,Inbred C57BL Mouse
D010713	Phosphatidylcholines	Derivatives of PHOSPHATIDIC ACIDS in which the phosphoric acid is bound in ester linkage to a CHOLINE moiety.	Choline Phosphoglycerides,Choline Glycerophospholipids,Phosphatidyl Choline,Phosphatidyl Cholines,Phosphatidylcholine,Choline, Phosphatidyl,Cholines, Phosphatidyl,Glycerophospholipids, Choline,Phosphoglycerides, Choline
D010714	Phosphatidylethanolamines	Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.	Cephalin,Cephalins,Ethanolamine Phosphoglyceride,Ethanolamine Phosphoglycerides,Ethanolamineglycerophospholipids,Phosphoglyceride, Ethanolamine,Phosphoglycerides, Ethanolamine
D002796	Choline Deficiency	A condition produced by a deficiency of CHOLINE in animals. Choline is known as a lipotropic agent because it has been shown to promote the transport of excess fat from the liver under certain conditions in laboratory animals. Combined deficiency of choline (included in the B vitamin complex) and all other methyl group donors causes liver cirrhosis in some animals. Unlike compounds normally considered as vitamins, choline does not serve as a cofactor in enzymatic reactions. (From Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)	Deficiency, Choline,Choline Deficiencies,Deficiencies, Choline
D005260	Female		Females
D005905	Glyburide	An antidiabetic sulfonylurea derivative with actions like those of chlorpropamide	Glibenclamide,Daonil,Diabeta,Euglucon 5,Euglucon N,Glybenclamide,HB-419,HB-420,Maninil,Micronase,Neogluconin,HB 419,HB 420,HB419,HB420