Cloning of a Unique Lipase from Endothelial Cells Extends the Lipase Gene Family

Abstract

A new lipoprotein lipase-like gene has been cloned from endothelial cells through a subtraction methodology aimed at characterizing genes that are expressed with in vitro differentiation of this cell type. The conceptual endothelial cell-derived lipase protein contains 500 amino acids, including an 18-amino acid hydrophobic signal sequence, and is 44% identical to lipoprotein lipase and 41% identical to hepatic lipase. Comparison of primary sequence to that of lipoprotein and hepatic lipase reveals conservation of the serine, aspartic acid, and histidine catalytic residues as well as the 10 cysteine residues involved in disulfide bond formation. Expression was identified in cultured human umbilical vein endothelial cells, human coronary artery endothelial cells, and murine endothelial-like yolk sac cells by Northern blot. In addition, Northern blot and in situ hybridization analysis revealed expression of the endothelial-derived lipase in placenta, liver, lung, ovary, thyroid gland, and testis. A c-Myc-tagged protein secreted from transfected COS7 cells had phospholipase A1 activity but no triglyceride lipase activity. Its tissue-restricted pattern of expression and its ability to be expressed by endothelial cells, suggests that endothelial cell-derived lipase may have unique functions in lipoprotein metabolism and in vascular disease.

The role of lipoprotein lipase in adipose tissue development and metabolism

“…These include the increased receptor-mediated uptake of whole lipoprotein particles (eg VLDL receptor) as well as the action of alternative lipases such as the recently discovered endothelial derived lipase. 17,18 LPL-de®cient SM and AT…”

Lipasa endotelial y su relación con la enfermedad cardiovascular y diabetes mellitus tipo 2

“…Esta nueva enzima se ha relacionado con el proceso de aterogénesis, principalmente por su participación en la modulación de las concentraciones plasmática de colesterol HDL (c-HDL) 2,3 .…”

“…Lipasa endotelial: estructura y síntesis LE es una enzima de 482 aminoácidos que se identifi có inicialmente en cultivo de células endoteliales de cordón umbilical humano (HUVEC) y en líneas celulares de macrófagos humanos THP-1 expuestos a LDL oxidadas 2,3 .…”

Identification of a Lipoprotein Lipase Cofactor-binding Site by Chemical Cross-linking and Transfer of Apolipoprotein C-II-responsive Lipolysis from Lipoprotein Lipase to Hepatic Lipase

“…Chinese hamster ovary Pro5 cells were maintained in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and antibiotics (Invitrogen). To mediate the transfection of Chinese hamster ovary cells, coprecipitates of plasmid DNA and CaPO 4 were prepared (28). The calcium phosphate/DNA mixture was incubated at room temperature for 30 min before it was added to a 50% confluent Chinese hamster ovary monolayer.…”

“…Hepatic lipase (HL) 1 and lipoprotein lipase (LPL) are members of the same lipase gene family, along with pancreatic lipase, the pancreatic lipase-related lipases, endothelial lipase, and phosphatidylserine-specific phospholipase A 1 (1)(2)(3)(4)(5)(6). Through their ability to hydrolyze triglycerides and phospholipids in a variety of circulating plasma lipoproteins, including chylomicrons and very low, intermediate, and high density lipoproteins, HL and LPL greatly influence lipid metabolism (7)(8)(9).…”