Accumulation of cholesteryl esters as cytoplasmic lipid droplets within cells of human aortic tissue is a characteristic feature of early lesions of atherosclerotic plaque. These cholesteryl esters are produced through biochemical reaction catalyzed by the enzyme acyl coenzyme A:cholesterol acyltransferase (ACAT). In intestines of vertebrate animals, including human, the extent of absorption of dietary cholesterol can be shown to be significantly reduced by inhibiting intestinal ACAT activity. In livers of vertebrate animals, formation of lipoproteins require proper supply of cholesteryl esters produced through ACAT reaction. For these reasons, many pharmaceutical companies in the United States and abroad are in the process of developing specific chemical reagents to inhibit ACAT activity for the purpose of therapeutic prevention/treatment of human hypercholesterolemia and human atherosclerosis. ACAT is a membrane-bound enzyme located in the endoplasmic reticulum of various tissues of animal and human cells. It has never been purified to homogeneity while still retaining biological activity. The protein structure as well as its amino acid composition or amino acid sequence of ACAT is at present unknown. The structure of genomic DNA or the nucleotide sequence of cDNA encoding the ACAT gene has never been reported in literature.
Dartmouth researchers cloned a new human cDNA (K1) which, when ligated with mammalian expression vector (pcDNA1) and transfected into mammalian cells, expresses human-specific acyl coenzyme A:cholesterol acyltransferase (ACAT) activity in intact cells and in cell-free extracts. In particular, a stable transfectant clone (14e) has been shown to express high levels of human ACAT activity assayed by various means. This invention thus enables the investigators to use K1 cDNA or any derivative of this cDNA to express large amounts of human ACAT activity in intact mammalian cells and in various cell-free systems for the purpose of screening and testing for chemical agents serving as specific ACAT inhibitors to be developed for therapeutic prevention/treatment of hypercholesterolemia, human atherosclerosis, and other diseases arising from high cholesterol levels.
This clone is covered by Dartmouth's issued Untied States Patent No. 5,484,727. The entire ACAT gene, isolated, cloned, and sequenced in Dartmouth laboratories is covered in the issued United States Patent No. 5,834,283. The utility of these materials is claimed in the issued United States Patent No. 5,968,749. We are seeking an industrial partner to further refine and market this technology. (Ref: J4)
Last Updated: 7/24/12