Compositions and methods for modifying the content of polyunsaturated fatty acids in mammalian cells

Abstract

The present invention features compositions (e.g., nucleic acids encoding fat-1, optionally and operably linked to a constitutively active or tissue-specific promoter or other regulatory sequence) and pharmaceutically acceptable formulations including nucleic acids encoding fat-1 or biologically active variants thereof and methods that can be used to effectively modify the content of PUFAs in animal cells (i.e., cells other than those of C. elegans , for example, mammalian cells such as myocytes, neurons (whether of the peripheral or central nervous system), adipocytes, endothelial cells, and cancer cells). The modified cells, whether in vivo or ex vivo (e.g., in tissue culture), transgenic animals containing them, and food products obtained from those animals (e.g., meat or other edible parts of the animals (e.g., liver, kidney, or sweetbreads)) are also within the scope of the present invention.

1 . An isolated nucleic acid molecule comprising a first and a second nucleic acid sequence, wherein the first sequence encodes an enzyme that desaturates an ω-6 fatty acid to a corresponding ω-3 fatty acid and the second sequence is a tissue-specific promoter that directs expression of the first sequence in a selected mammalian cell type. 
     
     
         2 . The nucleic acid molecule of  claim 1 , wherein the mammalian cell type is a myocyte, endothelial cell, adipose cell, or neuron. 
     
     
         3 . The nucleic acid molecule of  claim 1 , wherein the mammalian cell type is a type of cancer cell. 
     
     
         4 . An expression vector comprising the nucleic acid molecule of  claim 1 . 
     
     
         5 . A mammalian cell comprising the vector of  claim 4 . 
     
     
         6 . A transgenic mammal comprising the cDNA sequence shown in  FIG. 17A , or a biologically active fragment or mutant thereof. 
     
     
         7 . A method of improving the content of ω-3 fatty acids in a patient's diet, the method comprising providing to the patient a food product obtained from a transgenic mammal that expresses a fat-1 gene of a non-mammalian animal, or a biologically active fragment or variant thereof. 
     
     
         8 . A method of treating a patient who has cancer, the method comprising administering to the patient a therapeutically effective amount of the nucleic acid molecule of  claim 1 , wherein the tissue-specific promoter directs expression of the sequence encoding the enzyme in the patient's cancerous cells. 
     
     
         9 . The method of  claim 8 , wherein the cancerous cells are breast cancer cells or colon cancer cells. 
     
     
         10 . A method of inhibiting neuronal cell death in a patient, the method comprising administering to the patient a therapeutically effective amount of the nucleic acid molecule of  claim 1 , wherein the tissue-specific promoter directs expression of the sequence encoding the enzyme in neurons. 
     
     
         11 . The method of  claim 10 , wherein the patient has a neurodegenerative disease. 
     
     
         12 . The method of  claim 11 , wherein the neurodegenerative disease is Alzheimer's disease, Parkinson's disease, or Huntington's disease. 
     
     
         13 . A method of treating a patient who has, or who may develop, a condition associated with an insufficiency of n-3 polyunsaturated fatty acid (PUFA) or an imbalance in the ratio of n-3:n-6 PUFAs, the method comprising administering to the patient a nucleic acid encoding an n-3 desaturase or a biologically active variant thereof. 
     
     
         14 . The method of  claim 13 , wherein the condition is an arrhythmia, cardiovascular disease, cancer, an inflammatory disease, an autoimmune diseases, a malformation or threatened malformation of the retina or brain, diabetes, obesity, a skin disorder, a renal disease, ulcerative colitis, Crohn's disease, or chronic obstructive pulmonary disease. 
     
     
         15 . A method of treating a patient who has received, or who is scheduled to receive, a transplant comprising a biological organ, tissue, or cell, the method comprising administering to either the patient or to the transplant, a nucleic acid encoding an n-3 desaturase or a biologically active variant thereof.