Methods and compositions for modulating gluconeogenesis using PGC-1

Abstract

The invention provides novel methods and compositions for modulating gluconeogenesis through modulation of PGC-1 activity or expression. Also provided are methods for identifying compounds that modulate gluconeogenesis through modulation of PGC-1 activity or expression, as well as methods for identifying compounds that modulate the interaction of PGC-1 with PGC-1 target molecules. Further provided are methods for treating disorders characterized by aberrant gluconcogenesis.

What is claimed:  
     
         1 . A method for modulating gluconeogenesis comprising contacting a cell with an agent that modulates PGC-1 expression or activity, such that gluconeogenesis is modulated.  
     
     
         2 . The method of  claim 1 , wherein PGC-1 expression or activity is increased.  
     
     
         3 . The method of  claim 1 , wherein PGC-1 expression or activity is decreased.  
     
     
         4 . The method of  claim 1 , wherein gluconeogenesis is increased  
     
     
         5 . The method of  claim 1 , wherein gluconeogenesis is decreased.  
     
     
         6 . The method of  claim 1 , wherein the agent is a PGC-1 nucleic acid molecule.  
     
     
         7 . The method of  claim 6 , wherein the PGC-1 nucleic acid molecule is derived from a human.  
     
     
         8 . The method of  claim 7 , wherein the PGC-1 nucleic acid molecule comprises the nucleic acid sequence of SEQ ID NO: 4.  
     
     
         9 . The method of  claim 8 , wherein nucleotides 518-532 of SEQ ID NO: 4 are deleted.  
     
     
         10 . The method of  claim 6 , wherein the PGC-1 nucleic acid molecule encodes a dominant negative PGC-1 polypeptide.  
     
     
         11 . The method of  claim 10 , wherein the dominant negative PGC-1 polypeptide has a mutated LXXLL motif.  
     
     
         12 . The method of  claim 11 , wherein at least one amino acid residue of the LXXLL motif is deleted.  
     
     
         13 . The method of  claim 11 , wherein at least one leucine residue in the LXXLL motif is substituted with another amino acid residue.  
     
     
         14 . The method of  claim 13 , wherein the leucine residue at the fourth position of the LXXLL motif is substituted with alanine.  
     
     
         15 . The method of  claim 6 , wherein the PGC-1 nucleic acid molecule is an antisense PGC-1 nucleic acid molecule.  
     
     
         16 . The method of  claim 6 , wherein the PGC-1 nucleic acid molecule is contained within a vector.  
     
     
         17 . The method of  claim 16 , wherein the vector is an adenoviral vector.  
     
     
         18 . The method of  claim 1 , wherein the agent is a PGC-1 polypeptide.  
     
     
         19 . The method of  claim 18 , wherein the PGC-1 polypeptide is derived from a human.  
     
     
         20 . The method of  claim 19 , wherein the PGC-1 polypeptide comprises the amino acid sequence of SEQ ID NO: 5.  
     
     
         21 . The method of  claim 20 , wherein residues 144-148 of SEQ ID NO: 5 are deleted.  
     
     
         22 . The method of  claim 18 , wherein the PGC-1 polypeptide is a dominant negative PGC-1 polypeptide.  
     
     
         23 . The method of  claim 22 , wherein the dominant negative PGC-1 polypeptide has a mutated LXXLL motif.  
     
     
         24 . The method of  claim 23 , wherein at least one amino acid residue of the LXXLL motif is deleted.  
     
     
         25 . The method of  claim 23 , wherein at least one leucine residue in the LXXLL motif is substituted with another amino acid residue.  
     
     
         26 . The method of  claim 25 , wherein the leucine residue at the fourth position of the LXXLL motif is substituted with alanine.  
     
     
         27 . The method of  claim 1 , wherein the agent is a polypeptide that binds to PGC-1.  
     
     
         28 . The method of  claim 1 , wherein the agent is a small molecule.  
     
     
         29 . The method of  claim 1 , wherein the interaction between PGC-1 and HNF-4α is decreased.  
     
     
         30 . The method of  claim 1 , wherein the cell is a hepatocyte.  
     
     
         31 . The method of  claim 30 , wherein the hepatocyte is selected from the group consisting of a primary hepatocyte and a Fao hepatoma cell.  
     
     
         32 . The method of  claim 1 , wherein the method is performed in vitro.  
     
     
         33 . The method of  claim 1 , wherein the method is performed in vivo.  
     
     
         34 . A method for identifying a compound capable of modulating gluconeogenesis comprising: 
 a) contacting a cell with a compound; and    b) determining whether PGC-l expression or activity is modulated.    
     
     
         35 . The method of  claim 34 , wherein PGC-1 expression or activity is increased.  
     
     
         36 . The method of  claim 34 , wherein PGC-1 expression or activity is decreased.  
     
     
         37 . The method of  claim 34 , wherein PGC-1 expression is measured by Northern blotting.  
     
     
         38 . The method of  claim 34 , wherein determining whether PGC-1 activity is modulated comprises determining whether expression of at least one of phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase is modulated.  
     
     
         39 . The method of  claim 38 , wherein expression is measured by Northern blotting.  
     
     
         40 . The method of  claim 38 , wherein expression is measured by measuring the expression or activity of a reporter construct comprising the promoter/enhancer region from at least one of the phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase genes, operatively linked to a nucleic acid molecule encoding a reporter gene.  
     
     
         41 . The method of  claim 34 , wherein determining whether PGC-1 activity is modulated comprises determining whether glucose output from the cell is modulated.  
     
     
         42 . The method of  claim 34 , wherein the cell is a hepatocyte.  
     
     
         43 . The method of  claim 42 , wherein the hepatocyte is selected from the group consisting of a primary hepatocyte and a Fao hepatoma cell.  
     
     
         44 . A method for identifying a compound capable of treating a disorder characterized by aberrant gluconeogenesis comprising assaying the ability of the compound to modulate the expression or activity of PGC-1 to thereby identify a compound capable of treating a disorder characterized by aberrant gluconcogenesis.  
     
     
         45 . The method of  claim 44 , wherein the disorder is a disorder characterized by overproduction of glucose.  
     
     
         46 . The method of  claim 45 , wherein the disorder is diabetes.  
     
     
         47 . The method of  claim 46 , wherein the diabetes is selected from the group consisting of: type 1 diabetes, type 2 diabetes, and maturity onset diabetes of the young.  
     
     
         48 . The method of  claim 45 , wherein the disorder is obesity.  
     
     
         49 . The method of  claim 44 , wherein the disorder is a disorder characterized by underproduction of glucose.  
     
     
         50 . A method for identifying a compound which inhibits the interaction of the PGC-1 protein with a target molecule comprising contacting, in the presence of the compound, the PGC-1 protein and the target molecule under conditions which allow binding of the target molecule to the PGC-1 protein to form a complex; and detecting the formation of a complex of the PGC-1 protein and the target molecule in which the ability of the compound to inhibit interaction between the PGC-1 protein and the target molecule is indicated by a decrease in complex formation as compared to the amount of complex formed in the absence of the compound.  
     
     
         51 . The method of  claim 50 , wherein the target molecule is HNF-4α.  
     
     
         52 . The method of  claim 50 , wherein the target molecule is the phosphoenolpyruvate carboxykinase promoter.  
     
     
         53 . A method for treating subject having a disorder characterized by aberrant gluconeogenesis comprising administering to the subject an agent capable of modulating PGC-1 expression or activity, such that the disorder is treated.  
     
     
         54 . The method of  claim 53 , wherein the disorder is a disorder characterized by overproduction of glucose.  
     
     
         55 . The method of  claim 54 , wherein the disorder is diabetes.  
     
     
         56 . The method of  claim 55 , wherein the diabetes is selected from the group consisting of: type 1 diabetes, type 2 diabetes, and maturity onset diabetes of the young.  
     
     
         57 . The method of  claim 54 , wherein the disorder is obesity.  
     
     
         58 . The method of  claim 53 , wherein the disorder is a disorder characterized by underproduction of glucose.  
     
     
         59 . The method of  claim 54 , wherein PGC-1 expression or activity is decreased.  
     
     
         60 . The method of  claim 58 , wherein PGC-1 expression or activity is increased.  
     
     
         61 . The method of  claim 54 , wherein gluconeogenesis is decreased.  
     
     
         62 . The method of  claim 58 , wherein gluconeogenesis is increased.  
     
     
         63 . The method of  claim 53 , wherein the agent is a PGC-1 nucleic acid molecule.  
     
     
         64 . The method of  claim 63 , wherein the PGC-1 nucleic acid molecule is derived from a human.  
     
     
         65 . The method of  claim 64 , wherein the PGC-1 nucleic acid molecule comprises the nucleic acid sequence of SEQ ID NO: 4.  
     
     
         66 . The method of  claim 65 , wherein nucleotides 518-532 of SEQ ID NO: 4 are deleted.  
     
     
         67 . The method of  claim 63 , wherein the PGC-1 nucleic acid molecule is an antisense PGC-1 nucleic acid molecule.  
     
     
         68 . The method of  claim 63 , wherein the PGC-1 nucleic acid molecule encodes a dominant negative PGC-1 polypeptide.  
     
     
         69 . The method of  claim 68  wherein the dominant negative PGC-1 polypeptide has a mutated LXXLL motif.  
     
     
         70 . The method of  claim 69 , wherein at least one amino acid residue of the LXXLL motif is deleted.  
     
     
         71 . The method of  claim 69 , wherein at least one leucine residue in the LXXLL motif is substituted with another amino acid residue.  
     
     
         72 . The method of  claim 71 , wherein the leucine residue at the fourth position of the LXXLL motif is substituted with alanine.  
     
     
         73 . The method of  claim 63 , wherein the PGC-1 nulceic acid molecule is contained within a vector.  
     
     
         74 . The method of  claim 73 , wherein the vector is an adenoviral vector.  
     
     
         75 . A compound identified by the method of  claim 34 .  
     
     
         76 . A compound identified by the method of  claim 44 .  
     
     
         77 . A compound identified by the method of  claim 50.