Depigmenting activity of agouti signal protein and peptides thereof

Abstract

The invention is an agouti signaling protein and peptides as well as pharmaceutical compositions thereof and their use in methods of inhibiting melanin production by melanocytes. The agouti signaling protein and peptides thereof are useful in cosmetics and in clinical prevention and treatment of hyperpigmentary conditions. Methods for screening peptides for melanogenesis inhibiting activity are also provided.

What is claimed is:  
     
         1 . A purified biologically active peptide of the agouti signaling protein which has depigmenting activity.  
     
     
         2 . A purified biologically active peptide of the agouti signaling protein which has the following characteristics: 
 (a) the peptide has depigmenting activity due to its ability to inhibit the production of at least one melanin;    (b) the peptide has at least one region selected from the group consisting of: 
 (i) at least one of a basic region derived from the full length agouti signaling protein or a portion thereof, and  
 (ii) a cysteine rich region derived from the full length agouti signaling protein or a portion thereof,  
   (c) the peptide has a minimum length of at least about 5 amino acid residues but has a maximum length selected from the group consisting of: 
 (i) no more than about 131 amino acid residues,  
 (ii) no more than about 109 amino acid residues;  
 (iii) no more than about 50 amino acid residues;  
 (iv) no more than about 20 amino acid residues; and  
 (v) no more than about 10 amino acid residues; and  
 wherein said agouti signaling protein is optionally coupled to a molecule which would facilitate its transport into cells.  
   
     
     
         3 . The agouti signaling protein of  claim 2  having a maximum length of no more than about 131 amino acid residues.  
     
     
         4 . The agouti signaling protein of  claim 3  having a maximum length of no more than about 109 amino acid residues.  
     
     
         5 . The peptide of  claim 1 , having the sequence of SEQ ID NO:1.  
     
     
         6 . The peptide of  claim 1 , having the sequence of SEQ ID NO:2.  
     
     
         7 . The peptide of  claim 1 , having the sequence of SEQ ID NO:3.  
     
     
         8 . The peptide of  claim 1 , having the sequence of SEQ ID NO:4.  
     
     
         9 . The peptide of  claim 1 , having the sequence of SEQ ID NO:5.  
     
     
         10 . The peptide of  claim 1 , having the sequence of SEQ ID NO:6  
     
     
         11 . The peptide of  claim 1 , having the sequence of SEQ ID NO:7.  
     
     
         12 . The peptide of  claim 1 , having the sequence of SEQ ID NO:8.  
     
     
         13 . The peptide of  claim 1 , having the sequence of SEQ ID NO:9.  
     
     
         14 . The peptide of  claim 1 , having the sequence of SEQ ID NO:10.  
     
     
         15 . The peptide of  claim 1 , having the sequence of SEQ ID NO:11.  
     
     
         16 . The peptide of  claim 1 , having the sequence of SEQ ID NO:12.  
     
     
         17 . The peptide of  claim 1 , having the sequence of SEQ ID NO:13.  
     
     
         18 . The peptide of  claim 1 , having the sequence of SEQ ID NO:14.  
     
     
         19 . The peptide of  claim 1 , having the sequence of SEQ ID NO:15.  
     
     
         20 . The peptide of  claim 1 , having the sequence of SEQ ID NO:16.  
     
     
         21 . The peptide of  claim 1 , having the sequence of SEQ ID NO:17.  
     
     
         22 . The peptide of  claim 1 , having the sequence of SEQ ID NO:18.  
     
     
         23 . The peptide of  claim 1 , having the sequence of SEQ ID NO:19.  
     
     
         24 . The peptide of  claim 1 , having the sequence of SEQ ID NO:20.  
     
     
         25 . The peptide of  claim 1 , having the sequence of SEQ ID NO:21.  
     
     
         26 . The peptide of  claim 1 , having the sequence of SEQ ID NO:22.  
     
     
         27 . The peptide of  claim 1 , having the sequence of SEQ ID NO:23.  
     
     
         28 . The peptide of  claim 1 , having the sequence of SEQ ID NO:24.  
     
     
         29 . The peptide of  claim 1 , having the sequence of SEQ ID NO:25.  
     
     
         30 . The peptide of  claim 1 , having the sequence of SEQ ID NO:26.  
     
     
         31 . The peptide of  claim 1 , having the sequence of SEQ ID NO:27.  
     
     
         32 . The peptide of  claim 1 , having the sequence of SEQ ID NO:28.  
     
     
         33 . The peptide of  claim 1 , having the sequence of SEQ ID NO:29.  
     
     
         34 . A composition-comprising the agouti signaling protein or biologically active peptide thereof and a pharmaceutically acceptable carrier.  
     
     
         35 . A purified polyclonal antibody that specifically binds the peptide of  claim 33 .  
     
     
         36 . A purified monoclonal antibody that specifically binds the peptide of  claim 33 .  
     
     
         37 . A method of down-regulating in a subject a melanogenic enzyme involved in melanin synthesis, comprising administering to the subject an amount of the agouti signaling protein or a biologically active peptide thereof to down-regulate the melanogenic enzyme.  
     
     
         38 . A method of reducing melanin synthesis in a subject comprising administering to the subject an amount of the agouti signaling protein or a biologically active peptide thereof to reduce melanin synthesis.  
     
     
         39 . A method of altering melanin synthesis in a subject, comprising administering to the subject an amount of a nucleic acid that hybridizes to a nucleic acid encoding an agouti signaling protein, whereby the agouti encoding nucleic acid is not transcribed and melanin synthesis is altered.  
     
     
         40 . A method of treating a hyperpigmentary condition in a subject, comprising administering to the subject the agouti signaling protein or a biologically active peptide thereof.  
     
     
         41 . A method of screening for inhibitors of melanin synthesis, comprising: 
 a) contacting a melanocyte culture with an amount of a putative inhibitor of melanin synthesis;    b) determining the amount of melanocyte enzyme present in the melanocyte culture from step a);    c) comparing the amount of melanocyte enzyme determined in step    d) to the amount of melanocyte enzyme in an uncontacted melanocyte culture; and    e) correlating a decrease in at least one melanocyte enzyme with an inhibitor of melanin synthesis.