Cathepsin C-based screening methods for identifying modulators of pain

1. A method for identifying a compound that reduces pain comprising:

a. providing a test cell transfected with a nucleic acid vector comprising the promoter of a Cathepsin C gene operably linked to a reporter gene;

b. determining the reporter gene activity of the test cells in the presence of a test compound;

c. determining the reporter gene activity of the test cells in absence of the test compound; and

d. comparing the reporter gene activity of the test cells in the presence of the test compound to the reporter gene activity of the test cells in the absence of the test compound, wherein a decrease in activity of the reporter gene in the test cell in the presence of the test compound as compared to the activity of the reporter gene in the test cell in the absence of the test compound indicates that the test compound will reduce pain.

2. The method of claim 1 , wherein the reporter gene is selected from the group consisting of beta lactamase (LacZ), luciferase, green fluorescent protein (GFP), blue fluorescent protein (BFP), DsRed, HIS3, URA3, TRP1, LEU2, and beta galactosidase.

3. A method for identifying a compound that reduces pain comprising:

a. contacting a nucleic acid coding for a Cathepsin C protein with a test compound in a transcriptionally active system;

b. determining the amount of mRNA coding for the Cathepsin C protein that is present in the system in the presence of the test compound;

c. determining the amount of mRNA coding for the Cathepsin C protein that is present in the system in the absence of the test compound; and

d. comparing the amount of mRNA that is present in the system in the presence of the test compound to the amount of mRNA that is present in the system in the absence of the test compound, wherein decreased expression of mRNA in the presence of the test compound as compared to the expression level of mRNA in the absence of the test compound indicates that the test compound will reduce pain.

4. The method of claim 3 , wherein a cell expressing recombinant Cathepsin C is used.

5. The method of claim 4 , wherein Cathepsin C is encoded by a polynucleotide selected from the group consisting of:

a. a polynucleotide comprising the nucleic acid sequence of SEQ ID NO: 1,

and

b. a polynucleotide coding for the Cathepsin C protein of SEQ ID NO: 2.

6. A method for identifying a compound that reduces pain comprising:

a. providing a test cell transfected with a nucleic acid vector comprising the promoter of a Cathepsin C gene operably linked to a reporter gene;

b. providing a control cell transfected with a control vector comprising a reporter gene that is not operably linked to the promoter of a Cathepsin C gene;

c. determining the reporter gene activity of each of the cells in steps a) and b) in the presence of a test compound; and

d. comparing the reporter gene activity of the test cell in the presence of the test compound to the reporter gene activity of the control cell in the presence of the test compound, wherein decreased activity of the reporter gene in the test cell in the presence of the test compound as compared to the activity of the reporter gene in the control cell in the presence of the test compound indicates that the test compound will reduce pain.

7. The method of claim 6 , wherein the reporter gene is selected from the group consisting of beta lactamase (LacZ), luciferase, green fluorescent protein (GFP), blue fluorescent protein (BFP), DsRed, HIS3, URA3, TRP1, LEU2, and beta galactosidase.