Methods of diagnosing and treating fibrosis

Abstract

The present invention is directed to methods of diagnosing and treating a fibrotic condition in a mammalian subject. These methods involve measuring the levels of trimethylation at lysine residue 27 of histone-3 and/or measuring the expression levels of EZH2 or YY-1. Agents useful for treating fibrosis or a fibrotic condition are also disclosed.

What is claimed: 
     
         1 . A method of diagnosing a fibrotic condition in a subject, said method comprising:
 measuring the level of trimethylation at lysine residue 27 of histone-3 (“H3K27”) in a biological sample from the subject;   comparing the level of H3K27 trimethylation in the biological sample to a standard level of H3K27 trimethylation; and   diagnosing the presence or absence of a fibrotic condition based on said comparing.   
     
     
         2 . The method according to  claim 1 , wherein the standard level of H3K27 trimethylation comprises an average level of trimethylation at lysine residue 27 of histone-3 in a non-fibrotic sample, and a higher level of H3K27 trimethylation in the biological sample from the subject compared to the standard level of H3K27 trimethylation indicates the presence of a fibrotic condition in the subject. 
     
     
         3 . The method according to  claim 1 , wherein the standard level of H3K27 trimethylation comprises an average level of trimethylation at lysine residue 27 of histone-3 in a fibrotic sample, and a lower level of H3K27 trimethylation in the biological sample from the subject compared to the standard level of H3K27 trimethylation indicates the absence of a fibrotic condition in the subject. 
     
     
         4 . The method according to  claim 1 , wherein the fibrotic condition is pulmonary fibrosis, cardiac fibrosis, kidney fibrosis, liver fibrosis, neurofibrosis, or skin fibrosis. 
     
     
         5 . The method according to  claim 1 , wherein said measuring comprises:
 detecting H3K27 trimethylation using an immunodetection assay with a binding molecule that recognizes and binds to a trimethylated lysine 27 residue of histone-3.   
     
     
         6 . A method of diagnosing a fibrotic condition in a subject, said method comprising:
 measuring the expression level of Enhancer of Zeste Homolog 2 (“EZH2”) or Yin-Yang-1 (“YY-1”) in a biological sample from the subject;   comparing the expression level of EZH2 or YY-1 in the biological sample from the subject to a standard expression level of EZH2 or YY-1; and   diagnosing the presence of absence of a fibrotic condition based on said comparing.   
     
     
         7 . The method according to  claim 6 , wherein the standard expression level of EZH2 or YY-1 comprises an average expression level of EZH2 or YY-1 in a non-fibrotic sample, and a higher expression level of EZH2 or YY-1 in the biological sample from the subject compared to the standard expression level indicates the presence of a fibrotic condition in the subject. 
     
     
         8 . The method according to  claim 6 , wherein the standard expression level of EZH2 or YY-1 comprises an average expression level of EZH2 or YY-1 in a fibrotic sample, and a lower expression level of EZH2 or YY-1 in the biological sample from the subject compared to the standard expression level indicates the presence of fibrosis a fibrotic condition in the subject. 
     
     
         9 . The method according to  claim 6 , wherein the fibrotic condition is pulmonary fibrosis, cardiac fibrosis, kidney fibrosis, liver fibrosis, or skin fibrosis. 
     
     
         10 . The method according to  claim 6 , wherein said measuring comprises:
 measuring the RNA expression level of EZH2 or YY-1.   
     
     
         11 . The method according to  claim 10 , wherein the RNA expression level is measured using a nucleic acid hybridization assay or a nucleic acid amplification assay. 
     
     
         12 . The method according to  claim 6 , wherein said measuring comprises:
 measuring the protein expression level of EZH2 or YY-1.   
     
     
         13 . The method according to  claim 12 , wherein the protein expression level is measured using an immunodetection assay. 
     
     
         14 . A method of treating a subject having a fibrotic condition, said method comprising:
 selecting a subject having a fibrotic condition and   administering to the selected subject an agent that inhibits or reduces trimethylation at lysine residue 27 of histone-3 under conditions effective to treat a fibrotic condition in the subject.   
     
     
         15 . The method according to  claim 14 , wherein said fibrotic condition is pulmonary fibrosis, cardiac fibrosis, kidney fibrosis, liver fibrosis, neurofibrosis, or skin fibrosis. 
     
     
         16 . The method according to  claim 14 , wherein the agent is a histone lysine demethylase. 
     
     
         17 . The method according to  claim 14 , wherein the agent is a YY-I inhibitor. 
     
     
         18 . A method of identifying an agent that is effective for treating fibrosis, said method comprising:
 obtaining a first biological sample from an in vivo or in vitro experimental model of fibrosis;   administering a candidate agent to the experimental model;   obtaining a second biological sample from the experimental model after said administering;   measuring the level of trimethylation at lysine residue 27 of histone-3 (“H3K27”) in the first and second biological samples; and   comparing the level of H3K27 trimethylation in the first and second biological samples, wherein a decrease in the level of H3K27 trimethylation in the second biological sample relative to the level of H3K27 trimethylation in the first biological sample indicates that the agent is effective for treating fibrosis.   
     
     
         19 . The method according to  claim 18 , wherein the fibrosis is pulmonary fibrosis, cardiac fibrosis, kidney fibrosis, liver fibrosis, neurofibrosis, or skin fibrosis