Mild osteoarthritis biomarkers and uses thereof
The invention relates to the identification and selection of novel biomarkers and the identification and selection of novel biomarker combinations which are differentially expressed in individuals with mild osteoarthritis as compared with individuals without osteoarthritis. Polynucleotides and proteins which specifically and/or selectively hybridize to the products of the biomarkers of the invention are also encompassed within the scope of the invention as are kits containing said polynucleotides and proteins for use in diagnosing mild osteoarthritis. Further encompassed by the invention is the use of the polynucleotides and proteins which specifically and/or selectively hybridize to the product of the biomarkers of the invention to monitor disease regression in an individual and to monitor the efficacy of therapeutic regimens. The invention also provides for methods of using the products of the biomarkers of the invention in the identification of novel therapeutic targets for osteoarthritis.
1. A method of diagnosing mild osteoarthritis in a human test subject, said method comprising: detecting the level of IL13RA1 RNA in a blood sample from said test subject and diagnosing said test subject as having mild osteoarthritis when the level of said IL13RA1 RNA is decreased with a p value of less than 0.2 relative to the level of said IL13RA1 RNA in a reference sample, wherein said reference sample comprises blood obtained from human control subjects who are clinically diagnosed as not having osteoarthritis.
2. The method of claim 1 , wherein said detecting is effected using at least one oligonucleotide of predetermined sequence which is specific for said IL13RA1 RNA and/or for cDNA complementary to said IL13RA1 RNA.
3. The method of claim 1 , wherein said detecting is effected using nucleic acid amplification.
4. The method of claim 3 , wherein said nucleic acid amplification comprises quantitative PCR.
5. The method of claim 3 , wherein said nucleic acid amplification is effected using primers which can hybridize specifically to said IL13RA1 RNA and/or to cDNA complementary to said IL13RA1 RNA.
6. The method of claim 3 , wherein said nucleic acid amplification is effected using primers 15-25 nucleotides in length.
7. The method of claim 3 , wherein said nucleic acid amplification is effected using at least one primer which includes a nucleic acid sequence identified as SEQ ID NO: 166.
8. The method of claim 3 , wherein said detecting is effected using at least one probe which includes a nucleic acid sequence, or an antisense sequence of said nucleic acid sequence, identified as SEQ ID NO: 168.
9. The method of claim 1 , wherein said detecting is effected using an immobilized nucleic acid probe which can hybridize specifically to said IL13RA1 RNA and/or to cDNA complementary to said IL13RA1 RNA.
10. The method of claim 9 , wherein said probe is a molecule selected from the group consisting of a RNA, a DNA, a cDNA, a PCR product and an EST.
11. The method of claim 1 , wherein said detecting comprises:
(i) isolating RNA from said blood sample, thereby obtaining a sample of isolated RNA, and
(ii) quantifying a level of said IL13RA1 RNA in said sample of isolated RNA.
12. The method of claim 1 , wherein said blood sample is selected from the group consisting of a whole blood sample, a blood sample which has not been fractionated into cell types, and a sample of blood that has been lysed.
13. The method of claim 1 , wherein said sample is a drop of whole blood.
14. The method of claim 1 , wherein said test subject is suspected of having osteoarthritis.
15. The method of claim 1 further comprising quantifying the level of said IL13RA1 RNA in said reference sample, thereby providing the level of said IL13RA1 RNA in said reference sample.
16. The method of claim 1 , wherein said test subject is diagnosed as having mild osteoarthritis when the level of said IL13RA1 RNA in said blood sample from said test subject is decreased by 0.6 fold relative to the level of said ILl 3RA 1 RNA in said reference sample.