Identification of genes modulated in rheumatoid arthritis using complementary DNA microarray analysis of lymphoblastoid B cell lines from disease-discordant monozygotic twins.
OBJECTIVE
To identify disease-specific gene expression profiles in patients with rheumatoid arthritis (RA), using complementary DNA (cDNA) microarray analyses on lymphoblastoid B cell lines (LCLs) derived from RA-discordant monozygotic (MZ) twins.


METHODS
The cDNA was prepared from LCLs derived from the peripheral blood of 11 pairs of RA-discordant MZ twins. The RA twin cDNA was labeled with cy5 fluorescent dye, and the cDNA of the healthy co-twin was labeled with cy3. To determine relative expression profiles, cDNA from each twin pair was combined and hybridized on 20,000-element microarray chips. Immunohistochemistry and real-time polymerase chain reaction were used to detect the expression of selected gene products in synovial tissue from patients with RA compared with patients with osteoarthritis and normal healthy controls.


RESULTS
In RA twin LCLs compared with healthy co-twin LCLs, 1,163 transcripts were significantly differentially expressed. Of these, 747 were overexpressed and 416 were underexpressed. Gene ontology analysis revealed many genes known to play a role in apoptosis, angiogenesis, proteolysis, and signaling. The 3 most significantly overexpressed genes were laeverin (a novel enzyme with sequence homology to CD13), 11beta-hydroxysteroid dehydrogenase type 2 (a steroid pathway enzyme), and cysteine-rich, angiogenic inducer 61 (a known angiogenic factor). The products of these genes, heretofore uncharacterized in RA, were all abundantly expressed in RA synovial tissues.


CONCLUSIONS
Microarray cDNA analysis of peripheral blood-derived LCLs from well-controlled patient populations is a useful tool to detect RA-relevant genes and could help in identifying novel therapeutic targets.
Haas
Christian S
CS
University of Michigan Center, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0680, USA.
Creighton
Chad J
CJ
Pi
Xiujun
X
Maine
Ira
I
Koch
Alisa E
AE
Haines
G Kenneth
GK
Ling
Song
S
Chinnaiyan
Arul M
AM
Holoshitz
Joseph
J
D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000235:genetics / Q000378:metabolism; D042501:Angiogenic Proteins / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics; D001172:Arthritis, Rheumatoid / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D001402:B-Lymphocytes / Q000378:metabolism / Q000473:pathology*; D002460:Cell Line; D055515:Cysteine-Rich Protein 61; D018076:DNA, Complementary / Q000235:genetics; D004200:Diseases in Twins / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010003:Osteoarthritis; D013583:Synovial Membrane / Q000378:metabolism; D014430:Twins, Monozygotic / Q000235:genetics*
D042501:Angiogenic Proteins; C501848:CCN1 protein, human; D055515:Cysteine-Rich Protein 61; D018076:DNA, Complementary; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; C482089:LVRN protein, human; D045726:Metalloproteases