Connective tissue growth factor promotes articular damage by increased osteoclastogenesis in patients with rheumatoid arthritis.
BACKGROUND
A protein analysis using a mass spectrometry indicated that there are serum proteins showing significant quantitative changes after the administration of infliximab. Among them, connective tissue growth factor (CTGF) seems to be related to the pathogenesis of rheumatoid arthritis (RA). Therefore, this study was conducted to investigate how CTGF is associated with the disease progression of RA.


METHODS
Serum samples were collected from RA patients in active or inactive disease stages, and before or after treatments with infliximab. CTGF production was evaluated by ELISA, RT-PCR, indirect immunofluorescence microscopy, and immunoblotting. Osteoclastogenesis was evaluated using tartrate-resistant acid phosphatase (TRAP) staining, a bone resorption assay and osteoclasts specific catalytic enzymes productions.


RESULTS
The serum concentrations of CTGF in RA were greater than in normal healthy controls and disease controls. Interestingly, those were significantly higher in active RA patients compared to inactive RA patients. Furthermore, the CTGF levels significantly were decreased by infliximab concomitant with the disease amelioration. In addition, tumour necrosis factor (TNF)alpha can induce the CTGF production from synovial fibroblasts even though TNFalpha can oppositely inhibit the production of CTGF from chondrocytes. CTGF promoted the induction of the quantitative and qualitative activities of osteoclasts in combination with M-CSF and receptor activator of NF-kappaB ligand (RANKL). In addition, we newly found integrin alphaVbeta3 on the osteoclasts as a CTGF receptor.


CONCLUSIONS
These results indicate that aberrant CTGF production induced by TNFalpha plays a central role for the abnormal osteoclastic activation in RA patients. Restoration of aberrant CTGF production may contribute to the inhibition of articular destruction in infliximab treatment.
Nozawa
Kazuhisa
K
Institute for Environment and Gender Specific Medicine, Juntendo University Graduate School of Medicine, Chiba, 2-1-1 Tomioka, Urayasu, Chiba, 279-0021, Japan. kazunozawa@aol.com
Fujishiro
Maki
M
Kawasaki
Mikiko
M
Kaneko
Hiroshi
H
Iwabuchi
Kazuhisa
K
Yanagida
Mitsuaki
M
Suzuki
Fujihiko
F
Miyazawa
Keiji
K
Takasaki
Yoshinari
Y
Ogawa
Hideoki
H
Takamori
Kenji
K
Sekigawa
Iwao
I
D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology; D055513:Connective Tissue Growth Factor / Q000378:metabolism*; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D000069285:Infliximab; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha; D055513:Connective Tissue Growth Factor; D000069285:Infliximab