Analysis of cartilage oligomeric matrix protein (COMP) in synovial fibroblasts and synovial fluids |
| |
Authors: | Hummel KM; Neidhart M; Vilim V; Hauser N; Aicher WK; Gay RE; Gay S; Hauselmann HJ |
| |
Institution: | Center for Experimental Rheumatology, University Hospital, Zurich, Switzerland. |
| |
Abstract: | We investigated the expression of cartilage oligomeric matrix protein
(COMP) in normal and rheumatoid arthritis (RA) synovial fibroblasts. In
situ hybridization (ISH) was conducted on synovial specimens from five RA
patients applying specific probes for COMP or fibroblast collagen type I.
ISH was combined with immunohistochemistry, applying antibodies to the
macrophage marker CD68. Ribonuclease protection assay (RPA) and rapid
amplification of 3'-cDNA ends (3'-RACE) were performed on total RNA from
normal and RA synovial fibroblast cultures. Protein extracts from
fibroblasts and culture supernatants were compared with synovial fluids and
protein extracts from isolated chondrocytes by Western blot utilizing
polyclonal and monoclonal antibodies (18-G3 mAb) to COMP. COMP mRNA was
detected in fibroblasts of RA synovium by ISH, and in normal and RA
synovial fibroblast cultures by RPA. 3'-RACE demonstrated sequence homology
of chondrocyte and synovial fibroblast COMP along the coding sequence. COMP
protein was detected in synovial fibroblasts and culture supernatants by
immunoblot. Using polyclonal antibodies, the major portion of COMP from
fibroblasts and culture supernatants was present as low-molecular-weight
(LMW) bands, corresponding to those found in synovial fluids. These LMW
COMP bands, however, were not detected in any of the cells or tissues
tested using 18-G3 mAb. In protein extracts from chondrocytes and in COMP
purified from cartilage, these LMW bands could not be detected. In
conclusion, the data suggest that certain forms of COMP detected in
synovial fluid are secreted from synovial fibroblasts and could be
distinguished by specific mAbs from COMP secreted by chondrocytes.
|
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|