Figure 1

Expression of junctional adhesion molecule-C (JAM-C) in human arthritic synovium. Expression of JAM-C was examined by immunohistochemistry in human osteoarthritis (OA) (a) and rheumatoid arthritis (RA) (b) synovial tissue. The panels labeled 1 show the original magnification (× 100). The panels labeled 2 show expression of JAM-C in the synovial lining layer (magnification × 400), and panels labeled 3 show JAM-C associated with blood vessels in the sublining (magnification × 400). The panels labeled 4 show negative control sections incubated with preimmune serum. Scale bars = 60 μm (panels 1 and 4) and 15 μm (panels 2 and 3). (c) Quantification of JAM-C expression in OA and RA synovial tissues. JAM-C immunohistochemical synovial tissue sections from four different OA and RA patients were scanned, and the surface of immunoreactive areas was determined and expressed as the percentage of the surface of the image examined. Results are expressed as the mean ± standard error of the mean. *p < 0.001 OA versus RA as assessed using the Wilcoxon rank sum test. (d) Reverse transcriptase-polymerase chain reaction (PCR) analysis of JAM-C mRNA expression in human synovial tissue samples and in cultured human synovial fibroblasts. A representative agarose gel electrophoresis of PCR products is shown. bp, base pairs; H₂O, polymerase chain reaction negative control; hSF1 and hSF2, human rheumatoid arthritis synovial fibroblast cultures from two different patients used after the third passage; OA, osteoarthritis synovial tissue; RA, rheumatoid arthritis synovial tissue; RT neg, non-reverse-transcribed sample.