The Indication of C-MYC Transcripts in the Heterogenic Formation of Cell Types within the Synovial Membrane from Patients with Rheumatoid Arthritis

Journal/Book: Z Rheumatol 1998; 57 Suppl. 1: 50 (P 23). 1998;

Abstract: Institute of Pathology University of Leipzig Aims: In a early study we found the same expression of c-myc mRNA in samples of RA patients like in synovial membranes without pathological features (nSM). This abnormal finding to the presented data lead up to the question wich cell type is responsible for the differential expression of c-myc mRNA in RA synovial membranes (RA-SM). We investigated the expression of c-myc mRNA by in-situ hybridisation in 10 cryosections of RA-SM and in 5 sections without histological findings (nSM). Methods: In the in-situ hybridisation we used riboprobes obtained by self construction. Transcription template was obtained by cloning a PCR amplified fragment of human c-myc cDNA (corresponding to mRNA [HSMYC1] from EMBL-bank pos. 255 to 523 bases). The specific binding of antisense probe was testing on a Northern blot with total RNA from a human fibroblasts culture. Finally we carried out a immunhistochemical evidence with the mAK (AS 02) against fibroblasts around the modify c-myc mRNA expression in a double staining to sort out of a one cell population. Results: We were able to show distinct signals of c-myc mRNA in synovial tissues from RA-patients. Furthermore the number of c-myc mRNA signals was lower in nSM. A double staining was shown after the in-situ hybridisation with the mAK (AS 02) against fibroblasts. Such a marking with the mAK (CD68) against macrophages was up to now not detectable. Conclusion: These data suggest that the cell typ of fibroblasts is responsible for the changed transcript expression of c-myc in RA-synovial membrane. The different expression of c-myc protooncogene seems to have a relation to the proliferation of synovial membrane (synovial hyperplasia) in the pathogenesis of rheumatoid arthritis (RA). le

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