Evaluation of SV40-transformed synovial fibroblasts in the study of rheumatoid arthritis pathogenesis

The SV40 T antigen has been used to generate immortalized cells from rheumatoid arthritis (RA) synovial fibroblasts (RASFs) that are commonly used in lieu of primary RASFs. In the current study, we investigated the effect of stimulation by tissue necrosis factor alpha (TNF-α) and interleukin 17 (IL-17) on primary and immortalized RASFs in order to gauge the appropriateness of the use of immortalized RASFs, the MH7A cell line, in the study of RA pathogenesis. Changes in the levels of secretion and expression of 8 proteins associated with RA upon stimulation were assessed by multiplex immunoassay. IL-17 stimulation had a minimal impact on protein secretion and expression for primary and immortalized cells. Basic fibroblast growth factor (FGF-2) was not detectable for the primary cells but was detectable for the immortalized cells. In contrast, monocyte chemoattractant protein 1 (MCP-1) was detectable for primary cells but was undetectable for immortalized cells. In general, protein expression and secretion by cells stimulated with TNF-α were significantly increased. For primary cells, several proteins were below the limit of detection for unstimulated cells and cells stimulated with IL-17, while levels for TNF-α-stimulated cells were within the detectable range. For the same proteins, expression was observed for immortalized cells, regardless of stimulation, suggestive of constitutive activation of the NF-κB signaling pathway. The current study therefore provides strong evidence that immortalized and primary RASFs differ in regard to protein expression and secretion and therefore may not be appropriate for use in the study of RA pathogenesis.