Fibroblast function in psoriatic arthritis. II. Increased expression of beta platelet derived growth factor receptors and increased production of growth factor and cytokines.

OBJECTIVE

The main objective was to investigate the expression of platelet derived growth factor (PDGF) receptors, and production of growth factors and cytokines from psoriatic skin and synovium derived fibroblasts.

METHODS

Fibroblast cultures were established from normal and psoriatic skin and synovium. Confluent cultures of fibroblasts were used for a receptor binding assay for PDGF, and then extracts were run on Western blot. The amount of immunoreactive A and B chain peptides present was determined with specific A or B chain antisera. Production of interleukin 1 beta and PDGF-beta was accomplished by neutralization with the use of commercially available antisera. A functional assay was used to measure transforming growth factor-beta (TGF-beta).

RESULTS

There was an increased expression of the beta PDGF receptor in the psoriatic fibroblasts. Interleukin 1 beta and PDGF-beta production by psoriatic fibroblasts was also increased. However, TGF-beta production was similar in normal and psoriatic fibroblasts.

CONCLUSION

Our data demonstrate an increased expression of beta PDGF receptor, and production of IL-1 beta and PDGF by psoriatic fibroblasts. The findings provide further support for an active role of this cell line in the pathogenesis of psoriasis and psoriatic arthritis.