Abstract
Objective
To investigate whether retroviral gene transfer of ribozymes targeting matrix metalloproteinase 1 (MMP‐1) inhibits the production of MMP‐1 in rheumatoid arthritis synovial fibroblasts (RASFs) and reduces the invasiveness of these cells in vivo.
Methods
MMP‐1–specific ribozymes (RzMMP‐1) were designed and cloned into the pLNSX retroviral vector. Cleavage of MMP‐1 was determined in vitro, and the most effective ribozyme was selected for further investigation. RASFs were transduced with replication‐deficient viruses carrying RzMMP‐1 or with empty viruses (mock). Quantitative polymerase chain reaction with cleavage site–spanning fluorescent probes was used to measure the levels of MMP‐1, MMP‐9, and MMP‐13 messenger RNA. In addition, protein levels of MMP‐1 in cell culture supernatants were determined by enzyme linked immunosorbent assay. The effects of stimulation with lipopolysaccharide (LPS) and tumor necrosis factor α (TNFα) on the production of MMP‐1 were assessed accordingly. The invasiveness of RzMMP‐1–transduced, mock‐transduced, and untransduced RASFs was analyzed in the SCID mouse in vivo model of RA.
Results
Transduction of RASFs with RzMMP‐1 significantly decreased the production of MMP‐1 in RASFs without affecting other MMPs, such as MMP‐9 and MMP‐13. RzMMP‐1 not only reduced the spontaneous production of MMP‐1, but also prevented the LPS‐ and TNFα‐induced increase in MMP‐1 production. Inhibition of MMP‐1 was maintained for at least 2 months and was accompanied by a significant reduction of the invasiveness of RASFs in the SCID mouse model of RA.
Conclusion
Intracellular expression of ribozymes constitutes a feasible tool for inhibiting the production of matrix‐degrading enzymes. Inhibition of MMP‐1 alone results in a significant reduction of cartilage invasion by RASFs.