Osteoarthritis (OA) is characterized by an imbalance of cartilage extracellular matrix (ECM) production and degradation due, in part, to increased cytokine production. The cytokine Interleukin-1 beta (IL-1β) is produced by OA articular chondrocytes and plays a prominent role in altering ECM metabolism by targeting the matrix metalloproteinases (MMPs) that degrade ECM. We are developing a novel, OA therapeutic, Extracellular Matrix Protection Factor-1 (ECPF-1) that targets MMP interaction with its ECM substrate. We have demonstrated a reduction in ECM degradation when primary, human OA chondrocyte (HOAC) cultures are treated with ECPF-1. In this study, HOACs isolated from total knee arthroplasty were reared in three-dimensional, serum free, alginate cultures. Least and greatest pathology (LP & GP) of femoral condyles and tibial plateaus were determined by gross inspection and cells were cultured separately. Chondrocytes were plated 2.5x106 cells per milliliter alginate and incubated five days in serum-free medium. Cells were released from the alginate and the RNA extracted from the pellet, reverse transcribed into cDNA and quantitative, real time PCR (qRT-PCR) was performed by TaqMan Gene Expression assays for IL-1β and 18s rRNA. IL-1β expression was detectable in mRNA produced by LP and GP HOAC cultures. Expression was reduced 2-fold in LP cultures treated 24 hours with 2.5uM ECPF-1 and 1.4 fold in GP cultures. The results demonstrate the ability of ECPF-1 to alter expression of a molecule involved in the feedback loop of ECM destruction. ECPF-1 provides a tool with which to further define the cellular mechanisms responsible for OA chondrocyte pathology.
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