Extracellular Matrix Protection Factor-1, a Novel Human Osteoarthritis Therapeutic, Decreases the Expression of Interleukin-1 Beta by Primary Cultures of Human Osteoarthritic Chondrocytes

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 2.5x10 ⁶ 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.