OPG Human

Osteoprotegerin is a secreted protein that functions as a decoy receptor for the receptor activator of nuclear factor kappa-B ligand (RANKL). By binding to RANKL, OPG prevents it from interacting with its receptor, RANK, on the surface of osteoclasts and their precursors. This interaction inhibits osteoclast differentiation and activation, thereby reducing bone resorption and maintaining bone density .

Recombinant human OPG is typically produced using mammalian cell lines, such as the mouse myeloma cell line NS0. The protein is expressed and then purified to achieve high purity levels, often exceeding 95%, as determined by SDS-PAGE and other analytical techniques . The recombinant form is available in both carrier-free and carrier-containing formulations, with the latter often including bovine serum albumin (BSA) to enhance protein stability .

The biological activity of recombinant human OPG is measured by its ability to inhibit TRAIL-mediated cytotoxicity in specific cell lines, such as L-929 mouse fibroblast cells. The effective dose (ED50) for this activity typically ranges from 8 to 24 ng/mL . This activity underscores OPG’s role in modulating cell survival and apoptosis, which is critical in various physiological and pathological contexts.

Osteoprotegerin has been extensively studied for its role in bone diseases, such as osteoporosis and Paget’s disease. By inhibiting osteoclast activity, OPG helps in reducing bone loss and improving bone density. Additionally, OPG’s involvement in cancer biology has garnered significant attention. It has been shown to influence tumor growth, metastasis, and angiogenesis, making it a potential therapeutic target in oncology .

Recombinant human OPG is typically lyophilized and stored at temperatures ranging from -20°C to -70°C to maintain its stability. Upon reconstitution, it should be stored under sterile conditions and used within a specified timeframe to ensure its biological activity .