RANKL-mediated osteoclast formation from murine RAW 264.7 cells.

Extensive research efforts over the years have provided us with great insights into how bone-resorbing osteoclasts (OCs) develop and function and, based on such work, valuable antiresorptive therapies have been developed to help combat the excessive bone loss that occurs in numerous skeletal disorders. The RAW 264.7 murine cell line has proven to be an important tool for in vitro studies of OC formation and function, having particular advantages over the use of OCs generated from primary bone marrow cell populations or directly isolated from murine bones. These include their ready access and availability, simple culture for this pure macrophage/pre-OC population, sensitive and rapid development into highly bone-resorptive OCs expressing hallmark OC characteristics following their RANKL stimulation, abundance of RAW cell-derived OCs that can be generated to provide large amounts of study material, relative ease of transfection for genetic and regulatory manipulation, and close correlation in characteristics, gene expression, signaling, and developmental or functional processes between RAW cell-derived OCs and OCs either directly isolated from murine bones or formed in vitro from primary bone marrow precursor cells. Here, we describe methods for the culture and RANKL-mediated differentiation of RAW cells into bone-resorptive OCs as well as procedures for their enrichment, characterization, and general use in diverse analytical assays.