Novel method of murine embryonic stem cell-derived osteoclast development.

Murine embryonic stem (mES) cells are self-renewing pluripotent cells that bear the capacity to differentiate into ectoderm-, endoderm-, and mesoderm-derived tissues. In suspension culture, embryonic stem (ES) cells grow into spherical embryoid bodies (EBs) and are useful for the study of specific gene products in the development and function of various tissue types. Osteoclasts are hematopoietic stem cell-derived cells that participate in bone turnover by secreting resorptive molecules such as hydrochloric acid and acidic proteases, which degrade the bone extracellular matrix. Aberrant osteoclast function leads to dysplastic, erosive, and sclerosing bone diseases. Previous studies have reported the derivation of osteoclasts from mES cells; however, most of these protocols require coculture with stromal cell lines. We describe two simplified, novel methods of stromal cell-independent ES cell-derived osteoclast development.