Fig. 4

Emerging mysteries in the osteoclast biology. Single-cell studies have provoked new questions in the osteoclast biology field. Osteoclast precursors may comprise different subsets depending on life stages and pathologies; however, functional difference among osteoclasts derived from distinct precursors remains unclear. Given that osteoclast precursors can fuse one another to differentiate into osteoclasts, it will be important to elucidate the regulatory mechanisms of the multinuclear system to understand the functional diversity of osteoclasts. Although osteoclasts are thought to die quickly by apoptosis after resorbing bone, novel hypotheses regarding the fate of osteoclasts have emerged. Further studies are needed to draw a comprehensive picture of osteoclast life cycle and its functional diversity in health and disease