Mechanobiology of osteoclast

Mechanical stimulation is vital for bone tissue growth and development, and different types and intensities of mechanical stress constantly adjust metabolic homeostasis of bone. Osteoclasts (OCs) are mechanosensitive cells. Different mechanical stimulations have been verified to play crucial roles in osteoclastogenesis and the resorption of bone via various experiments. The cell morphology and marker gene expression of OCs are modulated by fluid shear stress (FSS), which influences OC differentiation without impacting cell viability. Growing evidence demonstrates that the differentiation and function of OCs can be influenced in different ways by mechanical vibration. Mechanical tensile stress significantly affects OC formation, apoptosis, and bone resorption activities in a manner that depends on the stress magnitude, mechanical tensile strengths, and duration. Compressive force promotes OC formation and bone resorption. Studies of modeled microgravity systems have also provided evidence that mechanical unloading increases osteoclastogenesis and bone resorption. The response of OCs to different mechanical stimuli is mediated by cytoskeletal elements, membrane integrins, intracellular adhesion molecules, and membrane and nuclear mechanosensors, triggering multiple signaling pathways and altering downstream gene expression, further contributing to changes in OC formation, cell morphology, viability, and differentiation status. Here, we summarize the effects and mechanisms of mechanobiology on OC formation, differentiation, and physiological functions to provide new insight into mechanobiology research.