Osteoclasts are multinucleated cells from hematopoietic origin, which resorb bone at certain locations in a highly regulated and coordinated manner. This allows bone to preserve its flexibility and integrity throughout the different loads it encounters. During osteoclast adhesion to bone surface, specialized actin based structures, termed the sealing zone rings, are formed at the cell-bone interface and delimit the resorptive lacuna. Observed differences between the formation and dynamics of these sealing zone structures in osteoclasts seeded on artificial or physiological surfaces suggest surface dependency. However, the effect of different bone surface parameters on the sealing zone rings is still not well understood, despite the importance of osteoclast adhesion to its resorption functionality. In order to gain insights regarding the relation between bone physical parameters to the dynamic behavior of sealing zone rings in active osteoclasts, we have developed a specialized correlative method; the cortical bone surfaces are imaged by a scanning electron microscope and atomic force microscope and overlaid with dynamic tracking of sealing zone structures in live osteoclasts, taken with the deltavision optical microscope. Using this approach, we show preferential formation of rings around bone surface protrusion of limited size, as oppose to possible other physiologically relevant structures, such as microcracks. In addition, we show that resorption functionality relates to larger sealing zone rings that adapt pit morphology. We suggest that this correlative method can be used for a wide variety of applications, which involve cell adhesion to non-transparent surfaces that may be sensitive to standard electron microscopy preparation methods.
See also: Shemesh, Michal, et al. "Study of Osteoclast Adhesion to Cortical Bone Surfaces: A Correlative Microscopy Approach for Concomitant Imaging of Cellular Dynamics and Surface Modifications." ACS applied materials & interfaces (2015).
