Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 10, 2021 - March 11, 2021
In has recently been pointed out that changes in the shape of cell nuclei including DNA may affect various cellular functions. Furthermore, the changes in the force on the nucleus associated with remodeling of the actin cytoskeleton has also been involved in osteogenic differentiation of cells. In such differentiation process of cells, the localization of actin filaments was changed and the shape of the nucleus was greatly changed. However, it has not been quantitatively clarified how actin filaments exert their internal force on the nucleus or how the structure of the nucleus changes during the process of osteogenic differentiation. To clarify these issues MC3T3-E1 osteoblast-like cells were cultured in osteoinductive medium to promote bone differentiation. An atomic force microscopy (AFM) was used to examine the mechanical properties of the nucleus in detail, and to estimate the internal tension of actin filaments. We found that the internal tension of actin filaments significantly increased with actin remodeling in the early stage of osteogenic differentiation, consequently generated the intracellular compressive forces to the nucleus. The forces also induced the nucleus remodeling with softening. Then the actin localization at cell periphery occurred in the latter term of osteogenic differentiation. The results indicate that such changes in the intracellular forces and structures may be important mechanical factors for osteogenic differentiation.
