Reorganization of actin filaments enhances chondrogenic differentiation of cells derived from murine embryonic stem cells.

Differentiation of embryonic stem cells is of great interest to developmental biology and regenerative medicine. This study investigated the effects of cytochalasin D (CD) on the distribution of actin filaments in mouse embryoid body (EB)-derived cells. Furthermore, CD was applied to chondrogenic medium to examine its chondrogenic effect. CD at a concentration of 1 microg/ml disrupted stress fibers in EB-derived cells. Actin filaments in treated cells reorganized into a peripheral pattern, and type II collagen was detected by immunocytochemistry. The expression of type II collagen, Sox9, and at a later time point, aggrecan was up-regulated after CD treatment. In the CD-treated cells, Oct4 and Sox2, representing undifferentiation, were down-regulated as well as Sox1, AFP, and CTN-1, representing ectoderm, endoderm, and cardiogenesis, respectively. In conclusion, CD treatment enhances chondrogenesis of EB-derived cells. Moreover, it promotes a more complete stem cell differentiation toward chondrogenesis, when cultured in chondrogenic medium.