The role of mitochondria on the formation of lipid droplets in adipocytes:

Live cell imaging of mitochondria and lipid droplets

Abstract

　　White adipocytes have endocrine functions and secrete hormones and cytokines in response to various changes in their energy states. Mitochondria are the keystones of energy metabolism and they continuously join and divide, controlling the energy states of the cells. In contrast to the brown adipocytes, which is specialized for the non-shivering thermogenesis and in which the role of the mitochondria in cellular function has been intensively investigated, the role of mitochondria in the white adipocytes is virtually unknown. In this study, we observed 3T3-L1 adipocytes, the model of white adipocytes during differentiation by live cell imaging with fluorescent dyes focusing on the mitochondria and the lipid droplets. The shapes of mitochondria were clearly observed in the cells on 32 days after differentiation, although the lipid droplets were well-developed and the space for mitochondria was limited in the cells. At all differentiation stages, mitochondria appeared to be gathered around the lipid droplets, which suggests the existence of some functional relationships between the mitochondria and lipid droplets.