Speaker
Description
In addition to biochemical factors, physical factors of the cellular microenvironment have been widely recognized as important in determining cell behaviors. For example, substrate stiffness increases cell spread area, proliferation, and osteogenic differentiation in 2D cell culture. In contrast, cells may exhibit different responses to substrate stiffness in three-dimensional (3D) cell cultures. This difference underscores a knowledge gap in mechanobiology. Our lab is addressing this gap by culturing cells in spherical microwells of diameters comparable to cell sizes as a 3D cell culture and studying how spherical microwells affect cellular behaviors. We used human mesenchymal stem cells (hMSCs) as our model. Our preliminary data demonstrated that our spherical microwells caused cell cycle arrest in the G1 phase. We observed that cells exhibited very different F-actin and paxillin distributions in spherical microwells (60-μm in diameter) from cells in a 2D culture, and cells showed wrinkled Lamin A/C, a high standard deviation in DAPI intensity, fewer nucleoli, and a reduction in the volumes of both the nucleus and nucleolus of cells in spherical microwells. These results highlighted the profound effects of microwell on cells. To gain deeper insights into the effects on cell function, we conducted RNA sequencing (RNA-seq) to explore gene expression and evaluated cell differentiation. We found that spherical microwells promoted both adipocyte and osteocyte differentiation. Taken together, spherical microwells reshaped hMSC morphologies, arrested cell cycle, and enhanced differentiation. These changes may be related to the altered chromatin structures.
Keywords: spherical microwell, cell cycle, nuclear morphology, cell differentiation, chromatin structure
