Effects of oriented substrates on cell morphology, the cell cycle, and the cytoskeleton in Ros 17/2.8 cells

Abstract

Absence of gravity or microgravity influences the cellular functions of bone forming osteoblasts. The underlying mechanism, however, of cellular sensing and responding to the gravity vector is poorly understood. This work quantified the impact of vector-directional gravity on the biological responses of Ros 17/2.8 cells grown on upward-, downward-or edge-on-oriented substrates. Cell morphology and nuclear translocation, cell proliferation and the cell cycle, and cytoskeletal reorganization were found to vary significantly in the three orientations. All of the responses were duration-dependent. These results provide a new insight into understanding how osteoblasts respond to static vector-directional gravity.substrate orientation, osteoblasts, cell shape, cell cycle, cytoskeleton Citation:Li H, Chen J, Zhang Y, et al. Effects of oriented substrates on cell morphology, the cell cycle, and the cytoskeleton in Ros 17/2.8 cells.

Mechanical remodeling of normally sized mammalian cells under a gravity vector

“…S6), as ROCK is placed at the hub of the complex signaling network that controls actomyosin contractility and stress fiber assembly (41). Noting that the specialized structures of actin stress fiber and vimentin cord are also visualized for Ros 17/2.8 cells placed in the 3 orientations at 120 h (5), these results imply the universality of these structures for biodiverse cell models.…”

“…For cells grown on the 90° coverslip, 100 ml medium was added, which resulted in a maximum hydrostatic pressure difference of 12 mmH2Obetween the cells at the bottom and the top of the coverslip. The impact of such pressure difference on cells was negligible (5).…”

“…Inversion of culture substrate cannot alter the number and function of attached osteoblasts, even though an immediate response‐diminished viable osteoblast number‐is observed in sparse, early cultures (4). Cell area, nucleus translocation, cell cycle, and F‐actin reorganization vary significantly in a duration‐dependent manner when Ros 17/2.8 cells make up a monolayer and are spread on downward‐or edge‐on‐orientated substrate compared with those on an upward orientation (5). More quantitative analysis is observed in large‐sized Xenopus oocytes (∼1 mm), where the nucleolus sedimentation is dominant compared with the thermal fluctuation at gravity potential > thermal energy scale (6), which implies that the sedimentation of a relatively dense nucleus could initiate gravisensing in a mammalian cell.…”

“…Here, we hypothesized that the biological homeostasis of a mammalian cell on a gravity vector is maintained by the mechanical balance of nucleus sedimentation with cytoskeletal remodeling and FAC rearrangement on long timescales. By using an orientation‐varied cell culture assay, previously described (3–5), we conducted detailed analyses for adherent MC3T3‐E1 cells to unravel how a gravity vector governs mechanical stability, mainly from the viewpoints of nucleus sedimentation, cytoskeletal remodeling, and FAC rearrangement. Our results suggest that those gravisensing mechanisms in plant cells could be applicable to mammalian cells in a distinct way.…”

Mechano-biological Coupling of Cellular Responses to Microgravity

“…Meanwhile, a virtual numerical platform upon computational fluid dynamics needs to be developed for evaluating the effect of SM on ground, optimizing the mechanical parameters for the clinostat or rotary bioreactor, and designing the novel bioreactors for mimicking the biological responses under microgravity. Moreover, a conceptual test on gravity-vector directed effects also indicate that downward-or edge-on-orientated substrate enhances the F-actin expression with shrinking morphology of rat osteosarcoma Ros 17/2.8 cells (Li et al 2010). Such the conceptual clarification helps to elucidate the basic processes in space life science and biotechnology as well as in space physiology and medicine, and to present the scientific merits of related ground-based studies.…”