Spreading area and shape regulate apoptosis and differentiation of osteoblasts

Abstract

The in vivo observations have indicated that at the remodeling sites of bone, the spreading area or shape of preosteoblasts is confined by the mineralized matrix. But it remains unknown whether this spreading confinement regulates the differentiation or apoptosis of osteoblasts. In the present study, osteoblast-like cells (MC3T3-E1) were seeded on micropatterned islands with different area and shape. The expression of three osteogenic differentiation markers was measured by immunofluorescence staining and apoptotic cells were detected using a terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labelling assay kit. The membrane fluorescence staining results showed that the actual spreading area of micropatterned osteoblasts coincided with the designed value. When the area of a micropatterned cell was confined as 314 or 615 µm(2), which was lower than that of freely spreading osteoblasts, the circular shape promoted the expression of osteogenic differentiation markers and the percentage of apoptotic osteoblasts compared with the branched shape. This shape-regulated differentiation and apoptosis of osteoblasts with confined spreading area were abolished when actin polymerization was inhibited by cytochalasin D. The present study gives an insight into the roles of spreading morphology on osteoblastic differentiation and apoptosis.

Barium titanate nanoparticles and hypergravity stimulation improve differentiation of mesenchymal stem cells into osteoblasts

“…Overall, the characterization of cell shape and morphology showed that an increment of gravitational force, both in the presence or not of BTNPs, provided as a consequence a more irregular and spread morphology. This effect, consistent with other results available in the literature, 34 could contribute to the maturation toward osteoblasts, given that spread cells are committed to osteogenesis, and conversely, a rounded shape promotes adipogenesis. 35 Furthermore, the F-actin organization in parallel and welldefined stress fibers qualitatively observed after hypergravity stimulation is a further hint of cytoskeleton-tension enhancement, and consequently of the mechanotransduction leading to osteogenesis (mediated by RHOA and RUNX2).…”

Enhanced osteogenic differentiation of MC3T3‐E1 cells on grid‐topographic surface and evidence for involvement of YAP mediator

“…40 Spreading area and shape could regulate differentiation of osteoblasts. 41 The expression levels of key osteogenic markers cultured on GT and flat surfaces, including AKP, Col I, OCN, Runx2, and OPN were detected by using various methods: RT-PCR, AKP activity assay, chemical staining, and western blotting in this study. Col I is the main component of bones, and it increases in the progress of bone formation.…”

Dissecting Collective Cell Behavior in Polarization and Alignment on Micropatterned Substrates

“…Although it is thought to be regulated primarily by spatial gradients of chemical factors known as morphogens (2)(3)(4), recent evidence shows that the mechanical factors also play crucial roles. For instance, there is a wealth of information showing that geometric constraints, such as systematic changes of the area and shape of the substrate using micropatterning techniques, can remarkably influence adhesion-based cell behaviors, regulating the structure of the cytoskeleton, cell migration, differentiation, and apoptosis (5)(6)(7)(8)(9)(10)(11)(12)(13). Particularly at the multicell level, the geometry of the substrate also regulates the orchestration of cell behaviors (14)(15)(16)(17).…”