title: 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.
authors.affiliation: Key Laboratory of Microgravity and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Ruirong
authors.initials: R
authors.lastname: Fu
authors.forename: Qinli
authors.initials: Q
authors.lastname: Liu
authors.forename: Guanbin
authors.initials: G
authors.lastname: Song
authors.forename: Andrew
authors.initials: A
authors.lastname: Baik
authors.forename: Man
authors.initials: M
authors.lastname: Hu
authors.forename: Shujin
authors.initials: S
authors.lastname: Sun
authors.forename: X Edward
authors.initials: XE
authors.lastname: Guo
authors.forename: Mian
authors.initials: M
authors.lastname: Long
authors.forename: Bo
authors.initials: B
authors.lastname: Huo
mesh_terms: D016475:3T3 Cells; D000199:Actins / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D002454:Cell Differentiation; D049109:Cell Proliferation; D048430:Cell Shape; D015638:Cytochalasin D / Q000737:chemistry; D020287:In Situ Nick-End Labeling; D051379:Mice; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology; D010012:Osteogenesis; D015398:Signal Transduction / Q000235:genetics; D013499:Surface Properties
chemical_list: D000199:Actins; D015638:Cytochalasin D; D000469:Alkaline Phosphatase