Induced apoptosis of osteoblasts proliferating on polyhydroxyalkanoates

• Published in: Biomaterials 2013-05, Vol.34 (15), p.3737-3746
• Main Authors: Wang, Yang, Jiang, Xian-Li, Peng, Si-Wu, Guo, Xiao-Yong, Shang, Guan-Guan, Chen, Jin-Chun, Wu, Qiong, Chen, Guo-Qiang
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Animals; Apoptosis; Apoptosis - drug effects; Biomaterials; Biomedical materials; Caspase 8 - metabolism; Caspase-8; Cell Adhesion - drug effects; Cell Cycle - drug effects; Cell Proliferation - drug effects; Cells, Cultured; Copolymers; Dentistry; Electrochemical machining; Enzyme Activation - drug effects; Extracellular Matrix - genetics; Extracellular Matrix - metabolism; Integrin; Integrin beta3 - genetics; Integrin beta3 - metabolism; Microscopy, Atomic Force; Osteoblast; Osteoblasts; Osteoblasts - cytology; Osteoblasts - drug effects; Osteoblasts - metabolism; Osteoblasts - ultrastructure; Polyhydroxyalkanoates; Polyhydroxyalkanoates - pharmacology; Proliferation; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Surface Properties - drug effects; Surgical implants; TCP (protocol); Thermodynamics
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/j.biomaterials.2013.01.088

Abstract The mechanism study on behaviors of cells influenced by biomaterial surface properties can provide profound guidances for functional tissue engineering scaffolds design. In this study, regulation of integrin-mediated cell–substrate interactions using rat osteoblasts incubated on PHA films was investigated. Compared with tissue culture plate (TCP), poly-3-hydroxybutyrate (PHB), copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV) and copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx), osteoblasts inoculated on a terpolymer of 3-hydroxybutyrate, 3-hydroxyvalerate and 3-hydroxyhexanoate (PHBVHHx) were found to have higher apoptosis rates. Several integrin subunits in osteoblasts grown on PHBVHHx showed altered expressions. Simultaneously, extracellular matrics (ECM) were also remodeled on the material surface. Osteoblasts showed a higher expression of integrin subunit β3 and αv on PHBVHHx films compared with that on TCP. On the other hand, less vitronectin, osteopontin and fibronectin, the main ligands for integrin β3 were expressed and deposited in ECM. The unligated integrin β3 could recruit caspase-8 to the membrane and activate its downstream signaling which was proven by the caspase-8 activation assay. It was therefore concluded that the induced apoptosis of osteoblasts on PHBVHHx was regulated by recruitment of caspase-8 to the unligated integrin β3.