The Mechanotransduction of ECM-Integrins-Cytoskeleton Signaling to Centrifugal Stress

Objectives: This study was aimed to investigate the role of cytoskeleton in mechanotransduction of centrifugal loading. Methods: Centrifugation is an important step in biochemical and molecular biological researches. The human osteoblast-like cells MG-63 were subjected to a moderate centrifugal stress at 209g for 10 min. Then the gene transcription after centrifugation was analyzed by Real-time RT-PCR detection. And the changes in F-actin and a-actin cytoskeleton, gene transcription of ECM components, and integrins expression were analyzed by LSCM, Real-Time RT-PCR and FCM, respectively. Results: The mRNA expression of Runx2/Cbfa1, Collagen I and osteocalcin changed shortly after centrifugal loading, but recovered to pre-load levels within 24 h. And the fast regulation in the genes investigated was seemed to be related to the integrity of cytoskeleton construction. A temporary and fast reversible change was observed in F-actin and a-actin cytoskeleton within 24 hours. And the change was paralleled with the fast autoregulation in gene transcription of ECM components of fibronection, osteopontin and Collagen I, and integrins expression of both alpha2 and beta1 subunits. Conclusion: The result showed that the osteoblastic cells displayed a fast auto-regulation to usually-used centrifugal stress through the ‘‘extracellular matrix (ECM)-integrins-cytoskeleton'' signal pathway. (supported by RFDP 20060610083)