- 作者：K. Sliogeryte&dagger ; ; &Dagger ; ; L. Botto&dagger ; ; D.A. Lee&dagger ; ; M.M. Knight&dagger ; ; m.m.knight@qmul.ac.uk" class="auth_mail" title="E-mail the corresponding author
- 关键词：Chondrocyte dedifferentiation ; Micropipette aspiration ; Cell mechanics ; ERM proteins ; Membrane-actin interaction
- 刊名：Osteoarthritis and Cartilage
- 出版年：2016
- 出版时间：May 2016
- 年：2016
- 卷：24
- 期：5
- 页码：912-920
- 全文大小：1703 K
Method
Micropipette aspiration was used to estimate the viscoelastic properties of freshly isolated articular chondrocytes and the same cells after passage in monolayer. Studies quantified the cell membrane-actin cortex adhesion by measuring the critical pressure required for membrane detachment and bleb formation. We then examined the expression of ezrin, radixin and moesin (ERM) proteins which are involved in linking the membrane and actin cortex and combined this with theoretical modelling of bleb dynamics.
Results
Dedifferentiated chondrocytes at passage 1 (P1) were found to be stiffer compared to freshly isolated chondrocytes (P0), with equilibrium modulus values of 0.40 and 0.16 kPa respectively. The critical pressure increased from 0.59 kPa at P0 to 0.74 kPa at P1. Dedifferentiated cells at P1 exhibited increased cortical F-actin organisation and increased expression of total and phosphorylated ERM proteins compared to cells at P0. Theoretical modelling confirmed the importance of membrane-actin cortex adhesion in regulating bleb formation and effective cellular elastic modulus.
Conclusion
This study demonstrates that chondrocyte dedifferentiation in monolayer strengthens membrane-actin cortex adhesion associated with increased F-actin organisation and up-regulation of ERM protein expression. Thus dedifferentiated cells have reduced susceptibility to bleb formation which increases cell modulus and may also regulate other fundamental aspects of cell function such as mechanotransduction and migration.