title: Inserted rest period resensitizes MC3T3-E1 cells to fluid shear stress in a time-dependent manner via F-actin-regulated mechanosensitive channel(s).
abstract: The underlying cellular mechanism of anabolic effect recovered by inserting rest is not fully understood. In this work, we studied the role of F-actin regulated mechanosensitive channel(s) re-activation in mechanosensitivity modulation in vitro. Results showed that steady fluid shear stress (sFSS) stimulation with 30-min rest period was more potential in increasing alkalinephosphatase (ALP) activity than 10 and 0-min rest periods, and insertion of 30 min, but not 0 or 10 min, recovered the [Ca(2+)]i transient and contribution of the mechanosensitive channel(s). During the rest period, F-actin experienced polymerization (0-10 min), followed by depolymerization (10-30 min); inhibition of F-actin polymerization/depolymerization significantly increased/decreased the [Ca(2+)]i transient, as well as the contribution of the mechanosensitive channel(s) in subsequent sFSS stimulation. Our results demonstrated that the long rest period between sFSS loadings recruited [Ca(2+)]i transient via F-actin depolymerization-induced reactivation of mechanosensitive channel(s), suggesting that F-actin-regulated cellular stiffness could account for the decreased anabolic response during continuous mechanical loading in bone cells.
authors.affiliation: a Key Laboratory for Biorheological Science and Technology of Ministry of Education , College of Bioengineering, Chongqing University , Chongqing , China.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Gong
authors.forename: Yijuan
authors.initials: Y
authors.lastname: Fan
authors.forename: Yinxin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chunhua
authors.initials: C
authors.lastname: Luo
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Duan
authors.forename: Liu
authors.initials: L
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Pan
mesh_terms: D016475:3T3 Cells; D000199:Actins / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D002118:Calcium / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D051379:Mice; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D000199:Actins; D007473:Ion Channels; D000469:Alkaline Phosphatase; D002118:Calcium
keywords: bone cells; cytoskeleton; fluid shear stress (FSS); inserted rest period; mechanosensitivity