Journal of Neuro-Oncology

, Volume 106, Issue 2, pp 291–301

Evidence for involvement of ROCK signaling in bradykinin-induced increase in murine blood–tumor barrier permeability

Laboratory Investigation - Human/Animal Tissue


We have previously shown that activation of RhoA by bradykinin (BK) is associated with cytoskeleton rearrangement, tight junction (TJ) protein disassembly, and an increase in blood–tumor barrier (BTB) permeability in rat brain microvascular endothelial cells (RBMECs). Subsequently, we investigated whether Rho-kinases (ROCKs), a family of downstream effectors of activated RhoA known to stimulate F-actin rearrangement, play a key role in the above-mentioned processes in RBMECs. Our study uses primary RBMECs as an in vitro BTB model and a specific ROCK inhibitor (Y-27632) and ROCK II small interfering RNA (siRNA) to establish whether ROCK plays a role in the process of TJ opening by BK. Y-27632 and ROCK II siRNA could partially inhibit endothelial leakage and restored normal transendothelial electric resistance (TEER) values in RBMECs. A shift in occludin and claudin-5 distribution from insoluble to soluble fractions was prevented by Y-27632. Additionally, Y-27632 inhibited BK-induced relocation of occludin and claudin-5 from cellular borders into the cytoplasm as well as stress fiber formation in RBMECs. A time-dependent increase in phosphorylated myosin light chain (p-MLC) and phosphorylated cofilin (p-cofilin) by BK was observed, which was also inhibited by Y-27632. An increase in ROCK activity by BK was inhibited by Y-27632. ROCK’s contribution to BK-induced stress fiber formation is associated with TJ disassembly and an increase in BTB permeability.


ROCK Bradykinin Blood–tumor barrier Tight junction Actin rearrangement Myosin light chain Cofilin 

Copyright information

© Springer Science+Business Media, LLC. 2011

Authors and Affiliations

  1. 1.Department of NeurobiologyCollege of Basic Medicine, China Medical UniversityShenyangPeople’s Republic of China
  2. 2.Institute of Pathology and PathophysiologyChina Medical UniversityShenyangPeople’s Republic of China

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