title: Evidence for involvement of ROCK signaling in bradykinin-induced increase in murine blood-tumor barrier permeability.
abstract: 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.
authors: Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang, 110001 Liaoning, People's Republic of China.
authors: Teng
authors: T
authors: Ma
authors: Libo
authors: L
authors: Liu
authors: Ping
authors: P
authors: Wang
authors: Yixue
authors: Y
authors: Xue
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000201:enzymology* / Q000473:pathology; D015153:Blotting, Western; D001920:Bradykinin / Q000494:pharmacology; D001932:Brain Neoplasms / Q000201:enzymology* / Q000473:pathology; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D034622:RNA Interference; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D019108:Tight Junctions / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology; D054460:rho-Associated Kinases / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D054460:rho-Associated Kinases; D001920:Bradykinin