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.

Neutrophils engage the kallikrein‐kinin system to open up the endothelial barrier in acute inflammation

“…The reorganization of the actin cytoskeleton induced by neutrophils in ECs and the capacity of BAPTA/fasudil treatment to prevent gap formation suggest a role of actomyosin contraction in the EC response upon neutrophil degranulation and activation of BK B 2 receptors. The mechanisms downstream of BK B 2 receptor signaling eventually leading to openings of endothelial cell junctions have been investigated and suggested to involve VE-cadherin disassembly (36) and increased actomyosin interaction (37). Although it was beyond the scope of our study to define the involvement of these cellular responses in further detail, our data do not exclude a role of VE-cadherin disassembly in parallel with actin reorganization.…”

Potential Regulatory Effects of Corticotropin-Releasing Factor on Tight Junction-Related Intestinal Epithelial Permeability are Partially Mediated by CK8 Upregulation

“…F-actin is a major contractile protein of the cytoskeleton, and its reorganization and redistribution in epithelial cells may impair intestinal barrier function by altering the structure of intestinal TJ-associated proteins. Cytoskeletal actin links to the C-terminal region of TJ protein ZO-1 and influences its expression and structure [33]. Cytoplasmic protein ZO-1 could further bind to the C-terminal binding sequence of the transmembrane protein claudin-1 and participate in maintaining the stability of epithelial TJ [6, 34, 35].…”

Renin-angiotensin system (RAS) blockade attenuates growth and metastatic potential of renal cell carcinoma in mice

“…First, blockade of ACE increases the bradykinin concentration, and it is known that the kinin system influences carcinogenesis by stimulating the growth, survival, and migration of cancer cells by altering the permeability of the blood tumor barrier and through the release of proinflammatory cytokines [35][36][37][38]. In addition, Fernandes et al [39], using a murine model of Ehrlich tumor, found that bradykinin antagonists may inhibit tumor growth.…”