Distinct roles for the small GTPases Cdc42 and Rho in endothelial responses to shear stress
Song Li, … , John Y.-J. Shyy, Shu Chien
Song Li, … , John Y.-J. Shyy, Shu Chien
Published April 15, 1999
Citation Information: J Clin Invest. 1999;103(8):1141-1150. https://doi.org/10.1172/JCI5367.
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Article

Distinct roles for the small GTPases Cdc42 and Rho in endothelial responses to shear stress

Abstract

Shear stress, the tangential component of hemodynamic forces, plays an important role in endothelial remodeling. In this study, we investigated the role of Rho family GTPases Cdc42 and Rho in shear stress–induced signal transduction and cytoskeleton reorganization. Our results showed that shear stress induced the translocation of Cdc42 and Rho from cytosol to membrane. Although both Cdc42 and Rho were involved in the shear stress–induced transcription factor AP-1 acting on the 12-O-tetradecanoyl-13-phorbol-acetate–responsive element (TRE), only Cdc42 was sufficient to activate AP-1/TRE. Dominant-negative mutants of Cdc42 and Rho, as well as recombinant C3 exoenzyme, attenuated the shear stress activation of c-Jun NH2-terminal kinases (JNKs), suggesting that Cdc42 and Rho regulate the shear stress induction of AP-1/TRE activity through JNKs. Shear stress–induced cell alignment and stress fiber formation were inhibited by the dominant-negative mutants of Rho and p160ROCK, but not by the dominant-negative mutant of Cdc42, indicating that the Rho-p160ROCK pathway regulates the cytoskeletal reorganization in response to shear stress.

Authors

Song Li, Benjamin P.C. Chen, Nobuyoshi Azuma, Ying-Li Hu, Steven Z. Wu, Bauer E. Sumpio, John Y.-J. Shyy, Shu Chien

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Figure 5

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Rho is involved in the shear stress regulation of EC alignment and stres...
Rho is involved in the shear stress regulation of EC alignment and stress fiber formation. BAECs cultured on glass slides were transfected with pcDNA3 (1 μg/slide) together with β-gal (1 μg/slide) (a and b), HA-Cdc42(N17) (2 μg/slide) (c and d), and HA-RhoA(N19) (2 μg/slide) (e and f). About 40 h after transfection, the confluent BAEC monolayers were either sheared at 12 dyn/cm2 for 16 h (b, d, and f) or kept under static conditions for 16 h (a, c, and e). The cells were fixed, permeabilized, double stained for actin and the expressed β-gal– or HA-tagged proteins, and observed by confocal microscopy. The actin-based cytoskeletal structure, which was recognized by FITC-conjugated phalloidin, is shown in green; the transfected cells, marked by anti–β-gal mAb or anti-HA mAb recognized by rhodamine-conjugated goat anti-mouse IgG, are shown in red (arrows). Scale bar: 20 μm.