Shear stress-induced transcriptional regulation via hybrid promoters as a potential tool for promoting angiogenesis

• Published in: Angiogenesis (London) Vol. 12; no. 3; pp. 231 - 242
• Main Authors: Silberman, Michal, Barac, Yaron D., Yahav, Hava, Wolfovitz, Efrat, Einav, Shmuel, Resnick, Nitzan, Binah, Ofer
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2009; Springer; Springer Nature B.V
• Subjects: Angiogenesis Inducing Agents - metabolism; Animals; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Blood and lymphatic vessels; Blood vessels and receptors; Cancer Research; Cardiology; Cardiology. Vascular system; Cattle; Cell Biology; Cells, Cultured; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Endothelial Cells - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - genetics; HeLa Cells; Humans; Medical sciences; Mice; Neovascularization, Physiologic - genetics; NIH 3T3 Cells; Oncology; Ophthalmology; Organ Specificity - genetics; Original Paper; Promoter Regions, Genetic - physiology; Response Elements - genetics; Response Elements - physiology; Shear Strength - physiology; Stress, Mechanical; Transcription, Genetic - physiology; Transgenes - genetics; Transgenes - physiology; Vertebrates: cardiovascular system; Shear stress; Vascular endothelial cells; Endothelial specific expression; Shear stress response elements; Transcription; Angiogenesis; Endothelial cell; Cardiovascular disease
• ISSN: 0969-6970; 1573-7209
• DOI: 10.1007/s10456-009-9143-7

Among the key effects of fluid shear stress on vascular endothelial cells is modulation of gene expression. Promoter sequences termed shear stress response elements (SSREs) mediate the responsiveness of endothelial genes to shear stress. While previous studies showed that shear stress responsiveness is mediated by a single SSRE, these endogenous promoters often encode for multiple SSREs. Moreover, hybrid promoters encoding a single SSRE rarely respond to shear stress at the same magnitude as the endogenous promoter. Thus, to better understand the interplay between the various SSREs, and between SSREs and endothelial-specific sequences (ESS), we generated a series of constructs regulated by SSREs cassettes alone, or in combination with ESS, and tested their response to shear stress and endothelial specific expression. Among these constructs, the most responsive promoter (NR1/2) encoded a combination of two GAGACC/SSREs, the Sp1/Egr1 sequence, as well as a TPA response element (TRE). This construct was four- to five-fold more responsive to shear stress than a promoter encoding a single SSRE. The expression of constructs containing other SSRE combinations was unaffected or suppressed by shear stress. Addition of ESS derived from the Tie2 promoter, either 5′ or 3′ to NR1/2 resulted in shear stress transcriptional suppression, yet retained endothelial specific expression. Thus, the combination and localization order of the various SSREs in a single promoter is crucial in determining the pattern and degree of shear stress responsiveness. These shear stress responsive cassettes may prove beneficial in our attempt to time the expression of an endothelial transgene in the vasculature.