S-1-propenylcysteine improves TNF-α-induced vascular endothelial barrier dysfunction by suppressing the GEF-H1/RhoA/Rac pathway

Abstract

Background Vascular endothelial barrier function is maintained by cell-to-cell junctional proteins and contributes to vascular homeostasis. Various risk factors such as inflammation disrupt barrier function through down-regulation of these proteins and promote vascular diseases such as atherosclerosis. Previous studies have demonstrated that aged garlic extract (AGE) and its sulfur-containing constituents exert the protective effects against several vascular diseases such as atherosclerosis. In this study, we examined whether AGE and its sulfur-containing constituents improve the endothelial barrier dysfunction elicited by a pro-inflammatory cytokine, Tumor-necrosis factor-α (TNF-α), and explored their mode of action on TNF-α signaling pathway. Methods Human umbilical vein endothelial cells (HUVECs) were treated with test substances in the presence of TNF-α for various time periods. The endothelial permeability was measured by using a transwell permeability assay. The localization of cell-to-cell junctional proteins and actin cytoskeletons were visualized by immunostaining. RhoA and Rac activities were assessed by using GTP-binding protein pulldown assay. Gene and protein expression levels of signaling molecules were analyzed by real-time PCR and western blotting, respectively. Results We found that AGE and its major sulfur-containing constituent, S-1-propenylcysteine (S1PC), reduced hyperpermeability elicited by TNF-α in HUVECs. In addition, S1PC inhibited TNF-α-induced production of myosin light chain (MLC) kinase and inactivation of MLC phosphatase through the suppression of the Rac and RhoA signaling pathways, respectively, which resulted in the dephosphorylation of MLC2, a key factor of actin remodeling. Moreover, S1PC inhibited the phosphorylation and activation of guanine nucleotide exchange factor-H1 (GEF-H1), a common upstream key molecule and activator of Rac and RhoA. These effects of S1PC were accompanied by its ability to prevent the disruption of junctional proteins on the cell–cell contact regions and the increase of actin stress fibers induced by TNF-α. Conclusions The present study suggested that AGE and its major constituent, S1PC, improve endothelial barrier disruption through the protection of junctional proteins on plasma membrane.

Inflammatory Mediators in Atherosclerotic Vascular Remodeling

“…For example, aged garlic extract (AGE) and its sulfur-containing constituents improve the endothelial barrier function elicited by TNFα through stimulation of anti-inflammatory, anti-oxidative and anti-hypersensitive pathways in humans thereby also preventing CVD development including atherosclerosis. Active substances in AGE consisting of S- 1 -prpenylcysteine (S1PC) particularly interfere with TNFα-induced hyperpermeability of the endothelium ( 183 ). Therefore, adverse remodeling in atherosclerosis may also be reduced by food supplements.…”

Griddient: a microfluidic array to generate reconfigurable gradients on-demand for spatial biology applications

“…Once we established a HUVEC monolayer, we exposed the cells to 20 ng/mL TNF-α for 24 h. As expected, treatment with TNF-α induced the generation of pores in the endothelium as well as modifications in cell morphology. These effects of TNF-α have been already described in the literature 17 . (Fig.…”

The Emerging Role of Rho Guanine Nucleotide Exchange Factors in Cardiovascular Disorders: Insights Into Atherosclerosis: A Mini Review

“…Knockdown of RhoA GEF-H1 in vitro contributed to a rise in the endothelial permeability and actin stress fiber formation, suggesting that GEF-H1 is required to maintain the balance between endothelial permeability and barrier integrity ( 58 ). However, AGE and its major constituent, S1PC, inhibited the phosphorylation and activation of GEF-H1 to protect the endothelial barrier through the protection of junctional proteins on plasma membranes ( 59 ). Klems et al used zebrafish embryos and endothelial cell models to show that Rho GEF Trio controlled the formation of enlargement and extension of arterial endothelium.…”