Abstract 457: Sulforaphane at Physiological Concentrations Inhibits TNF-α-Induced Monocyte Adhesion to Human Vascular Endothelial Cells and Improves Vascular Inflammation in Mice Through a Nuclear Factor-κB--Mediated Mechanism

Abstract

Introduction: TNF-α, plays an important role in endothelial dysfunction and is involved in the pathogenesis of atherosclerosis. Aim: We investigated the protective effect of cruciferous vegetable phytochemical sulforaphane at physiological concentrations on TNF-α-induced vascular inflammation. Methods: Human umbilical vascular endothelial cells (HUVEC) were pretreated with sulforaphane (0.5 - 8 μM) before addition of TNF-α for 6 h. Cell adhesion was measured with calcein-AM labeled human monocytes. In animal study, ten weeks old male C57BL/6 mice were fed a diet containing 0 or 300 ppm sulforaphane for 2 weeks followed by TNF-α administration. The chemokines and adhesion molecules in the serum were measured using ELISA Kit. VCAM-1 and F4/80 expressions in mice aorta were performed using immunohistochemistry. Results: Sulforaphane at physiological concentrations (0.5 - 2 μM) significantly inhibited TNF-α-induced adhesion of monocytes to HUVECs and suppressed TNF-α-induced production of monocyte chemoattractant protein -1 (MCP-1) and interleukin-8 (IL-8). Furthermore, sulforaphane inhibited TNF-α-induced NF-κB transcriptional activity, IκBα degradation and subsequent NF-κB p65 nuclear translocation in endothelial cells, suggesting that sulforaphane can inhibit endothelial inflammation by suppressing NF-κB signaling. In animal study, dietary sulforaphane (300 ppm in the diet) significantly suppressed TNF-α-induced increase in circulating chemokines and adhesion molecules in C57BL/6 mice. Sulforaphane treatment also reduced the presence of VCAM-1 and monocytes-derived F4/80-positive macrophages in the aorta of TNF-α treated mice. Histology showed that sulforaphane treatment significantly prevented the eruption of endothelial lining in the intima layer of the aorta and preserved elastin fibers' delicate organization as shown by Verhoeff-van Gieson staining. Conclusion: sulforaphane at physiological concentrations protects against TNF-α-induced vascular endothelial inflammation, in both in vitro and in vivo models. This anti-inflammatory effect of sulforaphane may be, at least in part, associated with interfering with the NF-κB pathway.

Anti-Inflammatory Therapeutic Mechanisms of Isothiocyanates: Insights from Sulforaphane

“…Inflammation associated with diabetes in mice has been effectively ameliorated by sulforaphane, as shown in high-fat diet- or STZ-induced diabetes and cardiomyopathy [ 200 , 201 ], db / db diabetic mice cardiomyopathy [ 202 ], diabetic cardiomyopathy in both type 1 and type 2 diabetes [ 203 , 204 ], high-fat diet-induced diabetes [ 205 , 206 ], ob/ob diabetic mice [ 90 ], obesity- and type 2 diabetes-associated pain [ 207 ], STZ-induced diabetes [ 208 , 209 ], STZ-induced diabetic nephropathy [ 210 ], type 1 diabetic OVE26 mice [ 211 ], and diabetes-induced vascular inflammation and pathogenesis [ 212 ]. Using a high-fat diet model, the anti-inflammatory effects of sulforaphane in mice have been further shown in [ 213 , 214 ] as well as in American diet-induced inflammation [ 215 ], TNF-α-induced vascular inflammation [ 121 , 122 ], and high-fat diet-induced obesity [ 196 ] models.…”

“…Similarly, sulforaphane has been shown to suppress the expression of pro-inflammatory cytokines in microglial BV2 cells [ 103 , 110 , 113 , 115 ], N9 murine microglial cells [ 105 ], senescent astrocytes [ 108 ], primary co-cultures of rat microglial and astroglial cells [ 111 ], and Müller cells of the retina [ 51 ]. Other inflammation models in vitro where cytokine production has been suppressed by sulforaphane include mast cells [ 102 ], endothelial cells such as human umbilical vein endothelial cells (HUVECs) [ 121 , 122 ], saphenous vein endothelial cell [ 127 ], and transformed endothelial cells such as ECV304 [ 124 ]. Similarly, the upregulation of cytokines’ production in epithelial cells has been shown to be suppressed by sulforaphane, including in Caco-2 [ 135 ], human lung epithelial cells (BEAS-2B) [ 136 , 143 , 145 ], and primary mouse tracheal and human bronchial epithelial cells [ 139 ].…”

“…For example, the induced expression of MCP-1 [ 131 , 143 ] and MCP-1 and chemokine (C-X-C motif) ligand 1 ( CXCL-1 ) [ 136 ] in airway epithelial cells is inhibited. Also, the expression of MCP-1 in HUVECs has been shown to be reduced by sulforaphane [ 119 , 121 , 122 ]. Hence, while multiple mechanisms may be implicated (see the following sections), the major anti-inflammatory mechanism of sulforaphane is attributed to the inhibition of the expression of pro-inflammatory cytokines and chemokines.…”

“…Over the last four decades, numerous research studies have shown that the expression levels of intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin on endothelial cell surfaces provide a good indication of the anti-inflammatory potential of therapeutic agents. In this connection, the endothelial cell surface expression of adhesion molecules such as ICAM-1 [ 124 ], VCAM-1 [ 121 , 122 , 129 ], ICAM-1 and VCAM-1 [ 119 , 120 ], and E-selectin and VCAM-1 [ 128 ] has been shown to be inhibited by sulforaphane. This is also evident in other cell types, including retinal pigment epithelial cells, where the suppression of the expression of ICAM-1 [ 134 ] and, in vascular smooth muscle cells (VSMCs), ICAM and VCAM [ 149 ] or VCAM-1 [ 150 ] has been observed.…”

“…This is also evident in other cell types, including retinal pigment epithelial cells, where the suppression of the expression of ICAM-1 [ 134 ] and, in vascular smooth muscle cells (VSMCs), ICAM and VCAM [ 149 ] or VCAM-1 [ 150 ] has been observed. Similarly, the induced expression of ICAM-1 in epithelial cells by a variety of inflammatory mediators has been shown to be ameliorated [ 120 , 121 , 122 , 134 ]. Consequently, monocyte adhesion to activated endothelial cells has also been shown to be inhibited by sulforaphane [ 120 , 121 , 122 ].…”