CV-159, a Unique Dihydropyridine Derivative, Prevents TNF-Induced Inflammatory Responses in Human Umbilical Vein Endothelial Cells

[Fuxinfang improves hypoxia-induced injury of human aortic endothelial cells by regulating c-Fos-NR4A1-p38 pathway]

OBJECTIVE

To explore the molecular mechanism of Fuxinfang for improving injury of human aortic endothelial progenitor cells (HAECs).

OBJECTIVE

Serum samples were collected from male SD rats treated with Fuxinfang (n=8) or saline (n= 5). HAECs cultured in normoxia or hypoxic condition (2% O₂) were treated with serum from normal rats or with diluted serum (1% and 10%) from rats treated with Fuxinfang. The differentially expressed genes (DEGs) between Fuxinfang-treated and control cells were detected using high-throughput sequencing to screen the target DEGs that participated in arterial endothelial cell injury and underwent changes in response to both hypoxia and Fuxinfang treatment. AmiGo and String databases were used to infer the interactions among the target genes, and the expressions of the genes were analyzed in HAECs with different treatments using enzyme-linked immunosorbent assay (ELISA) and Western blotting.

OBJECTIVE

HAECs cultured in hypoxia did not show obvious changes in cell morphology or expressions of hypoxia-related factors in response to treatment with 1% or 10% serum from Fuxinfang-treated rats. The results of high-throughput sequencing showed a total of 7134 DEGs (4205 up-regulated and 2929 down-regulated genes) in HAECs in hypoxia model group and 762 DEGs (305 upregulated and 457 down-regulated genes) in Fuxinfang-treated HAECs. Analysis of AmiGo and String databases and the constructed protein-protein interaction network identified c-Fos, NR4A1, and p38MAPK as the target genes. The results of ELISA and Western blotting showed that the expressions of c-Fos, NR4A1, p38MAPK and pp38MAPK increased significantly in cells with hypoxic exposure (P < 0.05); treatment with the serum containing Fuxinfang significantly reduced the expression levels of c-Fos, NR4A1 and p-p38MAPK in hypoxic HAECs in a concentration-dependent manner (P < 0.05).

OBJECTIVE

The serum from Fuxinfang-treated rats can concentration-dependently inhibit the expressions of the DEGs occurring in hypoxia. Fuxinfang improves hypoxic injuries of HAECs possibly by down-regulating the expression of c-Fos to inhibit NR4A1 expression and suppressing hypoxia-induced p38 phosphorylation.

Mechanisms underlying a decrease in KCl-induced contraction after long-term serum-free organ culture of rat isolated mesenteric artery

Organ culture of blood vessel is a better technique to investigate the long-term effects of drugs. However, some functional changes may occur from freshly isolated vessel (Fresh). Mammalian/mechanistic target of rapamycin (mTOR) regulates smooth muscle differentiation and Ca²⁺ mobilization. We thus investigated mechanisms of alteration in smooth muscle contractility after serum-free organ culture focusing on mTOR. Rat isolated mesenteric arteries were cultured for 5 days without (0% serum) or with rapamycin. In 0% serum, absolute contraction by KCl significantly decreased from Fresh, which was significantly rescued by rapamycin. In 0% serum, mTOR expression significantly increased from Fresh, which was significantly rescued by rapamycin. In 0% serum, expression of myocardin, a key regulator of smooth muscle differentiation markers, significantly decreased from Fresh, which was significantly rescued by rapamycin. However, the decrease in expression of contractile proteins, including SM22α and calponin, was not changed by rapamycin. Basal phosphorylation of calmodulin-dependent protein kinase II significantly increased in 0% serum, which was significantly rescued by rapamycin. In 0% serum, absolute contraction by caffeine significantly decreased from Fresh, which was significantly rescued by rapamycin. In conclusion, expression of mTOR increased during serum-free organ culture of rat isolated mesenteric artery for 5 days, which may be at least partly responsible for the decreased smooth muscle contractility perhaps due to the decrease in the stored Ca²⁺ in smooth muscle.

TNFα signals via p66(Shc) to induce E-Selectin, promote leukocyte transmigration and enhance permeability in human endothelial cells

Endothelial cells participate in inflammatory events leading to atherogenesis by regulating endothelial cell permeability via the expression of VE-Cadherin and β-catenin and leukocyte recruitment via the expression of E-Selectins and other adhesion molecules. The protein p66^Shc acts as a sensor/inducer of oxidative stress and may promote vascular dysfunction. The objective of this study was to investigate the role of p66^Shc in tumor necrosis factor TNFα-induced E-Selectin expression and function in human umbilical vein endothelial cells (HUVEC). Exposure of HUVEC to 50 ng/ml TNFα resulted in increased leukocyte transmigration through the endothelial monolayer and E-Selectin expression, in association with augmented phosphorylation of both p66^Shc on Ser³⁶ and the stress kinase c-Jun NH₂-terminal protein kinase (JNK)-1/2, and higher intracellular reactive oxygen species (ROS) levels. Overexpression of p66^Shc in HUVEC resulted in enhanced p66^Shc phosphorylation on Ser³⁶, increased ROS and E-Selectin levels, and amplified endothelial cell permeability and leukocyte transmigration through the HUVEC monolayer. Conversely, overexpression of a phosphorylation-defective p66^Shc protein, in which Ser³⁶ was replaced by Ala, did not augment ROS and E-Selectin levels, nor modify cell permeability or leukocyte transmigration beyond those found in wild-type cells. Moreover, siRNA-mediated silencing of p66^Shc resulted in marked reduction of E-Selectin expression and leukocyte transmigration. In conclusion, p66^Shc acts as a novel intermediate in the TNFα pathway mediating endothelial dysfunction, and its action requires JNK-dependent phosphorylation of p66^Shc on Ser³⁶.

Eukaryotic elongation factor 2 kinase regulates the development of hypertension through oxidative stress-dependent vascular inflammation

Eukaryotic elongation factor 2 kinase (eEF2K) is a Ca2+/calmodulin-dependent protein kinase. We recently demonstrated that eEF2K protein increases in mesenteric artery from spontaneously hypertensive rats (SHR). Pathogenesis of hypertension is regulated in part by vascular inflammation. We tested the hypothesis whether eEF2K mediates vascular inflammatory responses and development of hypertension. In vascular endothelial cells, small interfering RNA (siRNA) against eEF2K inhibited induction of VCAM-1 and endothelial-selectin as well as monocyte adhesion by TNF-α (10 ng/ml). eEF2K siRNA inhibited phosphorylation of JNK and NF-κB p65 as well as reactive oxygen species (ROS) production by TNF-α. In vascular smooth muscle cells, eEF2K siRNA also inhibited VCAM-1 induction and phosphorylation of JNK and NF-κB by TNF-α. In vivo, increased blood pressure in SHR and ROS production, induction of inflammatory molecules, and hypertrophy in SHR superior mesenteric artery were reduced by an eEF2K inhibitor NH125 (500 μg·kg(-1)·day(-1)). In SHR superior mesenteric artery, impairment of ACh-induced relaxation was normalized by NH125. The present results for the first time demonstrate that eEF2K mediates TNF-α-induced vascular inflammation via ROS-dependent mechanism, which is at least partly responsible for the development of hypertension in SHR.

Death-Associated Protein Kinase 3 Mediates Vascular Inflammation and Development of Hypertension in Spontaneously Hypertensive Rats

Death-associated protein kinase (DAPK) is a Ca 2+ /calmodulin-regulated serine/threonine kinase that mediates cell death. Our recent study demonstrated that DAPK3 protein increases in the mesenteric artery from spontaneously hypertensive rats compared with Wistar Kyoto rats. Pathogenesis of hypertension is modulated at least in part by vascular inflammation. We examined whether DAPK3 mediates vascular inflammatory responses and development of hypertension. In rat mesenteric arterial smooth muscle cells, small interfering RNA against DAPK3 inhibited vascular cell adhesion molecule 1 expression and monocyte adhesion induced by tumor necrosis factor-α. DAPK3 small interfering RNA inhibited phosphorylation of c-Jun amino-terminal kinase, p38, and Akt, as well as reactive oxygen species (ROS) production induced by tumor necrosis factor-α. In human umbilical vein endothelial cells, expressions of vascular cell adhesion molecule 1, endothelial selectin, and cyclooxygenase 2, as well as ROS production induced by tumor necrosis factor-α, were inhibited by DAPK inhibitor. In vivo, blood pressure, ROS production, inflammatory molecule expression (vascular cell adhesion molecule 1 and endothelial selectin), and hypertrophy in isolated mesenteric artery were elevated in spontaneously hypertensive rats (10 weeks old), which were prevented by long-term treatment with a DAPK inhibitor (500 µg/kg per day for 6 weeks). In isolated mesenteric artery, the increased angiotensin II–induced contraction and the impaired acetylcholine-induced endothelium-dependent relaxation in spontaneously hypertensive rats were reversed by a DAPK inhibitor. The present results for the first time demonstrated in cultured smooth muscle cells and endothelial cells that DAPK3 mediates tumor necrosis factor–induced inflammatory responses via ROS-dependent mechanisms. It is also suggested that DAPK3 mediates the development of hypertension in spontaneously hypertensive rats likely via ROS-dependent inflammation, hypertrophy, and hypercontractility.

Influences of organic solvents on CYPMPO-electron spin resonance spectra in in vitro radical generating systems

Estimation of radical scavenging capacity of lipophilic antioxidants by electron spin resonance (ESR) in vitro is a challenging issue due to their poor solubility in aqueous radical generating and measuring systems. Water-miscible organic solvents are used for this purpose. A novel radical trapping agent, 5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO), that has practical advantages over well-known trapping agents was synthesized. However, no available data for the influence of solvents in an ESR system that uses CYPMPO has been presented. The influences of six water-miscible organic solvents, acetonitrile (AcN), acetone, dimethyl sulfoxide (DMSO), ethanol, polyethylene glycol (PEG), and dimethoxyethane (DME), on ESR responses to Fenton Fe(2+)/H (2)O(2 )OH· and hypoxanthine/xanthine oxidase superoxide generation systems in vitro were studied. Reduction of the ESR signal to CYPMPO-OH· adducts by 55.86 ± 5.95 and 83.17 ± 2.50% compared with the control was observed in the presence of AcN and acetone, respectively, at a final concentration of 5% (v/v). AcN of less than 1% had minimal effects. DMSO, ethanol, PEG and DME at 5% (v/v) strongly inhibited the ESR signals and/or caused derangement in the signal patterns. The six water-miscible solvents at 5% (v/v) had no influence on the ESR spectra of CYPMPO-superoxide adducts. From these results, AcN, at less than 1% (v/v), is a useful water-miscible organic solvent for assessing radical scavenging capacities of lipophilic compounds in the CYPMPO-Fenton Fe(2+)/H(2)O(2) OH· reaction system in an ESR assay. Any of the solvents used in the present study can be used in a hypoxanthine/xanthine oxidase superoxide generation system.