Roflumilast inhibits leukocyte-endothelial cell interactions, expression of adhesion molecules and microvascular permeability

BACKGROUND AND PURPOSE: The present study addressed the effects of the investigational PDE4 inhibitor roflumilast on leukocyte-endothelial cell interactions and endothelial permeability in vivo and in vitro. EXPERIMENTAL APPROACH: In vivo, intravital video-microscopy was used to determine effects of roflumilast p.o. on leukocyte-endothelial cell interactions and microvascular permeability in rat mesenteric venules. In vitro, the effects of roflumilast N-oxide, the active metabolite of roflumilast in humans, and other PDE4 inhibitors on neutrophil adhesion to tumour necrosis factor alpha (TNFalpha)-activated human umbilical vein endothelial cells (HUVEC), E-selectin expression and thrombin-induced endothelial permeability was evaluated. Flow cytometry was used to determine the effect of roflumilast on N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced CD11b upregulation on human neutrophils. KEY RESULTS: In vivo, roflumilast, given 1 h before lipopolysaccharide (LPS), dose-dependently reduced leukocyte-endothelial cell interactions in rat mesenteric postcapillary venules. It also diminished histamine-induced microvascular permeability. Immunohistochemical analyses revealed that roflumilast prevented LPS-induced endothelial P- and E-selectin expression. In vitro, roflumilast N-oxide concentration-dependently suppressed neutrophil adhesion to TNFalpha-activated HUVEC and CD11b expression on fMLP-stimulated neutrophils. It also reduced TNFalpha-induced E-selectin expression on HUVEC, when PDE3 activity was blocked. HUVEC permeability elicited by thrombin was concentration-dependently suppressed by roflumilast N-oxide. While roflumilast N-oxide was as potent as roflumilast at inhibiting stimulated endothelial cell and neutrophil functions, both compounds were significantly more potent than the structurally unrelated PDE4 inhibitors, rolipram or cilomilast. CONCLUSIONS AND IMPLICATIONS: These findings further support earlier observations on the inhibition of inflammatory cell influx and protein extravasation by roflumilast in vivo.     

Cornuside suppresses cytokine-induced proinflammatory and adhesion molecules in the human umbilical vein endothelial cells

Cornuside is a bisiridoid glucoside compound isolated from the fruit of Cornus officinalis SIEB. et ZUCC. The present study was designed to examine the effects of cornuside on expression levels of cytokine-induced proinflammatory and adhesion molecules in the human umbilical vein endothelial cells (HUVECs). Cornuside treatment attenuated tumor necrosis factor-alpha (TNF-alpha)-induced nuclear factor-kappa B (NF-kappaB) p65 translocation in HUVECs. In addition, cornuside suppressed the expression levels of endothelial cell adhesion molecules including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) induced by TNF-alpha. TNF-alpha-induced monocyte chemoattractant protein 1 (MCP-1) expression was also attenuated by treatment of cornuside. These inhibitory effects of cornuside on proinflammatory and adhesion molecules were not due to decreased HUVEC viability as assessed by MTT test. Taken together, the present study suggests that cornuside suppresses expression levels of cytokine-induced proinflammatory and adhesion molecules in the human endothelial cells.     

Humic acid suppresses the LPS-induced expression of cell-surface adhesion proteins through the inhibition of NF-kappaB activation

Humic acid (HA), a potential toxin when penetrating the drinking well water of blackfoot disease-endemic areas in Taiwan, has been implicated as one of the etiological factors of this disease. In this study, we investigated the effects of HA on the expression of human vascular endothelial-leukocyte adhesion molecules and the activation of nuclear factor kappa B (NF-kappaB) in cultured human umbilical vein endothelial cells (HUVECs). The expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin was monitored by flow cytometry. Pretreatment of HUVECs with HA inhibited the lipopolysaccharide (LPS)-induced expression of these three adhesion molecules in a dose- and time-dependent manner. Since NF-kappaB can regulate the expression of these adhesion molecules, NF-kappaB activation was assessed by electrophoretic mobility shift assay (EMSA). Our results reveal that the activation of NF-kappaB by LPS is suppressed by HA in a dose- and time-dependent manner. Furthermore, HA reduces NF-kappaB binding to DNA slightly, but completely inhibits the degradation of IkappaBalpha at a concentration of 100 microg/ml. Thus, all our data demonstrate that HA can inhibit the LPS-induced expression of adhesion molecules through the inhibition of NF-kappaB activation. HA may also suppress the immune or inflammatory reaction of HUVECs responsible for endotoxin, which could be one possible explanation for the causes of the infection and inflammation observed for patients with blackfoot disease. Our results also suggest that immune or inflammatory disturbance occurs for patients with blackfoot disease and that NF-kappaB may be a critical molecule in the pathogenesis of this disease.     

Glabridin suppresses intercellular adhesion molecule-1 expression in tumor necrosis factor-alpha-stimulated human umbilical vein endothelial cells by blocking sphingosine kinase pathway: implications of Akt, extracellular signal-regulated kinase, and nuclear factor-kappaB/Rel signaling pathways

(R)-4-(3,4-Dihydro-8,8-dimethyl)-2H,8H-benzo[1,2-b:3,4-b'] dipyran-3yl)-1,3-benzenediol (glabridin) is known to have anti-inflammatory, antimicrobial, and cardiovascular protective activities. In the present study, we report the inhibitory effect of glabridin on intercellular adhesion molecule-1 (ICAM-1) expression in tumor necrosis factor-alpha (TNF-alpha)-stimulated human umbilical vein endothelial cells (HUVECs). Glabridin inhibited THP-1 cell adhesion to HUVECs stimulated by TNF-alpha and cell surface expression of ICAM-1 in TNF-alpha-stimulated HUVECs. The mRNA expression of adhesion molecules, including ICAM-1, vascular cell adhesion molecule-1, and E-selectin, was also suppressed by glabridin. Further study demonstrated the inhibitory effect of glabridin on nuclear factor (NF)-kappaB/Rel DNA binding, inhibitory factor-kappaB alpha (IkappaB alpha), and IkappaB beta degradation, IkappaB kinase activation, and p65 nuclear translocation in TNF-alpha-stimulated HUVECs. Treatment of a variety of cell lines with glabridin revealed that inhibitory effect of glabridin on NF-kappaB/Rel activation is not cell type-specific, and both inducible and constitutive NF-kappaB/Rel activation was suppressed by glabridin treatment. Moreover, TNF-alpha-induced phosphorylation of Akt and extracellular signal-regulated kinase (ERK) was blocked by glabridin treatment in HUVECs. Glabridin also suppressed sphingosine-1-phosphate (S1P)-induced cell surface expression and mRNA expression of ICAM-1. Further study demonstrated that TNF-alpha-induced sphingosine kinase activity was inhibited by glabridin, and the inhibitory effect of glabridin on TNF-alpha-induced ICAM-1 expression was reversed by addition of exogenous S1P. Together, our results indicate that the inhibitory effect of glabridin on ICAM-1 expression might be mediated, at least in part, by inhibiting sphingosine kinase pathway and subsequent inhibition of signaling pathways, including Akt, ERK, and NF-kappaB/Rel signaling pathway.     

Astragalus polysaccharides suppress ICAM-1 and VCAM-1 expression in TNF-α-treated human vascular endothelial cells by blocking NF-κB activation

Aim:

To investigate the effects Astragalus polysaccharides (APS) on tumor necrosis factor (TNF)-α-induced inflammatory reactions in human umbilical vein endothelial cells (HUVECs) and to elucidate the underlying mechanisms.

Methods:

HUVECs were treated with TNF-α for 24 h. The amounts of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were determined with Western blotting. HUVEC viability and apoptosis were detected using cell viability assay and Hoechst staining, respectively. Reactive oxygen species (ROS) production was measured by DHE staining. Monocyte and HUVEC adhesion assay was used to detect endothelial cell adhesive function. NF-κB activation was detected with immunofluorescence.

Results:

TNF-α (1-80 ng/mL) caused dose- and time-dependent increases of ICAM-1 and VCAM-1 expression in HUVECs, accompanied by significant augmentation of IκB phosphorylation and NF-κB translocation into the nuclei. Pretreatment with APS (10 and 50 μg/mL) significantly attenuated TNFα-induced upregulation of ICAM-1 VCAM-1 and NF-κB translocation. Moreover, APS significantly reduced apoptosis, ROS generation and adhesion function damage in TNF-α-treated HUVECs.

Conclusion:

APS suppresses TNFα-induced adhesion molecule expression by blocking NF-κB signaling and inhibiting ROS generation in HUVECs. The results suggest that APS may be used to treat and prevent endothelial cell injury-related diseases.     

Ginsenoside Rb1 inhibits tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression in human endothelial cells

We investigated whether ginsenoside Rb1 (Rb1) could block tumor necrosis factor-alpha (TNF-alpha)-induced over-expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs) and human lung microvascular endothelial cells (HMVECs-L). Cells were treated with various concentrations of TNF-alpha with or without Rb1 pre-treatment for 16 h. The mRNA and protein levels of VCAM-1 were determined with real-time polymerase chain reaction (PCR) and flow cytometry, respectively. Human monocytic THP-1 cells labeled with fluorescent dye (Calcein-AM) was used for the adhesion assay on HUVEC monolayers. Dihydroethidium (DHE) was used to demonstrate in situ levels of superoxide production. JC-1 dye was used to measure changes in mitochondrial membrane potential. Activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) was determined by Bio-Plex immunoassay. TNF-alpha treatment significantly increased the mRNA and protein levels of VCAM-1 in HUVECs in a dose dependent manner. Rb1 pre-treatment effectively blocked the TNF-alpha-induced expression of VCAM-1 mRNA or protein by 80% and 43%, respectively (p<0.01). THP-1 adhesion was also blocked. Furthermore, Rb1 reduced the TNF-alpha-induced increase of superoxide anion production by 41% and inhibited the TNF-alpha-induced decrease of mitochondrial membrane potential by 44% in HUVECs. Rb1 also effectively blocked TNF-alpha-induced activation of p38, c-Jun N-terminal protein kinase, extracellular signal-regulated kinase 1/2 and IkappaBalpha. In conclusion, Rb1 effectively blocked the TNF-alpha-induced over-expression of VCAM-1, increased THP-1 adhesion and over-production of superoxide anion. Furthermore, Rb1 inhibited TNF-alpha-induced MAPKs and NF-kappaB activation. These data suggested that Rb1 might have potential therapeutic effects in controlling inflammation in vascular diseases.     

Lipopolysaccharide activates nuclear factor kappaB in rat intestine: role of endogenous platelet-activating factor and tumour necrosis factor

1. We examined the effect of lipopolysaccharide (LPS), a cell wall constituent of Gram negative bacteria, on nuclear factor kappaB (NF-kappaB) activation in the intestine and the roles of endogenous platelet-activating factor (PAF), tumour necrosis factor-alpha (TNF) and neutrophils. We also compared the time course of NF-kappaB activation in response to PAF and LPS. 2. Ileal nuclear extracts from LPS (8 mg kg(-1), IV)-injected rats were assayed for NF-kappaB-DNA-binding activity and identification of the subunits. Some rats were pretreated with WEB2170 (a PAF receptor antagonist), anti-TNF antibody, or anti-neutrophil antiserum. NF-kappaB p65 was localized by immunohistochemistry. An additional group was challenged with PAF (2 microg kg(-1), IV) for comparison. 3. LPS activates intestinal NF-kappaB, both as p50-p50 and p50-p65 dimers within 15 min, and the effect peaks at 2 h. The effect is slower and more sustained than that of PAF, which peaks at 30 min. Activated NF-kappaB was immunolocalized within epithelial and lamina propria cells. LPS effect was reduced by 41, 37 and 44%, respectively, in animals pretreated with WEB2170, anti-TNF antibody, or anti-neutrophil antiserum (P<0.05). 4. LPS activates intestinal NF-kappaB in vivo and neutrophil activation is involved in its action. The LPS effect is mediated by both endogenous PAF and TNF.     

参附对脐静脉内皮细胞Toll样受体4/NF-κB途径的影响

目的观察参附注射液对内毒素介导的人脐静脉细胞Toll样受体4/NF-κB途径及细胞间黏附分子、E-选择素表达的影响。方法健康产妇分娩后的新鲜婴儿脐带,应用胶原酶消化,收集内皮细胞进行培养。实验分为对照组、内毒素组、内毒素+参附组。对照组:M199培养基中不加任何物质。内毒素组:M199培养基中加入脂多糖1 mg/L。内毒素+参附组:预先加入参附注射液10 mL/L,30 min后加入脂多糖1 mg/L。干预1h收集细胞,提取核蛋白测定NF-κB活性,干预12 h后收集细胞检测Toll样受体4、细胞间黏附分子1、E-选择素表达水平。结果内毒素组的Toll样受体4、细胞间黏附分子1、E-选择素表达水平、NF-κB活性均显著高于对照组,内毒素+参附组的Toll样受体4、细胞间黏附分子1、E-选择素表达水平、NF-κB活性均明显低于内毒素组。结论参附注射液可以通过抑制NF-κB活化,减弱Toll样受体4/NF-κB途径,抑制了脂多糖介导的黏附分子表达,从而减轻机体的炎症反应。     

The inhibition of neutrophil-endothelial cell adhesion by hyaluronan independent of CD44

Objective: To study the effect of hyaluronan on cell adhesion and recruitment both in vitro and in vivo, since hyaluronan both inhibits restenosis and is anti-inflammatory. When administered to animals undergoing angioplasty the recruitment of cells into the restenotic plaque is inhibited, as well as into inflammatory lesions. The recent discovery that ICAM-1 binds hyaluronan and exhibits the B(X(7))B HA binding motif, led us also to investigate whether cell adhesion could be modulated by hyaluronan. Materials and methods: Human neutrophils were adhered to human umbilical vein (HUVEC) or Ea.hy.926 HUVEC cells stimulated with phorbol myristate acetate (PMA) or tumour necrosis factor (TNFα). Neutrophil binding in vivo utilized FMLP-stimulated hamster cheek pouch post-capillary venules. Results: Hyaluronan inhibited human neutrophil adhesion to both PMA and TNFα-stimulated HUVEC. Ea.hy.926 human immortal HUVECs expressed ICAM-1 in response to TNFα and PMA. E-selectin was also upregulated by 6 h with TNFα but not significantly with PMA. TNFα induced CD44 expression within 4 h, but PMA not significantly up to 6 h. However, specific binding of [¹²⁵I]hyaluronan to Ea.hy.926 cells was increased by PMA-stimulation at 4 h. Neutrophil adhesion to PMA-stimulated Ea.hy.926 HUVECs was inhibited in a concentration dependent fashion by both anti-ICAM-1 and hyaluronan (1 ng/ml-10 μg/ml) at 4 h. At 1 mg/ml adhesion was stimulated by hyaluronan. Hyaluronan had no effect on neutrophil adhesion to resting Ea.hy.926 cells. Hyaluronan (25 mg/kg, i.v.) inhibited cell adhesion to FMLP-stimulated post capillary venules of the hamster cheek pouch, whilst leaving cell rolling unaffected. Conclusions: These results show that hyaluronan, at concentrations below those where intramolecular associations occur, binds selectively to stimulated endothelial cells and inhibits neutrophil adhesion in vitro and in vivo via a mechanism which may involve molecules other than CD44, such as ICAM-1. Deceased.     

Effects of thalidomide on neutrophil respiratory burst, chemotaxis, and transmigration of cytokine- and endotoxin-activated endothelium

Vascular endothelium activated by endotoxin and cytokines plays an important role in organ inflammation and blood leukocyte recruitment. Neutrophils, which are a homogeneous population of effector cells, are rapidly attracted in large numbers to sites of inflammation where they form an early response to infection or injury. Excessive production of various interleukins, TNF, arachidonic acid metabolites, and other substances by neutrophils and macrophages results in systemic endothelial cell injury, a fundamental problem. In the present study, we investigated in vitro the effects of thalidomide (THD) on activation of endothelial cells for enhanced transmigration of neutrophils by lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF), and interleukin-1 (IL-1). Modulation of endotoxin- and cytokine-induced neutrophil chemotaxis and respiratory burst by THD were also studied. Treatment of HUVEC with THD in combination with LPS, TNF, and IL-1, respectively, antagonized LPS-activated transmigration of neutrophils but stimulated the effects of TNF and IL-1. All of the agents used – THD, LPS, TNF, and IL-1 – inhibited neutrophil chemotaxis. Addition of THD to the neutrophils had no effect on LPS-inhibited chemotaxis whereas the TNF- and IL-1-induced chemotaxis was modulated in a bimodal manner. However, THD failed to influence neutrophil respiratory burst activity. Results demonstrate that THD differentially affects mediator-induced activation of HUVEC and neutrophils. Received: 1 April 1997 / Accepted: 4 July 1997     

Suppression of RelA/p65 transactivation activity by a lignoid manassantin isolated from Saururus chinensis

In our search for NF-kappaB inhibitors from natural resources, we have previously identified two structurally related dilignans, manassantin A and B as specific inhibitors of NF-kappaB activation from Saururus chinensis. However, their molecular mechanism of action remains unclear. We here demonstrate that manassantins A and B are potent inhibitors of NF-kappaB activation by the suppression of transciptional activity of RelA/p65 subunit of NF-kappaB. These compounds significantly inhibited the induced expression of NF-kappaB reporter gene by LPS or TNF-alpha in a dose-dependent manner. However, these compounds did not prevent the DNA-binding activity of NF-kappaB assessed by electrophoretic mobility shift assay as well as the induced-degradation of IkappaB-alpha protein by LPS or TNF-alpha. Further analysis revealed that manassantins A and B dose-dependently suppressed not only the induced NF-kappaB activation by overexpression of RelA/p65, but also transactivation activity of RelA/p65. Furthermore, treatment of cells with these compounds prevented the TNF-alpha-induced expression of anti-apoptotic NF-kappaB target genes Bfl-1/A1, a prosurvival Bcl-2 homologue, and resulted in sensitizing HT-1080 cells to TNF-alpha-induced cell death. Similarly, these compounds also suppressed the LPS-induced inducible nitric oxide synthase expression and nitric oxide production. Taken together, manassantins A and B could be valuable candidate for the intervention of NF-kappaB-dependent pathological condition such as inflammation and cancer.     

西洛他唑对磷脂多糖诱导的粘附及粘附分子释放的影响

目的　研究磷酸二酯酶 3型抑制剂西洛他唑对磷脂多糖 (LPS)诱导的粘附及血管内皮细胞 (ECs)释放可溶性细胞粘附分子 (sCAMs)的影响。方法　体外培养第 4～ 6代人脐静脉血管内皮细胞 (HUVECs) ,以LPS(5mg·L- 1)刺激 ,并与西洛他唑 (1～ 10 μmol·L- 1)共培养 2 4h ,观察西洛他唑对由LPS诱导的HUVECs与中性粒细胞之间的粘附的影响 ;另取培养上清 ,以ELISA法测定HUVECs释放可溶性血管细胞粘附分子 1(sVCAM 1)、细胞间粘附分子 1(sICAM 1)以及E 选择素 (sE selectin ,sELAM 1)。结果　西洛他唑抑制由LPS诱导的HUVECs与中性粒细胞之间的粘附以及HUVECs释放sVCAM 1,而对sICAM 1和sE 选择素无影响。并且 ,该药对于sVCAM 1的抑制作用被蛋白激酶A(PKA)抑制剂H 89所阻断。结论　西洛他唑对由细胞因子LPS诱导的粘附反应以及ECs释放sVCAM 1有抑制作用 ,后者可能与PKA依赖性通路相关     

p38 Mitogen-activated protein kinase up-regulates LPS-induced NF-kappaB activation in the development of lung injury and RAW 264.7 macrophages

Clarification of the key regulatory steps that lead to nuclear factor-kappa B (NF-kappaB) under cellular and pathological conditions is very important. The action of p38 mitogen-activated protein kinase (MAPK) on the upstream of NF-kappaB activation remains controversial. To examine this issue using an in vivo lung injury model, SB203580, a p38 MAPK inhibitor was given intraorally 1h prior to lipopolysaccharide (LPS) treatment (intratracheally). The mice were sacrificed 4 h after LPS treatment. SB203580 substantially suppressed LPS-induced rises in p38 MAPK phosphorylation, neutrophil recruitment, total protein content in bronchoalveolar lavage fluid, and apoptosis of bronchoalveolar cells. Furthermore, SB203580 blocked LPS-induced NF-kappaB activation in lung tissue through down-regulation of serine phosphorylation, degradation of IkappaB-alpha, and consequent translocation of the p65 subunit of NF-kappaB to the nucleus. It is likely that, in cultured RAW 264.7 macrophages, SB203580 also blocked LPS-induced NF-kappaB activation in a dose-dependent manner. SB203580 inhibited LPS-induced serine phosphorylation, degradation of IkappaB-alpha, and tyrosine phosphorylation of p65 NF-kappaB. These data indicate that p38 MAPK acts upstream of LPS-induced NF-kappaB activation by modulating the phosphorylation of IkappaB-alpha and p65 NF-kappaB during acute lung injury. Because LPS-stimulated macrophages may contribute to inflammatory lung injury, the inhibition of the p38 MAPK-mediated intracellular signaling pathway leading to NF-kappaB activation represents a target for the attenuation of lung inflammation and parenchymal damage.