Inhibition Of Intercellular Adhesion Molecule-1 Expression Research Articles

Alantolactone derivatives inhibit the tumor necrosis factor α-induced nuclear factor κB pathway by a different mechanism from alantolactone

Alantolactone is a eudesmane-type sesquiterpene lactone that exerts various biological effects, including anti-inflammatory activity. In the present study, screening using the RIKEN Natural Products Depository chemical library identified alantolactone derivatives that inhibited the expression of intercellular adhesion molecule-1 (ICAM-1) on human umbilical vein endothelial cells stimulated with proinflammatory cytokines and Toll-like receptor ligands. In human lung adenocarcinoma A549 cells stimulated with tumor necrosis factor-α (TNF-α), six alantolactone derivatives inhibited ICAM-1 expression in a dose-dependent manner and at IC50 values of 13–21 μM, whereas that of alantolactone was 5 μM. Alantolactone possesses an α-methylene-γ-lactone moiety, whereas alantolactone derivatives do not. In the nuclear factor κB (NF-κB) signaling pathway, alantolactone prevented the TNF-α-induced phosphorylation and degradation of the inhibitor of NF-κB α (IκBα) protein, and its downstream signaling pathway. In contrast, alantolactone derivatives neither reduced TNF-α-induced IκBα degradation nor the nuclear translocation of the NF-κB subunit RelA, but inhibited the binding of RelA to the ICAM-1 promoter. The inhibitory activities of alantolactone and alantolactone derivatives were attenuated by glutathione. These results indicate that alantolactone derivatives inhibit the TNF-α-induced NF-κB pathway by a different mechanism from alantolactone.

Casticin inhibits interleukin-1β-induced ICAM-1 and MUC5AC expression by blocking NF-κB, PI3K-Akt, and MAPK signaling in human lung epithelial cells.

The compound casticin, isolated from Vitex rotundifolia, exerts anti-inflammatory effects and causes apoptosis of cancer cells. In this study, we explored the anti-inflammatory effects of casticin and modulation of cyclooxygenase (COX)-2, intercellular adhesion molecule 1 (ICAM-1), and mucin 5AC (MUC5AC) expression in interleukin-1β (IL-1β)–activated A549 human pulmonary epithelial cells. A549 cells were treated with various concentrations of casticin (5–20 μM), and an inflammatory response was triggered with interleukin (IL)-1β cytokines. Casticin decreased levels of IL-6, tumor necrosis factor α, and IL-8 and suppressed COX-2 expression and prostaglandin E2 production. It also reduced MUC5AC, proinflammatory cytokine, and chemokine gene expression and inhibited ICAM-1 expression for monocyte adhesion in IL-1β–stimulated A549 cells. In addition, casticin inhibited phosphorylation of Akt, phosphatidylinositol 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) and blocked nuclear transcription factor kappa-B (NF-κB) subunit p65 protein translocation into the nucleus. Co-culture of NF-κB, MAPK, and PI3K inhibitors with casticin also led to more significantly suppressed ICAM-1 expression in inflammatory A549 cells. These results provide evidence that casticin has an anti-inflammatory effect by blocking proinflammatory cytokine, chemokine, and ICAM-1 expression via suppression of the PI3K/Akt, NF-κB, and MAPK signaling pathways in IL-1β–stimulated inflammatory pulmonary epithelial cells.

Thrombin-activated platelet-derived exosomes regulate endothelial cell expression of ICAM-1 via microRNA-223 during the thrombosis-inflammation response

Platelet activation and endothelial damage play essential roles in atherosclerosis. The pathophysiology of this process is mediated by chemokines and exosomes, two critical players in cell communication. Thrombin-activated platelet-derived exosomes have protective effects on atherosclerosis and endothelial inflammation. To confirm these findings, we isolated exosomes using differential ultracentrifugation and transmission electron microscopy. The exosomes were identified using NanoSight-tracking analysis. Immunofluorescence staining and western blotting were performed to assess exosome uptake and intercellular adhesion molecule-1 (ICAM-1) expression in human umbilical vein endothelial cells (HUVECs). We found that the levels of miR-223, miR-339 and miR-21 were elevated in thrombin-activated platelet exosomes. This finding was verified in our atherosclerosis mouse model. We also found that miR-223 transfection in HUVECs inhibited ICAM-1 expression under TNF-α stimulation. Furthermore, the miR-223 inhibitor blocked the downregulating effects of exosomes on ICAM-1 expression. We examined the key proteins of two classical signaling pathways, MAPK and NF-κB, and found that miR-223 inhibited the phosphorylation of p38, JNK and ERK and blocked the nuclear translocation of NF-κB p65. Our results suggest that thrombin-activated platelet-derived exosomes inhibit ICAM-1 expression during inflammation. MiR-223 may mediate this process via regulation of the NF-κB and MAPK pathways.

Abstract 223: Inhibition of STAT3 Phosphorylation by Sulforaphane Reduces Adhesion Molecule Expression in Vascular Endothelial Cell

This study explored the mechanism(s) by which sulforaphane inhibits intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expressions stimulated with lipopolysaccharide (LPS) in human umbilical vein endothelial cell (HUVEC). The protein levels of ICAM-1 and VCAM-1 were investigated by primary antibodies of anti-human ICAM-1, anti-human VCAM-1. The phosphorylation levels of signal transducer and activator of transcription 3 (STAT3) were investigated by phospho-STAT3 antibody. The STAT3-specific small interfering RNA (siRNA) was used to knockdown the expression of STAT3. THP-1 monocyte adhesion photograph images were obtained using a fluorescence microscope. Sulforaphane prevented LPS-mediated increase of ICAM-1 and VCAM-1 expression. Sulforaphane prevented LPS-mediated increase of STAT3 phosphorylation. AG490, Janus kinase (JAK)-2 inhibitor and Stattic, STAT3 inhibitor, reduced LPS-induced the expressions of ICAM-1 and VCAM-1, respectively. STAT3 small interfering RNA (siRNA) treatment reduced ICAM-1 and VCAM-1 expression stimulated with LPS. Sulforaphane reduced LPS-mediated THP-1 monocyte adhesion to HUVEC. These data provide a novel mechanism where sulforaphane decreases an expression of ICAM-1 and VCAM-1 onto vascular wall through an inhibition of STAT3 phosphorylation.

Neuroprotective activity of (1S,2E,4R,6R,-7E,11E)-2,7,11-cembratriene-4,6-diol (4R) in vitro and in vivo in rodent models of brain ischemia

(1S,2E,4R,6R,-7E,11E)-2,7,11-cembratriene-4,6-diol (4R) is a precursor to key flavor ingredients in leaves of Nicotiana species. The present study shows 4R decreased brain damage in rodent ischemic stroke models. The 4R-pretreated mice had lower infarct volumes (26.2±9.7mm3) than those in control groups (untreated: 63.4±4.2mm3, DMSO: 60.2±14.2mm3). The 4R-posttreated rats also had less infarct volumes (120±65mm3) than those in the rats of the DMSO group (291±95mm3). The results from in vitro experiments indicate that 4R decreased neuro2a cell (neuroblastoma cells) apoptosis induced by oxygen–glucose deprivation (OGD), and improved the population spikes’ (PSs) recovery in rat acute hippocampal slices under OGD; a phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin, abolished the effect of 4R on PSs recovery. Furthermore, 4R also inhibited monocyte adhesion to murine brain-derived endothelial (bEND5) cells and upregulation of intercellular adhesion molecule-1(ICAM-1) induced by OGD/reoxygenation (OGD/R), and restored the p-Akt level to pre-OGD/R values in bEND5 cells.In conclusion, the present study indicates that 4R has a protective effect in rodent ischemic stroke models. Inhibition of ICAM-1 expression and restoration of Akt phosphorylation are the possible mechanisms involved in cellular protection by 4R.

Effects of Dictamnus dasycarpus Turcz., root bark on ICAM-1 expression and chemokine productions in vivo and vitro study

Ethnopharmacological relevanceThe root bark of Dictamnus dasycarpus Turcz., family Rutaceae is a well known anti-inflammatory agent for skin diseases such as eczema, pruritus and urticaria in Eastern countries. Materials and methodsWe investigated the effects of methanol extract of Dictamnus dasycarpus root bark (MEDD) on Intercellular Adhesion Molecule-1 (ICAM-1) expression, epidermal hyperplasia and immune cell infiltration in 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced contact dermatitis (CD) mice. We also investigated its effects on the expression of ICAM-1, binding capacity to THP-1 cells, cytokine and chemokine production, and phosphorylation of NF-κB in human keratinocytes (HaCaT cells). ResultsTopical application of MEDD effectively inhibited ICAM-1 expression and epidermal hyperplasia in inflamed tissues. MEDD treatment also inhibited immune cell infiltration induced by DNFB. In addition, treatment with MEDD reduced surface expression and total amount of ICAM-1in HaCaT cells and effectively lowered the capacity to bind to THP-1 cells. MEDD also lowered the levels of IL-6, IL-8, monokine induced by gamma interferon (MIG), monocyte chemotactic protein-1 (MCP-1) and regulated on activation, normal T cell expressed and secreted (RANTES). Finally, MEDD treatment prevented activation of the NF-κB pathway induced by TNF-α in HaCaT cells. ConclusionsThese data indicate that root bark of Dictamnus dasycarpus has the potential for treatment of inflammatory skin diseases as a complementary or alternative medicine to corticosteroids. In addition, they suggest that the anti-inflammatory effects of Dictamnus dasycarpus on CD are involved in the regulation of ICAM-1 expression and cytokine and chemokine secretion through down-regulation of the NF-κB signaling pathway in keratinocytes.

Azelastine enhances the clinical efficacy of glucocorticoid by modulating MKP-1 expression in allergic rhinitis.

Azelastine was suggested as a supplementary choice of glucocorticoid for the control of moderate to severe allergic rhinitis (AR). However, the underlying mechanism has not been completely understood. In this study, primary cultured nasal epithelial cells and bronchial epithelial cells were stimulated with proinflammatory cytokines (IL-1β and IL-17A) and anti-inflammatory agents (azelastine and budesonide) in vitro. The expression of intercellular adhesion molecule 1 (ICAM-1) and mitogen-activated protein kinase phosphatase-1 (MKP-1) was examined using qPCR and ELISA, respectively. Moreover, the additive effects of azelastine and budesonide nasal spray on nasal ICAM-1 level and total nasal symptom scores were evaluated in six uncontrolled severe AR patients by budesonide nasal spray alone. We found azelastine significantly inhibited cytokine-induced ICAM-1 upregulation, which is reversed by MKP-1 silencing. Azelastine and budesonide additively increased MKP-1 expression and inhibited ICAM-1 expression in vitro. After treatment for two consecutive weeks, combined azelastine and budesonide nasal spray significantly decreased nasal ICAM-1 level and TNSS in six uncontrolled AR patients. Our findings suggested that azelastine is able to additively enhance the anti-inflammatory effect of budesonide by modulating MKP-1 expression, which may implicate in the treatment of uncontrolled severe AR.

DaoTan decoction (DTD) inhibits tumor necrosis factor-α (TNF-α)-induced expression of intercellular adhesion molecule-1 (ICAM-1), p53 and p21, in human umbilical vein endothelia cells (HUVECs)

Context: DTD is a Chinese herb prescription used for centuries to treat atherosclerosis or dizziness. Previous studies show that DTD could inhibit ICAM-1 expression induced by TNF-α. However, its mechanism has never been clearly described.Objective: To examine the hypothesis that DTD might inhibit TNF-α-induced ICAM-1 expression through regulating the expression of p53 and p21.Materials and methods: The rats were orally treated with DTD for 3 d (2.3 g/kg per day), and then the serum was collected. HUVECs were cultured and stimulated by TNF-α with or without DTD serum (5, 10, and 20%). The expression of ICAM-1 mRNA was examined by RT-PCR and the expression of p53 and p21 was examined by western blot analysis.Results: The ICAM-1 mRNA levels induced by TNF-α were significantly reduced from 23 to 47%, and the expression of p53 and p21 mRNA levels were significantly reduced from 13 to 43% and 14 to 42%, as the concentration of DTD serum increased. In western blot, TNF-α-induced the expression of p53 and was inhibited from 15 to 53%, by DTD serum in a concentration-dependent manner. TNF-α-induced expression of p21 was inhibited from 2 to 37%, by DTD serum in a concentration-dependent manner.Discussion and conclusion: DTD has a function of “dissolving phlegm”, thus it is chosen for the treatment of atherosclerosis. This study demonstrated that DTD could significantly inhibit the expression of ICAM-1, p53 and p21, which are important factors of atherosclerosis. Therefore, the present study indicates the pharmacological basis for treatment of atherosclerosis with DTD.

Silibinin inhibits ICAM-1 expression via regulation of N-linked and O-linked glycosylation in ARPE-19 cells.

To evaluate the effects of silibinin on intercellular adhesion molecule-1 (ICAM-1) expression, we used ARPE-19 cells as a model in which tumor necrosis factor (TNF-α) and interferon (IFN-γ) enhanced ICAM-1 expression. This upregulation was inhibited by silibinin. In an adherence assay using ARPE-19 and THP-1 cells, silibinin inhibited the cell adhesion function of ICAM-1. The inhibitory effects of silibinin on ICAM-1 expression were mediated via the blockage of nuclear translocation of p65 proteins in TNF-α and phosphorylation of STAT1 in IFN-γ-stimulated cells. In addition, silibinin altered the degree of N-linked glycosylation posttranslationally in ARPE-19 cells by significantly enhancing MGAT3 gene expression. Silibinin can increase the O-GlcNAc levels of glycoproteins in ARPE-19 cells. In a reporter gene assay, PUGNAc, which can also increase O-GlcNAc levels, inhibited NF-κB reporter activity in TNF-α-induced ARPE-19 cells and this process was augmented by silibinin treatment. Overexpression of OGT gene was associated with reduced TNF-α-induced ICAM-1 levels, which is consistent with that induced by silibinin treatment. Taken together, silibinin inhibits ICAM-1 expression and its function through altered O-linked glycosylation in NF-κB and STAT1 signaling pathways and decreases the N-linked glycosylation of ICAM-1 transmembrane protein in proinflammatory cytokine-stimulated ARPE-19 cells.

Human Leukocyte Antigen-G Inhibits Neutrophil Adhesion to Coronary Artery Endothelial Cells Injured by Tumor Necrosis Factor Alpha

Purpose Human Leukocyte Antigen-G (HLA-G) is a non-classical MHC class I molecule and its expression has been associated with immunoprotection of allografts post-transplant. After heart transplantation, allograft survival is often limited by rejection and vasculopathy. Tumor necrosis factor alpha (TNFα) is a cytokine involved in the acute inflammatory response associated with rejection. This inflammatory response includes the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) that cause the adherence of circulating neutrophils to the injured endothelial wall. Our objective was to determine the effect of recombinant HLA-G on neutrophil adhesion to human coronary artery endothelial cells (HCAEC) after TNFα-induced injury. Methods and Materials Commercially available HCAEC (n=8) were cultured to full confluence and exposed to recombinant human HLA-G (1000ng/ml) for 48 hours. The cells were then co-incubated with various doses of TNFα (0.1-1ng/ml) for 4 hours. Neutrophils were isolated from the blood of healthy volunteers and added to HCAEC under nonstatic conditions. The adhesion of neutrophils to HCAEC was measured spectrophotometrically at 492nm. Results Exposure of the HCAEC to 4 hours of treatment with TNFα at concentrations of 0.1, 0.5, and 1ng/ml increased neutrophil adhesion (p Conclusions Our study suggests that HLA-G is a potent inhibitor of neutrophil adhesion to HCAEC subsequent to cytokine-induced injury. A potential mechanism of action of HLA-G could be the inhibition of ICAM-1 expression, which suggests that it may have significant anti-inflammatory properties. Further investigations need to be done to evaluate the precise mechanism of action HLA-G.

Expression of Intercellular Adhesion Molecule 1 by Hepatocellular Carcinoma Stem Cells and Circulating Tumor Cells

Intercellular adhesion molecule 1 (ICAM-1) is believed to be involved in metastasis of hepatocellular carcinoma (HCC) cells. Cancer stem cells promote tumor relapse and metastasis. We investigated whether ICAM-1 is a marker of HCC stem cells. Sphere formation and tumor formation assays were performed to investigate the stem cell properties of ICAM-1(+) cells in vitro and in vivo. A specific targeting system that inhibits ICAM-1 expression and hepatitis B virus transgenic mice (M-TgHBV) were used to investigate whether inhibition of ICAM-1 reduced tumor incidence and metastasis in vivo. We used real-time polymerase chain reaction and immunoblot analysis to assess ICAM-1 and Nanog expression in tumor cell lines, and flow cytometry analysis was used to investigate ICAM-1 expression in HCC and blood samples. ICAM-1 was expressed on a minor cell population in HCC tumor cell lines, as well as in tumor tissues and circulating tumor cells isolated from patients and transgenic mice. ICAM-1(+) tumor cells had greater sphere-forming and tumorigenic capacities and increased expression of stemness-related genes compared with ICAM-1(-) tumor cells. The specific inhibition of ICAM-1 reduced formation and metastasis in M-TgHBV mice. ICAM-1 was found to be a marker of circulating tumor cells from patients and M-TgHBV mice. Increased numbers of CD45(-)ICAM-1(+) cells in blood samples of patients with HCC correlated with worse clinical outcomes. The stem cell transcription factor Nanog regulated expression of ICAM-1 in HCC stem cells. ICAM-1 is a marker of HCC stem cells in humans and mice; ICAM-1 inhibitors slow tumor formation and metastasis in mice. ICAM-1 expression is regulated by the stem cell transcription factor Nanog.

SIRT1 suppresses PMA and ionomycin-induced ICAM-1 expression in endothelial cells

Intercellular adhesion molecule-1 (ICAM-1) plays an important role in the recruitment of leukocytes to the endothelium, which causes inflammation and initiation of atherosclerosis. We have previously shown that endothelium-specific over-expression of class III deacetylase SIRT1 decreases atherosclerosis. We therefore addressed the hypothesis that SIRT1 suppresses ICAM-1 expression in the endothelial cells. Here, we found that expression of SIRT1 and ICAM-1 was significantly induced by PMA and ionomycin (PMA/Io) in human umbilical vein endothelial cells (HUVECs). Adenovirus-mediated over-expression of SIRT1 significantly inhibited PMA/Io-induced ICAM-1 expression in HUVECs. Knockdown of SIRT1 by RNA interference (RNAi) resulted in increased expression of ICAM-1 in HUVECs. Luciferase report assay showed that over-expression of SIRT1 suppressed ICAM-1 promoter activity both in basic and in PMA/Io-induced conditions. We further found that SIRT1 was involved in transcription complex binding on the ICAM-1 promoter by chromatin immunoprecipitation (ChIP) assays. Furthermore, SIRT1 RNAi increased NF-κB p65 binding ability to the ICAM-1 promoter by ChIP assays. Overall, these data suggests that SIRT1 inhibits ICAM-1 expression in endothelial cells, which may contribute to its anti-atherosclerosis effect.

Dao-Tan decoction inhibits tumor necrosis factor-α-induced intercellular adhesion molecule-1 expression by blocking JNK and p38 signaling pathways in human umbilical vein endothelial cells

Context: Dao-Tan decoction (DTD) is a Chinese herb prescription used to treat atherosclerosis or dizziness for centuries. Previous study shows that DTD could inhibit intercellular adhesion molecule-1 (ICAM-1) expression induced by tumor necrosis factor-α (TNF-α). However, its mechanism has never been clearly described.Objective: To examine the hypothesis that DTD might inhibit TNF-α-induced ICAM-1 expression through regulating the mitogen-activated protein kinase (MAPK) pathways, involving Jun N-terminal kinase (JNK) and p38.Materials and methods: The rats were orally administrated with DTD for 3 days (2.3 g/kg per day), then the serum was collected. Human umbilical vein endothelial cells (HUVECs) were cultured and stimulated by TNF-α with or without DTD serum. The expression of ICAM-1 mRNA was examined by reverse transcription-polymerase chain reaction and the expression of p38 and JNK was examined by Western blot analysis. Results: DTD serum significantly inhibits TNF-α-induced ICAM-1 expression by 17–41% on HUVECs. TNF-α-induced JNK and p38 activations, which were involved in ICAM-1 expression, were significantly inhibited with DTD serum treatment by 10–50% on HUVEC.Discussion and conclusion: Based on the theory of traditional Chinese medicine (TCM), pathogenesis of atherosclerosis is caused by “blood” and “phlegm” attached on blood vessels. DTD has a function of “dissolving phlegm”, thus it is chosen for the treatment of atherosclerosis. This study demonstrated that DTD could inhibit the expression of ICAM-1, by significantly preventing the activation of JNK and p38, which are important factors of atherosclerosis. Therefore, the present study indicates the pharmacological basis for treatment of atherosclerosis with DTD.

Glucosamine Modulates TNF-α–Induced ICAM-1 Expression and Function Through O-Linked and N-Linked Glycosylation in Human Retinal Pigment Epithelial Cells

The purpose of this article was to investigate the effects of glucosamine (GlcN) on the TNF-α-induced expression of intercellular adhesion molecule 1 (ICAM-1) and the function of ICAM-1 in ARPE-19 cells in vitro. We quantified protein levels of TNF-α-induced ICAM-1 in ARPE-19 cells with Western blotting. The effects of GlcN on O-linked glycosylation, and therefore on ICAM-1 expression, were compared after the addition of alloxan, an inhibitor of O-linked N-acetylglucosamine transferase (OGT), or O-(2-acetamido-2-deoxy-d-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), an inhibitor of N-acetylglucosaminidase (O-GlcNAcase [OGA]), or after OGT gene overexpression. The effect of GlcN on the N-linked glycosylation of ICAM-1 was evaluated by the change in its molecular mass on Western blotting. The effect of O-linked glycosylation on the nuclear factor κB (NF-κB) signaling pathway was examined using an NF-κB reporter gene assay. The effect of GlcN on ICAM-1 adhesion activity was examined using an ICAM-1 adhesion assay. GlcN, PUGNAc, and OGT overexpression inhibited TNF-α-induced ICAM-1 expression and NF-κB activity in ARPE-19 cells. Alloxan increased ICAM-1 expression and NF-κB activity in TNF-α-induced ARPE-19 cells. GlcN and tunicamycin reduced the molecular mass of TNF-α-induced ICAM-1 in ARPE-19 cells. The proteasome inhibitor MG-132 suppressed the GlcN-induced reduction in the molecular mass of TNF-α-induced ICAM-1. GlcN also attenuated the adhesion activity of TNF-α-induced ICAM-1. GlcN inhibits ICAM-1 expression and functions by modulating the O-linked glycosylation of factors involved in NF-κB signaling and by reducing the N-linked glycosylation of TNF-α-induced ICAM-1 in ARPE-19 cells. These effects may contribute to the GlcN-mediated anti-inflammatory effects in the eye.

Paeoniflorin suppresses the expression of intercellular adhesion molecule‐1 (ICAM‐1) in endotoxin‐treated human monocytic cells

Paeoniflorin (PF) has ameliorative effects on learning and memory impairment and cerebral ischaemia in rats and has protective effects against the degeneration of dopaminergic neurons in substantia nigra. The neuroprotective effects of PF are most probably derived from its anti-inflammatory property. Abnormally high levels of intercellular adhesion molecule-1 (ICAM-1) have been found to be associated with a wide range of inflammatory and immune responses. Here we studied whether PF regulates the levels of ICAM-1 elevated in LPS-activated differentiated human monocytic U937 cells and TNF-α-stimulated human umbilical vein endothelial cells (HUVECs). mRNA levels were evaluated by RT-PCR. Protein levels were evaluated by Western blot analysis. An immunofluorescence technique was used to estimate NF-κB translocation, and NF-κB binding to nuclear DNA was determined by EMSA. PF inhibited ICAM-1 expression elevated in LPS-induced U937 cells and TNF-α-stimulated HUVECs. Although previous reports showed that PF's action is mediated by activating adenosine A₁ receptors, application of a selective adenosine A₁ receptor antagonist did not change the inhibitory effect of PF in our experiments. To elucidate the underlying mechanisms of the effect of PF, we studied its effect on signalling pathways upstream of ICAM-1 expression. PF suppressed the activation of the NF-κB pathway, which regulates the expression of ICAM-1. The TLR4 and MAPK pathways were shown not to be involved in the effects of PF in these cells. PF inhibits ICAM-1 expression in LPS-treated U937 cells and TNF-α-stimulated HUVECs by suppressing the activation of the NF-κB pathway.

Metabolic conversion of dietary flavonoids alters their anti-inflammatory and antioxidant properties

The notion that dietary flavonoids exert beneficial health effects in humans is often based on in vitro studies using the glycoside or aglycone forms of these flavonoids. However, flavonoids are extensively metabolized in humans, resulting in the formation of glucuronide, methyl, and sulfate derivatives, which may have different properties than their parent compounds. The goal of this study was to investigate whether different chemical modifications of the same flavonoid molecule affect its biological and antioxidant activities. Hence, we studied the anti-inflammatory effects of several major human metabolites of quercetin and (−)-epigallocatechin-3-O-gallate (EGCG) by assessing their inhibitory effects on tumor necrosis factor α (TNFα)-induced protein expression of cellular adhesion molecules in human aortic endothelial cells (HAEC). HAEC were incubated with 1–30μM quercetin, 3′- or 4′-O-methyl-quercetin, quercetin-3-O-glucuronide, and quercetin-3′-O-sulfate or 20–100μM EGCG, 4′′-O-methyl-EGCG, and 4′,4′′-di-O-methyl-EGCG, prior to coincubation with 100 U/ml of TNFα. 3′-O-Methyl-quercetin, 4′-O-methyl-quercetin, and their parent aglycone compound, quercetin, all effectively inhibited expression of intercellular adhesion molecule-1 (ICAM-1) with IC50 values (concentration required for 50% inhibition) of 8.0, 5.0, and 4.4μM, respectively; E-selectin expression was suppressed to a somewhat lesser but still significant degree by all three compounds, whereas vascular cell adhesion molecule-1 (VCAM-1) was not affected. In contrast, quercetin-3-O-glucuronide (20–100μM), quercetin-3′-O-sulfate (10–30μM), and phenolic acid metabolites of quercetin (20–100μM) did not inhibit adhesion molecule expression. 4′,4′′-Di-O-methyl-EGCG selectively inhibited ICAM-1 expression with an IC50 value of 94μM, whereas EGCG (20–60μM) and 4′′-O-methyl-EGCG (20–100μM) had no effect. The inhibitory effects of 3′-O-methyl-quercetin and 4′,4′′-di-O-methyl-EGCG on adhesion molecule expression were not related either to inhibition of NF-κB activation or to their antioxidant reducing capacity. Our data indicate that flavonoid metabolites have different biological and antioxidant properties than their parent compounds, and suggest that data from in vitro studies using nonmetabolites of flavonoids are of limited relevance in vivo.

Pentoxifylline inhibits intercellular adhesion molecule-1 (ICAM-1) and lung injury in experimental phosgene-exposure rats

Phosgene inhalation results in acute lung injury (ALI) mostly, pulmonary edema and even acute respiratory distress syndrome, but there is no specific antidote. Inflammatory cells play an important role in the ALI caused by phosgene. Intercellular adhesion molecule-1 (ICAM-1) is a critical factor for inflammatory organ injury. We hypothesized that pentoxifylline (PTX), an inhibitor of leukocyte activation, would have a protective effect on experimental phosgene-induced lung injury rats by inhibiting ICAM-1. To prove this hypothesis, we used rat models of phosgene (400 ppm × 1 min)-induced injury to investigate: (1) the time course of lung injury (control 1, 3, 6, 12, 24, and 48 h group), including pathological changes in hematoxylin and eosin staining and transmission electron microscope, myeloperoxidase (MPO) activity by colorimetric method and ICAM-1 protein level detected by western blot, (2) At 3 h after phosgene exposure, protective effects of different dosages of PTX (50 mg/kg and 100 mg/kg) administration were evaluated by MPO activity, ICAM-1 differential expression and WBC count in bronchoalveolar lavage fluid. The results showed that inflammatory cells emerged out of lung blood vessels at 3 h after phosgene exposure. The MPO activity of lung tissue increased significantly from 3 to 48 h after phosgene exposure (P < 0.05) and ICAM-1 expression presented a similar change, especially at 3 h and 24 h (P < 0.05). After pretreatment and treatment with PTX (100 mg/kg), significant protective effects were shown (P < 0.05). These data supported our hypothesis that PTX reduced phosgene-induced lung injury, possibly by inhibiting ICAM-1 differential expression.

Glycyrrhetinic acid inhibits ICAM-1 expression via blocking JNK and NF-κB pathways in TNF-α-activated endothelial cells

To investigate the effects of glycyrrhetinic acid (GA), an active component extracted from the root of Glycyrrhizae glabra, on the expression of intercellular adhesion molecule-1 (ICAM-1) in tumor necrosis factor-alpha (TNF-alpha)-activated human umbilical vein endothelial cells (HUVEC). ICAM-1 mRNA and protein levels were detected using RT-PCR and cell enzyme-linked immunosorbent assays. The adherence of human monocytic THP-1 cells labeled with [(3)H]thymidine to HUVEC was determined by counting radioactivity with a scintillation counter. The activation of mitogen-activated protein kinases as well as the degradation of I kappaB and nuclear factor-kappaB (NF-kappaB) or phospho-c-Jun in the nucleus were detected by western blots. NF-kappaB binding activity was detected using electrophoretic mobility shift assay. GA (50 and 100 micromol/L) significantly inhibits TNF-alpha-induced ICAM-1 mRNA and protein expressions, as well as THP-1 cell adhesiveness in HUVEC. GA selectively inhibited TNF-alpha-activated signal pathway of c-Jun N-terminal kinase (JNK), without affecting extracellular signal-regulated kinase 1/2 and p38. Furthermore, GA apparently inhibited I kappaB/NF-kappaB signaling system by preventing I kappaB degradation, NF-kappaB translocation, and NF-kappaB/DNA binding activity. Finally, pretreatment with GA or the inhibitors of NF-kappaB, JNK, and p38 reduced the ICAM-1 protein expression induced by TNF-alpha. GA inhibits TNF-alpha-stimulated ICAM-1 expression, leading to a decrease in adherent monocytes to HUVEC. This inhibition is attributed to GA interruption of both JNK/c-Jun and I kappaB/NF-kappaB signaling pathways, which decrease activator protein-1 (AP-1) and NF-kappaB mediated ICAM-1 expressions. The results suggest that GA may provide a beneficial effect in treating vascular diseases associated with inflammation, such as atherosclerosis.

Effects of remifentanil on lipopolysaccharide-induced acute lung injury in rabbits

Objective To investigate the effects of remifentanil on lipopolysaccharide ( LPS)-induced acute lung injury (ALI) in rabbits.Methods Thirty healthy male New Zealand white rabbits weighing 2.5-3.5 kg were randomly divided into 5 groups ( n = 6 each) : group Ⅰ control (group C) ;group Ⅱ ALI;group Ⅲ, Ⅳ, Ⅴ low, median and high dose RF + LPS (group LR, MR, HR) . The animals were anesthetized with intravenous 3% pentobarbital sodium 30 mg/kg, tracheostomized and mechanically ventilated. The carotid artery and jugular vein were cannulated for MAP and HR monitoring, blood sampling, and fluid and drug administration. LPS 0.5 mg/kg in 10 ml of normal saline (NS) was infused over 30 min in group Ⅱ-Ⅴ. Remifentanil 0.2, 0.4 or 0.8 μg·kg~(-1)·min~(-1) was infused starting from 15 min before LPS administration until the death of the animals. MAP, HR, peak airway pressure (P_(peak) ), PaO_2 and plasma intercellular adhesion molecule 1 (ICAM-1) concentration were measured immediately before LPS infusion (T_0, baseline) and at 1, 2.5 and 5.5 h after the end of LPS infusion. The animals were killed and the lungs were immediately removed for microscopic examination and determination of W/D lung weight ratio. Results MAP, HR and PaO_2 were significantly decreased while W/D ratio and P_(peak) were significantly increased after iv LPS infusion as compared with control group. LPS significantly increased plasma ICAM-1 concentration and damaged the structure of lung tissue. Remifentanil infusion significantly attenuated the LPS-induced changes in a dose-dependent manner. Conclusion RF has protective effect against LPS-induced ALI and inhibition of ICAM-1 expression is involved in the mechanism. Key words: Piperidines; Endotoxemia; Respiratory distress syndrome; adult

Antisense inhibition of ICAM-1 expression as therapy provides insight into basic inflammatory pathways through early experiences in IBD

Background: Alicaforsen (ISIS 2302), an antisense to intercellular adhesion molecule-1 (ICAM-1) (CD54), was designed to inhibit ICAM-1 expression. ICAM-1 seems to play a role in cell-mediated inflammation, specifically cell trafficking. For this reason, it may be useful in a variety of immune-mediated diseases, including inflammatory bowel disease. Objective: To evaluate the use of alicaforsen in clinical trials to understand its efficacy and side effects, as well as assess for evidence that may offer insight into disease pathways. Methods: We evaluate all of the available, published trials, with a focus on the prospective, randomized trials. Results/conclusions: Systemic treatment for Crohn's disease has not revealed significant effect. Topical enemas for ulcerative colitis have demonstrated some effect in secondary outcomes, and initial studies in pouchitis are promising. In general, the compound has been well tolerated and safe.