Tepoxalin blocks neutrophil migration into cutaneous inflammatory sites by inhibiting Mac-1 and E-selectin expression

A Broad-Spectrum Chemokine-Binding Protein of Bovine Papular Stomatitis Virus Inhibits Neutrophil and Monocyte Infiltration in Inflammatory and Wound Models of Mouse Skin

Bovine papular stomatitis virus (BPSV) is a Parapoxvirus that induces acute pustular skin lesions in cattle and is transmissible to humans. Previous studies have shown that BPSV encodes a distinctive chemokine-binding protein (CBP). Chemokines are critically involved in the trafficking of immune cells to sites of inflammation and infected tissue, suggesting that the CBP plays a role in immune evasion by preventing immune cells reaching sites of infection. We hypothesised that the BPSV-CBP binds a wide range of inflammatory chemokines particularly those involved in BPSV skin infection, and inhibits the recruitment of immune cells from the blood into inflamed skin. Molecular analysis of the purified protein revealed that the BPSV-CBP is a homodimeric polypeptide with a MW of 82.4 kDa whilst a comprehensive screen of inflammatory chemokines by surface plasmon resonance showed high-affinity binding to a range of chemokines within the CXC, CC and XC subfamilies. Structural analysis of BPSV-CBP, based on the crystal structure of orf virus CBP, provided a probable explanation for these chemokine specificities at a molecular level. Functional analysis of the BPSV-CBP using transwell migration assays demonstrated that it potently inhibited chemotaxis of murine neutrophils and monocytes in response to CXCL1, CXCL2 as well as CCL2, CCL3 and CCL5 chemokines. In order to examine the effects of CBP in vivo, we used murine skin models to determine its impact on inflammatory cell recruitment such as that observed during BPSV infection. Intradermal injection of BPSV-CBP blocked the influx of neutrophils and monocytes in murine skin in which inflammation was induced with lipopolysaccharide. Furthermore, intradermal injection of BPSV-CBP into injured skin, which more closely mimics BPSV lesions, delayed the influx of neutrophils and reduced the recruitment of MHC-II+ immune cells to the wound bed. Our findings suggest that the CBP could be important in pathogenesis of BPSV infections.

Restraint stress alters neutrophil and macrophage phenotypes during wound healing

Previous studies reported that stress delays wound healing, impairs bacterial clearance, and elevates the risk for opportunistic infection. Neutrophils and macrophages are responsible for the removal of bacteria present at the wound site. The appropriate recruitment and functions of these cells are necessary for efficient bacterial clearance. In our current study we found that restraint stress induced an excessive recruitment of neutrophils extending the inflammatory phase of healing, and the gene expression of neutrophil attracting chemokines MIP-2 and KC. However, restraint stress did not affect macrophage infiltration. Stress decreased the phagocytic abilities of phagocytic cells ex vivo, yet it did not affect superoxide production. The cell surface expression of adhesion molecules CD11b and TLR4 were decreased in peripheral blood monocytes in stressed mice. The phenotype of macrophages present at the wound site was also altered. Gene expression of markers of pro-inflammatory classically activated macrophages, CXCL10 and CCL5, were down-regulated; as were markers associated with wound healing macrophages, CCL22, IGF-1, RELMα; and the regulatory macrophage marker, chemokine CCL1. Restraint stress also induced up-regulation of IL10 gene expression. In summary, our study has shown that restraint stress suppresses the phenotype shift of the macrophage population, as compared to the changes observed during normal wound healing, while the number of macrophages remains constant. We also observed a general suppression of chemokine gene expression. Modulation of the macrophage phenotype could provide a new therapeutic approach in the treatment of wounds under stress conditions in the clinical setting.

MMP-8 overexpression and persistence of neutrophils relate to stress-impaired healing and poor collagen architecture in mice

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) are critical for tissue remodeling during wound repair. Psychological stress has been found to impair wound healing in humans and animals. The objective of this study was to assess MMP and TIMP gene expression during stress-impaired healing. Female SKH-1 mice (n=299) were divided into control and stress groups (13h restraint/day for 3days prior to and 5days post-wounding). Two 3.5mm cutaneous full-thickness wounds were placed on the dorsum of each mouse and wound measurements were performed daily. RT-PCR for gene expression of MMP-2, MMP-8, MMP-9, TIMP-1 and TIMP-2 was performed at days 1, 3 and 5. Immunohistochemical analyses of the healed wounds were performed at days 15 and 28. As expected, wounds healed more slowly in restraint-stressed mice compared to controls. Stressed mice exhibited MMP-8 overexpression and lower TIMP-1 levels during healing, and poorer collagen organization once healed. MMP-8 overexpression may have stemmed from a higher level of neutrophils, observed in wound tissue on days 3 and 5. These findings implicate higher neutrophil numbers, MMP-8 overexpression, and TIMP-1 under-expression, as mechanisms that may compromise wound outcomes such as scarring under conditions of stress.

Induction of VEGF by tepoxalin does not lead to increased tumour growth in a canine osteosarcoma xenograft

The purpose of this study was to determine the impact of the non-steroidal anti-inflammatory drug tepoxalin on canine tumour cell growth and describe the changes associated with tepoxalin treatment. In vitro experiments were performed to assess tepoxalin-associated alterations in tumour cell growth. Clinically achievable tepoxalin concentrations did not significantly alter tumour cell growth in vitro. Vascular endothelial growth factor (VEGF) production and hypoxia-inducible factor-1α dose-dependently increased in vitro in the presence of tepoxalin. A canine osteosarcoma xenograft was used to determine in vivo effects of tepoxalin on tumour growth and angiogenesis. Despite increased VEGF in vitro, there was a significant growth delay associated with tepoxalin treatment. Normal dogs were administered tepoxalin to assess effects on systemic VEGF production, but not found to have significantly increased VEGF. These data suggest that tepoxalin may moderately inhibit tumour growth and may be administered as an analgesic to tumour-bearing dogs.

Therapeutic potential of selectin antagonists in psoriasis

Psoriasis is a systemic chronic inflammatory disorder. One of the major characteristics is an excess of infiltration of inflammatory cells, mainly lymphocytes, into the skin. Because the adhesion family of selectins is suggested to play a relevant role in this process, selectins have emerged as an interesting target for drug discovery and development in psoriasis. Different strategies targeting selectins have been described. This review discusses these approaches and summarises the current development of selectin antagonists for the treatment of psoriasis. An expert opinion will give the authors' personal opinion about selectin antagonism in psoriasis and which approach might be preferable.

Effect of systemic matrix metalloproteinase inhibition on periodontal wound repair: a proof of concept trial

BACKGROUND

The adjunctive use of matrix metalloproteinase (MMP) inhibitors with scaling and root planing (SRP) promotes new attachment in patients with periodontal disease. This pilot study was designed to examine aspects of the biological response brought about by the MMP inhibitor low dose doxycycline (LDD) combined with access flap surgery (AFS) on the modulation of periodontal wound repair in patients with severe chronic periodontitis.

METHODS

Twenty-four subjects were enrolled into a 12-month, randomized, placebo-controlled, double-masked trial to evaluate clinical, biochemical, and microbial measures of disease in response to 6 months therapy of either placebo capsules + AFS or LDD (20 mg b.i.d.) + AFS. Clinical measures including probing depth (PD), clinical attachment levels (CAL), and bleeding on probing (BOP) as well as gingival crevicular fluid bone marker assessment (ICTP) and microbial DNA analysis (levels and proportions of 40 bacterial species) were performed at baseline and 3, 6, 9, and 12 months.

RESULTS

Patients treated with LDD + AFS showed more potent reductions in PD in surgically treated sites of >6 mm (P<0.05, 12 months). Furthermore, LDD + AFS resulted in greater reductions in ICTP levels compared to placebo + AFS. Rebounds in ICTP levels were noted when the drug was withdrawn. No statistical differences between the groups in mean counts were found for any pathogen tested.

CONCLUSIONS

This pilot study suggests that LDD in combination with AFS may improve the response of surgical therapy in reducing probing depth in severe chronic periodontal disease. LDD administration also tends to reduce local periodontal bone resorption during drug administration. The use of LDD did not appear to contribute to any significant shifts in the microbiota beyond that of surgery alone.

Licofelone, a dual lipoxygenase-cyclooxygenase inhibitor, downregulates polymorphonuclear leukocyte and platelet function

Polymorphonuclear leukocytes are strongly implicated in the pathogenesis of inflammatory disease. Polymorphonuclear leukocyte recruitment at sites of inflammation, mainly sustained by the beta2-integrins, is followed by the synthesis and release of inflammatory mediators, such as leukotrienes, proteolytic enzymes and reactive oxygen species. Functional and metabolic interactions between polymorphonuclear leukocytes and platelets can contribute to and exacerbate the process. The effects of the dual 5-lipoxygenase and cyclooxygenase inhibitor licofelone ([2,2-dimethyl-6-(4-chlorophenyl)-7-phenyl-2,3-dihydro-1H-pyrrolizine-5-yl]-acetic acid) were studied on arachidonic acid transcellular metabolism occurring between polymorphonuclear leukocytes and platelets. The formation of leukotriene C(4), a leukotriene A(4)-derived metabolite, by mixed polymorphonuclear leukocyte/platelet suspensions stimulated with 10 microM A23187 was inhibited by licofelone with an IC(50) of 3.8 +/- 0.07 microM. The formation of 5,12-di-hydroxy-eicosatetraenoic acid (HETE) was abolished at concentrations > or = 10 microM. Licofelone also inhibited the generation of reactive oxygen species by polymorphonuclear leukocytes stimulated with 1 microM n-formyl-methionyl-leucyl-phenylalanine (fMLP), 10 nM complement fraction 5a (C5a) and 1 microM platelet activating factor (PAF) with IC(50)s of 24.4 +/- 0.6, 11.0 +/- 1.5 and 11.7 +/-1.2 microM; elastase release induced by the three agonists was inhibited with IC(50)s of 12.2 +/- 2.2, 23.5 +/- 8 and 2.6 +/- 1 microM, respectively. Homotypic polymorphonuclear leukocyte aggregation induced by fMLP, C5A and PAF was inhibited by licofelone with IC(50)s of 23.7 +/- 4.8, 15.6 +/- 3.4 and 15.4 +/- 4 microM, respectively. The present study extends the anti-lipoxygenase and anti-cyclooxygenase activities of licofelone to the production of arachidonic acid metabolites generated as a consequence of polymorphonuclear leukocyte-platelet transcellular metabolism and to polymorphonuclear leukocyte responses relevant to the pathogenesis of inflammation. The coexistence within the same molecule of a wide spectrum of anti-inflammatory properties is of interest.

Modulation of the host response in periodontal therapy

This paper was prepared by the Research, Science, and Therapy Committee of the American Academy of Periodontology to provide the dental profession an overview of current and potential methods to modulate the host response in the treatment of periodontal diseases. Specifically, it discusses components of periodontal disease pathogenesis (i.e., immune and inflammatory responses, excessive production of matrix metalloproteinases and arachidonic acid metabolites, and regulation of bone metabolism) and their modulation.

Diarylheptanoids suppress expression of leukocyte adhesion molecules on human vascular endothelial cells

Diarylheptanoids possess potent anti-inflammatory properties. However, the mechanism of their action is not fully understood. In this study, we found that three diarylheptanoids, 1-(3, 5-dimethoxy-4-hydroxyphenyl)-7-phenylhept-1-en-3-one (YPE-01), yakuchinone B and demethyl-yakuchinone B, reduced the adhesion of both human monocytic cell line U937 and human eosinophilic cell line EoL-1 cells to tumor necrosis factor-alpha (TNF-alpha)-treated human umbilical vein endothelial cells. In addition, they suppressed interleukin-1beta- or TNF-alpha-induced expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on the surface of the endothelial cells. Since YPE-01 reduced both VCAM-1 and ICAM-1 mRNA induction in TNF-alpha-stimulated endothelial cells, diarylheptanoids appeared to suppress adhesion molecule expression at the transcriptional level. Furthermore, YPE-01 suppressed both VCAM-1 and ICAM-1 mRNA induction as well as edema in 12-O-tetradecanoylphorbol 13-acetate (TPA)-inflamed mice ears in vivo. These results suggest that the anti-inflammatory action of diarylheptanoids is, at least in part, due to their suppressive effect on the surface expression of inducible adhesion molecules in endothelial cells, and subsequent leukocyte adhesion.

Tepoxalin inhibits inflammation and microvascular dysfunction induced by abdominal irradiation in rats

BACKGROUND

Inflammatory cells contribute to the acute and sub-acute sequelae of radiation therapy. Tepoxalin, an inhibitor of cyclooxygenase and 5-lipoxygenase that suppresses NF-kappaB activation, has potent anti-inflammatory activity.

AIMS

To assess the effects of tepoxalin on radiation-induced inflammatory damage, and determine its mechanisms of action.

METHODS

Leucocyte rolling, adhesion and emigration, and albumin leakage were determined by intra-vital microscopy in rat mesenteric venules. NF-kappaB activation was measured by electrophoretic mobility shift assays, and endothelial intercellular adhesion molecule-1 expression by the radiolabelled antibody technique. Groups of irradiated rats were treated with tepoxalin, N-acetyl-L-cysteine, zileuton (lipoxygenase inhibitor), or vehicle.

RESULTS

Irradiated animals had a marked increase in the number of rolling, adherent and emigrated leucocytes in mesenteric venules, and in microvascular permeability. Tepoxalin prevented leucocyte adhesion and the increase in permeability after radiation. Tepoxalin did not inhibit radiation-induced NF-kappaB activation or intercellular adhesion molecule-1 up-regulation, while N-acetyl-L-cysteine, which attenuated NF-kappaB activation, had no effect on leucocyte recruitment. In contrast, tepoxalin inhibited the increase in leukotriene B4 levels after radiation, and the anti-inflammatory effects of the drug were mimicked by zileuton.

CONCLUSIONS

Tepoxalin affords significant protection against radiation-induced inflammation and microvascular dysfunction in splanchnic organs through a mechanism dependent on leukotriene synthesis inhibition.

Anti-Inflammatory Actions of Lipoxin A4 Stable Analogs Are Demonstrable in Human Whole Blood: Modulation of Leukocyte Adhesion Molecules and Inhibition of Neutrophil-Endothelial Interactions

We have examined in whole blood the actions of 2 lipoxin A4 (LXA4) stable analogs, 15-R/S-methyl-LXA4 and 16-phenoxy-LXA4, for their impact on the expression of adhesion molecules on human leukocytes and coronary artery endothelial cells (HCAEC) and on neutrophil adhesion to HCAEC in vitro. Both LXA4 analogs in nanomolar to micromolar concentrations prevented shedding of L-selectin and downregulated CD11/CD18 expression on resting neutrophils, monocytes, and lymphocytes. Changes in CD11/CD18 expression were blocked by the mitogen-activated protein kinase kinase inhibitor PD98059. The LXA4 analogs also attenuated changes in L-selectin and CD11/CD18 expression evoked by platelet-activating factor (PAF), interleukin-8, or C-reactive protein-derived peptide 201-206 with IC50 values of 0.2 to 1.9 μmol/L, whereas they did not affect lipopolysaccharide (LPS)– or tumor necrosis factor-–stimulated expression of E-selectin and intercellular adhesion molecule-1 on HCAEC. These LXA4analogs markedly diminished adhesion of neutrophils to LPS-activated HCAEC. Inhibition of adhesion was additive with function blocking anti–E-selectin and anti–L-selectin antibodies, but was not additive with anti-CD18 antibody. Combining LXA4 analogs with dexamethasone (100 nmol/L) almost completely inhibited PAF-induced changes in adhesion molecule expression on leukocytes and gave additive inhibition of neutrophil adhesion to HCAEC. Culture of HCAEC with dexamethasone, but not with LXA4 analogs, also decreased neutrophil attachment. Together, these results indicate that LXA4 stable analogs modulate expression of both L-selectin and CD11/CD18 on resting and immunostimulated leukocytes and inhibit neutrophil adhesion to HCAEC by attenuating CD11/CD18 expression. These actions are additive with those of glucocorticoids and may represent a novel and potent regulatory mechanism by which LXA4 and aspirin-triggered 15-epi-LXA4 modulate leukocyte trafficking.

Anti-Inflammatory Actions of Lipoxin A4 Stable Analogs Are Demonstrable in Human Whole Blood: Modulation of Leukocyte Adhesion Molecules and Inhibition of Neutrophil-Endothelial Interactions

We have examined in whole blood the actions of 2 lipoxin A4 (LXA4) stable analogs, 15-R/S-methyl-LXA4 and 16-phenoxy-LXA4, for their impact on the expression of adhesion molecules on human leukocytes and coronary artery endothelial cells (HCAEC) and on neutrophil adhesion to HCAEC in vitro. Both LXA4 analogs in nanomolar to micromolar concentrations prevented shedding of L-selectin and downregulated CD11/CD18 expression on resting neutrophils, monocytes, and lymphocytes. Changes in CD11/CD18 expression were blocked by the mitogen-activated protein kinase kinase inhibitor PD98059. The LXA4 analogs also attenuated changes in L-selectin and CD11/CD18 expression evoked by platelet-activating factor (PAF), interleukin-8, or C-reactive protein-derived peptide 201-206 with IC50 values of 0.2 to 1.9 μmol/L, whereas they did not affect lipopolysaccharide (LPS)– or tumor necrosis factor-–stimulated expression of E-selectin and intercellular adhesion molecule-1 on HCAEC. These LXA4analogs markedly diminished adhesion of neutrophils to LPS-activated HCAEC. Inhibition of adhesion was additive with function blocking anti–E-selectin and anti–L-selectin antibodies, but was not additive with anti-CD18 antibody. Combining LXA4 analogs with dexamethasone (100 nmol/L) almost completely inhibited PAF-induced changes in adhesion molecule expression on leukocytes and gave additive inhibition of neutrophil adhesion to HCAEC. Culture of HCAEC with dexamethasone, but not with LXA4 analogs, also decreased neutrophil attachment. Together, these results indicate that LXA4 stable analogs modulate expression of both L-selectin and CD11/CD18 on resting and immunostimulated leukocytes and inhibit neutrophil adhesion to HCAEC by attenuating CD11/CD18 expression. These actions are additive with those of glucocorticoids and may represent a novel and potent regulatory mechanism by which LXA4 and aspirin-triggered 15-epi-LXA4 modulate leukocyte trafficking.

Induction of Cyclooxygenase-2 on Activated T Lymphocytes: Regulation of T Cell Activation by Cyclooxygenase-2 Inhibitors

Cyclooxygenase (COX), known to exist in two isoforms, COX-1 and COX-2, is a key enzyme in prostaglandin synthesis and the target for most nonsteroidal anti-inflammatory drugs. In this study, we show that human T lymphocytes express the COX-2 isoenzyme. COX-2 mRNA and protein were induced in both Jurkat and purified T cells stimulated by TCR/CD3 or PMA activation. COX-2 mRNA was induced very early after activation and superinduced by protein synthesis inhibitors, whereas it was inhibited by the immunosuppressive drug cyclosporin A, identifying it as an early T cell activation gene. Interestingly, treatment with COX-2-specific inhibitors such as NS398 or Celecoxib severely diminished early and late events of T cell activation, including CD25 and CD71 cell surface expression, IL-2, TNF-α, and IFN-γ production and cell proliferation, but not the expression of CD69, an immediate early gene. COX-2 inhibitors also abolished induced transcription of reporter genes driven by IL-2 and TNF-α promoters. Moreover, induced transcription from NF-κB- and NF-AT-dependent enhancers was also inhibited. These results may have important implications in anti-inflammatory therapy and open a new field on COX-2-selective nonsteroidal anti-inflammatory drugs as modulators of the immune activation.

Mechanisms that regulate the function of the selectins and their ligands

Selectins are a family of three cell adhesion molecules (L-, E-, and P-selectin) specialized in capturing leukocytes from the bloodstream to the blood vessel wall. This initial cell contact is followed by the selectin-mediated rolling of leukocytes on the endothelial cell surface. This represents the first step in a cascade of molecular interactions that lead to leukocyte extravasation, enabling the processes of lymphocyte recirculation and leukocyte migration into inflamed tissue. The central importance of the selectins in these processes has been well documented in vivo by the use of adhesion-blocking antibodies as well as by studies on selectin gene-deficient mice. This review focuses on the molecular mechanisms that regulate expression and function(s) of the selectins and their ligands. Cell-surface expression of the selectins is regulated by a variety of different mechanisms. The selectins bind to carbohydrate structures on glycoproteins, glycolipids, and proteoglycans. Glycoproteins are the most likely candidates for physiologically relevant ligands. Only a few glycoproteins are appropriately glycosylated to allow strong binding to the selectins. Recently, more knowledge about the structure and the regulated expression of some of the carbohydrates on these ligands necessary for selectin binding has been accumulated. For at least one of these ligands, the physiological function is now well established. A novel and exciting aspect is the signaling function of the selectins and their ligands. Especially in the last two years, convincing data have been published supporting the idea that selectins and glycoprotein ligands of the selectins participate in the activation of leukocyte integrins.

Adhesion molecules in inflammatory diseases

Cell adhesion molecules (CAM) have a key role in the inflammatory response. Selectins, integrins and immunoglobulin (Ig) gene superfamily adhesion receptors mediate the different steps of the migration of leucocytes from the blood-stream towards inflammatory foci. The activation of endothelial cells (EC) upregulates the expression of several CAM and triggers the interaction of these cells with leucocytes. Selectins are involved in the initial interactions (tethering/rolling) of leucocytes with activated endothelium, whereas integrins and Ig superfamily CAM mediate the firm adhesion of these cells and their subsequent extravasation. During rolling, leucocytes are activated through the intracellular signals generated by CAM and chemokine receptors. Blockade of the function or expression of CAM has emerged as a new therapeutic target in inflammatory diseases. Different drugs are able to interfere with cell adhesion phenomena. In addition, new antiadhesion therapeutic approaches (blocking monoclonal antibodies, soluble receptors, synthetic peptides, peptidomimetics, etc.) are currently in development.

Antiinflammatory effect of tepoxalin: blood and synovial tissue studied in patients with knee arthrosis

Our aim was to determine the amounts of eicosanoids in blood and synovial tissue of patients with knee arthrosis and to examine the effects of 2 doses of tepoxalin (50 mg twice, 200 mg twice), administered p.o. for 3.5 days. Concentrations of leukotriene B4 (LTB4, LTC4, and thromboxane B2 (TXB2) were measured in blood before and after oral administration of tepoxalin and release of prostaglandin E2 (PGE2), 6-keto-PGF1alpha, and LTC4 was measured in incubation media of synovial tissue, taken at surgery from patients treated with tepoxalin. Radioimmunoassay (RIA) was used to determine the levels of the eicosanoids. LT and TXB2 release was reduced by tepoxalin in both doses used. Under these conditions, PGE2, 6-keto-PGF1alpha, and LTC4 release from synovial tissue was detectable only after stimulation with calcium ionophore A23187. Washed synovial tissue, in which tepoxalin concentrations should be reduced, released higher amounts of all eicosanoids measured than directly incubated synovial tissue did. Pain after tepoxalin administration was significantly reduced. Relevant drug concentrations were detected in plasma and synovial fluid. Tepoxalin was well tolerated and had no marked adverse effects. At 400 mg, tepoxalin is a dual inhibitor of cyclooxygenase (CO) and 5-lipoxygenase (5-LO) in blood and synovial tissue.

Inhibition of leukocyte adhesion: an alternative mechanism of action for anti-inflammatory drugs

It has been widely accepted that the mechanism of action of nonsteroidal anti-inflammatory drugs (NSAIDs) is the inhibition of prostaglandin synthesis. However, a significant body of evidence suggests that NSAIDs have additional anti-inflammatory mechanisms of action. Here, Federico Díaz-González and Francisco Sánchez-Madrid discuss novel effects of NSAIDs on leukocyte adhesion pathways that may help in the development of new anti-inflammatory agents that selectively block cell adhesion molecules.

Pharmacological modulation of cell adhesion molecules

Cell adhesion molecules mediate the contact between two cells or between cells and the extracellular matrix. They are essential for morphogenesis, organization of tissues and organs, regulation of immune cell responses and migration of inflammatory cells from the blood vessels into inflamed tissues. Many diseases have been shown to be associated with dysfunction or with overexpression of certain adhesion molecules. Increased cell adhesion molecule function and number are found in clinical disorders in which inflammation and immune cells are involved. Several possible therapeutic agents are described here which have been shown to reduce the expression and/or function of cell adhesion molecules. Anti-adhesion treatment can lead to diminished infiltration and activation of inflammatory immune cells resulting in decreased tissue injury and malfunction.

Dimethylfumarate is an inhibitor of cytokine-induced E-selectin, VCAM-1, and ICAM-1 expression in human endothelial cells

Most studies on the antipsoriatic mode of action of dimethylfumarate focused on its antiproliferative effects in keratinocytes. Because inflammatory skin diseases are associated with an upregulation of endothelial cell adhesion molecules and because the presence of inflammatory cells in dermis and epidermis is considered an important feature in psoriasis, we tested the effect of DMF on cytokine-induced adhesion molecule expression in HUVEC, using in situ ELISA and Northern blotting. Dimethylfumarate inhibited ICAM-1, VCAM-1, and E-selectin expression and reduced adhesion of U937 cells to stimulated HUVEC. Monoethylfumarate and fumaric acid had no effect. Similar inhibitory effects for DMF on VCAM-1 expression were observed after stimulation of HUVEC with LPS, PMA, IL-4, and IL-1 alpha or in combinations with TNF alpha. These data are in agreement with previously reported effects of DMF on intracellular thiol levels and inhibition of NF-kappa B activation. The inhibitory effect on cytokine-induced endothelial adhesion molecule expression may represent another target of dimethylfumarate in psoriasis.