Modulation Of Adhesion Molecules Research Articles

Nitric oxide reduces T lymphocyte adhesion to human brain microvessel endothelial cells via a cGMP-dependent pathway

The entry of lymphocytes into the brain is normally limited by the blood–brain barrier, however, during inflammation prominent lymphocytic infiltration occurs. In this study, we investigated the effects of nitric oxide (NO) on the adhesion of T cells to cultured human brain microvessel endothelial cells. T cell adhesion to unstimulated or tumor necrosis factor-alpha (TNF-α)-treated cells was quantified by counting the number of lymphocytes bound to the monolayer by light microscopy. TNF-α increased T cell adhesion in a time-dependent manner. Incubation of monolayers with NO donors decreased adhesion. This effect was blocked by a guanylyl cyclase inhibitor and mimicked by a cGMP agonist, and was thus dependent on the generation of cGMP. NO did not modulate adhesion molecule expression in the endothelial cells, suggesting an action on the T cells. Pre-treatment of T cells with NO or a cGMP agonist decreased binding to recombinant endothelial adhesion molecules. These findings suggest that NO can modulate the adhesion of T cells to human brain microvessel endothelial cells via a cGMP-dependent mechanism, and may thus regulate lymphocyte traffic during central nervous system inflammation.

Polyunsaturated fatty acids and inflammation

The n-6 polyunsaturated fatty acid, arachidonic acid, is a precursor of prostaglandins, leukotrienes and related compounds that have important roles as mediators and regulators of inflammation. Consuming increased amounts of long chain n-3 polyunsaturated fatty acids (found in oily fish and fish oils) results in a partial replacement of the arachidonic acid in cell membranes by eicosapentaenoic and docosahexaenoic acids. This leads to decreased production of arachidonic acid-derived mediators. This alone is a potentially beneficial anti-inflammatory effect of n-3 fatty acids. However, n-3 fatty acids have a number of other effects that might occur downstream of altered eicosanoid production or are independent of this. For example, they result in suppressed production of pro-inflammatory cytokines and can modulate adhesion molecule expression. These effects occur at the level of altered gene expression.

Development of Non-Anticoagulant Derivatives of Biotechnology Derived Sulfaminoheparosan Derivatives to Investigate the Non-Anticoagulant Effects of these Agents.

It is now well known that heparin and related glycosaminoglycans produce some of their non-anticoagulant effects such as the anti-inflammatory, antiproliferative and regulatory actions independent of endogenous serpine (AT and HC-II). Sulfaminoheparosans (SAH) represent a class of biotechnology derived bacterial capsular polysaccharide (K5) derivatives which are epimerized and sulfated to mimic heparin's biologic effects and exhibit affinity to both AT and HC-II. These SAH can be produced to exhibit molecular profile mimicking the low molecular weight heparins (LMWHs). The disaccharide unit structure of epimerized SAH is GlcA-GlcNSO36SO3(3,6)H) in comparison to heparin which is IdoA2SO3-GlcNSO36SO3. The anticoagulant and antiprotease profile of a 6 kDa SAH has been found to be similar to Tinzaparin (Maddineni et al. Clin Appl Thromb Hemost 10(1):27–37,2004). As this agent also exhibits various other biologic effects such as the release of TFPI, modulation of adhesion molecules and antiproliferative effects, it was hypothesized that the non-anticoagulant forms of this agent may exhibit some of these effects. In order to produce the non-anticoagulant derivatives in 6 kDa SAH, desulfated derivatives were prepared by removing sulfate groups on the position 2 alone (2 desulfated) and positions 2 and 6 (2,6 desulfated derivatives). Additional modifications in the 2,6 desulfated derivatives included the presence of either free amino group or N-acetyl in position 2. These modifications did not result in the molecular weight profile of the desulfated derivatives. However, in comparison to the parent 6 kDa SAH both the 2-desulfated and 2,6 desulfated derivatives were weaker in the anticoagulant (PT, PTT, Heptest) and antiprotease (anti-Xa, anti-IIa) and protease generation assays. 2,6 desulfation produced a strong decrease in the anticoagulant effects. Furthermore, the desulfation was proportional to a decrease in the affinity to AT and HC-II. None of these agents produced any activation of ADP induced platelet aggregation, however in whole blood flowcytometric studies ADP induced aggregation was augmented by 6 kDa SAH whereas the mono and disulfated derivatives produced variable effects. Heparinase I and II did not produce any digestion of any of these derivatives. Incubation of the 6 kDa SAH and the 2 desulfated and 2,6 disulfated derivatives produced varying degrees of inhibition of the Lewis-lung carcinoma cell cultures which was not dependent on degree of sulfation. These studies suggest that the non-serpine mediated effect of these agents may be independent of the sulfation pattern and the relative anticoagulant effects of these sulfaminoheparosan.

Reduction in adhesiveness to extracellular matrix components, modulation of adhesion molecules and in vivo migration of murine macrophages infected with Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite, able to disseminate into deep tissues and cross biological barriers, reaching immunoprivileged sites such as the brain and retina. In order to investigate whether the parasite uses leukocyte trafficking to disseminate throughout the host, the adhesive potential to extracellular matrix components, the expression of adhesion molecules and the in vivo migration of murine macrophages infected with RH strain of T. gondii were investigated. Cellular adhesion to fibronectin, laminin and collagen IV decreased after 24 h of T. gondii infection. However, the decrease in adhesion of infected macrophages observed at early infection was reversed after 48 h. Moreover, decreased adhesion was dependent on active penetration, since heat-killed parasites were unable to reproduce it. Expression of integrins αL, α4 and α5 chains was downmodulated early postinfection, but a progressive regain of expression was observed after 12 h of infection. Expression of β2, αv and α4 integrins by peritoneal macrophages at late infection was also gradually reestablished. The assessment of in vivo migration of infected macrophages labeled with the fluorescent dye 5-chloromethylfluorescein diacetate showed a 48-h delay in migration to cervical lymph nodes when compared to LPS pre-stimulated macrophages. Furthermore, cells that migrate to distal lymph nodes were loaded with live parasites. Taken together, these results provide insights about T. gondii escape from the host immune response, placing the macrophage as a “Trojan horse”, contributing to parasite dissemination and access to immunoprivileged sites.

Leukocyte CD11b and CD62L Expression in Response to Interstitial Inflammation in CAPD Patients

Very little is known about the kinetics of leukocyte recruitment and the modulation of adhesion molecules on leukocytes in the interstitium at the site of inflammation outside the peritoneal cavity in patients on peritoneal dialysis. These issues were addressed in the present study. Two skin blisters were raised in 10 patients on peritoneal dialysis and in 19 healthy subjects. After 12 hours, blister exudates were collected and the blisters were thereafter challenged with buffer or autologous serum in order to establish an intermediate and an intense cutaneous inflammation. Leukocyte count, leukocyte CD11b/CD62L expression, monocyte chemotactic protein-1 (MCP-1), and interleukin-8 (IL-8) were determined in blood and at the three sites of interstitial inflammation by immunostaining, flow cytometry, and ELISA. In monocytes and granulocytes, expression of CD11b increased and CD62L decreased significantly during the transmigration process from the peripheral blood into the three sites of interstitial inflammation. In the nonstimulated blister, expression of CD11b on both monocytes and granulocytes was similar in patients and healthy subjects. At the site of intermediate inflammation, expression of CD11b on both monocytes and granulocytes was significantly higher in healthy subjects compared to patients (p < 0.05 and p < 0.001 respectively). At the site of intense inflammation, expression of CD11b on granulocytes was significantly lower (p < 0.001), and CD62L significantly higher (p < 0.001) in patients. Interstitial concentrations of MCP-1 and IL-8 at the sites of intermediate inflammation were significantly higher in healthy subjects compared to patients (p < 0.05 and p < 0.05 respectively). However, at the site of intense inflammation, similar concentrations of MCP-1 and IL-8 were observed. Furthermore, there were no significant correlations between concentrations of MCP-1 and IL-8 in blister exudates and expression of CD11b on monocytes and granulocytes at the sites of interstitial inflammation. The ability of monocytes and granulocytes to modulate the expression of adhesion molecule in response to interstitial inflammation was significantly impaired in patients on peritoneal dialysis. Furthermore, these data suggest that the expression of CD11b on leukocytes is not dependent on concentrations of IL-8 and MCP-1 in interstitium in this patient group.

Influence of Retinoic Acid on Adhesion Complexes in Human Hepatoma Cells: A Clue to Its Antiproliferative Effects

Retinoic acid exerts antiproliferative and differentiative effects in normal and transformed in vitro hepatocytes. In order to verify whether these effects are related to a modulation of adhesion molecules, we used Western blot analysis and immunofluorescence microscopy to investigate the E-cadherinl/beta-catenin complex, the main system of adherens junctions, and the occludin/ZO-1 complex present in the tight junctions in HepG2 cells cultured in the presence or absence of retinoic acid. Results showed that retinoic acid treatment increases the amount of beta-catenin bound to E-cadherin by decreasing its tyrosine-phosphorylation level. Similar results were obtained with the tight junction system, in which the amount of occludin/ZO-1 complex is increased by a similar mechanism that reduced the level of ZO-1 phosphorylation on tyrosine. Immunofluorescence images also confirm these results, showing the localization on the cell surface of both adhesion complexes. Their insertion into the plasma membrane could be suggestive of an optimal reassembly and function of adherens and tight junctions in hepatoma cells, indicating that retinoic acid, besides inhibiting cell proliferation, improves cell-cell adhesion, sustaining or inducing the expression of a more differentiated phenotype.

Unfractionated and Low-Molecular-Weight Heparins, Basic Mechanism of Action and Pharmacology

Unfractionated heparin has enjoyed sole anticoagulant status for nearly 50 years. Despite a dramatic growth in the development and the introduction of many newer anticoagulant and antithrombotic drugs and polytherapeutic approaches during the past decade, unfractionated and low-molecular-weight heparins remain the drugs of choice for many indications, including surgical anticoagulation, interventional cardiology, and in several additional considerations. Unfractionated heparin has a major role in the areas of vascular medicine and surgery, and it is the only parenteral anticoagulant drug that can be empirically neutralized by such agents as protamine sulfate. The development of low and ultra low-molecularweight heparins, which are a class of depolymerized heparin derivatives with distinct pharmacologic profiles that are largely determined by their composition, represents a refinement for the use of heparin. These drugs produce their major effects by combining with antithrombin Ill and exerting antithrombin and anti-Xa inhibition. The low-molecular-weight heparins also increase non-antithrombin III-dependent effects, such as tissue factor pathway inhibitor release, modulation of adhesion molecules, and the release of profibrinolytic and antithrombotic mediators from the blood vessels. Each of the low-molecular-weight heparins has different cumulative effects, and each product exhibits a distinct profile. Initially developed for the prophylaxis of postsurgical deep vein thrombosis, these drugs are now also used for the treatment of both venous and arterial thrombotic disorders. To a large extent, the low-molecular-weight heparins have replaced unfractionated heparin in most of the subcutaneous indications. This has resulted in a dramatic evolution in anticoagulant management that allows patients with thrombotic disorders to be treated in an outpatient setting. Thus, the introduction of low-molecular-weight heparins represents a major advance in improving the use of heparin. Generic versions of these drugs are likely to be developed as their patents expire. Currently, there are no clear guidelines for the acceptance of the generic versions of branded products. To avoid safety and efficacy-related problems, a generic drug must meet both the chemical and biologic equivalence criterion. Synthetically and biosynthetically derived agents such, as pentasaccharide, will also be introduced for clinical use; however, these drugs will have a narrower therapeutic spectrum due to their monotherapeutic nature. Heparin and its derivatives will continue to have a crucial role in the management of thrombotic and cardiovascular disorders in years to come.

Up-regulation of the endothelial cell adhesion molecule intercellular adhesion molecule-1 (ICAM-1) by autoantibodies in autoimmune vasculitis.

Autoimmune vasculitis is characterized by the presence of autoantibodies, particularly anti-neutrophil cytoplasmic antibodies (ANCA) and anti-nuclear antibodies (ANA), in patient sera. These autoantibodies have an incompletely understood role in development of vascular injury. The expression or up-regulation of cell adhesion molecules is an early phase in the development of an inflammatory vascular lesion. Autoantibody-positive sera from patients with vasculitis were assessed for their ability to modulate adhesion molecule expression by human umbilical vein endothelial cells (HUVEC). Autoantibody-positive serum samples from 11 out of 21 patients with primary vasculitis produced substantial up-regulation of ICAM-1 on HUVEC. Autoantibody-negative samples did not produce adhesion molecule up-regulation. Up-regulation of adhesion molecules on HUVEC was observed with samples positive for ANA, a phenomenon not previously reported. Preincubation of the sera with purified antigens recognized by ANCA failed to block this activation. In addition, MoAbs to ANCA antigens were ineffective at inducing ICAM-1 up-regulation, suggesting that activation is independent of the molecular specificity of the antibody. This capacity of ANCA- and ANA-positive sera to up-regulate adhesion molecules on endothelial cells may be a factor in the vessel wall inflammation seen in ANCA-associated vasculitis.

ONO-6818, a novel, potent neutrophil elastase inhibitor, reduces inflammatory mediators during simulated extracorporeal circulation

Background Among the serine proteases, neutrophil elastase is a powerful cytotoxic enzyme and plays a pivotal role in the inflammatory response associated with cardiopulmonary bypass. This study assesses the effects of the specific inhibition of neutrophil elastase by a novel, potent, low-molecular-weight neutrophil elastase inhibitor, ONO-6818. We hypothesized that ONO-6818 reduces inflammatory mediators and modulates adhesion molecules and the deformability of neutrophils during simulated extracorporeal circulation. Methods Simulated extracorporeal circulation was established by recirculating fresh heparinized (3.75 U/mL) human blood for 120 minutes in a membrane oxygenator and a roller pump with and without 1.0 μmol/L of ONO-6818 (n = 9 for control group, n = 7 for ONO-6818 group). The neutrophil adhesion molecules, CD11b and L-selectin, and the cytoplasmic F-actin of neutrophils were measured by flow cytometry. Neutrophil deformability was evaluated using simulated silicon microcapillaries. Neutrophil elastase, interleukin 8, and C5b-9 were measured using enzyme immunoassay. Results Neutrophil elastase levels were significantly lower in the ONO-6818 group. ONO-6818 significantly reduced interleukin 8 and C5b-9 production. ONO-6818 did not modulate changes of CD11b and L-selectin during recirculation. Cytoplasmic F-actin content and changes of neutrophil deformability did not significantly differ between the groups. Conclusions Inhibition of neutrophil elastase activity with ONO-6818 reduces further interleukin 8 production and the formation of the complement membrane attack complex, and this results in a reduction of neutrophil elastase levels during simulated extracorporeal circulation. This study suggests that specific neutrophil elastase inhibition with ONO-6818 is a feasible therapeutic option to attenuate the exaggerated inflammatory response associated with cardiopulmonary bypass.

Thalidomide: a new anticancer drug?

Experimental studies have demonstrated that thalidomide (Thal), a drug developed as a sedative, has antitumoural properties. The possible antitumour mechanisms of action involve: inhibition of angiogenesis, cytokine-mediated pathways, modulation of adhesion molecules, inhibition of cyclooxygenase-2 and stimulation of immuno response. Therefore, Thal is under clinical evaluation in oncology. This paper provides an overview of the data currently available in literature regarding, in terms of activity and toxicity, the use of Thal in cancer patients. Multiple myeloma is so far the most responsive malignancy. A moderate activity has been documented in certain solid tumours: glioblastoma multiforme, renal cell carcinoma and malignant melanoma. Tolerability is generally satisfactory with peripheral neuropathy being the most relevant dose-dependent toxicity. The more frequent, but moderate side effects are: somnolence, constipation, dizziness and fatigue. More studies are needed to properly evaluate the anticancer activity of Thal alone or in combination with other anticancer treatments. Preliminary studies suggest promising results of Thal in combinations with corticosteroids and cytotoxic drugs as front-line therapy of multiple myeloma. Regarding therapy of solid tumours in the adult, combination with chemotherapy, radiation therapy and molecular-targeting compounds are under investigation.

CAP37, a neutrophil-derived inflammatory mediator, augments leukocyte adhesion to endothelial monolayers

Cationic antimicrobial protein of molecular weight 37 kDa (CAP37) is a multifunctional inflammatory mediator that was originally isolated from human neutrophils and described to possess bactericidal and monocyte-activating functions. More recently its expression in endothelial and epithelial cells in response to inflammatory mediators and its ability to activate endothelial cells and alter permeability has been demonstrated. We hypothesize that CAP37 facilitates the process of transendothelial migration not only because of its potential to act as a chemoattractant but also through its ability to promote leukocyte adhesion to the endothelium by modulating adhesion molecule expression on the endothelium. Here we describe its ability to mediate neutrophil and monocyte adherence to endothelial monolayers in vitro. Using reverse transcriptase–polymerase chain reaction and flow cytometry, we demonstrate its ability to upregulate the adhesion molecules, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin in human umbilical vein and lung microvessel endothelial cells. The identity and kinetics of upregulation of the specific adhesion molecule was dependent on the endothelial cell type, suggesting that adhesion molecules on endothelial cells from different vascular beds are differentially regulated by CAP37. The cell-specific kinetics of adhesion molecule upregulation by CAP37 may influence selective leukocyte migration in certain inflammatory situations.

N-3 polyunsaturated fatty acids and inflammation: from molecular biology to the clinic.

The immune system is involved in host defense against infectious agents, tumor cells, and environmental insults. Inflammation is an important component of the early immunologic response. Inappropriate or dysfunctional immune responses underlie acute and chronic inflammatory diseases. The n−6 PUFA arachidonic acid (AA) is the precursor of prostaglandins, leukotrienes, and related compounds that have important roles in inflammation and in the regulation of immunity. Feeding fish oil results in partial replacement of AA in cell membranes by EPA. This leads to decreased production of AA-derived mediators, through several mechanisms, including decreased availability of AA, competition for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, and decreased expression of COX-2 and 5-LOX. This alone is a potentially beneficial anti-inflammatory effect of n−3 FA. However, n−3 FA have a number of other effects that might occur down-stream of altered eicosanoid production or might be independent of this effect. For example, dietary fish oil results in suppressed production of proinflammatory cytokines and can modulate adhesion molecule expression. These effects occur at the level of altered gene expression. Fish oil feeding has been shown to ameliorate the symptoms of some animal models of autoimmune disease and to protect against the effects of endotoxin. Clinical studies have reported that oral fish oil supplementation has beneficial effects in rheumatoid arthritis and among some asthmatics, supporting the idea that the n−3 FA in fish oil are anti-inflammatory. There are indications that the inclusion of fish oil in enteral and parenteral formulae is beneficial to patients.

Human natural killer cell activity against porcine targets: modulation by control of the oxidation–reduction environment and role of adhesion molecule interactions

Xenotransplantation, especially using porcine sources, has been proposed as a means to alleviate the shortage of human organs for transplantation. NK cells appear to be important mediators of the xenogeneic immune responses, including the human anti-pig response. Having previously established the redox regulation of NK cell activity against tumor target cells, we now report that the interaction of human NK cells with porcine target cells is also regulated by redox. Thiol-deprivation strongly diminished the capacity of IL-2-activated human NK cells to kill porcine endothelial cells. This inhibition correlated with reduced proliferation and interferon (IFN)-γ production by IL-2-activated NK cells. For fresh NK cells, pretreatment with diethyl maleate (DEM), which was used to deplete intracellular thiols, reduced lysis of porcine and human targets. Because many adhesion molecules exhibit interspecies recognition, we further investigated whether changes in expression of adhesion molecules might explain our observations. DEM treatment reduced the expression of CD11b and CD29 on fresh NK cells. Monoclonal antibody blocking studies showed that the combination of mAb to CD11b and CD18 reduced lytic activity against both PAEC as well as K562, although other qualitative differences were observed between the porcine and human target cells. These findings suggest that the oxidative stress-induced downregulation of CD18 may be important in modulating cytotoxic activity of fresh NK cells against PAEC and K562 targets through reduced formation of the CD11b/CD18 heterodimer. Thus, the appropriate manipulation of redox status may provide a means to enhance survival of non-human animal tissues in humans through modulation of adhesion molecule expression/interactions.

Thalidomide: a new anticancer drug?

Experimental studies have demonstrated that thalidomide (Thal), a drug developed as a sedative, has antitumoural properties. The possible antitumour mechanisms of action involve: inhibition of angiogenesis, cytokine-mediated pathways, modulation of adhesion molecules, inhibition of cyclooxygenase-2 and stimulation of immuno response. Therefore, Thal is under clinical evaluation in oncology. This paper provides an overview of the data currently available in literature regarding, in terms of activity and toxicity, the use of Thal in cancer patients. Multiple myeloma is so far the most responsive malignancy. A moderate activity has been documented in certain solid tumours: glioblastoma multiforme, renal cell carcinoma and malignant melanoma. Tolerability is generally satisfactory with peripheral neuropathy being the most relevant dose-dependent toxicity. The more frequent, but moderate side effects are: somnolence, constipation, dizziness and fatigue. More studies are needed to properly evaluate the anticancer activity of Thal alone or in combination with other anticancer treatments. Preliminary studies suggest promising results of Thal in combinations with corticosteroids and cytotoxic drugs as front-line therapy of multiple myeloma. Regarding therapy of solid tumours in the adult, combination with chemotherapy, radiation therapy and molecular-targeting compounds are under investigation.

Monocyte Adhesion Molecule Modulation by Lipid Microenvironment

Conference Abstract| July 01 2002 Monocyte Adhesion Molecule Modulation by Lipid Microenvironment J Sarma; J Sarma Search for other works by this author on: This Site PubMed Google Scholar KAA Fox; KAA Fox Search for other works by this author on: This Site PubMed Google Scholar C Haslett; C Haslett Search for other works by this author on: This Site PubMed Google Scholar I Dransfield I Dransfield Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (2002) 103 (s47): 7P. https://doi.org/10.1042/cs103007P Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation J Sarma, KAA Fox, C Haslett, I Dransfield; Monocyte Adhesion Molecule Modulation by Lipid Microenvironment. Clin Sci (Lond) 1 July 2002; 103 (s47): 7P. doi: https://doi.org/10.1042/cs103007P Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 2002 The Biochemical Society and the Medical Research Society2002 Article PDF first page preview Close Modal You do not currently have access to this content.

Outer membrane vesicles from Neisseria meningitidis.

Flow cytometry was used to study the expression of leukocyte adhesion molecules CD11a, CD11b, CD11c, CD14, and CD62L (L-selectin) and production of reactive oxygen species (ROS) in an ex vivo human whole-blood system stimulated with lipopolysaccharide-containing outer membrane vesicles (LPS-OMV) from N. meningitidis. Results demonstrated a dose-dependent increase in surface expression of CD11a, CD11b, CD11c and CD14 in granulocytes and monocytes (maximal at 30-120 min) upon OMV-LPS challenge, whereas CD62L expression was heavily downregulated (maximal at 30-120 min). The OMV-associated LPS was almost as potent (on a weight basis) as purified LPS from E. coli in inducing adhesion molecule modulation but the response was delayed. Upon stimulation with OMV-LPS or E. coli-LPS, the production of intracellular ROS increased in both granulocytes and monocytes when dihydroethidium (DHE, mainly reflecting superoxide anion) was used as a probe, whereas peroxynitrite production monitored with dihydrorhodamine 123 (DHR) was not significantly changed. The OMV-mediated modulation of leukocyte adhesion molecule expression and increased ROS production may certainly lead to increased entrapment of leukocytes in the microcirculation and contribute to untoward inflammatory reactions as seen in systemic meningococcal disease.

Heme is a potent inducer of inflammation in mice and is counteracted by heme oxygenase.

Various pathologic conditions, such as hemorrhage, hemolysis and cell injury, are characterized by the release of large amounts of heme. Recently, it was demonstrated that heme oxygenase (HO), the heme-degrading enzyme, and heme are able to modulate adhesion molecule expression in vitro. In the present study, the effects of heme and HO on inflammation in mice were analyzed by monitoring the biodistribution of radiolabeled liposomes and leukocytes in conjunction with immunohistochemistry. Small liposomes accumulate in inflamed tissues by diffusion because of locally enhanced vascular permeability, whereas leukocytes actively migrate into inflammatory areas through specific adhesive interactions with the endothelium and chemotaxis. Exposure to heme resulted in a dramatic increase in liposome accumulation in the pancreas, but also intestines, liver, and spleen exhibited significantly increased vascular permeability. Similarly, intravenously administered heme caused an enhanced influx of radiolabeled leukocytes into these organs. Immunohistochemical analysis showed differential up-regulation of the adhesion molecules ICAM-1, P-selectin, and fibronectin in liver and pancreas in heme-treated animals. Heme-induced adhesive properties were accompanied by a massive influx of granulocytes into these inflamed tissues, suggesting an important contribution to the pathogenesis of inflammatory processes. Moreover, inhibition of HO activity exacerbated heme-induced granulocyte infiltration. Here it is demonstrated for the first time that heme induces increased vascular permeability, adhesion molecule expression, and leukocyte recruitment in vivo, whereas HO antagonizes heme-induced inflammation possibly through the down-modulation of adhesion molecules.

In vitro modulation of adhesion molecules, adhesion phenomena, and fluid phase endocytosis on human umbilical vein endothelial cells and brain-derived microvascular endothelium by IFN-beta 1a.

Administration of interferon-beta (IFN-beta) in multiple sclerosis (MS) patients provides clinical benefits, although its mechanism(s) of action are not completely understood. We addressed the issue of whether concentrations of IFN-beta1a close to those reached in the serum of treated MS patients could modulate either adhesion molecules or adhesion of peripheral blood mononuclear cells (PBMC) as well as fluid phase endocytosis (FPE) in human umbilical vein endothelial cells (HUVEC) and in brain-derived microvascular endothelial cells (HBMEC). Adhesion was assessed by flow cytometry, and FPE was evaluated by peroxidase uptake. In our study, 200 U/ml IFN-beta1a induced a reduction in adhesion of PBMC to HUVEC. The information reported herein may contribute to further elucidating some of the mechanisms of action of IFN-beta on vascular endothelium.

Feverfew Extracts and the Sesquiterpene Lactone Parthenolide Inhibit Intercellular Adhesion Molecule-1 Expression in Human Synovial Fibroblasts

Previous studies have shown that extracts of the aromatic herb feverfew (Tanacetum parthenium) and one of its bioactive components, parthenolide, have anti-inflammatory properties in vivo and in vitro. We examined both crude feverfew extracts and purified parthenolide for their ability to modulate adhesion molecule expression in human synovial fibroblasts. Pretreatment of synovial fibroblasts with either feverfew extracts or purified parthenolide could inhibit the expression of intercellular adhesion molecule-1 (ICAM-1) induced by the cytokines IL-1 (up to 95% suppression), TNF-α (up to 93% suppression), and, less strongly, interferon-γ (up to 39% suppression). Inhibition of ICAM-1 was dose and time dependent; as little as a 30-min pretreatment with feverfew resulted in inhibition of ICAM-1. The decrease in ICAM-1 expression was accompanied by a decrease in T-cell adhesion to the treated fibroblasts. Other herbal extracts with reported anti-inflammatory effects were similarly tested and did not decrease ICAM-1 expression. The modulation of adhesion molecule expression may be an additional mechanism by which feverfew mediates anti-inflammatory effects.

Reversibility of low VLA-4, and CXCR-4 expression on peripheral blood CD34+ cells

Molecular mechanisms leading to mobilisation and homing of hematopoietic progenitor cells and stem cells probably involve a modulation of adhesion molecules expressed on these cells. This modulation could be induced by interactions between chemokines and their receptors, such as SDF-1 and CXCR-4. In the present study, we compared VLA-4 (α4/β1), VLA-5 (α5/β1) and CXCR-4 expression on peripheral blood CD34+ cells during a 3-day liquid culture in 10 % FBS αMEM and murine stromal MS-5 cell supernatant (containing high levels of SDF-1). CD34+ cells were purified from leukapheresis products after G-CSF mobilisation and tested for co-expression of α4, α5, β1 chains and CXCR-4 by direct immuno-fluorescence. An increased expression of α4 and β1 but not α5 was seen from d1, particularly with MS-5 cell supernatant and in a lesser extent with 10 % FBS αMEM. Values were respectively 146 and 113 % for α4, 148 and 121 % for β1 and 99 and 105 % for α5 as compared to d0 expression. CXCR-4 expression was maximally increased on d2 particularly with 10 % FBS αMEM (308 % of d0 expression) but this increase was less clear with MS-5 cell supernatant (233 % of d0 expression). Maximal VLA-4 expression reached levels which are originally observed on bone marrow CD34+ cells while the low levels of α5 were not modified. We are now investigating the precise role of SDF-1 in the modulating activity contained in such culture media.