Ibuprofen inhibits pyrogen-dependent expression of VCAM-1 and ICAM-1 on human endothelial cells

Leukocyte adhesion and transmigration through the endothelial cell (EC) layer plays a crucial role in inflammation. IL-1 alpha and TNF alpha increase EC-adhesiveness for leukocytes by stimulating surface expression of ICAM-1 (intercellular adhesion molecule 1, CD54), VCAM-1 (vascular cell adhesion molecule 1, CD106) and E-selectin (CD62E). In this study, the effects of ibuprofen on IL-1 alpha and TNF alpha-induced expression of ICAM-1, VCAM-1 and E-selectin on cultured human umbilical vein EC (HUVEC) were analyzed. Exposure to IL-1 alpha or TNF alpha resulted in an increased expression of VCAM-1, ICAM-1, and E-selectin. Ibuprofen was identified as a potent inhibitor of IL-1 alpha and TNF alpha-induced surface expression of VCAM-1 and a less potent inhibitor of pyrogen-induced expression of ICAM-1, whereas no effect on E-selectin was found. The effects of ibuprofen on VCAM-1 expression were dose-dependent (IC50 [IL-1 alpha]: 0.5 mM; IC50 [TNF alpha]: 0.5 mM) and time-dependent with maximum responses observed after 18 h. Moreover, ibuprofen abrogated pyrogen-dependent adhesion of leukocytes to HUVEC. Ibuprofen also inhibited VCAM-1 mRNA expression in pyrogen activated EC. VCAM-1-downregulation on EC by ibuprofen may contribute to the anti-inflammatory actions of the drug.     

Chemokine production and adhesion molecule expression by neural cells exposed to IL-1, TNF alpha and interferon gamma

We investigated the effect of TNF alpha, IL-1alpha and IFN gamma on two neuroblastoma (NB) cell lines (SK-N-SH and SK-N-MC). These lines responded differentially to IL-1alpha, TNF alpha and IFN gamma for MCP-1 and IL-8 production and expression of the ICAM-1 and VCAM-1 adhesion molecules. None of the cytokines induced MCP-1 or IL-8 on SK-N-MC cells. Both chemokines were produced in response to IL-1alpha by SK-N-SH cells, while TNF alpha induced mainly MCP-1 production. Addition of IFN gamma decreased IL-8, but not MCP-1 production. These responses correlated with monocyte and neutrophil chemotactic activity in NB culture supernatants. This activity was neutralized by antibodies to IL-8 and MCP-1. The expression of ICAM-1 on SK-N-MC was up-regulated by TNF alpha or IFN gamma, while IL-1alpha also upregulated ICAM-1 on SK-N-SH cells. VCAM-1 expression on SK-N-SH was induced by IL-1alpha and TNF alpha and IFN gamma synergized with TNF alpha in this respect on both NB cell lines. These results suggest that mechanisms for chemokine production and VCAM-1 and ICAM-1 upregulation by inflammatory cytokines differ and IFN gamma, in conjunction with TNF alpha, stimulate neural cell responses (high MCP-1 and VCAM-1 and decreased IL-8) favouring mononuclear cell recruitment.     

Neutralization of TNF by the antibody cA2 reveals differential regulation of adhesion molecule expression on TNF-activated endothelial cells

Upregulation of adhesion proteins plays an important role in mediating inflammation. The induction of adhesive molecules has been well studied, but the reversibility of their expression has not been well characterized. A neutralizing anti-TNF monoclonal antibody (cA2) was used to study the down regulation of TNF-induced E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on cultured human umbilical vein endothelial cells (HUVECs). Addition of cA2 following TNF stimulation of HUVECs enhanced the rate of E-selectin and VCAM-1 down-regulation from the cell surface and also reduced steady state E-selectin and VCAM-1 mRNA levels. The cA2-mediated disappearance of E-selectin, but not VCAM-1 protein was microtubule and not microfilament dependent. Neutralization of TNF only slightly reduced ICAM-1 cell surface levels following initial TNF stimulation, suggesting a slower turnover of ICAM-1 compared to E-selectin and VCAM-1. Microtubule inhibition during TNF stimulation partially inhibited E-selectin, VCAM-1 and ICAM-1 mRNA upregulation. VCAM-1 and ICAM-1 cell surface expression were similarly partially inhibited, however, E-selectin levels were unaffected, presumably due to the dual, opposing effect of inhibiting protein expression and inhibiting internalization. Microfilament inhibition during protein induction specifically inhibited the maximal expression of VCAM-1 protein and mRNA, without affecting E-selectin or ICAM-1. These data support the notion that E-selectin, VCAM-1, and ICAM-1 expression are differentially regulated on HUVECs and suggest that TNF neutralizing therapies may be effective because of their ability to reduce the levels of pre-existing adhesion proteins.     

Rickettsia conorii infection enhances vascular cell adhesion molecule-1- and intercellular adhesion molecule-1-dependent mononuclear cell adherence to endothelial cells

Leukocyte adherence to the endothelium is an essential component of the inflammatory response during rickettsial infection. In vitro, Rickettsia conorii infection of endothelial cells enhances the expression of adhesive molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in a time- and dose-dependent manner. Rickettsial lipopolysaccharide does not seem to be involved, because polymyxin B does not reduce their expression. The intracellular presence of the organism and de novo host protein synthesis are required for expression of cell adhesive molecules, since rickettsial inactivation by formol and pretreatment of cells with cycloheximide inhibits an increase in expression. The contribution of interleukin-1alpha (IL-1alpha) to this endothelial adhesive phenotype was shown by inhibitory experiments 8 and 24 h after infection with IL-1 receptor antagonist and IL-1alpha blocking antibodies. Enhanced adherence of mononuclear cells to infected endothelial cells involved VCAM-1- and ICAM-1-dependent mechanisms at the late phase of the inflammatory response. This endothelial adhesive phenotype may constitute a key pathophysiologic mechanism in R. conorii-induced vascular injury.     

Preventing disability from work-related low-back pain. New evidence gives new hope--if we can just get all the players onside

Tumor necrosis factor (TNF) is a proinflammatory cytokine playing a central role in the expression of endothelial adhesion molecules required for the recruitment of inflammatory cells. Proliferative glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody is characterized by the recruitment of inflammatory cells in the glomerulus followed by capillary damage and crescent formation. The glomerular pathology may be due to a large extent to TNF induction. We therefore tested this hypothesis in TNF-deficient mice. Anti-GBM antibody administration in sensitized wild-type mice resulted in deposition of immune complexes, followed by increased intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression, as well as the influx of polymorphonuclear neutrophils (PMNs), lymphocytes, and macrophages. Distinct proteinuria preceded proliferative glomerulonephritis characterized by crescent formation. In the absence of TNF, the development of proteinuria was delayed and the formation of crescents was almost completely prevented. Although the deposition of immune complexes in glomeruli was comparable in both groups, the up-regulation of ICAM-1 and VCAM-1, as well as the influx of PMNs and lymphocytes, but not of monocytes, was dramatically reduced in TNF-deficient mice. Therefore, we conclude that TNF plays a key role in the recruitment of inflammatory cells and in the subsequent development of proliferative glomerulonephritis.     

Brown tumor of the mandible

OBJECTIVE: To investigate the inhibitory effect of IL-10 on inflammatory reaction in rat mesangial cells (rMC). METHODS: Cell proliferation was tested by 3H-thymidine uptake and absolute cell counts. The production of IL-1 and TNF alpha by rMC was assessed by bioactivity assay and their gene expression by Northern blot hybridization. The expression of intercellular adhesion molecule-1 (ICAM-1) on rMC was determined by ELISA. RESULTS: IL-10 (25 ng/ml) inhibited 5% FCS and IL-1 induced cell proliferation by 39% and 52% respectively. It also suppressed the production of IL-1 and TNF alpha bioactivity by rMC by 48% and 68%, which was consistent with the decline of IL-1 and TNF alpha gene expression. The IL-1-induced expression of ICAM-1 on surface of rMC was attenuated by IL-10 treatment. CONCLUSION: Our data suggest that IL-10 may be an inhibitory cytokine in regulation of inflammatory reaction in glomerular mesangial cells.     

Retinoic acid receptors regulate expression of retinoic acid 4-hydroxylase that specifically inactivates all-trans retinoic acid in human keratinocyte HaCaT cells

Among oxysterols oxidized at C7 (7alpha-, 7beta-hydroxycholesterol, and 7-ketocholesterol), 7beta-hydroxycholesterol and 7-ketocholesterol involved in the cytotoxicity of oxidized low density lipoproteins (LDL) are potent inducers of apoptosis. Here, we asked whether all oxysterols oxidized at C7 were able to trigger apoptosis, to stimulate interleukin (IL)-Ibeta and/or tumor necrosis factor (TNF)-alpha secretion, and to enhance adhesion molecule expression (intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin) on human umbilical venous endothelial cells (HUVECs). Only 7beta-hydroxycholesterol and 7-ketocholesterol were potent inducers of apoptosis and of IL-1beta secretion. TNF-alpha secretion was never detected. Depending on the oxysterol considered, various levels of ICAM-1, VCAM-1 and E-selectin expression were observed. So, oxysterols oxidized at C7 differently injure and activate HUVECs, and the alpha- or beta-hydroxyl radical position plays a key role in apoptosis and IL-1beta secretion.     

Direct cell/cell contact with stimulated T lymphocytes induces the expression of cell adhesion molecules and cytokines by human brain microvascular endothelial cells

Upon inflammation, stimulated, but not resting T lymphocytes cross the blood-brain barrier and migrate into the central nervous system. This study shows that direct contact between stimulated T lymphocytes and human brain microvascular endothelial cells (HB-MVEC) induces phenotypic and functional changes on the latter cells. Plasma membranes isolated from stimulated T lymphocytes (S-PM) up-regulated the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin on isolated HB-MVEC. In addition, HB-MVEC activated by S-PM secreted interleukin (IL)-6 and IL-8. The levels of ICAM-1, E-selectin, IL-6, and IL-8 expressed in S-PM-activated HB-MVEC were similar to those observed with 1000 U/ml tumor necrosis factor (TNF). In contrast, VCAM-1 expression was 15% of that induced by TNF. Inhibitors of TNF diminished (< or = 45%), but did not abolish the expression of cell adhesion molecules and IL-6 induced by S-PM, IL-8 production being insignificantly affected (< or = 10%). This suggests that membrane-associated TNF was partially involved in HB-MVEC activation. The present study demonstrates that stimulated T lymphocytes are able to activate HB-MVEC upon direct cell contact. This novel mechanism of inducing the expression of cell adhesion molecules may prompt the initial adhesion of stimulated T lymphocytes to brain endothelium.     

The pre- and postsynaptic mechanisms of the involvement of the serotonin of the amygdaloid body in the reproduction of the conditioned passive avoidance reaction in rats

A previous study reported that intercellular adhesion molecule-1 (ICAM-1) expression by human vascular endothelial cells (HUVEC) is augmented by intracellular signal transmission mainly through the protein kinase C (PKC) system stimulated by TXA2 receptors. In the present study, we show that a TXA2 receptor agonist, U46619, augments the expression of not only ICAM-1, but also vascular cell adhesion molecule-1 (VCAM-1) or endothelial leucocyte adhesion molecule-1 (ELAM-1) in HUVEC both at protein and mRNA levels. Pretreatment with SQ29,548 (a TXA2 receptor antagonist) or PKC inhibitors greatly diminished the extent of U46619-induced mRNA accumulation and surface expression of the adhesion molecules. An inhibitor of nuclear factor kappaB (NF-kappaB) activation, PDTC, diminishes U46619-induced VCAM-1 mRNA accumulation. NAC, which inhibits NF-kappaB and activation protein 1 (AP-1) binding activity, inhibits the expression of ICAM-1 or ELAM-1 at protein and mRNA levels. These findings suggest that ICAM-1 or ELAM-1 expression of HUVEC stimulated via TXA2 receptors is augmented by induction of NF-kappaB and AP-1 binding activity through the PKC system, and that VCAM-1 expression is augmented by induction of NF-kappaB binding activity.     

Differential reactivity of brain microvascular endothelial cells to TNF reflects the genetic susceptibility to cerebral malaria

Upon infection with Plasmodium berghei ANKA (PbA), various inbred strains of mice exhibit different susceptibility to the development of cerebral malaria (CM). Tumor necrosis factor-alpha (TNF) and interferon-gamma (IFN-gamma) have been shown to be crucial mediators in the pathogenesis of this neurovascular complication. Brain microvascular endothelial cells (MVEC) represent an important target of both cytokines. In the present study, we show that brain MVEC purified from CM-susceptible (CM-S) CBA/J mice and CM-resistant (CM-R) BALB/c mice exhibit a different sensitivity to TNF. CBA/J brain MVEC displayed a higher capacity to produce IL-6 and to up-regulate intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in response to TNF than BALB/c brain MVEC. In contrast, no difference was found in the induction of E-selectin after TNF challenge. CM-S brain MVEC were also significantly more sensitive to TNF-induced lysis. This differential reactivity to TNF was further substantiated by comparing TNF receptor expression on CM-S and CM-R brain MVEC. Although the constitutive expression of TNF receptors was comparable on cells from the two origins, TNF induced an up-regulation of both p55 and p75 TNF receptors in CM-S, but not in CM-R brain MVEC. A similar regulation was found at the level of TNF receptor mRNA, but not for receptor shedding. Although a protein kinase C inhibitor blocked the response to TNF in both the brain MVEC, an inhibitor of protein kinase A selectively abolished the response to TNF in CM-R, but not CM-S brain MVEC, suggesting a differential protein kinase involvement in TNF-induced activation of CM-S and CM-R brain MVEC. These results indicate that brain MVEC purified from CM-S and CM-R mice exhibit distinctive sensitivity to TNF This difference may be partly due to a differential regulation of TNF receptors and via distinct protein kinase pathways.     

Antimutagenic activity of extracts from Japanese eggplant

There is increasing evidence that Schwann cells play an important role in the pathogenesis of autoimmune inflammatory peripheral nerve disease. Schwann cells have been reported to express major histocompatibility complex class I and II (MHC I and II) and intercellular adhesion molecule-1 (ICAM-1), and to produce interleukin-1 (IL-1), prostaglandin E2 and thromboxane A2. In this study we investigated freshly dissociated neonatal Lewis rat Schwann cells and a SV40 transfected neonatal rat Schwann cell line (Schwann cell line) for production of mRNA for the immunomodulatory cytokines IL-2, IL-4, IL-6, IL-10, interferon-gamma (IFN gamma), and tumor necrosis factor-alpha (TNF alpha) employing RT-PCR. Primary Schwann cells and Schwann cell line were examined following IFN gamma stimulation and were found to express TNF alpha and IL-6 mRNA. These results further support a role for Schwann cell participation in inflammatory responses within the peripheral nervous system (PNS).