Upregulation Of ICAM-1 Research Articles

Sequential Expression of Adhesion and Costimulatory Molecules in Graft-versus-Host Disease Target Organs after Murine Bone Marrow Transplantation across Minor Histocompatibility Antigen Barriers

Graft-versus-host disease (GVHD) is a potentially fatal complication after allogeneic bone marrow transplantation. However, few data exist thus far on the molecular signals governing leukocyte trafficking during the disease. We therefore investigated the sequential pattern of distinct adhesion, costimulatory, and apoptosis-related molecules in GVHD organs (ileum, colon, skin, and liver) after transplantation across minor histocompatibility barriers (B10.D2 --> BALB/c, both H-2d). To distinguish changes induced by the conditioning regimen from effects achieved by allogeneic cell transfer, syngeneic transplant recipients (BALB/c --> BALB/c) and irradiated nontransplanted mice were added as controls. Irradiation upregulated the expression of vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-l, and B7-2 in ileum, as well as VCAM-1 and B7-2 in colon, on day 3 in all animals. Whereas in syngeneic mice these effects were reversed from day 9 on, allogeneic recipients showed further upregulation of VCAM-1, ICAM-1, B7-1, and B7-2 in these organs on day 22, when GVHD became clinically evident. Infiltration of CD4+ and CD8+ donor T cells was noted on day 9 in skin and liver and on day 22 in ileum and colon. Surprisingly, the expression of several other adhesion molecules, such as ICAM-2, platelet-endothelial cell adhesion molecule 1, E-selectin, and mucosal addressin cell adhesion molecule 1, did not change. Proapoptotic and antiapoptotic markers were balanced in GVHD organs with the exception of spleen, in which a preferential expression of the proapoptotic Bax could be noted. Our results indicate that irradiation-induced upregulation of VCAM-1, ICAM-1, and B7-2 provides early costimulatory signals to incoming donor T cells in the intestine, followed by a cascade of proinflammatory signals in other organs once the alloresponse is established.

Thrombin, TNF-α, and LPS exert overlapping but nonidentical effects on gene expression in endothelial cells and vascular smooth muscle cells

Thrombin, TNF-alpha, and LPS have each been implicated in endothelial cell and vascular smooth muscle cell (VSMC) activation. We wanted to test the hypothesis that these three agonists display mediator and/or cell type-specific properties. The addition of thrombin to human pulmonary artery endothelial cells resulted in an upregulation of PDGF-A, tissue factor (TF), ICAM-1, and urokinase-type plasminogen activator (u-PA), whereas TNF-alpha and LPS failed to induce PDGF-A. These effects were mimicked by protease-activated receptor-1 activation. In VSMC, thrombin induced expression of TF and PDGF-A but failed to consistently induce ICAM-1 or u-PA expression. In contrast, TNF-alpha and LPS increased expression of all four genes in this cell type. Inhibitor studies in endothelial cells demonstrated a critical role for PKC in mediating thrombin, TNF-alpha, and LPS induction of ICAM-1, TF, and u-PA and for p38 MAPK in mediating thrombin, TNF-alpha, and LPS induction of TF. Taken together, these results suggest that inflammatory mediators engage distinct signaling pathways and expression profiles in endothelial cells and VSMC. The data support the notion that endothelial cell activation is not an all-or-nothing phenomenon but rather is dependent on the nature of the extracellular mediator.

Expression of adhesion molecules in lungs of mice infected with Paracoccidioides brasiliensis conidia

In infected tissues, leukocyte recruitment is mediated by interactions between adhesion molecules, expressed on activated vascular endothelial cells, and ligands present on circulating cells. We evaluated the inflammatory response and the expression of cellular adhesion molecules (ICAM-1, VCAM-1, CD18, LFA-1 and Mac-1) in lungs of BALB/c mice infected with Paracoccidioides brasiliensis conidia. When compared with uninfected animals, infected mice had a significant increase in the inflammatory response during the first 4 days, peaking 2–3 days post-challenge, 40.3% vs. 0.0% and 41.8% vs. 0.7%, respectively. This inflammatory infiltrate was composed mainly of neutrophils and macrophages with a few eosinophils and lymphocytes. An increase in the intensity of immunofluorescence (IF) for ICAM-1 was also observed during days 1–4. ICAM-1 was present in bronchiolar epithelium, type II pneumocytes, and macrophages, as well as on vascular endothelium. The control animals presented ICAM-1 constitutively. In infected mice, VCAM-1 was only observed on vascular endothelium during the first 2 days, with some macrophages expressing this molecule throughout the study periods. CD18 and Mac-1 but not LFA-1 were expressed with a high intensity on neutrophils and macrophages present in the inflammatory infiltrate. In addition, we observed a significant decrease in Colony forming units (CFUs) after the first 2 days post-challenge. These findings suggest that during these early stages, up-regulation of ICAM-1, VCAM-1, CD18 and Mac-1 expression occurs, participating in the inflammatory process and as such, in the pathogenesis of paracoccidioidomycosis (PCM).

Regulation of the soluble receptor for TNFα on conjunctival epithelial cells and correlation with ICAM-1 upregulation by TNFα and IgE-activated conjunctival mast cells

Regulation of the soluble receptor for TNFα on conjunctival epithelial cells and correlation with ICAM-1 upregulation by TNFα and IgE-activated conjunctival mast cells

Involvement of Toll-like Receptor 3 in the Immune Response of Lung Epithelial Cells to Double-stranded RNA and Influenza A Virus

Influenza A is a highly contagious single-stranded RNA virus that infects both the upper and lower respiratory tracts of humans. The host innate immune Toll-like receptor (TLR) 3 was shown previously in cells of myeloid origin to recognize the viral replicative, intermediate double-stranded RNA (dsRNA). Thus, dsRNA may be critical for the outcome of the infection. Here we first compared the activation triggered by either influenza A virus or dsRNA in pulmonary epithelial cells. We established that TLR3 is constitutively expressed in human alveolar and bronchial epithelial cells, and we describe its intracellular localization. Expression of TLR3 was positively regulated by the influenza A virus and by dsRNA but not by other inflammatory mediators, including bacterial lipopolysaccharide, the cytokines tumor necrosis factor-alpha and interleukin (IL)-1beta, and the protein kinase C activator phorbol 12-myristate 13-acetate. We also demonstrated that TLR3 contributes directly to the immune response of respiratory epithelial cells to influenza A virus and dsRNA, and we propose a molecular mechanism by which these stimuli induce epithelial cell activation. This model involves mitogen-activated protein kinases, phosphatidylinositol 3-kinase/Akt signaling, and the TLR3-associated adaptor molecule TRIF but not MyD88-dependent activation of the transcription factors NF-kappaB or interferon regulatory factor/interferon-sensitive response-element pathways. Ultimately, this signal transduction elicits an epithelial response that includes the secretion of the cytokines IL-8, IL-6, RANTES (regulated on activation normal T cell expressed and secreted), and interferon-beta and the up-regulation of the major adhesion molecule ICAM-1.

FK778, a novel immunosuppressive agent, reduces early adhesion molecule up-regulation and prolongs cardiac allograft survival*

The adhesion molecules, P-selectin, ICAM-1, and VCAM-1 are important mediators of T-cell adhesion and T-cell co-stimulation. We investigated the effect of the malononitrilamide FK778 on cardiac allograft survival, acute allograft rejection, and adhesion molecule up-regulation in a heterotopic, cardiac transplantation model. Rats received low- or high-dose FK778 or no treatment. Grafts were harvested on the fifth postoperative day for histologic examinations. To assess allograft survival, recipients were treated for a maximum of 10 days and grafts were harvested after cessation of the contractile activity. FK778 low dose showed a mild but significant decrease in mononuclear infiltration but failed to markedly reduce histologic rejection, adhesion molecule up-regulation, or to prolong allograft survival. However, high-dose FK778 treatment significantly reduced early up-regulation of P-selectin, ICAM-1, and VCAM-1, abolished infiltration, reduced histologic rejection and resulted in prolonged cardiac allograft survival. Therefore, FK778 is a novel, highly desirable immunosuppressive drug for transplantation medicine.

Ox-LDL plays dual effect in modulating expression of inflammatory molecles through LOX-1 pathway in human umbilical vein endothelial cells

Lectin-like oxidized low-density lipoprotein receptor1 (LOX-1) has been recognized to be the major endothelial receptor for oxidized low-density lipoprotein (ox-LDL). Ox-LDL has been reported to induce the expression of inflammatory adhesive molecules from vascular endothelium. However, the mechanism of this action has not been fully elucidated. Peroxisome proliferation-activated receptor-gamma (PPARgamma) regulates the expression of inflammatory adhesive molecules. The present study was carried out to investigate the role of LOX-1-PPARgamma pathway in regulating expression of adhesion molecules, ICAM-1 and E-selectin in HUVECs. Ox-LDL increased the expression of ICAM-1 and E-selectin in a concentration (10-50 microg/ml)--and time (6-36 hours)--dependent manners. These effects were significantly inhibited by pretreatment of HUVECs with polyinosonic acid or carrageenan. Preincubating HUVECs with 15d-PGJ2 attenuated the expression of ICAM-1 and E-selectin in response to ox-LDL, although ox-LDL stimulated the expression of PPARgamma. Upregulation of ICAM-1 and E-selectin mediated by ox-LDL were inhibited more significantly by the combination of 15d-PGJ2 and polyinosonic acid as compared to either 15d-PGJ2 or polyinosonic acid alone. The results suggested that ox-LDL through its receptor LOX-1 promotes pro-inflammation response by increasing expression of ICAM-1 and E-selectin, simultaneously activates PPARgamma triggering cellular anti-inflammation response in protection from the inflammation lesions in HUVECs.

Regulation of Soluble Receptor for TNFα on Conjunctival Epithelial Cells and Correlation with ICAM-1 Upregulation by TNFα and IGE-Activated Conjunctival Mast Cells

The influences of Ge addition on crystallization kinetics, microstructure and high-temperature magnetic property of nanocrystalline FeAlSiBCuNbGe alloy have been investigated. The results showed that doping a small amount of Ge into Fe72.7Al0.8Si17.5B5Cu1Nb3 alloy can lower the activation energy and therefore decrease the glass forming ability. The primary crystalline temperature Tx1 and secondary crystallization temperature Tx2 were slightly decreased. But the addition of Ge enhances the Curie temperature of amorphous phase, which significantly improved high-temperature magnetic softness. Average grain sizes were increased and thickness of intergranular amorphous layer was decreased due to the addition of Ge to alloys. The optimum annealing temperature for Fe72.7Al0.8Si17.5B5Cu1Nb2.6Ge0.4 alloy was obtained at 843 K. The reason for the enhancement in high-temperature magnetic softness was systematically analyzed in terms of the evolution of microstructure.

Role of endogenous and exogenous ligands for the peroxisome proliferators activated receptors alpha (PPAR-α) in the development of inflammatory bowel disease in mice

The peroxisome proliferator-activated receptor-α (PPAR-α) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid and thyroid hormone receptors. The aim of the present study was to examine the effects of endogenous and exogenous PPAR-α ligand on the development of experimental colitis. To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS). When compared to DNBS-treated PPAR-α wild-type (WT) mice, DNBS-treated PPAR-α knockout mice (PPAR-αKO) mice experienced a higher rate of the extent and severity of the histological signs of colon injury. After administration of DNBS PPAR-αWT mice experienced hemorrhagic diarrhea, weight loss and large areas of necrosis in the mucosa of the colon were also observed. Neutrophil infiltration was associated with upregulation of ICAM-1. Immunohistochemistry for nitrotyrosine showed an intense staining in the inflamed colon. Absence of a functional PPAR-α gene in PPAR-αKO mice resulted in a significant augmentation of all the above-described parameters. On the contrary, the treatment of PPAR-αWT with Wy-14643 (1 mg/kg daily i.p) significantly reduced: (i) the degree of hemorrhagic diarrhea and weight loss, (ii) the degree of colon injury, (iii) the rise in MPO activity (mucosa), (iv) the increase in staining (immunohistochemistry) for nitrotyrosine, as well as (v) the upregulation of ICAM-1 caused by DNBS in the colon. In order to elucidate whether the protective effects of Wy-14643 is related to activation of the PPAR-α receptor, we also investigated the effect the of Wy-14643 treatment on PPAR-α-deficient mice. The absence of the PPAR-α receptor significantly abolished the protective effect of the PPAR-α agonist against DNBS-induced colitis. Thus, endogenous and exogenous PPAR-α ligands reduce the degree of colitis caused by DNBS. We propose that PPAR-α ligand may be useful in the treatment of inflammatory bowel disease.

Effects of the Indazolylpyrimidine GW786034 on Angiogenesis and MM Cell Growth: Therapeutic Implications.

Vascular endothelial growth factor (VEGF) and its receptors play an important role in the pathogenesis of multiple myeloma (MM). Specifically, VEGF, which is present in the MM bone marrow (BM) microenvironment, induces neovascularization; triggers tumor cell growth, survival, and migration; inhibits dendritic cell maturation; and induces osteoclastogenesis. Therefore, the VEGF receptor provides a potential novel therapeutic target in MM. Previous studies showed that GW654652, a pan VEGFR inhibitor, inhibits growth and migration of MM tumor cells (Podar et al. Blood . 2004; 103:3473–3479.). Here we describe the effects of GW786034, a derivative of GW654652, on MM cells to support its potential clinical evaluation in MM patients. GW786034 inhibits VEGF- triggered Flt-1 phosphorylation and activation of downstream signaling molecules, induces concentration-dependent MM cell and HUVEC apoptosis, and inhibits VEGF- triggered MM cell migration. Specifically, GW786034 induces cleavage of caspase-8 and PARP, but not caspase-9, and induces downregulation of the pro-apoptotic molecules survivin, cIAP1, 2, and Mcl-1. Furthermore, GW786034 decreases proliferation of MM cells induced by their adhesion to BMSCs, and inhibits VEGF-induced upregulation of ICAM-1 and VCAM-1, thereby abrogating their adhesion to HUVECs. Consistent with these results, GW786034 inhibited both tubuli formation and accumulation of tumor cells at vascular branching points in a Matrigel tube forming assay. Finally, GW786034 sensitizes both MM cells alone and tumor cells bound to BMSCs or HUVECs to melphalan and bortezomib. Taken together, these studies support clinical evaluations of GW786034 either alone or in combination with other agents in MM patients.

The Role of B Cell-Mediated T Cell Costimulation in the Efficacy of the T Cell Retargeting Bispecific Antibody BIS20x3

In this study, we investigated the role of the naturally occurring B cell-mediated T cell costimulation in the antitumor efficacy of the bispecific Ab BIS20x3. BIS20x3 has a dual specificity for both CD20 and CD3 and has previously been shown to effectively direct the lytic potential of cytolytic T cells toward malignant, CD20(+) B cells. BIS20x3 instigated T cell-B cell interaction caused a dose-dependent activation of T cells that was 30 times stronger when compared with T cell activation induced by monovalent anti-CD3 Abs. The activation of T cells by BIS20x3 and B cells appeared functional and resulted in the rapid induction of high lytic potential in freshly isolated peripheral T cells. BIS20x3-mediated T cell-B cell interaction resulted in a significant up-regulation of ICAM-1 on B cells and the activation of T cells was found to be dependent on the interaction of ICAM-1 with LFA-1 and trans-activation by the NF-kappaB pathway. Also, the lytic potential of freshly isolated T cells activated via BIS20x3 appeared to be dependent on NF-kappaB signaling in the target B cells. Interestingly, the costimulatory signaling effects described in this study appeared specifically related to the targeting against CD20 because targeting against CD19, by a CD3xCD19-directed bispecific Ab, was significantly less effective in inducing T cell activation and T cell-mediated B cell lysis. Together these results demonstrate that the malignant B cells actively contribute to their own demise upon CD20-directed bispecific Ab-mediated T cell targeting.

Are Anti–Oxidized Low-Density Lipoprotein Antibodies Pathogenic or Protective?

Despite a recent decline, atherosclerosis remains the most common cause of death in the Western world. The disease course of atherosclerosis is characterized by its chronicity, with progression in its initial stages being particularly insidious. Chronic inflammation is the pathological hallmark of atherosclerosis,1–4 and inflammatory processes are instrumental at all stages of this disease. Even before the development of detectable intimal lesions, the expression pattern of the endothelium has been shown to be inflammatory in nature, conforming to the response-to-injury hypothesis first postulated by the late Russell Ross.5 Thus, in lesion-prone sites of the arterial tree, the endothelial expression of adhesion molecules is upregulated, reflecting endothelial dysfunction secondary to unfavorable blood rheology6 and/or hypercholesterolemia.7–9 Atherosclerosis is known today to be associated with the burden of infection as well.10 The presence of infectious/inflammatory pathogeneses raises the autoimmune aspect of the condition.11–14 Anti–oxidized LDL (oxLDL) antibodies are exceptional among the autoantibodies prevalent in atherosclerosis: on the one hand, a correlation was found between the existence and titers of anti-oxLDL antibodies and the extent of atherosclerosis and cardiovascular disease (CVD) (Table 1). On the other hand, experimental data indicate that anti-oxLDL antibodies may be protective. View this table: TABLE 1. Correlation Between Titers of Anti-oxLDL Abs and Atherosclerosis and CVD oxLDL frequently presents in the sera of patients with autoimmune conditions, acute coronary syndrome, or stable coronary artery disease (CAD).15–18 OxLDL has been associated with both subclinical atherosclerosis and inflammatory variables.19 A large amount of oxLDL accumulates in atherosclerotic plaques,20–22 and the serum concentrations of circulating oxLDL may correlate with the severity of CAD23 and acute coronary syndrome.24 OxLDL seems to be an immunogenic molecule that stimulates the induction of anti-oxLDL antibodies. Thus, it is not surprising that an association was found between the presence …

WY 14643, a potent exogenous PPAR-alpha ligand, reduces intestinal injury associated with splanchnic artery occlusion shock.

The peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid, and thyroid hormone receptors. WY 14643 is a potent PPAR-alpha ligand that modulates the transcription of target genes. The aim of this study was to investigate the effect of WY 14643 on the tissue injury caused by ischemia-reperfusion (I/R) of the gut. I/R injury of the intestine was caused by clamping both the superior mesenteric artery and the celiac trunk for 45 min, followed by release of the clamp, allowing reperfusion for 2 h or 4 h. This procedure results in splanchnic artery occlusion (SAO) shock. Rats subjected to SAO developed a significant fall in mean arterial blood pressure, and only 20% of the animals survived for the entire 4-h reperfusion period. Surviving animals were sacrificed for histological examination and biochemical studies. Rats subjected to SAO displayed a significant increase in tissue myeloperoxidase (MPO) activity, significant increases in plasma tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta levels, and marked injury to the distal ileum. Increased immunoreactivity to nitrotyrosine and polyadenosine diphosphate [ADP]-ribose (PAR) was observed in the ileum of rats subjected to SAO. Staining of sections of the ileum obtained from SAO rats with anti-intercellular adhesion molecule (ICAM-1) antibody or with anti-P-selectin antibody resulted in diffuse staining. Administration of WY 14643 (1 mg/kg i.v.) 30 min before the onset of gut ischemia significantly reduced the (a) fall in mean arterial blood pressure, (b) mortality rate, (c) infiltration of the reperfused intestine with polymorphonuclear neutrophils (MPO activity), (d) production of proinflammatory cytokines (TNF-alpha and IL-1beta), and (e) histological evidence of gut injury. Administration of WY 14643 also markedly reduced the nitrotyrosine formation, poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) activation, up-regulation of ICAM-1, and expression of P-selectin during reperfusion. These results demonstrate that the PPAR-alpha agonist WY 14643 significantly reduces I/R injury of the intestine.

Effect of ligustrazine on ischemia-reperfusion injury in murine kidney

Introduction Ischemia-reperfusion (I/R) injury is unavoidable in cadaveric renal transplantation. It contributes to acute rejection and chronic allograft dysfunction. Studies have shown that Ligustrazine, a purified and chemically identified component of a Chinese herbal remedy, is a potent blocker of vasoconstriction and has strong effects to scavenge oxygen free radicals. Since warm I/R is potentially more damaging than cold storage, we investigated the possible protective effect of Ligustrazine on warm I/R in mice. Methods Unilaterally nephrectomized C57BL/6 male mice were subjected to 50 minutes of left renal ischemia. Group I were sham-operated animals; group II, nontreated animals (saline, iP 30 minutes before I/R); and group III, Ligustrazine-treated animals (80 mg/kg, iP 30 minutes before I/R). Mice were sacrificed 24 hours postreperfusion. Serum creatinine, blood urea nitrogen, kidney malondialdehyde (MDA)level, and superoxide dismutase (SOD) were determined as well as examining the kidneys histologically with immunohistochemistry for Bcl-2, and ICAM-1. Results I/R produced a six fold increase in creatinine and urea nitrogen levels in group II. Ligustrazine halved the increase, as well as attenuated the necrosis and apoptosis in the tubules ( P < .01). Ligustrazine decreased MDA levels and ameliorated the down-regulation of SOD activity. Bcl-2 was up-regulated following I/R, especially in the Ligustrazine-treated group ( P < .01). The up-regulation of ICAM-1 was greatly diminished by Ligustrazine ( P < .01). Conclusion These findings suggest that Ligustrazine reduces the renal dysfunction associated with warm I/R of the kidney.

Inhibition of ICAM-1/LFA-1 interaction prevents allograft tolerance induced by anti-CD45RB

Abstract Introduction: Long-term allograft tolerance may be established by elimination of peripheral graft-reactive cell, by the induction of regulatory cells, or by induced ignorance through alteration of lymphocyte trafficking. We have investigated the contribution of the intracellular adhesion molecules ICAM-1/LFA-1 to tolerance induced by anti-CD45RB. Methods: Cardiac allografts from C3H mice were transplanted to either wild-type or ICAM-deficient C57BL/6 mice. Recipients were untreated, treated with anti-CD45RB mAb (100ug ip days 0, 1, 3, 5, and 7), or treated with a combination of anti-CD45RB and anti ICAM-1 or anti-LFA1 (50ug ip x5). Immunophenotyping of B cells by flow cytometry was performed after exposure of mice to alloantigen and anti-CD45RB. Results: Exposure of lymphocytes in vivo to anti-CD45RB and alloantigen induces upregulation of ICAM-1 on B cells. Although treatment with anti-CD45RB uniformly establishes permanent acceptance of C3H allografts (MST > 100days, n = 14), coadministration of either anti-ICAM-1 or anti-LFA-1 prevents tolerance induction (MST = 28.25 ± 2.96 and 14 ± 3.11 days, respectively). Neither anti-ICAM-1 or anti-LFA-1 therapy alone induced permanent allograft survival despite modest prolongation of survival. Treatment of genetically ICAM deficient B6 animals with anti-CD45RB also failed to induce tolerance (MST = 23.66 ± 3.57 days). Conclusions: These data suggest the involvement of ICAM-1/LFA-1 interactions during tolerance induction mediated by anti-CD45RB. Whether this effect is mediated by inter- or intracellular signaling through these molecules or by alterations of lymphocyte trafficking patterns is under investigation.

CCR2 -/- knockout mice revascularize normally in response to severe hindlimb ischemia

Monocyte chemoattractant protein-1 (MCP-1) is reported to stimulate ischemia-induced arteriogenesis (collateral artery development) by recruiting monocytes and macrophages into areas of active arteriogenesis. To determine whether the MCP-1-mediated response occurs through its receptor, CC-chemokine receptor 2 (CCR2), we induced hindlimb ischemia in mice lacking the receptor for MCP-1 (CCR2 -/- ) and measured limb blood flow recovery, collateral artery development, and monocyte and macrophage recruitment. Hindlimb ischemia was induced by excising the left femoral artery in CCR2 -/- and wild-type mice. Hindlimb blood flow recovery, as measured using laser Doppler perfusion imaging, was equivalent in both groups ( P = .78 for foot and P = 0.38 for calf). Collateral artery development, as measured by angiography at postoperative day 14 and 31, likewise did not differ between the 2 groups ( P = .46 and P = .67). Counts of monocytes and macrophages in calf and thigh muscle sections of mice sacrificed on postoperative day 7 revealed that although CCR2 -/- mice recruited 44% fewer monocytes and macrophages to areas of ischemia in the calf, they recruited similar numbers of monocytes and macrophages to areas of active arteriogenesis in the thigh. Intercellular adhesion molecule-1 and MCP-1 mRNA levels were higher in the thigh muscle of CCR2 -/- mice than in wild-type mice (5.5-fold and 42.3-fold induction operated to unoperated vs 2.6-fold and 6.1-fold induction operated to unoperated, respectively). Blood flow recovery, arteriogenesis, and monocyte and macrophage recruitment to the thigh was normal in CCR2 -/- mice. However, monocyte and macrophage recruitment to the ischemic calf was diminished in CCR2 -/- mice. Our results show that MCP-1 signaling through CCR2 is not required for physiologic arteriogenesis in response to severe hindlimb ischemia. ICAM-1 upregulation may substitute for MCP-1 signaling through CCR2 in order to allow normal arteriogenesis in CCR2 -/- mice.

Influence of proinflammatory cytokines on the adhesion of human colon carcinoma cells to lung microvascular endothelium.

In this experimental study, the influence of surgery-induced proinflammatory cytokines on tumor recurrence in the lung was investigated. A reproducible human in vitro assay was developed to study the adhesion of HT29 colon carcinoma cells to monolayers of microvascular endothelial cells of the lung (HMVECs-L) or human umbilical venous endothelial cells (HUVECs). Preincubation of HMVECs-L with maximally active concentrations of IL-1beta and TNF-alpha, but not with IL-6, resulted in at least 250% adhesion compared to control adhesion (p <or= 0.01). The effect of IL-1beta and TNF-alpha was concentration- and time-dependent. Comparable results were found for HUVECs. Tumor cell adhesion was not increased after preincubation of HT29 with TNF-alpha. Enzyme immunoassays of cytokine-preincubated HUVECs and HMVECs-L showed concentration- and time-dependent upregulation of E-selectin, ICAM-1 and VCAM-1 expression. In addition, LFA-1 and VLA-4 were only expressed on HMVECs-L, creating more binding possibilities for HMVECs-L compared to HUVECs. Inhibition assays with anti-E-selectin monoclonal antibody significantly decreased tumor cell adhesion to HUVECs; however, it did not affect tumor cell adhesion to HMVECs-L. Furthermore, anti-ICAM-1 and anti-VCAM-1 antibodies did not affect adhesion. Our results prove IL-1beta and TNF-alpha promote tumor cell adhesion to HMVECs-L in vitro and may therefore account for enhanced tumor recurrence in the lung seen after major surgical trauma. The adhesion of HT29 to HUVEC is inhibitable by E-selectin antibodies, whereas the adhesion to HMVEC-L is not inhibitable by these antibodies. Probably not one but a complex of adhesion molecules is responsible for enhanced adhesion to HMVECs-L.

Membrane-bound ICAM-1 is upregulated by trypsin and contributes to leukocyte migration in acute pancreatitis.

In acute pancreatitis, ICAM-1 is upregulated in various organs and contributes to the development of organ injury. To investigate the effects of pancreatic proteases on ICAM-1 expression and their role in the early process of leukocyte migration, human umbilical vein endothelial cells (HUVECs) were incubated with serum subjected to limited trypsin digestion and Wistar rats were injected with trypsin. Significant upregulation of membrane-bound ICAM-1 was seen on HUVECs incubated with trypsinated serum. Likewise, soluble ICAM-1 increased in the supernatant of HUVECs. Changes of membrane-bound ICAM-1 and soluble ICAM-1 were maximal with high concentrations of trypsin. HUVECs incubated with TNF-alpha (positive control) showed similar changes. In the pancreas and lungs of animals infused with trypsin, ICAM-1 and leukocyte sequestration were increased compared with controls. Reflecting the relevance of protease-induced ICAM-1 expression in leukocyte migration, leukocyte-endothelium interaction, as assessed by intravital microscopy, was markedly increased by trypsin. Inhibition of ICAM-1 ameliorated these changes significantly. In conclusion, trypsinated serum induces the upregulation of both membrane-bound ICAM-1 on endothelial cells and soluble ICAM-1. These changes contribute to the early steps of leukocyte migration in acute pancreatitis. The role of soluble ICAM-1 remains to be investigated.

Immunopathology of vesicular cutaneous lupus erythematosus in the rough collie and Shetland sheepdog: a canine homologue of subacute cutaneous lupus erythematosus in humans.

Clinical and histological features of an erosive disease in the rough collie and Shetland sheepdog are most consistent with a vesicular variant of cutaneous lupus erythematosus (VCLE). This paper reports the immunopathological findings of canine VCLE using samples from 17 affected dogs. Lesional skin sections were stained with monoclonal antibodies specific for CD3 (11 dogs) or a panel of monoclonal antibodies specific for leukocyte antigens (two dogs). Apoptotic cells were detected using the TUNEL method in 12 cases. Direct (14 dogs) and indirect immunofluorescence tests (five dogs) were also performed. Circulating antibodies to extractable nuclear antigens (ENA) were surveyed in 11 dogs by immunoblotting and ELISA. The predominant cells at the dermal-epidermal interface were identified as CD3(+) T lymphocytes expressing CD4 or CD8 and CD1(+) dendritic antigen presenting cells. In 7/12 dogs (58%), apoptosis of basal keratinocyte nuclei was present. Up-regulation of MHCII and ICAM-1 was observed on basal keratinocytes from the two dogs examined. Direct immunofluorescence revealed deposition of immunoglobulins bound to the cytoplasm of keratinocytes (6/14 dogs; 43%), to the dermal-epidermal junction (7/14 dogs; 50%), or to superficial dermal venules (13/14 dogs; 93%). Circulating IgG auto-antibodies targeting one or more ENA were detected in nine (82%) and eight (73%) of 11 dogs by immunoblotting and ELISA, respectively. These auto-antibodies recognized Ro/SSA and/or La/SSB in four (36%) and six (55%) of 11 dogs respectively by these two methods. Altogether, results of these studies provide evidence supporting the hypothesis that canine VCLE is an immunological homologue of subacute cutaneous lupus erythematosus in humans.

ICAM-1 upregulation in the spinal cords of PLSJL mice with experimental allergic encephalomyelitis is dependent upon TNF-α production triggered by the loss of blood–brain barrier integrity

Urate (UA) selectively scavenges peroxynitrite-dependent radicals and suppresses CNS inflammation through effects that are manifested at the blood–brain barrier (BBB). ICAM-1 upregulation in the spinal cord tissues of myelin basic protein (MBP) immunized mice is selectively inhibited by UA treatment. In contrast, the expression of ICAM-1 and other adhesion molecules by circulating cells is unchanged. Moreover, TNF-α expression in the CNS tissues of MBP-immunized mice is suppressed by UA treatment but TNF-α-induced ICAM-1 expression on neurovascular endothelial cells is not. Therefore the effect of UA on ICAM-1 upregulation in the CNS tissues is likely due to its known contribution to the maintenance of BBB integrity in MBP-immunized mice which in turn inhibits cell invasion into the CNS and prevents TNF-α production in CNS tissues.