Vascular endothelial cell expression of ICAM-1 and VCAM-1 at the onset of eliciting contact hypersensitivity in mice: evidence for a dominant role of TNF-alpha

We have studied vascular endothelial activation and increased expression of ICAM-1 and VCAM-1 at the onset of the elicitation phase of oxazolone contact hypersensitivity in mice. By measuring the local uptake of i.v. administered radiolabeled anti-ICAM-1 and anti-VCAM-1 mAb, we found that endothelial ICAM-1 and VCAM-1 was increased by 4 h after challenge, 2 h later than the first peak of ear swelling and 125I-labeled human serum albumen uptake. Increased expression of endothelial ICAM-1 and VCAM-1 was significantly greater in sensitized animals than in naive animals. Anti-TNF-alpha antiserum significantly inhibited both the increase in ear thickness (p < 0.01), and the up-regulation of ICAM-1 and VCAM-1 expression (p < 0.01 for both) at 4 h. In contrast, the combination of anti-IL-1alpha and IL-1beta had only a small inhibitory effect on ICAM-1 expression (p < 0.05) and no significant effect on increased ear thickness or on VCAM-1 expression. A mixture of anti-TNF-alpha, anti-IL-1alpha, and IL-1beta was no more inhibitory for endothelial ICAM-1 and VCAM-1 expression than anti-TNF-alpha alone. ICAM-1 and VCAM-1 expression at 4 h was unaffected by a combination of mAb against alpha4 and beta2 integrins, whereas expression at 24 h was significantly inhibited (p < 0.05), suggesting that the release of TNF-alpha and other cytokines involved in the initiation of the response may not require leukocyte traffic or other leukocyte functions involving these integrins. We conclude that the early up-regulation of endothelial ICAM-1 and VCAM-1 during the elicitation of contact hypersensitivity is primarily due to the immune-dependent local release of TNF-alpha.     

Scarring trachoma is associated with polymorphism in the tumor necrosis factor alpha (TNF-alpha) gene promoter and with elevated TNF-alpha levels in tear fluid

Tumor necrosis factor alpha (TNF-alpha) may play a central role in the disease pathogenesis which occurs as a consequence of chlamydial infection. To investigate the importance of TNF-alpha gene promoter polymorphisms and TNF-alpha levels in tear fluid in scarring trachoma, a large matched-pair case-control study was performed in The Gambia. The -308A allele was present in a higher proportion of patients (28.4%) than controls (18.4%), with an increasing association for homozygotes (chi2 for trend, P = 0.032; allele frequency, 0.163 in patients and 0.099 in controls; chi2, P = 0.025). For the -238A allele, the association was similar but not significant. The disease association was highly significant when the number of either -308A or -238A sites in an individual was considered (P = 0.003). TNF-alpha promoter alleles are tightly linked to some HLA class I and II alleles, but multivariate analysis confirmed that the disease associations were independent of HLA, although a class I allele, A*6802, is also associated with disease. TNF-alpha was more frequently detected in tear samples from patients (27.6%) than from controls (15.9%), increasingly so for higher levels of detectable TNF-alpha (P = 0.015). Among patients, detectable TNF-alpha in tears was highly associated with the presence of ocular chlamydial infection (P < 0.001). The results indicate that TNF-alpha plays a major role in the tissue damage and scarring which occurs as a consequence of Chlamydia trachomatis infection.     

Heme induces the expression of adhesion molecules ICAM-1, VCAM-1, and E selectin in vascular endothelial cells

Heme is an important immunostimulating agent and oxidative factor contributing to endothelial cell activation. To investigate the mechanism of heme-induced endothelial cell activation, we analyzed the effect of heme and the inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), on the expression of the heme-degrading stress protein, heme oxygenase (HO), and adhesion molecules in human umbilical vein endothelial cells (HUVEC). Indirect immunofluorescence double labeling studies demonstrated a simultaneous increase of ICAM-1 and HO-1 after exposure of cells to heme for 24 hr. Co-expression of HO-1 and ICAM-1 was also demonstrated in TNF-alpha-exposed cells. Dot blot immunoassay and quantitative analysis by ELISA demonstrated that heme treatment for 24 hr caused a 2-fold increase in ICAM-1 expression (P < 0.002) compared with quiescent cells, while in cells stimulated by TNF-alpha for 24 hr ICAM-1 gene expression increased by 5-fold. Moreover, heme exposure also resulted in a marked increase in VCAM-1 and E selectin expression (three and four times over control levels, respectively). On the other hand, TNF-alpha treatment showed similar expression levels for VCAM-1 and E selectin, compared with stimulation by heme (100 microM). The level of HO activity in endothelial cells exposed to heme or TNF-alpha was increased from 24.7 +/- 5.7 pmol bilirubin/mg protein/min in control to 70.0 +/- 9.5 and 36.7 +/- 3.1 pmol bilirubin/mg protein/min in heme- and TNF-alpha-stimulated cells, respectively. These results suggest that upregulation of ICAM-1, VCAM-1, and E selectin expression is associated with oxidative stress induced by hemoglobin/heme and that HO-1 may play a modulating role via its ability to degrade heme to a substance with antioxidant properties.     

Mast cells of psoriatic and atopic dermatitis skin are positive for TNF-alpha and their degranulation is associated with expression of ICAM-1 in the epidermis

The release of cytokines from cutaneous cells may be of major importance in the initiation and development of many inflammatory skin disorders. For example, tumor necrosis factor-alpha (TNF-alpha), which in healthy skin is found preformed only in mast cells, is able to induce the expression of several adhesion molecules including intercellular adhesion molecule-1 (ICAM-1). Increased expression of ICAM-1 occurs in keratinocytes in lesional skin of psoriasis and atopic dermatitis (AD) and it is considered to be an important initiator of leucocyte/keratinocyte interactions in skin inflammation. We counted the mast cells showing TNF-alpha immunoreactivity using a double-staining method in nonlesional and lesional skin sections from 12 patients with AD and 12 patients with psoriasis. The percentage of TNF-alpha+ mast cells in lesional and nonlesional AD skin was 36 +/- 22% and 21 +/- 15% (P < 0.018, paired t-test), respectively, and in psoriatic skin was 16 +/- 25% and 15 +/- 15%, respectively (P < 0.89, paired t-test). We also cultured whole skin biopsies taken from the healthy-looking skin of psoriatic and AD patients in the presence of mast cell degranulator compound 48/80, which resulted in focal expression of ICAM-1 in the epidermis. In cultured keratinocytes, both histamine and an extract of a human mast-cell line (HMC-1) induced ICAM-1 immunostaining only in occasional cells, but the combination of histamine and the HMC-1 extract resulted in intense ICAM-1 staining in numerous cells. This enhancement of ICAM-1 staining was abolished by preincubation of the HMC-1 extract with anti-TNF-alpha antibody. These results suggest that the degranulation of mast cells induces the expression of ICAM-1 in keratinocytes probably via TNF-alpha and histamine.     

VCAM-1 is internalized by a clathrin-related pathway in human endothelial cells but its alpha 4 beta 1 integrin counter-receptor remains associated with the plasma membrane in human T lymphocytes

Lymphocyte extravasation involves a step(s) of de-adhesion to allow trans- and subendothelial migration in response to inflammatory signals. We show here that ligated VCAM-1 was rapidly internalized (t1/2 14.5 min) in ECV 304 endothelial cells and in TNF-alpha-primed human umbilical vein-derived endothelial cells (t1/2 11.2 min). The process required energy (ATP), intracellular Ca2+, an intact cytoskeletal network and active protein kinases. The internalization of VCAM-1 involved a clathrin-dependent pathway based on the observations that 1) it was inhibited in cells treated with lysosomotropic agents or with a hypertonic concentration of sucrose, and 2) internalized VCAM-1 colocalized with clathrin. In contrast, the cross-linked alpha 4 beta 1 integrin counter-receptor of VCAM-1 remained associated with the plasma membrane of purified peripheral T and Jurkat cells. Our results suggest a model where VCAM-1 would initially participate in the retention of T cells to the endothelium by binding alpha 4 beta 1 integrin. Lymphocyte de-adhesion would be facilitated as a result of the internalization of VCAM-1. The persistent cell surface expression of alpha 4 beta 1 integrin would allow the migrating T cells to interact with and receive signal(s) from its fibronectin ligand of the extracellular matrix.     

Increased expression of intercellular adhesion molecule-1 (ICAM-1) in diabetic rat glomeruli: glomerular hyperfiltration is a potential mechanism of ICAM-1 upregulation

Mononuclear cells, including monocytes/macrophages and T-cells, are considered to be involved in the progression of diabetic nephropathy, although the mechanism of their recruitment into diabetic glomeruli is unclear. The intercellular adhesion molecule-1 (ICAM-1) promotes the infiltration of leukocytes into atherosclerotic lesions as well as inflammatory tissues. In the present study, we investigated the expression of ICAM-1 in the glomeruli of streptozotocin-induced diabetic rats. The expression of ICAM-1 was increased significantly during the early stage of diabetes. The number of mononuclear cells, primarily monocytes/macrophages and lymphocytes, was significantly increased in diabetic glomeruli. Mononuclear cell infiltration into diabetic glomeruli was prevented by anti-ICAM-1 monoclonal antibody. Insulin treatment decreased ICAM-1 expression and mononuclear cell infiltration. The ICAM-1 expression on cultured human umbilical vein endothelial cells was not induced under high glucose culture conditions. Glomerular hyperfiltration is a characteristic change in the early stage of diabetic nephropathy. Treatment with aldose reductase inhibitor, which prevented glomerular hyperfiltration without changes in blood glucose levels, decreased ICAM-1 expression and mononuclear cell infiltration. Moreover, we examined the ICAM-1 expression in the glomeruli of the 5/6 nephrectomized rat, which is a model for glomerular hyperfiltration without hyperglycemia. The ICAM-1 expression and infiltration of mononuclear cells was significantly increased in the glomeruli of 5/6 nephrectomized rats. We conclude that ICAM-1 is upregulated and promotes the recruitment of mononuclear cells in diabetic glomeruli. Moreover, glomerular hyperfiltration that occurs in the early stage of diabetic glomeruli may be one of the potential mechanisms of ICAM-1 upregulation in diabetic nephropathy.     

Neutrophil apoptosis is associated with a reduction in CD16 (Fc gamma RIII) expression

Resolution of inflammation involves removal of recruited neutrophils from inflamed sites via a noninflammatory mechanism, possibly involving neutrophil apoptosis and engulfment/phagocytosis by macrophages. In this study, we describe the reduction in surface expression (> 90%) of the neutrophil molecule Fc gamma RIII (CD16) during in vitro culture at 37 degrees C, which was found to be temporally associated with the appearance of neutrophils with apoptotic morphology during in vitro culture and inhibitable by granulocyte-macrophage colony-stimulating factor (GM-CSF), which postpones apoptosis in the neutrophil. By using dual fluorescence analysis, CD16 "low" expressing neutrophils showed reduced staining with the DNA-binding dye propidium iodide, suggesting that CD16 low expressing neutrophils were apoptotic. Separation of CD16 "high" and CD16 "low" expressing neutrophils by fluorescence-activated cell sorting revealed that morphologically apoptotic cells exhibited the CD16 low phenotype. We did not observe similar marked changes in expression of other neutrophil surface molecules (including other phosphatidylinositol (PI)-linked molecules), indicating that generalized loss of surface molecules does not occur during apoptosis. We believe this to be the first reported cell type-specific membrane alteration in a surface glycoprotein associated with apoptosis, suggesting that the program of cell death in the neutrophil, in addition to morphologic and nuclear changes, includes alterations in expression of surface receptors.     

Immunohistochemical localization of p21(WAF1/CIP1) in normal, hyperplastic, and neoplastic uterine tissues

Assuming that the chemical reactions used to synthesize a combinatorial library member are successful, then knowledge of the specific reaction sequence is equivalent to knowing the member's chemical identity. Because the determination of chemical identity is typically not automatable and requires a substantial amount of material, schemes that encode a member's reaction history onto the reaction platform are of value. The primary benefits of encoding are relational nomenclature (all methods) and automated handling (some methods). Encoding methods evaluated to date are spatial, graphical, chemical, spectrometric, electronic, and physical.     

Suppression of experimental autoimmune encephalomyelitis with a TNF binding protein (TNFbp) correlates with down-regulation of VCAM-1/VLA-4

The effect of a novel TNF binding protein (TNFbp), a polyethylene glycol-linked form of the type I soluble receptor of TNF, on the expression of adhesion molecules has been investigated with a passive transfer model of experimental autoimmune encephalomyelitis (EAE) in SJL/J mice. The expression of L-selectin, VLA-4 and LFA-1 on spleen cells of EAE animals treated with TNFbp or saline was examined by FACS analysis. The expression of VCAM-1 and ICAM-1 was investigated by immunochemistry in spinal cord tissue of SJL/J mice with EAE. In animals sensitized for EAE and treated with TNFbp, the expression of VCAM-1 in the central nervous system as well as VLA-4 on spleen cells was clearly diminished. Reduction in VCAM-1 staining and VLA-4 expression corresponded to inhibition of inflammation in the spinal cord and to prevention of clinical signs of EAE. The results have also shown that myelin basic protein responses as well as non-antigen-specific responses were not diminished in animals treated with TNFbp. The findings suggest that TNFbp might prevent EAE development by modulating the expression of VCAM-1 and VLA-4.     

MDR1 expression is associated with adverse survival in melanoma of the uveal tract

Metastatic uveal melanoma is profoundly chemoresistant and has a very poor outcome. We have previously shown that the MDR1 gene and its gene product P-glycoprotein (P-gp), which are known to cause drug resistance in cancer cells, are expressed in ocular melanoma. Overexpression of MDR1 has been associated with a poor survival in some tumor types treated by chemotherapy and in some untreated tumours. To assess whether MDR1 expression is of prognostic value in uveal melanoma, we evaluated the expression of MDR1 by immunohistochemistry in 108 cases. Three semiquantitative grades were used to evaluate positive staining. We detected MDR1 expression in 80% of cases; 28% showed grade I staining; 30%, grade II staining; and 22%, grade III staining. There was a statistically significant association (P=.004) between MDR1 expression by tumor cells and shorter survival times (n=96), which was most striking at grade III levels of expression. Multivariate analysis showed that MDR1 expression is an independent prognostic indicator of poor survival. We conclude that (1) MDR1 may be involved in chemoresistance and tumor propagation in primary uveal melanoma, and (2) increasing levels of expression are prognostically significant and may prove a useful marker of tumor invasiveness, independent of established prognostic factors.     

Apoptosis in rat prostatic adenocarcinoma is associated with rapid infiltration of cytotoxic T-cells and activated macrophages

The laser has played a valuable primary and adjunctive role in the management of nasal and sinus disorders. When using the laser there must be appropriate knowledge about safety, instrumentation, and types of pathologic conditions in which the laser is effective. The laser is effective for turbinate dysfunction of various causes. Its coagulating, cutting, and vaporization ability make it useful in managing intranasal vascular disorders such as hereditary hemorrhagic telangiectasia and hemangioma. There is some promise in using the laser for nasal polyposis with eosinophilia.     

Increased expression of the NME1 gene is associated with metastasis in epithelial ovarian cancer

The genetic events involved in the development of metastases of epithelial ovarian cancer are largely unknown. One gene postulated to play a role in tumour metastasis suppression is NME1 (nm23-H1), and an inverse relationship between NME1 expression and metastatic potential has been observed for some solid tumours. In this study we have investigated the levels of mRNA expression of the 2 isoforms of the NME gene, NME1 and NME2. A maximum of 45 tumours samples from 33 patients were available for Northern blot analysis. We observed variable levels expression of NME1 and NME2 mRNA. The average level of NME1, but not NME2, mRNA expression was statistically higher in metastatic biopsies when compared with primary tumour biopsies. To examine the possible tumour suppressor gene role of NME1 in ovarian tumours, 76 patients were investigated by Southern blot analysis to determine the rate of allelic deletion. Allele loss at 5 other chromosome 17 loci (D17S5, TP53, NF1, D17S74, D17S4) was also evaluated for many of these 76 patients. Allele loss was observed in 22/30 (73%) informative patients at the NME1 locus. We also observed high rates of allele loss at the other loci evaluated. No correlations with clinical stage, histological subtype or patient survival were observed in either mRNA or DNA analyses. We have established that tumour progression in ovarian cancer is accompanied by over-expression of the NME1 gene; however, despite high rates of allele loss at the NME1 locus, the concept that NME1 may be a candidate tumour suppressor gene in ovarian cancer cannot be confirmed by this study.     

VCAM-1 expression and leukocyte trafficking to the CNS occur early in infection with pathogenic isolates of SIV

This study reports on the endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) in the central nervous system (CNS) early after experimental infection of rhesus monkeys (Macaca mulatta) with pathogenic and nonpathogenic simian immunodeficiency virus (SIV). Diffuse endothelial expression of VCAM-1 was observed in the CNS in all animals receiving pathogenic SIV. These findings demonstrate the rapidity with which pathogenic SIV is able to enter the CNS and induce endothelial cell activation.