Cariporide inhibits high glucose-mediated adhesion of monocyte-endothelial cell and expression of intercellular adhesion molecule-1

The aim of this study was to examine whether cariporide, a new inhibitor of Na(+)/H(+) exchanger 1 (NHE-1), may inhibit high glucose-induced monocyte-endothelial cell adhesion and the expression of intercellular adhesion molecule-1 (ICAM-1). Cultured endothelial cells were incubated with normal glucose control (5.5 mM), cariporide control (5.5 mM glucose plus 10 microM cariporide), hyperosmolarity (5.5 mM glucose plus 16.5 mM mannitol), high glucose (HG, 22 mM), low-concentration cariporide (22 mM glucose plus 0.1 microM cariporide), medium-concentration cariporide (22 mM glucose plus 1 muM cariporide), and high-concentration cariporide (22 mM glucose plus 10 microM cariporide) for 24 h. Monocytes were isolated from peripheral human blood. Adhered monocytes were quantified by measuring their protein content. ICAM-1 expression and NHE-1 activity was determined with enzyme-linked immunosorbent assay (ELISA) and pH-sensitive fluorescent spectrophotometry. Exposure of endothelial cells to HG for 24 h caused an increase of adhesion of monocytes to endothelial cells and an increased expression of ICAM-1. However, these effects were reversed by treatment with cariporide (0.1, 1, 10 microM) in a concentration-dependent manner. Furthermore, cariporide (1 microM) was able to inhibit the activation of NHE-1 induced by HG in endothelial cells. These findings suggest that cariporide might inhibit HG-mediated monocyte-endothelial cell adhesion and expression of ICAM-1 by inhibiting the activation of NHE-1.     

Endothelial intercellular cell adhesion molecule 1 contributes to cell aggregate formation in CHO cells cultured in serum-free media

Chinese hamster ovary (CHO) cells have been adapted to grow in serum-free media and in suspension culture to facilitate manufacturing needs. Some CHO cell lines, however, tend to form cell aggregates while being cultured in suspension. This can result in reduced viability and capacity for single cell cloning (SCC) via limiting dilution, and process steps to mitigate cell aggregate formation, for example, addition of anti-cell-aggregation agents. In this study, we have identified endothelial intercellular cell adhesion molecule 1 (ICAM-1) as a key protein promoting cell aggregate formation in a production competent CHO cell line, which is prone to cell aggregate formation. Knocking out (KO) the ICAM-1 gene significantly decreased cell aggregate formation in the culture media without anti-cell-aggregation reagent. This trait can simplify the process of transfection, selection, automated clone isolation, and so on. Evaluation in standard cell line development of ICAM-1 KO and wild-type CHO hosts did not reveal any noticeable impacts on titer or product quality. Furthermore, analysis of a derived nonaggregating cell line showed significant reductions in expression of cell adhesion proteins. Overall, our data suggest that deletion of ICAM-1 and perhaps other cell adhesion proteins can reduce cell aggregate formation and improve clonality assurance during SCC.     

Immunoenzymometric analysis for expression and shedding of intercellular adhesion molecule-1 on human endothelial cells stimulated with cytokines or lipopolysaccharide

Unstimulated endothelial cell (EC)cultures express low levels of intercellular adhesion molecule-1 (ICAM-1) and their expression can be enhanced by inflammatory cytokines such as tumor necrosis factor (TNF). Three monoclonal antibodies (MoAbs) highly reactive with TNF-stimulated human ECs were established and defined to recognize a 95 kDa cell surface protein specifically expressed on cytokine-activated ECs, which was immunochemically identified as ICAM-1. The quantitative immunoassay of soluble and insoluble ICAM-1 could be performed with two different MoAbs. Secretion of fibronectin or the von Willebrand factor, was not significantly enhanced with TNF stimulation. Cellular expression of ICAM-1 was drastically induced by TNF or interleukin-1 stimulation, and the moderate expression with delayed-action was observed only by lipopolysaccharide stimulation. A maximal amount of soluble ICAM-1 was released from ECs stimulated only by TNF, apparently in a dose dependent manner, but no significant release of ICAM-1 was induced by thrombin interleukin-2, or lipopolysacchardes. Released levels of soluble ICAM-1 from interleukin-1-stimulated ECs were apparently diminished as compared with those from TNF-stimulated cells. These results suggest that release of soluble ICAM-1 from EC surfaces can be most significantly enhanced by TNF-specific signaling, and prospectively, should be a sensitive indicator of intravascular inflammation in acute endothelium injury.     

Hyperglycemia increases the levels of vascular cellular adhesion molecule-1 and monocyte-chemoattractant-protein-1 in the diabetic endothelial cell

Hyperglycemia is the major cause of diabetic angiopathy. Aim of our study was to evaluate the impact of high glucose on cell growth and function of human "diabetic" endothelial cells (EC). Incubation of non-diabetic EC with glucose moderately inhibited cell growth and increased the expression of ICAM-1 and E-selectin. In the disease-specific EC, glucose treatment resulted also in moderately inhibited cell growth by 5-10%, increased basal expression of VCAM-1 by 10-20%, and an enhanced release of monocyte-chemoattractant-protein-1 (MCP-1) by 40-70%. The expression of ICAM-1 and E-selectin and the release of IL-6 and IL-8 was not affected. The usage of our disease-specific EC model might evaluate the impact of systemic factors of diabetic patients in the progression of endothelial dysfunction, and may be suitable to develop relevant therapeutic regimens.     

A multiparameter screening assay to assess the cytokine-induced expression of endothelial cell adhesion molecules

Compounds which inhibit endothelial cell inflammatory responses are believed to be of therapeutic value. The cell adhesion molecules E-selectin, ICAM-1, and VCAM-1 play important roles in inflammatory reactions by mediating leukocyte-endothelial interactions. To identify compounds which inhibit the expression of these adhesion molecules following cytokine stimulation we developed an assay which measures E-selectin, ICAM-1, and VCAM-1 in the same experiment. For this, we have taken advantage of the technology of time-resolved fluorimetry, which allows detection of several parameters in parallel, employing anti-E-selectin antibody labeled with europium, and anti-ICAM-1 and anti-VCAM-1 labeled with samarium and terbium, respectively. These antibodies were used to detect the respective antigens in human endothelial cells stimulated with TNFalpha or IL-1beta. In cross-competition assays these antibodies were found to bind specifically to TNF- or IL-1-stimulated cells. This assay, in which three parameters are measured in the same experiment, proved to be robust with signal to noise ratios of 25-35 for E-Selectin, 4-8 for ICAM-1, and 3-9 for VCAM-1. The assay proved to be reproducible in high-throughput screening. The experience with this assay demonstrates that multiple parameters can be measured in an enzyme-linked immunosorbent assay-type assay on cells by using time-resolved fluorimetry. The possibility of obtaining several parameters from one experiment is feasible under high-throughput screening conditions and is of interest for other experimental setups in which the simultaneous measurement of several parameters is desired.     

Testosterone inhibits tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression in human aortic endothelial cells

It was shown that an increase in the bacteriochlorophyll (BChl) c antenna size observed upon lowering growth light intensities led to enhancement of the hyperchromism of the BChl c Q(y) absorption band of the green photosynthetic bacterium Chloroflexus aurantiacus. With femtosecond difference absorption spectroscopy, it was shown that the amplitude of bleaching of the oligomeric BChl c Q(y) band (as compared to that for monomeric BChl a) increased with increasing BChl c content in chlorosomes. This BChl c bleaching amplitude was about doubled as the chlorosomal antenna size was about trebled. Both sets of findings clearly show that a unit BChl c aggregate in the chlorosomal antenna is variable in size and governed by the grow light intensity, thus ensuring the high efficiency of energy transfer within the BChl c antenna regardless of its size.     

Angiotensin II stimulates intercellular adhesion molecule-1 via an AT1 receptor/nuclear factor-kappaB pathway in brain microvascular endothelial cells

Microvascular changes in the brain are significant causes of cerebral edema and ischemia injury. A number of studies suggest that angiotensin (Ang) II may be involved in the initiation and regulation of processes occurring in brain ischemia. We recently reported that Ang II injures brain microvascular endothelial cells (BMEC) partially via stimulating intercellular adhesion molecule-1 (ICAM-1) expression. However, the signaling cascade leading to Ang II-induced ICAM-1 expression in BMEC was unclear. The present study tested the hypothesis that Ang II induces ICAM-1 expression via an AT1 receptor/nuclear factor-kappaB (NF-kappaB) pathway in BMEC. Ang II directly stimulated the expression of ICAM-1 mRNA and protein in primary cultured BMEC. Ang II treatment also resulted in the degradation of IkappaBalpha and increase of NF-kappaB p65 subunit in the nucleus as well as the DNA binding activity of nuclear NF-kappaB. These effects were abolished by pretreatment with the selective AT1 receptor antagonists, losartan and compound EXP-2528, or losartan plus the AT2 receptor antagonist PD123319, but not by PD123319 alone. Moreover, there were no significant differences between the losartan and losartan plus PD123319 groups. These findings indicate that Ang II-induced ICAM-1 upregulation in brain microvascular endothelial cells may be mediated via an AT1 receptor/NF-kappaB pathway.     

Competition between intercellular adhesion molecule-1 and a small-molecule antagonist for a common binding site on the alphal subunit of lymphocyte function-associated antigen-1

The lymphocyte function-associated antigen-1 (LFA-1) binding of a unique class of small-molecule antagonists as represented by compound 3 was analyzed in comparison to that of soluble intercellular adhesion molecule-1 (sICAM-1) and A-286982, which respectively define direct and allosteric competitive binding sites within LFA-1's inserted (I) domain. All three molecules antagonized LFA-1 binding to ICAM-1-Immunoglobulin G fusion (ICAM-1-Ig) in a competition ELISA, but only compound 3 and sICAM-1 inhibited the binding of a fluorescein-labeled analog of compound 3 to LFA-1. Compound 3 and sICAM-1 displayed classical direct competitive binding behavior with ICAM-1. Their antagonism of LFA-1 was surmountable by both ICAM-1-Ig and a fluorescein-labeled compound 3 analog. The competition of both sICAM-1 and compound 3 with ICAM-1-Ig for LFA-1 resulted in equivalent and linear Schild plots with slopes of 1.24 and 1.26, respectively. Cross-linking studies with a photoactivated analog of compound 3 localized the high-affinity small-molecule binding site to the N-terminal 507 amino acid segment of the alpha chain of LFA-1, a region that includes the I domain. In addition, cells transfected with a variant of LFA-1 lacking this I domain showed no significant binding of a fluorescein-labeled analog of compound 3 or ICAM-1-Ig. These results demonstrate that compound 3 inhibits the LFA-1/ICAM-1 binding interaction in a directly competitive manner by binding to a high-affinity site on LFA-1. This binding site overlaps with the ICAM-1 binding site on the alpha subunit of LFA-1, which has previously been localized to the I domain.     

Human soluble E-selectin immunoadhesin inhibits leukemic monocyte adhesion to endothelial cells

Immunoadhesins are immunoglobulin (Ig)-like chimeric proteins comprised of target-binding regions fused to the Fc-hinge region of Ig, and are designed to have a long half-life and antibody-like properties. In an effort to find a good candidate for therapeutic use for inflammatory responses, we constructed a soluble human E-selectin immunoadhesin containing the extracellular region of human E-selectin fused to the Fc-hinge region of human IgG, and determined its effects on leukocyte adhesion and rolling in vitro. Our results revealed that the adhesion of leukocytes to endothelial cells was efficiently inhibited in the presence of 50 nM E-selectin immunoadhesin. In addition, the E-selectin immunoadhesin significantly inhibited leukocyte rolling on endothelial cells in perfusion experiments performed at 1.0 dyne/cm(2) wall shear stress. These findings indicate that our E-selectin immunoadhesin decreases leukocyte attachment and rolling in vitro, suggesting that this immunoadhesin may be a promising candidate for therapeutic anti-inflammatory use.     

CXC chemokine ligand 12/Stromal cell-derived factor-1 regulates cell adhesion in human colon cancer cells by induction of intercellular adhesion molecule-1

Background

Gene therapy and viral therapy are used for cancer therapy for many years, but the results are less than satisfactory. Our aim was to construct a new recombinant adenovirus which is more efficient to kill hepatocarcinoma cells but more safe to normal cells.

Methods

By using the Cancer Targeting Gene-Viro-Therapy strategy, Apoptin, a promising cancer therapeutic gene was inserted into the double-regulated oncolytic adenovirus AD55 in which E1A gene was driven by alpha fetoprotein promoter along with a 55 kDa deletion in E1B gene to form AD55-Apoptin. The anti-tumor effects and safety were examined by western blotting, virus yield assay, real time polymerase chain reaction, 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, Hoechst33342 staining, Fluorescence-activated cell sorting, xenograft tumor model, Immunohistochemical assay, liver function analysis and Terminal deoxynucleotidyl transferase mediated dUTP Nick End Labeling assay.

Results

The recombinant virus AD55-Apoptin has more significant antitumor effect for hepatocelluar carcinoma cell lines (in vitro) than that of AD55 and even ONYX-015 but no or little impair on normal cell lines. Furthermore, it also shows an obvious in vivo antitumor effect on the Huh-7 liver carcinoma xenograft in nude mice with bigger beginning tumor volume till about 425 mm3 but has no any damage on the function of liver. The induction of apoptosis is involved in AD55-Apoptin induced antitumor effects.

Conclusion

The AD55-Apoptin can be a potential anti-hepatoma agent with remarkable antitumor efficacy as well as higher safety in cancer targeting gene-viro-therapy system.     

In vitro analysis of the melanoma/endothelium interaction increasing the release of soluble intercellular adhesion molecule 1 by endothelial cells

Melanoma cells constitutively release intercellular adhesion molecule 1 (ICAM-1) as soluble ICAM-1 (sICAM-1), and its levels are elevated in melanoma patients and correlate with disease progression. However, this correlation is not absolute, suggesting that specific characteristics of neoplastic cells and/or ICAM-1-positive non-neoplastic cells may influence the amounts of circulating sICAM-1. In this study, we found a weak correlation (r = 0.55; r ² = 0.3) between sICAM-1 release by 40 metastatic melanomas (36 primary cultures and 4 cell lines), and ICAM-1 expression on neoplastic cells. In addition, melanoma-secreted interleukin-1α (IL-1α) (1/40) but not vascular endothelial growth factor (VEGF) (29/40), significantly (P < 0.05) up-regulated the shedding of sICAM-1 by human umbilical vein endothelial cells (HUVEC). This was completely abolished by IL-1α/β neutralizing antibodies both at the protein and mRNA level. Altogether, our results suggest that (i) the extent of sICAM-1 release is distinctive for individual melanomas and can be independent of ICAM-1 expression; (ii) tumor endothelia may sustain levels of sICAM-1 in selected melanomas; (iii) melanoma-released VEGF does not affect ICAM-1 expression and sICAM-1 release by HUVEC. Melanoma-derived sICAM-1 inhibits cell-mediated cytotoxicity of melanoma cells; therefore, constitutive levels of sICAM-1 release and IL-1α secretion by individual melanomas can differentially influence tumor progression and the clinical effectiveness of cytotoxic-cell-based vaccines. Received: 15 October 1998 / Accepted: 17 February 1999     

Porphyromonas gingivalis fimbriae induce adhesion of monocytic cell line U937 to endothelial cells

This study used the human monocytic cell line U937 to examine whether or not Porphyromonas gingivalis fimbriae could induce the adhesion of monocytes to endothelial cells. An in vitro adhesion assay was used to investigate the effects of the fimbriae on U937 cell adhesion to human umbilical vein endothelial cells (HUVEC). The fimbriae enhanced U937 cell adhesion to HUVEC in a dose-dependent manner. U937 cells adhered better to HUVEC pretreated with the fimbriae for a minimum of 2 hr than to untreated HUVEC. The enhanced adhesion was inhibited by a monoclonal antibody against P. gingivalis 381 fimbriae. Pretreatment of U937 cells with the fimbriae for 24 hr enhanced U937 cell adhesion to HUVEC approximately 4-fold. This phenomenon was inhibited by an anti-CD11b antibody, suggesting the involvement of CD11b. These results indicate that P. gingivalis fimbriae can induce monocyte adhesion to the endothelial cell surface. They also suggest that the fimbriae may be involved in the initial event for infiltration of monocytes into the periodontal tissues of individuals with adult periodontitis.     

Contribution of intercellular adhesion molecule 1 (ICAM-1) to control Mycobacterium avium infection

Mycobacterium avium is a facultative intracellular opportunistic pathogen especially relevant in cases of people living with AIDS. The aim of this study was to evaluate the role of intercellular adhesion molecule 1 (ICAM-1) in the inflammatory response against M. avium infection. Mice deficient for ICAM-1 (ICAM KO) and infected with M. avium presented increased bacterial load in the spleen, liver and lungs compared to C57BL/6. Moreover, ICAM deficient mice presented reduced granuloma area in liver at 30 days post-infection with reduced numbers of lymphocytes and granulocytes. The assessment of in vitro cytokine production by ICAM KO spleen cells showed lower levels of IFN-γ compared to C57BL/6, whereas TNF-α remained unaltered. Additionally, the production of IFN-γ in liver and spleen tissues was also diminished in ICAM-1 KO mice. Interestingly, a persistent reduction in IFN-γ production was observed in CD3⁺NK1.1⁺ cells of ICAM-1 deficient mice compared to wild-type animals. Together, these results demonstrate the importance of ICAM-1 in the efficient control of M. avium infection and granuloma formation and highlights its role on CD3⁺NK1.1⁺ cell population as important for IFN-γ production during infection.     

Tat-APE1/ref-1 protein inhibits TNF-alpha-induced endothelial cell activation

Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/ref-1) is a multifunctional protein involved both in DNA base excision repair and redox regulation. In this study we evaluated the protective role of Tat-mediated APE1/ref-1 transduction on the tumor necrosis factor (TNF)-α-activated endothelial activation in cultured human umbilical vein endothelial cells. To construct Tat-APE1/ref-1 fusion protein, human full length of APE1/ref-1 was fused with Tat-protein transduction domain. Purified Tat-APE1/ref-1 fusion protein efficiently transduced cultured endothelial cells in a dose-dependent manner and reached maximum expression at 1 h after incubation. Transduced Tat-APE1/ref-1 showed inhibitory activity on the TNF-α-induced monocyte adhesion and vascular cell adhesion molecule-1 expression in cultured endothelial cells. These results suggest Tat-APE1/ref-1 might be useful to reduce vascular endothelial activation or vascular inflammatory disorders.     

细胞间粘附分子-1在血管内皮细胞冻融损伤中的作用

目的:探讨血管内皮细胞(VEC)表面细胞间粘附分子-1(ICAM-1)在VEC冻融损伤中的作用,以阐明冻融损伤的发病机制。方法:以大鼠主动脉VEC和大鼠外周血嗜中性粒细胞(PMN)为材料,使用WKL-Ⅴ型速率冷冻仪冷冻VEC然后在水浴中复温,制备VEC冻融模型。采用免疫组化法测定VEC冻融后4、12和24 h其表面ICAM-1的表达;将冻融VEC与正常PMN共同孵育后,以rose bengal染色法测定冻融VEC与PMN粘附,测定培养液中LDL活性确定VEC损伤程度。结果:冻融后4 h,VEC表面ICAM-1表达阳性率由冻融前的13.2%±3.6%增加至22.3%±4.4%,冻后12h达高峰(37.9%±2.5%)。冻融VEC与PMN共同孵育后,VEC-PMN粘附由对照组的0.204±0.025增加至0.363±0.022(P<0.01),培养液中LDH活性由对照组的104.64±20.14U/L增加至162.33±27.88U/L(P<0.01);ICAM-1Mab可部分阻断冻融VEC-PMN粘附(0.270±0.021,P<0.01),且使培养液中LDH活性降低至125.39±22.26U/L(P<0.05)。结论:冻融可诱发VEC表面ICAM-1的表达,进而增强VEC-PMN粘附而导致VEC损伤。     

The integrin alpha9beta1 mediates adhesion to activated endothelial cells and transendothelial neutrophil migration through interaction with vascular cell adhesion molecule-1

The integrin alpha9beta1 has been shown to be widely expressed on smooth muscle and epithelial cells, and to mediate adhesion to the extracellular matrix proteins osteopontin and tenascin-C. We have found that the peptide sequence this integrin recognizes in tenascin-C is highly homologous to the sequence recognized by the closely related integrin alpha4beta1, in the inducible endothelial ligand, vascular cell adhesion mole-cule-1 (VCAM-1). We therefore sought to determine whether alpha9beta1 also recognizes VCAM-1, and whether any such interaction would be biologically significant. In this report, we demonstrate that alpha9beta1 mediates stable cell adhesion to recombinant VCAM-1 and to VCAM-1 induced on human umbilical vein endothelial cells by tumor necrosis factor-alpha. Furthermore, we show that alpha9beta1 is highly and selectively expressed on neutrophils and is critical for neutrophil migration on VCAM-1 and tenascin-C. Finally, alpha9beta1 and alpha4 integrins contribute to neutrophil chemotaxis across activated endothelial monolayers. These observations suggest a possible role for alpha9beta1/VCAM-1 interactions in extravasation of neutrophils at sites of acute inflammation.     

Doxazosin inhibits human vascular endothelial cell adhesion, migration, and invasion

The quinazoline-derived alpha1-adrenoceptor antagonists, doxazosin and terazosin have been recently shown to induce an anoikis effect in human prostate cancer cells and to suppress prostate tumor vascularity in clinical specimens [Keledjian and Kyprianou, 2003]. This study sought to examine the ability of doxazosin to affect the growth of human vascular endothelial cells and to modulate vascular endothelial growth factor (VEGF)-mediated angiogenesis. Human umbilical vein endothelial cells (HUVECs) were used as an in vitro model to determine the effect of doxazosin on cell growth, apoptosis, adhesion, migration, and angiogenic response of endothelial cells. The effect of doxazosin on cell viability and apoptosis induction of human endothelial cells, was evaluated on the basis of trypan blue and Hoechst 33342 staining, respectively. Doxazosin antagonized the VEGF-mediated angiogenic response of HUVEC cells, by abrogating cell adhesion to fibronectin and collagen-coated surfaces and inhibiting cell migration, via a potential downregulation of VEGF expression. Furthermore there was a significant suppression of in vitro angiogenesis by doxazosin on the basis of VEGF-mediated endothelial tube formation (P < 0.01). Fibroblast growth factor-2 (FGF-2) significantly enhanced HUVEC cell tube formation (P < 0.01) and this effect was suppressed by doxazosin. These findings provide new insight into the ability of doxazosin to suppress the growth and angiogenic response of human endothelial cells by interfering with VEGF and FGF-2 action. This evidence may have potential therapeutic significance in using this quinazoline-based compound as an antiangiogenic agent for the treatment of advanced prostate cancer.     

Effect of irradiation-induced intercellular adhesion molecule-1 expression on natural killer cell-mediated cytotoxicity toward human cancer cells

Background aims

Irradiation enhances the adhesion between natural killer (NK) cells and target cells by up-regulating intercellular adhesion molecule-1 (ICAM-1) on target cells. Therefore, we investigated the effect of irradiation-induced ICAM-1 expression on human cancer cells on NK cell–mediated cytotoxicity.