Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial glycoprotein which mediates leukocyte-endothelial cell interactions. To study the pathogenetic significance of VAP-1 in inflammatory disorders, an in vivo immunodetection method was used to detect the regulation of luminally expressed VAP-1 in experimental skin and joint inflammation in the pig and dog. Moreover, VAP-1 was studied as a potential target to localize inflammation by radioimmunoscintigraphy. Up-regulation of VAP-1 in experimental dermatitis and arthritis could be visualized by specifically targeted immunoscintigraphy. Moreover, the translocation of VAP-1 to the functional position on the endothelial surface was only seen in inflamed tissues. These results suggest that VAP-1 is both an optimal candidate for anti-adhesive therapy and a potential target molecule for imaging inflammation. Leukocyte migration into tissues is vital for efficient defense against insulting pathogens and foreign antigens. Nevertheless, the same phenomenon is also crucial to inappropriate inflammation and tissue destruction in several types of acute and chronic inflammatory and autoimmune diseases such as rheumatoid arthritis, inflammatory bowel diseases, organ transplant rejection, and ischemia-reperfusion injury. Leukocytes enter from the blood circulation into the tissues by passing through the walls of blood vessels. An essential step in this process is binding of leukocytes to the innermost layer of the blood vessel wall, the endothelium, by adhesion molecules. Multiple adhesion molecules on the leukocytes interact concertedly with their counter-receptors on the endothelium during the adhesion and the subsequent transmigration process.1,2 A change in the functional expression of adhesion molecules on the endothelial surface is an early and specific indicator of inflammation. In fact, recent studies suggest that radioactively labeled monoclonal antibodies against specific endothelial adhesion molecules can be used in the diagnosis of inflammation by nuclear imaging methods. 3,4Human vascular adhesion protein-1 (VAP-1), originally defined by 1B2 monoclonal antibody, is a 170-kd endothelial sialoglycoprotein.5 VAP-1 is inflammation inducible and mediates the early phases of interaction between lymphocytes and endothelium. 6 The expression pattern of VAP-1 in normal and inflamed human tissues has been described 7,8 and the role of VAP-1 in human leukocyte adhesion has been shown in vitro. 5,9 However, practically nothing is known about the translocation of VAP-1 from the inside of the cells to the functional position on the cell surface as well as the significance of VAP-1 in leukocyteendothelium interactions in vivo.The anti-human-VAP-1 mAb 1B2 does not recognize VAP-1 of small laboratory animals such as mouse, rat, or rabbit. However, preliminary screening experiments revealed that 1B2 antibody does recognize porcine and canine blood vessels. That encouraged us to study whether the antigens recognized by 1B2 are the porcine and canine homologues o...

Human vascular adhesion protein-1 (VAP-1) is a dualfunction molecule with adhesive and enzymatic properties. In addition to synthesis in endothelial cells1 In endothelial cells, VAP-1 is localized both in conspicuous cytoplasmic granules and on the luminal surface. Under physiological conditions, the synthesis of VAP-1 is most prominent in high endothelial venules (HEVs) of peripheral lymph node-type lymphatic organs, but it is also inducible in vessels at other locations in the setting of inflammation.2 In endothelial cells VAP-1 is expressed as a homodimer of two 90-kd subunits. VAP-1 isolated from HEVs is an abundantly sialylated glycoprotein, and the sialic acid decorations are a prerequisite to the adhesive function of VAP-1.

The results suggest that the use of the levonorgestrel-releasing intrauterine system is not associated with an increased risk of breast cancer.

Human P-selectin, ICAM-1 and VAP-1 appear to be the most promising targets when antiadhesive interventions preventing leukocyte-mediated tissue destruction after myocardial ischemia are planned.

Background:Epothilones are a novel group of microtubule (mt) targeting cancer drugs that bind to the β-subunit of the αβ-tubulin dimer. Epothilones inhibit cell proliferation and induce cell death by interfering with the normal mt function. In this study, we examined the consequences of altered expression of human β-tubulin isotypes in terms of the epothilone drug response in human lung and breast cancer cell lines.Methods:The β-tubulin isotypes TUBB2A–C, TUBB3 and TUBB were silenced or overexpressed in A549, A549EpoB40 and MCF7 cell lines in the presence or absence of epothilones. The drug effects on cell proliferation, mitosis and mt dynamics were determined using live cell microscopy and immunofluorescence assays.Results:Loss of TUBB3 enhanced the action of epothilones. TUBB3 knockdown increased the severity of drug-induced mitotic defects and resulted in stabilisation of the mt dynamics in cells. Moreover, exogenous expression of TUBB3 in the epothilone resistant cell line conferred the response to drug treatments. In contrast, reduced levels of TUBB2A–C or TUBB had not apparent effect on the cells' response to epothilones.Conclusion:Our results show that the expression of TUBB3 contributes to the cellular response to epothilones, putatively by having an impact on the mt dynamics.

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IntroductionVascular adhesion protein-1 (VAP-1) is an adhesion molecule, which upon inflammation is rapidly translocated from intracellular sources to the endothelial cell surface. We have recently discovered that sialic acid- binding immunoglobulin-like lectin 9 (Siglec-9) is a leukocyte ligand of VAP-1 and that 68Ga-labeled Siglec-9 motif peptide facilitates in vivo imaging of inflammation. This study evaluated the feasibility of 68Ga-DOTA-Siglec-9 positron emission tomography (PET) for the assessment of synovitis.MethodsRabbits with synovial inflammation were injected with 18F-FDG or 68Ga-DOTA-Siglec-9 and studied by gamma counting and autoradiography. Certain rabbits were also examined with magnetic resonance imaging (MRI). After PET imaging, rabbits were intravenously administered with anti-VAP-1 antibody to evaluate luminal expression of VAP-1 by immunohistochemistry. Finally, binding of Siglec-9 peptide and VAP-1 positive vessels were evaluated by double staining of rheumatoid arthritis synovium.ResultsIntra-articular injection of hemagglutinin induced mild synovial inflammation in rabbit knee with luminal expression of VAP-1. Synovitis was clearly visualized by 68Ga-DOTA-Siglec-9 PET in addition to 18F-FDG-PET and MRI. Compared with the 18F-FDG, the ex vivo inflamed-to-control synovium ratio of 68Ga-DOTA-Siglec-9 was similar (1.7 ± 0.4 vs. 1.5 ± 0.2, P = 0.32). Double staining revealed that Siglec-9 peptide binds to VAP-1 positive vessels in human rheumatoid synovium.ConclusionGa-DOTA-Siglec-9 PET tracer detected VAP-1 positive vasculature in the mild synovitis of rabbits comparable with 18F-FDG, suggesting its potential for in vivo imaging of synovial inflammation in patients with rheumatic diseases.

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