Oncostatin M (OSM) is a member of the interleukin (IL)-6 cytokine family and modulates inflammatory responses. Here we investigated the role of OSM as an immunoregulatory factor for human cerebral endothelial cells (HCEC). Using RT-PCR we detected transcripts of the receptor components involved in OSM signaling, gp130, OSM receptor (OSMR)-beta, and leukemia inhibitory factor receptor (LIFR), in HCEC. A parallel FACS analysis revealed surface expression of gp130 and OSMR-beta, but not of LIFR on these cells. Functionally, OSM upregulated intercellular adhesion molecule-1, but did not induce vascular cell adhesion molecule-1 in HCEC. Further, OSM upregulated IL-6 and monocyte chemoattractant protein (MCP)-1, whereas IL-8 was unaffected. Combined application of tumor necrosis factor (TNF)-alpha and OSM synergistically enhanced IL-6 and MCP-1 production, but downregulated TNF-alpha-induced IL-8. As OSM regulated molecules relevant in inflammatory brain diseases, we investigated its expression in normal and pathological human brains. OSM was detected by immunohistochemistry in brains from multiple sclerosis patients in microglia, reactive astrocytes, and infiltrating leukocytes, whereas in normal brains and noninflammatory neurological diseases. immunoreactivity was absent from the parenchyma. These data suggest that immunoregulatory functions in human cerebral endothelial cells may be a mechanism by which OSM participates in the pathophysiology of inflammatory brain disease.
Endothelial cells of blood vessels forming the interphase between systemic circulation and tissues are crucial for maintenance of homeostasis and organ-related functions. Recent experiments support organ-specific endothelial differentiation and suggest differential gene expression patterns in endothelial cells. Here, we compared gene expression in primary human cerebral endothelial cells (HCEC), which are major constituents of the blood brain barrier (BBB), with human umbilical vein endothelial cells (HUVEC) by using cDNA array analysis of 375 genes. Under basal culture conditions, 35 genes were expressed only in HCEC, whereas 20 gene transcripts were detected only in HUVEC. A total of 78 genes were expressed in both endothelial cell types partly with distinct expression levels. Genes expressed by cerebral endothelial cells are important in vasculo- and angiogenesis (VEGF, erbB1) and immunoregulation (OSM-Rbeta, decorin, IL-6) or have growth-supporting properties (brain-derived neurotrophic factor, stem cell factor, transforming growth factor-beta). The differential gene expression profiles were confirmed at the protein level of cell cultures (ELISA, immunoblotting) and human tissues (immunohistochemistry). Identification and further functional characterization of genes specifically expressed by cerebral endothelial cells will have important impact on our understanding of endothelial function at the BBB.
Tumour necrosis factor-alpha ( TNF-alpha) has been proposed as one of the key mediators of inflammatory diseases of the CNS such as multiple sclerosis. It has been shown to induce the expression of adhesion molecules which is a prerequisite for the transmigration of immune cells through the blood-brain barrier. We therefore investigated the role of TNF-alpha in the expression and release of vascular cell adhesion molecule-1 (VCAM-1) in cultures of human cerebral endothelial cells (HCEC) in comparison with peripheral blood mononuclear cells (PBMC). A time- and dose-dependent expression of VCAM-1 and release of soluble VCAM-1 was detected in HCEC but not PBMC. TNF-alpha-induced release of soluble VCAM-1 was further increased by cotreatment with interferon-beta (IFN-beta), while IFN-beta alone did not affect VCAM-1 expression or the release of soluble VCAM-1. In addition, we observed that preincubation of PBMC with soluble VCAM-1 completely blocked their adhesion to HCEC. In conclusion, the proinflammatory effect of TNF-alpha on HCEC, which involves the induction of VCAM-1 expression and cellular adhesion, is followed by the consecutive effects of soluble VCAM-1 release in blocking adhesion and downregulating further cellular infiltration. Increasing soluble VCAM-1 release during active inflammation could be another mechanism by which IFN-beta treatment exerts protective effects in multiple sclerosis patients.
Gliomas are the most common intrinsic brain tumors. The degree of vascularization corresponds to malignancy and is related to prognosis. In order to retrieve information about tumor behavior in situ, the use of primary tissue material for experiments is advantageous. With increasing evidence for the importance of microenvironment and vascularization in tumor biology, we concentrated on the isolation of endothelial cells (EC) from primary tumor material to investigate the role of endothelium within tumor tissue. We developed a method for isolation and purification of tumor-derived endothelial cells. EC were isolated and cultivated from normal brain using tissue digestion and Percoll density gradient centrifugation resulting in a <95% of EC culture. For isolation of EC from gliomas of different malignancy grades a combination of tissue digestion, Percoll gradient centrifugation and magnetic bead sorting by anti-CD31, -VE-Cadherin and -CD 105 was employed. This approach provided a purity of <98%. Cells were classified and characterized by testing expression of CD105, CD31, VE-Cadherin, vWF, UEA-1 and measuring DiI-Ac-LDL-uptake. To exclude contamination, staining and negative selection with anti-SMA, -GFAP, and -CD68 was performed. Tumors were histopathologically diagnosed according to WHO classification. We isolated EC from normal brain (NBEC, n = 11), low-grade gliomas WHO II (LGEC, n = 22), and high-grade gliomas WHO III & IV (HGEC, n = 11). There were no clear differences in EC morphology between the different tumor grades. However, a significantly higher proliferation rate of HGEC compared to LGEC was observed as well as distinctive antigen expression. Already in early passages isolated EC showed a rapid change in antigen expression indicating a phenotypic shift under culture conditions. We could establish a protocol for reliable and reproducible isolation and culture of EC from gliomas with different WHO grading. In first phenotypical and functional analyses, NBEC, LGEC and HGEC show remarkable differences. EC from all tumors could be grown in culture. However, passage related changes of EC phenotype demand very early passages to work with.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.