Chemokine Receptors in Human Endothelial Cells
FUNCTIONAL EXPRESSION OF CXCR4 AND ITS TRANSCRIPTIONAL REGULATION BY INFLAMMATORY CYTOKINES*
- From the Department of Cardiovascular Pharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406
Abstract
Chemokines play an important role in the regulation of endothelial cell (EC) function, including proliferation, migration and differentiation during angiogenesis, and re-endothelialization after injury. In this study, reverse transcriptase-polymerase chain reaction was used to reveal expression of various CXC and CC chemokine receptors in human umbilical vein EC. Northern analysis showed that CXCR4 was selectively expressed in vascular EC, but not in smooth muscle cells. Compared with other chemokines, stromal cell-derived factor-1α (SDF-1α), the known CXCR4 ligand, was an efficacious chemoattractant for EC, causing the migration of ∼40% input cells with an EC50 of 10–20 nm. Of the chemokines tested, only SDF-1α induced a rapid, though variable mobilization of intracellular Ca2+in EC. Experiments with actinomycin D demonstrated that CXCR4 transcripts were short-lived, indicating a rapid mRNA turnover. Interferon-γ (IFN-γ) caused a pronounced down-regulation of CXCR4 mRNA in a concentration- and time-dependent manner. In a striking functional correlation, IFN-γ treatment also attenuated the chemotactic response of EC to SDF-1α. IL-1β, tumor necrosis factor-α, and lipopolysaccharide produced a time course-dependent biphasic effect on CXCR4 transcription. Expression of CXCR4 in EC is significant, more so as it and several CC chemokine receptors have been shown to serve as fusion co-receptors along with CD4 during human immunodeficiency virus infection. Taken together, these findings provide evidence of chemokine receptor expression in EC and offer an explanation for the action of chemokines like SDF-1α on the vascular endothelium.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ To whom correspondence should be addressed: Dept. of Cardiovascular Pharmacology, Mail Code UW2511, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406. Tel.: 610-270-5578; Fax: 610-270-5080; E-mail: Shalley_K_Gupta{at}sbphrd.com.
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↵1 The abbreviations used are: EC, endothelial cell(s); CCR, CC chemokine receptor; CXCR, CXC chemokine receptor; FACS, fluorescence-activated cell sorter; FBHEC, fetal bovine heart endothelial cell(s); HUVEC, human umbilical vein endothelial cell(s); HCAEC, human coronary artery endothelial cell(s); HBMEC, human brain microvascular endothelial cell(s); IFN, interferon; LPS, lipopolysaccharide; TNF, tumor necrosis factor; PCR, polymerase chain reaction; RT-PCR, reverse transcription PCR; IL, interleukin; HIV, human immunodeficiency virus; PBS, phosphate-buffered saline; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; RANTES, regulated on activation normal T cell expressed and secreted.
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- Received August 5, 1997.
- Revision received December 7, 1997.
- The American Society for Biochemistry and Molecular Biology, Inc.
