Regulation of Expression of the Human Monocyte Chemotactic Protein-1 Receptor (hCCR2) by Cytokines

Tangirala, Rajendra K.; Murao, Koji; Quehenberger, Oswald

doi:10.1074/jbc.272.12.8050

Cited by 106 publications

(85 citation statements)

References 47 publications

(39 reference statements)

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“…Our results in CD14 ϩ CD16 ϩ cells were paralleled by findings in human blood monocytes that LPS or the proinflammatory cytokines TNF-␣, IL-1, or IFN-␥ but not growth factors, such as M-CSF, down-regulate mRNA and protein expression of CCR2 by decreasing mRNA stability, and subsequently impaired functional responses to MCP-1 [23,24,38,39]. Similarly, the lower CCR2 expression in CD14 ϩ CD16 ϩ cells may be due to reduced mRNA stability.…”

Section: Discussionsupporting

confidence: 67%

“…Similarly, the lower CCR2 expression in CD14 ϩ CD16 ϩ cells may be due to reduced mRNA stability. In contrast, CCR5 was less affected by cytokines [23,38,39]; however, it was up-regulated during maturation of monocytes in adherent culture [26]. The CD14 ϩ CD16 ϩ monocyte subset is expanded in sepsis, where this is preceded by peaks in the production of the monocyte-activating factors TNF-␣, IL-6, and M-CSF [6][7][8].…”

Section: Discussionmentioning

confidence: 99%

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Differential chemokine receptor expression and function in human monocyte subpopulations

Weber

Belge

Hundelshausen

et al. 2000

Journal of Leukocyte Biology

339

250

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The subset of human blood monocytes expressing low levels of CD14 and high levels of CD16 (CD14 ؉ CD16 ؉ ) exhibits features resembling mature tissue macrophages and can be expanded in inflammatory conditions. We analyzed expression of CC chemokine receptors (CCR) in CD14 ؉ CD16 ؉ versus CD14 ؉؉ monocytes, which may be crucial for specific trafficking. Multicolor flow cytometric analysis of whole peripheral blood revealed that, as opposed to CD14 ؉؉ monocytes, the CD14 ؉ CD16 ؉ subset lacked surface expression of monocyte chemotactic protein-1 (MCP-1) receptor CCR2, however, it showed significantly higher surface expression of the macrophage inflammatory protein 1␣ (MIP-1␣)/RANTES receptor CCR5. This was paralleled by differences in mRNA expression in the subsets, as shown by reverse transcriptase-polymerase chain reaction using sorted cells. In comparison to CD14 ؉؉ monocytes, CD14 ؉ CD16 ؉ cells expressed lower CCR2 but higher CCR5 transcript levels, whereas CCR1 levels were equivalent. Flow cytometric analysis of isolated human monocytes recovered after transendothelial chemotaxis assays revealed that the percentage of CD14 ؉ CD16 ؉ cells was dramatically reduced in the fraction migrating toward MCP-1 compared with the fraction that did not migrate or the input, showing that polarized CCR2 expression was accompanied by a differential chemotactic responsiveness. Moreover, CD11b surface expression was preferentially up-regulated by MCP-1 in CD14 ؉؉ cells but by MIP-1␣ in CD14 ؉ CD16 ؉ monocytes, confirming the functional relevance of distinct CCR expression. The characteristics of CD14 ؉ CD16 ؉ cells may reflect preactivation by cytokines and determine their predilective localization during specific inflammatory conditions or susceptibility to infection. J. Leukoc. Biol. 67: 699-704; 2000.

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Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Differential chemokine receptor expression and function in human monocyte subpopulations

Weber

Belge

Hundelshausen

et al. 2000

Journal of Leukocyte Biology

339

250

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“…Differences in the amount of RNA loaded may account for the relatively less dramatic induction of CCR2 mRNA expression after normalization in Figure 2B. Because CCR2 mRNA in monocytes is downregulated by inflammatory cytokines, 18,19 this excludes potential contaminations with monocyte mRNA. Hence this demonstrates that human endothelial cells express inducible mRNA for the MCP-1 receptor CCR2.…”

Section: Expression Of Ccr2 Mrna In Endothelial Cellsmentioning

confidence: 99%

Expression of CCR2 by Endothelial Cells

Weber¹,

Nelson²,

Gröne³

et al. 1999

ATVB

260

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Abstract-Endothelial cell proliferation and migration may play a central role in angiogenesis, wound healing, and atherosclerosis. Although CXC chemokines can act on endothelial cells by influencing proliferation, an involvement of CC chemokines and endothelial expression of chemokine receptors remains to be elucidated. Reverse transcriptionpolymerase chain reaction, RNase protection, Western blot, and flow cytometric analysis showed that human umbilical vein endothelial cells express mRNA and surface protein of the monocyte chemotactic protein-1 (MCP-1) receptor CCR2, which was upregulated by inflammatory cytokines. MCP-1 induced migration of endothelial cells in a transwell assay, which was inhibited by the 9-76 MCP-1 receptor antagonist. Increased secretion of MCP-1 or interleukin-8, but not RANTES, on endothelial injury suggested a functional role of CCR2 in wound repair as measured by ELISA. After mechanical injury to endothelial monolayers, which spontaneously closed within 24 hours, wound repair was delayed by the 9-76 antagonist and by a blocking monoclonal antibody to MCP-1, but not to interleukin-8, and was improved by exogenous MCP-1. This was confirmed by quantification of cell migration into the wound area, whereas proliferation and viability were unaltered by MCP-1 or its analogue. Notably, immunohistochemistry of inflamed tissue revealed CCR2 staining on arterial, venous, and venular endothelium affected by cellular infiltration. This is the first demonstration of endothelial CCR2 expression ex vivo, inferring its involvement in inflammatory conditions. Thus endothelial cells express functional CCR2 that may have important implications for endothelial wound repair and inflammatory reactions.

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“…Recent studies in our laboratory demonstrated that pro-inflammatory cytokines including MCP-1 itself rapidly down-regulated the expression of CCR2, which may aid the retention of monocytes at sites of inflammation after their recruitment from the circulation (16). These cytokines also induced the secretion of MCP-1 by monocytes and initiated the switch from the MCP-1-responsive state to the MCP-1-unresponsive state, which coincided with the loss of CCR2.…”

mentioning

confidence: 96%

“…Equilibrium Binding Analysis-Binding assays were performed essentially as described previously (16). Briefly, the cells were washed with PBS and 0.3 ϫ 10 6 cells were suspended in 100 l of RPMI 1640 containing 0.5% BSA.…”

Section: Materials-hekmentioning

confidence: 99%

Role of the First Extracellular Loop in the Functional Activation of CCR2

Han

Green

Tangirala

et al. 1999

Journal of Biological Chemistry

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The physiological cellular responses to monocyte chemoattractant protein-1 (MCP-1), a potent chemotactic and activating factor for mononuclear leukocytes, are mediated by specific binding to CCR2. The aim of this investigation is to identify receptor microdomains that are involved in high affinity agonist binding and receptor activation. The results from our functional studies in which we utilized neutralizing antisera against CCR2 are consistent with a multidomain binding model, previously proposed by others. The first extracellular loop was of particular interest, because in addition to a ligand-binding domain it contained also information for receptor activation, crucial for transmembrane signaling. Replacement of the first extracellular loop of CCR2 with the corresponding region of CCR1 decreased the MCP-1 binding affinity about 10-fold and prevented transmembrane signaling. A more detailed analysis by site-directed mutagenesis revealed that this receptor segment contains two distinct microdomains. The amino acid residues Asn 104 and Glu 105 are essential for high affinity agonist binding but are not involved in receptor activation. In contrast, the charged amino acid residue His 100 does not contribute to ligand binding but is vital for receptor activation and initiation of transmembrane signaling. We hypothesize that the interaction of agonist with this residue initiates the conformational switch that allows the formation of the functional CCR2-G protein complex.

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Regulation of Expression of the Human Monocyte Chemotactic Protein-1 Receptor (hCCR2) by Cytokines

Cited by 106 publications

References 47 publications

Differential chemokine receptor expression and function in human monocyte subpopulations

Differential chemokine receptor expression and function in human monocyte subpopulations

Expression of CCR2 by Endothelial Cells

Role of the First Extracellular Loop in the Functional Activation of CCR2

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