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Regulation of the receptor specificity and function of the chemokine RANTES (regulated on activation, normal T cell expressed and secreted) by dipeptidyl peptidase IV (CD26)-mediated cleavage.

Oravecz T, Pall M, Roderiquez G, Gorrell MD, Ditto M, Nguyen NY, Boykins R, Unsworth E, Norcross MA - J. Exp. Med. (1997)

Bottom Line: The truncated RANTES(3-68) lacked the ability of native RANTES(1-68) to increase the cytosolic calcium concentration in human monocytes, but still induced this response in macrophages activated with macrophage colony-stimulating factor.Analysis of chemokine receptor messenger RNAs and patterns of desensitization of chemokine responses showed that the differential activity of the truncated molecule results from an altered receptor specificity.Our results indicate that CD26-mediated processing together with cell activation-induced changes in receptor expression provides an integrated mechanism for differential cell recruitment and for the regulation of target cell specificity of RANTES, and possibly other chemokines.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematologic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA. tamas@helix.nih.gov

ABSTRACT
CD26 is a leukocyte activation marker that possesses dipeptidyl peptidase IV activity but whose natural substrates and immunological functions have not been clearly defined. Several chemo-kines, including RANTES (regulated on activation, normal T cell expressed and secreted), have now been shown to be substrates for recombinant soluble human CD26. The truncated RANTES(3-68) lacked the ability of native RANTES(1-68) to increase the cytosolic calcium concentration in human monocytes, but still induced this response in macrophages activated with macrophage colony-stimulating factor. Analysis of chemokine receptor messenger RNAs and patterns of desensitization of chemokine responses showed that the differential activity of the truncated molecule results from an altered receptor specificity. RANTES(3-68) showed a reduced activity, relative to that of RANTES(1-68), with cells expressing the recombinant CCR1 chemokine receptor, but retained the ability to stimulate CCR5 receptors and to inhibit the cytopathic effects of HIV-1. Our results indicate that CD26-mediated processing together with cell activation-induced changes in receptor expression provides an integrated mechanism for differential cell recruitment and for the regulation of target cell specificity of RANTES, and possibly other chemokines.

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Desensitization of chemokine-induced Ca2+ responses by  full-length or truncated RANTES. Fura-2–labeled cells were stimulated  first with 100 nM RANTES(1–68) or RANTES(3–68), or were left unstimulated. After ∼150 s, the cells were challenged with the RANTES  variants (100 nM) or other chemokines (30 nM) as indicated, and Ca2+  responses were measured.
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Figure 5: Desensitization of chemokine-induced Ca2+ responses by full-length or truncated RANTES. Fura-2–labeled cells were stimulated first with 100 nM RANTES(1–68) or RANTES(3–68), or were left unstimulated. After ∼150 s, the cells were challenged with the RANTES variants (100 nM) or other chemokines (30 nM) as indicated, and Ca2+ responses were measured.

Mentions: Agonists that act at common chemokine receptors block each other's activity as a result of receptor desensitization, whereas responses to chemokines that act at different receptors generally are not affected (1, 6). Therefore, we performed comparative desensitization experiments to define the types of receptors that mediate the effects of native versus truncated RANTES in macrophages (Fig. 5). Macrophages that were stimulated first with 100 nM RANTES(1–68) did not exhibit a second Ca2+ response when challenged with the same dose of either full-length or truncated RANTES. In contrast, cells stimulated with 100 nM RANTES(3–68) fully retained their ability to respond to a subsequent challenge with full-length RANTES, but were desensitized to the effect of the truncated form. These results suggest that the receptor repertoire available for truncated RANTES is more restricted than that available for the native chemokine. To further characterize the receptor usage of the different forms of RANTES and other chemokines, we also studied the sensitivity of MIP-1β–, MCP-3–, and SDF-1β–induced Ca2+ responses to RANTES-mediated receptor desensitization (Fig. 5). Of the known receptors, RANTES signals via CCR1, CCR4, and CCR5, whereas MIP-1β acts at CCR5 exclusively and MCP-3 binds only to CCR1 and CCR2b at the concentrations used in our experiments (1, 6). The only receptor known to bind SDF-1β is CXCR4 (19, 20). Pretreatment of macrophages with full-length RANTES blocked the ability of MIP-1β and MCP-3, but not that of SDF-1β, to increase [Ca2+]i. In contrast, RANTES(3–68) desensitized cells to the effect of MIP-1β but did not affect the response to MCP-3 or SDF-1β. These results are consistent with previous data on RANTES-induced receptor desensitization (1) and with our data on chemokine receptor mRNA abundance (Fig. 3). They suggest that, in M-CSF–activated macrophages, full-length RANTES shares CCR1 and CCR5 receptors with MCP-3 and MIP-1β, respectively. Our results also indicate that, without its two NH2-terminal residues, RANTES is still able to signal via CCR5 but can no longer act at the CCR1 receptor.


Regulation of the receptor specificity and function of the chemokine RANTES (regulated on activation, normal T cell expressed and secreted) by dipeptidyl peptidase IV (CD26)-mediated cleavage.

Oravecz T, Pall M, Roderiquez G, Gorrell MD, Ditto M, Nguyen NY, Boykins R, Unsworth E, Norcross MA - J. Exp. Med. (1997)

Desensitization of chemokine-induced Ca2+ responses by  full-length or truncated RANTES. Fura-2–labeled cells were stimulated  first with 100 nM RANTES(1–68) or RANTES(3–68), or were left unstimulated. After ∼150 s, the cells were challenged with the RANTES  variants (100 nM) or other chemokines (30 nM) as indicated, and Ca2+  responses were measured.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2199148&req=5

Figure 5: Desensitization of chemokine-induced Ca2+ responses by full-length or truncated RANTES. Fura-2–labeled cells were stimulated first with 100 nM RANTES(1–68) or RANTES(3–68), or were left unstimulated. After ∼150 s, the cells were challenged with the RANTES variants (100 nM) or other chemokines (30 nM) as indicated, and Ca2+ responses were measured.
Mentions: Agonists that act at common chemokine receptors block each other's activity as a result of receptor desensitization, whereas responses to chemokines that act at different receptors generally are not affected (1, 6). Therefore, we performed comparative desensitization experiments to define the types of receptors that mediate the effects of native versus truncated RANTES in macrophages (Fig. 5). Macrophages that were stimulated first with 100 nM RANTES(1–68) did not exhibit a second Ca2+ response when challenged with the same dose of either full-length or truncated RANTES. In contrast, cells stimulated with 100 nM RANTES(3–68) fully retained their ability to respond to a subsequent challenge with full-length RANTES, but were desensitized to the effect of the truncated form. These results suggest that the receptor repertoire available for truncated RANTES is more restricted than that available for the native chemokine. To further characterize the receptor usage of the different forms of RANTES and other chemokines, we also studied the sensitivity of MIP-1β–, MCP-3–, and SDF-1β–induced Ca2+ responses to RANTES-mediated receptor desensitization (Fig. 5). Of the known receptors, RANTES signals via CCR1, CCR4, and CCR5, whereas MIP-1β acts at CCR5 exclusively and MCP-3 binds only to CCR1 and CCR2b at the concentrations used in our experiments (1, 6). The only receptor known to bind SDF-1β is CXCR4 (19, 20). Pretreatment of macrophages with full-length RANTES blocked the ability of MIP-1β and MCP-3, but not that of SDF-1β, to increase [Ca2+]i. In contrast, RANTES(3–68) desensitized cells to the effect of MIP-1β but did not affect the response to MCP-3 or SDF-1β. These results are consistent with previous data on RANTES-induced receptor desensitization (1) and with our data on chemokine receptor mRNA abundance (Fig. 3). They suggest that, in M-CSF–activated macrophages, full-length RANTES shares CCR1 and CCR5 receptors with MCP-3 and MIP-1β, respectively. Our results also indicate that, without its two NH2-terminal residues, RANTES is still able to signal via CCR5 but can no longer act at the CCR1 receptor.

Bottom Line: The truncated RANTES(3-68) lacked the ability of native RANTES(1-68) to increase the cytosolic calcium concentration in human monocytes, but still induced this response in macrophages activated with macrophage colony-stimulating factor.Analysis of chemokine receptor messenger RNAs and patterns of desensitization of chemokine responses showed that the differential activity of the truncated molecule results from an altered receptor specificity.Our results indicate that CD26-mediated processing together with cell activation-induced changes in receptor expression provides an integrated mechanism for differential cell recruitment and for the regulation of target cell specificity of RANTES, and possibly other chemokines.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematologic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA. tamas@helix.nih.gov

ABSTRACT
CD26 is a leukocyte activation marker that possesses dipeptidyl peptidase IV activity but whose natural substrates and immunological functions have not been clearly defined. Several chemo-kines, including RANTES (regulated on activation, normal T cell expressed and secreted), have now been shown to be substrates for recombinant soluble human CD26. The truncated RANTES(3-68) lacked the ability of native RANTES(1-68) to increase the cytosolic calcium concentration in human monocytes, but still induced this response in macrophages activated with macrophage colony-stimulating factor. Analysis of chemokine receptor messenger RNAs and patterns of desensitization of chemokine responses showed that the differential activity of the truncated molecule results from an altered receptor specificity. RANTES(3-68) showed a reduced activity, relative to that of RANTES(1-68), with cells expressing the recombinant CCR1 chemokine receptor, but retained the ability to stimulate CCR5 receptors and to inhibit the cytopathic effects of HIV-1. Our results indicate that CD26-mediated processing together with cell activation-induced changes in receptor expression provides an integrated mechanism for differential cell recruitment and for the regulation of target cell specificity of RANTES, and possibly other chemokines.

Show MeSH
Related in: MedlinePlus