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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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Effects of chemokines on [Ca2+]i in monocytes cultured in  the absence (M) or presence (M + M-CSF) of M-CSF. Fura-2–labeled  cells were exposed (at the times indicated by arrowheads) to chemically  synthesized RANTES variants (100 nM) or other indicated rh chemokines (30 nM; R & D Systems), and Ca2+ responses were measured. The  final concentrations of chemokines in this and subsequent experiments  were sufficient to induce a maximal increase in [Ca2+]i in the responding  cells, and further challenge with the same dose produced little or no detectable change in [Ca2+]i. The duration (∼100 s) and amplitude (∼20– 30% of Fura-2 saturation) of Ca2+ responses were similar to those obtained for chemokines with human monocytes (36). Similar results were  obtained in two additional experiments.
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Figure 4: Effects of chemokines on [Ca2+]i in monocytes cultured in the absence (M) or presence (M + M-CSF) of M-CSF. Fura-2–labeled cells were exposed (at the times indicated by arrowheads) to chemically synthesized RANTES variants (100 nM) or other indicated rh chemokines (30 nM; R & D Systems), and Ca2+ responses were measured. The final concentrations of chemokines in this and subsequent experiments were sufficient to induce a maximal increase in [Ca2+]i in the responding cells, and further challenge with the same dose produced little or no detectable change in [Ca2+]i. The duration (∼100 s) and amplitude (∼20– 30% of Fura-2 saturation) of Ca2+ responses were similar to those obtained for chemokines with human monocytes (36). Similar results were obtained in two additional experiments.

Mentions: Transient changes in the cytosolic free Ca2+ concentration ([Ca2+]i) were recorded after stimulation of monocytes or macrophages with an optimal concentration of RANTES- (1–68) or RANTES(3–68), and the effects were compared with those of other chemokines (Fig. 4). Addition of 100 nM RANTES(1–68) to cells loaded with the fluorescent Ca2+ probe Fura-2 induced a rapid increase in [Ca2+]i in both monocytes and macrophages. In contrast, the same concentration of RANTES(3–68) increased [Ca2+]i in macrophages but not in monocytes. Among the other chemo-kines tested, macrophage inflammatory protein (MIP)–1α, MCP-1, MCP-3 (1, 6), and stromal-derived factor–1β (SDF-1β; references 18–20) also increased [Ca2+]i in resting monocytes, whereas MCP-2 (21) induced a barely detectable response and MIP-1β (1, 6) was inactive. On the basis of the previously described receptor specificities of these chemokines (1, 6, 19, 20), the obtained activity pattern is consistent with expression of CCR1, CCR2b, and CXCR4 receptors on monocytes (Fig. 3). Macrophages showed marked Ca2+ responses to MIP-1α, MIP-1β, MCP-2, MCP-3, and SDF-1β, but were resistant to MCP-1, consistent with the presence of transcripts encoding CCR1, CCR5, and CXCR4, and the absence of those encoding CCR2b, in these cells (Fig. 3).


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)

Effects of chemokines on [Ca2+]i in monocytes cultured in  the absence (M) or presence (M + M-CSF) of M-CSF. Fura-2–labeled  cells were exposed (at the times indicated by arrowheads) to chemically  synthesized RANTES variants (100 nM) or other indicated rh chemokines (30 nM; R & D Systems), and Ca2+ responses were measured. The  final concentrations of chemokines in this and subsequent experiments  were sufficient to induce a maximal increase in [Ca2+]i in the responding  cells, and further challenge with the same dose produced little or no detectable change in [Ca2+]i. The duration (∼100 s) and amplitude (∼20– 30% of Fura-2 saturation) of Ca2+ responses were similar to those obtained for chemokines with human monocytes (36). Similar results were  obtained in two additional experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199148&req=5

Figure 4: Effects of chemokines on [Ca2+]i in monocytes cultured in the absence (M) or presence (M + M-CSF) of M-CSF. Fura-2–labeled cells were exposed (at the times indicated by arrowheads) to chemically synthesized RANTES variants (100 nM) or other indicated rh chemokines (30 nM; R & D Systems), and Ca2+ responses were measured. The final concentrations of chemokines in this and subsequent experiments were sufficient to induce a maximal increase in [Ca2+]i in the responding cells, and further challenge with the same dose produced little or no detectable change in [Ca2+]i. The duration (∼100 s) and amplitude (∼20– 30% of Fura-2 saturation) of Ca2+ responses were similar to those obtained for chemokines with human monocytes (36). Similar results were obtained in two additional experiments.
Mentions: Transient changes in the cytosolic free Ca2+ concentration ([Ca2+]i) were recorded after stimulation of monocytes or macrophages with an optimal concentration of RANTES- (1–68) or RANTES(3–68), and the effects were compared with those of other chemokines (Fig. 4). Addition of 100 nM RANTES(1–68) to cells loaded with the fluorescent Ca2+ probe Fura-2 induced a rapid increase in [Ca2+]i in both monocytes and macrophages. In contrast, the same concentration of RANTES(3–68) increased [Ca2+]i in macrophages but not in monocytes. Among the other chemo-kines tested, macrophage inflammatory protein (MIP)–1α, MCP-1, MCP-3 (1, 6), and stromal-derived factor–1β (SDF-1β; references 18–20) also increased [Ca2+]i in resting monocytes, whereas MCP-2 (21) induced a barely detectable response and MIP-1β (1, 6) was inactive. On the basis of the previously described receptor specificities of these chemokines (1, 6, 19, 20), the obtained activity pattern is consistent with expression of CCR1, CCR2b, and CXCR4 receptors on monocytes (Fig. 3). Macrophages showed marked Ca2+ responses to MIP-1α, MIP-1β, MCP-2, MCP-3, and SDF-1β, but were resistant to MCP-1, consistent with the presence of transcripts encoding CCR1, CCR5, and CXCR4, and the absence of those encoding CCR2b, in these cells (Fig. 3).

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