C3a receptor on dibutyryl-cAMP-differentiated U937 cells and human neutrophils: The human C3a receptor characterized by functional responses and 125I-C3a binding

Klos, Andreas; Bank, Stephanie; Gietz, Claudia; Bautsch, Wilfried; Köhl, Jörg; Burg, M.P.M. van der; Kretzschmar, Titus

doi:10.1021/bi00161a003

Cited by 78 publications

(81 citation statements)

References 30 publications

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“…In addition, we found that pertussis toxin inhibited all C5a-stimulated cell responscs (Dobos et al, 1992). Rcccntly, Klos et al (1992) reported that C3a triggered CaZc transients in U937 cells and in neutrophils and stimulated formation of inositol trisphosphate in U937 cells. Again, pertussis toxin treatment inhibited C3a-stimulated Ca'+ transients (Klos et al 1992).…”

Section: Discussionmentioning

confidence: 98%

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Complement fragment C3a stimulates Ca²⁺ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

Norgauer

Dobos

Kownatzki

et al. 1993

European Journal of Biochemistry

111

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The signal pathways of neutrophils following stimulation with the complement fragment C3a (C3a) were studied in neutrophils and compared to the pathways activated by complement fragment C5a (C5a). Analysis of polyphosphoinositol lipid turnover showed that C5a, but not C3a, activated phosphatidylinositol‐bisphosphate‐3‐kinase (PtdInsP2 3‐kinase) indicating that different signal pathways are activated by the two anaphylatoxins. To examine whether C3a stimulated Ca2+ transients, cytosolic free Ca2+ levels were analyzed in Fluo‐3‐labelled neutrophils by flow cytometry. C3a stimulated a fast and concentration‐dependent increase of cytosolic free Ca2+. Comparison of the C3a response with that of C5a revealed a more pronounced C5a‐triggered Ca2+ rise. Addition of EGTA to the extracellular buffer prior to stimulation did not significantly alter the initial Ca2+ rise at low C5a concentrations, but reduced the time course of the Ca2+ transients at high concentrations. In marked contrast, EGTA completely blocked the Ca2+ response stimulated by C3a in neutrophils labeled with either Indo‐1/AM or Fluo‐3. Preincubation of neutrophils with pertussis toxin inhibited both C3a‐ and C5a‐stimulated Ca2+ transients, indicating the involvement of guanine‐nucleotide‐binding proteins (G proteins) in these processes. In order to examine whether the C3a receptor is coupled to G proteins, binding of guanosine 5′‐O‐(3‐[35S]thiotriphosphate) ([35S]GTP[S]) to purified neutrophil plasma membranes was studied. Both C3a and C5a stimulated high‐affinity binding of [35S]GTP[S] up to 1.5‐fold and 3‐fold, respectively. These data suggest that the two anaphylatoxins activate pertussis‐toxin‐sensitive G proteins, which then trigger different signal transduction pathways. C3a specifically stimulated Ca2+ influx from the extracellular medium, whereas C5a additionally activated the PtdInsP2 3‐kinase and stimulated Ca2+ mobilization from intracellular stores.

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Section: Discussionmentioning

confidence: 98%

“…Rcccntly, Klos et al (1992) reported that C3a triggered CaZc transients in U937 cells and in neutrophils and stimulated formation of inositol trisphosphate in U937 cells. Again, pertussis toxin treatment inhibited C3a-stimulated Ca'+ transients (Klos et al 1992). These authors concluded that C3a and C5a activate similar signal pathways.…”

Section: Discussionmentioning

confidence: 98%

Complement fragment C3a stimulates Ca²⁺ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

Norgauer

Dobos

Kownatzki

et al. 1993

European Journal of Biochemistry

111

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“…C3aR internalization in MSC, monocytes, and HEK293 cells was determined by confocal microscopy. Monocytes were used for comparison because C3aR activation is best documented for myeloid cells (11,14), and HEK293 cells were used because they are among the most commonly used cells to determine the function of transfected receptors. The different cell types were stimulated with 300 nM C3a or 100 nM C5a for the indicated times and stained as described for each panel.…”

Section: Nuclear Translocation Of the C3ar In C3a-stimulated Mscsmentioning

confidence: 99%

C3a and C5a Are Chemotactic Factors for Human Mesenchymal Stem Cells, Which Cause Prolonged ERK1/2 Phosphorylation

Schraufstätter

DiScipio

Zhao

et al. 2009

The Journal of Immunology

164

136

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Mesenchymal stem cells (MSCs) have a great potential for tissue repair, especially if they can be delivered efficiently to sites of tissue injury. Since complement activation occurs whenever there is tissue damage, the effects of the complement activation products C3a and C5a on MSCs were examined. Both C3a and C5a were chemoattractants for human bone marrow-derived MSCs, which expressed both the C3a receptor (C3aR) and the C5a receptor (C5aR; CD88) on the cell surface. Specific C3aR and C5aR inhibitors blocked the chemotactic response, as did pertussis toxin, indicating that the response was mediated by the known anaphylatoxin receptors in a Gi activation-dependent fashion. While C5a causes strong and prolonged activation of various signaling pathways in many different cell types, the response observed with C3a is generally transient and weak. However, we show herein that in MSCs both C3a and C5a caused prolonged and robust ERK1/2 and Akt phosphorylation. Phospho-ERK1/2 was translocated to the nucleus in both C3a and C5a-stimulated MSCs, which was associated with subsequent phosphorylation of the transcription factor Elk, which could not be detected in other cell types stimulated with C3a. More surprisingly, the C3aR itself was translocated to the nucleus in C3a-stimulated MSCs, especially at low cell densities. Since nuclear activation/translocation of G protein-coupled receptors has been shown to induce long-term effects, this novel observation implies that C3a exerts far-reaching consequences on MSC biology. These results suggest that the anaphylatoxins C3a and C5a present in injured tissues contribute to the recruitment of MSCs and regulation of their behavior.

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“…Binding data were analyzed by iterative curve fitting to one site model. Differentiated U937 cells, which express high levels of C3aR, were used as a positive control (29,31). Differentiated U937 cells showed a high affinity binding of 125 I-C3a, with one binding site of apparent K d equal to 1.1 Ϯ 0.2 nM (Fig.…”

Section: I-c3a Binding Studies Of Human Bm Cd34 ϩ Progenitor Cells Anmentioning

confidence: 99%

Complement C3a Enhances CXCL12 (SDF-1)-Mediated Chemotaxis of Bone Marrow Hematopoietic Cells Independently of C3a Receptor

Honczarenko

Ratajczak

Nicholson‐Weller

et al. 2005

The Journal of Immunology

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Complement C3a promotes CXCL12-induced migration and engraftment of human and murine hemopoietic progenitor cells, suggesting a cross-influence between anaphylatoxin and chemokine axes. Here we have explored the underlying mechanism(s) of complement anaphylatoxin and chemokine cooperation. In addition to C3a, C3a-desArg and C4a but not C5a, are potent enhancers of CXCL12-induced chemotaxis of human and murine bone marrow (BM) stem/progenitor cells and B lineage cells. C3a enhancement of chemotaxis is chemokine specific because it is also observed for chemotaxis to CCL19 but not to CXCL13. The potentiating effect of C3a on CXCL12 is independent of the classical C3a receptor (C3aR). First, human BM CD34+ and B lineage cells do not express C3aR by flow cytometry. Second, the competitive C3aR inhibitor SB290157 does not affect C3a-mediated enhancement of CXCL12-induced chemotaxis. Third, enhancement of chemotaxis of hemopoietic cells is also mediated by C3a-desArg, which does not bind to C3aR. Finally, C3a enhances CXCL12-induced chemotaxis of BM cells from C3aR knockout mice similar to BM cells from wild-type mice. Subsequent studies revealed that C3a increased the binding affinity of CXCL12 to human CXCR4+/C3aR−, REH pro-B cells, which is compatible with a direct interaction between C3a and CXCL12. BM stromal cells were able to generate C3a, C3a-desArg, C4a, as well as CXCL12, suggesting that this pathway could function in vivo. Taken together, we demonstrate a C3a-CXCL12 interaction independent of the C3aR, which may provide a mechanism to modulate the function of CXCL12 in the BM microenvironment.

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C3a receptor on dibutyryl-cAMP-differentiated U937 cells and human neutrophils: The human C3a receptor characterized by functional responses and 125I-C3a binding

Cited by 78 publications

References 30 publications

Complement fragment C3a stimulates Ca²⁺ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

Complement fragment C3a stimulates Ca²⁺ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

C3a and C5a Are Chemotactic Factors for Human Mesenchymal Stem Cells, Which Cause Prolonged ERK1/2 Phosphorylation

Complement C3a Enhances CXCL12 (SDF-1)-Mediated Chemotaxis of Bone Marrow Hematopoietic Cells Independently of C3a Receptor

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C3a receptor on dibutyryl-cAMP-differentiated U937 cells and human neutrophils: The human C3a receptor characterized by functional responses and 125I-C3a binding

Cited by 78 publications

References 30 publications

Complement fragment C3a stimulates Ca2+ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

Complement fragment C3a stimulates Ca2+ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

C3a and C5a Are Chemotactic Factors for Human Mesenchymal Stem Cells, Which Cause Prolonged ERK1/2 Phosphorylation

Complement C3a Enhances CXCL12 (SDF-1)-Mediated Chemotaxis of Bone Marrow Hematopoietic Cells Independently of C3a Receptor

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Product

Resources

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Complement fragment C3a stimulates Ca²⁺ influx in neutrophils via a pertussis‐toxin‐sensitive G protein

Complement fragment C3a stimulates Ca²⁺ influx in neutrophils via a pertussis‐toxin‐sensitive G protein