Granulocyte-Macrophage Colony Stimulating Factor Up-Regulates CCR1 in Human Neutrophils

Abstract

Neutrophils (polymorphonuclear leukocytes; PMN) are phagocytic cells instrumental in the clearance of infectious pathogens. Human PMN are commonly thought to respond primarily to chemokines from the CXC family. However, recent findings suggest that under specific cytokine activation conditions, PMN can also respond to some CC chemokines. In this study, the effect of GM-CSF, a well-characterized PMN priming and maturation factor, on CC-chemokine receptor (CCR) expression in PMN was investigated. Constitutive expression of CCR1 and CCR3 mRNA in PMN was detected by ribonuclease protection assay. Following incubation of PMN with GM-CSF (0.01–10 ng/ml; 6 h) CCR1 mRNA expression was rapidly (∼1 h) up-regulated. In contrast, no significant induction of CCR2, CCR3, CCR4, or CCR5 mRNA was observed. CCR1 protein was also up-regulated by GM-CSF stimulation. GM-CSF-induced up-regulation of CCR1 showed functional consequences because GM-CSF-treated PMN, but not control cells, responded to the CC chemokines macrophage inflammatory protein-1α, monocyte chemoattractant protein-3, and RANTES in assays of chemotactic migration and intracellular calcium mobilization. These results suggest that PMN activated by the proinflammatory cytokine GM-CSF can change their receptor expression pattern and become responsive to CC chemokines.

Proteolytic Activation of Alternative CCR1 Ligands in Inflammation

“…Due to its potency, the NC6* form of CCL15/MIP-1␦ was functional on human neutrophils, which are poorly responsive to CCL3/ MIP-1␣ (14,15) or CCL5/RANTES (14) in vitro. The specificity of CCR1 use on the neutrophils was confirmed by pretreating the cells with a CCR1-specific, small-molecule antagonist or with high concentrations of CCL3/MIP-1␣.…”

Intrapulmonary Expression of Macrophage Inflammatory Protein 1α (CCL3) Induces Neutrophil and NK Cell Accumulation and Stimulates Innate Immunity in Murine Bacterial Pneumonia

“…Interestingly, resting human neutrophils express low levels of CCR1 at baseline and fail to migrate in response to MIP-1␣ (3,36). However, treatment with IFN-␥ or granulocyte-macrophage colony-stimulating factor can dramatically increase CCR1 expression, as well as calcium flux and chemotactic responses to MIP-1␣ (3,6). In vivo, the inhibition of MIP-1␣ or deficiency of CCR1 has been shown to attenuate the recruitment of neutrophils to the lung in rodents in response to i.t.…”

“…K. pneumoniae strain 43816, serotype 2, was obtained from the American Type Culture Collection (Rockville, Md.). For infection, bacteria were grown to stationary phase (18 h) in tryptic soy broth (Soybean-Casein digest; Difco, Detroit, Mich.) in a vented 50-ml conical tube at 37°C, 5% CO 2 (6). The concentration of bacteria in broth was determined by measuring the amount of absorbance at 600 nm on a DU-64 Spectrophotometer (Beckman Instruments Inc., Fullerton, Calif.) and was compared to a standard curve of absorbance.…”

Quantum Proteolytic Activation of Chemokine CCL15 by Neutrophil Granulocytes Modulates Mononuclear Cell Adhesiveness

“…Values are the mean for at least three independent determinations. and increase their receptiveness to CCR1 and CCR3 ligands (2,92,93). Processing of CCL15 by neutrophils is locally limited to the close proximity of the cells by immediate inactivation of cathepsin G and elastase by blood-derived protease inhibitors.…”