RSV-infected airway epithelial cells cause biphasic up-regulation of CCR1 expression on human monocytes.
Respiratory syncytial virus (RSV) infection can cause extensive airway inflammation, which is orchestrated by chemokines and their receptors. RSV-infected epithelial cells secrete many cytokines and chemokines, but little is known about regulation of chemokine receptors on target cells. We investigated the effects of conditioned media (CM) from RSV-infected epithelial cells on monocyte CCR1, CCR2, and CCR5 expression. RSV-CM but not control-CM stimulated a biphasic increase in cell-surface CCR1, and levels peaked at 36 h and 96 h poststimulation. Similar CCR1 up-regulation occurred on monocyte-derived macrophages. Cytochlasin D and colchicine blocked both peaks of expression, demonstrating requirement of a functional cytoskeleton. Intracellular staining revealed little internal sequestration of CCR1 protein, and CCR1 up-regulation was inhibited by actinomycin D and cycloheximide, indicating that both waves of RSV-CM-induced surface CCR1 expression were dependent on de novo transcription and protein synthesis. Cytokine-neutralizing experiments showed that the effects of RSV-CM were decreased by blocking TNF-alpha (percent inhibition=51+/-2.3% at 36 h peak and 42+/-7.7% at 96 h peak) and to a lesser extent, IL-1 (percent inhibition=32+/-7.2% at 36 h and 23+/-2.9% at 96 h). In summary, RSV-CM causes a biphasic up-regulation of surface CCR1 on monocytes, which is dependent on an intact cytoskeleton, requires new gene transcription and protein synthesis, and is mediated in part by the proinflammatory cytokines TNF-alpha and IL-1.
Morrison
Paul T
PT
Department of Infectious Diseases and Immunity, Imperial College, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.
Thomas
Lynette H
LH
Sharland
Mike
M
Friedland
Jon S
JS
D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D003513:Cycloheximide / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism* / Q000821:virology; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology; D008264:Macrophages / Q000276:immunology / Q000821:virology; D009000:Monocytes / Q000378:metabolism*; D054389:Receptors, CCR1; D054390:Receptors, CCR2; D054397:Receptors, CCR3; D019707:Receptors, Chemokine / Q000096:biosynthesis* / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism*; D012136:Respiratory Syncytial Viruses / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D015854:Up-Regulation
C515300:CCR1 protein, human; C515334:CCR2 protein, human; C515350:CCR3 protein, human; D017077:Culture Media, Conditioned; D007375:Interleukin-1; D054389:Receptors, CCR1; D054390:Receptors, CCR2; D054397:Receptors, CCR3; D019707:Receptors, Chemokine; D014409:Tumor Necrosis Factor-alpha; D003609:Dactinomycin; D015638:Cytochalasin D; D003513:Cycloheximide