Fractalkine/CX3CL1 production by human airway smooth muscle cells: induction by IFN-gamma and TNF-alpha and regulation by TGF-beta and corticosteroids.
Chemokine synthesis by airway smooth muscle cells (ASMC) may be an important process underlying inflammatory cell recruitment in airway inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Fractalkine (FKN) is a recently described CX(3)C chemokine that has dual functions, serving as both a cell adhesion molecule and a chemoattractant for monocytes and T cells, expressing its unique receptor, CX(3)CR1. We investigated FKN expression by human ASMC in response to the proinflammatory cytokines IL-1beta, TNF-alpha, and IFN-gamma, the T helper 2-type cytokines IL-4, IL-10, and IL-13, and the fibrogenic cytokine transforming growth factor (TGF)-beta. Neither of these cytokines alone had any significant effect on ASMC FKN production. Combined stimulation with IFN-gamma and TNF-alpha induced FKN mRNA and protein expression in a time- and concentration-dependent manner. TGF-beta had a significant inhibitory effect on cytokine-induced FKN mRNA and protein expression. Dexamethasone (10(-8)-10(-6) M) significantly upregulated cytokine-induced FKN mRNA and protein expression. Finally, we used selective inhibitors of the mitogen-activated protein kinases c-Jun NH(2)-terminal kinase (JNK) (SP-610025), p38 (SB-203580), and extracellular signal-regulated kinase (PD-98095) to investigate their role in FKN production. SP-610025 (25 microM) and SB-203580 (20 microM), but not PD-98095, significantly attenuated cytokine-induced FKN protein synthesis. IFN-gamma- and TNF-alpha-induced JNK phosphorylation remained unaltered in the presence of TGF-beta but was inhibited by dexamethasone, indicating that JNK is not involved in TGF-beta- or dexamethasone-mediated regulation of FKN production. In summary, FKN production by human ASMC in vitro is regulated by inflammatory and anti-inflammatory factors.
Department of Thoracic Medicine, National Heart and Lung Institute, Imperial College, London, Dovehouse St., SW3 6LY, London, UK.
Maria B
MB
Sukkar
Razao
R
Issa
Shaoping
S
Xie
Ute
U
Oltmanns
Robert
R
Newton
Kian Fan
KF
Chung
D000305:Adrenal Cortex Hormones / Q000494:pharmacology; D001483:Base Sequence; D001980:Bronchi / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D054428:Chemokine CX3CL1; D020523:Chemokines, CX3C / Q000235:genetics*; D017931:DNA Primers; D003609:Dactinomycin / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D007700:Kinetics; D048670:MAP Kinase Kinase 4; D008565:Membrane Proteins / Q000235:genetics*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016133:Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D000305:Adrenal Cortex Hormones; C515538:CX3CL1 protein, human; D054428:Chemokine CX3CL1; D020523:Chemokines, CX3C; D017931:DNA Primers; D008565:Membrane Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D003609:Dactinomycin; D007371:Interferon-gamma; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases