Human lung myofibroblasts as effectors of the inflammatory process: the common receptor gamma chain is induced by Th2 cytokines, and CD40 ligand is induced by lipopolysaccharide, thrombin and TNF-alpha.
The common gamma (gamma c) chain, shared by Th1 and Th2 cytokines, is fundamental for the activation of hematopoietic cells, but its role in non-hematopoietic tissues has not been explored. Here we show that in normal lung fibroblasts IL-4 and IL-13 induce the expression of the gamma c chain and its association with Janus kinase (JAK) 3, while lung myofibroblasts constitutively express a gamma c chain displaying a limited association with JAK3. In the latter cells, without exogenous cytokines, gamma c/JAK3 controls, through autocrine loops, tyrosine kinase (TYK) 2 phosphorylation and the balance between functional (IL-4Ralpha, IL-13Ralpha 1) and decoy (IL-13Ralpha 2) high-affinity receptors. Moreover, JAK3 is also associated with a pre-phosphorylated IL-4Ralpha and CD40. This novel "heterotrimer" (p-IL-4Ralpha, CD40/JAK3) is functional and controls STAT3 phosphorylation and CD40 expression, as shown by use of the specific JAK3 inhibitor WHI-P31. In basal culture conditions, CD40 signaling could be induced by the transient establishment of inter-fibroblastic CD40/CD40 ligand (CD40L) functional bridges. Indeed, powerful pro-inflammatory stimuli such as lipopolysaccharide and thrombin can rapidly mobilize CD40L at the surface of lung myofibroblasts. These interactions are modified by IL-13, which triggers the formation of a new type of functional receptor (p-IL-4Ralpha /IL-13Ralpha 1/gamma c) and also the recruitment and the phosphorylation of JAK3. Treatment with JAK3 inhibitors blocks IL-13-induced phosphorylation of JAK2, TYK2 and STAT3, but not of JAK1 and STAT6. These data underline (1) the pivotal role of the gamma c chain, CD40/CD40L, JAK3 and IL-13 in the inflammatory-like activation of lung myofibroblasts, (2) the cell-type restraint effects of IL-13 on these cells, and (3) the potential usefulness of JAK3 inhibitors in the treatment of asthma.
U506 INSERM, Hôpital Paul Brousse, Villejuif, France.
Christelle
C
Doucet
Julien
J
Giron-Michel
Giorgio Walter
GW
Canonica
Bruno
B
Azzarone
D018927:Anti-Asthmatic Agents / Q000494:pharmacology; D019898:Autocrine Communication; D019013:CD40 Antigens / Q000502:physiology; D023201:CD40 Ligand / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015195:Drug Design; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D053631:Interleukin Receptor Common gamma Subunit; D018793:Interleukin-13 / Q000494:pharmacology*; D053661:Interleukin-13 Receptor alpha1 Subunit; D015847:Interleukin-4 / Q000494:pharmacology*; D053614:Janus Kinase 2; D053616:Janus Kinase 3; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000166:cytology*; D046911:Macromolecular Substances; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000378:metabolism / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D018123:Receptors, Interleukin / Q000145:classification / Q000235:genetics / Q000378:metabolism; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4 / Q000145:classification / Q000235:genetics / Q000378:metabolism; D020395:Receptors, Interleukin-7 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D053634:TYK2 Kinase; D013917:Thrombin / Q000494:pharmacology*; D015534:Trans-Activators / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D018927:Anti-Asthmatic Agents; D019013:CD40 Antigens; D004268:DNA-Binding Proteins; C508181:IL13RA1 protein, human; C507941:IL2RG protein, human; D053631:Interleukin Receptor Common gamma Subunit; D018793:Interleukin-13; D053661:Interleukin-13 Receptor alpha1 Subunit; D008070:Lipopolysaccharides; D046911:Macromolecular Substances; D011506:Proteins; D011518:Proto-Oncogene Proteins; D018123:Receptors, Interleukin; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4; D020395:Receptors, Interleukin-7; D011993:Recombinant Fusion Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D023201:CD40 Ligand; D015847:Interleukin-4; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507933:JAK3 protein, human; D053614:Janus Kinase 2; D053616:Janus Kinase 3; D053634:TYK2 Kinase; C070139:TYK2 protein, human; D013917:Thrombin