TY - JOUR
T1 - Hyaluronic Acid or TNF-α Plus Fibronectin Triggers Granulocyte Macrophage-Colony-Stimulating Factor mRNA Stabilization in Eosinophils Yet Engages Differential Intracellular Pathways and mRNA Binding Proteins
AU - Esnault, Stéphane
AU - Malter, James S.
PY - 2003/12/15
Y1 - 2003/12/15
N2 - Eosinophils (Eos) accumulate in airways and lung parenchyma of active asthmatics. GM-CSF is a potent inhibitor of Eos apoptosis both in vitro and in vivo and is produced by activated fibroblasts, mast cells, T lymphocytes as well as Eos. Cytokine release by Eos is preceded by GM-CSF mRNA stabilization induced by TNF-α plus fibronectin. Hyaluronic acid (HA) is a major extracellular matrix proteoglycan, which also accumulates in the lung during asthma exacerbations. In this study we have analyzed the effects of HA on Eos survival and GM-CSF expression. We demonstrate that like TNF-α plus fibronectin, HA stabilizes GM-CSF mRNA, increases GM-CSF secretion, and prolongs in vitro Eos survival. GM-CSF mRNA stabilization accounts for most of the observed GM-CSF mRNA accumulation and protein production. Unlike TNF-α plus fibronectin, GM-CSF mRNA stabilization induction by HA requires continuous extracellular signal-regulated kinase phosphorylation. Finally, to identify potential protein regulators responsible for GM-CSF mRNA stabilization, immunoprecipitation-RT-PCR studies revealed increased GM-CSF mRNA associated with YB-1, HuR, and heterogeneous nuclear ribonucleoprotein (hnRNP) C after TNF-α plus fibronectin but only hnRNP C after HA. Thus, our data suggest that both TNF-α plus fibronectin and HA, which are relevant physiological effectors in asthma, contributes to long-term Eos survival in vivo by enhancing GM-CSF production through two different posttranscriptional regulatory pathways involving extracellular signal-regulated kinase phosphorylation and RNA binding proteins YB-1, HuR, and hnRNP C.
AB - Eosinophils (Eos) accumulate in airways and lung parenchyma of active asthmatics. GM-CSF is a potent inhibitor of Eos apoptosis both in vitro and in vivo and is produced by activated fibroblasts, mast cells, T lymphocytes as well as Eos. Cytokine release by Eos is preceded by GM-CSF mRNA stabilization induced by TNF-α plus fibronectin. Hyaluronic acid (HA) is a major extracellular matrix proteoglycan, which also accumulates in the lung during asthma exacerbations. In this study we have analyzed the effects of HA on Eos survival and GM-CSF expression. We demonstrate that like TNF-α plus fibronectin, HA stabilizes GM-CSF mRNA, increases GM-CSF secretion, and prolongs in vitro Eos survival. GM-CSF mRNA stabilization accounts for most of the observed GM-CSF mRNA accumulation and protein production. Unlike TNF-α plus fibronectin, GM-CSF mRNA stabilization induction by HA requires continuous extracellular signal-regulated kinase phosphorylation. Finally, to identify potential protein regulators responsible for GM-CSF mRNA stabilization, immunoprecipitation-RT-PCR studies revealed increased GM-CSF mRNA associated with YB-1, HuR, and heterogeneous nuclear ribonucleoprotein (hnRNP) C after TNF-α plus fibronectin but only hnRNP C after HA. Thus, our data suggest that both TNF-α plus fibronectin and HA, which are relevant physiological effectors in asthma, contributes to long-term Eos survival in vivo by enhancing GM-CSF production through two different posttranscriptional regulatory pathways involving extracellular signal-regulated kinase phosphorylation and RNA binding proteins YB-1, HuR, and hnRNP C.
UR - http://www.scopus.com/inward/record.url?scp=0346366983&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0346366983&partnerID=8YFLogxK
U2 - 10.4049/jimmunol.171.12.6780
DO - 10.4049/jimmunol.171.12.6780
M3 - Article
C2 - 14662883
AN - SCOPUS:0346366983
SN - 0022-1767
VL - 171
SP - 6780
EP - 6787
JO - Journal of Immunology
JF - Journal of Immunology
IS - 12
ER -