Glucocorticoids potentiate IL-6-induced SP-B expression in H441 cells by enhancing the JAK-STAT signaling pathway

Andreas Ladenburger, Matthias Seehase, Boris W. Kramer, Wolfgang Thomas, Johannes Wirbelauer, Christian P. Speer, Steffen Kunzmann*

*Corresponding author for this work

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24 Citations (Web of Science)

Abstract

Ladenburger A, Seehase M, Kramer BW, Thomas W, Wirbelauer J, Speer CP, Kunzmann S. Glucocorticoids potentiate IL-6-induced SP-B expression in H441 cells by enhancing the JAK-STAT signaling pathway. Am J Physiol Lung Cell Mol Physiol 299: L578-L584, 2010. First published August 6, 2010; doi:10.1152/ajplung.00055.2010.-The respiratory distress syndrome (RDS) contributes to perinatal morbidity and mortality associated with preterm birth. Surfactant protein B (SP-B) is decreased in RDS. Both maternal antenatal steroid administration and chorioamnionitis reduce the incidence and severity of RDS. An important mediator in chorioamnionitis is IL-6 using the JAK-STAT signaling pathway for signal transduction. We hypothesized that the steroids, betamethasone (BTM) and dexamethasone (DXM), and IL-6 had synergistic effects on SP-B gene expression and STAT3 phosphorylation in H441 cells. DXM and BTM increased SP-B mRNA levels by 16.5 (13.3)-fold and IL-6 alone by 2.3-fold. After 48-h exposure of cells to DXM or BTM, IL-6 caused a significantly greater increase in SP-B mRNA levels (28.1-fold) than IL-6 or glucocorticoids alone. Whereas IL-6 stimulated tyrosine phosphorylation of STAT3 in a time-and dose-dependent way, DXM and BTM had no effect on STAT3 phosphorylation. Both DXM and BTM could potentiate IL-6-induced phosphorylation of STAT3. The synergism of glucocorticoids and IL-6 on SP-B gene expression and the effect of glucocorticoids on IL-6-induced STAT3 phosphorylation could be blocked by a JAK inhibitor. Expression level analysis showed that glucocorticoids increased the expression of the IL-6-binding alpha-subunit receptor (IL-6R) on mRNA and protein level. Our findings could represent an example of a pulmonary regulation system in which one role of glucocorticoids is to increase the effect of a cytokine by upregulation of its receptor. The described in vitro interaction of IL-6 and glucocorticoids could help explain the clinical observation that prenatal inflammation in preterm babies with antenatal steroid administration can attenuate severity of RDS.
Original languageEnglish
Pages (from-to)L578-L584
JournalAmerican Journal of Physiology-Lung Cellular and Molecular Physiology
Volume299
Issue number4
DOIs
Publication statusPublished - Oct 2010

Keywords

  • dexamethasone
  • betamethasone
  • surfactant protein B
  • interleukin-6 receptor
  • STAT3
  • Janus kinase
  • respiratory distress syndrome

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