Skip Navigation LinksHome > October 2012 - Volume 40 - Issue 10 > Corticosteroid resistance in sepsis is influenced by microRN...
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Critical Care Medicine:
doi: 10.1097/CCM.0b013e31825b8ebc
Feature Articles

Corticosteroid resistance in sepsis is influenced by microRNA-124–induced downregulation of glucocorticoid receptor-α*

Ledderose, Carola VMD; Möhnle, Patrick MD; Limbeck, Elisabeth MSc; Schütz, Stefanie PhD; Weis, Florian MD; Rink, Jessica BSc; Briegel, Josef MD; Kreth, Simone MD, PhD

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Abstract

Objective: Acquired glucocorticoid resistance frequently complicates the therapy of sepsis. It leads to an exaggerated proinflammatory response and has been related to altered expression profiles of glucocorticoid receptor isoforms glucocorticoid receptor-α (mediating anti-inflammatory effects) and glucocorticoid receptor-β (acting as a dominant negative inhibitor). We investigated the impact of glucocorticoid receptor isoforms on glucocorticoid effects in human T-cells. We hypothesized that 1) changes of the ratio of glucocorticoid receptor isoforms impact glucocorticoid resistance and 2) glucocorticoid receptor-α expression is controlled by microRNA-mediated gene silencing.

Design: Laboratory-based study.

Setting: University research laboratory.

Subjects and Patients: Healthy volunteers, sepsis patients.

Methods: First, T-cells from healthy volunteers (native and CD3/CD28-stimulated cells with or without addition of hydrocortisone) were analyzed for the expression of glucocorticoid receptor-isoforms by quantitative polymerase chain reaction. Additionally, effects of gene silencing of glucocorticoid receptor-β by siRNA transfection were determined. Secondly, microRNA-mediated silencing was evaluated by cloning of a glucocorticoid receptor-α–specific 3′-untranslated-region reporter construct and subsequent transfection experiments in cell cultures. Effects of miRNA transfection on glucocorticoid receptor-α expression were analyzed in Jurkat T-cells and in T-cells from healthy volunteers (quantitative polymerase chain reaction and Western blotting). Finally, expression of glucocorticoid receptor-α, glucocorticoid receptor-β, and miR-124 was tested in T-cells of sepsis patients (n = 24).

Measurements and Main Results: Stimulation of T-cells induced a significant upregulation of glucocorticoid receptor-α (not glucocorticoid receptor-β) thereby possibly rendering T-cells more sensitive to glucocorticoids; this T-cell response was hindered by hydrocortisone. Silencing of glucocorticoid receptor-β doubled the inhibitory effects of glucocorticoids on interleukin-2 production. MicroRNA-124 was proved to specifically downregulate glucocorticoid receptor-α. Furthermore, a glucocorticoid-induced three-fold upregulation of microRNA-124 was found. T-cells of sepsis patients exhibited slightly decreased glucocorticoid receptor-α and slightly increased miR-124 expression levels, whereas glucocorticoid receptor-β expression was two-fold upregulated (p < .01) and exhibited a remarkable interindividual variability.

Conclusions: Glucocorticoid treatment induces expression of miR-124, which downregulates glucocorticoid receptor-α thereby limiting anti-inflammatory effects of glucocorticoids. Steroid treatment might aggravate glucocorticoid resistance in patients with high glucocorticoid receptor-β levels.

© 2012 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins

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