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Cytokines Interleukin-1β and Tumor Necrosis Factor-α Regulate Different Transcriptional and Alternative Splicing Networks in Primary β-Cells

  1. Fernanda Ortis1,
  2. Najib Naamane1,
  3. Daisy Flamez1,
  4. Laurence Ladrière1,
  5. Fabrice Moore1,
  6. Daniel A. Cunha1,
  7. Maikel L. Colli1,
  8. Thomas Thykjaer2,
  9. Kasper Thorsen3,
  10. Torben F. Ørntoft2,3 and
  11. Decio L. Eizirik1
  1. 1Laboratory of Experimental Medicine, Université Libre de Bruxelles, Brussels, Belgium;
  2. 2CMO Aros Applied Biotechnology A/S, Science Park Skejby Brendstrupgaardsvej, Aarhus, Denmark;
  3. 3Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark.
  1. Corresponding author: Decio L. Eizirik, deizirik{at}ulb.ac.be.
  1. F.O. and N.N. contributed equally to this article.

Abstract

OBJECTIVE Cytokines contribute to pancreatic β-cell death in type 1 diabetes. This effect is mediated by complex gene networks that remain to be characterized. We presently utilized array analysis to define the global expression pattern of genes, including spliced variants, modified by the cytokines interleukin (IL)-1β + interferon (IFN)-γ and tumor necrosis factor (TNF)-α + IFN-γ in primary rat β-cells.

RESEARCH DESIGN AND METHODS Fluorescence-activated cell sorter–purified rat β-cells were exposed to IL-1β + IFN-γ or TNF-α + IFN-γ for 6 or 24 h, and global gene expression was analyzed by microarray. Key results were confirmed by RT-PCR, and small-interfering RNAs were used to investigate the mechanistic role of novel and relevant transcription factors identified by pathway analysis.

RESULTS Nearly 16,000 transcripts were detected as present in β-cells, with temporal differences in the number of genes modulated by IL-1β + IFNγ or TNF-α + IFN-γ. These cytokine combinations induced differential expression of inflammatory response genes, which is related to differential induction of IFN regulatory factor-7. Both treatments decreased the expression of genes involved in the maintenance of β-cell phenotype and growth/regeneration. Cytokines induced hypoxia-inducible factor-α, which in this context has a proapoptotic role. Cytokines also modified the expression of >20 genes involved in RNA splicing, and exon array analysis showed cytokine-induced changes in alternative splicing of >50% of the cytokine-modified genes.

CONCLUSIONS The present study doubles the number of known genes expressed in primary β-cells, modified or not by cytokines, and indicates the biological role for several novel cytokine-modified pathways in β-cells. It also shows that cytokines modify alternative splicing in β-cells, opening a new avenue of research for the field.

Footnotes

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • See accompanying commentary, p. 335.

    • Received August 5, 2009.
    • Accepted October 28, 2009.
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