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Induction of acute phase response genes in keratinocytes following exposure to oligodeoxynucleotides
Alireza Mirmohammadsadegh1, Jan Maschke, Etiena Basner-Tschakarjan
1Department of Dermatology, Venerology and Allergology, University of Essen, Hufelandstrasse 55, 45122 Essen, Essen, Germany.
Abstract:
Keratinocytes have the ability to take up oligodeoxynucleotides (ODN) and plasmid DNA probably by receptor-mediated endocytosis. Despite the use of DNA for antisense and gene therapy little is known about the regulation of genes following exposure to nucleic acids. To systematically identify gene regulation in keratinocytes upon exposure to ODN we screened human cytokine DNA arrays containing 383 different genes and found interleukin (IL) 1alpha, IL-1beta, integrin-beta(1), alpha-tubulin, and follistatin highly induced, while most genes were unaffected. The time course and concentration dependence for IL-1alpha and follistatin expression were analyzed by standard northern blot technique. ODN of different length and sequence induced comparable amounts of IL-1alpha and follistatin. Their induction was independent of negative charge and of several proinflammatory compounds such as lipopolysaccharides, IL-1beta, and interferon-gamma but was partly inhibited by activin A. In summary, our study revealed several genes of the acute phase protein family that are induced in a non-sequence-specific manner following the exposure of normal human keratinocytes to ODN. Therefore it is tempting to speculate that upon internalization ODN bind to an intracellular receptor (e.g., Toll-like receptor 9) which mediates signaling.
Insights
Oligodeoxynucleotides (ODN) exposure induces specific genes like interleukin-1 alpha in human keratinocytes. This non-sequence-specific gene induction suggests ODN may interact with intracellular receptors, impacting gene regulation.
Area of Science:
- Cell Biology
- Molecular Biology
- Immunology
Background:
- Keratinocytes internalize DNA, but gene regulation by nucleic acids is poorly understood.
- Oligodeoxynucleotides (ODN) and plasmid DNA uptake occurs, likely via receptor-mediated endocytosis.
- Applications in antisense and gene therapy highlight the need to study DNA's effects on gene expression.
Purpose of the Study:
- To systematically identify genes regulated in keratinocytes upon exposure to ODN.
- To investigate the mechanism of gene induction by ODN in human skin cells.
- To explore potential intracellular pathways involved in ODN-mediated gene expression changes.
Main Methods:
- Screening of human cytokine DNA arrays with 383 genes to identify differentially expressed genes.
- Northern blot analysis to determine the time course and concentration dependence of specific gene induction.
- Testing the effect of ODN length, sequence, charge, and co-exposure to inflammatory compounds on gene expression.
Main Results:
- Interleukin (IL)-1alpha, IL-1beta, integrin-beta(1), alpha-tubulin, and follistatin were significantly induced by ODN.
- IL-1alpha and follistatin expression showed time and concentration-dependent induction.
- Induction was sequence-independent, unaffected by negative charge or inflammatory stimuli, but partially inhibited by activin A.
Conclusions:
- ODN exposure induces specific genes, including acute phase proteins, in human keratinocytes in a non-sequence-specific manner.
- The findings suggest ODN may bind to intracellular receptors, such as Toll-like receptor 9, initiating signaling pathways.
- This research provides insights into the cellular response to exogenous nucleic acids and potential therapeutic targets.