Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes

<p>Abstract</p> <p>Background</p> <p>Gene expression in lipopolysaccharide (LPS)-stimulated monocytes is mainly studied by quantitative real-time reverse transcription PCR (RT-qPCR) using GAPDH (glyceraldehyde 3-phosphate dehydrogenase) or ACTB (beta-actin) as reference...

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Main Authors: Øvstebø Reidun, Grimholt Runa M, Piehler Armin P, Berg Jens P
Format: Article
Language:English
Published: BMC 2010-05-01
Series:BMC Immunology
Online Access:http://www.biomedcentral.com/1471-2172/11/21
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author Øvstebø Reidun
Grimholt Runa M
Piehler Armin P
Berg Jens P
author_facet Øvstebø Reidun
Grimholt Runa M
Piehler Armin P
Berg Jens P
author_sort Øvstebø Reidun
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Gene expression in lipopolysaccharide (LPS)-stimulated monocytes is mainly studied by quantitative real-time reverse transcription PCR (RT-qPCR) using GAPDH (glyceraldehyde 3-phosphate dehydrogenase) or ACTB (beta-actin) as reference gene for normalization. Expression of traditional reference genes has been shown to vary substantially under certain conditions leading to invalid results. To investigate whether traditional reference genes are stably expressed in LPS-stimulated monocytes or if RT-qPCR results are dependent on the choice of reference genes, we have assessed and evaluated gene expression stability of twelve candidate reference genes in this model system.</p> <p>Results</p> <p>Twelve candidate reference genes were quantified by RT-qPCR in LPS-stimulated, human monocytes and evaluated using the programs geNorm, Normfinder and BestKeeper. geNorm ranked PPIB (cyclophilin B), B2M (beta-2-microglobulin) and PPIA (cyclophilin A) as the best combination for gene expression normalization in LPS-stimulated monocytes. Normfinder suggested TBP (TATA-box binding protein) and B2M as the best combination. Compared to these combinations, normalization using GAPDH alone resulted in significantly higher changes of TNF-α (tumor necrosis factor-alpha) and IL10 (interleukin 10) expression. Moreover, a significant difference in TNF-α expression between monocytes stimulated with equimolar concentrations of LPS from N. meningitides and E. coli, respectively, was identified when using the suggested combinations of reference genes for normalization, but stayed unrecognized when employing a single reference gene, ACTB or GAPDH.</p> <p>Conclusions</p> <p>Gene expression levels in LPS-stimulated monocytes based on RT-qPCR results differ significantly when normalized to a single gene or a combination of stably expressed reference genes. Proper evaluation of reference gene stabiliy is therefore mandatory before reporting RT-qPCR results in LPS-stimulated monocytes.</p>
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spelling doaj.art-42b3edb4b2d44bb1aadf58f87712c93c2022-12-22T00:58:03ZengBMCBMC Immunology1471-21722010-05-011112110.1186/1471-2172-11-21Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genesØvstebø ReidunGrimholt Runa MPiehler Armin PBerg Jens P<p>Abstract</p> <p>Background</p> <p>Gene expression in lipopolysaccharide (LPS)-stimulated monocytes is mainly studied by quantitative real-time reverse transcription PCR (RT-qPCR) using GAPDH (glyceraldehyde 3-phosphate dehydrogenase) or ACTB (beta-actin) as reference gene for normalization. Expression of traditional reference genes has been shown to vary substantially under certain conditions leading to invalid results. To investigate whether traditional reference genes are stably expressed in LPS-stimulated monocytes or if RT-qPCR results are dependent on the choice of reference genes, we have assessed and evaluated gene expression stability of twelve candidate reference genes in this model system.</p> <p>Results</p> <p>Twelve candidate reference genes were quantified by RT-qPCR in LPS-stimulated, human monocytes and evaluated using the programs geNorm, Normfinder and BestKeeper. geNorm ranked PPIB (cyclophilin B), B2M (beta-2-microglobulin) and PPIA (cyclophilin A) as the best combination for gene expression normalization in LPS-stimulated monocytes. Normfinder suggested TBP (TATA-box binding protein) and B2M as the best combination. Compared to these combinations, normalization using GAPDH alone resulted in significantly higher changes of TNF-α (tumor necrosis factor-alpha) and IL10 (interleukin 10) expression. Moreover, a significant difference in TNF-α expression between monocytes stimulated with equimolar concentrations of LPS from N. meningitides and E. coli, respectively, was identified when using the suggested combinations of reference genes for normalization, but stayed unrecognized when employing a single reference gene, ACTB or GAPDH.</p> <p>Conclusions</p> <p>Gene expression levels in LPS-stimulated monocytes based on RT-qPCR results differ significantly when normalized to a single gene or a combination of stably expressed reference genes. Proper evaluation of reference gene stabiliy is therefore mandatory before reporting RT-qPCR results in LPS-stimulated monocytes.</p>http://www.biomedcentral.com/1471-2172/11/21
spellingShingle Øvstebø Reidun
Grimholt Runa M
Piehler Armin P
Berg Jens P
Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes
BMC Immunology
title Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes
title_full Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes
title_fullStr Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes
title_full_unstemmed Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes
title_short Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes
title_sort gene expression results in lipopolysaccharide stimulated monocytes depend significantly on the choice of reference genes
url http://www.biomedcentral.com/1471-2172/11/21
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