The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide dampens lipopolysaccharide-induced transcriptomic changes in macrophages
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M1-like inflammatory phenotype of macrophages plays a critical role in tissue damage in chronic inflammatory diseases. Previously, we found that the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) dampens lipopolysaccharide (LPS)-triggered inflammatory priming of RAW 264.7 cells. Herein, we tested whether DMPO by itself can induce changes in macrophage transcriptome, and that these effects may prevent LPS-induced activation of macrophages.
Materials and methods
To test our hypothesis, we performed a transcriptomic and bioinformatics analysis in RAW 264.7 cells incubated with or without LPS, in the presence or in the absence of DMPO.
Functional data analysis showed 79 differentially expressed genes (DEGs) when comparing DMPO vs Control. We used DAVID databases for identifying enriched gene ontology terms and Ingenuity Pathway Analysis for functional analysis. Our data showed that DMPO vs Control comparison of DEGs is related to downregulation immune-system processes among others. Functional analysis indicated that interferon-response factor 7 and toll-like receptor were related (predicted inhibitions) to the observed transcriptomic effects of DMPO. Functional data analyses of the DMPO + LPS vs LPS DEGs were consistent with DMPO-dampening LPS-induced inflammatory transcriptomic profile in RAW 264.7. These changes were confirmed using Nanostring technology.
Taking together our data, surprisingly, indicate that DMPO by itself affects gene expression related to regulation of immune system and that DMPO dampens LPS-triggered MyD88- and TRIF-dependent signaling pathways. Our research provides critical data for further studies on the possible use of DMPO as a structural platform for the design of novel mechanism-based anti-inflammatory drugs.
KeywordsMacrophage Lipopolysaccharide Inflammation Transcriptomics DMPO
Authors want to express their gratitude to Dr Bart Frank (OMRF) for early processing of raw microarray data used in this study and to Dr Paula Di Sciullo for excellent technical assistance. This study was supported in part by the following agencies: PICT-3369 (FONCyT, AGENCIA, Argentina), PIP 916 (CONICET) and PROICO 2332 and PROICO 100414 (National University of San Luis). In addition, this research was also supported in part by the National Institute of Environmental Health Sciences.
Compliance with ethical standards
Conflict of interest
Authors declare no competing conflict of interest.
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