MODULATING EFFECTS OF 5,5-DIMETHYL- 1-PYRROLINE N-OXIDE ON THE TRANSCRIPTOME OF LIPOPOLYSACCHARIDE-PRIMED MACROPHAGES

MARÍA CECILIA DELLAVEDOBA; SANDRA GOMEZ-MEJIBA ; DOUGLAS GANINI DA SILVA; RONALD MASON; MARCOS DAVID MUÑOZ ; SERGIO ALVAREZ ; DARIO C RAMIREZ

BS AS

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

SAIC, SAIB, SAI, SAFE, SAA, SAA, SAFIS,

The search for mechanism-based therapeutics against chronicinflammation (CI) is a highly desired focus of pharmaceutical industries.The switch of macrophages phenotype from a normal M2 towardsan inflammatory M1 phenotype is known to play an importantpathogenic role in a number of CI diseases, including adipose tissueinflammation in obesity. 5,5-dimethyl-1-pirroline N-oxide (DMPO) isa nitrone spin trap originally synthesized as a spin trap for studyof free radicals. Previously we found that DMPO can also produceanti-inflammatory effects in a mouse model of diet-induced obesity.However information regarding transcriptional effects of this spintrap remains unknown. Herein, we hypothesize that DMPO by itselfcan prevent LPS-induced M1-like activation of macrophagesby changing its transcriptome. To test this hypothesis we incubatedRAW 264.7 cells with 1 ng/ml LPS in the presence or absence of 50mM DMPO for 6h. RNA was extracted and used for transcriptomicsanalyses using microarray technology (Illumina). Functional dataanalysis showed 79 differentially expressed genes (DEGs) in DMPOvs Control comparison (ONE-way ANOVA with a FDR = 0.05). Weused DAVID databases for identifying enriched Gene onthologyterms and Ingenuity Pathway Analysis (IPA) for functional analysis.We found that DMPO DEGs were related to immune system processand negative regulation of innate immune response amongothers. Functional analysis indicated that IRF7 and TLRs were related(predicted inhibitions) to the observed transcriptomic effectsof DMPO. Functional data analyses were consistent with DMPOdampening LPS-induced inflammation in RAW 264.7, these effectswere confirmed using Nanostring technology. Taking together ourdata surprisingly indicates that DMPO by itself affects gene expressionrelated to regulation of immune system. This idea suggestsDMPO can serve as a structural platform for the design of novelcompounds to reduce macrophage activation at inflammation sites.Keywords: macrophage, lypopolysaccharide, phenotypic switch,DMPO, transcriptomics