Violacein Treatment Modulates Acute and Chronic Inflammation through the Suppression of Cytokine Production and Induction of Regulatory T Cells
Inflammation is a necessary process to control infection. However, exacerbated inflammation, acute or chronic, promotes deleterious effects in the organism. Violacein (viola), a quorum sensing metabolite from the Gram-negative bacterium Chromobacterium violaceum, has been shown to protect mice from...
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Published in | PloS one Vol. 10; no. 5; p. e0125409 |
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Main Authors | , , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Public Library of Science
04.05.2015
Public Library of Science (PLoS) |
Subjects | |
Online Access | Get full text |
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Summary: | Inflammation is a necessary process to control infection. However, exacerbated inflammation, acute or chronic, promotes deleterious effects in the organism. Violacein (viola), a quorum sensing metabolite from the Gram-negative bacterium Chromobacterium violaceum, has been shown to protect mice from malaria and to have beneficial effects on tumors. However, it is not known whether this drug possesses anti-inflammatory activity. In this study, we investigated whether viola administration is able to reduce acute and chronic autoimmune inflammation. For that purpose, C57BL/6 mice were intraperitoneally injected with 1 μg of LPS and were treated with viola (3.5mg/kg) via i.p. at the same time-point. Three hours later, the levels of inflammatory cytokines in the sera and phenotypical characterization of leukocytes were determined. Mice treated with viola presented a significant reduction in the production of inflammatory cytokines compared with untreated mice. Interestingly, although viola is a compound derived from bacteria, it did not induce inflammation upon administration to naïve mice. To test whether viola would protect mice from an autoimmune inflammation, Experimental Autoimmune Encephalomyelitis (EAE)-inflicted mice were given viola i.p. at disease onset, at the 10th day from immunization. Viola-treated mice developed mild EAE disease in contrast with placebo-treated mice. The frequencies of dendritic cells and macrophages were unaltered in EAE mice treated with viola. However, the sole administration of viola augmented the levels of splenic regulatory T cells (CD4+Foxp3+). We also found that adoptive transfer of viola-elicited regulatory T cells significantly reduced EAE. Our study shows, for the first time, that violacein is able to modulate acute and chronic inflammation. Amelioration relied in suppression of cytokine production (in acute inflammation) and stimulation of regulatory T cells (in chronic inflammation). New studies must be conducted in order to assess the possible use of viola in therapeutic approaches in human autoimmune diseases. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Competing Interests: The authors have declared that no competing interests exist. Conceived and designed the experiments: RT LV. Performed the experiments: RT SCPL ICNP FZ LKI ACC APB TAC RdG GFN. Analyzed the data: RT ND FTMC LV ALRO DRSM MACH. Contributed reagents/materials/analysis tools: DRSM ALRO MACH LV. Wrote the paper: RT SCPL ND FTMC LV. |
ISSN: | 1932-6203 1932-6203 |
DOI: | 10.1371/journal.pone.0125409 |