Comparative effectiveness of 4 natural and chemical activators of Nrf2 on inflammation, oxidative stress, macrophage polarization, and bactericidal activity in an in vitro macrophage infection model

PLoS One. 2020 Jun 8;15(6):e0234484. doi: 10.1371/journal.pone.0234484. eCollection 2020.

Abstract

Inflammation plays a crucial role in the defense response of the innate immune system against pathogen infection. In this study, we selected 4 compounds for their potential or proven anti-inflammatory and/or anti-microbial properties to test on our in vitro model of bacteria-infected THP-1-derived macrophages. We first compared the capacity of sulforaphane (SFN), wogonin (WG), oltipraz (OTZ), and dimethyl fumarate (DMF) to induce the nuclear factor erythroid 2-related factor 2 (Nrf2), a key regulator of the antioxidant, anti-inflammatory response pathways. Next, we performed a comparative evaluation of the antioxidant and anti-inflammatory efficacies of the 4 selected compounds. THP-1-derived macrophages and LPS-stimulated macrophages were treated with each compound and expression levels of genes coding for inflammatory cytokines IL-1β, IL-6, and TNF-α were quantified by RT-qPCR. Moreover, expression levels of genes coding for M1 (IL-23, CCR7, IL-1β, IL-6, and TNF-α) and M2 (PPARγ, MRC1, CCL22, and IL-10) markers were determined in classically-activated M1 macrophages treated with each compound. Finally, the effects of each compound on the intracellular bacterial survival of gram-negative E. coli and gram-positive S. aureus in THP-1-derived macrophages and PBMC-derived macrophages were examined. Our data confirmed the anti-inflammatory and antioxidant effects of SFN, WG, and DMF on LPS-stimulated THP-1-derived macrophages. In addition, SFN or WG treatment of classically-activated THP-1-derived macrophages reduced expression levels of M1 marker genes, while SFN or DMF treatment upregulated the M2 marker gene MRC1. This decrease in expression of M1 marker genes may be correlated with the decrease in intracellular S. aureus load in SFN- or DMF-treated macrophages. Interestingly, an increase in intracellular survival of E. coli in SFN-treated THP-1-derived macrophages that was not observed in PBMC-derived macrophages. Conversely, OTZ exhibited pro-oxidant and proinflammatory properties, and affected intracellular survival of E. coli in THP-1-derived macrophages. Altogether, we provide new potential therapeutic alternatives in treating inflammation and bacterial infection.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents / pharmacology*
  • Antioxidants / pharmacology*
  • Dimethyl Fumarate / pharmacology
  • Escherichia coli / drug effects
  • Escherichia coli Infections / drug therapy*
  • Escherichia coli Infections / immunology
  • Flavanones / pharmacology
  • Humans
  • Inflammation / drug therapy*
  • Inflammation / immunology
  • Isothiocyanates / pharmacology
  • Leukocytes, Mononuclear
  • Macrophage Activation / drug effects*
  • Macrophage Activation / immunology
  • Macrophages / cytology
  • Macrophages / drug effects
  • Macrophages / immunology
  • NF-E2-Related Factor 2 / immunology*
  • Oxidative Stress / drug effects*
  • Oxidative Stress / immunology
  • Pyrazines / pharmacology
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / immunology
  • Staphylococcus aureus / drug effects
  • Sulfoxides
  • THP-1 Cells
  • Thiones
  • Thiophenes

Substances

  • Anti-Inflammatory Agents
  • Antioxidants
  • Flavanones
  • Isothiocyanates
  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • Pyrazines
  • Sulfoxides
  • Thiones
  • Thiophenes
  • oltipraz
  • Dimethyl Fumarate
  • sulforaphane
  • wogonin

Grants and funding

This work was supported by funding from the Chancellerie des Universités de Paris Legs Poix (MB, SV), the Institut national de la santé et de la recherche médicale INSERM (TBD, MB), and the UVSQ (TBD, MB, SV). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.