Discovery and Anti-inflammatory Activity of a Cyanobacterial Macrolide Glycoside Targeting the Keap1/Nrf2 Pathway

We discovered a cyanobacterial macrolide glycoside that contains an α,β-unsaturated carbonyl system a key motif required for the activation of the Keap1/Nrf2−ARE pathway that is involved in the activation of antioxidant and phase II detoxification enzymes. The compound was screened in ARE luciferase reporter gene assay which induced Nrf2 activity at 32 and 10µM. Given the established crosstalk between oxidative stress and inflammation, we aimed at investigating the antiinflammatory potential of our compound using RAW264.7 mouse macrophage. We carried RNAseq to capture the effects of the compound on transcript levels and identify additional pathways involved in inflammation that could be modulated. We further evaluated the cytotoxicity of the compound against HCT 116 and carried out RNAseq at the same cell line. RAW264.7 mouse macrophage cells were treated with two concentrations (32, 10 µM) of the macrolide glycoside in addition to solvent control (DMSO) for 1h followed by stimulation with Lipopolysaccharide (LPS). The RNA was collected after 12h. RNA from cells treated with DMSO without LPS stimulation were also obtained. For the HCT116, the same experimental design was carried out but without LPS stimulation.