Regulation of the NRF2 transcription factor by andrographolide and organic extracts from plant endophytes
Fig 6
Effects of organic extracts isolated from the endophytes on NRF2.
(A) To screen the 49 organic extracts isolated from the endophytes for NRF2 transcriptional activation, the ARE reporter assay was performed as described under Materials and Methods. HEK293T cells were transfected with ARE-pGL2 plasmid for 24 hours before treatment with the organic extracts (0.5%) or sulforaphane (SF; 10 μM) for six hours before analysis. (B) Dose response of the effect of organic extracts on NRF2 transcriptional activation. The assay was carried out as in (A). (C) Morphology, Lacto-phenol Cotton Blue staining and identity (based on ≥99% sequence similarity of BLAST results) of the fungal endophyte from which ORX 41 was derived. (D) Western blot analysis of the effect of organic extract ORX 41 on the NRF2 protein concentration. HEK293T cells were transfected with HA-NRF2 for 2 days before treatment with vehicle (methanol treatment) or ORX 41 for 6 hours at the indicated concentrations, followed by Western blotting with HA and β-actin antibody.