UDP-glycosyltransferase UGT96C10 functions as a novel detoxification factor for conjugating the activated dinitrotoluene sulfonate in switchgrass.

Dinitrotoluene sulfonates (DNTSes) are highly toxic hazards regulated by the Resource Conservation and Recovery Act (RCRA) in the United States. The trinitrotoluene (TNT) red water formed during the TNT purification process consists mainly of DNTSes. Certain plants, including switchgrass, reed and alfalfa, can detoxify low concentrations of DNTS in TNT red water-contaminated soils. However, the precise mechanism by which these plants detoxify DNTS remains unknown. In order to aid in the development of phytoremediation resources with high DNTS removal rates, we identified and characterized 1-hydroxymethyl-2,4-dinitrobenzene sulfonic acid (HMDNBS) and its glycosylated product HMDNBS O-glucoside as the degradation products of 2,4-DNT-3-SO3Na, the major isoform of DNTS in TNT red water-contaminated soils, in switchgrass via LC-MS/MS- and NMR-based metabolite analyses. Transcriptomic analysis revealed that 15 UDP-glycosyltransferase genes were dramatically upregulated in switchgrass plants following 2,4-DNT-3-SO3Na treatment. We expressed, purified and assayed the activity of recombinant UGT proteins in vitro and identified PvUGT96C10 as the enzyme responsible for the glycosylation of HMDNBS in switchgrass. Overexpression of PvUGT96C10 in switchgrass significantly alleviated 2,4-DNT-3-SO3Na-induced plant growth inhibition. Notably, PvUGT96C10-overexpressing transgenic switchgrass plants removed 83.1% of 2,4-DNT-3-SO3Na in liquid medium after 28 days, representing a 3.2-fold higher removal rate than that of control plants. This work clarifies the DNTS detoxification mechanism in plants for the first time, suggesting that PvUGT96C10 is crucial for DNTS degradation. Our results indicate that PvUGT96C10-overexpressing plants may hold great potential for the phytoremediation of TNT red water-contaminated soils.

Erigeron annuus Extract Improves DNCB-Induced Atopic Dermatitis in a Mouse Model via the Nrf2/HO-1 Pathway.

Atopic dermatitis (AD) is a persistent inflammatory skin condition resulting from an intricate interplay among genetic, immunological, and environmental factors. Erigeron annuus (EA), an annual winter plant belonging to the family Asteraceae, possesses anti-inflammatory, cytoprotective, and antioxidant activities. In this study, we hypothesized that Erigeron annuus extract (EAE) could be an effective agent for ameliorating AD-like symptoms. To confirm this hypothesis in vitro, we used H2O2-stimulated human keratinocytes (HaCaT cells) to demonstrate that pre-treatment with EAE protected against oxidative stress. HaCaT cells pretreated with EAE and stimulated with H2O2 showed decreased intracellular malondialdehyde content, increased superoxide dismutase activity, and reduced intracellular reactive oxygen species accumulation. To verify the in vivo hypothesis based on the intracellular results, an AD disease mouse model was induced with 1-chloro-2,4-dinitrobenzene (DNCB), and EAE was orally administered at a non-toxic concentration according to the toxicity evaluation results. The results showed that AD disease models in BALB/c mice exhibited reduced ear epidermal thickness, scratching behavior, and mast cell infiltration. In conclusion, our results indicate that EAE has the potential to improve AD by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway.