Nrf2 overexpression protects against paraquat‑induced A549 cell injury primarily by upregulating P‑glycoprotein and reducing intracellular paraquat accumulation

Abstract

Paraquat (PQ) intoxication causes thousands of mortalities every year, worldwide. Its pulmonary-targeted accumulation and the acute lung injury it subsequently causes, remain a challenge for detoxification treatment. A previous study has demonstrated that the upregulation of nuclear factor erythroid-2 related factor 2 (Nrf2) prevents PQ toxicity in cell line and murine models. As Nrf2 target genes include a group of membrane transporters, the current study assessed the protective mechanism exerted by Nrf2 against PQ toxicity and intracellular PQ accumulation via its effects on P-glycoprotein (P-gp), a downstream transporter of Nrf2. Adenovirus vectors containing the Nrf2 gene were transfected into A549 cells. Cell proliferation was assessed by Cell Counting Kit-8. The levels of LDH, MDA, SOD, TNF-α, IL-6 levels were detected using their respective ELISA kits. In addition, the levels of Nrf2 and P-gp protein expression were detected by western blot analysis. The concentration of PQ was measured by HPLC. The results revealed that overexpressed Nrf2 significantly increased P-gp protein levels, decreased the intracellular accumulation of PQ and attenuated PQ-induced toxicity. However, the protective effects of Nrf2 overexpression on PQ-challenged A549 cells were abrogated following cyclosporine A treatment, a competitive inhibitor of P-gp, which also increased intracellular PQ levels. These data indicated that Nrf2 gene overexpression prevented PQ toxicity in A549 cells, potentially via the upregulation of P-gp activity and the inhibition of intracellular PQ accumulation. Thus, Nrf2 and P-gp may serve as potential therapeutic targets for the treatment of PQ-induced injury.

In vitro exosomal transfer of Nrf2 led to the oxaliplatin resistance in human colorectal cancer LS174T cells

“…These features confirm the critical role of Nrf2 in the control of resistance in cancer cells in response to chemotherapeutic agents. In line with our results, Payandeh et al 29,30 33 In another study, Exo harboring ubiquitin carboxy-terminal hydrolase-L1-mediated adriamycin resistance in breast cancer cells. 34 Concerning drug resistance in CC, several different proteins have been identified.…”

“…Similar to our results, Zhang et al 32 showed that exosomal transfer of p‐STAT3 confers 5‐fluorouracil resistance in colorectal cancer cells. It has been shown that Exo‐mediated transfer of chloride intracellular channel 1 increases vincristine resistance in gastric cancers 33 . In another study, Exo harboring ubiquitin carboxy‐terminal hydrolase‐L1‐mediated adriamycin resistance in breast cancer cells 34 …”

“…Some previous studies have shown P-gp expression is closely associated with the effectiveness of chemotherapy 11,[16][17][18] and that its expression is largely regulated by Nrf2. 33,35 To further elucidate the role of Nrf2 in the development of 1-OHP resistance, we evaluated the expression F I G U R E 6 Exosomal Nrf2 enhances P-gp expression in recipient cells. (A,B) Western blot analysis of HO-1, NQO1, and P-gp as the main Nrf2 downstream target genes in LS174T/S and Exo/R-treated LS174T/S cells.…”

Homology Modeling of the Human P-glycoprotein (ABCB1) and Insights into Ligand Binding through Molecular Docking Studies

“…These are essentially electrostatic interactions due to the negatively Regarding PQ and GEN compounds, even though the experimental transport assay results in Figure 11 show that these compounds at 50 µM do not interfere with the P-gp mediated efflux of R123 out of Caco-2 cells, the estimated binding energies have very favorable values. The literature available reveals different results regarding PQ and P-gp interaction (e.g., some authors stated that PQ is transported by P-gp [58] while others stated that it is not a P-gp substrate [59]). In the resulting binding pose (Figure 19), PQ forms hydrophobic interactions involving four residues in the binding pocket (Y310, F314, F728, and 732), all of them π-π type of interaction.…”

Ginkgolide C Alleviates Acute Lung Injury Caused by Paraquat Poisoning via Regulating the Nrf2 and NF-κB Signaling Pathways

“…Importantly, more recent researches have expounded that Nrf2 played an essential role in the regulation of oxidative stress and Nrf2 activation is a key event throughout the development of PQ poisoning [ 28 ]. Based on the in vivo and in vitro results, we also proved that Nrf2 was mainly in the cytoplasm of cells rather than in nucleus under unstressed conditions.…”