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Abstract: FR-PO089

The Protective Role of Nrf2 Against Aristolochic Acid (AA)-Induced Renal Tubular Epithelial Cell Injury

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Huang, Xuan, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
  • Wu, Juan, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
  • Wu, Haishan, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
  • Liu, Xinhui, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
  • Yu, Xueqing, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
  • Yang, Xiao, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
Background

Aristolochic acid nephropathy(AAN) is a rapidly progressive tubulointerstitial disease induced by aristolochic acid(AA) and there are currently no effective treatments for it. Nrf2, as a major regulator of antioxidant response, has been proven by numerous studies to be protective in acute kidney injury and chronic kidney disease progression. However, its role in AA-induced kidney injury has not been elucidated yet. We previously demonstrated that Bardoxolone methyl(BARD) ameliorates AA-induced acute kidney injury through Nrf2 pathway. In this study, we further assessed the role of Nrf2 in AA-induced renal tubular epithelial cell injury.

Methods

NRK-52E cells were incubated with different concentrations of AA for 0-24 hours to evaluate cell viability, Nrf2 signaling pathway protein levels, ROS production, and cell apoptosis/necrosis. The role of Nrf2 in AA-induced ROS production and cell apoptosis/necrosis was determined through Nrf2 knockdown by its specific siRNA or Nrf2 overexpression by Nrf2 plasmid, respectively. Cell viability was evaluated by MTT. Cells were labeled with DCFH-DA for detection of ROS by flow cytometry. The cells also doubly labeled with Annexin V and propidium iodide(PI) for measurement of cell apoptosis/necrosis by flow cytometry. Expression of Nrf2 and its downstream protein HO-1 and NQO1 was analyzed by western blotting.

Results

AA increased intracellular ROS production and cell apoptosis/necrosis in a time-dependent manner. Meanwhile, the cell viability and the expression of Nrf2 signaling pathway proteins (Nrf2, HO-1, NQO1) were significantly decreased. Downregulation of Nrf2 by its specific siRNA further increased ROS levels(25.2±12.5 vs 8.5±2.5, P<0.05) and cell apoptosis/necrosis(50.21±5.65% vs 35.81±0.97%, P<0.05), and reduced the expression of Nrf2 signaling pathway proteins(P<0.05). Conversely, overexpression of Nrf2 significantly decreased AA-induced ROS production and cell apoptosis/necrosis(24.12±1.61% vs 32.61±0.81%, P<0.01). The expression of Nrf2 and its downstream protein HO-1 were significantly upregulated compared with non-Nrf2 transfected group(P<0.05).

Conclusion

Impaired Nrf2 signaling pathway is one of the mechanisms of AA-induced renal tubular epithelial cell injury, and activation of Nrf2 can ameliorate the cell injury by its antioxidant effect.

Funding

  • Government Support - Non-U.S.