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Abstract: SA-PO1164

Role of Nephrotoxic Serum-Driven Ferroptosis in Ncf1-p.R90H KI Female Mice

Session Information

  • CKD: Mechanisms - 3
    October 26, 2024 | Location: Exhibit Hall, Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2303 CKD (Non-Dialysis): Mechanisms

Authors

  • Stefanenko, Mariia, Medical University of South Carolina, Charleston, South Carolina, United States
  • Wang, Lei, Medical University of South Carolina, Charleston, South Carolina, United States
  • Fedoriuk, Mykhailo, Medical University of South Carolina, Charleston, South Carolina, United States
  • Cherezova, Alena, Augusta University, Augusta, Georgia, United States
  • Ilatovskaya, Daria, Augusta University, Augusta, Georgia, United States
  • Sung, Sun-sang J., University of Virginia, Charlottesville, Virginia, United States
  • Tsao, Betty, Medical University of South Carolina, Charleston, South Carolina, United States
  • Palygin, Oleg, Medical University of South Carolina, Charleston, South Carolina, United States
Background

Systemic Lupus Erythematosus (SLE) is an autoimmune disorder characterized by deposition of autoantibodies and immune complex formation, leading to inflammation and impaired organ function. The activation of NOX2, facilitated by efferocytosis, is disrupted by the substitution of arginine (R) for histidine (H) in the NCF1/p47phoxprotein, which reduces NOX2's ability to produce reactive oxygen species, exacerbating autoimmune responses and affecting redox balance in SLE pathogenesis in humans and mouse models on the C57BL/6 background. This study explores the mechanisms of ferroptosis in the renal proximal tubules (PT) of the H90.B6 knock in (KI) mice and examines potential sexual dimorphism in nephrotoxic serum (NTS)-driven tubulointerstitial disease.

Methods

The R90.B6 wild-type (WT) and H90.B6 KI female littermates were injected with either sheep (control) or NTS and kidneys were harvested after two weeks. Prussian blue histochemical staining was performed on fixed tissue to detect ferroptosis and PT damage. Freshly isolated PT was obtained by vibrodissociation, and ex vivo confocal imaging with fluorescent indicators was performed to assess ferrous ion (Fe2+) presence (Mito-FerroGreen) and mitochondrial membrane potential (ΔΨm, JC1) in PT cells, respectively.

Results

Histochemical staining revealed elevated ferroptosis in NTS-treated H90.B6 compared to the NTS-treated R90.B6 littermates (P<0.05) but not in control-treated groups. The confocal microscopy confirmed a high prevalence of mitochondrial ferrous ion in PT of female H90.B6 NTS- treated group that control-treated and NTS-treated WT and KI were 4±3, 2±1, 4±2, 17±4 % of PT ferroptosis (n≥74 tubule/ group, P<0.05). The accumulation of mitochondrial ferrous iron in PT was also confirmed by acute ammonium iron (II) sulfate applications. Compared to control serum treatment, the NTS-treated R90.B6 and H90.B6 groups showed a reduced ΔΨm.

Conclusion

The human SLE causal variant NCF1-H90 variant promotes ferroptosis in PT of non-autoimmune mice. These findings underscore the importance of understanding the role of redox mechanisms in linking ferroptosis, nitrosative stress, and lipid peroxidation in NCF1-p.R90H (H90) variant, highlighting the need to better understanding of tubulointerstitial disease in SLE.

Funding

  • NIDDK Support