Kidney Week

Abstract: FR-PO1025

Exaggerated Angiotensin II-Induced NF-kB p65 Signaling and Oxidative Stress in GSTM1-Deficient Kidney Primary Tubular Epithelial Cells Is Ameliorated by Hydrogen Sulfide

Session Information

• CKD Mechanisms: From Mendel to Mars
  November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2303 CKD (Non-Dialysis): Mechanisms

Authors

• Chen, Luojing, University of Rochester Medical Center, Rochester, New York, United States

Luojing Chen,

• Beane, Timothy Jason, University of Rochester Medical Center, Rochester, New York, United States

Timothy Jason Beane,

• Wang, Yves T., University of Rochester Medical Center, Rochester, New York, United States

Yves T. Wang,

• Alnuaimi, Ahmed Q., University of Rochester Medical Center, Rochester, New York, United States

Ahmed Q. Alnuaimi,

• Le, Thu H., University of Rochester Medical Center, Rochester, New York, United States

Thu H. Le,

Background

Glutathione S-transferase μ-1 (GSTM1) belongs to the superfamily of GSTs that are phase II antioxidant enzymes regulated by nuclear factor erythroid 2-related factor 2 (Nrf2). In humans, homozygous carriers of the common GSTM1(0) null allele are deficient of the enzyme and have increased risks of chronic kidney disease (CKD) progression. Global Gstm1 knockout (KO) mice have increased renal levels of reactive oxygen species (ROS), inflammation, and kidney injury in angiotensin II (Ang II)-induced hypertension. We previously reported that deletion of Gstm1 augments Ang II activation of proinflammatory NF-kB p65 signaling pathway in primary tubular epithelial cells (PTECs). Recently, we discovered that GSTM1 modulates the transsulfuration (TSP)-hydrogen sulfide (H₂S) pathway; loss of GSTM1 downregulates H₂S production. GYY4137, an H₂S donor, has been shown to prevent multi-organ damage in disease models. We hypothesize that GYY4137 would ameliorate AngII-induced NF-kB activation and ROS production in Gstm1 KO PTECs.

Methods

PTECs were isolated from Gstm1 KO and wild-type (WT) kidneys. Cells were starved for 4 hr, then treated with Ang II (100 nM) and with or without GYY4137 (100 mM) for 24 hr. Cells were stained with anti-NF-kB p65 antibody and assayed for ROS production using ab113851 kit (Abcam). NF-kB p65 nuclear staining was quantified as % of p65 nuclei-positively stained cells to the total cells, with 5 random fields counted (n = 6 mice in each group).

Results

After Ang II treatment, compared to WT, KO PTECs had significantly increased nuclear p65 staining (% p65+ cells: WT 9.8 ± 1, KO 23.8. ± 2.5; p = 0.001), and ROS (1.48 x higher than WT; p = 0.002). Compared to Ang II only, Ang II + GYY4137 significantly decreased p65 nuclear translocation by 4.2% in WT (p = 0.02) and 11.4 % in KO (p=0.003), and ROS generation in both WT(55%, p = 0.002) and KO PTEC (68%, p = 0.001).

Conclusion

Deletion of Gstm1 augments Ang II induced ROS production and activation of NF-kB in PTECs in an H₂S dependent manner. Targeting the TSP-H2S pathway may be a novel therapeutic approach for CKD in those genetically susceptible.

Funding

• NIDDK Support