Abstract: SA-PO716
A Novel IKKβ Inhibitor Ameliorates Podocyte and Kidney Injuries
Session Information
- Glomerular Diseases: Therapeutic Strategies
October 26, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Guo, Yiqing, Stony Brook University Renaissance School of Medicine, Stony Brook, New York, United States
- Gujarati, Nehaben A., Stony Brook University Renaissance School of Medicine, Stony Brook, New York, United States
- Chow, Andrew K., Stony Brook University Renaissance School of Medicine, Stony Brook, New York, United States
- Pabla, Navjot, The Ohio State University, Columbus, Ohio, United States
- Mallipattu, Sandeep K., Stony Brook University Renaissance School of Medicine, Stony Brook, New York, United States
Background
Previous studies showed that Krüppel-Like Factor 15 (KLF15) plays a protective role in the kidney through maintaining of podocyte differentiation. We developed a high-throughput screening (HTS) to identify KLF15 agonists as a therapy for proteinuric kidney diseases. Based on the structural activity relationship from the HTS, we designed and synthesized a novel compound, BT503 that was found to be protective in both in vitro and in vivo proteinuric models. Here, we demonstrate that BT503, directly inhibits IKKβ activity, resulting in loss of NFκB signaling.
Methods
IKKβ kinase activity was measured using either wild type IKKβ or gatekeeper mutant (M96V, in the ATP binding pocket) with BT503 as compared to vehicle. in vitro and in vivo profiling of BT503 was conducted using HPLC/MS/MS to characterize the drug properties. RNA-sequencing, in-silico drug-docking studies, and western blot analysis were also performed.
Results
Initial unbiased RNA-sequencing, in-silico drug-docking studies, and western blot analysis demonstrate that the salutary effects of BT503 in the podocyte are due to inhibition of IκBα phosphorylation, thereby preventing the nuclear translocation of p50/p65 and subsequent downregulation of KLF15. BT503 inhibits IKKβ kinase activity, which was abolished using an IKKβ gatekeeper mutant, suggesting that BT503 directly targets IKKβ. Thermal shift assay showed BT503 directly binds to IKKβ, but not IKKα and TAK1. BT503 also demonstrates low toxicity in cultured human podocytes and in mice. Expression of p50/65 was reduced in BT503-treated as compared to VEH-treated mice in proteinuric mouse models (HIV-1 transgenic mice, NTS-treated mice). Furthermore, knockout of KLF15 in podocytes attenuated the salutary effects of BT503, suggesting that the effects of IKKβ-p50/p65 are in part mediated by KLF15.
Conclusion
These data suggest that the salutary effects of a novel KLF15 agonist (BT503) are mediated through the direct inhibition of IKKβ kinase activity and subsequent canonical NFκB signaling.
Funding
- NIDDK Support