Abstract: TH-OR136

A Small Molecule Inhibitor of ASK1 Modulates Biomarkers and Pathways Associated with Diabetic Kidney Disease (DKD)

Session Information

Category: Diabetes

  • 501 Diabetes Mellitus and Obesity: Basic - Experimental

Authors

  • Badal, Shawn S., Gilead Sciences, Foster City, California, United States
  • Yang, Haichun, Vanderbilt University , Nashville, Tennessee, United States
  • Li, Li, Gilead Sciences, Foster City, California, United States
  • Liu, Henry, Gilead Sciences, Foster City, California, United States
  • Fogo, Agnes B., Vanderbilt University , Nashville, Tennessee, United States
  • Breckenridge, David G., Gilead Sciences, Foster City, California, United States
  • Liles, John T., Gilead Sciences, Foster City, California, United States
Background

Apoptosis signal-regulating kinase 1 (ASK1) promotes inflammation, apoptosis, and fibrosis via activation of MAPK kinases p38 and c-Jun N terminal kinase (JNK). ASK1 pathway activation has been demonstrated in human DKD biopsies and in kidneys of db/db eNOS-/- mice. Clinically relevant urinary biomarkers associated with kidney damage and GFR decline in DKD patients have not been investigated in this animal model. This study evaluated effects of a selective, small molecule ASK1 inhibitor on urinary biomarkers and expression of DKD-related genes in db/db eNOS-/- mice.

Methods

db/db eNOS-/- mice were treated with a structural analog of the ASK1 inhibitor, Selonsertib, (GS-444217, 0.3% in chow) or vehicle for 8 weeks, starting at 10 weeks of age (baseline) (n=8-10 mice/group). At 18 weeks of age EGF, KIM-1 and TIMP1 levels in urine were quantified at end of study by ELISA and values normalized to urine creatinine levels. GFR was measured by FITC-inulin clearance. Kidney cortex mRNA was isolated and gene expression analyzed by qPCR and RNA-Seq.

Results

At 18 weeks, vehicle-treated mice had significant reductions in GFR (212± 21 vs 296±27 ml/min, p=0.0265) and uEGF levels (1.38 ± 0.11 vs 2.17± 0.27 μg/mg, p=0.0067) compared to baseline. ASK1 inhibition halted GFR decline (365± 31 vs 212± 21 ml/min, p=0.0007), prevented decreases in uEGF (2.51± 0.23 μg/mg vs 1.38±0.11, p=0.0003) and preserved kidney Egf mRNA levels. ASK1 inhibition reduced urinary TIMP1 (481.5± 96.3 vs 903.4± 158.8 pg/mg, p=0.0473) and Timp1 mRNA, compared to vehicle. Additionally, urinary KIM-1 as well as Havcr1 (KIM-1), Lcn2 (NGAL), Mcp1, and Tnf mRNA were all significantly reduced by ASK1 inhibition. Gene set enrichment analysis (GSEA) of RNA-Seq data revealed that TNFα signaling and inflammatory response pathways were enriched in db/db eNOS-/- mice and down-regulated by treatment with an ASK1 inhibitor.

Conclusion

Biomarkers related to kidney injury, inflammation, fibrosis and GFR decline in DKD patients are dysregulated in db/db eNOS-/- mice. The administration of an ASK1 inhibitor improved these biomarker levels and kidney function. These data establish db/db eNOS-/- mice as a relevant model to evaluate drug effects on biomarkers associated with GFR decline.

Funding

  • Commercial Support