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Abstract: PO0927

Selonsertib Reduces TNFα-Induced Markers of Injury and Inflammation in an Organ-on-a-Chip Model of Proximal Tubular Injury

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Badal, Shawn S., Gilead Sciences Inc, Foster City, California, United States
  • Velasquez, Maile, Gilead Sciences Inc, Foster City, California, United States
  • Liles, John T., Gilead Sciences Inc, Foster City, California, United States
Background

Increased Circulating levels of TNF Superfamily Receptors 1 and 2 (TNFRSF1A and TNFRSF1B) in patients are associated with rapid declines in eGFR and proposed as biomarkers of DKD progression. In a phase 2 DKD trial which evaluated safety and efficacy of the ASK1 inhibitor Selonsertib (SEL), higher serum sTNFR1 levels associated with progression to End Stage Renal Disease (ESRD). In vitro, mono-culture studies have demonstrated that ASK1 signaling is required for TNFα induced apoptosis in kidney and other organ systems. Current studies with a microfluidic organ-on-a-chip system to investigate the effects of TNFα in a kidney co-culture system and determine effect of SEL treatment on kidney proximal tubular injury.

Methods

After populating cells in a co-culture, microfluidic device (Emulate Bio) containing either Lonza RPTEC (top channel) or kidney microvascular endothelial cells (bottom channel), TNFa (2ng/ml) was added at Day 0 along with SEL (10µM) to inlet flow of each channel. After 7 days, RNA was isolated from each channel and gene expression analyzed by qPCR. Outlet supernatant from each channel was analyzed for kidney injury and inflammation markers on Mesoscale Discovery device (MSD). Data shown as fold-of-change or mean ± standard error of the mean (s.e.m.)

Results

TNFα significantly increased expression of both TNFRSF1A and1B in the RPTEC channel (1.4 and 2.6-fold, respectively vs. control), and SEL decreased TNFRSF1A expression by 108% (p=0.0058) and lowered TNFRSF1B expression by 64% (p=0.1549). SEL decreased TNFα-induced expression of IP-10 (6.4 vs. 37.3-fold, p=0.0083) and IL-18 expression (0.67-fold vs 1.6-fold, p<0.0001) in proximal tubules. Osteoactivin and Clusterin, biomarkers used to assess proximal tubule injury were significantly increased in RPTEC supernatant following TNFα stimulation channel (2.1 and 3.7-fold, respectively, p<0.0001 for each). SEL significantly reduced levels of osteoactivin (139.6 ± 33.74 vs 778.2 ± 44.24 pg/ml, p<0.0001) and clusterin (28.9 ± 1.8 vs. 108.5 ± 1.7 ng/ml, p<0.0001).

Conclusion

In a microfluidic, RPTEC/Endothelial co-culture model, treatment with the ASK1 inhibitor Selonsertib reduced several markers of kidney injury. Efficacy to reduce inflammatory gene expression and biomarkers of proximal tubular damage indicate SEL treatment may have potential to impact DKD progression.

Funding

  • Commercial Support