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Kidney Week

Abstract: PO0601

Inhibition of KIM-1-Mediated Fatty Acid Uptake by a Novel Inhibitor Attenuates Pro-Fibrotic Responses in Multiple Models of Human Primary Kidney Epithelial Cells Including Kidney Tubuloids

Session Information

  • CKD Mechanisms - 1
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2103 CKD (Non-Dialysis): Mechanisms

Authors

  • Mori, Yutaro, Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Ajay, Amrendra Kumar, Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Patel, Ankit B., Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Siedlecki, Andrew M., Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Kishi, Seiji, Department of Nephrology, Tokushima University Hospital, Tokushima, Tokushima, Japan
  • Ichimura, Takaharu, Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Bonventre, Joseph V., Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
Background

Tubulointerstitial damage is strongly associated with many forms of kidney injury including diabetic kidney disease. Kidney Injury Molecule-1 (KIM-1), a scavenger receptor, is the most upregulated proximal tubule protein with kidney injury. We hypothesized that KIM-1-mediated uptake of fatty acids (FAs) contributes to tubulointerstitial damage.

Methods

Human DKD renal biopsy samples were analyzed. Human primary epithelial cell cultures were established from the non-tumor kidney tissue removed from patients with a renal mass. To grow human renal tubuloids, primary cells were cultured on ultra-low attachment plates for several days. Cells were transferred into media containing multiple growth factors and 5% fetal bovine serum. Cells and tubuloids were treated with palmitate acid with certain groups having siRNA knockdown of KIM-1. Conditioned media from FA-treated human primary cells and tubuloids were applied to mouse primary kidney fibroblasts. An inhibitor for KIM-1-mediated FA-uptake was identified from >14,400 compounds and tested for its anti-fibrotic ability.

Results

KIM-1 expression in DKD patients was positively correlated with tubulointerstitial inflammation and fibrosis. FA-BSA uptake was markedly reduced in cells depleted of KIM-1 indicating the relative importance of KIM-1 to proximal tubule FA uptake. High-dose FA treatment increased cell death. FA treatment increasedγH2AX expression, a marker for DNA damage response. FA also increased the number of cells in the G2/M phase without an increase of those in S phase by cell cycle analysis, indicating that cells are likely arrested in G2/M phase. Our newly identified inhibitor for KIM-1, JB1, prevented FA uptake at least in part by inhibiting the direct binding of FA to KIM-1. JB1 reduced the pro-fibrotic effect of conditioned media from FA-treated human primary cells and tubuloids.

Conclusion

KIM-1 enhances the proximal tubular uptake of FA, leading to proximal tubule damage, pro-fibrotic responses and increase in cell death. Our findings support the role of KIM-1 as a target for chronic kidney disease including DKD and our work introduces a new candidate therapeutic agent.

Funding

  • NIDDK Support