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Abstract: FR-PO343

Discovery of a Novel Autophagy Activator to Treat Autosomal Dominant Tubulointerstitial Kidney Disease

Session Information

Category: Genetic Diseases of the Kidneys

  • 1102 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Kim, Yeawon, Washington University in St Louis, St Louis, Missouri, United States
  • Li, Chuang, Washington University in St Louis, St Louis, Missouri, United States
  • Gu, Chenjian, Washington University in St Louis, St Louis, Missouri, United States
  • Tycksen, Eric, Washington University in St Louis, St Louis, Missouri, United States
  • Park, Sun-Ji, Washington University in St Louis, St Louis, Missouri, United States
  • Puri, Anuradhika, Washington University in St Louis, St Louis, Missouri, United States
  • Pietka, Terri A., Washington University in St Louis, St Louis, Missouri, United States
  • Sivapackiam, Jothilingam, Washington University in St Louis, St Louis, Missouri, United States
  • Kidd, Kendrah O., Wake Forest University, Winston-Salem, North Carolina, United States
  • Johnson, Bryce G., Pfizer Inc, New York, New York, United States
  • Kmoch, Stanislav, Univerzita Karlova, Prague, Czechia
  • Duffield, Jeremy Stuart, Prime Medicine, Cambridge, Massachusetts, United States
  • Bleyer, Anthony J., Wake Forest University, Winston-Salem, North Carolina, United States
  • Jackrel, Meredith, Washington University in St Louis, St Louis, Missouri, United States
  • Urano, Fumihiko, Washington University in St Louis, St Louis, Missouri, United States
  • Sharma, Vijay, Washington University in St Louis, St Louis, Missouri, United States
  • Lindahl, Maria, Helsingin yliopisto, Helsinki, Uusimaa, Finland
  • Chen, Ying Maggie, Washington University in St Louis, St Louis, Missouri, United States
Background

Autosomal dominant tubulointerstitial kidney disease due to uromodulin mutations (ADTKD-UMOD) is one of the leading hereditary kidney diseases. UMOD is largely expressed in the thick ascending limb (TAL) tubular cells, and the p.His177_Arg185del in-frame deletion is one of the most prevalent human mutations. Currently there is no treatment for ADTKD.

Methods

CRISPR/Cas9 was utilized to generate an ADTKD-UMOD mouse model carrying Umod p.Tyr178_Arg186del, analogous to human p.His177_Arg185del. Inducible tubular-specific MANF transgenic and TAL-specific MANF knockout mice were also generated. Meanwhile, stable HEK cell line harboring WT or p.His177_Arg185del was established. RNA sequencing was performed on isolated primary TAL cells. Immunoblot, q-PCR, immunofluorescence staining and electron microscopy were employed. Mitochondrial function was assessed by Oroboros high resolution respirometry and mitochondrial ROS was monitored by 68Ga-Galuminox PET/CT in live animals for the first time.

Results

We find activated endoplasmic reticulum (ER) stress, severely impaired autophagy/mitophagy and dysfunctional mitochondria in the mutant TAL tubules, and mitochondrial DNA leaking to cytosol leads to activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) inflammatory pathway and cell death in the Umod Y178-R186del mice. Mesencephalic astrocyte-derived neurotrophic factor (MANF), a novel ER stress-regulated secreted protein is induced in both mutant kidney and kidney biopsies with the mutation. We demonstrate that genetic ablation of MANF in TALs worsens autophagy and mitochondria failure, and exacerbates kidney fibrosis. Conversely, tubular overexpression of MANF after the onset of disease stimulates autophagy/mitophagy through activation of p-AMPK-FOXO3 axis, leading to increased autophagic clearance of mutant UMOD. Moreover, MANF induction promotes mitochondrial biogenesis and oxidative phosphorylation, as well as alleviates cGAS-STING signaling, thereby improving kidney function.

Conclusion

Our findings uncover a previously unknown mechanism of MANF action that can activate autophagy and protect mitochondrial function in ADTKD.

Funding

  • NIDDK Support