Kidney Week

Abstract: PO1351

Ultrabright Plasmonic-Fluor Nanolabel-Enabled Detection of a Urinary Endoplasmic Reticulum Stress Biomarker in Autosomal Dominant Tubulointerstitial Kidney Disease

Session Information

• Genetic Diseases of the Kidneys: Non-Cystic - II
  November 04, 2021 | Location: On-Demand, Virtual Only
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

• 1002 Genetic Diseases of the Kidneys: Non-Cystic

Authors

• Kim, Yeawon, Washington University in St Louis, St louis, Missouri, United States

Yeawon Kim, MS

• Wang, Zheyu, Washington University in St Louis, St louis, Missouri, United States

Zheyu Wang,

• Li, Chuang, Washington University in St Louis, St louis, Missouri, United States

Chuang Li,

• Kidd, Kendrah O., Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States

Kendrah O. Kidd,

• Wang, Yixuan, Washington University in St Louis, St louis, Missouri, United States

Yixuan Wang,

• Johnson, Bryce G., Pfizer Inc, New York, New York, United States

Bryce G. Johnson,

• Kmoch, Stanislav, Univerzita Karlova, Praha, Czechia

Stanislav Kmoch,

• Morrissey, Jeremiah J., Washington University in St Louis, St louis, Missouri, United States

Jeremiah J. Morrissey,

• Bleyer, Anthony J., Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States

Anthony J. Bleyer,

• Duffield, Jeremy Stuart, Prime Medicine, Cambridge, Massachusetts, United States

Jeremy Stuart Duffield,

• Singamaneni, Srikanth, Washington University in St Louis, St louis, Missouri, United States

Srikanth Singamaneni,

• Chen, Ying Maggie, Washington University in St Louis, St louis, Missouri, United States

Ying Maggie Chen,

Background

Autosomal dominant tubulointerstitial kidney disease (ADTKD)-UMOD is one of the most common non-polycystic genetic kidney disease, but it remains unrecognized due to its clinical heterogeneity and lack of screening test. Moreover, clinical feature being a poor predictor of the disease outcome further highlights the need for development of mechanistic biomarkers in ADTKD. However, low abundant urinary proteins secreted by thick ascending limb (TAL) cells, where uromodulin (UMOD) is synthesized, have posed a challenge on detection of biomarkers in ADTKD-UMOD.

Methods

We have utilized CRISPR/Cas9-generated mice with Umod-C147W mutation, analogous to human UMOD-C148W mutation, and ADTKD-UMOD patients to discover a novel endoplasmic reticulum (ER) stress biomarker. In addition, we have developed an ultrasensitive, plasmon-enhanced fluorescence-linked immunosorbent assay (p-FLISA) to detect the urinary biomarker in ADTKD patients by harnessing a newly invented ultrabright fluorescent nanoconstruct, termed “plasmonic fluor (PF)” (Nat Biomed Eng 2020).

Results

In the murine model and patients with ADTKD-UMOD, we find that immunoglobulin heavy chain-binding protein (BiP), an ER chaperone, was exclusively upregulated by mutant UMOD in TAL and easily detected by Western blot in the urine at an early stage of disease. However, even the most sensitive ELISA failed to detect urinary BiP in affected individuals. We therefore developed the ultrasensitive p-FLISA, which demonstrated that urinary BiP excretion was significantly elevated in ADTKD-UMOD patients compared with unaffected controls. Moreover, urinary BiP elevation was positively correlated with decline of kidney function in ADTKD-UMOD patients.

Conclusion

By developing the ultrasensitive p-FLISA, we have identified secreted BiP as a novel urinary ER stress biomarker with potential utility in risk stratification, prediction of disease progression and guidance of ER-targeted therapies in ADTKD.

Funding

• NIDDK Support