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Kidney Week

Abstract: TH-PO690

Novel Screen to Identify Kinase Drug Targets for Autosomal Dominant Polycystic Kidney Disease

Session Information

Category: Genetic Diseases of the Kidney

  • 1001 Genetic Diseases of the Kidney: Cystic

Authors

  • Soomro, Irfana H., NYU Langone Medical Center, NY, New York, United States
  • Hong, Aram, NYU, New York, New York, United States
  • Li, Zhai, NYUMC, New York, New York, United States
  • Skolnik, Edward Y., New York University of Medicine, New York, New York, United States
Background


Activation of kinases and the downstream signaling pathways they activate is central to the pathogenesis of cyst growth in ADPKD. However, while the human kinome consists of more than 500 kinases, only a fraction of these kinases have been tested to determine if they play a role in ADPKD pathogenesis. As a result, there are likely many kinases that are more active in ADPKD kidneys that play prominent roles in disease that are yet-to-be discovered and may be good therapeutic targets. We have now adapted a novel approach to broadly screen PKD kidneys in an unbiased manner for kinases that are more active in PKD kidneys compared with wild type kidneys.

Methods

Active kinases were affinity captured by passing wild type and PKD kidney lysates through columns containing multiplexed kinase inhibitor beads. Bound kinases were then identified by LC separation followed by tandem mass spectrometry. Increase in kinase expression and/or activity was validated by Western Blot and the specific kidney cells expressing the kinase was determined by Immunohistochemistry. The relevance of a kinase to cyst growth in vivo was assessed by treating PKD mutant mice with specific kinase inhibitors and/or genetically by generating kinase knockouts using CRISPR/Cas9.

Results

We identified a number of both known and unknown kinases specifically upregulated or downregulated in mouse PKD kidneys. Focal adhesion Kinase (FAK) is one of the promising kinase identified in the screen. We found that FAK and phospho-FAK expression was upregulated in cyst lining epithelium in PKD kidneys. Consistent with FAK playing an important role in cyst growth, treatment of Pkhd1-Cre;Pkd1fl/fl mice with the FAK inhibitor VS-4718 slowed cyst growth, preserved renal function, and prolonged survival. VS-4718 treatment led to the inhibition of multiple signaling pathways that could account for the therapeutic benefit including paxillin, p130cas, AKT and Stat3.

Conclusion

This is the first time PKD kidneys have been probed proteomically in an unbiased manner to identify the full range of kinases that are more active in PKD kidneys with the goal of identifying new therapeutic targets. So far we have identified FAK as a potential drug target that can slow cyst growth and preserve renal function and are currently in the process of working up several other promising kinases

Funding

  • Private Foundation Support