Kidney Week

Abstract: TH-PO563

Understanding the Pathogenesis of Human Kidney Stone Disease by Spatially Mapping Its Proteome

Session Information

• Bone and Mineral Metabolism: Basic
  November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 401 Bone and Mineral Metabolism: Basic

Authors

• Canela, Victor Hugo, Indiana University School of Medicine, Indianapolis, Indiana, United States

Victor Hugo Canela,

• Worcester, Elaine M., University of Chicago, Chicago, Illinois, United States

Elaine M. Worcester,

• El-Achkar, Tarek M., Indiana University, Indianapolis, Indiana, United States

Tarek M. El-Achkar,

• Williams, James, Indiana University School of Medicine, Indianapolis, Indiana, United States

James Williams,

Background

Nephrolithiasis affects approximately one-in-eleven people in the United States. A detailed hypothesis of the mechanisms of stone disease etiology remains elusive, and thus difficult to treat and prevent. The present study aims to advance the understanding of the pathogenesis of stone disease by determining the pattern of protein organization within the matrix of human kidney stones.

Methods

The approach of this work relies on an innovative technique to perform histological sectioning of calcium oxalate (CaOx) stones following demineralization. Multi-photon imaging and label-free proteomics were used on laser micro-dissected (LMD) specific regions to assess proteome identity and signaling across spatial coordinates within the stone-matrix.

Results

The average area of LMD samples for proteomic analysis was 1.64x10⁶µm², and these samples yielded an average of 629 distinct proteins. Dissection of broad regions of CaOx stone by LMD yielded similar proteins as found in larger specimens of pulverized CaOx samples. Proteins identified in LMD and pulverized samples included those involved in cell injury and repair as well as important mediators of the immune system (e.g. fatty acid synthase, osteopontin-D, complement C3). More recent results show brilliant autofluorescence of decalcified CaOx stones, which will allow LMD of distinctive regions of the stone without staining.

Conclusion

Utilization and optimization of these techniques will pave the way for a deeper understanding of kidney stone formation. Future investigation of the stone-matrix proteome will provide insight into underlying events that could become therapeutic targets to prevent stone growth.

Figure 1 LMD of human kidney stones. Demineralized stone-matrix on LMD slides were stained with methylene blue (before). Dissection of broad regions of CaOx stone by LMD (after) yielded similar proteins as found in larger specimens of pulverized CaOx stone powder (right).

Funding

• Other NIH Support