Abstract: FR-OR10
Crystalluria Impairs Macrophage Function During Kidney Stone Formation
Session Information
- Advances in Mineral Metabolism and Nephrolithiasis
November 04, 2022 | Location: W314, Orange County Convention Center‚ West Building
Abstract Time: 05:51 PM - 06:00 PM
Category: Bone and Mineral Metabolism
- 402 Bone and Mineral Metabolism: Clinical
Authors
- Mitchell, Tanecia, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
- Laurence, Emma, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
- Kumar, Parveen, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
Background
Approximately 10% of the United States population will form a kidney stone in their lifetime. Increased consumption of oxalate-rich meals is positively associated with urinary oxalate levels and stone formation. Macrophages are essential for removing crystals, which are the precursors to kidney stones, and rely on mitochondria and lysosomes to carry out their function. Interleukin-10 (IL-10) is an anti-inflammatory cytokine that regulates mitochondrial function in macrophages. The purpose of this study was to determine whether urinary nanocrystals reduce macrophage metabolism, signaling, and mitochondrial/lysosomal function. We hypothesize human urinary nanocrystals impair macrophage metabolism, IL-10 signaling, and mitochondrial quality control.
Methods
Ten adult healthy subjects and CaOx stone formers consumed controlled high oxalate diets for 4 days. Urine was collected 24 hours before and after the dietary regimen. Urinary nanocrystals were characterized using nanoparticle tracking analysis and subsequently exposed to macrophages (human and THP-1 monocyte-derived macrophages) with or without exogenous IL-10 (40 ng/ml) for 24 hours. Cell viability was measured using the MTT assay and metabolism was assessed using the Seahorse XF Analyzer. Mitochondrial and lysosomal gene expression and protein levels were determined using real-time quantitative reverse transcription-PCR, western blotting, or confocal microscopy. Mitochondrial reactive oxygen species (ROS) levels, mitochondrial membrane potential, and lysosomal activity were assessed using fluorescent-based plate reader assays.
Results
Our results show that high oxalate diets stimulate urinary nanocrystals and these crystals impair macrophage viability, metabolism, IL-10 and ROS signaling, mitochondrial and lysosomal gene expression and protein levels, and mitochondrial quality control. Further, we determined that exogenous IL-10 treatment prevented these outcomes.
Conclusion
These findings suggest that urinary nanocrystals impact macrophage function and this may reduce their ability to prevent kidney stone formation and growth. Future studies will determine mechanisms contributing to IL-10 signaling impairment in macrophages following oxalate exposure and test potential therapies to improve macrophage function during kidney stone formation.
Funding
- NIDDK Support