Abstract: SA-PO0123
Uromodulin Inhibits the Nlrc4 Alternative Inflammasome Activation Which Regulates Macrophage-Collecting Duct Crosstalk in Early AKI
Session Information
- AKI: Mechanisms - 3
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Sabo, Angela R., Indiana University School of Medicine, Indianapolis, Indiana, United States
- Winfree, Seth, QCDx Inc., Farmington, Connecticut, United States
- Wischmeier, Dillen, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Nanamatsu, Azuma, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Khan, Shehnaz, Indiana University School of Medicine, Indianapolis, Indiana, United States
- El-Achkar, Tarek M., Indiana University School of Medicine, Indianapolis, Indiana, United States
- LaFavers, Kaice Arminda, Indiana University School of Medicine, Indianapolis, Indiana, United States
Background
Uromodulin (UMOD) is a kidney specific protein produced by the thick ascending limb (TAL). This protein plays a key protective role in modulating acute kidney injury (AKI). UMOD knockout mice have more severe injury at the peak of AKI. To study early events governing early molecular mechanisms of this UMOD effect, we sought to investigate early kidney injury using multimodal-omics approaches in WT and UMOD knockout mice.
Methods
Kidneys were harvested 6 hours after injury induced by ischemia reperfusion to perform integrative molecular and spatial analysis with single cell RNA sequencing and Co-Detection by indEXing large scale imaging using 32 markers. Integrated analysis of scRNA-seq and CODEX datasets was conducted using R and VTEA, a customized ImageJ PlugIn. Validation methods included qPCR of kidney RNA and bone marrow derived macrophages, ELISAs, Western blots, and confocal imaging.
Results
Using scRNA-seq we observed different injury/stress signatures across various segments of the nephron: oxidative injury in proximal tubules, ER stress in thick limbs, and immune activation in distal segments. UMOD deficiency enhanced the severity of injury in each nephron segment and altered the distribution and spatial neighborhoods of macrophages in relation to TALs, likely reflecting altered chemotaxis and dysregulated molecular connections. Interestingly, the absence of UMOD specifically upregulated Nlrc4-driven inflammasome signaling in macrophages, leading to increased IL-1B. Integrative analysis suggests that this signaling targets a specialized population of cortical intercalated cells that express CD8a, IL-1 receptor-1, and the pro-inflammatory cytokine IL-23. The presence of this population of CD8a+ collecting ducts was validated in external transcriptomics datasets and was also demonstrated in human CODEX imaging data. Specific inhibition of Nlrc4 activation by UMOD was also validated in bone marrow derived macrophages treated with LPS.
Conclusion
These findings suggest a model whereby UMOD inhibits the Nlrc4 inflammasome in macrophages that activates an IL-1B-dependent pro-inflammatory signalling in intercalated cells. Our findings have implications for states of UMOD deficiency, both in systemic inflammation and urinary tract defense.
Funding
- NIDDK Support