Kidney Week

Abstract: SA-PO183

Myeloid Cell Deletion of the Cationic Channel TRPM2, a Target of Uromodulin Inhibition, Is Protective in Murine Sepsis

Session Information

• AKI: Mechanisms - III
  November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• LaFavers, Kaice Arminda, Indiana University School of Medicine, Indianapolis, Indiana, United States

Kaice Arminda LaFavers,

• Sabo, Angela R., Indiana University School of Medicine, Indianapolis, Indiana, United States

Angela R. Sabo,

• Rhodes, George, Indiana University School of Medicine, Indianapolis, Indiana, United States

George Rhodes,

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

Tarek M. El-Achkar,

Background

Kidney-derived uromodulin is protective in a mouse model of sepsis, where it promotes proper myeloid cell function in the response to infection. One of the ion channel targets of uromodulin inhibition, cationic channel TRPM2, is expressed on myeloid cells and plays a role in their function. We therefore hypothesized that uromodulin modulates myeloid cell function in sepsis via TRPM2 and that its loss on myeloid cells would be protective in this setting.

Methods

A myeloid specific knockout of TRPM2 was generated by crossing a TRPM2^fl/fl mouse with a myeloid cell specific Cre recombinase mouse (LysM^Cre). The resulting mice (TRPM2^fl/fl LysM^Cre/+) and their littermate controls (TRPM2^fl/fl LysM^+/+) were utilized in the cecal ligation and puncture model of sepsis. Animals were euthanized at various time points post-surgery to assess survival or to collect tissue and serum for imaging and biochemical studies. Immune cell distribution within the kidney will be measured using the Akoya Phenocycler system and immune cell signaling within the kidney is being analyzed by single-cell RNA-sequencing on the 10X Genomics platform.

Results

TRPM2^fl/fl LysM^Cre/+ mice have increased survival and decreased sepsis severity at 48 hours post-surgery compared to TRPM2^fl/fl LysM^+/+ controls. This is despite similar bacterial burden within the peritoneal organs of both genotypes at 24 hours post-surgery. To determine the potential mechanism for increased survival in TRPM2^fl/fl LysM^Cre/+ animals, we harvested kidneys at 10 hours post-surgery and isolated immune cells for single cell RNA-sequencing. We found a reduction in transcriptional markers of immune defense in many cell types of TRPM2^fl/fl LysM^Cre/+ mice. Markers of lymphocyte and natural kill cell mediated immunity were decreased despite the lack of expression of LysM in adaptive and innate lymphoid cells. This suggests that loss of TRPM2 on myeloid cell cells is blocking crosstalk between cells within the immune system to promote immune tolerance.

Conclusion

Myeloid cell knockout of TRPM2 is protective in a mouse model of sepsis. This is consistent with the previously described protective role for uromodulin in sepsis, as uromodulin is an inhibitor of TRPM2. This protection could be due to an increase in immune tolerance and prevention of death from septic shock.

Funding

• NIDDK Support – Dialysis Clinic, Inc.