Abstract: TH-PO1069

P2X7 Receptor Stimulation Is Not Required for Oxalate Crystal-Induced Kidney Injury

Session Information

Category: Mineral Disease

  • 1204 Mineral Disease: Nephrolithiasis

Authors

  • Luz, Hannah Lea, University of Erlangen-Nuremberg, Erlangen, Germany
  • Reichel, Martin, University of Erlangen-Nuremberg, Erlangen, Germany
  • Eckardt, Kai-Uwe, University Hospital Charite Berlin, Berlin, Germany
  • Unwin, Robert J., University College London Medical School, London, United Kingdom
  • Tam, Frederick W.K., Imperial College Kidney and Transplant Institute, London, United Kingdom
  • Knauf, Felix, University Hospital Charite Berlin, Berlin, Germany
Background

Oxalate crystal-induced renal inflammation is associated with progressive kidney failure due to activation of the NLRP3/CASP-1 inflammasome. It has been suggested previously that purinergic P2X7 receptor signaling is critical for crystal-induced inflammasome activation and kidney injury. Therefore, we investigated the role of the P2X7 receptor in response to crystal-induced cytokine release, inflammation, and kidney failure using in vitro and in vivo models.

Methods

Bone marrow-derived dendritic cells (BMDC) from C57BL/6 (wild-type), Casp1-/- and P2X7-/- mice were stimulated with calcium-oxalate crystals, monosodium urate crystals or ATP. Interleukin-1beta (IL-1ß) release was measured using ELISA and western blot analysis. For studies in vivo, age- and gender-matched wild-type, Casp1-/- and P2X7-/- mice were placed on a high oxalate diet to induce oxalate nephropathy. Kidney sections were analyzed for crystal deposition, tubular damage, and macrophage infiltration using F4/80 staining. Renal function was monitored by changes in plasma creatinine sampled retro-orbitally.

Results

Stimulation of BMDC from wild-type mice with oxalate crystals, urate crystals or ATP induced a robust release of IL-1ß. Treatment with the P2X7 inhibitor A740003 selectively abrogated ATP-induced, but not oxalate and urate crystal-induced IL-1ß release. In line with this finding, BMDC from P2X7-/- mice released reduced amounts of IL-1ß following stimulation with ATP, while oxalate and urate crystal-induced IL-1ß release was unaffected. In sharp contrast, BMDC from Casp1-/- mice exhibited reduced IL-1ß release following either of the three stimulants. In addition, while Casp1-/- mice were protected from crystal-induced renal failure, P2X7-/- mice demonstrated similar degrees of crystal deposition, tubular damage and inflammation when compared with WT mice. In line with these findings, increases in plasma creatinine were no different between WT and P2X7-/- mice.

Conclusion

In contrast to previous findings, our results indicate that P2X7 receptor is not required for crystal-induced CKD and it is unlikely to be a suitable therapeutic target for crystal-induced progressive kidney disease.

Funding

  • Private Foundation Support