P2X4 receptor exacerbates ischemic AKI and induces renal proximal tubular NLRP3 inflammasome signaling

FASEB J. 2020 Apr;34(4):5465-5482. doi: 10.1096/fj.201903287R. Epub 2020 Feb 21.

Abstract

We tested the hypothesis that the P2X4 purinergic receptor (P2X4) exacerbates ischemic acute kidney injury (AKI) by promoting renal tubular inflammation after ischemia and reperfusion (IR). Supporting this, P2X4-deficient (KO) mice were protected against ischemic AKI with significantly attenuated renal tubular necrosis, inflammation, and apoptosis when compared to P2X4 wild-type (WT) mice subjected to renal IR. Furthermore, WT mice treated with P2X4 allosteric agonist ivermectin had exacerbated renal IR injury whereas P2X4 WT mice treated with a selective P2X4 antagonist (5-BDBD) were protected against ischemic AKI. Mechanistically, induction of kidney NLRP3 inflammasome signaling after renal IR was significantly attenuated in P2X4 KO mice. A P2 agonist ATPγS increased NLRP3 inflammasome signaling (NLRP3 and caspase 1 induction and IL-1β processing) in isolated renal proximal tubule cells from WT mice whereas these increases were absent in renal proximal tubules isolated from P2X4 KO mice. Moreover, 5-BDBD attenuated ATPγS induced NLRP3 inflammasome induction in renal proximal tubules from WT mice. Finally, P2X4 agonist ivermectin induced NLRP3 inflammasome and pro-inflammatory cytokines in cultured human proximal tubule cells. Taken together, our studies suggest that renal proximal tubular P2X4 activation exacerbates ischemic AKI and promotes NLRP3 inflammasome signaling.

Keywords: apoptosis; inflammasome; inflammation; ischemia and reperfusion injury; necrosis; neutrophil.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury / etiology
  • Acute Kidney Injury / metabolism
  • Acute Kidney Injury / pathology*
  • Animals
  • Apoptosis
  • Cytokines / metabolism
  • Inflammasomes / metabolism*
  • Inflammation / etiology
  • Inflammation / metabolism
  • Inflammation / pathology*
  • Kidney Tubules, Proximal / immunology
  • Kidney Tubules, Proximal / metabolism
  • Kidney Tubules, Proximal / pathology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • NLR Family, Pyrin Domain-Containing 3 Protein / genetics
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism*
  • Receptors, Purinergic P2X4 / physiology*
  • Reperfusion Injury / complications*

Substances

  • Cytokines
  • Inflammasomes
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse
  • Receptors, Purinergic P2X4