Downregulation of the Na/K-ATPase pump by leptospiral glycolipoprotein activates the NLRP3 inflammasome

J Immunol. 2012 Mar 15;188(6):2805-14. doi: 10.4049/jimmunol.1101987. Epub 2012 Feb 8.

Abstract

Leptospira interrogans is responsible for a zoonotic disease known to induce severe kidney dysfunction and inflammation. In this work, we demonstrate that L. interrogans induces NLRP3 inflammasome-dependent secretion of IL-1β through the alteration of potassium transport in bone marrow-derived macrophages. Lysosome destabilization also contributed to the IL-1β production upon stimulation with live, but not dead, bacteria. Using bone marrow-derived macrophages from various TLRs and nucleotide-binding oligomerization domain-deficient mice, we further determined that IL-1β production was dependent on TLR2 and TLR4, suggesting a participation of the leptospiral LPS to this process. Hypokaliemia in leptospirosis has been linked to the presence of glycolipoprotein, a cell wall component of L. interrogans that is known to inhibit the expression and functions of the Na/K-ATPase pump. We show in this study that glycolipoprotein activates the inflammasome and synergizes with leptospiral LPS to produce IL-1β, mimicking the effect of whole bacteria. These results were confirmed in vivo, as wild-type mice expressed more IL-1β in the kidney than TLR2/4-deficient mice 3 d postinfection with L. interrogans. Collectively, these findings provide the first characterization, to our knowledge, of bacteria-induced activation of the NLRP3 inflammasome through the downregulation of a specific host potassium transporter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / immunology
  • Bacterial Proteins / metabolism*
  • Blotting, Western
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism*
  • Down-Regulation
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Inflammasomes / immunology
  • Inflammasomes / metabolism*
  • Interleukin-1beta / biosynthesis
  • Interleukin-1beta / immunology
  • Leptospira / immunology
  • Leptospira / metabolism
  • Leptospirosis / immunology
  • Leptospirosis / metabolism*
  • Macrophages / immunology
  • Macrophages / metabolism*
  • Macrophages / microbiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sodium-Potassium-Exchanging ATPase / metabolism*

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Inflammasomes
  • Interleukin-1beta
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse
  • extracellular slime proteins, bacterial
  • Sodium-Potassium-Exchanging ATPase