The NKCC1 ion transporter modulates microglial phenotype and inflammatory response to brain injury in a cell-autonomous manner

PLoS Biol. 2022 Jan 27;20(1):e3001526. doi: 10.1371/journal.pbio.3001526. eCollection 2022 Jan.


The NKCC1 ion transporter contributes to the pathophysiology of common neurological disorders, but its function in microglia, the main inflammatory cells of the brain, has remained unclear to date. Therefore, we generated a novel transgenic mouse line in which microglial NKCC1 was deleted. We show that microglial NKCC1 shapes both baseline and reactive microglia morphology, process recruitment to the site of injury, and adaptation to changes in cellular volume in a cell-autonomous manner via regulating membrane conductance. In addition, microglial NKCC1 deficiency results in NLRP3 inflammasome priming and increased production of interleukin-1β (IL-1β), rendering microglia prone to exaggerated inflammatory responses. In line with this, central (intracortical) administration of the NKCC1 blocker, bumetanide, potentiated intracortical lipopolysaccharide (LPS)-induced cytokine levels. In contrast, systemic bumetanide application decreased inflammation in the brain. Microglial NKCC1 KO animals exposed to experimental stroke showed significantly increased brain injury, inflammation, cerebral edema and worse neurological outcome. Thus, NKCC1 emerges as an important player in controlling microglial ion homeostasis and inflammatory responses through which microglia modulate brain injury. The contribution of microglia to central NKCC1 actions is likely to be relevant for common neurological disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Edema / chemically induced
  • Brain Edema / genetics*
  • Brain Edema / metabolism
  • Brain Edema / pathology
  • Brain Injuries / chemically induced
  • Brain Injuries / genetics*
  • Brain Injuries / metabolism
  • Brain Injuries / pathology
  • Bumetanide / pharmacology
  • Embryo, Mammalian
  • Gene Expression Regulation
  • Hippocampus / drug effects
  • Hippocampus / metabolism
  • Hippocampus / pathology
  • Inflammasomes / drug effects
  • Inflammasomes / metabolism
  • Inflammation
  • Injections, Intraventricular
  • Interleukin-1beta / genetics
  • Interleukin-1beta / metabolism
  • Lipopolysaccharides / administration & dosage
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microglia / drug effects
  • Microglia / metabolism*
  • Microglia / pathology
  • NLR Family, Pyrin Domain-Containing 3 Protein / genetics
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
  • Neural Stem Cells / drug effects
  • Neural Stem Cells / metabolism
  • Neural Stem Cells / pathology
  • Phenotype
  • Solute Carrier Family 12, Member 2 / deficiency
  • Solute Carrier Family 12, Member 2 / genetics*
  • Stroke / chemically induced
  • Stroke / genetics*
  • Stroke / metabolism
  • Stroke / pathology


  • IL1B protein, mouse
  • Inflammasomes
  • Interleukin-1beta
  • Lipopolysaccharides
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse
  • Slc12a2 protein, mouse
  • Solute Carrier Family 12, Member 2
  • Bumetanide

Grant support

This work was supported by “Momentum” research grant from the Hungarian Academy of Sciences (LP2016-4/2016 to A.D.; and ERC-CoG 724994 (to A.D.;, with contribution from 2019-2.1.7-ERA-NET-2020-00004 ( Additionally, this work was funded by Hungarian National Scientific Research Fund (NKFIH-OTKA Grant No. K131844 to S.B.), the János Bolyai Research Scholarship of the Hungarian Academy of Sciences (to C.C. and N.L., BO/00558/19/5;, ÚNKP-20-3-II (to B.P.) and ÚNKP-21-5 (to C.C. and N.L.; of the New National Excellence Program of the Ministry for Innovation and Technology, Hungary; German Research Foundation (SPP 1665; and the Federal Ministry of Education and Research (NEURON ACRoBAT 01EW1706) to C.A.H.; and the Academy of Finland and Sigrid Jusélius Foundation ( to K.K.. Prepared with the professional support of the Doctoral Scholarship Program of the Cooperative Doctoral Program of the Ministry of Innovation and Technology Financed from The National Research, Development and Innovation Fund (to B.P.). A.A. holds a Stipendium Hungaricum Scholarship from the Government of Hungary ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.