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Updated: Oct 5, 2025
Characterization and Isolation of Mouse Primary Microglia by Density Gradient Centrifugation
Published on: February 16, 2018
The NKCC1 ion transporter modulates microglial phenotype and inflammatory response to brain injury in a
Krisztina Tóth1,2, Nikolett Lénárt1, Péter Berki2,3
1Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.
Abstract:
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.
Insights
The NKCC1 transporter in brain
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- The NKCC1 ion transporter's role in neurological disorders is known, but its function in microglia remains unclear.
- Microglia are the primary immune cells in the central nervous system, crucial for brain inflammation and injury responses.
Purpose of the Study:
- To investigate the specific function of NKCC1 in microglia.
- To determine how microglial NKCC1 influences brain inflammation and neurological injury.
Main Methods:
- Generation of a novel transgenic mouse line with microglial-specific NKCC1 deletion (microglial NKCC1 KO).
- Assessment of microglial morphology, inflammatory responses (IL-1β, NLRP3 inflammasome), and response to LPS stimulation.
- Evaluation of brain injury, inflammation, and neurological outcomes in microglial NKCC1 KO mice subjected to experimental stroke.
- Pharmacological inhibition of NKCC1 using bumetanide (central and systemic administration).
Main Results:
- Microglial NKCC1 regulates microglial morphology, process extension, and volume adaptation in a cell-autonomous manner.
- NKCC1 deficiency in microglia leads to NLRP3 inflammasome priming and increased IL-1β production, enhancing inflammatory responses.
- Central NKCC1 blockade potentiates LPS-induced inflammation, while systemic blockade reduces it.
- Microglial NKCC1 KO mice exhibit exacerbated brain injury, inflammation, edema, and worse outcomes following experimental stroke.
Conclusions:
- NKCC1 is a critical regulator of microglial ion homeostasis and inflammatory function.
- Microglial NKCC1 plays a significant role in modulating brain injury, particularly in conditions like stroke.
- Targeting microglial NKCC1 may offer therapeutic potential for neurological disorders characterized by neuroinflammation.
