A noninvasive optical approach for assessing chloride extrusion activity of the K-Cl cotransporter KCC2 in neuronal cells
Abstract
Background: Cation-chloride cotransporters (CCCs) are indispensable for maintaining chloride homeostasis in multiple cell types, but K-Cl cotransporter KCC2 is the only CCC member with an exclusively neuronal expression in mammals. KCC2 is critical for rendering fast hyperpolarizing responses of ionotropic.-aminobutyric acid and glycine receptors in adult neurons, for neuronal migration in the developing central nervous system, and for the formation and maintenance of small dendritic protrusions-dendritic spines. Deficit in KCC2 expression and/or activity is associated with epilepsy and neuropathic pain, and effective strategies are required to search for novel drugs augmenting KCC2 function. Results: We revised current methods to develop a noninvasive optical approach for assessing KCC2 transport activity using a previously characterized genetically encoded chloride sensor. Our protocol directly assesses dynamics of KCC2-mediated chloride efflux and allows measuring genuine KCC2 activity with good spatial and temporal resolution. As a proof of concept, we used this approach to compare transport activities of the two known KCC2 splice isoforms, KCC2a and KCC2b, in mouse neuronal Neuro-2a cells. Conclusions: Our noninvasive optical protocol proved to be efficient for assessment of furosemide-sensitive chloride fluxes. Transport activities of the N-terminal splice isoforms KCC2a and KCC2b obtained by the novel approach matched to those reported previously using standard methods for measuring chloride fluxes.Peer reviewe- Article
- publishedVersion
- Genetically encoded chloride sensor
- Slc12a5 gene
- KCC2
- Inhibition
- GABA
- GREEN FLUORESCENT PROTEIN
- GENETICALLY-ENCODED CHLORIDE
- THROUGHPUT FUNCTIONAL ASSAY
- PRESYNAPTIC NERVE-TERMINALS
- INTRACELLULAR CHLORIDE
- HIPPOCAMPAL-NEURONS
- RAT-BRAIN
- SYNAPTIC INHIBITION
- POTASSIUM CHANNELS
- NEUROPATHIC PAIN
- 3112 Neurosciences
- 3124 Neurology and psychiatry