title: Heterologous expression of a glial Kir channel (KCNJ10) in a neuroblastoma spinal cord (NSC-34) cell line.
abstract: Heterologous expression of Kir channels offers a tool to modulate excitability of neurons which provide insight into Kir channel functions in general. Inwardly-rectifying K+ channels (Kir channels) are potential candidate proteins to hyperpolarize neuronal cell membranes. However, heterologous expression of inwardly-rectifying K+ channels has previously proven to be difficult. This was mainly due to a high toxicity of the respective Kir channel expression. We investigated the putative role of a predominantly glial-expressed, weakly rectifying Kir channel (Kir4.1 channel subunit; KCNJ10) in modulating electrophysiological properties of a motoneuron-like cell culture (NSC-34). Transfection procedures using an EGFP-tagged Kir4.1 protein in this study proved to have no toxic effects on NSC-34 cells. Using whole cell-voltage clamp, a substantial increase of inward rectifying K+ currents as well as hyperpolarization of the cell membrane was observed in Kir4.1-transfected cells. Na+ inward currents, observed in NSC-34 controls, were absent in Kir4.1/EGFP motoneuronal cells. The Kir4.1-transfection did not influence the NaV1.6 sodium channel expression. This study demonstrates the general feasibility of a heterologous expression of a weakly inward-rectifying K+ channel (Kir4.1 subunit) and shows that in vitro overexpression of Kir4.1 shifts electrophysiological properties of neuronal cells to a more glial-like phenotype and may therefore be a candidate tool to dampen excitability of neurons in experimental paradigms.
authors.affiliation: Department of Neurology, Georg-August-University, Göttingen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Zschüntzsch
authors.forename: S
authors.initials: S
authors.lastname: Schütze
authors.forename: S
authors.initials: S
authors.lastname: Hülsmann
authors.forename: P
authors.initials: P
authors.lastname: Dibaj
authors.forename: C
authors.initials: C
authors.lastname: Neusch
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008564:Membrane Potentials; D051379:Mice; D062557:NAV1.6 Voltage-Gated Sodium Channel / Q000378:metabolism; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013120:Spinal Cord Neoplasms / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D000098854:Kcnj10 Channel
chemical_list: D000098854:Kcnj10 Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D024661:Potassium Channels, Inwardly Rectifying; D011993:Recombinant Fusion Proteins; C491046:Scn8a protein, mouse; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins