Delayed Rectifier and A-Type Potassium Channels Associated with Kv 2.1 and Kv 4.3 Expression in Embryonic Rat Neural Progenitor Cells

Dean O Smith,Ronald E Kalil,Julie L Rosenheimer

doi:10.1371/journal.pone.0001604

Dean O Smith, Ronald E Kalil + Show 1 more

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https://doi.org/10.1371/journal.pone.0001604

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Abstract

BackgroundBecause of the importance of voltage-activated K+ channels during embryonic development and in cell proliferation, we present here the first description of these channels in E15 rat embryonic neural progenitor cells derived from the subventricular zone (SVZ). Activation, inactivation, and single-channel conductance properties of recorded progenitor cells were compared with those obtained by others when these Kv gene products were expressed in oocytes.Methodology/Principal FindingsNeural progenitor cells derived from the subventricular zone of E15 embryonic rats were cultured under conditions that did not promote differentiation. Immunocytochemical and Western blot assays for nestin expression indicated that almost all of the cells available for recording expressed this intermediate filament protein, which is generally accepted as a marker for uncommitted embryonic neural progenitor cells. However, a very small numbers of the cells expressed GFAP, a marker for astrocytes, O4, a marker for immature oligodendrocytes, and βIII-tubulin, a marker for neurons. Using immunocytochemistry and Western blots, we detected consistently the expression of Kv2.1, and 4.3. In whole-cell mode, we recorded two outward currents, a delayed rectifier and an A-type current.Conclusions/SignificanceWe conclude that Kv2.1, and 4.3 are expressed in E15 SVZ neural progenitor cells, and we propose that they may be associated with the delayed-rectifier and the A-type currents, respectively, that we recorded. These results demonstrate the early expression of delayed rectifier and A-type K+ currents and channels in embryonic neural progenitor cells prior to the differentiation of these cells.

Highlights

Embryonic neural progenitor cells from the developing brain have been isolated, cultured, and shown to differentiate into neurons, astrocytes and oligodendrocytes [1,2]
We have focused on neuronal K+ channels in undifferentiated Embryonic neural progenitor cells (eNPC), because of their importance during embryonic development [11,12] and in cell proliferation [4,13]
Cytological Characteristics of Recorded eNPC Within 24–48 hours after seeding E15 eNPC derived from the subventricular zone (SVZ) in untreated tissue culture flasks, the cells aggregated to form neurospheres (Figure 1 A)

Summary

Introduction

Embryonic neural progenitor cells (eNPC) from the developing brain have been isolated, cultured, and shown to differentiate into neurons, astrocytes and oligodendrocytes [1,2]. Neurons derived in culture from rat and human eNPC cells express voltage-gated ionic currents indicative of physiological function [4]. Action potentials were not detected in immature neurons derived from progenitor cells in the embryonic (E20) rat cerebellum [8] or in cells from the adult rat subventricular zone [9]. Because of the importance of voltage-activated K+ channels during embryonic development and in cell proliferation, we present here the first description of these channels in E15 rat embryonic neural progenitor cells derived from the subventricular zone (SVZ). Activation, inactivation, and single-channel conductance properties of recorded progenitor cells were compared with those obtained by others when these Kv gene products were expressed in oocytes

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Conclusion