Characterization of Voltage-Gated Potassium Channels in Human Neural Progenitor Cells

Abstract

BackgroundVoltage-gated potassium (Kv) channels are among the earliest ion channels to appear during brain development, suggesting a functional requirement for progenitor cell proliferation and/or differentiation. We tested this hypothesis, using human neural progenitor cells (hNPCs) as a model system.Methodology/Principal FindingsIn proliferating hNPCs a broad spectrum of Kv channel subtypes was identified using quantitative real-time PCR with a predominant expression of the A-type channel Kv4.2. In whole-cell patch-clamp recordings Kv currents were separated into a large transient component characteristic for fast-inactivating A-type potassium channels (IA) and a small, sustained component produced by delayed-rectifying channels (IK). During differentiation the expression of IA as well as A-type channel transcripts dramatically decreased, while IK producing delayed-rectifiers were upregulated. Both Kv currents were differentially inhibited by selective neurotoxins like phrixotoxin-1 and α-dendrotoxin as well as by antagonists like 4-aminopyridine, ammoniumchloride, tetraethylammonium chloride and quinidine. In viability and proliferation assays chronic inhibition of the A-type currents severely disturbed the cell cycle and precluded proper hNPC proliferation, while the blockade of delayed-rectifiers by α-dendrotoxin increased proliferation.Conclusions/SignificanceThese findings suggest that A-type potassium currents are essential for proper proliferation of immature multipotent hNPCs.

Voltage-gated K+ channels in adipogenic differentiation of bone marrow-derived human mesenchymal stem cells

“…First, we conducted MTT assays to determine if blocking Kv channels using TEA affected cell viability. MTT assays showed that cell viability was not significantly different following a 24 h treatment of cells with 10 mmol/L TEA, a concentration known to effectively block Kv channels [15] . We also tested the effects of TEA treatments of longer duration, performing MTT assays on cells incubated with 10 mmol/L TEA for 1, 3, 6, 9, and 12 d. In each of these time periods, TEA significantly decreased cell viability; these effects were compensated for the following experiments.…”

“…The hMSCs were seeded into 96-well plates (20 000 cells/well) and, after growing for 12 h in AM containing 20% FBS, were serum-starved by culturing for 24 h in AM containing 2% FBS. Cells were then switched to 20% FBS supplemented with 10 mmol/L TEA for 24 h. MTT assays were performed as previously described [15] . Untreated cells were used as controls.…”

“…In order to test whether Kv channels play a role in adipogenic differentiation, we blocked these channels using the nonselective K + channel blocker, TEA [15] . First, we conducted MTT assays to determine if blocking Kv channels using TEA affected cell viability.…”

Trace elements during primordial plexiform network formation in human cerebral organoids

“…During brain ontogenesis, potassium regulates proliferation of neural progenitors (21,39,40) and is maintained in heightened levels in rapidly dividing cells (41,42). As potassium currents also support the migration of early neurons over long distances due to cellular volume change (43), we can speculate from our data that potassium could be important to maintain mitotic activity at 30-days old organoids and to promote cell migration at 45-days old organoids, amongst other roles.…”

Ion channels in postnatal neurogenesis

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Moreover, the sequence diversity of ion channels, even within channel families, as well as their often multi-subunit complex three-dimensional structures provide the potential for the development of drugs that are highly selective for specific channel isoforms expressed at discrete stages of neurogenesis. This approach may be advantageous over infusion of growth factors or other bioactive peptides that are likely to have more widespread, pleiotropic effects across neuronal development.…”