Development of a QPatch automated electrophysiology assay for identifying KCa3.1 inhibitors and activators

David Paul Jenkins, Weifeng Yu, Brandon M. Brown, Lars Damgaard Løjkner, Heike Wulff

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The intermediate-conductance Ca2+-activated K+ channel KCa3.1 (also known as KCNN4, IK1, or the Gárdos channel) plays an important role in the activation of T and B cells, mast cells, macrophages, and microglia by regulating membrane potential, cellular volume, and calcium signaling. KCa3.1 is further involved in the proliferation of dedifferentiated vascular smooth muscle cells and fibroblast and endothelium-derived hyperpolarization responses in the vascular endothelium. Accordingly, KCa3.1 inhibitors are therapeutically interesting as immunosuppressants and for the treatment of a wide range of fibroproliferative disorders, whereas KCa3.1 activators constitute a potential new class of endothelial function preserving antihypertensives. Here, we report the development of QPatch assays for both KCa3.1 inhibitors and activators. During assay optimization, the Ca2+ sensitivity of KCa3.1 was studied using varying intracellular Ca2+ concentrations. A free Ca2+ concentration of 1 μM was chosen to optimally test inhibitors. To identify activators, which generally act as positive gating modulators, a lower Ca2+ concentration (∼200 nM) was used. The QPatch results were benchmarked against manual patch-clamp electrophysiology by determining the potency of several commonly used KCa3.1 inhibitors (TRAM-34, NS6180, ChTX) and activators (EBIO, riluzole, SKA-31). Collectively, our results demonstrate that the QPatch provides a comparable but much faster approach to study compound interactions with KCa3.1 channels in a robust and reliable assay.

Original languageEnglish (US)
Pages (from-to)551-560
Number of pages10
JournalAssay and Drug Development Technologies
Volume11
Issue number9-10
DOIs
StatePublished - Dec 1 2013

Fingerprint

Riluzole
Charybdotoxin
Calcium-Activated Potassium Channels
Calcium Signaling
Electrophysiology
Vascular Endothelium
Microglia
Immunosuppressive Agents
Vascular Smooth Muscle
Mast Cells
Membrane Potentials
Antihypertensive Agents
Smooth Muscle Myocytes
Endothelium
B-Lymphocytes
Fibroblasts
Macrophages
T-Lymphocytes
naphtho(1,2-d)thiazol-2-ylamine
TRAM 34

ASJC Scopus subject areas

  • Drug Discovery
  • Molecular Medicine

Cite this

Development of a QPatch automated electrophysiology assay for identifying KCa3.1 inhibitors and activators. / Jenkins, David Paul; Yu, Weifeng; Brown, Brandon M.; Løjkner, Lars Damgaard; Wulff, Heike.

In: Assay and Drug Development Technologies, Vol. 11, No. 9-10, 01.12.2013, p. 551-560.

Research output: Contribution to journalArticle

Jenkins, David Paul ; Yu, Weifeng ; Brown, Brandon M. ; Løjkner, Lars Damgaard ; Wulff, Heike. / Development of a QPatch automated electrophysiology assay for identifying KCa3.1 inhibitors and activators. In: Assay and Drug Development Technologies. 2013 ; Vol. 11, No. 9-10. pp. 551-560.
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