Identifying modulators of hERG channel activity using the PatchXpress planar patch clamp.
The authors used the PatchXpress 7000A system to measure compound activity at the hERG channel using procedures that mimicked the "gold-standard" conventional whole-cell patch clamp. A set of 70 compounds, including hERG antagonists with potencies spanning 3 orders of magnitude, were tested on hERG302-HEK cells using protocols aimed at either identifying compound activity at a single concentration or obtaining compound potency from a cumulative concentration dependence paradigm. After exposure to compounds and subsequent washout of the wells to determine reversibility of the block, blockade by a reference compound served as a quality control. Electrical parameters and voltage dependence were similar to those obtained using a conventional whole-cell patch clamp. Rank order of compound potency was also comparable to that determined by conventional methods. One exception was flunarizine, a particularly lipophilic compound. The PatchXpress accurately identified the activity of 29 moderately potent antagonists, which only weakly displace radiolabeled astemizole and are false negatives in the binding assay. Finally, no false hits were observed from a collection of relatively inactive compounds. High-quality data acquisition by PatchXpress should help accelerate secondary screening for ion channel modulators and the drug discovery process.
Dubin
Adrienne E
AE
Pain and Related Disorders, Johnson and Johnson Pharmaceutical Research and Development, San Diego, CA 92121, USA. adubin@prdus.jnj.com
Nasser
Nadia
N
Rohrbacher
Jutta
J
Hermans
An N
AN
Marrannes
Roger
R
Grantham
Christopher
C
Van Rossem
Koen
K
Cik
Miroslav
M
Chaplan
Sandra R
SR
Gallacher
David
D
Xu
Jia
J
Guia
Antonio
A
Byrne
Nicholas G
NG
Mathes
Chris
C
D002460:Cell Line; D004594:Electrophysiology; D051638:Ether-A-Go-Go Potassium Channels; D006801:Humans; D020128:Inhibitory Concentration 50; D018408:Patch-Clamp Techniques / Q000295:instrumentation* / Q000379:methods*; D015221:Potassium Channels / Q000378:metabolism*; D015203:Reproducibility of Results
D051638:Ether-A-Go-Go Potassium Channels; D015221:Potassium Channels