hERG | KV11.1 | Erg Related Potassium Channel Member 2

Family:
Potassium channels

Subgroups:
Shaker (K_V1.1–K_V1.8), Shab (K_V2.1-K_V2.2), Shaw (K_V3.1–K_V3.4), Shal (K_V4.1–K_V4.3), KQT like (K_V7.1–K_V7.5), Eag related (K_V10.1-K_V10.2), Erg related (K_V11.1–K_V11.3), Elk related (K_V12.1)

Topology:
Contains six transmembrane domains (S1–S6), four single subunits form a pore, homotetramers and heterotetramers are possible.

hERG (KV11.1) Background Information

K_V11.1, better known as hERG (human Ether-à-go-go-Related Gene), contributes to the electrical activity of the heart that coordinates the heart's beating (i.e., the hERG channel mediates the repolarizing I_KR current in the cardiac action potential). When this channel's ability to conduct electrical current across the cell membrane is inhibited or compromised, either by application of drugs or by rare mutations in some families, it can result in a potentially fatal disorder called long QT syndrome; a number of clinically successful drugs in the market have had the tendency to inhibit hERG, and create a concomitant risk of sudden death, as a side-effect, which has made hERG inhibition an important antitarget that must be avoided during drug development. Due to the documented potential of QT interval prolonging drugs, the United States Food and Drug Administration issued recommendations for the establishment of a cardiac safety profile during pre-clinical drug development: ICH S7B.

hERG has also been associated with modulating the functions of some cells of the nervous system and with establishing and maintaining cancer-like features in leukemic cells.

Gene:
KCNH2

Human Protein:
UniProt Q12809

Tissue:
brain, heart

Function/ Application:
Cardiac I_KR current, cell proliferation, cell migration

Pathology:
Long QT syndrome (LQT2), SQT1, atrial fibrillation, sudden infant death syndrome, cancer

Interaction:
KCNH6/ERG2, KCNH7/ERG3, ALG10B, KCNE1, KCNE2, CANX, cAMP, caveolin-1, FHL2

Modulator:
Terfenadine, verapamil, dofetilide, cisapride, astemizole, E4031

Assays:
Patch Clamp: whole cell, room temperature, physiological temperature

Recommended Reviews:
Gutman et al. (2005) International Union of Pharmacology. LIII. Nomenclature and molecular relationships of voltage-gated potassium channels. Pharmacol Rev 57(4):473-508

Data and Applications

hERG - Application of Dofetilide

Port-a-Patch mini data and applications:
Cells were kindly provided by SB Drug Discovery.

Raw data traces of hERG (expressed in HEK cells) in control solution and in the presence of increasing concentrations of Dofetilide (top). IC₅₀ concentration response curve for an average of 3 cells is shown revealing an IC₅₀ of 161 ± 12 nM.

hERG and Temperature Control

SyncroPatch 384 data and applications:
Cells were kindly provided by Charles River Chantest

Cardiac ion channels are recommended to be recorded at Phys. Temp. (ICH S7B Q&A. 2021). On the SyncroPatch 384, measurement site, cells and solutions can be accurately temperature controlled – in the presence of physiological temperatures the hERG current kinetic is changed to a larger slope and higher amplitude.

hERG - Pharmacology at Physiological Temperature using the CiPA Protocol

SyncroPatch 384/768 PE (a predecessor model of the SyncroPatch 384) data and applications:
Cells were kindly provided by Charles River.

Screenshots of the PatchControl 384 software showing hERG current traces in response to the CiPA voltage step protocol at 35 degree Celsius. Measured on the SyncroPatch 384PE (a predecessor model of SyncroPatch 384) using perforated patch clamp methodology (Escin) and multi-hole chips (4 holes per well). The IC₅₀ value of Erythromycin of the peak current was determined as 60.5 µM.

hERG - Pharmacology of Cisapride, using the CiPA protocol

Patchliner data and applications:
Cells were kindly provided by Charles River.

The effect of cisapride on hERG currents was investigated, using the CiPA voltage step protocol. Measured on the Patchliner the perforated patch methodology (Escin) and multi-hole chips (4 holes per well) were used. The IC₅₀ value of Cisapride was determined as 112 nM.

hERG - Pharmacology using the CiPA Protocol

SyncroPatch 384/768 PE (a predecessor model of SyncroPatch 384) data and applications:
Cells were kindly provided by Charles River.

Screenshots of the PatchControl 384 software showing hERG current traces in response to the CiPA voltage step protocol. Measured on the SyncroPatch 384PE (a predecessor model of SyncroPatch 384) using whole cell patch clamp methodology and multi-hole chips (4 holes per well). The IC₅₀ value of the following compounds of the peak current was determined as 4.18 µM for Diltiazem, 37.4 nM for Terfenadine, 971 nM for Quinidine, 63 µM for Mexiletine, 431 nM for Verapamil and 4.54 µM for Ranolazine.

hERG - recordings with great stability using the CiPA step ramp protocol

SyncroPatch 384PE (a predecessor model of SyncroPatch 384) data and applications:
Cells were kindly provided by Charles River.

Cardiac Ion Channels - Pharmacology of Vandetanib

Icon CE CardioExcyte 96 and Patchliner data and applications:
Cells were kindly provided by Charles River and Cellular Dynamics.

The image on the left hand side displays the results of the blocking effect of Vandetanib on hERG, Na_V1.5, Ca_V1.2 and K_V4.3. The compound induced arrhythmia when iPSC-CM were exposed to a minimum concentration of 1 µM. Arrhytmic events were both detected in field potential recordings as well as in the impedance based contractility.

Cardiac Ion Channels - Pharmacology of Sotalol

Icon CE CardioExcyte 96 and SyncroPatch 384PE (a predecessor model of SyncroPatch 384) data and applications:
Cells were kindly provided by Charles River and Cellular Dynamics.

The image on the left hand side displays the results of the blocking effect of Sotalol on hERG. The result is in good agreement with manual patch clamp data (Crumb et al., 2016). The compound induced arrhythmia when iPSC-CM were exposed to a minimum concentration of 10 µM. Arrhytmic events were both detected in field potential recordings as well as in the impedance based contractility measurements.

hERG - Application of "Sticky Compounds"

Patchliner data and applications:
hERG expressing HEK293 cells were kindly provided by Cytomyx/Millipore.

Even sticky compounds pose no problem for the Patchliner. IC₅₀ measurements of well known sticky substances were determined on the Patchliner: Terfenadine IC₅₀ = 11.0 ± 3 nM, Flunarizine IC₅₀ 163.7 ± 19 nM and Cisapride IC₅₀8.9 ± 3 nM.

hERG - Efficient Screening

Patchliner data and applications:
Cells were kindly provided by Cytomyx/Millipore.

The effects of six different blockers (terfenadine, cisapride, E4031, astemizole, propafenone, quinidine) on hERG currents (HEK293 cells) were investigated. Expected IC₅₀ values for the different compounds were obtained. In two days, 119 full dose response curves were collected by a single person. Data was analyzed using Nanion’s Data Analysis Package, a very efficient and convenient data analysis tool!

hERG - Pharmacological Experiments at 35 °C

Port-a-Patch data and applications:
Cells were kindly provided by Cytomyx/Millipore, UK.

A full dose response curve of quinidine acting on the hERG channel was obtained at physiological temperature (35 °C). The IC₅₀ for quinidine at physiological temperature was 1.3 ± 0.2 μM (n = 5), similar to that obtained at room temperature (1.0 ± 0.03 μM, n = 3).

hERG - Good Results with "Sticky Compounds"

Port-a-Patch data and applications:
Cells were kindly provided by Cytomyx/Millipore.

Sticky compounds, such as some hERG blockers, exhibit expected IC₅₀ values with the Port-a-Patch. The concentrations of the half maximal block were: 1.27 nM (astemizole), 8.9 nM (cisapride), 163.7 nM (flunarizine) and 11.0 nM (terfenadine).

hERG - Simple Data Analysis

Patchliner data and applications:

With our analysis tools, especially programmed routines in Igor make dose response curves, raw data and current time courses easily accessible. Also, creating average dose response curves over multiple experiments - even conducted on different days - remains easy.

hERG - Block at Physiological Temperature

Patchliner data and applications:
Cells were kindly provided by Cytomyx/Millipore, UK.

The effects of erythromycin on hERG currents were tested at different temperatures. Erythromycin has been shown to block hERG channels at physiological temperature with an IC₅₀ of approx. 40 µM. However, at RT erythromycin is much less potent. For more details on these experiments please refer to the Application Note.

hERG - Temperature Control

Port-a-Patch data and applications:
Cells were kindly provided by Cytomyx/Millipore.

The image shows example traces for hERG mediated currents at 25 ± 2 °C (black) and 35 ± 2 °C (blue). The peak current amplitude was increased at 35 °C, and the rise time and decay time constants were faster at physiological temperature compared with those obtained at room temperature.

hERG - Stable Recordings with Accurate Pharmacology

SyncroPatch 384PE (a predecessor model of SyncroPatch 384) data and applications:
Cells were kindly provided by Charles River Laboratories.

Current-voltage relationship of hERG (Kv11.1) expressed in HEK293 is shown along with pharmacology of 4 hERG-active compounds. The current-voltage relationships for all 384 wells (top) using perforated patch (Escin) and multi-hole chips (4 holes per well) are shown. In all 384 wells, a hERG-mediated current was observed with peak amplitude >700 pA at -20 mV. Using a pharmacology voltage protocol, experiments were stable lasting over 20 minutes. Concentration response curves for astemizole, pimozide, cisapride and terfenadine revealed IC₅₀ values consistent with those found in the literature.

hERG - Stable Recordings

Patchliner data and applications:
Cells were kindly provided by Cytomyx/Millipore, UK.

A series of drug concentrations can be applied to each cell. The top figures show the original traces and the corresponding average dose-response curve. Five concentrations of Quinidine (0.1, 0.3, 1, 3 and 10 μM) have been applied.

The lower figure shows the corresponding Imax (-40 mV) including a wash out step and an additional application of the blocker to demonstrate the stability of whole cell recordings.

Cardiomyocytes - Time-dependent effect of Pentamidine on Cor.4U cardiomyocytes

Icon CE CardioExcyte data and applications:
Cells were kindly provided by Axiogenesis.

Time-dependent effect of Pentamidine on Cor.4U cardiomyocytes. Pentamidine clinically causes acquired long QT syndrome, which is associated with prolonged QT intervals, tachycardias, and sudden cardiac arrest. Pentamidine delays terminal repolarization in human heart by acutely blocking cardiac inward rectifier currents. At the same time, it reduces surface expression of the cardiac potassium channel IKr/human ether à-go-go-related gene (hERG).
Insets: EFP raw traces and online analysis value FPDc in the presence of Pentamidine (10 µM) at different timepoints.

hERG - Pharmacology of Bepridil, Dofetilide, Cisapride, Diltiazem (Results CiPA Phase I Study)

Patchliner data and applications:
Cells were kindly provided by Charles River.

The effect of four compounds on hERG currents were investigated, using the CiPA voltage step protocol. Measured on the Patchliner the perforated patch methodology (Escin) and multi-hole chips (4 holes per well) were used. The IC₅₀ value of Cisapride was determined as 112 nM, Bepridil as 178 nM, Dofetilide as 33.9 nM and Diltiazem as 14.5 µM.

hERG - Pharmacology of Mexiletine, Quinidine, Ondansetron, Ranolazine (Results CiPA Phase I Study)

Patchliner data and applications:
Cells were kindly provided by Charles River.

The effect of four compounds on hERG currents were investigated, using the CiPA voltage step protocol. Measured on the Patchliner the perforated patch methodology (Escin) and multi-hole chips (4 holes per well) were used. The IC₅₀ value of Mexiletine was determined as 77.3 µM, Quinidine as 1.04 µM, Ondansetron as 1.13 µM and Ranolazine as 11.9 µM.

hERG - Pharmacology of Sotalol, Terfenadine, Verapamil (Results CiPA Phase I Study)

Patchliner data and applications:
Cells were kindly provided by Charles River.

The effect of four compounds on hERG currents were investigated, using the CiPA voltage step protocol. Measured on the Patchliner the perforated patch methodology (Escin) and multi-hole chips (4 holes per well) were used. The IC₅₀ value of Sotalol was determined as 157 µM, Terfenadine as 82.8 nM and Verapamil as 485 nM.

Application Notes

Cardiac Ion Channels - "High Throughput Screening of Cardiac Ion Channels"

SyncroPatch 384PE (a predecessor model of the SyncroPatch 384) Patchliner Icon CE CardioExcyte 96 application note (2.3 MB)

hERG

hERG | KV11.1 | Erg Related Potassium Channel Member 2

hERG (KV11.1) Background Information

Data and Applications

Application Notes

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