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Single-Cell Optical Action Potential Measurement in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Published: December 22nd, 2020



1Institute of Pharmacology and Toxicology, University Medical Center Goettingen, Goettingen, Germany, 2DZHK (German Center for Cardiovascular Research), Partner Site Goettingen, Germany, 3Cairn Research Ltd, Faversham, United Kingdom, 4Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Goettingen, Germany

Here we describe optical acquisition and characterization of action potentials from induced pluripotent stem cell derived cardiomyocytes using a high-speed modular photometry system.

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically carried out in low throughput. Rapid and ongoing expansion of induced pluripotent stem cell (iPSC) technology presents a new standard in cardiovascular research and alternate methods are now necessary to increase throughput of electrophysiological data at a single cell level. VF2.1Cl is a recently derived voltage sensitive dye which provides a rapid single channel, high magnitude response to fluctuations in membrane potential. It possesses kinetics superior to those of other existing voltage indicators and makes available functional data equivalent to that of traditional microelectrode techniques. Here, we demonstrate simplified, non-invasive action potential characterization in externally paced human iPSC derived cardiomyocytes using a modular and highly affordable photometry system.

Electrophysiological modeling of cardiomyocytes and the construction of efficient platforms for cardiac drug screening is essential for the development of therapeutic strategies for a variety of arrhythmic disorders. Rapid expansion of induced pluripotent stem cell (iPSC) technology has produced promising inroads into human disease modelling and pharmacological investigation using isolated patient derived cardiomyocytes (iPSC-CM). “Gold standard” techniques for electrophysiological characterization of these cells through patch-clamp (current-clamp) can quantify action potential (AP) morphology and duration, however, this method is incredibly complex and sl....

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1. Cellular preparations

NOTE: Human iPSCs used in this protocol were derived from healthy donors and differentiated in monolayers using fully defined small molecule modulation of WNT signaling and lactate purification techniques as previously described12,13,14. iPSC-CMs were maintained every 2-3 days with a culture medium outlined below.

  1. Prepare a culture medium of basal medium (RPMI 1640.......

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Figure 3
Figure 3: Optical action potential (AP) profiles of isolated native cardiomyocytes and human induced pluripotent stem cell derived cardiomyocytes (iPSC-CM). (A) Representative optical AP of a single murine cardiomyocyte (center) with Mean ± SEM of APD50 and APD90 (n = 7, right). (B) Representative optical AP of a singl.......

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Here we describe a basic protocol to easily acquire detailed AP profiles from isolated iPSC-CMs suitable for electrophysiological modelling and cardiac drug screening. We detect regular, robust APs from our sparsely seeded iPSC-CMs which suggests both indicator functionality and methodological fidelity.

Due to the wide spectrum of commercial methodologies for iPSC reprogramming and lack of standardization for cardiac differentiation protocols, iPSC based models can show immense variability in .......

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The authors would like to acknowledge Cairn Research Ltd. for their kind financial contribution which covered production costs of this publication. In addition, we thank Ms. Ines Mueller and Ms. Stefanie Kestel for their excellent technical support.

The authors’ research is supported by the German Center for Cardiovascular Research (DZHK), the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, VO 1568/3-1, IRTG1816 RP12, SFB1002 TPA13 and under Germany’s Excellence Strategy - EXC 2067/1- 390729940) and the Else-Kröner-Fresenius Stiftung (EKFS 2016_A20).


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NameCompanyCatalog NumberComments
0.25 Trypsin EDTA Gibco 25200056
B27 Supplement Gibco 17504044
CaCl2Carl Roth HN04.2
D(+)-Glucose anhydrous BioChemicaITW ReagentsA1422
Fetal Bovine Serum Gibco 10270-106
FluoVolt Membrane Potential Kit Invitrogen F10488
HEPESCarl Roth HN77.4
Matrigel BD354230
NaCl Sigma-Aldrich9265.2
Nifedipine Sigma-Aldrich21829-25-4
Penicillin/StreptomycinInvitrogen 15140
ROCK Inhibitor Y27632Stemolecule04-0012-10
RPMI 1640 Medium Gibco 61870010
Versene EDTA Gibco 15040033
495LP Dichroic Beamsplitter Chroma Technology
Axopatch 200B Amplifier Molecular Devices
Circle Coverslips, Thickness 0Thermo ScientificCB00100RA020MNT0
Digidata 1550BMolecular Devices
Dual OptoLED Power Supply Cairn Research 
ET470/40x Excitation Filter Chroma Technology
ET535/50mChroma Technology
Etched Neubauer HemacytometerHausser Scientific
Filter Cubes Cairn Research 
IX73 Inverted Microscope Olympus 
MonoLEDCairn Research 
Multiport Adaptors Cairn Research 
Myopacer Cell Stimulator IonOptix
Optomask Shutter Cairn Research 
Optoscan System ControllerCairn Research 
PH-1 Temperature Controlled Platform  Warner Instruments 
Photomultiplier Detector Cairn Research 
PMT Amplifier InsertCairn Research 
PMT Supply InsertCairn Research 
RC-26G Open Bath Chamber Warner Instruments 
SA-OLY/2AL Stage Adaptor Olympus 
T565lpxr Dichroic Beamsplitter Chroma Technology
T660lpxr Dichroic BeamsplitterChroma Technology
TC-20 Dual Channel Temperature Controller npi Electronic
UPLFLN 40X ObjectiveOlympus 
USB 3.0 Colour Camera Imaging Source
Clampex 11.1Molecular Devices 
Clampfit 11.1Molecular Devices 
IC Capture 2.4 Imaging Source 
Prism 8Graphpad

  1. Miller, E. W. Small molecule fluorescent voltage indicators for studying membrane potential. Current Opinion in Chemical Biology. 33, 74-80 (2016).
  2. Liang, P., et al. Drug screening using a library of human induced pluripotent stem cell-derived cardiomyocytes reveals disease-specific patterns of cardiotoxicity. Circulation. 127 (16), 1677-1691 (2013).
  3. Horváth, A., et al. Low resting membrane potential and low inward rectifier potassium currents are not inherent features of hiPSC-derived cardiomyocytes. Stem Cell Reports. 10 (3), 822-833 (2018).
  4. Salama, G., Morad, M. Merocyanine 540 as an optical probe of transmembrane electrical activity in the heart. Science. 191 (4226), 485-487 (1976).
  5. Hortigon-Vinagre, M., et al. The use of ratiometric fluorescence measurements of the voltage sensitive dye Di-4-ANEPPS to examine action potential characteristics and drug effects on human induced pluripotent stem cell-derived cardiomyocytes. Toxicological Sciences. 154 (2), 320-331 (2016).
  6. Blinova, K., et al. International multisite study of human-induced pluripotent stem cell-derived cardiomyocytes for drug proarrhythmic potential assessment. Cell Reports. 24 (13), 3582-3592 (2018).
  7. Miller, E. W., et al. Optically monitoring voltage in neurons by photo-induced electron transfer through molecular wires. Proceedings of the National Academy of Sciences. 109 (6), 2114-2119 (2012).
  8. Bedut, S., et al. High-throughput drug profiling with voltage- and calcium-sensitive fluorescent probes in human iPSC-derived cardiomyocytes. American Journal of Physiology-Heart and Circulatory Physiology. 311 (1), 44-53 (2016).
  9. McKeithan, W. L., et al. An automated platform for assessment of congenital and drug-induced arrhythmia with hiPSC-derived cardiomyocytes. Frontiers in Physiology. 8, 766 (2017).
  10. Duncan, G., et al. Drug-mediated shortening of action potentials in LQTS2 human induced pluripotent stem cell-derived cardiomyocytes. Stem Cells and Development. 26 (23), 1695-1705 (2017).
  11. Asakura, K., Hayashi, S., Ojima, A., Taniguchi, T., Miyamoto, N. Improvement of acquisition and analysis methods in multi-electrode array experiments with iPS cell-derived cardiomyocytes. Journal of Pharmacological and Toxicological Methods. 75, 17-26 (2015).
  12. Lian, X., et al. Directed cardiomyocyte differentiation from human pluripotent stem cells by modulating Wnt/β-catenin signaling under fully defined conditions. Nature Protocols. 8 (1), 162-175 (2013).
  13. Burridge, P. W., et al. Chemically defined generation of human cardiomyocytes. Nature methods. 11 (8), 855-860 (2014).
  14. Kleinsorge, M., Cyganek, L. Subtype-directed differentiation of human iPSCs into atrial and ventricular cardiomyocytes. STAR Protocols. , 100026 (2020).
  15. Knollmann, B. C., Katchman, A. N., Franz, M. R. Monophasic action potential recordings from intact mouse heart: validation, regional heterogeneity, and relation to refractoriness. Journal of Cardiovascular Electrophysiology. 12 (11), 1286-1294 (2001).
  16. Leopold, J. A., Loscalzo, J. Emerging role of precision medicine in cardiovascular disease. Circulation Research. 122 (9), 1302-1315 (2018).
  17. Voigt, N., Zhou, X. B., Dobrev, D. Isolation of human atrial myocytes for simultaneous measurements of Ca2+ transients and membrane currents. Journal of Visualized Experiments. (77), e50235 (2013).
  18. Voigt, N., et al. Enhanced sarcoplasmic reticulum Ca2+ Leak and increased Na+-Ca2+ exchanger function underlie delayed afterdepolarizations in patients with chronic atrial fibrillation. Circulation. 125 (17), 2059-2070 (2012).
  19. Voigt, N., et al. Cellular and molecular mechanisms of atrial arrhythmogenesis in patients with paroxysmal atrial fibrillation. Circulation. 129 (2), 145-156 (2014).
  20. Fakuade, F. E., et al. Altered atrial cytosolic calcium handling contributes to the development of postoperative atrial fibrillation. Cardiovascular Research. , 162 (2020).
  21. Gross, E., Bedlack, R. S., Loew, L. M. Dual-wavelength ratiometric fluorescence measurement of the membrane dipole potential. Biophysical Journal. 67 (1), 208-216 (1994).
  22. Matiukas, A., et al. Near-infrared voltage-sensitive fluorescent dyes optimized for optical mapping in blood-perfused myocardium. Heart Rhythm. 4 (11), 1441-1451 (2007).
  23. Mutoh, H., et al. Spectrally-resolved response properties of the three most advanced fret based fluorescent protein voltage probes. PLoS One. 4 (2), 4555 (2009).
  24. Hochbaum, D. R., et al. All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins. Nature Methods. 11 (8), 825-833 (2014).
  25. Huang, Y. L., Walker, A. S., Miller, E. W. A photostable silicon rhodamine platform for optical voltage sensing. Journal of the American Chemical Society. 137 (33), 10767-10776 (2015).
  26. Deal, P. E., Kulkarni, R. U., Al-Abdullatif, S. H., Miller, E. W. Isomerically pure tetramethylrhodamine voltage reporters. Journal of the American Chemical Society. 138 (29), 9085-9088 (2016).
  27. Fluhler, E., Burnham, V. G., Loew, L. M. Spectra, membrane binding, and potentiometric responses of new charge shift probes. Biochemistry. 24 (21), 5749-5755 (1985).
  28. Fromherz, P., Muller, C. O. Voltage-sensitive fluorescence of amphiphilic hemicyanine dyes in neuron membrane. Biochimica et Biophysica Acta. 1150 (2), 111-122 (1993).
  29. Salama, G., et al. Properties of new, long-wavelength, voltage-sensitive dyes in the heart. Journal of Membrane Biology. 208 (2), 125-140 (2005).
  30. Jin, L., et al. Single action potentials and subthreshold electrical events imaged in neurons with a fluorescent protein voltage probe. Neuron. 75 (5), 779-785 (2012).
  31. Kralj, J. M., Douglass, A. D., Hochbaum, D. R., MacLaurin, D., Cohen, A. E. Optical recording of action potentials in mammalian neurons using a microbial rhodopsin. Nature Methods. 9 (1), 90-95 (2012).
  32. Tsutsui, H., Karasawa, S., Okamura, Y., Miyawaki, A. Improving membrane voltage measurements using FRET with new fluorescent proteins. Nature Methods. 5 (8), 683-685 (2008).
  33. Lundby, A., Mutoh, H., Dimitrov, D., Akemann, W., Knöpfel, T. Engineering of a genetically encodable fluorescent voltage sensor exploiting fast Ci-VSP voltage-sensing movements. PLoS One. 3 (6), 2514 (2008).
  34. Bradley, J., Luo, R., Otis, T. S., DiGregorio, D. A. Submillisecond optical reporting of membrane potential in situ using a neuronal tracer dye. The Journal of neuroscience. 29 (29), 9197-9209 (2009).
  35. Herron, T. J., Lee, P., Jalife, J. Optical imaging of voltage and calcium in cardiac cells & tissues. Circulation Research. 110 (4), 609-623 (2012).
  36. Kappadan, V., et al. High-resolution optical measurement of cardiac restitution, contraction, and fibrillation dynamics in beating vs. blebbistatin-uncoupled isolated rabbit hearts. Frontiers in Physiology. 11, 464 (2020).
  37. Kettlewell, S., Walker, N. L., Cobbe, S. M., Burton, F. L., Smith, G. L. The electrophysiological and mechanical effects of 2,3-butane-dione monoxime and cytochalasin-D in the Langendorff perfused rabbit heart. Experimental Physiology. 89 (2), 163-172 (2004).
  38. Képiró, M., et al. para-Nitroblebbistatin, the non-cytotoxic and photostable Myosin inhibitor. Angewandte Chemie International Edition. 53 (31), 8211-8215 (2014).


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