A new electro-optical approach for conductance measurement: an assay for the study of drugs acting on ligand-gated ion channels.
Ligand gated ion channels are involved in many pathophysiological processes and represent a relevant, although challenging, target for drug discovery. We propose an innovative electro-optical approach to their analysis able to derive membrane conductance values from the local membrane potential changes imposed by test current pulses and measured by fast voltage-sensitive fluorescent dyes. We exploited the potential of this proprietary method by developing a drug testing system called "ionChannel Optical High-content Microscope" (ionChannelΩ). This automated platform was validated by testing the responses of reference drugs on cells expressing different ligand-gated ion channels. Furthermore, a double-blind comparison with FLIPR and automated patch-clamp was performed on molecules designed to act as antagonists of the P2RX7 receptor. ionChannelΩ proved highly reliable in all tests, resulting faster and more cost-effective than electrophysiological techniques. Overall, ionChannelΩ is amenable to the study of ligand gated ion channels that are receiving less attention due to limitations in current assays.
San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.|San Raffaele University, via Olgettina 58, 20132, Milan, Italy.
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Menegon
Optotec, Via Zenale 44, 20024, Garbagnate Milanese, Milan, Italy.
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Pitassi
San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
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Mazzocchi
Axxam SpA, via Meucci 3, 20091, Bresso, Milan, Italy.
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Redaelli
Axxam SpA, via Meucci 3, 20091, Bresso, Milan, Italy.
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Rizzetto
Axxam SpA, via Meucci 3, 20091, Bresso, Milan, Italy.
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Rolland
Valore Qualità, Via Vidari 5, 27100, Pavia, Italy.|Assing, Pavia, Viale Indipendenza 11, I-27100, Pavia, Italy.
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Poli
OPEN Sistemi, via Bonomelli 24, 26100, Cremona, Italy.
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Imberti
Valore Qualità, Via Vidari 5, 27100, Pavia, Italy.|Assing, Pavia, Viale Indipendenza 11, I-27100, Pavia, Italy.
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Lanati
San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.|San Raffaele University, via Olgettina 58, 20132, Milan, Italy.
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Grohovaz
D057205:Automation, Laboratory; D002463:Cell Membrane Permeability / Q000187:drug effects; D055808:Drug Discovery / Q000379:methods*; D057166:High-Throughput Screening Assays; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects*; D058446:Ligand-Gated Ion Channels / Q000378:metabolism*; D008024:Ligands; D008564:Membrane Potentials / Q000187:drug effects; D008853:Microscopy / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods; D061848:Optical Imaging / Q000379:methods*; D015203:Reproducibility of Results
D058446:Ligand-Gated Ion Channels; D008024:Ligands