Cel-gebaseerde Calcium Assay voor medium tot hoge throughput screening van TRP Channel functies met behulp van FlexStation 3
Summary
This video provides a detailed protocol for studying the pharmacological profile of human TRPA1 channels using FlexStation 3. The protocol covers details of cell preparation, dye loading and operation of the microplate reader, FlexStation 3.
Abstract
The Molecular Devices’ FlexStation 3 is a benchtop multi-mode microplate reader capable of automated fluorescence measurement in multi-well plates. It is ideal for medium- to high-throughput screens in academic settings. It has an integrated fluid transfer module equipped with a multi-channel pipetter and the machine reads one column at a time to monitor fluorescence changes of a variety of fluorescent reagents. For example, FlexStation 3 has been used to study the function of Ca2+-permeable ion channels and G-protein coupled receptors by measuring the changes of intracellular free Ca2+ levels. Transient receptor potential (TRP) channels are a large family of nonselective cation channels that play important roles in many physiological and pathophysiological functions. Most of the TRP channels are calcium permeable and induce calcium influx upon activation. In this video, we demonstrate the application of FlexStation 3 to study the pharmacological profile of the TRPA1 channel, a molecular sensor for numerous noxious stimuli. HEK293 cells transiently or stably expressing human TRPA1 channels, grown in 96-well plates, are loaded with a Ca2+-sensitive fluorescent dye, Fluo-4, and real-time fluorescence changes in these cells are measured before and during the application of a TRPA1 agonist using the FLEX mode of the FlexStation 3. The effect of a putative TRPA1 antagonist was also examined. Data are transferred from the SoftMax Pro software to construct concentration-response relationships of TRPA1 activators and inhibitors.
Protocol
Discussion
Intracellular Ca2+ plays important roles in many physiological and pathological conditions, such as neurotransmitter release (3), cardiac action potential (4), muscle cell contraction (5), cell signal transduction (6-7), and excitotoxic cell death (8). Measurement of intracellular Ca2+ levels helps to elucidate functional changes of Ca2+-permeable channels in the plasma membrane or intracellular organelles and the contribution of
Ca2+ to the above processes (9-13). The as…
Disclosures
The authors have nothing to disclose.
Acknowledgements
We thank Drs. John Hancock, Ray Grill, Andrew Morris and Olga Chumakova for their support. The FlexStation 3 system is part of the UTHSC Cytodynamic Imaging Facility. We also thank Drs. Ardem Patapoutian and Michael Bandell from the Scripps Research Institute and Genomics Institute of the Novartis Research Foundation (GNF) for providing the HEK293-hTRPA1 stable cell line. The research is supported in part by grants from NIH (GM081658 to MXZ) and Texas Medical Center Digestive Diseases Center (to HH) and Mission Connect/TIRR Foundation (to HH).
Materials
| Name of the reagent | Company | Catalogue number | Comments (optional) |
|---|---|---|---|
| FlexStation 3 | Molecular Devices | FLEX3 | |
| 96-Well, FlexStation Pipet Tips | Molecular Devices | 9000-0912 | |
| 96-Well Plates | Greiner Bio-one | 655090 | |
| 96-Well Clear Flat Bottom plates | Costar | 3595 | |
| DMEM | Invitrogen | 12430-104 | |
| Opti-MEM | Invitrogen | 31985-070 | |
| Lipofectamine 2000 | Invitrogen | 11668-019 | |
| Fluo-4 AM | Invitrogen | F14202 | |
| PluronicF-127 | Invitrogen | P3000MP | |
| Poly-L-ornithine | Sigma | P36551 | |
| probenecid | Sigma | P8761 | |
| Bovine serum albumin | Sigma | A9418 |
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