Biosensors 2012, 2(3), 273-290; doi:10.3390/bios2030273
Article

A Comparative Study of Impedance versus Optical Label-Free Systems Relative to Labelled Assays in a Predominantly Gi Coupled GPCR (C5aR) Signalling

Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
* Author to whom correspondence should be addressed.
Received: 30 May 2012; in revised form: 11 July 2012 / Accepted: 24 July 2012 / Published: 26 July 2012
PDF Full-text Download PDF Full-Text [871 KB, uploaded 26 July 2012 14:56 CEST]
Abstract: Profiling ligand function on G-protein coupled receptors (GPCRs) typically involves using transfected cells over-expressing a target of interest, a labelled ligand, and intracellular secondary messenger reporters. In contrast, label-free assays are sensitive enough to allow detection in native cells, which may provide a more physiologically relevant readout. Here, we compare four agonists (native agonists, a peptide full agonist and a peptide partial agonist) that stimulate the human inflammatory GPCR C5aR. The receptor was challenged when present in human monocyte-derived macrophages (HMDM) versus stably transfected human C5aR-CHO cells. Receptor activation was compared on label-free optical and impedance biosensors and contrasted with results from two traditional reporter assays. The rank order of potencies observed across label-free and pathway specific assays was similar. However, label-free read outs gave consistently lower potency values in both native and transfected cells. Relative to pathway-specific assays, these technologies measure whole-cell responses that may encompass multiple signalling events, including down-regulatory events, which may explain the potency discrepancies observed. These observations have important implications for screening compound libraries against GPCR targets and for selecting drug candidates for in vivo assays.
Keywords: GPCR; impedance and optical biosensors; label-free; secondary messenger; signal transduction

Article Statistics

Load and display the download statistics.

Citations to this Article

Cite This Article

MDPI and ACS Style

Halai, R.; Croker, D.E.; Suen, J.Y.; Fairlie, D.P.; Cooper, M.A. A Comparative Study of Impedance versus Optical Label-Free Systems Relative to Labelled Assays in a Predominantly Gi Coupled GPCR (C5aR) Signalling. Biosensors 2012, 2, 273-290.

AMA Style

Halai R, Croker DE, Suen JY, Fairlie DP, Cooper MA. A Comparative Study of Impedance versus Optical Label-Free Systems Relative to Labelled Assays in a Predominantly Gi Coupled GPCR (C5aR) Signalling. Biosensors. 2012; 2(3):273-290.

Chicago/Turabian Style

Halai, Reena; Croker, Daniel E.; Suen, Jacky Y.; Fairlie, David P.; Cooper, Matthew A. 2012. "A Comparative Study of Impedance versus Optical Label-Free Systems Relative to Labelled Assays in a Predominantly Gi Coupled GPCR (C5aR) Signalling." Biosensors 2, no. 3: 273-290.

Biosensors EISSN 2079-6374 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert