A novel method for analyzing [Ca2+] flux kinetics in high-throughput screening

Driven by multiparameter fluorescence readouts and the analysis of kinetic responses from biological assay systems, the amount and complexity of high-throughput screening data are constantly increasing. As a consequence, the reduction of data to a simple number, reflecting a percentage activity/inhibition, is no longer an adequate approach because valuable additional information, for example, about compound- or process-induced artifacts, is lost. Time series data such as the transient calcium flux observed after activation of Gq-coupled G protein-coupled receptors (GPCRs), are especially challenging with respect to quantity of data; typically, responses are followed for several minutes. Based on measurements taken on the fluorometric imaging plate reader, the authors have introduced a mathematical model to describe the time traces of cellular calcium fluxes mediated by the activation of GPCRs. The model describes the time series using 13 parameters, reducing the amount of data by 90% while guiding the detection of compound-induced artifacts as well as the selection of compounds for further characterization.