Kenneth B. Walsh
University of Rochester, School of Medicine
Ph.D: University of Cincinnati, College of Medicine
Cell-based screening assays are now commonly used in ion channel drug discovery. The typical approach to identifying new ion channel modulators has involved the expression of recombinant channels in heterologous cell lines such HEK-293 and CHO cells. However, these cells often lack the relevant “physiological environment” that is present in native tissues, and required for normal pharmacological responses. Thus, my laboratory is examining the suitability of primary cells, and clonal cell lines derived from animal tissues, for cell-based drug discovery using fluorescent indicators.
In one project, immortalized cardiac and neuronal cell lines are used for identifying blockers of G protein-coupled inward rectifier K+ (GIRK) channels. Cells are plated in 96-well plates, loaded with a membrane potential-sensitive fluorescent dye, and GIRK channels activated with drugs or hormones. Fluorescent signals are then measured using a fluorescent imaging plate reader (FLIPR).
In the photos on the right, Ca2+ fluorescent images measured in cardiac cells before (top image) and after stimulation of the angiotensin II type I receptor (bottom image).
- Walsh KB, Rich TC, Coffman ZJ. Development of a high-throughput assay for monitoring cAMP levels in cardiac ventricular myocytes. Journal of Cardiovascular Pharmacology 2009; 53:223-230.
- Walsh KB. Real time screening of GIRK1/4 channel blockers. Journal of Biomolecular Screening 2010; 15:1229-1237.
- Walsh KB. Targeting GIRK channels for the development of new therapeutic agents. Frontiers in Pharmacology 2011; 2:64.