A good assay, they say, is the stuff of good science. Whether it’s a whole new type of test, a twist or a tweak of an old one, or a way of combining things that hasn’t been worked out before, assay development remains an integral—if sometimes behind-the-scenes and underappreciated—part of the discovery process.
Just ask participants of the Assay Development and Screening track of the recent “SLAS 2012” conference. Researchers there discussed the challenges of solubilizing fatty acids while avoiding toxicity, and ways to optimize conditions for high-throughput screens of libraries of molecular inhibitions to generate more reliable hit lists.
Some told of ways to circumvent or directly challenge the idea that some targets may be “undruggable”, while another spoke of uncovering previously unseen mechanisms of action by eliminating an inhibitor built into the standard assay.
Lawrence Wiater, Ph.D., is working on cell-based assays to systematically investigate and characterize metabolism of fatty acids in mammalian cells. Biolog, for which he is a senior scientist and group leader, currently offers a series of 96-well microplates (Phenotype MicroArrays™) that look at metabolic effects of carbon and nitrogen substrates, ions, hormones, metabolic effectors, and anticancer agents. The fatty acid metabolism assays, which are currently in beta testing, will be an extension of that platform.
The assays can help researchers understand what pathways cells use to metabolize substrates that are in the wells, to look at the effects substrates have on cell growth, or to see if they can increase the productivity of a metabolic product in bioprocessing.
“You can just add your cells to hundreds of wells and then you can kinetically monitor each well for increased or decreased productivity of your favorite molecule,” Dr. Wiater pointed out. “You typically don’t know what may affect your pathway of interest. These microplates allow you to screen hundreds of nutritional factors that could modulate that productivity.”
Disease research, too, can benefit from the company’s Phenotype MicroArrays. “Energy metabolism is linked to obesity, diabetes, nutrition, aging, mitochondrial diseases, drug toxicities—especially those that target mitochondria—and then cancer and cachexia,” he said. “Our fatty acid microplates offer additional pathways you can probe to look for relevance in any of these health problems.”
Biolog’s OmniLog™ instrument incubates the microplates at 37°C while it reads and records the linear reduction of a tetrazolium dye to a colored formazan, thereby measuring the rate of metabolism in each well. Currently techniques such as mass spectrometry and liquid chromatography can generate a snapshot of metabolic pathways pools, but Dr. Wiater “doesn’t know of any other technology platform that can measure metabolic rates of fatty acids and other cell energy sources.”