New red fluorescent probe for lysosome studies

Researchers from Enzo Life Sciences in Farmingdale, NY have been developing a new red fluorescence molecular probe for detecting phospholipidosis occurring in lysosomes.

Phospholipidosis -- tiny bubbles occurring in a lysosome -- sometimes happens in response to certain drugs. Although drugs that cause this process are not taken off the market, the FDA is seeking more information on the process. Also, if during drug screening a compound is found to cause phospholipidosis, it is usually not pursued further.

With the increasing interest in the process of phospholipidosis, it is important to have a way to detect the process accurately and with minimal work and time. Other fluorescent probes such as Acridine Orange and Lysotracker Red can detect changes in lysosomes, but they can’t be used with GFP and other fluorescent proteins. In addition, these fluorescent probes are more suitable for static identification, rather than dynamic tracking of processes.

The probe they developed, called Lyso-ID, has a 660-nm (red) emission that makes it usable with GFP-expressing cell lines (as well as lines expressing other fluorescent proteins). It can be used with microscopes, flow cytometers and with microplate readers. In addition, it is photostable, doesn’t photoconvert, and requires less time and processing steps than competing probes.

To test the probe, they used it to scan a library of 480 compounds to see which ones would cause phospholipidosis using a microplate reader. They were able to successfully identify compounds known to cause this process.