Imaging giant Olympus, the official distributor of CompuCyte's line of laser scanning cytometers outside the US, has completed its own validation of the ubiquitous Transfluor fluorescent translocation assay for GPCR screening on CompuCyte's iCyte imaging cytometer.
In the work, which was published in the March 18 online edition of Cytometry A, scientists from Olympus and Xsira Pharmaceuticals — Transfluor's former owner — developed two new image-processing algorithms to quantitatively measure the movement of arrestin-GFP translocation in genetically engineered human osteosarcoma cell lines.
"Olympus recognizes the drug development area as one of the important markets in the near future," Kazuo Ozawa, lead author on the paper and lead scientist in Olympus' Bioscience Division wrote in an e-mail to CBA News. "This paper indicates part of our R&D activities toward this target."
Ozawa wrote that Norak Biosciences — Xsira's predecessor — initiated the project with Olympus about two years ago when Norak was implementing its strategy of saturating the marketplace with Transfluor by validating it on as many high-content instrumentation platforms as possible.
"All authors of this paper are molecular biologists and we decided to publish our evaluation results to appeal the versatility of the automated imaging approach for drug development not only to drug-discovery [researchers], but also to academic researchers," Ozawa wrote.
In fact, CompuCyte itself had already validated Transfluor on the iCyte prior to the recent paper; however, the recent Olympus work has provided another set of algorithms with which to quantitatively measure GPCR activity in cells.
"The basic marketing strategy that was used by Xsira was that they practically encouraged all manufacturers of cell-based platforms to look at their technology," Elena Holden, CompuCyte's president and CEO told CBA News last week. "[CompuCyte's] validation of the GPCR assay from Norak started about two years ago, when we were approached by them. They also approached Olympus in Japan, so we started doing two individual validations, and we compared our notes with Olympus at our cytometry workshop in San Francisco last year."
In the Cytometry A paper, Ozawa and colleagues showed that an arrestin-GFP fusion protein translocates and binds to activated GPCR at the plasma membrane upon agonist stimulation. The complexes then congregate in clathrin-coated pits and intracellular vesicles. According to the study, the quantitation of these condensed fluorescent spots can be used to visually monitor the extent of GPCR activation.
"The Olympus people used our existing software, and were able to apply the existing algorithms to do the quantitation, which was shown in the paper," Ed Luther, CompuCyte's principal scientist further explained. "The one that worked the best was to just quantify the vesicles as they overlapped the nucleus. And they showed that the data correlated very nicely with the Norak data.
"We did our own studies where we had the developmental software available to us, and we were able to get the same results but to increase the throughput," Luther added. "We were able to use new software features that let us do the same type of measurements, but faster and more specifically."
Olympus' relationship with CompuCyte is comparable to that between competitors Zeiss and Cellomics. Zeiss is Cellomics' official US distributor for academic and biotechnology customers. In addition, Cellomics' flagship HCS instrument, the ArrayScan, uses Zeiss' Apotome technology to enable confocal-like imaging. Likewise, Olympus distributes for CompuCyte in certain arenas, and the CompuCyte platform is based on Olympus microscopy components.
Every additional instrumentation validation of Transfluor is a bonus to the assay technology's current owner, Molecular Devices. Even though MDCC will soon be launching a new imaging platform designed to maximize the benefits of Transfluor, the company has maintained that it will be licensing out the assay to those who wish to use it on another instrumentation platform (see related story, this issue).
Currently, the list of instruments beside the iCyte on which Transfluor has been validated include the aforementioned ArrayScan, GE Healthcare's IN Cell Analyzer 1000 and 3000; TTP LabTech's Acumen Explorer; MDCC's Discovery-1 and ImageXpress; Evotec's Opera; Beckman Coulter's Cell Lab IC 100; and BD Bioscience's Pathway HT.