Mathieu Coppey imagines using tiny magnets to move cells within living organisms. Coppey, a researcher at the Institut Curie in Paris, isn't envisioning a modern day version of "magnet therapy" touted a century ago by quack medical practitioners. Instead Coppey is using nanoparticle-size magnets to manipulate processes in cells.
Coppey and colleagues were able to deploy "nano-magnets," super-paramagnetic nanoparticles coated with signaling proteins within cells. The researchers then used a larger magnet outside the cell to localize the nano-magnets to specific subcellular locations and observe the effects.
The coated nano-magnets were able to function as signaling platforms, with effects specific to the location of the magnet. For example, one protein they attached to the nano-magnets (GEF TIAM1) was able to activate downstream proteins at the plasma membrane. However, when they brought that same protein-coated nano-magnet to the leading edge of migrating cells, it promoted signaling that led to the formation of actin scaffolds near the magnet. It's possible that these actin scaffolds would promote cell motility. This research was published in Nature Nanotechnology1 in March, and presented in New Orleans at the 2013 ASCB Annual Meeting.
Interviewed in New Orleans, Coppey said that the work demonstrated that "the signal transduction is really compartmentalized in the cell." According to Coppey, "We expected that the signal would spread but everything that we activated stayed local... that was a big surprise."
While optogenetics is being touted as the hot new tool to modulate cell signaling by switching protein interactions on and off using light, Coppey believes that his nano-magnets have some advantages over optogenetic switches. "You know exactly how many proteins you have on the particles and you can have just one spot of signaling," he said.
During his postdoc in Stanislav Shvartsman's lab at Princeton, Coppey worked on morphogenesis, the process by which organisms take shape. "I realized that all of that was really a matter of signal transduction organized in space and time, and I wanted to have more advanced tools to look at that." That's how he got started with nano-magnets.
Coppey's research is currently focused on signal transduction that is specifically organized in the cell, like cell polarity or cell motility. "In the future we would like to be able to control the motility of cells within tissues... optogenetics works for tissues that are transparent, but the magnets could work in a big tissue," he said.
1Etoc F, Lisse D, Bellaiche Y, Piehler J, Coppey M, Dahan M (2013). Subcellular control of Rac-GTPase signalling by magnetogenetic manipulation inside living cells. Nat Nanotechnol.193-8. doi: 10.1038