Optogenetics—the use of light to control genetically modified neurons—has rapidly become one of the hottest fields in neuroscience. Optogenetic technology is now in use in hundreds of labs across the globe, helping scientists gain insight into the brain. While the bulk of the research is focused in basic science, a handful of projects published this year point the way toward clinical applications. Researchers at Weill Cornell Medical College, in New York, developed a more accurate prosthetic retina for blind mice that had been genetically engineered to express a light-sensitive protein in certain retinal cells. (Now I See You) Gene therapy might one day make the same possible for humans.
Karl Deisseroth and colleagues at Stanford used optogenetic technology to control muscle movement in mice genetically engineered to express a light-sensitive protein in their peripheral nervous system. A tiny implantable LED cuff delivered millisecond pulses of light to the nerve, causing the animals’ leg muscles to contract. The researchers say that the light-triggered contractions mimicked normal muscle activity more closely than contractions generated by delivering electrical signals directly to the nerve. (Genetic ‘Light Switches’ Control Muscle Movement) The findings could aid in the development of nerve-stimulator devices that will help people paralyzed from spinal-cord injuries or disease.
To use optogenetics in the human brain, researchers need to figure out how to deliver light deep in the brain. Medtronic, one of the world’s largest medical-device makers, is working on just that. The company currently makes electrical deep-brain stimulators, which are approved to treat Parkinson’s and other neurological disorders. A similar device that delivers light rather than electricity could help improve the design of deep-brain stimulators, and might eventually become a therapy itself. (A Brain Implant that Uses Light)
Ed Boyden, one of the creators of the optogenetics, was featured in the October issue of Technology Review (Brain Control) and in a guest column online writes more about how science is co-opting nature’s ingenious solutions. (Defining an Algorithm for Inventing from Nature)
Finally, Craig Venter and colleagues at the Venter Institute created life. (Synthetic Genome Reboots Cell, Making a Genome Quickly from Scratch) In the culmination of a 15-year project, researchers created a synthetic genome and then used it to reboot a microbial cell.
Using a method developed in 2008, the researchers, led by genomics pioneer Craig Venter, synthesized the genome of a tiny bacterium called Mycoplasma mycoides, containing just over a million DNA base pairs. Next they transplanted the synthetic genome into a related bacterium, Mycoplasma capricolum, in a process they had previously perfected using nonsynthetic chromosomes.
Once the recipient cells incorporated the synthetic genome, they immediately began to carry out the instructions encoded within the genome. The cells manufactured only M. mycoides proteins, and within a few rounds of self-replication, all traces of the recipient species were gone.
Venter and his colleagues are now working with Novartis and the National Institutes of Health to adapt the technology to quickly create vaccines against new strains of the flu virus.