from the dreams-of-modern-medicine dept.
An upcoming human trial will attempt to use optogenetics to treat conditions such as retinitis pigmentosa:
In the next month, scientists from RetroSense Therapeutics will inject a virus deep into the retina of legally blind human volunteers. The virus will carry what is perhaps the most monumental payload in modern neuroscience history: DNA that codes for channelrhodopsin-2, a light-responsive protein isolated from algae that — under blue light — activates cells in the retina, thereby transmitting visual information to the brain.
Forget electronic implants. If all goes well, these volunteers will be able to see again using their own eyes — but in no way a human being has ever experienced sight before. Whoa.
But the stakes are even higher: if this works, it means that optogenetics — a revolutionary neuroscience technique using channelrhodopsin-2 and other light-activated proteins — is feasible in humans as therapy. Considering optogenetics has been used in mice to implant false memories, treat cocaine addiction, attenuate OCD symptoms, trigger sexual advances and aggression and reverse motor deficits in Parkinson's disease — just to name a few feats— the technique could completely transform the face of neurology. "This is going to be a gold mine of information about doing optogenetics studies in humans," said Dr. Antonello Bonci, the scientific director of the intramural research program at the National Institute on Drug Abuse, to MIT Technology Review.
[...] If it works, what will the patients see? No one can say for sure. After all, this will be the first time humans experience the visual world through the light sensor of algae. But studies with blind lab mice may give us a hint. In one previous study, after optogenetics treatment, previously blind mice could swim out of a chamber in which the escape route was brightly lit. On average, they escaped as fast as mice with normal vision.
Researchers have created a protein that breaks into two pieces when exposed to light:
Researchers at the University of Alberta have developed a new method of controlling biology at the cellular level using light. The tool -- called a photocleavable protein -- breaks into two pieces when exposed to light, allowing scientists to study and manipulate activity inside cells in new and different ways.
First, scientists use the photocleavable protein to link cellular proteins to inhibitors, preventing the cellular proteins from performing their usual function. This process is known as caging. "By shining light into the cell, we can cause the photocleavable protein to break, removing the inhibitor and uncaging the protein within the cell," said lead author Robert Campbell, professor in the Department of Chemistry. Once the protein is uncaged, it can start to perform its normal function inside the cell. The tool is relatively easy to use and widely applicable for other research that involves controlling processes inside a cell.
Optogenetic control with a photocleavable protein, PhoCl (DOI: 10.1038/nmeth.4222) (DX)
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