Curing blindness, with light-activated ion channels?
How would you cure blindness, if your phototransducing rods and cones had degenerated – as happens in syndromes that affect millions of people worldwide? A lot of investigators have tried to create very complicated electrical stimulators that drive patterned activity in the retina. You need a power source, a camera of sorts, a computational element, and an array of electrodes that can crank out precise, well-timed current pulses, for a long time. It’s a heroic piece of optical and electrical engineering.
But what if you just made other cells in the retina light-sensitive? Channelrhodopsin and other light-activated ion channels have opened up this new kind of endeavor.
Investigators at Wayne State University, the Pennsylvania College of Optometry, and Beijing University have now done this. They expressed Channelrhodopsin in retinal ganglion cells (RGCs) of mice with photoreceptor degeneration. Remarkably, for months afterwards, the RGCs were able to transmit visual information all the way to visual cortex. In mice without channelrhodopsin, these visual evoked responses were never seen. A very impressive piece of systems bioengineering.
Ectopic Expression of a Microbial-Type Rhodopsin Restores Visual Responses in Mice with Photoreceptor Degeneration
Anding Bi, Jinjuan Cui, Yu-Ping Ma, Elena Olshevskaya, Mingliang Pu, Alexander M. Dizhoor, and Zhuo-Hua Pan
— Ed
April 6th, 2006 at 10:37 pm
Hey Neurodudes, it looks like we’ve made Slashdot. Man, channelrhodopsin is so hot!
April 8th, 2006 at 12:25 pm
[...] Update: There is a brief post, made over at the neurodudes blog, on curing blindness in mice through light activated ion channels. [...]
April 11th, 2006 at 1:56 am
The paper shows that channelrhodopsin is essentially safe forever. This could lead to optical prosthetics in a broader sense, driving neurons in the brain that have been infected with AAV or some other fairly safe virus.
April 14th, 2006 at 5:56 pm
Nice research catch. Keep it up.
April 16th, 2006 at 12:14 pm
For congenital disorders, waiting until the child grows up may corrupt cortex… maybe in utero electroporation, or some well-timed gene delivery, would be a good way to go?
April 16th, 2006 at 4:10 pm
in utero electroporation! wouldn’t that be dangerous to the embryo?
I don’t know much about the technique, but the abstract of this article says the embryo survival rate was 90%. I expect that other 10% would generate a lot of controversy, but I also wonder if it’s possible for the technique to hurt the embryo without killing it, leading to problems down the line.