Using a harmless virus, they introduced a gene for a light-sensitive protein into "inner retinal neurons" in a strain of mice with photoreceptor deficiency that resembles the defect in such inherited human disorders as retinitis pigmentosa. Unlike the retinal rods and cones that normally function as light-sensing cells in the eye, these retinal neurons are normally not photosensitive. The light-sensitive protein they used, called channelrhodopsin-2 (ChR2), is found in green algae.
As reported in the April 6, 2006 issue of Neuron, Zhuo-Hua Pan of Wayne State University School of Medicine and colleagues found that the introduced protein rendered the retinal neurons sensitive to light. What’s more, they found, the protein persisted for long periods in the neurons, and the neurons generated signals that were transmitted to the visual cortex of the animals’ brains.
"With this strategy, the investigators have made a paradigm shift in the field and opened the possibility of genetically modifying the surviving retinal interneurons to function as a replacement light-sensing receptor," wrote John Flannery and Kenneth Greenberg in a preview of the paper in the same issue of Neuron. "This publication is clearly a significant first step into this new field of re-engineering retinal interneurons as genetically modified ’prosthetic’ cells," they wrote.
Pan and his colleagues cautioned that far more research must be done to determine whether their genetic engineering approach can be applied to restore vision in humans with inherited retinal degeneration disorders. For one thing, they said, they have not yet determined whether the light signals reaching the visual cortex could be interpreted as vision. Also, the algal protein is less sensitive to light than is the normal light-detecting protein in the eye.
Finally, they wrote, it remains unclear which of the many inherited retinal diseases might be treatable by using the technique. "The remodeling of inner retinal neurons triggered by photoreceptor degeneration has raised some concerns for the retinal-based rescue strategy after the death of photoreceptors," wrote Pan and colleagues. "However, retinal degenerative diseases are heterogeneous as to the time course of the degeneration, survival cell types, and, possibly, their functional state. Therefore, further studies are required to evaluate what types of retinal degenerative diseases and/or what disease stages are suitable for this potential treatment strategy," they wrote.
However, noted the researchers, their technique avoids some problems presented by other approaches to restoring vision in such diseases. These approaches include transplantation of normal photoreceptor cells into the eye or implantation of electronic retinal "chips" to replace the photoreceptor function.
"An important advantage of the strategy sought in this study is that it does not involve the introduction of tissues or devices into the retina and, therefore, may largely avoid the complications of immune reactions and biocompability," wrote the researchers. "In addition, it could potentially achieve high spatial resolution for the restored ’vision’ because the approach targets the cellular level. Thus, the expression of microbial-type channelrhodopsins, such as ChR2, in surviving retinal neurons may be another potential strategy for the treatment of complete blindness caused by rod and cone degeneration," they wrote.
Heidi Hardman | EurekAlert!
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy