Gene-encoded mouse cells are controlled by light

Experts at the University of California in San Francisco have made gene-encoded cells in mice react to light, producing cells that obey the signal of a light or stop at the command, like like tiny robots.

This is the first time researchers have been able to bring the on-off control light from plants to a mammalian cell to control different cell functions. From there, they have an effective new tool in cancer and cardiovascular research, as well as the ability to fundamentally control complex processes such as the development of nerves.

The results appear in the September 13 online edition of the journal Nature. Details are also presented along with a similar study conducted by Dr. Klaus Hahn - University of North Carolina lecturer at Chapel Hill.

These two works are the first to demonstrate that light control technology can be applied to mammalian cells to control complex processes . The authors said the study by the University of California at San

Francisco is unique in developing a 'switch', based on taking more proteins, controlling processes that change in many types of cells and organs.

Dr. Wendell Lim, one of the three senior authors of the presentation, said that the results could bring a lot of therapeutic applications, such as the ability to guide nerve cells to reconnect vertically. follow the spine broken in the spinal cord injury.

More recently, research results also provide a new approach to studying regulatory processes related to cancer and inflammation, he said.

Lim, a lecturer in the Department of Cellular and Molecular Pharmacology at the University of California in San Francisco, said: 'This is an effective tool for cancer and cell biology research. If you have a switch that can be applied to different cell functions, then with a simple light ray, you will be able to control when and where a cell is allowed to move, and What is then allowed to do when it has arrived at a specific location. '

Lim explained that many cellular processes are governed by when and where proteins appear inside cells. When these processes are based on a complex signaling system, for example in diseases such as cancer, such an on-off switch is useful.

The figure above shows three different times of an experiment, in which a red laser focuses on the periphery of a fibroblast, causing the cell to grow outward, towards the illuminated spot. via phytochrome remote control system. The position of the laser is moved slowly outward when the protruding point exceeds the 30 micrometer outer surface limit from the cell body. (Photo: © University of California in San Francisco)

The study was conducted by Anselm Levskaya, a graduate student working for both Lim's lab and the laboratory of Dr. Chris Voigt, a synthetic biologist, a professor of pharmacy chemistry at the University of California School of Pharmacy at San Francisco, who is also one of the three senior authors of the presentation.

Levskaya initially searched for plant proteins capable of acting as light-sensitive particles.It has been known that plants are heavily dependent on phytochromes - light - sensitive signaling proteins - in controlling many different processes, such as the development towards the sun or the germination of seed.

He proposed that phytochromes could be placed into mammalian cells by genetic tools and attached to a specific function that in this case is cell movement.

Levskaya found a pair of interacting proteins in plants, called PhyB-PIF interactions, that could be turned on and off like a switch , and thereby brought this signaling system into cells. The affected cell can be pulled by a light red light outside, or pushed by an external infrared ray.

'We can use similar light-sensitive elements to program bacteria and yeast cells to follow a series of pre-ordered commands,' Voigt said. 'It is worth noting here is the ability to do this in mammalian cells, and find a way to turn them off after they have completed the function that humans choose.'

Voigt said that the opposite of Levskaya's work is very meaningful. While many methods only focus on breaking down cell lines, most are quite simple and only work in one direction: they end a process, preventing two proteins from interacting, but they only doing such a convenient way. In contrast, this approach allows researchers to control exactly when the effect takes place, how long it takes, and then stop at our own will.

The work recognizes the collaboration between three California University labs in San Francisco: Voigt's laboratory with the use of synthetic biology to create light switches and light-sensitive particles in bacteria; Lim's lab has been investigating how complex signaling protein systems can make cells move, grow and separate; Laboratory of Dr. Orion Weiner as a researcher of cell movement.

All three laboratories are affiliated with the Nano Medical Research Center of the National Health Research Institute at the University of California, San Francisco. The goal of this center is to build intelligent programmed cells to conduct new therapeutic functions in cancer medicine and recovery. The above laboratories are also affiliated with the California Quantitative Biological Institute (QB3) located at the University of California, San Francisco.