EMBL researchers use optogenetics to drive structure changes in tissues
In optogenetics, researchers use light to control protein activity. This technique allows them to alter the shape of embryonic tissue and to inhibit the development of abnormalities.
Now, scientists in EMBL's De Renzis group have enhanced the technique to stop organ-shaping processes in fruit fly embryos. Their results, published in The EMBO Journal, allow control over a crucial step in embryonic development.
For healthy development, tissue has to change its shape. For example, groups of cells alter their shape as part of the development of organs. Stefano De Renzis and his team members at EMBL are interested in the mechanisms behind these shape transitions and use optogenetics to steer them with light.
Video 1: Side view of invagination process. The outer/apical surface of the cells contracts, while the inner/basal surface relaxes. This coordinated process generates a force that drives the cell towards the inside of the embryo. This is the first step towards the development of an organ. IMAGE: Daniel Krüger / EMBL
To form internal organs like kidneys, groups of cells must move towards the inside of an embryo. During this process, called invagination, the surface of a group of cells contracts and causes the tissue to fold inwards. "Imagine the embryo as a balloon and tissue invagination as the deformation caused by fingers that push the surface of the balloon inwards. The only difference is that cells are not being subjected to an external force like the fingers, but need to be able to generate forces to move inside by themselves," says De Renzis, who led the project. Abnormalities in this process lead to problems in tissue and organ development.
Initiating and inhibiting invagination
De Renzis and his group inhibit the naturally occurring invagination process to understand its driving factors. A crucial aspect is the flexibility of the part of the tissue's surface that folds inwards. When the scientists use optogenetics to stiffen this surface, it becomes impossible for cells to bend inwards, stopping the whole invagination process. "If cells are not allowed to relax their bases, they cannot constrict their apices efficiently, and tissue invagination stops. To stick with the balloon analogy, it's like when you squeeze the top and the bottom of a balloon simultaneously. The inner pressure becomes higher and the balloon can't fold inwards anymore," says De Renzis. With their new method, it is not only possible to stop invagination before it happens, but also to stop it mid-process.
Video 2: Top view of modified and natural invagination. While the left tissue is modified with optogenetics and does not invaginate, the right tissue folds towards the embryo's inside and creates a pouch. IMAGE: Daniel Krüger / EMBL
While scientists had speculated about the importance of the tissue's basal (inner) surface before, experimental techniques were not advanced enough to test this. With their new method, the EMBL team can modify protein activity without damaging the cells, while still being able to activate and deactivate the modifications as necessary. Their results provide the first proof for a long-standing theory that could explain morphological abnormalities during embryonic development.
Combined with their previous results, the scientists are now able to control every step of this important developmental process in embryos. Although the experiments were done in fruit fly embryos, De Renzis expects the results and methods to be applicable in other organisms. Optogenetics could be used to create and shape artificial tissues or to control tissue development in regenerative medicine.
Iris Kruijen | EurekAlert!
Mass spectrometry sheds new light on thallium poisoning cold case
14.12.2018 | University of Maryland
Protein involved in nematode stress response identified
14.12.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy