Scientists at the University of Groningen and the University Medical Center Groningen used molecular motors to manipulate the protein matrix on which bone marrow-derived mesenchymal stem cells are grown. Rotating motors altered the protein structure, which resulted in a bias of the stem cells to differentiate into bone cells (osteoblasts). Without rotation, the stem cells tended to remain multipotent. These results, which could be used in tissue engineering, were published in Science Advances on 29 January.
'Cells are sensitive to the structure of the surface that they attach to,' explains Patrick van Rijn, associate professor in Materiobiology and Nanobiomaterials. 'And movement is an important driver in biology, especially continuous movement.'
The movement of motor molecules interferes with the alpha-helices in the proteins, which causes structural changes. The change in the structure of the protein affects how the cells attach. This sets off a signaling cascade that eventually leads to altered behavior, such as the differentiation into bone cells. Thus, molecular movement leads to nanoscopic changes in surface structure, which in turn leads to differences in cell attachment, cell morphology and eventually, cell differentiation.
Credit: Zhou et al, University of Groningen
That is why Van Rijn and Feringa and their colleagues decided to use molecular motors to manipulate the protein matrix on which stem cells are grown. The light-driven motor molecules were designed by the 2016 Nobel Laureate in Chemistry Ben Feringa.
The scientists linked molecular motors to a glass surface. Subsequently, the surface was coated with protein and either exposed to UV irradiation to power the motors or not exposed to it at all. After about an hour, the motor movement was stopped and cells were seeded onto the protein layer and left to attach.
Finally, differentiation factors were added. These experiments showed that cells grown on protein that was submitted to the rotary motion of the molecular motors tended to specialize into bone cells more often, while cells seeded on protein that was not disturbed were more inclined to maintain their stem-cell properties.
Observations of the protein layer using atomic force microscopy and simulations of the interaction between the motor molecules and proteins, performed by Prof. Marrink's research group, showed that the movement induced subtle structural changes in the protein matrix.
'The movement of motor molecules interferes with the alpha-helices in the proteins, which causes structural changes,' explains Van Rijn. He compares it to the difference in texture between an unwhipped egg white and a whipped one.
The change in the surface structure of the adhered protein affects how the cells attach, for example how much they stretch out. This sets off a signaling cascade that eventually leads to altered behavior, such as the differentiation into bone cells.
Thus, molecular movement leads to nanoscopic changes in surface structure, which in turn leads to differences in cell attachment, cell morphology and eventually, cell differentiation. 'It's like a domino effect, where smaller stones consecutively topple slightly larger ones so that a large effect can be achieved with a small trigger.'
'Changing the properties of a surface to affect cell fate has been used before,' says Van Rijn. However, this was done primarily with switches, so there was just a change from one state to another. 'In our study, we had continuous movement, which is much more in line with the continuous motion found in biological transport and communication systems.
The fact that the motors are driven by light is important,' Van Rijn adds. 'Light can be carefully controlled in space and time. This would allow us to create complex geometries in the growth matrix, which then result in different properties for the cells.' Therefore, light-controlled molecular motors could be a useful tool in tissue engineering.
Simple Science Summary
The surface on which cells are grown can affect their properties. Scientists have used molecular motors, which rotate when irradiated with light, to change the structure of a protein layer on which stem cells were seeded. These stem cells, derived from bone marrow, can form different cell types or they can remain stem cells. The movement of the motors primed the stem cells to transform more efficiently into bone cells. This technique could be used to dynamically control cellular behavior on surfaces and create complex cell layers and tissues with different cell types by changing the properties of the protein layer at specific places.
Reference: Qihui Zhou, Jiawen Chen, Yafei Luan, Petteri A. Vainikka, Sebastian Thallmair, Siewert J. Marrink, Ben L. Feringa, Patrick van Rijn: Unidirectional rotating molecular motors dynamically interact with adsorbed proteins to direct the fate of mesenchymal stem cells. Science Advances, 29 January 2020.
Rene Fransen | EurekAlert!
Superresolution live-cell imaging provides unexpected insights into the dynamic structure of mitochondria
18.02.2020 | Heinrich-Heine-Universität Düsseldorf
Blood and sweat: Wearable medical sensors will get major sensitivity boost
18.02.2020 | Moscow Institute of Physics and Technology
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices
The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...
Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.
Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.
After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.
"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.
Superconductivity approaching room temperature may be possible in hydrogen-rich compounds at much lower pressures than previously expected
Reaching room-temperature superconductivity is one of the biggest dreams in physics. Its discovery would bring a technological revolution by providing...
12.02.2020 | Event News
16.01.2020 | Event News
15.01.2020 | Event News
18.02.2020 | Life Sciences
18.02.2020 | Earth Sciences
18.02.2020 | Life Sciences