Waking up our regenerative pathways
SIROCCO Remote control of cellular signalling triggered by magnetic switching Project Objectives
Many cells in the body respond to mechanical stimuli by activating different types of signalling pathways, which then affects cell behaviour. We spoke to Dr Moros about the work of the Sirocco project in developing functionalised magnetic nanoparticles to manipulate these pathways, which could open up the possibility of enhancing wound healing and directing stem cell fate. Many of the
cells in our body sense mechanical stimuli, which they then respond to in different ways, for example by proliferating or differentiating. In order to maintain correct blood pressure endothelial cells sense the current situation and then respond accordingly. “When they sense pressure on the surface of the cells, they respond by activating different pathways. They may need to change the contraction or relaxation of cells, finally increasing or decreasing the arterial diameter,” explains Dr María Moros, Principal Investigator of the Sirocco project. A deeper understanding of how cells convert these mechanical stimuli into biochemical activity – a process called mechanotransduction – could open up interesting new therapeutic avenues, a topic that Dr Moros is investigating in the Sirocco project. “In the project we’re looking at wound healing on the skin, which is a relatively simple model,” she says. “If it works, we can then look at other structures, like the heart, liver and intestine.” This could represent a way to essentially activate regeneration pathways which have become dormant in humans over the course of evolutionary history. Some invertebrates are able to fully regenerate themselves, such as the fresh water Hydra vulgaris, but humans do not have the same capacity. “It is not that we don’t have these regenerative pathways, it’s more like they are asleep or are only activated on very specific occasions. These pathways are really active in some of our organs like the intestine – but in other tissues, they are nearly inactive,” says Dr Moros. The wider aim in the project is to provide researchers with a tool to study these pathways and to activate them artificially, which could in the long-term open up the possibility of controlling them in a spatiotemporal way and applying them in regenerative medicine. “These pathways are really powerful in regeneration,” outlines Dr Moros.
Magnetic nanoparticles A specific regeneration pathway which is known to ultimately lead to cell division has been chosen in the project, with researchers now looking to investigate how stimuli are
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Fluorescence microscopy image showing magnetic particles (in red) attached to MDCK cells membranes expressing E-cadherin (in green). Nuclei are stained in blue.
SIROCCO Overview
Above image - TEM MNPs: Transmission Electron Microscopy Image of magnetic nanoparticles synthesized for the project.
It is not that we don’t have these regenerative pathways, it’s more like they are “asleep”. We want to be able to activate these pathways when and where we want, so we can get this spatio-temporal control that is difficult to achieve in vivo with other techniques. turned into biochemical signals, using in vitro models of the skin. It’s important to tightly control this process and avoid excessive cell division and protect other areas of the body. “We aim to strike the right balance. We need to activate this pathway, but only when we want and where we want,” stresses Dr Moros. Researchers are investigating how to specifically activate this pathway using magnetic nanoparticles, which Dr Moros says represents a highly novel approach. “We are using magnetic nanoparticles, which can be
SIROCCO will use magnetic switchers to provide a powerful magnetomechanical transduction tool for studying mechanotransduction. To this aim, magnetic nanoparticles with high magnetic moments will be functionalized with engineered fragments of cadherins. SIROCCO aims to control, with high precision and spatio temporal control, different pathways related with mechanotransduction in order to enhance wound healing and to modulate stem cell fate.
activated by stimulating them. So even if the nanoparticles go to other parts of the body, the effect will be localised,” she outlines. “We will be able to activate these pathways when and where we want, so we can get this spatiotemporal control that is difficult to achieve with other techniques.” The magnetic nanoparticles are modified with fragments of cadherins, proteins found on the surface of cells which are responsible for attachment to other cells. The nature of the cadherins depends on the type of cell. “For
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instance E-cadherins will be located mainly on epithelial cells. We have chosen this target to functionalise our nanoparticles to obtain a more specific binding,” explains Dr Moros. A nanoparticle functionalised using engineered fragments of cadherins will then attach to a cell through the cadherins on its surface, after which Dr Moros and her colleagues will apply a magnet. “The nanoparticle will be pulled or stimulated by the magnet. With this force, the cell will think that there is a certain level of pressure, and then it will activate this signalling pathway, leading to cellular proliferation,” she says. “This will occur only in cells and in the area where we have stimulated these nanoparticles with the magnet, avoiding adverse effects.” These nanoparticles need to be extremely small to specifically target the cadherins, but they must also have sufficient magnetization to be attracted to a magnet, which represents a significant challenge in research. Instead of just iron oxide, Dr Moros is looking at using other materials such as ferrites doped with manganese that are known to have high magnetic potential. “We are doing a lot of work on designing the nanoparticles and the magnets to stimulate them,” she says. A lot of attention is currently focused on making sure that the cadherins on the nanoparticle are oriented correctly, as otherwise they would not be able to interact with the cellular cadherins. The project is primarily a proof-of-concept, with researchers aiming to demonstrate that these technologies can be applied not only to wound healing, but also to directing stem cell fate. “We want to develop this technology, which is comprised of the magnetic nanoparticles attached to the cadherins, and also the magnets,” continues Dr Moros. “The technology is part of a new area of research, called magnetogenetics. We want to be confident that this technology can be used in a reproducible way, to activate these regeneration pathways.”
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Wound healing Research is still at a relatively early stage, with Dr Moros currently working to produce the engineered cadherin fragments to place on top of the nanoparticles, conduct the functionalisation process, and bring together several other strands of research. There are many different parts of the puzzle, but the results so far are positive. “We have had good results with the magnetic nanoparticles and we have the protein fragments,” says Dr Moros. The technology could be extremely useful for studying mechanotransduction processes, about which much remains to be learnt, with Dr Moros saying it holds some significant advantages over the available alternatives. “This technology could be applied in vivo and in deep tissues, and we’re looking to achieve precise spatial and temporal control,” she outlines. “A second area of application is in wound healing – in the long-term, it could be used in Crohn’s disease for example.” This is not an immediate prospect however, and at the moment research is more fundamental in nature. At the moment Dr Moros is investigating cadherins typical of epithelial cells, using in vitro models of the skin. “We are now seeing that we have achieved a degree of specificity. These magnetic nanoparticles mainly attach in cells that have this cadherin presence.” But in future she could broaden out her research to look at other types of cadherins. “There are also other cadherins that are present on other types of cells. Later on we could start changing the cadherins on the nanoparticles to study other cell types or pathways,” she says. The project is set to run until the Spring of 2025, with Dr Moros and her colleagues working to improve and refine the technology in what is a relatively new area of research. Confirmation that these regeneration pathways can indeed be activated with this technology would represent good progress, says Dr Moros, and provide solid foundations for further development. “Once we can activate these pathways, we can then look at accelerating the regeneration of tissue,” she says.
Project Funding
The SIROCCO project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 853468).
Contact Details
Project Coordinator, Dr María Moros Instituto de Nanociencia y Materiales de Aragón(INMA) Edificio Circe C/Mariano Esquillor 15 50018 Zaragoza (España) T: +34 876555647 E: mamoros@unizar.es W: http://morosmaria.com
Dr María Moros
My research focuses on the synthesis and smart functionalization of magnetic nanoparticles (MNPs) for biomedical applications. To test the toxicicty and the activity of these materials I pioneered in Spain the use of an invertebrate model organism (Hydra vulgaris), which provides valuable data before reaching vertebrate animals. Inspired by this animal that can fully regenerate, I introduced a new research line that focuses on the remote and temporal activation of intracellular signals using MNPs (magnetogenetics) for regenerative purposes. This line has been awarded with a ERC Starting Grant.
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