A team of researchers used light to control the way a single cell stirs and moves during its early development phase. Investigation may allow the design of light -activated synthetic cells for wound healing or drug administration.
Life takes shape with the movement of a single cell. In response to signs of certain proteins and enzymes, a cell can begin to move and stir, leading to contractions that make it squeeze, tighten and eventually divide.
As the daughters cells follow themselves in the generational line, they grow, differentiate each other and, finally, They are organized in an organism completely formed.
Now a team of MIT researchers has used light to control the way A single cell shakes and moves during its initial development phase.
The team studied the movement of eggs produced by staran organism that scientists They have long used as a classic model to understand cell growth and development.
The researchers focused on a key enzyme that triggers a cascade of movements inside a sea star egg. Genetically conceived a Light -sensitive version of the same enzymewhich injected into the eggs, and then stimulated cells with different light patterns.
Found that light could activate the enzyme, which in turn brought cells to shake and move in predictable standards.
For example, scientists managed to stimulate cells to display small Broad pinches or contractionsdepending on the standard of light they induced, and even illuminate specific points around a cell to stretch your form of a circle for a square.
The results of the last week published in Nature Physicsprovide scientists with a new optical instrument for control cell shape in their early stages of development.
This tool can guide the conception of synthetic cellssuch as therapeutic cells that contract in response to light signs to help close “carriers” wounds or cells of medicines that only release their content when lit in specific places of the body.
The results of this study can also help scientists to investigate how life takes shape from a single cell.
“By revealing the way a light-activated switch can reshape real-time cells, we are discovering the basic principles of conception of the way living systems are self-organized and evolving,” he says Nikta fakhriMIT Physics Professor and Main Author of the Study at the University.
“The power of these tools is that they guide us in decoding all these growth and development processes, to help us understand How nature does“Adds the researcher.
Fakhri’s team in MIT is particularly interested in the governing processes the way cells follow or break symmetry as they grow and divide. THE five-member starhe explains, it is an ideal organism to explore these issues of growth, symmetry and initial development.
“The starfish is a fascinating system: It starts with a symmetrical cell and becomes a larva bilaterally symmetrical in the initial phasesthen developing an adult pentameral symmetry, ”says Fakhri.
“Therefore, there are all these signaling processes that happen along the way to say to the cell how to organize“He adds.
A key circuit
Scientists have long been studying the star and their various phases of development. Among many revelations, the researchers discovered a “Key circuit” within an embryonic cell from the starfish that controls its movement and shape.
This circuit involves an enzyme, Gef, that naturally circulates in the cytoplasm of a cell. When this enzyme is activated, induces a change in a proteincalled RHO, which is known to be essential to regulate cellular mechanics.
When the GEF enzyme stimulates the RHO, it causes protein to pass from a state essentially of free fluctuation to a state that connects it to the cell membrane.
In this state of membrane binding, protein then triggers the growth of microscopic fibers, similar to muscleswhich extend through the membrane and subsequently contract, allowing the cell to contract and move.
In previous work, Fakhri’s group showed that the movements of a cell can be manipulated by varying concentrations Gef enzyme in the cell: the more enzyme they introduced into a cell, the more contractions it would present.
“This whole idea made us wonder if this circuit can be piped, not only to change the standard of movements of a cell, but also to get a desired mechanical response,” explains the Iran-American researcher.
1400 Degrees
Nikta Fakhri, physics teacher at Massachusetts Institute of Technology
To accurately manipulate the movements of a cell, the team resorted to Optogeneticsan approach that involves genetic engineering of cells and cellular components, such as proteins and enzymes, so that they are activated in response to light.
Using established optogenetic techniques, the researchers then developed a GEF Enzyme Light Version.
From this modified enzymethey isolated their Arnm – Essentially, the genetic design for the construction of the enzyme. They then injected this project into eggs that the team harvested from a single sea star ovary, which could contain millions of non-fertilized cells.
The cells, infused with the new MRNA, then began to produce Gef enzymes sensitive to light on themselves.
The investigators put each egg infusted with the enzyme under a microscope and made light on the cell in different standards and from different points along the periphery of the cell. In response, the cell movements recorded on video.
Found that, when they pointed the light to specific pointsthe Gef enzyme was activated and recruited the RHO protein to the places targeted by the light.
Then, The protein spoiled its characteristic cascade of fiber similar to muscles that pulled or pinching the cell at the same points stimulated by the light
As if they were pull the strips from a puppetthe investigators managed to control cell movementsfor example, making it turn into various forms, including a square.
Surprisingly, they also found that they could stimulate the cell to suffer radical contractions causing a light on a single pointsurpassing a particular threshold of enzyme concentration.
“We realize that This RHO-GEF circuit is an excitable systemIn which a small, timely stimulus can trigger a large, all or nothing answer, ”says Fakhri.
“So we can illuminate the whole cell or just a small place of the cell, so that a sufficient amount of enzymes is recruited for this region, so that the system is started to contract or compress by itself. ”
The researchers compiled their observations and created a theoretical structure to predict how the shape of a cellA, taking into account the way it is stimulated by light.
The structure, says Fakhri, Opens a window to “” excitability “ In the heart of cell remodeling, which is a fundamental process in embryonic development and wound healing ”.
“The study offers a model for the creation of programmable synthetic cells, that can allow researchers orchestrate changes in a will For future biomedical applications, ”concludes the researcher.
