Scientists Engineer Starfish Cells to Shape-Shift in Response To Light
By Jill Dando News
Life begins with a single cell in motion. In response to signals from proteins and enzymes, a cell moves, contracts, pinches, and divides.
As daughter cells grow and differentiate, they form a complete organism. Massachusetts Institute of Technology (MIT) scientists have now used light to control a cell's movement during its early development.
Studying egg cells from starfish, a classic model for cell growth, they focused on an enzyme that triggers cell motion.
By genetically modifying the enzyme to respond to light, they could stimulate the cells to move and change shape predictably. They could induce small pinches or larger contractions, even stretching a cell from a circle to a square.
Their findings, published in Nature Physics, offer a new tool for controlling cell shapes during early development.
This could lead to synthetic cells that respond to light, such as therapeutic cells for wound healing or drug delivery.
Senior author Nikta Fakhri says the work helps uncover how living systems self-organize and evolve shape.
Fakhri's group at MIT is particularly interested in symmetry during cell growth and development. The starfish is an ideal model because its cells start symmetrically, then become bilaterally symmetric larvae, and later develop pentameral adult symmetry.
Scientists have discovered that a "circuitry" in the starfish egg cell controls its shape and movement, involving an enzyme called GEF that activates Rho, a protein essential for cell mechanics.
Fakhri's team previously showed that altering GEF levels could change a cell’s movements. Building on this, they used optogenetics, engineering the GEF enzyme to respond to light. They injected mRNA into egg cells, causing them to produce light-sensitive GEF enzymes. When light was applied in specific patterns, the enzyme activated Rho, which triggered the cell to contract or change shape.
The researchers discovered that shining light at one spot could cause sweeping contractions if the enzyme concentration was high enough.
They created a theoretical framework to predict how cells would change shape with different light stimuli. Fakhri sees this work as a blueprint for designing programmable synthetic cells for future biomedical applications.
This research was supported by the Sloan Foundation and the National Science Foundation.
