A group of biologists and mathematicians from the universities of Münster and Erlangen-Nuremberg have developed a new method for analyzing the processes of cell migration in living organisms.
The researchers studied how primordial germ cells, whose mode of locomotion is similar to other types of migratory cells, such as cancer cells, behave in zebrafish embryos.
The team has developed new software that allows 3D microscopic images of multiple embryos to be combined to identify patterns in cell distribution. In this way, tissues that affect cell migration can be isolated.
Using the software, the researchers identified the domains that cells either avoided, to which they responded by clustering, or in which they maintained their normal distribution. Thus, they identified a physical barrier at the border of the body’s future spine, where the cells change their path.
The researchers used primary germ cells from zebrafish embryos. The article notes that the primary germ cells are the precursors of sperm and eggs: in the process of development of many organisms, they migrate to the places where the reproductive organs are formed. Typically, these cells are controlled by chemokines or attractants produced by surrounding cells, which initiate signaling pathways by binding to receptors on primary germ cells.
By genetically modifying the cells, the scientists deactivated the chemokine receptor Cxcr4b so that the cells remained motile but no longer migrated in a directed manner.
Using the new software, the researchers combined microscopic images of hundreds of zebrafish embryos. This allowed them to identify patterns in how primordial germ cells behave in the absence of the Cxr4b attractant receptor. They found that tissue along the longitudinal axis of embryos acts as a physical barrier, influencing the direction of movement of cells and inhibiting cell migration through the tissue.