In 2017 we identified cxcr1, the specific receptor for the angiogenic chemokine, cxcl8, as a factor that acts in the niche to promote hematopoietic stem and progenitor cell (HSPC) engraftment. Using time-lapse video microscopy, we showed that cxcr1 expands stem cells in zebrafish embryos by increasing the amount of time they interact with their microenvironment and increasing their cell division rate. Cxcr1 also expands the microenvironment and induces expression of the critical chemokine, cxcl12. Experiments with parabiotic zebrafish showed that this effect was autonomous to the niche. This study suggests that factors such as cxcl8 may be useful to improve stem cell engraftment in patients receiving hematopoietic stem cell transplantation.
In this article, we provide a step-by-step method for generating parabiotic zebrafish. This is a powerful technique for understanding how cells migrate and interact with their microenvironment. By fusing two genetically distinct zebrafish lines, we can understand how certain factors operate in a cell autonomous or non-autonomous fashion.