Research by a group at Kyoto University has revealed that the evolutionary origin of blood cells is phagocytic cells (macrophages), and that their genetic characteristics have been inherited from the time when they were still single-celled organisms.
Vertebrates such as humans have a variety of blood cells such as erythrocytes, platelets, macrophages, and lymphocytes. It isFrom this, it has been speculated that various blood cells have evolved from macrophages.
However, since the genetic evidence supporting this hypothesis was scarce, this time we comprehensively compared the gene expression states of a wide range of organisms, from mice to unicellular organisms, to determine whether macrophages are the origin of blood cells. I verified what.
First, when we compared the expression status of homologous gene groups among the four species of mouse, sea squirt, sponge, and capsaspora (single-celled organisms), we found that the expression status of phagocytic cells and capsaspora of mouse, sea squirt, and sponge were similar to each other. pinpointed.Furthermore, as a result of searching for genes that regulate this similarity, high expression of the transcription factor CEBPα was observed in both phagocytic cells and Capsaspora.
To investigate the function of CEBPα, mouse, sea squirt, sponge, and capsaspora CEBPα were expressed in mouse B cells and megakaryocyte progenitor cells, and all of them converted to macrophages.This indicates that the function of CEBPα to induce the conversion program to macrophages has been conserved from the era of single-celled organisms to vertebrates.
In vertebrates, we also found that polycomb suppresses CEBPα, allowing for the existence of diverse blood cells.When Polycomb is deleted in mouse blood cells, the expression of CEBPα is increased and each cell is transformed into macrophages, as if evolutionarily rewinds to a macrophage-only state similar to primitive animal blood. became.The resulting macrophages looked more like capsaspora (single-celled organisms) than normal cells, and were also leukemia-like.
These results clarified that macrophages are primitive cells and the prototype of all blood cells.These results will deepen our understanding of the evolution of blood cells and contribute to the study of blood diseases. Applications are also expected.
Paper information:[Blood] Tracing the evolutionary history of blood cells to the unicellular ancestor of animals
