Crayfish turn blood cells to brain cells

New Scientist elaborates on activity in the niche: ‘In crayfish, blood cells [haemocytes] are attracted to the niche. On any given day, there are a hundred or so cells in this area. Each cell will split into two daughter cells, precursors to full neurons, both of which migrate out of the niche.’ The final development stage of these neurons is completed in clusters in another part of the brain.

The research team used a chemical called astakine 1 to control the production of haemocytes. They found that tweaking the number of haemocytes changed the number of cells in the niche. As New Scientist succinctly reports. ‘More haemocytes meant more baby neurons’.

Next, they extracted blood cells from donor crayfish and marked them with a DNA dye. These cells were then transfused into the subjects of the study. World Nature News reports on the results: ‘More than a week later, the researchers found that the donor blood cells had found their way into the neural nursery. Soon after, new precursor cells were found boasting the same genetic marker, indicating that these baby neurons somehow were created from the donor blood cells.’

As the summary published in Developmental Cell concludes, ‘Adult-born neurons in crayfish can be derived from hemocytes […] Moreover, the number of cells composing the neurogenic niche in crayfish is tightly correlated with total hemocyte counts (THCs) and can be manipulated by raising or lowering THC.’

These results are so noteworthy because they show a remarkable case of transdifferentiation – one of the biggest challenges for regenerative medicine – happening naturally in an invertebrate. However this study is certainly not the end of the exploration. Exactly how the blood cells are reprogrammed to become brain cells is still a mystery, Barbara Beltz of Wellesley College in Massachusetts and a member of the research team, tells New Scientist. Understanding the mechanism, she adds, could help us devise new therapies to reprogramme human cells.