Blood cells feel nervous impulses, reveal findings from Asaf Spiegel, Tsvee Lapidot (Weizmann Institute, Rehovot, Israel), and colleagues. Human blood stem cells express receptors for stress-induced neurotransmitters.
Protective white blood cells swarm into the circulation when the body is in alarm mode. Infection, injury, and even anxiety can cause blood stem cells to proliferate and escape from their birth sites in bone marrow, which is heavily innervated. Lapidot's group now shows that this response stems from receptors on young blood cells that sense stress-induced neurotransmitters such as epinephrine.
Receptor expression was increased by cytokines such as granulocyte colony-stimulating factor (G-CSF), which mobilizes blood progenitor cells. G-CSF is secreted during inflammation and activates early responding immune cells.
The bound receptors activated a known proliferation pathway headed by Wnt and β-catenin. As a result, blood progenitor cells proliferated, polarized, and mobilized in the presence of the neurotransmitters.
Lapidot believes that blood cells aren't picky about their neurotransmitters. “We chose to look at dopamine, epinephrine, and neuroepinephrine,” he says. “But we think others are also involved in stem cell regulation.” His team would now like to determine whether unchecked activation of neurotransmitter pathways also helps blood cancers such as leukemia thrive.