Wnt signaling in the bloodstream
We have found that components of the Wnt signaling pathways are expressed in erythrocytes and that these cells respond to the Wnt ligands.
We show that the Wnt ligands modulate the erythrocyte cytoskeleton, enabling its flexibility and strength. Furthermore, Wnts prolong erythrocyte survival both ex-vivo, under storage conditions, and in post-transfusion recipient mice. We also demonstrate that a Wnt ligand is secreted into the plasma and that monocytes and lymphocytes express and most likely secrete the Wnt effectors into the circulation.
These findings provide evidence for intracellular signaling activity in enucleated cells and open new avenues for studying the function of signaling pathways in the bloodstream.
The Wnt ligand specifically attaches to the erythrocyte membrane (A) and promotes survival and increased hemoglobin content (B). The Wnt-5A protein is detected in the human plasma (C), secreted by both Monocytes (M) and lymphocytes (L) (D).