This chart says that old stem cells, that give birth to blood cells, have much much more Wnt5a protein than the young stem cells. The canonical Wnt signaling cascade changes to the non-canonical one that produces more Wnt5a product. This observation was done by a group of scientists at the universities of Ulm and Muenchen, Germany and was published in Nature. So, why is this such a special observation?
Well, because it gives us a clue to what can be done to rejuvenate our blood producing stem cells. We can “turn off” the Wnt5a gene and make the old stem cells young again, which was successfully done by the authors of the experiment. The researchers took the short hairpin RNA and inserted it into the stem cells using a lentivirus. This hairpin RNA blocks translation of the Wnt5a protein sort of like a blank plug. So, these cells were transplanted into mice and those mice showed improved B lymphopoiesis and peripheral blood differentiation profile overall more similar to the one characteristic of young mice. This can one day become a therapy for humans. We could periodically receive such transplantations of our own hematopoietic stem cells, rejuvenated using gene therapy and we could have young blood production again.