Insulin, nutrition prevent blood stem cell differentiation in the fruit fly

UCLA stem cell researchers have shown that insulin and nutrition prevent blood stem cells from differentiating into mature blood cells in Drosophila, the common fruit fly, a finding that has implications for studying inflammatory response and blood development in response to dietary changes in humans. Keeping blood stem cells, or progenitor cells, from differentiating into blood cells is important as blood stem cells are needed to create the blood supply for the adult fruit fly. The study found that the blood stem cells are receiving systemic signals from insulin and nutritional factors, in this case essential amino acids, that helped them to maintain their "stemness," said study senior author Utpal Banerjee, the Irving and Jean Stone Professor and chairman of molecular, cell and developmental biology in the UCLA Division of Life Sciences and a researcher with the Eli and Edythe Broad Center of Regenerative Medicine at UCLA. "We expect that this study will promote further investigation of possible direct signal sensing mechanisms by mammalian blood stem cells," Banerjee said. "Such studies will probably yield insights into chronic inflammation and the myeloid cell accumulation seen in patients with type II diabetes and other metabolic disorders." In the flies, the insulin signaling came from the brain, which is an organ similar to the human pancreas, which produces insulin. That insulin was taken up by the blood stem cells, as were amino acids found in the fly blood, said Ji Won Shim, a postdoctoral fellow in Banerjee's lab and first author of the study.