The c-Myb target gene neuromedin U functions as a novel cofactor during the early stages of erythropoiesis

• Published in: Blood 2011-05, Vol.117 (21), p.5733-5743
• Main Authors: Gambone, Julia E., Dusaban, Stephanie S., Loperena, Roxana, Nakata, Yuji, Shetzline, Susan E.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blotting, Western; Cell Differentiation; Cells, Cultured; Chromatin Immunoprecipitation; Colony-Forming Units Assay; Erythroblasts - metabolism; Erythroid Precursor Cells - metabolism; Erythropoiesis - physiology; Flow Cytometry; Fluorescent Antibody Technique; Hematologic and hematopoietic diseases; Humans; Luciferases - metabolism; Medical sciences; Neuropeptides - antagonists & inhibitors; Neuropeptides - genetics; Neuropeptides - metabolism; Peptide Fragments - pharmacology; Proto-Oncogene Proteins c-myb - antagonists & inhibitors; Proto-Oncogene Proteins c-myb - genetics; Proto-Oncogene Proteins c-myb - metabolism; Receptors, Neurotransmitter - antagonists & inhibitors; Receptors, Neurotransmitter - genetics; Receptors, Neurotransmitter - metabolism; Red Cells, Iron, and Erythropoiesis; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Small Interfering - genetics
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2009-09-242131

The requirement of c-Myb during erythropoiesis spurred an interest in identifying c-Myb target genes that are important for erythroid development. Here, we determined that the neuropeptide neuromedin U (NmU) is a c-Myb target gene. Silencing NmU, c-myb, or NmU's cognate receptor NMUR1 expression in human CD34+ cells impaired burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) formation compared with control. Exogenous addition of NmU peptide to NmU or c-myb siRNA-treated CD34+ cells rescued BFU-E and yielded a greater number of CFU-E than observed with control. No rescue of BFU-E and CFU-E growth was observed when NmU peptide was exogenously added to NMUR1 siRNA-treated cells compared with NMUR1 siRNA-treated cells cultured without NmU peptide. In K562 and CD34+ cells, NmU activated protein kinase C-βII, a factor associated with hematopoietic differentiation-proliferation. CD34+ cells cultured under erythroid-inducing conditions, with NmU peptide and erythropoietin added at day 6, revealed an increase in endogenous NmU and c-myb gene expression at day 8 and a 16% expansion of early erythroblasts at day 10 compared to cultures without NmU peptide. Combined, these data strongly support that the c-Myb target gene NmU functions as a novel cofactor for erythropoiesis and expands early erythroblasts.