title: Melanocortins contribute to sequential differentiation and enucleation of human erythroblasts via melanocortin receptors 1, 2 and 5.
abstract: In this study, we showed that adrenocorticotropic hormone (ACTH) promoted erythroblast differentiation and increased the enucleation ratio of erythroblasts. Because ACTH was contained in hematopoietic medium as contamination, the ratio decreased by the addition of anti-ACTH antibody (Ab). Addition of neutralizing Abs (nAbs) for melanocortin receptors (MCRs) caused erythroblast accumulation at specific stages, i.e., the addition of anti-MC2R nAb led to erythroblast accumulation at the basophilic stage (baso-E), the addition of anti-MC1R nAb caused accumulation at the polychromatic stage (poly-E), and the addition of anti-MC5R nAb caused accumulation at the orthochromatic stage (ortho-E). During erythroblast differentiation, ERK, STAT5, and AKT were consecutively phosphorylated by erythropoietin (EPO). ERK, STAT5, and AKT phosphorylation was inhibited by blocking MC2R, MC1R, and MC5R, respectively. Finally, the phosphorylation of myosin light chain 2, which is essential for the formation of contractile actomyosin rings, was inhibited by anti-MC5R nAb. Taken together, our study suggests that MC2R and MC1R signals are consecutively required for the regulation of EPO signal transduction in erythroblast differentiation, and that MC5R signal transduction is required to induce enucleation. Thus, melanocortin induces proliferation and differentiation at baso-E, and polarization and formation of an actomyosin contractile ring at ortho-E are required for enucleation.
authors: Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Eriko
authors: E
authors: Simamura
authors: Department of Biology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Tomohiro
authors: T
authors: Arikawa
authors: Department of Biochemistry, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Takayuki
authors: T
authors: Ikeda
authors: Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Hiroki
authors: H
authors: Shimada
authors: Department of Biology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Hiroki
authors: H
authors: Shoji
authors: Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Hiroko
authors: H
authors: Masuta
authors: Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Yuriko
authors: Y
authors: Nakajima
authors: Department of Developmental Biology, Faculty of Medicine, Shimane University, Izumo 693-8601, Japan.
authors: Hiroki
authors: H
authors: Otani
authors: Department of Biochemistry, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Hideto
authors: H
authors: Yonekura
authors: Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan.
authors: Toshihisa
authors: T
authors: Hatta
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism; D057134:Antibodies, Neutralizing; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D004900:Erythroblasts / Q000166:cytology* / Q000378:metabolism*; D004920:Erythropoiesis / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D053486:Melanocortins / Q000378:metabolism*; D008954:Models, Biological; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D044102:Receptor, Melanocortin, Type 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D044103:Receptor, Melanocortin, Type 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D044101:Receptors, Melanocortin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D057134:Antibodies, Neutralizing; D053486:Melanocortins; D044102:Receptor, Melanocortin, Type 1; D044103:Receptor, Melanocortin, Type 2; D044101:Receptors, Melanocortin; D050799:STAT5 Transcription Factor; C086971:melanocortin 5 receptor; D000324:Adrenocorticotropic Hormone; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases