<scp>MiR</scp> ‐513a promotes human erythroid differentiation by modulating c‐Jun

Erythropoiesis is a highly coordinated process that generates mature red blood cells from hematopoietic stem-progenitor cells (HSPCs). Erythropoietin (EPO) is a major regulator of erythropoiesis and binds to the erythropoietin receptor (EPOR), leading to increased erythroid differentiation and proliferation. MicroRNAs (miRs) are important developmental regulators, and distinct miR expression patterns are associated with specific stages of hematopoietic differentiation. Expression profiling of EPO-stimulated human HSPCs revealed increased expression of miR-513a-5p in early erythroid cells. Enforced expression of miR-513a in primary human CD34⁺ HSPCs promoted erythroid differentiation, as determined by cell-surface marker expression and increased levels of erythroid molecules including hemoglobin. Similar results were observed in human TF-1 erythroleukemia cells, where miR-513a stimulated erythroid differentiation including increased GATA1 and hemoglobin expression and decreased GATA2 expression, even in the absence of EPO. Notably, miR-513a promoted erythroid differentiation in EPOR knockout (KO) TF-1 cells, but not in GATA1 KO TF-1 cells, indicating that miR-513a requires GATA1, but not EPOR, to stimulate erythropoiesis. Further analysis revealed that enforced expression of miR-513a was associated with reduced c-Jun and phospho-c-Jun protein levels. Overexpression of c-Jun inhibited both EPO- and miR-513a-stimulated erythropoiesis. Conversely, c-Jun KO TF-1 cells had increased hemoglobin protein expression, even in the absence of EPO, phenocopying miR-513a overexpression. In summary, this study identifies miR-513a as a positive regulator of early human erythropoiesis and supports a role for miR-513a in promoting erythroid differentiation by modulating c-Jun expression and increasing GATA1 expression.