EML Erythroid and Neutrophil Differentiation Protocols

Erythroid-Myeloid-Lymphoid cells (EML) are a multipotent haematopoietic cell line of mouse bone marrow origin capable of long-term maintenance in vitro in the presence of SCF (stem cell factor) (Tsai et al., 1994). The self-renewal capacity of the EML cell line is conferred by the presence of a dominant-negative retinoic acid receptor (RAR) originally delivered by retroviral transduction (Tsai et al., 1994), which arrests cells at an early progenitor stage blocked from normal progression into myeloid differentiation. The presence of the RAR trans-gene does not interfere with erythroid differentiation, and it is possible to capture a low percentage of early erythroid, but not myeloid, committed cells in maintenance cultures (Pina et al., 2012; Ye et al., 2005).Cells can be driven into granulocytic/neutrophil differentiation through the use of high doses of retinoic acid (RA), which overcomes the differentiation block. It should be noted that these pharmacological doses of RA are not compatible with erythroid differentiation, and it is hence not viable to obtain robust erythroid and myeloid differentiation in the same assay. Indeed, colonies scored as mixed-lineage in CFC assays are a mixture of undifferentiated and erythroid cells (Tsai et al., 1994). Nevertheless, robust single-lineage erythroid and neutrophil differentiation can be obtained in liquid culture under defined cytokine conditions, as specified below.