Fig. 4: scRNA sequencing reveals a myeloid differentiation bias by GFI1B^Q287* or GSK-LSD1 treatment (LSD1i) during megakaryocyte differentiation of iPSCs.

UMAP showing iPSC-derived wild type (a), GFI1B^Q287* (b), and GSK-LSD1 inhibitor treated (c) cells after megakaryocyte differentiation. Cell type annotation revealed erythroblasts (red), megakaryocytes (dark green), megakaryocyte progenitors (light green), myeloid cell (dark blue), myeloid cell progenitors (light green), and lymphoid-myeloid progenitors (gold). The megakaryocytes and megakaryocyte progenitors to myeloid and myeloid progenitor cell ratio was 5.7, 1.3 and 2.7 for the wild type, GFI1B^Q287* and LSD1i conditions, respectively. d Heatmap showing the activity of gene programs that are regulated by a transcription factor (regulons). SPI1, ETV5 and CEBPA were active in myeloid cells in all conditions. Regulons controlled by megakaryocytic transcription factors such as GATA1, TAL1, and NFE2 were not active in myeloid cells of any condition. e The GATA1, TAL1, and NFE2 regulons were active in 50% of all wild type megakaryocytes or more. NFE2 was not found to be active in GFI1B^Q287* megakaryocytes and GATA1 and TAL1 were active in 22% and 29% of GFI1B^Q287* megakaryocytes, respectively. Myeloid SPI1 and ETV5 were not active in wild type megakaryocytes but showed activity in LSD1i and GFI1B^Q287* megakaryocytes. f Regulon activity was projected onto our UMAP data. The myeloid-related SPI1 regulon was active in myeloid cells in the wild type condition and in all cell types in the GFI1B^Q287* and LSD1i conditions including megakaryocytes. g SCENIC revealed that the ETV5 regulon was only active in myeloid cells in the wild type condition. In contrast, it was active in all cell types in the GFI1B^Q287* and LSD1 inhibitor-treated condition. h The erythro-megakaryocytic GATA1 regulon was active in wild type megakaryocytes. Its activity was reduced in GFI1B^Q287* and LSD1i megakaryocytes. i SCENIC revealed that TAL1 was active in wild type megakaryocytes. The activity of the TAL1 regulon was reduced in LSD1 inhibitor-treated megakaryocytes and almost absent in GFI1B^Q287* megakaryocytes.