(A) Treatment with the cGAS inhibitor increased GATA1 transcription (n = 4) in MDS BM-MNCs, differentiation evidenced by Wright-Giemsa staining (n = 2) (B), and CD71 expression (n = 3); representative flow histogram (C) in MDS BM-MNCs. The original image was taken with a 40× objective on EVOS FL Auto microscope. (D) BM-MNC ASC specks decreased in Tet2–/– CD45.2 BM-MNCs treated in vivo for 6 weeks with RU.521 compared with vehicle (n = 3, each); (E) increased erythroid islands in the bone marrow from mice treated with RU.521compared with mice treated with vehicle; and (F) increased hemoglobin, hematocrit, and lymphocytes and decreased monocytes in treated mice (n = 8) compared with vehicle (n = 9). Data are presented as mean ± SEM. Student’s t test; *P ≤ 0.05.