Fig 1: DJ001 promotes HSC regeneration via RAC1 activation and induction of BCL-XL. a %p250GAP phospho-tyrosine (pTyr) in BM lin- cells cultured ± DJ001 (media, n = 10; DJ001, n = 7). b At left, representative images of PLA in BM KSL cells treated ± DJ001. Red = DsRed+, PTPs-p250GAP complex; blue = DAPI, original magnification ×63, scale bars = 10 µm). At right, numbers of DsRed+ KSL cells in each condition (n = 48, control; n = 36, DJ001). c %RAC1-GTP+ KSL cells from Ptprs+/+ and Ptprs-/- mice treated ± DJ001 (n = 5). Two-way ANOVA with Sidak’s multiple comparison test. d Percentages of p-PAK1+ KSL cells following treatment with media alone, 1 µg/mL DJ001, or DJ001 + 6 µg/mL EHT1864 (n = 5). One-way ANOVA with Tukey’s multiple comparison test. e At left, Annexin V/7AAD staining of BM KSL cells from mice at 24 h post 500 cGy and treatment with vehicle, 5 mg/kg DJ001, DJ001 + 40 mg/kg EHT1864, or EHT1864 alone. Numbers represent percentages in each gate. At right, %Annexin+7AAD- BM KSL cells (media and DJ001, n = 9; DJ001 + EHT1864, n = 7; EHT1864, n = 4). f Percent survival of mice following 750 cGy and 10-day treatment with DJ001 (11/15 alive), vehicle (4/15 alive), or DJ001 + EHT1864 (2/15 alive; Log-rank test). g Fold changes (2-??Ct) of gene expression in BM KSL cells at 12 h post 300 cGy and treatment with or without DJ001 (n = 3–6/group). Two-way ANOVA with Sidak’s multiple comparison test. h At left, BCL-XL protein levels in non-irradiated BM KSL cells (red), 300 cGy-irradiated KSL cells in media alone (black) or treated with DJ001 (blue) or DJ001 + EHT1864 (gray). At right, %BCL-XL+ KSL cells (n = 6). One-way ANOVA with Tukey’s multiple comparison test. i CFCs from BM KSL cells at 48 h following 300 cGy and culture with and without DJ001, and with and without shRac1 or shBcl2l1 (n = 3–9/group). Two-way ANOVA with Sidak’s multiple comparison test. Error bars represent SEM. Source data are provided as Source Data File. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001