Fig 2: SCGF infusion resolves hematopoietic and vascular defects in CDH5-MAPK mice.a Frequency of phenotypic HSCs per 106 WBM (n = 9–10 mice/cohort). b Representative contour plots demonstrating that SCGF infusion restores phenotypic HSC defects observed in CDH5-MAPK mice. c Methylcellulose-based progenitor assay (n = 5 mice/cohort). d, e Competitive repopulation assay assessing total CD45.2+ cell engraftment and CD45.2+ lineage distribution 4 months post-transplantation (n = 5 recipients/cohort; n = 5 donors per cohort). For competitive repopulation assays, 5 × 105 donor WBM cells (CD45.2) were transplanted along with 5 × 105 competitor WBM cells (CD45.1) into pre-conditioned CD45.1 recipient mice. Note that donor cells derived from SCGF-treated CDH5-MAPK mice displayed a significant increase in engraftment efficiency with the resolution of the myeloid bias and increase in lymphoid output. Also, note that SCGF does not significantly impact the hematopoietic function or phenotype of control mice. f, g Secondary transplantation assay wherein WBM cells from long-term engrafted primary recipients were isolated and transplanted into pre-conditioned CD45.1 recipient mice (2 × 106 donor WBM cells per recipient) (n = 5 recipients/cohort; n = 5 donors per cohort). h Analysis of BM vascular leakiness by Evan’s Blue Dye (EBD) extravasation reveals that SCGF infusion significantly reduces vascular leakiness of CDH5-MAPK mice (n = 3–5 mice/cohort). i Representative immunofluorescence images of femurs intravitally labeled with a vascular-specific VECAD antibody (red) demonstrating reversal of vascular dilatation in CDH5-MAPK mice treated with SCGF. j Normalized gene expression of NF-?B target genes within the BM microenvironment of indicated genotypes as compared to PBS-treated control mice. B2m was used for normalization (n = 3 mice/cohort). k, l Representative immunofluorescence images and quantification demonstrating decreased levels of nuclear p65 in BMECs derived from CDH5-MAPK mice treated with SCGF. Error bars represent sample mean ± SEM. Statistical significance was determined using two-tailed unpaired Student’s t-test for pairwise comparisons (a–j) and one-way ANOVA for multiple comparisons (k). *P = 0.05; **P < 0.01; ***P < 0.001; n.s.P > 0.05.

Fig 3: Schematic describing the impact of inflammation on BM niche cells and HSPCs. Endothelial MAPK activation drives an NF-kB-dependent inflammatory stress response within the bone marrow leading to functional defects in the vascular niche and HSPCs. Suppression of inflammation by inhibition of endothelial NF-kB or infusion of SCGF restores vascular integrity, resolves HSPC and niche defects, and augments post-myelosuppressive hematopoietic recovery.