LepR+ cell–derived VEGF-C contributes to maintenance of functional HSCs in the BM. (A) Experimental setup for evaluating the effects of LepR+ cell–derived VEGF-C. Vegfc was deleted from LepR+ cells using Lepr-Cre. BM of 7- to 10-week-old mice was analyzed for niche cell and HSC phenotypes. WBM from 10-week-old VcΔLepr or Vcfl/fl mice was transplanted competitively with CD45.1 WBM into lethally irradiated CD45.1 mice. (B) Representative confocal immunofluorescence images of femur sections from VcΔLepr and Vcfl/fl littermate controls stained for ECs (endomucin, green) and LepR+ perivascular cells (red), with quantification (right) (n = 6-7 mice per group). Bar represents 50 μm. (C) Quantification of HSPC subsets per femur from VcΔLepr and Vcfl/fl littermate control mice (n = 4 mice per group) determined by CD48 and CD150 staining. (D) Competitive transplantation of WBM from VcΔLepr and their Vcfl/fl littermate control mice into lethally irradiated WT CD45.1 recipients (2 independent transplants with 3 to 4 recipients per condition per transplant). Shown is a multilineage donor chimerism from peripheral blood at the indicated time points after competitive transplantation. (E) Quantification of LKS cells derived from VcΔLepr or Vcfl/fl mouse BM 16 weeks after transplantation. Values show means ± SD. Statistical significance was determined using the 2-tailed, unpaired Student t test. *P < .05; **P < .01.