Fig 2: Endoglin expression in bone marrow hematopoietic cells. (a) Representative scatter dot-plot images of flow cytometry for the detection of endoglin-positive cells (left) and CD71 and Ter119 expression on endoglin-positive cells (right). (b) Representative scatter dot-plot images of flow cytometry for the detection of LK cells (left) and endoglin expression and binding efficiency of bio-BMP9 on LK cells (right). Note that the fluorescence intensity representing the binding efficiency of bio-BMP9 correlates well with the expression level of endoglin (rectangle in the right panel). (c) Example of the endoglin and CD150 expression profile of fresh bone marrow LK cells gated on Sca1(-)IL7Ra(-)Fc?RII/III(-)CD41(-). The immunophenotypic characteristics with endoglin and CD150 expression for the CFU-E, preCFU-E, preMegE and preGM subgroups are shown. (D) Representative histogram images of flow cytometry showing bio-BMP9 binding to cells in preCFU-E (right) and CFU-E (left) fractions. The gray-filled histogram depicts background fluorescence in the absence of bio-BMP9. The blue and red histograms show the number of cells versus the fluorescence intensity measured in the absence and presence of the neutralizing anti-BMP9 antibody, respectively. Experiments were performed two times

Fig 3: Flow cytometry analysis of erythroid lineage cells in BALB/c mice. The frequencies of CD71(+)Ter119(+) (left) and CD71(-)Ter119(+) (right) cells in mice that received four weekly administrations of the anti-BMP9 antibody are shown. p-values versus the corresponding vehicle group by Wilcoxon rank sum test are indicated