Effects of PECAM-1−/− deletion on the bone marrow microenvironment.
PECAM-1−/− and WT littermate bone marrow was collected in PBS and analysed for factors important in HSC mobilisation. (A) PECAM-1−/− bone marrow has comparable levels of CXCL12 compared to WT littermates, as measured by ELISA (n = 13). (B) Longitudinal sections of whole murine femora from matched pairs of PECAM-1−/− and WT littermates were immunofluorescently stained for components of the bone marrow microenvironment; CXCL12 (red), VCAM-1 (green) and marrow sinusoidal vessels by endoglin (CD105, blue). Images are representative of at least three pairs of femurs, and images are taken at ×40 magnification. (C.) In-gel zymography demonstrated that PECAM-1−/− bone marrow flushes contained higher levels of MMP-9. Pooled data from 6 litter matched pairs confirmed this to be a significant difference (data shown as the mean±S.D., *p = 0.003).