Dynamic changes in bone marrow JAM-B expressing stromal cells after 5-FU treatment. (A) The survival curves of jam-b deficient (square) and wild-type control mice (circle) that received 5FU (120 mg/kg) once a week are shown. The survival median for jam-b deficient mice is 18.5 days whereas all control mice were still alive 25 days after initiation of 5FU treatment Results are representative of at least 3 independent experiments, n = 6. (B) The graph represents the leukocyte count in the blood of control mice after a single injection of 5-FU. There is a strong decrease of circulating leukocytes between day 3 and 4 after 5-FU injection. (C) Representative flow cytometry profiles showing the bone marrow stromal composition of control and jam-b deficient mice 3 days after a single injection of 5-FU. The percentages of ECs, OBs, and MSCs are shown. (D) Representative flow cytometry profiles showing the different stromal subsets expressing JAM-B before or 3 days after 5-FU treatment of wild-type mice. A 2-fold decrease in the proportion of stromal cells expressing JAM-B is observed on 5-FU treatment (1.1% vs 2.2%) with a specific decrease in the proportion of MSCs (2% vs 9%). Bones of 6 mice of each group were pooled to obtain enough cells. (E) Confocal images of 20-μm-thick femoral sections obtained from control or 5-FU treated mice and stained with the indicated markers. Both JAM-B and CD31 signals are reduced after 5-FU treatment. The graph in the left panel show a quantification of CD31 and JAM-B staining observed on 8 femoral sections of control (black bars) and 5-FU treated mice (mice bar). Results are representative of at least 3 independent experiments with at least 5 mice per group.