Figure 5. Endogenous bone marrow Ccsp⁺ cells can respond to airway injury.

Ccsp protein was detected in the bone marrow and lungs of bone marrow–transplanted Ccsp knockout animals. (A) Bone marrow and peripheral blood of mice after naphthalene-induced airway injury showed a transient increase in Ccsp⁺ cells, peaking at 2 days of airway injury and declining to baseline levels by 20 days. n = 4 mice per group. *P < 0.01 compared with uninjured peripheral blood group; ^†P < 0.05 compared with uninjured bone marrow group. (B) Strategy of the bone marrow transplants. (C) Flow cytometry of bone marrow transplantation of wild-type whole marrow showed existence of Ccsp⁺ BMCs, which increased with airway injury. No detectable Ccsp⁺ BMCs was found in mice that received Ccsp knockout marrow with or without airway injury. Percentages indicate percentage of cells above background fluorescence. Arrows indicate part of histogram at which cells were positive for Ccsp. (D) Western blot confirmed the presence of the 11-kDa band corresponding to the Ccsp protein in the lungs and kidneys of mice that received wild-type but not Ccsp knockout marrow.