A change in the number of CCSP(pos)/SPC(pos) cells in mouse lung during development, growth, and repair.
BACKGROUND
Putative resident stem/progenitor cells have been identified in the bronchoalveolar duct junction (BADJ) of the murine lung. However, the contribution of stem cells expressing both Clara cell secretory protein (CCSP) and pro-surfactant protein C (SP-C) to the repair and maintenance of normal homeostasis is still unclear. In this study, we identified and then quantified CD45(neg)/CCSP(pos)/SP-C(pos) cell numbers in normal and lung-injured mice.


METHODS
Normal lung tissues of fetal, newborn, and adult mice were used to evaluate lung progenitor cells during development and growth. Mice treated with naphthalene were used for the bronchiolar epithelium injury model, and mice treated with bleomycin were used for the alveolar epithelium injury model. These lung tissues were stained with CD45, CCSP, and SP-C antibodies by immunofluorescence. The number of lung progenitor cells was counted as CD45(neg)/CCSP(pos)/SP-C(pos) cells by flow cytometry.


RESULTS
CCSP(pos)/SP-C(pos) epithelial cells in the BADJ were identified from E18 to 7 months after birth. The percentage of CD45(neg)/CCSP(pos)/SP-C(pos) cells was relatively stable to 7 months (between 0.3±0.04% and 1.28±0.11%). When lungs were treated with naphthalene, the proliferation of CCSP(pos)/SP-C(pos) cells was observed as patches of double-positive cells and preceded the recovery of bronchioles. In contrast, when lungs were treated with bleomycin, the proliferation of CCSP(pos)/SP-C(pos) cells was observed, but the type II alveolar epithelial cells never recovered to baseline.


CONCLUSIONS
CCSP(pos)/SP-C(pos) lung cells were stable until 7 months after birth. These cells in the BADJ primarily regenerate bronchiolar epithelial cells and not alveolar epithelial cells.
Department of Medical Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifucho, Hirosaki 036-8562, Japan; Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan; Division of Pediatric Hematology, Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China. Electronic address: kiadult@hotmail.com.
Ruowen
R
Sun
Qiliang
Q
Zhou
Xulu
X
Ye
Takenori
T
Takahata
Atsushi
A
Ishiguro
Hiroshi
H
Kijima
Toshihiro
T
Nukiwa
Yasuo
Y
Saijo
D055371:Acute Lung Injury / Q000139:chemically induced / Q000473:pathology*; D000818:Animals; D001761:Bleomycin; D001980:Bronchi / Q000166:cytology / Q000473:pathology; D002452:Cell Count; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D051379:Mice; D009281:Naphthalenes; D010455:Peptides / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000473:pathology; D013234:Stem Cells / Q000378:metabolism*; D014598:Uteroglobin / Q000378:metabolism*
D009281:Naphthalenes; D010455:Peptides; D001761:Bleomycin; C077063:Sftpc protein, rat; C031721:naphthalene; D014598:Uteroglobin
BADJ; BASCs; CCSP; Clara cell secretory protein; E; FACS; Growth; IgG; Lung progenitor cells; PBS; Repair; SP-C; bronchoalveolar duct junction; bronchoalveolar stem cells; embryonic day; fluorescence-activated cell sorter; immunoglobulin G; phosphate-buffered saline; pro-surfactant protein C