Contribution of proliferation and DNA damage repair to alveolar epithelial type 2 cell recovery from hyperoxia.
In this study, C57BL/6J mice were exposed to hyperoxia and allowed to recover in room air. The sublethal dose of hyperoxia for C57BL/6J was 48 h. Distal lung cellular isolates from treated animals were characterized as 98% epithelial, with minor fibroblast and endothelial cell contaminants. Cells were then verified as 95% pure alveolar epithelial type II cells (AEC2) by surfactant protein C (SP-C) expression. After hyperoxia exposure in vivo, fresh, uncultured AEC2 were analyzed for proliferation by cell yield, cell cycle, PCNA expression, and telomerase activity. DNA damage was assessed by TdT-dUTP nick-end labeling, whereas induction of DNA repair was evaluated by GADD-153 expression. A baseline level for proliferation and damage was observed in cells from control animals that did not alter significantly during acute hyperoxia exposure. However, a rise in these markers was observed 24 h into recovery. Over 72 h of recovery, markers for proliferation remained elevated, whereas those for DNA damage and repair peaked at 48 h and then returned back to baseline. The expression of GADD-153 followed a distinct course, rising significantly during acute exposure and peaking at 48 h recovery. These data demonstrate that in healthy, adult male C57BL/6J mice, AEC2 proliferation, damage, and repair follow separate courses during hyperoxia recovery and that both proliferation and efficient repair may be required to ensure AEC2 survival.
Lee
Jooeun
J
Department of Surgery and Developmental Biology Program and Division of Research Immunology/Bone Marrow Transplant, The Saban Institute for Research, Childrens Hospital Los Angeles, Los Angeles, CA 90027, USA.
Reddy
Raghava
R
Barsky
Lora
L
Weinberg
Kenneth
K
Driscoll
Barbara
B
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D004249:DNA Damage; D004260:DNA Repair; D004847:Epithelial Cells / Q000145:classification / Q000378:metabolism; D018496:Hyperoxia / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D007633:Keratins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D037721:Pulmonary Surfactant-Associated Protein C / Q000378:metabolism; D020127:Recovery of Function; D016196:S Phase; D019098:Telomerase / Q000378:metabolism; D013997:Time Factors; D051742:Transcription Factor CHOP / Q000378:metabolism; D015854:Up-Regulation
D015415:Biomarkers; C497250:Ddit3 protein, mouse; D018809:Proliferating Cell Nuclear Antigen; D037721:Pulmonary Surfactant-Associated Protein C; D051742:Transcription Factor CHOP; D007633:Keratins; D019098:Telomerase