Effect of chronic hypoxia on proliferation, apoptosis, and HSP70 expression in mouse bronchiolar epithelial cells.
Heat shock proteins (HSPs) can be induced by various stresses and play an important role in cell cycle progression. HSP70 has been shown to act as an inhibitor of apoptosis. We studied HSP70 expression in bronchial epithelial cells of C57BL/6 mice and homozygous HPS70 knockout mice (hsp70.1-/-) exposed to chronic hypoxic stress. We also investigated changes in cellular proliferation and apoptosis in relation to HSP70. Lungs were removed from mice after a three-week period of exposure to 10 % O(2). Immunoblots for HSP70 and immunohistochemical staining for HSP70 and Ki-67 were performed. Apoptosis was assessed using the TUNEL assay. The three-week period of hypoxic stress did not change HSP70 levels in total lung tissue, but a significant reduction in HSP70 expression was observed in bronchiolar epithelial cells. In wild type mice, both HSP70 and Ki-67 expression were significantly reduced in bronchiolar epithelial cells. In homozygous HPS70 knockout mice (hsp70.1-/-), apoptosis of bronchiolar epithelial cells was significantly increased. Our results suggest that HSP70 may exert anti-apoptotic effects in mouse bronchiolar epithelial cells.
Kim
Ee-Kyung
EK
Department of Pediatrics, Seoul National University Hospital, 28 Yongon-dong Jongno-gu, Seoul, Korea.
Park
June Dong
JD
Shim
So-Yeon
SY
Kim
Han-Suk
HS
Kim
Beyong Il
BI
Choi
Jung-Hwan
JH
Kim
Ji Eun
JE
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D001980:Bronchi / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002455:Cell Division / Q000502:physiology; D002908:Chronic Disease; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation / Q000502:physiology; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020545:Respiratory Mucosa / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology
D018840:HSP70 Heat-Shock Proteins; D019394:Ki-67 Antigen; C498355:Mki67 protein, mouse