Yonsei Med J.  2013 Mar;54(2):445-452. 10.3349/ymj.2013.54.2.445.

Interleukin-10 Down-Regulates Cathepsin B Expression in Fetal Rat Alveolar Type II Cells Exposed to Hyperoxia

• Lee HS
• Kim CK

• KMID: 1503909
• DOI: http://doi.org/10.3349/ymj.2013.54.2.445

Abstract

PURPOSE
Hyperoxia has the chief biological effect of cell death. We have previously reported that cathepsin B (CB) is related to fetal alveolar type II cell (FATIIC) death and pretreatment of recombinant IL-10 (rIL-10) attenuates type II cell death during 65%-hyperoixa. In this study, we investigated what kinds of changes of CB expression are induced in FATIICs at different concentrations of hyperoxia (65%- and 85%-hyperoxia) and whether pretreatment with rIL-10 reduces the expression of CB in FATIICs during hyperoxia.
MATERIALS AND METHODS
Isolated embryonic day 19 fetal rat alveolar type II cells were cultured and exposed to 65%- and 85%-hyperoxia for 12 h and 24 h. Cells in room air were used as controls. Cytotoxicity was assessed by lactate dehydrogenase (LDH) released into the supernatant. Expression of CB was analyzed by fluorescence-based assay upon cell lysis and western blotting, and LDH-release was re-analyzed after preincubation of cathepsin B-inhibitor (CBI). IL-10 production was analyzed by ELISA, and LDH-release was re-assessed after preincubation with rIL-10 and CB expression was re-analyzed by western blotting and real-time PCR.
RESULTS
LDH-release and CB expression in FATIICs were enhanced significantly in an oxygen-concentration-dependent manner during hyperoxia, whereas caspase-3 was not activated. Preincubation of FATIICs with CBI significantly reduced LDH-release during hyperoxia. IL-10-release decreased in an oxygen-concentration-dependent fashion, and preincubation of the cells with rIL-10 significantly reduced cellular necrosis and expression of CB in FATIICs which were exposed to 65%- and 85%-hyperoxia.
CONCLUSION
Our study suggests that CB is enhanced in an oxygen-concentration-dependent manner, and IL-10 has an inhibitory effect on CB expression in FATIICs during hyperoxia.

Keyword

IL-10; cathepsin B; hyperoxia; fetal alveolar type II cells

MeSH Terms

Animals
Cathepsin B/*genetics/metabolism
*Down-Regulation
Gene Expression Regulation
Hyperoxia/*genetics
Interleukin-10/*pharmacology/physiology
L-Lactate Dehydrogenase/metabolism
Necrosis/chemically induced
Oxygen/metabolism
Rats
Interleukin-10
L-Lactate Dehydrogenase
Cathepsin B
Oxygen