TY - JOUR
T1 - Mitochondrial catalase overexpressed transgenic mice are protected against lung fibrosis in part via preventing alveolar epithelial cell mitochondrial DNA damage
AU - Kim, Seok Jo
AU - Cheresh, Paul
AU - Jablonski, Renea P.
AU - Morales-Nebreda, Luisa
AU - Cheng, Yuan
AU - Hogan, Erin
AU - Yeldandi, Anjana
AU - Chi, Monica
AU - Piseaux, Raul
AU - Ridge, Karen
AU - Michael Hart, C.
AU - Chandel, Navdeep
AU - Scott Budinger, G. R.
AU - Kamp, David W.
N1 - Publisher Copyright:
© 2016
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Rationale Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung. Objective To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis. Methods Crocidolite asbestos (100 µg/50 µL), TiO2 (negative control), bleomycin (0.025 units/50 µL), or PBS was instilled intratracheally in 8–10 week-old wild-type (WT - C57Bl/6 J) or MCAT mice. The lungs were harvested at 21 d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay. Results Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced. Conclusions Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role for AEC mitochondrial H2O2-induced mtDNA damage in promoting lung fibrosis. We reason that strategies aimed at limiting AEC mtDNA damage arising from excess mitochondrial H2O2 production may be a novel therapeutic target for mitigating pulmonary fibrosis.
AB - Rationale Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung. Objective To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis. Methods Crocidolite asbestos (100 µg/50 µL), TiO2 (negative control), bleomycin (0.025 units/50 µL), or PBS was instilled intratracheally in 8–10 week-old wild-type (WT - C57Bl/6 J) or MCAT mice. The lungs were harvested at 21 d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay. Results Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced. Conclusions Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role for AEC mitochondrial H2O2-induced mtDNA damage in promoting lung fibrosis. We reason that strategies aimed at limiting AEC mtDNA damage arising from excess mitochondrial H2O2 production may be a novel therapeutic target for mitigating pulmonary fibrosis.
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U2 - 10.1016/j.freeradbiomed.2016.11.007
DO - 10.1016/j.freeradbiomed.2016.11.007
M3 - Article
C2 - 27840320
AN - SCOPUS:84995646282
SN - 0891-5849
VL - 101
SP - 482
EP - 490
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
ER -