Lipopolysaccharide induces apoptotic insults to human alveolar epithelial A549 cells through reactive oxygen species-mediated activation of an intrinsic mitochondrion-dependent pathway

Chi Yuan Chuang, Ta Liang Chen, Yih Giun Cherng, Yu-Ting Tai, Tyng Guey Chen, Ruei Ming Chen

研究成果: 雜誌貢獻文章

49 引文 (Scopus)

摘要

Alveolar type II epithelial cells can regulate immune responses to sepsis-induced acute lung injury. Lipopolysaccharide (LPS), an outer membrane component of Gram-negative bacteria, can cause septic shock. This study was designed to evaluate the cytotoxic effects of LPS on human alveolar epithelial A549 cells and its possible molecular mechanisms. Exposure of A549 cells to LPS decreased cell viability in concentration- and time-dependent manners. In parallel, LPS concentration- and time-dependently induced apoptosis of A549 cells. Meanwhile, LPS only at a high concentration of 10 μg/ml caused mildly necrotic insults to A549 cells. In terms of the mechanism, exposure of A549 cells to LPS increased the levels of cellular nitric oxide and reactive oxygen species (ROS). Pretreatment with N-acetylcysteine (NAC), an antioxidant, significantly lowered LPS-caused enhancement of intracellular ROS in A549 cells and simultaneously attenuated the apoptotic insults. Sequentially, treatment of A549 cells with LPS caused significant decreases in the mitochondrial membrane potential and biosynthesis of adenosine triphosphate. In succession, LPS triggered the release of cytochrome c from the mitochondria to the cytoplasm. Activities of caspase-9 and caspase-6 were subsequently augmented following LPS administration. Consequently, exposure of A549 cells induced DNA fragmentation in a time-dependent manner. Pretreatment of A549 cells with NAC significantly ameliorated LPS-caused alterations in caspase-9 activation and DNA damage. Therefore, this study shows that LPS specifically induces apoptotic insults to human alveolar epithelial cells through ROS-mediated activation of the intrinsic mitochondrion-cytochrome c-caspase protease mechanism.
原文英語
頁(從 - 到)209-218
頁數10
期刊Archives of Toxicology
85
發行號3
DOIs
出版狀態已發佈 - 三月 2011

指紋

Alveolar Epithelial Cells
Mitochondria
Lipopolysaccharides
Reactive Oxygen Species
Chemical activation
Caspase 9
Acetylcysteine
Cytochromes c
A549 Cells
Epithelial Cells
Caspase 6
Membranes
Acute Lung Injury
Mitochondrial Membrane Potential
DNA
Biosynthesis
DNA Fragmentation
Septic Shock
Caspases
Gram-Negative Bacteria

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis

引用此文

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title = "Lipopolysaccharide induces apoptotic insults to human alveolar epithelial A549 cells through reactive oxygen species-mediated activation of an intrinsic mitochondrion-dependent pathway",
abstract = "Alveolar type II epithelial cells can regulate immune responses to sepsis-induced acute lung injury. Lipopolysaccharide (LPS), an outer membrane component of Gram-negative bacteria, can cause septic shock. This study was designed to evaluate the cytotoxic effects of LPS on human alveolar epithelial A549 cells and its possible molecular mechanisms. Exposure of A549 cells to LPS decreased cell viability in concentration- and time-dependent manners. In parallel, LPS concentration- and time-dependently induced apoptosis of A549 cells. Meanwhile, LPS only at a high concentration of 10 μg/ml caused mildly necrotic insults to A549 cells. In terms of the mechanism, exposure of A549 cells to LPS increased the levels of cellular nitric oxide and reactive oxygen species (ROS). Pretreatment with N-acetylcysteine (NAC), an antioxidant, significantly lowered LPS-caused enhancement of intracellular ROS in A549 cells and simultaneously attenuated the apoptotic insults. Sequentially, treatment of A549 cells with LPS caused significant decreases in the mitochondrial membrane potential and biosynthesis of adenosine triphosphate. In succession, LPS triggered the release of cytochrome c from the mitochondria to the cytoplasm. Activities of caspase-9 and caspase-6 were subsequently augmented following LPS administration. Consequently, exposure of A549 cells induced DNA fragmentation in a time-dependent manner. Pretreatment of A549 cells with NAC significantly ameliorated LPS-caused alterations in caspase-9 activation and DNA damage. Therefore, this study shows that LPS specifically induces apoptotic insults to human alveolar epithelial cells through ROS-mediated activation of the intrinsic mitochondrion-cytochrome c-caspase protease mechanism.",
keywords = "Alveolar epithelial cells, Apoptosis, Intrinsic mechanism, Lipopolysaccharide, Reactive oxygen species",
author = "Chuang, {Chi Yuan} and Chen, {Ta Liang} and Cherng, {Yih Giun} and Yu-Ting Tai and Chen, {Tyng Guey} and Chen, {Ruei Ming}",
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T1 - Lipopolysaccharide induces apoptotic insults to human alveolar epithelial A549 cells through reactive oxygen species-mediated activation of an intrinsic mitochondrion-dependent pathway

AU - Chuang, Chi Yuan

AU - Chen, Ta Liang

AU - Cherng, Yih Giun

AU - Tai, Yu-Ting

AU - Chen, Tyng Guey

AU - Chen, Ruei Ming

PY - 2011/3

Y1 - 2011/3

N2 - Alveolar type II epithelial cells can regulate immune responses to sepsis-induced acute lung injury. Lipopolysaccharide (LPS), an outer membrane component of Gram-negative bacteria, can cause septic shock. This study was designed to evaluate the cytotoxic effects of LPS on human alveolar epithelial A549 cells and its possible molecular mechanisms. Exposure of A549 cells to LPS decreased cell viability in concentration- and time-dependent manners. In parallel, LPS concentration- and time-dependently induced apoptosis of A549 cells. Meanwhile, LPS only at a high concentration of 10 μg/ml caused mildly necrotic insults to A549 cells. In terms of the mechanism, exposure of A549 cells to LPS increased the levels of cellular nitric oxide and reactive oxygen species (ROS). Pretreatment with N-acetylcysteine (NAC), an antioxidant, significantly lowered LPS-caused enhancement of intracellular ROS in A549 cells and simultaneously attenuated the apoptotic insults. Sequentially, treatment of A549 cells with LPS caused significant decreases in the mitochondrial membrane potential and biosynthesis of adenosine triphosphate. In succession, LPS triggered the release of cytochrome c from the mitochondria to the cytoplasm. Activities of caspase-9 and caspase-6 were subsequently augmented following LPS administration. Consequently, exposure of A549 cells induced DNA fragmentation in a time-dependent manner. Pretreatment of A549 cells with NAC significantly ameliorated LPS-caused alterations in caspase-9 activation and DNA damage. Therefore, this study shows that LPS specifically induces apoptotic insults to human alveolar epithelial cells through ROS-mediated activation of the intrinsic mitochondrion-cytochrome c-caspase protease mechanism.

AB - Alveolar type II epithelial cells can regulate immune responses to sepsis-induced acute lung injury. Lipopolysaccharide (LPS), an outer membrane component of Gram-negative bacteria, can cause septic shock. This study was designed to evaluate the cytotoxic effects of LPS on human alveolar epithelial A549 cells and its possible molecular mechanisms. Exposure of A549 cells to LPS decreased cell viability in concentration- and time-dependent manners. In parallel, LPS concentration- and time-dependently induced apoptosis of A549 cells. Meanwhile, LPS only at a high concentration of 10 μg/ml caused mildly necrotic insults to A549 cells. In terms of the mechanism, exposure of A549 cells to LPS increased the levels of cellular nitric oxide and reactive oxygen species (ROS). Pretreatment with N-acetylcysteine (NAC), an antioxidant, significantly lowered LPS-caused enhancement of intracellular ROS in A549 cells and simultaneously attenuated the apoptotic insults. Sequentially, treatment of A549 cells with LPS caused significant decreases in the mitochondrial membrane potential and biosynthesis of adenosine triphosphate. In succession, LPS triggered the release of cytochrome c from the mitochondria to the cytoplasm. Activities of caspase-9 and caspase-6 were subsequently augmented following LPS administration. Consequently, exposure of A549 cells induced DNA fragmentation in a time-dependent manner. Pretreatment of A549 cells with NAC significantly ameliorated LPS-caused alterations in caspase-9 activation and DNA damage. Therefore, this study shows that LPS specifically induces apoptotic insults to human alveolar epithelial cells through ROS-mediated activation of the intrinsic mitochondrion-cytochrome c-caspase protease mechanism.

KW - Alveolar epithelial cells

KW - Apoptosis

KW - Intrinsic mechanism

KW - Lipopolysaccharide

KW - Reactive oxygen species

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