Induction of Cell Death through Alteration of Oxidants and Antioxidants in Lung Epithelial Cells Exposed to High Energy Protons

Chronic obstructive pulmonary disease (COPD) is a chronic debilitating lung disease, characterized by progressive airway inflammation and lung structural cell death. Cigarette smoke is considered the most common risk factor of COPD pathogenesis. Understanding the molecular mechanisms of persistent inflammation and epithelial apoptosis induced by cigarette smoke would be extremely beneficial for improving the treatment and prevention of COPD. A histone methyl modifier, protein arginine N-methyltransferase 6 (PRMT6), is reported to alleviate cigarette smoke extract (CSE)-induced emphysema through inhibiting inflammation and cell apoptosis. However, few studies have focused on the modulation of PRMT6 in regulating inflammation and cell apoptosis. In this study, we showed that protein expression of PRMT6 was aberrantly decreased in the lung tissue of COPD patients and CSE-treated epithelial cells. FBXW17, a member of the Skp1-Cullin-F-box (SCF) family of E3 ubiquitin ligases, selectively bound to PRMT6 in nuclei to modulate its elimination in the proteasome system. Proteasome inhibitor or silencing of FBXW17 abrogated CSE-induced PRMT6 protein degradation. Furthermore, negative alteration of FBXW17/PRMT6 signaling lessened the proapoptotic and proinflammatory effects of CSE in lung epithelial cells. Our study, therefore, provides a potential therapeutic target against the airway inflammation and cell death in CS-induced COPD.

Download Full-text

3D printed lung on a chip device with a stretchable nanofibrous membrane for modeling ventilator induced lung injury

10.1101/2021.07.02.450873 ◽

2021 ◽

Author(s):

Sinem Tas ◽

Emil Rehnberg ◽

Deniz A. Bölükbaş ◽

Jason P. Beech ◽

Liora Nasi Kazado ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Lung Injury ◽

Mechanical Stretch ◽

Cell Types ◽

Lung Epithelial Cells ◽

Nanofibrous Membrane ◽

Ventilator Induced Lung Injury ◽

Lung Epithelial ◽

3D Printed

Mechanical ventilation is often required in patients with pulmonary disease to maintain adequate gas exchange. Despite improved knowledge regarding the risks of over ventilating the lung, ventilator induced lung injury (VILI) remains a major clinical problem due to inhomogeneities within the diseased lung itself as well as the need to increase pressure or volume of oxygen to the lung as a life-saving measure. VILI is characterized by increased physical forces exerted within the lung, which results in cell death, inflammation and long-term fibrotic remodeling. Animal models can be used to study VILI, but it is challenging to distinguish the contributions of individual cell types in such a setup. In vitro models, which allow for controlled stretching of specific lung cell types have emerged as a potential option, but these models and the membranes used in them are unable to recapitulate some key features of the lung such as the 3D nanofibrous structure of the alveolar basement membrane while also allowing for cells to be cultured at an air liquid interface (ALI) and undergo increased mechanical stretch that mimics VILI. Here we develop a lung on a chip device with a nanofibrous synthetic membrane to provide ALI conditions and controllable stretching, including injurious stretching mimicking VILI. The lung on a chip device consists of a thin (i.e. ~20 μm) stretchable poly(caprolactone) (PCL) nanofibrous membrane placed between two channels fabricated in polydimethylsiloxane (PDMS) using 3D printed molds. We demonstrate that this lung on a chip device can be used to induce mechanotrauma in lung epithelial cells due to cyclic pathophysiologic stretch (~25%) that mimics clinical VILI. Pathophysiologic stretch induces cell injury and subsequently cell death, which results in loss of the epithelial monolayer, a feature mimicking the early stages of VILI. We also validate the potential of our lung on a chip device to be used to explore cellular pathways known to be altered with mechanical stretch and show that pathophysiologic stretch of lung epithelial cells causes nuclear translocation of the mechanotransducers YAP/TAZ. In conclusion, we show that a breathable lung on a chip device with a nanofibrous membrane can be easily fabricated using 3D printing of the lung on a chip molds and that this model can be used to explore pathomechanisms in mechanically induced lung injury.

Download Full-text

Proliferation of Lung Epithelial Cells Is Regulated by the Mechanisms of Autophagy Upon Exposure of Soots

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.662597 ◽

2021 ◽

Vol 9 ◽

Author(s):

Rituraj Niranjan ◽

Kaushal Prasad Mishra ◽

Sachchida Nand Tripathi ◽

Ashwani Kumar Thakur

Keyword(s):

Cell Proliferation ◽

Cell Death ◽

Epithelial Cells ◽

Antioxidant Properties ◽

A549 Cells ◽

Beclin 1 ◽

Lung Epithelial Cells ◽

Akt Inhibitor ◽

Fullerene Soot ◽

Lung Epithelial

BackgroundSoots are known to cause many diseases in humans, but their underlying mechanisms of toxicity are still not known. Here, we report that soots induce cell proliferation of lung epithelial cells via modulating autophagy pathways.ResultsFullerene soot and diesel exhaust particles (DEP) induced cell proliferation of lung epithelial, A549 cells via distinct autophagic mechanisms and did not cause cell death. Exposure of fullerene soot protected the cell death of A549 cells, caused by hydrogen peroxide, and inhibited LPS-induced autophagy. Fullerene soot co-localized with the autophagic proteins and inhibited starvation-induced autophagy (downregulated ATG-5, beclin-1, p62, and LC3 expressions) independent of its antioxidant properties. Similarly, it decreased the expression profile of autophagic genes and upregulated the proliferation-responsive gene, Ki-67, in mice. We observed that expressions of fullerene soot-responsive genes (Beclin-1, ATG-5, and p62) were reverted by Akt Inhibitor X, indicating an important role of the Akt pathway. At an elemental level, we found that elemental carbon of fullerene soot may be converted into organic carbon, as measured by OCEC, which may point fullerene soot as a source of carbon. On the other hand, DEP upregulated the expressions of autophagy genes. Akt Inhibitor X did not attenuate DEP-induced cell proliferation and autophagic response. However, an autophagic inhibitor, chloroquine, and significantly inhibited DEP-induced cell proliferation.ConclusionIt can be said that distinct autophagic mechanisms are operational in cell proliferation of lung epithelial cells due to soots, which may be responsible for different diseases. Understanding the mechanism of these pathways provides some important targets, which can be utilized for the development of future therapeutics.

Download Full-text

TNF Family Cytokines Induce Distinct Cell Death Modalities in the A549 Human Lung Epithelial Cell Line when Administered in Combination with Ricin Toxin

Toxins ◽

10.3390/toxins11080450 ◽

2019 ◽

Vol 11 (8) ◽

pp. 450 ◽

Cited By ~ 5

Author(s):

Hodges ◽

Kempen ◽

McCaig ◽

Parker ◽

Mantis ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cell ◽

Epithelial Cells ◽

Human Lung ◽

Lung Epithelial Cells ◽

Lung Epithelial Cell ◽

Distinct Cell ◽

Tnf Α ◽

Lung Epithelial ◽

Human Lung Epithelial Cells

Ricin is a member of the ribosome-inactivating protein (RIP) family of toxins and is classified as a biothreat agent by the Centers for Disease Control and Prevention (CDC). Inhalation, the most potent route of toxicity, triggers an acute respiratory distress-like syndrome that coincides with near complete destruction of the lung epithelium. We previously demonstrated that the TNF-related apoptosis-inducing ligand (TRAIL; CD253) sensitizes human lung epithelial cells to ricin-induced death. Here, we report that ricin/TRAIL-mediated cell death occurs via apoptosis and involves caspases -3, -7, -8, and -9, but not caspase-6. In addition, we show that two other TNF family members, TNF-α and Fas ligand (FasL), also sensitize human lung epithelial cells to ricin-induced death. While ricin/TNF-α- and ricin/FasL-mediated killing of A549 cells was inhibited by the pan-caspase inhibitor, zVAD-fmk, evidence suggests that these pathways were not caspase-dependent apoptosis. We also ruled out necroptosis and pyroptosis. Rather, the combination of ricin plus TNF-α or FasL induced cathepsin-dependent cell death, as evidenced by the use of several pharmacologic inhibitors. We postulate that the effects of zVAD-fmk were due to the molecule’s known off-target effects on cathepsin activity. This work demonstrates that ricin-induced lung epithelial cell killing occurs by distinct cell death pathways dependent on the presence of different sensitizing cytokines, TRAIL, TNF-α, or FasL.

Download Full-text

MAPK pathways mediate hyperoxia-induced oncotic cell death in lung epithelial cells

Free Radical Biology and Medicine ◽

10.1016/s0891-5849(03)00494-5 ◽

2003 ◽

Vol 35 (8) ◽

pp. 978-993 ◽

Cited By ~ 53

Author(s):

John Romashko ◽

Stuart Horowitz ◽

William R Franek ◽

Tom Palaia ◽

Edmund J Miller ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Lung Epithelial Cells ◽

Mapk Pathways ◽

Lung Epithelial

Download Full-text

Paraquat-Induced Apoptotic Cell Death in Lung Epithelial Cells

Tuberculosis and Respiratory Diseases ◽

10.4046/trd.2006.61.4.366 ◽

2006 ◽

Vol 61 (4) ◽

pp. 366 ◽

Cited By ~ 1

Author(s):

Tak Ho Song ◽

Joo Yeon Yang ◽

In Kook Jeong ◽

Jae Seok Park ◽

Young Koo Jee ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Apoptotic Cell ◽

Apoptotic Cell Death ◽

Lung Epithelial Cells ◽

Lung Epithelial

Download Full-text

Mitochondrial localization of catalase provides optimal protection from H2O2-induced cell death in lung epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00296.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. L978-L986 ◽

Cited By ~ 28

Author(s):

Yuko Arita ◽

S. Hella Harkness ◽

Jeffrey A. Kazzaz ◽

Hshi-chi Koo ◽

Ansamma Joseph ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Cell Survival ◽

Cell Lines ◽

Mitochondrial Function ◽

Critical Role ◽

Lung Epithelial Cells ◽

Mitochondrial Localization ◽

Stable Cell Lines ◽

Lung Epithelial

Reactive oxygen species (ROS) can cause cell injury and death via mitochondrial-dependent pathways, and supplementation with antioxidants has been shown to ameliorate these processes. The c-Jun NH2-terminal kinase (JNK) pathway has been shown to play a critical role in ROS-induced cell death. To determine if targeting catalase (CAT) to the mitochondria provides better protection than cytosolic expression against H2O2-induced injury, the following two approaches were taken: 1) adenoviral-mediated transduction was performed using cytosolic (CCAT) or mitochondrial (MCAT) CAT cDNAs and 2) stable cell lines were generated overexpressing CAT in mitochondria ( n = 3). Cells were exposed to 250 μM H2O2, and cell survival, mitochondrial function, cytochrome c release, and JNK activity were analyzed. Although all viral transduced cells had a transient twofold increase in CAT activity, MCAT cells had significantly higher survival rates, the best mitochondrial function, and lowest JNK activity compared with CCAT and LacZ controls. The improved protection with MCAT was observed in primary type II lung epithelial cells and in transformed lung epithelial cells. In the three stable cell lines, cell survival directly correlated with extent of mitochondrial localization ( r = 0.60572, P < 0.05) and not overall CAT activity ( r = −0.45501, P < 0.05). Data indicate that targeting of antioxidants directly to the mitochondria is more effective in protecting lung epithelial cells against ROS-induced injury. This has important implications in antioxidant supplementation trials to prevent ROS-induced lung injury in critically ill patients.

Download Full-text