scholarly journals Potential Toxicity of Polymyxins in Human Lung Epithelial Cells

2017 ◽  
Vol 61 (6) ◽  
Author(s):  
Maizbha U. Ahmed ◽  
Tony Velkov ◽  
Yu-Wei Lin ◽  
Bo Yun ◽  
Cameron J. Nowell ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Human Lung ◽  
A549 Cells ◽  
Polymyxin B ◽  
Lung Epithelial Cells ◽  
Time Dependent ◽  
Gram Negative ◽  
Lung Epithelial

ABSTRACT Inhaled polymyxins are of considerable utility in achieving optimal exposure in the respiratory tract for the treatment of lung infections caused by multidrug-resistant Gram-negative pathogens. Current inhaled polymyxin therapy is empirical, and often large doses are used that may lead to potential pulmonary adverse effects. This study aimed to investigate the effect of polymyxins on human lung epithelial (A549) cells. The viability of A549 cells was examined after treatment with polymyxins by flow cytometry. Activation of caspases 3, 8, and 9, expression of Fas ligand (FasL), loss of mitochondrial membrane potential, and mitochondrial oxidative stress induced by polymyxin B were evaluated. The concentration of polymyxin B required to induce 50% of maximal cell death was 1.74 mM (95% confidence interval, 1.60 to 1.90 mM). Colistin was at least 2-fold less toxic than polymyxin B, while colistimethate was nontoxic. With 2.0 mM polymyxin B, 30.6% ± 11.5% (mean ± standard deviation) of the cells were apoptotic at 8 h and this increased to 71.3% ± 3.72% at 24 h. Concentration- and time-dependent activation of caspases 3, 8, and 9 was evident, while the activation of caspase 9 was more dramatic. Furthermore, polymyxin B caused concentration- and time-dependent FasL expression, production of mitochondrial reactive oxygen species, and changes in mitochondrial membrane potential. This is the first study to demonstrate that both extrinsic death receptor and intrinsic mitochondrial pathways are involved in polymyxin-induced toxicity in A549 cells. This knowledge base is critical for the development of novel strategies for the safe and effective inhalation therapy of polymyxins against Gram-negative “superbugs.”

scholarly journals Polymyxins induced metabolic perturbations in human lung epithelial cells

2021 ◽  
Author(s):  
Maizbha U. Ahmed ◽  
Mohammad A. K. Azad ◽  
Mengyao Li ◽  
Darren J. Creek ◽  
Meiling Han ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Untreated Control ◽  
Human Lung ◽  
A549 Cells ◽  
Polymyxin B ◽  
Membrane Lipid ◽  
Lung Epithelial Cells ◽  
Reduced Form ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

Inhaled polymyxins are associated with toxicity in human lung epithelial cells involving multiple apoptotic pathways. However, the mechanism of polymyxin-induced pulmonary toxicity remains unclear. This study aimed to investigate polymyxin-induced metabolomic perturbations in human lung epithelial A549 cells. A549 cells were treated with 0.5 or 1.0 mM of polymyxin B or colistin for 1, 4, and 24 h. Cellular metabolites were analyzed using LC-MS/MS and significantly perturbed metabolites (log 2 fold change [FC]≥1, FDR≤0.2) and key pathways were identified relative to untreated control samples. At 1 and 4 h very few significant changes in metabolites were observed relative to the untreated control cells. At 24 h, taurine (log 2 FC = -1.34±0.64) and hypotaurine (log 2 FC = -1.20±0.27) were significantly decreased by 1.0 mM polymyxin B. The reduced form of glutathione (GSH) was significantly depleted by 1.0 mM of polymyxin B at 24 h (log 2 FC = -1.80±0.42). Conversely, oxidized glutathione (GSSG) was significantly increased by 1.0 mM of both polymyxin B (log 2 FC = 1.38±0.13 at 4 h and 2.09 ± 0.20 at 24 h) and colistin (log 2 FC = 1.33±0.24 at 24 h). L-carnitine was significantly decreased by 1.0 mM of both polymyxins at 24 h, as were several key metabolites involved in biosynthesis and degradation of choline and ethanolamine (log 2 FC≤-1); several phosphatidylserines were also increased (log 2 FC≥1). Polymyxins perturbed key metabolic pathways maintaining cellular redox balance, mitochondrial β-oxidation, and membrane lipid biogenesis. These mechanistic findings may assist in developing new pharmacokinetic/pharmacodynamic strategies to attenuate the pulmonary toxicities of inhaled polymyxins and the discovery of new-generation polymyxins.

scholarly journals Comparative Toxic Effects of Manufactured Nanoparticles and Atmospheric Particulate Matter in Human Lung Epithelial Cells

2020 ◽  
Vol 18 (1) ◽  
pp. 22
Author(s):  
Yun Wu ◽  
Mei Wang ◽  
Shaojuan Luo ◽  
Yunfeng Gu ◽  
Dongyang Nie ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Human Lung ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Atmospheric Particulate Matter ◽  
Toxic Effects ◽  
Ros Generation ◽  
Atmospheric Particulate ◽  
Significant Difference ◽  
Lung Epithelial

Although nanoparticles (NPs) have been used as simplified atmospheric particulate matter (PM) models, little experimental evidence is available to support such simulations. In this study, we comparatively assessed the toxic effects of PM and typical NPs (four carbonaceous NPs with different morphologies, metal NPs of Fe, Al, and Ti, as well as SiO2 NPs) on human lung epithelial A549 cells. The EC50 value of PM evaluated by cell viability assay was 148.7 μg/mL, closest to that of SiO2 NPs, between the values of carbonaceous NPs and metal NPs. All particles caused varying degrees of reactive oxygen species (ROS) generation and adenosine triphosphate (ATP) suppression. TiO2 NPs showed similar performance with PM in inducing ROS production (p < 0.05). Small variations between two carbonaceous NPs (graphene oxides and graphenes) and PM were also observed at 50 μg/mL. Similarly, there was no significant difference in ATP inhibition between carbonaceous NPs and PM, while markedly different effects were caused by SiO2 NP and TiO2 NP exposure. Our results indicated that carbonaceous NPs could be served as potential surrogates for urban PM. The identification of PM model may help us further explore the specific roles and mechanisms of various components in PM.

Ionizing radiation enhances matrix metalloproteinase-2 production in human lung epithelial cells

2001 ◽  
Vol 280 (1) ◽  
pp. L30-L38 ◽  
Author(s):  
Jun Araya ◽  
Muneharu Maruyama ◽  
Kazuhiko Sassa ◽  
Tadashi Fujita ◽  
Ryuji Hayashi ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Ionizing Radiation ◽  
Basement Membrane ◽  
Lung Injury ◽  
Human Lung ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Radiation Induced ◽  
Human Lung Epithelial Cells

Radiation pneumonitis is a major complication of radiation therapy. However, the detailed cellular mechanisms have not been clearly defined. Based on the recognition that basement membrane disruption occurs in acute lung injury and that matrix metalloproteinase (MMP)-2 can degrade type IV collagen, one of the major components of the basement membrane, we hypothesized that ionizing radiation would modulate MMP-2 production in human lung epithelial cells. To evaluate this, the modulation of MMP-2 with irradiation was investigated in normal human bronchial epithelial cells as well as in A549 cells. We measured the activity of MMP-2 in the conditioned medium with zymography and the MMP-2 mRNA level with RT-PCR. Both of these cells constitutively expressed 72-kDa gelatinolytic activity, corresponding to MMP-2, and exposure to radiation increased this activity. Consistent with the data of zymography, ionizing radiation increased the level of MMP-2 mRNA. This radiation-induced increase in MMP-2 expression was mediated via p53 because the p53 antisense oligonucleotide abolished the increase in MMP-2 activity as well as the accumulation of p53 after irradiation in A549 cells. These results indicate that MMP-2 expression by human lung epithelial cells is involved in radiation-induced lung injury.

Glutamine protects mitochondrial structure and function in oxygen toxicity

2001 ◽  
Vol 280 (4) ◽  
pp. L779-L791 ◽  
Author(s):  
Shama Ahmad ◽  
Carl W. White ◽  
Ling-Yi Chang ◽  
Barbara K. Schneider ◽  
Corrie B. Allen
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Tricarboxylic Acid Cycle ◽  
A549 Cells ◽  
Oxygen Toxicity ◽  
Cycle Enzyme ◽  
Glutamine Deprivation ◽  
And Function ◽  
Dose Dependent Increase

Glutamine is an important mitochondrial substrate implicated in the protection of cells from oxidant injury, but the mechanisms of its action are incompletely understood. Human pulmonary epithelial-like (A549) cells were exposed to 95% O2 for 4 days in the absence and presence of glutamine. Cell proliferation in normoxia was dependent on glutamine, and glutamine deprivation markedly accelerated cell death in hyperoxia. Glutamine significantly increased cellular ATP levels in normoxia and prevented the loss of ATP in hyperoxia seen in glutamine-deprived cells. Mitochondrial membrane potential as assessed by flow cytometry with chloromethyltetramethylrosamine was increased by glutamine in hyperoxia-exposed A549 cells, and a glutamine dose-dependent increase in mitochondrial membrane potential was detected. Glutamine-supplemented, hyperoxia-exposed cells had a higher O2 consumption rate and GSH content. Electron and fluorescence microscopy revealed that, in hyperoxia, glutamine protected cellular structures, especially mitochondria, from damage. In hyperoxia, activity of the tricarboxylic acid cycle enzyme α-ketoglutarate dehydrogenase was partially protected by its indirect substrate, glutamine, indicating a mechanism of mitochondrial protection.

Protective effect of the dimer of 16,16-diMePGB1 against KCN-induced mitochondrial failure in hepatocytes

1992 ◽  
Vol 263 (2) ◽  
pp. C405-C411 ◽  
Author(s):  
Y. Park ◽  
T. M. Devlin ◽  
D. P. Jones
Keyword(s):  
Membrane Potential ◽  
Protective Effect ◽  
Ion Transport ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Time Dependent ◽  
Dependent Manner ◽  
Protective Effects ◽  
Cellular Swelling

The dimer and trimer of 16,16-dimethyl-15-dehydroprostaglandin B1 (16,16-diMePGB1) previously have been shown to have protective effects on mitochondrial function. To examine the potential mechanisms involved in protection against mitochondrial failure, we have studied the effects of the dimer of 16,16-diMe-PGB1 (dicalciphor) on mitochondrial function in hepatocytes exposed to KCN. Addition of micromolar concentrations of dicalciphor provided substantial protection against KCN-induced toxicity in a concentration- and time-dependent manner. Dicalciphor, however, had no effect on total or mitochondrial ATP losses in KCN-treated cells. The dimer prevented the marked loss of mitochondrial membrane potential (delta psi) and delta pH that occurs as a result of KCN treatment and prevented KCN-induced loading of phosphate in mitochondria. Furthermore, the dimer of 16,16-diMePGB1 also prevented KCN-induced mitochondrial and cellular swelling. These results demonstrate that dicalciphor protects against KCN-induced damage and that this protection is associated with regulation of specific mitochondrial ion transport functions.

scholarly journals Role of Nucleolin in Human Parainfluenza Virus Type 3 Infection of Human Lung Epithelial Cells

2004 ◽  
Vol 78 (15) ◽  
pp. 8146-8158 ◽  
Author(s):  
Santanu Bose ◽  
Mausumi Basu ◽  
Amiya K. Banerjee
Keyword(s):  
Epithelial Cells ◽  
Cell Surface ◽  
Human Lung ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Parainfluenza Virus ◽  
Lung Epithelial ◽  
Human Parainfluenza Virus ◽  
Type 3 ◽  
Human Lung Epithelial Cells

ABSTRACT Human parainfluenza virus type 3 (HPIV-3) is an airborne pathogen that infects human lung epithelial cells from the apical (luminal) plasma membrane domain. In the present study, we have identified cell surface-expressed nucleolin as a cellular cofactor required for the efficient cellular entry of HPIV-3 into human lung epithelial A549 cells. Nucleolin was enriched on the apical cell surface domain of A549 cells, and HPIV-3 interacted with nucleolin during entry. The importance of nucleolin during HPIV-3 replication was borne out by the observation that HPIV-3 replication was significantly inhibited following (i) pretreatment of cells with antinucleolin antibodies and (ii) preincubation of HPIV-3 with purified nucleolin prior to its addition to the cells. Moreover, HPIV-3 cellular internalization and attachment assays performed in the presence of antinucleolin antibodies and purified nucleolin revealed the requirement of nucleolin during HPIV-3 internalization but not during attachment. Thus, these results suggest that nucleolin expressed on the surfaces of human lung epithelial A549 cells plays an important role during HPIV-3 cellular entry.

scholarly journals Carbon nanotube uptake changes the biomechanical properties of human lung epithelial cells in a time-dependent manner

2015 ◽  
Vol 3 (19) ◽  
pp. 3983-3992 ◽  
Author(s):  
Chenbo Dong ◽  
Reem Eldawud ◽  
Linda M. Sargent ◽  
Michael L. Kashon ◽  
David Lowry ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Exposure Duration ◽  
Human Lung ◽  
Biomechanical Properties ◽  
Engineered Nanomaterials ◽  
Lung Epithelial Cells ◽  
Time Dependent ◽  
Dependent Manner ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

The toxicity of engineered nanomaterials in biological systems depends on both the nanomaterial properties and the exposure duration.

Induction of proinflammatory cytokines in human lung epithelial cells during Rhodococcus equi infection

2013 ◽  
Vol 62 (8) ◽  
pp. 1144-1152 ◽  
Author(s):  
Sara Remuzgo-Martínez ◽  
Lilian Pilares-Ortega ◽  
Lorena Álvarez-Rodríguez ◽  
Maitane Aranzamendi-Zaldunbide ◽  
Daniel Padilla ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Lung ◽  
A549 Cells ◽  
Rhodococcus Equi ◽  
Airway Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Initial Contact ◽  
Structural Level ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

Rhodococcus equi is an opportunistic human pathogen associated with immunosuppressed people. While the interaction of R. equi with macrophages has been comprehensively studied, little is known about its interactions with non-phagocytic cells. Here, we characterized the entry process of this bacterium into human lung epithelial cells. The invasion is inhibited by nocodazole and wortmannin, suggesting that the phosphatidylinositol 3-kinase pathway and microtubule cytoskeleton are important for invasion. Pre-incubation of R. equi with a rabbit anti-R. equi polyclonal antiserum resulted in a dramatic reduction in invasion. Also, the invasion process as studied by immunofluorescence and scanning electron microscopy indicates that R. equi make initial contact with the microvilli of the A549 cells, and at the structural level, the entry process was observed to occur via a zipper-like mechanism. Infected lung epithelial cells upregulate the expression of cytokines IL-8 and IL-6 upon infection. The production of these pro-inflammatory cytokines was significantly enhanced in culture supernatants from cells infected with non-mucoid plasmid-less strains when compared with cells infected with mucoid strains. These results demonstrate that human airway epithelial cells produce pro-inflammatory mediators against R. equi isolates.

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