Mitochondrial complex I, aconitase, and succinate dehydrogenase during hypoxia-reoxygenation: modulation of enzyme activities by MnSOD

2003 ◽  
Vol 285 (1) ◽  
pp. L189-L198 ◽  
Author(s):  
Charles S. Powell ◽  
Robert M. Jackson
Keyword(s):  
Epithelial Cell ◽  
Succinate Dehydrogenase ◽  
Enzyme Activities ◽  
Complex I ◽  
Nadh Dehydrogenase ◽  
Alveolar Epithelial Cell ◽  
A549 Cells ◽  
Enzyme Inactivation ◽  
Hypoxia Reoxygenation

Both NADH dehydrogenase (complex I) and aconitase are inactivated partially in vitro by superoxide ([Formula: see text]) and other oxidants that cause loss of iron from enzyme cubane (4Fe-4S) centers. We tested whether hypoxia-reoxygenation (H-R) by itself would decrease lung epithelial cell NADH dehydrogenase, aconitase, and succinate dehydrogenase (SDH) activities and whether transfection with adenoviral vectors expressing MnSOD (Ad.MnSOD) would inhibit oxidative enzyme inactivation and thus confirm a mechanism involving [Formula: see text]. Human lung carcinoma cells with alveolar epithelial cell characteristics (A549 cells) were exposed to <1% O2-5% CO2(hypoxia) for 24 h followed by air-5% CO2for 24 h (reoxygenation). NADH dehydrogenase activity was assayed in submitochondrial particles; aconitase and SDH activities were measured in cell lysates. H-R significantly decreased NADH dehydrogenase, aconitase, and SDH activities. Ad.MnSOD increased mitochondrial MnSOD substantially and prevented the inhibitory effects of H-R on enzyme activities. Addition of α-ketoglutarate plus aspartate, but not succinate, to medium prevented cytotoxicity due to 2,3-dimethoxy-1,4-naphthoquinone. After hypoxia, cells displayed significantly increased dihydrorhodamine fluorescence, indicating increased mitochondrial oxidant production. Inhibition of NADH dehydrogenase, aconitase, and SDH activities during reoxygenation are due to excess [Formula: see text] produced in mitochondria, because enzyme inactivation can be prevented by overexpression of MnSOD.

Pseudomonas aeruginosapyocyanin directly oxidizes glutathione and decreases its levels in airway epithelial cells

2004 ◽  
Vol 287 (1) ◽  
pp. L94-L103 ◽  
Author(s):  
Yunxia Q. O'Malley ◽  
Krzysztof J. Reszka ◽  
Douglas R. Spitz ◽  
Gerene M. Denning ◽  
Bradley E. Britigan
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Culture Media ◽  
Alveolar Epithelial Cell ◽  
A549 Cells ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Alternative Source ◽  
Cell Functions

Production of pyocyanin enhances Pseudomonas aeruginosa virulence. Many of pyocyanin's in vitro and in vivo cytotoxic effects on human cells appear to result from its ability to redox cycle. Pyocyanin directly accepts electrons from NADH or NADPH with subsequent electron transfer to oxygen, generating reactive oxygen species. Reduced glutathione (GSH) is an important cellular antioxidant, and it contributes to the regulation of redox-sensitive signaling systems. Using the human bronchial epithelial (HBE) and the A549 human type II alveolar epithelial cell lines, we tested the hypothesis that pyocyanin can deplete airway epithelial cells of GSH. Incubation of both cell types with pyocyanin led to a concentration-dependent loss of cellular GSH (up to 50%) and an increase in oxidized GSH (GSSG) in the HBE, but not A549 cells, at 24 h. An increase in total GSH, mostly as GSSG, was detected in the culture media, suggesting export of GSH or GSSG from the pyocyanin-exposed cells. Loss of GSH could be due to pyocyanin-induced H2O2formation. However, overexpression of catalase only partially prevented the pyocyanin-mediated decline in cellular GSH. Cell-free electron paramagnetic resonance studies revealed that pyocyanin directly oxidizes GSH, forming pyocyanin free radical and O2−·. Pyocyanin oxidized other thiol-containing compounds, cysteine and N-acetyl-cysteine, but not methionine. Thus GSH may enhance pyocyanin-induced cytotoxicity by functioning as an alternative source of reducing equivalents for pyocyanin redox cycling. Pyocyanin-mediated alterations in cellular GSH may alter epithelial cell functions by modulating redox sensitive signaling events.

scholarly journals Tumor growth of neurofibromin-deficient cells is driven by decreased respiration and hampered by NAD+ and SIRT3

2021 ◽  
Author(s):  
Ionica Masgras ◽  
Giuseppe Cannino ◽  
Francesco Ciscato ◽  
Carlos Sanchez-Martin ◽  
Marco Pizzi ◽  
...  
Keyword(s):  
Succinate Dehydrogenase ◽  
Complex I ◽  
Nadh Dehydrogenase ◽  
Chain Complex ◽  
Respiratory Chain Complex ◽  
Succinate Dehydrogenase Activity ◽  
Nadh Ratio ◽  
Shed Light

Neurofibromin loss drives neoplastic growth and a rewiring of mitochondrial metabolism. Here, we report that neurofibromin ablation dampens expression and activity of NADH dehydrogenase, the respiratory chain complex I, in an ERK-dependent fashion. This provides cells with resistance to pro-oxidants targeting complex I and decreases both respiration and intracellular NAD+. Expression of the alternative NADH dehydrogenase NDI1 raises NAD+/NADH ratio, enhances the activity of the mitochondrial NAD+-dependent deacetylase SIRT3 and interferes with tumorigenicity in neurofibromin-deficient cells. This anti-neoplastic effect is mimicked both in vitro and in vivo by administration of NAD+ precursors or by rising expression of the NAD+ deacetylase SIRT3, and is synergistic with ablation of the mitochondrial chaperone TRAP1, which augments succinate dehydrogenase activity further contributing to block pro-neoplastic metabolic changes of these cells. These findings shed light on chemotherapeutic resistance and on bioenergetic adaptations of tumors lacking neurofibromin, linking complex I inhibition to mitochondrial NAD+/NADH unbalance and SIRT3 inhibition, as well as to down-regulation of succinate dehydrogenase. This metabolic rewiring could unveil attractive therapeutic targets for neoplasms related to neurofibromin loss.

Transforming growth factor-alpha enhances alveolar epithelial cell repair in a new in vitro model

1994 ◽  
Vol 267 (6) ◽  
pp. L728-L738 ◽  
Author(s):  
F. Kheradmand ◽  
H. G. Folkesson ◽  
L. Shum ◽  
R. Derynk ◽  
R. Pytela ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cell ◽  
Wound Repair ◽  
Wound Closure ◽  
Transforming Growth Factor ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial ◽  
Factor Alpha ◽  
Vitro Model

Alveolar epithelial type II cells are essential for regenerating an intact alveolar barrier after destruction of type I cells in vivo. The first objective of these experimental studies was to develop an in vitro model to quantify alveolar epithelial cell wound repair. The second objective was to investigate mechanisms of alveolar epithelial cell wound healing by studying the effects of serum and transforming growth factor-alpha (TGF-alpha) on wound closure. Primary cultures of rat alveolar type II cells were prepared by standard methods and grown to form confluent monolayers in 48 h. Then a wound was made by denuding an area (mean initial area of 2.1 +/- 0.6 mm2) of the monolayer. Re-epithelialization of the denuded area over time in the presence or absence of serum was measured using quantitative measurements from time-lapse video microscopy. The half time of wound healing was significantly enhanced in the presence of serum compared with serum-free conditions (2.4 +/- 0.2 vs. 17.4 +/- 0.8 h, P < 0.001). We then tested the hypothesis that TGF-alpha is an important growth factor for stimulating wound repair of alveolar epithelial cells. Exogenous addition of TGF-alpha in serum-free medium resulted in a significantly more rapid wound closure, and, furthermore, the addition of a monoclonal antibody to TGF-alpha in the presence of serum significantly decreased fourfold the rate of wound closure. Measurement of internuclear cell distance confirmed that both cell motility and cell spreading were responsible for closure of the wound. These data demonstrate that 1) the mechanisms of alveolar cell repair can be studied in vitro and that 2) TGF-alpha is a potent growth factor that enhances in vitro alveolar epithelial cell wound closure.

EXTRACELLULAR MATRIX-DRIVEN ALVEOLAR EPITHELIAL CELL DIFFERENTIATION IN VITRO

2005 ◽  
Vol 31 (5) ◽  
pp. 461-482 ◽  
Author(s):  
Colin E. Olsen ◽  
Brant E. Isakson ◽  
Gregory J. Seedorf ◽  
Richard L. Lubman ◽  
Scott Boitano
Keyword(s):  
Extracellular Matrix ◽  
Cell Differentiation ◽  
Epithelial Cell ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial ◽  
Epithelial Cell Differentiation

scholarly journals GED-0507 attenuates lung fibrosis by counteracting myofibroblast transdifferentiation in vivo and in vitro

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257281
Author(s):  
Silvia Speca ◽  
Caroline Dubuquoy ◽  
Christel Rousseaux ◽  
Philippe Chavatte ◽  
Pierre Desreumaux ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Pulmonary Fibrosis ◽  
Transforming Growth Factor ◽  
Alveolar Epithelial Cell ◽  
Lung Fibroblasts ◽  
Epithelial Cell Line ◽  
Mesenchymal Transition ◽  
Alveolar Epithelial ◽  
Ppar Γ

The development of more effective, better tolerated drug treatments for progressive pulmonary fibrosis (of which idiopathic pulmonary fibrosis is the most common and severe form) is a research priority. The peroxisome proliferator-activated receptor gamma (PPAR-γ) is a key regulator of inflammation and fibrosis and therefore represents a potential therapeutic target. However, the use of synthetic PPAR-γ agonists may be limited by their potentially severe adverse effects. In a mouse model of bleomycin (BLM)-induced pulmonary fibrosis, we have demonstrated that the non-racemic selective PPAR-γ modulator GED-0507 is able to reduce body weight loss, ameliorate clinical and histological features of pulmonary fibrosis, and increase survival rate without any safety concerns. Here, we focused on the biomolecular effects of GED-0507 on various inflammatory/fibrotic pathways. We demonstrated that preventive and therapeutic administration of GED-0507 reduced the BLM-induced mRNA expression of several markers of fibrosis, including transforming growth factor (TGF)-β, alpha-smooth muscle actin, collagen and fibronectin as well as epithelial-to-mesenchymal transition (EMT) and expression of mucin 5B. The beneficial effect of GED-0507 on pulmonary fibrosis was confirmed in vitro by its ability to control TGFβ-induced myofibroblast activation in the A549 human alveolar epithelial cell line, the MRC-5 lung fibroblast line, and primary human lung fibroblasts. Compared with the US Food and Drug Administration-approved antifibrotic drugs pirfenidone and nintedanib, GED-0507 displayed greater antifibrotic activity by controlling alveolar epithelial cell dysfunction, EMT, and extracellular matrix remodeling. In conclusion, GED-0507 demonstrated potent antifibrotic properties and might be a promising drug candidate for the treatment of pulmonary fibrosis.

scholarly journals Role of collagenase in mediating in vitro alveolar epithelial wound repair

1999 ◽  
Vol 112 (2) ◽  
pp. 243-252
Author(s):  
E. Planus ◽  
S. Galiacy ◽  
M. Matthay ◽  
V. Laurent ◽  
J. Gavrilovic ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Adhesion ◽  
Epithelial Cell ◽  
Type I Collagen ◽  
Alveolar Epithelial Cell ◽  
Cell Monolayer ◽  
Type I ◽  
Type Ii ◽  
Alveolar Epithelial

Type II pneumocytes are essential for repair of the injured alveolar epithelium. The effect of two MMP collagenases, MMP-1 and MMP-13 on alveolar epithelial repair was studied in vitro. The A549 alveolar epithelial cell line and primary rat alveolar epithelial cell cultures were used. Cell adhesion and cell migration were measured with and without exogenous MMP-1. Wound healing of a cell monolayer of rat alveolar epithelial cell after a mechanical injury was evaluated by time lapse video analysis. Cell adhesion on type I collagen, as well as cytoskeleton stiffness, was decreased in the presence of exogenous collagenases. A similar decrease was observed when cell adhesion was tested on collagen that was first incubated with MMP-1 (versus control on intact collagen). Cell migration on type I collagen was promoted by collagenases. Wound healing of an alveolar epithelial cell monolayer was enhanced in the presence of exogenous collagenases. Our results suggest that collagenases could modulate the repair process by decreasing cell adhesion and cell stiffness, and by increasing cell migration on type I collagen. Collagen degradation could modify cell adhesion sites and collagen degradation peptides could induce alveolar type II pneumocyte migration. New insights regarding alveolar epithelial cell migration are particularly relevant to investigate early events during alveolar epithelial repair following lung injury.

Lactobacilli intra-tracheal administration protects from Pseudomonas aeruginosa pulmonary infection in mice – a proof of concept

2019 ◽  
Vol 10 (8) ◽  
pp. 893-900 ◽  
Author(s):  
M.S. Fangous ◽  
Y. Alexandre ◽  
N. Hymery ◽  
S. Gouriou ◽  
D. Arzur ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Murine Model ◽  
Alveolar Epithelial Cell ◽  
A549 Cells ◽  
Respiratory Pathogen ◽  
Public Health Issue ◽  
Epithelial Cell Line ◽  
High Morbidity ◽  
Respiratory Pathogens

The spreading of antibiotic resistance is a major public health issue, which requires alternative treatments to antibiotics. Lactobacilli have shown abilities to prevent pneumonia in clinical studies when given by oral route, certainly through the gut-lung axis involvement. Rationally, respiratory administration of lactobacilli has been developed and studied in murine model, to prevent from respiratory pathogens. It allows a direct effect of probiotics into the respiratory system. To our knowledge, no study has ever focused on the effect of probiotic intra-respiratory administration to prevent from Pseudomonas aeruginosa (PA) pneumonia, a major respiratory pathogen associated with high morbidity rates. In this study, we evaluated the beneficial activity of three Lactobacillus strains (Lactobacillus fermentum K.C6.3.1E, Lactobacillus zeae Od.76, Lactobacillus paracasei ES.D.88) previously screened by ourselves and known to be particularly efficient in vitro in inhibiting PAO1 virulence factors. Cytotoxic assays in alveolar epithelial cell line A549 were performed, followed by the comparison of two lactobacilli prophylactic protocols (one or two administrations) by intra-tracheal administration in a C57BL/6 murine model of PA pneumonia. A549 cells viability was improved from 23 to 75% when lactobacilli were administered before PAO1 incubation, demonstrating a protective effect (P<0.001). A significant decrease of 2 log of PAO1 was observed 4 h after PAO1 instillation (3×106 cfu/mouse) in both groups receiving lactobacilli (9×106 cfu/mouse) compared to PAO1 group (P<0.05). One single prophylactic administration of lactobacilli significantly decreased the secretion by 50% in bronchoalveolar lavages of interleukin (IL)-6 and tumour necrosis factor-α compared to PAO1. No difference of secretion was observed for the IL-10 secretion, whatever the prophylactic study design. This is the first study highlighting that direct lung administration of Lactobacillus strains protect against PA pneumonia. Next step will be to decipher the mechanisms involved before developing this novel approach for human applications.

Cell cycle kinetics in the alveolar epithelium

1997 ◽  
Vol 272 (6) ◽  
pp. L1031-L1045 ◽  
Author(s):  
B. D. Uhal
Keyword(s):  
Epithelial Cell ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelium ◽  
Cell Loss ◽  
Type Ii ◽  
Alveolar Epithelial ◽  
Pathological Conditions ◽  
Type Ii Cell ◽  
The Relationship

The type II alveolar epithelial cell has important metabolic and biosynthetic functions but also serves as the stem cell of the alveolar epithelium. Much of the evidence underlying this premise was obtained before 1980 and provided the basis for a working model that has not been reconsidered for more than fifteen years. With the exceptions to be discussed below, little evidence has accumulated in the interim to suggest that the model requires significant alteration. Important questions remain unanswered, however, and some components of the model need to be supplemented, particularly in light of recent investigations that have provided insights not possible in earlier work. In particular, in vitro studies have suggested that the relationship between the parent type II cell and its progeny may not be as straightforward as originally thought. In addition, the rate of epithelial cell loss was recognized long ago to be an important factor in the regulation of this system, but its kinetics and mechanisms have received little attention. These and other unresolved issues are critical to our understanding of the homeostasis of the alveolar epithelium under normal and pathological conditions.

scholarly journals Inhibition of viral and bacterial trigger-stimulated prostaglandin E2 by a throat lozenge containing flurbiprofen: An in vitro study using a human respiratory epithelial cell line

2020 ◽  
Vol 8 ◽  
pp. 205031212096056
Author(s):  
Rob Lambkin-Williams ◽  
Alex Mann ◽  
Adrian Shephard
Keyword(s):  
Epithelial Cell ◽  
Sore Throat ◽  
A549 Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Epithelial Cell Line ◽  
Prostaglandin E ◽  
Suitable Model ◽  
Tracheal Epithelial ◽  
Anti Inflammatory

Objectives: Symptoms of sore throat result from oropharyngeal inflammation, for which prostaglandin E2 is a key mediator. Flurbiprofen is a non-steroidal anti-inflammatory that provides sore throat relief. The preliminary objective of this study was to develop an in vitro model for assessing prostaglandin E2 stimulation by viral and bacterial triggers. The primary objective was to investigate the effect of diluted flurbiprofen-containing lozenges on prostaglandin E2 concentrations in stimulated cells. Methods: Prostaglandin E2 production was stimulated in three epithelial cell lines (A549, HEp2, and clonetics bronchial/tracheal epithelial) with influenza A virus (4.5 log10 tissue culture infectious dose50/mL), or bacterial lipopolysaccharide (10µ g/mL) and peptidoglycan (3µ g/mL) and incubated overnight. Prostaglandin E2 levels were assessed by enzyme-linked immunosorbent assay up to 24 h after stimulation. The effect of flurbiprofen 8.75 mg lozenges (diluted to 0.44 mg/mL) on PGE2 production in stimulated cells was assessed in parallel; prior to viral/LPS/PEP stimulation of cells, 300 μL of test product or control was added and incubated for 30 s, 2 and 5 min (and 10 min for bacterial trigger). Prostaglandin E2 levels were measured following stimulation. Results: Viral and lipopolysaccharide/peptidoglycan infection did not consistently stimulate HEp2 cells and bronchial/tracheal epithelial cells to produce prostaglandin E2. Influenza virus, and lipopolysaccharide/peptidoglycan stimulated high prostaglandin E2 concentrations in A549: mean prostaglandin E2 concentration 106.48 pg/mL with viral stimulation vs 33.82 pg/mL for uninfected cells; 83.84 pg/mL with lipopolysaccharide/peptidoglycan vs 71.96 pg/mL for uninfected cells. Flurbiprofen produced significant reductions in virus-stimulated prostaglandin E2 vs stimulated untreated cells at 2 min (p = 0.03). Flurbiprofen produced significant reductions in lipopolysaccharide/peptidoglycan-stimulated prostaglandin E2 concentrations from 30 s (p = 0.02), and at 2, 5 and 10 min (all p < 0.005) vs stimulated untreated cells. Conclusions: A549 cells provide a suitable model for assessment of prostaglandin E2 stimulation by viral and bacterial triggers. Diluted flurbiprofen-containing lozenges demonstrated rapid anti-inflammatory activity in viral- and lipopolysaccharide/peptidoglycan-stimulated A549 cells.

Dual mechanism forMycobacterium tuberculosiscytotoxicity on lung epithelial cells

2012 ◽  
Vol 58 (7) ◽  
pp. 909-916 ◽  
Author(s):  
Jorge Castro-Garza ◽  
W. Edward Swords ◽  
Russell K. Karls ◽  
Frederick D. Quinn
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Neutralizing Antibodies ◽  
Cytotoxic Effect ◽  
Alveolar Epithelial Cell ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Lung Epithelial

Mycobacterium tuberculosis strains CDC1551 and Erdman were used to assess cytotoxicity in infected A549 human alveolar epithelial cell monolayers. Strain CDC1551 was found to induce qualitatively greater disruption of A549 monolayers than was strain Erdman, although total intracellular and cell-associated bacterial growth rates over the course of the infections were not significantly different. Cell-free culture supernatants from human monocytic cells infected with either of the 2 M. tuberculosis strains produced a cytotoxic effect on A549 cells, correlating with the amount of tumor necrosis factor alpha (TNF-α) released by the infected monocytes. The addition of TNF-α-neutralizing antibodies to the supernatants from infected monocyte cultures did prevent the induction of a cytotoxic effect on A549 cells overlaid with this mixture but did not prevent the death of epithelial cells when added prior to infection with M. tuberculosis bacilli. Thus, these data agree with previous observations that lung epithelial cells infected with M. tuberculosis bacilli are rapidly killed in vitro. In addition, the data indicate that some of the observed epithelial cell killing may be collateral damage; the result of TNF-α released from M. tuberculosis-infected monocytes.

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