scholarly journals Cross-talk between LAM cells and fibroblasts may influence alveolar epithelial cell behavior in Lymphangioleiomyomatosis

2021 ◽  
Author(s):  
Debbie Clements ◽  
Suzanne Miller ◽  
Roya Babaei-Jadidi ◽  
Mike Adam ◽  
S. Steven Potter ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cross Talk ◽  
Ex Vivo ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial Cells ◽  
Dependent Manner ◽  
Epithelial Migration ◽  
Alveolar Epithelial

Lymphangioleiomyomatosis (LAM) is a female specific cystic lung disease in which TSC2 deficient LAM cells, LAM-Associated Fibroblasts (LAFs) and other cell types infiltrate the lungs. LAM lesions can be associated with type II alveolar epithelial cells (AT2 cells). We hypothesised that the behaviour of AT2 cells in LAM is influenced locally by LAFs. We tested this hypothesis in patient samples and in vitro. In human LAM lung, nodular AT2 cells show enhanced proliferation when compared to parenchymal AT2 cells, demonstrated by increased Ki67 expression. Further, nodular AT2 cells express proteins associated with epithelial activation in other disease states including Matrix Metalloproteinase 7, and Fibroblast Growth Factor 7 (FGF7). In vitro, LAF conditioned medium is mitogenic and positively chemotactic for epithelial cells, increases the rate of epithelial repair and protects against apoptosis. In vitro, LAM patient-derived TSC2 null cells cocultured with LAFs upregulate LAF expression of the epithelial chemokine and mitogen FGF7, which is a potential mediator of fibroblast-epithelial crosstalk, in an mTOR dependent manner. In a novel in vitro model of LAM, ex vivo cultured LAM lung-derived microtissues promote both epithelial migration and adhesion. Our findings suggest that AT2 cells in LAM display a proliferative, activated phenotype and that fibroblast accumulation following LAM cell infiltration into the parenchyma contributes to this change in AT2 cell behaviour. Fibroblast-derived FGF7 may contribute to the cross-talk between LAFs and hyperplastic epithelium in vivo, but does not appear to be the main driver of the effects of LAFs on epithelial cells in vitro.

scholarly journals TRIM72 is required for effective repair of alveolar epithelial cell wounding

2014 ◽  
Vol 307 (6) ◽  
pp. L449-L459 ◽  
Author(s):  
Seong Chul Kim ◽  
Thomas Kellett ◽  
Shaohua Wang ◽  
Miyuki Nishi ◽  
Nagaraja Nagre ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Molecular Mechanisms ◽  
Striated Muscle ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial Cells ◽  
Lung Cells ◽  
Alveolar Epithelial ◽  
High Tidal Volume Ventilation

The molecular mechanisms for lung cell repair are largely unknown. Previous studies identified tripartite motif protein 72 (TRIM72) from striated muscle and linked its function to tissue repair. In this study, we characterized TRIM72 expression in lung tissues and investigated the role of TRIM72 in repair of alveolar epithelial cells. In vivo injury of lung cells was introduced by high tidal volume ventilation, and repair-defective cells were labeled with postinjury administration of propidium iodide. Primary alveolar epithelial cells were isolated and membrane wounding and repair were labeled separately. Our results show that absence of TRIM72 increases susceptibility to deformation-induced lung injury whereas TRIM72 overexpression is protective. In vitro cell wounding assay revealed that TRIM72 protects alveolar epithelial cells through promoting repair rather than increasing resistance to injury. The repair function of TRIM72 in lung cells is further linked to caveolin 1. These data suggest an essential role for TRIM72 in repair of alveolar epithelial cells under plasma membrane stress failure.

Silica directly increases permeability of alveolar epithelial cells

1990 ◽  
Vol 68 (4) ◽  
pp. 1354-1359 ◽  
Author(s):  
R. K. Merchant ◽  
M. W. Peterson ◽  
G. W. Hunninghake
Keyword(s):  
Epithelial Cells ◽  
Cell Injury ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelium ◽  
Alveolar Epithelial Cells ◽  
Dependent Manner ◽  
Alveolar Epithelial ◽  
Lactate Dehydrogenase Release ◽  
Capillary Membrane

Alveolar epithelial cell injury and increased alveolar-capillary membrane permeability are important features of acute silicosis. To determine whether silica particles contribute directly to this increased permeability, we measured paracellular permeability of rat alveolar epithelium after exposure to silica, in vitro, using markers of the extracellular space. Silica (Minusil) markedly increased permeability in a dose- and time-dependent manner. This was not the result of cytolytic injury, because lactate dehydrogenase release from monolayers exposed to silica was not increased. Pretreatment of the silica with serum, charged dextrans, or aluminum sulfate blocked the increase in permeability. Scanning electron microscopy demonstrated adherence of the silica to the surface of the alveolar epithelial cells. Thus silica can directly increase permeability of alveolar epithelium.

scholarly journals C3 Promotes Clearance of Klebsiella pneumoniae by A549 Epithelial Cells

2004 ◽  
Vol 72 (3) ◽  
pp. 1767-1774 ◽  
Author(s):  
Beatriz de Astorza ◽  
Guadalupe Cortés ◽  
Catalina Crespí ◽  
Carles Saus ◽  
José María Rojo ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Klebsiella Pneumoniae ◽  
Alveolar Epithelial Cells ◽  
Clinical Isolates ◽  
Complement Components ◽  
Innate Defense ◽  
Alveolar Epithelial

ABSTRACT The airway epithelium represents a primary site for contact between microbes and their hosts. To assess the role of complement in this event, we studied the interaction between the A549 cell line derived from human alveolar epithelial cells and a major nosocomial pathogen, Klebsiella pneumoniae, in the presence of serum. In vitro, we found that C3 opsonization of poorly encapsulated K. pneumoniae clinical isolates and an unencapsulated mutant enhanced dramatically bacterial internalization by A549 epithelial cells compared to highly encapsulated clinical isolates. Local complement components (either present in the human bronchoalveolar lavage or produced by A549 epithelial cells) were sufficient to opsonize K. pneumoniae. CD46 could competitively inhibit the internalization of K. pneumoniae by the epithelial cells, suggesting that CD46 is a receptor for the binding of complement-opsonized K. pneumoniae to these cells. We observed that poorly encapsulated strains appeared into the alveolar epithelial cells in vivo but that (by contrast) they were completely avirulent in a mouse model of pneumonia compared to the highly encapsulated strains. Our results show that bacterial opsonization by complement enhances the internalization of the avirulent microorganisms by nonphagocytic cells such as A549 epithelial cells and allows an efficient innate defense.

scholarly journals Podoplanin interaction with caveolin-1 promotes tumour cell migration and invasion

2018 ◽  
Author(s):  
Luisa Pedro ◽  
Jacqueline D. Shields
Keyword(s):  
Tumour Cell ◽  
Surface Expression ◽  
Alveolar Epithelial Cells ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
Caveolin 1 ◽  
Alveolar Epithelial ◽  
Podoplanin Expression

AbstractPodoplanin, a highly O-glycosylated type-1 transmembrane glycoprotein, found in lymphatic endothelial cells, podocytes, alveolar epithelial cells and lymph node fibroblasts is also expressed by tumour cells, and is correlated with more aggressive disease. Despite numerous studies documenting podoplanin expression, the mechanisms underlying its tumour-promoting functions remain unclear. Using a murine melanoma cell line that endogenously expresses podoplanin, we demonstrate interactions with proteins necessary for cytoskeleton reorganization, adhesion and matrix degradation, and endocytosis/receptor recycling but also identify a novel interaction with caveolin-1. We generated a panel of podoplanin and caveolin-1 variants to determine the molecular interactions and functional consequences of these interactions. Complementary in vitro and in vivo systems confirmed the existence of a functional cooperation in which surface expression of both full length, signalling competent podoplanin and caveolin-1 are necessary to induce directional migration and invasion, which is executed via PAK1 and ERK1 pathways. Our findings establish that podoplanin signalling mediates the invasive properties of melanoma cells in a caveolin-1 dependent manner.Summary StatementThis manuscript describes a new interaction and functional cooperation between podoplanin and caveolin1 that drives tumour cell invasion into surrounding tissues.

scholarly journals Flagellin/TLR5 Stimulate Myeloid Progenitors to Enter Lung Tissue and to Locally Differentiate Into Macrophages

2021 ◽  
Vol 12 ◽  
Author(s):  
Xin Lei ◽  
Jara Palomero ◽  
Iris de Rink ◽  
Tom de Wit ◽  
Martijn van Baalen ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Low Frequency ◽  
Lavage Fluid ◽  
Lung Lavage ◽  
Alveolar Epithelial Cells ◽  
Mouse Bone Marrow ◽  
Alveolar Epithelial ◽  
Toll Like Receptor 5

Toll-like receptor 5 (TLR5) is the receptor of bacterial Flagellin. Reportedly, TLR5 engagement helps to combat infections, especially at mucosal sites, by evoking responses from epithelial cells and immune cells. Here we report that TLR5 is expressed on a previously defined bipotent progenitor of macrophages (MΦs) and osteoclasts (OCs) that resides in the mouse bone marrow (BM) and circulates at low frequency in the blood. In vitro, Flagellin promoted the generation of MΦs, but not OCs from this progenitor. In vivo, MΦ/OC progenitors were recruited from the blood into the lung upon intranasal inoculation of Flagellin, where they rapidly differentiated into MΦs. Recruitment of the MΦ/OC progenitors into the lung was likely promoted by the CCL2/CCR2 axis, since the progenitors expressed CCR2 and type 2 alveolar epithelial cells (AECs) produced CCL2 upon stimulation by Flagellin. Moreover, CCR2 blockade reduced migration of the MΦ/OC progenitors toward lung lavage fluid (LLF) from Flagellin-inoculated mice. Our study points to a novel role of the Flagellin/TLR5 axis in recruiting circulating MΦ/OC progenitors into infected tissue and stimulating these progenitors to locally differentiate into MΦs. The progenitor pathway to produce MΦs may act, next to monocyte recruitment, to fortify host protection against bacterial infection at mucosal sites.

Apoptosis and DNA damage in type 2 alveolar epithelial cells cultured from hyperoxic rats

1998 ◽  
Vol 274 (5) ◽  
pp. L714-L720 ◽  
Author(s):  
Sue Buckley ◽  
Lora Barsky ◽  
Barbara Driscoll ◽  
Kenneth Weinberg ◽  
Kathryn D. Anderson ◽  
...  
Keyword(s):  
Dna Damage ◽  
Epithelial Cells ◽  
Cellular Response ◽  
Ex Vivo ◽  
Keratinocyte Growth Factor ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Dna Laddering

Apoptosis is a genetically controlled cellular response to developmental stimuli and environmental insult that culminates in cell death. Sublethal hyperoxic injury in rodents is characterized by a complex but reproducible pattern of lung injury and repair during which the alveolar surface is damaged, denuded, and finally repopulated by type 2 alveolar epithelial cells (AEC2). Postulating that apoptosis might occur in AEC2 after hyperoxic injury, we looked for the hallmarks of apoptosis in AEC2 from hyperoxic rats. A pattern of increased DNA end labeling, DNA laddering, and induction of p53, p21, and Bax proteins, strongly suggestive of apoptosis, was seen in AEC2 cultured from hyperoxic rats when compared with control AEC2. In contrast, significant apoptosis was not detected in freshly isolated AEC2 from oxygen-treated rats. Thus the basal culture conditions appeared to be insufficient to ensure the ex vivo survival of AEC2 damaged in vivo. The oxygen-induced DNA strand breaks were blocked by the addition of 20 ng/ml of keratinocyte growth factor (KGF) to the culture medium from the time of plating and were partly inhibited by Matrigel or a soluble extract of Matrigel. KGF treatment resulted in a partial reduction in the expression of the p21, p53, and Bax proteins but had no effect on DNA laddering. We conclude that sublethal doses of oxygen in vivo cause damage to AEC2, resulting in apoptosis in ex vivo culture, and that KGF can reduce the oxygen-induced DNA damage. We speculate that KGF plays a role as a survival factor in AEC2 by limiting apoptosis in the lung after acute hyperoxic injury.

scholarly journals Pulmonary surfactant inhibition of nanoparticle uptake by alveolar epithelial cells

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Radiom ◽  
M. Sarkis ◽  
O. Brookes ◽  
E. K. Oikonomou ◽  
A. Baeza-Squiban ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Pulmonary Surfactant ◽  
Fluid Layer ◽  
Alveolar Epithelial Cell ◽  
Cell System ◽  
Engineered Nanoparticles ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Inhaled Nanoparticles

Abstract Pulmonary surfactant forms a sub-micrometer thick fluid layer that covers the surface of alveolar lumen and inhaled nanoparticles therefore come in to contact with surfactant prior to any interaction with epithelial cells. We investigate the role of the surfactant as a protective physical barrier by modeling the interactions using silica-Curosurf-alveolar epithelial cell system in vitro. Electron microscopy displays that the vesicles are preserved in the presence of nanoparticles while nanoparticle-lipid interaction leads to formation of mixed aggregates. Fluorescence microscopy reveals that the surfactant decreases the uptake of nanoparticles by up to two orders of magnitude in two models of alveolar epithelial cells, A549 and NCI-H441, irrespective of immersed culture on glass or air–liquid interface culture on transwell. Confocal microscopy corroborates the results by showing nanoparticle-lipid colocalization interacting with the cells. Our work thus supports the idea that pulmonary surfactant plays a protective role against inhaled nanoparticles. The effect of surfactant should therefore be considered in predictive assessment of nanoparticle toxicity or drug nanocarrier uptake. Models based on the one presented in this work may be used for preclinical tests with engineered nanoparticles.

scholarly journals Pneumocystis Pneumonia Increases the Susceptibility of Mice to Sublethal Hyperoxia

2003 ◽  
Vol 71 (10) ◽  
pp. 5970-5978 ◽  
Author(s):  
James M. Beck ◽  
Angela M. Preston ◽  
Steven E. Wilcoxen ◽  
Susan B. Morris ◽  
Eric S. White ◽  
...  
Keyword(s):  
T Cells ◽  
Epithelial Cell ◽  
Cell Injury ◽  
Alveolar Epithelial Cell ◽  
Pulmonary Inflammation ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Epithelial Cell Injury

ABSTRACT Patients with Pneumocystis pneumonia often develop respiratory failure after entry into medical care, and one mechanism for this deterioration may be increased alveolar epithelial cell injury. In vitro, we previously demonstrated that Pneumocystis is not cytotoxic for alveolar epithelial cells. In vivo, however, infection with Pneumocystis could increase susceptibility to injury by stressors that, alone, would be sublethal. We examined transient exposure to hyperoxia as a prototypical stress that does cause mortality in normal mice. Mice were depleted of CD4+ T cells and inoculated intratracheally with Pneumocystis. Control mice were depleted of CD4+ T cells but did not receive Pneumocystis. After 4 weeks, mice were maintained in normoxia, were exposed to hyperoxia for 4 days, or were exposed to hyperoxia for 4 days followed by return to normoxia. CD4-depleted mice with Pneumocystis pneumonia demonstrated significant mortality after transient exposure to hyperoxia, while all uninfected control mice survived this stress. We determined that organism burdens were not different. However, infected mice exposed to hyperoxia and then returned to normoxia demonstrated significant increases in inflammatory cell accumulation and lung cell apoptosis. We conclude that Pneumocystis pneumonia leads to increased mortality following a normally sublethal hyperoxic insult, accompanied by alveolar epithelial cell injury and increased pulmonary inflammation.

scholarly journals Role of Acinetobactin-Mediated Iron Acquisition Functions in the Interaction of Acinetobacter baumannii Strain ATCC 19606Twith Human Lung Epithelial Cells, Galleria mellonella Caterpillars, and Mice

2012 ◽  
Vol 80 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Jennifer A. Gaddy ◽  
Brock A. Arivett ◽  
Michael J. McConnell ◽  
Rafael López-Rojas ◽  
Jerónimo Pachón ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Acinetobacter Baumannii ◽  
Galleria Mellonella ◽  
Ex Vivo ◽  
Iron Acquisition ◽  
Alveolar Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Content Type ◽  
Alveolar Epithelial

Acinetobacter baumannii, which causes serious infections in immunocompromised patients, expresses high-affinity iron acquisition functions needed for growth under iron-limiting laboratory conditions. In this study, we determined that the initial interaction of the ATCC 19606Ttype strain with A549 human alveolar epithelial cells is independent of the production of BasD and BauA, proteins needed for acinetobactin biosynthesis and transport, respectively. In contrast, these proteins are required for this strain to persist within epithelial cells and cause their apoptotic death. Infection assays usingGalleria mellonellalarvae showed that impairment of acinetobactin biosynthesis and transport functions significantly reduces the ability of ATCC 19606Tcells to persist and kill this host, a defect that was corrected by adding inorganic iron to the inocula. The results obtained with theseex vivoandin vivoapproaches were validated using a mouse sepsis model, which showed that expression of the acinetobactin-mediated iron acquisition system is critical for ATCC 19606Tto establish an infection and kill this vertebrate host. These observations demonstrate that the virulence of the ATCC 19606Tstrain depends on the expression of a fully active acinetobactin-mediated system. Interestingly, the three models also showed that impairment of BasD production results in an intermediate virulence phenotype compared to those of the parental strain and the BauA mutant. This observation suggests that acinetobactin intermediates or precursors play a virulence role, although their contribution to iron acquisition is less relevant than that of mature acinetobactin.

scholarly journals Nanomaterials induce different levels of oxidative stress, depending on the used model system: Comparison of in vitro and in vivo effects

2020 ◽  
Author(s):  
Isabel Karkossa ◽  
Anne Bannuscher ◽  
Bryan Hellack ◽  
Wendel Wohlleben ◽  
Julie Laloy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Alveolar Macrophages ◽  
Model System ◽  
Alveolar Epithelial Cells ◽  
Model Systems ◽  
Alveolar Epithelial ◽  
Different Levels

Abstract Background The immense variety and constant development of nanomaterials (NMs) raise the demand for a facilitated risk assessment, for which knowledge on NMs mode of actions (MoAs) is required. For this purpose, a comprehensive data basis is of paramountcy that can be obtained using omics. Furthermore, the establishment of suitable in vitro test systems is indispensable to follow the 3R concept and to master the high number of NMs. In the present study, we aimed at comparing NM effects in vitro and in vivo using a multi-omics approach. We applied an integrated data evaluation strategy based on proteomics and metabolomics to four silica NMs and one titanium dioxide-based NM. For in vitro investigations, alveolar epithelial cells and alveolar macrophages were treated with different doses of NMs, and the results were compared to effects on rat lungs after short-term inhalations and instillations at varying doses with and without a recovery period.Results Since the production of reactive oxygen species (ROS) is described to be a critical biological effect of NMs, and enrichment analyses confirmed oxidative stress as a significant effect upon NM treatment in vitro in the present study, we focused on different levels of oxidative stress. Thus, we found opposite changes for proteins and metabolites that are related to the production of reduced glutathione in alveolar epithelial cells and alveolar macrophages, illustrating that NMs MoAs depend on the used model system. Interestingly, in vivo, pathways related to inflammation were affected to a greater extent than oxidative stress responses. Hence, the assignment of the observed effects to the levels of oxidative stress was different in vitro and in vivo as well. However, the overall classification of “active” and “passive” NMs was consistent in vitro and in vivo.Conclusions The consistent classification indicates both tested cell lines to be suitable for NM toxicity assessment even though the induced levels of oxidative stress strongly depend on the used model systems. Thus, the here presented results highlight that model systems need to be carefully revised to decipher the extent to which they can replace in vivo testing.

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