scholarly journals In VitroIntracellular Activity andIn VivoEfficacy of Modithromycin, a Novel Bicyclolide, againstLegionella pneumophila

2011 ◽  
Vol 55 (4) ◽  
pp. 1594-1597 ◽  
Author(s):  
Takafumi Sato ◽  
Kazuhiro Tateda ◽  
Soichiro Kimura ◽  
Yoshikazu Ishii ◽  
Keizo Yamaguchi
Keyword(s):  
Legionella Pneumophila ◽  
Alveolar Epithelial Cells ◽  
Intracellular Bacteria ◽  
Pulmonary Infections ◽  
Once Daily ◽  
Alveolar Epithelial ◽  
Bactericidal Activities ◽  
Human Alveolar Epithelial Cells

ABSTRACTThein vitroandin vivoactivities of modithromycin, a novel bicyclolide, againstLegionella pneumophilawere compared with those of telithromycin, clarithromycin, azithromycin, and levofloxacin. All the test agents decreased the intracellular growth of viableL. pneumophilabacteria over 96 h of incubation in both types of cells used, A/J mouse-derived macrophages and A549 human alveolar epithelial cells, at extracellular concentrations of 4× and 16× MIC, respectively. However, when the agents were removed from the medium after exposure for 2 h, regrowth of intracellular bacteria occurred in both cell systems when they were exposed to telithromycin, clarithromycin, and levofloxacin but not when they were exposed to modithromycin and azithromycin. Once-daily administration of modithromycin at a dose of 10 mg/kg of body weight for 5 days led to a significant decrease of intrapulmonary viableL. pneumophilabacteria in immunosuppressed A/J mice. The efficacy of modithromycin was superior to the efficacies of telithromycin and clarithromycin and comparable to the efficacies of azithromycin and levofloxacin. In addition, modithromycin and azithromycin inhibited the intrapulmonary regrowth of bacteria even at 72 h after the last treatment, but telithromycin and levofloxacin did not. These results suggested that modithromycin has longer-lasting cellular pharmacokinetic features like azithromycin. In conclusion, modithromycin, as well as azithromycin, has excellentin vitroandin vivobactericidal activities and persistent efficacy against intracellularL. pneumophila. Modithromycin should be a useful agent for treatment of pulmonary infections caused by this pathogen.

Zinc-dependent cytoadherence of Legionella pneumophila to human alveolar epithelial cells in vitro

2007 ◽  
Vol 43 (5-6) ◽  
pp. 234-242 ◽  
Author(s):  
Diaraf Farba Yaradou ◽  
Dominique Raze ◽  
Christophe Ginevra ◽  
Florence Ader ◽  
Anne Doléans-Jordheim ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Legionella Pneumophila ◽  
Alveolar Epithelial Cells ◽  
Alveolar Epithelial ◽  
Human Alveolar Epithelial Cells

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.

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.

Gene transfer of hepatocyte growth factor by electroporation reduces bleomycin-induced lung fibrosis

2007 ◽  
Vol 292 (2) ◽  
pp. L529-L536 ◽  
Author(s):  
Amiq Gazdhar ◽  
Patrick Fachinger ◽  
Coretta van Leer ◽  
Jaroslaw Pierog ◽  
Mathias Gugger ◽  
...  
Keyword(s):  
Growth Factor ◽  
Gene Transfer ◽  
Pulmonary Fibrosis ◽  
Wound Repair ◽  
Alveolar Epithelial Cells ◽  
Epithelial Repair ◽  
Alveolar Epithelial ◽  
Hepatocyte Growth

Abnormal alveolar wound repair contributes to the development of pulmonary fibrosis after lung injury. Hepatocyte growth factor (HGF) is a potent mitogenic factor for alveolar epithelial cells and may therefore improve alveolar epithelial repair in vitro and in vivo. We hypothesized that HGF could increase alveolar epithelial repair in vitro and improve pulmonary fibrosis in vivo. Alveolar wound repair in vitro was determined using an epithelial wound repair model with HGF-transfected A549 alveolar epithelial cells. Electroporation-mediated, nonviral gene transfer of HGF in vivo was performed 7 days after bleomycin-induced lung injury in the rat. Alveolar epithelial repair in vitro was increased after transfection of wounded epithelial monolayers with a plasmid encoding human HGF, pCikhHGF [human HGF (hHGF) gene expressed from the cytomegalovirus (CMV) immediate-early promoter and enhancer] compared with medium control. Electroporation-mediated in vivo HGF gene transfer using pCikhHGF 7 days after intratracheal bleomycin reduced pulmonary fibrosis as assessed by histology and hydroxyproline determination 14 days after bleomycin compared with controls treated with the same vector not containing the HGF sequence (pCik). Lung epithelial cell proliferation was increased and apoptosis reduced in hHGF-treated lungs compared with controls, suggesting increased alveolar epithelial repair in vivo. In addition, profibrotic transforming growth factor-β1 (TGF-β1) was decreased in hHGF-treated lungs, indicating an involvement of TGF-β1 in hHGF-induced reduction of lung fibrosis. In conclusion, electroporation-mediated gene transfer of hHGF decreases bleomycin-induced pulmonary fibrosis, possibly by increasing alveolar epithelial cell proliferation and reducing apoptosis, resulting in improved alveolar wound repair.

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.

scholarly journals Protective Effect of Remdesivir Against Pulmonary Fibrosis in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaohe Li ◽  
Rui Liu ◽  
Yunyao Cui ◽  
Jingjing Liang ◽  
Zhun Bi ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Antiviral Drug ◽  
Alveolar Epithelial Cells ◽  
Lung Damage ◽  
Lung Fibroblasts ◽  
Mesenchymal Transition ◽  
Alveolar Epithelial ◽  
Tgf Β1

Pulmonary fibrosis is a known sequela of severe or persistent lung damage. Existing clinical, imaging and autopsy studies have shown that the lungs exhibit a pathological pulmonary fibrosis phenotype after infection with coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pulmonary fibrosis may be one of the most serious sequelae associated with coronavirus disease 2019 (COVID-19). In this study, we aimed to examine the preventative effects of the antiviral drug remdesivir on pulmonary fibrosis. We used a mouse model of bleomycin-induced pulmonary fibrosis to evaluate the effects of remdesivir on pulmonary fibrosis in vivo and further explored the potential pharmacological mechanisms of remdesivir in lung fibroblasts and alveolar epithelial cells in vitro. The preventive remdesivir treatment was started on the day of bleomycin installation, and the results showed that remdesivir significantly alleviated bleomycin-induced collagen deposition and improved pulmonary function. In vitro experiments showed that remdesivir dose-dependently suppressed TGF-β1-induced lung fibroblast activation and improved TGF-β1-induced alveolar epithelial to mesenchymal transition. Our results indicate that remdesivir can preventatively alleviate the severity of pulmonary fibrosis and provide some reference for the prevention of pulmonary fibrosis in patients with COVID-19.

Sign in / Sign up

Export Citation Format

Share Document