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Sample records for alveolar epithelial repair

  1. TRIM72 is required for effective repair of alveolar epithelial cell wounding

    PubMed Central

    Kim, Seong Chul; Kellett, Thomas; Wang, Shaohua; Nishi, Miyuki; Nagre, Nagaraja; Zhou, Beiyun; Flodby, Per; Shilo, Konstantin; Ghadiali, Samir N.; Takeshima, Hiroshi; Hubmayr, Rolf D.

    2014-01-01

    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. PMID:25106429

  2. The role of purinergic signaling on deformation induced injury and repair responses of alveolar epithelial cells.

    PubMed

    Belete, Hewan A; Hubmayr, Rolf D; Wang, Shaohua; Singh, Raman-Deep

    2011-01-01

    Cell wounding is an important driver of the innate immune response of ventilator-injured lungs. We had previously shown that the majority of wounded alveolus resident cells repair and survive deformation induced insults. This is important insofar as wounded and repaired cells may contribute to injurious deformation responses commonly referred to as biotrauma. The central hypothesis of this communication states that extracellular adenosine-5' triphosphate (ATP) promotes the repair of wounded alveolus resident cells by a P2Y2-Receptor dependent mechanism. Using primary type 1 alveolar epithelial rat cell models subjected to micropuncture injury and/or deforming stress we show that 1) stretch causes a dose dependent increase in cell injury and ATP media concentrations; 2) enzymatic depletion of extracellular ATP reduces the probability of stretch induced wound repair; 3) enriching extracellular ATP concentrations facilitates wound repair; 4) purinergic effects on cell repair are mediated by ATP and not by one of its metabolites; and 5) ATP mediated cell salvage depends at least in part on P2Y2-R activation. While rescuing cells from wounding induced death may seem appealing, it is possible that survivors of membrane wounding become governors of a sustained pro-inflammatory state and thereby perpetuate and worsen organ function in the early stages of lung injury syndromes. Means to uncouple P2Y2-R mediated cytoprotection from P2Y2-R mediated inflammation and to test the preclinical efficacy of such an undertaking deserve to be explored. PMID:22087324

  3. Surface expression of CD74 by type II alveolar epithelial cells: a potential mechanism for macrophage migration inhibitory factor-induced epithelial repair.

    PubMed

    Marsh, Leigh M; Cakarova, Lidija; Kwapiszewska, Grazyna; von Wulffen, Werner; Herold, Susanne; Seeger, Werner; Lohmeyer, Juergen

    2009-03-01

    Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine involved in acute lung injury and other processes such as wound repair and tumor growth. MIF exerts pro-proliferative effects on a variety of cell types including monocytes/macrophages, B cells, and gastric epithelial cell lines through binding to the major histocompatibility complex type II-associated invariant chain, CD74. In acute lung injury, inflammatory damage of the alveolar epithelium leads to loss of type I alveolar epithelial cells (AEC-I), which are replaced by proliferation and differentiation of type II alveolar epithelial cells (AEC-II). In this study we have investigated the potential of MIF to contribute to alveolar repair by stimulating alveolar epithelial cell proliferation. We show that murine AEC-II, but not AEC-I, express high surface levels of CD74 in vivo. Culture of AEC-II in vitro resulted in decreased mRNA levels for CD74 and loss of surface CD74 expression, which correlated with a transition of AEC-II to an AEC-I-like phenotype. MIF stimulation of AEC-II induced rapid and prolonged phosphorylation of ERK1/2 and Akt, increased expression of cyclins D1 and E, as well as AEC-II proliferation. Corresponding MIF signaling and enhanced thymidine incorporation was observed after MIF stimulation of MLE-12 cells transfected to overexpress CD74. In contrast, MIF did not induce MAPK activation, gene transcription, or increased proliferation in differentiated AEC-I-like cells that lack CD74. These data suggest a previously unidentified role of MIF-CD74 interaction by inducing proliferation of AEC-II, which may contribute to alveolar repair. PMID:19136583

  4. Modeling Alveolar Epithelial Cell Behavior In Spatially Designed Hydrogel Microenvironments

    NASA Astrophysics Data System (ADS)

    Lewis, Katherine Jean Reeder

    The alveolar epithelium consists of two cell phenotypes, elongated alveolar type I cells (AT1) and rounded alveolar type II cells (ATII), and exists in a complex three-dimensional environment as a polarized cell layer attached to a thin basement membrane and enclosing a roughly spherical lumen. Closely surrounding the alveolar cysts are capillary endothelial cells as well as interstitial pulmonary fibroblasts. Many factors are thought to influence alveolar epithelial cell differentiation during lung development and wound repair, including physical and biochemical signals from the extracellular matrix (ECM), and paracrine signals from the surrounding mesenchyme. In particular, disrupted signaling between the alveolar epithelium and local fibroblasts has been implicated in the progression of several pulmonary diseases. However, given the complexity of alveolar tissue architecture and the multitude of signaling pathways involved, designing appropriate experimental platforms for this biological system has been difficult. In order to isolate key factors regulating cellular behavior, the researcher ideally should have control over biophysical properties of the ECM, as well as the ability to organize multiple cell types within the scaffold. This thesis aimed to develop a 3D synthetic hydrogel platform to control alveolar epithelial cyst formation, which could then be used to explore how extracellular cues influence cell behavior in a tissue-relevant cellular arrangement. To accomplish this, a poly(ethylene glycol) (PEG) hydrogel network containing enzymatically-degradable crosslinks and bioadhesive pendant peptides was employed as a base material for encapsulating primary alveolar epithelial cells. First, an array of microwells of various cross-sectional shapes was photopatterned into a PEG gel containing photo-labile crosslinks, and primary ATII cells were seeded into the wells to examine the role of geometric confinement on differentiation and multicellular arrangement

  5. Epithelial Notch signaling regulates lung alveolar morphogenesis and airway epithelial integrity.

    PubMed

    Tsao, Po-Nien; Matsuoka, Chisa; Wei, Shu-Chen; Sato, Atsuyasu; Sato, Susumu; Hasegawa, Koichi; Chen, Hung-Kuan; Ling, Thai-Yen; Mori, Munemasa; Cardoso, Wellington V; Morimoto, Mitsuru

    2016-07-19

    Abnormal enlargement of the alveolar spaces is a hallmark of conditions such as chronic obstructive pulmonary disease and bronchopulmonary dysplasia. Notch signaling is crucial for differentiation and regeneration and repair of the airway epithelium. However, how Notch influences the alveolar compartment and integrates this process with airway development remains little understood. Here we report a prominent role of Notch signaling in the epithelial-mesenchymal interactions that lead to alveolar formation in the developing lung. We found that alveolar type II cells are major sites of Notch2 activation and show by Notch2-specific epithelial deletion (Notch2(cNull)) a unique contribution of this receptor to alveologenesis. Epithelial Notch2 was required for type II cell induction of the PDGF-A ligand and subsequent paracrine activation of PDGF receptor-α signaling in alveolar myofibroblast progenitors. Moreover, Notch2 was crucial in maintaining the integrity of the epithelial and smooth muscle layers of the distal conducting airways. Our data suggest that epithelial Notch signaling regulates multiple aspects of postnatal development in the distal lung and may represent a potential target for intervention in pulmonary diseases. PMID:27364009

  6. Alveolar Type II Epithelial Cell Dysfunction in Rat Experimental Hepatopulmonary Syndrome (HPS)

    PubMed Central

    Yang, Wenli; Hu, Bingqian; Wu, Wei; Batra, Sachin; Blackburn, Michael R.; Alcorn, Joseph L.; Fallon, Michael B.; Zhang, Junlan

    2014-01-01

    The hepatopulmonary syndrome (HPS) develops when pulmonary vasodilatation leads to abnormal gas exchange. However, in human HPS, restrictive ventilatory defects are also observed supporting that the alveolar epithelial compartment may also be affected. Alveolar type II epithelial cells (AT2) play a critical role in maintaining the alveolar compartment by producing four surfactant proteins (SPs, SP-A, SP-B, SP-C and SP-D) which also facilitate alveolar repair following injury. However, no studies have evaluated the alveolar epithelial compartment in experimental HPS. In this study, we evaluated the alveolar epithelial compartment and particularly AT2 cells in experimental HPS induced by common bile duct ligation (CBDL). We found a significant reduction in pulmonary SP production associated with increased apoptosis in AT2 cells after CBDL relative to controls. Lung morphology showed decreased mean alveolar chord length and lung volumes in CBDL animals that were not seen in control models supporting a selective reduction of alveolar airspace. Furthermore, we found that administration of TNF-α, the bile acid, chenodeoxycholic acid, and FXR nuclear receptor activation (GW4064) induced apoptosis and impaired SP-B and SP-C production in alveolar epithelial cells in vitro. These results imply that AT2 cell dysfunction occurs in experimental HPS and is associated with alterations in the alveolar epithelial compartment. Our findings support a novel contributing mechanism in experimental HPS that may be relevant to humans and a potential therapeutic target. PMID:25419825

  7. Epithelial Notch signaling regulates lung alveolar morphogenesis and airway epithelial integrity

    PubMed Central

    Tsao, Po-Nien; Matsuoka, Chisa; Wei, Shu-Chen; Sato, Atsuyasu; Sato, Susumu; Hasegawa, Koichi; Chen, Hung-kuan; Ling, Thai-Yen; Mori, Munemasa; Cardoso, Wellington V.; Morimoto, Mitsuru

    2016-01-01

    Abnormal enlargement of the alveolar spaces is a hallmark of conditions such as chronic obstructive pulmonary disease and bronchopulmonary dysplasia. Notch signaling is crucial for differentiation and regeneration and repair of the airway epithelium. However, how Notch influences the alveolar compartment and integrates this process with airway development remains little understood. Here we report a prominent role of Notch signaling in the epithelial–mesenchymal interactions that lead to alveolar formation in the developing lung. We found that alveolar type II cells are major sites of Notch2 activation and show by Notch2-specific epithelial deletion (Notch2cNull) a unique contribution of this receptor to alveologenesis. Epithelial Notch2 was required for type II cell induction of the PDGF-A ligand and subsequent paracrine activation of PDGF receptor-α signaling in alveolar myofibroblast progenitors. Moreover, Notch2 was crucial in maintaining the integrity of the epithelial and smooth muscle layers of the distal conducting airways. Our data suggest that epithelial Notch signaling regulates multiple aspects of postnatal development in the distal lung and may represent a potential target for intervention in pulmonary diseases. PMID:27364009

  8. Alveolar epithelial type II cell: defender of the alveolus revisited

    PubMed Central

    Fehrenbach, Heinz

    2001-01-01

    In 1977, Mason and Williams developed the concept of the alveolar epithelial type II (AE2) cell as a defender of the alveolus. It is well known that AE2 cells synthesise, secrete, and recycle all components of the surfactant that regulates alveolar surface tension in mammalian lungs. AE2 cells influence extracellular surfactant transformation by regulating, for example, pH and [Ca2+] of the hypophase. AE2 cells play various roles in alveolar fluid balance, coagulation/fibrinolysis, and host defence. AE2 cells proliferate, differentiate into AE1 cells, and remove apoptotic AE2 cells by phagocytosis, thus contributing to epithelial repair. AE2 cells may act as immunoregulatory cells. AE2 cells interact with resident and mobile cells, either directly by membrane contact or indirectly via cytokines/growth factors and their receptors, thus representing an integrative unit within the alveolus. Although most data support the concept, the controversy about the character of hyperplastic AE2 cells, reported to synthesise profibrotic factors, proscribes drawing a definite conclusion today. PMID:11686863

  9. Review of secondary alveolar cleft repair

    PubMed Central

    Cho-Lee, Gui-Youn; García-Díez, Eloy-Miguel; Nunes, Richard-Agostinho; Martí-Pagès, Carles; Sieira-Gil, Ramón; Rivera-Baró, Alejandro

    2013-01-01

    Introduction: The alveolar cleft is a bony defect that is present in 75% of the patients with cleft lip and palate. Although secondary alveolar cleft repair is commonly accepted for these patients, nowadays, controversy still remains regarding the surgical technique, the timing of the surgery, the donor site, and whether the use of allogenic materials improve the outcomes. The purpose of the present review was to evaluate the protocol, the surgical technique and the outcomes in a large population of patients with alveolar clefts that underwent secondary alveolar cleft repair. Materials and Methods: A total of 109 procedures in 90 patients with alveolar cleft were identified retrospectively after institutional review board approval was obtained. The patients were treated at a single institution during a period of 10 years (2001-2011). Data were collected regarding demographics, type of cleft, success parameters of the procedure (oronasal fistulae closure, unification of the maxillary segments, eruption and support of anterior teeth, support to the base of the nose, normal ridge form for prosthetic rehabilitation), donor site morbidity, and complications. Pre- and postoperative radiological examination was performed by means of orthopantomogram and computed tomography (CT) scan. Results: The average patient age was 14.2 years (range 4–21.3 years). There were 4 right alveolar-lip clefts, 9 left alveolar-lip clefts, 3 bilateral alveolar-lip clefts, 18 right palate-lip clefts, 40 left palate-lip clefts and 16 bilateral palate-lip clefts. All the success parameters were favorable in 87 patients. Iliac crest bone grafts were employed in all cases. There were three bone graft losses. In three cases, allogenic materials used in a first surgery performed in other centers, underwent infection and lacked consolidation. They were removed and substituted by autogenous iliac crest bone graft. Conclusions: The use of autogenous iliac crest for secondary alveolar bone grafting

  10. Alveolar epithelial disintegrity in pulmonary fibrosis.

    PubMed

    Kulkarni, Tejaswini; de Andrade, Joao; Zhou, Yong; Luckhardt, Tracy; Thannickal, Victor J

    2016-08-01

    Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by progressive decline in lung function, resulting in significant morbidity and mortality. Current concepts of the pathogenesis of IPF primarily center on dysregulated epithelial cell repair and altered epithelial-mesenchymal communication and extracellular matrix deposition following chronic exposure to cigarette smoke or environmental toxins. In recent years, increasing attention has been directed toward the role of the intercellular junctional complex in determining the specific properties of epithelia in pulmonary diseases. Additionally, recent genomewide association studies suggest that specific genetic variants predictive of epithelial cell dysfunction may confer susceptibility to the development of sporadic idiopathic pulmonary fibrosis. A number of genetic disorders linked to pulmonary fibrosis and familial interstitial pneumonias are associated with loss of epithelial integrity. However, the potential links between extrapulmonary clinical syndromes associated with defects in epithelial cells and the development of pulmonary fibrosis are not well understood. Here, we report a case of hereditary mucoepithelial dysplasia that presented with pulmonary fibrosis and emphysema on high-resolution computed tomography. This case illustrates a more generalizable concept of epithelial disintegrity in the development of fibrotic lung diseases, which is explored in greater detail in this review article. PMID:27233996

  11. Lung epithelial cells modulate the inflammatory response of alveolar macrophages.

    PubMed

    Rubovitch, Vardit; Gershnabel, Shoham; Kalina, Moshe

    2007-12-01

    The goal of this study was to examine the effect of alveolar epithelial cells on inflammatory responses in macrophages. Lung epithelial cells (either rat RLE-6TN or human A549 cells) reduced LPS-induced NO production in alveolar macrophages (AM) in a contact-independent mechanism. The inhibitory effect of the epithelial cells was present already at the transcriptional level: LPS-induced inducible NO synthase (iNOS) expression was significantly smaller. Surfactant protein A (SP-A)-induced NO production by alveolar macrophages was also reduced in the presence of A549 cells, though, by a different kinetics. LPS-induced interleukin-6 (IL-6) production (another inflammatory pathway) by alveolar macrophages was also reduced in the presence of RLE-6TN cells. These data suggest a role for lung epithelial cells in the complicated modulation of inflammatory processes, and provide an insight into the mechanism underlying. PMID:17851743

  12. Alveolar Epithelial Dynamics in Post-pneumonectomy Lung Growth

    PubMed Central

    Chamoto, Kenji; Gibney, Barry C.; Ackermann, Maximilian; Lee, Grace S.; Konerding, Moritz A.; Tsuda, Akira; Mentzer, Steven J.

    2013-01-01

    The intimate anatomic and functional relationship between epithelial cells and endothelial cells within the alveolus suggests the likelihood of a coordinated response during post-pneumonectomy lung growth. To define the population dynamics and potential contribution of alveolar epithelial cells to alveolar angiogenesis, we studied alveolar Type II and Type I cells during the 21 days after pneumonectomy. Alveolar Type II cells were defined and isolated by flow cytometry using a CD45−, MHC class II+, phosphine+ phenotype. These phenotypically defined alveolar Type II cells demonstrated an increase in cell number after pneumonectomy; the increase in cell number preceded the increase in Type I (T1α+) cells. Using a parabiotic wild type/GFP pneumonectomy model, less than 3% of the Type II cells and 1% of the Type I cells were positive for GFP—a finding consistent with the absence of a blood-borne contribution to alveolar epithelial cells. The CD45−, MHC class II+, phosphine+ Type II cells demonstrated the active transcription of angiogenesis-related genes both before and after pneumonectomy. When the Type II cells on day 7 after pneumonectomy were compared to non-surgical controls, 10 genes demonstrated significantly increased expression (p<.05). In contrast to the normal adult Type II cells, there was notable expression of inflammation-associated genes (Ccl2, Cxcl2, Ifng) as well as genes associated with epithelial growth (Ereg, Lep). Together, the data suggest an active contribution of local alveolar Type II cells to alveolar growth. PMID:23408540

  13. Bacillus anthracis Lethal Toxin Reduces Human Alveolar Epithelial Barrier Function

    PubMed Central

    Langer, Marybeth; Duggan, Elizabeth Stewart; Booth, John Leland; Patel, Vineet Indrajit; Zander, Ryan A.; Silasi-Mansat, Robert; Ramani, Vijay; Veres, Tibor Zoltan; Prenzler, Frauke; Sewald, Katherina; Williams, Daniel M.; Coggeshall, Kenneth Mark; Awasthi, Shanjana; Lupu, Florea; Burian, Dennis; Ballard, Jimmy Dale; Braun, Armin

    2012-01-01

    The lung is the site of entry for Bacillus anthracis in inhalation anthrax, the deadliest form of the disease. Bacillus anthracis produces virulence toxins required for disease. Alveolar macrophages were considered the primary target of the Bacillus anthracis virulence factor lethal toxin because lethal toxin inhibits mouse macrophages through cleavage of MEK signaling pathway components, but we have reported that human alveolar macrophages are not a target of lethal toxin. Our current results suggest that, unlike human alveolar macrophages, the cells lining the respiratory units of the lung, alveolar epithelial cells, are a target of lethal toxin in humans. Alveolar epithelial cells expressed lethal toxin receptor protein, bound the protective antigen component of lethal toxin, and were subject to lethal-toxin-induced cleavage of multiple MEKs. These findings suggest that human alveolar epithelial cells are a target of Bacillus anthracis lethal toxin. Further, no reduction in alveolar epithelial cell viability was observed, but lethal toxin caused actin rearrangement and impaired desmosome formation, consistent with impaired barrier function as well as reduced surfactant production. Therefore, by compromising epithelial barrier function, lethal toxin may play a role in the pathogenesis of inhalation anthrax by facilitating the dissemination of Bacillus anthracis from the lung in early disease and promoting edema in late stages of the illness. PMID:23027535

  14. Regulation and repair of the alveolar-capillary barrier in acute lung injury.

    PubMed

    Bhattacharya, Jahar; Matthay, Michael A

    2013-01-01

    Considerable progress has been made in understanding the basic mechanisms that regulate fluid and protein exchange across the endothelial and epithelial barriers of the lung under both normal and pathological conditions. Clinically relevant lung injury occurs most commonly from severe viral and bacterial infections, aspiration syndromes, and severe shock. The mechanisms of lung injury have been identified in both experimental and clinical studies. Recovery from lung injury requires the reestablishment of an intact endothelial barrier and a functional alveolar epithelial barrier capable of secreting surfactant and removing alveolar edema fluid. Repair mechanisms include the participation of endogenous progenitor cells in strategically located niches in the lung. Novel treatment strategies include the possibility of cell-based therapy that may reduce the severity of lung injury and enhance lung repair. PMID:23398155

  15. N-acetylcysteine inhibits alveolar epithelial-mesenchymal transition

    PubMed Central

    Felton, V. M.; Borok, Z.

    2009-01-01

    The ability of transforming growth factor-β1 (TGF-β1) to induce epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AEC) in vitro and in vivo, together with the demonstration of EMT in biopsies of idiopathic pulmonary fibrosis (IPF) patients, suggests a role for TGF-β1-induced EMT in disease pathogenesis. We investigated the effects of N-acetylcysteine (NAC) on TGF-β1-induced EMT in a rat epithelial cell line (RLE-6TN) and in primary rat alveolar epithelial cells (AEC). RLE-6TN cells exposed to TGF-β1 for 5 days underwent EMT as evidenced by acquisition of a fibroblast-like morphology, downregulation of the epithelial-specific protein zonula occludens-1, and induction of the mesenchymal-specific proteins α-smooth muscle actin (α-SMA) and vimentin. These changes were inhibited by NAC, which also prevented Smad3 phosphorylation. Similarly, primary alveolar epithelial type II cells exposed to TGF-β1 also underwent EMT that was prevented by NAC. TGF-β1 decreased cellular GSH levels by 50–80%, whereas NAC restored them to ∼150% of those found in TGF-β1-treated cells. Treatment with glutathione monoethyl ester similarly prevented an increase in mesenchymal marker expression. Consistent with its role as an antioxidant and cellular redox stabilizer, NAC dramatically reduced intracellular reactive oxygen species production in the presence of TGF-β1. Finally, inhibition of intracellular ROS generation during TGF-β1 treatment prevented alveolar EMT, but treatment with H2O2 alone did not induce EMT. We conclude that NAC prevents EMT in AEC in vitro, at least in part through replenishment of intracellular GSH stores and limitation of TGF-β1-induced intracellular ROS generation. We speculate that beneficial effects of NAC on pulmonary function in IPF may be mediated by inhibitory effects on alveolar EMT. PMID:19648289

  16. N-acetylcysteine inhibits alveolar epithelial-mesenchymal transition.

    PubMed

    Felton, V M; Borok, Z; Willis, B C

    2009-11-01

    The ability of transforming growth factor-beta1 (TGF-beta1) to induce epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AEC) in vitro and in vivo, together with the demonstration of EMT in biopsies of idiopathic pulmonary fibrosis (IPF) patients, suggests a role for TGF-beta1-induced EMT in disease pathogenesis. We investigated the effects of N-acetylcysteine (NAC) on TGF-beta1-induced EMT in a rat epithelial cell line (RLE-6TN) and in primary rat alveolar epithelial cells (AEC). RLE-6TN cells exposed to TGF-beta1 for 5 days underwent EMT as evidenced by acquisition of a fibroblast-like morphology, downregulation of the epithelial-specific protein zonula occludens-1, and induction of the mesenchymal-specific proteins alpha-smooth muscle actin (alpha-SMA) and vimentin. These changes were inhibited by NAC, which also prevented Smad3 phosphorylation. Similarly, primary alveolar epithelial type II cells exposed to TGF-beta1 also underwent EMT that was prevented by NAC. TGF-beta1 decreased cellular GSH levels by 50-80%, whereas NAC restored them to approximately 150% of those found in TGF-beta1-treated cells. Treatment with glutathione monoethyl ester similarly prevented an increase in mesenchymal marker expression. Consistent with its role as an antioxidant and cellular redox stabilizer, NAC dramatically reduced intracellular reactive oxygen species production in the presence of TGF-beta1. Finally, inhibition of intracellular ROS generation during TGF-beta1 treatment prevented alveolar EMT, but treatment with H2O2 alone did not induce EMT. We conclude that NAC prevents EMT in AEC in vitro, at least in part through replenishment of intracellular GSH stores and limitation of TGF-beta1-induced intracellular ROS generation. We speculate that beneficial effects of NAC on pulmonary function in IPF may be mediated by inhibitory effects on alveolar EMT. PMID:19648289

  17. Alveolar epithelial stem and progenitor cells: emerging evidence for their role in lung regeneration.

    PubMed

    Hoffman, A M; Ingenito, E P

    2012-01-01

    Lung injuries that impact the alveolus, such as emphysema, pulmonary fibrosis, and acute lung injury, are costly and prevalent problems. Moreover, the extent of alveolar injury and impairment of gas exchange is strongly associated with prognosis and survival. Thus, mechanisms of repair and regeneration of the lung alveolar compartment have received mounting attention as newer approaches to the study of stem and progenitor cells in this region unfold. The role of type II alveolar epithelial as the sole source of type I (AECI) and II (AECII) alveolar epithelial cells following lung injury has been recently challenged; recently, investigators have described stemprogenitor cells that function like precursors to AECII either in vitro or in vivo, both in mice and humans. Techniques to explore selfrenewal and multipotency have been rigorously applied to these putative stem-progenitor cell populations and the data thus far is compelling. This review provides background to the study of alveolar regeneration with the aim to provide context to the recent discoveries of putative stem-progenitor cells that may contribute to this process. PMID:23016551

  18. Hyperoxia stimulates the transdifferentiation of type II alveolar epithelial cells in newborn rats.

    PubMed

    Hou, Ana; Fu, Jianhua; Yang, Haiping; Zhu, Yuting; Pan, Yuqing; Xu, Shuyan; Xue, Xindong

    2015-05-01

    Supplemental oxygen treatment in preterm infants may cause bronchopulmonary dysplasia (BPD), which is characterized by alveolar simplification and vascular disorganization. Despite type II alveolar epithelial cell (AEC II) damage being reported previously, we found no decrease in the AEC II-specific marker, surfactant protein C (SP-C), in the BPD model in our previous study. We thus speculated that AEC II injury is not a unique mechanism of BPD-related pulmonary epithelial repair dysfunction and that abnormal transdifferentiation can exist. Newborn rats were randomly assigned to model (85% oxygen inhalation) and control groups (room air inhalation). Expressions of AEC I (aquaporin 5, T1α) and AEC II markers (SP-C, SP-B) were detected at three levels: 1) in intact lung tissue, 2) in AEC II isolated from rats in the two groups, and 3) in AEC II isolated from newborn rats, which were further cultured under either hyperoxic or normoxic conditions. In the model group, increased AEC I was observed at both the tissue and cell level, and markedly increased transdifferentiation was observed by immunofluorescent double staining. Transmission electron microscopy revealed morphological changes in alveolar epithelium such as damaged AECs, a fused air-blood barrier structure, and opened tight junctions in the model group. These findings indicate that transdifferentiation of AECs is not suppressed but rather is increased under hyperoxic treatment by compensation; however, such repair during injury cannot offset pulmonary epithelial air exchange and barrier dysfunction caused by structural damage to AECs. PMID:25681436

  19. Cigarette smoke extract affects mitochondrial function in alveolar epithelial cells.

    PubMed

    Ballweg, Korbinian; Mutze, Kathrin; Königshoff, Melanie; Eickelberg, Oliver; Meiners, Silke

    2014-12-01

    Cigarette smoke is the main risk factor for chronic obstructive pulmonary disease (COPD). Exposure of cells to cigarette smoke induces an initial adaptive cellular stress response involving increased oxidative stress and induction of inflammatory signaling pathways. Exposure of mitochondria to cellular stress alters their fusion/fission dynamics. Whereas mild stress induces a prosurvival response termed stress-induced mitochondrial hyperfusion, severe stress results in mitochondrial fragmentation and mitophagy. In the present study, we analyzed the mitochondrial response to mild and nontoxic doses of cigarette smoke extract (CSE) in alveolar epithelial cells. We characterized mitochondrial morphology, expression of mitochondrial fusion and fission genes, markers of mitochondrial proteostasis, as well as mitochondrial functions such as membrane potential and oxygen consumption. Murine lung epithelial (MLE)12 and primary mouse alveolar epithelial cells revealed pronounced mitochondrial hyperfusion upon treatment with CSE, accompanied by increased expression of the mitochondrial fusion protein mitofusin 2 and increased metabolic activity. We did not observe any alterations in mitochondrial proteostasis, i.e., induction of the mitochondrial unfolded protein response or mitophagy. Therefore, our data indicate an adaptive prosurvival response of mitochondria of alveolar epithelial cells to nontoxic concentrations of CSE. A hyperfused mitochondrial network, however, renders the cell more vulnerable to additional stress, such as sustained cigarette smoke exposure. As such, cigarette smoke-induced mitochondrial hyperfusion, although part of a beneficial adaptive stress response in the first place, may contribute to the pathogenesis of COPD. PMID:25326581

  20. CHARACTERIZATION OF ALVEOLAR EPITHELIAL CELLS CULTURED IN SEMIPERMEABLE HOLLOW FIBERS

    PubMed Central

    Grek, Christina L.; Newton, Danforth A.; Qiu, Yonhzhi; Wen, Xuejun; Spyropoulos, Demetri D.; Baatz, John E.

    2012-01-01

    Cell culture methods commonly used to represent alveolar epithelial cells in vivo have lacked airflow, a 3-dimensional air-liquid interface, and dynamic stretching characteristics of native lung tissue—physiological parameters critical for normal phenotypic gene expression and cellular function. Here the authors report the development of a selectively semipermeable hollow fiber culture system that more accurately mimics the in vivo microenvironment experienced by mammalian distal airway cells than in conventional or standard air-liquid interface culture. Murine lung epithelial cells (MLE-15) were cultured within semipermeable polyurethane hollow fibers and introduced to controlled airflow through the microfiber interior. Under these conditions, MLE-15 cells formed confluent monolayers, demonstrated a cuboidal morphology, formed tight junctions, and produced and secreted surfactant proteins. Numerous lamellar bodies and microvilli were present in MLE-15 cells grown in hollow fiber culture. Conversely, these alveolar type II cell characteristics were reduced in MLE-15 cells cultured in conventional 2D static culture systems. These data support the hypothesis that MLE-15 cells grown within our microfiber culture system in the presence of airflow maintain the phenotypic characteristics of type II cells to a higher degree than those grown in standard in vitro cell culture models. Application of our novel model system may prove advantageous for future studies of specific gene and protein expression involving alveolar epithelial or bronchiolar epithelial cells. PMID:19263283

  1. A pure population of lung alveolar epithelial type II cells derived from human embryonic stem cells.

    PubMed

    Wang, Dachun; Haviland, David L; Burns, Alan R; Zsigmond, Eva; Wetsel, Rick A

    2007-03-13

    Alveolar epithelial type II (ATII) cells are small, cuboidal cells that constitute approximately 60% of the pulmonary alveolar epithelium. These cells are crucial for repair of the injured alveolus by differentiating into alveolar epithelial type I cells. ATII cells derived from human ES (hES) cells are a promising source of cells that could be used therapeutically to treat distal lung diseases. We have developed a reliable transfection and culture procedure, which facilitates, via genetic selection, the differentiation of hES cells into an essentially pure (>99%) population of ATII cells (hES-ATII). Purity, as well as biological features and morphological characteristics of normal ATII cells, was demonstrated for the hES-ATII cells, including lamellar body formation, expression of surfactant proteins A, B, and C, alpha-1-antitrypsin, and the cystic fibrosis transmembrane conductance receptor, as well as the synthesis and secretion of complement proteins C3 and C5. Collectively, these data document the successful generation of a pure population of ATII cells derived from hES cells, providing a practical source of ATII cells to explore in disease models their potential in the regeneration and repair of the injured alveolus and in the therapeutic treatment of genetic diseases affecting the lung. PMID:17360544

  2. Activation of Type II Cells into Regenerative Stem Cell Antigen-1+ Cells during Alveolar Repair

    PubMed Central

    Kumar, Varsha Suresh; Zhang, Wei; Rehman, Jalees; Malik, Asrar B.

    2015-01-01

    The alveolar epithelium is composed of two cell types: type I cells comprise 95% of the gas exchange surface area, whereas type II cells secrete surfactant, while retaining the ability to convert into type I cells to induce alveolar repair. Using lineage-tracing analyses in the mouse model of Pseudomonas aeruginosa–induced lung injury, we identified a population of stem cell antigen (Sca)-1–expressing type II cells with progenitor cell properties that mediate alveolar repair. These cells were shown to be distinct from previously reported Sca-1–expressing bronchioalveolar stem cells. Microarray and Wnt reporter studies showed that surfactant protein (Sp)-C+Sca-1+ cells expressed Wnt signaling pathway genes, and inhibiting Wnt/β-catenin signaling prevented the regenerative function of Sp-C+Sca-1+ cells in vitro. Thus, P. aeruginosa–mediated lung injury induces the generation of a Sca-1+ subset of type II cells. The progenitor phenotype of the Sp-C+Sca-1+ cells that mediates alveolar epithelial repair might involve Wnt signaling. PMID:25474582

  3. Targeting of the pulmonary capillary vascular niche promotes lung alveolar repair and ameliorates fibrosis

    PubMed Central

    Cao, Zhongwei; Lis, Raphael; Ginsberg, Michael; Chavez, Deebly; Shido, Koji; Rabbany, Sina Y.; Fong, Guo-Hua; Sakmar, Thomas P.; Rafii, Shahin; Ding, Bi-Sen

    2016-01-01

    Although the lung can undergo self-repair after injury, fibrosis in chronically injured or diseased lungs can occur at the expense of regeneration. Here we study how a hematopoietic-vascular niche regulates alveolar repair and lung fibrosis. Using intratracheal injection of bleomycin or hydrochloric acid in mice, we show that repetitive lung injury activates pulmonary capillary endothelial cells (PCECs) and perivascular macrophages, impeding alveolar repair and promoting fibrosis. Whereas the chemokine receptor CXCR7, expressed on PCECs, acts to prevent epithelial damage and ameliorate fibrosis after a single round of treatment with bleomycin or hydrochloric acid, repeated injury leads to suppression of CXCR7 expression and recruitment of vascular endothelial growth factor receptor 1 (VEGFR1)-expressing perivascular macrophages. This recruitment stimulates Wnt/β-catenin–dependent persistent upregulation of the Notch ligand Jagged1 (encoded by Jag1) in PCECs, which in turn stimulates exuberant Notch signaling in perivascular fibroblasts and enhances fibrosis. Administration of a CXCR7 agonist or PCEC-targeted Jag1 shRNA after lung injury promotes alveolar repair and reduces fibrosis. Thus, targeting of a maladaptbed hematopoietic-vascular niche, in which macrophages, PCECs and perivascular fibroblasts interact, may help to develop therapy to spur lung regeneration and alleviate fibrosis. PMID:26779814

  4. Targeting of the pulmonary capillary vascular niche promotes lung alveolar repair and ameliorates fibrosis.

    PubMed

    Cao, Zhongwei; Lis, Raphael; Ginsberg, Michael; Chavez, Deebly; Shido, Koji; Rabbany, Sina Y; Fong, Guo-Hua; Sakmar, Thomas P; Rafii, Shahin; Ding, Bi-Sen

    2016-02-01

    Although the lung can undergo self-repair after injury, fibrosis in chronically injured or diseased lungs can occur at the expense of regeneration. Here we study how a hematopoietic-vascular niche regulates alveolar repair and lung fibrosis. Using intratracheal injection of bleomycin or hydrochloric acid in mice, we show that repetitive lung injury activates pulmonary capillary endothelial cells (PCECs) and perivascular macrophages, impeding alveolar repair and promoting fibrosis. Whereas the chemokine receptor CXCR7, expressed on PCECs, acts to prevent epithelial damage and ameliorate fibrosis after a single round of treatment with bleomycin or hydrochloric acid, repeated injury leads to suppression of CXCR7 expression and recruitment of vascular endothelial growth factor receptor 1 (VEGFR1)-expressing perivascular macrophages. This recruitment stimulates Wnt/β-catenin-dependent persistent upregulation of the Notch ligand Jagged1 (encoded by Jag1) in PCECs, which in turn stimulates exuberant Notch signaling in perivascular fibroblasts and enhances fibrosis. Administration of a CXCR7 agonist or PCEC-targeted Jag1 shRNA after lung injury promotes alveolar repair and reduces fibrosis. Thus, targeting of a maladapted hematopoietic-vascular niche, in which macrophages, PCECs and perivascular fibroblasts interact, may help to develop therapy to spur lung regeneration and alleviate fibrosis. PMID:26779814

  5. Hyperoxia induces alveolar epithelial-to-mesenchymal cell transition

    PubMed Central

    Wang, Wenyi; Kato, Satomi; Colvocoresses-Dodds, Jennifer; Fifadara, Nimita H.; Gauthier, Theresa W.; Helms, My N.; Carlton, David P.; Brown, Lou Ann S.

    2013-01-01

    Myofibroblast accumulation is a pathological feature of lung diseases requiring oxygen therapy. One possible source for myofibroblasts is through the epithelial-to-mesenchymal transition (EMT) of alveolar epithelial cells (AEC). To study the effects of oxygen on alveolar EMT, we used RLE-6TN and ex vivo lung slices and found that hyperoxia (85% O2, H85) decreased epithelial proteins, presurfactant protein B (pre-SpB), pro-SpC, and lamellar protein by 50% and increased myofibroblast proteins, α-smooth muscle actin (α-SMA), and vimentin by over 200% (P < 0.05). In AEC freshly isolated from H85-treated rats, mRNA for pre-SpB and pro-SpC was diminished by ∼50% and α-SMA was increased by 100% (P < 0.05). Additionally, H85 increased H2O2 content, and H2O2 (25–50 μM) activated endogenous transforming growth factor-β1 (TGF-β1), as evident by H2DCFDA immunofluorescence and ELISA (P < 0.05). Both hyperoxia and H2O2 increased SMAD3 phosphorylation (260% of control, P < 0.05). Treating cultured cells with TGF-β1 inhibitors did not prevent H85-induced H2O2 production but did prevent H85-mediated α-SMA increases and E-cadherin downregulation. Finally, to determine the role of TGF-β1 in hyperoxia-induced EMT in vivo, we evaluated AEC from H85-treated rats and found that vimentin increased ∼10-fold (P < 0.05) and that this effect was prevented by intraperitoneal TGF-β1 inhibitor SB-431542. Additionally, SB-431542 treatment attenuated changes in alveolar histology caused by hyperoxia. Our studies indicate that hyperoxia promotes alveolar EMT through a mechanism that is dependent on activation of TGF-β1 signaling. PMID:24375795

  6. Hyperoxia induces alveolar epithelial-to-mesenchymal cell transition.

    PubMed

    Vyas-Read, Shilpa; Wang, Wenyi; Kato, Satomi; Colvocoresses-Dodds, Jennifer; Fifadara, Nimita H; Gauthier, Theresa W; Helms, My N; Carlton, David P; Brown, Lou Ann S

    2014-02-15

    Myofibroblast accumulation is a pathological feature of lung diseases requiring oxygen therapy. One possible source for myofibroblasts is through the epithelial-to-mesenchymal transition (EMT) of alveolar epithelial cells (AEC). To study the effects of oxygen on alveolar EMT, we used RLE-6TN and ex vivo lung slices and found that hyperoxia (85% O2, H85) decreased epithelial proteins, presurfactant protein B (pre-SpB), pro-SpC, and lamellar protein by 50% and increased myofibroblast proteins, α-smooth muscle actin (α-SMA), and vimentin by over 200% (P < 0.05). In AEC freshly isolated from H85-treated rats, mRNA for pre-SpB and pro-SpC was diminished by ∼50% and α-SMA was increased by 100% (P < 0.05). Additionally, H85 increased H2O2 content, and H2O2 (25-50 μM) activated endogenous transforming growth factor-β1 (TGF-β1), as evident by H2DCFDA immunofluorescence and ELISA (P < 0.05). Both hyperoxia and H2O2 increased SMAD3 phosphorylation (260% of control, P < 0.05). Treating cultured cells with TGF-β1 inhibitors did not prevent H85-induced H2O2 production but did prevent H85-mediated α-SMA increases and E-cadherin downregulation. Finally, to determine the role of TGF-β1 in hyperoxia-induced EMT in vivo, we evaluated AEC from H85-treated rats and found that vimentin increased ∼10-fold (P < 0.05) and that this effect was prevented by intraperitoneal TGF-β1 inhibitor SB-431542. Additionally, SB-431542 treatment attenuated changes in alveolar histology caused by hyperoxia. Our studies indicate that hyperoxia promotes alveolar EMT through a mechanism that is dependent on activation of TGF-β1 signaling. PMID:24375795

  7. Lung fibroblasts accelerate wound closure in human alveolar epithelial cells through hepatocyte growth factor/c-Met signaling

    PubMed Central

    Correll, Kelly; Schiel, John A.; Finigan, Jay H.; Prekeris, Rytis; Mason, Robert J.

    2014-01-01

    There are 190,600 cases of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) each year in the United States, and the incidence and mortality of ALI/ARDS increase dramatically with age. Patients with ALI/ARDS have alveolar epithelial injury, which may be worsened by high-pressure mechanical ventilation. Alveolar type II (ATII) cells are the progenitor cells for the alveolar epithelium and are required to reestablish the alveolar epithelium during the recovery process from ALI/ARDS. Lung fibroblasts (FBs) migrate and proliferate early after lung injury and likely are an important source of growth factors for epithelial repair. However, how lung FBs affect epithelial wound healing in the human adult lung has not been investigated in detail. Hepatocyte growth factor (HGF) is known to be released mainly from FBs and to stimulate both migration and proliferation of primary rat ATII cells. HGF is also increased in lung tissue, bronchoalveolar lavage fluid, and serum in patients with ALI/ARDS. Therefore, we hypothesized that HGF secreted by FBs would enhance wound closure in alveolar epithelial cells (AECs). Wound closure was measured using a scratch wound-healing assay in primary human AEC monolayers and in a coculture system with FBs. We found that wound closure was accelerated by FBs mainly through HGF/c-Met signaling. HGF also restored impaired wound healing in AECs from the elderly subjects and after exposure to cyclic stretch. We conclude that HGF is the critical factor released from FBs to close wounds in human AEC monolayers and suggest that HGF is a potential strategy for hastening alveolar repair in patients with ALI/ARDS. PMID:24748602

  8. Targeted Type 2 Alveolar Cell Depletion. A Dynamic Functional Model for Lung Injury Repair.

    PubMed

    Garcia, Orquidea; Hiatt, Michael J; Lundin, Amber; Lee, Jooeun; Reddy, Raghava; Navarro, Sonia; Kikuchi, Alex; Driscoll, Barbara

    2016-03-01

    Type 2 alveolar epithelial cells (AEC2) are regarded as the progenitor population of the alveolus responsible for injury repair and homeostatic maintenance. Depletion of this population is hypothesized to underlie various lung pathologies. Current models of lung injury rely on either uncontrolled, nonspecific destruction of alveolar epithelia or on targeted, nontitratable levels of fixed AEC2 ablation. We hypothesized that discrete levels of AEC2 ablation would trigger stereotypical and informative patterns of repair. To this end, we created a transgenic mouse model in which the surfactant protein-C promoter drives expression of a mutant SR39TK herpes simplex virus-1 thymidine kinase specifically in AEC2. Because of the sensitivity of SR39TK, low doses of ganciclovir can be administered to these animals to induce dose-dependent AEC2 depletion ranging from mild (50%) to lethal (82%) levels. We demonstrate that specific levels of AEC2 depletion cause altered expression patterns of apoptosis and repair proteins in surviving AEC2 as well as distinct changes in distal lung morphology, pulmonary function, collagen deposition, and expression of remodeling proteins in whole lung that persist for up to 60 days. We believe SPCTK mice demonstrate the utility of cell-specific expression of the SR39TK transgene for exerting fine control of target cell depletion. Our data demonstrate, for the first time, that specific levels of type 2 alveolar epithelial cell depletion produce characteristic injury repair outcomes. Most importantly, use of these mice will contribute to a better understanding of the role of AEC2 in the initiation of, and response to, lung injury. PMID:26203800

  9. Epithelial repair mechanisms in the lung.

    PubMed

    Crosby, Lynn M; Waters, Christopher M

    2010-06-01

    The recovery of an intact epithelium following lung injury is critical for restoration of lung homeostasis. The initial processes following injury include an acute inflammatory response, recruitment of immune cells, and epithelial cell spreading and migration upon an autologously secreted provisional matrix. Injury causes the release of factors that contribute to repair mechanisms including members of the epidermal growth factor and fibroblast growth factor families (TGF-alpha, KGF, HGF), chemokines (MCP-1), interleukins (IL-1beta, IL-2, IL-4, IL-13), and prostaglandins (PGE(2)), for example. These factors coordinate processes involving integrins, matrix materials (fibronectin, collagen, laminin), matrix metalloproteinases (MMP-1, MMP-7, MMP-9), focal adhesions, and cytoskeletal structures to promote cell spreading and migration. Several key signaling pathways are important in regulating these processes, including sonic hedgehog, Rho GTPases, MAP kinase pathways, STAT3, and Wnt. Changes in mechanical forces may also affect these pathways. Both localized and distal progenitor stem cells are recruited into the injured area, and proliferation and phenotypic differentiation of these cells leads to recovery of epithelial function. Persistent injury may contribute to the pathology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. For example, dysregulated repair processes involving TGF-beta and epithelial-mesenchymal transition may lead to fibrosis. This review focuses on the processes of epithelial restitution, the localization and role of epithelial progenitor stem cells, the initiating factors involved in repair, and the signaling pathways involved in these processes. PMID:20363851

  10. Retinoic acid promotes primary fetal alveolar epithelial type II cell proliferation and differentiation to alveolar epithelial type I cells.

    PubMed

    Gao, Rui-wei; Kong, Xiang-yong; Zhu, Xiao-xi; Zhu, Guo-qing; Ma, Jin-shuai; Liu, Xiu-xiang

    2015-05-01

    Retinoic acid (RA) plays an important role in lung development and maturation. Many stimuli can induce alveolar epithelial cell damage which will result in the injury of lung parenchyma. The aim of this study was to observe the effect of RA on the proliferation and differentiation of primary fetal alveolar epithelial type II cells (fAECIIs). Primary fAECIIs were isolated from fetal rats at 19 d of gestation and purified by a differential centrifugation and adhesion method. The cells were randomly divided into control (dimethyl sulfoxide, DMSO) and RA groups. Cell proliferation, viability, apoptosis, cycle, and expression of target protein were examined at 24, 48, and 72 h. We found that the proliferation and viability of cells in the RA-exposed group significantly increased compared with the DMSO control group. The proportion (%) of cells in the G2 and S phases in the RA group was significantly higher than that in control group cells. The proportion (%) of both early apoptotic cells and late apoptotic cells decreased significantly in cells exposed to RA compared with cells exposed to DMSO. RA significantly enhanced the expression of aquaporin 5 (AQP5). The expression level of pulmonary surfactant C (SPC) was elevated after cells were exposed to RA for 24 and 72 h but was inhibited when cells were exposed to RA for 48 h. These results suggest that RA promotes fAECII proliferation by improving cell viability, promoting S phase entry and inhibiting apoptosis and RA promotes fAECIIs differentiation to alveolar epithelial type I cells (AECIs). PMID:25515249

  11. Francisella tularensis replicates within alveolar type II epithelial cells in vitro and in vivo following inhalation.

    PubMed

    Hall, Joshua D; Craven, Robin R; Fuller, James R; Pickles, Raymond J; Kawula, Thomas H

    2007-02-01

    Francisella tularensis replicates in macrophages and dendritic cells, but interactions with other cell types have not been well described. F. tularensis LVS invaded and replicated within alveolar epithelial cell lines. Following intranasal inoculation of C57BL/6 mice, Francisella localized to the alveolus and replicated within alveolar type II epithelial cells. PMID:17088343

  12. Epithelial β1 integrin is required for lung branching morphogenesis and alveolarization.

    PubMed

    Plosa, Erin J; Young, Lisa R; Gulleman, Peter M; Polosukhin, Vasiliy V; Zaynagetdinov, Rinat; Benjamin, John T; Im, Amanda M; van der Meer, Riet; Gleaves, Linda A; Bulus, Nada; Han, Wei; Prince, Lawrence S; Blackwell, Timothy S; Zent, Roy

    2014-12-01

    Integrin-dependent interactions between cells and extracellular matrix regulate lung development; however, specific roles for β1-containing integrins in individual cell types, including epithelial cells, remain incompletely understood. In this study, the functional importance of β1 integrin in lung epithelium during mouse lung development was investigated by deleting the integrin from E10.5 onwards using surfactant protein C promoter-driven Cre. These mutant mice appeared normal at birth but failed to gain weight appropriately and died by 4 months of age with severe hypoxemia. Defects in airway branching morphogenesis in association with impaired epithelial cell adhesion and migration, as well as alveolarization defects and persistent macrophage-mediated inflammation were identified. Using an inducible system to delete β1 integrin after completion of airway branching, we showed that alveolarization defects, characterized by disrupted secondary septation, abnormal alveolar epithelial cell differentiation, excessive collagen I and elastin deposition, and hypercellularity of the mesenchyme occurred independently of airway branching defects. By depleting macrophages using liposomal clodronate, we found that alveolarization defects were secondary to persistent alveolar inflammation. β1 integrin-deficient alveolar epithelial cells produced excessive monocyte chemoattractant protein 1 and reactive oxygen species, suggesting a direct role for β1 integrin in regulating alveolar homeostasis. Taken together, these studies define distinct functions of epithelial β1 integrin during both early and late lung development that affect airway branching morphogenesis, epithelial cell differentiation, alveolar septation and regulation of alveolar homeostasis. PMID:25395457

  13. Alveolocapillary model system to study alveolar re-epithelialization

    SciTech Connect

    Willems, Coen H.M.P.; Zimmermann, Luc J.I.; Sanders, Patricia J.L.T.; Wagendorp, Margot; Kloosterboer, Nico; Cohen Tervaert, Jan Willem; Duimel, Hans J.Q.; Verheyen, Fons K.C.P.; Iwaarden, J. Freek van

    2013-01-01

    In the present study an in vitro bilayer model system of the pulmonary alveolocapillary barrier was established to investigate the role of the microvascular endothelium on re-epithelialization. The model system, confluent monolayer cultures on opposing sides of a porous membrane, consisted of a human microvascular endothelial cell line (HPMEC-ST1.6R) and an alveolar type II like cell line (A549), stably expressing EGFP and mCherry, respectively. These fluorescent proteins allowed the real time assessment of the integrity of the monolayers and the automated analysis of the wound healing process after a scratch injury. The HPMECs significantly attenuated the speed of re-epithelialization, which was associated with the proximity to the A549 layer. Examination of cross-sectional transmission electron micrographs of the model system revealed protrusions through the membrane pores and close contact between the A549 cells and the HPMECs. Immunohistochemical analysis showed that these close contacts consisted of heterocellular gap-, tight- and adherens-junctions. Additional analysis, using a fluorescent probe to assess gap-junctional communication, revealed that the HPMECs and A549 cells were able to exchange the fluorophore, which could be abrogated by disrupting the gap junctions using connexin mimetic peptides. These data suggest that the pulmonary microvascular endothelium may impact the re-epithelialization process. -- Highlights: ► Model system for vital imaging and high throughput screening. ► Microvascular endothelium influences re-epithelialization. ► A549 cells form protrusions through membrane to contact HPMEC. ► A549 cells and HPMECs form heterocellular tight-, gap- and adherens-junctions.

  14. Protein Expression Profile of Rat Type Two Alveolar Epithelial Cells During Hyperoxic Stress and Recovery

    NASA Astrophysics Data System (ADS)

    Bhargava, Maneesh

    Rationale: In rodent model systems, the sequential changes in lung morphology resulting from hyperoxic injury are well characterized, and are similar to changes in human acute respiratory distress syndrome (ARDS). In the injured lung, alveolar type two (AT2) epithelial cells play a critical role restoring the normal alveolar structure. Thus characterizing the changes in AT2 cells will provide insights into the mechanisms underpinning the recovery from lung injury. Methods: We applied an unbiased systems level proteomics approach to elucidate molecular mechanisms contributing to lung repair in a rat hyperoxic lung injury model. AT2 cells were isolated from rat lungs at predetermined intervals during hyperoxic injury and recovery. Protein expression profiles were determined by using iTRAQRTM with tandem mass spectrometry. Results: Of 959 distinct proteins identified, 183 significantly changed in abundance during the injury-recovery cycle. Gene Ontology enrichment analysis identified cell cycle, cell differentiation, cell metabolism, ion homeostasis, programmed cell death, ubiquitination, and cell migration to be significantly enriched by these proteins. Gene Set Enrichment Analysis of data acquired during lung repair revealed differential expression of gene sets that control multicellular organismal development, systems development, organ development, and chemical homeostasis. More detailed analysis identified activity in two regulatory pathways, JNK and miR 374. A Short Time-series Expression Miner (STEM) algorithm identified protein clusters with coherent changes during injury and repair. Conclusion: Coherent changes occur in the AT2 cell proteome in response to hyperoxic stress. These findings offer guidance regarding the specific molecular mechanisms governing repair of the injured lung.

  15. Alveolar Epithelial Cells Undergo Epithelial-to-Mesenchymal Transition in Response to Endoplasmic Reticulum Stress*

    PubMed Central

    Tanjore, Harikrishna; Cheng, Dong-Sheng; Degryse, Amber L.; Zoz, Donald F.; Abdolrasulnia, Rasul; Lawson, William E.; Blackwell, Timothy S.

    2011-01-01

    Expression of mutant surfactant protein C (SFTPC) results in endoplasmic reticulum (ER) stress in type II alveolar epithelial cells (AECs). AECs have been implicated as a source of lung fibroblasts via epithelial-to-mesenchymal transition (EMT); therefore, we investigated whether ER stress contributes to EMT as a possible mechanism for fibrotic remodeling. ER stress was induced by tunicamyin administration or stable expression of mutant (L188Q) SFTPC in type II AEC lines. Both tunicamycin treatment and mutant SFTPC expression induced ER stress and the unfolded protein response. With tunicamycin or mutant SFTPC expression, phase contrast imaging revealed a change to a fibroblast-like appearance. During ER stress, expression of epithelial markers E-cadherin and Zonula occludens-1 decreased while expression of mesenchymal markers S100A4 and α-smooth muscle actin increased. Following induction of ER stress, we found activation of a number of pathways, including MAPK, Smad, β-catenin, and Src kinase. Using specific inhibitors, the combination of a Smad2/3 inhibitor (SB431542) and a Src kinase inhibitor (PP2) blocked EMT with maintenance of epithelial appearance and epithelial marker expression. Similar results were noted with siRNA targeting Smad2 and Src kinase. Together, these studies reveal that induction of ER stress leads to EMT in lung epithelial cells, suggesting possible cross-talk between Smad and Src kinase pathways. Dissecting pathways involved in ER stress-induced EMT may lead to new treatment strategies to limit fibrosis. PMID:21757695

  16. Hyperoxia alters the mechanical properties of alveolar epithelial cells.

    PubMed

    Roan, Esra; Wilhelm, Kristina; Bada, Alex; Makena, Patrudu S; Gorantla, Vijay K; Sinclair, Scott E; Waters, Christopher M

    2012-06-15

    Patients with severe acute lung injury are frequently administered high concentrations of oxygen (>50%) during mechanical ventilation. Long-term exposure to high levels of oxygen can cause lung injury in the absence of mechanical ventilation, but the combination of the two accelerates and increases injury. Hyperoxia causes injury to cells through the generation of excessive reactive oxygen species. However, the precise mechanisms that lead to epithelial injury and the reasons for increased injury caused by mechanical ventilation are not well understood. We hypothesized that alveolar epithelial cells (AECs) may be more susceptible to injury caused by mechanical ventilation if hyperoxia alters the mechanical properties of the cells causing them to resist deformation. To test this hypothesis, we used atomic force microscopy in the indentation mode to measure the mechanical properties of cultured AECs. Exposure of AECs to hyperoxia for 24 to 48 h caused a significant increase in the elastic modulus (a measure of resistance to deformation) of both primary rat type II AECs and a cell line of mouse AECs (MLE-12). Hyperoxia also caused remodeling of both actin and microtubules. The increase in elastic modulus was blocked by treatment with cytochalasin D. Using finite element analysis, we showed that the increase in elastic modulus can lead to increased stress near the cell perimeter in the presence of stretch. We then demonstrated that cyclic stretch of hyperoxia-treated cells caused significant cell detachment. Our results suggest that exposure to hyperoxia causes structural remodeling of AECs that leads to decreased cell deformability. PMID:22467640

  17. Human alveolar epithelial type II cells in primary culture.

    PubMed

    Mao, Pu; Wu, Songling; Li, Jianchun; Fu, Wei; He, Weiqun; Liu, Xiaoqing; Slutsky, Arthur S; Zhang, Haibo; Li, Yimin

    2015-02-01

    Alveolar epithelial type II (AEII) cells are a key structure and defender in the lung but also are the targets in many lung diseases, including acute respiratory distress syndrome, ventilator-induced lung injury, and pulmonary fibrosis. We sought to establish an optimized method for high yielding and long maintenance of characteristics of primary human AEII cells to facilitate the investigation of the mechanisms of lung diseases at the cellular and molecular levels. Adult human peripheral normal lung tissues of oncologic patients undergoing lung resection were collected. The AEII cells were isolated and identified by the expression of pro-surfactant protein (SP)C, epithelial sodium channel (αENaC) and cytokeratin (CK)-8, the lamellar bodies specific for AEII cells, and confirmed by the histology using electron microscopy. The phenotype of AEII cells was characterized by the expression of surfactant proteins (SP-A, SP-B, SP-C, SP-D), CK-8, KL-6, αENaC, and aquaporin (AQP)-3, which was maintained over 20 days. The biological activity of the primary human AEII cells producing SP-C, cytokines, and intercellular adhesion molecule-1 was vigorous in response to stimulation with tumor necrosis factor-α. We have modified previous methods and optimized a method for isolation of high purity and long maintenance of the human AEII cell phenotype in primary culture. This method provides an important tool for studies aiming at elucidating the molecular mechanisms of lung diseases exclusively in AEII cells. PMID:25677546

  18. Human alveolar epithelial type II cells in primary culture

    PubMed Central

    Mao, Pu; Wu, Songling; Li, Jianchun; Fu, Wei; He, Weiqun; Liu, Xiaoqing; Slutsky, Arthur S; Zhang, Haibo; Li, Yimin

    2015-01-01

    Alveolar epithelial type II (AEII) cells are a key structure and defender in the lung but also are the targets in many lung diseases, including acute respiratory distress syndrome, ventilator-induced lung injury, and pulmonary fibrosis. We sought to establish an optimized method for high yielding and long maintenance of characteristics of primary human AEII cells to facilitate the investigation of the mechanisms of lung diseases at the cellular and molecular levels. Adult human peripheral normal lung tissues of oncologic patients undergoing lung resection were collected. The AEII cells were isolated and identified by the expression of pro-surfactant protein (SP)C, epithelial sodium channel (αENaC) and cytokeratin (CK)-8, the lamellar bodies specific for AEII cells, and confirmed by the histology using electron microscopy. The phenotype of AEII cells was characterized by the expression of surfactant proteins (SP-A, SP-B, SP-C, SP-D), CK-8, KL-6, αENaC, and aquaporin (AQP)-3, which was maintained over 20 days. The biological activity of the primary human AEII cells producing SP-C, cytokines, and intercellular adhesion molecule-1 was vigorous in response to stimulation with tumor necrosis factor-α. We have modified previous methods and optimized a method for isolation of high purity and long maintenance of the human AEII cell phenotype in primary culture. This method provides an important tool for studies aiming at elucidating the molecular mechanisms of lung diseases exclusively in AEII cells. PMID:25677546

  19. Potential Contribution of Type I Alveolar Epithelial Cells to Chronic Neonatal Lung Disease

    PubMed Central

    Rozycki, Henry J.

    2014-01-01

    The alveolar surface is covered by large flat Type I cells (alveolar epithelial cells 1, AEC1). The normal physiological function of AEC1s involves gas exchange, based on their location in approximation to the capillary endothelium and their thinness, and in ion and water flux, as shown by the presence of solute active transport proteins, water channels, and impermeable tight junctions between cells. With the recent ability to produce relatively pure cultures of AEC1 cells, new functions have been described. These may be relevant to lung injury, repair, and the abnormal development that characterizes bronchopulmonary dysplasia (BPD). To hypothesize a potential role for AEC1 in the development of lung injury and abnormal repair/development in premature lungs, evidence is presented for their presence in the developing lung, how their source may not be the Type II cell (AEC2) as has been assumed for 40 years, and how the cell can be damaged by same type of stressors as those which lead to BPD. Recent work shows that the cells are part of the innate immune response, capable of producing pro-inflammatory mediators, which could contribute to the increase in inflammation seen in early BPD. One of the receptors found exclusively on AEC1 cells in the lung, called RAGE, may also have a role in increased inflammation and alveolar simplification. While the current evidence for AEC1 involvement in BPD is circumstantial and limited at present, the accumulating data supports several hypotheses and questions regarding potential differences in the behavior of AEC1 cells from newborn and premature lung compared with the adult lung. PMID:24904906

  20. CXCR4 regulates migration of lung alveolar epithelial cells through activation of Rac1 and matrix metalloproteinase-2

    PubMed Central

    Ghosh, Manik C.; Makena, Patrudu S.; Gorantla, Vijay; Sinclair, Scott E.

    2012-01-01

    Restoration of the epithelial barrier following acute lung injury is critical for recovery of lung homeostasis. After injury, alveolar type II epithelial (ATII) cells spread and migrate to cover the denuded surface and, eventually, proliferate and differentiate into type I cells. The chemokine CXCL12, also known as stromal cell-derived factor 1α, has well-recognized roles in organogenesis, hematopoiesis, and immune responses through its binding to the chemokine receptor CXCR4. While CXCL12/CXCR4 signaling is known to be important in immune cell migration, the role of this chemokine-receptor interaction has not been studied in alveolar epithelial repair mechanisms. In this study, we demonstrated that secretion of CXCL12 was increased in the bronchoalveolar lavage of rats ventilated with an injurious tidal volume (25 ml/kg). We also found that CXCL12 secretion was increased by primary rat ATII cells and a mouse alveolar epithelial (MLE12) cell line following scratch wounding and that both types of cells express CXCR4. CXCL12 significantly increased ATII cell migration in a scratch-wound assay. When we treated cells with a specific antagonist for CXCR4, AMD-3100, cell migration was significantly inhibited. Knockdown of CXCR4 by short hairpin RNA (shRNA) caused decreased cell migration compared with cells expressing a nonspecific shRNA. Treatment with AMD-3100 decreased matrix metalloproteinase-14 expression, increased tissue inhibitor of metalloproteinase-3 expression, decreased matrix metalloproteinase-2 activity, and prevented CXCL12-induced Rac1 activation. Similar results were obtained with shRNA knockdown of CXCR4. These findings may help identify a therapeutic target for augmenting epithelial repair following acute lung injury. PMID:22345572

  1. Simultaneous Exposure to Multiple Air Pollutants Influences Alveolar Epithelial Cell Ion Transport

    EPA Science Inventory

    Purpose. Air pollution sources generally release multiple pollutants simultaneously and yet, research has historically focused on the source-to-health linkages of individual air pollutants. We recently showed that exposure of alveolar epithelial cells to a combination of particul...

  2. Isolation and Culture of Alveolar Epithelial Type I and Type II Cells from Rat Lungs

    PubMed Central

    Gonzalez, Robert F.; Dobbs, Leland G.

    2014-01-01

    The pulmonary alveolar epithelium, comprised of alveolar Type I (TI) and Type II (TII) cells, covers more than 99% of the internal surface area of the lungs. The study of isolated and cultured alveolar epithelial TI and TII cells has provided a large amount of information about the functions of both cell types. This chapter provides information about methods for isolating and culturing both of these cell types from rat lungs. PMID:23097106

  3. Association of ICAM-1 with the cytoskeleton in rat alveolar epithelial cells in primary culture.

    PubMed

    Barton, W W; Wilcoxen, S E; Christensen, P J; Paine, R

    1996-11-01

    Intercellular adhesion molecule-1 ICAM-1) is a transmembrane adhesion protein that is expressed constitutively on the apical surface of type I cells in vivo and on type II cells in vitro as they spread in culture, assuming type I cell-like characteristics. To investigate the possible interaction of ICAM-1 with the alveolar epithelial cell cytoskeleton, rat type II cells in primary culture were extracted with nonionic detergent, and residual ICAM-1 associated with the cytoskeletal remnants was determined using immunofluorescence microscopy, immunoprecipitation, and cell-based enzyme-linked immunosorbent assay. A large fraction of alveolar epithelial cell ICAM-1 remained associated with the cytoskeleton after detergent extraction, whereas two other transmembrane molecules, transferrin receptor and class II major histocompatibility complex, were completely removed. ICAM-1 was redistributed on the cell surface after the disruption of actin filaments with cytochalasin B, suggesting interaction with the actin cytoskeleton. In contrast, ICAM-1 was completely detergent soluble in rat pulmonary artery endothelial cells, human umbilical vein endothelial cells, and rat alveolar macrophages. The association of ICAM-1 with the alveolar epithelial cell cytoskeleton was not altered after stimulation with inflammatory cytokines. However, detergent resistant ICAM-1 was significantly increased after crosslinking of ICAM-1 on the cell surface, suggesting that this cytoskeletal association may be modulated by interactions of alveolar epithelial cells with inflammatory cells. The association of ICAM-1 with the cytoskeleton in alveolar epithelial cells may provide a fixed intermediary between mobile inflammatory cells and the alveolar surface. PMID:8944713

  4. Substrate stiffness regulates extracellular matrix deposition by alveolar epithelial cells

    PubMed Central

    Eisenberg, Jessica L; Safi, Asmahan; Wei, Xiaoding; Espinosa, Horacio D; Budinger, GR Scott; Takawira, Desire; Hopkinson, Susan B; Jones, Jonathan CR

    2012-01-01

    Aim The aim of the study was to address whether a stiff substrate, a model for pulmonary fibrosis, is responsible for inducing changes in the phenotype of alveolar epithelial cells (AEC) in the lung, including their deposition and organization of extracellular matrix (ECM) proteins. Methods Freshly isolated lung AEC from male Sprague Dawley rats were seeded onto polyacrylamide gel substrates of varying stiffness and analyzed for expression and organization of adhesion, cytoskeletal, differentiation, and ECM components by Western immunoblotting and confocal immunofluorescence microscopy. Results We observed that substrate stiffness influences cell morphology and the organization of focal adhesions and the actin cytoskeleton. Surprisingly, however, we found that substrate stiffness has no influence on the differentiation of type II into type I AEC, nor does increased substrate stiffness lead to an epithelial–mesenchymal transition. In contrast, our data indicate that substrate stiffness regulates the expression of the α3 laminin subunit by AEC and the organization of both fibronectin and laminin in their ECM. Conclusions An increase in substrate stiffness leads to enhanced laminin and fibronectin assembly into fibrils, which likely contributes to the disease phenotype in the fibrotic lung. PMID:23204878

  5. Thrombin-induced contraction in alveolar epithelial cells probed by traction microscopy.

    PubMed

    Gavara, Núria; Sunyer, Raimon; Roca-Cusachs, Pere; Farré, Ramon; Rotger, Mar; Navajas, Daniel

    2006-08-01

    Contractile tension of alveolar epithelial cells plays a major role in the force balance that regulates the structural integrity of the alveolar barrier. The aim of this work was to study thrombin-induced contractile forces of alveolar epithelial cells. A549 alveolar epithelial cells were challenged with thrombin, and time course of contractile forces was measured by traction microscopy. The cells exhibited basal contraction with total force magnitude 55.0 +/- 12.0 nN (mean +/- SE, n = 12). Traction forces were exerted predominantly at the cell periphery and pointed to the cell center. Thrombin (1 U/ml) induced a fast and sustained 2.5-fold increase in traction forces, which maintained peripheral and centripetal distribution. Actin fluorescent staining revealed F-actin polymerization and enhancement of peripheral actin rim. Disruption of actin cytoskeleton with cytochalasin D (5 microM, 30 min) and inhibition of myosin light chain kinase with ML-7 (10 microM, 30 min) and Rho kinase with Y-27632 (10 microM, 30 min) markedly depressed basal contractile tone and abolished thrombin-induced cell contraction. Therefore, the contractile response of alveolar epithelial cells to the inflammatory agonist thrombin was mediated by actin cytoskeleton remodeling and actomyosin activation through myosin light chain kinase and Rho kinase signaling pathways. Thrombin-induced contractile tension might further impair alveolar epithelial barrier integrity in the injured lung. PMID:16675616

  6. Vasoactive intestinal peptide protects alveolar epithelial cells against hyperoxia via promoting the activation of STAT3.

    PubMed

    Ao, Xiaoxiao; Fang, Fang; Xu, Feng

    2011-06-01

    Oxidative stress injury and death in alveolar epithelial cells plays an important role in the pathogenesis of prolonged hyperoxia-induced lung impairment. A reduced survival of type II alveolar epithelial cells (AECIIs) may lead to abnormal repair, resulting in acute and chronic pulmonary diseases. Hyperoxia lung injury is associated with the secretion of various bioactive substances and the activation of multiple transcription factors. Vasoactive intestinal peptide (VIP), as a pulmonary sensory neuropeptide, performs a vital function in regulating cell proliferation and cell death through signal transducers and activators of transcription 3 (STAT3). In the present study, we investigated the effects of VIP and STAT3 on AECIIs upon the exposure of hyperoxia. MLE-12 cells were random to air (21% oxygen), hyperoxia (95% oxygen) and VIP treatment with or without STAT3 siRNA transfection. The proliferation of AECIIs was detected by MTT cell proliferation assay. The apoptosis rate was measured by flow cytometry. Mitochondrial membrane potential was evaluated by fluorescent dye JC-1 to understand mitochondrial and cell damage. The activation of STAT3 was assessed by western blot detection of phosphorylated STAT3. Compared with hyperoxia exposure alone, additional VIP treatment promoted cell proliferation, maintained the mitochondrial membrane potential and reduced the apoptosis and necrosis of AECIIs. The protective effects aforesaid were weakened after STAT3 expression was down regulated by siRNA. Cells with STAT3 siRNA transfection had a higher mortality and a sharper decline in the mitochondrial membrane potential as well as a lower proliferation compared with wild-type cells after hyperoxia exposure with VIP administration. VIP interference, a protective management, could decrease hyperoxia-induced cell injury and death and improve the survival of AECIIs exposed to hyperoxia, which might be associated with the activation of STAT3. PMID:21334383

  7. Ozone Exposure of Macrophages Induces an Alveolar Epithelial Chemokine Response through IL-1α

    PubMed Central

    Manzer, Rizwan; Dinarello, Charles A.; McConville, Glen; Mason, Robert J.

    2008-01-01

    Ozone is known to produce an acute influx of neutrophils, and alveolar epithelial cells can secrete chemokines and modulate inflammatory processes. However, direct exposure of alveolar epithelial cells and macrophages to ozone (O3) produces little chemokine response. To determine if cell–cell interactions might be responsible, we investigated the effect of alveolar macrophage–conditioned media after ozone exposure (MO3CM) on alveolar epithelial cell chemokine production. Serum-free media were conditioned by exposing a rat alveolar macrophage cell line NR8383 to ozone for 1 hour. Ozone stimulated secretion of IL-1α, IL-1β, and IL-18 from NR8383 cells, but there was no secretion of chemokines or TNF-α. Freshly isolated type II cells were cultured, so as to express the biological markers of type I cells, and these cells are referred to as type I–like cells. Type I–like cells were exposed to diluted MO3CM for 24 hours, and this conditioned medium stimulated secretion of cytokine-induced neutrophil chemattractant-1 (CXCL1) and monocyte chemoattractant protein-1 (CCL2). Secretion of these chemokines was inhibited by the IL-1 receptor antagonist. Although both recombinant IL-1α and IL-1β stimulated alveolar epithelial cells to secrete chemokines, recombinant IL-1α was 100-fold more potent than IL-1β. Furthermore, neutralizing anti-rat IL-1α antibodies inhibited the secretion of chemokines by alveolar epithelial cells, whereas neutralizing anti-rat IL-1β antibodies had no effect. These observations indicate that secretion of IL-1α from macrophages stimulates alveolar epithelial cells to secrete chemokines that can elicit an inflammatory response. PMID:17901407

  8. Effect of alveolar epithelial cell plasticity on the regulation of GM-CSF expression.

    PubMed

    Mir-Kasimov, Mustafa; Sturrock, Anne; McManus, Michael; Paine, Robert

    2012-03-15

    Local pulmonary expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) is critically important for defense of the pulmonary alveolar space. It is required for surfactant homeostasis and pulmonary innate immune responses and is protective against lung injury and aberrant repair. Alveolar epithelial cells (AEC) are a major source of GM-CSF; however, the control of homeostatic expression of GM-CSF is incompletely characterized. Increasing evidence suggests considerable plasticity of expression of AEC phenotypic characteristics. We tested the hypothesis that this plasticity extends to regulation of expression of GM-CSF using 1) MLE-12 cells (a commonly used murine cell line expressing some features of normal type II AEC, 2) primary murine AEC incubated under standard conditions [resulting in rapid spreading and loss of surfactant protein C (SP-C) expression with induction of the putative type I cell marker (T1α)], or 3) primary murine AEC on a hyaluronic acid/collagen matrix in defined medium, resulting in preservation of SP-C expression. AEC in standard cultures constitutively express abundant GM-CSF, with further induction in response to IL-1β but little response to TNF-α. In contrast, primary cells cultured to preserve SP-C expression and MLE-12 cells both express little GM-CSF constitutively, with significant induction in response to TNF-α and limited response to IL-1β. We conclude that constitutive and cytokine-induced expression of GM-CSF by AEC varies in concert with other cellular phenotypic characteristics. These changes may have important implications both for the maintenance of normal pulmonary homeostasis and for the process of repair following lung injury. PMID:22227205

  9. The Role of Mitochondrial DNA in Mediating Alveolar Epithelial Cell Apoptosis and Pulmonary Fibrosis

    PubMed Central

    Kim, Seok-Jo; Cheresh, Paul; Jablonski, Renea P.; Williams, David B.; Kamp, David W.

    2015-01-01

    Convincing evidence has emerged demonstrating that impairment of mitochondrial function is critically important in regulating alveolar epithelial cell (AEC) programmed cell death (apoptosis) that may contribute to aging-related lung diseases, such as idiopathic pulmonary fibrosis (IPF) and asbestosis (pulmonary fibrosis following asbestos exposure). The mammalian mitochondrial DNA (mtDNA) encodes for 13 proteins, including several essential for oxidative phosphorylation. We review the evidence implicating that oxidative stress-induced mtDNA damage promotes AEC apoptosis and pulmonary fibrosis. We focus on the emerging role for AEC mtDNA damage repair by 8-oxoguanine DNA glycosylase (OGG1) and mitochondrial aconitase (ACO-2) in maintaining mtDNA integrity which is important in preventing AEC apoptosis and asbestos-induced pulmonary fibrosis in a murine model. We then review recent studies linking the sirtuin (SIRT) family members, especially SIRT3, to mitochondrial integrity and mtDNA damage repair and aging. We present a conceptual model of how SIRTs modulate reactive oxygen species (ROS)-driven mitochondrial metabolism that may be important for their tumor suppressor function. The emerging insights into the pathobiology underlying AEC mtDNA damage and apoptosis is suggesting novel therapeutic targets that may prove useful for the management of age-related diseases, including pulmonary fibrosis and lung cancer. PMID:26370974

  10. Endocytic response of type I alveolar epithelial cells to hypertonic stress

    PubMed Central

    Wang, Shaohua; Singh, Raman Deep; Godin, Lindsay; Pagano, Richard E.

    2011-01-01

    We present plasma membrane (PM) internalization responses of type I alveolar epithelial cells to a 50 mosmol/l increase in tonicity. Our research is motivated by interest in ATI repair, for which endocytic retrieval of PM appears to be critical. We validated pharmacological and molecular tools to dissect the endocytic machinery of these cells and used these tools to test the hypothesis that osmotic stress triggers a pathway-specific internalization of PM domains. Validation experiments confirmed the fluorescent analogs of lactosyl-ceramide, transferrin, and dextran as pathway-specific cargo of caveolar, clathrin, and fluid-phase uptake, respectively. Pulse-chase experiments indicate that hypertonic exposure causes a downregulation of clathrin and fluid-phase endocytosis while stimulating caveolar endocytosis. The tonicity-mediated increase in caveolar endocytosis was associated with the translocation of caveolin-1 from the PM and was absent in cells that had been transfected with dominant-negative dynamin constructs. In separate experiments we show that hypertonic exposure increases the probability of PM wound repair following micropuncture from 82 ± 4 to 94 ± 2% (P < 0.01) and that this effect depends on Src pathway activation-mediated caveolar endocytosis. The therapeutic and biological implications of our findings are discussed. PMID:21257731

  11. Potassium currents in rat type II alveolar epithelial cells.

    PubMed Central

    DeCoursey, T E; Jacobs, E R; Silver, M R

    1988-01-01

    1. Type II alveolar epithelial cells isolated from adult rats and grown in primary culture were studied using the whole-cell configuration of the gigohm-seal voltage clamp technique. 2. The average specific capacitance of type II cells was 2.5 microF/cm2, suggesting that type II cell membranes in vitro are irregular, with an actual area more than twice the apparent area. 3. Most type II cells have time- and voltage-dependent outward currents carried by potassium ions. Potassium currents activate with a sigmoid time course upon membrane depolarization, and inactivate during maintained depolarization. The average maximum whole-cell K+ conductance was 1.6 nS. 4. Two distinct types of K+-selective channels underlie outward currents in type II cells. Most cells have currents resembling delayed rectifier K+ currents in skeletal muscle, nerve and immune cells. A few cells had a different type of K+ conductance which is more sensitive to block by tetraethylammonium ions, has faster 'tail currents', and activates at more positive potentials. 5. In some experiments, individual type II cells were identified by staining with phosphine, a fluorescent dye which is concentrated in lamellar bodies. Both types of K+ channels were seen in type II cells identified with this dye. 6. Phosphine added to the bathing solution reversibly reduced K+ currents and shifted K+ channel activation to more positive potentials. Excitation of phosphine to fluoresce reduced irreversibly K+ currents in type II cells. The usefulness of phosphine as a means of identifying cells for study is discussed. PMID:2457683

  12. Characterizing mutagenesis in the hprt gene of rat alveolar epithelial cells

    SciTech Connect

    Driscoll, K.E.; Deyo, L.C.; Howard, B.W.

    1995-12-31

    A clonal selection assay was developed for mutation in the hypoxanthine-guanine phosphoribosyl transferase (hprt) gene of rat alveolar epithelial cells. Studies were conducted to establish methods for isolation and long-term culture of rat alveolar epithelial cells. When isolated by pronase digestion purified on a Nycodenz gradient and cultured in media containing 7.5% fetal bovine serum (FBS), pituitary extract, EGF, insulin, and IGF-1, rat alveolar epithelial cells could be maintained in culture for several weeks with cell doubling times of 2-4 days. The rat alveolar epithelial cell cultures were exposed in vitro to the mutagens ethylnitrosourea (ENU) and H{sub 2}O{sub 2}, and mutation in the hprt gene was selected for by culture in the presence of the toxic purine analog, 6-thioguanine (6TG). In vitro exposure to ENU or H{sub 2}O produced a dose-dependent increase in hprt mutation frequency in the alveolar epithelial cells. To determine if the assay system could be used to evaluate mutagenesis in alveolar type II cells after in vivo mutagen or carcinogen exposure, cells were isolated from rats treated previously with ENU or {alpha}-quartz. A significant increase in hprt mutation frequency was detected in alveolar epithelial cells obtained from rats exposed to ENU or {alpha}-quartz; the latter observation is the first demonstration that crystalline silica exposure is mutagenic in vivo. In summary, these studies show that rat alveolar epithelial cells isolated by pronase digestion and Nycodenz separation techniques and cultured in a defined media can be used in a clonal selection assay for mutation in the hprt gene. This assay demonstrates that ENU and H{sub 2}O{sub 2} in vitro and ENU and {alpha}-quartz in vivo are mutagenic for rat alveolar epithelial cells. This model should be useful for investigating the genotoxic effects of chemical and physical agents on an important lung cell target for neoplastic transformation. 41 refs., 4 figs., 3 tabs.

  13. Enolase 1 (ENO1) and protein disulfide-isomerase associated 3 (PDIA3) regulate Wnt/β-catenin-driven trans-differentiation of murine alveolar epithelial cells

    PubMed Central

    Mutze, Kathrin; Vierkotten, Sarah; Milosevic, Jadranka; Eickelberg, Oliver; Königshoff, Melanie

    2015-01-01

    ABSTRACT The alveolar epithelium represents a major site of tissue destruction during lung injury. It consists of alveolar epithelial type I (ATI) and type II (ATII) cells. ATII cells are capable of self-renewal and exert progenitor function for ATI cells upon alveolar epithelial injury. Cell differentiation pathways enabling this plasticity and allowing for proper repair, however, are poorly understood. Here, we applied proteomics, expression analysis and functional studies in primary murine ATII cells to identify proteins and molecular mechanisms involved in alveolar epithelial plasticity. Mass spectrometry of cultured ATII cells revealed a reduction of carbonyl reductase 2 (CBR2) and an increase in enolase 1 (ENO1) and protein disulfide-isomerase associated 3 (PDIA3) protein expression during ATII-to-ATI cell trans-differentiation. This was accompanied by increased Wnt/β-catenin signaling, as analyzed by qRT-PCR and immunoblotting. Notably, ENO1 and PDIA3, along with T1α (podoplanin; an ATI cell marker), exhibited decreased protein expression upon pharmacological and molecular Wnt/β-catenin inhibition in cultured ATII cells, whereas CBR2 levels were stabilized. Moreover, we analyzed primary ATII cells from mice with bleomycin-induced lung injury, a model exhibiting activated Wnt/β-catenin signaling in vivo. We observed reduced CBR2 significantly correlating with surfactant protein C (SFTPC), whereas ENO1 and PDIA3 along with T1α were increased in injured ATII cells. Finally, siRNA-mediated knockdown of ENO1, as well as PDIA3, in primary ATII cells led to reduced T1α expression, indicating diminished cell trans-differentiation. Our data thus identified proteins involved in ATII-to-ATI cell trans-differentiation and suggest a Wnt/β-catenin-driven functional role of ENO1 and PDIA3 in alveolar epithelial cell plasticity in lung injury and repair. PMID:26035385

  14. Oxidized glutathione (GSSG) inhibits epithelial sodium channel activity in primary alveolar epithelial cells

    PubMed Central

    Downs, Charles A.; Kreiner, Lisa; Zhao, Xing-Ming; Trac, Phi; Johnson, Nicholle M.; Hansen, Jason M.; Brown, Lou Ann

    2015-01-01

    Amiloride-sensitive epithelial Na+ channels (ENaC) regulate fluid balance in the alveoli and are regulated by oxidative stress. Since glutathione (GSH) is the predominant antioxidant in the lungs, we proposed that changes in glutathione redox potential (Eh) would alter cell signaling and have an effect on ENaC open probability (Po). In the present study, we used single channel patch-clamp recordings to examine the effect of oxidative stress, via direct application of glutathione disulfide (GSSG), on ENaC activity. We found a linear decrease in ENaC activity as the GSH/GSSG Eh became less negative (n = 21; P < 0.05). Treatment of 400 μM GSSG to the cell bath significantly decreased ENaC Po from 0.39 ± 0.06 to 0.13 ± 0.05 (n = 8; P < 0.05). Likewise, back-filling recording electrodes with 400 μM GSSG reduced ENaC Po from 0.32 ± 0.08 to 0.17 ± 0.05 (n = 10; P < 0.05), thus implicating GSSG as an important regulatory factor. Biochemical assays indicated that oxidizing potentials promote S-glutathionylation of ENaC and irreversible oxidation of cysteine residues with N-ethylmaleimide blocked the effects of GSSG on ENaC Po. Additionally, real-time imaging studies showed that GSSG impairs alveolar fluid clearance in vivo as opposed to GSH, which did not impair clearance. Taken together, these data show that glutathione Eh is an important determinant of alveolar fluid clearance in vivo. PMID:25713321

  15. Dexmedetomidine Attenuates Bilirubin-Induced Lung Alveolar Epithelial Cell Death In Vitro and In Vivo*

    PubMed Central

    Cui, Jian; Zhao, Hailin; Yi, Bin; Zeng, Jing; Lu, Kaizhi

    2015-01-01

    Objective: To investigate bilirubin-induced lung alveolar epithelial cell injury together with the protection afforded by dexmedetomidine. Design: Prospective, randomized, controlled study. Setting: Research laboratory. Subjects: Sprague Dawley rats. Interventions: Alveolar epithelial A549 cell lines were cultured and received bilirubin (from 0 to 160 μM) to explore the protective pathway of dexmedetomidine on bilirubin-induced alveolar epithelial cell injury assessed by immunochemistry and flow cytometry. Sprague-Dawley rats were subjected to common bile duct ligation surgery to explore the protective effect of dexmedetomidine on hyperbilirubinemia-induced alveolar epithelial cell injury and respiratory failure in comparison with the Sham (subjected to the surgery procedure but without bile duct ligation) or dexmedetomidine control (only received intraperitoneal injection of dexmedetomidine). Measurements and Main Results: In vitro, dexmedetomidine reversed the collapse of mitochondrial membrane potential (Δψm), upregulation of cytochrome C, B cell leukemia 2 associated X protein, and cleaved-caspase 3 and 9 in A549 epithelial cells with bilirubin challenge. Furthermore, dexmedetomidine reversed the arrest of cell cycle and the downregulation of the transforming growth factorβ, phosphorylated mammalian target of rapamycin, and p42/44 mitogen-activated protein kinase induced by bilirubin. In vivo, pulmonary edema and inflammation were found after common bile duct ligation. Bilirubin and Paco2 were significantly increased, and oxygen (Pao2) was significantly decreased in the blood of common bile duct ligation rats from the postsurgery day 7 to day 21 when compared with those in the sham controls, respectively (p < 0.01). Daily intraperitoneal injection of dexmedetomidine significantly alleviated the lung edema and injury and prevented respiratory failure. Conclusion: Our data both in vitro and in vivo demonstrated that dexmedetomidine protected alveolar

  16. Evidence that exogenous substances can be phagocytized by alveolar epithelial cells and transported into blood capillaries.

    PubMed

    Kato, Tomoko; Yashiro, Takashi; Murata, Yoshio; Herbert, Damon C; Oshikawa, Katsuhisa; Bando, Masashi; Ohno, Shoji; Sugiyama, Yukihiko

    2003-01-01

    Since the ability of alveolar epithelial cells to ingest inhaled fine particles has not been characterized in detail, the present study seeks to evaluate this physiological activity. We used a 0.2% suspension of intact or lecithin-coated polystyrene latex beads (240 nm in diameter). A 5-ml suspension of intact or lecithin-coated latex beads was intratracheally administered to rats using a compressor nebulizer. Thereafter, the lungs were perfused intratracheally with glutaraldehyde solution and cut into small pieces. The samples were postfixed with osmium tetroxide, embedded in epoxy resin and examined under an electron microscope. Both lecithin-coated and uncoated beads were incorporated into alveolar macrophages. Some of the ingested beads in the alveolar macrophages were sequestered within lysosomes. Types I and II alveolar epithelial cells selectively incorporated only lecithin-coated beads, which were also observed within the cytoplasm of monocytes in the capillary lumen. These findings suggest that alveolar epithelial cells can incorporate exogenous particles, which are then transferred from the alveoli to intravascular spaces by transcytosis. PMID:12483283

  17. Replication of parainfluenza (Sendai) virus in isolated rat pulmonary type II alveolar epithelial cells.

    PubMed Central

    Castleman, W. L.; Northrop, P. J.; McAllister, P. K.

    1989-01-01

    The major objectives of this study were to determine whether alveolar type II epithelial cells isolated from rat lung and maintained in tissue culture would support productive replication of parainfluenza type 1 (Sendai) virus and to determine whether isolated type II cells from neonatal (5-day-old) rats that are more susceptible to viral-induced alveolar dysplasia supported viral replication to a greater extent than those from weanling (25-day-old) rats. Isolated and cultured type II cells from neonatal and weanling rats that were inoculated with Sendai virus supported productive replication as indicated by ultrastructural identification of budding virions and viral nucleocapsids in type II cells and by demonstration of rising titers of infectious virus from inoculated type II cell cultures. Alveolar macrophages from neonatal and weanling rats also supported viral replication, although infectious viral titers in macrophage cultures were lower than those from type II cell cultures. Only minor differences were detected between viral titers from neonatal and weanling type II epithelial cell cultures. Higher densities of viral nucleocapsids were observed in neonatal type II cells than in those from weanling rats. The results indicate that isolated type II alveolar epithelial cells support productive replication of parainfluenza virus and that type II cells are probably more efficient in supporting productive viral replication than are alveolar macrophages. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:2541612

  18. Influenza virus damages the alveolar barrier by disrupting epithelial cell tight junctions.

    PubMed

    Short, Kirsty R; Kasper, Jennifer; van der Aa, Stijn; Andeweg, Arno C; Zaaraoui-Boutahar, Fatiha; Goeijenbier, Marco; Richard, Mathilde; Herold, Susanne; Becker, Christin; Scott, Dana P; Limpens, Ronald W A L; Koster, Abraham J; Bárcena, Montserrat; Fouchier, Ron A M; Kirkpatrick, Charles James; Kuiken, Thijs

    2016-03-01

    A major cause of respiratory failure during influenza A virus (IAV) infection is damage to the epithelial-endothelial barrier of the pulmonary alveolus. Damage to this barrier results in flooding of the alveolar lumen with proteinaceous oedema fluid, erythrocytes and inflammatory cells. To date, the exact roles of pulmonary epithelial and endothelial cells in this process remain unclear.Here, we used an in vitro co-culture model to understand how IAV damages the pulmonary epithelial-endothelial barrier. Human epithelial cells were seeded on the upper half of a transwell membrane while human endothelial cells were seeded on the lower half. These cells were then grown in co-culture and IAV was added to the upper chamber.We showed that the addition of IAV (H1N1 and H5N1 subtypes) resulted in significant barrier damage. Interestingly, we found that, while endothelial cells mounted a pro-inflammatory/pro-coagulant response to a viral infection in the adjacent epithelial cells, damage to the alveolar epithelial-endothelial barrier occurred independently of endothelial cells. Rather, barrier damage was associated with disruption of tight junctions amongst epithelial cells, and specifically with loss of tight junction protein claudin-4.Taken together, these data suggest that maintaining epithelial cell integrity is key in reducing pulmonary oedema during IAV infection. PMID:26743480

  19. NLRP3 protects alveolar barrier integrity by an inflammasome-independent increase of epithelial cell adherence.

    PubMed

    Kostadinova, Elena; Chaput, Catherine; Gutbier, Birgitt; Lippmann, Juliane; Sander, Leif E; Mitchell, Timothy J; Suttorp, Norbert; Witzenrath, Martin; Opitz, Bastian

    2016-01-01

    Bacterial pneumonia is a major cause of acute lung injury and acute respiratory distress syndrome, characterized by alveolar barrier disruption. NLRP3 is best known for its ability to form inflammasomes and to regulate IL-1β and IL-18 production in myeloid cells. Here we show that NLRP3 protects the integrity of the alveolar barrier in a mouse model of Streptococcus pneumoniae-induced pneumonia, and ex vivo upon treatment of isolated perfused and ventilated lungs with the purified bacterial toxin, pneumolysin. We reveal that the preserving effect of NLRP3 on the lung barrier is independent of inflammasomes, IL-1β and IL-18. NLRP3 improves the integrity of alveolar epithelial cell monolayers by enhancing cellular adherence. Collectively, our study uncovers a novel function of NLRP3 by demonstrating that it protects epithelial barrier function independently of inflammasomes. PMID:27476670

  20. NLRP3 protects alveolar barrier integrity by an inflammasome-independent increase of epithelial cell adherence

    PubMed Central

    Kostadinova, Elena; Chaput, Catherine; Gutbier, Birgitt; Lippmann, Juliane; Sander, Leif E.; Mitchell, Timothy J.; Suttorp, Norbert; Witzenrath, Martin; Opitz, Bastian

    2016-01-01

    Bacterial pneumonia is a major cause of acute lung injury and acute respiratory distress syndrome, characterized by alveolar barrier disruption. NLRP3 is best known for its ability to form inflammasomes and to regulate IL-1β and IL-18 production in myeloid cells. Here we show that NLRP3 protects the integrity of the alveolar barrier in a mouse model of Streptococcus pneumoniae-induced pneumonia, and ex vivo upon treatment of isolated perfused and ventilated lungs with the purified bacterial toxin, pneumolysin. We reveal that the preserving effect of NLRP3 on the lung barrier is independent of inflammasomes, IL-1β and IL-18. NLRP3 improves the integrity of alveolar epithelial cell monolayers by enhancing cellular adherence. Collectively, our study uncovers a novel function of NLRP3 by demonstrating that it protects epithelial barrier function independently of inflammasomes. PMID:27476670

  1. Human alveolar epithelial cells expressing tight junctions to model the air-blood barrier.

    PubMed

    Kuehn, Anna; Kletting, Stephanie; de Souza Carvalho-Wodarz, Cristiane; Repnik, Urska; Griffiths, Gareth; Fischer, Ulrike; Meese, Eckart; Huwer, Hanno; Wirth, Dagmar; May, Tobias; Schneider-Daum, Nicole; Lehr, Claus-Michael

    2016-01-01

    This paper describes a new human alveolar epithelial cell line (hAELVi - human Alveolar Epithelial Lentivirus immortalized) with type I-like characteristics and functional tight junctions, suitable to model the air-blood barrier of the peripheral lung. Primary human alveolar epithelial cells were immortalized by a novel regimen, grown as monolayers on permeable filter supports and characterized morphologically, biochemically and biophysically. hAELVi cells maintain the capacity to form tight intercellular junctions, with high trans-epithelial electrical resistance (> 1000 Ω*cm²). The cells could be kept in culture over several days, up to passage 75, under liquid-liquid as well as air-liquid conditions. Ultrastructural analysis and real time PCR revealed type I-like cell properties, such as the presence of caveolae, expression of caveolin-1, and absence of surfactant protein C. Accounting for the barrier properties, inter-digitations sealed with tight junctions and desmosomes were also observed. Low permeability of the hydrophilic marker sodium fluorescein confirmed the suitability of hAELVi cells for in vitro transport studies across the alveolar epithelium. These results suggest that hAELVi cells reflect the essential features of the air-blood barrier, as needed for an alternative to animal testing to study absorption and toxicity of inhaled drugs, chemicals and nanomaterials. PMID:26985677

  2. Alveolar epithelial cells express mesenchymal proteins in patients with idiopathic pulmonary fibrosis.

    PubMed

    Marmai, Cecilia; Sutherland, Rachel E; Kim, Kevin K; Dolganov, Gregory M; Fang, Xiaohui; Kim, Sophia S; Jiang, Shuwei; Golden, Jeffery A; Hoopes, Charles W; Matthay, Michael A; Chapman, Harold A; Wolters, Paul J

    2011-07-01

    Prior work has shown that transforming growth factor-β (TGF-β) can mediate transition of alveolar type II cells into mesenchymal cells in mice. Evidence this occurs in humans is limited to immunohistochemical studies colocalizing epithelial and mesenchymal proteins in sections of fibrotic lungs. To acquire further evidence that epithelial-to-mesenchymal transition occurs in the lungs of patients with idiopathic pulmonary fibrosis (IPF), we studied alveolar type II cells isolated from fibrotic and normal human lung. Unlike normal type II cells, type II cells isolated from the lungs of patients with IPF express higher levels of mRNA for the mesenchymal proteins type I collagen, α-smooth muscle actin (α-SMA), and calponin. When cultured on Matrigel/collagen, human alveolar type II cells maintain a cellular morphology consistent with epithelial cells and expression of surfactant protein C (SPC) and E-cadherin. In contrast, when cultured on fibronectin, the human type II cells flatten, spread, lose expression of pro- SPC, and increase expression of vimentin, N-cadherin, and α-SMA; markers of mesenchymal cells. Addition of a TGF-β receptor kinase inhibitor (SB431542) to cells cultured on fibronectin inhibited vimentin expression and maintained pro-SPC expression, indicating persistence of an epithelial phenotype. These data suggest that alveolar type II cells can acquire features of mesenchymal cells in IPF lungs and that TGF-β can mediate this process. PMID:21498628

  3. Alveolar epithelial cells express mesenchymal proteins in patients with idiopathic pulmonary fibrosis

    PubMed Central

    Marmai, Cecilia; Sutherland, Rachel E.; Kim, Kevin K.; Dolganov, Gregory M.; Fang, Xiaohui; Kim, Sophia S.; Jiang, Shuwei; Golden, Jeffery A.; Hoopes, Charles W.; Matthay, Michael A.; Chapman, Harold A.

    2011-01-01

    Prior work has shown that transforming growth factor-β (TGF-β) can mediate transition of alveolar type II cells into mesenchymal cells in mice. Evidence this occurs in humans is limited to immunohistochemical studies colocalizing epithelial and mesenchymal proteins in sections of fibrotic lungs. To acquire further evidence that epithelial-to-mesenchymal transition occurs in the lungs of patients with idiopathic pulmonary fibrosis (IPF), we studied alveolar type II cells isolated from fibrotic and normal human lung. Unlike normal type II cells, type II cells isolated from the lungs of patients with IPF express higher levels of mRNA for the mesenchymal proteins type I collagen, α-smooth muscle actin (α-SMA), and calponin. When cultured on Matrigel/collagen, human alveolar type II cells maintain a cellular morphology consistent with epithelial cells and expression of surfactant protein C (SPC) and E-cadherin. In contrast, when cultured on fibronectin, the human type II cells flatten, spread, lose expression of pro- SPC, and increase expression of vimentin, N-cadherin, and α-SMA; markers of mesenchymal cells. Addition of a TGF-β receptor kinase inhibitor (SB431542) to cells cultured on fibronectin inhibited vimentin expression and maintained pro-SPC expression, indicating persistence of an epithelial phenotype. These data suggest that alveolar type II cells can acquire features of mesenchymal cells in IPF lungs and that TGF-β can mediate this process. PMID:21498628

  4. Sirtuin 1 Activator SRT1720 Protects Against Lung Injury via Reduction of Type II Alveolar Epithelial Cells Apoptosis in Emphysema.

    PubMed

    Gu, Chao; Li, Yaqing; Xu, Wu-Lin; Yan, Jian-Ping; Xia, Ying-jie; Ma, Ying-Yu; Chen, Chun; Wang, Hui-Ju; Tao, Hou-quan

    2015-08-01

    In chronic obstructive pulmonary disease (COPD), two major pathological changes that occur are the loss of alveolar structure and airspace enlargement. Type II alveolar epithelial cells (AECII) play a vital role in maintaining alveolar homeostasis and lung tissue repair. Sirtuin 1 (SIRT1), a NAD(+)-dependent histone deacetylase, regulates many pathophysiological processes including inflammation, apoptosis, cellular senescence and stress resistance. The main aim of this study was to investigate whether SRT1720, a pharmacological SIRT1 activator, could protect against AECII apoptosis in rats with emphysema caused by cigarette smoke exposure and intratracheal lipopolysaccharide instillation in vivo. During the induction of emphysema in rats, administration of SRT1720 improved lung function including airway resistance and pulmonary dynamic compliance. SRT1720 treatment up-regulated the levels of surfactant protein (SP)A, SPC, SIRT1 and forkhead box O 3, increased SIRT1 activity, down-regulated the level of p53 and inhibited AECII apoptosis. Lung injury caused by emphysema was alleviated after SRT1720 treatment. SRT1720 could protect against AECII apoptosis in rats with emphysema and thus could be used in COPD treatment. PMID:25415045

  5. Laser-activated solder weld repair of the inferior alveolar nerve in rats

    NASA Astrophysics Data System (ADS)

    Curtis, Nigel J.; Lauto, Antonio; Trickett, Rodney I.; Owen, Earl R.; Walker, D. M.

    1997-05-01

    A new laser activated solder weld technique is described for the microsurgical repair of the inferior alveolar nerve in rats. The laser weld technique used an albumin based solder, containing indocyanine cardiogreen, plus an infrared diode laser. Seven animals had inferior alveolar nerve repairs performed using the laser weld technique and these were compared against corresponding unoperated controls plus three cases of nerve section without repair. Histochemical analysis was performed utilizing neuron counts and horseradish peroxidase tracer (HRP) uptake in the trigeminal ganglion following sacrifice and staining of frozen sections with cresyl violet and diaminobenzidene. The results of this analysis showed comparable mean neuron counts and mean HRP uptake by neurons for the unoperated control and laser weld groups with considerable reduction of mean values in cases of nerve section with no repair. Sections of the repaired inferior alveolar nerves, stained with Masson's trichrome, showed no adverse reactions by axons or epineurium to the coagulative repair with the solder and demonstrated regeneration of myelinated axons at the time of sacrifice. In summary a new technique of laser weld repair of the inferior alveolar nerve is described which, on initial analysis, appears to be a reliable alternative to traditional techniques.

  6. Intrinsic epithelial cells repair the kidney after injury.

    PubMed

    Humphreys, Benjamin D; Valerius, M Todd; Kobayashi, Akio; Mugford, Joshua W; Soeung, Savuth; Duffield, Jeremy S; McMahon, Andrew P; Bonventre, Joseph V

    2008-03-01

    Understanding the mechanisms of nephron repair is critical for the design of new therapeutic approaches to treat kidney disease. The kidney can repair after even a severe insult, but whether adult stem or progenitor cells contribute to epithelial renewal after injury and the cellular origin of regenerating cells remain controversial. Using genetic fate-mapping techniques, we generated transgenic mice in which 94%-95% of tubular epithelial cells, but no interstitial cells, were labeled with either beta-galactosidase (lacZ) or red fluorescent protein (RFP). Two days after ischemia-reperfusion injury (IRI), 50.5% of outer medullary epithelial cells coexpress Ki67 and RFP, indicating that differentiated epithelial cells that survived injury undergo proliferative expansion. After repair was complete, 66.9% of epithelial cells had incorporated BrdU, compared to only 3.5% of cells in the uninjured kidney. Despite this extensive cell proliferation, no dilution of either cell-fate marker was observed after repair. These results indicate that regeneration by surviving tubular epithelial cells is the predominant mechanism of repair after ischemic tubular injury in the adult mammalian kidney. PMID:18371453

  7. Cigarette Smoke Enhances the Expression of Profibrotic Molecules in Alveolar Epithelial Cells

    PubMed Central

    Checa, Marco; Hagood, James S.; Velazquez-Cruz, Rafael; Ruiz, Victor; García-De-Alba, Carolina; Rangel-Escareño, Claudia; Urrea, Francisco; Becerril, Carina; Montaño, Martha; García-Trejo, Semiramis; Cisneros Lira, José; Aquino-Gálvez, Arnoldo; Pardo, Annie; Selman, Moisés

    2016-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal disease of unknown etiology. A growing body of evidence indicates that it may result from an aberrant activation of alveolar epithelium, which induces the expansion of the fibroblast population, their differentiation to myofibroblasts and the excessive accumulation of extracellular matrix. The mechanisms that activate the alveolar epithelium are unknown, but several studies indicate that smoking is the main environmental risk factor for the development of IPF. In this study we explored the effect of cigarette smoke on the gene expression profile and signaling pathways in alveolar epithelial cells. Lung epithelial cell line from human (A549), was exposed to cigarette smoke extract (CSE) for 1, 3, and 5 weeks at 1, 5 and 10% and gene expression was evaluated by complete transcriptome microarrays. Signaling networks were analyzed with the Ingenuity Pathway Analysis software. At 5 weeks of exposure, alveolar epithelial cells acquired a fibroblast-like phenotype. At this time, gene expression profile revealed a significant increase of more than 1000 genes and deregulation of canonical signaling pathways such as TGF-β and Wnt. Several profibrotic genes involved in EMT were over-expressed, and incomplete EMT was observed in these cells, and corroborated in mouse (MLE-12) and rat (RLE-6TN) epithelial cells. The secretion of activated TGF-β1 increased in cells exposed to cigarette smoke, which decreased when the integrin alpha v gene was silenced. These findings suggest that the exposure of alveolar epithelial cells to CSE induces the expression and release of a variety of profibrotic genes, and the activation of TGF-β1, which may explain at least partially, the increased risk of developing IPF in smokers. PMID:26934369

  8. Cigarette Smoke Enhances the Expression of Profibrotic Molecules in Alveolar Epithelial Cells.

    PubMed

    Checa, Marco; Hagood, James S; Velazquez-Cruz, Rafael; Ruiz, Victor; García-De-Alba, Carolina; Rangel-Escareño, Claudia; Urrea, Francisco; Becerril, Carina; Montaño, Martha; García-Trejo, Semiramis; Cisneros Lira, José; Aquino-Gálvez, Arnoldo; Pardo, Annie; Selman, Moisés

    2016-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal disease of unknown etiology. A growing body of evidence indicates that it may result from an aberrant activation of alveolar epithelium, which induces the expansion of the fibroblast population, their differentiation to myofibroblasts and the excessive accumulation of extracellular matrix. The mechanisms that activate the alveolar epithelium are unknown, but several studies indicate that smoking is the main environmental risk factor for the development of IPF. In this study we explored the effect of cigarette smoke on the gene expression profile and signaling pathways in alveolar epithelial cells. Lung epithelial cell line from human (A549), was exposed to cigarette smoke extract (CSE) for 1, 3, and 5 weeks at 1, 5 and 10% and gene expression was evaluated by complete transcriptome microarrays. Signaling networks were analyzed with the Ingenuity Pathway Analysis software. At 5 weeks of exposure, alveolar epithelial cells acquired a fibroblast-like phenotype. At this time, gene expression profile revealed a significant increase of more than 1000 genes and deregulation of canonical signaling pathways such as TGF-β and Wnt. Several profibrotic genes involved in EMT were over-expressed, and incomplete EMT was observed in these cells, and corroborated in mouse (MLE-12) and rat (RLE-6TN) epithelial cells. The secretion of activated TGF-β1 increased in cells exposed to cigarette smoke, which decreased when the integrin alpha v gene was silenced. These findings suggest that the exposure of alveolar epithelial cells to CSE induces the expression and release of a variety of profibrotic genes, and the activation of TGF-β1, which may explain at least partially, the increased risk of developing IPF in smokers. PMID:26934369

  9. Proinflammatory response of alveolar epithelial cells is enhanced by alveolar macrophage-produced TNF-alpha during pulmonary ischemia-reperfusion injury.

    PubMed

    Sharma, Ashish K; Fernandez, Lucas G; Awad, Alaa S; Kron, Irving L; Laubach, Victor E

    2007-07-01

    Pulmonary ischemia-reperfusion (IR) injury entails acute activation of alveolar macrophages followed by neutrophil sequestration. Although proinflammatory cytokines and chemokines such as TNF-alpha and monocyte chemoattractant protein-1 (MCP-1) from macrophages are known to modulate acute IR injury, the contribution of alveolar epithelial cells to IR injury and their intercellular interactions with other cell types such as alveolar macrophages and neutrophils remain unclear. In this study, we tested the hypothesis that following IR, alveolar macrophage-produced TNF-alpha further induces alveolar epithelial cells to produce key chemokines that could then contribute to subsequent lung injury through the recruitment of neutrophils. Cultured RAW264.7 macrophages and MLE-12 alveolar epithelial cells were subjected to acute hypoxia-reoxygenation (H/R) as an in vitro model of pulmonary IR. H/R (3 h/1 h) significantly induced KC, MCP-1, macrophage inflammatory protein-2 (MIP-2), RANTES, and IL-6 (but not TNF-alpha) by MLE-12 cells, whereas H/R induced TNF-alpha, MCP-1, RANTES, MIP-1alpha, and MIP-2 (but not KC) by RAW264.7 cells. These results were confirmed using primary murine alveolar macrophages and primary alveolar type II cells. Importantly, using macrophage and epithelial coculture methods, the specific production of TNF-alpha by H/R-exposed RAW264.7 cells significantly induced proinflammatory cytokine/chemokine expression (KC, MCP-1, MIP-2, RANTES, and IL-6) by MLE-12 cells. Collectively, these results demonstrate that alveolar type II cells, in conjunction with alveolar macrophage-produced TNF-alpha, contribute to the initiation of acute pulmonary IR injury via a proinflammatory cascade. The release of key chemokines, such as KC and MIP-2, by activated type II cells may thus significantly contribute to neutrophil sequestration during IR injury. PMID:17416740

  10. Plexins function in epithelial repair in both Drosophila and zebrafish

    PubMed Central

    Yoo, Sa Kan; Pascoe, Heath G.; Pereira, Telmo; Kondo, Shu; Jacinto, Antonio; Zhang, Xuewu; Hariharan, Iswar K.

    2016-01-01

    In most multicellular organisms, homeostasis is contingent upon maintaining epithelial integrity. When unanticipated insults breach epithelial barriers, dormant programmes of tissue repair are immediately activated. However, many of the mechanisms that repair damaged epithelia remain poorly characterized. Here we describe a role for Plexin A (PlexA), a protein with particularly well-characterized roles in axonal pathfinding, in the healing of damaged epithelia in Drosophila. Semaphorins, which are PlexA ligands, also regulate tissue repair. We show that Drosophila PlexA has GAP activity for the Rap1 GTPase, which is known to regulate the stability of adherens junctions. Our observations suggest that the inhibition of Rap1 activity by PlexA in damaged Drosophila epithelia allows epithelial remodelling, thus facilitating wound repair. We also demonstrate a role for Plexin A1, a zebrafish orthologue of Drosophila PlexA, in epithelial repair in zebrafish tail fins. Thus, plexins function in epithelial wound healing in diverse taxa. PMID:27452696

  11. Methemoglobin-induced signaling and chemokine responses in human alveolar epithelial cells

    PubMed Central

    Mumby, Sharon; Ramakrishnan, Latha; Evans, Timothy W.; Griffiths, Mark J. D.

    2013-01-01

    Diffuse alveolar hemorrhage is characterized by the presence of red blood cells and free hemoglobin in the alveoli and complicates a number of serious medical and surgical lung conditions including the pulmonary vasculitides and acute respiratory distress syndrome. In this study we investigated the hypothesis that exposure of human alveolar epithelial cells to hemoglobin and its breakdown products regulates chemokine release via iron- and oxidant-mediated activation of the transcription factor NF-κB. Methemoglobin alone stimulated the release of IL-8 and MCP-1 from A549 cells via activation of the NF-κB pathway; additionally, IL-8 required ERK activation and MCP-1 required JNK activation. Neither antioxidants nor iron chelators and knockdown of ferritin heavy and light chains affected these responses, indicating that iron and reactive oxygen species are not involved in the response of alveolar epithelial cells to methemoglobin. Incubation of primary cultures of human alveolar type 2 cells with methemoglobin resulted in a similar pattern of chemokine release and signaling pathway activation. In summary, we have shown for the first time that methemoglobin induced chemokine release from human lung epithelial cells independent of iron- and redox-mediated signaling involving the activation of the NF-κB and MAPK pathways. Decompartmentalization of hemoglobin may be a significant proinflammatory stimulus in a variety of lung diseases. PMID:24142518

  12. Regulation of epithelial sodium channel expression by oestradiol and progestogen in alveolar epithelial cells.

    PubMed

    Luo, Ling; Deng, Jia; Wang, Dao-xin; He, Jing; Deng, Wang

    2015-09-15

    Oestrogen (E) and progestogen (P) exert regulatory effects on the epithelial Na(+) channel (ENaC) in the kidneys and the colon. However, the effects of E and P on the ENaC and on alveolar fluid clearance (AFC) remain unclear, and the mechanisms of action of these hormones are unknown. In this study, we showed that E and/or P administration increased AFC by more than 25% and increased the expression of the α and γ subunits of ENaC by approximately 35% in rats subjected to oleic acid-induced acute lung injury (ALI). A similar effect was observed in the dexamethasone-treated group. Furthermore, E and/or P treatment inhibited 11β-hydroxysteroid dehydrogenase (HSD) type 2 (11β-HSD2) activity, increased corticosterone expression and decreased the serum adrenocorticotrophic hormone (ACTH) levels. These effects were similar to those observed following treatment with carbenoxolone (CBX), a nonspecific HSD inhibitor. Further investigation showed that CBX further significantly increased AFC and α-ENaC expression after treatment with a low dose of E and/or P. In vitro, E or P alone inhibited 11β-HSD2 activity in a dose-dependent manner and increased α-ENaC expression by at least 50%, and E combined with P increased α-ENaC expression by more than 80%. Thus, E and P may augment the expression of α-ENaC, enhance AFC, attenuate pulmonary oedema by inhibiting 11β-HSD2 activity, and increase the active glucocorticoid levels in vivo and in vitro. PMID:26051998

  13. Ultrastructural evidence of alveolar epithelial injury in idiopathic bronchiolitis obliterans-organizing pneumonia.

    PubMed Central

    Myers, J. L.; Katzenstein, A. L.

    1988-01-01

    The ultrastructural features of idiopathic bronchiolitis obliterans-organizing pneumonia (BOOP) were studied in 9 patients. As expected, the characteristic air space fibrosis was composed of spindled fibroblasts and myofibroblasts arranged concentrically within an electron-lucent stroma. In 6 patients there was evidence of incorporation of air space fibrosis into the interstitium. A surprising finding in all patients was the presence of extensive epithelial damage involving peribronchiolar alveolar septa. Necrosis and sloughing of alveolar lining cells resulted in denuding of epithelial basal laminae. Complex infoldings and deep invaginations of the denuded basal laminae into alveolar septa were common. These ultrastructural changes involving the interstitium are similar to those occurring in the interstitial pneumonias, and suggest that BOOP also results from acute epithelial injury. The different clinical manifestations and prognosis of these entities may relate to the peribronchiolar localization of the epithelial damage in BOOP compared with more diffuse involvement of distal lung in the interstitial pneumonias. Images Figure 2 Figure 3 Figure 1 Figure 4 Figure 5 Figure 6 Figure 7 PMID:3394793

  14. The vitronectin RGD motif regulates TGF-β-induced alveolar epithelial cell apoptosis.

    PubMed

    Wheaton, Amanda K; Velikoff, Miranda; Agarwal, Manisha; Loo, Tiffany T; Horowitz, Jeffrey C; Sisson, Thomas H; Kim, Kevin K

    2016-06-01

    Transforming growth factor-β (TGF-β) is a critical driver of acute lung injury and fibrosis. Injury leads to activation of TGF-β, which regulates changes in the cellular and matrix makeup of the lung during the repair and fibrosis phase. TGF-β can also initiate alveolar epithelial cell (AEC) apoptosis. Injury leads to destruction of the laminin-rich basement membrane, which is replaced by a provisional matrix composed of arginine-glycine-aspartate (RGD) motif-containing plasma matrix proteins, including vitronectin and fibronectin. To determine the role of specific matrix proteins on TGF-β-induced apoptosis, we studied primary AECs cultured on different matrix conditions and utilized mice with deletion of vitronectin (Vtn(-/-)) or mice in which the vitronectin RGD motif is mutated to nonintegrin-binding arginine-glycine-glutamate (RGE) (Vtn(RGE/RGE)). We found that AECs cultured on fibronectin and vitronectin or in wild-type mouse serum are resistant to TGF-β-induced apoptosis. In contrast, AECs cultured on laminin or in serum from Vtn(-/-) or Vtn(RGE/RGE) mice undergo robust TGF-β-induced apoptosis. Plasminogen activator inhibitor-1 (PAI-1) sensitizes AECs to greater apoptosis by disrupting AEC engagement to vitronectin. Inhibition of integrin-associated signaling proteins augments AEC apoptosis. Mice with transgenic deletion of PAI-1 have less apoptosis after bleomycin, but deletion of vitronectin or disruption of the vitronectin RGD motif reverses this protection, suggesting that the proapoptotic function of PAI-1 is mediated through vitronectin inhibition. Collectively, these data suggest that integrin-matrix signaling is an important regulator of TGF-β-mediated AEC apoptosis and that PAI-1 functions as a natural regulator of this interaction. PMID:27106291

  15. CXCL9 Regulates TGF-β1 induced Epithelial to Mesenchymal Transition in Human Alveolar Epithelial Cells

    PubMed Central

    O’Beirne, Sarah L; Walsh, Sinead M; Fabre, Aurélie; Reviriego, Carlota; Worrell, Julie C; Counihan, Ian P; Lumsden, Robert V; Cramton-Barnes, Jennifer; Belperio, John A.; Donnelly, Seamas C; Boylan, Denise; Marchal-Somme, Joëlle; Kane, Rosemary; Keane, Michael P

    2016-01-01

    Epithelial to mesenchymal transition (EMT), whereby fully differentiated epithelial cells transition to a mesenchymal phenotype has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). CXCR3 and its ligands are recognized to play a protective role in pulmonary fibrosis. In this study, we investigated the presence and extent of EMT and CXCR3 expression in human IPF surgical lung biopsies and assessed whether CXCR3 and its ligand CXCL9 modulate EMT in alveolar epithelial cells. Coexpression of the epithelial maker thyroid transcription factor-1, and mesenchymal marker α-smooth muscle actin and CXCR3 expression was examined by immunohistochemical staining of IPF surgical lung biopsies. Epithelial and mesenchymal marker expression was examined by quantitative real-time PCR, Western blotting, and immunofluorescence in human alveolar epithelial (A549) cells treated with TGF-β1 and CXCL9, whilst Smad2, Smad3, and Smad7 expression and cellular localization examined by Western blotting. We found that significantly more cells were undergoing EMT in fibrotic versus normal areas of lung in IPF surgical lung biopsy samples. CXCR3 was expressed by type II pneumocytes and fibroblasts in fibrotic areas in close proximity to cells undergoing EMT. In vitro, CXCL9 abrogated TGF-β1 induced EMT. A decrease in TGF-β1 induced phosphorylation of Smad2 and Smad3 occurred with CXCL9 treatment. This was associated with increased shuttling of Smad7 from the nucleus to the cytoplasm where it inhibits Smad phosphorylation. This suggests a role for EMT in the pathogenesis of IPF and provides a novel mechanism for the inhibitory effects of CXCL9 on TGF-β1 induced EMT. PMID:26268659

  16. Pulmonary surfactant mitigates silver nanoparticle toxicity in human alveolar type-I-like epithelial cells.

    PubMed

    Sweeney, Sinbad; Leo, Bey Fen; Chen, Shu; Abraham-Thomas, Nisha; Thorley, Andrew J; Gow, Andrew; Schwander, Stephan; Zhang, Junfeng Jim; Shaffer, Milo S P; Chung, Kian Fan; Ryan, Mary P; Porter, Alexandra E; Tetley, Teresa D

    2016-09-01

    Accompanying increased commercial applications and production of silver nanomaterials is an increased probability of human exposure, with inhalation a key route. Nanomaterials that deposit in the pulmonary alveolar region following inhalation will interact firstly with pulmonary surfactant before they interact with the alveolar epithelium. It is therefore critical to understand the effects of human pulmonary surfactant when evaluating the inhalation toxicity of silver nanoparticles. In this study, we evaluated the toxicity of AgNPs on human alveolar type-I-like epithelial (TT1) cells in the absence and presence of Curosurf(®) (a natural pulmonary surfactant substitute), hypothesising that the pulmonary surfactant would act to modify toxicity. We demonstrated that 20nm citrate-capped AgNPs induce toxicity in human alveolar type I-like epithelial cells and, in agreement with our hypothesis, that pulmonary surfactant acts to mitigate this toxicity, possibly through reducing AgNP dissolution into cytotoxic Ag(+) ions. For example, IL-6 and IL-8 release by TT1 cells significantly increased 10.7- and 35-fold, respectively (P<0.01), 24h after treatment with 25μg/ml AgNPs. In contrast, following pre-incubation of AgNPs with Curosurf(®), this effect was almost completely abolished. We further determined that the mechanism of this toxicity is likely associated with Ag(+) ion release and lysosomal disruption, but not with increased reactive oxygen species generation. This study provides a critical understanding of the toxicity of AgNPs in target human alveolar type-I-like epithelial cells and the role of pulmonary surfactant in mitigating this toxicity. The observations reported have important implications for the manufacture and application of AgNPs, in particular for applications involving use of aerosolised AgNPs. PMID:27182651

  17. DA-Raf–dependent inhibition of the Ras-ERK signaling pathway in type 2 alveolar epithelial cells controls alveolar formation

    PubMed Central

    Watanabe-Takano, Haruko; Takano, Kazunori; Sakamoto, Akemi; Matsumoto, Kenji; Tokuhisa, Takeshi; Endo, Takeshi; Hatano, Masahiko

    2014-01-01

    Alveolar formation is coupled to the spatiotemporally regulated differentiation of alveolar myofibroblasts (AMYFs), which contribute to the morphological changes of interalveolar walls. Although the Ras-ERK signaling pathway is one of the key regulators for alveolar formation in developing lungs, the intrinsic molecular and cellular mechanisms underlying its role remain largely unknown. By analyzing the Ras-ERK signaling pathway during postnatal development of lungs, we have identified a critical role of DA-Raf1 (DA-Raf)—a dominant-negative antagonist for the Ras-ERK signaling pathway—in alveolar formation. DA-Raf–deficient mice displayed alveolar dysgenesis as a result of the blockade of AMYF differentiation. DA-Raf is predominantly expressed in type 2 alveolar epithelial cells (AEC2s) in developing lungs, and DA-Raf–dependent MEK1/2 inhibition in AEC2s suppresses expression of tissue inhibitor of matalloprotienase 4 (TIMP4), which prevents a subsequent proteolytic cascade matrix metalloproteinase (MMP)14–MMP2. Furthermore, MMP14–MMP2 proteolytic cascade regulates AMYF differentiation and alveolar formation. Therefore, DA-Raf–dependent inhibition of the Ras-ERK signaling pathway in AEC2s is required for alveolar formation via triggering MMP2 activation followed by AMYF differentiation. These findings reveal a pivotal role of the Ras-ERK signaling pathway in the dynamic regulation of alveolar development. PMID:24843139

  18. Anoctamin 1 dysregulation alters bronchial epithelial repair in cystic fibrosis.

    PubMed

    Ruffin, Manon; Voland, Mélanie; Marie, Solenne; Bonora, Monique; Blanchard, Elise; Blouquit-Laye, Sabine; Naline, Emmanuel; Puyo, Philippe; Le Rouzic, Philippe; Guillot, Loic; Corvol, Harriet; Clement, Annick; Tabary, Olivier

    2013-12-01

    Cystic fibrosis (CF) airway epithelium is constantly subjected to injury events due to chronic infection and inflammation. Moreover, abnormalities in CF airway epithelium repair have been described and contribute to the lung function decline seen in CF patients. In the last past years, it has been proposed that anoctamin 1 (ANO1), a Ca(2+)-activated Cl(-) channel, might offset the CFTR deficiency but this protein has not been characterized in CF airways. Interestingly, recent evidence indicates a role for ANO1 in cell proliferation and tumor growth. Our aims were to study non-CF and CF bronchial epithelial repair and to determine whether ANO1 is involved in airway epithelial repair. Here, we showed, with human bronchial epithelial cell lines and primary cells, that both cell proliferation and migration during epithelial repair are delayed in CF compared to non-CF cells. We then demonstrated that ANO1 Cl(-) channel activity was significantly decreased in CF versus non-CF cells. To explain this decreased Cl(-) channel activity in CF context, we compared ANO1 expression in non-CF vs. CF bronchial epithelial cell lines and primary cells, in lung explants from wild-type vs. F508del mice and non-CF vs. CF patients. In all these models, ANO1 expression was markedly lower in CF compared to non-CF. Finally, we established that ANO1 inhibition or overexpression was associated respectively with decreases and increases in cell proliferation and migration. In summary, our study demonstrates involvement of ANO1 decreased activity and expression in abnormal CF airway epithelial repair and suggests that ANO1 correction may improve this process. PMID:24080196

  19. Biophysical determinants of alveolar epithelial plasma membrane wounding associated with mechanical ventilation

    PubMed Central

    Hussein, Omar; Walters, Bruce; Stroetz, Randolph; Valencia, Paul; McCall, Deborah

    2013-01-01

    Mechanical ventilation may cause harm by straining lungs at a time they are particularly prone to injury from deforming stress. The objective of this study was to define the relative contributions of alveolar overdistension and cyclic recruitment and “collapse” of unstable lung units to membrane wounding of alveolar epithelial cells. We measured the interactive effects of tidal volume (VT), transpulmonary pressure (PTP), and of airspace liquid on the number of alveolar epithelial cells with plasma membrane wounds in ex vivo mechanically ventilated rat lungs. Plasma membrane integrity was assessed by propidium iodide (PI) exclusion in confocal images of subpleural alveoli. Cyclic inflations of normal lungs from zero end-expiratory pressure to 40 cmH2O produced VT values of 56.9 ± 3.1 ml/kg and were associated with 0.12 ± 0.12 PI-positive cells/alveolus. A preceding tracheal instillation of normal saline (3 ml) reduced VT to 49.1 ± 6 ml/kg but was associated with a significantly greater number of wounded alveolar epithelial cells (0.52 ± 0.16 cells/alveolus; P < 0.01). Mechanical ventilation of completely saline-filled lungs with saline (VT = 52 ml/kg) to pressures between 10 and 15 cmH2O was associated with the least number of wounded epithelial cells (0.02 ± 0.02 cells/alveolus; P < 0.01). In mechanically ventilated, partially saline-filled lungs, the number of wounded cells increased substantially with VT, but, once VT was accounted for, wounding was independent of maximal PTP. We found that interfacial stress associated with the generation and destruction of liquid bridges in airspaces is the primary biophysical cell injury mechanism in mechanically ventilated lungs. PMID:23997173

  20. Biophysical determinants of alveolar epithelial plasma membrane wounding associated with mechanical ventilation.

    PubMed

    Hussein, Omar; Walters, Bruce; Stroetz, Randolph; Valencia, Paul; McCall, Deborah; Hubmayr, Rolf D

    2013-10-01

    Mechanical ventilation may cause harm by straining lungs at a time they are particularly prone to injury from deforming stress. The objective of this study was to define the relative contributions of alveolar overdistension and cyclic recruitment and "collapse" of unstable lung units to membrane wounding of alveolar epithelial cells. We measured the interactive effects of tidal volume (VT), transpulmonary pressure (PTP), and of airspace liquid on the number of alveolar epithelial cells with plasma membrane wounds in ex vivo mechanically ventilated rat lungs. Plasma membrane integrity was assessed by propidium iodide (PI) exclusion in confocal images of subpleural alveoli. Cyclic inflations of normal lungs from zero end-expiratory pressure to 40 cmH2O produced VT values of 56.9 ± 3.1 ml/kg and were associated with 0.12 ± 0.12 PI-positive cells/alveolus. A preceding tracheal instillation of normal saline (3 ml) reduced VT to 49.1 ± 6 ml/kg but was associated with a significantly greater number of wounded alveolar epithelial cells (0.52 ± 0.16 cells/alveolus; P < 0.01). Mechanical ventilation of completely saline-filled lungs with saline (VT = 52 ml/kg) to pressures between 10 and 15 cmH2O was associated with the least number of wounded epithelial cells (0.02 ± 0.02 cells/alveolus; P < 0.01). In mechanically ventilated, partially saline-filled lungs, the number of wounded cells increased substantially with VT, but, once VT was accounted for, wounding was independent of maximal PTP. We found that interfacial stress associated with the generation and destruction of liquid bridges in airspaces is the primary biophysical cell injury mechanism in mechanically ventilated lungs. PMID:23997173

  1. Generation of alveolar epithelial spheroids via isolated progenitor cells from human pluripotent stem cells.

    PubMed

    Gotoh, Shimpei; Ito, Isao; Nagasaki, Tadao; Yamamoto, Yuki; Konishi, Satoshi; Korogi, Yohei; Matsumoto, Hisako; Muro, Shigeo; Hirai, Toyohiro; Funato, Michinori; Mae, Shin-Ichi; Toyoda, Taro; Sato-Otsubo, Aiko; Ogawa, Seishi; Osafune, Kenji; Mishima, Michiaki

    2014-09-01

    No methods for isolating induced alveolar epithelial progenitor cells (AEPCs) from human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) have been reported. Based on a study of the stepwise induction of alveolar epithelial cells (AECs), we identified carboxypeptidase M (CPM) as a surface marker of NKX2-1(+) "ventralized" anterior foregut endoderm cells (VAFECs) in vitro and in fetal human and murine lungs. Using SFTPC-GFP reporter hPSCs and a 3D coculture system with fetal human lung fibroblasts, we showed that CPM(+) cells isolated from VAFECs differentiate into AECs, demonstrating that CPM is a marker of AEPCs. Moreover, 3D coculture differentiation of CPM(+) cells formed spheroids with lamellar-body-like structures and an increased expression of surfactant proteins compared with 2D differentiation. Methods to induce and isolate AEPCs using CPM and consequently generate alveolar epithelial spheroids would aid human pulmonary disease modeling and regenerative medicine. PMID:25241738

  2. Pulmonary contusion induces alveolar type 2 epithelial cell apoptosis: role of alveolar macrophages and neutrophils.

    PubMed

    Seitz, Daniel H; Perl, Mario; Mangold, Stefanie; Neddermann, Anne; Braumüller, Sonja T; Zhou, Shaoixa; Bachem, Max G; Huber-Lang, Markus S; Knöferl, Markus W

    2008-11-01

    Alveolar type 2 (AT-2) cell apoptosis is an important mechanism during lung inflammation, lung injury, and regeneration. Blunt chest trauma has been shown to activate inflammatory cells such as alveolar macrophages (AMs) or neutrophils (polymorphonuclear granulocytes [PMNs]), resulting in an inflammatory response. The present study was performed to determine the capacity of different components/cells of the alveolar compartment (AMs, PMNs, or bronchoalveolar lavage [BAL] fluids) to induce apoptosis in AT-2 cells following blunt chest trauma. To study this, male Sprague-Dawley rats were subjected to either sham procedure or blunt chest trauma induced by a single blast wave. Various time points after injury (6 h to 7 d), the lungs were analyzed by immunohistochemistry, for AT-2 cells, or with antibodies directed against caspase 3, caspase 8, Fas, Fas ligand (FasL), BAX, and BCL-2. Bronchoalveolar lavage concentrations of TNF-alpha, IL-1beta, and soluble FasL were determined by enzyme-linked immunosorbent assay. Furthermore, cultures of AT-2 cells isolated from healthy rats were incubated with supernatants of AMs, PMNs, or BAL fluids obtained from either trauma or sham-operated animals in the presence or absence of oxidative stress. Annexin V staining or TUNEL (terminal deoxynucleotidyl transferase) assay was used to detect apoptotic AT-2 cells. Histological evaluation revealed that the total number of AT-2 cells was significantly reduced at 48 h following trauma. Fas, FasL, active caspase 8, and active caspase 3 were markedly up-regulated in AT-2 cells after chest trauma. BAX and BCL-2 did not show any significant changes between sham and trauma. IL-1beta, but not TNF-alpha, levels were markedly increased at 24 h after the injury, and soluble FasL concentrations were significantly enhanced at 6, 12, 24, and 48 h after the insult. Apoptosis of AT-2 cells incubated with supernatants from cultured AMs, isolated at 48 h following chest trauma was markedly increased when

  3. Role of endoplasmic reticulum stress in epithelial-mesenchymal transition of alveolar epithelial cells: effects of misfolded surfactant protein.

    PubMed

    Zhong, Qian; Zhou, Beiyun; Ann, David K; Minoo, Parviz; Liu, Yixin; Banfalvi, Agnes; Krishnaveni, Manda S; Dubourd, Mickael; Demaio, Lucas; Willis, Brigham C; Kim, Kwang-Jin; duBois, Roland M; Crandall, Edward D; Beers, Michael F; Borok, Zea

    2011-09-01

    Endoplasmic reticulum (ER) stress has been implicated in alveolar epithelial type II (AT2) cell apoptosis in idiopathic pulmonary fibrosis. We hypothesized that ER stress (either chemically induced or due to accumulation of misfolded proteins) is also associated with epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs). ER stress inducers, thapsigargin (TG) or tunicamycin (TN), increased expression of ER chaperone, Grp78, and spliced X-box binding protein 1, decreased epithelial markers, E-cadherin and zonula occludens-1 (ZO-1), increased the myofibroblast marker, α-smooth muscle actin (α-SMA), and induced fibroblast-like morphology in both primary AECs and the AT2 cell line, RLE-6TN, consistent with EMT. Overexpression of the surfactant protein (SP)-C BRICHOS mutant SP-C(ΔExon4) in A549 cells increased Grp78 and α-SMA and disrupted ZO-1 distribution, and, in primary AECs, SP-C(ΔExon4) induced fibroblastic-like morphology, decreased ZO-1 and E-cadherin and increased α-SMA, mechanistically linking ER stress associated with mutant SP to fibrosis through EMT. Whereas EMT was evident at lower concentrations of TG or TN, higher concentrations caused apoptosis. The Src inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4]pyramidine) (PP2), abrogated EMT associated with TN or TG in primary AECs, whereas overexpression of SP-C(ΔExon4) increased Src phosphorylation, suggesting a common mechanism. Furthermore, increased Grp78 immunoreactivity was observed in AT2 cells of mice after bleomycin injury, supporting a role for ER stress in epithelial abnormalities in fibrosis in vivo. These results demonstrate that ER stress induces EMT in AECs, at least in part through Src-dependent pathways, suggesting a novel role for ER stress in fibroblast accumulation in pulmonary fibrosis. PMID:21169555

  4. Wound repair: role of immune–epithelial interactions

    PubMed Central

    Leoni, G; Neumann, P-A; Sumagin, R; Denning, TL; Nusrat, A

    2016-01-01

    The epithelium serves as a highly selective barrier at mucosal surfaces. Upon injury, epithelial wound closure is orchestrated by a series of events that emanate from the epithelium itself as well as by the temporal recruitment of immune cells into the wound bed. Epithelial cells adjoining the wound flatten out, migrate, and proliferate to rapidly cover denuded surfaces and re-establish mucosal homeostasis. This process is highly regulated by proteins and lipids, proresolving mediators such as Annexin A1 protein and resolvins released into the epithelial milieu by the epithelium itself and infiltrating innate immune cells including neutrophils and macrophages. Failure to achieve these finely tuned processes is observed in chronic inflammatory diseases that are associated with non-healing wounds. An improved understanding of mechanisms that mediate repair is important in the development of therapeutics aimed to promote mucosal wound repair. PMID:26174765

  5. Cyclic stretch induces alveolar epithelial barrier dysfunction via calpain-mediated degradation of p120-catenin.

    PubMed

    Wang, Yuelan; Minshall, Richard D; Schwartz, David E; Hu, Guochang

    2011-08-01

    Lung hyperinflation is known to be an important contributing factor in the pathogenesis of ventilator-induced lung injury. Mechanical stretch causes epithelial barrier dysfunction and an increase in alveolar permeability, although the precise mechanisms have not been completely elucidated. p120-catenin is an adherens junction-associated protein that regulates cell-cell adhesion. In this study, we determined the role of p120-catenin in cyclic stretch-induced alveolar epithelial barrier dysfunction. Cultured alveolar epithelial cells (MLE-12) were subjected to uniform cyclic (0.5 Hz) biaxial stretch from 0 to 8 or 20% change in surface area for 0, 1, 2, or 4 h. At the end of the experiments, cells were lysed to determine p120-catenin expression by Western blot analysis. Immunofluorescence staining of p120-catenin and F-actin was performed to assess the integrity of monolayers and interepithelial gap formation. Compared with unstretched control cells, 20% stretch caused a significant loss in p120-catenin expression, which was coupled to interepithelial gap formation. p120-Catenin knockdown with small interfering RNA (siRNA) dose dependently increased stretch-induced gap formation, whereas overexpression of p120-catenin abolished stretch-induced gap formation. Furthermore, pharmacological calpain inhibition or depletion of calpain-1 with a specific siRNA prevented p120-catenin loss and subsequent stretch-induced gap formation. Our findings demonstrate that p120-catenin plays a critical protective role in cyclic stretch-induced alveolar barrier dysfunction, and, thus, maintenance of p120-catenin expression may be a novel therapeutic strategy for the prevention and treatment of ventilator-induced lung injury. PMID:21571907

  6. Correlation of vermilion symmetry to alveolar cleft defect in unilateral cleft lip repair.

    PubMed

    Bonanthaya, K; Rao, D D; Shetty, P; Uguru, C

    2016-06-01

    Asymmetry is a major problem in repaired unilateral cleft lip (UCL). One of the important manifestations of this is the asymmetry of the vermilion. The aim of this study was to correlate the severity of the asymmetry in the vermilion to the size of the alveolar defect. Twenty patients aged between 6 and 18 months with complete unilateral cleft lip, alveolus, and palate were included. An impression of each patient's alveolus at the time of cheiloplasty was taken using silicon rubber base material, and a study cast was prepared. The width of the cleft alveolus was measured on these casts using a transparent grid. Frontal photographs were taken at 6 months postoperative and vermilion symmetry was measured as the ratio between the cleft and non-cleft sides. The results obtained in this study showed a direct correlation between the size of the alveolar defect and the vermilion symmetry in repaired UCL. The wider the cleft alveolus and greater the antero-posterior discrepancy, the greater is the vermilion asymmetry. The asymmetry of the vermilion in UCL after repair is directly dependent on the size of the alveolar defect. The alveolar discrepancy causes 'in-rolling' of the vermilion on the cleft side and affects the vermilion symmetry. PMID:26754270

  7. Differentiated kidney epithelial cells repair injured proximal tubule.

    PubMed

    Kusaba, Tetsuro; Lalli, Matthew; Kramann, Rafael; Kobayashi, Akio; Humphreys, Benjamin D

    2014-01-28

    Whether kidney proximal tubule harbors a scattered population of epithelial stem cells is a major unsolved question. Lineage-tracing studies, histologic characterization, and ex vivo functional analysis results conflict. To address this controversy, we analyzed the lineage and clonal behavior of fully differentiated proximal tubule epithelial cells after injury. A CreER(T2) cassette was knocked into the sodium-dependent inorganic phosphate transporter SLC34a1 locus, which is expressed only in differentiated proximal tubule. Tamoxifen-dependent recombination was absolutely specific to proximal tubule. Clonal analysis after injury and repair showed that the bulk of labeled cells proliferate after injury with increased clone size after severe compared with mild injury. Injury to labeled proximal tubule epithelia induced expression of CD24, CD133, vimentin, and kidney-injury molecule-1, markers of putative epithelial stem cells in the human kidney. Similar results were observed in cultured proximal tubules, in which labeled clones proliferated and expressed dedifferentiation and injury markers. When mice with completely labeled kidneys were subject to injury and repair there was no dilution of fate marker despite substantial proliferation, indicating that unlabeled progenitors do not contribute to kidney repair. During nephrogenesis and early kidney growth, single proximal tubule clones expanded, suggesting that differentiated cells also contribute to tubule elongation. These findings provide no evidence for an intratubular stem-cell population, but rather indicate that terminally differentiated epithelia reexpress apparent stem-cell markers during injury-induced dedifferentiation and repair. PMID:24127583

  8. [Binase penetration into alveolar epithelial cells does not induce cell death].

    PubMed

    Cabrera Fuentes, H A; Kalacheva, N V; Mukhametshina, R T; Zelenichin, P V; Kolpakov, A I; Barreto, G; Praĭssner, K T; Il'inskaia, O N

    2012-01-01

    Microbial ribonucleases possess a broad spectra of biological activities, demonstrating stimulating properties at low concentrations and cytotoxicity and genotoxicity at high concentrations. The mechanisms of their penetration into the cells are not clear so far. This research is aimed to the study of Bacillus intermedius RNase (binase) penetration in alveolar lung epithelial cells--pneumocytes of type II. Using immunofluorescence we have shown for the first time have internalization of binase by primary non-differentiated pneumocytes ATII. The enzyme did not penetrate in pneumocytes MLE-12, which also derived from type II cells. However, binase was cytotoxic towards tumor MLE-12 cells, but not ATII cells. The obtained results testified the higher sensitivity of tumor cells towards binase compared with normal cells, and also showed that penetration of the enzyme into alveolar cells did not directly correlated with the cell death. PMID:22856132

  9. Establishment and Evaluation of a Stable Cattle Type II Alveolar Epithelial Cell Line

    PubMed Central

    Su, Feng; Liu, Xin; Liu, Guanghui; Yu, Yuan; Wang, Yongsheng; Jin, Yaping; Hu, Guangdong; Hua, Song; Zhang, Yong

    2013-01-01

    Macrophages and dendritic cells are recognized as key players in the defense against mycobacterial infection. Recent research has confirmed that alveolar epithelial cells (AECs) also play important roles against mycobacterium infections. Thus, establishing a stable cattle AEC line for future endogenous immune research on bacterial invasion is necessary. In the present study, we first purified and immortalized type II AECs (AEC II cells) by transfecting them with a plasmid containing the human telomerase reverse trancriptase gene. We then tested whether or not the immortalized cells retained the basic physiological properties of primary AECs by reverse-transcription polymerase chain reaction and Western blot. Finally, we tested the secretion capacity of immortalized AEC II cells upon stimulation by bacterial invasion. The cattle type II alveolar epithelial cell line (HTERT-AEC II) that we established retained lung epithelial cell characteristics: the cells were positive for surfactants A and B, and they secreted tumor necrosis factor-α and interleukin-6 in response to bacterial invasion. Thus, the cell line we established is a potential tool for research on the relationship between AECs and Mycobacterium tuberculosis. PMID:24086682

  10. Silver nanowire interactions with primary human alveolar type-II epithelial cell secretions: contrasting bioreactivity with human alveolar type-I and type-II epithelial cells.

    PubMed

    Sweeney, Sinbad; Theodorou, Ioannis G; Zambianchi, Marta; Chen, Shu; Gow, Andrew; Schwander, Stephan; Zhang, Junfeng Jim; Chung, Kian Fan; Shaffer, Milo S P; Ryan, Mary P; Porter, Alexandra E; Tetley, Teresa D

    2015-06-21

    Inhaled nanoparticles have a high deposition rate in the alveolar units of the deep lung. The alveolar epithelium is composed of type-I and type-II epithelial cells (ATI and ATII respectively) and is bathed in pulmonary surfactant. The effect of native human ATII cell secretions on nanoparticle toxicity is not known. We investigated the cellular uptake and toxicity of silver nanowires (AgNWs; 70 nm diameter, 1.5 μm length) with human ATI-like cells (TT1), in the absence or presence of Curosurf® (a natural porcine pulmonary surfactant with a low amount of protein) or harvested primary human ATII cell secretions (HAS; containing both the complete lipid as well as the full protein complement of human pulmonary surfactant i.e. SP-A, SP-B, SP-C and SP-D). We hypothesised that Curosurf® or HAS would confer improved protection for TT1 cells, limiting the toxicity of AgNWs. In agreement with our hypothesis, HAS reduced the inflammatory and reactive oxygen species (ROS)-generating potential of AgNWs with exposed TT1 cells. For example, IL-8 release and ROS generation was reduced by 38% and 29%, respectively, resulting in similar levels to that of the non-treated controls. However in contrast to our hypothesis, Curosurf® had no effect. We found a significant reduction in AgNW uptake by TT1 cells in the presence of HAS but not Curosurf. Furthermore, we show that the SP-A and SP-D are likely to be involved in this process as they were found to be specifically bound to the AgNWs. While ATI cells appear to be protected by HAS, evidence suggested that ATII cells, despite no uptake, were vulnerable to AgNW exposure (indicated by increased IL-8 release and ROS generation and decreased intracellular SP-A levels one day post-exposure). This study provides unique findings that may be important for the study of lung epithelial-endothelial translocation of nanoparticles in general and associated toxicity within the alveolar unit. PMID:25996248

  11. Silver nanowire interactions with primary human alveolar type-II epithelial cell secretions: contrasting bioreactivity with human alveolar type-I and type-II epithelial cells

    PubMed Central

    Sweeney, Sinbad; Theodorou, Ioannis G.; Zambianchi, Martina; Chen, Shu; Gow, Andrew; Schwander, Stephan; Zhang, Junfeng (Jim); Chung, Kian Fan; Shaffer, Milo S.; Ryan, Mary P.; Porter, Alexandra E.; Tetley, Teresa D.

    2015-01-01

    Inhaled nanoparticles have a high deposition rate in the alveolar units of the deep lung. The alveolar epithelium is composed of type-I and type-II epithelial cells (ATI and ATII respectively) and is bathed in pulmonary surfactant. The effect of native human ATII cell secretions on nanoparticle toxicity is not known. We investigated the cellular uptake and toxicity of silver nanowires (AgNWs; 70 nm diameter, 1.5 μm length) with human ATI-like cells (TT1), in the absence or presence of Curosurf® (a natural porcine pulmonary surfactant with a low amount of protein) or harvested primary human ATII cell secretions (HAS; containing both the complete lipid as well as the full protein complement of human pulmonary surfactant i.e. SP-A, SP-B, SP-C and SP-D). We hypothesised that Curosurf® or HAS would confer improved protection for TT1 cells, limiting the toxicity of AgNWs. In agreement with our hypothesis, HAS reduced the inflammatory and reactive oxygen species (ROS)-generating potential of AgNWs with exposed TT1 cells. For example, IL-8 release and ROS generation was reduced by 38% and 29%, respectively, resulting in similar levels to that of the non-treated controls. However in contrast to our hypothesis, Curosurf® had no effect. We found a significant reduction in AgNW uptake by TT1 cells in the presence of HAS but not Curosurf. Furthermore, we show that the SP-A and SP-D are likely to be involved in this process as they were found to be specifically bound to the AgNWs. While ATI cells appear to be protected by HAS, evidence suggested that ATII cells, despite no uptake, were vulnerable to AgNW exposure (indicated by increased IL-8 release and ROS generation and decreased intracellular SP-A levels one day post-exposure). This study provides unique findings that may be important for the study of lung epithelial-endothelial translocation of nanoparticles in general and associated toxicity within the alveolar unit. PMID:25996248

  12. Establishment of immortalized alveolar type II epithelial cell lines from adult rats.

    PubMed

    Driscoll, K E; Carter, J M; Iype, P T; Kumari, H L; Crosby, L L; Aardema, M J; Isfort, R J; Cody, D; Chestnut, M H; Burns, J L

    1995-01-01

    We developed methodology to isolate and culture rat alveolar Type II cells under conditions that preserved their proliferative capacity, and applied lipofection to introduce an immortalizing gene into the cells. Briefly, the alveolar Type II cells were isolated from male F344 rats using airway perfusion with a pronase solution followed by incubation for 30 min at 37 degrees C. Cells obtained by pronase digestion were predominantly epithelial in morphology and were positive for Papanicolaou and alkaline phosphatase staining. These cells could be maintained on an extracellular matrix of fibronectin and Type IV collagen in a low serum, insulin-supplemented Ham's F12 growth medium for four to five passages. Rat alveolar epithelial cells obtained by this method were transformed with the SV40-T antigen gene and two immortalized cell lines (RLE-6T and RLE-6TN) were obtained. The RLE-6T line exhibits positive nuclear immunostaining for the SV40-T antigen and the RLE-6TN line does not. PCR analysis of genomic DNA from the RLE-6T and RLE-6TN cells demonstrated the T-antigen gene was present only in the RLE-6T line indicating the RLE-6TN line is likely derived from a spontaneous transformant. After more than 50 population doublings, the RLE-6T cells stained positive for cytokeratin, possessed alkaline phosphatase activity, and contained lipid-containing inclusion bodies (phosphine 3R staining); all characteristics of alveolar Type II cells. The RLE-6TN cells exhibited similar characteristics except they did not express alkaline phosphatase activity. Early passage RLE-6T and 6TN cells showed a near diploid chromosome number.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8528500

  13. Emodin enhances alveolar epithelial barrier function in rats with experimental acute pancreatitis

    PubMed Central

    Xia, Xian-Ming; Wang, Fang-Yu; Wang, Zhen-Kai; Wan, Hai-Jun; Xu, Wen-An; Lu, Heng

    2010-01-01

    AIM: To investigate the effect of emodin on expression of claudin-4, claudin-5 and occludin, as well as the alveolar epithelial barrier in rats with pancreatitis induced by sodium taurocholate. METHODS: Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Emodin was injected via the external jugular vein 3 h after induction of acute pancreatitis. Rats from sham operation group and acute pancreatitis group were injected with normal saline (an equivalent volume as emodin) at the same time point. Samples of lung and serum were obtained 6 h after drug administration. Pulmonary morphology was examined with HE staining. Pulmonary edema was estimated by measuring water content in lung tissue samples. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) level were measured by enzyme-linked immunospecific assay. Serum amylase and pulmonary myeloperoxidase (MPO) activity were detected by spectrophotometry. Alveolar epithelial barrier was assessed by pulmonary dye extravasation. Expression of claudin-4, claudin-5 and occludin in lung tissue samples was examined by immunohistology, quantitative real-time reverse transcription polymerase chain reaction and Western blotting analysis, respectively. RESULTS: Pancreatitis-associated lung injury was characterized by pulmonary edema, leukocyte infiltration, alveolar collapse, and elevated serum amylase level. The pulmonary damage, pulmonary pathological scores, serum amylase and MPO activity, TNF-α and IL-6 levels, and wet/dry ratio were decreased in rats after treatment with emodin. Immunostaining of claudin-4, claudin-5 and occludin was detected in lung tissue samples from rats in sham operation group, which was distributed in alveolar epithelium, vascular endothelium, and bronchial epithelium, respectively. The mRNA and protein expression levels of claudin-4, claudin-5 and occludin in lung tissue samples were markedly decreased, the expression level of

  14. TRPM2 channels in alveolar epithelial cells mediate bleomycin-induced lung inflammation.

    PubMed

    Yonezawa, Ryo; Yamamoto, Shinichiro; Takenaka, Miki; Kage, Yukiko; Negoro, Takaharu; Toda, Takahiro; Ohbayashi, Masayuki; Numata, Tomohiro; Nakano, Yasuko; Yamamoto, Toshinori; Mori, Yasuo; Ishii, Masakazu; Shimizu, Shunichi

    2016-01-01

    Lung inflammation is a major adverse effect of therapy with the antitumor drug bleomycin (BLM). Transient receptor potential melastatin 2 (TRPM2) is a Ca(2+)-permeable channel that is activated by oxidative stress through the production of ADP-ribose. We herein investigated whether TRPM2 channels contributed to BLM-induced lung inflammation. The intratracheal instillation of BLM into wild-type (WT) mice increased the number of polymorphonuclear leukocytes (PMNs) and inflammatory cytokine levels in the lung. Increases in inflammatory markers in WT mice were markedly reduced in trpm2 knockout (KO) mice, which demonstrated that the activation of TRPM2 channels was involved in BLM-induced lung inflammation. The expression of TRPM2 mRNA was observed in alveolar macrophages, alveolar epithelial cells, and lung fibroblasts. Actually, TRPM2 protein was expressed in lung tissues. Of these, TRPM2 channels in epithelial cells were activated by the addition of H2O2 following a BLM pretreatment, resulting in the secretion of macrophage inflammatory protein-2 (MIP-2). The H2O2-induced activation of TRPM2 by the BLM pretreatment was blocked by the poly(ADP-ribose) polymerase (PARP) inhibitors PJ34 and 3-aminobenzamide. The accumulation of poly(ADP-ribose) in the nucleus, a marker for ADP-ribose production, was strongly induced by H2O2 following the BLM pretreatment. Furthermore, administration of PRAP inhibitors into WT mice markedly reduced recruitment of inflammatory cells and MIP-2 secretion induced by BLM instillation. These results suggest that the induction of MIP-2 secretion through the activation of TRPM2 channels in alveolar epithelial cells is an important mechanism in BLM-induced lung inflammation, and the TRPM2 activation is likely to be mediated by ADP-ribose production via PARP pathway. TRPM2 channels may be new therapeutic target for BLM-induced lung inflammation. PMID:26600069

  15. Role of stretch on tight junction structure in alveolar epithelial cells.

    PubMed

    Cavanaugh, K J; Oswari, J; Margulies, S S

    2001-11-01

    Previous studies have demonstrated that high tidal volumes can cause interstitial and alveolar edema, with degradation of pulmonary epithelial barrier integrity. Separate studies have shown that F-actin disruption and decreased intracellular ATP (ATP(i)) levels in the nonpulmonary epithelium can increase tight junction (TJ) permeability. We hypothesized that large epithelial stretch perturbs ATP(i) and actin architecture, each of which adversely affects TJ structure, and thus increases TJ permeability. Primary alveolar epithelial cells were subjected to a uniform 25% or 37% change in surface area (DeltaSA), cyclic biaxial stretch (15 cycles/min) for 1 h, or treated with either glycolytic metabolic inhibitors or cytoskeletal disrupting agents. Unstretched, untreated cells served as controls. Changes in the TJ proteins occludin and ZO-1 were determined by immunocytochemical evaluation. A stretch amplitude of 25% DeltaSA did not produce any significant cytologic changes compared with controls, but an amplitude of 37% DeltaSA stretch resulted in significant decreases in the intensity of the peripheral occludin band, the degree of cell-cell attachment (CCA), and total cellular occludin content. ATP depletion significantly diminished the occludin band intensity and decreased CCA. Actin disruption did not affect TJ protein band intensities (although the occludin distribution became punctate) but altered CCA. Untreated cells stretched cyclically at 25% or 50% DeltaSA for 1 h had significantly decreased ATP(i) compared with unstretched controls. These results suggest that stretch-induced ATP(i) reduction and actin perturbation disrupt TJ structure and CCA, which may lead to the alveolar flooding associated with high tidal volumes. PMID:11713100

  16. Silver nanowire interactions with primary human alveolar type-II epithelial cell secretions: contrasting bioreactivity with human alveolar type-I and type-II epithelial cells

    NASA Astrophysics Data System (ADS)

    Sweeney, Sinbad; Theodorou, Ioannis G.; Zambianchi, Marta; Chen, Shu; Gow, Andrew; Schwander, Stephan; Zhang, Junfeng (Jim); Chung, Kian Fan; Shaffer, Milo S. P.; Ryan, Mary P.; Porter, Alexandra E.; Tetley, Teresa D.

    2015-06-01

    Inhaled nanoparticles have a high deposition rate in the alveolar units of the deep lung. The alveolar epithelium is composed of type-I and type-II epithelial cells (ATI and ATII respectively) and is bathed in pulmonary surfactant. The effect of native human ATII cell secretions on nanoparticle toxicity is not known. We investigated the cellular uptake and toxicity of silver nanowires (AgNWs; 70 nm diameter, 1.5 μm length) with human ATI-like cells (TT1), in the absence or presence of Curosurf® (a natural porcine pulmonary surfactant with a low amount of protein) or harvested primary human ATII cell secretions (HAS; containing both the complete lipid as well as the full protein complement of human pulmonary surfactant i.e. SP-A, SP-B, SP-C and SP-D). We hypothesised that Curosurf® or HAS would confer improved protection for TT1 cells, limiting the toxicity of AgNWs. In agreement with our hypothesis, HAS reduced the inflammatory and reactive oxygen species (ROS)-generating potential of AgNWs with exposed TT1 cells. For example, IL-8 release and ROS generation was reduced by 38% and 29%, respectively, resulting in similar levels to that of the non-treated controls. However in contrast to our hypothesis, Curosurf® had no effect. We found a significant reduction in AgNW uptake by TT1 cells in the presence of HAS but not Curosurf. Furthermore, we show that the SP-A and SP-D are likely to be involved in this process as they were found to be specifically bound to the AgNWs. While ATI cells appear to be protected by HAS, evidence suggested that ATII cells, despite no uptake, were vulnerable to AgNW exposure (indicated by increased IL-8 release and ROS generation and decreased intracellular SP-A levels one day post-exposure). This study provides unique findings that may be important for the study of lung epithelial-endothelial translocation of nanoparticles in general and associated toxicity within the alveolar unit.Inhaled nanoparticles have a high deposition rate in

  17. Epithelial injury and repair in airways diseases.

    PubMed

    Grainge, Christopher L; Davies, Donna E

    2013-12-01

    Asthma is a common chronic disease characterized by variable respiratory distress with underlying airway inflammation and airflow obstruction. The incidence of asthma has risen inexorably over the past 50 years, suggesting that environmental factors are important in its etiology. All inhaled environmental stimuli interact with the lung at the respiratory epithelium, and it is a testament to the effectiveness of the airway innate defenses that the majority of inhaled substances are cleared without the need to elicit an inflammatory response. However, once this barrier is breached, effective communication with immune and inflammatory cells is required to protect the internal milieu of the lung. In asthma, the respiratory epithelium is known to be structurally and functionally abnormal. Structurally, the epithelium shows evidence of damage and has more mucus-producing cells than normal airways. Functionally, the airway epithelial barrier can be more permeable and more sensitive to oxidants and show a deficient innate immune response to respiratory virus infection compared with that in normal individuals. The potential of a susceptible epithelium and the underlying mesenchyme to create a microenvironment that enables deviation of immune and inflammatory responses to external stimuli may be crucial in the development and progression of asthma. In this review, we consider three important groups of environmental stimuli on the epithelium in asthma: oxidants, such as environmental pollution and acetaminophen; viruses, including rhinovirus; and agents that cause barrier disruption, such as house dust mite allergens. The pathology associated with each stimulus is considered, and potential future treatments arising from research on their effects are presented. PMID:24297122

  18. Role of Endoplasmic Reticulum Stress in Epithelial–Mesenchymal Transition of Alveolar Epithelial Cells

    PubMed Central

    Zhong, Qian; Zhou, Beiyun; Ann, David K.; Minoo, Parviz; Liu, Yixin; Banfalvi, Agnes; Krishnaveni, Manda S.; Dubourd, Mickael; Demaio, Lucas; Willis, Brigham C.; Kim, Kwang-Jin; duBois, Roland M.; Crandall, Edward D.; Beers, Michael F.

    2011-01-01

    Endoplasmic reticulum (ER) stress has been implicated in alveolar epithelial type II (AT2) cell apoptosis in idiopathic pulmonary fibrosis. We hypothesized that ER stress (either chemically induced or due to accumulation of misfolded proteins) is also associated with epithelial–mesenchymal transition (EMT) in alveolar epithelial cells (AECs). ER stress inducers, thapsigargin (TG) or tunicamycin (TN), increased expression of ER chaperone, Grp78, and spliced X-box binding protein 1, decreased epithelial markers, E-cadherin and zonula occludens–1 (ZO-1), increased the myofibroblast marker, α–smooth muscle actin (α-SMA), and induced fibroblast-like morphology in both primary AECs and the AT2 cell line, RLE-6TN, consistent with EMT. Overexpression of the surfactant protein (SP)–C BRICHOS mutant SP-CΔExon4 in A549 cells increased Grp78 and α-SMA and disrupted ZO-1 distribution, and, in primary AECs, SP-CΔExon4 induced fibroblastic-like morphology, decreased ZO-1 and E-cadherin and increased α-SMA, mechanistically linking ER stress associated with mutant SP to fibrosis through EMT. Whereas EMT was evident at lower concentrations of TG or TN, higher concentrations caused apoptosis. The Src inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4]pyramidine) (PP2), abrogated EMT associated with TN or TG in primary AECs, whereas overexpression of SP-CΔExon4 increased Src phosphorylation, suggesting a common mechanism. Furthermore, increased Grp78 immunoreactivity was observed in AT2 cells of mice after bleomycin injury, supporting a role for ER stress in epithelial abnormalities in fibrosis in vivo. These results demonstrate that ER stress induces EMT in AECs, at least in part through Src-dependent pathways, suggesting a novel role for ER stress in fibroblast accumulation in pulmonary fibrosis. PMID:21169555

  19. FXYD1 negatively regulates Na(+)/K(+)-ATPase activity in lung alveolar epithelial cells.

    PubMed

    Wujak, Łukasz A; Blume, Anna; Baloğlu, Emel; Wygrecka, Małgorzata; Wygowski, Jegor; Herold, Susanne; Mayer, Konstantin; Vadász, István; Besuch, Petra; Mairbäurl, Heimo; Seeger, Werner; Morty, Rory E

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is clinical syndrome characterized by decreased lung fluid reabsorption, causing alveolar edema. Defective alveolar ion transport undertaken in part by the Na(+)/K(+)-ATPase underlies this compromised fluid balance, although the molecular mechanisms at play are not understood. We describe here increased expression of FXYD1, FXYD3 and FXYD5, three regulatory subunits of the Na(+)/K(+)-ATPase, in the lungs of ARDS patients. Transforming growth factor (TGF)-β, a pathogenic mediator of ARDS, drove increased FXYD1 expression in A549 human lung alveolar epithelial cells, suggesting that pathogenic TGF-β signaling altered Na(+)/K(+)-ATPase activity in affected lungs. Lentivirus-mediated delivery of FXYD1 and FXYD3 allowed for overexpression of both regulatory subunits in polarized H441 cell monolayers on an air/liquid interface. FXYD1 but not FXYD3 overexpression inhibited amphotericin B-sensitive equivalent short-circuit current in Ussing chamber studies. Thus, we speculate that FXYD1 overexpression in ARDS patient lungs may limit Na(+)/K(+)-ATPase activity, and contribute to edema persistence. PMID:26410457

  20. Osteogenic Differentiation of Human Amniotic Epithelial Cells and Its Application in Alveolar Defect Restoration

    PubMed Central

    Jiawen, Si; Jianjun, Zhang; Jiewen, Dai; Dedong, Yu; Hongbo, Yu; Jun, Shi; Xudong, Wang; Shen, Steve G.F.

    2014-01-01

    The present study investigated the detailed in vitro osteogenic differentiation process and in vivo bone regenerative property of human amniotic epithelial cells (hAECs). The in vitro osteogenic differentiation process of hAECs was evaluated by biochemical staining, real-time polymerase chain reaction, and immunofluorescence. Next, β-tricalcium phosphate (β-TCP) scaffolds alone or loaded with hAECs were implanted into the alveolar defects of rats. Micro-computed tomography evaluation and histologic studies were conducted. Our results validated the in vitro osteogenic capacity of hAECs by upregulation of Runx2, osterix, alkaline phosphatase, collagen I, and osteopontin, with positive biochemical staining for osteoblasts. An epithelial-mesenchymal transformation process might be involved in the osteogenic differentiation of hAECs by increased expression of transforming growth factor-β1. Our data also demonstrated that in vivo implantation of hAECs loaded on β-TCP scaffolds, not only improved bone regeneration by direct participation, but also reduced the early host immune response to the scaffolds. The presented data indicate that hAECs possess proper osteogenic differentiation potential and a modulatory influence on the early tissue remodeling process, making these cells a potential source of progenitor cells for clinical restoration of the alveolar defect. PMID:25368378

  1. Enhancement effect of poly(amino acid)s on insulin uptake in alveolar epithelial cells.

    PubMed

    Oda, Keisuke; Yumoto, Ryoko; Nagai, Junya; Katayama, Hirokazu; Takano, Mikihisa

    2012-01-01

    In this study, we elucidated the effect of poly(amino acid)s such as poly-L-ornithine (PLO) on FITC-insulin uptake in cultured alveolar type II epithelial cells, RLE-6TN. FITC-insulin uptake by RLE-6TN cells as well as its cell surface binding was markedly increased by PLO without cytotoxicity. The uptake of FITC-insulin in the presence of PLO was shown to be mediated by endocytosis, but in contrast to the uptake in the absence of PLO, the contribution of macropinocytosis emerged. Colocalization of FITC-insulin and LysoTracker Red was observed by confocal laser scanning microscopy both in the absence and presence of PLO, indicating that FITC-insulin was partly targeted to lysosomes in the cells and degraded. The half-life of the intracellular degradation of FITC-insulin was, however, prolonged by the presence of PLO. PLO also stimulated the uptake of other FITC-labeled compounds. Among them, the enhancement effects of PLO on FITC-albumin and FITC-insulin uptake were prominent. The effect of PLO on insulin absorption was also examined in in-vivo pulmonary administration in rats, and co-administration of PLO enhanced the hypoglycemic action of insulin. These findings suggest that co-administration of poly(amino acid)s such as PLO is a useful strategy for enhancing insulin uptake by alveolar epithelial cells and subsequent absorption from the lung. PMID:22510869

  2. Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide.

    PubMed

    Huang, Chunrong; Zheng, Haichong; He, Wanmei; Lu, Guifang; Li, Xia; Deng, Yubin; Zeng, Mian

    2016-05-20

    Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI. PMID:27103436

  3. Comparative effects of cocaine and cocaethylene on alveolar epithelial type II cells.

    PubMed

    Bazuaye-Ekwuyasi, Eseosa A; Ogunbileje, John O; Kaphalia, Bhupendra S; Eltorky, Mahmoud A; Okorodudu, Anthony O

    2015-01-01

    Abuse of cocaine (COC) and alcohol have been among the leading causes of non-prescription drug-related deaths in the USA and are known to cause acute and chronic lung diseases. The co-abuse of COC and alcohol results in the production of an active metabolite, cocaethylene (CE). The effects of COC and its metabolites on the respiratory system have been scarcely studied. This study was aimed at comparing the toxic effects of eqimolar concentration (1 mM) of COC and CE on alveolar epithelial type II cells. This was performed by measuring cell growth, viability, clonogenic activity, cell cycle and reactive oxygen species (ROS) generation. The treatment of CE and COC resulted in a significant inhibition of cell proliferation with the formation of an average of three colonies which measured about 1.74×10(-15) m each and 25 colonies each of about 5.73×10(-15) m, respectively, while untreated cells yielded 31 colonies of 8.75×10(-15) m (p<0.05). The treatments of CE and COC resulted in the reduction of the growth fraction of alveolar epithelial type II cells without significant decrease in viability. In addition, there was an approximately twofold increase in ROS generation as compared to the controls (p<0.05). Therefore, CE-induced inhibition of cellular proliferation may contribute to the pathogenesis of diffuse alveolar damage in co-abusers of COC and alcohol. PMID:26364649

  4. Efficient and rapid isolation and purification of mouse alveolar type II epithelial cells.

    PubMed

    Messier, Elise M; Mason, Robert J; Kosmider, Beata

    2012-09-01

    The alveolar surface is covered by an epithelium composed of 2 main cell types: type I and type II cells. Alveolar type II (ATII) cells have a distinct morphology with apical microvilli and characteristic lamellar bodies, which are the intracellular storage form of pulmonary surfactant. ATII cells play an important role in innate immunity and produce and secrete pulmonary surfactant. They proliferate to restore the epithelium after damage to the more sensitive type I cells. We developed an efficient and rapid method to isolate and purify ATII cells from mice. Alveolar epithelial cells were dissociated in the murine lung with dispase and lung tissue was gently minced with a GentleMACS Dissociator. ATII cell purification was performed using negative depletion with CD45 MicroBeads and positive selection for the epithelial-cell adhesion molecule (Ep-CAM) by magnetic labeling with Streptavidin MicroBeads in MACS LS columns. The purity of these cells as measured by flow cytometry was up to 92.1% and 91.1% for co-staining with Ep-CAM and cytokeratin and co-staining with Ep-CAM and SP-A, respectively. The resulting ATII cell population has a high purity, viability, and yield. The phenotype of isolated and cultured ATII cells was confirmed by electron micrographs, expression of surfactant proteins (SP-A, proSP-B, mature SP-B, proSP-C, SP-D), and lysophosphatidylcholine acyltransferase (LPCAT) by western blotting and immunocytofluorescence. This protocol is based on surface antigens and our data demonstrated that murine ATII cells can be rapidly isolated, efficiently purified, and effectively cultured. PMID:22888851

  5. Influenza Virus Infects Epithelial Stem/Progenitor Cells of the Distal Lung: Impact on Fgfr2b-Driven Epithelial Repair

    PubMed Central

    Quantius, Jennifer; Schmoldt, Carole; Vazquez-Armendariz, Ana I.; Becker, Christin; El Agha, Elie; Wilhelm, Jochen; Morty, Rory E.; Vadász, István; Mayer, Konstantin; Gattenloehner, Stefan; Fink, Ludger; Matrosovich, Mikhail; Li, Xiaokun; Seeger, Werner; Lohmeyer, Juergen; Bellusci, Saverio; Herold, Susanne

    2016-01-01

    Influenza Virus (IV) pneumonia is associated with severe damage of the lung epithelium and respiratory failure. Apart from efficient host defense, structural repair of the injured epithelium is crucial for survival of severe pneumonia. The molecular mechanisms underlying stem/progenitor cell mediated regenerative responses are not well characterized. In particular, the impact of IV infection on lung stem cells and their regenerative responses remains elusive. Our study demonstrates that a highly pathogenic IV infects various cell populations in the murine lung, but displays a strong tropism to an epithelial cell subset with high proliferative capacity, defined by the signature EpCamhighCD24lowintegrin(α6)high. This cell fraction expressed the stem cell antigen-1, highly enriched lung stem/progenitor cells previously characterized by the signature integrin(β4)+CD200+, and upregulated the p63/krt5 regeneration program after IV-induced injury. Using 3-dimensional organoid cultures derived from these epithelial stem/progenitor cells (EpiSPC), and in vivo infection models including transgenic mice, we reveal that their expansion, barrier renewal and outcome after IV-induced injury critically depended on Fgfr2b signaling. Importantly, IV infected EpiSPC exhibited severely impaired renewal capacity due to IV-induced blockade of β-catenin-dependent Fgfr2b signaling, evidenced by loss of alveolar tissue repair capacity after intrapulmonary EpiSPC transplantation in vivo. Intratracheal application of exogenous Fgf10, however, resulted in increased engagement of non-infected EpiSPC for tissue regeneration, demonstrated by improved proliferative potential, restoration of alveolar barrier function and increased survival following IV pneumonia. Together, these data suggest that tropism of IV to distal lung stem cell niches represents an important factor of pathogenicity and highlight impaired Fgfr2b signaling as underlying mechanism. Furthermore, increase of alveolar Fgf10

  6. Influenza Virus Infects Epithelial Stem/Progenitor Cells of the Distal Lung: Impact on Fgfr2b-Driven Epithelial Repair.

    PubMed

    Quantius, Jennifer; Schmoldt, Carole; Vazquez-Armendariz, Ana I; Becker, Christin; El Agha, Elie; Wilhelm, Jochen; Morty, Rory E; Vadász, István; Mayer, Konstantin; Gattenloehner, Stefan; Fink, Ludger; Matrosovich, Mikhail; Li, Xiaokun; Seeger, Werner; Lohmeyer, Juergen; Bellusci, Saverio; Herold, Susanne

    2016-06-01

    Influenza Virus (IV) pneumonia is associated with severe damage of the lung epithelium and respiratory failure. Apart from efficient host defense, structural repair of the injured epithelium is crucial for survival of severe pneumonia. The molecular mechanisms underlying stem/progenitor cell mediated regenerative responses are not well characterized. In particular, the impact of IV infection on lung stem cells and their regenerative responses remains elusive. Our study demonstrates that a highly pathogenic IV infects various cell populations in the murine lung, but displays a strong tropism to an epithelial cell subset with high proliferative capacity, defined by the signature EpCamhighCD24lowintegrin(α6)high. This cell fraction expressed the stem cell antigen-1, highly enriched lung stem/progenitor cells previously characterized by the signature integrin(β4)+CD200+, and upregulated the p63/krt5 regeneration program after IV-induced injury. Using 3-dimensional organoid cultures derived from these epithelial stem/progenitor cells (EpiSPC), and in vivo infection models including transgenic mice, we reveal that their expansion, barrier renewal and outcome after IV-induced injury critically depended on Fgfr2b signaling. Importantly, IV infected EpiSPC exhibited severely impaired renewal capacity due to IV-induced blockade of β-catenin-dependent Fgfr2b signaling, evidenced by loss of alveolar tissue repair capacity after intrapulmonary EpiSPC transplantation in vivo. Intratracheal application of exogenous Fgf10, however, resulted in increased engagement of non-infected EpiSPC for tissue regeneration, demonstrated by improved proliferative potential, restoration of alveolar barrier function and increased survival following IV pneumonia. Together, these data suggest that tropism of IV to distal lung stem cell niches represents an important factor of pathogenicity and highlight impaired Fgfr2b signaling as underlying mechanism. Furthermore, increase of alveolar Fgf10

  7. Mechanism underlying insulin uptake in alveolar epithelial cell line RLE-6TN.

    PubMed

    Oda, Keisuke; Yumoto, Ryoko; Nagai, Junya; Katayama, Hirokazu; Takano, Mikihisa

    2011-12-15

    For the development of efficient pulmonary delivery systems for protein and peptide drugs, it is important to understand their transport mechanisms in alveolar epithelial cells. In this study, the uptake mechanism for FITC-insulin in cultured alveolar epithelial cell line RLE-6TN was elucidated. FITC-insulin uptake by RLE-6TN cells was time-dependent, temperature-sensitive, and concentration-dependent. The uptake was inhibited by metabolic inhibitors, cytochalasin D, clathrin-mediated endocytosis inhibitors, and dynasore, an inhibitor of dynamin GTPase. On the other hand, no inhibitory effect was observed with caveolae-mediated endocytosis inhibitors and a macropinocytosis inhibitor. Intracellular FITC-insulin was found to be partly transported to the basal side of the epithelial cell monolayers. In addition, colocalization of FITC-insulin and LysoTracker Red was observed on confocal laser scanning microscopy, indicating that FITC-insulin was partly targeted to lysosomes. In accordance with these findings, SDS-PAGE/fluoroimage analysis showed that intact FITC-insulin in the cells was eliminated with time. The possible receptor involved in FITC-insulin uptake by RLE-6TN cells was examined by using siRNA. Transfection of the cells with megalin or insulin receptor siRNA successfully reduced the corresponding mRNA expression. FITC-insulin uptake decreased on the transfection with insulin receptor siRNA, but not that with megalin siRNA. These results suggest that insulin is taken up through endocytosis in RLE-6TN cells, and after the endocytosis, the intracellular insulin is partly degraded in lysosomes and partly transported to the basal side. Insulin receptor, but not megalin, may be involved at least partly in insulin endocytosis in RLE-6TN cells. PMID:22004610

  8. Mesenchymal stem cells protect from hypoxia-induced alveolar epithelial-mesenchymal transition.

    PubMed

    Uzunhan, Yurdagül; Bernard, Olivier; Marchant, Dominique; Dard, Nicolas; Vanneaux, Valérie; Larghero, Jérôme; Gille, Thomas; Clerici, Christine; Valeyre, Dominique; Nunes, Hilario; Boncoeur, Emilie; Planès, Carole

    2016-03-01

    Administration of bone marrow-derived human mesenchymal stem cells (hMSC) reduces lung inflammation, fibrosis, and mortality in animal models of lung injury, by a mechanism not completely understood. We investigated whether hMSC would prevent epithelial-mesenchymal transition (EMT) induced by hypoxia in primary rat alveolar epithelial cell (AEC). In AEC cultured on semipermeable filters, prolonged hypoxic exposure (1.5% O2 for up to 12 days) induced phenotypic changes consistent with EMT, i.e., a change in cell morphology, a decrease in transepithelial resistance (Rte) and in the expression of epithelial markers [zonula occludens-1 (ZO-1), E-cadherin, AQP-5, TTF-1], together with an increase in mesenchymal markers [vimentin, α-smooth muscle actin (α-SMA)]. Expression of transcription factors driving EMT such as SNAIL1, ZEB1, and TWIST1 increased after 2, 24, and 48 h of hypoxia, respectively. Hypoxia also induced TGF-β1 mRNA expression and the secretion of active TGF-β1 in apical medium, and the expression of connective tissue growth factor (CTGF), two inducers of EMT. Coculture of AEC with hMSC partially prevented the decrease in Rte and in ZO-1, E-cadherin, and TTF-1 expression, and the increase in vimentin expression induced by hypoxia. It also abolished the increase in TGF-β1 expression and in TGF-β1-induced genes ZEB1, TWIST1, and CTGF. Finally, incubation with human recombinant KGF at a concentration similar to what was measured in hMSC-conditioned media restored the expression of TTF-1 and prevented the increase in TWIST1, TGF-β1, and CTGF in hypoxic AEC. Our results indicate that hMSC prevent hypoxia-induced alveolar EMT through the paracrine modulation of EMT signaling pathways and suggest that this effect is partly mediated by KGF. PMID:26702148

  9. Lipopolysaccharide-induced epithelial monoamine oxidase mediates alveolar bone loss in a rat chronic wound model.

    PubMed

    Ekuni, Daisuke; Firth, James D; Nayer, Tarun; Tomofuji, Takaaki; Sanbe, Toshihiro; Irie, Koichiro; Yamamoto, Tatsuo; Oka, Takashi; Liu, Zhenzi; Vielkind, Juergen; Putnins, Edward E

    2009-10-01

    Reactive oxygen species (ROS) production is an antimicrobial response to pathogenic challenge that may, in the case of persistent infection, have deleterious effects on the tissue of origin. A rat periodontal disease model was used to study ROS-induced chronic epithelial inflammation and bone loss. Lipopolysaccharide (LPS) was applied for 8 weeks into the gingival sulcus, and histological analysis confirmed the onset of chronic disease. Junctional epithelium was collected from healthy and diseased animals using laser-capture microdissection, and expression microarray analysis was performed. Of 19,730 genes changed in disease, 42 were up-regulated >/=4-fold. Three of the top 10 LPS-induced genes, monoamine oxidase B (MAO/B) and flavin-containing monooxygenase 1 and 2, are implicated in ROS signaling. LPS-associated induction of the ROS mediator H(2)O(2), as well as MAO/B and tumor necrosis factor (TNF)-alpha levels were validated in the rat histological sections and a porcine junctional epithelial cell culture model. Topical MAO inhibitors significantly counteracted LPS-associated elevation of H(2)O(2) production and TNF-alpha expression in vivo and in vitro, inhibited disease-associated apical migration and proliferation of junctional epithelium and inhibited induced systemic H(2)O(2) levels and alveolar bone loss in vivo. These results suggest that LPS induces chronic wounds via elevated MAO/B-mediated increases in H(2)O(2) and TNF-alpha activity by epithelial cells and is further associated with more distant effects on systemic oxidative stress and alveolar bone loss. PMID:19779138

  10. Evidence-based outcomes following inferior alveolar and lingual nerve injury and repair: a systematic review.

    PubMed

    Kushnerev, E; Yates, J M

    2015-10-01

    The inferior alveolar nerve (IAN) and lingual (LN) are susceptible to iatrogenic surgical damage. Systematically review recent clinical evidence regarding IAN/LN repair methods and to develop updated guidelines for managing injury. Recent publications on IAN/LN microsurgical repair from Medline, Embase and Cochrane Library databases were screened by title/abstract. Main texts were appraised for exclusion criteria: no treatment performed or results provided, poor/lacking procedural description, cohort <3 patients. Of 366 retrieved papers, 27 were suitable for final analysis. Treatment type for injured IANs/LNs depended on injury type, injury timing, neurosensory disturbances and intra-operative findings. Best functional nerve recovery occurred after direct apposition and suturing if nerve ending gaps were <10 mm; larger gaps required nerve grafting (sural/greater auricular nerve). Timing of microneurosurgical repair after injury remains debated. Most authors recommend surgery when neurosensory deficit shows no improvement 90 days post-diagnosis. Nerve transection diagnosed intra-operatively should be repaired in situ; minor nerve injury repair can be delayed. No consensus exists regarding optimal methods and timing for IAN/LN repair. We suggest a schematic guideline for treating IAN/LN injury, based on the most current evidence. We acknowledge that additional RCTs are required to provide definitive confirmation of optimal treatment approaches. PMID:26059454

  11. Effect of mycobacterial secretory proteins on the cellular integrity and cytokine profile of type II alveolar epithelial cells

    PubMed Central

    Adlakha, Nidhi; Vir, Pooja; Verma, Indu

    2012-01-01

    Background: Pulmonary tuberculosis (TB) is caused by Mycobacterium tuberculosis (M. tb). In lungs, alveolar macrophages and type II alveolar epithelial cells serve as a replicative niche for this pathogen. Secretory proteins released by actively replicating tubercle bacilli are known to interact with host cells at the initial stages of infection. To understand the role of these cells in TB pathogenesis, it is important to identify the mycobacterial components involved in interaction with alveolar epithelial cells. Materials and Methods: We fractionated the whole secretory proteome of M. tb H37Rv into 10 narrow molecular mass fractions (A1-A10; <20 kDa to >90 kDa) that were studied for their binding potential with A549; type II alveolar epithelial cell line. We also studied the consequences of this interaction in terms of change in epithelial cell viability by MTT assay and cytokine release by ELISA. Results: Our results show that several mycobacterial proteins bind and confer cytolysis in epithelial cells. Amongst all the fractions, proteins ranging from 35-45 kDa (A5) exhibited highest binding to A549 cells with a consequence of cytolysis of these cells. This fraction (A5) also led to release of various cytokines important in anti-mycobacterial immunity. Conclusion: Fraction A5 (35-45 kDa) of mycobacterial secretory proteome play an important role in mediating M. tb interaction with type II alveolar epithelial cells with the consequences detrimental for the TB pathogenesis. Further studies are being carried out to identify the candidate proteins from this region. PMID:23243342

  12. Environmental Particulate (PM2.5) Augments Stiffness-Induced Alveolar Epithelial Cell Mechanoactivation of Transforming Growth Factor Beta

    PubMed Central

    Dysart, Marilyn M.; Galvis, Boris R.; Russell, Armistead G.; Barker, Thomas H.

    2014-01-01

    Dysfunctional pulmonary homeostasis and repair, including diseases such as pulmonary fibrosis (PF), chronic obstructive pulmonary disease (COPD), and tumorigenesis have been increasing over the past decade, a fact that heavily implicates environmental influences. Several investigations have suggested that in response to increased transforming growth factor - beta (TGFβ) signaling, the alveolar type II (ATII) epithelial cell undergoes phenotypic changes that may contribute to the complex pathobiology of PF. We have previously demonstrated that increased tissue stiffness associated with PF is a potent extracellular matrix (ECM) signal for epithelial cell activation of TGFβ. The work reported here explores the relationship between tissue stiffness and exposure to environmental stimuli in the activation of TGFβ. We hypothesized that exposure of ATII cells to fine particulate matter (PM2.5) will result in enhanced cell contractility, TGFβ activation, and subsequent changes to ATII cell phenotype. ATII cells were cultured on increasingly stiff substrates with or without addition of PM2.5. Exposure to PM2.5 resulted in increased activation of TGFβ, increased cell contractility, and elongation of ATII cells. Most notably, on 8 kPa substrates, a stiffness greater than normal but less than established fibrotic lung, addition of PM2.5 resulted in increased cortical cell stiffness, enhanced actin staining and cell elongation; a result not seen in the absence of PM2.5. Our work suggests that PM2.5 exposure additionally enhances the existing interaction between ECM stiffness and TGFβ that has been previously reported. Furthermore, we show that this additional enhancement is likely a consequence of intracellular reactive oxygen species (ROS) leading to increased TGFβ signaling events. These results highlight the importance of both the micromechanical and biochemical environment in lung disease initiation and suggest that individuals in early stages of lung remodeling

  13. Hypoxia-induced alveolar epithelial-mesenchymal transition requires mitochondrial ROS and hypoxia-inducible factor 1

    PubMed Central

    Zhou, Guofei; Dada, Laura A.; Wu, Minghua; Kelly, Aileen; Trejo, Humberto; Zhou, Qiyuan; Varga, John

    2009-01-01

    Patients with acute lung injury develop hypoxia, which may lead to lung dysfunction and aberrant tissue repair. Recent studies have suggested that epithelial-mesenchymal transition (EMT) contributes to pulmonary fibrosis. We sought to determine whether hypoxia induces EMT in alveolar epithelial cells (AEC). We found that hypoxia induced the expression of α-smooth muscle actin (α-SMA) and vimentin and decreased the expression of E-cadherin in transformed and primary human, rat, and mouse AEC, suggesting that hypoxia induces EMT in AEC. Both severe hypoxia and moderate hypoxia induced EMT. The reactive oxygen species (ROS) scavenger Euk-134 prevented hypoxia-induced EMT. Moreover, hypoxia-induced expression of α-SMA and vimentin was prevented in mitochondria-deficient ρ0 cells, which are incapable of ROS production during hypoxia. CoCl2 and dimethyloxaloylglycine, two compounds that stabilize hypoxia-inducible factor (HIF)-α under normoxia, failed to induce α-SMA expression in AEC. Furthermore, overexpression of constitutively active HIF-1α did not induce α-SMA. However, loss of HIF-1α or HIF-2α abolished induction of α-SMA mRNA during hypoxia. Hypoxia increased the levels of transforming growth factor (TGF)-β1, and preincubation of AEC with SB431542, an inhibitor of the TGF-β1 type I receptor kinase, prevented the hypoxia-induced EMT, suggesting that the process was TGF-β1 dependent. Furthermore, both ROS and HIF-α were necessary for hypoxia-induced TGF-β1 upregulation. Accordingly, we have provided evidence that hypoxia induces EMT of AEC through mitochondrial ROS, HIF, and endogenous TGF-β1 signaling. PMID:19801454

  14. Stanniocalcin-1 is induced by hypoxia inducible factor in rat alveolar epithelial cells.

    PubMed

    Ito, Yoko; Zemans, Rachel; Correll, Kelly; Yang, Ivana V; Ahmad, Aftab; Gao, Bifeng; Mason, Robert J

    2014-10-01

    Alveolar type II (ATII) cells remain differentiated and express surfactant proteins when cultured at an air-liquid (A/L) interface. When cultured under submerged conditions, ATII cells dedifferentiate and change their gene expression profile. We have previously shown that gene expression under submerged conditions is regulated by hypoxia inducible factor (HIF) signaling due to focal hypoxia resulting from ATII cell metabolism. Herein, we sought to further define gene expression changes in ATII cells cultured under submerged conditions. We performed a genome wide microarray on RNA extracted from rat ATII cells cultured under submerged conditions for 24-48h after switching from an A/L interface. We found significant alterations in gene expression, including upregulation of the HIF target genes stanniocalcin-1 (STC1), tyrosine hydroxylase (Th), enolase (Eno) 2, and matrix metalloproteinase (MMP) 13, and we verified upregulation of these genes by RT-PCR. Because STC1, a highly evolutionarily conserved glycoprotein with anti-inflammatory, anti-apoptotic, anti-oxidant, and wound healing properties, is widely expressed in the lung, we further explored the potential functions of STC1 in the alveolar epithelium. We found that STC1 was induced by hypoxia and HIF in rat ATII cells, and this induction occurred rapidly and reversibly. We also showed that recombinant human STC1 (rhSTC1) enhanced cell motility with extended lamellipodia formation in alveolar epithelial cell (AEC) monolayers but did not inhibit the oxidative damage induced by LPS. We also confirmed that STC1 was upregulated by hypoxia and HIF in human lung epithelial cells. In this study, we have found that several HIF target genes including STC1 are upregulated in AECs by a submerged condition, that STC1 is regulated by hypoxia and HIF, that this regulation is rapidly and reversibly, and that STC1 enhances wound healing moderately in AEC monolayers. However, STC1 did not inhibit oxidative damage in rat AECs

  15. [Inhibitory effect of Panax notoginseng saponins on alveolar epithelial to mesenchymal transition].

    PubMed

    Ren, Zhou-xin; Yu, Hai-bin; Li, Jian-sheng; Shen, Jun-ling; Li, Jun-kai; Luo, Shan

    2015-12-01

    In the study, the effects of Panax notoginseng saponins (PNS) on alveolar epithelial to mesenchymal transition (EMT) and extracellular matrix degradation were observed in a type of human alveolar epithelial cell, A549 cells, stimulated by TGF-beta1. Firstly, MTT method was applied to evaluation of cellular proliferation and found that PNS from 12.5 mg x L(-1) to 200 mg x L(-1) dosage could not inhibit significantly cellular proliferation. Then, cells were divided into five groups, normal group, TGF-beta1 group, TGF-beta1 + 50 mg x L(-1) PNS group, TGF-beta1 + 100 mg x L(-1) PNS group and TGF-beta1 + 200 mg x L(-1) PNS group. Normal cells were not stimulatec by TGF-beta1; TGF-beta1 cells were only stimulated by TGF-beta1 and the other cells were stimulated by TGF-beta1 with different doses of PNS, respectively. After stimulation, cells and supernatants were collected for assays. Cellular roundness was applied to quantitative evaluation of morphological change. Immunocytochemistry was applied to examine E-cadherion, a-SMA and FN proteins expression in the cells. Enzyme linked-immunosorbent assay was applied to MMP-9 and TIMP-1 levels. The results showed that EMT of A549 cells was induced by TGF-beta1, showing significant change of roundness, E-cadherion, alpha-SMA and FN (P < 0.05, P < 0.01). Compared to TGF-beta1, PNS significantly inhibited the changes of roundness (P < 0.05), FN and alpha-SMA (P < 0.05, P < 0.01) and not significantly inhibited the change of E-cadherion. Furthermore, MMP-9 levels were significantly increased by TGFbeta1 stimulation (P < 0.05), without significant change of TIMP-1. Compared with TGF-beta1, PNS could significantly increase MMP-9 level (P < 0.05) and decrease TIMP-1 levels (P < 0.05, P < 0.01). In conclusion, PNS could inhibit alveolar epithelial cell EMT induced by TGF-beta1, with increase of extracellular matrix degradation ability, which showed anti-fibrosis of lung ability. PMID:27141681

  16. Influenza induces IL-8 and GM-CSF secretion by human alveolar epithelial cells through HGF/c-Met and TGF-α/EGFR signaling

    PubMed Central

    Correll, Kelly; Zemans, Rachel L.; Leslie, Christina C.; Murphy, Robert C.; Mason, Robert J.

    2015-01-01

    The most severe complication of influenza is viral pneumonia, which can lead to the acute respiratory distress syndrome. Alveolar epithelial cells (AECs) are the first cells that influenza virus encounters upon entering the alveolus. Infected epithelial cells produce cytokines that attract and activate neutrophils and macrophages, which in turn induce damage to the epithelial-endothelial barrier. Hepatocyte growth factor (HGF)/c-Met and transforming growth factor-α (TGF-α)/epidermal growth factor receptor (EGFR) are well known to regulate repair of damaged alveolar epithelium by stimulating cell migration and proliferation. Recently, TGF-α/EGFR signaling has also been shown to regulate innate immune responses in bronchial epithelial cells. However, little is known about whether HGF/c-Met signaling alters the innate immune responses and whether the innate immune responses in AECs are regulated by HGF/c-Met and TGF-α/EGFR. We hypothesized that HGF/c-Met and TGF-α/EGFR would regulate innate immune responses to influenza A virus infection in human AECs. We found that recombinant human HGF (rhHGF) and rhTGF-α stimulated primary human AECs to secrete IL-8 and granulocyte macrophage colony-stimulating factor (GM-CSF) strongly and IL-6 and monocyte chemotactic protein 1 moderately. Influenza infection stimulated the secretion of IL-8 and GM-CSF by AECs plated on rat-tail collagen through EGFR activation likely by TGF-α released from AECs and through c-Met activated by HGF secreted from lung fibroblasts. HGF secretion by fibroblasts was stimulated by AEC production of prostaglandin E2 during influenza infection. We conclude that HGF/c-Met and TGF-α/EGFR signaling enhances the innate immune responses by human AECs during influenza infections. PMID:26033355

  17. Influenza induces IL-8 and GM-CSF secretion by human alveolar epithelial cells through HGF/c-Met and TGF-α/EGFR signaling.

    PubMed

    Ito, Yoko; Correll, Kelly; Zemans, Rachel L; Leslie, Christina C; Murphy, Robert C; Mason, Robert J

    2015-06-01

    The most severe complication of influenza is viral pneumonia, which can lead to the acute respiratory distress syndrome. Alveolar epithelial cells (AECs) are the first cells that influenza virus encounters upon entering the alveolus. Infected epithelial cells produce cytokines that attract and activate neutrophils and macrophages, which in turn induce damage to the epithelial-endothelial barrier. Hepatocyte growth factor (HGF)/c-Met and transforming growth factor-α (TGF-α)/epidermal growth factor receptor (EGFR) are well known to regulate repair of damaged alveolar epithelium by stimulating cell migration and proliferation. Recently, TGF-α/EGFR signaling has also been shown to regulate innate immune responses in bronchial epithelial cells. However, little is known about whether HGF/c-Met signaling alters the innate immune responses and whether the innate immune responses in AECs are regulated by HGF/c-Met and TGF-α/EGFR. We hypothesized that HGF/c-Met and TGF-α/EGFR would regulate innate immune responses to influenza A virus infection in human AECs. We found that recombinant human HGF (rhHGF) and rhTGF-α stimulated primary human AECs to secrete IL-8 and granulocyte macrophage colony-stimulating factor (GM-CSF) strongly and IL-6 and monocyte chemotactic protein 1 moderately. Influenza infection stimulated the secretion of IL-8 and GM-CSF by AECs plated on rat-tail collagen through EGFR activation likely by TGF-α released from AECs and through c-Met activated by HGF secreted from lung fibroblasts. HGF secretion by fibroblasts was stimulated by AEC production of prostaglandin E2 during influenza infection. We conclude that HGF/c-Met and TGF-α/EGFR signaling enhances the innate immune responses by human AECs during influenza infections. PMID:26033355

  18. Bim mediates mitochondria-regulated particulate matter-induced apoptosis in alveolar epithelial cells

    PubMed Central

    Zhang, J.; Ghio, A.J.; Chang, W.; Kamdar, O.; Rosen, G.D.; Upadhyay, D.

    2007-01-01

    We studied the role of Bim, a pro-apoptotic BCL-2 family member in Airborne particulate matter (PM 2.5 μm)-induced apoptosis in alveolar epithelial cells (AEC). PM induced AEC apoptosis by causing significant reduction of mitochondrial membrane potential and increase in caspase-9, caspase-3 and PARP-1 activation. PM upregulated pro-apoptotic protein Bim and enhanced translocation of Bim to the mitochondria. ShRNABim blocked PM-induced apoptosis by preventing activation of the mitochondrial death pathway suggesting a role of Bim in the regulation of mitochondrial pathway in AEC. Accordingly, we provide the evidence that Bim mediates PM-induced apoptosis via mitochondrial pathway. PMID:17716672

  19. Apocynin increases glutathione synthesis and activates AP-1 in alveolar epithelial cells.

    PubMed

    Lapperre, T S; Jimenez, L A; Antonicelli, F; Drost, E M; Hiemstra, P S; Stolk, J; MacNee, W; Rahman, I

    1999-01-25

    Apocynin (4-hydroxy-3-methoxy-acetophenone) is a potent intracellular inhibitor of superoxide anion production in neutrophils. In this study, we studied the effect of apocynin on the regulation of the antioxidant glutathione (GSH) and activation of the transcription factor AP-I in human alveolar epithelial cells (A549). Apocynin enhanced intracellular GSH by increasing gamma-glutamylcysteine synthetase activity in A549 cells. Apocynin also increased the expression of gamma-GCS heavy subunit mRNA. This was associated with increased AP-1 DNA binding as measured by the electrophoretic mobility shift assay. These data indicate that apocynin displays antioxidant properties, in part, by increasing glutathione synthesis through activation of AP-1. PMID:9989612

  20. Combinations of differentiation markers distinguish subpopulations of alveolar epithelial cells in adult lung.

    PubMed

    Liebler, Janice M; Marconett, Crystal N; Juul, Nicholas; Wang, Hongjun; Liu, Yixin; Flodby, Per; Laird-Offringa, Ite A; Minoo, Parviz; Zhou, Beiyun

    2016-01-15

    Distal lung epithelium is maintained by proliferation of alveolar type II (AT2) cells and, for some daughter AT2 cells, transdifferentiation into alveolar type I (AT1) cells. We investigated if subpopulations of alveolar epithelial cells (AEC) exist that represent various stages in transdifferentiation from AT2 to AT1 cell phenotypes in normal adult lung and if they can be identified using combinations of cell-specific markers. Immunofluorescence microscopy showed that, in distal rat and mouse lungs, ∼ 20-30% of NKX2.1(+) (or thyroid transcription factor 1(+)) cells did not colocalize with pro-surfactant protein C (pro-SP-C), a highly specific AT2 cell marker. In distal rat lung, NKX2.1(+) cells coexpressed either pro-SP-C or the AT1 cell marker homeodomain only protein x (HOPX). Not all HOPX(+) cells colocalize with the AT1 cell marker aquaporin 5 (AQP5), and some AQP5(+) cells were NKX2.1(+). HOPX was expressed earlier than AQP5 during transdifferentiation in rat AEC primary culture, with robust expression of both by day 7. We speculate that NKX2.1 and pro-SP-C colocalize in AT2 cells, NKX2.1 and HOPX or AQP5 colocalize in intermediate or transitional cells, and HOPX and AQP5 are expressed without NKX2.1 in AT1 cells. These findings suggest marked heterogeneity among cells previously identified as exclusively AT1 or AT2 cells, implying the presence of subpopulations of intermediate or transitional AEC in normal adult lung. PMID:26545903

  1. Lung epithelial GM-CSF improves host defense function and epithelial repair in influenza virus pneumonia-a new therapeutic strategy?

    PubMed

    Rösler, Barbara; Herold, Susanne

    2016-12-01

    Influenza viruses (IVs) circulate seasonally and are a common cause of respiratory infections in pediatric and adult patients. Additionally, recurrent pandemics cause massive morbidity and mortality worldwide. Infection may result in rapid progressive viral pneumonia with fatal outcome. Since accurate treatment strategies are still missing, research refocuses attention to lung pathology and cellular crosstalk to develop new therapeutic options.Alveolar epithelial cells (AECs) play an important role in orchestrating the pulmonary antiviral host response. After IV infection they release a cascade of immune mediators, one of which is granulocyte and macrophage colony-stimulating factor (GM-CSF). GM-CSF is known to promote differentiation, activation and mobilization of myeloid cells. In the lung, GM-CSF drives immune functions of alveolar macrophages and dendritic cells (DCs) and also improves epithelial repair processes through direct interaction with AECs. During IV infection, AEC-derived GM-CSF shows a lung-protective effect that is also present after local GM-CSF application. This mini-review provides an overview on GM-CSF-modulated immune responses to IV pneumonia and its therapeutic potential in severe IV pneumonia. PMID:27480877

  2. Isolation and characterization of alveolar epithelial type II cells derived from mouse embryonic stem cells.

    PubMed

    Sun, Huanhuan; Quan, Yuan; Yan, Qing; Peng, Xinmiao; Mao, Zhengmei; Wetsel, Rick A; Wang, Dachun

    2014-06-01

    The use of embryonic stem cells (ESCs) to regenerate distal lung epithelia damaged by injuries or diseases requires development of safe and efficient methodologies that direct ESC differentiation into transplantable distal lung epithelial progenitors. Time-consuming culture procedure and low differentiation efficiency are major problems that are associated with conventional differentiation approaches via embryoid body formation. The use of a growth factor cocktail or a lung-specific cell-conditioned medium to enrich definitive endoderm for efficient differentiation of mouse ESCs (mESC) into alveolar epithelial progenitor type II cells (ATIICs) has been reported, but not yet successful for generating a homogenous population of ATIICs for tissue regeneration purpose, and it remains unclear whether or not those mESC-derived ATIICs possess normal biological functions. Here, we report a novel method using a genetically modified mESC line harboring an ATIIC-specific neomycin(R) transgene in Rosa 26 locus. We showed that ATIICs can be efficiently differentiated from mESCs as early as day 7 by culturing them directly on Matrigel-coated plates in DMEM containing 15% knockout serum replacement. With this culture condition, the genetically modified mESCs can be selectively differentiated into a homogenous population (>99%) of ATIICs. Importantly, the mESC-derived ATIICs (mESC-ATIICs) exhibited typical lamellar bodies and expressed surfactant protein A, B, and C as normal control ATIICs. When cultured with an air-liquid-interface culture system in Small Airway Epithelial Cell Growth Medium, the mESC-ATIICs can be induced to secrete surfactant proteins after being treated with dibutyryl cAMP+dexamethasone. These mESC-ATIICs can synthesize and secrete surfactant lipid in response to secretagogue, demonstrating active surfactant metabolism in mESC-ATIICs as that seen in normal control ATIICs. In addition, we demonstrated that the selected mESC-ATIICs can be maintained on Matrigel

  3. Role of primary human alveolar epithelial cells in host defense against Francisella tularensis infection.

    PubMed

    Gentry, Megan; Taormina, Joanna; Pyles, Richard B; Yeager, Linsey; Kirtley, Michelle; Popov, Vsevolod L; Klimpel, Gary; Eaves-Pyles, Tonyia

    2007-08-01

    Francisella tularensis, an intracellular pathogen, is highly virulent when inhaled. Alveolar epithelial type I (ATI) and type II (ATII) cells line the majority of the alveolar surface and respond to inhaled pathogenic bacteria via cytokine secretion. We hypothesized that these cells contribute to the lung innate immune response to F. tularensis. Results demonstrated that the live vaccine strain (LVS) contacted ATI and ATII cells by 2 h following intranasal inoculation of mice. In culture, primary human ATI or ATII cells, grown on transwell filters, were stimulated on the apical (AP) surface with virulent F. tularensis Schu 4 or LVS. Basolateral (BL) conditioned medium (CM), collected 6 and 24 h later, was added to the BL surfaces of transwell cultures of primary human pulmonary microvasculature endothelial cells (HPMEC) prior to the addition of polymorphonuclear leukocytes (PMNs) or dendritic cells (DCs) to the AP surface. HPMEC responded to S4- or LVS-stimulated ATII, but not ATI, CM as evidenced by PMN and DC migration. Analysis of the AP and BL ATII CM revealed that both F. tularensis strains induced various levels of a variety of cytokines via NF-kappaB activation. ATII cells pretreated with an NF-kappaB inhibitor prior to F. tularensis stimulation substantially decreased interleukin-8 secretion, which did not occur through Toll-like receptor 2, 2/6, 4, or 5 stimulation. These data indicate a crucial role for ATII cells in the innate immune response to F. tularensis. PMID:17502386

  4. Role of Primary Human Alveolar Epithelial Cells in Host Defense against Francisella tularensis Infection▿

    PubMed Central

    Gentry, Megan; Taormina, Joanna; Pyles, Richard B.; Yeager, Linsey; Kirtley, Michelle; Popov, Vsevolod L.; Klimpel, Gary; Eaves-Pyles, Tonyia

    2007-01-01

    Francisella tularensis, an intracellular pathogen, is highly virulent when inhaled. Alveolar epithelial type I (ATI) and type II (ATII) cells line the majority of the alveolar surface and respond to inhaled pathogenic bacteria via cytokine secretion. We hypothesized that these cells contribute to the lung innate immune response to F. tularensis. Results demonstrated that the live vaccine strain (LVS) contacted ATI and ATII cells by 2 h following intranasal inoculation of mice. In culture, primary human ATI or ATII cells, grown on transwell filters, were stimulated on the apical (AP) surface with virulent F. tularensis Schu 4 or LVS. Basolateral (BL) conditioned medium (CM), collected 6 and 24 h later, was added to the BL surfaces of transwell cultures of primary human pulmonary microvasculature endothelial cells (HPMEC) prior to the addition of polymorphonuclear leukocytes (PMNs) or dendritic cells (DCs) to the AP surface. HPMEC responded to S4- or LVS-stimulated ATII, but not ATI, CM as evidenced by PMN and DC migration. Analysis of the AP and BL ATII CM revealed that both F. tularensis strains induced various levels of a variety of cytokines via NF-κB activation. ATII cells pretreated with an NF-κB inhibitor prior to F. tularensis stimulation substantially decreased interleukin-8 secretion, which did not occur through Toll-like receptor 2, 2/6, 4, or 5 stimulation. These data indicate a crucial role for ATII cells in the innate immune response to F. tularensis. PMID:17502386

  5. Sustained distribution of aerosolized PEGylated liposomes in epithelial lining fluids on alveolar surfaces.

    PubMed

    Kaneko, Keita; Togami, Kohei; Yamamoto, Eri; Wang, Shujun; Morimoto, Kazuhiro; Itagaki, Shirou; Chono, Sumio

    2016-10-01

    The distribution characteristics of aerosolized PEGylated liposomes in alveolar epithelial lining fluid (ELF) were examined in rats, and the ensuing mechanisms were investigated in the in vitro uptake and protein adsorption experiments. Nonmodified or PEGylated liposomes (particle size 100 nm) were aerosolized into rat lungs. PEGylated liposomes were distributed more sustainably in ELFs than nonmodified liposomes. Furthermore, the uptake of PEGylated liposomes by alveolar macrophages (AMs) was less than that of nonmodified liposomes. In further in vitro uptake experiments, nonmodified and PEGylated liposomes were opsonized with rat ELF components and then added to NR8383 cells as cultured rat AMs. The uptake of opsonized PEGylated liposomes by NR8383 cells was lower than that of opsonized nonmodified liposomes. Moreover, the protein absorption levels in opsonized PEGylated liposomes were lower than those in opsonized nonmodified liposomes. These findings suggest that sustained distributions of aerosolized PEGylated liposomes in ELFs reflect evasion of liposomal opsonization with surfactant proteins and consequent reductions in uptake by AMs. These data indicate the potential of PEGylated liposomes as aerosol-based drug delivery system that target ELF for the treatment of respiratory diseases. PMID:27334278

  6. Alveolar macrophages modulate the epithelial cell response to coal dust in vitro.

    PubMed

    Lee, Y C; Rannels, D E

    1996-01-01

    The response of the alveolar epithelium to coal dust exposure is poorly understood. Coal or other dusts may act on the epithelium directly or indirectly through nearby alveolar macrophages (AM) that produce cytokines and other soluble products. AM and type II pneumocytes (T2P) were thus exposed to dust in coculture to evaluate their possible interactions. Anthracite coal dust PSOC 867 increased synthesis of extracellular matrix (ECM) components by T2P. AM alone did not produce ECM. Similarly, coculture of T2P with AM (3.75:1) had little effect on epithelial ECM synthesis. In contrast, coculture of T2P with AM significantly increased PSOC 867 effects on T2P rates of ECM synthesis, ECM fibronectin content, and T2P levels of fibronectin mRNA. AM-conditioned medium did not change the PSOC 867 effect on T2P. Neither control nor PSOC 867-treated AM on Falcon culture inserts (0.45-micron pore size) over T2P stimulated ECM synthesis by either untreated or dust-exposed epithelium. Thus AM-mediated changes in ECM synthesis by PSOC 867-treated T2P require close cell-cell interactions, suggesting a role for cell-cell contact or for short-lived soluble mediators of the AM effects. PMID:8772535

  7. Shape matters: effects of silver nanospheres and wires on human alveolar epithelial cells

    PubMed Central

    2011-01-01

    Background In nanotoxicology, the exact role of particle shape, in relation to the composition, on the capacity to induce toxicity is largely unknown. We investigated the toxic and immunotoxic effects of silver wires (length: 1.5 - 25 μm; diameter 100 - 160 nm), spherical silver nanoparticles (30 nm) and silver microparticles (<45 μm) on alveolar epithelial cells (A549). Methods Wires and nanoparticles were synthesized by wet-chemistry methods and extensively characterized. Cell viability and cytotoxicity were assessed and potential immunotoxic effects were investigated. To compare the effects on an activated and a resting immune system, cells were stimulated with rhTNF-α or left untreated. Changes in intracellular free calcium levels were determined using calcium imaging. Finally, ion release from the particles was assessed by ICP-MS and the effects of released ions on cell viability and cytotoxicity were tested. Results No effects were observed for the spherical particles, whereas the silver wires significantly reduced cell viability and increased LDH release from A549 cells. Cytokine promoter induction and NF-κB activation decreased in a concentration dependent manner similar to the decrease seen in cell viability. In addition, a strong increase of intracellular calcium levels within minutes after addition of wires was observed. This toxicity was not due to free silver ions, since the samples with the highest ion release did not induce toxicity and ion release control experiments with cells treated with pre-incubated medium did not show any effects either. Conclusions These data showed that silver wires strongly affect the alveolar epithelial cells, whereas spherical silver particles had no effect. This supports the hypothesis that shape is one of the important factors that determine particle toxicity. PMID:22208550

  8. Hyperoxia increases the elastic modulus of alveolar epithelial cells through Rho kinase.

    PubMed

    Wilhelm, Kristina R; Roan, Esra; Ghosh, Manik C; Parthasarathi, Kaushik; Waters, Christopher M

    2014-02-01

    Patients with acute lung injury are administered high concentrations of oxygen during mechanical ventilation, and while both hyperoxia and mechanical ventilation are necessary, each can independently cause additional injury. However, the precise mechanisms that lead to injury are not well understood. We hypothesized that alveolar epithelial cells may be more susceptible to injury caused by mechanical ventilation because hyperoxia causes cells to be stiffer due to increased filamentous actin (f-actin) formation via the GTPase RhoA and its effecter Rho kinase (ROCK). We examined cytoskeletal structures in cultured murine lung alveolar epithelial cells (MLE-12) under normoxic and hyperoxic (48 h) conditions. We also measured cell elasticity (E) using an atomic force microscope in the indenter mode. Hyperoxia caused increased f-actin stress fibers and bundle formation, an increase in g- and f-actin, an increase in nuclear area and a decrease in nuclear height, and cells became stiffer (higher E). Treatment with an inhibitor (Y-27632) of ROCK significantly decreased E and prevented the cytoskeletal changes, while it did not influence the nuclear height and area. Pre-exposure of cells to hyperoxia promoted detachment when cells were subsequently stretched cyclically, but the ROCK inhibitor prevented this effect. Hyperoxia caused thickening of vinculin focal adhesion plaques, and inhibition of ROCK reduced the formation of distinct focal adhesion plaques. Phosphorylation of focal adhesion kinase was significantly reduced by both hyperoxia and treatment with Y-27632. Hyperoxia caused increased cell stiffness and promoted cell detachment during stretch. These effects were ameliorated by inhibition of ROCK. PMID:24289040

  9. Male Sex is Associated with a Reduced Alveolar Epithelial Sodium Transport

    PubMed Central

    Kaltofen, Till; Haase, Melanie; Thome, Ulrich H.; Laube, Mandy

    2015-01-01

    Respiratory distress syndrome (RDS) is the most frequent pulmonary complication in preterm infants. RDS incidence differs between genders, which has been called the male disadvantage. Besides maturation of the surfactant system, Na+ transport driven alveolar fluid clearance is crucial for the prevention of RDS. Na+ transport is mediated by the epithelial Na+ channel (ENaC) and the Na,K-ATPase, therefore potential differences in their expression or activity possibly contribute to the gender imbalance observed in RDS. Fetal distal lung epithelial (FDLE) cells of rat fetuses were separated by sex and analyzed regarding expression and activity of the Na+ transporters. Ussing chamber experiments showed a higher baseline short-circuit current (ISC) and amiloride-sensitive ΔISC in FDLE cells of female origin. In addition, maximal amiloride-sensitive ΔISC and maximal ouabain-sensitive ΔISC of female cells were higher when measured in the presence of a permeabilized basolateral or apical membrane, respectively. The number of FDLE cells per fetus recoverable during cell isolation was also significantly higher in females. In addition, lung wet-to-dry weight ratio was lower in fetal and newborn female pups. Female derived FDLE cells had higher mRNA levels of the ENaC- and Na,K-ATPase subunits. Furthermore, estrogen (ER) and progesterone receptor (PR) mRNA levels were higher in female cells, which might render female cells more responsive, while concentrations of placenta-derived sex steroids do not differ between both genders during fetal life. Inhibition of ER-β abolished the sex differences in Na+ transport and female cells were more responsive to estradiol stimulation. In conclusion, a higher alveolar Na+ transport, possibly attributable to a higher expression of hormone receptors in female FDLE cells, provides an explanation for the well known sex-related difference in RDS occurrence and outcome. PMID:26291531

  10. Effects of PPARγ ligands on TGF-β1-induced epithelial-mesenchymal transition in alveolar epithelial cells

    PubMed Central

    2010-01-01

    Background Transforming growth factor β1 (TGF-β1)-mediated epithelial mesenchymal transition (EMT) of alveolar epithelial cells (AEC) may contribute to lung fibrosis. Since PPARγ ligands have been shown to inhibit fibroblast activation by TGF-β1, we assessed the ability of the thiazolidinediones rosiglitazone (RGZ) and ciglitazone (CGZ) to regulate TGF-β1-mediated EMT of A549 cells, assessing changes in cell morphology, and expression of cell adhesion molecules E-cadherin (epithelial cell marker) and N-cadherin (mesenchymal cell marker), and collagen 1α1 (COL1A1), CTGF and MMP-2 mRNA. Methods Serum-deprived A549 cells (human AEC cell line) were pre-incubated with RGZ and CGZ (1 - 30 μM) in the absence or presence of the PPARγ antagonist GW9662 (10 μM) before TGFβ-1 (0.075-7.5 ng/ml) treatment for up to 72 hrs. Changes in E-cadherin, N-cadherin and phosphorylated Smad2 and Smad3 levels were analysed by Western blot, and changes in mRNA levels including COL1A1 assessed by RT-PCR. Results TGFβ-1 (2.5 ng/ml)-induced reductions in E-cadherin expression were associated with a loss of epithelial morphology and cell-cell contact. Concomitant increases in N-cadherin, MMP-2, CTGF and COL1A1 were evident in predominantly elongated fibroblast-like cells. Neither RGZ nor CGZ prevented TGFβ1-induced changes in cell morphology, and PPARγ-dependent inhibitory effects of both ligands on changes in E-cadherin were only evident at submaximal TGF-β1 (0.25 ng/ml). However, both RGZ and CGZ inhibited the marked elevation of N-cadherin and COL1A1 induced by TGF-β1 (2.5 ng/ml), with effects on COL1A1 prevented by GW9662. Phosphorylation of Smad2 and Smad3 by TGF-β1 was not inhibited by RGZ or CGZ. Conclusions RGZ and CGZ inhibited profibrotic changes in TGF-β1-stimulated A549 cells independently of inhibition of Smad phosphorylation. Their inhibitory effects on changes in collagen I and E-cadherin, but not N-cadherin or CTGF, appeared to be PPARγ-dependent. Further

  11. Apolipoprotein A1 Inhibits TGF-β1–Induced Epithelial-to-Mesenchymal Transition of Alveolar Epithelial Cells

    PubMed Central

    Baek, Ae Rin; Lee, Ji Min; Seo, Hyun Jung; Park, Jong Sook; Lee, June Hyuk; Jang, An Soo; Kim, Do Jin; Koh, Eun Suk; Uh, Soo Taek; Kim, Yong Hoon; Park, Choon Sik

    2016-01-01

    Background Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by the accumulation of excessive fibroblasts and myofibroblasts in the extracellular matrix. The transforming growth factor β1 (TGF-β1)–induced epithelial-to-mesenchymal transition (EMT) is thought to be a possible source of fibroblasts/myofibroblasts in IPF lungs. We have previously reported that apolipoprotein A1 (ApoA1) has anti-fibrotic activity in experimental lung fibrosis. In this study, we determine whether ApoA1 modulates TGF-β1–induced EMT in experimental lung fibrosis and clarify its mechanism of action. Methods The A549 alveolar epithelial cell line was treated with TGF-β1 with or without ApoA1. Morphological changes and expression of EMT-related markers, including E-cadherin, N-cadherin, and α-smooth muscle actin were evaluated. Expressions of Smad and non-Smad mediators and TGF-β1 receptor type 1 (TβRI) and type 2 (TβRII) were measured. The silica-induced lung fibrosis model was established using ApoA1 overexpressing transgenic mice. Results TGF-β1–treated A549 cells were changed to the mesenchymal morphology with less E-cadherin and more N-cadherin expression. The addition of ApoA1 inhibited the TGF-β1–induced change of the EMT phenotype. ApoA1 inhibited the TGF-β1–induced increase in the phosphorylation of Smad2 and 3 as well as that of ERK and p38 mitogen-activated protein kinase mediators. In addition, ApoA1 reduced the TGF-β1–induced increase in TβRI and TβRII expression. In a mouse model of silica-induced lung fibrosis, ApoA1 overexpression reduced the silica-mediated effects, which were increased N-cadherin and decreased E-cadherin expression in the alveolar epithelium. Conclusion Our data demonstrate that ApoA1 inhibits TGF-β1–induced EMT in experimental lung fibrosis. PMID:27433174

  12. Nanomaterial interactions with and trafficking across the lung alveolar epithelial barrier: implications for health effects of air-pollution particles

    PubMed Central

    Yacobi, Nazanin R.; Fazllolahi, Farnoosh; Kim, Yong Ho; Sipos, Arnold; Borok, Zea; Kim, Kwang-Jin

    2014-01-01

    Studies on the health effects of air-pollution particles suggest that injury may result from inhalation of airborne ultrafine particles (<100 nm in diameter). Engineered nanomaterials (<100 nm in at least one dimension) may also be harmful if inhaled. Nanomaterials deposited on the respiratory epithelial tract are thought to cross the air-blood barrier, especially via the expansive alveolar region, into the systemic circulation to reach end organs (e.g., myocardium, liver, pancreas, kidney, and spleen). Since ambient ultrafine particles are difficult to track, studies of defined engineered nanomaterials have been used to obtain valuable information on how nanomaterials interact with and traffic across the air-blood barrier of mammalian lungs. Since specific mechanistic information on how nanomaterials interact with the lung is difficult to obtain using in vivo or ex vivo lungs due to their complex anatomy, in vitro alveolar epithelial models have been of considerable value in determining nanomaterial-lung interactions. In this review, we provide information on mechanisms underlying lung alveolar epithelial injury caused by various nanomaterials and on nanomaterial trafficking across alveolar epithelium that may lead to end-organ injury. PMID:25568662

  13. Azithromycin increases phagocytosis of apoptotic bronchial epithelial cells by alveolar macrophages.

    PubMed

    Hodge, S; Hodge, G; Brozyna, S; Jersmann, H; Holmes, M; Reynolds, P N

    2006-09-01

    Chronic obstructive pulmonary disease (COPD) is associated with increased apoptosis and defective phagocytosis in the airway. As uncleared cells can undergo secondary necrosis and perpetuate inflammation, strategies to improve clearance would have therapeutic significance. There is evidence that the 15-member macrolide antibiotic azithromycin has anti-inflammatory properties. Its effects may be increased in the lung due to its ability to reach high concentrations in alveolar macrophages (AMs). The present study investigated the effects of low-dose (500 ng x mL(-1)) azithromycin on the phagocytosis of apoptotic bronchial epithelial cells and neutrophils by AMs. Flow cytometry was applied to measure phagocytosis and receptors involved in AM recognition of apoptotic cells. Cytokines were investigated using cytometric bead array. Baseline phagocytosis was reduced in COPD subjects compared with controls. Azithromycin significantly improved the phagocytosis of epithelial cells or neutrophils by AMs from COPD subjects by 68 and 38%, respectively, often up to levels comparable with controls. The increase in phagocytosis was partially inhibited by phosphatidylserine, implicating the phosphatidylserine pathway in the pro-phagocytic effects of azithromycin. Azithromycin had no effect on other recognition molecules (granulocyte-macrophage colony-stimulating factor, CD44, CD31, CD36, CD91, alphavbeta3 integrin). At higher doses, azithromycin decreased levels of pro-inflammatory cytokines. Thus, low-dose azithromycin therapy could provide an adjunct therapeutic option in chronic obstructive pulmonary disease. PMID:16737992

  14. Physiological and biochemical markers of alveolar epithelial barrier dysfunction in perfused human lungs

    PubMed Central

    Frank, James A.; Briot, Raphael; Lee, Jae Woo; Ishizaka, Akitoshi; Uchida, Tokujiro; Matthay, Michael A.

    2009-01-01

    To study air space fluid clearance (AFC) under conditions that resemble the clinical setting of pulmonary edema in patients, we developed a new perfused human lung preparation. We measured AFC in 20 human lungs rejected for transplantation and determined the contribution of AFC to lung fluid balance. AFC was then compared with air space and perfusate levels of a biological marker of epithelial injury. The majority of human lungs rejected for transplant had intact basal (75%) and β2-adrenergic agonist-stimulated (70%) AFC. For lungs with both basal and stimulated AFC, the basal AFC rate was 19 ± 10%/h, and the β2-adrenergic-stimulated AFC rate was 43 ± 13%/h. Higher rates of AFC were associated with less lung weight gain (Pearson coefficient −0.90, P < 0.0001). Air space and perfusate levels of the type I pneumocyte marker receptor for advanced glycation end products (RAGE) were threefold and sixfold higher, respectively, in lungs without basal AFC compared with lungs with AFC (P < 0.05). These data show that preserved AFC is a critical determinant of favorable lung fluid balance in the perfused human lung, raising the possibility that β2-agonist therapy to increase edema fluid clearance may be of value for patients with acute lung injury and pulmonary edema. Also, although additional studies are needed, a biological marker of alveolar epithelial injury may be useful clinically in predicting preserved AFC. PMID:17351061

  15. Effects of Pseudomonas aeruginosa elastase on alveolar epithelial permeability in guinea pigs

    SciTech Connect

    Azghani, A.O.; Connelly, J.C.; Peterson, B.T.; Gray, L.D.; Collins, M.L.; Johnson, A.R. )

    1990-02-01

    Elastase-deficient mutants of Pseudomonas aeruginosa are less virulent than the wild type and are easily cleared from the lungs of guinea pigs. The effect of P. aeruginosa elastase on lung epithelium, however, is not yet understood. We addressed the hypothesis that breach of the epithelial barrier by elastase from P. aeruginosa allows invading organisms and toxic substances to penetrate the interstitium. We measured the clearance of aerosolized technetium-labeled albumin (molecular weight, 69,000) from the lungs of anesthetized guinea pigs with the aid of a gamma camera and a dedicated computer. Aerosols of the elastase (0.1 to 5 micrograms) increased the rate of clearance of labeled albumin from the lungs in proportion to the elastase dose. Electron microscopic studies using horseradish peroxidase as a tracer revealed that elastase interrupts intercellular tight junctions of the epithelial lining, thereby increasing the permeability to macromolecules. The amounts of elastase used in this report did not cause interstitial or alveolar edema, as determined by both postmortem extravascular lung water volume measurement and morphological examination. The data indicate that the elastase is a potentially important virulence factor in acute lung infection.

  16. Is bone transplantation the gold standard for repair of alveolar bone defects?

    PubMed

    Raposo-Amaral, Cassio Eduardo; Bueno, Daniela Franco; Almeida, Ana Beatriz; Jorgetti, Vanda; Costa, Cristiane Cabral; Gouveia, Cecília Helena; Vulcano, Luiz Carlos; Fanganiello, Roberto D; Passos-Bueno, Maria Rita; Alonso, Nivaldo

    2014-01-01

    New strategies to fulfill craniofacial bone defects have gained attention in recent years due to the morbidity of autologous bone graft harvesting. We aimed to evaluate the in vivo efficacy of bone tissue engineering strategy using mesenchymal stem cells associated with two matrices (bovine bone mineral and α-tricalcium phosphate), compared to an autologous bone transfer. A total of 28 adult, male, non-immunosuppressed Wistar rats underwent a critical-sized osseous defect of 5 mm diameter in the alveolar region. Animals were divided into five groups. Group 1 (n = 7) defects were repaired with autogenous bone grafts; Group 2 (n = 5) defects were repaired with bovine bone mineral free of cells; Group 3 (n = 5) defects were repaired with bovine bone mineral loaded with mesenchymal stem cells; Group 4 (n = 5) defects were repaired with α-tricalcium phosphate free of cells; and Group 5 (n = 6) defects were repaired with α-tricalcium phosphate loaded with mesenchymal stem cells. Groups 2-5 were compared to Group 1, the reference group. Healing response was evaluated by histomorphometry and computerized tomography. Histomorphometrically, Group 1 showed 60.27% ± 16.13% of bone in the defect. Groups 2 and 3 showed 23.02% ± 8.6% (p = 0.01) and 38.35% ± 19.59% (p = 0.06) of bone in the defect, respectively. Groups 4 and 5 showed 51.48% ± 11.7% (p = 0.30) and 61.80% ± 2.14% (p = 0.88) of bone in the defect, respectively. Animals whose bone defects were repaired with α-tricalcium phosphate and mesenchymal stem cells presented the highest bone volume filling the defects; both were not statistically different from autogenous bone. PMID:24551445

  17. Is bone transplantation the gold standard for repair of alveolar bone defects?

    PubMed Central

    Raposo-Amaral, Cassio Eduardo; Bueno, Daniela Franco; Almeida, Ana Beatriz; Jorgetti, Vanda; Costa, Cristiane Cabral; Gouveia, Cecília Helena; Vulcano, Luiz Carlos; Fanganiello, Roberto D; Passos-Bueno, Maria Rita

    2014-01-01

    New strategies to fulfill craniofacial bone defects have gained attention in recent years due to the morbidity of autologous bone graft harvesting. We aimed to evaluate the in vivo efficacy of bone tissue engineering strategy using mesenchymal stem cells associated with two matrices (bovine bone mineral and α-tricalcium phosphate), compared to an autologous bone transfer. A total of 28 adult, male, non-immunosuppressed Wistar rats underwent a critical-sized osseous defect of 5 mm diameter in the alveolar region. Animals were divided into five groups. Group 1 (n = 7) defects were repaired with autogenous bone grafts; Group 2 (n = 5) defects were repaired with bovine bone mineral free of cells; Group 3 (n = 5) defects were repaired with bovine bone mineral loaded with mesenchymal stem cells; Group 4 (n = 5) defects were repaired with α-tricalcium phosphate free of cells; and Group 5 (n = 6) defects were repaired with α-tricalcium phosphate loaded with mesenchymal stem cells. Groups 2–5 were compared to Group 1, the reference group. Healing response was evaluated by histomorphometry and computerized tomography. Histomorphometrically, Group 1 showed 60.27% ± 16.13% of bone in the defect. Groups 2 and 3 showed 23.02% ± 8.6% (p = 0.01) and 38.35% ± 19.59% (p = 0.06) of bone in the defect, respectively. Groups 4 and 5 showed 51.48% ± 11.7% (p = 0.30) and 61.80% ± 2.14% (p = 0.88) of bone in the defect, respectively. Animals whose bone defects were repaired with α-tricalcium phosphate and mesenchymal stem cells presented the highest bone volume filling the defects; both were not statistically different from autogenous bone. PMID:24551445

  18. Inter-alpha-trypsin inhibitor promotes bronchial epithelial repair after injury through vitronectin binding.

    PubMed

    Adair, Jennifer E; Stober, Vandy; Sobhany, Mack; Zhuo, Lisheng; Roberts, John D; Negishi, Masahiko; Kimata, Koji; Garantziotis, Stavros

    2009-06-19

    Pulmonary epithelial injury is central to the pathogenesis of many lung diseases, such as asthma, pulmonary fibrosis, and the acute respiratory distress syndrome. Regulated epithelial repair is crucial for lung homeostasis and prevents scar formation and inflammation that accompany dysregulated healing. The extracellular matrix (ECM) plays an important role in epithelial repair after injury. Vitronectin is a major ECM component that promotes epithelial repair. However, the factors that modify cell-vitronectin interactions after injury and help promote epithelial repair are not well studied. Inter-alpha-trypsin inhibitor (IaI) is an abundant serum protein. IaI heavy chains contain von Willebrand A domains that can bind the arginine-glycine-aspartate domain of vitronectin. We therefore hypothesized that IaI can bind vitronectin and promote vitronectin-induced epithelial repair after injury. We show that IaI binds vitronectin at the arginine-glycine-aspartate site, thereby promoting epithelial adhesion and migration in vitro. Furthermore, we show that IaI-deficient mice have a dysregulated response to epithelial injury in vivo, consisting of decreased proliferation and epithelial metaplasia. We conclude that IaI interacts not only with hyaluronan, as previously reported, but also other ECM components like vitronectin and is an important regulator of cellular repair after injury. PMID:19395377

  19. Translocation of Functionalized Multi-Walled Carbon Nanotubes across Human Pulmonary Alveolar Epithelium: Dominant Role of Epithelial Type 1 Cells.

    PubMed

    Ruenraroengsak, Pakatip; Chen, Shu; Hu, Sheng; Melbourne, Jodie; Sweeney, Sinbad; Thorley, Andrew J; Skepper, Jeremy N; Shaffer, Milo S P; Tetley, Teresa D; Porter, Alexandra E

    2016-05-24

    Uptake and translocation of short functionalized multi-walled carbon nanotubes (short-fMWCNTs) through the pulmonary respiratory epithelial barrier depend on physicochemical property and cell type. Two monoculture models, immortalized human alveolar epithelial type 1 (TT1) cells and primary human alveolar epithelial type 2 cells (AT2), which constitute the alveolar epithelial barrier, were employed to investigate the uptake and transport of 300 and 700 nm in length, poly(4-vinylpyridine)-functionalized, multi-walled carbon nanotubes (p(4VP)-MWCNTs) using quantitative imaging and spectroscopy techniques. The p(4VP)-MWCNT exhibited no toxicity on TT1 and AT2 cells, but significantly decreased barrier integrity (*p < 0.01). Uptake of p(4VP)-MWCNTs was observed in 70% of TT1 cells, correlating with compromised barrier integrity and basolateral p(4VP)-MWCNT translocation. There was a small but significantly greater uptake of 300 nm p(4VP)-MWCNTs than 700 nm p(4VP)-MWCNTs by TT1 cells. Up to 3% of both the 300 and 700 nm p(4VP)-MWCNTs reach the basal chamber; this relatively low amount arose because the supporting transwell membrane minimized the amount of p(4VP)-MWCNT translocating to the basal chamber, seen trapped between the basolateral cell membrane and the membrane. Only 8% of AT2 cells internalized p(4VP)-MWCNT, accounting for 17% of applied p(4VP)-MWCNT), with transient effects on barrier function, which initially fell then returned to normal; there was no MWCNT basolateral translocation. The transport rate was MWCNT length modulated. The comparatively lower p(4VP)-MWCNT uptake by AT2 cells is proposed to reflect a primary barrier effect of type 2 cell secretions and the functional differences between the type 1 and type 2 alveolar epithelial cells. PMID:27035850

  20. Mitochondria-targeted Ogg1 and Aconitase-2 Prevent Oxidant-induced Mitochondrial DNA Damage in Alveolar Epithelial Cells*

    PubMed Central

    Kim, Seok-Jo; Cheresh, Paul; Williams, David; Cheng, Yuan; Ridge, Karen; Schumacker, Paul T.; Weitzman, Sigmund; Bohr, Vilhelm A.; Kamp, David W.

    2014-01-01

    Mitochondria-targeted human 8-oxoguanine DNA glycosylase (mt-hOgg1) and aconitase-2 (Aco-2) each reduce oxidant-induced alveolar epithelial cell (AEC) apoptosis, but it is unclear whether protection occurs by preventing AEC mitochondrial DNA (mtDNA) damage. Using quantitative PCR-based measurements of mitochondrial and nuclear DNA damage, mtDNA damage was preferentially noted in AEC after exposure to oxidative stress (e.g. amosite asbestos (5–25 μg/cm2) or H2O2 (100–250 μm)) for 24 h. Overexpression of wild-type mt-hOgg1 or mt-long α/β 317–323 hOgg1 mutant incapable of DNA repair (mt-hOgg1-Mut) each blocked A549 cell oxidant-induced mtDNA damage, mitochondrial p53 translocation, and intrinsic apoptosis as assessed by DNA fragmentation and cleaved caspase-9. In contrast, compared with controls, knockdown of Ogg1 (using Ogg1 shRNA in A549 cells or primary alveolar type 2 cells from ogg1−/− mice) augmented mtDNA lesions and intrinsic apoptosis at base line, and these effects were increased further after exposure to oxidative stress. Notably, overexpression of Aco-2 reduced oxidant-induced mtDNA lesions, mitochondrial p53 translocation, and apoptosis, whereas siRNA for Aco-2 (siAco-2) enhanced mtDNA damage, mitochondrial p53 translocation, and apoptosis. Finally, siAco-2 attenuated the protective effects of mt-hOgg1-Mut but not wild-type mt-hOgg1 against oxidant-induced mtDNA damage and apoptosis. Collectively, these data demonstrate a novel role for mt-hOgg1 and Aco-2 in preserving AEC mtDNA integrity, thereby preventing oxidant-induced mitochondrial dysfunction, p53 mitochondrial translocation, and intrinsic apoptosis. Furthermore, mt-hOgg1 chaperoning of Aco-2 in preventing oxidant-mediated mtDNA damage and apoptosis may afford an innovative target for the molecular events underlying oxidant-induced toxicity. PMID:24429287

  1. Asbestos-Induced Alveolar Epithelial Cell Apoptosis. The Role of Endoplasmic Reticulum Stress Response

    PubMed Central

    Liu, Gang; Cheresh, Paul; Kim, Seok-Jo; Mueller, Amanda; Lam, Anna P; Trejo, Humberto; Williams, David; Tulasiram, Sandhya; Baker, Margaret; Ridge, Karen; Chandel, Navdeep S.; Beri, Rohinee

    2013-01-01

    Asbestos exposure results in pulmonary fibrosis (asbestosis) and malignancies (bronchogenic lung cancer and mesothelioma) by mechanisms that are not fully understood. Alveolar epithelial cell (AEC) apoptosis is important in the development of pulmonary fibrosis after exposure to an array of toxins, including asbestos. An endoplasmic reticulum (ER) stress response and mitochondria-regulated (intrinsic) apoptosis occur in AECs of patients with idiopathic pulmonary fibrosis, a disease with similarities to asbestosis. Asbestos induces AEC intrinsic apoptosis, but the role of the ER is unclear. The objective of this study was to determine whether asbestos causes an AEC ER stress response that promotes apoptosis. Using human A549 and rat primary isolated alveolar type II cells, amosite asbestos fibers increased AEC mRNA and protein expression of ER stress proteins involved in the unfolded protein response, such as inositol-requiring kinase (IRE) 1 and X-box–binding protein-1, as well as ER Ca²2+ release ,as assessed by a FURA-2 assay. Eukarion-134, a superoxide dismutase/catalase mimetic, as well as overexpression of Bcl-XL in A549 cells each attenuate asbestos-induced AEC ER stress (IRE-1 and X-box–binding protein-1 protein expression; ER Ca²2+ release) and apoptosis. Thapsigargin, a known ER stress inducer, augments AEC apoptosis, and eukarion-134 or Bcl-XL overexpression are protective. Finally, 4-phenylbutyric acid, a chemical chaperone that attenuates ER stress, blocks asbestos- and thapsigargin-induced AEC IRE-1 protein expression, but does not reduce ER Ca²2+ release or apoptosis. These results show that asbestos triggers an AEC ER stress response and subsequent intrinsic apoptosis that is mediated in part by ER Ca²2+ release. PMID:23885834

  2. Asbestos-induced alveolar epithelial cell apoptosis. The role of endoplasmic reticulum stress response.

    PubMed

    Kamp, David W; Liu, Gang; Cheresh, Paul; Kim, Seok-Jo; Mueller, Amanda; Lam, Anna P; Trejo, Humberto; Williams, David; Tulasiram, Sandhya; Baker, Margaret; Ridge, Karen; Chandel, Navdeep S; Beri, Rohinee

    2013-12-01

    Asbestos exposure results in pulmonary fibrosis (asbestosis) and malignancies (bronchogenic lung cancer and mesothelioma) by mechanisms that are not fully understood. Alveolar epithelial cell (AEC) apoptosis is important in the development of pulmonary fibrosis after exposure to an array of toxins, including asbestos. An endoplasmic reticulum (ER) stress response and mitochondria-regulated (intrinsic) apoptosis occur in AECs of patients with idiopathic pulmonary fibrosis, a disease with similarities to asbestosis. Asbestos induces AEC intrinsic apoptosis, but the role of the ER is unclear. The objective of this study was to determine whether asbestos causes an AEC ER stress response that promotes apoptosis. Using human A549 and rat primary isolated alveolar type II cells, amosite asbestos fibers increased AEC mRNA and protein expression of ER stress proteins involved in the unfolded protein response, such as inositol-requiring kinase (IRE) 1 and X-box-binding protein-1, as well as ER Ca²(2+) release ,as assessed by a FURA-2 assay. Eukarion-134, a superoxide dismutase/catalase mimetic, as well as overexpression of Bcl-XL in A549 cells each attenuate asbestos-induced AEC ER stress (IRE-1 and X-box-binding protein-1 protein expression; ER Ca²(2+) release) and apoptosis. Thapsigargin, a known ER stress inducer, augments AEC apoptosis, and eukarion-134 or Bcl-XL overexpression are protective. Finally, 4-phenylbutyric acid, a chemical chaperone that attenuates ER stress, blocks asbestos- and thapsigargin-induced AEC IRE-1 protein expression, but does not reduce ER Ca²(2+) release or apoptosis. These results show that asbestos triggers an AEC ER stress response and subsequent intrinsic apoptosis that is mediated in part by ER Ca²(2+) release. PMID:23885834

  3. Breakdown of Epithelial Barrier Integrity and Overdrive Activation of Alveolar Epithelial Cells in the Pathogenesis of Acute Respiratory Distress Syndrome and Lung Fibrosis

    PubMed Central

    Yanagi, Shigehisa; Tsubouchi, Hironobu; Miura, Ayako; Matsumoto, Nobuhiro; Nakazato, Masamitsu

    2015-01-01

    Individual alveolar epithelial cells (AECs) collaboratively form a tight barrier between atmosphere and fluid-filled tissue to enable normal gas exchange. The tight junctions of AECs provide intercellular sealing and are integral to the maintenance of the AEC barrier integrity. Disruption and failure of reconstitution of AEC barrier result in catastrophic consequences, leading to alveolar flooding and subsequent devastating fibrotic scarring. Recent evidences reveal that many of the fibrotic lung diseases involve AECs both as a frequent target of injury and as a driver of ongoing pathological processes. Aberrantly activated AECs express most of the growth factors and chemokines responsible for the proliferation, migration, and activation of fibroblasts. Current evidences suggest that AECs may acquire overdrive activation in the initial step of fibrosis by several mechanisms, including abnormal recapitulation of the developmental pathway, defects of the molecules essential for epithelial integrity, and acceleration of aging-related properties. Among these initial triggering events, epithelial Pten, a multiple phosphatase that negatively regulates the PI3K/Akt pathway and is crucial for lung development, is essential for the prevention of alveolar flooding and lung fibrosis through the regulation of AEC barrier integrity after injury. Reestablishment of AEC barrier integrity also involves the deployment of specialized stem/progenitor cells. PMID:26523279

  4. Autophagy protects type II alveolar epithelial cells from Mycobacterium tuberculosis infection

    SciTech Connect

    Guo, Xu-Guang; Ji, Tian-Xing; Xia, Yong; Ma, Yue-Yun

    2013-03-08

    Highlights: ► We investigated the protective effect of autophagy pathway against MTB infection. ► MTB-infected A549 cells had higher LDH release. ► Inhibition of autophagy signaling significantly enhanced the MTB-induced necrosis. ► Autophagy prevents apoptosis and promotes cell survival in infected cells. -- Abstract: This study was designed to investigate the protective effect of the autophagy signaling pathway against Mycobacterium tuberculosis infection in type II alveolar epithelial cells. An in vitro M. tuberculosis system was established using human A549 cells. Infection-induced changes in the expression of the autophagic marker LC3 were assessed by reverse transcription-PCR and Western blotting. Morphological changes in autophagosomes were detected by transmission electron microscopy (TEM). The function of the autophagy signaling pathway during infection was assessed by measuring the level of cell death and the amount of lactate dehydrogenase (LDH) released in the presence or absence of the inhibitor 3-methyladenine (3-MA). In addition, effects on LDH release were assessed after the siRNA-mediated knockdown of the essential autophagosomal structural membrane protein Atg5. LC3 mRNA expression was significantly reduced in M.tuberculosis-infected A549 cells (16888.76 ± 1576.34 vs. uninfected: 12744.29 ± 1089.37; P < 0.05). TEM revealed M.tuberculosis bacilli-containing compartments that were surrounded by double membranes characteristic of the autophagic process. M.tuberculosis-infected A549 cells released more LDH (1.45 ± 0.12 vs. uninfected: 0.45 ± 0.04; P < 0.05). The inhibition of autophagy signaling significantly enhanced M.tuberculosis-induced necrosis (3-MA: 75 ± 5% vs. untreated: 15 ± 1%; P < 0.05) and LDH release (3-MA: 2.50 ± 0.24 vs. untreated: 0.45 ± 0.04; Atg5 knockdown: 3.19 ± 0.29 vs. untreated: 1.28 ± 0.11; P < 0.05). Our results indicate that autophagy signaling pathway prevents apoptosis in type II alveolar epithelial cells

  5. Sulfidation of silver nanowires inside human alveolar epithelial cells: a potential detoxification mechanism

    NASA Astrophysics Data System (ADS)

    Chen, Shu; Goode, Angela E.; Sweeney, Sinbad; Theodorou, Ioannis G.; Thorley, Andrew J.; Ruenraroengsak, Pakatip; Chang, Yan; Gow, Andrew; Schwander, Stephan; Skepper, Jeremy; Zhang, Junfeng (Jim); Shaffer, Milo S.; Chung, Kian Fan; Tetley, Teresa D.; Ryan, Mary P.; Porter, Alexandra E.

    2013-09-01

    Silver nanowires (AgNWs) are being developed for use in optoelectronics. However before widespread usage, it is crucial to determine their potential effects on human health. It is accepted that Ag nanoparticles (AgNPs) exert toxic effects by releasing Ag+ ions, but much less is known about whether Ag+ reacts with compounds, or any downstream bioactive effects of transformed AgNPs. Analytical high-resolution transmission electron microscopy has been employed to elucidate cellular uptake and reactivity of AgNWs inside human alveolar epithelial type 1-like cells. AgNWs were observed in the cytoplasm and membrane-bound vesicles, and precipitation of Ag2S within the cell occurred after 1 h exposure. Cell viability studies showed no evidence of cytotoxicity and reactive oxygen species were not observed on exposure of cells to AgNWs. We suggest that Ag2S formation acts as a `trap' for free Ag+, significantly limiting short-term toxicological effects - with important consequences for the safety of Ag-nanomaterials to human health.Silver nanowires (AgNWs) are being developed for use in optoelectronics. However before widespread usage, it is crucial to determine their potential effects on human health. It is accepted that Ag nanoparticles (AgNPs) exert toxic effects by releasing Ag+ ions, but much less is known about whether Ag+ reacts with compounds, or any downstream bioactive effects of transformed AgNPs. Analytical high-resolution transmission electron microscopy has been employed to elucidate cellular uptake and reactivity of AgNWs inside human alveolar epithelial type 1-like cells. AgNWs were observed in the cytoplasm and membrane-bound vesicles, and precipitation of Ag2S within the cell occurred after 1 h exposure. Cell viability studies showed no evidence of cytotoxicity and reactive oxygen species were not observed on exposure of cells to AgNWs. We suggest that Ag2S formation acts as a `trap' for free Ag+, significantly limiting short-term toxicological effects

  6. Primary human alveolar epithelial cells can elicit the transendothelial migration of CD14+ monocytes and CD3+ lymphocytes

    PubMed Central

    Eghtesad, M; Jackson, H E; Cunningham, A C

    2001-01-01

    The ability of freshly isolated primary human alveolar epithelial cells (type II pneumocytes) to induce leucocyte migration across an endothelial monolayer was investigated. Three-way factorial analysis of variance (anova) demonstrated that resting alveolar endothelial cells (AEC) could produce detectable quantities of monocyte chemoattractant protein 1 (MCP-1), which was upregulated in response to tumour necrosis factor-α (TNF-α) in a dose- and time-dependent fashion. Interferon-γ (IFN-γ) had no significant effect on this process. TNF-α and IFN-γ both induced AEC to provoke migration of CD14+ monocytes and CD3+ lymphocytes across endothelium. IFN-γ and TNF-α synergized in their ability to induce production of T lymphocyte, but not monocyte, chemoattractants from AEC. Leucocyte transendothelial migration was inhibited by anti-MCP-1 neutralizing antibody and by heparin, a polyanionic glycosaminoglycan (GAG). These data suggest that human AEC play a role in the multiple mechanisms that facilitate monocyte and T lymphocyte migration into the alveolar compartment of the lung under homeostasis and inflammatory conditions. One of these mechanisms is mediated via constitutive MCP-1 production by alveolar epithelial cells, which is upregulated by TNF-α. PMID:11260320

  7. Effect of P2X7 receptor knockout on AQP-5 expression of type I alveolar epithelial cells.

    PubMed

    Ebeling, Georg; Bläsche, Robert; Hofmann, Falk; Augstein, Antje; Kasper, Michael; Barth, Kathrin

    2014-01-01

    P2X7 receptors, ATP-gated cation channels, are specifically expressed in alveolar epithelial cells. The pathophysiological function of this lung cell type, except a recently reported putative involvement in surfactant secretion, is unknown. In addition, P2X7 receptor-deficient mice show reduced inflammation and lung fibrosis after exposure with bleomycin. To elucidate the role of the P2X7 receptor in alveolar epithelial type I cells we characterized the pulmonary phenotype of P2X7 receptor knockout mice by using immunohistochemistry, western blot analysis and real-time RT PCR. No pathomorphological signs of fibrosis were found. Results revealed, however, a remarkable loss of aquaporin-5 protein and mRNA in young knockout animals. Additional in vitro experiments with bleomycin treated precision cut lung slices showed a greater sensitivity of the P2X7 receptor knockout mice in terms of aquaporin-5 reduction as wild type animals. Finally, P2X7 receptor function was examined by using the alveolar epithelial cell lines E10 and MLE-12 for stimulation experiments with bleomycin. The in vitro activation of P2X7 receptor was connected with an increase of aquaporin-5, whereas the inhibition of the receptor with oxidized ATP resulted in down regulation of aquaporin-5. The early loss of aquaporin-5 which can be found in different pulmonary fibrosis models does not implicate a specific pathogenetic role during fibrogenesis. PMID:24941004

  8. Human Vγ9Vδ2-T cells efficiently kill influenza virus-infected lung alveolar epithelial cells

    PubMed Central

    Li, Hong; Xiang, Zheng; Feng, Ting; Li, Jinrong; Liu, Yinping; Fan, Yingying; Lu, Qiao; Yin, Zhongwei; Yu, Meixing; Shen, Chongyang; Tu, Wenwei

    2013-01-01

    γδ-T cells play an indispensable role in host defense against different viruses, including influenza A virus. However, whether these cells have cytotoxic activity against influenza virus-infected lung alveolar epithelial cells and subsequently contribute to virus clearance remains unknown. Using influenza virus-infected A549 cells, human lung alveolar epithelial cells, we investigated the cytotoxic activity of aminobisphosphonate pamidronate (PAM)-expanded human Vγ9Vδ2-T cells and their underlying mechanisms. We found that PAM could selectively activate and expand human Vγ9Vδ2-T cells. PAM-expanded human Vγ9Vδ2-T cells efficiently killed influenza virus-infected lung alveolar epithelial cells and inhibited virus replication. The cytotoxic activity of PAM-expanded Vγ9Vδ2-T cells was dependent on cell-to-cell contact and required NKG2D activation. Perforin–granzyme B, tumor-necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas–Fas ligand (FasL) pathways were involved in their cytotoxicity. Our study suggests that targeting γδ-T cells by PAM can potentially offer an alternative option for the treatment of influenza virus. PMID:23353835

  9. Differential Regulation of Gene Expression of Alveolar Epithelial Cell Markers in Human Lung Adenocarcinoma-Derived A549 Clones

    PubMed Central

    Kondo, Hiroshi; Miyoshi, Keiko; Sakiyama, Shoji; Tangoku, Akira; Noma, Takafumi

    2015-01-01

    Stem cell therapy appears to be promising for restoring damaged or irreparable lung tissue. However, establishing a simple and reproducible protocol for preparing lung progenitor populations is difficult because the molecular basis for alveolar epithelial cell differentiation is not fully understood. We investigated an in vitro system to analyze the regulatory mechanisms of alveolus-specific gene expression using a human alveolar epithelial type II (ATII) cell line, A549. After cloning A549 subpopulations, each clone was classified into five groups according to cell morphology and marker gene expression. Two clones (B7 and H12) were further analyzed. Under serum-free culture conditions, surfactant protein C (SPC), an ATII marker, was upregulated in both H12 and B7. Aquaporin 5 (AQP5), an ATI marker, was upregulated in H12 and significantly induced in B7. When the RAS/MAPK pathway was inhibited, SPC and thyroid transcription factor-1 (TTF-1) expression levels were enhanced. After treatment with dexamethasone (DEX), 8-bromoadenosine 3′5′-cyclic monophosphate (8-Br-cAMP), 3-isobutyl-1-methylxanthine (IBMX), and keratinocyte growth factor (KGF), surfactant protein B and TTF-1 expression levels were enhanced. We found that A549-derived clones have plasticity in gene expression of alveolar epithelial differentiation markers and could be useful in studying ATII maintenance and differentiation. PMID:26167183

  10. Regulation of alveolar procoagulant activity and permeability in direct acute lung injury by lung epithelial tissue factor.

    PubMed

    Shaver, Ciara M; Grove, Brandon S; Putz, Nathan D; Clune, Jennifer K; Lawson, William E; Carnahan, Robert H; Mackman, Nigel; Ware, Lorraine B; Bastarache, Julie A

    2015-11-01

    Tissue factor (TF) initiates the extrinsic coagulation cascade in response to tissue injury, leading to local fibrin deposition. Low levels of TF in mice are associated with increased severity of acute lung injury (ALI) after intratracheal LPS administration. However, the cellular sources of the TF required for protection from LPS-induced ALI remain unknown. In the current study, transgenic mice with cell-specific deletions of TF in the lung epithelium or myeloid cells were treated with intratracheal LPS to determine the cellular sources of TF important in direct ALI. Cell-specific deletion of TF in the lung epithelium reduced total lung TF expression to 39% of wild-type (WT) levels at baseline and to 29% of WT levels after intratracheal LPS. In contrast, there was no reduction of TF with myeloid cell TF deletion. Mice lacking myeloid cell TF did not differ from WT mice in coagulation, inflammation, permeability, or hemorrhage. However, mice lacking lung epithelial TF had increased tissue injury, impaired activation of coagulation in the airspace, disrupted alveolar permeability, and increased alveolar hemorrhage after intratracheal LPS. Deletion of epithelial TF did not affect alveolar permeability in an indirect model of ALI caused by systemic LPS infusion. These studies demonstrate that the lung epithelium is the primary source of TF in the lung, contributing 60-70% of total lung TF, and that lung epithelial, but not myeloid, TF may be protective in direct ALI. PMID:25884207

  11. Effect of P2X7 Receptor Knockout on AQP-5 Expression of Type I Alveolar Epithelial Cells

    PubMed Central

    Ebeling, Georg; Bläsche, Robert; Hofmann, Falk; Augstein, Antje; Kasper, Michael; Barth, Kathrin

    2014-01-01

    P2X7 receptors, ATP-gated cation channels, are specifically expressed in alveolar epithelial cells. The pathophysiological function of this lung cell type, except a recently reported putative involvement in surfactant secretion, is unknown. In addition, P2X7 receptor-deficient mice show reduced inflammation and lung fibrosis after exposure with bleomycin. To elucidate the role of the P2X7 receptor in alveolar epithelial type I cells we characterized the pulmonary phenotype of P2X7 receptor knockout mice by using immunohistochemistry, western blot analysis and real-time RT PCR. No pathomorphological signs of fibrosis were found. Results revealed, however, a remarkable loss of aquaporin-5 protein and mRNA in young knockout animals. Additional in vitro experiments with bleomycin treated precision cut lung slices showed a greater sensitivity of the P2X7 receptor knockout mice in terms of aquaporin-5 reduction as wild type animals. Finally, P2X7 receptor function was examined by using the alveolar epithelial cell lines E10 and MLE-12 for stimulation experiments with bleomycin. The in vitro activation of P2X7 receptor was connected with an increase of aquaporin-5, whereas the inhibition of the receptor with oxidized ATP resulted in down regulation of aquaporin-5. The early loss of aquaporin-5 which can be found in different pulmonary fibrosis models does not implicate a specific pathogenetic role during fibrogenesis. PMID:24941004

  12. Culture of fetal alveolar epithelial type II cells in serum-free medium.

    PubMed

    Fraslon, C; Rolland, G; Bourbon, J R; Rieutort, M; Valenza, C

    1991-11-01

    A serum-free culture medium (defined medium = DM) was elaborated by adding to Eagle's minimum essential medium (MEM), non-essential amino acids, transferrin, putrescine, tripeptide glycyl-histidyl-lysine, somatostatin, sodium selenite, ethanolamine, phosphoethanolamine, sodium pyruvate, and metal trace elements. This medium was tested for its ability to support sustained surfactant biosynthesis in fetal alveolar epithelial type II cells. For up to 8 days, ultrastructure was maintained with persistence of lamellar inclusion bodies. Thymidine incorporation into DNA was enhanced about 50% in DM as compared with MEM, whereas it was enhanced 300% in 10% fetal bovine serum. With DM, the incorporation of tritiated choline into phosphatidylcholine (PC) of isolated surfactant material was about twice that with MEM. Deletion experiments evidenced the prominent role of pyruvate, transferrin, and selenium in the stimulation of surfactant PC biosynthesis. The addition of biotin to DM enhanced surfactant PC biosynthesis slightly and nonsurfactant PC biosynthesis markedly. The presence of nucleosides seemed unfavorable to the synthesis of surfactant PC. Type II cells responded to the addition of epidermal growth factor and insulinlike growth factor-I both by increased thymidine incorporation into DNA and choline incorporation into PC. It is concluded that DM represents a useful tool for cultivating type II cells without loss of their specialized properties and for studying the regulation of cell proliferation and surfactant biosynthesis in a controlled environment. PMID:1748624

  13. Apoptosis induced by ozone and oxysterols in human alveolar epithelial cells

    PubMed Central

    Kosmider, Beata; Loader, Joan E.; Murphy, Robert C.; Mason, Robert J.

    2010-01-01

    The mechanism of ozone-induced lung cell injury is poorly understood. One hypothesis is that ozone induces lipid peroxidation and that these peroxidased lipids produce oxidative stress and DNA damage. Oxysterols are lipid peroxide formed by the direct effect of ozone on pulmonary surfactant and cell membranes. We studied the effects of ozone and the oxysterol 5β,6β-epoxycholesterol (β-epoxide) and its metabolite cholestan-6-oxo-3,5-diol (6-oxo-3,5-diol) on human alveolar epithelial type I-like cells (ATI-like cells) and type II cells (ATII cells). Ozone and oxysterols induced apoptosis and cytotoxicity in ATI-like cells. They also generated reactive oxygen species and DNA damage. Ozone and β-epoxide were strong inducers of nuclear factor erythroid 2-related factor 2 (Nrf2), heat shock protein 70 (Hsp70) and Fos-related antigen 1 (Fra1) protein expressions. Furthermore, we found higher sensitivity of ATI-like cells than ATII cells exposed to ozone or treated with β-epoxide or 6-oxo-3,5-diol. In general the response to the cholesterol epoxides was similar to the effect of ozone. The importance of understanding the response of human ATI-like cells and ATII cells to oxysterols may be useful for further studies, because these compounds may represent useful biomarkers in other diseases. PMID:20219673

  14. Rv3351c, a Mycobacterium tuberculosis gene that affects bacterial growth and alveolar epithelial cell viability.

    PubMed

    Pavlicek, Rebecca L; Fine-Coulson, Kari; Gupta, Tuhina; Quinn, Frederick D; Posey, James E; Willby, Melisa; Castro-Garza, Jorge; Karls, Russell K

    2015-12-01

    Despite the interactions known to occur between various lower respiratory tract pathogens and alveolar epithelial cells (AECs), few reports examine factors influencing the interplay between Mycobacterium tuberculosis bacilli and AECs during infection. Importantly, in vitro studies have demonstrated that the M. tuberculosis hbha and esxA gene products HBHA and ESAT6 directly or indirectly influence AEC survival. In this report, we identify Rv3351c as another M. tuberculosis gene that impacts the fate of both the pathogen and AEC host. Intracellular replication of an Rv3351c mutant in the human AEC type II pneumocyte cell line A549 was markedly reduced relative to the complemented mutant and parent strain. Deletion of Rv3351c diminished the release of lactate dehydrogenase and decreased uptake of trypan blue vital stain by host cells infected with M. tuberculosis bacilli, suggesting attenuated cytotoxic effects. Interestingly, an isogenic hbha mutant displayed reductions in AEC killing similar to those observed for the Rv3351c mutant. This opens the possibility that multiple M. tuberculosis gene products interact with AECs. We also observed that Rv3351c aids intracellular replication and survival of M. tuberculosis in macrophages. This places Rv3351c in the same standing as HBHA and ESAT6, which are important factors in AECs and macrophages. Defining the mechanism(s) by which Rv3351c functions to aid pathogen survival within the host may lead to new drug or vaccine targets. PMID:26492080

  15. Methotrexate influx via folate transporters into alveolar epithelial cell line A549.

    PubMed

    Kawami, Masashi; Miyamoto, Mioka; Yumoto, Ryoko; Takano, Mikihisa

    2015-08-01

    Methotrexate (MTX), a drug used for the treatment of certain cancers as well as rheumatoid arthritis, sometimes induces serious interstitial lung injury. Although lung toxicity of MTX is related to its accumulation, the information concerning MTX transport in the lungs is lacking. In this study, we investigated the mechanisms underlying MTX influx into human alveolar epithelial cell line A549. MTX influx into A549 cells was time-, pH-, and temperature-dependent and showed saturation kinetics. The influx was inhibited by folic acid with IC50 values of 256.1 μM at pH 7.4 and 1.6 μM at pH 5.5, indicating that the mechanisms underlying MTX influx would be different at these pHs. We then examined the role of two folate transporters in MTX influx, reduced folate carrier (RFC) and proton-coupled folate transporter (PCFT). The expression of RFC and PCFT mRNAs in A549 cells was confirmed by reverse transcription polymerase chain reaction. In addition, MTX influx was inhibited by thiamine monophosphate, an RFC inhibitor, at pH 7.4, and by sulfasalazine, a PCFT inhibitor, at pH 5.5. These results indicated that RFC and PCFT are predominantly involved in MTX influx into A549 cells at pH 7.4 and pH 5.5, respectively. PMID:26190800

  16. Regulation and function of the two-pore-domain (K2P) potassium channel Trek-1 in alveolar epithelial cells.

    PubMed

    Schwingshackl, Andreas; Teng, Bin; Ghosh, Manik; West, Alina Nico; Makena, Patrudu; Gorantla, Vijay; Sinclair, Scott E; Waters, Christopher M

    2012-01-01

    Hyperoxia can lead to a myriad of deleterious effects in the lung including epithelial damage and diffuse inflammation. The specific mechanisms by which hyperoxia promotes these pathological changes are not completely understood. Activation of ion channels has been proposed as one of the mechanisms required for cell activation and mediator secretion. The two-pore-domain K(+) channel (K2P) Trek-1 has recently been described in lung epithelial cells, but its function remains elusive. In this study we hypothesized that hyperoxia affects expression of Trek-1 in alveolar epithelial cells and that Trek-1 is involved in regulation of cell proliferation and cytokine secretion. We found gene expression of several K2P channels in mouse alveolar epithelial cells (MLE-12), and expression of Trek-1 was significantly downregulated in cultured cells and lungs of mice exposed to hyperoxia. Similarly, proliferation cell nuclear antigen (PCNA) and Cyclin D1 expression were downregulated by exposure to hyperoxia. We developed an MLE-12 cell line deficient in Trek-1 expression using shRNA and found that Trek-1 deficiency resulted in increased cell proliferation and upregulation of PCNA but not Cyclin D1. Furthermore, IL-6 and regulated on activation normal T-expressed and presumably secreted (RANTES) secretion was decreased in Trek-1-deficient cells, whereas release of monocyte chemoattractant protein-1 was increased. Release of KC/IL-8 was not affected by Trek-1 deficiency. Overall, deficiency of Trek-1 had a more pronounced effect on mediator secretion than exposure to hyperoxia. This is the first report suggesting that the K(+) channel Trek-1 could be involved in regulation of alveolar epithelial cell proliferation and cytokine secretion, but a direct association with hyperoxia-induced changes in Trek-1 levels remains elusive. PMID:21949155

  17. The Oxygen Environment at Birth Specifies the Population of Alveolar Epithelial Stem Cells in the Adult Lung.

    PubMed

    Yee, Min; Gelein, Robert; Mariani, Thomas J; Lawrence, B Paige; O'Reilly, Michael A

    2016-05-01

    Alveolar epithelial type II cells (AEC2) maintain pulmonary homeostasis by producing surfactant, expressing innate immune molecules, and functioning as adult progenitor cells for themselves and alveolar epithelial type I cells (AEC1). How the proper number of alveolar epithelial cells is determined in the adult lung is not well understood. Here, BrdU labeling, genetic lineage tracing, and targeted expression of the anti-oxidant extracellular superoxide dismutase in AEC2s are used to show how the oxygen environment at birth influences postnatal expansion of AEC2s and AEC1s in mice. Birth into low (12%) or high (≥60%) oxygen stimulated expansion of AEC2s through self-renewal and differentiation of the airway Scgb1a1 + lineage. This non-linear or hormesis response to oxygen was specific for the alveolar epithelium because low oxygen stimulated and high oxygen inhibited angiogenesis as defined by changes in V-cadherin and PECAM (CD31). Although genetic lineage tracing studies confirmed adult AEC2s are stem cells for AEC1s, we found no evidence that postnatal growth of AEC1s were derived from self-renewing Sftpc + or the Scbg1a1 + lineage of AEC2s. Taken together, our results show how a non-linear response to oxygen at birth promotes expansion of AEC2s through two distinct lineages. Since neither lineage contributes to the postnatal expansion of AEC1s, the ability of AEC2s to function as stem cells for AEC1s appears to be restricted to the adult lung. Stem Cells 2016;34:1396-1406. PMID:26891117

  18. Reversal of elastase-induced pulmonary emphysema and promotion of alveolar epithelial cell proliferation by simvastatin in mice.

    PubMed

    Takahashi, Saeko; Nakamura, Hidetoshi; Seki, Makoto; Shiraishi, Yoshiki; Yamamoto, Miyuki; Furuuchi, Momoyo; Nakajima, Takahiro; Tsujimura, Shuko; Shirahata, Toru; Nakamura, Miho; Minematsu, Naoto; Yamasaki, Motohiro; Tateno, Hiroki; Ishizaka, Akitoshi

    2008-05-01

    Besides lowering cholesterol, statins exert multiple effects, such as anti-inflammatory activity and improvement of endothelial cell function. We examined whether simvastatin (SS) protects against the development of elastase-induced pulmonary emphysema in mice by using mean linear intercepts of alveoli (Lm) as a morphometric parameter of emphysema. After injection of intratracheal elastase on day 0, C57BL/6 mice were treated daily with SS (SS+ group) or PBS (SS- group) for 2 wk. A 21% decrease in Lm on day 7 was observed in the SS+ group vs. the SS- group. Anti-inflammatory effects of SS were observed as a decrease in percentage of neutrophils up to day 3, and in hydroxyproline concentration on day 3, in bronchoalveolar lavage fluid (BALF). SS also increased the number of proliferating cell nuclear antigen (PCNA)-positive alveolar epithelial cells between days 3 and 14. To confirm the role of statins in promoting proliferation of alveolar cells, mice were treated with SS (SS+) vs. PBS (SS-) for 12 days, starting 3 wk after elastase administration. After SS treatment, Lm decreased by 52% and PCNA-positive alveolar epithelial cells increased compared with the SS- group. Concentrations of vascular endothelial growth factor in BALF and endothelial nitric oxide synthase protein expression in pulmonary vessels tended to be higher in the SS+ group vs. the SS- group in this protocol. In conclusion, SS inhibited the development of elastase-induced pulmonary emphysema in mice. This therapeutic effect was due not only to anti-inflammation but also to the promotion of alveolar epithelial cell regeneration, partly mediated by restoring endothelial cell functions. PMID:18310229

  19. Transcriptional Profile of Mycobacterium tuberculosis Replicating in Type II Alveolar Epithelial Cells

    PubMed Central

    Peng, Zhengyu; Laal, Suman

    2015-01-01

    Mycobacterium tuberculosis (M. tb) infection is initiated by the few bacilli inhaled into the alveolus. Studies in lungs of aerosol-infected mice provided evidence for extensive replication of M. tb in non-migrating, non-antigen-presenting cells in the alveoli during the first 2–3 weeks post-infection. Alveoli are lined by type II and type I alveolar epithelial cells (AEC) which outnumber alveolar macrophages by several hundred-fold. M. tb DNA and viable M. tb have been demonstrated in AEC and other non-macrophage cells of the kidney, liver, and spleen in autopsied tissues from latently-infected subjects from TB-endemic regions indicating systemic bacterial dissemination during primary infection. M. tb have also been demonstrated to replicate rapidly in A549 cells (type II AEC line) and acquire increased invasiveness for endothelial cells. Together, these results suggest that AEC could provide an important niche for bacterial expansion and development of a phenotype that promotes dissemination during primary infection. In the current studies, we have compared the transcriptional profile of M. tb replicating intracellularly in A549 cells to that of M. tb replicating in laboratory broth, by microarray analysis. Genes significantly upregulated during intracellular residence were consistent with an active, replicative, metabolic, and aerobic state, as were genes for tryptophan synthesis and for increased virulence (ESAT-6, and ESAT-6-like genes, esxH, esxJ, esxK, esxP, and esxW). In contrast, significant downregulation of the DevR (DosR) regulon and several hypoxia-induced genes was observed. Stress response genes were either not differentially expressed or were downregulated with the exception of the heat shock response and those induced by low pH. The intra-type II AEC M. tb transcriptome strongly suggests that AEC could provide a safe haven in which M. tb can expand dramatically and disseminate from the lung prior to the elicitation of adaptive immune responses

  20. Transcriptional profile of Mycobacterium tuberculosis replicating in type II alveolar epithelial cells.

    PubMed

    Ryndak, Michelle B; Singh, Krishna K; Peng, Zhengyu; Laal, Suman

    2015-01-01

    Mycobacterium tuberculosis (M. tb) infection is initiated by the few bacilli inhaled into the alveolus. Studies in lungs of aerosol-infected mice provided evidence for extensive replication of M. tb in non-migrating, non-antigen-presenting cells in the alveoli during the first 2-3 weeks post-infection. Alveoli are lined by type II and type I alveolar epithelial cells (AEC) which outnumber alveolar macrophages by several hundred-fold. M. tb DNA and viable M. tb have been demonstrated in AEC and other non-macrophage cells of the kidney, liver, and spleen in autopsied tissues from latently-infected subjects from TB-endemic regions indicating systemic bacterial dissemination during primary infection. M. tb have also been demonstrated to replicate rapidly in A549 cells (type II AEC line) and acquire increased invasiveness for endothelial cells. Together, these results suggest that AEC could provide an important niche for bacterial expansion and development of a phenotype that promotes dissemination during primary infection. In the current studies, we have compared the transcriptional profile of M. tb replicating intracellularly in A549 cells to that of M. tb replicating in laboratory broth, by microarray analysis. Genes significantly upregulated during intracellular residence were consistent with an active, replicative, metabolic, and aerobic state, as were genes for tryptophan synthesis and for increased virulence (ESAT-6, and ESAT-6-like genes, esxH, esxJ, esxK, esxP, and esxW). In contrast, significant downregulation of the DevR (DosR) regulon and several hypoxia-induced genes was observed. Stress response genes were either not differentially expressed or were downregulated with the exception of the heat shock response and those induced by low pH. The intra-type II AEC M. tb transcriptome strongly suggests that AEC could provide a safe haven in which M. tb can expand dramatically and disseminate from the lung prior to the elicitation of adaptive immune responses

  1. Estradiol activates epithelial sodium channels in rat alveolar cells through the G protein-coupled estrogen receptor.

    PubMed

    Greenlee, Megan M; Mitzelfelt, Jeremiah D; Yu, Ling; Yue, Qiang; Duke, Billie Jeanne; Harrell, Constance S; Neigh, Gretchen N; Eaton, Douglas C

    2013-12-01

    Female sex predisposes individuals to poorer outcomes during respiratory disorders like cystic fibrosis and influenza-associated pneumonia. A common link between these disorders is dysregulation of alveolar fluid clearance via disruption of epithelial sodium channel (ENaC) activity. Recent evidence suggests that female sex hormones directly regulate expression and activity of alveolar ENaC. In our study, we identified the mechanism by which estradiol (E2) or progesterone (P4) independently regulates alveolar ENaC. Using cell-attached patch clamp, we measured ENaC single-channel activity in a rat alveolar cell line (L2) in response to overnight exposure to either E2 or P4. In contrast to P4, E2 increased ENaC channel activity (NPo) through an increase in channel open probability (Po) and an increased number of patches with observable channel activity. Apical plasma membrane abundance of the ENaC α-subunit (αENaC) more than doubled in response to E2 as determined by cell surface biotinylation. αENaC membrane abundance was approximately threefold greater in lungs from female rats in proestrus, when serum E2 is greatest, compared with diestrus, when it is lowest. Our results also revealed a significant role for the G protein-coupled estrogen receptor (Gper) to mediate E2's effects on ENaC. Overall, our results demonstrate that E2 signaling through Gper selectively activates alveolar ENaC through an effect on channel gating and channel density, the latter via greater trafficking of channels to the plasma membrane. The results presented herein implicate E2-mediated regulation of alveolar sodium channels in the sex differences observed in the pathogenesis of several pulmonary diseases. PMID:24097558

  2. Semaphorin-Plexin Signaling Controls Mitotic Spindle Orientation during Epithelial Morphogenesis and Repair.

    PubMed

    Xia, Jingjing; Swiercz, Jakub M; Bañón-Rodríguez, Inmaculada; Matković, Ivana; Federico, Giuseppina; Sun, Tianliang; Franz, Timo; Brakebusch, Cord H; Kumanogoh, Atsushi; Friedel, Roland H; Martín-Belmonte, Fernando; Gröne, Hermann-Josef; Offermanns, Stefan; Worzfeld, Thomas

    2015-05-01

    Morphogenesis, homeostasis, and regeneration of epithelial tissues rely on the accurate orientation of cell divisions, which is specified by the mitotic spindle axis. To remain in the epithelial plane, symmetrically dividing epithelial cells align their mitotic spindle axis with the plane. Here, we show that this alignment depends on epithelial cell-cell communication via semaphorin-plexin signaling. During kidney morphogenesis and repair, renal tubular epithelial cells lacking the transmembrane receptor Plexin-B2 or its semaphorin ligands fail to correctly orient the mitotic spindle, leading to severe defects in epithelial architecture and function. Analyses of a series of transgenic and knockout mice indicate that Plexin-B2 controls the cell division axis by signaling through its GTPase-activating protein (GAP) domain and Cdc42. Our data uncover semaphorin-plexin signaling as a central regulatory mechanism of mitotic spindle orientation necessary for the alignment of epithelial cell divisions with the epithelial plane. PMID:25892012

  3. Evidence of K+ channel function in epithelial cell migration, proliferation, and repair

    PubMed Central

    Girault, Alban

    2013-01-01

    Efficient repair of epithelial tissue, which is frequently exposed to insults, is necessary to maintain its functional integrity. It is therefore necessary to better understand the biological and molecular determinants of tissue regeneration and to develop new strategies to promote epithelial repair. Interestingly, a growing body of evidence indicates that many members of the large and widely expressed family of K+ channels are involved in regulation of cell migration and proliferation, key processes of epithelial repair. First, we briefly summarize the complex mechanisms, including cell migration, proliferation, and differentiation, engaged after epithelial injury. We then present evidence implicating K+ channels in the regulation of these key repair processes. We also describe the mechanisms whereby K+ channels may control epithelial repair processes. In particular, changes in membrane potential, K+ concentration, cell volume, intracellular Ca2+, and signaling pathways following modulation of K+ channel activity, as well as physical interaction of K+ channels with the cytoskeleton or integrins are presented. Finally, we discuss the challenges to efficient, specific, and safe targeting of K+ channels for therapeutic applications to improve epithelial repair in vivo. PMID:24196531

  4. Characterization of the gene and promoter for RTI40, a differentiation marker of type I alveolar epithelial cells.

    PubMed

    Vanderbilt, J N; Dobbs, L G

    1998-10-01

    In an effort to understand the processes that establish and maintain the differentiated state of the alveolar epithelium, we have analyzed the gene for rat type I cell 40 kD protein (RTI40), an apical integral plasma membrane protein expressed in type I but not type II alveolar epithelial cells. The RTI40 gene spans 35 kilobase pairs; it contains 6 exons and at least 6 rat Identifier repetitive elements. Three exons encode the predicted RTI40 extracellular domain and one encodes the single transmembrane spanning domain. The final exon encodes one amino acid followed by a stop codon. RTI40 gene transcription starts downstream from a TATA homology, which is immediately adjacent to putative binding sites for thyroid transcription factor 1 and Sp1. In H441 cell transfections, mutagenesis of a 5'-flanking fragment (-2496 to +104) revealed two regions that contribute to promoter activity: -1247 through -795 and -163 through -81. Heterologous promoter fusion experiments suggest that a cooperative interaction between these regions activates transcription. In transfected type II cells, deletion across the proximal region produced a 6-fold drop in promoter activity, whereas deletion across the distal region was without apparent effect. These results provide a foundation to analyze further the factors that govern alveolar epithelial cell phenotype. PMID:9761764

  5. Regulation of alveolar epithelial cell survival by the ACE-2/angiotensin 1-7/Mas axis.

    PubMed

    Uhal, Bruce D; Li, Xiaopeng; Xue, Anita; Gao, Xu; Abdul-Hafez, Amal

    2011-09-01

    Earlier work from this laboratory demonstrated that apoptosis of alveolar epithelial cells (AECs) requires autocrine generation of angiotensin (ANG) II. More recent studies showed that angiotensin converting enzyme-2 (ACE-2), which degrades ANGII to form ANG1-7, is protective but severely downregulated in human and experimental lung fibrosis. Here it was theorized that ACE-2 and its product ANG1-7 might therefore regulate AEC apoptosis. To evaluate this hypothesis, the AEC cell line MLE-12 and primary cultures of rat AECs were exposed to the profibrotic apoptosis inducers ANGII or bleomycin (Bleo). Markers of apoptosis (caspase-9 or -3 activation and nuclear fragmentation), steady-state ANGII and ANG1-7, and JNK phosphorylation were measured thereafter. In the absence of Bleo, inhibition of ACE-2 by small interfering RNA or by a competitive inhibitor (DX600 peptide) caused a reciprocal increase in autocrine ANGII and corresponding decrease in ANG1-7 in cell culture media (both P < 0.05) and, moreover, induced AEC apoptosis. At baseline (without inhibitor), ANG1-7 in culture media was 10-fold higher than ANGII (P < 0.01). Addition of purified ANGII or bleomycin-induced caspase activation, nuclear fragmentation, and JNK phosphorylation in cultured AECs. However, preincubation with ANG1-7 (0.1 μM) prevented JNK phosphorylation and apoptosis. Moreover, pretreatment with A779, a specific blocker of the ANG1-7 receptor mas, prevented ANG1-7 blockade of JNK phosphorylation, caspase activation, and nuclear fragmentation. These data demonstrate that ACE-2 regulates AEC survival by balancing the proapoptotic ANGII and its antiapoptotic degradation product ANG1-7. They also suggest that ANG1-7 inhibits AEC apoptosis through the ANG1-7 receptor mas. PMID:21665960

  6. Microfluidic shear stress-regulated surfactant secretion in alveolar epithelial type II cells in vitro.

    PubMed

    Mahto, Sanjeev Kumar; Tenenbaum-Katan, Janna; Greenblum, Ayala; Rothen-Rutishauser, Barbara; Sznitman, Josué

    2014-04-01

    We investigated the role of flow-induced shear stress on the mechanisms regulating surfactant secretion in type II alveolar epithelial cells (ATII) using microfluidic models. Following flow stimulation spanning a range of wall shear stress (WSS) magnitudes, monolayers of ATII (MLE-12 and A549) cells were examined for surfactant secretion by evaluating essential steps of the process, including relative changes in the number of fusion events of lamellar bodies (LBs) with the plasma membrane (PM) and intracellular redistribution of LBs. F-actin cytoskeleton and calcium levels were analyzed in A549 cells subjected to WSS spanning 4-20 dyn/cm(2). Results reveal an enhancement in LB fusion events with the PM in MLE-12 cells upon flow stimulation, whereas A549 cells exhibit no foreseeable changes in the monitored number of fusion events for WSS levels ranging up to a threshold of ∼8 dyn/cm(2); above this threshold, we witness instead a decrease in LB fusion events in A549 cells. However, patterns of LB redistribution suggest that WSS can potentially serve as a stimulus for A549 cells to trigger the intracellular transport of LBs toward the cell periphery. This observation is accompanied by a fragmentation of F-actin, indicating that disorganization of the F-actin cytoskeleton might act as a limiting factor for LB fusion events. Moreover, we note a rise in cytosolic calcium ([Ca(2+)]c) levels following stimulation of A549 cells with WSS magnitudes ranging near or above the experimental threshold. Overall, WSS stimulation can influence key components of molecular machinery for regulated surfactant secretion in ATII cells in vitro. PMID:24487389

  7. Regulation of Alveolar Epithelial Na+ Channels by ERK1/2 in Chlorine-Breathing Mice

    PubMed Central

    Lazrak, Ahmed; Chen, Lan; Jurkuvenaite, Asta; Doran, Stephen F.; Liu, Gang; Li, Qian; Lancaster, Jack R.

    2012-01-01

    The mechanisms by which the exposure of mice to Cl2 decreases vectorial Na+ transport and fluid clearance across their distal lung spaces have not been elucidated. We examined the biophysical, biochemical, and physiological changes of rodent lung epithelial Na+ channels (ENaCs) after exposure to Cl2, and identified the mechanisms involved. We measured amiloride-sensitive short-circuit currents (Iamil) across isolated alveolar Type II (ATII) cell monolayers and ENaC single-channel properties by patching ATII and ATI cells in situ. α-ENaC, γ-ENaC, total and phosphorylated extracellular signal-related kinase (ERK)1/2, and advanced products of lipid peroxidation in ATII cells were measured by Western blot analysis. Concentrations of reactive intermediates were assessed by electron spin resonance (ESR). Amiloride-sensitive Na+ channels with conductances of 4.5 and 18 pS were evident in ATI and ATII cells in situ of air-breathing mice. At 1 hour and 24 hours after exposure to Cl2, the open probabilities of these two channels decreased. This effect was prevented by incubating lung slices with inhibitors of ERK1/2 or of proteasomes and lysosomes. The exposure of ATII cell monolayers to Cl2 increased concentrations of reactive intermediates, leading to ERK1/2 phosphorylation and decreased Iamil and α-ENaC concentrations at 1 hour and 24 hours after exposure. The administration of antioxidants to ATII cells before and after exposure to Cl2 decreased concentrations of reactive intermediates and ERK1/2 activation, which mitigated the decrease in Iamil and ENaC concentrations. The reactive intermediates formed during and after exposure to Cl2 activated ERK1/2 in ATII cells in vitro and in vivo, leading to decreased ENaC concentrations and activity. PMID:21997487

  8. Epigenetic Regulation of Tolerance to Toll-Like Receptor Ligands in Alveolar Epithelial Cells.

    PubMed

    Neagos, Jacqueline; Standiford, Theodore J; Newstead, Michael W; Zeng, Xianying; Huang, Steven K; Ballinger, Megan N

    2015-12-01

    To protect the host against exuberant inflammation and injury responses, cells have the ability to become hyporesponsive or "tolerized" to repeated stimulation by microbial and nonmicrobial insults. The lung airspace is constantly exposed to a variety of exogenous and endogenous Toll-like receptor (TLR) ligands, yet the ability of alveolar epithelial cells (AECs) to be tolerized has yet to be examined. We hypothesize that type II AECs will develop a tolerance phenotype upon repeated TLR agonist exposure. To test this hypothesis, primary AECs isolated from the lungs of mice and a murine AEC cell line (MLE-12) were stimulated with either a vehicle control or a TLR ligand for 18 hours, washed, then restimulated with either vehicle or TLR ligand for an additional 6 hours. Tolerance was assessed by measurement of TLR ligand-stimulated chemokine production (monocyte chemoattractant protein [MCP]-1/CCL2, keratinocyte chemoattractant [KC]/CXCL1, and macrophage inflammatory protein [MIP]-2/CXCL2). Sequential treatment of primary AECs or MLE-12 cells with TLR agonists resulted in induction of either tolerance or cross-tolerance. The induction of tolerance was not due to expression of specific negative regulators of TLR signaling (interleukin-1 receptor associated kinase [IRAK]-M, Toll-interacting protein [Tollip], single Ig IL-1-related receptor [SIGIRR], or suppressor of cytokine signaling [SOCS]), inhibitory microRNAs (miRs; specifically, miR-155 and miR146a), or secretion of inhibitory or regulatory soluble mediators (prostaglandin E2, IL-10, transforming growth factor-β, or IFN-α/β). Moreover, inhibition of histone demethylation or DNA methylation did not prevent the development of tolerance. However, treatment of AECs with the histone deacetylase inhibitors trichostatin A or suberoylanilide hyrozamine resulted in reversal of the tolerance phenotype. These findings indicate a novel mechanism by which epigenetic modification regulates the induction of tolerance in AECs

  9. Oxidative damage in human epithelial alveolar cells exposed in vitro to oil fly ash transition metals.

    PubMed

    Di Pietro, Angela; Visalli, Giuseppa; Munaò, Fortunato; Baluce, Barbara; La Maestra, Sebastiano; Primerano, Patrizia; Corigliano, Francesco; De Flora, Silvio

    2009-03-01

    Among particulate matter emissions from combustion processes, oil fly ash (OFA) displays a marked oxidative and inflammogenic reactivity, due to the high content of bioavailable transition metals. In the present study, we evaluated the biological effects of an OFA water solution, composed of the transition metals Fe (57.5%), V (32.4%), and Ni (10.1%), in human epithelial alveolar cells (A549 line). The fluorimetric analysis by 2',7'-dichlorofluorescein showed a significant, dose- and time-dependent induction of intracellular reactive oxygen species (ROS) triggered by OFA metal components at subtoxic doses. The metal chelator deferoxamine and the radical scavenger dimethylsulfoxide attenuated the metal-induced generation of ROS. Confocal microscopy observations strengthened these findings and showed an intense cytoplasmic fluorescence with perinuclear thickenings in A549 cells, in the absence of morphological damage. Metal-induced generation of ROS was significantly correlated with a dose- and time-dependent DNA damage, as assessed by single cell gel electrophoresis (comet assay). Catalase was able to decrease dramatically DNA damage. Fluorimetric analyses by diphenyl-1-pyrenylphosphine showed a parallelism between generation of ROS and formation of lipid peroxides. The results obtained in the experiments evaluating the effects of individual metal solutions did not show any significant difference in DNA damage between Fe(III) and V(IV), but highlighted the higher capability of V(IV) to increase ROS in the cytoplasmic compartment. The different behavior of these two elements, confirmed by the weak Fe-induced lipid peroxidation, may be ascribed to the presence of Fe-binding proteins, such as ferritin, in the cytoplasm. Finally, Ni(II) had negligible effects on ROS production. On the whole, the results obtained in this study show the strong capability of transition metals adsorbed to OFA to cause widespread damage to biological macromolecules, and suggest potential

  10. Altered surfactant homeostasis and alveolar epithelial cell stress in amiodarone-induced lung fibrosis.

    PubMed

    Mahavadi, Poornima; Henneke, Ingrid; Ruppert, Clemens; Knudsen, Lars; Venkatesan, Shalini; Liebisch, Gerhard; Chambers, Rachel C; Ochs, Matthias; Schmitz, Gerd; Vancheri, Carlo; Seeger, Werner; Korfei, Martina; Guenther, Andreas

    2014-11-01

    Amiodarone (AD) is a highly efficient antiarrhythmic drug with potentially serious side effects. Severe pulmonary toxicity is reported in patients receiving AD even at low doses and may cause interstitial pneumonia as well as lung fibrosis. Apoptosis of alveolar epithelial type II cells (AECII) has been suggested to play an important role in this disease. In the current study, we aimed to establish a murine model of AD-induced lung fibrosis and analyze surfactant homeostasis, lysosomal, and endoplasmic reticulum (ER) stress in this model. AD/vehicle was instilled intratracheally into C57BL/6 mice, which were sacrificed on days 7, 14, 21, and 28. Extent of lung fibrosis development was assessed by trichrome staining and hydroxyproline measurement. Cytotoxicity was assessed by lactate dehydrogenase assay. Phospholipids (PLs) were analyzed by mass spectrometry. Surfactant proteins (SP) and markers for apoptosis, lysosomal, and ER stress were studied by Western blotting and immunohistochemistry. AECII morphology was evaluated by electron microscopy. Extensive lung fibrosis and AECII hyperplasia were observed in AD-treated mice already at day 7. Surfactant PL and SP accumulated in AECII over time. In parallel, induction of apoptosis, lysosomal, and ER stress was encountered in AECII of mice lungs and in MLE12 cells treated with AD. In vitro, siRNA-mediated knockdown of cathepsin D did not alter the AD-induced apoptotic response. Our data suggest that mice exposed to intratracheal AD develop severe pulmonary fibrosis, exhibit extensive surfactant alterations and cellular stress, but AD-induced AECII apoptosis is not mediated primarily via cathepsin D. PMID:25163675

  11. Linking progression of fibrotic lung remodeling and ultrastructural alterations of alveolar epithelial type II cells in the amiodarone mouse model.

    PubMed

    Birkelbach, Bastian; Lutz, Dennis; Ruppert, Clemens; Henneke, Ingrid; Lopez-Rodriguez, Elena; Günther, Andreas; Ochs, Matthias; Mahavadi, Poornima; Knudsen, Lars

    2015-07-01

    Chronic injury of alveolar epithelial type II cells (AE2 cells) represents a key event in the development of lung fibrosis in animal models and in humans, such as idiopathic pulmonary fibrosis (IPF). Intratracheal delivery of amiodarone to mice results in a profound injury and macroautophagy-dependent apoptosis of AE2 cells. Increased autophagy manifested in AE2 cells by disturbances of the intracellular surfactant. Hence, we hypothesized that ultrastructural alterations of the intracellular surfactant pool are signs of epithelial stress correlating with the severity of fibrotic remodeling. With the use of design-based stereology, the amiodarone model of pulmonary fibrosis in mice was characterized at the light and ultrastructural level during progression. Mean volume of AE2 cells, volume of lamellar bodies per AE2 cell, and mean size of lamellar bodies were correlated to structural parameters reflecting severity of fibrosis like collagen content. Within 2 wk amiodarone leads to an increase in septal wall thickness and a decrease in alveolar numbers due to irreversible alveolar collapse associated with alveolar surfactant dysfunction. Progressive hypertrophy of AE2 cells and increase in mean individual size and total volume of lamellar bodies per AE2 cell were observed. A high positive correlation of these AE2 cell-related ultrastructural changes and the deposition of collagen fibrils within septal walls were established. Qualitatively, similar alterations could be found in IPF samples with mild to moderate fibrosis. We conclude that ultrastructural alterations of AE2 cells including the surfactant system are tightly correlated with the progression of fibrotic remodeling. PMID:25957292

  12. ERK/GSK3β/Snail signaling mediates radiation-induced alveolar epithelial-to-mesenchymal transition.

    PubMed

    Nagarajan, Devipriya; Melo, Tahira; Deng, Zhiyong; Almeida, Celine; Zhao, Weiling

    2012-03-15

    Radiotherapy is one of the major treatment regimes for thoracic malignancies, but can lead to severe lung complications including pneumonitis and fibrosis. Recent studies suggest that epithelial-to-mesenchymal transition (EMT) plays an important role in tissue injury leading to organ fibrosis. To investigate whether radiation can induce EMT in lung epithelial cells and also to understand the potential mechanism(s) associated with this change, rat alveolar type II lung epithelial RLE-6TN cells were irradiated with 8 Gy of (137)Cs γ-rays. Western blot and immunofluorescence analyses revealed a time-dependent decrease in E-cadherin with a concomitant increase in α-smooth muscle actin (α-SMA) and vimentin after radiation, suggesting that the epithelial cells acquired a mesenchymal-like morphology. Protein levels and nuclear translocation of Snail, the key inducer of EMT, were significantly elevated in the irradiated cells. Radiation also induced a time-dependent inactivation of glycogen synthase kinase-3β (GSK3β), an endogenous inhibitor of Snail. A marked increase in phosphorylation of ERK1/2, but not JNK or p38, was observed in irradiated RLE-6TN cells. Silencing ERK1/2 using siRNAs and the MEK/ERK inhibitor U0126 attenuated the radiation-induced phosphorylation of GSK3β and altered the protein levels of Snail, α-SMA, and E-cadherin in RLE-6TN cells. Preincubating RLE-6TN cells with N-acetylcysteine, an antioxidant, abolished the radiation-induced phosphorylation of ERK and altered protein levels of Snail, E-cadherin, and α-SMA. These findings reveal, for the first time, that radiation-induced EMT in alveolar type II epithelial cells is mediated by the ERK/GSK3β/Snail pathway. PMID:22198183

  13. ERK/GSK3ß/Snail signaling mediates radiation-induced alveolar epithelial-to-mesenchymal transition

    PubMed Central

    Nagarajan, Devipriya; Melo, Tahira; Deng, Zhiyong; Almeida, Celine; Zhao, Weiling

    2011-01-01

    Radiotherapy is one of the major treatment regimes for thoracic malignancies, but can lead to severe lung complications including pneumonitis and fibrosis. Recent studies suggest that epithelial to mesenchymal transition (EMT) plays an important role in tissue injury leading to organ fibrosis. To investigate whether radiation can induce EMT in lung epithelial cells and also understand the potential mechanism(s) associated with this change, rat alveolar type II lung epithelial RLE-6TN cells were irradiated with 8 Gy of 137Cs γ-rays. Western blot and immunofluorescence analyses revealed a time-dependent decrease in E-cadherin with a concomitant increase in α-SMA and vimentin after radiation, suggesting that the epithelial cells acquired mesenchymal-like morphology. Protein levels and nuclear translocation of Snail, the key inducer of EMT, were significantly elevated in the irradiated cells. Radiation also induced a time-dependent inactivation of glycogen synthase kinase-3β (GSK3ß), an endogenous inhibitor of Snail. A marked increase in phosphorylation of ERK1/2, but not JNKs or p38, was observed in irradiated RLE-6TN cells. Silencing ERK1/2 using siRNAs and the MEK/ERK inhibitor U0126 attenuated the radiation-induced phosphorylation of GSK3ß and altered the protein levels of Snail, α-SMA and E-cadherin in RLE-6TN cells. Pre-incubating RLE-6TN cells with N-acetyl cysteine, an antioxidant, abolished the radiation-induced phosphorylation of ERK and altered protein levels of Snail, E-cadherin and α-SMA. These findings reveal, for the first time, that radiation-induced EMT in alveolar type II epithelial cells is mediated by the ERK/GSK3ß/Snail pathway. PMID:22198183

  14. Kidney injury molecule-1 (KIM-1) mediates renal epithelial cell repair via ERK MAPK signaling pathway

    PubMed Central

    Zhang, Zhiwei; Cai, Cindy X

    2016-01-01

    The expression of kidney injury molecule-1 (KIM-1), a very promising sensitive and specific urinary biomarker for acute renal injury, is markedly upregulated in injured and regenerating renal proximal tubular epithelial cells following ischemic or toxic insults, suggesting a possible role for this molecule in renal repair process. In the present study we report that expression of KIM-1 facilitates renal tubular epithelial cell repair by promoting cell migration and proliferation. KIM-1 expression also enhances ERK MAPK activation, and the modulatory effect of KIM-1 on cellular repair process is likely mediated via ERK MAPK signaling pathway. PMID:27084535

  15. Kidney injury molecule-1 (KIM-1) mediates renal epithelial cell repair via ERK MAPK signaling pathway.

    PubMed

    Zhang, Zhiwei; Cai, Cindy X

    2016-05-01

    The expression of kidney injury molecule-1 (KIM-1), a very promising sensitive and specific urinary biomarker for acute renal injury, is markedly upregulated in injured and regenerating renal proximal tubular epithelial cells following ischemic or toxic insults, suggesting a possible role for this molecule in renal repair process. In the present study, we report that expression of KIM-1 facilitates renal tubular epithelial cell repair by promoting cell migration and proliferation. KIM-1 expression also enhances ERK MAPK activation, and the modulatory effect of KIM-1 on cellular repair process is likely mediated via ERK MAPK signaling pathway. PMID:27084535

  16. Effects of particle exposure and particle-elicited inflammatory cells on mutation in rat alveolar epithelial cells.

    PubMed

    Driscoll, K E; Deyo, L C; Carter, J M; Howard, B W; Hassenbein, D G; Bertram, T A

    1997-02-01

    To investigate mechanisms underlying development of lung adenomas and carcinomas in rats exposed to poorly soluble particles the relationships between particle exposure, inflammation and mutagenesis in rat alveolar type II cells were characterized. Rats were exposed to saline or saline suspensions of 10 and 100 mg/kg of alpha-quartz, carbon black or titanium dioxide by intratracheal instillation. Fifteen months after exposure, bronchoalveolar lavage (BAL) cells were characterized as to number and type and lung histopathology performed. The alveolar type II cells were isolated and cultured in 6 thioguanine (6TG) containing media to select for mutation in the hprt gene. The potential contribution of lung inflammatory cells to in vivo mutagenic responses, were evaluated by co-culturing BAL cells with the rat alveolar epithelial cell line, RLE-6TN for 24 h and the RLE-6TN cells selected for 6TG resistance. Neutrophilic inflammation was detected in all rats exposed to 10 and 100 mg/kg of alpha-quartz and carbon black and 100 mg/kg titanium dioxide; epithelial hyperplasia was observed in rats exposed to 10 and 100 mg/kg of alpha-quartz and 100 mg/kg carbon black. Hprt mutation frequency was increased in alveolar type II cells from rats exposed to 10 and 100 mg/kg of alpha-quartz, 100 mg/kg carbon black and 100 mg/kg titanium dioxide. In vitro exposure of RLE-6TN cells to BAL cells from rats treated with 10 and 100 mg/kg of alpha-quartz or 100 mg/kg carbon black increased hprt mutant frequency. Both macrophage and neutrophil enriched BAL cell populations were mutagenic to RLE-6TN cells, however, the mutagenic activity appeared greatest for neutrophils. Addition of catalase to BAL cell:RLE-6TN co-cultures inhibited the increase in hprt mutation frequency. These studies demonstrate exposure of rats to doses of particles producing significant neutrophilic inflammation is associated with increased mutation in rat alveolar type II cells. The ability of particle

  17. Clathrin-mediated endocytosis of FITC-albumin in alveolar type II epithelial cell line RLE-6TN.

    PubMed

    Yumoto, Ryoko; Nishikawa, Hiromi; Okamoto, Miho; Katayama, Hirokazu; Nagai, Junya; Takano, Mikihisa

    2006-05-01

    We examined mechanisms of FITC-albumin uptake by alveolar type II epithelial cells using cultured RLE-6TN cells. Alkaline phosphatase activity and the expression of cytokeratin 19 mRNA, which are characteristic features of alveolar type II epithelial cells, were detected in RLE-6TN cells. The uptake of FITC-albumin by the cells was time and temperature dependent and showed the saturation kinetics of high- and low-affinity transport systems. FITC-albumin uptake was inhibited by native albumin, by chemically modified albumin, and by metabolic inhibitors and bafilomycin A(1), an inhibitor of vacuolar H(+)-ATPase. Confocal laser scanning microscopic analysis after FITC-albumin uptake showed punctate localization of fluorescence in the cells, which was partly localized in lysosomes. FITC-albumin taken up by the cells gradually degraded over time, as shown by fluoroimage analyzer after SDS-PAGE. The uptake of FITC-albumin by RLE-6TN cells was not inhibited by nystatin, indomethacin, or methyl-beta-cyclodextrin (inhibitors of caveolae-mediated endocytosis) but was inhibited by phenylarsine oxide and chlorpromazine (inhibitors of clathrin-mediated endocytosis) in a concentration-dependent manner. Uptake was also inhibited by potassium depletion and hypertonicity, conditions known to inhibit clathrin-mediated endocytosis. These results indicate that the uptake of FITC-albumin in cultured alveolar type II epithelial cells, RLE-6TN, is mediated by clathrin-mediated but not by caveolae-mediated endocytosis, and intracellular FITC-albumin is gradually degraded in lysosomes. Possible receptors involved in this endocytic system are discussed. PMID:16361359

  18. Effect of laser phototherapy on human alveolar bone repair: micro tomographic and histomorphometrical analysis

    NASA Astrophysics Data System (ADS)

    Romão, Marcia M. A.; Marques, Márcia M.; Cortes, Arthur R. G.; Horliana, Anna C. R. T.; Moreira, Maria S.; Lascala, Cesar A.

    2015-06-01

    The immediate dental implant placement in the molars region is critical, because of the high amount of bone loss and the discrepancy between the alveolar crest thickness and the dental implant platform. Laser phototherapy (LPT) improves bone repair thus could accelerate the implant placement. Twenty patients were selected for the study. Ten patients were submitted to LPT with GaAlAs diode laser (808nm) during molar extraction, immediately after, 24h, 48h, 72h, 96h and 7 days. The irradiations were applied in contact and punctual mode (100mW, 0.04cm2, 0.75J/cm2, 30s per point, 3J per point). The control group (n=10) received the same treatment; however with the power of the laser off. Forty days later samples of the tissue formed inside the sockets were obtained for further microtomography (microCTs) and histomorphometry analyses. Data were compared by the Student t test, whereas those from the different microCT parameters were compared by the Pearson correlation test (p<0.05). The relative bone volume, as well as area was significantly higher (p<0.001) in the lased than the control group. In the control group there were negative correlations between number and thickness, and between number and separation of trabecula (p<0.01). Between thickness and separation of trabecula the correlation was positive (p<0.01). The laser group showed significant negative correlation between the number and the thickness of trabecula (p<0.01). LPT accelerated bone repair. By the Pearson correlation test it was possible to infer that the lased group presented a more homogeneous trabecular configuration, which would allow earlier dental implant placement.

  19. Construction of p66Shc gene interfering lentivirus vectors and its effects on alveolar epithelial cells apoptosis induced by hyperoxia

    PubMed Central

    Zhang, Chan; Dong, Wen-Bin; Zhao, Shuai; Li, Qing-Ping; Kang, Lan; Lei, Xiao-Ping; Guo, Lin; Zhai, Xue-Song

    2016-01-01

    Background The aim of this study is to observe the inhibitive effects of p66Shc gene interfering lentivirus vectors on the expression of p66Shc, and to explore its effects on alveolar epithelial cells apoptosis induced by hyperoxia. Methods The gene sequences were cloned into the pLenR-GPH-shRNA lentiviral vector, which was selected by Genebank searches. The pLenR-GPH-shRNA and lentiviral vector packaging plasmid mix were cotransfected into 293T cells to package lentiviral particles. Culture virus supernatant was harvested, and then the virus titer was determined by serial dilution assay. A549 cells were transduced with the constructed lentiviral vectors, and real-time polymerase chain reaction (RT-PCR) and Western blot were used to evaluate p66Shc expression. This study is divided into a control group, a hyperoxia group, an A549-p66ShcshRNA hyperoxia group, and a negative lentivirus group. Cell apoptosis was detected by flow cytometry after 24 hours; the expression of X-linked inhibitor of apoptosis protein (XIAP) and caspase-9 were detected by immunohistochemistry assay. The production of reactive oxygen species and cellular mitochondria membrane potential (ΔΨm) were determined by fluorescence microscopy. Results We successfully established the p66Shc gene interfering lentivirus vectors, A549-p66ShcshRNA. The A549-p66ShcshRNA was transfected into alveolar epithelial cells, and the inhibitive effects on the expression of p66Shc were observed. Both RT-PCR and Western blot demonstrated downregulation of p66Shc expression in A549 cells. In the A549-p66ShcshRNA hyperoxia group, we found dampened oxidative stress. A549-p66ShcshRNA can cause p66Shc gene silencing, reduce mitochondrial reactive oxygen species generation, reduce membrane potential decrease, reduce the apoptosis of A549 cells, and reduce alveolar epithelial cell injury, while the lentiviral empty vector group had no such changes. Conclusion p66Shc gene interfering lentivirus vector can affect the

  20. Macrophages programmed by apoptotic cells inhibit epithelial-mesenchymal transition in lung alveolar epithelial cells via PGE2, PGD2, and HGF.

    PubMed

    Yoon, Young-So; Lee, Ye-Ji; Choi, Youn-Hee; Park, Young Mi; Kang, Jihee Lee

    2016-01-01

    Apoptotic cell clearance results in the release of growth factors and the action of signaling molecules involved in tissue homeostasis maintenance. Here, we investigated whether and how macrophages programmed by apoptotic cells inhibit the TGF-β1-induced Epithelial-mesenchymal transition (EMT) process in lung alveolar epithelial cells. Treatment with conditioned medium derived from macrophages exposed to apoptotic cells, but not viable or necrotic cells, inhibited TGF-β1-induced EMT, including loss of E-cadherin, synthesis of N-cadherin and α-smooth muscle actin, and induction of EMT-activating transcription factors, such as Snail1/2, Zeb1/2, and Twist1. Exposure of macrophages to cyclooxygenase (COX-2) inhibitors (NS-398 and COX-2 siRNA) or RhoA/Rho kinase inhibitors (Y-27632 and RhoA siRNA) and LA-4 cells to antagonists of prostaglandin E2 (PGE2) receptor (EP4 [AH-23848]), PGD2 receptors (DP1 [BW-A868C] and DP2 [BAY-u3405]), or the hepatocyte growth factor (HGF) receptor c-Met (PHA-665752), reversed EMT inhibition by the conditioned medium. Additionally, we found that apoptotic cell instillation inhibited bleomycin-mediated EMT in primary mouse alveolar type II epithelial cells in vivo. Our data suggest a new model for epithelial cell homeostasis, by which the anti-EMT programming of macrophages by apoptotic cells may control the progressive fibrotic reaction via the production of potent paracrine EMT inhibitors. PMID:26875548

  1. Macrophages programmed by apoptotic cells inhibit epithelial-mesenchymal transition in lung alveolar epithelial cells via PGE2, PGD2, and HGF

    PubMed Central

    Yoon, Young-So; Lee, Ye-Ji; Choi, Youn-Hee; Park, Young Mi; Kang, Jihee Lee

    2016-01-01

    Apoptotic cell clearance results in the release of growth factors and the action of signaling molecules involved in tissue homeostasis maintenance. Here, we investigated whether and how macrophages programmed by apoptotic cells inhibit the TGF-β1-induced Epithelial-mesenchymal transition (EMT) process in lung alveolar epithelial cells. Treatment with conditioned medium derived from macrophages exposed to apoptotic cells, but not viable or necrotic cells, inhibited TGF-β1-induced EMT, including loss of E-cadherin, synthesis of N-cadherin and α-smooth muscle actin, and induction of EMT-activating transcription factors, such as Snail1/2, Zeb1/2, and Twist1. Exposure of macrophages to cyclooxygenase (COX-2) inhibitors (NS-398 and COX-2 siRNA) or RhoA/Rho kinase inhibitors (Y-27632 and RhoA siRNA) and LA-4 cells to antagonists of prostaglandin E2 (PGE2) receptor (EP4 [AH-23848]), PGD2 receptors (DP1 [BW-A868C] and DP2 [BAY-u3405]), or the hepatocyte growth factor (HGF) receptor c-Met (PHA-665752), reversed EMT inhibition by the conditioned medium. Additionally, we found that apoptotic cell instillation inhibited bleomycin-mediated EMT in primary mouse alveolar type II epithelial cells in vivo. Our data suggest a new model for epithelial cell homeostasis, by which the anti-EMT programming of macrophages by apoptotic cells may control the progressive fibrotic reaction via the production of potent paracrine EMT inhibitors. PMID:26875548

  2. TREK-1 Regulates Cytokine Secretion from Cultured Human Alveolar Epithelial Cells Independently of Cytoskeletal Rearrangements

    PubMed Central

    Schwingshackl, Andreas; Roan, Esra; Teng, Bin; Waters, Christopher M.

    2015-01-01

    Background TREK-1 deficient alveolar epithelial cells (AECs) secrete less IL-6, more MCP-1, and contain less F-actin. Whether these alterations in cytokine secretion and F-actin content are related remains unknown. We now hypothesized that cytokine secretion from TREK-1-deficient AECs was regulated by cytoskeletal rearrangements. Methods We determined F-actin and α-tubulin contents of control, TREK-1-deficient and TREK-1-overexpressing human A549 cells by confocal microscopy and western blotting, and measured IL-6 and MCP-1 levels using real-time PCR and ELISA. Results Cytochalasin D decreased the F-actin content of control cells. Jasplakinolide increased the F-actin content of TREK-1 deficient cells, similar to the effect of TREK-1 overexpression in control cells. Treatment of control and TREK-1 deficient cells with TNF-α, a strong stimulus for IL-6 and MCP-1 secretion, had no effect on F-actin structures. The combination of TNF-α+cytochalasin D or TNF-α+jasplakinolide had no additional effect on the F-actin content or architecture when compared to cytochalasin D or jasplakinolide alone. Although TREK-1 deficient AECs contained less F-actin at baseline, quantified biochemically, they contained more α-tubulin. Exposure to nocodazole disrupted α-tubulin filaments in control and TREK-1 deficient cells, but left the overall amount of α-tubulin unchanged. Although TNF-α had no effect on the F-actin or α-tubulin contents, it increased IL-6 and MCP-1 production and secretion from control and TREK-1 deficient cells. IL-6 and MCP-1 secretions from control and TREK-1 deficient cells after TNF-α+jasplakinolide or TNF-α+nocodazole treatment was similar to the effect of TNF-α alone. Interestingly, cytochalasin D decreased TNF-α-induced IL-6 but not MCP-1 secretion from control but not TREK-1 deficient cells. Conclusion Although cytochalasin D, jasplakinolide and nocodazole altered the F-actin and α-tubulin structures of control and TREK-1 deficient AEC, the

  3. Troglitazone attenuates TGF-β1-induced EMT in alveolar epithelial cells via a PPARγ-independent mechanism.

    PubMed

    Zhou, Beiyun; Buckley, Stephen T; Patel, Vipul; Liu, Yixin; Luo, Jiao; Krishnaveni, Manda Sai; Ivan, Mihaela; DeMaio, Lucas; Kim, Kwang-Jin; Ehrhardt, Carsten; Crandall, Edward D; Borok, Zea

    2012-01-01

    Peroxisome proliferator activated receptor γ (PPARγ) agonists are effective antifibrotic agents in a number of tissues. Effects of these agents on epithelial-mesenchymal transition (EMT) of primary alveolar epithelial cells (AEC) and potential mechanisms underlying effects on EMT have not been well delineated. We examined effects of troglitazone, a synthetic PPARγ agonist, on transforming growth factor (TGF)-β1-induced EMT in primary rat AEC and an alveolar epithelial type II (AT2) cell line (RLE-6TN). TGF-β1 (2.5 ng/mL) induced EMT in both cell types, as evidenced by acquisition of spindle-like morphology, increased expression of the mesenchymal marker α-smooth muscle actin (α-SMA) and downregulation of the tight junctional protein zonula occludens-1 (ZO-1). Concurrent treatment with troglitazone (or rosiglitazone), ameliorated effects of TGF-β1. Furthermore, following stimulation with TGF-β1 for 6 days, troglitazone reversed EMT-related morphological changes and restored both epithelial and mesenchymal markers to control levels. Treatment with GW9662 (an irreversible PPARγ antagonist), or overexpression of a PPARγ dominant negative construct, failed to inhibit these effects of troglitazone in AEC. Troglitazone not only attenuated TGF-β1-induced phosphorylation of Akt and glycogen synthase kinase (GSK)-3β, but also inhibited nuclear translocation of β-catenin, phosphorylation of Smad2 and Smad3 and upregulation of the EMT-associated transcription factor SNAI1. These results demonstrate inhibitory actions of troglitazone on TGF-β1-induced EMT in AEC via a PPARγ-independent mechanism likely through inhibition of β-catenin-dependent signaling downstream of TGF-β1, supporting a role for interactions between TGF-β and Wnt/β-catenin signaling pathways in EMT. PMID:22745681

  4. Troglitazone Attenuates TGF-β1-Induced EMT in Alveolar Epithelial Cells via a PPARγ-Independent Mechanism

    PubMed Central

    Patel, Vipul; Liu, Yixin; Luo, Jiao; Krishnaveni, Manda Sai; Ivan, Mihaela; DeMaio, Lucas; Kim, Kwang-Jin; Ehrhardt, Carsten; Crandall, Edward D.; Borok, Zea

    2012-01-01

    Peroxisome proliferator activated receptor γ (PPARγ) agonists are effective antifibrotic agents in a number of tissues. Effects of these agents on epithelial-mesenchymal transition (EMT) of primary alveolar epithelial cells (AEC) and potential mechanisms underlying effects on EMT have not been well delineated. We examined effects of troglitazone, a synthetic PPARγ agonist, on transforming growth factor (TGF)-β1-induced EMT in primary rat AEC and an alveolar epithelial type II (AT2) cell line (RLE-6TN). TGF-β1 (2.5 ng/mL) induced EMT in both cell types, as evidenced by acquisition of spindle-like morphology, increased expression of the mesenchymal marker α-smooth muscle actin (α-SMA) and downregulation of the tight junctional protein zonula occludens-1 (ZO-1). Concurrent treatment with troglitazone (or rosiglitazone), ameliorated effects of TGF-β1. Furthermore, following stimulation with TGF-β1 for 6 days, troglitazone reversed EMT-related morphological changes and restored both epithelial and mesenchymal markers to control levels. Treatment with GW9662 (an irreversible PPARγ antagonist), or overexpression of a PPARγ dominant negative construct, failed to inhibit these effects of troglitazone in AEC. Troglitazone not only attenuated TGF-β1-induced phosphorylation of Akt and glycogen synthase kinase (GSK)-3β, but also inhibited nuclear translocation of β-catenin, phosphorylation of Smad2 and Smad3 and upregulation of the EMT-associated transcription factor SNAI1. These results demonstrate inhibitory actions of troglitazone on TGF-β1-induced EMT in AEC via a PPARγ-independent mechanism likely through inhibition of β-catenin-dependent signaling downstream of TGF-β1, supporting a role for interactions between TGF-β and Wnt/β-catenin signaling pathways in EMT. PMID:22745681

  5. DNA repair and mutagen sensitivity of epithelial cells and lymphocytes in oropharyngeal cancer

    PubMed Central

    REITER, MAXIMILIAN; BAUMEISTER, PHILIPP; JAISER, SONJA; REISS, ANDREAS; SCHWENK-ZIEGER, SABINA; KLEINSASSER, NORBERT; HARRÉUS, ULRICH

    2012-01-01

    Tobacco-associated nitrosamines are known carcinogens causing DNA damage in epithelial cells of the head and neck. A matched case-control study was performed to evaluate the sensitivity of patients with squamous cell cancer (SCC) of the oropharynx, and controls to tobacco-associated nitrosamines. Quantitative DNA repair was evaluated following a period of 15 and 30 min. Fresh biopsies from 100 male donors of macroscopically healthy oropharyngeal cells and lymphocytes (50 SCC patients and 50 controls) were incubated with N-nitrosodiethylamine (NDEA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) or N-nitrosonornicotine (NNN). DNA damage in epithelial cells and lymphocytes was assessed using the comet assay. Following incubation with NDEA, cells underwent a period of DNA repair. All of the nitrosamines caused equivalent genotoxic damage in mucosal cells and lymphocytes of the two groups. Lymphocyte DNA repair capacity in the control group (26.8 and 37.1% after 15 and 30 min) was comparable to the tumor group (23.6 and 40.6%). However, epithelial cell DNA repair capacity of carcinoma patients was significantly reduced to 17.1% (15 min) and 23% (30 min) compared to the DNA repair of the control group (36.2%, 15 min and 46.0%, 30 min). Mutagen sensitivity was comparable in patients and controls. Thus, reduced epithelial cell DNA repair capacity of tumor patients is a possible endogenous risk factor for the development of head and neck squamous cell cancer. PMID:22740863

  6. Alveolar Epithelial Cells Secrete Chemokines in Response to IL-1β and Lipopolysaccharide but Not to Ozone

    PubMed Central

    Manzer, Rizwan; Wang, Jieru; Nishina, Kahoru; McConville, Glen; Mason, Robert J.

    2006-01-01

    Ozone exposure produces acute inflammation and neutrophil influx in the distal lung. Alveolar epithelial cells cover a large surface area, secrete chemokines, and may initiate or modify the inflammatory response. The effect of ozone on chemokine production by these cells has not been defined. Isolated rat type II cells were cultured in different conditions to express the morphologic appearance and biochemical markers for the type I and the type II cell phenotypes. These cells were exposed to ozone at an air/liquid interface. The type I–like cells were more susceptible to injury than the type II cells and showed signs of injury at exposure levels of 100 ppb ozone for 60 min. Both phenotypes showed evidence of lipid peroxidation after ozone exposure as measured by 8-isoprostane production, but neither phenotype secreted increased amounts of MIP-2 (CXCL3), CINC-1 (CXCL1), or MCP-1 (CCL2) in response to ozone. Both cell phenotypes secreted MIP-2 and MCP-1 in response to IL-1β or lipopolysaccharide, but there was no priming or synergy with ozone. It is likely that the inflammatory response to ozone in the alveolar compartment is not due to the direct effect of ozone on epithelial cells. PMID:16239643

  7. M2 polarized macrophages induced by CSE promote proliferation, migration, and invasion of alveolar basal epithelial cells.

    PubMed

    Fu, Xiao; Shi, Hengfei; Qi, Yue; Zhang, Weiyun; Dong, Ping

    2015-09-01

    Cigarette smoking plays an important role in the genesis of lung cancer, and tumor-associated macrophages (TAMs) are believed to accelerate the process. We therefore sought to clarify the relationship between cigarette smoking, TAMs and tumorigenesis. We treated macrophages (THP-1) with cigarette smoke extract (CSE) and found that the mRNA levels of IL-6, IL-10, IL-12 and TNF-α decreased, while TGF-β mRNA levels increased. CSE significantly inhibited the phagocytic ability of macrophages, as assessed by flow cytometric analysis of FITC-dextran internalization. JAK2/STAT3 was significantly activated by CSE, as determined by Western blot analysis. When the scavenger receptor CD163, a specific marker of M2 macrophages, was analyzed by flow cytometry, its expression was significantly increased. After inducing M2 polarization of THP-1 cells, we co-cultured macrophages and alveolar basal epithelial cells (A549). The proliferation of A549 cells was detected by the MTT assay and cell cycle analysis, while their migration and invasion were detected by scratch wound assay and transwell assay. The results showed that the proliferation, migration and invasion of A549 cells were significantly promoted by M2 macrophages but were slightly inhibited by CSE. In conclusion, we demonstrated that macrophage M2 polarization induced by CSE promotes proliferation, migration, and invasion of alveolar basal epithelial cells. PMID:26253658

  8. Induction of epithelial-mesenchymal transition in alveolar epithelial cells by transforming growth factor-beta1: potential role in idiopathic pulmonary fibrosis.

    PubMed

    Willis, Brigham C; Liebler, Janice M; Luby-Phelps, Katherine; Nicholson, Andrew G; Crandall, Edward D; du Bois, Roland M; Borok, Zea

    2005-05-01

    The hallmark of idiopathic pulmonary fibrosis (IPF) is the myofibroblast, the cellular origin of which in the lung is unknown. We hypothesized that alveolar epithelial cells (AECs) may serve as a source of myofibroblasts through epithelial-mesenchymal transition (EMT). Effects of chronic exposure to transforming growth factor (TGF)-beta1 on the phenotype of isolated rat AECs in primary culture and a rat type II cell line (RLE-6TN) were evaluated. Additionally, tissue samples from patients with IPF were evaluated for cells co-expressing epithelial (thyroid transcription factor (TTF)-1 and pro-surfactant protein-B (pro-SP-B), and mesenchymal (alpha-smooth muscle actin (alpha-SMA)) markers. RLE-6TN cells exposed to TGF-beta1 for 6 days demonstrated increased expression of mesenchymal cell markers and a fibroblast-like morphology, an effect augmented by tumor necrosis factor-alpha (TNF-alpha). Exposure of rat AECs to TGF-beta1 (100 pmol/L) resulted in increased expression of alpha-SMA, type I collagen, vimentin, and desmin, with concurrent transition to a fibroblast-like morphology and decreased expression of TTF-1, aquaporin-5 (AQP5), zonula occludens-1 (ZO-1), and cytokeratins. Cells co-expressing epithelial markers and alpha-SMA were abundant in lung tissue from IPF patients. These results suggest that AECs undergo EMT when chronically exposed to TGF-beta1, raising the possibility that epithelial cells may serve as a novel source of myofibroblasts in IPF. PMID:15855634

  9. Multiple cis Regulatory Elements Control RANTES Promoter Activity in Alveolar Epithelial Cells Infected with Respiratory Syncytial Virus

    PubMed Central

    Casola, Antonella; Garofalo, Roberto P.; Haeberle, Helene; Elliott, Todd F.; Lin, Rongtuan; Jamaluddin, Mohammad; Brasier, Allan R.

    2001-01-01

    Respiratory syncytial virus (RSV) produces intense pulmonary inflammation, in part through its ability to induce chemokine synthesis in infected airway epithelial cells. RANTES (regulated upon activation, normally T-cell expressed and presumably secreted) is a CC chemokine which recruits and activates monocytes, lymphocytes, and eosinophils, all cell types present in the lung inflammatory infiltrate induced by RSV infection. In this study, we analyzed the mechanism of RSV-induced RANTES promoter activation in human type II alveolar epithelial cells (A549 cells). Promoter deletion and mutagenesis experiments indicate that RSV requires the presence of five different cis regulatory elements, located in the promoter fragment spanning from −220 to +55 nucleotides, corresponding to NF-κB, C/EBP, Jun/CREB/ATF, and interferon regulatory factor (IRF) binding sites. Although site mutations of the NF-κB, C/EBP, and CREB/AP-1 like sites reduce RSV-induced RANTES gene transcription to 50% or less, only mutations affecting IRF binding completely abolish RANTES inducibility. Supershift and microaffinity isolation assays were used to identify the different transcription factor family members whose DNA binding activity was RSV inducible. Expression of dominant negative mutants of these transcription factors further established their central role in virus-induced RANTES promoter activation. Our finding that the presence of multiple cis regulatory elements is required for full activation of the RANTES promoter in RSV-infected alveolar epithelial cells supports the enhanceosome model for RANTES gene transcription, which is absolutely dependent on binding of IRF transcription factors. The identification of regulatory mechanisms of RANTES gene expression is fundamental for rational design of inhibitors of RSV-induced lung inflammation. PMID:11413310

  10. GM-CSF provides autocrine protection for murine alveolar epithelial cells from oxidant-induced mitochondrial injury.

    PubMed

    Sturrock, Anne; Seedahmed, Elfateh; Mir-Kasimov, Mustafa; Boltax, Jonathan; McManus, Michael L; Paine, Robert

    2012-02-01

    Exposure of mice to hyperoxia induces alveolar epithelial cell (AEC) injury, acute lung injury and death. Overexpression of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the lung protects against these effects, although the mechanisms are not yet clear. Hyperoxia induces cellular injury via effects on mitochondrial integrity, associated with induction of proapoptotic members of the Bcl-2 family. We hypothesized that GM-CSF protects AEC through effects on mitochondrial integrity. MLE-12 cells (a murine type II cell line) and primary murine type II AEC were subjected to oxidative stress by exposure to 80% oxygen and by exposure to H(2)O(2). Exposure to H(2)O(2) induced cytochrome c release and decreased mitochondrial reductase activity in MLE-12 cells. Incubation with GM-CSF significantly attenuated these effects. Protection induced by GM-CSF was associated with Akt activation. GM-CSF treatment also resulted in increased expression of the antiapoptotic Bcl-2 family member, Mcl-1. Primary murine AEC were significantly more tolerant of oxidative stress than MLE-12 cells. In contrast to MLE-12 cells, primary AEC expressed significant GM-CSF at baseline and demonstrated constitutive activation of Akt and increased baseline expression of Mcl-1. Treatment with exogenous GM-CSF further increased Akt activation and Mcl-1 expression in primary AEC. Conversely, suppression of AEC GM-CSF expression by use of GM-CSF-specific small interfering RNA resulted in decreased tolerance of oxidative stress, Furthermore, silencing of Mcl-1 prevented GM-CSF-induced protection. We conclude that GM-CSF protects alveolar epithelial cells against oxidative stress-induced mitochondrial injury via the Akt pathway and its downstream components, including Mcl-1. Epithelial cell-derived GM-CSF may contribute to intrinsic defense mechanisms limiting lung injury. PMID:22140071

  11. Elastolytic activity and alveolar epithelial type-1 cell damage after chronic LPS inhalation: Effects of dexamethasone and rolipram

    SciTech Connect

    Johnson, Frederick J. . E-mail: JohnsonFJ@Cardiff.ac.uk; Reynolds, Lucy J.; Toward, Toby J.

    2005-09-15

    This study investigated whether a correlation between leukocyte-derived elastolytic activity, alveolar epithelial type-1 cell damage, and leukocyte infiltration of the airways existed in guinea-pigs chronically exposed to inhaled lipopolysaccharide (LPS). The airway pathology of this model, notably the neutrophilia, resembles chronic obstructive pulmonary disease (COPD). The effect of the corticosteroid, dexamethasone, or the phosphodiesterase-4 (PDE4)-inhibitor, rolipram, on these features was studied. Conscious guinea-pigs were exposed for 1 h to single or repeated (nine) doses of LPS (30 {mu}g ml{sup -1}). Dexamethasone (20 mg kg{sup -1}, ip) or rolipram (1 mg kg{sup -1}, ip) was administered 24 and 0.5 h before the first exposure and daily thereafter. Bronchoalveolar lavage fluid (BALF) was removed and elastolytic activity determined as the elastase-like release of Congo Red from impregnated elastin. The presence of the specific epithelial cell type-1 protein (40-42 kDa) RT1{sub 40} in BALF was identified by Western blotting using a rat monoclonal antibody and semi-quantified by dot-blot analysis. The antibody was found to identify guinea-pig RT1{sub 40}. BALF inflammatory cells, particularly neutrophils and macrophages, and elastolytic activity were increased in chronic LPS-exposed guinea-pigs, the latter by 90%. Chronic LPS exposure also increased (10.5-fold) RT1{sub 40} levels, indicating significant alveolar epithelial type-1 cell damage. Dexamethasone or rolipram treatment reduced the influx of inflammatory cells, the elastolytic activity (by 40% and 38%, respectively), and RT1{sub 40} levels (by 50% and 57%, respectively). In conclusion, chronic LPS-exposed guinea-pigs, like COPD, exhibit elastolytic lung damage. This was prevented by a PDE4 inhibitor and supports their development for suppressing this leukocyte-mediated pathology.

  12. Role of matrix metalloproteinases in radiation-induced lung injury in alveolar epithelial cells of Bama minipigs

    PubMed Central

    YUE, HAIYING; HU, KAI; LIU, WENQI; JIANG, JIE; CHEN, YUHUA; WANG, RENSHENG

    2015-01-01

    Radiation-induced lung injury (RILI) is a common complication associated with thoracic radiotherapy. The aim of the present study was to investigate the effects of a single 15-Gy dose of right-thoracic lung irradiation on the expression levels of matrix metalloproteinases (MMPs) and other proteins in the alveolar epithelial type II (AE2) cells of Bama minipigs. All minipigs received either right-thoracic irradiation or sham irradiation under anesthesia, and were sacrificed at 4, 8, 12 or 24 weeks after irradiation. Collagen deposition was measured using Massons trichrome staining. Surfactant protein A (SP-A), transforming growth factor β1 (TGFβ1), MMP2, MMP9, vimentin and E-cadherin protein expression levels were evaluated using western blot analysis, and the MMP2 and MMP9 gelatinase activities were tested using gelatin zymography. SP-A and α-smooth muscle actin (α-SMA) co-localization was visualized using double immunofluorescence staining. At each time-point following irradiation, a significant increase in TGFβ1, α-SMA, MMP2, MMP9 and vimentin protein expression levels and MMP2 and MMP9 gelatinase activity were observed in the irradiated lungs compared with the sham-irradiated controls. By contrast, SP-A and E-cadherin protein expression levels decreased in a time-dependent manner post-irradiation. SP-A and α-SMA co-localization was observed in irradiated alveolar epithelial cells. These data demonstrate that E-cadherin, SP-A, MMP2 and MMP9 may function as sensitive predictors of RILI. Epithelial-mesenchymal transition (EMT) occurs in the irradiated lungs of Bama minipigs, and MMP2 and MMP9 may contribute to EMT in AE2 cells by regulating TGFβ1. Therefore, EMT may serve a crucial function in the development of RILI. PMID:26622503

  13. Hypotonic shock modulates Na(+) current via a Cl(-) and Ca(2+)/calmodulin dependent mechanism in alveolar epithelial cells.

    PubMed

    Dagenais, André; Tessier, Marie-Claude; Tatur, Sabina; Brochiero, Emmanuelle; Grygorczyk, Ryszard; Berthiaume, Yves

    2013-01-01

    Alveolar epithelial cells are involved in Na(+) absorption via the epithelial Na(+) channel (ENaC), an important process for maintaining an appropriate volume of liquid lining the respiratory epithelium and for lung oedema clearance. Here, we investigated how a 20% hypotonic shock modulates the ionic current in these cells. Polarized alveolar epithelial cells isolated from rat lungs were cultured on permeant filters and their electrophysiological properties recorded. A 20% bilateral hypotonic shock induced an immediate, but transient 52% rise in total transepithelial current and a 67% increase in the amiloride-sensitive current mediated by ENaC. Amiloride pre-treatment decreased the current rise after hypotonic shock, showing that ENaC current is involved in this response. Since Cl(-) transport is modulated by hypotonic shock, its contribution to the basal and hypotonic-induced transepithelial current was also assessed. Apical NPPB, a broad Cl(-) channel inhibitor and basolateral DIOA a potassium chloride co-transporter (KCC) inhibitor reduced the total and ENaC currents, showing that transcellular Cl(-) transport plays a major role in that process. During hypotonic shock, a basolateral Cl(-) influx, partly inhibited by NPPB is essential for the hypotonic-induced current rise. Hypotonic shock promoted apical ATP secretion and increased intracellular Ca(2+). While apyrase, an ATP scavenger, did not inhibit the hypotonic shock current response, W7 a calmodulin antagonist completely prevented the hypotonic current rise. These results indicate that a basolateral Cl(-) influx as well as Ca(2+)/calmodulin, but not ATP, are involved in the acute transepithelial current rise elicited by hypotonic shock. PMID:24019969

  14. XB130 promotes bronchioalveolar stem cell and Club cell proliferation in airway epithelial repair and regeneration

    PubMed Central

    Toba, Hiroaki; Wang, Yingchun; Bai, Xiaohui; Zamel, Ricardo; Cho, Hae-Ra; Liu, Hongmei; Lira, Alonso; Keshavjee, Shaf; Liu, Mingyao

    2015-01-01

    Proliferation of bronchioalveolar stem cells (BASCs) is essential for epithelial repair. XB130 is a novel adaptor protein involved in the regulation of epithelial cell survival, proliferation and migration through the PI3K/Akt pathway. To determine the role of XB130 in airway epithelial injury repair and regeneration, a naphthalene-induced airway epithelial injury model was used with XB130 knockout (KO) mice and their wild type (WT) littermates. In XB130 KO mice, at days 7 and 14, small airway epithelium repair was significantly delayed with fewer number of Club cells (previously called Clara cells). CCSP (Club cell secreted protein) mRNA expression was also significantly lower in KO mice at day 7. At day 5, there were significantly fewer proliferative epithelial cells in the KO group, and the number of BASCs significantly increased in WT mice but not in KO mice. At day 7, phosphorylation of Akt, GSK-3β, and the p85α subunit of PI3K was observed in airway epithelial cells in WT mice, but to a much lesser extent in KO mice. Microarray data also suggest that PI3K/Akt-related signals were regulated differently in KO and WT mice. An inhibitory mechanism for cell proliferation and cell cycle progression was suggested in KO mice. XB130 is involved in bronchioalveolar stem cell and Club cell proliferation, likely through the PI3K/Akt/GSK-3β pathway. PMID:26360608

  15. Hypoxia increases transepithelial electrical conductance and reduces occludin at the plasma membrane in alveolar epithelial cells via PKC-ζ and PP2A pathway.

    PubMed

    Caraballo, Juan Carlos; Yshii, Cecilia; Butti, Maria L; Westphal, Whitney; Borcherding, Jennifer A; Allamargot, Chantal; Comellas, Alejandro P

    2011-04-01

    During pulmonary edema, the alveolar space is exposed to a hypoxic environment. The integrity of the alveolar epithelial barrier is required for the reabsorption of alveolar fluid. Tight junctions (TJ) maintain the integrity of this barrier. We set out to determine whether hypoxia creates a dysfunctional alveolar epithelial barrier, evidenced by an increase in transepithelial electrical conductance (G(t)), due to a decrease in the abundance of TJ proteins at the plasma membrane. Alveolar epithelial cells (AEC) exposed to mild hypoxia (Po(2) = 50 mmHg) for 30 and 60 min decreased occludin abundance at the plasma membrane and significantly increased G(t). Other cell adhesion molecules such as E-cadherin and claudins were not affected by hypoxia. AEC exposed to hypoxia increased superoxide, but not hydrogen peroxide (H(2)O(2)). Overexpression of superoxide dismutase 1 (SOD1) but not SOD2 prevented the hypoxia-induced G(t) increase and occludin reduction in AEC. Also, overexpression of catalase had a similar effect as SOD1, despite not detecting any increase in H(2)O(2) during hypoxia. Blocking PKC-ζ and protein phosphatase 2A (PP2A) prevented the hypoxia-induced occludin reduction at the plasma membrane and increase in G(t). In summary, we show that superoxide, PKC-ζ, and PP2A are involved in the hypoxia-induced increase in G(t) and occludin reduction at the plasma membrane in AEC. PMID:21257729

  16. REGULATION OF CYTOKINE PRODUCTION IN HUMAN ALVEOLAR MACHROPHAGES AND AIRWAY EPITHELIAL CELLS IN RESPONSE TO AMBIENT AIR POLLUTION PARTICLES: FURTHER MECHANISTIC STUDIES

    EPA Science Inventory

    In order to better understand how ambient air particulate matter (PM) affect lung health, the two main airway cell types likely to interact with inhaled particles, alveolar macrophages (AM) and airway epithelial cells have been exposed to particles in vitro and followed for endp...

  17. Spectral Monitoring of Surfactant Clearance during Alveolar Epithelial Type II Cell Differentiation

    PubMed Central

    Swain, Robin J.; Kemp, Sarah J.; Goldstraw, Peter; Tetley, Teresa D.; Stevens, Molly M.

    2008-01-01

    In this study, we report on the noninvasive identification of spectral markers of alveolar type II (ATII) cell differentiation in vitro using Raman microspectroscopy. ATII cells are progenitor cells for alveolar type I (ATI) cells in vivo, and spontaneously differentiate toward an ATI-like phenotype in culture. We analyzed undifferentiated and differentiated primary human ATII cells, and correlated Raman spectral changes to cellular changes in morphology and marker protein synthesis (surfactant protein C, alkaline phosphatase, caveolin-1). Undifferentiated ATII cells demonstrated spectra with strong phospholipid vibrations, arising from alveolar surfactant stored within cytoplasmic lamellar bodies (Lbs). Differentiated ATI-like cells yielded spectra with significantly less lipid content. Factor analysis revealed a phospholipid-dominated spectral component as the main discriminator between the ATII and ATI-like phenotypes. Spectral modeling of the data revealed a significant decrease in the spectral contribution of cellular lipids—specifically phosphatidyl choline, the main constituent of surfactant, as ATII cells differentiate. These observations were consistent with the clearance of surfactant from Lbs as ATII cells differentiate, and were further supported by cytochemical staining for Lbs. These results demonstrate the first spectral characterization of primary human ATII cells, and provide insight into the biochemical properties of alveolar surfactant in its unperturbed cellular environment. PMID:18820234

  18. Analysis of TGF-β1- and drug-induced epithelial-mesenchymal transition in cultured alveolar epithelial cell line RLE/Abca3.

    PubMed

    Takano, Mikihisa; Yamamoto, Chieko; Yamaguchi, Koki; Kawami, Masashi; Yumoto, Ryoko

    2015-02-01

    In this study, we examined the induction of epithelial-mesenchymal transition (EMT) by transforming growth factor (TGF)-β1 and drugs in genetically engineered type II alveolar epithelial cell line RLE/Abca3. Treatment of RLE/Abca3 cells with TGF-β1 induced marked changes in cell morphology from epithelial-like to elongated fibroblast-like morphology. With these morphological changes, mRNA expression of epithelial markers such as cytokeratin 19 (CK19) decreased, while that of mesenchymal markers such as α-smooth muscle actin (α-SMA) increased. TGF-β1 treatment also decreased the mRNA expression of Abca3, a type II cell marker, and formation of lamellar body structures. Interestingly, the effect of TGF-β1 on Abca3 mRNA expression was observed in RLE/Abca3 cells, but not in wild-type RLE-6TN, A549, and H441 cells. Treatment of RLE/Abca3 cells with bleomycin (BLM) and methotrexate (MTX) induced similar morphological and mRNA expression changes. In addition, the increase in α-SMA and the decrease in Abca3 mRNA expression by these drugs were observed only in RLE/Abca3 cells. These findings suggest that, like TGF-β1, BLM and MTX induce EMT in RLE/Abca3 cells, and RLE/Abca3 cells would be a good model to study drug-induced EMT. The effect of pirfenidone, an antifibrotic and anti-inflammatory drug, on EMT induced by TGF-β1 was also discussed. PMID:25760538

  19. Epithelial stem cells and implications for wound repair.

    PubMed

    Plikus, Maksim V; Gay, Denise L; Treffeisen, Elsa; Wang, Anne; Supapannachart, Rarinthip June; Cotsarelis, George

    2012-12-01

    Activation of epithelial stem cells and efficient recruitment of their proliferating progeny plays a critical role in cutaneous wound healing. The reepithelialized wound epidermis has a mosaic composition consisting of progeny that can be traced back both to epidermal and several types of hair follicle stem cells. The contribution of hair follicle stem cells to wound epidermis is particularly intriguing as it involves lineage identity change from follicular to epidermal. Studies from our laboratory show that hair follicle-fated bulge stem cells commit only transient amplifying epidermal progeny that participate in the initial wound re-epithelialization, but eventually are outcompeted by other epidermal clones and largely disappear after a few months. Conversely, recently described stem cell populations residing in the isthmus portion of hair follicle contribute long-lasting progeny toward wound epidermis and, arguably, give rise to new interfollicular epidermal stem cells. The role of epithelial stem cells during wound healing is not limited to regenerating stratified epidermis. By studying regenerative response in large cutaneous wounds, our laboratory uncovered that epithelial cells in the center of the wound can acquire greater morphogenetic plasticity and, together with the underlying wound dermis, can engage in an embryonic-like process of hair follicle neogenesis. Future studies should uncover the cellular and signaling basis of this remarkable adult wound regeneration phenomenon. PMID:23085626

  20. Epithelial Stem Cells and Implications for Wound Repair

    PubMed Central

    Plikus, Maksim V.; Gay, Denise L.; Treffeisen, Elsa; Wang, Anne; Supapannachart, Rarinthip June; Cotsarelis, George

    2012-01-01

    Activation of epithelial stem cells and efficient recruitment of their proliferating progeny plays a critical role in cutaneous wound healing. The reepithelialized wound epidermis hasa mosaic composition consisting of progeny that can be traced back both to epidermal and several types of hair follicle stem cells. The contribution of hair follicle stem cells to wound epidermis is particularly intriguing as it involves lineage identity change from follicular to epidermal. Studies from our laboratory show that hair follicle-fated bulge stem cells commit only transient amplifying epidermal progeny that participate in the initial wound re-epithelialization, but eventually are outcompeted by other epidermal clones and largely disappear after a few months. Conversely, recently described stem cell populations residing in the isthmus portion of hair follicle contribute long-lasting progeny toward wound epidermis and, arguably, give rise to new inter-follicular epidermal stem cells. The role of epithelial stem cells during wound healing is not limited to regenerating stratified epidermis. By studying regenerative response in large cutaneous wounds, our laboratory uncovered that epithelial cells in the center of the wound can acquire greater morphogenetic plasticity and, together with the underlying wound dermis, can engage in an embryonic-like process of hair follicle neogenesis. Future studies should uncover cellular and signaling basis of this remarkable adult wound regeneration phenomenon. PMID:23085626

  1. Airway epithelial repair in health and disease: Orchestrator or simply a player?

    PubMed

    Iosifidis, Thomas; Garratt, Luke W; Coombe, Deirdre R; Knight, Darryl A; Stick, Stephen M; Kicic, Anthony

    2016-04-01

    Epithelial cells represent the most important surface of contact in the body and form the first line of defence of the body to external environment. Consequently, epithelia have numerous roles in order to maintain a homeostatic defence barrier. Although the epithelium has been extensively studied over several decades, it remains the focus of new research, indicating a lack of understanding that continues to exist around these cells in specific disease settings. Importantly, evidence is emerging that airway epithelial cells in particular have varied complex functions rather than simple passive roles. One area of current interest is its role following injury. In particular, the epithelial-specific cellular mechanisms regulating their migration during wound repair remain poorly understood and remain an area that requires much needed investigation. A better understanding of the physiological, cellular and molecular wound repair mechanisms could assist in elucidating pathological processes that contribute to airway epithelial pathology. This review attempts to highlight migration-specific and cell-extracellular matrix (ECM) aspects of repair used by epithelial cells under normal and disease settings, in the context of human airways. PMID:26804630

  2. Lipopolysaccharide-induced cytokine expression in alveolar epithelial cells: role of PKCζ-mediated p47phox phosphorylation.

    PubMed

    Leverence, Jeremy T; Medhora, Meetha; Konduri, Girija G; Sampath, Venkatesh

    2011-01-15

    Chronic inflammation incited by bacteria in the saccular lung of premature infants contributes to the pathogenesis of bronchopulmonary dysplasia (BPD). LPS-mediated type II alveolar epithelial cell (AEC) injury induces the expression of pro-inflammatory cytokines that trigger pulmonary neutrophil influx, alveolar matrix degradation and lung remodeling. We hypothesized that NADPH oxidase (Nox)-dependent mechanisms mediate LPS-induced cytokine expression in AEC. We examined the role of p47phox in mediating LPS-dependent inflammatory cytokine expression in A549 cells (which exhibit phenotypic features characteristic of type II AEC) and elucidated the proximal signaling events by which Nox is activated by LPS. LPS-induced ICAM-1 and IL-8 expression was associated with increased superoxide formation in AEC. LPS-mediated oxidative stress and cytokine expression was inhibited by apocynin and augmented by PMA demonstrating that Nox-dependent redox signaling regulates LPS-dependent pro-inflammatory signaling in AEC. In LPS-treated cells, p47phox translocated from the cytoplasm to the perinuclear region and co-localized with gp91phox. LPS also induced a temporal increase in p47phox serine304 phosphorylation in AEC. While inhibition of classical PKC and novel PKC with calphostin and rottlerin did not inhibit ICAM-1 or IL-8 expression, the myristolyated PKCζ pseudosubstrate peptide (a specific inhibitor of PKCζ) inhibited LPS-induced cytokine expression in AEC. Inhibition of PKCζ also attenuated LPS-mediated p47phox phosphorylation and perinuclear translocation in AEC. Consistent with these data, LPS activated PKCζ in AEC as evidenced by increased threonine410 phophorylation. We conclude that PKCζ-mediated p47phox activation regulates LPS-dependent cytokine expression in AEC. Selective inhibition of PKCζ or p47phox might attenuate LPS-mediated inflammation and alveolar remodeling in BPD. PMID:20920494

  3. Notch induces myofibroblast differentiation of alveolar epithelial cells via transforming growth factor-{beta}-Smad3 pathway.

    PubMed

    Aoyagi-Ikeda, Kana; Maeno, Toshitaka; Matsui, Hiroki; Ueno, Manabu; Hara, Kenichiro; Aoki, Yasuhiro; Aoki, Fumiaki; Shimizu, Takehisa; Doi, Hiroshi; Kawai-Kowase, Keiko; Iso, Tatsuya; Suga, Tatsuo; Arai, Masashi; Kurabayashi, Masahiko

    2011-07-01

    Notch is an ancient cell-signaling system that regulates the specification of cell fate. This study examined the role of Notch in the epithelial-mesenchymal transition (EMT) and myofibroblast differentiation of cultured RLE-6TN cells (i.e., rat alveolar epithelial cells). The activation of Notch, either by ectopic expression of the Notch intracellular domain or by the co-culture of RLE-6TN cells with L-Jagged1 cells, induces the expression of smooth muscle α-actin (SMA) and other mesenchymal marker genes (collagen I and vimentin), and reduces the expression of epithelial marker genes (E-cadherin, occludin, and zonula occludens-1). The pharmacologic inhibition of the endogenous Notch signal significantly inhibited the transforming growth factor-β (TGF-β)-induced expression of SMA. Cell migratory capacity was increased by Notch. Luciferase assays revealed that the CC(A/T)(6)GG (CArG) box and the TGF-β control element (TCE) are required for Notch-induced SMA gene transcription. DNA microarray analysis revealed that members of the TGF-β family as well as Jagged1 were induced in RLE-6TN cells by Notch. Western blot analysis showed that Notch induced the phosphorylation of Smad3, and the TGF-β receptor type I/activin receptor-like kinase 5 (ALK5) kinase inhibitor SB431542 markedly reduced the Notch-induced expression of SMA. Enzyme-linked immunosorbent assays confirmed the production of TGF-β1 from RLE-6TN cells by Notch. Immunohistochemistry of a bleomycin-induced model of pulmonary fibrosis and lung specimens from patients with idiopathic interstitial pneumonias showed that Notch was strongly expressed in myofibroblasts, identified as SMA-positive cells. These data indicate that Notch induces myofibroblast differentiation through a TGF-β-Smad3 pathway that activates SMA gene transcription in a CArG-dependent and TCE-dependent manner in alveolar epithelial cells. Our data also imply that Notch induces the EMT phenotype, with increased migratory behavior in

  4. Staining histological lung sections with Sudan Black B or Sudan III for automated identification of alveolar epithelial type II cells.

    PubMed

    Schneider, Jan Philipp; Pedersen, Lars; Mühlfeld, Christian; Ochs, Matthias

    2015-10-01

    Alveolar epithelial type II (AE2) cells produce, store and secrete pulmonary surfactant and serve as progenitor cells for the alveolar epithelium. They are thus an interesting target in wide fields of pulmonary research. Stereological methods allow their quantification based on measurements on histological sections. A proper AE2 cell quantification, however, requires a method of tissue processing that results in little tissue shrinkage during processing. It was recently shown that a primary fixation with a mixture of glutaraldehyde and formaldehyde, postfixation with osmium tetroxide and uranyl acetate and embedding in glycol methacrylate fulfills this requirement. However, a proper quantification, furthermore, requires a secure identification of the cells under the microscope. Classical approaches using routine stainings, high magnifications and systematic uniform random sampling can result in a tedious counting procedure. In this article we show that Sudan Black B and Sudan III staining in combination with the previously described "low shrinkage method" of tissue processing result in good staining of lamellar bodies of AE2 cells (their storing organelles of surfactant) and thus provide a good signal of AE2 cells, which allows their easy and secure identification even at rather low magnifications. We further show that this signal enables automated detection of AE2 cells by image analysis, which should make this method a suitable staining method for the recently developed and more efficient proportionator sampling. PMID:26558990

  5. Fas activation in alveolar epithelial cells induces KC (CXCL1) release by a MyD88-dependent mechanism.

    PubMed

    Farnand, Alex W; Eastman, Alison J; Herrero, Raquel; Hanson, Josiah F; Mongovin, Steve; Altemeier, William A; Matute-Bello, Gustavo

    2011-09-01

    Activation of the Fas/Fas ligand (FasL) system is associated with activation of apoptotic and proinflammatory pathways that lead to the development of acute lung injury. Previous studies in chimeric mice and macrophage-depleted mice suggested that the main effector cell in Fas-mediated lung injury is not a myeloid cell, but likely an epithelial cell. The goal of this study was to determine whether epithelial cells release proinflammatory cytokines after Fas activation, and to identify the relevant pathways. Incubation of the murine alveolar epithelial cell line, MLE-12, with the Fas-activating monoclonal antibody, Jo2, resulted in release of the CXC chemokine, KC, in a dose-dependent manner. KC release was not prevented by the pan-caspase inhibitor, zVAD.fmk. Silencing of the adaptor protein, MyD88, with small interfering (si)RNA resulted in attenuation of KC release in response to Jo2. Fas activation resulted in phosphorylation of the mitogen-activated kinases extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK), and pharmacologic inhibition of ERK and JNK attenuated KC release in a dose-response manner. Similarly, primary human small airways epithelial cells released IL-8 in response to soluble FasL, and this was abrogated by inhibition of JNK and ERK. In vivo confirmatory studies showed that MyD88-null mice are protected from Fas-induced acute lung injury. In summary, we conclude that Fas induces KC release in MLE-12 cells by a mechanism requiring MyD88, mitogen-activated protein kinases, and likely activator protein-1. PMID:21257927

  6. Mechanisms of suppression of alveolar epithelial cell GM-CSF expression in the setting of hyperoxic stress.

    PubMed

    Sturrock, Anne; Vollbrecht, Timothy; Mir-Kasimov, Mustafa; McManus, Michael; Wilcoxen, Steven E; Paine, Robert

    2010-03-01

    Pulmonary expression of granulocyte/macrophage colony-stimulating factor (GM-CSF) is critically important for normal functional maturation of alveolar macrophages. We found previously that lung GM-CSF is dramatically suppressed in mice exposed to hyperoxia. Alveolar epithelial cells (AEC) are a major source of GM-CSF in the peripheral lung, and in vivo hyperoxia resulted in greatly reduced expression of GM-CSF protein by AEC ex vivo. We now explore the mechanisms responsible for this effect, using primary cultures of murine AEC exposed to hyperoxia in vitro. Exposure of AEC to 80% oxygen/5% CO(2) for 48 h did not induce overt toxicity, but resulted in significantly decreased GM-CSF protein and mRNA expression compared with cells in normoxia. Similar effects were seen when AEC were stressed with serum deprivation, an alternative inducer of oxidative stress. The effects in AEC were opposite those in a murine lung epithelial cell line (MLE-12 cells), in which hyperoxia induced GM-CSF expression. Both hyperoxia and serum deprivation resulted in increased intracellular reactive oxygen species (ROS) in AEC. Hyperoxia and serum deprivation induced significantly accelerated turnover of GM-CSF mRNA. Treatment of AEC with catalase during oxidative stress preserved GM-CSF protein and mRNA and was associated with stabilization of GM-CSF mRNA. We conclude that hyperoxia-induced suppression of AEC GM-CSF expression is a function of ROS-induced destabilization of GM-CSF mRNA. We speculate that AEC oxidative stress results in significantly impaired pulmonary innate immune defense due to effects on local GM-CSF expression in the lung. PMID:20034963

  7. Regulatory effects of hydrogen sulfide on alveolar epithelial cell endoplasmic reticulum stress in rats with acute lung injury

    PubMed Central

    Liu, Zhi-wei; Wang, Hai-ying; Guan, Lan; Zhao, Bin

    2015-01-01

    BACKGROUND: The present study was undertaken to examine the regulatory effect of hydrogen sulfide (H2S) on endoplasmic reticulum stress in alveolar epithelial cells of rats with acute lung injury (ALI) induced by oleic acid (OA). METHODS: Seventy-two male Sprague Dawley (SD) rats were divided into control group, oleic acid-induced ALI group (OA group), oleic acid-induced ALI with sodium hydrosulfide (NaHS) pretreatment group (OA+NaHS group), and sodium hydrosulfide treatment group (NaHS group). Rats of each group were further subdivided into 3 subgroups. Index of quantitative assessment of histological lung injury (IQA), wet/dry weight ratio (W/D) and H2S level of lung tissues were measured. The expressions of endoplasmic reticulum stress markers including glucose-regulated protein 78 (GRP78) and α-subunit of eukaryotic translation initiation factor-2 (elF2α) in lung tissues were measured by immunohistochemical staining and Western blotting. RESULTS: The IQA score and W/D ratio of lung tissues at the three time points significantly increased in rats injected with OA, but significantly decreased in other rats injected with OA and NaHS. The level of H2S in lung tissue at the three time points significantly decreased in rats injected with OA, but significantly increased in other rats injected with both OA and NaHS. GRP78 and elF2α decreased in rats injected with OA, but increased in other rats injected with both OA and NaHS, especially at 4-hour and 6-hour time points. CONCLUSION: The results suggested that H2S could promote alveolar epithelial cell endoplasmic reticulum stress in rats with ALI. PMID:25802570

  8. Role of mitochondrial hydrogen peroxide induced by intermittent hypoxia in airway epithelial wound repair in vitro.

    PubMed

    Hamada, Satoshi; Sato, Atsuyasu; Hara-Chikuma, Mariko; Satooka, Hiroki; Hasegawa, Koichi; Tanimura, Kazuya; Tanizawa, Kiminobu; Inouchi, Morito; Handa, Tomohiro; Oga, Toru; Muro, Shigeo; Mishima, Michiaki; Chin, Kazuo

    2016-05-15

    The airway epithelium acts as a frontline barrier against various environmental insults and its repair process after airway injury is critical for the lung homeostasis restoration. Recently, the role of intracellular reactive oxygen species (ROS) as transcription-independent damage signaling has been highlighted in the wound repair process. Both conditions of continuous hypoxia and intermittent hypoxia (IH) induce ROS. Although IH is important in clinical settings, the roles of IH-induced ROS in the airway repair process have not been investigated. In this study, we firstly showed that IH induced mitochondrial hydrogen peroxide (H2O2) production and significantly decreased bronchial epithelial cell migration, prevented by catalase treatment in a wound scratch assay. RhoA activity was higher during repair process in the IH condition compared to in the normoxic condition, resulting in the cellular morphological changes shown by immunofluorescence staining: round cells, reduced central stress fiber numbers, pronounced cortical actin filament distributions, and punctate focal adhesions. These phenotypes were replicated by exogenous H2O2 treatment under the normoxic condition. Our findings confirmed the transcription-independent role of IH-induced intracellular ROS in the bronchial epithelial cell repair process and might have significant implications for impaired bronchial epithelial cell regeneration. PMID:27093911

  9. In Vivo Epithelial Wound Repair Requires Mobilization of Endogenous Intracellular and Extracellular Calcium*

    PubMed Central

    Aihara, Eitaro; Hentz, Courtney L.; Korman, Abraham M.; Perry, Nicholas P. J.; Prasad, Vikram; Shull, Gary E.; Montrose, Marshall H.

    2013-01-01

    We report that a localized intracellular and extracellular Ca2+ mobilization occurs at the site of microscopic epithelial damage in vivo and is required to mediate tissue repair. Intravital confocal/two-photon microscopy continuously imaged the surgically exposed stomach mucosa of anesthetized mice while photodamage of gastric epithelial surface cells created a microscopic lesion that healed within 15 min. Transgenic mice with an intracellular Ca2+-sensitive protein (yellow cameleon 3.0) report that intracellular Ca2+ selectively increases in restituting gastric epithelial cells adjacent to the damaged cells. Pretreatment with U-73122, indomethacin, 2-aminoethoxydiphenylborane, or verapamil inhibits repair of the damage and also inhibits the intracellular Ca2+ increase. Confocal imaging of Fura-Red dye in luminal superfusate shows a localized extracellular Ca2+ increase at the gastric surface adjacent to the damage that temporally follows intracellular Ca2+ mobilization. Indomethacin and verapamil also inhibit the luminal Ca2+ increase. Intracellular Ca2+ chelation (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid/acetoxymethyl ester, BAPTA/AM) fully inhibits intracellular and luminal Ca2+ increases, whereas luminal calcium chelation (N-(2-hydroxyetheyl)-ethylendiamin-N,N,N′-triacetic acid trisodium, HEDTA) blocks the increase of luminal Ca2+ and unevenly inhibits late-phase intracellular Ca2+ mobilization. Both modes of Ca2+ chelation slow gastric repair. In plasma membrane Ca-ATPase 1+/− mice, but not plasma membrane Ca-ATPase 4−/− mice, there is slowed epithelial repair and a diminished gastric surface Ca2+ increase. We conclude that endogenous Ca2+, mobilized by signaling pathways and transmembrane Ca2+ transport, causes increased Ca2+ levels at the epithelial damage site that are essential to gastric epithelial cell restitution in vivo. PMID:24121509

  10. Pulmonary Alveolar Type II Epithelial Cells and Adult Respiratory Distress Syndrome

    PubMed Central

    Mason, Robert J.

    1985-01-01

    During the past ten years, functions of alveolar type II cells have been well characterized with isolated cells in vitro. Some of the functions were well known from studies in vivo, but others such as transepithelial sodium transport were unsuspected. A better understanding of this important pulmonary cell type improves our knowledge of the pathophysiology of adult respiratory distress syndrome and may in time lead to new therapeutic strategies. ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:3909639

  11. Pirfenidone inhibits p38-mediated generation of procoagulant microparticles by human alveolar epithelial cells.

    PubMed

    Neri, Tommaso; Lombardi, Stefania; Faìta, Francesca; Petrini, Silvia; Balìa, Cristina; Scalise, Valentina; Pedrinelli, Roberto; Paggiaro, Pierluigi; Celi, Alessandro

    2016-08-01

    Pirfenidone is a drug recently approved for idiopathic pulmonary fibrosis but its mechanisms of action are partially unknown. We have previously demonstrated that the airways of patients with idiopathic pulmonary fibrosis contain procoagulant microparticles that activate coagulation factor X to its active form, Xa, a proteinase that signals fibroblast growth and differentiation, thus potentially contributing to the pathogenesis of the disease. We also reported that in vitro exposure of human alveolar cells to H2O2 causes microparticle generation. Since p38 activation is involved in microparticle generation in some cell models and p38 inhibition is one of the mechanisms of action of pirfenidone, we investigated the hypothesis that H2O2-induced generation of microparticles by alveolar cells is dependent on p38 phosphorylation and is inhibited by pirfenidone. H2O2 stimulation of alveolar cells caused p38 phosphorylation that was inhibited by pirfenidone. The drug also inhibited H2O2 induced microparticle generation as assessed by two independent methods (solid phase thrombin generation and flow cytometry). The shedding of microparticle-bound tissue factor activity was also inhibited by pirfenidone. Inhibition of p38-mediated generation of procoagulant microparticle is a previously unrecognized mechanism of action of the antifibrotic drug, pirfenidone. PMID:27237042

  12. Wound repair and anti-oxidative capacity is regulated by ITGB4 in airway epithelial cells.

    PubMed

    Liu, Chi; Liu, Hui-jun; Xiang, Yang; Tan, Yu-rong; Zhu, Xiao-lin; Qin, Xiao-qun

    2010-08-01

    Integrin beta 4 (ITGB4) is a structural adhesion molecule which engages in maintaining the integrity of airway epithelial cells. Its specific cytomembrane structural feature strongly indicates that ITGB4 may engage in many signaling pathways and physiologic processes. However, in addition to adhesion, the specific biologic significance of ITGB4 in airway epithelial cells is almost unknown. In this article, we investigated the expression and functional properties of ITGB4 in airway epithelial cells in vivo and in vitro. Human bronchial epithelial cell line (16HBE14O-cells) and primary rat tracheal epithelial cells (RTE cells) were used to determine ITGB4 expression under ozone tress or mechanical damage, respectively. An ovalbumin (OVA)-challenged asthma model was used to investigate ITGB4 expression after antigen exposure in vivo. In addition, an ITGB4 overexpression vector and ITGB4 silence virus vector were constructed and transfected into RTE cells. Then, wound repair ability and anti-oxidation capacity was evaluated. Our results demonstrated that, on the edge of mechanically wounded cell areas, ITGB4 expression was increased after mechanical injury. After ozone stress, upregulation expression of ITGB4 was also detected. In the OVA-challenged asthma model, ITGB4 expression was decreased on airway epithelial cells accompanying with structural disruption and damage of anti-oxidation capacity. Besides, our study revealed that upregulation of ITGB4 promotes wound repair ability and anti-oxidative ability, while such abilities were blocked when ITGB4 was silenced. Taken together, these results showed that ITGB4 was a new interesting molecule involved in the regulation of wound repair and anti-oxidation processes for airway epithelial cells. PMID:20364299

  13. Brief mechanical ventilation causes differential epithelial repair along the airways of fetal, preterm lambs.

    PubMed

    Deptula, Nicole; Royse, Emily; Kemp, Matthew W; Miura, Yuichiro; Kallapur, Suhas G; Jobe, Alan H; Hillman, Noah H

    2016-08-01

    Mechanical ventilation of preterm lambs causes lung inflammation and injury to the airway epithelium, which is repaired by 15 days after ventilation. In mice, activated basal cells (p63+, KRT14+, KRT8+) initiate injury repair to the trachea, whereas club cells coordinate distal airway repair. In both human and sheep, basal cells line the pseudostratified airways to the distal bronchioles with club cells only present in terminal bronchioles. Mechanical ventilation causes airway epithelial injury that is repaired through basal cell activation in the fetal lung. Ewes at 123 ± 1 day gestational age had the head and chest of the fetus exteriorized and tracheostomy placed. With placental circulation intact, fetal lambs were mechanically ventilated with up to 15 ml/kg for 15 min with 95% N2/5% CO2 Fetal lambs were returned to the uterus for up to 24 h. The trachea, left mainstem bronchi, and peripheral lung were evaluated for epithelial injury and cellular response consistent with repair. Peripheral lung tissue had inflammation, pro-inflammatory cytokine production, epithelial growth factor receptor ligand upregulation, increased p63 expression, and proliferation of pro-SPB, TTF-1 positive club cells. In bronchi, KRT14 and KRT8 mRNA increased without increases in Notch pathway mRNA or proliferation. In trachea, mRNA increased for Notch ligands, SAM pointed domain-containing Ets transcription factor and mucin 5B, but not for basal cell markers. A brief period of mechanical ventilation causes differential epithelial activation between trachea, bronchi, and peripheral lung. The repair mechanisms identified in adult mice occur at different levels of airway branching in fetal sheep with basal and club cell activation. PMID:27343193

  14. DIESEL EXHAUST PARTICLES INDUCE ABERRANT ALVEOLAR EPITHELIAL DIRECTED CELL MOVEMENT BY DISRUPTION OF POLARITY MECHANISMS

    EPA Science Inventory

    Disruption of the respiratory epithelium contributes to the progression of a variety of respiratory diseases that are aggravated by exposure to air pollutants, specifically traffic-based pollutants such as diesel exhaust particles (DEP). Recognizing that lung repair following inj...

  15. IL-8 inhibits cAMP-stimulated alveolar epithelial fluid transport via a GRK2/PI3K-dependent mechanism

    PubMed Central

    Roux, Jérémie; McNicholas, Carmel M.; Carles, Michel; Goolaerts, Arnaud; Houseman, Benjamin T.; Dickinson, Dale A.; Iles, Karen E.; Ware, Lorraine B.; Matthay, Michael A.; Pittet, Jean-François

    2013-01-01

    Patients with acute lung injury (ALI) who retain maximal alveolar fluid clearance (AFC) have better clinical outcomes. Experimental and small clinical studies have shown that β2-adrenergic receptor (β2AR) agonists enhance AFC via a cAMP-dependent mechanism. However, two multicenter phase 3 clinical trials failed to show that β2AR agonists provide a survival advantage in patients with ALI. We hypothesized that IL-8, an important mediator of ALI, directly antagonizes the alveolar epithelial response to β2AR agonists. Short-circuit current and whole-cell patch-clamping experiments revealed that IL-8 or its rat analog CINC-1 decreases by 50% β2AR agonist-stimulated vectorial Cl− and net fluid transport across rat and human alveolar epithelial type II cells via a reduction in the cystic fibrosis transmembrane conductance regulator activity and biosynthesis. This reduction was mediated by heterologous β2AR desensitization and down-regulation (50%) via the G-protein-coupled receptor kinase 2 (GRK2)/PI3K signaling pathway. Inhibition of CINC-1 restored β2AR agonist-stimulated AFC in an experimental model of ALI in rats. Finally, consistent with the experimental results, high pulmonary edema fluid levels of IL-8 (>4000 pg/ml) were associated with impaired AFC in patients with ALI. These results demonstrate a novel role for IL-8 in inhibiting β2AR agonist-stimulated alveolar epithelial fluid transport via GRK2/PI3K-dependent mechanisms.—Roux, J., McNicholas, C. M., Carles, M., Goolaerts, A., Houseman, B. T., Dickinson, D. A., Iles, K. E., Ware, L. B., Matthay, M. A., Pittet, J.-F. IL-8 inhibits cAMP-stimulated alveolar epithelial fluid transport via a GRK2/PI3K-dependent mechanism. PMID:23221335

  16. Evaluation of hydroxylapatite particles in repair of alveolar clefts in dogs.

    PubMed

    Cullum, P E; Frost, D E; Newland, T B; Keane, T M; Ehler, W J

    1988-04-01

    Twelve adult mongrel dogs were used to evaluate the use of hydroxylapatite (HA) in the closure of alveolar clefts. Bilateral alveolar clefts were surgically created in each animal. After healing, they were implanted randomly with either HA or particulate cancellous bone and marrow (PCBM). The results were evaluated clinically, radiographically, and histologically for healing, acceptance of the implant, closure of the fistula, and bony ingrowth. The results show that HA was as successful in closure of the fistulas and re-establishing an intact maxilla as PCBM. Minimal osteoid and bone was interspersed in the HA implant sites. No complications resulted from the HA graft. PMID:2834525

  17. Immunohistochemical characteristics of epithelial cell rests of Malassez during cementum repair.

    PubMed

    Hasegawa, Naohiko; Kawaguchi, Hiroyuki; Ogawa, Tetsuji; Uchida, Takashi; Kurihara, Hidemi

    2003-02-01

    To clarify the roles of epithelial cell rests of Malassez (ECRM) during periodontal repair, experimental root resorption was induced in rats and then the ECRM that existed in periodontal ligament during cementum repair was investigated using morphological and immunohistochemical approaches. At day 7, after mechanical injury, root resorption was observed and ECRM were present adjacent to the site of resorption lacunae. They were observed in periodontal ligament adjacent to site of the resorption lacunae. These ECRM were immunoreactive for bone morphogenetic protein-2. During the stage of early cementum repair, the ECRM were immunoreactive for osteopontin and ameloblastin. They strongly reacted to proliferating cell nuclear antigen. In uninjured control sections, ECRM located in the periodontal ligament adjacent to cementum were not immunoreactive for any antibodies. These findings suggested that ECRM may be related to cementum repair by activating their potential to secrete matrix proteins which have been expressed in tooth development. PMID:12558937

  18. OZONE-INDUCED RELEASE OF CYTOKINES AND FIBRONECTIN BY ALVEOLAR MACROPHAGES AND AIRWAY EPITHELIAL CELLS

    EPA Science Inventory

    Although airway epithelial cells appear damaged following exposure of humans and animals to ozone, the contribution of these cells to inflammation observed after ozone exposure is unclear. ince human airway cells are infrequently available for in vitro studies, we have investigat...

  19. Selective targeting of alveolar type II respiratory epithelial cells by anti-surfactant protein-C antibody-conjugated lipoplexes.

    PubMed

    Wu, Yun; Ma, Junyu; Woods, Parker S; Chesarino, Nicholas M; Liu, Chang; Lee, L James; Nana-Sinkam, Serge P; Davis, Ian C

    2015-04-10

    Alveolar type II (ATII) respiratory epithelial cells are essential to normal lung function. They may be also central to the pathogenesis of diseases such as acute lung injury, pulmonary fibrosis, and pulmonary adenocarcinoma. Hence, ATII cells are important therapeutic targets. However, effective ATII cell-specific drug delivery in vivo requires carriers of an appropriate size, which can cross the hydrophobic alveolar surfactant film and polar aqueous layer overlying ATII cells, and be taken up without inducing ATII cell dysfunction, pulmonary inflammation, lung damage, or excessive systemic spread and side-effects. We have developed lipoplexes as a versatile nanoparticle carrier system for drug/RNA delivery. To optimize their pulmonary localization and ATII cell specificity, lipoplexes were conjugated to an antibody directed against the ATII cell-specific antigen surfactant protein-C (SP-C) then administered to C57BL/6 mice via the nares. Intranasally-administered, anti-SP-C-conjugated lipoplexes targeted mouse ATII cells with >70% specificity in vivo, were retained within ATII cells for at least 48h, and did not accumulate at significant levels in other lung cell types or viscera. 48h after treatment with anti-SP-C-conjugated lipoplexes containing the test microRNA miR-486, expression of mature miR-486 was approximately 4-fold higher in ATII cells than whole lung by qRT-PCR, and was undetectable in other viscera. Lipoplexes induced no weight loss, hypoxemia, lung dysfunction, pulmonary edema, or pulmonary inflammation over a 6-day period. These findings indicate that ATII cell-targeted lipoplexes exhibit all the desired characteristics of an effective drug delivery system for the treatment of pulmonary diseases that result primarily from ATII cell dysfunction. PMID:25687308

  20. Selective targeting of alveolar type II respiratory epithelial cells by anti-surfactant protein-C antibody-conjugated lipoplexes

    PubMed Central

    Wu, Yun; Ma, Junyu; Woods, Parker S.; Chesarino, Nicholas M.; Liu, Chang; Lee, L. James; Nana-Sinkam, Serge P.; Davis, Ian C.

    2015-01-01

    Alveolar type II (ATII) respiratory epithelial cells are essential to normal lung function. They may be also central to the pathogenesis of diseases such as acute lung injury, pulmonary fibrosis, and pulmonary adenocarcinoma. Hence, ATII cells are important therapeutic targets. However, effective ATII cell-specific drug delivery in vivo requires carriers of an appropriate size, which can cross the hydrophobic alveolar surfactant film and polar aqueous layer overlying ATII cells, and be taken up without inducing ATII cell dysfunction, pulmonary inflammation, lung damage, or excessive systemic spread and side-effects. We have developed lipoplexes as a versatile nanoparticle carrier system for drug/RNA delivery. To optimize their pulmonary localization and ATII cell specificity, lipoplexes were conjugated to an antibody directed against the ATII cell-specific antigen surfactant protein-C (SP-C) then administered to C57BL/6 mice via the nares. Intranasally-administered, anti-SP-C-conjugated lipoplexes targeted mouse ATII cells with >70% specificity in vivo, were retained within ATII cells for at least 48 hours, and did not accumulate at significant levels in other lung cell types or viscera. 48 hours after treatment with anti-SP-C-conjugated lipoplexes containing the test microRNA miR-486, expression of mature miR-486 was approximately 4-fold higher in ATII cells than whole lung by qRT-PCR, and was undetectable in other viscera. Lipoplexes induced no weight loss, hypoxemia, lung dysfunction, pulmonary edema, or pulmonary inflammation over a 6-day period. These findings indicate that ATII cell-targeted lipoplexes exhibit all the desired characteristics of an effective drug delivery system for treatment of pulmonary diseases that result primarily from ATII cell dysfunction. PMID:25687308

  1. Cytotoxicity, oxidative stress and genotoxicity induced by glass fibers on human alveolar epithelial cell line A549.

    PubMed

    Rapisarda, Venerando; Loreto, Carla; Ledda, Caterina; Musumeci, Giuseppe; Bracci, Massimo; Santarelli, Lory; Renis, Marcella; Ferrante, Margherita; Cardile, Venera

    2015-04-01

    Man-made vitreous fibers have been widely used as insulation material as asbestos substitutes; however their morphology and composition raises concerns. In 1988 the International Agency for Research on Cancer classified fiberglass, rock wool, slag wool, and ceramic fibers as Group 2B, i.e. possibly carcinogenic to humans. In 2002 it reassigned fiberglass, rock and slag wool, and continuous glass filaments to Group 3, not classifiable as carcinogenic to humans. The aim of this study was to verify the cytotoxic and genotoxic effects and oxidative stress production induced by in vitro exposure of human alveolar epithelial cells A549 to glass fibers with a predominant diameter <3 μm (97%) and length >5 μm (93%). A549 cells were incubated with 5, 50, or 100 μg/ml (2.1, 21, and 42 μg/cm(2), respectively) of glass fibers for 72 h. Cytotoxicity and DNA damage were tested by the MTT and the Comet assay, respectively. Oxidative stress was determined by measuring inducible nitric oxide synthase (iNOS) expression by Western blotting, production of nitric oxide (NO) with Griess reagent, and concentration of reactive oxygen species by fluorescent quantitative analysis with 2',7'-dichlorofluorescein-diacetate (DCFH-DA). The results showed that glass fiber exposure significantly reduced cell viability and increased DNA damage and oxidative stress production in a concentration-dependent manner, demonstrating that glass fibers exert cytotoxic and genotoxic effects related to increased oxidative stress on the human alveolar cell line A549. PMID:25620604

  2. Telomere dysfunction causes alveolar stem cell failure.

    PubMed

    Alder, Jonathan K; Barkauskas, Christina E; Limjunyawong, Nathachit; Stanley, Susan E; Kembou, Frant; Tuder, Rubin M; Hogan, Brigid L M; Mitzner, Wayne; Armanios, Mary

    2015-04-21

    Telomere syndromes have their most common manifestation in lung disease that is recognized as idiopathic pulmonary fibrosis and emphysema. In both conditions, there is loss of alveolar integrity, but the underlying mechanisms are not known. We tested the capacity of alveolar epithelial and stromal cells from mice with short telomeres to support alveolar organoid colony formation and found that type 2 alveolar epithelial cells (AEC2s), the stem cell-containing population, were limiting. When telomere dysfunction was induced in adult AEC2s by conditional deletion of the shelterin component telomeric repeat-binding factor 2, cells survived but remained dormant and showed all the hallmarks of cellular senescence. Telomere dysfunction in AEC2s triggered an immune response, and this was associated with AEC2-derived up-regulation of cytokine signaling pathways that are known to provoke inflammation in the lung. Mice uniformly died after challenge with bleomycin, underscoring an essential role for telomere function in AEC2s for alveolar repair. Our data show that alveoloar progenitor senescence is sufficient to recapitulate the regenerative defects, inflammatory responses, and susceptibility to injury that are characteristic of telomere-mediated lung disease. They suggest alveolar stem cell failure is a driver of telomere-mediated lung disease and that efforts to reverse it may be clinically beneficial. PMID:25840590

  3. Thyroid hormone stimulates Na-K-ATPase activity and its plasma membrane insertion in rat alveolar epithelial cells.

    PubMed

    Lei, Jianxun; Nowbar, Sogol; Mariash, Cary N; Ingbar, David H

    2003-09-01

    Na-K-ATPase protein is critical for maintaining cellular ion gradients and volume and for transepithelial ion transport in kidney and lung. Thyroid hormone, 3,3',5-triiodo-l-thyronine (T3), given for 2 days to adult rats, increases alveolar fluid resorption by 65%, but the mechanism is undefined. We tested the hypothesis that T3 stimulates Na-K-ATPase in adult rat alveolar epithelial cells (AEC), including primary rat alveolar type II (ATII) cells, and determined mechanisms of the T3 effect on the Na-KATPase enzyme using two adult rat AEC cell lines (MP48 and RLE-6TN). T3 at 10-8 and 10-5 M increased significantly hydrolytic activity of Na-K-ATPase in primary ATII cells and both AEC cell lines. The increased activity was dose dependent in the cell lines (10-9-10-4 M) and was detected within 30 min and peaked at 6 h. Maximal increases in Na-K-ATPase activity were twofold in MP48 and RLE-6TN cells at pharmacological T3 of 10-5 and 10-4 M, respectively, but increases were statistically significant at physiological T3 as low as 10-9 M. This effect was T3 specific, because reverse T3 (3,3',5'-triiodo-l-thyronine) at 10-9-10-4 M had no effect. The T3-induced increase in Na-K-ATPase hydrolytic activity was not blocked by actinomycin D. No significant change in mRNA and total cell protein levels of Na-K-ATPase were detected with 10-9-10-5 M T3 at 6 h. However, T3 increased cell surface expression of Na-K-ATPase alpha1- or beta1-subunit proteins by 1.7- and 2-fold, respectively, and increases in Na-K-ATPase activity and cell surface expression were abolished by brefeldin A. These data indicate that T3 specifically stimulates Na-K-ATPase activity in adult rat AEC. The upregulation involves translocation of Na-K-ATPase to plasma membrane, not increased gene transcription. These results suggest a novel nontranscriptional mechanism for regulation of Na-K-ATPase by thyroid hormone. PMID:12740220

  4. Tracking translocation of industrially relevant engineered nanomaterials (ENMs) across alveolar epithelial monolayers in vitro

    PubMed Central

    Cohen, Joel M.; Derk, Raymond; Wang, Liying; Godleski, John; Kobzik, Lester; Brain, Joseph; Demokritou, Philip

    2015-01-01

    Relatively little is known about the fate of industrially relevant engineered nanomaterials (ENMs) in the lungs. Inhalation exposure and subsequent translocation of ENMs across the epithelial lining layer of the lung might contribute to clearance, toxic effects or both. To allow precise quantitation of translocation across lung epithelial cells, we developed a method for tracking industrially-relevant metal oxide ENMs in vitro using neutron activation. The versatility and sensitivity of the proposed In Vitro Epithelial Translocation (INVET) system was demonstrated using a variety of industry relevant ENMs including CeO2 of various primary particle diameter, ZnO, and SiO2-coated-CeO2 and ZnO particles. ENMs were neutron activated, forming gamma emitting isotopes 141Ce and 65Zn respectively. Calu-3 lung epithelial cells cultured to confluency on transwell inserts were exposed to neutron-activated ENM dispersions at sub-lethal doses to investigate the link between ENM properties and translocation potential. The effects of ENM exposure on monolayer integrity was monitored by various methods. ENM translocation across the cellular monolayer was assessed by gamma spectrometry following 2, 4 and 24 hours of exposure. Our results demonstrate that ENMs translocated in small amounts (e.g. <0.01% of the delivered dose at 24 h), predominantly via transcellular pathways without compromising monolayer integrity or disrupting tight junctions. It was also demonstrated that the delivery of particles in suspension to cells in culture is proportional to translocation, emphasizing the importance of accurate dosimetry when comparing ENM-cellular interactions for large panels of materials. The reported INVET system for tracking industrially relevant ENMs while accounting for dosimetry can be a valuable tool for investigating nano-bio interactions in the future. PMID:24479615

  5. Mono- and Cocultures of Bronchial and Alveolar Epithelial Cells Respond Differently to Proinflammatory Stimuli and Their Modulation by Salbutamol and Budesonide.

    PubMed

    Haghi, Mehra; Hittinger, Marius; Zeng, Qingxiang; Oliver, Brian; Traini, Daniela; Young, Paul M; Huwer, Hanno; Schneider-Daum, Nicole; Lehr, Claus-Michael

    2015-08-01

    The aim of this study was to investigate the changes in transport and effectiveness of salbutamol sulfate (SAL) and budesonide (BD) following stimulation with transforming growth factor-β (TGF-β) in mono- and coculture models of bronchial and alveolar epithelium. Primary bronchial and alveolar epithelial cells, grown at air interface on filters, either as monocultures or in coculture with airway smooth muscle cells or alveolar macrophages, respectively, were stimulated with TGF-β. The biological response was modulated by depositing aerosolized SAL and BD on bronchial and alveolar models, respectively. Barrier integrity, permeability to fluorescein-Na, transport of the deposited drug, and the pharmacological response to SAL (cAMP and IL-8 levels) or BD (IL-6 and -8 levels) were measured. While stimulation with TGF-β did not have any significant effect on the transepithelial electrical resistance and permeability to fluorescein-Na in mono- and coculture models, transport of SAL and BD were affected in cultures from some of the patients (6 out of 12 for bronchial and 2 out of 4 for alveolar cells). The bronchial coculture showed a better responsiveness to SAL in terms of cAMP release than the monoculture. In contrast, the difference between alveolar mono- and cocultures to TGF-β mediated interleukin release and its modulation by BD was less pronounced. Our data point to intrinsic differences in the transport of, and responsiveness to, SAL and BD when epithelial cell cultures originate from different patients. Moreover, if the biological responses (e.g., IL-8, cAMP) involve communication between different cell types, coculture models are more relevant to measure such effects than monocultures. PMID:26147243

  6. CCR2 and CXCR3 agonistic chemokines are differently expressed and regulated in human alveolar epithelial cells type II

    PubMed Central

    Pechkovsky, Dmitri V; Goldmann, Torsten; Ludwig, Corinna; Prasse, Antje; Vollmer, Ekkehard; Müller-Quernheim, Joachim; Zissel, Gernot

    2005-01-01

    The attraction of leukocytes from circulation to inflamed lungs depends on the activation of both the leukocytes and the resident cells within the lung. In this study we determined gene expression and secretion patterns for monocyte chemoattractant protein-1 (MCP-1/CCL2) and T-cell specific CXCR3 agonistic chemokines (Mig/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11) in TNF-α-, IFN-γ-, and IL-1β-stimulated human alveolar epithelial cells type II (AEC-II). AEC-II constitutively expressed high level of CCL2 mRNA in vitro and in situ , and released CCL2 protein in vitro . Treatment of AEC-II with proinflammatory cytokines up-regulated both CCL2 mRNA expression and release of immunoreactive CCL2, whereas IFN-γ had no effect on CCL2 release. In contrast, CXCR3 agonistic chemokines were not detected in freshly isolated AEC-II or in non-stimulated epithelial like cell line A549. IFN-γ, alone or in combination with IL-1β and TNF-α resulted in an increase in CXCL10, CXCL11, and CXCL9 mRNA expression and generation of CXCL10 protein by AEC-II or A549 cells. CXCL10 gene expression and secretion were induced in dose-dependent manner after cytokine-stimulation of AEC-II with an order of potency IFN-γ>>IL-1β ≥ TNF-α. Additionally, we localized the CCL2 and CXCL10 mRNAs in human lung tissue explants by in situ hybridization, and demonstrated the selective effects of cytokines and dexamethasone on CCL2 and CXCL10 expression. These data suggest that the regulation of the CCL2 and CXCL10 expression exhibit significant differences in their mechanisms, and also demonstrate that the alveolar epithelium contributes to the cytokine milieu of the lung, with the ability to respond to locally generated cytokines and to produce potent mediators of the local inflammatory response. PMID:16033640

  7. Protein Kinase A-Iα Regulates Na,K-ATPase Endocytosis in Alveolar Epithelial Cells Exposed to High CO2 Concentrations

    PubMed Central

    Sun, Haiying; Chen, Jiwang; Trejo, Humberto E.; Baker, Margaret A.; Sznajder, Jacob I.

    2013-01-01

    Elevated concentrations of CO2 (hypercapnia) lead to alveolar epithelial dysfunction by promoting Na,K-ATPase endocytosis. In the present report, we investigated whether the CO2/HCO3− activated soluble adenylyl cyclase (sAC) regulates this process. We found that hypercapnia increased the production of cyclic adenosine monophosphate (cAMP) and stimulated protein kinase A (PKA) activity via sAC, which was necessary for Na,K-ATPase endocytosis. During hypercapnia, cAMP was mainly produced in specific microdomains in the proximity of the plasma membrane, leading to PKA Type Iα activation. In alveolar epithelial cells exposed to high CO2 concentrations, PKA Type Iα regulated the time-dependent phosphorylation of the actin cytoskeleton component α-adducin at serine 726. Cells expressing small hairpin RNA for PKAc, dominant-negative PKA Type Iα, small interfering RNA for α-adducin, and α-adducin with serine 726 mutated to alanine prevented Na,K-ATPase endocytosis. In conclusion, we provide evidence for a new mechanism by which hypercapnia via sAC, cAMP, PKA Type Iα, and α-adducin regulates Na,K-ATPase endocytosis in alveolar epithelial cells. PMID:23349050

  8. Protein kinase A-Iα regulates Na,K-ATPase endocytosis in alveolar epithelial cells exposed to high CO(2) concentrations.

    PubMed

    Lecuona, Emilia; Sun, Haiying; Chen, Jiwang; Trejo, Humberto E; Baker, Margaret A; Sznajder, Jacob I

    2013-05-01

    Elevated concentrations of CO2 (hypercapnia) lead to alveolar epithelial dysfunction by promoting Na,K-ATPase endocytosis. In the present report, we investigated whether the CO2/HCO3(-) activated soluble adenylyl cyclase (sAC) regulates this process. We found that hypercapnia increased the production of cyclic adenosine monophosphate (cAMP) and stimulated protein kinase A (PKA) activity via sAC, which was necessary for Na,K-ATPase endocytosis. During hypercapnia, cAMP was mainly produced in specific microdomains in the proximity of the plasma membrane, leading to PKA Type Iα activation. In alveolar epithelial cells exposed to high CO2 concentrations, PKA Type Iα regulated the time-dependent phosphorylation of the actin cytoskeleton component α-adducin at serine 726. Cells expressing small hairpin RNA for PKAc, dominant-negative PKA Type Iα, small interfering RNA for α-adducin, and α-adducin with serine 726 mutated to alanine prevented Na,K-ATPase endocytosis. In conclusion, we provide evidence for a new mechanism by which hypercapnia via sAC, cAMP, PKA Type Iα, and α-adducin regulates Na,K-ATPase endocytosis in alveolar epithelial cells. PMID:23349050

  9. Phagosomal pH and glass fiber dissolution in cultured nasal epithelial cells and alveolar macrophages: a preliminary study.

    PubMed Central

    Johnson, N F

    1994-01-01

    The dissolution rate of glass fibers has been shown to be pH sensitive using in vitro lung fluid simulant models. The current study investigated whether there is a difference in phagosomal pH (ppH) between rat alveolar macrophages (AM) and rat nasal epithelial cells (RNEC) and whether such a difference would influence the dissolution of glass fibers. The ppH was measured in cultured AM and RNEC using flow cytometric, fluorescence-emission rationing techniques with fluorescein-labeled, amorphous silica particles. Glass fiber dissolution was determined in AM and RNEC cultured for 3 weeks with fast dissolving glass fibers (GF-A) or slow dissolving ones (GF-B). The mean diameters of GF-A were 2.7 microns and of GF-B, 2.6 microns, the average length of both fibers was approximately 22 to 25 microns. Dissolution was monitored by measuring the length and diameter of intracellular fibers and estimating the volume, assuming a cylindrical morphology. The ppH of AM was 5.2 to 5.8, and the ppH of RNEC was 7.0 to 7.5. The GF-A dissolved more slowly in RNEC than in AM, and no dissolution was evident in either cell type with GF-B. The volume loss with GF-A after a 3-week culture with AM was 66% compared to 45% for cultured RNEC. These results are different from those obtained using in vitro lung fluid-simulant models where dissolution is faster at higher pH. This difference suggests that dissolution rates of glass fibers in AM should not be applied to the dissolution of fibers in epithelial cells. Images Figure 1. a Figure 1. b Figure 2. a Figure 2. b Figure 3. a Figure 3. b PMID:7882965

  10. Understanding Cellular Mechanisms Underlying Airway Epithelial Repair: Selecting the Most Appropriate Animal Models

    PubMed Central

    Yahaya, B.

    2012-01-01

    Understanding the mechanisms underlying the process of regeneration and repair of airway epithelial structures demands close characterization of the associated cellular and molecular events. The choice of an animal model system to study these processes and the role of lung stem cells is debatable since ideally the chosen animal model should offer a valid comparison with the human lung. Species differences may include the complex three-dimensional lung structures, cellular composition of the lung airway as well as transcriptional control of the molecular events in response to airway epithelium regeneration, and repair following injury. In this paper, we discuss issues related to the study of the lung repair and regeneration including the role of putative stem cells in small- and large-animal models. At the end of this paper, the author discuss the potential for using sheep as a model which can help bridge the gap between small-animal model systems and humans. PMID:23049478

  11. Low-affinity transport of FITC-albumin in alveolar type II epithelial cell line RLE-6TN.

    PubMed

    Tagawa, Maki; Yumoto, Ryoko; Oda, Keisuke; Nagai, Junya; Takano, Mikihisa

    2008-01-01

    FITC-albumin uptake by cultured alveolar type II epithelial cells, RLE-6TN, is mediated by high- and low-affinity transport systems. In this study, characteristics of the low-affinity transport system were evaluated. The uptake of FITC-albumin was time and temperature dependent and was inhibited by metabolic inhibitors and bafilomycin A1. Confocal laser scanning microscopic analysis showed punctate localization of the fluorescence in the cells, which was partly localized in lysosomes. FITC-albumin taken up by the cells gradually degraded over time, as shown by fluoroimage analyzer after SDS-PAGE. The uptake of FITC-albumin by RLE-6TN cells was not inhibited by caveolae-mediated endocytosis inhibitors such as nystatin, but was inhibited by clathrin-mediated endocytosis inhibitors such as phenylarsine oxide. The uptake was also inhibited by potassium depletion and hypertonicity, conditions known to inhibit clathrin-mediated endocytosis. In addition, macropinocytosis inhibitors such as 5-(N-ethyl-N-isopropyl) amiloride inhibited the uptake. These results indicate that the low-affinity transport of FITC-albumin in RLE-6TN cells is at least in part mediated by clathrin-mediated endocytosis, but not by caveolae-mediated endocytosis. Possible involvement of macropinocytosis was also suggested. PMID:18974609

  12. Important factors mediates the adhesion of aspergillus fumigatus to alveolar epithelial cells with E-cadherin.

    PubMed

    Xu, Xiao-Yong; Chen, Fei; Sun, He; Chen, Chen; Zhao, Bei-Lei

    2016-01-01

    Aspergillus is widely distributed in the Earth's biosphere. It has strong adaptive capacity, and lives as saprophytic or parasitic life. This study aims to investigate the role of E-cadherin for adhesion of Aspergillus fumigatus blastospores in a human epithelial cell line (A549) and search the correlated molecule in aspergillus. A. fumigatus blastospores were incubated with the total protein of A549 to investigate the binding of E-cadherin and blastospores followed by an affinity purification procedure. After establishing the adhesion model, the adhesion of A. fumigatus blastospores by A549 cells was evaluated by down-regulating E-cadherin of A549 cells with small interfering RNA (siRNA). FVB mice constructed with E-cadherin down-regulation were infected with aspergillus fumigatus. Preliminary exploration of E-cadherin interacting protein on the surface of aspergillus fumigates by immunoprecipitation and mass spectrometry analysis. E-cadherin was adhered to the surface of A. fumigatus blastospore. Adhesion of the blastospores was reduced by blocking or down-regulating E-cadherin in A549 cells. E-cadherin showed limited significance in the process of mice against aspergillus fumigates. Mass spectrometry (MS) analysis indicated the following proteins AFUA_8G07080, AfA24A6.130c, XP_747789 can bind to E-cadherin. In conclusion, E-cadherin is a receptor for adhesion of A. fumigatus blastospores in epithelial cells. This may open a new approach to treat this fungal infection. PMID:27347350

  13. Important factors mediates the adhesion of aspergillus fumigatus to alveolar epithelial cells with E-cadherin

    PubMed Central

    Xu, Xiao-Yong; Chen, Fei; Sun, He; Chen, Chen; Zhao, Bei-Lei

    2016-01-01

    Aspergillus is widely distributed in the Earth’s biosphere. It has strong adaptive capacity, and lives as saprophytic or parasitic life. This study aims to investigate the role of E-cadherin for adhesion of Aspergillus fumigatus blastospores in a human epithelial cell line (A549) and search the correlated molecule in aspergillus. A. fumigatus blastospores were incubated with the total protein of A549 to investigate the binding of E-cadherin and blastospores followed by an affinity purification procedure. After establishing the adhesion model, the adhesion of A. fumigatus blastospores by A549 cells was evaluated by down-regulating E-cadherin of A549 cells with small interfering RNA (siRNA). FVB mice constructed with E-cadherin down-regulation were infected with aspergillus fumigatus. Preliminary exploration of E-cadherin interacting protein on the surface of aspergillus fumigates by immunoprecipitation and mass spectrometry analysis. E-cadherin was adhered to the surface of A. fumigatus blastospore. Adhesion of the blastospores was reduced by blocking or down-regulating E-cadherin in A549 cells. E-cadherin showed limited significance in the process of mice against aspergillus fumigates. Mass spectrometry (MS) analysis indicated the following proteins AFUA_8G07080, AfA24A6.130c, XP_747789 can bind to E-cadherin. In conclusion, E-cadherin is a receptor for adhesion of A. fumigatus blastospores in epithelial cells. This may open a new approach to treat this fungal infection. PMID:27347350

  14. Disruption of β-catenin/CBP signaling inhibits human airway epithelial-mesenchymal transition and repair.

    PubMed

    Moheimani, Fatemeh; Roth, Hollis M; Cross, Jennifer; Reid, Andrew T; Shaheen, Furquan; Warner, Stephanie M; Hirota, Jeremy A; Kicic, Anthony; Hallstrand, Teal S; Kahn, Michael; Stick, Stephen M; Hansbro, Philip M; Hackett, Tillie-Louise; Knight, Darryl A

    2015-11-01

    The epithelium of asthmatics is characterized by reduced expression of E-cadherin and increased expression of the basal cell markers ck-5 and p63 that is indicative of a relatively undifferentiated repairing epithelium. This phenotype correlates with increased proliferation, compromised wound healing and an enhanced capacity to undergo epithelial-mesenchymal transition (EMT). The transcription factor β-catenin plays a vital role in epithelial cell differentiation and regeneration, depending on the co-factor recruited. Transcriptional programs driven by the β-catenin/CBP axis are critical for maintaining an undifferentiated and proliferative state, whereas the β-catenin/p300 axis is associated with cell differentiation. We hypothesized that disrupting the β-catenin/CBP signaling axis would promote epithelial differentiation and inhibit EMT. We treated monolayer cultures of human airway epithelial cells with TGFβ1 in the presence or absence of the selective small molecule ICG-001 to inhibit β-catenin/CBP signaling. We used western blots to assess expression of an EMT signature, CBP, p300, β-catenin, fibronectin and ITGβ1 and scratch wound assays to assess epithelial cell migration. Snai-1 and -2 expressions were determined using q-PCR. Exposure to TGFβ1 induced EMT, characterized by reduced E-cadherin expression with increased expression of α-smooth muscle actin and EDA-fibronectin. Either co-treatment or therapeutic administration of ICG-001 completely inhibited TGFβ1-induced EMT. ICG-001 also reduced the expression of ck-5 and -19 independent of TGFβ1. Exposure to ICG-001 significantly inhibited epithelial cell proliferation and migration, coincident with a down regulation of ITGβ1 and fibronectin expression. These data support our hypothesis that modulating the β-catenin/CBP signaling axis plays a key role in epithelial plasticity and function. PMID:26315281

  15. Changes in the rat lung after exposure to radon and its progeny: Effects on incorporation of bromodeoxyuridine in epithelial cells and on the incidence of nuclear aberrations in Alveolar macrophages

    SciTech Connect

    Taya, A.; Morgan, A.; Baker, S.T.; Humphreys, J.A.H.; Collier, C.G.; Bisson, M.

    1994-08-01

    The aim of this study was to investigate some responses of cells in the rat respiratory tract as a function of time after inhalation exposure to various levels of radon and its progeny. Rats were exposed to a constant concentration of radon and its progeny to give cumulative exposure levels of 120, 225, 440 and 990 working level months (WLM). An additional unexposed group of rats served as controls. The end points selected for investigation were (a) the incorporation of bromodeoxyuridine (BrdU) in epithelial cells of the conducting airways and of the alveolar region of the respiratory tract and (b) the incidence of alveolar macrophages with nuclear aberrations. After exposure, the incidence of epithelial cells incorporating BrdU-the labeling index-increased in all regions of the respiratory tract examined, but the increase occurred later in alveolar than in airway epithelial cells. The highest labeling index was found in bronchial epithelial cells, which probably received the highest radiation dose. After an initial induction period, the incidence of alveolar macrophages with nuclear aberrations also increased. The possibility of using the labeling index of alveolar and airway epithelial cells, and/or the incidence of nuclear aberrations in alveolar macrophages, to estimate the radiation dose to various regions of the respiratory tract after exposure of rats to radon and its progeny is discussed. 22 refs., 3 figs., 1 tab.

  16. Tissue-engineered endothelial and epithelial implants differentially and synergistically regulate airway repair.

    PubMed

    Zani, Brett G; Kojima, Koji; Vacanti, Charles A; Edelman, Elazer R

    2008-05-13

    The trilaminate vascular architecture provides biochemical regulation and mechanical integrity. Yet regulatory control can be regained after injury without recapitulating tertiary structure. Tissue-engineered (TE) endothelium controls repair even when placed in the perivascular space of injured vessels. It remains unclear from vascular repair studies whether endothelial implants recapitulate the vascular epithelial lining or expose injured tissues to endothelial cells (ECs) with unique healing potential because ECs line the vascular epithelium and the vasa vasorum. We examined this issue in a nonvascular tubular system, asking whether airway repair is controlled by bronchial epithelial cells (EPs) or by ECs of the perfusing bronchial vasculature. Localized bronchial denuding injury damaged epithelium, narrowed bronchial lumen, and led to mesenchymal cell hyperplasia, hypervascularity, and inflammatory cell infiltration. Peribronchial TE constructs embedded with EPs or ECs limited airway injury, although optimum repair was obtained when both cells were present in TE matrices. EC and EP expression of PGE(2), TGFbeta1, TGFbeta2, GM-CSF, IL-8, MCP-1, and soluble VCAM-1 and ICAM-1 was altered by matrix embedding, but expression was altered most significantly when both cells were present simultaneously. EPs may provide for functional control of organ injury and fibrous response, and ECs may provide for preservation of tissue perfusion and the epithelium in particular. Together the two cells optimize functional restoration and healing, suggesting that multiple cells of a tissue contribute to the differentiated biochemical function and repair of a tissue, but need not assume a fixed, ordered architectural relationship, as in intact tissues, to achieve these effects. PMID:18458330

  17. Inducible nitric oxide synthase mediates early epithelial repair of porcine ileum.

    PubMed

    Gookin, Jody L; Rhoads, J Marc; Argenzio, Robert A

    2002-07-01

    Reports conflict regarding the effect of nitric oxide (NO) on intestinal epithelium. In chronic injury, NO appears detrimental by combining with reactive oxygen to form potent-free radicals. In contrast, inhibition of NO synthesis after acute injury exacerbates damage and inflammation. Recent studies have disclosed constitutive expression of inducible NO synthase (iNOS) by normal intestinal epithelia, yet little attention has been given to the role of iNOS in acute epithelial repair. We studied the local effects of iNOS on early epithelial repair of porcine ileal mucosa injured by deoxycholate within Ussing chambers. iNOS was constitutively expressed by the villous epithelium, and after deoxycholate injury, iNOS was expressed by injured and detaching enterocytes. Selective inhibition of iNOS abolished increases in NO synthesis and villous reepithelialization after injury. Exogenous L-arginine rescued baseline reepithelialization from NOS inhibitors but was only capable of stimulating additional repair in the presence of serum. These results demonstrate that iNOS-derived NO is a key mediator of early villous reepithelialization following acute mucosal injury. PMID:12065303

  18. Direct and indirect air particle cytotoxicity in human alveolar epithelial cells.

    PubMed

    Orona, N S; Astort, F; Maglione, G A; Saldiva, P H N; Yakisich, J S; Tasat, D R

    2014-08-01

    Air particulate matter has been associated with adverse impact on the respiratory system leading to cytotoxic and proinflammatory effects. The biological mechanisms behind these associations may be initiated by inhaled small size particles, particle components (soluble fraction) and/or mediators released by particle-exposed cells (conditioned media). The effect of Urban Air Particles from Buenos Aires (UAP-BA) and Residual Oil Fly Ash (ROFA) a surrogate of ambient air pollution, their Soluble Fractions (SF) and Conditioned Media (CM) on A549 lung epithelial cells was examined. After 24 h exposure to TP (10 and 100 μg/ml), SF or CM, several biological parameters were assayed on cultured A549 cells. We tested cell viability by MTT, superoxide anion (O₂(-)) generation by NBT and proinflammatory cytokine (TNFα, IL-6 and IL-8) production by ELISA. UAP-BA particles or its SF (direct effect) did not modify cell viability and generation of O₂(-) for any of the doses tested. On the contrary, UAP-BA CM (indirect effect) reduced cell viability and increased both generation of O₂(-) and IL-8 production. Exposure to ROFA particles, SF or ROFA CM reduced proliferation and O₂(-) but, stimulated IL-8. It is worth to note that UAP-BA and ROFA depicted distinct effects on particle-exposed A549 cells implicating morphochemical dependence. These in vitro findings support the hypothesis that particle-induced lung inflammation and disease may involve lung-derived mediators. PMID:24590061

  19. Induction and repair of DNA strand breaks in bovine lens epithelial cells after high LET irradiation

    NASA Astrophysics Data System (ADS)

    Baumstark-Khan, C.; Heilmann, J.; Rink, H.

    The lens epithelium is the initiation site for the development of radiation induced cataracts. While in the cortex and nucleus radiation interacts with proteins, experimental results from cultured lenses and lens epithelial cells demonstrate mutagenic and cytotoxic effects in the epithelium. It is suggested that incorrectly repaired DNA damage may be lethal in terms of cellular reproduction and also may initiate the development of mutations or transformations in surviving cells. The occurrence of such genetically modified cells may lead to lens opacification. For a quantitative risk estimation for astronauts and space travelers it is necessary to know the radiation's relative biological effectiveness (RBE), because cosmic rays differ significantly from X-rays. RBEs for the induction of DNA strand breaks and the efficiency of repair of these breaks were measured in cultured diploid bovine lens epithelial cells exposed to different LET irradiations. Irradiations were performed either with 300 kV X-rays or at the UNILAC accelerator at GSI. Accelerated ions from Z=8 (O) to Z=92 (U) were used. For strand break measurements hydroxyapatite chromatography of alka-line unwound DNA (overall strand breaks) and non-denaturing filter elution technique (double strand breaks) were applied. Experiments showed that DNA damage occurs as a function of dose, of kinetic energy and of LET. For particles having the same LET the severity of the DNA damage increases with dose. For a given particle dose, as the LET rises, the numbers of DNA strand breaks increase to a maximum and then reach a plateau or decrease. Repair kinetics depend on the fluence (irradiation dose). At any LET value, repair is much slower after heavy ion exposure than after X-irradiation. For ions with an LET of less than 10,000 keV/μm more than 90 percent of the strand breaks induced are repaired within 24 hours. At higher particle fluences, especially for low energetic particles with a very high local density of

  20. Platelet-rich plasma, plasma rich in growth factors and simvastatin in the regeneration and repair of alveolar bone

    PubMed Central

    RIVERA, CÉSAR; MONSALVE, FRANCISCO; SALAS, JUAN; MORÁN, ANDREA; SUAZO, IVÁN

    2013-01-01

    Platelet preparations promote bone regeneration by inducing cell migration, proliferation and differentiation in the area of the injury, which are essential processes for regeneration. In addition, several studies have indicated that simvastatin (SIMV), widely used for the treatment of hypercholesterolemia, stimulates osteogenesis. The objective of this study was to evaluate the effects of treatment with either platelet-rich plasma (PRP) or plasma rich in growth factors (PRGF) in combination with SIMV in the regeneration and repair of alveolar bone. The jaws of Sprague Dawley rats (n=18) were subjected to rotary instrument-induced bone damage (BD). Animals were divided into six groups: BD/H2O (n=3), distilled water without the drug and alveolar bone damage; BD/H2O/PRP (n=3), BD and PRP; BD/H2O/PRGF (n=3), BD and PRGF; BD/SIMV (n=3), BD and water with SIMV; BD/SIMV/PRP (n=3), BD, PRP and SIMV; and BD/SIMV/PRGF (n=3), BD, PRGF and SIMV. Conventional histological analysis (hematoxylin and eosin staining) revealed that the BD/SIMV group showed indicators for mature bone tissue, while the BD/SIMV/PRP and BD/SIMV/PRGF groups showed the coexistence of indicators for mature and immature bone tissue, with no statistical differences between the platelet preparations. Simvastatin did not improve the effect of platelet-rich plasma and plasma rich in growth factors. It was not possible to determine which platelet preparation produced superior effects. PMID:24250728

  1. Image-based finite element modeling of alveolar epithelial cell injury during airway reopening.

    PubMed

    Dailey, H L; Ricles, L M; Yalcin, H C; Ghadiali, S N

    2009-01-01

    The acute respiratory distress syndrome (ARDS) is characterized by fluid accumulation in small pulmonary airways. The reopening of these fluid-filled airways involves the propagation of an air-liquid interface that exerts injurious hydrodynamic stresses on the epithelial cells (EpC) lining the airway walls. Previous experimental studies have demonstrated that these hydrodynamic stresses may cause rupture of the plasma membrane (i.e., cell necrosis) and have postulated that cell morphology plays a role in cell death. However, direct experimental measurement of stress and strain within the cell is intractable, and limited data are available on the mechanical response (i.e., deformation) of the epithelium during airway reopening. The goal of this study is to use image-based finite element models of cell deformation during airway reopening to investigate how cell morphology and mechanics influence the risk of cell injury/necrosis. Confocal microscopy images of EpC in subconfluent and confluent monolayers were used to generate morphologically accurate three-dimensional finite element models. Hydrodynamic stresses on the cells were calculated from boundary element solutions of bubble propagation in a fluid-filled parallel-plate flow channel. Results indicate that for equivalent cell mechanical properties and hydrodynamic load conditions, subconfluent cells develop higher membrane strains than confluent cells. Strain magnitudes were also found to decrease with increasing stiffness of the cell and membrane/cortex region but were most sensitive to changes in the cell's interior stiffness. These models may be useful in identifying pharmacological treatments that mitigate cell injury during airway reopening by altering specific biomechanical properties of the EpC. PMID:19008489

  2. Transplantation of human amniotic epithelial cells repairs brachial plexus injury: pathological and biomechanical analyses

    PubMed Central

    Yang, Qi; Luo, Min; Li, Peng; Jin, Hai

    2014-01-01

    A brachial plexus injury model was established in rabbits by stretching the C6 nerve root. Immediately after the stretching, a suspension of human amniotic epithelial cells was injected into the injured brachial plexus. The results of tensile mechanical testing of the brachial plexus showed that the tensile elastic limit strain, elastic limit stress, maximum stress, and maximum strain of the injured brachial plexuses were significantly increased at 24 weeks after the injection. The treatment clearly improved the pathological morphology of the injured brachial plexus nerve, as seen by hematoxylin eosin staining, and the functions of the rabbit forepaw were restored. These data indicate that the injection of human amniotic epithelial cells contributed to the repair of brachial plexus injury, and that this technique may transform into current clinical treatment strategies. PMID:25657737

  3. Alpha-1 Antitrypsin Mitigates the Inhibition of Airway Epithelial Cell Repair by Neutrophil Elastase.

    PubMed

    Garratt, Luke W; Sutanto, Erika N; Ling, Kak-Ming; Looi, Kevin; Iosifidis, Thomas; Martinovich, Kelly M; Shaw, Nicole C; Buckley, Alysia G; Kicic-Starcevich, Elizabeth; Lannigan, Francis J; Knight, Darryl A; Stick, Stephen M; Kicic, Anthony

    2016-03-01

    Neutrophil elastase (NE) activity is associated with many destructive lung diseases and is a predictor for structural lung damage in early cystic fibrosis (CF), which suggests normal maintenance of airway epithelium is prevented by uninhibited NE. However, limited data exist on how the NE activity in airways of very young children with CF affects function of the epithelia. The aim of this study was to determine if NE activity could inhibit epithelial homeostasis and repair and whether any functional effect was reversible by antiprotease alpha-1 antitrypsin (α1AT) treatment. Viability, inflammation, apoptosis, and proliferation were assessed in healthy non-CF and CF pediatric primary airway epithelial cells (pAECnon-CF and pAECCF, respectively) during exposure to physiologically relevant NE. The effect of NE activity on pAECCF wound repair was also assessed. We report that viability after 48 hours was significantly decreased by 100 nM NE in pAECnon-CF and pAECCF owing to rapid cellular detachment that was accompanied by inflammatory cytokine release. Furthermore, both phenotypes initiated an apoptotic response to 100 nM NE, whereas ≥ 50 nM NE activity significantly inhibited the proliferative capacity of cultures. Similar concentrations of NE also significantly inhibited wound repair of pAECCF, but this effect was reversed by the addition of α1AT. Collectively, our results demonstrate free NE activity is deleterious for epithelial homeostasis and support the hypothesis that proteases in the airway contribute directly to CF structural lung disease. Our results also highlight the need to investigate antiprotease therapies in early CF disease in more detail. PMID:26221769

  4. The role of alveolar epithelial cells in initiating and shaping pulmonary immune responses: communication between innate and adaptive immune systems.

    PubMed

    Chuquimia, Olga D; Petursdottir, Dagbjort H; Rahman, Muhammad J; Hartl, Katharina; Singh, Mahavir; Fernández, Carmen

    2012-01-01

    Macrophages and dendritic cells have been recognized as key players in the defense against mycobacterial infection. However, more recently, other cells in the lungs such as alveolar epithelial cells (AEC) have been found to play important roles in the defense and pathogenesis of infection. In the present study we first compared AEC with pulmonary macrophages (PuM) isolated from mice in their ability to internalize and control Bacillus Calmette-Guérin (BCG) growth and their capacity as APCs. AEC were able to internalize and control bacterial growth as well as present antigen to primed T cells. Secondly, we compared both cell types in their capacity to secrete cytokines and chemokines upon stimulation with various molecules including mycobacterial products. Activated PuM and AEC displayed different patterns of secretion. Finally, we analyzed the profile of response of AEC to diverse stimuli. AEC responded to both microbial and internal stimuli exemplified by TLR ligands and IFNs, respectively. The response included synthesis by AEC of several factors, known to have various effects in other cells. Interestingly, TNF could stimulate the production of CCL2/MCP-1. Since MCP-1 plays a role in the recruitment of monocytes and macrophages to sites of infection and macrophages are the main producers of TNF, we speculate that both cell types can stimulate each other. Also, another cell-cell interaction was suggested when IFNs (produced mainly by lymphocytes) were able to induce expression of chemokines (IP-10 and RANTES) by AEC involved in the recruitment of circulating lymphocytes to areas of injury, inflammation, or viral infection. In the current paper we confirm previous data on the capacity of AEC regarding internalization of mycobacteria and their role as APC, and extend the knowledge of AEC as a multifunctional cell type by assessing the secretion of a broad array of factors in response to several different types of stimuli. PMID:22393384

  5. Aerosolized ZnO nanoparticles induce toxicity in alveolar type II epithelial cells at the air-liquid interface

    SciTech Connect

    Xie, Yumei; Williams, Nolann G.; Tolic, Ana; Chrisler, William B.; Teeguarden, Justin G.; Maddux, Bettye L.; Pounds, Joel G.; Laskin, Alexander; Orr, Galya

    2012-01-20

    The majority of in vitro studies characterizing the impact of engineered nanoparticles (NPs) on cells that line the respiratory tract were conducted in cells exposed to NPs in suspension. This approach introduces processes that are unlikely to occur during inhaled NP exposures in vivo, such as the shedding of toxic doses of dissolved ions. ZnO NPs are used extensively and pose significant sources for human exposure. Exposures to airborne ZnO NPs can induce adverse effects, but the relevance of the dissolved Zn2+ to the observed effects in vivo is still unclear. Our goal was to mimic in vivo exposures to airborne NPs and decipher the contribution of the intact NP from the contribution of the dissolved ions to airborne ZnO NP toxicity. We established the exposure of alveolar type II epithelial cells to aerosolized NPs at the air-liquid interface (ALI), and compared the impact of aerosolized ZnO NPs and NPs in suspension at the same cellular doses, measured as the number of particles per cell. By evaluating membrane integrity and cell viability 6 and 24 hours post exposure we found that aerosolized NPs induced toxicity at the ALI at doses that were in the same order of magnitude as doses required to induce toxicity in submersed cultures. In addition, distinct patterns of oxidative stress were observed in the two exposure systems. These observations unravel the ability of airborne ZnO NPs to induce toxicity without the contribution of dissolved Zn2+ and suggest distinct mechanisms at the ALI and in submersed cultures.

  6. Differential regulation of epidermal growth factor receptor by hydrogen peroxide and flagellin in cultured lung alveolar epithelial cells.

    PubMed

    Nishi, Hiroyuki; Maeda, Noriko; Izumi, Shunsuke; Higa-Nakamine, Sayomi; Toku, Seikichi; Kakinohana, Manabu; Sugahara, Kazuhiro; Yamamoto, Hideyuki

    2015-02-01

    In previous studies, we found that stimulation of Toll-like receptor 5 (TLR5) by flagellin induced the activation of mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MAPKAPK-2) through activation of the p38 MAPK pathway in cultured alveolar epithelial A549 cells. Our studies strongly suggested that MAPKAPK-2 phosphorylated epidermal growth factor receptor (EGFR) at Ser1047. It has been reported that phosphorylation of Ser1047 after treatment with tumor necrosis factor α (TNFα) induced the internalization of EGFR. In the present study, we first found that treatment of A549 cells with hydrogen peroxide induced the activation of MAPKAPK-2 and phosphorylation of EGFR at Ser1047 within 30 min. This was different from flagellin treatment because hydrogen peroxide treatment induced the phosphorylation of EGFR at Tyr1173 as well as Ser1047, indicating the activation of EGFR. We also found that KN93, an inhibitor of CaM kinase II, inhibited the hydrogen peroxide-induced phosphorylation of EGFR at Ser1047 through inhibition of the activation of the p38 MAPK pathway. Furthermore, we examined the internalization of EGFR by three different methods. Flow cytometry with an antibody against the extracellular domain of EGFR and biotinylation of cell surface proteins revealed that flagellin, but not hydrogen peroxide, decreased the amount of cell-surface EGFR. In addition, activation of extracellular signal-regulated kinase by EGF treatment was reduced by flagellin pre-treatment. These results strongly suggested that hydrogen peroxide activated the p38 MAPK pathway via activation of CaM kinase II and that flagellin and hydrogen peroxide regulate the functions of EGFR by different mechanisms. PMID:25542757

  7. The effect of TGF-β1 and Smad7 gene transfer on the phenotypic changes of rat alveolar epithelial cells.

    PubMed

    Xu, Guo-Ping; Li, Qing-Quan; Cao, Xi-Xi; Chen, Qi; Zhao, Zhong-Hua; Diao, Zi-Qiang; Xu, Zu-De

    2007-09-01

    The aim of this study was to investigate whether transforming growth factor-β1 (TGF-β1) could induce alveolar epithelial-mesenchymal transition (EMT) in vitro, and whether Smad7 gene transfer could block this transition. We also aimed to elucidate the possible mechanisms of these processes. The Smad7 gene was transfected to the rat type II alveolar epithelial cell line (RLE-6TN). Expression of the EMT-associated markers was assayed by Western Blot and Real-time PCR. Morphological alterations were examined via phase-contrast microscope and fluorescence microscope, while ultrastructural changes were examined via electron microscope. TGF-β1 treatment induced a fibrotic phenotype of RLE-6TN with increased expression of fibronectin (FN), α-smooth muscle actin (α-SMA) and vimentin, and decreased expression of E-cadherin (E-cad) and cytokeratin19 (CK19). After transfecting the RLE-6TN with the Smad7 gene, the expression of the mesenchymal markers was downregulated while that of the epithelial markers was upregulated. TGF-β1 treatment for 48 h resulted in the separation of RLE-6TN from one another and a change into elongated, myofibroblast-like cells. After the RLE-6TN had been transfected with the Smad7 gene, TGF-β1 treatment had no effect on the morphology of the RLE-6TN. TGF-β1 treatment for 48 h resulted in an abundant expression of α-SMA in the RLE-6TN. If the RLE-6TN were transfected with the Smad7 gene, TGF-β1 treatment for 48 h could only induce a low level of α-SMA expression. Furthermore, TGF-β1 treatment for 12 h resulted in the degeneration and swelling of the osmiophilic multilamellar bodies, which were the markers of type II alveolar epithelial cells. TGF-β1 can induce alveolar epithelial-mesenchymal transition in vitro, which is dependent on the Smads signaling pathway to a certain extent. Overexpression of the Smad7 gene can partially block this process. PMID:17457524

  8. IL-1β stimulation of CCD-18co myofibroblasts enhances repair of epithelial monolayers through Wnt-5a.

    PubMed

    Raymond, Meera; Marchbank, Tania; Moyer, Mary P; Playford, Raymond J; Sanderson, Ian R; Kruidenier, Laurens

    2012-12-01

    Subepithelial myofibroblasts are involved in the initiation and coordination of intestinal epithelial repair, but the molecular signaling pathways are largely unknown. The cellular adaptations that occur during repair range from dedifferentiation and migration to proliferation and redifferentiation, in a way that is strongly reminiscent of normal crypt-to-villus epithelial maturation. We therefore hypothesized that Wnt/β-catenin signaling may have a pivotal role in intestinal epithelial wound repair. We used the established scratch wound method in Caco-2 cells and in nontransformed NCM460 cells to monitor the effects of IL-1β-stimulated colonic myofibroblasts (CCD-18co) on intestinal epithelial repair, with immunoblotting and immunodepletion to examine the conditioned media. Conditioned media from IL-1β-stimulated, but not -untreated, myofibroblasts increased Caco-2 wound closure twofold over 24 h. IL-1β-stimulated myofibroblasts downregulated the differentiation marker sucrase-isomaltase in the Caco-2 cells, whereas the proliferation marker c-myc was upregulated. Array expression profiling identified Wnt-5a as the Wnt-related gene that was most upregulated (28-fold) by IL-1β stimulation of CCDs. Recombinant Wnt-5a enhanced proliferation of Caco-2 and NCM460 cells. In scratch assays, it increased migration of the leading edge in both cell lines. Wnt-5a immunodepletion of the IL-1β-CCD conditioned media abrogated the ability to enhance the repair. Wnt-5a often acts through a noncanonical signal transduction pathway. Further experiments supported this pathway in epithelial wound healing: IL-1β-CCD-mediated repair was not affected by the addition of the canonical Wnt antagonist Dickkopf-1. Furthermore, media from stimulated myofibroblasts (but not Wnt-5a-depleted media) increased c-jun in Caco-2 cell nuclear extracts. Myofibroblast-mediated noncanonical Wnt-5a signaling is therefore important in the dedifferentiation and migration stages of epithelial wound

  9. Alveolar Epithelial Cells Are Critical in Protection of the Respiratory Tract by Secretion of Factors Able To Modulate the Activity of Pulmonary Macrophages and Directly Control Bacterial Growth

    PubMed Central

    Petursdottir, Dagbjort H.; Periolo, Natalia; Fernández, Carmen

    2013-01-01

    The respiratory epithelium is a physical and functional barrier actively involved in the clearance of environmental agents. The alveolar compartment is lined with membranous pneumocytes, known as type I alveolar epithelial cells (AEC I), and granular pneumocytes, type II alveolar epithelial cells (AEC II). AEC II are responsible for epithelial reparation upon injury and ion transport and are very active immunologically, contributing to lung defense by secreting antimicrobial factors. AEC II also secrete a broad variety of factors, such as cytokines and chemokines, involved in activation and differentiation of immune cells and are able to present antigen to specific T cells. Another cell type important in lung defense is the pulmonary macrophage (PuM). Considering the architecture of the alveoli, a good communication between the external and the internal compartments is crucial to mount effective responses. Our hypothesis is that being in the interface, AEC may play an important role in transmitting signals from the external to the internal compartment and in modulating the activity of PuM. For this, we collected supernatants from AEC unstimulated or stimulated in vitro with lipopolysaccharide (LPS). These AEC-conditioned media were used in various setups to test for the effects on a number of macrophage functions: (i) migration, (ii) phagocytosis and intracellular control of bacterial growth, and (iii) phenotypic changes and morphology. Finally, we tested the direct effect of AEC-conditioned media on bacterial growth. We found that AEC-secreted factors had a dual effect, on one hand controlling bacterial growth and on the other hand increasing macrophage activity. PMID:23147039

  10. Alveolar Epithelial Cell-Derived Prostaglandin E2 Serves as a Request Signal for Macrophage Secretion of Suppressor of Cytokine Signaling 3 during Innate Inflammation.

    PubMed

    Speth, Jennifer M; Bourdonnay, Emilie; Penke, Loka Raghu Kumar; Mancuso, Peter; Moore, Bethany B; Weinberg, Jason B; Peters-Golden, Marc

    2016-06-15

    Preservation of gas exchange mandates that the pulmonary alveolar surface restrain unnecessarily harmful inflammatory responses to the many challenges to which it is exposed. These responses reflect the cross-talk between alveolar epithelial cells (AECs) and resident alveolar macrophages (AMs). We recently determined that AMs can secrete suppressor of cytokine signaling (SOCS) proteins within microparticles. Uptake of these SOCS-containing vesicles by epithelial cells inhibits cytokine-induced STAT activation. However, the ability of epithelial cells to direct AM release of SOCS-containing vesicles in response to inflammatory insults has not been studied. In this study, we report that SOCS3 protein was elevated in bronchoalveolar lavage fluid of both virus- and bacteria-infected mice, as well as in an in vivo LPS model of acute inflammation. In vitro studies revealed that AEC-conditioned medium (AEC-CM) enhanced AM SOCS3 secretion above basal levels. Increased amounts of PGE2 were present in AEC-CM after LPS challenge, and both pharmacologic inhibition of PGE2 synthesis in AECs and neutralization of PGE2 in AEC-CM implicated this prostanoid as the major AEC-derived factor mediating enhanced AM SOCS3 secretion. Moreover, pharmacologic blockade of PGE2 synthesis or genetic deletion of a PGE2 synthase similarly attenuated the increase in bronchoalveolar lavage fluid SOCS3 noted in lungs of mice challenged with LPS in vivo. These results demonstrate a novel tunable form of cross-talk in which AECs use PGE2 as a signal to request SOCS3 from AMs to dampen their endogenous inflammatory responses during infection. PMID:27183597

  11. Induction and repair of DNA strand breaks in bovine lens epithelial cells after high LET irradiation

    NASA Astrophysics Data System (ADS)

    Baumstark-Khan, C.; Heilmann, J.; Rink, H.

    The lens epithelium is the initiation site for the development of radiation induced cataracts. Radiation in the cortex and nucleus interacts with proteins, while in the epithelium, experimental results reveal mutagenic and cytotoxic effects. It is suggested that incorrectly repaired DNA damage may be lethal in terms of cellular reproduction and also may initiate the development of mutations or transformations in surviving cells. The occurrence of such genetically modified cells may lead to lens opacification. For a quantitative risk estimation for astronauts and space travelers it is necessary to know the relative biological effectiveness (RBE), because the spacial and temporal distribution of initial physical damage induced by cosmic radiation differ significantly from that of X-rays. RBEs for the induction of DNA strand breaks and the efficiency of repair of these breaks were measured in cultured diploid bovine lens epithelial cells exposed to different LET irradiation to either 300 kV X-rays or to heavy ions at the UNILAC accelerator at GSI. Accelerated ions from Z=8 (O) to Z=92 (U) were used. Strand breaks were measured by hydroxyapatite chromatography of alkaline unwound DNA (overall strand breaks). Results showed that DNA damage occurs as a function of dose, of kinetic energy and of LET. For particles having the same LET the severity of the DNA damage increases with dose. For a given particle dose, as the LET rises, the numbers of DNA strand breaks increase to a maximum and then reach a plateau or decrease. Repair kinetics depend on the fluence (irradiation dose). At any LET value, repair is much slower after heavy ion exposure than after X-irradiation. For ions with an LET of less than 10,000 keV μ -1 more than 90 percent of the strand breaks induced are repaired within 24 hours. At higher particle fluences, especially for low energetic particles with a very high local density of energy deposition within the particle track, a higher proportion of non

  12. Induction and repair of DNA strand breaks in bovine lens epithelial cells after high LET irradiation.

    PubMed

    Baumstark-Khan, C; Heilmann, J; Rink, H

    2003-01-01

    The lens epithelium is the initiation site for the development of radiation induced cataracts. Radiation in the cortex and nucleus interacts with proteins, while in the epithelium, experimental results reveal mutagenic and cytotoxic effects. It is suggested that incorrectly repaired DNA damage may be lethal in terms of cellular reproduction and also may initiate the development of mutations or transformations in surviving cells. The occurrence of such genetically modified cells may lead to lens opacification. For a quantitative risk estimation for astronauts and space travelers it is necessary to know the relative biological effectiveness (RBE), because the spacial and temporal distribution of initial physical damage induced by cosmic radiation differ significantly from that of X-rays. RBEs for the induction of DNA strand breaks and the efficiency of repair of these breaks were measured in cultured diploid bovine lens epithelial cells exposed to different LET irradiation to either 300 kV X-rays or to heavy ions at the UNILAC accelerator at GSI. Accelerated ions from Z=8 (O) to Z=92 (U) were used. Strand breaks were measured by hydroxyapatite chromatography of alkaline unwound DNA (overall strand breaks). Results showed that DNA damage occurs as a function of dose, of kinetic energy and of LET. For particles having the same LET the severity of the DNA damage increases with dose. For a given particle dose, as the LET rises, the numbers of DNA strand breaks increase to a maximum and then reach a plateau or decrease. Repair kinetics depend on the fluence (irradiation dose). At any LET value, repair is much slower after heavy ion exposure than after X-irradiation. For ions with an LET of less than 10,000 keV micrometers-1 more than 90 percent of the strand breaks induced are repaired within 24 hours. At higher particle fluences, especially for low energetic particles with a very high local density of energy deposition within the particle track, a higher proportion of

  13. Conceptual Approaches to Lung Injury and Repair

    PubMed Central

    Henson, Peter M.; Henson, Jan E.; Janssen, William J.

    2015-01-01

    Lung injury and repair is a broad topic that includes many cell types and is relevant to the pathogenesis of most lung diseases. Here, we focus on injury and repair of the alveolus, the principal function of which is to achieve gas exchange. The many cell types and structures present in the alveolus are discussed, with emphasis on their interactions in both health and disease. We define injury as damage resulting in impaired gas exchange; physiologic repair, then, requires restoration of normal alveolar architecture and function. The role of inflammation in both injury and repair of structural alveolar cells, particularly epithelial cells, as well as mechanisms of resolution of inflammation will be addressed. Finally, emphasis is placed on the importance of addressing quantitatively the dynamic and complex multidirectional interactions between the many alveolar cell types and structures in three dimensions over time and in relating such mechanistic studies to physiologic outcomes and human disease. PMID:25830855

  14. Conceptual approaches to lung injury and repair.

    PubMed

    Zemans, Rachel L; Henson, Peter M; Henson, Jan E; Janssen, William J

    2015-03-01

    Lung injury and repair is a broad topic that includes many cell types and is relevant to the pathogenesis of most lung diseases. Here, we focus on injury and repair of the alveolus, the principal function of which is to achieve gas exchange. The many cell types and structures present in the alveolus are discussed, with emphasis on their interactions in both health and disease. We define injury as damage resulting in impaired gas exchange; physiologic repair, then, requires restoration of normal alveolar architecture and function. The role of inflammation in both injury and repair of structural alveolar cells, particularly epithelial cells, as well as mechanisms of resolution of inflammation will be addressed. Finally, emphasis is placed on the importance of addressing quantitatively the dynamic and complex multidirectional interactions between the many alveolar cell types and structures in three dimensions over time and in relating such mechanistic studies to physiologic outcomes and human disease. PMID:25830855

  15. Establishment of a Clinically Relevant Ex Vivo Mock Cataract Surgery Model for Investigating Epithelial Wound Repair in a Native Microenvironment

    PubMed Central

    Walker, Janice L.; Bleaken, Brigid M.; Wolff, Iris M.; Menko, A. Sue

    2015-01-01

    The major impediment to understanding how an epithelial tissue executes wound repair is the limited availability of models in which it is possible to follow and manipulate the wound response ex vivo in an environment that closely mimics that of epithelial tissue injury in vivo. This issue was addressed by creating a clinically relevant epithelial ex vivo injury-repair model based on cataract surgery. In this culture model, the response of the lens epithelium to wounding can be followed live in the cells’ native microenvironment, and the molecular mediators of wound repair easily manipulated during the repair process. To prepare the cultures, lenses are removed from the eye and a small incision is made in the anterior of the lens from which the inner mass of lens fiber cells is removed. This procedure creates a circular wound on the posterior lens capsule, the thick basement membrane that surrounds the lens. This wound area where the fiber cells were attached is located just adjacent to a continuous monolayer of lens epithelial cells that remains linked to the lens capsule during the surgical procedure. The wounded epithelium, the cell type from which fiber cells are derived during development, responds to the injury of fiber cell removal by moving collectively across the wound area, led by a population of vimentin-rich repair cells whose mesenchymal progenitors are endogenous to the lens1. These properties are typical of a normal epithelial wound healing response. In this model, as in vivo, wound repair is dependent on signals supplied by the endogenous environment that is uniquely maintained in this ex vivo culture system, providing an ideal opportunity for discovery of the mechanisms that regulate repair of an epithelium following wounding. PMID:26132117

  16. Meropenem-RPX7009 Concentrations in Plasma, Epithelial Lining Fluid, and Alveolar Macrophages of Healthy Adult Subjects.

    PubMed

    Wenzler, Eric; Gotfried, Mark H; Loutit, Jeffrey S; Durso, Stephanie; Griffith, David C; Dudley, Michael N; Rodvold, Keith A

    2015-12-01

    The steady-state concentrations of meropenem and the β-lactamase inhibitor RPX7009 in plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) concentrations were obtained in 25 healthy, nonsmoking adult subjects. Subjects received a fixed combination of meropenem (2 g) and RPX7009 (2 g) administered every 8 h, as a 3-h intravenous infusion, for a total of three doses. A bronchoscopy and bronchoalveolar lavage were performed once in each subject at 1.5, 3.25, 4, 6, or 8 h after the start of the last infusion. Meropenem and RPX7009 achieved a similar time course and magnitude of concentrations in plasma and ELF. The mean pharmacokinetic parameters ± the standard deviations of meropenem and RPX7009 determined from serial plasma concentrations were as follows: Cmax = 58.2 ± 10.8 and 59.0 ± 8.4 μg/ml, Vss = 16.3 ± 2.6 and 17.6 ± 2.6 liters; CL = 11.1 ± 2.1 and 10.1 ± 1.9 liters/h, and t1/2 = 1.03 ± 0.15 and 1.27 ± 0.21 h, respectively. The intrapulmonary penetrations of meropenem and RPX7009 were ca. 63 and 53%, respectively, based on the area under the concentration-time curve from 0 to 8 h (AUC0-8) values of ELF and total plasma concentrations. When unbound plasma concentrations were considered, ELF penetrations were 65 and 79% for meropenem and RPX7009, respectively. Meropenem concentrations in AMs were below the quantitative limit of detection, whereas median concentrations of RPX7009 in AMs ranged from 2.35 to 6.94 μg/ml. The results from the present study lend support to exploring a fixed combination of meropenem (2 g) and RPX7009 (2 g) for the treatment of lower respiratory tract infections caused by meropenem-resistant Gram-negative pathogens susceptible to the combination of meropenem-RPX7009. PMID:26349830

  17. Cigarette smoke-induced kinin B1 receptor promotes NADPH oxidase activity in cultured human alveolar epithelial cells.

    PubMed

    Talbot, Sébastien; Lin, James Chi-Jen; Lahjouji, Karim; Roy, Jean-Philippe; Sénécal, Jacques; Morin, André; Couture, Réjean

    2011-07-01

    Pulmonary inflammation is an important pathological feature of tobacco smoke-related lung diseases. Kinin B1 receptor (B1R) is up-regulated in the rat trachea chronically exposed to cigarette-smoke. This study aimed at determining (1) whether exposure to total particulate matter of the cigarette smoke (TPM) can induce B1R in human alveolar epithelial A549 cells, (2) the mechanism of B1R induction, (3) the functionality of de novo synthesized B1R, and (4) the role of B1R in TPM-induced increase of superoxide anion (O₂(●⁻)) level. Results show that A549 cells exposed to 10 μg/ml TPM increased O₂(●⁻) level along with B1R (protein and mRNA) and IL-1β mRNA. In contrast, B2R and TNF-α mRNA were not affected by TPM. The increasing effect of TPM on O₂(●⁻) level was not significantly affected by the B1R antagonist SSR240612. TPM-increased B1R mRNA was prevented by co-treatments with N-acetyl-l-cysteine (potent antioxidant), diphenyleneiodonium (NADPH oxidase inhibitor), IL-1Ra (interleukin-1R antagonist) and SN-50 (specific inhibitor of NF-kB activation) but not by pentoxifylline (TNF-α release inhibitor), indomethacin and niflumic acid (COX-1 and -2 inhibitors). Stimulation of B1R with a selective agonist (des-Arg⁹-BK, 10 μM; 30 min) increased O₂(●⁻)production which was prevented by apocynin and diphenyleneiodonium (NADPH oxidase inhibitors). Data suggest that the increased expression of B1R by TPM in A549 cells is mediated by oxidative stress, IL-1β and NF-kB but not by cyclooxygenases or TNF-α. The amplification of O₂(●⁻) levels via the activation of B1R-NADPH oxidase may exacerbate pulmonary inflammation and contribute to the chronicity of tobacco smoke-related lung diseases. PMID:21600945

  18. Temperature Dependence of Voltage-gated H+ Currents in Human Neutrophils, Rat Alveolar Epithelial Cells, and Mammalian Phagocytes

    PubMed Central

    DeCoursey, Thomas E.; Cherny, Vladimir V.

    1998-01-01

    H+ currents in human neutrophils, rat alveolar epithelial cells, and several mammalian phagocyte cell lines were studied using whole-cell and excised-patch tight-seal voltage clamp techniques at temperatures between 6 and 42°C. Effects of temperature on gating kinetics were distinguished from effects on the H+ current amplitude. The activation and deactivation of H+ currents were both highly temperature sensitive, with a Q10 of 6–9 (activation energy, Ea, ≈ 30–38 kcal/mol), greater than for most other ion channels. The similarity of Ea for channel opening and closing suggests that the same step may be rate determining. In addition, when the turn-on of H+ currents with depolarization was fitted by a delay and single exponential, both the delay and the time constant (τact) had similarly high Q10. These results could be explained if H+ channels were composed of several subunits, each of which undergoes a single rate-determining gating transition. H+ current gating in all mammalian cells studied had similarly strong temperature dependences. The H+ conductance increased markedly with temperature, with Q10 ≥ 2 in whole-cell experiments. In excised patches where depletion would affect the measurement less, the Q10 was 2.8 at >20°C and 5.3 at <20°C. This temperature sensitivity is much greater than for most other ion channels and for H+ conduction in aqueous solution, but is in the range reported for H+ transport mechanisms other than channels; e.g., carriers and pumps. Evidently, under the conditions employed, the rate-determining step in H+ permeation occurs not in the diffusional approach but during permeation through the channel itself. The large Ea of permeation intrinsically limits the conductance of this channel, and appears inconsistent with the channel being a water-filled pore. At physiological temperature, H+ channels provide mammalian cells with an enormous capacity for proton extrusion. PMID:9758867

  19. Enhanced pyrimidine dimer repair in cultured murine epithelial cells transfected with the denV gene of bacteriophage T4.

    PubMed

    Kusewitt, D F; Budge, C L; Ley, R D

    1994-04-01

    The patch size for excision repair of ultraviolet radiation (UV)-induced pyrimidine dimers was determined in cultured murine epithelial cells with normal and enhanced pyrimidine dimer repair capabilities. Cells with enhanced pyrimidine dimer repair were produced by transfecting 308 cells with the denV gene of bacteriophage T4; this gene encodes the enzyme endonuclease V. Pyrimidine dimer repair following exposure to UV from an FS-40 sunlamp was determined by micrococcal dimer-specific nuclease digestion and alkaline sucrose ultracentrifugation. Patch size ws estimated based on the photolytic lability of bromodeoxyuridine-substituted DNA. Excision repair of UV-induced pyrimidine dimers in denV-transfected 308 cells was enhanced two- to threefold. Production of mRNA from the denV gene in cell lines with enhanced repair was confirmed by RNA blotting. In control cells, the patch size for excision repair of DNA photoproducts was estimated to be 34 nucleotides per photoproduct removed; in denV-transfected cells, a smaller average patch size of 10-16 nucleotides per photoproduct removed was calculated. Thus, endonuclease V activity appears to alter not only the extent, but also the nature of excision repair in UV-exposed mammalian epithelial cells. PMID:8151125

  20. Agonist binding to β-adrenergic receptors on human airway epithelial cells inhibits migration and wound repair.

    PubMed

    Peitzman, Elizabeth R; Zaidman, Nathan A; Maniak, Peter J; O'Grady, Scott M

    2015-12-15

    Human airway epithelial cells express β-adrenergic receptors (β-ARs), which regulate mucociliary clearance by stimulating transepithelial anion transport and ciliary beat frequency. Previous studies using airway epithelial cells showed that stimulation with isoproterenol increased cell migration and wound repair by a cAMP-dependent mechanism. In the present study, impedance-sensing arrays were used to measure cell migration and epithelial restitution following wounding of confluent normal human bronchial epithelial (NHBE) and Calu-3 cells by electroporation. Stimulation with epinephrine or the β2-AR-selective agonist salbutamol significantly delayed wound closure and reduced the mean surface area of lamellipodia protruding into the wound. Treatment with the β-AR bias agonist carvedilol or isoetharine also produced a delay in epithelial restitution similar in magnitude to epinephrine and salbutamol. Measurements of extracellular signal-regulated kinase phosphorylation following salbutamol or carvedilol stimulation showed no significant change in the level of phosphorylation compared with untreated control cells. However, inhibition of protein phosphatase 2A activity completely blocked the delay in wound closure produced by β-AR agonists. In Calu-3 cells, where CFTR expression was inhibited by RNAi, salbutamol did not inhibit wound repair, suggesting that β-AR agonist stimulation and loss of CFTR function share a common pathway leading to inhibition of epithelial repair. Confocal images of the basal membrane of Calu-3 cells labeled with anti-β1-integrin (clone HUTS-4) antibody showed that treatment with epinephrine or carvedilol reduced the level of activated integrin in the membrane. These findings suggest that treatment with β-AR agonists delays airway epithelial repair by a G protein- and cAMP-independent mechanism involving protein phosphatase 2A and a reduction in β1-integrin activation in the basal membrane. PMID:26491049

  1. Shp-2 contributes to anti-RSV activity in human pulmonary alveolar epithelial cells by interfering with the IFN-α-induced Jak/Stat1 pathway

    PubMed Central

    Wang, Saisai; Zheng, Gang; Zhao, Lifang; Xu, Feng; Qian, Jing

    2015-01-01

    Src homology phosphotyrosyl phosphatase 2 (Shp-2) is a ubiquitously expressed protein that is involved in a variety of cellular processes, including antiviral interferon signalling pathways. In this study, we investigated the role of Shp-2 in the host cell interactions of human respiratory syncytial virus (RSV). We report significant changes in the expression of Shp-2 in human pulmonary alveolar epithelial cells (A549) upon RSV infection. We also report that blocking Shp-2 does not affect viral replication or virus-induced interferon-alpha (IFN-α) production. Interestingly, whereas A549 cells were activated by IFN-α, the blocking of Shp-2 resulted in increased viral replication that was associated with the reduced expression of the IFN-stimulated genes of 2′,5′-oligoadenylate synthetases and Mx1, and the concomitant inhibition of Stat1 tyrosine phosphorylation. Our findings suggest that Shp-2 contributes to the control of RSV replication and progeny production in pulmonary alveolar epithelial cells by interfering with IFN-α-induced Jak/Stat1 pathway activation rather than by affecting the production of IFN-α itself. PMID:26119280

  2. Alteration in Intrapulmonary Pharmacokinetics of Aerosolized Model Compounds Due to Disruption of the Alveolar Epithelial Barriers Following Bleomycin-Induced Pulmonary Fibrosis in Rats.

    PubMed

    Togami, Kohei; Chono, Sumio; Tada, Hitoshi

    2016-03-01

    Idiopathic pulmonary fibrosis is a lethal lung disease that is characterized by the accumulation of extracellular matrix and a change in lung structure. In this study, intrapulmonary pharmacokinetics of aerosolized model compounds were evaluated using rats with bleomycin-induced pulmonary fibrosis. Aerosol formulations of indocyanine green, 6-carboxyfluorescein (6-CF), and fluorescein isothiocyanate dextrans (FD; 4.4, 10, 70, and 250 kDa) were administered to rat lungs using a MicroSprayer. Indocyanine green fluorescence signals were significantly weaker in fibrotic lungs than in control lungs and 6-CF and FD concentrations in the plasma of pulmonary fibrotic animals were markedly higher than in the plasma of control animals. Moreover, disrupted epithelial tight junctions, including claudins-1, -3, and -5, were observed in pulmonary fibrotic lesions using immunofluorescence microscopy. In addition, destruction of tight junctions on model alveolar epithelial cells (NCI-H441) by transforming growth factor-β1 treatment enhanced the permeability of 6-CF and FDs through NCI-H441 cell monolayers. These results indicate that aerosolized drugs are easily distributed into the plasma after leakage through damaged tight junctions of alveolar epithelium. Therefore, the development of delivery systems for anti-fibrotic agents to improve intrapulmonary pharmacokinetics may be necessary for effective idiopathic pulmonary fibrosis therapy. PMID:26886341

  3. Modeling pulmonary alveolar microlithiasis by epithelial deletion of the Npt2b sodium phosphate cotransporter reveals putative biomarkers and strategies for treatment.

    PubMed

    Saito, Atsushi; Nikolaidis, Nikolaos M; Amlal, Hassane; Uehara, Yasuaki; Gardner, Jason C; LaSance, Kathleen; Pitstick, Lori B; Bridges, James P; Wikenheiser-Brokamp, Kathryn A; McGraw, Dennis W; Woods, Jason C; Sabbagh, Yves; Schiavi, Susan C; Altinişik, Göksel; Jakopović, Marko; Inoue, Yoshikazu; McCormack, Francis X

    2015-11-11

    Pulmonary alveolar microlithiasis (PAM) is a rare, autosomal recessive lung disorder associated with progressive accumulation of calcium phosphate microliths. Inactivating mutations in SLC34A2, which encodes the NPT2b sodium-dependent phosphate cotransporter, has been proposed as a cause of PAM. We show that epithelial deletion of Npt2b in mice results in a progressive pulmonary process characterized by diffuse alveolar microlith accumulation, radiographic opacification, restrictive physiology, inflammation, fibrosis, and an unexpected alveolar phospholipidosis. Cytokine and surfactant protein elevations in the alveolar lavage and serum of PAM mice and confirmed in serum from PAM patients identify serum MCP-1 (monocyte chemotactic protein 1) and SP-D (surfactant protein D) as potential biomarkers. Microliths introduced by adoptive transfer into the lungs of wild-type mice produce marked macrophage-rich inflammation and elevation of serum MCP-1 that peaks at 1 week and resolves at 1 month, concomitant with clearance of stones. Microliths isolated by bronchoalveolar lavage readily dissolve in EDTA, and therapeutic whole-lung EDTA lavage reduces the burden of stones in the lungs. A low-phosphate diet prevents microlith formation in young animals and reduces lung injury on the basis of reduction in serum SP-D. The burden of pulmonary calcium deposits in established PAM is also diminished within 4 weeks by a low-phosphate diet challenge. These data support a causative role for Npt2b in the pathogenesis of PAM and the use of the PAM mouse model as a preclinical platform for the development of biomarkers and therapeutic strategies. PMID:26560359

  4. A Human Espophageal Epithelial Cell Model for Study of Radiation Induced Cancer and DNA Damage Repair

    NASA Technical Reports Server (NTRS)

    Huff, Janice L.; Patel, Zarana S.; Hada, Megumi; Cucinotta, Francis A.

    2008-01-01

    For cancer risk assessment in astronauts and for countermeasure development, it is essential to understand the molecular mechanisms of radiation carcinogenesis and how these mechanisms are influenced by exposure to the types of radiation found in space. We are developing an in vitro model system for the study of radiation-induced initiation and progression of esophageal carcinoma, a type of cancer found to have a significant enhancement in incidence in the survivors of the atomic bomb detonations in Japan. Here we present the results of our preliminary characterization of both normal and hTERT immortalized esophageal epithelial cells grown in 2-dimensional culture. We analyzed DNA repair capacity by measuring the kinetics of formation and loss of - H2AX foci following radiation exposure. Additionally, we analyzed induction of chromosomal aberrations using 3-color fluorescence in situ hybridization (FISH). Data were generated using both low LET (gamma rays) and high LET ions (1000 MeV/nucleon iron).

  5. Changes in Macrophage Phenotype and Induction of Epithelial-to-Mesenchymal Transition Genes Following Acute Achilles Tenotomy and Repair

    PubMed Central

    Sugg, Kristoffer B; Lubardic, Jovan; Gumucio, Jonathan P; Mendias, Christopher L

    2014-01-01

    Tendon injuries occur frequently in physically active individuals, but the clinical outcomes for these injuries can be poor. In many injured tissues the repair process is orchestrated by two types of cells, macrophages and fibroblasts. Macrophages, which have both proinflammatory (M1) and antiinflammatory (M2) phenotypes, can directly participate in tissue remodeling and direct the response of other cells through the secretion of cytokines and growth factors. In many organ systems, epithelial cells can transdifferentiate into fibroblasts, which can then regenerate damaged ECM. This process is triggered via activation of epithelial-to-mesenchymal transition (EMT) signaling programs. Most tendons are surrounded by sheets of epithelial cells, and these tissue layers could provide a source of fibroblasts to repair injured tendons. To gain greater insight into the biology of tendon repair, we performed a tenotomy and repair in Achilles tendons of adult rats and determined changes in macrophage phenotype, and ECM- and EMT-related genes over a four week time course. The results from this study suggest that changes in macrophage phenotype and activation of EMT-related programs likely contribute to the degradation and subsequent repair of injured tendon tissue. PMID:24700411

  6. Changes in macrophage phenotype and induction of epithelial-to-mesenchymal transition genes following acute Achilles tenotomy and repair.

    PubMed

    Sugg, Kristoffer B; Lubardic, Jovan; Gumucio, Jonathan P; Mendias, Christopher L

    2014-07-01

    Tendon injuries occur frequently in physically active individuals, but the clinical outcomes for these injuries can be poor. In many injured tissues the repair process is orchestrated by two types of cells, macrophages and fibroblasts. Macrophages, which have both pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes, can directly participate in tissue remodeling and direct the response of other cells through the secretion of cytokines and growth factors. In many organ systems, epithelial cells can trans-differentiate into fibroblasts, which can then regenerate damaged ECM. This process is triggered via activation of epithelial-to-mesenchymal transition (EMT) signaling programs. Most tendons are surrounded by sheets of epithelial cells, and these tissue layers could provide a source of fibroblasts to repair injured tendons. To gain greater insight into the biology of tendon repair, we performed a tenotomy and repair in Achilles tendons of adult rats and determined changes in macrophage phenotype, and ECM- and EMT-related genes over a 4-week time course. The results from this study suggest that changes in macrophage phenotype and activation of EMT-related programs likely contribute to the degradation and subsequent repair of injured tendon tissue. PMID:24700411

  7. Epithelial cysts associated with alloplastic implants after repair of orbital fractures: a systematic review and four new cases.

    PubMed

    Su, Yun; Sun, Jing; Fan, Xianqun

    2016-07-01

    An epithelial cyst is a rare and often late complication of long-term alloplastic implants, which has the potential to lead to further complications and harm to patients. We made a systematic review of papers published during the past 30 years about the mechanisms and clinical characteristics formation of epithelial cysts after repair of an orbital fracture by searching PubMed, Medline, and Web of Science to collect all related case reports and series published in the English language. We also made a retrospective review of casenotes of all patients diagnosed with orbital epithelial cysts in our department. We found 19 cases of epithelial cysts, including the four cases of our own, associated with alloplastic material, 12 of which were associated with silicone. There were 12 men and seven women aged from 26-71 years old. Orbital cysts developed 15 months-31 (median 8) years after implantation. Histological analysis confirmed that the cysts were all epithelial cysts lined with squamous or respiratory (or both) cells, and differing degrees of chronic inflammation. Epithelial cysts after implantation of alloplastic material may present with various symptoms several years after repair of orbital fractures, and their formation probably results from the synergistic effects of both ectopic cells and chronic inflammation. The implant itself may be a trigger, and the cysts did not seem to be limited to one specific type of implant. PMID:27094498

  8. Lost after translation: insights from pulmonary surfactant for understanding the role of alveolar epithelial dysfunction and cellular quality control in fibrotic lung disease.

    PubMed

    Mulugeta, Surafel; Nureki, Shin-Ichi; Beers, Michael F

    2015-09-15

    Dating back nearly 35 years ago to the Witschi hypothesis, epithelial cell dysfunction and abnormal wound healing have reemerged as central concepts in the pathophysiology of idiopathic pulmonary fibrosis (IPF) in adults and in interstitial lung disease in children. Alveolar type 2 (AT2) cells represent a metabolically active compartment in the distal air spaces responsible for pulmonary surfactant biosynthesis and function as a progenitor population required for maintenance of alveolar integrity. Rare mutations in surfactant system components have provided new clues to understanding broader questions regarding the role of AT2 cell dysfunction in the pathophysiology of fibrotic lung diseases. Drawing on data generated from a variety of model systems expressing disease-related surfactant component mutations [surfactant proteins A and C (SP-A and SP-C); the lipid transporter ABCA3], this review will examine the concept of epithelial dysfunction in fibrotic lung disease, provide an update on AT2 cell and surfactant biology, summarize cellular responses to mutant surfactant components [including endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and intrinsic apoptosis], and examine quality control pathways (unfolded protein response, the ubiquitin-proteasome system, macroautophagy) that can be utilized to restore AT2 homeostasis. This integrated response and its derangement will be placed in the context of cell stress and quality control signatures found in patients with familial or sporadic IPF as well as non-surfactant-related AT2 cell dysfunction syndromes associated with a fibrotic lung phenotype. Finally, the need for targeted therapeutic strategies for pulmonary fibrosis that address epithelial ER stress, its downstream signaling, and cell quality control are discussed. PMID:26186947

  9. Ineffective correction of PPARγ signaling in cystic fibrosis airway epithelial cells undergoing repair.

    PubMed

    Bou Saab, J; Bacchetta, M; Chanson, M

    2016-09-01

    Peroxisome proliferator-activated receptor gamma (PPARγ) represents a potential target to treat airway mucus hypersecretion in cystic fibrosis (CF). We aimed to determine if PPARγ is altered in CF human airway epithelial cells (HAECs), if PPARγ contributes to mucin expression and HAEC differentiation, and if PPARγ ligand therapy corrects the CF phenotype. To this end, well-differentiated CF and NCF HAEC primary cultures were wounded to monitor the expression of key genes involved in PPARγ activation and mucus homeostasis, and to evaluate the effect of a PPARγ agonist, at different times of repair. Hydroxyprostaglandin dehydrogenase (HPGD) converts prostaglandin E2 to 15-keto PGE2 (15kPGE2), an endogenous PPARγ ligand. Interestingly, PPARγ and HPGD expression dramatically decreased in CF HAECs. These changes were accompanied by an increase in the expression of MUC5B. The correlation between PPARγ and MUC5B was confirmed in an airway epithelial cell line after CFTR knock-down. Exposure of HAECs to 15kPGE2 did not correct the CF phenotype but revealed a defect in the process of basal cell (BC) differentiation. The HPGD/PPARγ axis is deregulated in primary HAEC cultures from CF patients, which may impact the maturation of BCs to differentiated luminal cells. Importantly, PPARγ therapy was inefficient in correcting the CF defect. PMID:27484450

  10. IN VITRO LUNG ALVEOLAR EPITHELIAL CELL INJURY AND INFLAMMATORY RESPONSE TO PARTICULATE MATTER-ASSOCIATED METALS - MODULATION BY EXPOSURE TO TNF-ALPHA, IL-BETA, OR IFN-GAMMA

    EPA Science Inventory

    IN VITRO LUNG ALVEOLAR EPITHELIAL CELL INJURY AND INFLAMMATORY RESPONSE TO PARTICULATE MATTER-ASSOCIATED METALS - MODULATION BY EXPOSURE TO TNF , IL-1 , OR IFN .

    JA Dye, KE Peoples*, CL Hayes?. US EPA, ORD, Pulmonary Toxicology Branch, RTP, NC, *HHMI-SRI, NCSU, Raleigh, NC...

  11. BRCA1/FANCD2/BRG1-Driven DNA Repair Stabilizes the Differentiation State of Human Mammary Epithelial Cells.

    PubMed

    Wang, Hua; Bierie, Brian; Li, Andrew G; Pathania, Shailja; Toomire, Kimberly; Dimitrov, Stoil D; Liu, Ben; Gelman, Rebecca; Giobbie-Hurder, Anita; Feunteun, Jean; Polyak, Kornelia; Livingston, David M

    2016-07-21

    An abnormal differentiation state is common in BRCA1-deficient mammary epithelial cells, but the underlying mechanism is unclear. Here, we report a convergence between DNA repair and normal, cultured human mammary epithelial (HME) cell differentiation. Surprisingly, depleting BRCA1 or FANCD2 (Fanconi anemia [FA] proteins) or BRG1, a mSWI/SNF subunit, caused HME cells to undergo spontaneous epithelial-to-mesenchymal transition (EMT) and aberrant differentiation. This also occurred when wild-type HMEs were exposed to chemicals that generate DNA interstrand crosslinks (repaired by FA proteins), but not in response to double-strand breaks. Suppressed expression of ΔNP63 also occurred in each of these settings, an effect that links DNA damage to the aberrant differentiation outcome. Taken together with somatic breast cancer genome data, these results point to a breakdown in a BRCA/FA-mSWI/SNF-ΔNP63-mediated DNA repair and differentiation maintenance process in mammary epithelial cells that may contribute to sporadic breast cancer development. PMID:27373334

  12. Morphologic Damage of Rat Alveolar Epithelial Type II Cells Induced by Bile Acids Could Be Ameliorated by Farnesoid X Receptor Inhibitor Z-Guggulsterone In Vitro

    PubMed Central

    Huang, Yaowei; Hou, Xusheng; Wu, Wenyu; Nie, Lei; Tian, Yinghong; Lu, Yanmeng

    2016-01-01

    Objective. To determine whether bile acids (BAs) affect respiratory functions through the farnesoid X receptor (FXR) expressed in the lungs and to explore the possible mechanisms of BAs-induced respiratory disorder. Methods. Primary cultured alveolar epithelial type II cells (AECIIs) of rat were treated with different concentrations of chenodeoxycholic acid (CDCA) in the presence or absence of FXR inhibitor Z-guggulsterone (GS). Then, expression of FXR in nuclei of AECIIs was assessed by immunofluorescence microscopy. And ultrastructural changes of the cells were observed under transmission electron microscope and analyzed by Image-Pro Plus software. Results. Morphologic damage of AECIIs was exhibited in high BAs group in vitro, with high-level expression of FXR, while FXR inhibitor GS could attenuate the cytotoxicity of BAs to AECIIs. Conclusions. FXR expression was related to the morphologic damage of AECIIs induced by BAs, thus influencing respiratory functions. PMID:27340672

  13. Activation of the heat shock response attenuates the interleukin 1β-mediated inhibition of the amiloride-sensitive alveolar epithelial ion transport.

    PubMed

    Howard, Marybeth; Roux, Jérémie; Iles, Karen E; Miyazawa, Byron; Christiaans, Sarah; Anjum, Naseem; Dickinson, Dale A; Goolaerts, Arnaud; Matthay, Michael A; Pittet, Jean Francois

    2013-02-01

    Acute lung injury (ALI) is a clinical syndrome characterized by hypoxia, which is caused by the breakdown of the alveolar capillary barrier. Interleukin 1β (IL-1β), a cytokine released within the airspace in ALI, downregulates the α subunit of the epithelial sodium channel (αENaC) transcription and protein expression via p38 MAP kinase-dependent signaling. Although induction of the heat shock response can restore alveolar fluid clearance compromised by IL-1β following the onset of severe hemorrhagic shock in rats, the mechanisms are not fully understood. In this study, we report that the induction of the heat shock response prevents IL-1β-dependent inhibition of αENaC mRNA expression and subsequent channel function. Heat shock results in IRAK1 detergent insolubility and a disruption of Hsp90 binding to IRAK1. Likewise, TAK1, another client protein of Hsp90 and signaling component of the IL-1β pathway, is also detergent insoluble after heat shock. Twenty-four hours after heat shock, both IRAK1 and TAK1 are again detergent soluble, which correlates with the IL-1β-dependent p38 activation. Remarkably, IL-1β-dependent p38 activation 24 h after heat shock did not result in an inhibition of αENaC mRNA expression and channel function. Further analysis demonstrates prolonged preservation of αENaC expression by the activation of the heat shock response that involves inducible Hsp70. Inhibition of Hsp70 at 24 h after heat shock results in p38-dependent IL-1β inhibition of αENaC mRNA expression, whereas overexpression of Hsp70 attenuates the p38-dependent IL-1β inhibition of αENaC mRNA expression. These studies demonstrate new mechanisms by which the induction of the heat shock response protects the barrier function of the alveolar epithelium in ALI. PMID:23324889

  14. Mycoplasma bovis isolates recovered from cattle and bison (Bison bison) show differential in vitro effects on PBMC proliferation, alveolar macrophage apoptosis and invasion of epithelial and immune cells.

    PubMed

    Suleman, Muhammad; Prysliak, Tracy; Clarke, Kyle; Burrage, Pat; Windeyer, Claire; Perez-Casal, Jose

    2016-04-15

    In the last few years, several outbreaks of pneumonia, systemically disseminated infection, and high mortality associated with Mycoplasma bovis (M. bovis) in North American bison (Bison bison) have been reported in Alberta, Manitoba, Saskatchewan, Nebraska, New Mexico, Montana, North Dakota, and Kansas. M. bovis causes Chronic Pneumonia and Polyarthritis Syndrome (CPPS) in young, stressed calves in intensively-managed feedlots. M. bovis is not classified as a primary pathogen in cattle, but in bison it appears to be a primary causative agent with rapid progression of disease with fatal outcomes and an average 20% mature herd mortality. Thus, there is a possibility that M. bovis isolates from cattle and bison differ in their pathogenicity. Hence, we decided to compare selected cattle isolates to several bison isolates obtained from clinical cases. We show differences in modulation of PBMC proliferation, invasion of trachea and lung epithelial cells, along with modulation of apoptosis and survival in alveolar macrophages. We concluded that some bison isolates showed less inhibition of cattle and bison PBMC proliferation, were not able to suppress alveolar macrophage apoptosis as efficiently as cattle isolates, and were more or less invasive than the cattle isolate in various cells. These findings provide evidence about the differential properties of M. bovis isolated from the two species and has helped in the selection of bison isolates for genomic sequencing. PMID:27016754

  15. Small airway epithelial cells exposure to printer-emitted engineered nanoparticles induces cellular effects on human microvascular endothelial cells in an alveolar-capillary co-culture model.

    PubMed

    Sisler, Jennifer D; Pirela, Sandra V; Friend, Sherri; Farcas, Mariana; Schwegler-Berry, Diane; Shvedova, Anna; Castranova, Vincent; Demokritou, Philip; Qian, Yong

    2015-01-01

    The printer is one of the most common office equipment. Recently, it was reported that toner formulations for printing equipment constitute nano-enabled products (NEPs) and contain engineered nanomaterials (ENMs) that become airborne during printing. To date, insufficient research has been performed to understand the potential toxicological properties of printer-emitted particles (PEPs) with several studies using bulk toner particles as test particles. These studies demonstrated the ability of toner particles to cause chronic inflammation and fibrosis in animal models. However, the toxicological implications of inhalation exposures to ENMs emitted from laser printing equipment remain largely unknown. The present study investigates the toxicological effects of PEPs using an in vitro alveolar-capillary co-culture model with Human Small Airway Epithelial Cells (SAEC) and Human Microvascular Endothelial Cells (HMVEC). Our data demonstrate that direct exposure of SAEC to low concentrations of PEPs (0.5 and 1.0 µg/mL) caused morphological changes of actin remodeling and gap formations within the endothelial monolayer. Furthermore, increased production of reactive oxygen species (ROS) and angiogenesis were observed in the HMVEC. Analysis of cytokine and chemokine levels demonstrates that interleukin (IL)-6 and MCP-1 may play a major role in the cellular communication observed between SAEC and HMVEC and the resultant responses in HMVEC. These data indicate that PEPs at low, non-cytotoxic exposure levels are bioactive and affect cellular responses in an alveolar-capillary co-culture model, which raises concerns for potential adverse health effects. PMID:25387250

  16. Whole-Genome Analysis of Temporal Gene Expression during Early Transdifferentiation of Human Lung Alveolar Epithelial Type 2 Cells In Vitro

    PubMed Central

    Johansson, Helena Morales; Newman, Donna R.; Sannes, Philip L.

    2014-01-01

    It is generally accepted that the surfactant-producing pulmonary alveolar epithelial type II (AT2) cell acts as the progenitor of the type I (AT1) cell, but the regulatory mechanisms involved in this relationship remain the subject of active investigation. While previous studies have established a number of specific markers that are expressed during transdifferentiation from AT2 to AT1 cells, we hypothesized that additional, previously unrecognized, signaling pathways and relevant cellular functions are transcriptionally regulated at early stages of AT2 transition. In this study, a discovery-based gene expression profile analysis was undertaken of freshly isolated human AT2 (hAT2) cells grown on extracellular matrix (ECM) substrata known to either support (type I collagen) or retard (Matrigel) the early transdifferentiation process into hAT1-like cells over the first three days. Cell type-specific expression patterns analyzed by Illumina Human HT-12 BeadChip yielded over 300 genes that were up- or down-regulated. Candidate genes significantly induced or down-regulated during hAT2 transition to hAT1-like cells compared to non-transitioning hAT2 cells were identified. Major functional groups were also recognized, including those of signaling and cytoskeletal proteins as well as genes of unknown function. Expression of established signatures of hAT2 and hAT1 cells, such as surfactant proteins, caveolin-1, and channels and transporters, was confirmed. Selected novel genes further validated by qRT-PCR, protein expression analysis, and/or cellular localization included SPOCK2, PLEKHO1, SPRED1, RAB11FIP1, PTRF/CAVIN-1 and RAP1GAP. These results further demonstrate the utility of genome-wide analysis to identify relevant, novel cell type-specific signatures of early ECM-regulated alveolar epithelial transdifferentiation processes in vitro. PMID:24690998

  17. Mannose-capped Lipoarabinomannan from Mycobacterium tuberculosis induces IL-37 production via upregulating ERK1/2 and p38 in human type II alveolar epithelial cells.

    PubMed

    Huang, Zhen; Zhao, Gao Wei; Gao, Chun Hai; Chi, Xiu Wen; Zeng, Tao; Hu, Yan Wei; Zheng, Lei; Wang, Qian

    2015-01-01

    The major surface lipoglycan of Mycobacterium tuberculosis (M. tb), mannose-capped lipoarabinomannan (ManLAM), is an immunosuppressive epitope of M. tb. Interleukin (IL)-37, is a newly identified anti-inflammatory cytokine, which reduces systemic and local inflammation. However, the correlation between ManLAM and IL-37 remains unknown. Therefore, in this study, we investigate the possible role and relative molecular mechanism of ManLAM in IL-37 production of human type II alveolar epithelial cells by using A549 cell line. Here, we report that M. tb induced IL-37 mRNA and protein expression in a time-dependent manner. We next fractionated components of M. tb using chloroform: methanol (C:M) and water. In sharp contrast to the C:M phase, water phase was mainly responsible for the production of IL-37. Since ManLAM is the major component of water phase, we found that ManLAM induced IL-37 mRNA and protein expression in a time and dose-dependent manner, while this activity was almost totally abolished by the ERK1/2 (U0126) and p38 (SB203580) inhibitor. ManLAM stimulation significantly induced ERK1/2 and p38 phosphorylation in A549 cells, as well as cell surface TLR2 expression. After interfering TLR2 expression, ERK1/2 and p38 phosphorylation levels were markedly decreased, and also IL-37 production. Though ManLAM also promoted TLR4 expression on A549 cells, TLR4 interference showed no influence on ManLAM-induced IL-37 production. Our results indicate that ManLAM induces IL-37 production in human type II alveolar epithelial cells via up-regulating TLR2/p38 or ERK1/2 pathway, and this provide an important evidence to explain the pathological role of ManLAM that contribute to the persistence of M. tb. PMID:26221267

  18. Oncostatin M, but not interleukin-6 or leukemia inhibitory factor, stimulates expression of alpha1-proteinase inhibitor in A549 human alveolar epithelial cells.

    PubMed

    Sallenave, J M; Tremblay, G M; Gauldie, J; Richards, C D

    1997-06-01

    Alpha-1 proteinase inhibitor (A1-Pi) is the main serine proteinase inhibitor found in human plasma and is a potent elastase inhibitor in various tissues, including lung. A1-Pi is expressed and induced in liver during inflammatory responses but can also be produced by epithelial cells. Since hepatocyte A1-Pi production is stimulated by interleukin-6 (IL-6) and other gp130-cytokines, such as leukemia inhibitory factor (LIF) and oncostatin M (OM), we investigated the role of these cytokines in regulating A1-Pi in lung epithelial cells. We show that OM, a monocyte and T cell product, can specifically and potently induce A1-Pi production in lung-derived A549 alveolar (epithelial) cells, as well as in liver-derived HepG2 cells. Both A1-Pi protein (as detected by ELISA and Western blots) and mRNA levels were enhanced 20-fold to 30-fold in A549 cells. OM was also able to stimulate the expression of tissue inhibitor of metalloproteinase-1 in these cells. Interestingly, other members of the IL-6 family (IL-6 and LIF) had little or no effect on A549 cells, and proinflammatory cytokines, such as IL-1 beta and tumor necrosis factor-alpha (TNF-alpha) also had no stimulatory effect on A1-Pi synthesis in A549 cells. Costimulation with IL-1 beta resulted in a decrease in A1-Pi production from OM-stimulated A549 cells. However, IL-6 production was synergistically enhanced. OM was also able to stimulate A1-Pi production from a bronchial epithelial primary cell line, whereas an intestinal epithelial cell line HT29 responded to IL-6 but not OM. These results suggest that lung levels A1-Pi could be derived not only from liver and inflammatory cells but also from epithelial cells, which can be upregulated on stimulation by OM. This may have implications for regulation of local activity of human neutrophil elastase (HNE) in such diseases as emphysema and cystic fibrosis. PMID:9198001

  19. Periodontal repair in dogs: effect of rhBMP-2 concentration on regeneration of alveolar bone and periodontal attachment.

    PubMed

    Wikesjö, U M; Guglielmoni, P; Promsudthi, A; Cho, K S; Trombelli, L; Selvig, K A; Jin, L; Wozney, J M

    1999-06-01

    The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) concentration on regeneration of alveolar bone and cementum, and on associated root resorption and ankylosis. Contralateral, critical size, supra-alveolar, periodontal defects were surgically produced and immediately implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier in 8, young adult, male, beagle dogs. 6 animals received rhBMP-2/ACS (rhBMP-2 at 0.05, 0.10, or 0.20 mg/mL; total construct volume/defect approximately 4.0 mL) in contralateral defects following an incomplete block design. 2 animals received rhBMP-2/ACS (rhBMP-2 at 0 and 0.10 mg/mL) in contralateral defects (controls). The animals were euthanised at 8 weeks post-surgery and block sections of the defects were collected for histologic and histometric analysis. Supra-alveolar periodontal defects receiving rhBMP-2 at 0.05, 0.10, or 0.20 mg/ml exhibited extensive alveolar regeneration comprising 86%, 96%, and 88% of the defect height, respectively. Cementum regeneration encompassed 8%, 6%, and 8% of the defect height, respectively. Root resorption was observed for all rhBMP-2 concentrations. Ankylosis was observed in almost all teeth receiving rhBMP-2. Control defects without rhBMP-2 exhibited limited, if any, evidence of alveolar bone and cementum regeneration, root resorption, or ankylosis. Within the selected rhBMP-2 concentration and observation interval, there appear to be no meaningful differences in regeneration of alveolar bone and cementum. There also appear to be no significant differences in the incidence and extent of root resorption and ankylosis, though there may be a positive correlation with rhBMP-2 concentration. PMID:10382580

  20. A human esophageal epithelial cell model for study of radiation induced cancer and DNA repair

    NASA Astrophysics Data System (ADS)

    Huff, Janice; Patel, Zarana; Hada, Megumi; Cucinotta, Francis A.

    For cancer risk assessment in astronauts and for countermeasure development, it is essential to understand the molecular mechanisms of radiation carcinogenesis and how these mechanisms are influenced by exposure to the types of radiation found in space. We are developing an in vitro model system for the study of radiation-induced initiation and progression of esophageal carcinoma. Development of squamous cell carcinoma of the esophagus is associated with radiation exposure, as revealed by the significant enhanced in incidence rates for this type of cancer in the survivors of the atomic bomb detonations in Japan. It is also associated with poor nutritional status and micronutrient deficiencies, which are also important issues for long duration spaceflight. The possible synergies between nutritional issues and radiation exposure are unknown. Here we present the results of preliminary characterization of both normal and hTERT-immortalized esophageal epithelial cells grown in 2-dimensional culture. We analyzed DNA repair capacity by measuring the kinetics of formation and loss of gamma-H2AX foci following radiation exposure. Additionally, we analyzed induction of chromosomal aberrations using 3-color fluorescence in situ hybridization (FISH). Data were generated using both low LET (gamma rays) and high LET ions (1000 MeV/nucleon iron.

  1. Internalization of SiO₂ nanoparticles by alveolar macrophages and lung epithelial cells and its modulation by the lung surfactant substitute Curosurf.

    PubMed

    Vranic, Sandra; Garcia-Verdugo, Ignacio; Darnis, Cécile; Sallenave, Jean-Michel; Boggetto, Nicole; Marano, Francelyne; Boland, Sonja; Baeza-Squiban, Armelle

    2013-05-01

    Because of an increasing exposure to environmental and occupational nanoparticles (NPs), the potential risk of these materials for human health should be better assessed. Since one of the main routes of entry of NPs is via the lungs, it is of paramount importance to further characterize their impact on the respiratory system. Here, we have studied the uptake of fluorescently labeled SiO₂ NPs (50 and 100 nm) by epithelial cells (NCI-H292) and alveolar macrophages (MHS) in the presence or absence of pulmonary surfactant. The quantification of NP uptake was performed by measuring cell-associated fluorescence using flow cytometry and spectrometric techniques in order to identify the most suitable methodology. Internalization was shown to be time and dose dependent, and differences in terms of uptake were noted between epithelial cells and macrophages. In the light of our observations, we conclude that flow cytometry is a more reliable technique for the study of NP internalization, and importantly, that the hydrophobic fraction of lung surfactant is critical for downregulating NP uptake in both cell types. PMID:23288678

  2. In vitro time- and dose-effect response of JP-8 and S-8 jet fuel on alveolar type II epithelial cells of rats.

    PubMed

    Robb, Tiffany M; Rogers, Michael J; Woodward, Suann S; Wong, Simon S; Witten, Mark L

    2010-07-01

    This study was designed to characterize and compare the effects of jet propellant-8 (JP-8) fuel and synthetic-8 (S-8) on cell viability and nitric oxide synthesis in cultured alveolar type II epithelial cells of rats. Exposure times varied from 0.25, 0.5, 1, and 6 hours at the following concentrations of jet fuel: 0.0, 0.1, 0.4, and 2.0 microg/mL. Data indicate that JP-8 presents a gradual decline in cell viability and steady elevation in nitric oxide release as exposure concentrations increase. At a 2.0 microg/mL concentration of JP-8, nearly all of the cells are not viable. Moreover, S-8 exposure to rat type II lung cells demonstrated an abrupt fall in percentage cell viability and increases in nitric oxide measurement, particularly after the 2.0 microg/mL was reached at 1 and 6 hours. At 0.0, 0.2, and 0.4 microg/mL concentrations of S-8, percentage viability was sustained at steady concentrations. The results suggest different epithelial toxicity and mechanistic effects of S-8 and JP-8, providing further insight concerning the impairment imposed at specific levels of lung function and pathology induced by the different fuels. PMID:20504826

  3. N-Acetylcysteine counteracts oxidative stress and protects alveolar epithelial cells from lung contusion-induced apoptosis in rats with blunt chest trauma.

    PubMed

    Topcu-Tarladacalisir, Yeter; Tarladacalisir, Taner; Sapmaz-Metin, Melike; Karamustafaoglu, Altemur; Uz, Yesim Hulya; Akpolat, Meryem; Cerkezkayabekir, Aysegul; Turan, Fatma Nesrin

    2014-08-01

    The aim of this study was to investigate the protective effects of N-acetylcysteine (NAC) on peroxidative and apoptotic changes in the contused lungs of rats following blunt chest trauma. The rats were randomly divided into three groups: control, contusion, and contusion + NAC. All the rats, apart from those in the control group, performed moderate lung contusion. A daily intramuscular NAC injection (150 mg/kg) was given immediately following the blunt chest trauma and was continued for two additional days following cessation of the trauma. Samples of lung tissue were taken in order to evaluate the tissue malondialdehyde (MDA) level, histopathology, and epithelial cell apoptosis using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and active caspase-3 immunostaining. In addition, we immunohistochemically evaluated the expression of surfactant protein D (SP-D) in the lung tissue. The blunt chest trauma-induced lung contusion resulted in severe histopathological injury, as well as an increase in the MDA level and in the number of cells identified on TUNEL assay together with active caspase-3 positive epithelial cells, but a decrease in the number of SP-D positive alveolar type 2 (AT-2) cells. NAC treatment effectively attenuated histopathologic, peroxidative, and apoptotic changes, as well as reducing alterations in SP-D expression in the lung tissue. These findings indicate that the beneficial effects of NAC administrated following blunt chest trauma is related to the regulation of oxidative stress and apoptosis. PMID:24442604

  4. Nemo-like kinase regulates the expression of vascular endothelial growth factor (VEGF) in alveolar epithelial cells

    PubMed Central

    Ke, Hengning; Masoumi, Katarzyna Chmielarska; Ahlqvist, Kristofer; Seckl, Michael J.; Rydell-Törmänen, Kristina; Massoumi, Ramin

    2016-01-01

    The canonical Wnt signaling can be silenced either through β-catenin-mediated ubiquitination and degradation or through phosphorylation of Tcf and Lef by nemo-like kinase (NLK). In the present study, we generated NLK deficient animals and found that these mice become cyanotic shortly before death because of lung maturation defects. NLK−/− lungs exhibited smaller and compressed alveoli and the mesenchyme remained thick and hyperplastic. This phenotype was caused by epithelial activation of vascular endothelial growth factor (VEGF) via recruitment of Lef1 to the promoter of VEGF. Elevated expression of VEGF and activation of the VEGF receptor through phosphorylation promoted an increase in the proliferation rate of epithelial and endothelial cells. In summary, our study identifies NLK as a novel signaling molecule for proper lung development through the interconnection between epithelial and endothelial cells during lung morphogenesis. PMID:27035511

  5. Tumor Exosomal RNAs Promote Lung Pre-metastatic Niche Formation by Activating Alveolar Epithelial TLR3 to Recruit Neutrophils.

    PubMed

    Liu, Yanfang; Gu, Yan; Han, Yanmei; Zhang, Qian; Jiang, Zhengping; Zhang, Xiang; Huang, Bo; Xu, Xiaoqing; Zheng, Jianming; Cao, Xuetao

    2016-08-01

    The pre-metastatic niche educated by primary tumor-derived elements contributes to cancer metastasis. However, the role of host stromal cells in metastatic niche formation and organ-specific metastatic tropism is not clearly defined. Here, we demonstrate that lung epithelial cells are critical for initiating neutrophil recruitment and lung metastatic niche formation by sensing tumor exosomal RNAs via Toll-like receptor 3 (TLR3). TLR3-deficient mice show reduced lung metastasis in the spontaneous metastatic models. Mechanistically, primary tumor-derived exosomal RNAs, which are enriched in small nuclear RNAs, activate TLR3 in lung epithelial cells, consequently inducing chemokine secretion in the lung and promoting neutrophil recruitment. Identification of metastatic axis of tumor exosomal RNAs and host lung epithelial cell TLR3 activation provides potential targets to control cancer metastasis to the lung. PMID:27505671

  6. Nemo-like kinase regulates the expression of vascular endothelial growth factor (VEGF) in alveolar epithelial cells.

    PubMed

    Ke, Hengning; Masoumi, Katarzyna Chmielarska; Ahlqvist, Kristofer; Seckl, Michael J; Rydell-Törmänen, Kristina; Massoumi, Ramin

    2016-01-01

    The canonical Wnt signaling can be silenced either through β-catenin-mediated ubiquitination and degradation or through phosphorylation of Tcf and Lef by nemo-like kinase (NLK). In the present study, we generated NLK deficient animals and found that these mice become cyanotic shortly before death because of lung maturation defects. NLK-/- lungs exhibited smaller and compressed alveoli and the mesenchyme remained thick and hyperplastic. This phenotype was caused by epithelial activation of vascular endothelial growth factor (VEGF) via recruitment of Lef1 to the promoter of VEGF. Elevated expression of VEGF and activation of the VEGF receptor through phosphorylation promoted an increase in the proliferation rate of epithelial and endothelial cells. In summary, our study identifies NLK as a novel signaling molecule for proper lung development through the interconnection between epithelial and endothelial cells during lung morphogenesis. PMID:27035511

  7. Recruited alveolar macrophages, in response to airway epithelial-derived monocyte chemoattractant protein 1/CCl2, regulate airway inflammation and remodeling in allergic asthma.

    PubMed

    Lee, Yong Gyu; Jeong, Jong Jin; Nyenhuis, Sharmilee; Berdyshev, Evgeny; Chung, Sangwoon; Ranjan, Ravi; Karpurapu, Manjula; Deng, Jing; Qian, Feng; Kelly, Elizabeth A B; Jarjour, Nizar N; Ackerman, Steven J; Natarajan, Viswanathan; Christman, John W; Park, Gye Young

    2015-06-01

    Although alveolar macrophages (AMs) from patients with asthma are known to be functionally different from those of healthy individuals, the mechanism by which this transformation occurs has not been fully elucidated in asthma. The goal of this study was to define the mechanisms that control AM phenotypic and functional transformation in response to acute allergic airway inflammation. The phenotype and functional characteristics of AMs obtained from human subjects with asthma after subsegmental bronchoprovocation with allergen was studied. Using macrophage-depleted mice, the role and trafficking of AM populations was determined using an acute allergic lung inflammation model. We observed that depletion of AMs in a mouse allergic asthma model attenuates Th2-type allergic lung inflammation and its consequent airway remodeling. In both human and mouse, endobronchial challenge with allergen induced a marked increase in monocyte chemotactic proteins (MCPs) in bronchoalveolar fluid, concomitant with the rapid appearance of a monocyte-derived population of AMs. Furthermore, airway allergen challenge of allergic subjects with mild asthma skewed the pattern of AM gene expression toward high levels of the receptor for MCP1 (CCR2/MCP1R) and expression of M2 phenotypic proteins, whereas most proinflammatory genes were highly suppressed. CCL2/MCP-1 gene expression was prominent in bronchial epithelial cells in a mouse allergic asthma model, and in vitro studies indicate that bronchial epithelial cells produced abundant MCP-1 in response to house dust mite allergen. Thus, our study indicates that bronchial allergen challenge induces the recruitment of blood monocytes along a chemotactic gradient generated by allergen-exposed bronchial epithelial cells. PMID:25360868

  8. Epithelial Sodium Channels in Pulmonary Epithelial Progenitor and Stem Cells

    PubMed Central

    Liu, Yang; Jiang, Bi-Jie; Zhao, Run-Zhen; Ji, Hong-Long

    2016-01-01

    Regeneration of the epithelium of mammalian lungs is essential for restoring normal function following injury, and various cells and mechanisms contribute to this regeneration and repair. Club cells, bronchioalveolar stem cells (BASCs), and alveolar type II epithelial cells (ATII) are dominant stem/progenitor cells for maintaining epithelial turnover and repair. Epithelial Na+ channels (ENaC), a critical pathway for transapical salt and fluid transport, are expressed in lung epithelial progenitors, including club and ATII cells. Since ENaC activity and expression are development- and differentiation-dependent, apically located ENaC activity has therefore been used as a functional biomarker of lung injury repair. ENaC activity may be involved in the migration and differentiation of local and circulating stem/progenitor cells with diverse functions, eventually benefiting stem cells spreading to re-epithelialize injured lungs. This review summarizes the potential roles of ENaC expressed in native progenitor and stem cells in the development and regeneration of the respiratory epithelium. PMID:27570489

  9. High-mobility group box 1 promotes extracellular matrix synthesis and wound repair in human bronchial epithelial cells.

    PubMed

    Ojo, Oluwaseun O; Ryu, Min Hyung; Jha, Aruni; Unruh, Helmut; Halayko, Andrew J

    2015-12-01

    High mobility group box 1 (HMGB1) is a damage-associated molecular pattern (DAMP) protein that binds Toll-like receptors (e.g., TLR4) and the receptor for advanced glycated end products (RAGE). The direct effects of HMGB1 on airway structural cells are not fully known. As epithelial cell responses are fundamental drivers of asthma, including abnormal repair-restitution linked to changes in extracellular matrix (ECM) synthesis, we tested the hypothesis that HMGB1 promotes bronchial epithelial cell wound repair via TLR4 and/or RAGE signaling that regulates ECM (fibronectin and the γ2-chain of laminin-5) and integrin protein abundance. To assess impact of HMGB1 we used molecular and pharmacological inhibitors of RAGE or TLR4 signaling in scratch wound, immunofluorescence, and immunoblotting assays to assess wound repair, ECM synthesis, and phosphorylation of intracellular signaling. HMGB1 increased wound closure, and this effect was attenuated by blocking RAGE and TLR4 signaling. HMGB1-induced fibronectin and laminin-5 (γ2 chain) was diminished by blocking RAGE and/or blunting TLR4 signaling. Similarly, induction of α3-integrin receptor for fibronectin and laminin-5 was also diminished by blocking TLR4 signaling and RAGE. Lastly, rapid and/or sustained phosphorylation of SMAD2, ERK1/2, and JNK signaling modulated HMGB1-induced wound closure. Our findings suggest a role for HMGB1 in human airway epithelial cell repair and restitution via multiple pathways mediated by TLR4 and RAGE that underpin increased ECM synthesis and modulation of cell-matrix adhesion. PMID:26432865

  10. Hyperoxia-mediated LC3B activation contributes to the impaired transdifferentiation of type II alveolar epithelial cells (AECIIs) to type I cells (AECIs).

    PubMed

    Zhang, Liang; Zhao, Shuang; Yuan, Lijie; Wu, Hongmin; Jiang, Hong; Luo, Gang

    2016-09-01

    Life-saving mechanical ventilation can also cause lung injury through the overproduction of reactive oxygen species (ROS), leading to bronchopulmonary dysplasia (BPD)-like symptoms in preterm infants. It is reported that the autophagic protein microtubule-associated protein-1 light chain (LC)-3B can confer protection against hyperoxia-induced DNA damage in lung alveolar epithelium. However, its role in the transdifferentiation of type II alveolar epithelial cells (AECIIs) to type I cells (AECIs) is unclear and requires further investigation. In this study, newborn Sprague-Dawley rats were exposed to 90% oxygen for up to 14 days to mimic BPD in human infants, with neonatal pups exposed to room air (21% oxygen) as controls. Primary rat AECIIs were cultured under hyperoxic conditions for up to 24 hours to further investigate the underlying mechanisms. This study found that hyperoxia promoted a significant and time-dependent increase of AECII marker surfactant protein (SP)-C in the lung. The increase of AECI marker T1α was repressed by hyperoxia during lung development. These results indicated an impaired AECII transdifferentiation. Pulmonary ROS concentration and expression of autophagic protein LC-3B were increased gradually in response to hyperoxia exposure. Furthermore, AECIIs produced more ROS when cultured under hyperoxic conditions in vitro. Both the LC3B expression and the conversion from LC3BI to LC3BII were enhanced in hyperoxic AECs. Interestingly, inhibition of LC3B either by ROS inhibitor N-acetyl-l-cysteine (NAC) or adenovirus-mediated LC3B shRNA could partly restore AECII transdifferentiation under hyperoxia condition. In summary, the current study reveals a novel role of activated LC3B induced by hyperoxia in AECII transdifferentiation. PMID:27187184

  11. Lipoxin A4 activates alveolar epithelial sodium channel gamma via the microRNA-21/PTEN/AKT pathway in lipopolysaccharide-induced inflammatory lung injury.

    PubMed

    Qi, Wei; Li, Hui; Cai, Xiao-Hong; Gu, Jia-Qi; Meng, Jin; Xie, Hai-Qing; Zhang, Jun-Li; Chen, Jie; Jin, Xian-Guan; Tang, Qian; Hao, Yu; Gao, Ye; Wen, Ai-Qing; Xue, Xiang-Yang; Gao Smith, Fang; Jin, Sheng-Wei

    2015-11-01

    Lipoxin A4 (LXA4), as an endogenously produced lipid mediator, promotes the resolution of inflammation. Previously, we demonstrated that LXA4 stimulated alveolar fluid clearance through alveolar epithelial sodium channel gamma (ENaC-γ). In this study, we sought to investigate the mechanisms of LXA4 in modulation of ENaC-γ in lipopolysaccharide (LPS)-induced inflammatory lung injury. miR-21 was upregulated during an LPS challenge and downregulated by LXA4 administration in vivo and in vitro. Serum miR-21 concentration was also elevated in acute respiratory distress syndrome patients as compared with healthy volunteers. LPS increased miR-21 expression by activation of activator protein 1 (AP-1). In A549 cells, miR-21 upregulated phosphorylation of AKT activation via inhibition of phosphatase and tensin homolog (PTEN), and therefore reduced the expression of ENaC-γ. In contrast, LXA4 reversed LPS-inhibited ENaC-γ expression through inhibition of AP-1 and activation of PTEN. In addition, an miR-21 inhibitor mimicked the effects of LXA4; overexpression of miR-21 abolished the protective effects of LXA4. Finally, both AKT and ERK inhibitors (LY294002 and UO126) blocked effects of LPS on the depression of ENaC-γ. However, LXA4 only inhibited LPS-induced phosphorylation of AKT. In summary, LXA4 activates ENaC-γ in part via the miR-21/PTEN/AKT signaling pathway. PMID:26302186

  12. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air-liquid interface

    SciTech Connect

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2015-02-01

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specific fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. Together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.

  13. Evaluation of pulmonary alveolar epithelial integrity by the detection of restriction to diffusion of hydrophilic solutes of different molecular sizes.

    PubMed

    Mason, G R; Peters, A M; Bagdades, E; Myers, M J; Snook, D; Hughes, J M

    2001-03-01

    The rate of transfer of a hydrophilic solute from the alveoli to pulmonary blood following inhalation as an aerosol depends on the molecular size of the solute and the permeability of the alveolar epithelium. The value of this measurement for assessing damage to the epithelium in lung disease is compromised by cigarette smoking, which accelerates clearance by unknown mechanisms. The rates of clearance of (99m)Tc-labelled diethylenetriaminepenta-acetic acid (DTPA) (molecular mass 492 Da) and (113m)In-labelled biotinylated DTPA (B-DTPA) (molecular mass 1215 Da) were monitored simultaneously by dynamic gamma-radiation camera imaging following simultaneous inhalation, and compared between eight normal non-smoking subjects and nine habitual cigarette smokers. The clearance rates of DTPA were 0.95 (S.D. 0.39)%/min in non-smokers and 4.13 (1.06) %/min in smokers. These were about twice the clearance rates of B-DTPA, which in the corresponding groups were 0.41 (0.26) and 2.12 (0.72)%/min respectively. The ratio of the B-DTPA/DTPA clearance rates was, in all subjects, less than the ratio (0.74) of the cube roots of the molecular masses of the solutes, assumed to correspond to the ratio of their free diffusion coefficients in water, and was not significantly different between smokers and non-smokers. As alveolar permeability increased, the ratio of clearance rates in the entire population showed a significant trend to increase in a non-linear fashion towards the value corresponding to the ratio of the free diffusion coefficients. We conclude that the diffusion of at least the larger of these two solutes through the pulmonary alveolar epithelium is restricted (i.e. associated with a reflection coefficient greater than zero). Cigarette smoking, however, does not appear to cause a loss of this restriction, and may increase solute clearance by other mechanisms, such as reducing fluid volume within the alveolus, thereby raising the local radiotracer concentration, or increasing

  14. DA-Raf-Mediated Suppression of the Ras--ERK Pathway Is Essential for TGF-β1-Induced Epithelial-Mesenchymal Transition in Alveolar Epithelial Type 2 Cells.

    PubMed

    Watanabe-Takano, Haruko; Takano, Kazunori; Hatano, Masahiko; Tokuhisa, Takeshi; Endo, Takeshi

    2015-01-01

    Myofibroblasts play critical roles in the development of idiopathic pulmonary fibrosis by depositing components of extracellular matrix. One source of lung myofibroblasts is thought to be alveolar epithelial type 2 cells that undergo epithelial-mesenchymal transition (EMT). Rat RLE-6TN alveolar epithelial type 2 cells treated with transforming growth factor-β1 (TGF-β1) are converted into myofibroblasts through EMT. TGF-β induces both canonical Smad signaling and non-canonical signaling, including the Ras-induced ERK pathway (Raf-MEK-ERK). However, the signaling mechanisms regulating TGF-β1-induced EMT are not fully understood. Here, we show that the Ras-ERK pathway negatively regulates TGF-β1-induced EMT in RLE-6TN cells and that DA-Raf1 (DA-Raf), a splicing isoform of A-Raf and a dominant-negative antagonist of the Ras-ERK pathway, plays an essential role in EMT. Stimulation of the cells with fibroblast growth factor 2 (FGF2), which activated the ERK pathway, prominently suppressed TGF-β1-induced EMT. An inhibitor of MEK, but not an inhibitor of phosphatidylinositol 3-kinase, rescued the TGF-β1-treated cells from the suppression of EMT by FGF2. Overexpression of a constitutively active mutant of a component of the Ras-ERK pathway, i.e., H-Ras, B-Raf, or MEK1, interfered with EMT. Knockdown of DA-Raf expression with siRNAs facilitated the activity of MEK and ERK, which were only weakly and transiently activated by TGF-β1. Although DA-Raf knockdown abrogated TGF-β1-induced EMT, the abrogation of EMT was reversed by the addition of the MEK inhibitor. Furthermore, DA-Raf knockdown impaired the TGF-β1-induced nuclear translocation of Smad2, which mediates the transcription required for EMT. These results imply that intrinsic DA-Raf exerts essential functions for EMT by antagonizing the TGF-β1-induced Ras-ERK pathway in RLE-6TN cells. PMID:25996975

  15. Canonical pathways, networks and transcriptional factor regulation by clinical strains of Mycobacterium tuberculosis in pulmonary alveolar epithelial cells.

    PubMed

    Mvubu, Nontobeko E; Pillay, Balakrishna; Gamieldien, Junaid; Bishai, William; Pillay, Manormoney

    2016-03-01

    Limited knowledge exists on pathways, networks and transcriptional factors regulated within epithelial cells by diverse Mycobacterium tuberculosis genotypes. This study aimed to elucidate these mechanisms induced in A549 epithelial cells by dominant clinical strains in KwaZulu-Natal, South Africa. RNA for sequencing was extracted from epithelial cells at 48 h post-infection with 5 strains at a multiplicity of infection of approximately 10:1. Bioinformatics analysis performed with the RNA-Seq Tuxedo pipeline identified differentially expressed genes. Changes in pathways, networks and transcriptional factors were identified using Ingenuity Pathway Analysis (IPA). The interferon signalling and hepatic fibrosis/hepatic stellate cell activation pathways were among the top 5 canonical pathways in all strains. Hierarchical clustering for enrichment of cholesterol biosynthesis and immune associated pathways revealed similar patterns for Beijing and Unique; F15/LAM4/KZN and F11; and, F28 and H37Rv strains, respectively. However, the induction of top scoring networks varied among the strains. Among the transcriptional factors, only EHL, IRF7, PML, STAT1, STAT2 and VDR were induced by all clinical strains. Activation of the different pathways, networks and transcriptional factors revealed in the current study may be an underlying mechanism that results in the differential host response by clinical strains of M. tuberculosis. PMID:26980499

  16. Erratum: Mannose-capped lipoarabinomannan from Mycobacterium tuberculosis induces IL-37 production via upregulating ERK1/2 and p38 in human type II alveolar epithelial cells.

    PubMed

    Huang, Zhen; Zhao, Gao Wei; Gao, Chun Hai; Chi, Xiu Wen; Zeng, Tao; Hu, Yan Wei; Zheng, Lei; Wang, Qian

    2015-01-01

    The major surface lipoglycan of Mycobacterium tuberculosis (M. tb), mannose-capped lipoarabinomannan (ManLAM), is an immunosuppressive epitope of M. tb. Interleukin (IL)-37, is a newly identified anti-inflammatory cytokine, which reduces systemic and local inflammation. However, the correlation between ManLAM and IL-37 remains unknown. Therefore, in this study, we investigate the possible role and relative molecular mechanism of ManLAM in IL-37 production of human type II alveolar epithelial cells by using A549 cell line. Here, we report that M. tb induced IL-37 mRNA and protein expression in a time-dependent manner. We next fractionated components of M. tb using chloroform: methanol (C:M) and water. In sharp contrast to the C:M phase, water phase was mainly responsible for the production of IL-37. Since ManLAM is the major component of water phase, we found that ManLAM induced IL-37 mRNA and protein expression in a time and dose-dependent manner, while this activity was almost totally abolished by the ERK1/2 (U0126) and p38 (SB203580) inhibitor. ManLAM stimulation significantly induced ERK1/2 and p38 phosphorylation in A549 cells, as well as cell surface TLR2 expression. After interfering TLR2 expression, ERK1/2 and p38 phosphorylation levels were markedly decreased, and also IL-37 production. Though ManLAM also promoted TLR4 expression on A549 cells, TLR4 interference showed no influence on ManLAM-induced IL-37 production. Our results indicate that ManLAM induces IL-37 production in human type II alveolar epithelial cells via up-regulating TLR2/p38 or ERK1/2 pathway, and this provide an important evidence to explain the pathological role of ManLAM that contribute to the persistence of M. tb.[This corrects the article on p. 7279 in vol. 8, PMID: 26221267.]. PMID:26770645

  17. Midgut epithelial responses of different mosquito–Plasmodium combinations: The actin cone zipper repair mechanism in Aedes aegypti

    PubMed Central

    Gupta, Lalita; Kumar, Sanjeev; Han, Yeon Soo; Pimenta, Paulo F. P.; Barillas-Mury, Carolina

    2005-01-01

    In vivo responses of midgut epithelial cells to ookinete invasion of three different vector–parasite combinations, Aedes aegypti–Plasmodium gallinaceum, Anopheles stephensi–Plasmodium berghei, and A. stephensi–P. gallinaceum, were directly compared by using enzymatic markers and immunofluorescence stainings. Our studies indicate that, in A. aegypti and A. stephensi ookinetes traverse the midgut via an intracellular route and inflict irreversible damage to the invaded cells. These two mosquito species differ, however, in their mechanisms of epithelial repair. A. stephensi detaches damaged cells by an actin-mediated budding-off mechanism when invaded by either P. berghei or P. gallinaceum. In A. aegypti, the midgut epithelium is repaired by a unique actin cone zipper mechanism that involves the formation of a cone-shaped actin aggregate at the base of the cell that closes sequentially, expelling the cellular contents into the midgut lumen as it brings together healthy neighboring cells. Invasion of A. stephensi by P. berghei induced expression of nitric oxide synthase and peroxidase activities, which mediate tyrosine nitration. These enzymes and nitrotyrosine, however, were not induced in the other two vector–parasite combinations examined. These studies indicate that the epithelial responses of different mosquito–parasite combinations are not universal. The implications of these observations to validate animal experimental systems that reflect the biology of natural vectors of human malarias are discussed. PMID:15753303

  18. Midgut epithelial responses of different mosquito-Plasmodium combinations: the actin cone zipper repair mechanism in Aedes aegypti.

    PubMed

    Gupta, Lalita; Kumar, Sanjeev; Han, Yeon Soo; Pimenta, Paulo F P; Barillas-Mury, Carolina

    2005-03-15

    In vivo responses of midgut epithelial cells to ookinete invasion of three different vector-parasite combinations, Aedes aegypti-Plasmodium gallinaceum, Anopheles stephensi-Plasmodium berghei, and A. stephensi-P. gallinaceum, were directly compared by using enzymatic markers and immunofluorescence stainings. Our studies indicate that, in A. aegypti and A. stephensi ookinetes traverse the midgut via an intracellular route and inflict irreversible damage to the invaded cells. These two mosquito species differ, however, in their mechanisms of epithelial repair. A. stephensi detaches damaged cells by an actin-mediated budding-off mechanism when invaded by either P. berghei or P. gallinaceum. In A. aegypti, the midgut epithelium is repaired by a unique actin cone zipper mechanism that involves the formation of a cone-shaped actin aggregate at the base of the cell that closes sequentially, expelling the cellular contents into the midgut lumen as it brings together healthy neighboring cells. Invasion of A. stephensi by P. berghei induced expression of nitric oxide synthase and peroxidase activities, which mediate tyrosine nitration. These enzymes and nitrotyrosine, however, were not induced in the other two vector-parasite combinations examined. These studies indicate that the epithelial responses of different mosquito-parasite combinations are not universal. The implications of these observations to validate animal experimental systems that reflect the biology of natural vectors of human malarias are discussed. PMID:15753303

  19. Epithelial to mesenchymal transition (EMT) induced by bleomycin or TFG(b1)/EGF in murine induced pluripotent stem cell-derived alveolar Type II-like cells.

    PubMed

    Alipio, Zaida A; Jones, Nathan; Liao, Wenbin; Yang, Jianchang; Kulkarni, Shilpa; Sree Kumar, K; Hauer-Jensen, Martin; Ward, David C; Ma, Yupo; Fink, Louis M

    2011-09-01

    Induced pluripotent stem (iPS) cells are derived from reprogrammed somatic cells and are similar to embryonic stem (ES) cells in morphology, gene/protein expression, and pluripotency. In this study, we explored the potential of iPS cells to differentiate into alveolar Type II (ATII)-like epithelial cells. Analysis using quantitative real time polymerase chain reaction and immunofluorescence staining showed that pulmonary surfactant proteins commonly expressed by ATII cells such as surfactant protein A (SPA), surfactant protein B (SPB), and surfactant protein C (SPC) were upregulated in the differentiated cells. Microphilopodia characteristics and lamellar bodies were observed by transmission electron microscopy and lipid deposits were verified by Nile Red and Periodic Acid Schiff staining. C3 complement protein, a specific feature of ATII cells, was present at high levels in culture supernatants demonstrating functionality of these cells in culture. These data show that the differentiated cells generated from iPS cells using a culture method developed previously (Rippon et al., 2006) are ATII-like cells. To further characterize these ATII-like cells, we tested whether they could undergo epithelial to mesenchymal transition (EMT) by exposure to drugs that induce lung fibrosis in mice, such as bleomycin, and the combination of transforming growth factor beta1 (TGF(b1)) and epidermal growth factor (EGF). When the ATII-like cells were exposed to either bleomycin or a TGF(b1)-EGF cocktail, they underwent phenotypic changes including acquisition of a mesenchymal/fibroblastic morphology, upregulation of mesenchymal markers (Col1, Vim, a-Sma, and S100A4), and downregulation of surfactant proteins and E-cadherin. We have shown that ATII-like cells can be derived from skin fibroblasts and that they respond to fibrotic stimuli. These cells provide a valuable tool for screening of agents that can potentially ameliorate or prevent diseases involving lung fibrosis. PMID:21596473

  20. Wnt3a mitigates acute lung injury by reducing P2X7 receptor-mediated alveolar epithelial type I cell death

    PubMed Central

    Guo, Y; Mishra, A; Weng, T; Chintagari, N R; Wang, Y; Zhao, C; Huang, C; Liu, L

    2014-01-01

    Acute lung injury (ALI) is characterized by pulmonary endothelial and epithelial cell damage, and loss of the alveolar–capillary barrier. We have previously shown that P2X7 receptor (P2X7R), a cell death receptor, is specifically expressed in alveolar epithelial type I cells (AEC I). In this study, we hypothesized that P2X7R-mediated purinergic signaling and its interaction with Wnt/β-catenin signaling contributes to AEC I death. We examined the effect of P2X7R agonist 2′-3′-O-(4-benzoylbenzoyl)-ATP (BzATP) and Wnt agonist Wnt3a on AEC I death in vitro and in vivo. We also assessed the therapeutic potential of Wnt3a in a clinically relevant ALI model of intratracheal lipopolysaccharide (LPS) exposure in ventilated mice. We found that the activation of P2X7R by BzATP caused the death of AEC I by suppressing Wnt/β-catenin signaling through stimulating glycogen synthase kinase-3β (GSK-3β) and proteasome. On the other hand, the activation of Wnt/β-catenin signaling by Wnt3a, GSK-3β inhibitor, or proteasome inhibitor blocked the P2X7R-mediated cell death. More importantly, Wnt3a attenuated the AEC I damage caused by intratracheal instillation of BzATP in rats or LPS in ventilated mice. Our results suggest that Wnt3a overrides the effect of P2X7R on the Wnt/β-catenin signaling to prevent the AEC I death and restrict the severity of ALI. PMID:24922070

  1. miR-34 miRNAs Regulate Cellular Senescence in Type II Alveolar Epithelial Cells of Patients with Idiopathic Pulmonary Fibrosis

    PubMed Central

    Disayabutr, Supparerk; Kim, Eun Kyung; Cha, Seung-Ick; Green, Gary; Naikawadi, Ram P.; Jones, Kirk D.; Golden, Jeffrey A.; Schroeder, Aaron; Matthay, Michael A.; Kukreja, Jasleen; Erle, David J.; Collard, Harold R.; Wolters, Paul J.

    2016-01-01

    Pathologic features of idiopathic pulmonary fibrosis (IPF) include genetic predisposition, activation of the unfolded protein response, telomere attrition, and cellular senescence. The mechanisms leading to alveolar epithelial cell (AEC) senescence are poorly understood. MicroRNAs (miRNAs) have been reported as regulators of cellular senescence. Senescence markers including p16, p21, p53, and senescence-associated β-galactosidase (SA-βgal) activity were measured in type II AECs from IPF lungs and unused donor lungs. miRNAs were quantified in type II AECs using gene expression arrays and quantitative RT-PCR. Molecular markers of senescence (p16, p21, and p53) were elevated in IPF type II AECs. SA-βgal activity was detected in a greater percentage in type II AECs isolated from IPF patients (23.1%) compared to patients with other interstitial lung diseases (1.2%) or normal controls (0.8%). The relative levels of senescence-associated miRNAs miR-34a, miR-34b, and miR-34c, but not miR-20a, miR-29c, or miR-let-7f were significantly higher in type II AECs from IPF patients. Overexpression of miR-34a, miR-34b, or miR-34c in lung epithelial cells was associated with higher SA-βgal activity (27.8%, 35.1%, and 38.2%, respectively) relative to control treated cells (8.8%). Targets of miR-34 miRNAs, including E2F1, c-Myc, and cyclin E2, were lower in IPF type II AECs. These results show that markers of senescence are uniquely elevated in IPF type II AECs and suggest that the miR-34 family of miRNAs regulate senescence in IPF type II AECs. PMID:27362652

  2. Evaluation of Pseudomonas aeruginosa (PAO1) adhesion to human alveolar epithelial cells A549 using SYTO 9 dye.

    PubMed

    Larrosa, Mar; Truchado, Pilar; Espín, Juan Carlos; Tomás-Barberán, Francisco A; Allende, Ana; García-Conesa, María Teresa

    2012-06-01

    Pseudomonas aeruginosa is an aerobic Gram-negative bacterium characterized by a natural resistance to several antibiotics. It is a major cause of nosocomial infections in patients with compromised host defence mechanisms mainly related to the respiratory tract. P. aeruginosa infection first step is the adhesion of the bacteria to the host cells and thus, the development of techniques that can easily assess adhesion of bacteria strains and of bacteria isolated from biological samples is fundamental. The aim of our work was to develop a fast and effective method to evaluate the adhesion of P. aeruginosa to bronchial epithelial cells. To meet our goal we optimized a staining protocol using the vital dye SYTO 9 and P. aeruginosa PAO1. We established the appropriate dying conditions as well as the stability of the stained bacteria. Adhesion was first measured using the traditional plate counting method and then, adhesion values were compared to those obtained using a fluorescence microplate reader and epifluorescence microscopy. Our results show that the use of SYTO 9 does not interfere with the bacteria viability, bacteria cell growth, and adhesion of P. aeruginosa to A549 epithelial cells. Both the fluorescence microplate reader and the epifluorescence microscopy gave similar results to those attained with the plate counting method, however, the epifluorescence microscopy also allowed for simultaneous discrimination of damaging effects on the human cells. Overall, our data indicate that the use of SYTO 9 combined with a fluorescence microplate reader or an epifluorescence microscope provides a rapid method to evaluate the adhesion of P. aeruginosa to human epithelial cells. However, to show unequivocally that a specific drug or compound has a truly inhibitory effect on the bacterial adhesion without affecting the number of human cells, the epifluorescence microscopy is recommended. PMID:22464926

  3. Human amniotic epithelial cell transplantation for the repair of injured brachial plexus nerve: evaluation of nerve viscoelastic properties

    PubMed Central

    Jin, Hua; Yang, Qi; Ji, Feng; Zhang, Ya-jie; Zhao, Yan; Luo, Min

    2015-01-01

    The transplantation of embryonic stem cells can effectively improve the creeping strength of nerves near an injury site in animals. Amniotic epithelial cells have similar biological properties as embryonic stem cells; therefore, we hypothesized that transplantation of amniotic epithelial cells can repair peripheral nerve injury and recover the creeping strength of the brachial plexus nerve. In the present study, a brachial plexus injury model was established in rabbits using the C6 root avulsion method. A suspension of human amniotic epithelial cells was repeatedly injected over an area 4.0 mm lateral to the cephal and caudal ends of the C6 brachial plexus injury site (1 × 106 cells/mL, 3 μL/injection, 25 injections) immediately after the injury. The results showed that the decrease in stress and increase in strain at 7,200 seconds in the injured rabbit C6 brachial plexus nerve were mitigated by the cell transplantation, restoring the viscoelastic stress relaxation and creep properties of the brachial plexus nerve. The forepaw functions were also significantly improved at 26 weeks after injury. These data indicate that transplantation of human amniotic epithelial cells can effectively restore the mechanical properties of the brachial plexus nerve after injury in rabbits and that viscoelasticity may be an important index for the evaluation of brachial plexus injury in animals. PMID:25883625

  4. Anacardic acid, a histone acetyltransferase inhibitor, modulates LPS-induced IL-8 expression in a human alveolar epithelial cell line A549

    PubMed Central

    Takizawa, Hajime

    2013-01-01

    Objective and design: The histone acetylation processes, which are believed to play a critical role in the regulation of many inflammatory genes, are reversible and regulated by histone acetyltransferases (HATs), which promote acetylation, and histone deacetylases (HDACs), which promote deacetylation. We studied the effects of lipopolysaccharide (LPS) on histone acetylation and its role in the regulation of interleukin (IL)-8 expression.  Material: A human alveolar epithelial cell line A549 was used in vitro. Methods: Histone H4 acetylation at the IL-8 promoter region was assessed by a chromatin immunoprecipitation (ChIP) assay. The expression and production of IL-8 were evaluated by quantitative polymerase chain reaction and specific immunoassay. Effects of a HDAC inhibitor, trichostatin A (TSA), and a HAT inhibitor, anacardic acid, were assessed.  Results: Escherichia coli-derived LPS showed a dose- and time-dependent stimulatory effect on IL-8 protein production and mRNA expression in A549 cells in vitro. LPS showed a significant stimulatory effect on histone H4 acetylation at the IL-8 promoter region by ChIP assay. Pretreatment with TSA showed a dose-dependent stimulatory effect on IL-8 release from A549 cells as compared to LPS alone. Conversely, pretreatment with anacardic acid inhibited IL-8 production and expression in A549 cells.  Conclusion: These data suggest that LPS-mediated proinflammatory responses in the lungs might be modulated via changing chromatin remodeling by HAT inhibition. PMID:24627774

  5. Astaxanthin inhibits apoptosis in alveolar epithelial cells type II in vivo and in vitro through the ROS-dependent mitochondrial signalling pathway

    PubMed Central

    Song, Xiaodong; Wang, Bingsi; Lin, Shengcui; Jing, Lili; Mao, Cuiping; Xu, Pan; Lv, Changjun; Liu, Wen; Zuo, Ji

    2014-01-01

    Oxidative stress is an important molecular mechanism underlying lung fibrosis. The mitochondrion is a major organelle for oxidative stress in cells. Therefore, blocking the mitochondrial signalling pathway may be the best therapeutic manoeuver to ameliorate lung fibrosis. Astaxanthin (AST) is an excellent antioxidant, but no study has addressed the pathway of AST against pulmonary oxidative stress and free radicals by the mitochondrion-mediated signalling pathway. In this study, we investigated the antioxidative effects of AST against H2O2- or bleomycin (BLM)-induced mitochondrial dysfunction and reactive oxygen species (ROS) production in alveolar epithelial cells type II (AECs-II) in vivo and in vitro. Our data show that AST blocks H2O2- or BLM-induced ROS generation and dose-dependent apoptosis in AECs-II, as characterized by changes in cell and mitochondria morphology, translocation of apoptotic proteins, inhibition of cytochrome c (Cyt c) release, and the activation of caspase-9, caspase-3, Nrf-2 and other cytoprotective genes. These data suggest that AST inhibits apoptosis in AECs-II cells through the ROS-dependent mitochondrial signalling pathway and may be of potential therapeutic value in lung fibrosis treatment. PMID:25215580

  6. Alveolar Type II Epithelial Cells Contribute to the Anti-Influenza A Virus Response in the Lung by Integrating Pathogen- and Microenvironment-Derived Signals

    PubMed Central

    Jeron, Andreas; Gereke, Marcus; Geffers, Robert; Kröger, Andrea; Gunzer, Matthias; Bruder, Dunja

    2016-01-01

    ABSTRACT Influenza A virus (IAV) periodically causes substantial morbidity and mortality in the human population. In the lower lung, the primary targets for IAV replication are type II alveolar epithelial cells (AECII), which are increasingly recognized for their immunological potential. So far, little is known about their reaction to IAV and their contribution to respiratory antiviral immunity in vivo. Therefore, we characterized the AECII response during early IAV infection by analyzing transcriptional regulation in cells sorted from the lungs of infected mice. We detected rapid and extensive regulation of gene expression in AECII following in vivo IAV infection. The comparison to transcriptional regulation in lung tissue revealed a strong contribution of AECII to the respiratory response. IAV infection triggered the expression of a plethora of antiviral factors and immune mediators in AECII with a high prevalence for interferon-stimulated genes. Functional pathway analyses revealed high activity in pathogen recognition, immune cell recruitment, and antigen presentation. Ultimately, our analyses of transcriptional regulation in AECII and lung tissue as well as interferon I/III levels and cell recruitment indicated AECII to integrate signals provided by direct pathogen recognition and surrounding cells. Ex vivo analysis of AECII proved a powerful tool to increase our understanding of their role in respiratory immune responses, and our results clearly show that AECII need to be considered a part of the surveillance and effector system of the lower respiratory tract. PMID:27143386

  7. Tropomyosin-1 protects transformed alveolar epithelial cells against cigaret smoke extract through the stabilization of F-actin-dependent cell-cell junctions.

    PubMed

    Gagat, Maciej; Grzanka, Dariusz; Izdebska, Magdalena; Sroka, Wiktor Dariusz; Hałas-Wiśniewska, Marta; Grzanka, Alina

    2016-04-01

    The aim of the study was to estimate the effect of tropomyosin-1-based structural stabilization of F-actin in transformed human alveolar epithelial line H1299 cells subjected to high oxidative stress induced by cigaret smoke extract. We demonstrated here that cigaret smoke extract induces cell shrinking and detachment as a consequence of F-actin cytoskeleton degradation in H1299 cells not overexpressing tropomyosin-1. Furthermore, the treatment of these cells with cigaret smoke extract resulted in the loss of peripheral localization of ZO-1 and initiated apoptosis. In contrast, structural stabilization of F-actin, by overexpression of tropomyosin-1, preserved cell to cell interactions through the attenuation of cortical actin organization into thin fibers and thus protected these cells against oxidative stress-induced degradation of actin cytoskeleton and cell death. In conclusion, we suggest that structural stabilization of thin cortical F-actin fibers increases link between tight junctions proteins and actin cytoskeleton and thus protects H1299 cells against cigaret smoke extract. PMID:26805581

  8. N-acetylcysteine amide, a thiol antioxidant, prevents bleomycin-induced toxicity in human alveolar basal epithelial cells (A549).

    PubMed

    Tobwala, S; Fan, W; Stoeger, T; Ercal, N

    2013-09-01

    Bleomycin (BLM), a glycopeptide antibiotic from Streptomyces verticillus, is an effective antineoplastic drug. However, its clinical use is restricted due to the wide range of associated toxicities, especially pulmonary toxicity. Oxidative stress has been implicated as an important factor in the development of BLM-induced pulmonary toxicity. Previous studies have indicated disruption of thiol-redox status in lungs (lung epithelial cells) upon BLM treatment. Therefore, this study focused on (1) investigating the oxidative effects of BLM on lung epithelial cells (A549) and (2) elucidating whether a well-known thiol antioxidant, N-acetylcysteine amide (NACA), provides any protection against BLM-induced toxicity. Oxidative stress parameters, such as glutathione (GSH), malondialdehyde (MDA), and antioxidant enzyme activities were altered upon BLM treatment. Loss of mitochondrial membrane potential (ΔΨm), as assessed by fluorescence microscopy, indicated that cytotoxicity is possibly mediated through mitochondrial dysfunction. Pretreatment with NACA reversed the oxidative effects of BLM. NACA decreased the reactive oxygen species (ROS) and MDA levels and restored the intracellular GSH levels. Our data showed that BLM induced A549 cell death by a mechanism involving oxidative stress and mitochondrial dysfunction. NACA had a protective role against BLM-induced toxicity by inhibiting lipid peroxidation, scavenging ROS, and preserving intracellular GSH and ΔΨm. NACA can potentially be developed into a promising adjunctive therapeutic option for patients undergoing chemotherapy with BLM. PMID:23805793

  9. Identification and properties of pathways for K+ transport in guinea-pig and rat alveolar epithelial type II cells.

    PubMed Central

    Kemp, P J; Roberts, G C; Boyd, C A

    1994-01-01

    86Rb+ was used to study potassium uptake and efflux in type II pneumocytes freshly isolated from adult guinea-pig and rat lung. Both species exhibited a substantial ouabain-sensitive component of potassium influx. In rats, most of the ouabain-resistant influx was abolished by bumetanide and removal of extracellular chloride elicited no further effect. In contrast, only a proportion of the ouabain-insensitive uptake was inhibitable by bumetanide in guinea-pigs and this species showed an additional component of influx, which was chloride dependent and which was reduced by either the K(+)-H(+)-ATPase inhibitor, omeprazole, or by the stilbene derivative, 4,4'-diisothiocyanostilbene-2,2'-disulphonate (DIDS). The chloride-dependent component was also apparent in efflux experiments in guinea-pigs, but was absent in rats. Ouabain-insensitive ATPase activity was assayed in highly purified apical membranes from guinea-pig type II pneumocytes. This activity was inhibitable by omeprazole (apparent inhibition constant, Ki, was approximately 40 microM), was potassium dependent (apparent activation constant, Ka, was approximately 200 microM) and was doubled by the addition of nigericin. While potassium transport in rat type II cells is adequately accounted for by Na(+)-K(+)-ATPase and Na(+)-K(+)-2Cl- cotransport, our data suggest the additional presence of K(+)-Cl- cotransport and K(+)-H(+)-ATPase in guinea-pig type II pneumocytes. A model of how alveolar subphase acidification may occur is proposed. PMID:8046636

  10. Krüppel-Like Factor 5 Promotes Epithelial Proliferation and DNA Damage Repair in the Intestine of Irradiated Mice

    PubMed Central

    Li, Ming; Gu, Yuan; Ma, Yan-Chao; Shang, Zeng-Fu; Wang, Chang; Liu, Fen-Ju; Cao, Jian-Ping; Wan, Hua-Jing; Zhang, Xue-Guang

    2015-01-01

    BACKGROUND & AIMS: High doses of radiation induce severe DNA damage in intestinal epithelial cells, especially crypt cells, and cause intestinal injury, but the underlying molecular mechanisms remain unclear. Krüppel-like factor 5 (KLF5), a zinc finger-containing transcription factor, is induced by various stress stimuli and is involved in cell proliferation and survival. The role of KLF5 in radiation-induced intestinal injury was investigated here. METHODS: Wild type mice were treated with 8 or 15 Gy total body irradiation (TBI). KLF5 content and cellular localization in the small intestines of irradiated mice were detected by Western blot and immunohistochemical analysis. Mice with intestinal-specific knockdown of KLF5 (Vil-Cre; Klf5fl/+ mice) were generated and their response to radiation was compared with controls. Morphological changes were determined by hematoxylin and eosin staining. Proliferation was examined by Ki67 immunostaining. The molecular response of the small intestine after KLF5 knockdown was investigated using microarrays. RESULTS: KLF5 expression correlated with the progression of intestinal damage. Decreased levels of KLF5 in the gut were associated with increased damage to the intestinal mucosa and reduced epithelial proliferation after TBI. Our microarray data disclosed that KLF5 knockdown down-regulated genes related to DNA damage repair pathways such as nucleotide excision repair, mismatch repair, non-homologous end joining and the Fanconi anemia pathway, which may suggest a novel function of KLF5. CONCLUSIONS: Our study illustrates that KLF5 may modulate DNA repair pathways to prevent intestinal injury induced by TBI. KLF5 signaling provides a novel field for identification of potential therapeutic targets for the treatment of radiation-induced intestinal damage. PMID:26681925

  11. Hypoxia-induced Deoxycytidine Kinase Contributes to Epithelial Proliferation in Pulmonary Fibrosis

    PubMed Central

    Weng, Tingting; Poth, Jens M.; Karmouty-Quintana, Harry; Garcia-Morales, Luis J.; Melicoff, Ernestina; Luo, Fayong; Chen, Ning-yuan; Evans, Christopher M.; Bunge, Raquel R.; Bruckner, Brian A.; Loebe, Matthias; Volcik, Kelly A.; Eltzschig, Holger K.

    2014-01-01

    Rationale: Idiopathic pulmonary fibrosis (IPF) is a deadly lung disease with few therapeutic options. Apoptosis of alveolar epithelial cells, followed by abnormal tissue repair characterized by hyperplastic epithelial cell formation, is a pathogenic process that contributes to the progression of pulmonary fibrosis. However, the signaling pathways responsible for increased proliferation of epithelial cells remain poorly understood. Objectives: To investigate the role of deoxycytidine kinase (DCK), an important enzyme for the salvage of deoxynucleotides, in the progression of pulmonary fibrosis. Methods: DCK expression was examined in the lungs of patients with IPF and mice exposed to bleomycin. The regulation of DCK expression by hypoxia was studied in vitro and the importance of DCK in experimental pulmonary fibrosis was examined using a DCK inhibitor and alveolar epithelial cell-specific knockout mice. Measurements and Main Results: DCK was elevated in hyperplastic alveolar epithelial cells of patients with IPF and in mice exposed to bleomycin. Increased DCK was localized to cells associated with hypoxia, and hypoxia directly induced DCK in alveolar epithelial cells in vitro. Hypoxia-induced DCK expression was abolished by silencing hypoxia-inducible factor 1α and treatment of bleomycin-exposed mice with a DCK inhibitor attenuated pulmonary fibrosis in association with decreased epithelial cell proliferation. Furthermore, DCK expression, and proliferation of epithelial cells and pulmonary fibrosis was attenuated in mice with conditional deletion of hypoxia-inducible factor 1α in the alveolar epithelium. Conclusions: Our findings suggest that the induction of DCK after hypoxia plays a role in the progression of pulmonary fibrosis by contributing to alveolar epithelial cell proliferation. PMID:25358054

  12. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air–liquid interface

    DOE PAGESBeta

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica A.; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2013-12-02

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specificmore » fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. In conclusion, together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.« less

  13. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air–liquid interface

    SciTech Connect

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica A.; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2013-12-02

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specific fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. In conclusion, together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes

  14. Reactive oxygen species mediated DNA damage in human lung alveolar epithelial (A549) cells from exposure to non-cytotoxic MFI-type zeolite nanoparticles.

    PubMed

    Bhattacharya, Kunal; Naha, Pratap C; Naydenova, Izabela; Mintova, Svetlana; Byrne, Hugh J

    2012-12-17

    MFI-50 nanoparticles was found to accumulate over a longer period of time as compared to MFI-100 nanoparticles. The study therefore points towards the capability of the non-cytotoxic zeolite nanoparticles to induce oxidative stress resulting in short-term altered cellular metabolism up-regulation and genomic instability. Although the damage was found to be short-lived, its persistence over longer durations, or stabilization cannot be neglected. Further studies are in progress to yield a better understanding of the mechanisms for oxidative stress and resulting cascade of events leading to genetic damage in the human lung alveolar epithelial cells following exposure to zeolite nanoparticles of different sizes. PMID:23103338

  15. Regulation of pulmonary surfactant synthesis in fetal rat type II alveolar epithelial cells by microRNA-26a.

    PubMed

    Zhang, Xiao-Qun; Zhang, Pan; Yang, Yang; Qiu, Jie; Kan, Qin; Liang, Hong-Lu; Zhou, Xiao-Yu; Zhou, Xiao-Guang

    2014-09-01

    Pulmonary surfactant, a unique developmentally regulated, phospholipid-rich lipoprotein, is synthesized by the type II epithelial cells (AECII) of the pulmonary alveolus, where it is stored in organelles termed lamellar bodies. The synthesis of pulmonary surfactant is under multifactorial control and is regulated by a number of hormones and factors, including glucocorticoids, prolactin, insulin, growth factors, estrogens, androgens, thyroid hormones, and catecholamines acting through beta-adrenergic receptors, and cAMP. While there is increasing evidence that microRNAs (miRNAs) are involved in the regulation of almost every cellular and physiological process, the potential role of miRNAs in the regulation of pulmonary surfactant synthesis remains unknown. miRNA-26a (miR-26a) has been predicted to target SMAD1, one of the bone morphogenetic protein (BMP) receptor downstream signaling proteins that plays a key role in differentiation of lung epithelial cells during lung development. In this study, we explored the regulation role of miR-26a in the synthesis of pulmonary surfactant. An adenoviral miR-26a overexpression vector was constructed and introduced into primary cultured fetal AECII. GFP fluorescence was observed to determinate the transfection efficiency and miR-26a levels were measured by RT-PCR. MTT was performed to analyze AECII viability. qRT-PCR and Western blotting were used to determine the mRNA and protein level of SMAD1 and surfactant-associated proteins. The results showed that miR-26a in fetal AECII was overexpressed after the transfection, and that the overexpression of miR-26a inhibited pulmonary surfactant synthesis in AECII. There was no significant change in cell proliferation. Our results further showed that overexpression of miR-26a reduced the SMAD1 expression both in mRNA and protein level in fetal AECII. These findings indicate that miR-26a regulates surfactant synthesis in fetal AECII through SMAD1. PMID:24395810

  16. Human neutrophil elastase regulates the expression and secretion of elafin (elastase-specific inhibitor) in type II alveolar epithelial cells.

    PubMed

    Reid, P T; Marsden, M E; Cunningham, G A; Haslett, C; Sallenave, J M

    1999-08-20

    Elafin is a low molecular weight antiproteinase believed to be important in the regulation of elastase mediated tissue damage. The expression of elafin is known to be regulated by proinflammatory cytokines such as interleukin-1 beta and tumour necrosis factor but little was known regarding the effect of human neutrophil elastase (HNE). Employing a chloramphenicol acetyltransferase reporter construct of the human elafin gene, reverse transcription PCR from total cellular RNA and ELISA techniques, we have examined the effect of human neutrophil elastase on the transcription and secretion of human elafin in the pulmonary epithelial A549 cell line. Stimulation with HNE at concentrations of 10(-10) and 10(-11) M resulted in a significant upregulation of elafin promoter activity. Similarly, transcription of the endogenous human elafin gene was upregulated with HNE concentrations ranging from 10(-10) to 10(-12) M. In addition, we demonstrate that stimulation with HNE at concentrations ranging from 10(-9) and 10(-12) M resulted in a significant reduction in the secreted elafin protein as measured in the cell supernatant. These results provide further evidence for a role of elafin in the regulation of HNE driven proteolysis of the extracellular matrix. PMID:10486558

  17. Bone Marrow Cells Expressing Clara Cell Secretory Protein Increase Epithelial Repair After Ablation of Pulmonary Clara Cells

    PubMed Central

    Bustos, Martha L; Mura, Marco; Marcus, Paula; Hwang, David; Ludkovski, Olga; Wong, Amy P; Waddell, Thomas K

    2013-01-01

    We have previously reported a subpopulation of bone marrow cells (BMC) that express Clara cell secretory protein (CCSP), generally felt to be specific to lung Clara cells. Ablation of lung Clara cells has been reported using a transgenic mouse that expresses thymidine kinase under control of the CCSP promoter. Treatment with ganciclovir results in permanent elimination of CCSP+ cells, failure of airway regeneration, and death. To determine if transtracheal delivery of wild-type bone marrow CCSP+ cells is beneficial after ablation of lung CCSP+ cells, transgenic mice were treated with ganciclovir followed by transtracheal administration of CCSP+ or CCSP− BMC. Compared with mice administered CCSP− cells, mice treated with CCSP+ cells had more donor cells lining the airway epithelium, where they expressed epithelial markers including CCSP. Although donor CCSP+ cells did not substantially repopulate the airway, their administration resulted in increased host ciliated cells, better preservation of airway epithelium, reduction of inflammatory cells, and an increase in animal survival time. Administration of CCSP+ BMC is beneficial after permanent ablation of lung Clara cells by increasing bronchial epithelial repair. Therefore, CCSP+ BMC could be important for treatment of lung diseases where airways re-epithelialization is compromised. PMID:23609017

  18. 7,12-dimethylbenz(a)anthracene-induced DNA binding and repair synthesis in susceptible and nonsusceptible mammary epithelial cells in culture. [Rats

    SciTech Connect

    Tay, L.K.; Russo, J.

    1981-07-01

    The effect of age and parity on the binding of 7,12-dimethylbenz(a)anthracene (DMBA) to DNA and the repair of DMBA-damaged DNA have been demonstrated in logarithmic phase and confluent mammary epithelial cell cultures from young virgin (YV), old virgin (OV), and parous (P) noninbred and inbred Sprague-Dawley rats. Excision repair was determined by measuring, in the presence of hydroxyurea and 5-bromodeoxyuridine, tritiated thymidine incorporation into DNA during the repair process. These results suggest that age and parity not only lower the binding of DMBA to mammary epithelial cell DNA but also increase the efficiency of DNA repair processes, which may explain the lower susceptibility of OV and P rats to DMBA-induced mammary carcinogenesis.

  19. A Novel Approach for Ovine Primary Alveolar Epithelial Type II Cell Isolation and Culture from Fresh and Cryopreserved Tissue Obtained from Premature and Juvenile Animals

    PubMed Central

    Marcinkiewicz, Mariola M.; Baker, Sandy T.; Wu, Jichuan; Hubert, Terrence L.; Wolfson, Marla R.

    2016-01-01

    The in vivo ovine model provides a clinically relevant platform to study cardiopulmonary mechanisms and treatments of disease; however, a robust ovine primary alveolar epithelial type II (ATII) cell culture model is lacking. The objective of this study was to develop and optimize ovine lung tissue cryopreservation and primary ATII cell culture methodologies for the purposes of dissecting mechanisms at the cellular level to elucidate responses observed in vivo. To address this, we established in vitro submerged and air-liquid interface cultures of primary ovine ATII cells isolated from fresh or cryopreserved lung tissues obtained from mechanically ventilated sheep (128 days gestation—6 months of age). Presence, abundance, and mRNA expression of surfactant proteins was assessed by immunocytochemistry, Western Blot, and quantitative PCR respectively on the day of isolation, and throughout the 7 day cell culture study period. All biomarkers were significantly greater from cells isolated from fresh than cryopreserved tissue, and those cultured in air-liquid interface as compared to submerged culture conditions at all time points. Surfactant protein expression remained in the air-liquid interface culture system while that of cells cultured in the submerged system dissipated over time. Despite differences in biomarker magnitude between cells isolated from fresh and cryopreserved tissue, cells isolated from cryopreserved tissue remained metabolically active and demonstrated a similar response as cells from fresh tissue through 72 hr period of hyperoxia. These data demonstrate a cell culture methodology using fresh or cryopreserved tissue to support study of ovine primary ATII cell function and responses, to support expanded use of biobanked tissues, and to further understanding of mechanisms that contribute to in vivo function of the lung. PMID:26999050

  20. Oxidative stress, apoptosis, and cell cycle arrest are induced in primary fetal alveolar type II epithelial cells exposed to fine particulate matter from cooking oil fumes.

    PubMed

    Liu, Ying; Chen, Yan-Yan; Cao, Ji-Yu; Tao, Fang-Biao; Zhu, Xiao-Xia; Yao, Ci-Jiang; Chen, Dao-Jun; Che, Zhen; Zhao, Qi-Hong; Wen, Long-Ping

    2015-07-01

    Epidemiological studies demonstrate a linkage between morbidity and mortality and particulate matter (PM), particularly fine particulate matter (PM2.5) that can readily penetrate into the lungs and are therefore more likely to increase the incidence of respiratory and cardiovascular diseases. The present study investigated the compositions of cooking oil fume (COF)-derived PM2.5, which is the major source of indoor pollution in China. Furthermore, oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest induced by COF-derived PM2.5 in primary fetal alveolar type II epithelial cells (AEC II cells) were also detected. N-acetyl-L-cysteine (NAC), a radical scavenger, was used to identify the role of oxidative stress in the abovementioned processes. Our results suggested that compositions of COF-derived PM2.5 are obviously different to PM2.5 derived from other sources, and COF-derived PM2.5 led to cell death, oxidative stress, apoptosis, and G0/G1 cell arrest in primary fetal AEC II cells. Furthermore, the results also showed that COF-derived PM2.5 induced apoptosis through the endoplasmic reticulum (ER) stress pathway, which is indicated by the increased expression of ER stress-related apoptotic markers, namely GRP78 and caspase-12. Besides, the induction of oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest was reversed by pretreatment with NAC. These findings strongly suggested that COF-derived PM2.5-induced toxicity in primary fetal AEC II cells is mediated by increased oxidative stress, accompanied by ER stress which results in apoptosis. PMID:25634364

  1. D1398G Variant of MET Is Associated with Impaired Signaling of Hepatocyte Growth Factor in Alveolar Epithelial Cells and Lung Fibroblasts.

    PubMed

    Atanelishvili, Ilia; Shirai, Yuichiro; Akter, Tanjina; Noguchi, Atsushi; Ash, Kurt T; Misra, Suniti; Ghatak, Sibnath; Silver, Richard M; Bogatkevich, Galina S

    2016-01-01

    Pulmonary fibrosis represents the terminal stage of a diverse group of lung diseases including scleroderma associated interstitial lung disease. The molecular mechanisms underlying the pathogenesis of lung fibrosis are not well understood and there is a great need for more effective treatment for this lethal disease. We recently discovered a small fragment of hepatocyte growth factor (HGF) receptor MET as a peptide designated "M10," with strong antifibrotic properties. Furthermore, we showed that aspartic acid at position 1398 of MET is essential for M10 generation. The current study was undertaken to investigate the D1398G variant of MET in which aspartic acid at position 1398 was mutated to glycine resulting in loss of M10. We demonstrate that lung fibroblasts, A549, and primary alveolar epithelial cells (AEC) expressing D1398G MET exhibit reduced auto-phosphorylation on tyrosine residues and reduced activation of Ras and MAPK. HGF treatment of scleroderma lung fibroblasts as well as HGF treatment of TGFβ-treated normal lung fibroblasts transfected with wild type MET is associated with decreased collagen, connective tissue growth factor (CTGF, CCN2) and smooth muscle α-actin (SMA). However, HGF has no such effects in cells transfected with MET D1398G. Cisplatin- and FasL-induced apoptosis is significantly reduced in AEC transfected with MET wild type, but not in AEC transfected with MET D1398G. We conclude that the D1398G variant of MET is associated with compromised phosphorylation and impaired HGF signaling in lung fibroblasts and AEC, two cell types implicated in the pathogenesis of pulmonary fibrosis associated with scleroderma. Ongoing studies will explore the frequency of this variant and its relationship to pulmonary outcomes in scleroderma patients. PMID:27584154

  2. Carbocisteine attenuates TNF-α-induced inflammation in human alveolar epithelial cells in vitro through suppressing NF-κB and ERK1/2 MAPK signaling pathways

    PubMed Central

    Wang, Wei; Guan, Wei-jie; Huang, Rong-quan; Xie, Yan-qing; Zheng, Jin-ping; Zhu, Shao-xuan; Chen, Mao; Zhong, Nan-shan

    2016-01-01

    Aim: We previously proven that carbocisteine, a conventional mucolytic drug, remarkably reduced the rate of acute exacerbations and improved the quality of life in the patients with chronic obstructive pulmonary disease. In this study we investigated the mechanisms underlying the anti-inflammatory effects of carbocisteine in human alveolar epithelial cells in vitro. Methods: Human lung adenocarcinoma cell line A549 was treated with TNF-α (10 ng/mL). Carbocisteine was administered either 24 h prior to or after TNF-α exposure. The cytokine release and expression were measured using ELISA and qRT-PCR. Activation of NF-κB was analyzed with Western blotting, immunofluorescence assay and luciferase reporter gene assay. The expression of ERK1/2 MAPK signaling proteins was assessed with Western blotting. Results: Carbocisteine (10, 100, 1000 μmol/L), administered either before or after TNF-α exposure, dose-dependently suppressed TNF-α-induced inflammation in A549 cells, as evidenced by diminished release of IL-6 and IL-8, and diminished mRNA expression of IL-6, IL-8, TNF-α, MCP-1 and MIP-1β. Furthermore, pretreatment with carbocisteine significantly decreased TNF-α-induced phosphorylation of NF-κB p65 and ERK1/2 MAPK, and inhibited the nuclear translocation of p65 subunit in A549 cells. In an NF-κB luciferase reporter system, pretreatment with carbocisteine dose-dependently inhibited TNF-α-induced transcriptional activity of NF-κB. Conclusion: Carbocisteine effectively suppresses TNF-α-induced inflammation in A549 cells via suppressing NF-κB and ERK1/2 MAPK signaling pathways. PMID:26997568

  3. Benzo[a]pyrene and tumor necrosis factor-α coordinately increase genotoxic damage and the production of proinflammatory mediators in alveolar epithelial type II cells.

    PubMed

    Umannová, Lenka; Machala, Miroslav; Topinka, Jan; Schmuczerová, Jana; Krčmář, Pavel; Neča, Jiří; Šujanová, Klára; Kozubík, Alois; Vondráček, Jan

    2011-10-10

    Alveolar type II epithelial (AEII) cells regulate lung inflammatory response and, simultaneously, they are a target of environmental carcinogenic factors. We employed an in vitro model of rat AEII cells, the RLE-6TN cell line, in order to analyze the interactive effects of tumor necrosis factor-α (TNF-α), a cytokine which plays a key role in the initiation of inflammatory responses in the lung, and benzo[a]pyrene (BaP), a highly carcinogenic polycyclic aromatic hydrocarbon. TNF-α strongly augmented the formation of stable BaP diol epoxide-DNA adducts in AEII cells, which was associated with enhanced p53-Ser15 phosphorylation and decreased cell survival. The increased genotoxicity of BaP was associated with altered expression of cytochrome P450 (CYP) enzymes involved in its bioactivation, a simultaneous suppression of CYP1A1 and enhancement of CYP1B1 expression. Importantly, BaP and TNF-α acted synergistically to upregulate key inflammatory regulators in AEII cells, including the expression of inducible NO synthase and cyclooxygenase-2 (COX-2), and enhanced prostaglandin E2 production and expression of proinflammatory cytokines, such as TNF-α, interleukin-1β and interleukin-6. We observed that BaP and TNF-α together strongly activated p38 kinase, a principal regulator of inflammatory response. SB202190, a specific p38 inhibitor, prevented induction of both COX-2 and proinflammatory cytokines, thus confirming that p38 activity was crucial for the observed inflammatory reaction. Taken together, our data demonstrated, for the first time, that a proinflammatory cytokine and an environmental PAH may interact to potentiate both DNA damage and the inflammatory response in AEII cells, which may occur through coordinated upregulation of p38 activity. PMID:21745554

  4. A Novel Approach for Ovine Primary Alveolar Epithelial Type II Cell Isolation and Culture from Fresh and Cryopreserved Tissue Obtained from Premature and Juvenile Animals.

    PubMed

    Marcinkiewicz, Mariola M; Baker, Sandy T; Wu, Jichuan; Hubert, Terrence L; Wolfson, Marla R

    2016-01-01

    The in vivo ovine model provides a clinically relevant platform to study cardiopulmonary mechanisms and treatments of disease; however, a robust ovine primary alveolar epithelial type II (ATII) cell culture model is lacking. The objective of this study was to develop and optimize ovine lung tissue cryopreservation and primary ATII cell culture methodologies for the purposes of dissecting mechanisms at the cellular level to elucidate responses observed in vivo. To address this, we established in vitro submerged and air-liquid interface cultures of primary ovine ATII cells isolated from fresh or cryopreserved lung tissues obtained from mechanically ventilated sheep (128 days gestation-6 months of age). Presence, abundance, and mRNA expression of surfactant proteins was assessed by immunocytochemistry, Western Blot, and quantitative PCR respectively on the day of isolation, and throughout the 7 day cell culture study period. All biomarkers were significantly greater from cells isolated from fresh than cryopreserved tissue, and those cultured in air-liquid interface as compared to submerged culture conditions at all time points. Surfactant protein expression remained in the air-liquid interface culture system while that of cells cultured in the submerged system dissipated over time. Despite differences in biomarker magnitude between cells isolated from fresh and cryopreserved tissue, cells isolated from cryopreserved tissue remained metabolically active and demonstrated a similar response as cells from fresh tissue through 72 hr period of hyperoxia. These data demonstrate a cell culture methodology using fresh or cryopreserved tissue to support study of ovine primary ATII cell function and responses, to support expanded use of biobanked tissues, and to further understanding of mechanisms that contribute to in vivo function of the lung. PMID:26999050

  5. The Role of Alveolar Epithelial Type II-Like Cells in Uptake of Structurally Different Antigens and in Polarisation of Local Immune Responses

    PubMed Central

    Akgün, Johnnie; Schabussova, Irma; Schwarzer, Martin; Kozakova, Hana; Kundi, Michael; Wiedermann, Ursula

    2015-01-01

    Background Our previous studies on intranasal tolerance induction demonstrated reduction of allergic responses with different allergen constructs. The underlying mechanisms varied depending on their conformation or size. Objective The aim of the present study was to compare the uptake of two structurally different allergen molecules within the respiratory tract following intranasal application. Methods The three-dimensional Bet v 1 (Bv1-Protein) and the T cell epitope peptide of Bet v 1 (Bv1-Peptide) were labelled with 5,6-Carboxyfluorescein (FAM) and their uptake was investigated in lung cells and cells of the nasal associated lymphoid tissue from naive and sensitised BALB/c mice. Phenotypic characterisation of FAM+ lung cells after antigen incubation in vitro and after intranasal application was performed by flow cytometry. Impact of Bv1-Protein and Bv1-Peptide on cytokine profiles and gene expression in vivo or in an alveolar epithelial type II (ATII) cell line were assessed in mono- and co-cultures with monocytes using ELISA and quantitative real-time PCR. Results Both antigens were taken up preferably by ATII-like cells (ATII-LCs) in naive mice, and by macrophages in sensitised mice. After intranasal application, Bv1-Peptide was taken up faster and more efficiently than Bv1-Protein. In vivo and in vitro experiments revealed that Bv1-Protein induced the transcription of thymic stromal lymphopoietin mRNA while Bv1-Peptide induced the transcription of IL-10 and MCP1 mRNA in ATII-LCs. Conclusion and Clinical Relevance Both tested antigens were taken up by ATII-LCs under steady state conditions and induced different polarisation of the immune responses. These data may have an important impact for the generation of novel and more effective prophylactic or therapeutic tools targeting the respiratory mucosa. PMID:25894334

  6. Application of linear integration in the morphometric study of mild and severe pulmonary alveolar injury.

    PubMed

    Coulombe, P A; Côté, M G

    1988-02-01

    In this study we applied linear integration morphometry to characterize the pulmonary alveolar reaction to toxic injury and to study possible relationships between the major tissue and cell compartments of alveolar tissue, normal and injured. Acute alveolar injury of mild and severe intensity was induced in Swiss-Webster mice by the ip administration of the chemicals diquat (4 mg/kg) and butylated hydroxytoluene (BHT; 400 mg/kg). Animals were sacrificed at Days 1 and 2 after diquat treatment and at Days 1, 3, and 5 after BHT treatment. Sampling and analysis of alveolar tissue were conducted at both levels of light and electron microscopy. Thickness distributions of arithmetic and reciprocal intercepts, as well as the arithmetic (tau) and harmonic (tau h) mean thicknesses, were established for the following alveolar compartments: septum, alveolo-capillary barrier (ACB), type I and total epithelia, capillary endothelium, and interstitium. A relative measure of the pulmonary diffusion capacity and the capillary load of alveolar septa were also determined. The parameters calculated from these thickness distributions, such as their slopes, percentages of thin intercepts, and tau/tau h ratios, proved very sensitive and useful in the detection and characterization of morphological alterations in the type I epithelial and capillary endothelial cells following either mild or severe alveolar injury. The epithelial, endothelial, and interstitial layers of pulmonary septa were all characterized by their own pattern of structural changes, so that it proved impossible to relate them in a simple way to the tissue reaction, which can be easily studied at the light microscopic level. Linear integration morphometry thus proved very useful as a morphometric approach to the study of pulmonary alveolar injury and repair. PMID:3335253

  7. Alveolar wall relations.

    PubMed

    Gil, J

    1982-01-01

    We have presented a highly dynamic view of the alveolar septum and its main enclosed structure, the dense capillary network. The septal or perimicrovascular interstitium is the space between alveolar epithelial sheets after exclusion of the capillary network. It contains cells, fibers, and a viscous matrix. Capillaries form a very complex network, which closely follows the geometry of the terminal airways and participates in functional adaptations of the wall, particularly septal pleating. The level of filling and configuration of different capillaries ranging from collapse to full distension are variable, depending on factors such as transmural balance of forces but also on tissular configuration. Alveolar flooding of any cause will produce an immediate change of capillary configuration and volume. PMID:6953828

  8. Galectin-7 modulates the length of the primary cilia and wound repair in polarized kidney epithelial cells.

    PubMed

    Rondanino, Christine; Poland, Paul A; Kinlough, Carol L; Li, Hui; Rbaibi, Youssef; Myerburg, Michael M; Al-bataineh, Mohammad M; Kashlan, Ossama B; Pastor-Soler, Nuria M; Hallows, Kenneth R; Weisz, Ora A; Apodaca, Gerard; Hughey, Rebecca P

    2011-09-01

    Galectins (Gal) are β-galactoside-binding proteins that function in epithelial development and homeostasis. An overlapping role for Gal-3 and Gal-7 in wound repair was reported in stratified epithelia. Although Gal-7 was thought absent in simple epithelia, it was reported in a proteomic analysis of cilia isolated from cultured human airway, and we recently identified Gal-7 transcripts in Madin-Darby canine kidney (MDCK) cells (Poland PA, Rondanino C, Kinlough CL, Heimburg-Molinaro J, Arthur CM, Stowell SR, Smith DF, Hughey RP. J Biol Chem 286: 6780-6790, 2011). We now report that Gal-7 is localized exclusively on the primary cilium of MDCK, LLC-PK(1) (pig kidney), and mpkCCD(c14) (mouse kidney) cells as well as on cilia in the rat renal proximal tubule. Gal-7 is also present on most cilia of multiciliated cells in human airway epithelia primary cultures. Interestingly, exogenous glutathione S-transferase (GST)-Gal-7 bound the MDCK apical plasma membrane as well as the cilium, while the lectin Ulex europeaus agglutinin, with glycan preferences similar to Gal-7, bound the basolateral plasma membrane as well as the cilium. In pull-down assays, β1-integrin isolated from either the basolateral or apical/cilia membranes of MDCK cells was similarly bound by GST-Gal-7. Selective localization of Gal-7 to cilia despite the presence of binding sites on all cell surfaces suggests that intracellular Gal-7 is specifically delivered to cilia rather than simply binding to surface glycoconjugates after generalized secretion. Moreover, depletion of Gal-7 using tetracycline-induced short-hairpin RNA in mpkCCD(c14) cells significantly reduced cilia length and slowed wound healing in a scratch assay. We conclude that Gal-7 is selectively targeted to cilia and plays a key role in surface stabilization of glycoconjugates responsible for integrating cilia function with epithelial repair. PMID:21677144

  9. Defective DNA single-strand break repair is responsible for senescence and neoplastic escape of epithelial cells.

    PubMed

    Nassour, Joe; Martien, Sébastien; Martin, Nathalie; Deruy, Emeric; Tomellini, Elisa; Malaquin, Nicolas; Bouali, Fatima; Sabatier, Laure; Wernert, Nicolas; Pinte, Sébastien; Gilson, Eric; Pourtier, Albin; Pluquet, Olivier; Abbadie, Corinne

    2016-01-01

    The main characteristic of senescence is its stability which relies on the persistence of DNA damage. We show that unlike fibroblasts, senescent epithelial cells do not activate an ATM-or ATR-dependent DNA damage response (DDR), but accumulate oxidative-stress-induced DNA single-strand breaks (SSBs). These breaks remain unrepaired because of a decrease in PARP1 expression and activity. This leads to the formation of abnormally large and persistent XRCC1 foci that engage a signalling cascade involving the p38MAPK and leading to p16 upregulation and cell cycle arrest. Importantly, the default in SSB repair also leads to the emergence of post-senescent transformed and mutated precancerous cells. In human-aged skin, XRCC1 foci accumulate in the epidermal cells in correlation with a decline of PARP1, whereas DDR foci accumulate mainly in dermal fibroblasts. These findings point SSBs as a DNA damage encountered by epithelial cells with aging which could fuel the very first steps of carcinogenesis. PMID:26822533

  10. Defective DNA single-strand break repair is responsible for senescence and neoplastic escape of epithelial cells

    PubMed Central

    Nassour, Joe; Martien, Sébastien; Martin, Nathalie; Deruy, Emeric; Tomellini, Elisa; Malaquin, Nicolas; Bouali, Fatima; Sabatier, Laure; Wernert, Nicolas; Pinte, Sébastien; Gilson, Eric; Pourtier, Albin; Pluquet, Olivier; Abbadie, Corinne

    2016-01-01

    The main characteristic of senescence is its stability which relies on the persistence of DNA damage. We show that unlike fibroblasts, senescent epithelial cells do not activate an ATM-or ATR-dependent DNA damage response (DDR), but accumulate oxidative-stress-induced DNA single-strand breaks (SSBs). These breaks remain unrepaired because of a decrease in PARP1 expression and activity. This leads to the formation of abnormally large and persistent XRCC1 foci that engage a signalling cascade involving the p38MAPK and leading to p16 upregulation and cell cycle arrest. Importantly, the default in SSB repair also leads to the emergence of post-senescent transformed and mutated precancerous cells. In human-aged skin, XRCC1 foci accumulate in the epidermal cells in correlation with a decline of PARP1, whereas DDR foci accumulate mainly in dermal fibroblasts. These findings point SSBs as a DNA damage encountered by epithelial cells with aging which could fuel the very first steps of carcinogenesis. PMID:26822533

  11. Plasticity of Hopx+ Type I alveolar cells to regenerate Type II cells in the lung

    PubMed Central

    Jain, Rajan; Barkauskas, Christina E.; Takeda, Norifumi; Bowie, Emily J.; Aghajanian, Haig; Wang, Qiaohong; Padmanabhan, Arun; Manderfield, Lauren J.; Gupta, Mudit; Li, Deqiang; Li, Li; Trivedi, Chinmay M.; Hogan, Brigid L. M.; Epstein, Jonathan A.

    2015-01-01

    The plasticity of differentiated cells in adult tissues undergoing repair is an area of intense research. Pulmonary alveolar Type II cells produce surfactant and function as progenitors in the adult, demonstrating both self-renewal and differentiation into gas exchanging Type I cells. In vivo, Type I cells are thought to be terminally differentiated and their ability to give rise to alternate lineages has not been reported. Here, we show that Hopx becomes restricted to Type I cells during development. However, unexpectedly, lineage-labeled Hopx+ cells both proliferate and generate Type II cells during adult alveolar regrowth following partial pneumonectomy. In clonal 3D culture, single Hopx+ Type I cells generate organoids composed of Type I and Type II cells, a process modulated by TGFβ signaling. These findings demonstrate unanticipated plasticity of Type I cells and a bi-directional lineage relationship between distinct differentiated alveolar epithelial cell types in vivo and in single cell culture. PMID:25865356

  12. Denervation resulting in dento-alveolar ankylosis associated with decreased Malassez epithelium.

    PubMed

    Fujiyama, K; Yamashiro, T; Fukunaga, T; Balam, T A; Zheng, L; Takano-Yamamoto, T

    2004-08-01

    Inferior alveolar nerve denervation causes appreciable decreases in the distribution of epithelial rests of Malassez. To explore roles of the Malassez epithelium, we attempted to evaluate possible changes in dento-alveolar tissues surrounding this epithelium by experimental denervation. We found that denervation led to dento-alveolar ankylosis with a decrease in the width of the periodontal spaces. Interestingly, with regeneration of the Malassez epithelium 10 weeks after the denervation, the periodontal space width showed a correspondingly significant increase. These findings suggest that the Malassez epithelium may be involved in the maintenance of periodontal space and that sensory innervation might be indirectly associated with it. In addition, it is of interest that denervation activated root resorption of the coronal root surface and that the consequently resorbed lacunae were repaired by cellular cementum. It is suggested that Malassez epithelium may negatively regulate root resorption and induce acellular cementum formation. PMID:15271971

  13. Plasticity of Hopx(+) type I alveolar cells to regenerate type II cells in the lung.

    PubMed

    Jain, Rajan; Barkauskas, Christina E; Takeda, Norifumi; Bowie, Emily J; Aghajanian, Haig; Wang, Qiaohong; Padmanabhan, Arun; Manderfield, Lauren J; Gupta, Mudit; Li, Deqiang; Li, Li; Trivedi, Chinmay M; Hogan, Brigid L M; Epstein, Jonathan A

    2015-01-01

    The plasticity of differentiated cells in adult tissues undergoing repair is an area of intense research. Pulmonary alveolar type II cells produce surfactant and function as progenitors in the adult, demonstrating both self-renewal and differentiation into gas exchanging type I cells. In vivo, type I cells are thought to be terminally differentiated and their ability to give rise to alternate lineages has not been reported. Here we show that Hopx becomes restricted to type I cells during development. However, unexpectedly, lineage-labelled Hopx(+) cells both proliferate and generate type II cells during adult alveolar regrowth following partial pneumonectomy. In clonal 3D culture, single Hopx(+) type I cells generate organoids composed of type I and type II cells, a process modulated by TGFβ signalling. These findings demonstrate unanticipated plasticity of type I cells and a bidirectional lineage relationship between distinct differentiated alveolar epithelial cell types in vivo and in single-cell culture. PMID:25865356

  14. Faster DNA Repair of Ultraviolet-Induced Cyclobutane Pyrimidine Dimers and Lower Sensitivity to Apoptosis in Human Corneal Epithelial Cells than in Epidermal Keratinocytes.

    PubMed

    Mallet, Justin D; Dorr, Marie M; Drigeard Desgarnier, Marie-Catherine; Bastien, Nathalie; Gendron, Sébastien P; Rochette, Patrick J

    2016-01-01

    Absorption of UV rays by DNA generates the formation of mutagenic cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4PP). These damages are the major cause of skin cancer because in turn, they can lead to signature UV mutations. The eye is exposed to UV light, but the cornea is orders of magnitude less prone to UV-induced cancer. In an attempt to shed light on this paradox, we compared cells of the corneal epithelium and the epidermis for UVB-induced DNA damage frequency, repair and cell death sensitivity. We found similar CPD levels but a 4-time faster UVB-induced CPD, but not 6-4PP, repair and lower UV-induced apoptosis sensitivity in corneal epithelial cells than epidermal. We then investigated levels of DDB2, a UV-induced DNA damage recognition protein mostly impacting CPD repair, XPC, essential for the repair of both CPD and 6-4PP and p53 a protein upstream of the genotoxic stress response. We found more DDB2, XPC and p53 in corneal epithelial cells than in epidermal cells. According to our results analyzing the protein stability of DDB2 and XPC, the higher level of DDB2 and XPC in corneal epithelial cells is most likely due to an increased stability of the protein. Taken together, our results show that corneal epithelial cells have a better efficiency to repair UV-induced mutagenic CPD. On the other hand, they are less prone to UV-induced apoptosis, which could be related to the fact that since the repair is more efficient in the HCEC, the need to eliminate highly damaged cells by apoptosis is reduced. PMID:27611318

  15. Drosophila Imaginal Discs as a Model of Epithelial Wound Repair and Regeneration

    PubMed Central

    Smith-Bolton, Rachel

    2016-01-01

    Significance: The Drosophila larval imaginal discs, which form the adult fly during metamorphosis, are an established model system for the study of epithelial tissue damage. The disc proper is a simple columnar epithelium, but it contains complex patterning and cell-fate specification, and is genetically tractable. These features enable unbiased genetic screens to identify genes involved in all aspects of the wound response, from sensing damage to wound closure, initiation of regeneration, and re-establishment of proper cell fates. Identification of the genes that facilitate epithelial wound closure and regeneration will enable development of more sophisticated wound treatments for clinical use. Recent Advances: Imaginal disc epithelia can be damaged in many different ways, including fragmentation, induction of cell death, and irradiation. Recent work has demonstrated that the tissue's response to damage varies depending on how the wound was induced. Here, we summarize the different responses activated in these epithelial tissues after the different types of damage. Critical Issues: These studies highlight that not all wounds elicit the same response from the surrounding tissue. A complete understanding of the various wound-healing mechanisms in Drosophila will be a first step in understanding how to manage damaged human tissues and optimize healing in different clinical contexts. Future Directions: Further work is necessary to understand the similarities and differences among an epithelial tissue's responses to different insults. Ongoing studies will identify the genes and pathways employed by injured imaginal discs. Thus, work in this genetically tractable system complements work in more conventional wound-healing models. PMID:27274435

  16. Sphingosine 1-Phosphate-Induced ICAM-1 Expression via NADPH Oxidase/ROS-Dependent NF-κB Cascade on Human Pulmonary Alveolar Epithelial Cells

    PubMed Central

    Lin, Chih-Chung; Yang, Chien-Chung; Cho, Rou-Ling; Wang, Chen-Yu; Hsiao, Li-Der; Yang, Chuen-Mao

    2016-01-01

    The intercellular adhesion molecule-1 (ICAM-1) expression is frequently correlated with the lung inflammation. In lung injury, sphingosine-1-phosphate (S1P, bioactive sphingolipid metabolite), participate gene regulation of adhesion molecule in inflammation progression and aggravate tissue damage. To investigate the transduction mechanisms of the S1P in pulmonary epithelium, we demonstrated that exposure of HPAEpiCs (human pulmonary alveolar epithelial cells) to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCδ), PF431396 (PYK2), diphenyleneiodonium chloride (DPI), apocynin (NADPH oxidase), Edaravone (ROS), and Bay11-7082 (NF-κB). Consistently, knockdown with siRNA transfection of PKCδ, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A) and Gi/o-coupled receptor antagonist (GPA2) also blocked the upregulation of ICAM-1 protein and mRNA induced by S1P. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCδ-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-κB p65 phosphorylation and nuclear translocation in HPAEpiCs. Activated NF-κB was blocked by Rottlerin, PF431396, APO, DPI, or Edaravone. Besides, the results of monocyte adhesion assay indicated that S1P-induced ICAM-1 expression on HPAEpiCs can enhance the monocyte attachments. In the S1P-treated mice, we found that the levels of ICAM-1 protein and mRNA in the lung fractions, the pulmonary hematoma and leukocyte count in bronchoalveolar lavage fluid were enhanced through a PKCδ/PYK2/NADPH oxidase/ROS/NF-κB signaling pathway. We concluded that S1P-accelerated lung damage is due to the ICAM-1 induction associated with

  17. Lipopolysaccharide induces ICAM-1 expression via a c-Src/NADPH oxidase/ROS-dependent NF-κB pathway in human pulmonary alveolar epithelial cells.

    PubMed

    Cho, Rou-Ling; Yang, Chien-Chung; Lee, I-Ta; Lin, Chih-Chung; Chi, Pei-Ling; Hsiao, Li-Der; Yang, Chuen-Mao

    2016-04-01

    Upregulation of intercellular adhesion molecule-1 (ICAM-1) is frequently implicated in lung inflammation. Lipopolysaccharide (LPS) has been shown to play a key role in inflammation via adhesion molecule induction and then causes lung injury. However, the mechanisms underlying LPS-induced ICAM-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain unclear. We showed that LPS induced ICAM-1 expression in HPAEpiCs, revealed by Western blotting, RT-PCR, real-time PCR, and promoter assay. Pretreatment with the inhibitor of c-Src (protein phosphatase-1, PP1), reactive oxygen species (ROS) (Edaravone), NADPH oxidase (apocynin and diphenyleneiodonium chloride), EGFR (AG1478), PDGFR (AG1296), phosphatidylinositol-3-kinase (PI3K) (LY294002), MEK1/2 (U0126), or NF-κB (Bay11-7082) and transfection with siRNAs of c-Src, EGFR, PDGFR, Akt, p47(phox), Nox2, Nox4, p42, and p65 markedly reduced LPS-induced ICAM-1 expression and monocyte adherence to HPAEpiCs challenged with LPS. In addition, we established that LPS stimulated phosphorylation of c-Src, EGFR, PDGFR, Akt, or p65, which was inhibited by pretreatment with their respective inhibitors. LPS induced Toll-like receptor 4 (TLR4), MyD88, TNF receptor-associated factor 6 (TRAF6), c-Src, p47(phox), and Rac1 complex formation 2, which was attenuated by transfection with c-Src or TRAF6 siRNA. Furthermore, LPS markedly enhanced NADPH oxidase activation and intracellular ROS generation, which were inhibited by PP1. We established that LPS induced p42/p44 MAPK activation via a c-Src/NADPH oxidase/ROS/EGFR, PDGFR/PI3K/Akt-dependent pathway in these cells. Finally, we observed that LPS significantly enhanced NF-κB and IκBα phosphorylation, NF-κB translocation, and NF-κB promoter activity, which were inhibited by PP1, Edaravone, apocynin, diphenyleneiodonium chloride, AG1478, AG1296, LY294002, or U0126. These results demonstrated that LPS induces p42/p44 MAPK activation mediated through the TLR4/MyD88/TRAF6/c

  18. An uptake of cationized ferritin by alveolar type I cells in airway-instilled goat lung: distribution of anionic sites on the epithelial surface.

    PubMed

    Atwal, O S; Viel, L; Minhas, K J

    1990-07-01

    The present study has investigated ultrastructural localization of anionic sites on the luminal surface of the alveolar epithelium of goat lung by direct airway instillation of cationized ferritin (CF) in the cranial lobe of the right lung through a bronchoscope. The cationic probe decorated preferentially the luminal plasmalemmal vesicles and plasmalemma proper of alveolar type I cell. This indicated the presence of highly charged anionic microdomains at these binding sites. The ligand was internalized in the free plasmalemmal vesicles of alveolar type I cell within 2 min. Heavy decoration of vesicles at 5 min of perfusion indicated that the amount of CF internalization increased with its concentration in the alveoli. It is suggested that exposure of alveolar surface to several gases of ruminal-origin induces changes in the surface charge of luminal plasmalemma of alveolar type I cells. The significance of these anionic plasmalemmal sites is discussed in relation to the adjustment of osmotic pressure gradient across the alveolar-capillary membrane of the ruminant lung. PMID:2390765

  19. Function and repair of dental enamel - Potential role of epithelial transport processes of ameloblasts.

    PubMed

    Varga, Gábor; Kerémi, Beáta; Bori, Erzsébet; Földes, Anna

    2015-07-01

    The hardest mammalian tissue, dental enamel is produced by ameloblasts, which are electrolyte-transporting epithelial cells. Although the end product is very different, they show many similarities to transporting epithelia of the pancreas, salivary glands and kidney. Enamel is produced in a multi-step epithelial secretory process that features biomineralization which is an interplay of secreted ameloblast specific proteins and the time-specific transport of minerals, protons and bicarbonate. First, "secretory" ameloblasts form the entire thickness of the enamel layer, but with low mineral content. Then they differentiate into "maturation" ameloblasts, which remove organic matrix from the enamel and in turn further build up hydroxyapatite crystals. The protons generated by hydroxyapatite formation need to be buffered, otherwise enamel will not attain full mineralization. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. The whole process has been the focus of many immunohistochemical and gene knock-out studies, but, perhaps surprisingly, no functional data existed for mineral ion transport by ameloblasts. However, recent studies including ours provided a better insight for molecular mechanism of mineral formation. The secretory regulation is not completely known as yet, but its significance is crucial. Impairing regulation retards or prevents completion of enamel mineralization and results in the development of hypomineralized enamel that easily erodes after dental eruption. Factors that impair this function are fluoride and disruption of pH regulators. Revealing these factors may eventually lead to the treatment of enamel hypomineralization related to genetic or environmentally induced malformation. PMID:25747281

  20. Bax-induced apoptosis shortens the life span of DNA repair defect Ku70-knockout mice by inducing emphysema.

    PubMed

    Matsuyama, Shigemi; Palmer, James; Bates, Adam; Poventud-Fuentes, Izmarie; Wong, Kelvin; Ngo, Justine; Matsuyama, Mieko

    2016-06-01

    Cells with DNA damage undergo apoptosis or cellular senescence if the damage cannot be repaired. Recent studies highlight that cellular senescence plays a major role in aging. However, age-associated diseases, including emphysema and neurodegenerative disorders, are caused by apoptosis of lung alveolar epithelial cells and neurons, respectively. Therefore, enhanced apoptosis also promotes aging and shortens the life span depending on the cell type. Recently, we reported that ku70(-) (/) (-)bax(-) (/) (-) and ku70(-) (/) (-)bax(+/) (-) mice showed significantly extended life span in comparison with ku70(-) (/) (-)bax(+/+) mice. Ku70 is essential for non-homologous end joining pathway for DNA double strand break repair, and Bax plays an important role in apoptosis. Our study suggests that Bax-induced apoptosis has a significant impact on shortening the life span of ku70(-) (/) (-) mice, which are defective in one of DNA repair pathways. The lung alveolar space gradually enlarges during aging, both in mouse and human, and this age-dependent change results in the decrease of respiration capacity during aging that can lead to emphysema in more severe cases. We found that emphysema occurred in ku70(-) (/) (-) mice at the age of three-months old, and that Bax deficiency was able to suppress it. These results suggest that Bax-mediated apoptosis induces emphysema in ku70(-) (/) (-) mice. We also found that the number of cells, including bronchiolar epithelial cells and type 2 alveolar epithelial cells, shows a higher DNA double strand break damage response in ku70 KO mouse lung than in wild type. Recent studies suggest that non-homologous end joining activity decreases with increased age in mouse and rat model. Together, we hypothesize that the decline of Ku70-dependent DNA repair activity in lung alveolar epithelial cells is one of the causes of age-dependent decline of lung function resulting from excess Bax-mediated apoptosis of lung alveolar epithelial cells (and their

  1. Reduction of DNA mismatch repair protein expression in airway epithelial cells of premenopausal women chronically exposed to biomass smoke.

    PubMed

    Mukherjee, Bidisha; Dutta, Anindita; Chowdhury, Saswati; Roychoudhury, Sanghita; Ray, Manas Ranjan

    2014-02-01

    Biomass burning is a major source of indoor air pollution in rural India. This study examined whether chronic inhalation of biomass smoke causes change in the DNA mismatch repair (MMR) pathway in the airway cells. For this, airway cells exfoliated in sputum were collected from 72 premenopausal nonsmoking rural women (median age 34 years) who cooked with biomass (wood, dung, crop residues) and 68 control women who cooked with cleaner fuel liquefied petroleum gas (LPG) for the past 5 years or more. The levels of particulate matters with diameters less than 10 and 2.5 μm (PM10 and PM2.5) in indoor air were measured by real-time aerosol monitor. Benzene exposure was monitored by measuring trans,trans-muconic acid (t,t-MA) in urine by high-performance liquid chromatography with ultraviolet detector. Generation of reactive oxygen species (ROS) and level of superoxide dismutase (SOD) in airway cells were measured by flow cytometry and spectrophotometry, respectively. Immunocytochemical assay revealed lower percentage of airway epithelial cells expressing MMR proteins mutL homolog 1 (MLH1) and mutS homolog 2 (MSH2) in biomass-using women compared to LPG-using controls. Women who cooked with biomass had 6.7 times higher level of urinary t,t-MA, twofold increase in ROS generation, and 31 % depletion of SOD. Indoor air of biomass-using households had three times more particulate matters than that of controls. ROS, urinary t,t-MA, and particulate pollution in biomass-using kitchen had negative correlation, while SOD showed positive correlation with MSH2 and MLH1 expression. It appears that chronic exposure to biomass smoke reduces MMR response in airway epithelial cells, and oxidative stress plays an important role in the process. PMID:24146321

  2. Retinal pigment epithelial cell multinucleation in the aging eye - a mechanism to repair damage and maintain homoeostasis.

    PubMed

    Chen, Mei; Rajapakse, Dinusha; Fraczek, Monika; Luo, Chang; Forrester, John V; Xu, Heping

    2016-06-01

    Retinal pigment epithelial (RPE) cells are central to retinal health and homoeostasis. Dysfunction or death of RPE cells underlies many age-related retinal degenerative disorders particularly age-related macular degeneration. During aging RPE cells decline in number, suggesting an age-dependent cell loss. RPE cells are considered to be postmitotic, and how they repair damage during aging remains poorly defined. We show that RPE cells increase in size and become multinucleate during aging in C57BL/6J mice. Multinucleation appeared not to be due to cell fusion, but to incomplete cell division, that is failure of cytokinesis. Interestingly, the phagocytic activity of multinucleate RPE cells was not different from that of mononuclear RPE cells. Furthermore, exposure of RPE cells in vitro to photoreceptor outer segment (POS), particularly oxidized POS, dose-dependently promoted multinucleation and suppressed cell proliferation. Both failure of cytokinesis and suppression of proliferation required contact with POS. Exposure to POS also induced reactive oxygen species and DNA oxidation in RPE cells. We propose that RPE cells have the potential to proliferate in vivo and to repair defects in the monolayer. We further propose that the conventionally accepted 'postmitotic' status of RPE cells is due to a modified form of contact inhibition mediated by POS and that RPE cells are released from this state when contact with POS is lost. This is seen in long-standing rhegmatogenous retinal detachment as overtly proliferating RPE cells (proliferative vitreoretinopathy) and more subtly as multinucleation during normal aging. Age-related oxidative stress may promote failure of cytokinesis and multinucleation in RPE cells. PMID:26875723

  3. Contributions of DNA repair, cell cycle checkpoints and cell death to suppressing the DNA damage-induced tumorigenic behavior of Drosophila epithelial cells.

    PubMed

    Dekanty, A; Barrio, L; Milán, M

    2015-02-19

    When exposed to DNA-damaging agents, components of the DNA damage response (DDR) pathway trigger apoptosis, cell cycle arrest and DNA repair. Although failures in this pathway are associated with cancer development, the tumor suppressor roles of cell cycle arrest and apoptosis have recently been questioned in mouse models. Using Drosophila epithelial cells that are unable to activate the apoptotic program, we provide evidence that ionizing radiation (IR)-induced DNA damage elicits a tumorigenic behavior in terms of E-cadherin delocalization, cell delamination, basement membrane degradation and neoplasic overgrowth. The tumorigenic response of the tissue to IR is enhanced by depletion of Okra/DmRAD54 or spnA/DmRAD51--genes required for homologous recombination (HR) repair of DNA double-strand breaks in G2--and it is independent of the activity of Lig4, a ligase required for nonhomologous end-joining repair in G1. Remarkably, depletion of Grapes/DmChk1 or Mei-41/dATR-genes affecting DNA damage-induced cell cycle arrest in G2--compromised DNA repair and enhanced the tumorigenic response of the tissue to IR. On the contrary, DDR-independent lengthening of G2 had a positive impact on the dynamics of DNA repair and suppressed the tumorigenic response of the tissue to IR. Our results support a tumor suppressor role of apoptosis, DNA repair by HR and cell cycle arrest in G2 in simple epithelia subject to IR-induced DNA damage. PMID:24632609

  4. Epithelial hyperplasia, alveoli —

    Cancer.gov

    Solitary or multiple foci of increased cellularity distal to terminal bronchioles. The background of broncho-alveolar architecture remains detectable, and epithelial cells are usually single layered. Round to oval hypertrophic type II pneumocytes with abundant eosinophilic cytoplasm line alveolar walls. In bronchiolar subvariant, also called bronchiolization of alveoli, alveolar walls are lined by cuboidal to columnar cells with features of bronchiolar differentiation, such as formation of cilia, Clara cell resemblance, and presence of mucous granules. Foci of consolidation may indicate early stages of adenoma formation. Macrophages may be present in the alveolar lumens.

  5. Pulmonary administration of phosphoinositide 3-kinase inhibitor is a curative treatment for chronic obstructive pulmonary disease by alveolar regeneration.

    PubMed

    Horiguchi, Michiko; Oiso, Yuki; Sakai, Hitomi; Motomura, Tomoki; Yamashita, Chikamasa

    2015-09-10

    Chronic obstructive pulmonary disease (COPD) is an intractable pulmonary disease, causing widespread and irreversible alveoli collapse. The discovery of a low-molecular-weight compound that induces regeneration of pulmonary alveoli is of utmost urgency to cure intractable pulmonary diseases such as COPD. However, a practically useful compound for regenerating pulmonary alveoli is yet to be reported. Previously, we have elucidated that Akt phosphorylation is involved in a differentiation-inducing molecular mechanism of human alveolar epithelial stem cells, which play a role in regenerating pulmonary alveoli. In the present study, we directed our attention to phosphoinositide 3-kinase (PI3K)-Akt signaling and examined whether PI3K inhibitors display the pulmonary alveolus regeneration. Three PI3K inhibitors with different PI3K subtype specificities (Wortmannin, AS605240, PIK-75 hydrochloride) were tested for the differentiation-inducing effect on human alveolar epithelial stem cells, and Wortmannin demonstrated the most potent differentiation-inducing activity. We evaluated Akt phosphorylation in pulmonary tissues of an elastase-induced murine COPD model and found that Akt phosphorylation in the pulmonary tissue was enhanced in the murine COPD model compared with normal mice. Then, the alveolus-repairing effect of pulmonary administration of Wortmannin to murine COPD model was evaluated using X-ray CT analysis and hematoxylin-eosin staining. As a result, alveolar damages were repaired in the Wortmannin-administered group to a similar level of normal mice. Furthermore, pulmonary administration of Wortmannin induced a significant recovery of the respiratory function, compared to the control group. These results indicate that Wortmannin is capable of inducing differentiation of human alveolar epithelial stem cells and represents a promising drug candidate for curative treatment of pulmonary alveolar destruction in COPD. PMID:26160307

  6. Downregulation of the cancer susceptibility protein WRAP53β in epithelial ovarian cancer leads to defective DNA repair and poor clinical outcome

    PubMed Central

    Hedström, E; Pederiva, C; Farnebo, J; Nodin, B; Jirström, K; Brennan, D J; Farnebo, M

    2015-01-01

    Alterations in the scaffold protein WRAP53β have previously been linked to carcinogenesis and, in particular, associated with an increased risk for epithelial ovarian cancer. Here, we investigated the pathogenic impact and prognostic significance of WRAP53β in connection with epithelial ovarian cancer and examined the underlying mechanisms. We find that reduced expression of WRAP53β in ovarian tumors correlated with attenuated DNA damage response and poor patient survival. Furthermore, in ovarian cancer cell lines, WRAP53β was rapidly recruited to DNA double-strand breaks, where it orchestrated the recruitment of repair factors involved in homologous recombination and non-homologous end joining, including RNF168, 53BP1, BRCA1 and RAD51. Mechanistically, WRAP53β accomplishes this by facilitating the necessary ubiquitinylation at DNA breaks. Finally, we demonstrate that loss of WRAP53β significantly impairs the repair of DNA double-strand breaks, resulting in their accumulation. Our findings establish WRAP53β as a regulator of homologous recombination and non-homologous end joining repair in ovarian cancer cells, suggesting that loss of this protein contributes to the development and/or progression of ovarian tumors. Moreover, our current observations identify the nuclear levels of WRAP53β as a promising biomarker for the survival of patients with ovarian cancer. PMID:26426684

  7. Alveolar Development and Disease

    PubMed Central

    Weaver, Timothy E.

    2015-01-01

    Gas exchange after birth is entirely dependent on the remarkable architecture of the alveolus, its formation and function being mediated by the interactions of numerous cell types whose precise positions and activities are controlled by a diversity of signaling and transcriptional networks. In the later stages of gestation, alveolar epithelial cells lining the peripheral lung saccules produce increasing amounts of surfactant lipids and proteins that are secreted into the airspaces at birth. The lack of lung maturation and the associated lack of pulmonary surfactant in preterm infants causes respiratory distress syndrome, a common cause of morbidity and mortality associated with premature birth. At the time of birth, surfactant homeostasis begins to be established by balanced processes involved in surfactant production, storage, secretion, recycling, and catabolism. Insights from physiology and engineering made in the 20th century enabled survival of newborn infants requiring mechanical ventilation for the first time. Thereafter, advances in biochemistry, biophysics, and molecular biology led to an understanding of the pulmonary surfactant system that made possible exogenous surfactant replacement for the treatment of preterm infants. Identification of surfactant proteins, cloning of the genes encoding them, and elucidation of their roles in the regulation of surfactant synthesis, structure, and function have provided increasing understanding of alveolar homeostasis in health and disease. This Perspective seeks to consider developmental aspects of the pulmonary surfactant system and its importance in the pathogenesis of acute and chronic lung diseases related to alveolar homeostasis. PMID:25932959

  8. Alveolar development and disease.

    PubMed

    Whitsett, Jeffrey A; Weaver, Timothy E

    2015-07-01

    Gas exchange after birth is entirely dependent on the remarkable architecture of the alveolus, its formation and function being mediated by the interactions of numerous cell types whose precise positions and activities are controlled by a diversity of signaling and transcriptional networks. In the later stages of gestation, alveolar epithelial cells lining the peripheral lung saccules produce increasing amounts of surfactant lipids and proteins that are secreted into the airspaces at birth. The lack of lung maturation and the associated lack of pulmonary surfactant in preterm infants causes respiratory distress syndrome, a common cause of morbidity and mortality associated with premature birth. At the time of birth, surfactant homeostasis begins to be established by balanced processes involved in surfactant production, storage, secretion, recycling, and catabolism. Insights from physiology and engineering made in the 20th century enabled survival of newborn infants requiring mechanical ventilation for the first time. Thereafter, advances in biochemistry, biophysics, and molecular biology led to an understanding of the pulmonary surfactant system that made possible exogenous surfactant replacement for the treatment of preterm infants. Identification of surfactant proteins, cloning of the genes encoding them, and elucidation of their roles in the regulation of surfactant synthesis, structure, and function have provided increasing understanding of alveolar homeostasis in health and disease. This Perspective seeks to consider developmental aspects of the pulmonary surfactant system and its importance in the pathogenesis of acute and chronic lung diseases related to alveolar homeostasis. PMID:25932959

  9. Isolation and Quantitative Estimation of Diesel Exhaust and Carbon Black Particles Ingested by Lung Epithelial Cells and Alveolar Macrophages In Vitro

    EPA Science Inventory

    A new procedure for isolating and estimating ingested carbonaceous diesel exhaust particles (DEP) or carbon black (CB) particles by lung epithelial cells and macrophages is described. Cells were incubated with DEP or CB to examine cell-particle interaction and ingestion. After va...

  10. Crocidolite activates NF-kappa B and MIP-2 gene expression in rat alveolar epithelial cells. Role of mitochondrial-derived oxidants.

    PubMed

    Driscoll, K E; Carter, J M; Howard, B W; Hassenbein, D; Janssen, Y M; Mossman, B T

    1998-10-01

    Nuclear factor kappa B (NF-kappa B) is a transcription factor that regulates expression of several genes coding for inflammatory and immunoregulatory proteins including the neutrophil chemotactic cytokine MIP-2. In previous studies we found that crocidolite asbestos activates the nuclear translocation of NF-kappa B as well as MIP-2 gene expression in rat alveolar type II cells. Here we report that both crocidolite-induced NF-kappa B activation of MIP-2 gene expression can be attenuated by the antioxidant tetramethylthiourea, suggesting the dependence of these responses on oxidative stress. Crocidolite exposure of RLE-TN cells also increased production of H2O2, a response that was inhibited by the mitochondrial respiratory chain inhibitor thenoyltrifluoroacetone (TTFA). TTFA treatment of RLE-6TN cells also inhibited crocidolite-induced nuclear translocation of NF-kappa B and MIP-2 gene expression. These results indicate crocidolite exposure of rat alveolar type II cells results in increased production of mitochondrial-derived hydrogen peroxide and that mitochondrial-derived oxidants contribute to crocidolite activation of NF-kappa B and increases in MIP-2 gene expression. PMID:9788893

  11. TRIM72 modulates caveolar endocytosis in repair of lung cells.

    PubMed

    Nagre, Nagaraja; Wang, Shaohua; Kellett, Thomas; Kanagasabai, Ragu; Deng, Jing; Nishi, Miyuki; Shilo, Konstantin; Oeckler, Richard A; Yalowich, Jack C; Takeshima, Hiroshi; Christman, John; Hubmayr, Rolf D; Zhao, Xiaoli

    2016-03-01

    Alveolar epithelial and endothelial cell injury is a major feature of the acute respiratory distress syndrome, in particular when in conjunction with ventilation therapies. Previously we showed [Kim SC, Kellett T, Wang S, Nishi M, Nagre N, Zhou B, Flodby P, Shilo K, Ghadiali SN, Takeshima H, Hubmayr RD, Zhao X. Am J Physiol Lung Cell Mol Physiol 307: L449-L459, 2014.] that tripartite motif protein 72 (TRIM72) is essential for amending alveolar epithelial cell injury. Here, we posit that TRIM72 improves cellular integrity through its interaction with caveolin 1 (Cav1). Our data show that, in primary type I alveolar epithelial cells, lack of TRIM72 led to significant reduction of Cav1 at the plasma membrane, accompanied by marked attenuation of caveolar endocytosis. Meanwhile, lentivirus-mediated overexpression of TRIM72 selectively increases caveolar endocytosis in rat lung epithelial cells, suggesting a functional association between these two. Further coimmunoprecipitation assays show that deletion of either functional domain of TRIM72, i.e., RING, B-box, coiled-coil, or PRY-SPRY, abolishes the physical interaction between TRIM72 and Cav1, suggesting that all theoretical domains of TRIM72 are required to forge a strong interaction between these two molecules. Moreover, in vivo studies showed that injurious ventilation-induced lung cell death was significantly increased in knockout (KO) TRIM72(KO) and Cav1(KO) lungs compared with wild-type controls and was particularly pronounced in double KO mutants. Apoptosis was accompanied by accentuation of gross lung injury manifestations in the TRIM72(KO) and Cav1(KO) mice. Our data show that TRIM72 directly and indirectly modulates caveolar endocytosis, an essential process involved in repair of lung epithelial cells through removal of plasma membrane wounds. Given TRIM72's role in endomembrane trafficking and cell repair, we consider this molecule an attractive therapeutic target for patients with injured lungs. PMID

  12. [Relationship between artesunate influence on the process of TGF-beta1 induced alveolar epithelial cells transform into mesenchymal cells and on idiopathic pulmonary fibrosis].

    PubMed

    Wang, Chang-Ming; Chen, Juan; Jiang, Ming; Xuan, Xiu-Ping; Li, Hong-Xiu

    2014-01-01

    This study is to investigate the effect of artesunate on transforming growth factor-beta1 (TGF-beta1) induced epithelial-mesenchymal transition (EMT) and its possible mechanism. After the in vitro cultured RLE-6TN cells were treated with TGF-beta1 then artesunate intervened on it, after 24 h, expression of the markers of mesenchymal cell was assayed using Western blotting and real-time PCR analysis. Western blotting was also used to detect the effect of TGF-beta1 on the Smad3 and Smad7 expressions of RLE-6TN cells. Morphological alterations were examined by phase-contrast microscope, and ultrastructure changes by electron microscope. Incubation of RLE-6TN cells with TGF-beta1 resulted in the up-regulation of the expression of the mesenchymal cell markers, after artesunate intervened on it, resulted in the down-regulation of the expression. Meanwhile, incubation with artesunate intervened on RLE-6TN cells could lead to the apparent down-regulation of the expression of Smad3 and up-regulation of Samd7 and the transition of RLE-6TN cells to mesenchymal-like by TGF-beta1 induction, after artesunate intervened on it, RLE-6TN cells to epithelial-like. TGF-beta1 induced epithelial-mesenchymal transition process; artesunate can inhibit TGF-beta1-induced epithelial-mesenchymal transition process, the possible mechanism is up-regulation of the expression of Smad7 and down-regulation of the expression of Smad3, meanwhile inhibits phosphorylation of Smad3. PMID:24783520

  13. Protective effect of Ac-SDKP on alveolar epithelial cells through inhibition of EMT via TGF-β1/ROCK1 pathway in silicosis in rat.

    PubMed

    Deng, Haijing; Xu, Hong; Zhang, Xianghong; Sun, Yue; Wang, Ruimin; Brann, Darrell; Yang, Fang

    2016-03-01

    The epithelial-mesenchymal transition (EMT) is a critical stage during the development of silicosis fibrosis. In the current study, we hypothesized that the anti-fibrotic tetrapeptide, N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) may exert its anti-fibrotic effects via activation of the TGF-β1/ROCK1 pathway, leading to inhibition of EMT. To address this hypothesis, we first examined the effect of Ac-SDKP upon EMT using an in vivo rat silicosis model, as well as in an in vitro model of TGF-β1-induced EMT. Confocal laser scanning microscopy was used to examine colocalization of surfactant protein A (SP-A), fibroblast specific protein-1 (FSP-1) and α-smooth muscle actin (α-SMA) in vivo. Western blot analysis was used to examine for changes in the protein levels of E-cadherin (E-cad) and SP-A (epithelial cell markers), vimentin (mesenchymal cell marker), α-SMA (active myofibroblast marker), and collagen I and III in both in vivo and in vitro experiments. Secondly, we utilized Western blot analysis and confocal laser scanning microscopy to examine the protein expression of TGF-β1 and ROCK1 in in vivo and in vitro studies. The results revealed that Ac-SDKP treatment prevented increases in the expression of mesenchymal markers as well as TGF-β1, ROCK1, collagen I and III. Furthermore, Ac-SDKP treatment prevented decreases in the expression of epithelial cell markers in both in vivo and in vitro experiments. Based on the results, we conclude that Ac-SDKP inhibits the transition of epithelial cell-myofibroblast in silicosis via activation of the TGF-β1/ROCK1 signaling pathway, which may serve as a novel mechanism by which it exerts its anti-fibrosis properties. PMID:26785300

  14. Sessile alveolar macrophages communicate with alveolar epithelium to modulate immunity.

    PubMed

    Westphalen, Kristin; Gusarova, Galina A; Islam, Mohammad N; Subramanian, Manikandan; Cohen, Taylor S; Prince, Alice S; Bhattacharya, Jahar

    2014-02-27

    The tissue-resident macrophages of barrier organs constitute the first line of defence against pathogens at the systemic interface with the ambient environment. In the lung, resident alveolar macrophages (AMs) provide a sentinel function against inhaled pathogens. Bacterial constituents ligate Toll-like receptors (TLRs) on AMs, causing AMs to secrete proinflammatory cytokines that activate alveolar epithelial receptors, leading to recruitment of neutrophils that engulf pathogens. Because the AM-induced response could itself cause tissue injury, it is unclear how AMs modulate the response to prevent injury. Here, using real-time alveolar imaging in situ, we show that a subset of AMs attached to the alveolar wall form connexin 43 (Cx43)-containing gap junction channels with the epithelium. During lipopolysaccharide-induced inflammation, the AMs remained sessile and attached to the alveoli, and they established intercommunication through synchronized Ca(2+) waves, using the epithelium as the conducting pathway. The intercommunication was immunosuppressive, involving Ca(2+)-dependent activation of Akt, because AM-specific knockout of Cx43 enhanced alveolar neutrophil recruitment and secretion of proinflammatory cytokines in the bronchoalveolar lavage. A picture emerges of a novel immunomodulatory process in which a subset of alveolus-attached AMs intercommunicates immunosuppressive signals to reduce endotoxin-induced lung inflammation. PMID:24463523

  15. Sessile alveolar macrophages communicate with alveolar epithelium to modulate immunity

    NASA Astrophysics Data System (ADS)

    Westphalen, Kristin; Gusarova, Galina A.; Islam, Mohammad N.; Subramanian, Manikandan; Cohen, Taylor S.; Prince, Alice S.; Bhattacharya, Jahar

    2014-02-01

    The tissue-resident macrophages of barrier organs constitute the first line of defence against pathogens at the systemic interface with the ambient environment. In the lung, resident alveolar macrophages (AMs) provide a sentinel function against inhaled pathogens. Bacterial constituents ligate Toll-like receptors (TLRs) on AMs, causing AMs to secrete proinflammatory cytokines that activate alveolar epithelial receptors, leading to recruitment of neutrophils that engulf pathogens. Because the AM-induced response could itself cause tissue injury, it is unclear how AMs modulate the response to prevent injury. Here, using real-time alveolar imaging in situ, we show that a subset of AMs attached to the alveolar wall form connexin 43 (Cx43)-containing gap junction channels with the epithelium. During lipopolysaccharide-induced inflammation, the AMs remained sessile and attached to the alveoli, and they established intercommunication through synchronized Ca2+ waves, using the epithelium as the conducting pathway. The intercommunication was immunosuppressive, involving Ca2+-dependent activation of Akt, because AM-specific knockout of Cx43 enhanced alveolar neutrophil recruitment and secretion of proinflammatory cytokines in the bronchoalveolar lavage. A picture emerges of a novel immunomodulatory process in which a subset of alveolus-attached AMs intercommunicates immunosuppressive signals to reduce endotoxin-induced lung inflammation.

  16. Expression of Carcinoembryonic Cell Adhesion Molecule 6 and Alveolar Epithelial Cell Markers in Lungs of Human Infants with Chronic Lung Disease.

    PubMed

    Gonzales, Linda W; Gonzalez, Robert; Barrette, Anne Marie; Wang, Ping; Dobbs, Leland; Ballard, Philip L

    2015-12-01

    The membrane protein carcinoembryonic antigen cell adhesion molecule (CEACAM6) is expressed in the epithelium of various tissues, participating in innate immune defense, cell proliferation and differentiation, with overexpression in gastrointestinal tract, pancreatic and lung tumors. It is developmentally and hormonally regulated in fetal human lung, with an apparent increased production in preterm infants with respiratory failure. To further examine the expression and cell localization of CEACAM6, we performed immunohistochemical and biochemical studies in lung specimens from infants with and without chronic lung disease. CEACAM6 protein and mRNA were increased ~4-fold in lungs from infants with chronic lung disease as compared with controls. By immunostaining, CEACAM6 expression was markedly increased in the lung parenchyma of infants and children with a variety of chronic lung disorders, localizing to hyperplastic epithelial cells with a ~7-fold elevated proliferative rate by PCNA staining. Some of these cells also co-expressed membrane markers of both type I and type II cells, which is not observed in normal postnatal lung, suggesting they are transitional epithelial cells. We suggest that CEACAM6 is both a marker of lung epithelial progenitor cells and a contributor to the proliferative response after injury due to its anti-apoptotic and cell adhesive properties. PMID:26374831

  17. DA-Raf-Mediated Suppression of the Ras—ERK Pathway Is Essential for TGF-β1-Induced Epithelial—Mesenchymal Transition in Alveolar Epithelial Type 2 Cells

    PubMed Central

    Watanabe-Takano, Haruko; Takano, Kazunori; Hatano, Masahiko; Tokuhisa, Takeshi; Endo, Takeshi

    2015-01-01

    Myofibroblasts play critical roles in the development of idiopathic pulmonary fibrosis by depositing components of extracellular matrix. One source of lung myofibroblasts is thought to be alveolar epithelial type 2 cells that undergo epithelial–mesenchymal transition (EMT). Rat RLE-6TN alveolar epithelial type 2 cells treated with transforming growth factor-β1 (TGF-β1) are converted into myofibroblasts through EMT. TGF-β induces both canonical Smad signaling and non-canonical signaling, including the Ras-induced ERK pathway (Raf–MEK–ERK). However, the signaling mechanisms regulating TGF-β1-induced EMT are not fully understood. Here, we show that the Ras–ERK pathway negatively regulates TGF-β1-induced EMT in RLE-6TN cells and that DA-Raf1 (DA-Raf), a splicing isoform of A-Raf and a dominant-negative antagonist of the Ras–ERK pathway, plays an essential role in EMT. Stimulation of the cells with fibroblast growth factor 2 (FGF2), which activated the ERK pathway, prominently suppressed TGF-β1-induced EMT. An inhibitor of MEK, but not an inhibitor of phosphatidylinositol 3-kinase, rescued the TGF-β1-treated cells from the suppression of EMT by FGF2. Overexpression of a constitutively active mutant of a component of the Ras–ERK pathway, i.e., H-Ras, B-Raf, or MEK1, interfered with EMT. Knockdown of DA-Raf expression with siRNAs facilitated the activity of MEK and ERK, which were only weakly and transiently activated by TGF-β1. Although DA-Raf knockdown abrogated TGF-β1-induced EMT, the abrogation of EMT was reversed by the addition of the MEK inhibitor. Furthermore, DA-Raf knockdown impaired the TGF-β1-induced nuclear translocation of Smad2, which mediates the transcription required for EMT. These results imply that intrinsic DA-Raf exerts essential functions for EMT by antagonizing the TGF-β1-induced Ras–ERK pathway in RLE-6TN cells. PMID:25996975

  18. Activation of canonical wnt pathway promotes differentiation of mouse bone marrow-derived MSCs into type II alveolar epithelial cells, confers resistance to oxidative stress, and promotes their migration to injured lung tissue in vitro.

    PubMed

    Liu, Ai-Ran; Liu, Le; Chen, Song; Yang, Yi; Zhao, Hong-Jie; Liu, Ling; Guo, Feng-Mei; Lu, Xiao-Min; Qiu, Hai-Bo

    2013-06-01

    The differentiation of mesenchymal stem cells (MSCs) into type II alveolar epithelial (AT II) cells in vivo and in vitro, is critical for reepithelization and recovery in acute lung injury (ALI), but the mechanisms responsible for differentiation are unclear. In the present study, we investigated the role of the canonical wnt pathway in the differentiation of mouse bone marrow-derived MSCs (mMSCs) into AT II cells. Using a modified co-culture system with murine lung epithelial-12 (MLE-12) cells and small airway growth media (SAGM) to efficiently drive mMSCs differentiation, we found that GSK 3β and β-catenin in the canonical wnt pathway were up-regulated during differentiation. The levels of surfactant protein (SP) C, SPB, and SPD, the specific markers of AT II cells, correspondingly increased in mMSCs when Wnt3a or LiCl was added to the co-culture system to activate wnt/β-catenin signaling. The expression of these factors was depressed to some extent by inhibiting the pathway with the addition of DKK 1. The differentiation rate of mMSCs also depends on their abilities to accumulate and survive in inflammatory tissue. Our results suggested that the activation of wnt/β-catenin signaling promoted mMSCs migration towards ALI mouse-derived lung tissue in a Transwell assay, and ameliorated the cell death and the reduction of Bcl-2/Bax induced by H(2) O(2), which simultaneously caused reduced GSK 3β and β-catenin in mMSCs. These data supports a potential mechanism for the differentiation of mMSCs into AT II cells involving canonical wnt pathway activation, which may be significant to their application in ALI. PMID:23154940

  19. Inflammatory and Oxidative Stress Responses of an Alveolar Epithelial Cell Line to Airborne Zinc Oxide Nanoparticles at the Air-Liquid Interface: A Comparison with Conventional, Submerged Cell-Culture Conditions

    PubMed Central

    Lenz, Anke-Gabriele; Karg, Erwin; Brendel, Ellen; Hinze-Heyn, Helga; Maier, Konrad L.; Eickelberg, Oliver; Stoeger, Tobias; Schmid, Otmar

    2013-01-01

    The biological effects of inhalable nanoparticles have been widely studied in vitro with pulmonary cells cultured under submerged and air-liquid interface (ALI) conditions. Submerged exposures are experimentally simpler, but ALI exposures are physiologically more realistic and hence potentially biologically more meaningful. In this study, we investigated the cellular response of human alveolar epithelial-like cells (A549) to airborne agglomerates of zinc oxide (ZnO) nanoparticles at the ALI, compared it to the response under submerged culture conditions, and provided a quantitative comparison with the literature data on different types of particles and cells. For ZnO nanoparticle doses of 0.7 and 2.5 μg ZnO/cm2 (or 0.09 and 0.33 cm2 ZnO/cm2), cell viability was not mitigated and no significant effects on the transcript levels of oxidative stress markers (HMOX1, SOD-2 and GCS) were observed. However, the transcript levels of proinflammatory markers (IL-8, IL-6, and GM-CSF) were induced to higher levels under ALI conditions. This is consistent with the literature data and it suggests that in vitro toxicity screening of nanoparticles with ALI cell culture systems may produce less false negative results than screening with submerged cell cultures. However, the database is currently too scarce to draw a definite conclusion on this issue. PMID:23484138

  20. Differences in the expression of chromosome 1 genes between lung telocytes and other cells: mesenchymal stem cells, fibroblasts, alveolar type II cells, airway epithelial cells and lymphocytes

    PubMed Central

    Sun, Xiaoru; Zheng, Minghuan; Zhang, Miaomiao; Qian, Mengjia; Zheng, Yonghua; Li, Meiyi; Cretoiu, Dragos; Chen, Chengshui; Chen, Luonan; Popescu, Laurentiu M; Wang, Xiangdong

    2014-01-01

    Telocytes (TCs) are a unique type of interstitial cells with specific, extremely long prolongations named telopodes (Tps). Our previous study showed that TCs are distinct from fibroblasts (Fbs) and mesenchymal stem cells (MSCs) as concerns gene expression and proteomics. The present study explores patterns of mouse TC-specific gene profiles on chromosome 1. We investigated the network of main genes and the potential functional correlations. We compared gene expression profiles of mouse pulmonary TCs, MSCs, Fbs, alveolar type II cells (ATII), airway basal cells (ABCs), proximal airway cells (PACs), CD8+ T cells from bronchial lymph nodes (T-BL) and CD8+ T cells from lungs (T-LL). The functional and feature networks were identified and compared by bioinformatics tools. Our data showed that on TC chromosome 1, there are about 25% up-regulated and 70% down-regulated genes (more than onefold) as compared with the other cells respectively. Capn2, Fhl2 and Qsox1 were over-expressed in TCs compared to the other cells, indicating that biological functions of TCs are mainly associated with morphogenesis and local tissue homoeostasis. TCs seem to have important roles in the prevention of tissue inflammation and fibrogenesis development in lung inflammatory diseases and as modulators of immune cell response. In conclusion, TCs are distinct from the other cell types. PMID:24826900

  1. The modality of cell-particle interactions drives the toxicity of nanosized CuO and TiO₂ in human alveolar epithelial cells.

    PubMed

    Moschini, Elisa; Gualtieri, Maurizio; Colombo, Miriam; Fascio, Umberto; Camatini, Marina; Mantecca, Paride

    2013-10-24

    Metal oxide NPs are abundantly produced in nanotech industries and are emitted in several combustion processes, suggesting the need to characterize their toxic impact on the human respiratory system. The acute toxicity and the morphological changes induced by copper oxide and titanium dioxide NPs (nCuO and nTiO₂) on the human alveolar cell line A549 are here investigated. Cell viability and oxidative stress have been studied in parallel with NP internalization and cell ultrastructural modifications. TiO₂ NPs were abundantly internalized by cells through the endocytic pathway, even they did not induce cell death and ultrastructural lesions. Only after 24h cells were affected by an abundant NP internalization presenting a consequent altered morphology. High cytotoxicity, oxidative stress and severe ultrastructural damages were produced by nCuO, since cell membrane and mitochondria resulted to be heavily affected, even at early exposure time. nCuO-induced toxicity has been interpreted as a consequence of both NPs reactivity and copper ions dissolution in lysosomal compartments, even the free NPs, scattered throughout all the cell compartments, might contribute to the toxicity. The antioxidant N-acetylcysteine was effective in recovering nCuO exposed cells viability and Bafilomycin A1 inhibited copper ions release in phagolysosomes and significantly rescued cells, suggesting a relevant cytotoxic mechanism relative to oxidative damages and authophagic cell death, together with NP internalization and dissolution. Our results support the previous data reporting CuO NPs are highly cytotoxic and genotoxic, and associate their toxic effects with their cell penetration and interaction with various compartments. In conclusion, the so-called "Trojan horse" mechanism and autophagy, are involved in nCuO-induced cell death, even a further research is needed to explain the events occurring at early exposure time. PMID:23906720

  2. Temporal Transcriptional Response during Infection of Type II Alveolar Epithelial Cells with Francisella tularensis Live Vaccine Strain (LVS) Supports a General Host Suppression and Bacterial Uptake by Macropinocytosis*

    PubMed Central

    Bradburne, Christopher E.; Verhoeven, Anne B.; Manyam, Ganiraju C.; Chaudhry, Saira A.; Chang, Eddie L.; Thach, Dzung C.; Bailey, Charles L.; van Hoek, Monique L.

    2013-01-01

    Pneumonic tularemia is caused by inhalation of Francisella tularensis, one of the most infectious microbes known. We wanted to study the kinetics of the initial and early interactions between bacterium and host cells in the lung. To do this, we examined the infection of A549 airway epithelial cells with the live vaccine strain (LVS) of F. tularensis. A549 cells were infected and analyzed for global transcriptional response at multiple time points up to 16 h following infection. At 15 min and 2 h, a strong transcriptional response was observed including cytoskeletal rearrangement, intracellular transport, and interferon signaling. However, at later time points (6 and 16 h), very little differential gene expression was observed, indicating a general suppression of the host response consistent with other reported cell lines and murine tissues. Genes for macropinocytosis and actin/cytoskeleton rearrangement were highly up-regulated and common to the 15 min and 2 h time points, suggesting the use of this method for bacterial entry into cells. We demonstrate macropinocytosis through the uptake of FITC-dextran and amiloride inhibition of Francisella LVS uptake. Our results suggest that macropinocytosis is a potential mechanism of intracellular entry by LVS and that the host cell response is suppressed during the first 2–6 h of infection. These results suggest that the attenuated Francisella LVS induces significant host cell signaling at very early time points after the bacteria's interaction with the cell. PMID:23322778

  3. Collagen based film with well epithelial and stromal regeneration as corneal repair materials: Improving mechanical property by crosslinking with citric acid.

    PubMed

    Zhao, Xuan; Liu, Yang; Li, Weichang; Long, Kai; Wang, Lin; Liu, Sa; Wang, Yingjun; Ren, Li

    2015-10-01

    Corneal disease can lead to vision loss. It has become the second greatest cause of blindness in the world, and keratoplasty is considered as an effective treatment method. This paper presents the crosslinked collagen (Col)-citric acid (CA) films developed by making use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The results showed that the Col-CA films had necessary optical performance, water content. The collagenase resistance of CA crosslinked films was superior to that of EDC crosslinked films. And CA5 film (Col:CA:EDC:NHS=60:3:10:10) had the best mechanical properties. Cell experiments showed that CA5 film was non-cytotoxic and human corneal epithelial cells could proliferate well on the films. Lamellar keratoplasty showed that the CA5 film could be sutured in the rabbit eyes and was epithelialized completely in about 10 days, and the transparency was restored quickly in 30±5 days. No inflammation and corneal neovascularization were observed at 6 months. Corneal stroma had been repaired; stromal cells and neo-stroma could be seen in the area of operation from the hematoxylin-eosin stained histologic sections and anterior segment optical coherence tomography images. These results indicated that Col-CA films were highly promising biomaterials that could be used in corneal tissue engineering and a variety of other tissue engineering applications. PMID:26117756

  4. Management of the alveolar cleft.

    PubMed

    Santiago, Pedro E; Schuster, Lindsay A; Levy-Bercowski, Daniel

    2014-04-01

    Orthopedic and orthodontic management of patients born with clefts of the lip, alveolus and palate is based on the application of basic biomechanical principles adapted to the individualized cleft anatomy. This article focuses on orthopedic and orthodontic preparation for 2 stages of interdisciplinary orthodontic/surgical cleft care: presurgical infant orthopedics (nasoalveolar molding) for lip/alveolus/nasal surgical repair and maxillary arch preparation for secondary alveolar bone grafting. These preparatory stages of orthopedic/orthodontic therapy are undertaken with the goal of restoring normal anatomic relationships to assist the surgeon in providing the best possible surgical care. PMID:24607190

  5. Correction of alveolar cleft with calcium-based bone substitutes.

    PubMed

    Lazarou, Spiros A; Contodimos, George B; Gkegkes, Ioannis D

    2011-05-01

    The criterion standard of alveolar cleft repair is iliac crest bone graft before secondary canine eruption. Tooth eruption has never been shown to occur in synthetic bone substitute, and there is no ideal autologous bone graft for primary repair. This prospective study evaluated alveolar cleft grafting with a calcium substitute before primary canine eruption. Ten consecutive patients with complete cleft lip, palate, and unilateral alveolar cleft with reasonably aligned arches were grafted beginning in January 2003 to March 2007. Mean age at surgery was 10.4 months. Follow-up ranged from 3 to 7 years. Radiologic evaluation of alveolar ridge was performed at the age of 4.All 10 patients were operated on by the same surgeon using the same technique, that is, conservative elevation of nasal, oral, and anterior alveolar mucosal flaps around the cleft, closure of nasal and oral flaps, placement of 1 to 3 mL of calcium substitute paste or crystals in the pocket, and closure of the anterior alveolar mucosa. All 10 patients healed without complication. Clinical evaluation revealed a well-healed arch with primary canine growth in the area of the previous cleft. Adequate normal bone formation and often a descending secondary canine were radiologically confirmed. Calcium substitutes offer significant advantages over other biomaterials as well as autologous bone grafts particularly in the primary alveolar cleft reconstruction. Our study has shown for the first time that teeth can erupt through this material, which turns into a normal functioning bone in the alveolar ridge. PMID:21558929

  6. Isolation and Culture of Human Alveolar Type II Pneumocytes.

    PubMed

    Witherden, I R; Tetley, T D

    2001-01-01

    Alveolar type II pneumocytes (alveolar type II cells; TII cells) play an important role in the homeostasis of the alveolar unit. They are the progenitor cells to the type I pneumocyte and are therefore responsible for regeneration of alveolar epithelium following alveolar epithelial cell damage. The type I cell covers over 90% of the alveolar surface, reflecting its capacity to stretch into a flattened cell with very little depth (approx. 0.1 µm), but with a large surface area, to facilitate gas exchange. Nevertheless, the type II cell outnumbers type I cells, estimated to be by 2:1 in rodents. Most of the type II cell lies buried in the interstitium of the alveolus, with only the apical tip of the cell reaching into the airspace, through which another crucial function, provision of alveolar surfactant, occurs. Surfactant synthesis and secretion is a unique feature of type II cells; surfactant consists of a high proportion of phospholipids (approx. 90%) and a small proportion of protein (approx. 10%), which contains surfactant apoprotein (SP), of which four have so far been described, SP-A, SP-B, SP-C, and SP-D (1,2). Surfactant is highly surface active and is essential to prevent alveolar collapse. In addition, surfactant has many other roles, including pulmonary host defense. Compromised surfactant synthesis and function are believed to be a feature of numerous disease states (1,2), including infant respiratory distress syndrome, adult respiratory distress syndrome, alveolar proteinosis, and microbial infection. PMID:21336897

  7. Alveolar-cell carcinoma: a problem in sputum cytodiagnosis.

    PubMed Central

    Spriggs, A I; Cole, M; Dunnill, M S

    1982-01-01

    Cytology and histology are correlated in a series of 22 cases chosen to illustrate the differential diagnosis between clusters of benign bronchial or bronchiolar cells seen in sputum, and those of alveolar cell carcinoma or adenocarcinoma with alveolar spread. Alveolar-cell carcinoma is characterised by clusters of small epithelial cells in spherical or irregular formations, none showing enough polarity to distinguish a smooth or palisaded surface. The appearances are most distinctive if vacuolation is absent. The diagnosis cannot, however, be confidently made in all cases from morphological features of cells in sputum. Images PMID:6294147

  8. Pulmonary administration of 1,25-dihydroxyvitamin D3 to the lungs induces alveolar regeneration in a mouse model of chronic obstructive pulmonary disease.

    PubMed

    Horiguchi, Michiko; Hirokawa, Mai; Abe, Kaori; Kumagai, Harumi; Yamashita, Chikamasa

    2016-07-10

    Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disease with several causes, including smoking, and no curative therapeutic agent is available, particularly for destructive alveolar lesions. In this study, we investigated the differentiation-inducing effect on undifferentiated lung cells (Calu-6) and the alveolar regenerative effect of the active vitamin 1,25-dihydroxy vitamin D3 (VD3) with the ultimate goal of developing a novel curative drug for COPD. First, the differentiation-inducing effect of VD3 on Calu-6 cells was evaluated. Treatment with VD3 increased the proportions of type I alveolar epithelial (AT-I) and type II alveolar epithelial (AT-II) cells constituting alveoli in a concentration- and treatment time-dependent manner, demonstrating the potent differentiation-inducing activity of VD3 on Calu-6 cells. We thus administered VD3 topically to the mice lung using a previously developed intrapulmonary administration via self-inhalation method. To evaluate the alveolus-repairing effect of VD3, we administered VD3 intrapulmonarily to elastase-induced COPD model mice and computed the mean distance between the alveolar walls as an index of the extent of alveolar injury. Results showed significant decreases in the alveolar wall distance in groups of mice that received 0.01, 0.1, and 1μg/kg of intrapulmonary VD3, revealing excellent alveolus-regenerating effect of VD3. Furthermore, we evaluated the effect of VD3 on improving respiratory function using a respiratory function analyzer. Lung elasticity and respiratory competence [forced expiratory volume (FEV) 1 s %] are reduced in COPD, reflecting advanced emphysematous changes. In elastase-induced COPD model mice, although lung elasticity and respiratory competence were reduced, VD3 administered intrapulmonarily twice weekly for 2weeks recovered tissue elastance and forced expiratory volume in 0.05s to the forced vital capacity, which are indicators of lung elasticity and respiratory

  9. Stem cell therapy to protect and repair the developing brain: a review of mechanisms of action of cord blood and amnion epithelial derived cells

    PubMed Central

    Castillo-Melendez, Margie; Yawno, Tamara; Jenkin, Graham; Miller, Suzanne L.

    2013-01-01

    In the research, clinical, and wider community there is great interest in the use of stem cells to reduce the progression, or indeed repair brain injury. Perinatal brain injury may result from acute or chronic insults sustained during fetal development, during the process of birth, or in the newborn period. The most readily identifiable outcome of perinatal brain injury is cerebral palsy, however, this is just one consequence in a spectrum of mild to severe neurological deficits. As we review, there are now clinical trials taking place worldwide targeting cerebral palsy with stem cell therapies. It will likely be many years before strong evidence-based results emerge from these trials. With such trials underway, it is both appropriate and timely to address the physiological basis for the efficacy of stem-like cells in preventing damage to, or regenerating, the newborn brain. Appropriate experimental animal models are best placed to deliver this information. Cell availability, the potential for immunological rejection, ethical, and logistical considerations, together with the propensity for native cells to form teratomas, make it unlikely that embryonic or fetal stem cells will be practical. Fortunately, these issues do not pertain to the use of human amnion epithelial cells (hAECs), or umbilical cord blood (UCB) stem cells that are readily and economically obtained from the placenta and umbilical cord discarded at birth. These cells have the potential for transplantation to the newborn where brain injury is diagnosed or even suspected. We will explore the novel characteristics of hAECs and undifferentiated UCB cells, as well as UCB-derived endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs), and how immunomodulation and anti-inflammatory properties are principal mechanisms of action that are common to these cells, and which in turn may ameliorate the cerebral hypoxia and inflammation that are final pathways in the pathogenesis of perinatal brain

  10. Activation of the Canonical Bone Morphogenetic Protein (BMP) Pathway during Lung Morphogenesis and Adult Lung Tissue Repair

    PubMed Central

    Sountoulidis, Alexandros; Stavropoulos, Athanasios; Giaglis, Stavros; Apostolou, Eirini; Monteiro, Rui; Chuva de Sousa Lopes, Susana M.; Chen, Huaiyong; Stripp, Barry R.; Mummery, Christine; Andreakos, Evangelos; Sideras, Paschalis

    2012-01-01

    Signaling by Bone Morphogenetic Proteins (BMP) has been implicated in early lung development, adult lung homeostasis and tissue-injury repair. However, the precise mechanism of action and the spatio-temporal pattern of BMP-signaling during these processes remains inadequately described. To address this, we have utilized a transgenic line harboring a BMP-responsive eGFP-reporter allele (BRE-eGFP) to construct the first detailed spatiotemporal map of canonical BMP-pathway activation during lung development, homeostasis and adult-lung injury repair. We demonstrate that during the pseudoglandular stage, when branching morphogenesis progresses in the developing lung, canonical BMP-pathway is active mainly in the vascular network and the sub-epithelial smooth muscle layer of the proximal airways. Activation of the BMP-pathway becomes evident in epithelial compartments only after embryonic day (E) 14.5 primarily in cells negative for epithelial-lineage markers, located in the proximal portion of the airway-tree, clusters adjacent to neuro-epithelial-bodies (NEBs) and in a substantial portion of alveolar epithelial cells. The pathway becomes activated in isolated E12.5 mesenchyme-free distal epithelial buds cultured in Matrigel suggesting that absence of reporter activity in these regions stems from a dynamic cross-talk between endoderm and mesenchyme. Epithelial cells with activated BMP-pathway are enriched in progenitors capable of forming colonies in three-dimensional Matrigel cultures. As lung morphogenesis approaches completion, eGFP-expression declines and in adult lung its expression is barely detectable. However, upon tissue-injury, either with naphthalene or bleomycin, the canonical BMP-pathways is re-activated, in bronchial or alveolar epithelial cells respectively, in a manner reminiscent to early lung development and in tissue areas where reparatory progenitor cells reside. Our studies illustrate the dynamic activation of canonical BMP-pathway during lung

  11. Lung development and repair: Contribution of the ciliated lineage

    PubMed Central

    Rawlins, Emma L.; Ostrowski, Lawrence E.; Randell, Scott H.; Hogan, Brigid L. M.

    2007-01-01

    The identity of the endogenous epithelial cells in the adult lung that are responsible for normal turnover and repair after injury is still controversial. In part, this is due to a paucity of highly specific genetic lineage tools to follow efficiently the fate of the major epithelial cell populations: the basal, secretory, ciliated, neuroendocrine, and alveolar cells. As part of a program to address this problem we have used a 1-kb FOXJ1 promoter to drive CreER in the ciliated cells of the embryonic and adult lung. Analysis of FOXJ1-GFP transgenic lungs shows that labeled cells appear in a proximal-distal pattern during embryogenesis and that the promoter drives expression in all ciliated cells. Using FOXJ1CreER adult mice, we have followed the fate of ciliated cells after epithelial injury by naphthalene or sulfur dioxide. From quantitative analysis and confocal microscopy we conclude that ciliated cells transiently change their morphology in response to lung injury but do not proliferate or transdifferentiate as part of the repair process. PMID:17194755

  12. Secondary alveolar bone grafting: our experience with olecranon bone graft.

    PubMed

    Nadal, Emmanuela; Sabás, Mariana; Dogliotti, Pedro; Espósito, Raquel

    2010-03-01

    Management of alveolar cleft has dramatically changed during the last century: secondary alveolar bone grafting is now an integral part of cleft palate and craniofacial center's protocols. The objectives of alveolar repair and bone grafting are as follows: providing a continuous and stable maxillary dental arch, closure of oronasal fistulae, adequate bone for tooth eruption or orthodontic movement, and nasal base support, improving facial aesthetic. Although cancellous iliac bone is the donor site selected more frequently, bone grafts harvested from different sites have been advocated to decrease donor site morbidity.The aim of this study was to propose and evaluate the use of olecranon as a donor site in 24 patients with secondary alveolar cleft. The graft is taken as a single piece to fit the alveolar cleft defect, and it includes periosteum and corticocancellous bone to improve early vascularization and greater volume maintenance. PMID:20186086

  13. Loss of Hypoxia-Inducible Factor 2 Alpha in the Lung Alveolar Epithelium of Mice Leads to Enhanced Eosinophilic Inflammation in Cobalt-Induced Lung Injury

    PubMed Central

    Proper, Steven P.; Saini, Yogesh; LaPres, John J.

    2014-01-01

    Hard metal lung disease (HMLD) is an occupational lung disease specific to inhalation of cobalt-containing particles whose mechanism is largely unknown. Cobalt is a known hypoxia mimic and stabilizer of the alpha subunits of hypoxia-inducible factors (HIFs). Previous work revealed that though HIF1α contrib utes to cobalt toxicity in vitro, loss of HIF1α in the alveolar epithelial cells does not provide in vivo protection from cobalt-induced lung inflammation. HIF1α and HIF2α show unique tissue expression profiles, and HIF2α is known to be the predominant HIF mRNA isoform in the adult lung. Thus, if HIF2α activation by cobalt contributes to pathophysiology of HMLD, we hypothesized that loss of HIF2α in lung epithelium would provide protection from cobalt-induced inflammation. Mice with HIF2α-deficiency in Club and alveolar type II epithelial cells (ATIIs) (HIF2αΔ/Δ) were exposed to cobalt (60 µg/day) or saline using a subacute occupational exposure model. Bronchoalveolar lavage cellularity, cytokines, qRT-PCR, and histopathology were analyzed. Results show that loss of HIF2α leads to enhanced eosinophilic inflammation and increased goblet cell metaplasia. Additionally, control mice demonstrated a mild recovery from cobalt-induced lung injury compared with HIF2αΔ/Δ mice, suggesting a role for epithelial HIF2α in repair mechanisms. The expression of important cytokines, such as interleukin (IL)-5 and IL-10, displayed significant differences following cobalt exposure when HIF2αΔ/Δ and control mice were compared. In summary, our data suggest that although loss of HIF2α does not afford protection from cobalt-induced lung inflammation, epithelial HIF2α signaling does play an important role in modulating the inflammatory and repair response in the lung. PMID:24218148

  14. Loss of hypoxia-inducible factor 2 alpha in the lung alveolar epithelium of mice leads to enhanced eosinophilic inflammation in cobalt-induced lung injury.

    PubMed

    Proper, Steven P; Saini, Yogesh; Greenwood, Krista K; Bramble, Lori A; Downing, Nathaniel J; Harkema, Jack R; Lapres, John J

    2014-02-01

    Hard metal lung disease (HMLD) is an occupational lung disease specific to inhalation of cobalt-containing particles whose mechanism is largely unknown. Cobalt is a known hypoxia mimic and stabilizer of the alpha subunits of hypoxia-inducible factors (HIFs). Previous work revealed that though HIF1α contrib utes to cobalt toxicity in vitro, loss of HIF1α in the alveolar epithelial cells does not provide in vivo protection from cobalt-induced lung inflammation. HIF1α and HIF2α show unique tissue expression profiles, and HIF2α is known to be the predominant HIF mRNA isoform in the adult lung. Thus, if HIF2α activation by cobalt contributes to pathophysiology of HMLD, we hypothesized that loss of HIF2α in lung epithelium would provide protection from cobalt-induced inflammation. Mice with HIF2α-deficiency in Club and alveolar type II epithelial cells (ATIIs) (HIF2α(Δ/Δ)) were exposed to cobalt (60 µg/day) or saline using a subacute occupational exposure model. Bronchoalveolar lavage cellularity, cytokines, qRT-PCR, and histopathology were analyzed. Results show that loss of HIF2α leads to enhanced eosinophilic inflammation and increased goblet cell metaplasia. Additionally, control mice demonstrated a mild recovery from cobalt-induced lung injury compared with HIF2α(Δ/Δ) mice, suggesting a role for epithelial HIF2α in repair mechanisms. The expression of important cytokines, such as interleukin (IL)-5 and IL-10, displayed significant differences following cobalt exposure when HIF2α(Δ/Δ) and control mice were compared. In summary, our data suggest that although loss of HIF2α does not afford protection from cobalt-induced lung inflammation, epithelial HIF2α signaling does play an important role in modulating the inflammatory and repair response in the lung. PMID:24218148

  15. Pulmonary alveolar proteinosis.

    PubMed

    Borie, R; Danel, C; Debray, M-P; Taille, C; Dombret, M-C; Aubier, M; Epaud, R; Crestani, B

    2011-06-01

    Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disease characterised by alveolar accumulation of surfactant. It may result from mutations in surfactant proteins or granulocyte macrophage-colony stimulating factor (GM-CSF) receptor genes, it may be secondary to toxic inhalation or haematological disorders, or it may be auto-immune, with anti-GM-CSF antibodies blocking activation of alveolar macrophages. Auto-immune alveolar proteinosis is the most frequent form of PAP, representing 90% of cases. Although not specific, high-resolution computed tomography shows a characteristic "crazy paving" pattern. In most cases, bronchoalveolar lavage findings establish the diagnosis. Whole lung lavage is the most effective therapy, especially for auto-immune disease. Novel therapies targeting alveolar macrophages (recombinant GM-CSF therapy) or anti-GM-CSF antibodies (rituximab and plasmapheresis) are being investigated. Our knowledge of the pathophysiology of PAP has improved in the past 20 yrs, but therapy for PAP still needs improvement. PMID:21632797

  16. Depletion of resident alveolar macrophages does not prevent Fas-mediated lung injury in mice.

    PubMed

    Bem, R A; Farnand, A W; Wong, V; Koski, A; Rosenfeld, M E; van Rooijen, N; Frevert, C W; Martin, T R; Matute-Bello, G

    2008-08-01

    Activation of the Fas/Fas ligand (FasL) system in the lungs results in a form of injury characterized by alveolar epithelial apoptosis and neutrophilic inflammation. Studies in vitro show that Fas activation induces apoptosis in alveolar epithelial cells and cytokine production in alveolar macrophages. The main goal of this study was to determine the contribution of alveolar macrophages to Fas-induced lung inflammation in mice, by depleting alveolar macrophages using clodronate-containing liposomes. Liposomes containing clodronate or PBS were instilled by intratracheal instillation. After 24 h, the mice received intratracheal instillations of the Fas-activating monoclonal antibody Jo2 or an isotype control antibody and were studied 18 h later. The Jo2 MAb induced increases in bronchoalveolar lavage fluid (BALF) total neutrophils, lung caspase-3 activity, and BALF total protein and worsened histological lung injury in the macrophage-depleted mice. Studies in vitro showed that Fas activation induced the release of the cytokine KC in a mouse lung epithelial cell line, MLE-12. These results suggest that the lung inflammatory response to Fas activation is not primarily dependent on resident alveolar macrophages and may instead depend on cytokine release by alveolar epithelial cells. PMID:18556802

  17. [Pulmonary alveolar proteinosis].

    PubMed

    Floarea-Strat, Alina; Stanciu, Adriana; Creţeanu, Mihai

    2003-01-01

    It is a disease of obscure cause that is characterized by the accumulation of a granular material that contains abundant lipid within the alveoli of lung. Pulmonary alveolar proteinosis (PAP) has been divided into a congenital and an adult form. The acquired form has been subdivided into a idiopathic form and a secondary form associated with a know disorder or exposure as silica, aluminium, titanium. Dyspnea and cough are the most common presenting symptoms. Chest pain, hemoptysis, fever and weight loss are variably reported. Pathogenesis remains unknown, but evidence points to a dysfunction of alveolar macrophages. Mice genetically deficient in granulocyte macrophagecolony stimulating factor (GM-CSF) show an alveolar proteinosis. A neutralizing antibody against GM-CSF was found in bronchoalveolar lavage fluid and serum of patients with idiopathic PAP. Currently, no specific therapy exists for pulmonary alveolar proteinosis, and sequential whole lung lavage is standard treatment. PMID:14756054

  18. γδ T Cells Are Necessary for Platelet and Neutrophil Accumulation in Limbal Vessels and Efficient Epithelial Repair after Corneal Abrasion

    PubMed Central

    Li, Zhijie; Burns, Alan R.; Rumbaut, Rolando E.; Smith, C. Wayne

    2007-01-01

    Corneal epithelial abrasion in C57BL/6 mice induces an inflammatory response with peak accumulation of neutrophils in the corneal stroma within 12 hours. Platelets localize in the limbal vessels throughout the same time course as neutrophils and contribute to wound healing because antibody-dependent depletion of platelets retards epithelial division and wound closure. In the present study, T cells in the limbal epithelium were found to predominantly express the γδ T-cell receptor (TCR). Corneal abrasion in wild-type, CD11a−/−, and P-sel−/− mice increased the numbers of γδ T cells in the limbal and peripheral corneal epithelium and in the corneal stroma adjacent to the limbal blood vessels. Intercellular adhesion molecule (ICAM)-1−/− mice exhibited a reduction in γδ T-cell accumulation. TCRδ−/− mice exhibited reduced inflammation and delayed epithelial wound healing as evidenced by delayed wound closure, reduced epithelial cell division, reduced neutrophil infiltration, and reduced epithelial cell density at 96 hours after wounding. TCRδ−/− mice also exhibited >60% reduction in platelet localization in the limbus despite similar platelet counts and platelet function assessed with an in vivo thrombosis model. These results are consistent with the conclusion that γδ T cells are necessary for efficient inflammation, platelet localization in the limbus, and epithelial wound healing after corneal abrasion. PMID:17675580

  19. [Pulmonary alveolar proteinosis].

    PubMed

    Hutyrová, B

    2007-10-01

    Pulmonary alveolar proteinosis is a rare disease characterised by excessive accumulation of surfactant components in the alveoli and the distal airways with minimum inflammatory reaction and fibrosis of pulmonary interstitium. Three clinical forms of pulmonary alveolar proteinosis are distinguished - congenital, primary and secondary. Results of ultrastructural, biochemical and functional analyses and studies performed on genetically modified mice support the presumption that accumulation of surfactant in pulmonary alveolar proteinosis is a result of a degradation disorder and of diminished clearance of the surfactant from the alveolar space rather than of excessive synthesis of surfactant components. Over the last 15 years, significant discoveries have been made which have helped to clarify the etiology and pathogenesis of the disease. A number of gene mutations have been discovered which lead to the development of congenital pulmonary proteinosis. Apart from impaired surfactant protein function, a key role in the development of pulmonary alveolar proteinosis is played by the signal pathway of granulocyte and macrophage colonies stimulating growth factor (GM-CSF) which is necessary for the functioning of alveolar macrophages and for surfactant homeostasis. The role of GM-CSF has been proven especially in primary pulmonary alveolar proteinosis which is currently considered an auto-immune disease involving the development of GM-CSF neutralising autoantibodies. In most cases, the prognosis for the disease in adult patients is good, even though there is a 10 to 15% rate of patients who develop respiratory failure. Total pulmonary lavage is considered to be the standard method of treatment. In recent years, recombinant human GM-CSF has been studied as a prospective therapy for the treatment of pulmonary alveolar proteinosis. PMID:18072433

  20. Further examination of alveolar septal adaptation to left pneumonectomy in the adult lung.

    PubMed

    Hsia, Connie C W; Johnson, Robert L

    2006-04-28

    Recent data from our laboratory are presented concerning alveolar septal adaptation following 42-45% lung resection by left pneumonectomy (PNX) in adult foxhounds compared to sham-operated control animals. Results confirm our previous conclusion that compensation in the remaining lung occurs without a net growth of additional alveolar septal tissue. The major ultrastructural responses are (a) alveolar capillary distention, which recruits capillary blood volume and surface area, leading to a 30-50% increase in lung diffusing capacity estimated by morphometry, a magnitude similar to that measured by physiologic methods; (b) a selectively increased volume of type 2 alveolar epithelial cells. These data, taken together with the balanced compensatory growth of alveolar septal cells observed in adult dogs following 55-58% lung resection by right PNX, support a graded alveolar cellular response to chronic mechanical strain with the alveolar epithelial cells being activated first; as strain increases further with greater lung resection other alveolar cells also become activated leading to an overt increase in septal tissue volume. The spatial distribution of lobar mechanical strain and lobar tissue volume assessed by high resolution computed tomography was markedly non-uniform after PNX, suggesting possible non-uniform distribution of alveolar cellular response. The sequential activation of physiologic recruitment and cellular adaptation confer additive functional benefits that optimize long-term exercise performance after PNX. PMID:16563882

  1. Correlation of Organic Cation/Carnitine Transporter 1 and Multidrug Resistance-Associated Protein 1 Transport Activities With Protein Expression Levels in Primary Cultured Human Tracheal, Bronchial, and Alveolar Epithelial Cells.

    PubMed

    Sakamoto, Atsushi; Suzuki, Shinobu; Matsumaru, Takehisa; Yamamura, Norio; Uchida, Yasuo; Tachikawa, Masanori; Terasaki, Tetsuya

    2016-02-01

    Understanding how transporters contribute to the distribution of inhaled drugs in the lung is important for the discovery and development of such drugs. Protein expression levels may be useful to predict and understand drug distribution. As previously reported, organic cation/carnitine transporter 1 (OCTN1) and multidrug resistance-associated protein 1 (MRP1) have higher levels of protein expression among transporters in primary cultured human lung cells. Nevertheless, it is unclear to what extent transport activity correlates with transporter protein expression. The purpose is to evaluate whether differences in OCTN1 and MRP1 protein expression govern the respective transport activity in primary cultured human lung cells. The model substrates of 4-[4-(dimethylamino) styryl]-N-methylpyridinium iodide (ASP(+)) and carboxy-dichlorofluorescein (CDF) for OCTN1 and MRP1, respectively, were used in the lung cells from five donors. Significant correlation was found between the kinetic parameter Vmax for ASP(+) and OCTN1 protein expression in plasma membrane of tracheal, bronchial, and alveolar cells (r(2) = 0.965, 0.834, and 0.877, respectively), and between the efflux of CDF and MRP1 protein expression in plasma membrane of tracheal, bronchial, and alveolar cells (r(2) = 0.800, 0.904, and 0.790, respectively). These findings suggest that OCTN1 and MRP1 protein concentrations are determinants for drug distribution in the lung. PMID:26429295

  2. Macrophage-epithelial interactions in pulmonary alveoli.

    PubMed

    Bhattacharya, Jahar; Westphalen, Kristin

    2016-07-01

    Alveolar macrophages have been investigated for years by approaches involving macrophage extraction from the lung by bronchoalveolar lavage, or by cell removal from lung tissue. Since extracted macrophages are studied outside their natural milieu, there is little understanding of the extent to which alveolar macrophages interact with the epithelium, or with one another to generate the lung's innate immune response to pathogen challenge. Here, we review new evidence of macrophage-epithelial interactions in the lung, and we address the emerging understanding that the alveolar epithelium plays an important role in orchestrating the macrophage-driven immune response. PMID:27170185

  3. Gene Expression of Rat Alveolar Type II Cells during Hyperoxia Exposure and Early Recovery

    PubMed Central

    Chen, Zhongming; Chintagari, Narendranath Reddy; Guo, Yujie; Bhaskaran, Manoj; Chen, Jiwang; Gao, Li; Jin, Nili; Weng, Tingting; Liu, Lin

    2007-01-01

    Alveolar epithelial cell (AEC) injury and repair during hyperoxia exposure and recovery have been investigated for decades, but the molecular mechanisms of these processes are not clear. To identify potentially important genes involved in lung injury and repair, we studied the gene expression profiles of isolated AEC II from control, 48-hour hyperoxia-exposed (>95% O2) and 1-7 day recovering rats using a DNA microarray containing 10,000 genes. Fifty genes showed significant differential expression between two or more time points (p<0.05, fold change >2). These genes can be classified into 8 unique gene expression patterns. Real-time PCR verified 14 selected genes in three patterns related to hyperoxia exposure and early recovery. The change in the protein level for two of the selected genes, bmp-4 and retnla, paralleled that of the mRNA level. Many of these genes were found to be involved in cell proliferation and differentiation. In an in vitro AEC trans-differentiation culture model using AEC II isolated from control and 48 hrs hyperoxia-exposed rats, the expression of the cell proliferation and differentiation genes identified above were consistent with their predicted roles in the trans-differentiation of AEC. These data indicate that a coordinated mechanism may control AEC differentiation during in vivo hyperoxia exposure and recovery as well as during in vitro AEC culture. PMID:17640573

  4. Pulmonary alveolar proteinosis.

    PubMed

    Khan, Ajmal; Agarwal, Ritesh

    2011-07-01

    Pulmonary alveolar proteinosis is a rare but potentially treatable disease, characterized by impaired surfactant metabolism that leads to accumulation in the alveoli of proteinaceous material rich in surfactant protein and its component. Novel insights from an animal model aided the discovery of granulocyte macrophage colony stimulating factor (GM-CSF) antibodies as a pathogenetic mechanism in human pulmonary alveolar proteinosis. The vast majority of pulmonary alveolar proteinosis occurs as an autoimmune disease; less commonly, it is congenital or secondary to an underlying disorder such as infection, hematological malignancy, or immunodeficiency. The subacute indolent course of this disease often delays the diagnosis by months to years. Crazy-paving appearance in a geographic distribution is a characteristic feature of this disease visible on high-resolution computed tomography (CT). A definitive diagnosis, however, requires lung biopsy, which typically shows partial or complete filling of alveoli with periodic-acid-Schiff-positive granular and eosinophilic material in preserved alveolar architecture. Patients with minimal symptoms are managed conservatively, whereas patients with hypoxemia require a more aggressive approach. Whole-lung lavage is the most widely accepted therapy for symptomatic pulmonary alveolar proteinosis. Correction of GM-CSF deficiency with exogenous GM-CSF is an alternative therapy. The combination of a systemic treatment (GM-CSF) and a local treatment (whole-lung lavage) augmenting the action of one another is a promising new approach. As the knowledge about this rare disease increases, the role of novel therapies is likely to be better defined and optimized. PMID:21496372

  5. Pulmonary alveolar proteinosis.

    PubMed

    Patel, Sandeep M; Sekiguchi, Hiroshi; Reynolds, Jordan P; Krowka, Michael J

    2012-01-01

    Pulmonary alveolar proteinosis (PAP) is a disease of alveolar accumulation of phospholipoproteinaceous material that results in gas exchange impairment leading to dyspnea and alveolar infiltrates. There are three forms of PAP: congenital, acquired and idiopathic; of which the latter two are predominant in the adult population. Previous case studies have found that the acquired form can be secondary to various autoimmune, infectious, malignant and environmental etiologies. Recent advances in the understanding of the pathophysiology of PAP demonstrate that the idiopathic form is due to antigranulocyte macrophage-colony stimulating factor antibodies. Therapeutic targets that replace granulocyte macrophage colony stimulating factor or remove these antibodies are being actively developed. The current standard of care is to perform whole lung lavage on these patients to clear the alveolar space to help improve respiratory physiology. A case of PAP is reported, followed by a literature review on the diagnosis and management of this rare condition with the aim of increasing awareness among physicians when treating patients who present with alveolar infiltrates. PMID:22891182

  6. An estimation of mechanical stress on alveolar walls during repetitive alveolar reopening and closure.

    PubMed

    Chen, Zheng-Long; Song, Yuan-Lin; Hu, Zhao-Yan; Zhang, Su; Chen, Ya-Zhu

    2015-08-01

    Alveolar overdistension and mechanical stresses generated by repetitive opening and closing of small airways and alveoli have been widely recognized as two primary mechanistic factors that may contribute to the development of ventilator-induced lung injury. A long-duration exposure of alveolar epithelial cells to even small, shear stresses could lead to the changes in cytoskeleton and the production of inflammatory mediators. In this paper, we have made an attempt to estimate in situ the magnitudes of mechanical stresses exerted on the alveolar walls during repetitive alveolar reopening by using a tape-peeling model of McEwan and Taylor (35). To this end, we first speculate the possible ranges of capillary number (Ca) ≡ μU/γ (a dimensionless combination of surface tension γ, fluid viscosity μ, and alveolar opening velocity U) during in vivo alveolar opening. Subsequent calculations show that increasing respiratory rate or inflation rate serves to increase the values of mechanical stresses. For a normal lung, the predicted maximum shear stresses are <15 dyn/cm(2) at all respiratory rates, whereas for a lung with elevated surface tension or viscosity, the maximum shear stress will notably increase, even at a slow respiratory rate. Similarly, the increased pressure gradients in the case of elevated surface or viscosity may lead to a pressure drop >300 dyn/cm(2) across a cell, possibly inducing epithelial hydraulic cracks. In addition, we have conceived of a geometrical model of alveolar opening to make a prediction of the positive end-expiratory pressure (PEEP) required to splint open a collapsed alveolus, which as shown by our results, covers a wide range of pressures, from several centimeters to dozens of centimeters of water, strongly depending on the underlying pulmonary conditions. The establishment of adequate regional ventilation-to-perfusion ratios may prevent recruited alveoli from reabsorption atelectasis and accordingly, reduce the required levels of

  7. Gamma delta T Cells Are Necessary for Platelet and Neutrophil Accumulation in Limbal Vessels and Efficient Epithelial Repair after Corneal Abrasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corneal epithelial abrasion in C57BL/6 mice induces an inflammatory response, with peak accumulation of neutrophils in the corneal stroma within 12 hours. Platelets localize in the limbal vessels throughout the same time course as neutrophils and contribute to wound healing because antibody-dependen...

  8. Pulmonary alveolar microlithiasis

    PubMed Central

    Kashyap, Surender; Mohapatra, Prasanta R.

    2013-01-01

    Pulmonary alveolar microlithiasis (PAM) is a rare, chronic lung disease with bilateral intra-alveolar calcium and phosphate deposition throughout the lung parenchyma with predominance to lower and midzone. Although, etiology and pathogenesis of PAM is not fully understood, the mutation in SLC34A2 gene that encodes a sodium-phosphate co-transporter in alveolar type II cells resulting in the accumulation and forming of microliths rich in calcium phosphate (due to impaired clearance) are considered to be the cause of the disease. Chest radiograph and high-resolution CT of thorax are nearly pathognomonic for diagnosing PAM. HRCT demonstrates diffuse micronodules showing slight perilobular predominance resulting in calcification of interlobular septa. Patients with PAM are asymptomatic till development of hypoxemia and cor-pulmonale. No therapy has been proven to be beneficial except lung transplantation. PMID:23741096

  9. Critical determinants of uptake and translocation of nanoparticles by the human pulmonary alveolar epithelium.

    PubMed

    Thorley, Andrew J; Ruenraroengsak, Pakatip; Potter, Thomas E; Tetley, Teresa D

    2014-11-25

    The ability to manipulate the size and surface properties of nanomaterials makes them a promising vector for improving drug delivery and efficacy. Inhalation is a desirable route of administration as nanomaterials preferentially deposit in the alveolar region, a large surface area for drug absorption. However, as yet, the mechanisms by which particles translocate across the alveolar epithelial layer are poorly understood. Here we show that human alveolar type I epithelial cells internalize nanoparticles, whereas alveolar type II epithelial cells do not, and that nanoparticles translocate across the epithelial monolayer but are unable to penetrate the tight junctions between cells, ruling out paracellular translocation. Furthermore, using siRNA, we demonstrate that 50 nm nanoparticles enter largely by passive diffusion and are found in the cytoplasm, whereas 100 nm nanoparticles enter primarily via clathrin- and also caveolin-mediated endocytosis and are found in endosomes. Functionalization of nanoparticles increases their uptake and enhances binding of surfactant which further promotes uptake. Thus, we demonstrate that uptake and translocation across the pulmonary epithelium is controlled by alveolar type I epithelial cells, and furthermore, we highlight a number of factors that should be considered when designing new nanomedicines in order to improve drug delivery to the lung. PMID:25360809

  10. Critical Determinants of Uptake and Translocation of Nanoparticles by the Human Pulmonary Alveolar Epithelium

    PubMed Central

    2015-01-01

    The ability to manipulate the size and surface properties of nanomaterials makes them a promising vector for improving drug delivery and efficacy. Inhalation is a desirable route of administration as nanomaterials preferentially deposit in the alveolar region, a large surface area for drug absorption. However, as yet, the mechanisms by which particles translocate across the alveolar epithelial layer are poorly understood. Here we show that human alveolar type I epithelial cells internalize nanoparticles, whereas alveolar type II epithelial cells do not, and that nanoparticles translocate across the epithelial monolayer but are unable to penetrate the tight junctions between cells, ruling out paracellular translocation. Furthermore, using siRNA, we demonstrate that 50 nm nanoparticles enter largely by passive diffusion and are found in the cytoplasm, whereas 100 nm nanoparticles enter primarily via clathrin- and also caveolin-mediated endocytosis and are found in endosomes. Functionalization of nanoparticles increases their uptake and enhances binding of surfactant which further promotes uptake. Thus, we demonstrate that uptake and translocation across the pulmonary epithelium is controlled by alveolar type I epithelial cells, and furthermore, we highlight a number of factors that should be considered when designing new nanomedicines in order to improve drug delivery to the lung. PMID:25360809

  11. Alveolar surfactant homeostasis and the pathogenesis of pulmonary disease.

    PubMed

    Whitsett, Jeffrey A; Wert, Susan E; Weaver, Timothy E

    2010-01-01

    The alveolar region of the lung creates an extensive epithelial surface that mediates the transfer of oxygen and carbon dioxide required for respiration after birth. Maintenance of pulmonary function depends on the function of type II epithelial cells that synthesize and secrete pulmonary surfactant lipids and proteins, reducing the collapsing forces created at the air-liquid interface in the alveoli. Genetic and acquired disorders associated with the surfactant system cause both acute and chronic lung disease. Mutations in the ABCA3, SFTPA, SFTPB, SFTPC, SCL34A2, and TERT genes disrupt type II cell function and/or surfactant homeostasis, causing neonatal respiratory failure and chronic interstitial lung disease. Defects in GM-CSF receptor function disrupt surfactant clearance, causing pulmonary alveolar proteinosis. Abnormalities in the surfactant system and disruption of type II cell homeostasis underlie the pathogenesis of pulmonary disorders previously considered idiopathic, providing the basis for improved diagnosis and therapies of these rare lung diseases. PMID:19824815

  12. Alveolar Surfactant Homeostasis and the Pathogenesis of Pulmonary Disease

    PubMed Central

    Whitsett, Jeffrey A.; Wert, Susan E.; Weaver, Timothy E.

    2014-01-01

    The alveolar region of the lung creates an extensive epithelial surface that mediates the transfer of oxygen and carbon dioxide required for respiration after birth. Maintenance of pulmonary function depends on the function of type II epithelial cells that synthesize and secrete pulmonary surfactant lipids and proteins, reducing the collapsing forces created at the air-liquid interface in the alveoli. Genetic and acquired disorders associated with the surfactant system cause both acute and chronic lung disease. Mutations in the ABCA3, SFTPA, SFTPB, SFTPC, SCL34A2, and TERT genes disrupt type II cell function and/or surfactant homeostasis, causing neonatal respiratory failure and chronic interstitial lung disease. Defects in GM-CSF receptor function disrupt surfactant clearance, causing pulmonary alveolar proteinosis. Abnormalities in the surfactant system and disruption of type II cell homeostasis underlie the pathogenesis of pulmonary disorders previously considered idiopathic, providing the basis for improved diagnosis and therapies of these rare lung diseases. PMID:19824815

  13. Permanent alveolar collapse is the predominant mechanism in idiopathic pulmonary fibrosis.

    PubMed

    Todd, Nevins W; Atamas, Sergei P; Luzina, Irina G; Galvin, Jeffrey R

    2015-08-01

    Alveolar epithelial cell loss and impaired epithelial cell regeneration are currently accepted as central initiating events in idiopathic pulmonary fibrosis (IPF), but subsequent downstream effects remain uncertain. The most accepted downstream effect is aberrant and dysregulated mesenchymal cell proliferation and excess extracellular matrix (ECM) accumulation. However, biochemical and imaging studies have perhaps somewhat surprisingly indicated little increase in total lung collagen and lung tissue, and have rather shown a substantial decrease in lung aeration and lung air volume. Loss of tissue aeration is a consequence of alveolar collapse, which occurs in IPF as a result of apposition and septal incorporation of denuded basal lamina. Permanent alveolar collapse is well-documented following epithelial injury, has the ability to mimic interstitial fibrosis radiologically and histologically, and is a better supported explanation than dysregulated fibroblast proliferation and excess ECM accumulation for the constellation of findings in patients with IPF. PMID:26165208

  14. The Role of Angiotensin II and Cyclic AMP in Alveolar Active Sodium Transport

    PubMed Central

    Ismael-Badarneh, Reem; Guetta, Julia; Klorin, Geula; Berger, Gidon; Abu-saleh, Niroz; Abassi, Zaid; Azzam, Zaher S.

    2015-01-01

    Active alveolar fluid clearance is important in keeping airspaces free of edema. Angiotensin II plays a role in the pathogenesis of hypertension, heart failure and others. However, little is known about its contribution to alveolar fluid clearance. Angiotensin II effects are mediated by two specific receptors; AT1 and AT2. The localization of these two receptors in the lung, specifically in alveolar epithelial cells type II, was recently reported. We hypothesize that Angiotensin II may have a role in the regulation of alveolar fluid clearance. We investigated the effect of Angiotensin II on alveolar fluid clearance in rats using the isolated perfused lung model and isolated rat alveolar epithelial cells. The rate of alveolar fluid clearance in control rats was 8.6% ± 0.1 clearance of the initial volume and decreased by 22.5%, 28.6%, 41.6%, 48.7% and 39% in rats treated with 10-10 M, 10-9 M, 10-8 M, 10-7 M or 10-6 M of Ang II respectively (P < 0.003). The inhibitory effect of Angiotensin II was restored in losartan, an AT1 specific antagonist, pretreated rats, indicating an AT1 mediated effect of Ang II on alveolar fluid clearance. The expression of Na,K-ATPase proteins and cAMP levels in alveolar epithelial cells were down-regulated following the administration of Angiotensin II; suggesting that cAMP may be involved in AngII-induced reduced Na,K-ATPase expression, though the contribution of additional factors could not be excluded. We herein suggest a novel mechanism of clinical relevance by which angiotensin adversely impairs the ability of the lungs to clear edema. PMID:26230832

  15. Increased alveolar soluble annexin V promotes lung inflammation and fibrosis.

    PubMed

    Buckley, Susan; Shi, Wei; Xu, Wei; Frey, Mark R; Moats, Rex; Pardo, Annie; Selman, Moises; Warburton, David

    2015-11-01

    The causes underlying the self-perpetuating nature of idiopathic pulmonary fibrosis (IPF), a progressive and usually lethal disease, remain unknown. We hypothesised that alveolar soluble annexin V contributes to lung fibrosis, based on the observation that human IPF bronchoalveolar lavage fluid (BALF) containing high annexin V levels promoted fibroblast involvement in alveolar epithelial wound healing that was reduced when annexin V was depleted from the BALF. Conditioned medium from annexin V-treated alveolar epithelial type 2 cells (AEC2), but not annexin V per se, induced proliferation of human fibroblasts and contained pro-fibrotic, IPF-associated proteins, as well as pro-inflammatory cytokines that were found to correlate tightly (r>0.95) with annexin V levels in human BALF. ErbB2 receptor tyrosine kinase in AECs was activated by annexin V, and blockade reduced the fibrotic potential of annexin V-treated AEC-conditioned medium. In vivo, aerosol delivery of annexin V to mouse lung induced inflammation, fibrosis and increased hydroxyproline, with activation of Wnt, transforming growth factor-β, mitogen-activated protein kinase and nuclear factor-κB signalling pathways, as seen in IPF. Chronically increased alveolar annexin V levels, as reflected in increased IPF BALF levels, may contribute to the progression of IPF by inducing the release of pro-fibrotic mediators. PMID:26160872

  16. The H2S-generating enzymes cystathionine β-synthase and cystathionine γ-lyase play a role in vascular development during normal lung alveolarization.

    PubMed

    Madurga, Alicia; Golec, Anita; Pozarska, Agnieszka; Ishii, Isao; Mižíková, Ivana; Nardiello, Claudio; Vadász, István; Herold, Susanne; Mayer, Konstantin; Reichenberger, Frank; Fehrenbach, Heinz; Seeger, Werner; Morty, Rory E

    2015-10-01

    The gasotransmitter hydrogen sulfide (H2S) is emerging as a mediator of lung physiology and disease. Recent studies revealed that H2S administration limited perturbations to lung structure in experimental animal models of bronchopulmonary dysplasia (BPD), partially restoring alveolarization, limiting pulmonary hypertension, limiting inflammation, and promoting epithelial repair. No studies have addressed roles for endogenous H2S in lung development. H2S is endogenously generated by cystathionine β-synthase (Cbs) and cystathionine γ-lyase (Cth). We demonstrate here that the expression of Cbs and Cth in mouse lungs is dynamically regulated during lung alveolarization and that alveolarization is blunted in Cbs(-/-) and Cth(-/-) mouse pups, where a 50% reduction in the total number of alveoli was observed, without any impact on septal thickness. Laser-capture microdissection and immunofluorescence staining indicated that Cbs and Cth were expressed in the airway epithelium and lung vessels. Loss of Cbs and Cth led to a 100-500% increase in the muscularization of small- and medium-sized lung vessels, which was accompanied by increased vessel wall thickness, and an apparent decrease in lung vascular supply. Ablation of Cbs expression using small interfering RNA or pharmacological inhibition of Cth using propargylglycine in lung endothelial cells limited angiogenic capacity, causing a 30-40% decrease in tube length and a 50% decrease in number of tubes formed. In contrast, exogenous administration of H2S with GYY4137 promoted endothelial tube formation. These data confirm a key role for the H2S-generating enzymes Cbs and Cth in pulmonary vascular development and homeostasis and in lung alveolarization. PMID:26232299

  17. Combination of fluid and solid mechanical stresses contribute to cell death and detachment in a microfluidic alveolar model.

    PubMed

    Douville, Nicholas J; Zamankhan, Parsa; Tung, Yi-Chung; Li, Ran; Vaughan, Benjamin L; Tai, Cheng-Feng; White, Joshua; Christensen, Paul J; Grotberg, James B; Takayama, Shuichi

    2011-02-21

    Studies using this micro-system demonstrated significant morphological differences between alveolar epithelial cells (transformed human alveolar epithelial cell line, A549 and primary murine alveolar epithelial cells, AECs) exposed to combination of solid mechanical and surface-tension stresses (cyclic propagation of air-liquid interface and wall stretch) compared to cell populations exposed solely to cyclic stretch. We have also measured significant differences in both cell death and cell detachment rates in cell monolayers experiencing combination of stresses. This research describes new tools for studying the combined effects of fluid mechanical and solid mechanical stress on alveolar cells. It also highlights the role that surface tension forces may play in the development of clinical pathology, especially under conditions of surfactant dysfunction. The results support the need for further research and improved understanding on techniques to reduce and eliminate fluid stresses in clinical settings. PMID:21152526

  18. Rare combination of congenital heart disease and pulmonary alveolar proteinosis.

    PubMed

    Tanaka, Yuki; Miyamoto, Takashi; Yoshitake, Shuichi; Naito, Yuji; Kobayashi, Tomio

    2015-10-01

    Here, we describe a case of total anomalous pulmonary venous return with coarctation of the aorta that was diagnosed as pulmonary alveolar proteinosis at autopsy in a male infant. Surgical repair was performed at 1 day of age, but the infant died on postoperative day 51 due to respiratory insufficiency without any evidence of pulmonary venous obstruction. He had been unexpectedly diagnosed with pulmonary alveolar proteinosis and pulmonary hypoplasia on autopsy. Congenital pulmonary alveolar proteinosis is a serious condition with a high mortality rate, which should be considered in the differential diagnosis in patients with a clinical picture of pulmonary venous obstruction, because most patients are unable to survive without proper treatment. In this report, we address specific issues that should be discussed in such cases based on our recent experience. PMID:26310609

  19. Pulmonary alveolar proteinosis.

    PubMed

    Wang, Tisha; Lazar, Catherine A; Fishbein, Michael C; Lynch, Joseph P

    2012-10-01

    Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by the accumulation of surfactant lipids and protein in the alveolar spaces, with resultant impairment in gas exchange. The clinical course can be variable, ranging from spontaneous resolution to respiratory failure and death. PAP in all forms is caused by excessive accumulation of surfactant within the alveolar spaces. Autoimmune PAP accounts for the vast majority of cases in humans and is caused by autoantibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF), which results in impaired catabolism and clearance of surfactant lipids and proteins. Inherited or congenital forms of PAP are exceptionally rare and caused by mutations of genes encoding for surfactant proteins. Secondary forms of PAP are associated with diverse clinical disorders and are caused by reduced alveolar macrophage numbers or function with resultant reduced pulmonary clearance of surfactant. PAP is characterized by progressive exertional dyspnea and nonproductive cough with hypoxemia. Bilateral infiltrates are typically present on chest radiograph, and high-resolution computed tomography reveals diffuse ground-glass opacities and airspace consolidation with interlobular septal thickening in a characteristic "crazy paving" pattern. Although surgical lung biopsy will provide a definitive diagnosis, a combination of typical clinical and imaging features with periodic acid-Schiff (PAS)-positive material on bronchoalveolar lavage and transbronchial biopsies is usually sufficient. The standard of care for treatment of PAP remains whole lung lavage, but treatment is not required in all patients. Autoimmune PAP has also been successfully treated with GM-CSF, both inhaled and systemic, but the optimal dose, duration, and route of administration of GM-CSF have not been elucidated. PMID:23001804

  20. Expression of human carcinoembryonic antigen-related cell adhesion molecule 6 and alveolar progenitor cells in normal and injured lungs of transgenic mice.

    PubMed

    Lin, Shin-E; Barrette, Anne Marie; Chapin, Cheryl; Gonzales, Linda W; Gonzalez, Robert F; Dobbs, Leland G; Ballard, Philip L

    2015-12-01

    Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is expressed in the epithelium of various primate tissues, including lung airway and alveoli. In human lung, CEACAM6 is developmentally and hormonally regulated, protects surfactant function, has anti-apoptotic activity and is dysregulated in cancers. We hypothesized that alveolar CEACAM6 expression increases in lung injury and promotes cell proliferation during repair. Studies were performed in CEABAC transgenic mice-containing human CEACAM genes. The level of CEACAM6 in adult CEABAC lung was comparable to that in human infants; expression occurred in epithelium of airways and of some alveoli but rarely co-localized with markers of type I or type II cells. Ten days after bleomycin instillation, both the number of CEACAM6(+) cells and immunostaining intensity were elevated in injured lung areas, and there was increased co-localization with type I and II cell markers. To specifically address type II cells, we crossed CEABAC mice with animals expressing EGFP driven by the SP-C promoter. After bleomycin injury, partially flattened, elongated epithelial cells were observed that expressed type I cell markers and were primarily either EGFP(+) or CEACAM6(+). In cell cycle studies, mitosis was greater in CEACAM6(+) non-type II cells versus CEACAM6(+)/EGFP(+) cells. CEACAM6 epithelial expression was also increased after hyperoxic exposure and LPS instillation, suggesting a generalized response to acute lung injuries. We conclude that CEACAM6 expression is comparable in human lung and the CEABAC mouse. CEACAM6 in this model appears to be a marker of a progenitor cell population that contributes to alveolar epithelial cell replenishment after lung injury. PMID:26702074

  1. Meningocele repair

    MedlinePlus

    ... dysraphism repair; Meningomyelocele repair; Neural tube defect repair; Spina bifida repair ... a medical team with experience in children with spina bifida. Your baby will likely have an MRI (magnetic ...

  2. Is alveolar cleft reconstruction still controversial? (Review of literature)

    PubMed Central

    Seifeldin, Sameh A.

    2015-01-01

    Cleft lip and palate (CL/P) is a frequent congenital malformation that manifests in several varieties including unilateral or bilateral and complete or incomplete. Alveolar cleft reconstruction remains controversial with regard to timing, graft materials, surgical techniques, and methods of evaluation. Many studies have been conducted addressing these points to develop an acceptable universal protocol for managing CL/P. The primary goal of alveolar cleft reconstruction in CL/P patients is to provide a bony bridge at the cleft site that allows maxillary arch continuity, oronasal fistula repair, eruption of the permanent dentition into the newly formed bone, enhances nasal symmetry through providing alar base support, orthodontic movement and placement of osseointegrated implants when indicated. Other goals include improving speech, improvement of periodontal conditions, establishing better oral hygiene, and limiting growth disturbances. In order to rehabilitate oral function in CL/P patients alveolar bone grafting is necessary. Secondary bone grafting is the most widely accepted method for treating alveolar clefts. Autogenous bone graft is the primary source for reconstructing alveolar cleft defects and is currently the preferred grafting material. PMID:26792963

  3. Megalin mediates transepithelial albumin clearance from the alveolar space of intact rabbit lungs

    PubMed Central

    Buchäckert, Yasmin; Rummel, Sebastian; Vohwinkel, Christine U; Gabrielli, Nieves M; Grzesik, Benno A; Mayer, Konstantin; Herold, Susanne; Morty, Rory E; Seeger, Werner; Vadász, István

    2012-01-01

    The alveolo-capillary barrier is effectively impermeable to large solutes such as proteins. A hallmark of acute lung injury/acute respiratory distress syndrome is the accumulation of protein-rich oedema fluid in the distal airspaces. Excess protein must be cleared from the alveolar space for recovery; however, the mechanisms of protein clearance remain incompletely understood. In intact rabbit lungs 29.8 ± 2.2% of the radio-labelled alveolar albumin was transported to the vascular compartment at 37°C within 120 min, as assessed by real-time measurement of 125I-albumin clearance from the alveolar space. At 4°C or 22°C significantly lower albumin clearance (3.7 ± 0.4 or 16.2 ± 1.1%, respectively) was observed. Deposition of a 1000-fold molar excess of unlabelled albumin into the alveolar space or inhibition of cytoskeletal rearrangement or clathrin-dependent endocytosis largely inhibited the transport of 125I-albumin to the vasculature, while administration of unlabelled albumin to the vascular space had no effect on albumin clearance. Furthermore, albumin uptake capacity was measured as about 0.37 mg ml−1 in cultured rat lung epithelial monolayers, further highlighting the (patho)physiological relevance of active alveolar epithelial protein transport. Moreover, gene silencing and pharmacological inhibition of the multi-ligand receptor megalin resulted in significantly decreased albumin binding and uptake in monolayers of primary alveolar type II and type I-like and cultured lung epithelial cells. Our data indicate that clearance of albumin from the distal air spaces is facilitated by an active, high-capacity, megalin-mediated transport process across the alveolar epithelium. Further understanding of this mechanism is of clinical importance, since an inability to clear excess protein from the alveolar space is associated with poor outcome in patients with acute lung injury/acute respiratory distress syndrome. PMID:22826129

  4. Pulmonary alveolar proteinosis.

    PubMed

    Ioachimescu, O C; Kavuru, M S

    2006-01-01

    Pulmonary alveolar proteinosis is a rare syndrome characterized by intra-alveolar accumulation of surfactant components and cellular debris, with minimal interstitial inflammation or fibrosis. The condition has a variable clinical course, from spontaneous resolution to respiratory failure and death due to disease progression or superimposed infections. The standard of care for alveolor proteinosis therapy is represented by whole lung lavage. Important discoveries have been made in the last decade with respect to disease pathogenesis and therapy of both congenital and acquired forms of the disease. Granulocyte-macrophage colony-stimulating factor (GM-CSF) pathway has been shown to be involved in the disease pathogenesis of both acquired and congenital disease. Furthermore, anti-GM-CSF blocking autoantibodies have been found in the serum and bronchoalveolar lavage fluid and seem to interfere with the surfactant clearance by alveolar macrophages in many acquired cases. In the congenital form, the most common defects identified to date are several mutations of the genes encoding GM-CSF receptor subunits or surfactant proteins. Using GM-CSF as a therapeutic tool has also been shown to be effective in at least half of the acquired cases treated, while the importance of quantitative determination of anti-GM-CSF antibodies before and during the course of the therapy, as well as the autoantibody titer-GM-CSF dose relationship are to be elucidated. The congenital form of the disease does not respond to therapy with GM-CSF, consistent with the known primary defects and differences in disease pathogenesis. PMID:16916009

  5. Alveolar Capillary Dysplasia

    PubMed Central

    Stankiewicz, Pawel; Steinhorn, Robin H.

    2011-01-01

    Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare, fatal developmental lung disorder of neonates and infants. This review aims to address recent findings in the etiology and genetics of ACD/MPV and to raise awareness of this poorly known disease, which may also present as milder, unclassified forms. Successively discussed are what is known about the epidemiology, pathogenesis, pathophysiology, diagnostic indicators and approaches, genetic testing, treatment, and cases of delayed onset. The review concludes with suggestions for future directions to answer the many unknowns about this disorder. PMID:21471096

  6. Alveolar rhabdomyosarcoma of maxilla

    PubMed Central

    Ananthaneni, Anuradha; Kuberappa, Puneeth Horatti; Srinivas, G Vijay; Kiresur, Mohammad Asif

    2016-01-01

    Rhabdomyosarcoma (RMS), a malignant neoplasm of skeletal muscle origin, is the most common soft tissue sarcoma seen in childhood and adolescence. The most frequent site is the head and neck accounting for 40% of all cases and other involved sites are genitourinary tract, retroperitoneum, and to a lesser extent, the extremities. RMS is relatively uncommon in the oral cavity and the involvement of the jaws is extremely rare. Here, we report a case of 50-year-old female with oral RMS involving maxillary alveolar region with clinical, radiological, histopathological and immunohistochemical findings. PMID:27194887

  7. Alveolar rhabdomyosarcoma of maxilla.

    PubMed

    Ananthaneni, Anuradha; Kuberappa, Puneeth Horatti; Srinivas, G Vijay; Kiresur, Mohammad Asif

    2016-01-01

    Rhabdomyosarcoma (RMS), a malignant neoplasm of skeletal muscle origin, is the most common soft tissue sarcoma seen in childhood and adolescence. The most frequent site is the head and neck accounting for 40% of all cases and other involved sites are genitourinary tract, retroperitoneum, and to a lesser extent, the extremities. RMS is relatively uncommon in the oral cavity and the involvement of the jaws is extremely rare. Here, we report a case of 50-year-old female with oral RMS involving maxillary alveolar region with clinical, radiological, histopathological and immunohistochemical findings. PMID:27194887

  8. Pulmonary Alveolar Proteinosis Syndrome.

    PubMed

    Suzuki, Takuji; Trapnell, Bruce C

    2016-09-01

    Pulmonary alveolar proteinosis (PAP) is a rare syndrome characterized by the accumulation of surfactant in alveoli and terminal airways resulting in respiratory failure. PAP comprises part of a spectrum of disorders of surfactant homeostasis (clearance and production). The surfactant production disorders are caused by mutations in genes required for normal surfactant production. The PAP syndrome is identified based on history, radiologic, and bronchoalveolar lavage and/or histopathologic findings. The diagnosis of PAP-causing diseases in secondary PAP requires further studies. Whole-lung lavage is the current standard therapy and promising new pharmacologic therapies are in development. PMID:27514590

  9. Pulmonary Alveolar Microlithiasis

    PubMed Central

    Mehta, Kevan; Dell, Sharon; Birken, Catherine; Al-Saleh, Suhail

    2016-01-01

    Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive condition that is often asymptomatic despite significant changes in chest imaging. Diagnosis is often made when patients become symptomatic in adulthood. There are still no proven treatments, but earlier diagnosis may allow for evaluation of preventative strategies that could improve outcome. It is an important diagnosis to consider in children who have marked radiographic findings with no or very mild symptoms or physical findings. Diagnosis can be made with imaging alone but may necessitate lung biopsy for definitive diagnosis. PMID:27445543

  10. p120-Catenin Expressed in Alveolar Type II Cells Is Essential for the Regulation of Lung Innate Immune Response

    PubMed Central

    Chignalia, Andreia Z.; Vogel, Stephen M.; Reynolds, Albert B.; Mehta, Dolly; Dull, Randal O.; Minshall, Richard D.; Malik, Asrar B.; Liu, Yuru

    2016-01-01

    The integrity of the lung alveolar epithelial barrier is required for the gas exchange and is important for immune regulation. Alveolar epithelial barrier is composed of flat type I cells, which make up approximately 95% of the gas-exchange surface, and cuboidal type II cells, which secrete surfactants and modulate lung immunity. p120-catenin (p120; gene symbol CTNND1) is an important component of adherens junctions of epithelial cells; however, its function in lung alveolar epithelial barrier has not been addressed in genetic models. Here, we created an inducible type II cell–specific p120-knockout mouse (p120EKO). The mutant lungs showed chronic inflammation, and the alveolar epithelial barrier was leaky to 125I-albumin tracer compared to wild type. The mutant lungs also demonstrated marked infiltration of inflammatory cells and activation of NF-κB. Intracellular adhesion molecule 1, Toll-like receptor 4, and macrophage inflammatory protein 2 were all up-regulated. p120EKO lungs showed increased expression of the surfactant proteins Sp-B, Sp-C, and Sp-D, and displayed severe inflammation after pneumonia caused by Pseudomonas aeruginosa compared with wild type. In p120-deficient type II cell monolayers, we observed reduced transepithelial resistance compared to control, consistent with formation of defective adherens junctions. Thus, although type II cells constitute only 5% of the alveolar surface area, p120 expressed in these cells plays a critical role in regulating the innate immunity of the entire lung. PMID:25773174

  11. p120-catenin expressed in alveolar type II cells is essential for the regulation of lung innate immune response.

    PubMed

    Chignalia, Andreia Z; Vogel, Stephen M; Reynolds, Albert B; Mehta, Dolly; Dull, Randal O; Minshall, Richard D; Malik, Asrar B; Liu, Yuru

    2015-05-01

    The integrity of the lung alveolar epithelial barrier is required for the gas exchange and is important for immune regulation. Alveolar epithelial barrier is composed of flat type I cells, which make up approximately 95% of the gas-exchange surface, and cuboidal type II cells, which secrete surfactants and modulate lung immunity. p120-catenin (p120; gene symbol CTNND1) is an important component of adherens junctions of epithelial cells; however, its function in lung alveolar epithelial barrier has not been addressed in genetic models. Here, we created an inducible type II cell-specific p120-knockout mouse (p120EKO). The mutant lungs showed chronic inflammation, and the alveolar epithelial barrier was leaky to (125)I-albumin tracer compared to wild type. The mutant lungs also demonstrated marked infiltration of inflammatory cells and activation of NF-κB. Intracellular adhesion molecule 1, Toll-like receptor 4, and macrophage inflammatory protein 2 were all up-regulated. p120EKO lungs showed increased expression of the surfactant proteins Sp-B, Sp-C, and Sp-D, and displayed severe inflammation after pneumonia caused by Pseudomonas aeruginosa compared with wild type. In p120-deficient type II cell monolayers, we observed reduced transepithelial resistance compared to control, consistent with formation of defective adherens junctions. Thus, although type II cells constitute only 5% of the alveolar surface area, p120 expressed in these cells plays a critical role in regulating the innate immunity of the entire lung. PMID:25773174

  12. Biology of alveolar type II cells.

    PubMed

    Mason, Robert J

    2006-01-01

    The purpose of this review is to highlight the many metabolic properties of alveolar type II cells, their production of surfactant, their role in innate immunity, and their importance in the repair process after lung injury. The review is based on the medical literature and results from our laboratory. Type II cells produce and secrete pulmonary surfactant and for that purpose they need to synthesize the lipids of surfactant. One of the regulators of lipogenesis is the transcription factor sterol regulatory element binding protein-1c (SREBP-1c). This is a key transcription factor regulating fatty acid synthesis. Type II cells also proliferate to restore the epithelium after lung injury, clear alveolar fluid by transporting sodium from the apical to the basolateral surface, and participate in the innate immune response to inhaled materials and organisms. The type II cell is, in many ways, the defender of the alveolus. However, the type II cells work in concert with the other cells in the gas exchange regions of the lung to keep the alveoli open and reduce inflammation due to irritants in the air we breathe. PMID:16423262

  13. CUX1/Wnt signaling regulates Epithelial Mesenchymal Transition in EBV infected epithelial cells

    SciTech Connect

    Malizia, Andrea P.; Lacey, Noreen; Walls, Dermot; Egan, Jim J.; Doran, Peter P.

    2009-07-01

    Idiopathic pulmonary fibrosis (IPF) is a refractory and lethal interstitial lung disease characterized by alveolar epithelial cells apoptosis, fibroblast proliferation and extra-cellular matrix protein deposition. EBV, localised to alveolar epithelial cells of pulmonary fibrosis patients is associated with a poor prognosis. A strategy based on microarray-differential gene expression analysis to identify molecular drivers of EBV-associated lung fibrosis was utilized. Alveolar epithelial cells were infected with EBV to identify genes whose expression was altered following TGF{beta}1-mediated lytic phase. EBV lytic reactivation by TGF{beta}1 drives a selective alteration in CUX1 variant (a) (NCBI accession number NM{sub 1}81552) expression, inducing activation of non-canonical Wnt pathway mediators, implicating it in Epithelial Mesenchymal Transition (EMT), the molecular event underpinning scar production in tissue fibrosis. The role of EBV in EMT can be attenuated by antiviral strategies and inhibition of Wnt signaling by using All-Trans Retinoic Acids (ATRA). Activation of non-canonical Wnt signaling pathway by EBV in epithelial cells suggests a novel mechanism of EMT via CUX1 signaling. These data present a framework for further description of the link between infectious agents and fibrosis, a significant disease burden.

  14. Pulmonary Administration of GW0742, a High-Affinity Peroxisome Proliferator-Activated Receptor Agonist, Repairs Collapsed Alveoli in an Elastase-Induced Mouse Model of Emphysema.

    PubMed

    Ozawa, Chihiro; Horiguchi, Michiko; Akita, Tomomi; Oiso, Yuki; Abe, Kaori; Motomura, Tomoki; Yamashita, Chikamasa

    2016-01-01

    Pulmonary emphysema is a disease in which lung alveoli are irreversibly damaged, thus compromising lung function. Our previous study revealed that all-trans-retinoic acid (ATRA) induces the differentiation of human lung alveolar epithelial type 2 progenitor cells and repairs the alveoli of emphysema model mice. ATRA also reportedly has the ability to activate peroxisome proliferator-activated receptor (PPAR) β/δ. A selective PPARβ/δ ligand has been reported to induce the differentiation of human keratinocytes during wound repair. Here, we demonstrate that treatment using a high-affinity PPARβ/δ agonist, GW0742, reverses the lung tissue damage induced by elastase in emphysema-model mice and improves respiratory function. Mice treated with elastase, which collapsed their alveoli, were then treated with either 10% dimethyl sulfoxide (DMSO) in saline (control group) or GW0742 (1.0 mg/kg twice a week) by pulmonary administration. Treatment with GW0742 for 2 weeks increased the in vivo expression of surfactant proteins A and D, which are known alveolar type II epithelial cell markers. GW0742 treatment also shortened the average distance between alveolar walls in the lungs of emphysema model mice, compared with a control group treated with 10% DMSO in saline. Treatment with GW0742 for 3 weeks also improved tissue elastance (cm H2O/mL), as well as the ratio of the forced expiratory volume in the first 0.05 s to the forced vital capacity (FEV 0.05/FVC). In each of these experiments, GW0742 treatment reversed the damage caused by elastase. In conclusion, PPARβ/δ agonists are potential therapeutic agents for pulmonary emphysema. PMID:27150147

  15. Autophagy regulates hyperoxia-induced intracellular accumulation of surfactant protein C in alveolar type II cells.

    PubMed

    Zhang, Liang; Zhao, Shuang; Yuan, Li-Jie; Wu, Hong-Min; Jiang, Hong; Zhao, Shi-Meng; Luo, Gang; Xue, Xin-Dong

    2015-10-01

    Surfactant protein C (SP-C) deficiency is a risk factor for hyperoxia-induced bronchopulmonary dysplasia in newborn infants. However, the role of SP-C deficiency in the process is unclear. Here, using neonatal rat BPD model and MLE-12, mouse alveolar epithelial type II cell, we examined the changes of SP-C levels during hyperoxia. Immunohistochemistry, immunofluorescence, and ELISA analysis showed SP-C accumulation in alveolar epithelial type II cells. Electron microscopy further demonstrated the accumulation of lamellar bodies and the co-localization of lamellar bodies with autophagosomes in the cytoplasm of alveolar epithelial type II cells. The inhibition of autophagy with 3-Methyladenine and knockdown of Atg7 abolished hyperoxia-induced SP-C accumulation in the cytoplasm. Furthermore, inhibition of JNK signaling with SP600125 suppressed hyperoxia-induced Atg7 expression and SP-C accumulation. These findings suggest that hyperoxia triggers autophagy via JNK signaling-mediated Atg7 expression, which promotes the accumulation of SP-C within alveolar epithelial type II cells. Our data provide a potential approach for hyperoxic lung injury therapy by targeted pharmacological inhibition of autophagic pathway. PMID:26122393

  16. The development and plasticity of alveolar type 1 cells.

    PubMed

    Yang, Jun; Hernandez, Belinda J; Martinez Alanis, Denise; Narvaez del Pilar, Odemaris; Vila-Ellis, Lisandra; Akiyama, Haruhiko; Evans, Scott E; Ostrin, Edwin J; Chen, Jichao

    2016-01-01

    Alveolar type 1 (AT1) cells cover >95% of the gas exchange surface and are extremely thin to facilitate passive gas diffusion. The development of these highly specialized cells and its coordination with the formation of the honeycomb-like alveolar structure are poorly understood. Using new marker-based stereology and single-cell imaging methods, we show that AT1 cells in the mouse lung form expansive thin cellular extensions via a non-proliferative two-step process while retaining cellular plasticity. In the flattening step, AT1 cells undergo molecular specification and remodel cell junctions while remaining connected to their epithelial neighbors. In the folding step, AT1 cells increase in size by more than 10-fold and undergo cellular morphogenesis that matches capillary and secondary septa formation, resulting in a single AT1 cell spanning multiple alveoli. Furthermore, AT1 cells are an unexpected source of VEGFA and their normal development is required for alveolar angiogenesis. Notably, a majority of AT1 cells proliferate upon ectopic SOX2 expression and undergo stage-dependent cell fate reprogramming. These results provide evidence that AT1 cells have both structural and signaling roles in alveolar maturation and can exit their terminally differentiated non-proliferative state. Our findings suggest that AT1 cells might be a new target in the pathogenesis and treatment of lung diseases associated with premature birth. PMID:26586225

  17. Alveolar bone grafting

    PubMed Central

    Lilja, Jan

    2009-01-01

    In patients with cleft lip and palate, bone grafting in the mixed dentition in the residual alveolar cleft has become a well-established procedure. The main advantages can be summarised as follows: stabilisation of the maxillary arch; facilitation of eruption of the canine and sometimes facilitation of the lateral incisor eruption; providing bony support to the teeth adjacent to the cleft; raising the alar base of the nose; facilitation of closure of an oro-nasal fistula; making it possible to insert a titanium fixture in the grafted site and to obtain favourable periodontal conditions of the teeth within and adjacent to the cleft. The timing of the ABG surgery take into consideration not only eruption of the canine but also that of the lateral incisor, if present. The best time for bone grafting surgery is when a thin shell of bone still covers the soon erupting lateral incisor or canine tooth close to the cleft. PMID:19884665

  18. Dehydroepiandrosterone inhibits the spontaneous release of superoxide radical by alveolar macrophages in vitro in asbestosis

    SciTech Connect

    Rom, W.N.; Harkin, T. )

    1991-08-01

    Asbestosis is characterized by an alveolar macrophage alveolitis with injury and fibrosis of the lower respiratory tract. Alveolar macrophages recovered by bronchoalveolar lavage spontaneously release exaggerated amounts of oxidants including superoxide anion and hydrogen peroxide that may mediate alveolar epithelial cell injury. Dehydroepiandrosterone (DHEA) is a normally occurring adrenal androgen that inhibits glucose-6-phosphate dehydrogenase, the initial enzyme in the pentose phosphate shunt necessary for NADPH generation and superoxide anion formation. In this regard, the authors hypothesized that DHEA may reduce asbestos-induced oxidant release. DHEA added in vitro to alveolar macrophages lavaged from 11 nonsmoking asbestos workers significantly reduced superoxide anion release. DHEA is an antioxidant and potential anticarcinogenic agent that may have a therapeutic role in reducing the increased oxidant burden in asbestos-induced alveolitis of the lower respiratory tract.

  19. Resveratrol mediated cell death in cigarette smoke transformed breast epithelial cells is through induction of p21Waf1/Cip1 and inhibition of long patch base excision repair pathway

    SciTech Connect

    Mohapatra, Purusottam; Satapathy, Shakti Ranjan; Das, Dipon; Siddharth, Sumit; Choudhuri, Tathagata; Kundu, Chanakya Nath

    2014-03-15

    Cigarette smoking is a key factor for the development and progression of different cancers including mammary tumor in women. Resveratrol (Res) is a promising natural chemotherapeutic agent that regulates many cellular targets including p21, a cip/kip family of cyclin kinase inhibitors involved in DNA damage-induced cell cycle arrest and blocking of DNA replication and repair. We have recently shown that cigarette smoke condensate (CSC) prepared from commercially available Indian cigarette can cause neoplastic transformation of normal breast epithelial MCF-10A cell. Here we studied the mechanism of Res mediated apoptosis in CSC transformed (MCF-10A-Tr) cells in vitro and in vivo. Res mediated apoptosis in MCF-10A-Tr cells was a p21 dependent event. It increased the p21 protein expression in MCF-10A-Tr cells and MCF-10A-Tr cells-mediated tumors in xenograft mice. Res treatment reduced the tumor size(s) and expression of anti-apoptotic proteins (e.g. PI3K, AKT, NFκB) in solid tumor. The expressions of cell cycle regulatory (Cyclins, CDC-2, CDC-6, etc.), BER associated (Pol-β, Pol-δ, Pol-ε, Pol-η, RPA, Fen-1, DNA-Ligase-I, etc.) proteins and LP-BER activity decreased in MCF-10A-Tr cells but remain significantly unaltered in isogenic p21 null MCF-10A-Tr cells after Res treatment. Interestingly, no significant changes were noted in SP-BER activity in both the cell lines after Res exposure. Finally, it was observed that increased p21 blocks the LP-BER in MCF-10A-Tr cells by increasing its interaction with PCNA via competing with Fen-1 after Res treatment. Thus, Res caused apoptosis in CSC-induced cancer cells by reduction of LP-BER activity and this phenomenon largely depends on p21. - Highlights: • Resveratrol (Res) caused reduction of MCF-10A-Tr cell growth by inducing apoptosis. • Res caused cell cycle arrest and DNA damage in p21 dependent manner. • Res mediated LP-BER reduction in MCF-10A-Tr cells was a p21 dependent phenomenon. • Res inhibits BER and PI

  20. DNA repair

    SciTech Connect

    Friedberg, E.C.; Hanawalt, P.C. )

    1988-01-01

    Topics covered in this book included: Eukaryote model systems for DNA repair study; Sensitive detection of DNA lesions and their repair; and Defined DNA sequence probes for analysis of mutagenesis and repair.

  1. Particle-induced indentation of the alveolar epithelium caused by surface tension forces.

    PubMed

    Mijailovich, S M; Kojic, M; Tsuda, A

    2010-10-01

    Physical contact between an inhaled particle and alveolar epithelium at the moment of particle deposition must have substantial effects on subsequent cellular functions of neighboring cells, such as alveolar type-I, type-II pneumocytes, alveolar macrophage, as well as afferent sensory nerve cells, extending their dendrites toward the alveolar septal surface. The forces driving this physical insult are born at the surface of the alveolar air-liquid layer. The role of alveolar surfactant submerging a hydrophilic particle has been suggested by Gehr and Schürch's group (e.g., Respir Physiol 80: 17-32, 1990). In this paper, we extended their studies by developing a further comprehensive and mechanistic analysis. The analysis reveals that the mechanics operating in the particle-tissue interaction phenomena can be explained on the basis of a balance between surface tension force and tissue resistance force; the former tend to move a particle toward alveolar epithelial cell surface, the latter to resist the cell deformation. As a result, the submerged particle deforms the tissue and makes a noticeable indentation, which creates unphysiological stress and strain fields in tissue around the particle. This particle-induced microdeformation could likely trigger adverse mechanotransduction and mechanosensing pathways, as well as potentially enhancing particle uptake by the cells. PMID:20634359

  2. Particle-induced indentation of the alveolar epithelium caused by surface tension forces

    PubMed Central

    Kojic, M.; Tsuda, A.

    2010-01-01

    Physical contact between an inhaled particle and alveolar epithelium at the moment of particle deposition must have substantial effects on subsequent cellular functions of neighboring cells, such as alveolar type-I, type-II pneumocytes, alveolar macrophage, as well as afferent sensory nerve cells, extending their dendrites toward the alveolar septal surface. The forces driving this physical insult are born at the surface of the alveolar air-liquid layer. The role of alveolar surfactant submerging a hydrophilic particle has been suggested by Gehr and Schürch's group (e.g., Respir Physiol 80: 17–32, 1990). In this paper, we extended their studies by developing a further comprehensive and mechanistic analysis. The analysis reveals that the mechanics operating in the particle-tissue interaction phenomena can be explained on the basis of a balance between surface tension force and tissue resistance force; the former tend to move a particle toward alveolar epithelial cell surface, the latter to resist the cell deformation. As a result, the submerged particle deforms the tissue and makes a noticeable indentation, which creates unphysiological stress and strain fields in tissue around the particle. This particle-induced microdeformation could likely trigger adverse mechanotransduction and mechanosensing pathways, as well as potentially enhancing particle uptake by the cells. PMID:20634359

  3. Expression of β-Defensin Genes in Bovine Alveolar Macrophages

    PubMed Central

    Ryan, Lisa K.; Rhodes, Janice; Bhat, Meenakshi; Diamond, Gill

    1998-01-01

    Bovine alveolar macrophages (BAM) were examined for the expression of β-defensins and to determine whether their expression could be upregulated by bacterial lipopolysaccharide (LPS), as observed with β-defensins expressed in bovine tracheal epithelial cells. Four β-defensins were expressed constitutively in BAM, with bovine neutrophil β-defensin (BNBD)-4 and BNBD-5 being the most predominant. This is the first evidence of β-defensin gene expression in a mature myeloid cell. LPS had no effect on β-defensin expression in BAM, even though tumor necrosis factor alpha (TNF-α) production was induced. Nonbacterial inflammatory particles had little effect on β-defensin gene expression or TNF-α production in BAM. We hypothesize that constitutively expressed β-defensins of alveolar macrophages may have a role in lung host defense. PMID:9453661

  4. PPARs in alveolar macrophage biology.

    PubMed

    Smith, Monica R; Standiford, Theodore J; Reddy, Raju C

    2007-01-01

    PPARs, most notably PPAR-gamma, play a crucial role in regulating the activation of alveolar macrophages, which in turn occupy a pivotal place in the immune response to pathogens and particulates drawn in with inspired air. In this review, we describe the dual role of the alveolar macrophage as both a first-line defender through its phagocytotic activity and a regulator of the immune response. Depending on its state of activation, the alveolar macrophage may either enhance or suppress different aspects of immune function in the lung. We then review the role of PPAR-gamma and its ligands in deactivating alveolar macrophages-thus limiting the inflammatory response that, if unchecked, could threaten the essential respiratory function of the alveolus-while upregulating the cell's phagocytotic activity. Finally, we examine the role that inadequate or inappropriate PPAR-gamma responses play in specific lung diseases. PMID:18000531

  5. Claudins: Gatekeepers of lung epithelial function.

    PubMed

    Schlingmann, Barbara; Molina, Samuel A; Koval, Michael

    2015-06-01

    The lung must maintain a proper barrier between airspaces and fluid filled tissues in order to maintain lung fluid balance. Central to maintaining lung fluid balance are epithelial cells which create a barrier to water and solutes. The barrier function of these cells is mainly provided by tight junction proteins known as claudins. Epithelial barrier function varies depending on the different needs within the segments of the respiratory tree. In the lower airways, fluid is required to maintain mucociliary clearance, whereas in the terminal alveolar airspaces a thin layer of surfactant enriched fluid lowers surface tension to prevent airspace collapse and is critical for gas exchange. As the epithelial cells within the segments of the respiratory tree differ, the composition of claudins found in these epithelial cells is also different. Among these differences is claudin-18 which is uniquely expressed by the alveolar epithelial cells. Other claudins, notably claudin-4 and claudin-7, are more ubiquitously expressed throughout the respiratory epithelium. Claudin-5 is expressed by both pulmonary epithelial and endothelial cells. Based on in vitro and in vivo model systems and histologic analysis of lungs from human patients, roles for specific claudins in maintaining barrier function and protecting the lung from the effects of acute injury and disease are being identified. One surprising finding is that claudin-18 and claudin-4 control lung cell phenotype and inflammation beyond simply maintaining a selective paracellular permeability barrier. This suggests claudins have more nuanced roles for the control of airway and alveolar physiology in the healthy and diseased lung. PMID:25951797

  6. Micronuclei in human alveolar macrophages.

    PubMed

    D'Agostini, F; Bonatti, S; Oddera, S; De Flora, S

    1992-01-01

    Occurrence of micronuclei was monitored in pulmonary alveolar macrophages collected from 31 individuals undergoing diagnostic bronchoalveolar lavage. The overall frequency of micronucleated cells was 3.88 +/- 1.84/1000, without any significant difference attributable to sex, age, pathology, occupation, or smoking habits. The lack of influence of cigarette smoke on this clastogenicity index presumably reflects the very low rate of mitoses of macrophages in the alveolar lumen. PMID:1579732

  7. Laser Microdissection of the Alveolar Duct Enables Single-Cell Genomic Analysis

    PubMed Central

    Bennett, Robert D.; Ysasi, Alexandra B.; Belle, Janeil M.; Wagner, Willi L.; Konerding, Moritz A.; Blainey, Paul C.; Pyne, Saumyadipta; Mentzer, Steven J.

    2014-01-01

    Complex tissues such as the lung are composed of structural hierarchies such as alveoli, alveolar ducts, and lobules. Some structural units, such as the alveolar duct, appear to participate in tissue repair as well as the development of bronchioalveolar carcinoma. Here, we demonstrate an approach to conduct laser microdissection of the lung alveolar duct for single-cell PCR analysis. Our approach involved three steps. (1) The initial preparation used mechanical sectioning of the lung tissue with sufficient thickness to encompass the structure of interest. In the case of the alveolar duct, the precision-cut lung slices were 200 μm thick; the slices were processed using near-physiologic conditions to preserve the state of viable cells. (2) The lung slices were examined by transmission light microscopy to target the alveolar duct. The air-filled lung was sufficiently accessible by light microscopy that counterstains or fluorescent labels were unnecessary to identify the alveolar duct. (3) The enzymatic and microfluidic isolation of single cells allowed for the harvest of as few as several thousand cells for PCR analysis. Microfluidics based arrays were used to measure the expression of selected marker genes in individual cells to characterize different cell populations. Preliminary work suggests the unique value of this approach to understand the intra- and intercellular interactions within the regenerating alveolar duct. PMID:25309876

  8. Inferior alveolar nerve repositioning.

    PubMed

    Louis, P J

    2001-09-01

    Nerve repositioning is a viable alternative for patients with an atrophic edentulous posterior mandible. Patients, however, should be informed of the potential risks of neurosensory disturbance. Documentation of the patient's baseline neurosensory function should be performed with a two-point discrimination test or directional brush stroke test preoperatively and postoperatively. Recovery of nerve function should be expected in 3 to 6 months. The potential for mandibular fracture when combining nerve repositioning with implant placement also should be discussed with the patient. This can be avoided by minimizing the amount of buccal cortical plate removal during localization of the nerve and maintaining the integrity of the inferior cortex of the mandible. Additionally, avoid overseating the implant, thus avoiding stress along the inferior border of the mandible. The procedure does allow for the placement of longer implants, which should improve implant longevity. Patients undergoing this procedure have expressed overall satisfaction with the results. Nerve repositioning also can be used to preserve the inferior alveolar nerve during resection of benign tumors or cysts of the mandible. This procedure allows the surgeon to maintain nerve function in situations in which the nerve would otherwise have to be resected. PMID:11665379

  9. Micromechanics of alveolar edema.

    PubMed

    Perlman, Carrie E; Lederer, David J; Bhattacharya, Jahar

    2011-01-01

    The decrease of lung compliance in pulmonary edema underlies ventilator-induced lung injury. However, the cause of the decrease in compliance is unknown. We tested the hypothesis that in pulmonary edema, the mechanical effects of liquid-filled alveoli increase tissue stress in adjacent air-filled alveoli. By micropuncture of isolated, perfused rat lungs, we established a single-alveolus model of pulmonary edema that we imaged using confocal microscopy. In this model, we viewed a liquid-filled alveolus together with its air-filled neighbor at different transpulmonary pressures, both before and after liquid-filling. Instilling liquid in an alveolus caused alveolar shrinkage. As a result, the interalveolar septum was stretched, causing the neighboring air-filled alveolus to bulge. Thus, the air-filled alveolus was overexpanded by virtue of its adjacency to a liquid-filled alveolus. Confocal microscopy at different depths of the liquid-filled alveolus revealed a meniscus. Lung inflation to near-total lung capacity (TLC) demonstrated decreased compliance of the air-filled but not liquid-filled alveolus. However, at near TLC, the air-filled alveolus was larger than it was in the pre-edematous control tissue. In pulmonary edema, liquid-filled alveoli induce mechanical stress on air-filled alveoli, reducing the compliance of air-filled alveoli, and hence overall lung compliance. Because of increased mechanical stress, air-filled alveoli may be susceptible to overdistension injury during mechanical ventilation of the edematous lung. PMID:20118224

  10. New insights of P2X7 receptor signaling pathway in alveolar functions.

    PubMed

    Mishra, Amarjit

    2013-01-01

    Purinergic P2X7 receptor (P2X7R), an ATP-gated cation channel, is unique among all other family members because of its ability to respond to various stimuli and to modulate pro-inflammatory signaling. The activation of P2X7R in immune cells is absolutely required for mature interleukin -1beta (IL-1beta) and IL-18 production and release. Lung alveoli are lined by the structural alveolar epithelial type I (AEC I) and alveolar epithelial type II cells (AEC II). AEC I plays important roles in alveolar barrier protection and fluid homeostasis whereas AEC II synthesizes and secrete surfactant and prevents alveoli from collapse. Earlier studies indicated that purinergic P2X7 receptors were specifically expressed in AEC I. However, their implication in alveolar functions has not been explored. This paper reviews two important signaling pathways of P2X7 receptors in surfactant homeostatsis and Acute Lung Injury (ALI). Thus, P2X7R resides at the critical nexus of alveo