Expression of the beta 6 integrin subunit in development, neoplasia and tissue repair suggests a role in epithelial remodeling

The alpha v beta 6 integrin was identified in cultured epithelial cells and functions as a fibronectin receptor. We have now used monoclonal antibodies to determine in vivo expression patterns of the beta 6 subunit in normal and pathological human or primate tissues, and during experimental wound healing or induced lung injury. The results indicate that beta 6 expression is restricted to epithelia and is up-regulated in parallel with morphogenetic events, tumorigenesis, and epithelial repair. During development of the kidney, lung, and skin, we found that beta 6 is expressed by specific types of epithelial cells, whereas it is mostly undetectable in normal adult kidney, lung and skin. In contrast, we detected high-level expression in several types of carcinoma. For example, beta 6 is almost invariably neo-expressed in squamous cell carcinomas derived from the oral mucosa, often focally localized at the infiltrating edges of tumor islands. Expression of beta 6 is also upregulated in migrating keratinocytes at the wound edge during experimental epidermal wound healing. Similarly, beta 6 expression is induced in type II alveolar epithelial cells during lung injury caused by injection of live bacteria. We also observed beta 6 expression in adult lungs and kidneys at focal sites of subclinical inflammation, as well as in a variety of clinical specimens from patients with chronic or acute inflammation of the lungs or kidneys. From these findings and earlier results, we hypothesize that alpha v beta 6 affects cell spreading, migration and growth during reorganization of epithelia in development, tissue repair, and neoplasia.

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Exosomes Derived From Alveolar Epithelial Cells Promote Alveolar Macrophage Activation Mediated by miR-92a-3p in Sepsis-Induced Acute Lung Injury

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.646546 ◽

2021 ◽

Vol 11 ◽

Author(s):

Fen Liu ◽

Wei Peng ◽

Jiaquan Chen ◽

Zeyao Xu ◽

Rong Jiang ◽

...

Keyword(s):

Acute Lung Injury ◽

Epithelial Cells ◽

Lung Injury ◽

Pulmonary Inflammation ◽

Cecal Ligation ◽

Alveolar Epithelial Cells ◽

Luciferase Reporter ◽

Alveolar Epithelial

Acute lung injury (ALI) induced by sepsis is characterized by disruption of the epithelial barrier and activation of alveolar macrophages (AMs), which leads to uncontrolled pulmonary inflammation. However, effective treatments for ALI are unavailable. The exact mechanism by which the initial mediator of alveolar epithelial cells (AECs) induces inflammation remains elusive. Here we investigated the roles of AEC-derived exosomes in AM activation and sepsis-induced ALI in vivo and in vitro. Cecal ligation and puncture (CLP) was utilized to establish septic lung injury model in rats. The effect of exosomal inhibition by intratracheal GW4869 administration on lung injury was investigated. To assess the effects of AEC-derived exosomes on ALI, we treated the rat alveolar epithelial cell line RLE-6TN with LPS to induce cell damage. Exosomes from conditioned medium of LPS-treated AECs (LPS-Exos) were isolated by ultracentrifugation. The miRNAs in LPS-Exos were screened by miRNA expression profile analysis. The effects of miR-92a-3p on the function of AMs were studied. We found that intratracheal GW4869 administration ameliorated lung injury following CLP-induced ALI. LPS-Exos were taken up by AMs and activated these cells. Consistently, administration of LPS-Exos in rats significantly aggravated pulmonary inflammation and alveolar permeability. Moreover, miR-92a-3p was enriched in LPS-Exos and could be delivered to AMs. Inhibition of miR-92a-3p in AECs diminished the proinflammatory effects of LPS-Exos in vivo and in vitro. Mechanistically, miR-92a-3p activates AMs along with pulmonary inflammation. This process results in activation of the NF-κB pathway and downregulation of PTEN expression, which was confirmed by a luciferase reporter assay. In conclusion, AEC-derived exosomes activate AMs and induce pulmonary inflammation mediated by miR-92a-3p in ALI. The present findings revealed a previously unidentified role of exosomal miR-92a-3p in mediating the crosstalk between injured AEC and AMs. miR-92a-3p in AEC exosomes might represent a novel diagnostic biomarker for ALI, which may lead to a new therapeutic approach.

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In vivo mitogenic action of HGF on lung epithelial cells: pulmotrophic role in lung regeneration

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1996.270.6.l1031 ◽

1996 ◽

Vol 270 (6) ◽

pp. L1031-L1039 ◽

Cited By ~ 17

Author(s):

H. Ohmichi ◽

K. Matsumoto ◽

T. Nakamura

Keyword(s):

Acute Lung Injury ◽

Epithelial Cells ◽

Lung Injury ◽

Dna Synthesis ◽

Airway Epithelial Cells ◽

Alveolar Epithelial Cells ◽

Alveolar Epithelial ◽

Lung Regeneration

Hepatocyte growth factor (HGF) has mitogenic, morphogenic, and motogenic activities on epithelial cells and plays important roles in regeneration of the liver and the kidney. We previously found that the expression of HGF gene is rapidly induced in the lung after acute lung injury in experimental animals and that HGF levels are elevated in blood of patients with lung diseases. To search for a possible pulmotrophic function of HGF in lung regeneration, we examined the mitogenic activity of HGF on tracheal epithelial cells in vitro and evaluated the efficacy of HGF-administration on lung regeneration after acute lung injury in mice. HGF markedly stimulated proliferation and DNA synthesis of rat tracheal epithelial cells in primary culture in a dose-dependent manner. The intravenous injection of human recombinant HGF (10 micrograms.mouse-1.day-1) into mice with acute lung injury induced by the intratracheal infusion of 10 mM HCI stimulated DNA synthesis of airway epithelial cells to levels threefold higher than those in mice with no HGF-injections, but it did not stimulate DNA synthesis of alveolar epithelial cells. However, HGF injection at higher dose (100 micrograms.mouse-1.day-1) stimulated DNA synthesis of alveolar epithelial cells in vivo. These results indicate that HGF is a potent mitogen for airway epithelial cells and alveolar epithelial cells in vivo as well as in vitro. HGF may act as pulmotrophic factor responsible for airway and alveolar regeneration during lung regeneration after acute lung injury.

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The cellular kinetics of lung alveolar epithelial cells and its relationship with lung tissue repair after acute lung injury

Respiratory Research ◽

10.1186/s12931-016-0480-y ◽

2016 ◽

Vol 17 (1) ◽

Cited By ~ 10

Author(s):

Ling Zeng ◽

Xue-tao Yang ◽

Hai-sheng Li ◽

Yong Li ◽

Ce Yang ◽

...

Keyword(s):

Acute Lung Injury ◽

Epithelial Cells ◽

Lung Injury ◽

Lung Tissue ◽

Tissue Repair ◽

Alveolar Epithelial Cells ◽

Alveolar Epithelial ◽

Cellular Kinetics ◽

Kinetics Of

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Nano-Curcumin Regulates p53 Phosphorylation and PAI-1 Expression during Bleomycin Induced Injury in Alveolar Basal Epithelial Cells

Current Bioactive Compounds ◽

10.2174/1573407214666180727093612 ◽

2020 ◽

Vol 16 (1) ◽

pp. 85-89

Author(s):

Mahesh M. Gouda ◽

Ashwini Prabhu ◽

Varsha Reddy S.V. ◽

Rafa Jahan ◽

Yashodhar P. Bhandary

Keyword(s):

Epithelial Cells ◽

Lung Injury ◽

Molecular Mechanisms ◽

A549 Cells ◽

Plasminogen Activator Inhibitor ◽

Underlying Mechanism ◽

Protective Role ◽

Alveolar Epithelial Cells ◽

Cellular Damage

Background: Bleomycin (BLM) is known to cause DNA damage in the Alveolar Epithelial Cells (AECs). It is reported that BLM is involved in the up-regulation of inflammatory molecules such as neutrophils, macrophages, chemokines and cytokines. The complex underlying mechanism for inflammation mediated progression of lung injury is still unclear. This investigation was designed to understand the molecular mechanisms associated with p53 mediated modulation of Plasminogen Activator Inhibitor-I (PAI-I) expression and its regulation by nano-curcumin formulation. Methods: A549 cells were treated with BLM to cause the cellular damage in vitro and commercially available nano-curcumin formulation was used as an intervention. Cytotoxic effect of nano-curcumin was analyzed using Methyl Thiazolyl Tetrazolium (MTT) assay. Protein expressions were analyzed using western blot to evaluate the p53 mediated changes in PAI-I expression. Results: Nano-curcumin showed cytotoxicity up to 88.5 % at a concentration of 20 μg/ml after 48 h of treatment. BLM exposure to the cells activated the phosphorylation of p53, which in turn increased PAII expression. Nano-curcumin treatment showed a protective role against phosphorylation of p53 and PAI-I expression, which in turn regulated the fibro-proliferative phase of injury induced by bleomycin. Conclusion: Nano-curcumin could be used as an effective intervention to regulate the severity of lung injury, apoptosis of AECs and fibro-proliferation during pulmonary injury.

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Overexpression of the Oral Mucosa-Specific microRNA-31 Promotes Skin Wound Closure

International Journal of Molecular Sciences ◽

10.3390/ijms20153679 ◽

2019 ◽

Vol 20 (15) ◽

pp. 3679 ◽

Cited By ~ 3

Author(s):

Lin Chen ◽

Alyne Simões ◽

Zujian Chen ◽

Yan Zhao ◽

Xinming Wu ◽

...

Keyword(s):

Wound Healing ◽

Oral Mucosa ◽

Wound Closure ◽

Expression Patterns ◽

Skin Wound ◽

Skin Wound Healing ◽

Specific Expression ◽

Keratinocyte Proliferation

Wounds within the oral mucosa are known to heal more rapidly than skin wounds. Recent studies suggest that differences in the microRNAome profiles may underlie the exceptional healing that occurs in oral mucosa. Here, we test whether skin wound-healing can be accelerating by increasing the levels of oral mucosa-specific microRNAs. A panel of 57 differentially expressed high expresser microRNAs were identified based on our previously published miR-seq dataset of paired skin and oral mucosal wound-healing [Sci. Rep. (2019) 9:7160]. These microRNAs were further grouped into 5 clusters based on their expression patterns, and their differential expression was confirmed by TaqMan-based quantification of LCM-captured epithelial cells from the wound edges. Of these 5 clusters, Cluster IV (consisting of 8 microRNAs, including miR-31) is most intriguing due to its tissue-specific expression pattern and temporal changes during wound-healing. The in vitro functional assays show that ectopic transfection of miR-31 consistently enhanced keratinocyte proliferation and migration. In vivo, miR-31 mimic treatment led to a statistically significant acceleration of wound closure. Our results demonstrate that wound-healing can be enhanced in skin through the overexpression of microRNAs that are highly expressed in the privileged healing response of the oral mucosa.

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Co-Transplantation of Skin-Derived Precursors and Collagen Sponge Facilitates Diabetic Wound Healing by Promoting Local Vascular Regeneration

Cellular Physiology and Biochemistry ◽

10.1159/000438537 ◽

2015 ◽

Vol 37 (5) ◽

pp. 1725-1737 ◽

Cited By ~ 15

Author(s):

Tingyu Ke ◽

Mei Yang ◽

Duo Mao ◽

Meifeng Zhu ◽

Yongzhe Che ◽

...

Keyword(s):

Wound Healing ◽

Wound Repair ◽

Expression Patterns ◽

Collagen Sponge ◽

Health Concern ◽

Diabetic Wound ◽

Paracrine Signalling ◽

Vascular Regeneration ◽

Diabetic Wound Healing

Background/Aims: Impaired diabetes wound healing can often lead to serious complications and remains a major health concern due to the lack of effective therapeutic approaches. Compromised angiogenesis, disrupted growth factor and cytokine activity are all attributable to diabetic wound healing impairment. The skin-derived precursors (SKPs) have been shown to differentiate into vascular and nerve cells, both of which are crucial components for wound repair. Given their easy accessibility and multipotency, the SKPs were proposed as an ideal therapeutic candidate for diabetic wound healing. Since the efficacy of cell therapy is limited by poor cell survival, collagen sponge was employed for better SKPs delivery. Methods: SKPs were isolated and transplanted directly to the wound areas of diabetic mice in the absence and presence of collagen sponge. The effects of SKPs and/or collagen sponge on diabetic wound healing were examined histologically as well as immunostaining of isolectin and α-SMA. Mechanisms via which the SKPs facilitate wound healing were then investigated by transplanting SKPs that have been pre-labelled with a fluorescence dye, Dil. Expression patterns of Dil and an SKP marker, nestin, was also examined. Results and Conclusion: Accelerated wound healing and enhanced local capillary regeneration could be observed 14 days after skin ablation from both SKPs and collagen sponge co-transplanted and collagen sponge only groups. Subsequent analyses further revealed superior pro-angiogenic effects from the SKP and collagen sponge co-delivered group, which are mainly attributable to in vivo transdifferentation and paracrine signalling of the SKPs.

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TRIM72 is required for effective repair of alveolar epithelial cell wounding

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00172.2014 ◽

2014 ◽

Vol 307 (6) ◽

pp. L449-L459 ◽

Cited By ~ 15

Author(s):

Seong Chul Kim ◽

Thomas Kellett ◽

Shaohua Wang ◽

Miyuki Nishi ◽

Nagaraja Nagre ◽

...

Keyword(s):

Epithelial Cells ◽

Molecular Mechanisms ◽

Striated Muscle ◽

Alveolar Epithelial Cell ◽

Alveolar Epithelial Cells ◽

Lung Cells ◽

Alveolar Epithelial ◽

High Tidal Volume Ventilation

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

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C3 Promotes Clearance of Klebsiella pneumoniae by A549 Epithelial Cells

Infection and Immunity ◽

10.1128/iai.72.3.1767-1774.2004 ◽

2004 ◽

Vol 72 (3) ◽

pp. 1767-1774 ◽

Cited By ~ 26

Author(s):

Beatriz de Astorza ◽

Guadalupe Cortés ◽

Catalina Crespí ◽

Carles Saus ◽

José María Rojo ◽

...

Keyword(s):

Epithelial Cells ◽

Klebsiella Pneumoniae ◽

Alveolar Epithelial Cells ◽

Clinical Isolates ◽

Complement Components ◽

Innate Defense ◽

Alveolar Epithelial

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

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Dome formation in primary cultured monolayers of alveolar epithelial cells

AJP Cell Physiology ◽

10.1152/ajpcell.1982.243.1.c96 ◽

1982 ◽

Vol 243 (1) ◽

pp. C96-C100 ◽

Cited By ~ 86

Author(s):

B. E. Goodman ◽

E. D. Crandall

Keyword(s):

Epithelial Cells ◽

Life Span ◽

Fluid Balance ◽

Alveolar Epithelial Cells ◽

Type Ii ◽

Transport Function ◽

Dome Formation ◽

Alveolar Epithelial ◽

Free Air

We have observed the formation of domes by type II alveolar epithelial cells harvested from rat lungs. The cells were harvested using elastase and grew to confluence in 3-4 days after plating on plastic. Numerous domes were observed in the monolayers 4-18 days after plating, with peak dome density occurring at days 6-9. When trypsin was used instead of elastase as the harvesting enzyme, many fewer domes were formed by the monolayers, with peak dome density observed at day 5 and no domes seen after 8 days. The life span of an individual dome was about 3-4 h. The presence of domes indicates an intact active transport function of the cells in the monolayer, which may represent an important mechanism for the maintenance of fluid-free air spaces and normal alveolar fluid balance in mammalian lungs in vivo.

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