scholarly journals The relative balance of GM-CSF and TGF-β1 regulates lung epithelial barrier function

2015 ◽  
Vol 308 (12) ◽  
pp. L1212-L1223 ◽  
Author(s):  
Christian E. Overgaard ◽  
Barbara Schlingmann ◽  
StevenClaude Dorsainvil White ◽  
Christina Ward ◽  
Xian Fan ◽  
...  
Keyword(s):  
Barrier Function ◽  
Transforming Growth Factor ◽  
Cultured Cells ◽  
Lung Epithelial Cells ◽  
Epithelial Barrier ◽  
Barrier Dysfunction ◽  
Epithelial Barrier Function ◽  
Gm Csf ◽  
Lung Epithelial ◽  
Tgf Β1

Lung barrier dysfunction is a cardinal feature of the acute respiratory distress syndrome (ARDS). Alcohol abuse, which increases the risk of ARDS two- to fourfold, induces transforming growth factor (TGF)-β1, which increases epithelial permeability and impairs granulocyte/macrophage colony-stimulating factor (GM-CSF)-dependent barrier integrity in experimental models. We hypothesized that the relative balance of GM-CSF and TGF-β1 signaling regulates lung epithelial barrier function. GM-CSF and TGF-β1 were tested separately and simultaneously for their effects on lung epithelial cell barrier function in vitro. TGF-β1 alone caused an ∼25% decrease in transepithelial resistance (TER), increased paracellular flux, and was associated with projections perpendicular to tight junctions (“spikes”) containing claudin-18 that colocalized with F-actin. In contrast, GM-CSF treatment induced an ∼20% increase in TER, decreased paracellular flux, and showed decreased colocalization of spike-associated claudin-18 with F-actin. When simultaneously administered to lung epithelial cells, GM-CSF antagonized the effects of TGF-β1 on epithelial barrier function in cultured cells. Given this, GM-CSF and TGF-β1 levels were measured in bronchoalveolar lavage (BAL) fluid from patients with ventilator-associated pneumonia and correlated with markers for pulmonary edema and patient outcome. In patient BAL fluid, protein markers of lung barrier dysfunction, serum α2-macroglobulin, and IgM levels were increased at lower ratios of GM-CSF/TGF-β1. Critically, patients who survived had significantly higher GM-CSF/TGF-β1 ratios than nonsurviving patients. This study provides experimental and clinical evidence that the relative balance between GM-CSF and TGF-β1 signaling is a key regulator of lung epithelial barrier function. The GM-CSF/TGF-β1 ratio in BAL fluid may provide a concentration-independent biomarker that can predict patient outcomes in ARDS.

scholarly journals Transforming Growth Factor β1 Ameliorates Intestinal Epithelial Barrier Disruption by Cryptosporidium parvum In Vitro in the Absence of Mucosal T Lymphocytes

2000 ◽  
Vol 68 (10) ◽  
pp. 5635-5644 ◽  
Author(s):  
James K. Roche ◽  
Clovis A. P. Martins ◽  
Rosana Cosme ◽  
Ronald Fayer ◽  
Richard L. Guerrant
Keyword(s):  
Epithelial Cell ◽  
Barrier Function ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Epithelial Barrier Function ◽  
Epithelial Monolayers ◽  
Tgf Β1

ABSTRACT Exposure to oocysts of the protozoan Cryptosporidium parvum causes intestinal epithelial cell dysfunction in vivo and in vitro, but effective means by which mucosal injury might be prevented remain unclear. We examined the ability of transforming growth factor β1 (TGF-β1)—a cytokine synthesized and released by cells in the intestine—to preserve the barrier function of human colonic epithelia when challenged with C. parvum oocysts and then studied the mechanisms involved. Epithelial barrier function was monitored electrophysiologically, receptors for TGF-β1 were localized by confocal microscopy, and TGF-β1-induced protein kinase C activation was detected intracellularly by translocation of its α isozyme. TGF-β1 alone enhanced intestinal epithelial barrier function, while exposure to C. parvum oocysts (≥105/monolayer) markedly reduced barrier function to ≤40% of that of the control. When epithelial monolayers were pretreated with TGF-β1 at 5.0 ng/ml, the barrier-disrupting effect ofC. parvum oocysts was almost completely abrogated for 96 h. Further investigation showed that (i) the RI and RII receptors for TGF-β1 were present on 55 and 65% of human epithelial cell line cells, respectively, over a 1-log-unit range of receptor protein expression, as shown by flow cytometry and confirmed by confocal microscopy; (ii) only basolateral and not apical TGF-β1 exposure of the polarized epithelial monolayer resulted in a protective effect; and (iii) TGF-β1 had no direct effect on the organism in reducing its tissue-disruptive effects. In exploring mechanisms to account for the barrier-preserving effects of TGF-β1 on epithelium, we found that the protein kinase C pathway was activated, as shown by translocation of its 80-kDa α isozyme within 30 s of epithelial exposure to TGF-β1; the permeability of epithelial monolayers to passage of macromolecules was reduced by 42% with TGF-β1, even in the face of active protozoal infection; and epithelial cell necrosis monitored by lactate dehydrogenase release was decreased by 50% 70 h after oocyst exposure. Changes in epithelial function, initiated through an established set of surface receptors, likely accounts for the remarkable barrier-sparing effect of nanogram-per-milliliter concentrations of TGF-β1 when human colonic epithelium is exposed to an important human pathogen, C. parvum.

Microtubule dynamics and Rac-1 signaling independently regulate barrier function in lung epithelial cells

2007 ◽  
Vol 293 (5) ◽  
pp. L1321-L1331 ◽  
Author(s):  
Magdalena J. Lorenowicz ◽  
Mar Fernandez-Borja ◽  
Anne-Marieke D. van Stalborch ◽  
Marian A. J. A. van Sterkenburg ◽  
Pieter S. Hiemstra ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Barrier Function ◽  
Lung Epithelial Cells ◽  
Cell Junctions ◽  
Epithelial Barrier ◽  
Cell Contact ◽  
Epithelial Barrier Function ◽  
Lung Epithelial ◽  
Cell Cell

Cadherin-mediated cell-cell adhesion controls the morphology and function of epithelial cells and is a critical component of the pathology of chronic inflammatory disorders. Dynamic interactions between cadherins and the actin cytoskeleton are required for stable cell-cell contact. Besides actin, microtubules also target intercellular, cadherin-based junctions and contribute to their formation and stability. Here, we studied the role of microtubules in conjunction with Rho-like GTPases in the regulation of lung epithelial barrier function using real-time monitoring of transepithelial electrical resistance. Unexpectedly, we found that disruption of microtubules promotes epithelial cell-cell adhesion. This increase in epithelial barrier function is accompanied by the accumulation of β-catenin at cell-cell junctions, as detected by immunofluorescence. Moreover, we found that the increase in cell-cell contact, induced by microtubule depolymerization, requires signaling through a RhoA/Rho kinase pathway. The Rac-1 GTPase counteracts this pathway, because inhibition of Rac-1 signaling rapidly promotes epithelial barrier function, in a microtubule- and RhoA-independent fashion. Together, our data suggest that microtubule-RhoA-mediated signaling and Rac-1 control lung epithelial integrity through counteracting independent pathways.

scholarly journals PGC-1α mediates a metabolic host defense response in human airway epithelium during rhinovirus infections

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aubrey N. Michi ◽  
Bryan G. Yipp ◽  
Antoine Dufour ◽  
Fernando Lopes ◽  
David Proud
Keyword(s):  
Host Defense ◽  
Barrier Function ◽  
Bacterial Infections ◽  
Molecular Mechanisms ◽  
Cellular Damage ◽  
Epithelial Barrier ◽  
Airway Epithelial ◽  
Barrier Dysfunction ◽  
Epithelial Barrier Function ◽  
Epithelial Damage

AbstractHuman rhinoviruses (HRV) are common cold viruses associated with exacerbations of lower airways diseases. Although viral induced epithelial damage mediates inflammation, the molecular mechanisms responsible for airway epithelial damage and dysfunction remain undefined. Using experimental HRV infection studies in highly differentiated human bronchial epithelial cells grown at air-liquid interface (ALI), we examine the links between viral host defense, cellular metabolism, and epithelial barrier function. We observe that early HRV-C15 infection induces a transitory barrier-protective metabolic state characterized by glycolysis that ultimately becomes exhausted as the infection progresses and leads to cellular damage. Pharmacological promotion of glycolysis induces ROS-dependent upregulation of the mitochondrial metabolic regulator, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), thereby restoring epithelial barrier function, improving viral defense, and attenuating disease pathology. Therefore, PGC-1α regulates a metabolic pathway essential to host defense that can be therapeutically targeted to rescue airway epithelial barrier dysfunction and potentially prevent severe respiratory complications or secondary bacterial infections.

scholarly journals Chymase-mediated intestinal epithelial permeability is regulated by a protease-activating receptor/matrix metalloproteinase-2-dependent mechanism

2013 ◽  
Vol 304 (5) ◽  
pp. G479-G489 ◽  
Author(s):  
Katherine R. Groschwitz ◽  
David Wu ◽  
Heather Osterfeld ◽  
Richard Ahrens ◽  
Simon P. Hogan
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Barrier Function ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Barrier Dysfunction ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Epithelial Barrier Dysfunction

Mast cells regulate intestinal barrier function during disease and homeostasis. Secretion of the mast cell-specific serine protease chymase regulates homeostasis. In the present study, we employ in vitro model systems to delineate the molecular pathways involved in chymase-mediated intestinal epithelial barrier dysfunction. Chymase stimulation of intestinal epithelial (Caco-2 BBe) cell monolayers induced a significant reduction in transepithelial resistance, indicating decreased intestinal epithelial barrier function. The chymase-induced intestinal epithelial barrier dysfunction was characterized by chymase-induced protease-activated receptor (PAR)-2 activation and matrix metalloproteinase (MMP)-2 expression and activation. Consistent with this observation, in vitro analysis revealed chymase-induced PAR-2 activation and increased MAPK activity and MMP-2 expression. Pharmacological and small interfering RNA-mediated antagonism of PAR-2 and MMP-2 significantly attenuated chymase-stimulated barrier dysfunction. Additionally, the chymase/MMP-2-mediated intestinal epithelial dysfunction was associated with a significant reduction in the tight junction protein claudin-5, which was partially restored by MMP-2 inhibition. Finally, incubation of Caco-2 BBe cells with chymase-sufficient, but not chymase-deficient, bone marrow-derived mast cells decreased barrier function, which was attenuated by the chymase inhibitor chymostatin. Collectively, these results suggest that mast cell/chymase-mediated intestinal epithelial barrier function is mediated by PAR-2/MMP-2-dependent pathways.

Murine filaggrin-2 is involved in epithelial barrier function and down-regulated in metabolically induced skin barrier dysfunction

2012 ◽  
Vol 21 (4) ◽  
pp. 271-276 ◽  
Author(s):  
Britta Hansmann ◽  
Kerstin Ahrens ◽  
Zhihong Wu ◽  
Ehrhardt Proksch ◽  
Ulf Meyer-Hoffert ◽  
...  
Keyword(s):  
Barrier Function ◽  
Skin Barrier ◽  
Epithelial Barrier ◽  
Barrier Dysfunction ◽  
Epithelial Barrier Function

scholarly journals The role of secreted Hsp90α in HDM-induced asthmatic airway epithelial barrier dysfunction

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Cuiping Ye ◽  
Chaowen Huang ◽  
Mengchen Zou ◽  
Yahui Hu ◽  
Lishan Luo ◽  
...  
Keyword(s):  
Barrier Function ◽  
Epithelial Barrier ◽  
Airway Epithelial ◽  
Barrier Dysfunction ◽  
Epithelial Barrier Function ◽  
Asthmatic Airway ◽  
Epithelial Barrier Dysfunction

Abstract Background The dysfunction of airway epithelial barrier is closely related to the pathogenesis of asthma. Secreted Hsp90α participates in inflammation and Hsp90 inhibitor protects endothelial dysfunction. In the current study, we aimed to explore the role of secreted Hsp90α in asthmatic airway epithelial barrier function. Methods Male BALB/c mice were sensitized and challenged with HDM to generate asthma model. The 16HBE and Hsp90α-knockdown cells were cultured and treated according to the experiment requirements. Transepithelial Electric Resistance (TEER) and permeability of epithelial layer in vitro, distribution and expression of junction proteins both in vivo and in vitro were used to evaluate the epithelial barrier function. Western Blot was used to evaluate the expression of junction proteins and phosphorylated AKT in cells and lung tissues while ELISA were used to evaluate the Hsp90α expression and cytokines release in the lung homogenate. Results HDM resulted in a dysfunction of airway epithelial barrier both in vivo and in vitro, paralleled with the increased expression and release of Hsp90α. All of which were rescued in Hsp90α-knockdown cells or co-administration of 1G6-D7. Furthermore, either 1G6-D7 or PI3K inhibitor LY294002 suppressed the significant phosphorylation of AKT, which caused by secreted and recombinant Hsp90α, resulting in the restoration of epithelial barrier function. Conclusions Secreted Hsp90α medicates HDM-induced asthmatic airway epithelial barrier dysfunction via PI3K/AKT pathway, indicating that anti-secreted Hsp90α therapy might be a potential treatment to asthma in future.

scholarly journals Hypoxia-inducible factor hydroxylase inhibition enhances the protective effects of cyclosporine in colitis

2019 ◽  
Vol 317 (2) ◽  
pp. G90-G97 ◽  
Author(s):  
Doug N. Halligan ◽  
Mohammed N. Khan ◽  
Eric Brown ◽  
Catherine R. Rowan ◽  
Ivan S. Coulter ◽  
...  
Keyword(s):  
Inflammatory Bowel Disease ◽  
Immune System ◽  
Protective Effect ◽  
Barrier Function ◽  
Epithelial Barrier ◽  
Protective Effects ◽  
Barrier Dysfunction ◽  
Epithelial Barrier Function ◽  
Inflammatory Bowel ◽  
Anti Inflammatory

Inflammatory bowel disease (IBD) is characterized by epithelial barrier dysfunction with resultant inflammation as the mucosal immune system becomes exposed to luminal antigens. The hydroxylase inhibitor dimethyloxalylglycine (DMOG) reduces symptoms in experimental colitis through the upregulation of genes promoting barrier function and inhibition of epithelial cell apoptosis. The immunosuppressive drug cyclosporine reduces inflammation associated with IBD via suppression of immune cell activation. Given the distinct barrier protective effect of DMOG and the anti-inflammatory properties of cyclosporine, we hypothesized that combining these drugs may provide an enhanced protective effect by targeting both barrier dysfunction and inflammation simultaneously. We used the dextran sulfate sodium model of colitis in C57BL/6 mice to determine the combinatorial efficacy of cyclosporine and DMOG. While cyclosporine and DMOG ameliorated disease progression, in combination they had an additive protective effect that surpassed the level of protection afforded by either drug alone. The ability of DMOG to augment the anti-inflammatory effects of cyclosporine was largely due to preservation of barrier function and at least in part due to zonula occludens-1 regulation. We propose that combining the barrier protective effects of a hydroxylase inhibitor with the anti-inflammatory effects of cyclosporine provides added therapeutic benefit in colitis. NEW & NOTEWORTHY Inflammatory bowel disease is the result of decreased intestinal epithelial barrier function leading to exposure of the mucosal immune system to luminal antigens causing inflammation, which in turn further decreases epithelial barrier function. We demonstrate for the first time that strengthening the epithelial barrier with a hydroxylase inhibitor in combination with the administration of the immunosuppressive cyclosporine provides additive therapeutic advantage in a murine model of colitis

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