Genetic disruption of protein kinase Cδ reduces endotoxin-induced lung injury

The pathogenesis of acute lung injury and acute respiratory distress syndrome is characterized by sequestration of leukocytes in lung tissue, disruption of capillary integrity, and pulmonary edema. PKCδ plays a critical role in RhoA-mediated endothelial barrier function and inflammatory responses. We used mice with genetic deletion of PKCδ (PKCδ−/−) to assess the role of PKCδ in susceptibility to LPS-induced lung injury and pulmonary edema. Under baseline conditions or in settings of increased capillary hydrostatic pressures, no differences were noted in the filtration coefficients ( kf) or wet-to-dry weight ratios between PKCδ+/+ and PKCδ−/− mice. However, at 24 h after exposure to LPS, the kf values were significantly higher in lungs isolated from PKCδ+/+ than PKCδ−/− mice. In addition, bronchoalveolar lavage fluid obtained from LPS-exposed PKCδ+/+ mice displayed increased protein and cell content compared with LPS-exposed PKCδ−/− mice, but similar changes in inflammatory cytokines were measured. Histology indicated elevated LPS-induced cellularity and inflammation within PKCδ+/+ mouse lung parenchyma relative to PKCδ−/− mouse lungs. Transient overexpression of catalytically inactive PKCδ cDNA in the endothelium significantly attenuated LPS-induced endothelial barrier dysfunction in vitro and increased kf lung values in PKCδ+/+ mice. However, transient overexpression of wild-type PKCδ cDNA in PKCδ−/− mouse lung vasculature did not alter the protective effects of PKCδ deficiency against LPS-induced acute lung injury. We conclude that PKCδ plays a role in the pathological progression of endotoxin-induced lung injury, likely mediated through modulation of inflammatory signaling and pulmonary vascular barrier function.

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Pterostilbene 4′-β-Glucoside Attenuates LPS-Induced Acute Lung Injury via Induction of Heme Oxygenase-1

Oxidative Medicine and Cellular Longevity ◽

10.1155/2018/2747018 ◽

2018 ◽

Vol 2018 ◽

pp. 1-16 ◽

Cited By ~ 6

Author(s):

Jeongmin Park ◽

Yingqing Chen ◽

Min Zheng ◽

Jinhyun Ryu ◽

Gyeong Jae Cho ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Heme Oxygenase ◽

Inflammatory Responses ◽

Critical Role ◽

Mouse Lung ◽

Heme Oxygenase 1 ◽

Ros Production ◽

Protective Effects ◽

Anti Inflammatory

Heme oxygenase-1 (HO-1) can exert anti-inflammatory and antioxidant effects. Acute lung injury (ALI) is associated with increased inflammation and influx of proinflammatory cells and mediators in the airspaces and lung parenchyma. In this study, we demonstrate that pterostilbene 4′-β-glucoside (4-PG), the glycosylated form of the antioxidant pterostilbene (PTER), can protect against lipopolysaccharide- (LPS-) orPseudomonas aeruginosa- (P. aeruginosa-) induced ALI when applied as a pretreatment or therapeutic post-treatment, via the induction of HO-1. To determine whether HO-1 mediates the antioxidant and anti-inflammatory effects of 4-PG, we subjected mice genetically deficient inHmox-1to LPS-induced ALI and evaluated histological changes, HO-1 expression, and proinflammatory cytokine levels in bronchoalveolar lavage (BAL) fluid. 4-PG exhibited protective effects on LPS- orP. aeruginosa-induced ALI by ameliorating pathological changes in lung tissue and decreasing proinflammatory cytokines. In addition, HO-1 expression was significantly increased by 4-PG in cells and in mouse lung tissues. The glycosylated form of pterostilbene (4-PG) was more effective than PTER in inducing HO-1 expression. Genetic deletion ofHmox-1abolished the protective effects of 4-PG against LPS-induced inflammatory responses. Furthermore, we found that 4-PG decreased both intracellular ROS levels and mitochondrial (mt) ROS production in a manner dependent on HO-1. Pharmacological application of the HO-1 reaction product carbon monoxide (CO), but not biliverdin or iron, conferred protection inHmox-1-deficient macrophages. Taken together, these results demonstrate that 4-PG can increase HO-1 expression, which plays a critical role in ameliorating intracellular and mitochondrial ROS production, as well as in downregulating inflammatory responses induced by LPS. Therefore, these findings strongly suggest that HO-1 mediates the antioxidant and anti-inflammatory effects of 4-PG.

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Claudin-4 augments alveolar epithelial barrier function and is induced in acute lung injury

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00043.2009 ◽

2009 ◽

Vol 297 (2) ◽

pp. L219-L227 ◽

Cited By ~ 99

Author(s):

Charlie Wray ◽

Ying Mao ◽

Jue Pan ◽

Anita Chandrasena ◽

Frank Piasta ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Tight Junction ◽

Pulmonary Edema ◽

Barrier Function ◽

Mapk Pathway ◽

Paracellular Transport ◽

Epithelial Barrier ◽

Altered Expression ◽

Alveolar Epithelial

Intact alveolar barrier function is associated with better outcomes in acute lung injury patients; however, the regulation of alveolar epithelial paracellular transport during lung injury has not been extensively investigated. This study was undertaken to determine whether changes in tight junction claudin expression affect alveolar epithelial barrier properties and to determine the mechanisms of altered expression. In anesthetized mice exposed to ventilator-induced lung injury, claudin-4 was specifically induced among tight junction structural proteins. Real-time PCR showed an eightfold increase in claudin-4 expression in the lung injury model. To examine the role of this protein in barrier regulation, claudin-4 function was inhibited with small interfering RNA (siRNA) and a blocking peptide derived from the binding domain of Clostridium perfringens enterotoxin (CPEBD). Inhibition of claudin-4 decreased transepithelial electrical resistance but did not alter macromolecule permeability in primary rat and human epithelial cells. In mice, CPEBD decreased air space fluid clearance >33% and resulted in pulmonary edema during moderate tidal volume ventilation that did not induce edema in control peptide-treated mice. In vitro phorbol ester induced a ninefold increase in claudin-4 expression that was dependent on PKC activation and the JNK MAPK pathway. These data establish that changes in alveolar epithelial claudin expression influence paracellular transport, alveolar fluid clearance rates, and susceptibility to pulmonary edema. We hypothesize that increased claudin-4 expression early in acute lung injury represents a mechanism to limit pulmonary edema and that the regulation of alveolar epithelial claudin expression may be a novel target for acute lung injury therapy.

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Abstract 73: Bone Morphogenetic Protein Activity Modulates Endothelial Barrier Function

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.32.suppl_1.a73 ◽

2012 ◽

Vol 32 (suppl_1) ◽

Author(s):

Thomas Helbing ◽

Elena Ketterer ◽

Bianca Engert ◽

Jennifer Heinke ◽

Sebastian Grundmann ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Barrier Function ◽

Endothelial Permeability ◽

Bmp Signaling ◽

Endothelial Barrier ◽

Endothelial Barrier Function

Introduction: Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome, are associated with high morbidity and mortality in patients. During the progression of ALI, the endothelial cell barrier of the pulmonary vasculature becomes compromised, leading to pulmonary edema, a characteristic feature of ALI. It is well-established that EC barrier dysfunction is initiated by cytoskeletal remodeling, which leads to disruption of cell-cell contacts and formation of paracellular gaps, allowing penetration of protein-rich fluid and inflammatory cells. Bone morphogenetic proteins (BMPs) are important players in endothelial dysfunction and inflammation but their effects on endothelial permeability in ALI have not been investigated until now. Methods and Results: As a first approach to assess the role of BMPs in acute lung injury we analysed BMP4 and BMPER expression in an infectious (LPS) and a non-infectious (bleomycin) mouse models of acute lung injury. In both models BMP4 and BMPER protein expression levels were reduced demonstrated by western blots, suggesting that BMPs are involved in progression ALI. To assess the role of BMPs on vascular leakage, a key feature of ALI, BMP activity in mice was inhibited by i.p. administration of LDN193189, a small molecule that blocks BMP signalling. After 3 days Evans blue dye (EVB) was administered i.v. and dye extravasation into the lungs was quantified as a marker for vascular leakage. Interestingly, LDN193189 significantly increased endothelial permeability compared to control lungs, indicating that BMP signaling is involved in maintenance of endothelial barrier function. To quantify effects of BMP inhibition on endothelial barrier function in vitro, HUVECs were seeded onto transwell filters and were exposed to LDN193189. After 3 days FITC-dextrane was added and passage into the lower chamber was quantified as a marker for endothelial barrier function. Thrombin served as a positive control. As expected from our in vivo experiments inhibition of BMP signaling by LDN193189 enhanced FITC-dextrane passage. To study specific effects of BMPs on endothelial barrier function, two protagonist of the BMP family, BMP2 and BMP4, or BMP modulator BMPER were tested in the transwell assay in vitro. Interestingly BMP4 and BMPER, but not BMP2, reduced FITC-dextrane passage demonstrating that BMP4 and BMPER improved endothelial barrier function. Vice versa, specific knock down of BMP4 or BMPER increased leakage in transwell assays. Im immuncytochemistry silencing of BMPER or BMP4 induced hyperpermeability as a consequence of a pro-inflammatory endothelial phenotype characterised by reduced cell-cell contacts and increased actin stress fiber formation. Additionally, the pro-inflammatory endothelial phenotype was confirmed by real-time revealing increased expression of adhesion molecules ICAM-1 or proinflammatory cytokines such as IL-6 and IL-8 in endothelial cells after BMPER or BMP4 knock down. Confirming these in vitro results BMPER +/- mice exhibit increased extravasation of EVB into the lungs, indicating that partial loss of BMPER impairs endothelial barrier function in vitro and in vivo. Conclusion: We identify BMPER and BMP4 as local regulators of vascular permeability. Both are protective for endothelial barrier function and may open new therapeutic avenues in the treatment of acute lung injury.

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Recipient T lymphocytes modulate the severity of antibody-mediated transfusion-related acute lung injury

Blood ◽

10.1182/blood-2010-05-284570 ◽

2010 ◽

Vol 116 (16) ◽

pp. 3073-3079 ◽

Cited By ~ 38

Author(s):

Yoke Lin Fung ◽

Michael Kim ◽

Arata Tabuchi ◽

Rukhsana Aslam ◽

Edwin R. Speck ◽

...

Keyword(s):

Acute Lung Injury ◽

T Lymphocytes ◽

Lung Injury ◽

Pulmonary Edema ◽

Critical Role ◽

Severe Combined Immunodeficiency ◽

Lung Damage ◽

Moderate Hypothermia ◽

Combined Immunodeficiency ◽

Histocompatibility Complex

Abstract Transfusion-related acute lung injury (TRALI) is a serious complication of transfusion and has been ranked as one of the leading causes of transfusion-related fatalities. Nonetheless, many details of the immunopathogenesis of TRALI, particularly with respect to recipient factors are unknown. We used a murine model of antibody-mediated TRALI in an attempt to understand the role that recipient lymphocytes might play in TRALI reactions. Intravenous injection of an IgG2a antimurine major histocompatibility complex class I antibody (34-1-2s) into BALB/c mice induced moderate hypothermia and pulmonary granulocyte accumulation but no pulmonary edema nor mortality. In contrast, 34-1-2s injections into mice with severe combined immunodeficiency caused severe hypothermia, severe pulmonary edema, and approximately 40% mortality indicating a critical role for T and B lymphocytes in suppressing TRALI reactions. Adoptive transfer of purified CD8+ T lymphocytes or CD4+ T cells but not CD19+ B cells into the severe combined immunodeficiency mice alleviated the antibody-induced hypothermia, lung damage, and mortality, suggesting that T lymphocytes were responsible for the protective effect. Taken together, these results suggest that recipient T lymphocytes play a significant role in suppressing antibody-mediated TRALI reactions. They identify a potentially new recipient mechanism that controls the severity of TRALI reactions.

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Src protein tyrosine kinase family and acute inflammatory responses

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00261.2005 ◽

2006 ◽

Vol 291 (2) ◽

pp. L129-L141 ◽

Cited By ~ 111

Author(s):

Daisuke Okutani ◽

Monika Lodyga ◽

Bing Han ◽

Mingyao Liu

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Tyrosine Kinase ◽

Reperfusion Injury ◽

Protein Tyrosine Kinase ◽

Inflammatory Responses ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Critical Role ◽

Protein Tyrosine

Acute inflammatory responses are one of the major underlying mechanisms for tissue damage of multiple diseases, such as ischemia-reperfusion injury, sepsis, and acute lung injury. By use of cellular and molecular approaches and transgenic animals, Src protein tyrosine kinase (PTK) family members have been identified to be essential for the recruitment and activation of monocytes, macrophages, neutrophils, and other immune cells. Src PTKs also play a critical role in the regulation of vascular permeability and inflammatory responses in tissue cells. Importantly, animal studies have demonstrated that small chemical inhibitors for Src PTKs attenuate tissue injury and improve survival from a variety of pathological conditions related to acute inflammatory responses. Further investigation may lead to the clinical application of these inhibitors as drugs for ischemia-reperfusion injury (such as stroke and myocardial infarction), sepsis, acute lung injury, and multiple organ dysfunction syndrome.

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The Disruption of the Endothelial Barrier Contributes to Acute Lung Injury Induced by Coxsackievirus A2 Infection in Mice

International Journal of Molecular Sciences ◽

10.3390/ijms22189895 ◽

2021 ◽

Vol 22 (18) ◽

pp. 9895

Author(s):

Wangquan Ji ◽

Qiang Hu ◽

Mengdi Zhang ◽

Chuwen Zhang ◽

Chen Chen ◽

...

Keyword(s):

Endothelial Cells ◽

Acute Lung Injury ◽

Lung Injury ◽

Pulmonary Edema ◽

Foot And Mouth Disease ◽

Epidemiological Studies ◽

Mapk Signaling ◽

Lung Damage ◽

Mitogen Activated Protein Kinase ◽

Endothelial Barrier

Sporadic occurrences and outbreaks of hand, foot, and mouth disease (HFMD) caused by Coxsackievirus A2 (CVA2) have frequently reported worldwide recently, which pose a great challenge to public health. Epidemiological studies have suggested that the main cause of death in critical patients is pulmonary edema. However, the pathogenesis of this underlying comorbidity remains unclear. In this study, we utilized the 5-day-old BALB/c mouse model of lethal CVA2 infection to evaluate lung damage. We found that the permeability of lung microvascular was significantly increased after CVA2 infection. We also observed the direct infection and apoptosis of lung endothelial cells as well as the destruction of tight junctions between endothelial cells. CVA2 infection led to the degradation of tight junction proteins (e.g., ZO-1, claudin-5, and occludin). The gene transcription levels of von Willebrand factor (vWF), endothelin (ET), thrombomodulin (THBD), granular membrane protein 140 (GMP140), and intercellular cell adhesion molecule-1 (ICAM-1) related to endothelial dysfunction were all significantly increased. Additionally, CVA2 infection induced the increased expression of inflammatory cytokines (IL-6, IL-1β, and MCP-1) and the activation of p38 mitogen-activated protein kinase (MAPK). In conclusion, the disruption of the endothelial barrier contributes to acute lung injury induced by CVA2 infection; targeting p38-MAPK signaling may provide a therapeutic approach for pulmonary edema in critical infections of HFMD.

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Unfractionated heparin ameliorates pulmonary microvascular endothelial barrier dysfunction via microtubule stabilization in acute lung injury

Respiratory Research ◽

10.1186/s12931-018-0925-6 ◽

2018 ◽

Vol 19 (1) ◽

Cited By ~ 7

Author(s):

Shengtian Mu ◽

Yina Liu ◽

Jing Jiang ◽

Renyu Ding ◽

Xu Li ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Unfractionated Heparin ◽

Endothelial Barrier ◽

Barrier Dysfunction ◽

Microtubule Stabilization ◽

Endothelial Barrier Dysfunction ◽

Microvascular Endothelial

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Temporal changes in pulmonary expression of key procoagulant molecules in rabbits with endotoxin-induced acute lung injury: elevated expression levels of protease-activated receptors

Thrombosis and Haemostasis ◽

10.1160/th04-03-0160 ◽

2004 ◽

Vol 92 (11) ◽

pp. 966-979 ◽

Cited By ~ 27

Author(s):

Subrina Jesmin ◽

Naoyuki Matsuda ◽

Ichiro Sakuma ◽

Shigeaki Kobayashi ◽

Fumika Sakuraya ◽

...

Keyword(s):

Acute Lung Injury ◽

Lung Injury ◽

Inflammatory Responses ◽

Tissue Injury ◽

Critical Role ◽

Control Level ◽

Temporal Changes ◽

Expression Levels ◽

Time Courses ◽

Pai 1

SummaryRecently a new concept has emerged implicating thrombin signaling as the “bridge” that connects tissue damage to hemostatic and inflammatory responses. In view of this concept, we hypothesized that induction of protease-activated receptor (PAR) expression may play a critical role in endotoxin-induced tissue injury through the cellular actions of thrombin. Thus, in this study, temporal changes in expression of key precoagulant molecules, including PARs, in lungs from rabbits rendered endotoxemic by 100 μg/kg lipopolysaccharide (LPS) were examined with measurements of variables reflecting acute lung injury (ALI). ALI induction by LPS was confirmed by blood gas derangement, lung vascular hyperpermeability, and histopathological changes, and was characterized by the deposition of fibrin in the alveolar spaces, bronchioles and vessels. Plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) were highly expressed in lungs after LPS injection. While the peaks in levels of PAI-1 and TF were comparable (12∼13-fold from control), their expression time-courses were different: PAI-1 exhibited a bell-shaped expression pattern and peak at 6 h, whereas TF level reached maximum at 10 h. Of note, LPS induced a rapid and significant increase in levels of PAR-1 compared to control, with a peak level at 1 h (3.3-fold). Although declining thereafter, it remained significantly higher than the control level throughout the study period. Expressions of PAR-2, -3, and -4 were also increased by LPS with different time courses from PAR-1 expression. Immunofluorescence staining for PAR-1 were localized in blood vessels, bronchial epithelium, and alveolar pneumocytes after LPS. These results suggest that the increased expression levels of PARs, in addition to PAI-1 and TF, may, in part, underlie the development of ALI occurring during endotoxemia.

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