scholarly journals Mechanical Ventilation Induces Desensitization of Lung Axl Tyrosine Kinase Receptors

2018 ◽  
Vol 129 (1) ◽  
pp. 143-153 ◽  
Author(s):  
Gail Otulakowski ◽  
Doreen Engelberts ◽  
Martin Post ◽  
Claire Masterson ◽  
Brian P. Kavanagh
Keyword(s):  
Lung Injury ◽  
Tidal Volume ◽  
Calcium Ionophore ◽  
Cyclic Stretch ◽  
High Tidal Volume ◽  
Cytokine Signaling ◽  
Lung Physiology ◽  
Lung Endothelial Cells

Abstract Background Lower tidal volumes are increasingly used in acute respiratory distress syndrome, but mortality has changed little in the last 20 yr. Therefore, in addition to ventilator settings, it is important to target molecular mediators of injury. Sepsis and other inflammatory states increase circulating concentrations of Gas6, a ligand for the antiinflammatory receptor Axl, and of a soluble decoy form of Axl. We investigated the effects of lung stretch on Axl signaling. Methods We used a mouse model of early injury from high tidal volume and assessed the effects of inhibiting Axl on in vivo lung injury (using an antagonist R428, n = 4/group). We further determined the effects of stretch on Axl activation using in vitro lung endothelial cells. Results High tidal volume caused mild injury (compliance decreased 6%) as intended, and shedding of the Axl receptor (soluble Axl in bronchoalveolar fluid increased 77%). The Axl antagonist R428 blocked the principal downstream Axl target (suppressor of cytokine signaling 3 [SOCS3]) but did not worsen lung physiology or inflammation. Cyclic stretch in vitro caused Axl to become insensitive to activation by its agonist, Gas6. Finally, in vitro Axl responses were rescued by blocking stretch-activated calcium channels (using guanidinium chloride [GdCl3]), and the calcium ionophore ionomycin replicated the effect of stretch. Conclusions These data suggest that lung endothelial cell overdistention activates ion channels, and the resultant influx of Ca2+ inactivates Axl. Downstream inactivation of Axl by stretch was not anticipated; preventing this would be required to exploit Axl receptors in reducing lung injury.

scholarly journals The Elk1/MMP-9 axis regulates E-cadherin and occludin in ventilator-induced lung injury

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhao Tao ◽  
Yan Jie ◽  
Zhang Mingru ◽  
Gu Changping ◽  
Yang Fan ◽  
...  
Keyword(s):  
Lung Injury ◽  
Tidal Volume ◽  
Tight Junctions ◽  
Cyclic Stretch ◽  
High Tidal Volume ◽  
Ventilator Induced Lung Injury ◽  
Cell Counts ◽  
E Cadherin

Abstract Background Ventilator-induced lung injury (VILI) is a common complication in the treatment of respiratory diseases with high morbidity and mortality. ETS-domain containing protein (Elk1) and Matrix metalloproteinase (MMP) 9 are involved in VILI, but the roles have not been fully elucidated. This study examined the mechanisms of the activation of MMP-9 and Elk1 regulating barrier function in VILI in vitro and in vivo. Methods For the in vitro study, Mouse lung epithelial cells (MLE-12) were pre-treated with Elk1 siRNA or MMP-9 siRNA for 48 h prior to cyclic stretch at 20% for 4 h. For the in vivo study, C57BL/6 mice were pre-treated with Elk1 siRNA or MMP-9 siRNA for 72 h prior to 4 h of mechanical ventilation. The expressions of Elk1, MMP-9, Tissue inhibitor of metalloproteinase 1 (TIMP-1), E-cadherin, and occludin were measured by Western blotting. The intracellular distribution of E-cadherin and occludin was shown by immunofluorescence. The degree of pulmonary edema and lung injury were evaluated by Hematoxylin–eosin (HE) staining, lung injury scores, Wet/Dry (W/D) weight ratio, total cell counts, and Evans blue dye. Results 20% cyclic stretch and high tidal volume increases the expressions of Elk1, MMP-9, and TIMP-1, increases the ratio of MMP-9/TIMP-1, decreases the E-cadherin and occludin level. Elk1 siRNA or MMP-9 siRNA reverses the degradations of E-cadherin, occludin, and the ratio of MMP-9/TIMP-1 caused by cyclic stretch. Elk1 siRNA decreases the MMP-9 level with or not 20% cyclic stretch and high tidal volume. Conclusions The results demonstrate mechanical stretch damages the tight junctions and aggravates the permeability in VILI, Elk1 plays an important role in affecting the tight junctions and permeability by regulating the balance of MMP-9 and TIMP-1, thus indicating the therapeutic potential of Elk1 to treat VILI.

scholarly journals Lidocaine Alleviates Sepsis-Induced Acute Lung Injury in Mice by Suppressing Tissue Factor and Matrix Metalloproteinase-2/9

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Binbin Zheng ◽  
Hongbo Yang ◽  
Jianan Zhang ◽  
Xueli Wang ◽  
Hao Sun ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Matrix Metalloproteinase ◽  
Gelatin Zymography ◽  
Neutrophil Infiltration ◽  
Negative Regulator ◽  
Matrix Metalloproteinase 2 ◽  
Cytokine Signaling

Acute lung injury (ALI) is one of the fatal symptoms of sepsis. However, there were no effective clinical treatments. TF accumulation-induced fibrin deposit formations and coagulation abnormalities in pulmonary vessels contribute to the lethality of ALI. Suppressor of cytokine signaling 3 (SOCS3) acts as an endogenous negative regulator of the TLR4/TF pathway. We hypothesized that inducing SOCS3 expression using lidocaine to suppress the TLR4/TF pathway may alleviate ALI. Hematoxylin and eosin (H&E), B-mode ultrasound, and flow cytometry were used to measure the pathological damage of mice. Gelatin zymography was used to measure matrix metalloproteinase-2/9 (MMP-2/9) activities. Western blot was used to assay the expression of protein levels. Here, we show that lidocaine could increase the survival rate of ALI mice and ameliorate the lung injury of ALI mice including reducing the edema, neutrophil infiltration, and pulmonary thrombosis formation and increasing blood flow velocity. Moreover, in vitro and in vivo, lidocaine could increase the expression of p-AMPK and SOCS3 and subsequently decrease the expression of p-ASK1, p-p38, TF, and the activity of MMP-2/9. Taken together, our study demonstrated that lidocaine could inhibit the TLR4/ASK1/TF pathway to alleviate ALI via activating AMPK-SOCS3 axis.

scholarly journals Mechanosensitive cation channel Piezo1 contributes to ventilator-induced lung injury by activating RhoA/ROCK1 in rats

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yang Zhang ◽  
Lulu Jiang ◽  
Tianfeng Huang ◽  
Dahao Lu ◽  
Yue Song ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Tidal Volume ◽  
Cyclic Stretch ◽  
High Tidal Volume ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sprague Dawley ◽  
Ventilator Induced Lung Injury ◽  
Enhanced Expression ◽  
Underlying Mechanisms

Abstract Background Mechanical ventilation can induce or aggravate lung injury, which is termed ventilator-induced lung injury (VILI). Piezo1 is a key element of the mechanotransduction process and can transduce mechanical signals into biological signals by mediating Ca2+ influx, which in turn regulates cytoskeletal remodeling and stress alterations. We hypothesized that it plays an important role in the occurrence of VILI, and investigated the underlying mechanisms. Methods High tidal volume mechanical ventilation and high magnitude cyclic stretch were performed on Sprague–Dawley rats, and A549 and human pulmonary microvascular endothelial cells, respectively, to establish VILI models. Immunohistochemical staining, flow cytometry, histological examination, enzyme-linked immunosorbent assay, western blotting, quantitative real-time polymerase chain reaction and survival curves were used to assess the effect of Piezo1 on induction of lung injury, as well as the signaling pathways involved. Results We observed that Piezo1 expression increased in the lungs after high tidal volume mechanical ventilation and in cyclic stretch-treated cells. Mechanistically, we observed the enhanced expression of RhoA/ROCK1 in both cyclic stretch and Yoda1-treated cells, while the deficiency or inhibition of Piezo1 dramatically antagonized RhoA/ROCK1 expression. Furthermore, blockade of RhoA/ROCK1 signaling using an inhibitor did not affect Piezo1 expression. GSMTx4 was used to inhibit Piezo1, which alleviated VILI-induced pathologic changes, water content and protein leakage in the lungs, and the induction of systemic inflammatory mediators, and improved the 7-day mortality rate in the model rats. Conclusions These findings indicate that Piezo1 affects the development and progression of VILI through promotion of RhoA/ROCK1 signaling.

Mechanisms of early pulmonary neutrophil sequestration in ventilator-induced lung injury in mice

2004 ◽  
Vol 287 (5) ◽  
pp. L902-L910 ◽  
Author(s):  
Sharmila Choudhury ◽  
Michael R. Wilson ◽  
Michael E. Goddard ◽  
Kieran P. O'Dea ◽  
Masao Takata
Keyword(s):  
Lung Injury ◽  
Tidal Volume ◽  
Molecular Mechanisms ◽  
Control Ventilation ◽  
Volume Control ◽  
Neutrophil Sequestration ◽  
Ventilator Induced Lung Injury ◽  
Volume Control Ventilation

Polymorphonuclear leukocytes (PMN) play an important role in ventilator-induced lung injury (VILI), but the mechanisms of pulmonary PMN recruitment, particularly early intravascular PMN sequestration during VILI, have not been elucidated. We investigated the physiological and molecular mechanisms of pulmonary PMN sequestration in an in vivo mouse model of VILI. Anesthetized C57/BL6 mice were ventilated for 1 h with high tidal volume (injurious ventilation), low tidal volume and high positive end-expiratory pressure (protective ventilation), or normal tidal volume (control ventilation). Pulmonary PMN sequestration analyzed by flow cytometry of lung cell suspensions was substantially enhanced in injurious ventilation compared with protective and control ventilation, preceding development of physiological signs of lung injury. Anesthetized, spontaneously breathing mice with continuous positive airway pressure demonstrated that raised alveolar pressure alone does not induce PMN entrapment. In vitro leukocyte deformability assay indicated stiffening of circulating leukocytes in injurious ventilation compared with control ventilation. PMN sequestration in injurious ventilation was markedly inhibited by administration of anti-L-selectin antibody, but not by anti-CD18 antibody. These results suggest that mechanical ventilatory stress initiates pulmonary PMN sequestration early in the course of VILI, and this phenomenon is associated with stretch-induced inflammatory events leading to PMN stiffening and mediated by L-selectin-dependent but CD18-independent mechanisms.

scholarly journals Rap1 mediates protective effects of iloprost against ventilator-induced lung injury

2009 ◽  
Vol 107 (6) ◽  
pp. 1900-1910 ◽  
Author(s):  
Anna A. Birukova ◽  
Panfeng Fu ◽  
Junjie Xing ◽  
Konstantin G. Birukov
Keyword(s):  
Lung Injury ◽  
Bronchoalveolar Lavage ◽  
Tidal Volume ◽  
Evans Blue ◽  
High Tidal Volume ◽  
Protective Effects ◽  
Ventilator Induced Lung Injury ◽  
High Tidal Volume Ventilation ◽  
Volume Ventilation

Prostaglandin I2 (PGI2) has been shown to attenuate vascular constriction, hyperpermeability, inflammation, and acute lung injury. However, molecular mechanisms of PGI2 protective effects on pulmonary endothelial cells (EC) are not well understood. We tested a role of cAMP-activated Epac-Rap1 pathway in the barrier protective effects of PGI2 analog iloprost in the murine model of ventilator-induced lung injury. Mice were treated with iloprost (2 μg/kg) after onset of high tidal volume ventilation (30 ml/kg, 4 h). Bronchoalveolar lavage, histological analysis, and measurements of Evans blue accumulation were performed. In vitro, microvascular EC barrier function was assessed by morphological analysis of agonist-induced gap formation and monitoring of Rho pathway activation and EC permeability. Iloprost reduced bronchoalveolar lavage protein content, neutrophil accumulation, capillary filtration coefficient, and Evans blue albumin extravasation caused by high tidal volume ventilation. Small-interfering RNA-based Rap1 knockdown inhibited protective effects of iloprost. In vitro, iloprost increased barrier properties of lung microvascular endothelium and alleviated thrombin-induced EC barrier disruption. In line with in vivo results, Rap1 depletion attenuated protective effects of iloprost in the thrombin model of EC permeability. These data describe for the first time protective effects for Rap1-dependent signaling against ventilator-induced lung injury and pulmonary endothelial barrier dysfunction.

scholarly journals Mechanosensitive Cation Channel Piezo1 Contributes To Ventilator-Induced Lung Injury By Activating RhoA/ROCK1 In Rats

2021 ◽  
Author(s):  
Yang Zhang ◽  
Lulu Jiang ◽  
Tianfeng Huang ◽  
Dahao Lu ◽  
Yue Song ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Tidal Volume ◽  
Cyclic Stretch ◽  
High Tidal Volume ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sprague Dawley ◽  
Reverse Transcription Pcr ◽  
Ventilator Induced Lung Injury ◽  
Underlying Mechanisms

Abstract Background: Mechanical ventilation can induce or aggravate lung injury, which is termed ventilator‑induced lung injury. Piezo1 is a key element of the mechanotransduction process and can transduce mechanical signals into biological signals by mediating Ca2+ influx, which in turn regulates cytoskeletal remodeling and stress alterations. We hypothesized that it plays an important role in the occurrence of ventilator‑induced lung injury, and we investigated the underlying mechanisms. Methods: High tidal volume mechanical ventilation and high magnitude cyclic stretch were performed on Sprague Dawley rats, and A549 and human pulmonary microvascular endothelial cells, respectively, to establish ventilator‑induced lung injury models. Immunohistochemical staining, flow cytometry, histological examination, enzyme-linked immunosorbent assay, western blotting, quantitative real-time reverse transcription-PCR and survival curves were used to assess the effect of Piezo1 on induction of lung injury, as well as the signaling pathways involved.Results: We observed that Piezo1 expression increased in the lungs after high tidal volume mechanical ventilation and in cyclic stretch-treated cells. Mechanistically, we observed the enhanced expression of RhoA/ROCK1 in both cyclic stretch and Yoda1-treated cells, while the deficiency or inhibition of Piezo1 dramatically antagonized RhoA/ROCK1 expression. Furthermore, blockade of RhoA/ROCK1 signaling using an inhibitor did not affect Piezo1 expression. GSMTx4 was used to inhibit Piezo1, which alleviated ventilator‑induced lung injury-induced pathologic changes, water content and protein leakage in the lungs, and the induction of systemic inflammatory mediators, and improved the 7-day mortality rate in the model rats. Conclusions: These findings indicate that Piezo1 affects the development and progression of ventilator‑induced lung injury through promotion of RhoA/ROCK1 signaling.

scholarly journals PIEZO1 Ion Channel Mediates Ionizing Radiation-Induced Pulmonary Endothelial Cell Ferroptosis via Ca2+/Calpain/VE-Cadherin Signaling

2021 ◽  
Vol 8 ◽  
Author(s):  
Xue-Wei Guo ◽  
Hao Zhang ◽  
Jia-Qi Huang ◽  
Si-Nian Wang ◽  
Yan Lu ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Ionizing Radiation ◽  
Lung Injury ◽  
Calcium Influx ◽  
Radiation Induced ◽  
Lung Endothelial Cells

Pulmonary endothelial cell dysfunction plays an important role in ionizing radiation (IR)-induced lung injury. Whether pulmonary endothelial cell ferroptosis occurs after IR and what are the underlying mechanisms remain elusive. Here, we demonstrate that 15-Gy IR induced ferroptosis characterized by lethal accumulation of reactive oxygen species (ROS), lipid peroxidation, mitochondria shrinkage, and decreased glutathione peroxidase 4 (GPX4) and SLC7A11 expression in pulmonary endothelial cells. The phenomena could be mimicked by Yoda1, a specific activator of mechanosensitive calcium channel PIEZO1. PIEZO1 protein expression was upregulated by IR in vivo and in vitro. The increased PIEZO1 expression after IR was accompanied with increased calcium influx and increased calpain activity. The effects of radiation on lung endothelial cell ferroptosis was partly reversed by inhibition of PIEZO1 activity using the selective inhibitor GsMTx4 or inhibition of downstreaming Ca2+/calpain signaling using PD151746. Both IR and activation of PIEZO1 led to increased degradation of VE-cadherin, while PD151746 blocked these effects. VE-cadherin knockdown by specific siRNA causes ferroptosis-like phenomena with increased ROS and lipid peroxidation in the lung endothelial cells. Overexpression of VE-cadherin partly recused the ferroptosis caused by IR or PIEZO1 activation as supported by decreased ROS production, lipid peroxidation and mitochondria shrinkage compared to IR or PIEZO1 activation alone. In summary, our study reveals a previously unrecognized role of PIEZO1 in modulating ferroptosis, providing a new target for future mitigation of radiation-induced lung injury.

scholarly journals Exosomal miR-30d-5p of neutrophils induces M1 macrophage polarization and primes macrophage pyroptosis in sepsis-related acute lung injury

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Yang Jiao ◽  
Ti Zhang ◽  
Chengmi Zhang ◽  
Haiying Ji ◽  
Xingyu Tong ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Macrophage Activation ◽  
Macrophage Polarization ◽  
Cytokine Signaling ◽  
Raw264.7 Macrophages ◽  
M1 Macrophage ◽  
Tnf Α

Abstract Background Polymorphonuclear neutrophils (PMNs) play an important role in sepsis-related acute lung injury (ALI). Accumulating evidence suggests PMN-derived exosomes as a new subcellular entity acting as a fundamental link between PMN-driven inflammation and tissue damage. However, the role of PMN-derived exosomes in sepsis-related ALI and the underlying mechanisms remains unclear. Methods Tumor necrosis factor-α (TNF-α), a key regulator of innate immunity in sepsis-related ALI, was used to stimulate PMNs from healthy C57BL/6J mice in vitro. Exosomes isolated from the supernatant were injected to C57BL/6J wild-type mice intraperitoneally (i.p.) and then examined for lung inflammation, macrophage (Mϕ) polarization and pyroptosis. In vitro co-culture system was applied where the mouse Raw264.7 macrophages or bone marrow-derived macrophages (BMDMs) were co-cultured with PMN-derived exosomes to further confirm the results of in vivo animal study and explore the potential mechanisms involved. Results Exosomes released by TNF-α-stimulated PMNs (TNF-Exo) promoted M1 macrophage activation after in vivo i.p. injection or in vitro co-culture. In addition, TNF-Exo primed macrophage for pyroptosis by upregulating NOD-like receptor 3 (NLRP3) inflammasome expression through nuclear factor κB (NF-κB) signaling pathway. Mechanistic studies demonstrated that miR-30d-5p mediated the function of TNF-Exo by targeting suppressor of cytokine signaling (SOCS-1) and sirtuin 1 (SIRT1) in macrophages. Furthermore, intravenous administration of miR-30d-5p inhibitors significantly decreased TNF-Exo or cecal ligation and puncture (CLP)-induced M1 macrophage activation and macrophage death in the lung, as well as the histological lesions. Conclusions The present study demonstrated that exosomal miR-30d-5p from PMNs contributed to sepsis-related ALI by inducing M1 macrophage polarization and priming macrophage pyroptosis through activating NF-κB signaling. These findings suggest a novel mechanism of PMN-Mϕ interaction in sepsis-related ALI, which may provide new therapeutic strategies in sepsis patients.

scholarly journals High tidal volume upregulates intrapulmonary cytokines in an in vivo mouse model of ventilator-induced lung injury

2003 ◽  
Vol 95 (4) ◽  
pp. 1385-1393 ◽  
Author(s):  
Michael R. Wilson ◽  
Sharmila Choudhury ◽  
Michael E. Goddard ◽  
Kieran P. O'Dea ◽  
Andrew G. Nicholson ◽  
...  
Keyword(s):  
Lung Injury ◽  
Mouse Model ◽  
Tidal Volume ◽  
Lavage Fluid ◽  
Lung Lavage ◽  
High Tidal Volume ◽  
Lung Pathology ◽  
Ventilator Induced Lung Injury ◽  
Tnf Α

Mechanical ventilation has been demonstrated to exacerbate lung injury, and a sufficiently high tidal volume can induce injury in otherwise healthy lungs. However, it remains controversial whether injurious ventilation per se, without preceding lung injury, can initiate cytokine-mediated pulmonary inflammation. To address this, we developed an in vivo mouse model of acute lung injury produced by high tidal volume (Vt) ventilation. Anesthetized C57BL6 mice were ventilated at high Vt (34.5 ± 2.9 ml/kg, mean ± SD) for a duration of 156 ± 17 min until mean blood pressure fell below 45 mmHg ( series 1); high Vt for 120 min ( series 2); or low Vt (8.8 ± 0.5 ml/kg) for 120 or 180 min ( series 3). High Vt produced progressive lung injury with a decrease in respiratory system compliance, increase in protein concentration in lung lavage fluid, and lung pathology showing hyaline membrane formation. High-Vt ventilation was associated with increased TNF-α in lung lavage fluid at the early stage of injury ( series 2) but not the later stage ( series 1). In contrast, lavage fluid macrophage inflammatory protein-2 (MIP-2) was increased in all high-Vt animals. Lavage fluid from high-Vt animals contained bioactive TNF-α by WEHI bioassay. Low-Vt ventilation induced minimal changes in physiology and pathology with negligible TNF-α and MIP-2 proteins and TNF-α bioactivity. These results demonstrate that high-Vt ventilation in the absence of underlying injury induces intrapulmonary TNF-α and MIP-2 expression in mice. The apparently transient nature of TNF-α upregulation may help explain previous controversy regarding the involvement of cytokines in ventilator-induced lung injury.

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