Current knowledge of acute lung injury and acute respiratory distress syndrome

CMTM3 regulates vascular endothelial cell dysfunction by influencing pulmonary vascular endothelial permeability and inflammation in ARDS

Introduction

CMTM3 is a member of the human chemokine-like factor superfamily. The mechanistic role of CMTM3 in acute respiratory distress syndrome (ARDS) is not known. This study investigated the role of CMTM3 in the progression of ARDS and its impact on the function of vascular endothelial cells.

Methods

ARDS modeling in human umbilical vascular endothelial cells (HUVECs) was performed by treating with lipopolysaccharide (LPS) or hypoxia/reoxygenation. We assessed CMTM3 expression levels in the LPS- and hypoxia/reoxygenation-stimulated HUVEC cells. Furthermore, we assessed the role of CMTM3 in the permeability function and inflammatory response of the vascular endothelial cells under ARDS conditions using HUVEC cells with CMTM3 overexpression(adCMTM3) or knockdown(shCMTM3). Concurrently, we generated CMTM3 knockout (CMTM3ko) mice and evaluated the differences in pulmonary vascular permeability, inflammatory lung injury, and survival rates between the CMTM3ko-ARDS and WT-ARDS model mice.

Results

HUVECs stimulated with LPS and hypoxia/reoxygenation showed significantly higher CMTM3 expression compared to the control group (p<0.05). Compared with the adsham-HUVECs, adCMTM3-HUVECs stimulated with LPS and hypoxia/reoxygenation demonstrated significantly higher cellular permeability (p<0.05) as well as IL-6 and TNF-α expression levels (p<0.05). Conversely, shCMTM3-HUVECs stimulated with LPS and hypoxia/reoxygenation showed significantly reduced cellular permeability as well as IL-6 and TNF-α expression levels (p<0.05). In vivo ARDS modeling experiments demonstrated that CMTM3-knockout ARDS mice exhibited significantly higher survival rates (p=0.0194) as well as significantly reduced lung injury and pulmonary vascular permeability (p<0.05) compared to the wild-type ARDS mice.

Discussion

These findings demonstrated that CMTM3 played a critical role in the development of ARDS by influencing permeability of the pulmonary vascular endothelial cells and lung inflammation. Therefore, CMTM3 is a potential therapeutic target in ARDS.

Cross-Sectional and Longitudinal Associations of Serum LRG1 with Severity and Prognosis Among Adult Community-Acquired Pneumonia Patients

Background

Leucine-rich α-2 glycoprotein 1 (LRG1) is associated with various inflammatory lung diseases. Nevertheless, the connection between LRG1 and adult community-acquired pneumonia (CAP) individuals was still not well understood. Through a prospective cohort study, the correlations of serum LRG1 with severity and prognosis were evaluated in CAP patients.

Methods

The study encompassed 327 patients who received the diagnosis of CAP. We collected fasting venous blood and clinical features. Serum LRG1 was detected by ELISA. CAP severity was assessed using various scoring systems. The prognostic outcomes were observed through follow-up visits.

Results

The level of serum LRG1 at admission was gradually increased with CAP severity scores. Serum LRG1 level shown positive associations with inflammatory indices, including C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6). Linear and logistic regression analyses suggested that serum LRG1 at admission was positively associated with severity scores and the risk of death in CAP patients. Serum LRG1 in combination with CAP severity scores significantly increased the predictive powers for severity and death compared with single serum LRG1 or severity scores.

Conclusion

The study revealed positive connections of serum LRG1 levels with severity and poor prognosis in CAP patients, suggesting LRG1 partakes into the physiological processes of CAP. Serum LRG1 may be regarded as a potential biomarker in predicting the severity and death among CAP patients.

Tribuloside: Mechanisms and Efficacy in Treating Acute Lung Injury Revealed by Network Pharmacology and Experimental Validation

Background

Acute lung injury (ALI) is a serious illness that has few treatment options available. Tribuloside, a natural flavonoid extracted from the Tribulus Terrestris plant in China, is potent in addressing many health issues such as headaches, dizziness, itching, and vitiligo.

Objective

This study intends to explore the mechanisms of action of Tribuloside in treating ALI through a combination of network pharmacology and experimental validation.

Methods

We obtained the 2D structure and SMILES number of Tribuloside from the PubChem database. We used the SwissTargetPrediction database to identify pharmacological targets. We found 1215 targets linked to ALI by examining the GeneCards database. We used the String database and Cytoscape software to create the "drug or disease-target" network as well as the protein-protein interactions (PPI). Key targets were identified by evaluating associated biological processes and pathway enrichment. A Venny Diagram showed 49 intersection points between Tribuloside and ALI. Molecular docking with AutoDockTools found that Tribuloside had a high affinity for IL6, BCL2, TNF, STAT3, IL1B, and MAPK3, the top 6 targets in the PPI network by Degree values. To test Tribuloside's therapeutic efficacy in ALI, an acute lung damage model in mice was constructed using lipopolysaccharide. Tribuloside treatment reduced inflammatory cell infiltration, decreased fibrotic area, repaired damaged alveoli, and suppressed inflammatory factors IL-6, TNF-α, and IL-1β in the lungs through many pathways and targets.

Conclusion

This study reveals that Tribuloside has the potential to treat ALI by targeting various pathways and targets, according to network pharmacology predictions and experimental confirmation.

Qi-Dong-Huo-Xue-Yin Inhibits Inflammation in Acute Lung Injury in Mice via Toll-Like Receptor 4/Caveolin-1 Signaling

Acute lung injury (ALI) is a critical illness with no current effective treatment. Caveolin-1 indirectly activates inflammation-associated signaling pathways by inhibiting endothelial nitric oxide synthase (eNOS). This induces an imbalance between pro- and anti-inflammatory cytokine levels, which are involved in the pathogenesis of ALI. The compound Chinese prescription Qi-Dong-Huo-Xue-Yin (QDHXY) is efficacious for ALI treatment via an anti-inflammatory effect; however, the exact underlying mechanism is unknown. Therefore, we explored the protective effect of QDHXY against lipopolysaccharide- (LPS-) induced ALI in mice. Histopathological changes in mouse lung tissues were studied. Furthermore, alterations in the serum levels of pro- and anti-inflammatory cytokines were investigated. The levels of tumor necrosis factor- (TNF-)α, interleukin- (IL-) 6, IL-1β, and interferon-γ-induced protein 10 in bronchoalveolar lavage fluid were measured. Additionally, the expression levels of myeloid differentiation factor 88 (MyD88), caveolin-1, and eNOS were assessed. QDHXY significantly reduced lung infiltration with inflammatory cells and the production of serum pro- and anti-inflammatory cytokines and inhibited the expression of TNF-α, IL-1β, caveolin-1, and MyD88 but not eNOS. These indicate that QDHXY significantly improved the balance between pro- and anti-inflammatory cytokine levels, possibly by inhibiting the caveolin-1 signaling pathway. Therefore, QDHXY may be a potential treatment for ALI.

Adenovirus-delivered angiopoietin-1 suppresses NF-κB and p38 MAPK and attenuates inflammatory responses in phosgene-induced acute lung injury

Animals exposed to phosgene (Psg) result in acute lung injury (ALI). We have recently reported that angiopoietin-1 (Ang1) reduces inflammation and vascular hyperpermeability in ALI animals. In this study, we examined whether the beneficial effects of adenovirus-delivered Ang1 (Ad/Ang1) on inflammatory responses in Psg-induced ALI rats are due to the suppression of the nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) pathways, which play crucial roles in inflammatory responses in ALI. We demonstrated that Psg increased Ang2 and inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-4 (IL-4), IL-6, IL-8, and IL-10, in the serum and bronchoalveolar lavage fluid of ALI rats, determined by ELISA. Ang1 inhibits pro-inflammatory mediators (TNF-α, IL-6 and IL-8) and has no effect on anti-inflammatory mediators (IL-4 and IL-10). Furthermore, the inhibitory action of Ang1 was mediated by the suppression of the NF-κB and p38 MAPK pathways, leading to the attenuation of inflammatory responses of ALI. Thus, Ad/Ang1 may provide a useful tool for the effective treatment in Psg-induced ALI.