Progression Of Acute Lung Injury Research Articles

Essential blood molecular signature for progression of sepsis-induced acute lung injury: Integrated bioinformatic, single-cell RNA Seq and machine learning analysis.

In this study, we aimed to identify an essential blood molecular signature for chacterizing the progression of sepsis-induced acute lung injury using integrated bioinformatic and machine learning analysis. The results showed that a total of 88 functionally related ALI-associated hub genes in sepsis were identified by MCODE analysis and they were enriched in infection and inflammtory responses, lung and cardiovascular disease pathways. These hub genes stratified ALI-sepsis and sepsis and further stratified two subtypes of sepsis-ALI with differential ALI scores, hub gene expression patterns, and levels of immune cells. A seven-gene signature including TNFRSF1A, NFKB1, FCGR2A, NFE2L2, ICAM1 and SOCS3 and PDCD1 was derived from the hub genes. These genes were significantly implicated in immune and metabolism pathways. They were expressed in six circulatory immune cells based on analysis of a single cell RNA sequencing dataset. Furthermore, the seven-gene signature was corrobarated using by integrating 12 machine learning algorithms. A premium three-gene signature NFE2L2, FCGR2A and PDCD1 for differentiating ALI-sepsis from sepsis were also derived from the seven-gene signature based on analysis of the seven core hub genes by the machine learning algorithms. Furthermore, the expressions of hub genes were verified in sepsis mice models. Therefore, our study provided an avenue to develop a molecular tool for identify and characterize progression of acute lung injury associated with sepsis.

Intranasal administration of Clostridium butyricum and its derived extracellular vesicles alleviate LPS-induced acute lung injury.

Acute lung injury (ALI) is associated with high morbidity and mortality rates. However, its clinical treatment is limited. Currently, the treatment of lung diseases by regulating the lung microbiota has become a research hotspot. In this study, we investigated the protective effects of the intranasal administration of Clostridium butyricum and its derived extracellular vesicles (EVs) against lipopolysaccharide (LPS)-induced ALI. The results demonstrated that compared with the LPS group, the pre-treatment group with C. butyricum and its EVs reduced the expression of pro-inflammatory cytokines and alleviated the symptoms in ALI mice by inhibiting the TLR4/MyD88 signaling pathway. Moreover, C. butyricum and its derived EVs inhibited the expression of apoptosis-related proteins and increased the expression of lung barrier proteins. Additionally, the intervention of C. butyricum changed the composition of the pulmonary microbiota. At the species level, LPS significantly increased the relative abundance of Acinetobacter johnsonii, while C. butyricum reversed this effect. In conclusion, these data demonstrate that intranasal administration of C. butyricum and its EVs can prevent LPS-induced ALI by reducing inflammation, inhibiting apoptosis, and improving lung barrier function. Additionally, C. butyricum regulated the pulmonary microbiota of mice to alleviate LPS-induced ALI.IMPORTANCEThe disorder of pulmonary microbiota plays an important role in the progression of acute lung injury (ALI). However, very few studies have been conducted to treat ALI by modulating pulmonary microbiota. In this study, the diversity and composition of pulmonary microbiota were altered in lipopolysaccharide (LPS)-induced ALI mice, but the ecological balance of the pulmonary microbiota was restored by intranasal administration of Clostridium butyricum. Moreover, the study reported the mechanism of C. butyricum and its derived extracellular vesicles for the treatment of LPS-induced ALI. These results reveal the importance of pulmonary microbiota in ALI disease. It provides a new approach for the treatment of ALI with new-generation probiotics.

Impact of Curcumin on the IL-17A-Mediated p53-Fibrinolytic System: Mouse Proteomics and Integrated Human Fibrosis scRNAseq Insights.

Acute lung injury (ALI) is primarily driven by an intense inflammation in the alveolar epithelium. Key to this is the pro-inflammatory cytokine, Interleukin 17 (IL-17), which influences pulmonary immunity and modifies p53 function. The direct role of IL-17A in p53-fibrinolytic system is still unclear, it is important to evaluate this mechanism to regulate the ALI progression to idiopathic pulmonary fibrosis (IPF). C57BL/6 mice, exposed to recombinant IL-17A protein and treated with curcumin, provided insight into IL-17A mechanisms and curcumin's potential for modulating early pulmonary fibrosis stages. A diverse methodology, including proteomics, single-cell RNA sequencing (scRNA-seq) integration, molecular, and Schroedinger approach were utilized. In silico approaches facilitated the potential interactions between curcumin, IL-17A, and apoptosis-related proteins. A notable surge in the expression levels of IL-17A, p53, and fibrinolytic components such as Plasminogen Activator Inhibitor-1 (PAI-I) was discerned upon the IL17A exposure in mouse lungs. Furthermore, the enrichment of pathways and differential expression of proteins underscored the significance of IL-17A in governing downstream regulatory pathways such as inflammation, NF-kappaB signaling, Mitogen-Activated Protein Kinases (MAPK), p53, oxidative phosphorylation, JAK-STAT, and apoptosis. The integration of scRNA-seq data from 20 IPF and 10 control lung specimens emphasized the importance of IL-17A mediated downstream regulation in PF patients. A potent immuno-pharmacotherapeutic agent, curcumin, demonstrated a substantial capacity to modulate the lung pathology and molecular changes induced by IL-17A in mouse lungs. Human IPF single cell data integration confirmed the effects of IL-17A mediated fibrinolytic components in ALI to IPF progression.

Tulipalin A suppressed the pro-inflammatory polarization of M1 macrophage and mitigated the acute lung injury in mice via interference DNA binding activity of NF-κB

Acute lung injury (ALI) is an inflammatory disorder accompanied by higher morbidity and mortality. The pathological mechanism of ALI has been reported to be associated with the release of inflammatory cytokines by macrophages. Sesquiterpene lactones (SLs) represent the principal anti-inflammatory components of many natural products. Tulipalin A is a natural small molecule and a conserved moiety in anti-inflammatory SLs. However, the anti-inflammatory potential of Tulipalin A has yet to be fully disclosed. The present study aims to investigate TulipalinA's anti-inflammatory activity and underlying mechanisms in vitro and in vivo. Tulipalin A suppressed inflammatory responses in lipopolysaccharide (LPS)-stimulated bone marrow-derived primary macrophages and ameliorated LPS-induced ALI in mice. Mechanistically, Tulipalin A directly targets the NF-κB p65 and disrupts its DNA binding activity, thereby impeding the activation of NF-κB. Inhibition of NF-κB attenuated M1 polarization of macrophages, consequently suppressing the production of pro-inflammatory mediators and ameliorating the onset and progression of ALI. These findings suggest Tulipalin A's potential to mitigate inflammatory disorders like ALI via targeting NF-κB p65 and disrupting its DNA binding activity.

VEGFR1 TK signaling protects the lungs against LPS-induced injury by suppressing the activity of alveolar macrophages and enhancing the anti-inflammatory function of monocyte-derived macrophages

Acute lung injury (ALI) is characterized by hyperinflammation followed by vascular leakage and respiratory failure. Vascular endothelial growth factor (VEGF)-A is critical for capillary permeability; however, the role of VEGF receptor 1 (VEGFR1) signaling in ALI progression remains unclear. Here, we show that deletion of VEGFR1 tyrosine kinase (TK) signaling in mice exacerbates lipopolysaccharide (LPS)-induced ALI as evidenced by excessive pro-inflammatory cytokine production and interleukin(IL)-1β-producing neutrophil recruitment to inflamed lung tissues. ALI development involves reduced alveolar macrophage (AM) levels and recruitment of monocyte-derived macrophages (MDMs) in a VEGFR1 TK-dependent manner. VEGFR1 TK signaling reduced pro-inflammatory cytokine levels in cultured AMs. VEGFR1 TK-expressing MDMs displayed an anti-inflammatory macrophage phenotype. Additionally, the transplantation of VEGFR1 TK-expressing bone marrow (BM)-derived macrophages into VEGFR1 TK-deficient mice reduced lung inflammation. Treatment with placental growth factor (PlGF), an agonist for VEGFR1, protected the lung against LPS-induced ALI associated with increased MDMs. These results suggest that VEGFR1 TK signaling prevents LPS-induced ALI by suppressing the pro-inflammatory activity of AMs and enhancing the anti-inflammatory function of MDMs.

METTL3-m6A methylation inhibits the proliferation and viability of type II alveolar epithelial cells in acute lung injury by enhancing the stability and translation efficiency of Pten mRNA

BackgroundThe pathogenesis of acute lung injury (ALI) involves a severe inflammatory response, leading to significant morbidity and mortality. N6-methylation of adenosine (m6A), an abundant mRNA nucleotide modification, plays a crucial role in regulating mRNA metabolism and function. However, the precise impact of m6A modifications on the progression of ALI remains elusive.MethodsALI models were induced by either intraperitoneal injection of lipopolysaccharide (LPS) into C57BL/6 mice or the LPS-treated alveolar type II epithelial cells (AECII) in vitro. The viability and proliferation of AECII were assessed using CCK-8 and EdU assays. The whole-body plethysmography was used to record the general respiratory functions. M6A RNA methylation level of AECII after LPS insults was detected, and then the “writer” of m6A modifications was screened. Afterwards, we successfully identified the targets that underwent m6A methylation mediated by METTL3, a methyltransferase-like enzyme. Last, we evaluated the regulatory role of METTL3-medited m6A methylation at phosphatase and tensin homolog (Pten) in ALI, by assessing the proliferation, viability and inflammation of AECII.ResultsLPS induced marked damages in respiratory functions and cellular injuries of AECII. The m6A modification level in mRNA and the expression of METTL3, an m6A methyltransferase, exhibited a notable rise in both lung tissues of ALI mice and cultured AECII cells subjected to LPS treatment. METTL3 knockdown or inhibition improved the viability and proliferation of LPS-treated AECII, and also reduced the m6A modification level. In addition, the stability and translation of Pten mRNA were enhanced by METTL3-mediated m6A modification, and over-expression of PTEN reversed the protective effect of METTL3 knockdown in the LPS-treated AECII.ConclusionsThe progression of ALI can be attributed to the elevated levels of METTL3 in AECII, as it promotes the stability and translation of Pten mRNA through m6A modification. This suggests that targeting METTL3 could offer a novel approach for treating ALI.

High Levels of Triggering Receptor Expressed in Myeloid Cells-Like Transcript-1 Positive, but Not Glycoprotein 1b+, Microparticles Are Associated With Poor Outcomes in Acute Respiratory Distress Syndrome.

To identify triggering receptor expressed in myeloid cells-like transcript-1 positive (TLT-1+) microparticles (MPs) and evaluate if their presence is associated with clinical outcomes and/or disease severity in acute respiratory distress syndrome (ARDS). Retrospective cohort study. ARDS Network clinical trials. A total of 564 patients were diagnosed with ARDS. None. Using flow cytometry, we demonstrated the presence of TLT-1+ platelet-derived microparticles (PMP) that bind fibrinogen in plasma samples from fresh donors. We retrospectively quantified TLT-1, glycoprotein (Gp) 1b, or αIIbβIIIa immunopositive microparticles in plasma samples from patients with ARDS enrolled in the ARMA, KARMA, and LARMA (Studies 01 and 03 lower versus higher tidal volume, ketoconazole treatment, and lisofylline treatment Clincial Trials) ARDS Network clinical trials and evaluated the relationship between these measures and clinical outcomes. No associations were found between Gp1b+ MPs and clinical outcomes for any of the cohorts. When stratified by quartile, associations were found for survival, ventilation-free breathing, and thrombocytopenia with αIIbβIIIa+ and TLT-1+ MPs (χ2p < 0.001). Notably, 63 of 64 patients in this study who failed to achieve unassisted breathing had TLT+ PMP in the 75th percentile. In all three cohorts, patients whose TLT+ MP counts were higher than the median had higher Acute Physiology and Chronic Health Evaluation III scores, were more likely to present with thrombocytopenia and were 3.7 times (p < 0.001) more likely to die than patients with lower TLT+ PMP after adjusting for other risk factors. Although both αIIbβIIIa+ and TLT+ microparticles (αIIbβIIIa, TLT-1) were associated with mortality, TLT-1+ MPs demonstrated stronger correlations with Acute Physiology and Chronic Health Evaluation III scores, unassisted breathing, and multiple system organ failure. These findings warrant further exploration of the mechanistic role of TLT-1+ PMP in ARDS or acute lung injury progression.

Alleviating Acute Lung Injury Induced by Lipopolysaccharide: Dayuan Yin Suppresses Inflammation and Oxidative Stress in Elderly Male Rats.

The occurrence of acute lung injury (ALI) caused by lipopolysaccharide (LPS) is prevalent and perilous among older individuals. Inflammation and oxidative stress are vital factors in the progression of ALI in this population. Dayuan Yin (DYY) is a classic Chinese herbal formula used for treating pulmonary diseases. Therefore，this situation can be well simulated by selecting suitable aged rats and induced by LPS, which is helpful to evaluate the role of DYY. The objective of this study is to assess the therapeutic efficacy of DYY in reducing pulmonary inflammation and oxidative stress injury in aged rats induced by LPS. In elderly male Sprague Dawley (SD) rats, the ALI model was induced by injecting LPS into the peritoneal cavity. The therapeutic effect of the DYY group was evaluated after 3 days of oral administration. Lung tissue damage was assessed using hematoxylin-eosin staining and the lung wet/dry (W/D) ratio. Inflammatory reaction in lung tissue was analyzed by counting inflammatory agents, measuring total protein (TP), and examining the concentration of inflammatory components in bronchoalveolar lavage fluid (BALF). Lung oxidative stress was assessed by measuring malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), and superoxide dismutase (SOD) levels in BALF. The impact of DYY on the phosphorylation of PI3K, AKT, and NF-κBp65 protein was analyzed using Western Blot (WB). The administration of DYY exhibited a dose-dependent reduction in the severity of lung injury caused by LPS, leading to a reversal of the LPS-induced lung W/D ratio. Furthermore, DYY treatment resulted in decreased levels of leukocytes, eosinophils, neutrophils, macrophages, lymphocytes, and total protein in BALF. Additionally, DYY significantly inhibited the upregulation of Interleukin -6, Interleukin -10, and Interleukin -1β (IL-6, IL-10, IL-1β) as well as Tumor necrosis factor-α(TNF-α) induced by LPS (P<0.01). The lungs experienced oxidative stress due to LPS, leading to the production of MDA and iNOS, as well as a decrease in SOD activity. DYY reduced oxidative stress in the lungs and inhibited the activation of p-PI3K, p-Akt, and p-NF-κBp65, with a greater effect at higher doses. In a dose-dependent manner, DYY suppresses the inflammatory response and oxidative stress in the lung tissue of elderly rats, thereby reducing ALI caused by LPS. This effect may be attributed to the inhibition of the PI3K/AKT/NF-κB pathway activation.

Hyaluronan Fragments Induce Lung Alveolar Edema by Activating Calcium-Sensing Receptor

One of the hallmarks of lung injury is the breakdown of the cell matrix hygroscopic high molecular weight hyaluronan (HMW-HA &gt;106 kD) into smaller fragments of low molecular weight (LMW-HA &lt; 500 kD) which mediate the onset and progression of acute lung injury. We have found that instillation of very low dose (1μg) of LMW-HA to wt. C57/bl6 mice was suffcient to inhibit lung epithelial ions and water transport and cause lung edema assessed by measuring lungs wet/dry ratio. LMW-HA IC50 for the induction of lung edema, the inhibition of alveolar fluid clearance (AFC) and epithelial sodium channels (ENaC) in alveolar epithelial cells, AEC1 and AEC2, in-situ, in freshly cut lung slices, was 120 nM. We found the expression of calcium-sensing receptor (CaSR), a C class G-protein coupled receptor, was activated by LMW-HA. CD44 is known to be the main membrane receptor of hyaluronan expressed by most cells including lung alveolar epithelial cells, however, because it lacks the intrinsic kinase activity necessary for the transduction of extracellular signal carried by LMW-HA, we hypothesized that it cooperated with CaSR to transduce LMW-HA injurious signal and activated intracellular signaling cascades that induced lung edema by inhibiting ENaC and AFC at 24 h. These effects were prevented by NPS2143 (1 μM), a CaSR inhibitor or calcilytic, instilled 6 h post LMW-HA, and were absent in CD44 knockout mouse. The lack of an effect on W/D ratio, AFC, or ENaC in CD44−/− mouse is evidence that LMW-HA does not directly interact with CaSR, but rather activates CD44 which cooperate with CaSR to trigger intracellular signaling cascades that cause the observed effects. Four hours post mouse airway epithelial cells confluent monolayers were incubated with 1 μg LMW-HA, CaSR expression was increased 4-fold, while amiloride sensitive short-circuit current and αβγ-ENaC subunits expression, at the apical membranes, were significantly reduced. These effects were prevented when CaSR, PLC, or PKC were inhibited with 1 μM NPS2143, 10 μM U73122, or 100 μM Rottlerin, applied 4 h prior to cells incubation with 1 μg LMW-HA, respectively. Our data show that the deleterious effect of LMW-HA on ENaC are mediated by intricate interactions between CD44-LMW-HA complex with CaSR in lung alveolar epithelial cells. The use of calcilytics to decouple the molecular complex formed by CD44-LMW-HA and CaSR may prove to be effective in restoring alveolar sodium ion reabsorption required for lung edema clearance. Department of Anesthesiology and Perioperative Medicine. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

ACE2 and a Traditional Chinese Medicine Formula NRICM101 Could Alleviate the Inflammation and Pathogenic Process of Acute Lung Injury

The coronavirus disease 2019 (COVID-19) is a highly transmittable respiratory illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and acute lung injury (ALI) is the major complication of COVID-19. The challenge in studying SARS-CoV-2 pathogenicity is the limited availability of animal model. Therefore, it is necessary to establish animal models that can reproduce multiple characteristics of ALI to study therapeutic application. The present study established a mouse model that has features of ALI that are similar to COVID-19 syndrome to investigate the role of human angiotensin-converting enzyme type II (ACE2) and the administration of the Chinese herbal prescription Chingguan Yihau (NRICM101) in ALI. The mice with ACE2 genetic modifications, including the overexpression of human ACE2 (K18-hACE2 TG) and the absence of ACE2 (mACE2 KO), were intratracheally instillated with hydrochloric acid to induce ALI. The acid intratracheal instillation induced the imbalance between angiotensin-converting enzyme (ACE) and ACE2 (i.e., ACE/ACE2), severe immune cell infiltration, cytokine storms, inflammatory effect, and pulmonary disease in the mice. Compared with K18-hACE2 TG mice, mACE2 KO mice exhibited dramatically increased levels of multiple inflammatory cytokines Interleukin-6 (IL-6) and Tumor necrosis factor alpha (TNF-α) in bronchoalveolar lavage fluid, histological evidence of lung injury, the production of the ACE expression, and the activation of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) expression. The results indicate that overproduction of ACE2 and induction of the ACE2-Ang-(1-7)/Mas axis could counteract the proinflammatory effect of acid-induced ALI and effectively alleviate the pathogenic process of acid-induced ALI by regulating MAPK, p-ERK1/2, and p-STAT3 pathways and dysregulation of MMP-2/MMP-9 activation. In addition, NRICM101, which is an effective TCM that has both antiviral and anti-inflammatory effects against COVID-19, shows potential for treating acid-induced ALI. NRICM101 could alleviate the disease progression of acid-induced ALI by suppressing IL-6 and TNF-α production in alveoli. In conclusion, the established mouse model provided an effective platform for researchers to investigate the role of ACE2 on pathological mechanisms and develop therapeutic strategies for ALI, including COVID-19-related pulmonary diseases. The effects of NRICM101 administration is a potential strategy for curing acid-induced ALI evaluated in the mouse model in this study. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ginsenoside Rg1 Alleviates Sepsis-Induced Acute Lung Injury by Reducing FBXO3 Stability in an m6A-Dependent Manner to Activate PGC-1α/Nrf2 Signaling Pathway.

Sepsis-induced acute lung injury (ALI) is one of the serious life-threatening complications of sepsis and is pathologically associated with mitochondrial dysfunction. Ginsenoside Rg1 has good therapeutic effects on ALI. Herein, the pharmacological effects of Rg1 in sepsis-induced ALI were investigated. Sepsis-induced ALI models were established by CLP operation and LPS treatment. HE staining was adopted to analyze lung pathological changes. The expression and secretion of cytokines were measured by RT-qPCR and ELISA. Cell viability and apoptosis were assessed by MTT assay, flow cytometry and TUNEL staining. ROS level and mitochondrial membrane potential (MMP) were analyzed using DHE probe and JC-1 staining, respectively. FBXO3 m6A level was assessed using MeRIP assay. The interactions between FBXO3, YTHDF1, and PGC-1α were analyzed by Co-IP or RIP. Rg1 administration ameliorated LPS-induced epithelial cell inflammation, apoptosis, and mitochondrial dysfunction in a dose-dependent manner. Mechanically, Rg1 reduced PGC-1α ubiquitination modification level by inhibiting FBXO3 expression m6A-YTHDF1 dependently. As expected, Rg1's mitigative effect on LPS-induced inflammation, apoptosis and mitochondrial dysfunction in lung epithelial cells was abolished by FBXO3 overexpression. Moreover, FBXO3 upregulation eliminated the restoring effect of Rg1 on CLP-induced lung injury in rats. Rg1 activated PGC-1α/Nrf2 signaling pathway by reducing FBXO3 stability in an m6A-YTHDF1-dependent manner to improve mitochondrial function in lung epithelial cells during sepsis-induced ALI progression.

Exosomal Tenascin-C primes macrophage pyroptosis amplifying aberrant inflammation during sepsis-induced acute lung injury

Sepsis-induced acute lung injury (ALI) is a serious complication of sepsis and the predominant cause of death. Exosomes released by lung tissue cells critically influence the progression of ALI during sepsis by modulating the inflammatory microenvironment. However, the molecular mechanisms by which exosome-mediated intercellular signaling exacerbates ALI in septic infection remain undefined. Our study found increased levels of exosomal Tenascin-C (TNC) in the plasma of both patients and mice with ALI, showing a strong association with disease progression. By integrating exosomal proteomics with transcriptome sequencing and experimental validation, we elucidated that LPS induce unresolved endoplasmic reticulum stress (ERs) in alveolar epithelial cells (AECs), ultimately leading to the release of exosomal TNC through the activation of PERK-eIF2α and the transcription factor CHOP. In the sepsis mouse model with TNC knockout, we noted a marked reduction in macrophage pyroptosis. Our detailed investigations found that exosomal TNC binds to TLR4 on macrophages, resulting in an augmented production of ROS, subsequent mitochondrial damage, activation of the NF-κB signaling pathway, and induction of DNA damage response. These interconnected events culminate in macrophage pyroptosis, thereby amplifying the release of inflammatory cytokines. Our findings demonstrate that exosomal Tenascin-C, released from AECs under unresolved ER stress, exacerbates acute lung injury by intensifying sepsis-associated inflammatory responses. This research provides new insights into the complex cellular interactions underlying sepsis-induced ALI.

Identification of HK3 as a promising immunomodulatory and prognostic target in sepsis-induced acute lung injury

BackgroundSepsis is a life-threatening global disease with a significant impact on human health. Acute lung injury (ALI) has been identified as one of the primary causes of mortality in septic patients. This study aimed to identify candidate genes involved in sepsis-induced ALI through a comprehensive approach combining bioinformatics analysis and experimental validation. MethodsThe datasets GSE65682 and GSE32707 obtained from the Gene Expression Omnibus database were merged to screen for sepsis-induced ALI related differentially expressed genes (DEGs). Functional enrichment and immune infiltration analyses were conducted on DGEs, with the construction of protein-protein interaction (PPI) networks to identify hub genes. In vitro and in vivo models of sepsis-induced ALI were used to study the expression and function of hexokinase 3 (HK3) using various techniques including Western blot, real-time PCR, immunohistochemistry, immunofluorescence, Cell Counting Kit-8, Enzyme-linked immunosorbent assay, and flow cytometry. ResultsThe results of bioinformatics analysis have identified HK3, MMP9, and S100A8 as hub genes with diagnostic and prognostic significance for sepsis-induced ALI. The HK3 has profound effects on sepsis-induced ALI and exhibits a correlation with immune regulation. Experimental results showed increased HK3 expression in lung tissue of septic mice, particularly in bronchial and alveolar epithelial cells. In vitro studies demonstrated upregulation of HK3 in lipopolysaccharide (LPS)-stimulated lung epithelial cells, with cytoplasmic localization around the nucleus. Interestingly, following the knockdown of HK3 expression, lung epithelial cells exhibited a significant decrease in proliferation activity and glycolytic flux, accompanied by an increase in cellular inflammatory response, oxidative stress, and cell apoptosis. ConclusionsIt was observed for the first time that HK3 plays a crucial role in the progression of sepsis-induced ALI and may be a valuable target for immunomodulation and therapy.Bioinformatics analysis identified HK3, MMP9, and S100A8 as hub genes with diagnostic and prognostic relevance in sepsis-induced ALI. Experimental findings showed increased HK3 expression in the lung tissue of septic mice, particularly in bronchial and alveolar epithelial cells. In vitro experiments demonstrated increased HK3 levels in lung epithelial cells stimulated with LPS, with cytoplasmic localization near the nucleus. Knockdown of HK3 expression resulted in decreased proliferation activity and glycolytic flux, increased inflammatory response, oxidative stress, and cell apoptosis in lung epithelial cells.

GSTP alleviates acute lung injury by S-glutathionylation of KEAP1 and subsequent activation of NRF2 pathway

Oxidative stress plays an important role in the pathogenesis of acute lung injury (ALI). As a typical post-translational modification triggered by oxidative stress, protein S-glutathionylation (PSSG) is regulated by redox signaling pathways and plays diverse roles in oxidative stress conditions. In this study, we found that GSTP downregulation exacerbated LPS-induced injury in human lung epithelial cells and in mice ALI models, confirming the protective effect of GSTP against ALI both in vitro and in vivo. Additionally, a positive correlation was observed between total PSSG level and GSTP expression level in cells and mice lung tissues. Further results demonstrated that GSTP inhibited KEAP1-NRF2 interaction by promoting PSSG process of KEAP1. By the integration of protein mass spectrometry, molecular docking, and site-mutation validation assays, we identified C434 in KEAP1 as the key PSSG site catalyzed by GSTP, which promoted the dissociation of KEAP1-NRF2 complex and activated the subsequent anti-oxidant genes. In vivo experiments with AAV-GSTP mice confirmed that GSTP inhibited LPS-induced lung inflammation by promoting PSSG of KEAP1 and activating the NRF2 downstream antioxidant pathways. Collectively, this study revealed the novel regulatory mechanism of GSTP in the anti-inflammatory function of lungs by modulating PSSG of KEAP1 and the subsequent KEAP1/NRF2 pathway. Targeting at manipulation of GSTP level or activity might be a promising therapeutic strategy for oxidative stress-induced ALI progression.

Glycogen Synthase Kinase-3 Inhibition by CHIR99021 Promotes Alveolar Epithelial Cell Proliferation and Lung Regeneration in the Lipopolysaccharide-Induced Acute Lung Injury Mouse Model.

Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury that currently lacks effective clinical treatments. Evidence highlights the potential role of glycogen synthase kinase-3 (GSK-3) inhibition in mitigating severe inflammation. The inhibition of GSK-3α/β by CHIR99021 promoted fetal lung progenitor proliferation and maturation of alveolar epithelial cells (AECs). The precise impact of CHIR99021 in lung repair and regeneration during acute lung injury (ALI) remains unexplored. This study intends to elucidate the influence of CHIR99021 on AEC behaviour during the peak of the inflammatory phase of ALI and, after its attenuation, during the repair and regeneration stage. Furthermore, a long-term evaluation was conducted post CHIR99021 treatment at a late phase of the disease. Our results disclosed the role of GSK-3α/β inhibition in promoting AECI and AECII proliferation. Later administration of CHIR99021 during ALI progression contributed to the transdifferentiation of AECII into AECI and an AECI/AECII increase, suggesting its contribution to the renewal of the alveolar epithelial population and lung regeneration. This effect was confirmed to be maintained histologically in the long term. These findings underscore the potential of targeted therapies that modulate GSK-3α/β inhibition, offering innovative approaches for managing acute lung diseases, mostly in later stages where no treatment is available.

GLUT1 regulates the release of VEGF-A in the alveolar epithelium of lipopolysaccharide-induced acute lung injury.

Acute lung injury (ALI) is a severe disease with high mortality and poor prognosis, characterized by excessive and uncontrolled inflammatory response. Vascular endothelial growth factor A (VEGF-A) contributes to the development and progression of ALI. The aim of this study was to evaluate the role of glucose transporter 1 (GLUT1) in alveolar epithelial VEGF-A production in lipopolysaccharide (LPS)-induced ALI. An ALI mouse model was induced by LPS oropharyngeal instillation. Mice were challenged with LPS and then treated with WZB117, a specific antagonist of GLUT1. For the vitro experiments, cultured A549 cells (airway epithelial cell line) were exposed to LPS, with or without the GLUT1 inhibitors WZB117 or BAY876. LPS significantly upregulated of GLUT1 and VEGF-A both in the lung from ALI mice and in cultured A549. In vivo, treatment with WZB117 not only markedly decreased LPS-induced pulmonary edema, injury, neutrophilia, as well as levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF), but also reduced VEGF-A production. Yet, the maximum tolerated concentration of WZB117 failed to suppress LPS-induced VEGF-A overexpression in vitro. While administration of BAY876 inhibited gene and protein expression as well as secretion of VEGF-A in response to LPS in A549. These results illustrated that GLUT1 upregulates VEGF-A production in alveolar epithelia from LPS-induced ALI, and inhibition of GLUT1 alleviates ALI.

Sinensetin, a polymethoxyflavone from citrus fruits, ameliorates LPS-induced acute lung injury by suppressing Txnip/NLRP3/Caspase-1/GSDMD signaling-mediated inflammatory responses and pyroptosis.

Sinensetin (SIN), a polymethoxylated flavonoid, exists widely in citrus fruits with abundant biological activities, such as antioxidant and anti-inflammatory properties, delaying the progression of lung fibers and ameliorating inflammatory lung injury. Herein, an in vivo model of LPS-induced acute lung injury (ALI) in mice and an in vitro model of LPS + IFN-γ-induced M1 polarization in RAW264.7 cells were established to assess the effects and molecular mechanisms of SIN in ameliorating ALI. In the present study, the results showed that SIN significantly reduced BALF IL1β, IL6, and TNF-α levels and neutrophil infiltration, inhibited lung tissue COX2 and iNOS expression, reduced serum and lung tissue inflammatory factor levels, and attenuated lung tissue inflammatory infiltration and ROS levels in animal experiments. RNA sequencing analysis showed that SIN markedly inhibited the expression of inflammation-related pathway genes such as NOD-like receptor signaling. Further mechanistic studies confirmed that SIN significantly inhibited the dissociation of Txnip and Trx-1 and decreased the expression of NLRP3, ASC, pro-Caspase-1, cleavage Caspase-1 p10, NEK7, Caspase-8, IL1β, IL18, and GSDMD. Meanwhile, SIN docked to NLRP3 with strong affinity and bound stably in the hydrophobic docking pocket. Similarly, the same results were observed in in vitro macrophage M1 polarization experiments. In conclusion, the results revealed that SIN ameliorated the onset and progression of ALI by inhibiting Txnip/NLRP3/Caspase-1/GSDMD signaling-mediated inflammatory responses and pyroptosis. These findings emphasize the significant role of SIN in ameliorating ALI and provide insights into the strategy for exploring the functional effects of foods.

Predicting acute lung injury in infants with congenital heart disease after cardiopulmonary bypass by gut microbiota.

Acute lung injury (ALI) is a serious and common complication that occurs in children with congenital heart disease after cardiopulmonary bypass (CPB) surgery, leading to higher mortality rates and poorer prognosis. Currently, there is no reliable predictive strategy for CPB-associated lung injury (CPB-ALI) in infants. Certain characteristics of the gut microbiota could potentially serve as biomarkers for predicting the development of CPB-ALI. We conducted 16S rRNA sequencing to analyze the characteristics of the intestinal microbiota in healthy controls and infants with CHD admitted to the hospital. The CHD infants were divided into CPB-ALI and non-ALI (CPB-NALI) groups based on postoperative outcomes. Bacterial functional pathway prediction analysis was performed using PIRCUSt2, and the gut microbiota composition associated with immune status was determined with heatmap. Random forest regression models and ROC curves were utilized to predict the occurrence of CPB-ALI. Our study revealed significantly different microbiota compositions among three groups (CON, CPB-ALI, and CPB-NALI). The microbiota diversity was low in the CPB-ALI group with high pathogen abundance and significant decrease in Bacteroides, while the opposite was observed in the CPB-NALI group. The microbiota dysbiosis index was high in the CPB-ALI group, with its dominant microbiota significantly associated with multiple metabolic pathways. Additionally, CPB-ALI patients showed high levels of inflammatory cytokines IL-8 and HMGB1 in their serum, with high expression of IL-8 being associated with Enterobacteriaceae. Further correlation analysis showed that the differences in gut bacterial taxonomy were related to the occurrence of ALI, length of stay in the cardiac care unit, and ventilation time. It is noteworthy that Escherichia Shigella performed best in distinguishing CPB-ALI patients from non-ALI patients. Our study suggests that postoperative ALI patients have distinct gut microbiota upon admission compared to non-ALI patients after surgery. Dysbiosis of the gut microbiota may potentially impact the progression of ALI through metabolic pathways, quorum sensing, and the levels of inflammatory factors expressed in the serum. Escherichia Shigella represents a potential predictive factor for the occurrence of ALI in CHD infants after surgery. Acute lung injury, congenital heart disease, cardiopulmonary bypass surgery, gut microbiota, biomarker.

Impact of lipopolysaccharide-induced acute lung injury in aged mice

Study Aim: As the geriatric population rapidly expands, there has been a concurrent increase in elderly admissions to intensive care units (ICUs). Acute lung injury (ALI) is a prevalent reason for these admissions and carries poorer survival rates for the aged population compared to younger counterparts. The aging lung is subject to physiological, cellular, and immunological changes. However, our understanding of how aging impacts the clinical progression of ALI is limited. This study explored the effect of aging using a murine model of ALI. Methods: Female C57BL/6J mice, aged 7–8 wk (young) and 18 months (aged), were divided into four groups: young controls, aged controls, young with ALI (YL), and aged with ALI (AL). ALI was induced via intratracheal administration of lipopolysaccharide (LPS, 0.5 mg/kg). The animals were euthanized 72 h after LPS exposure. Results: The AL group exhibited a significantly increased wet/dry ratio compared to the other three groups, including the YL group. The bronchoalveolar lavage (BAL) fluid in the AL group had more cells overall, including more neutrophils, than the other groups. Inflammatory cytokines in BAL fluid showed similar trends. Histological analyses demonstrated more severe lung injury and fibrosis in the AL group than in the other groups. Increased transcription of senescence-associated secretory phenotype markers, including PAI-1 and MUC5B, was more prominent in the AL group than in the other groups. This trend was also observed in BAL samples from humans with pneumonia. Conclusions: Aging may amplify lung damage and inflammatory responses in ALI. This suggests that physicians should exercise increased caution in the clinical management of aged patients with ALI.

Dynamic evaluation of acute lung injury using hyperpolarized 129 Xe magnetic resonance.

Prognosticating acute lung injury (ALI) is challenging, in part because of a lack of sensitive biomarkers. Hyperpolarized gas magnetic resonance (MR) has unique advantages in pulmonary function measurement and can provide promising biomarkers for the assessment of lung injuries. Herein, we employ hyperpolarized 129 Xe MRI and generate a number of imaging biomarkers to detect the pulmonary physiological and morphological changes during the progression of ALI in an animal model. We find the measured ratio of 129 Xe in red blood cells to interstitial tissue/plasma (RBC/TP) is significantly lower in the ALI group on the second (0.32 ± 0.03, p = 0.004), seventh (0.23 ± 0.03, p < 0.001), and 14th (0.29 ± 0.04, p = 0.001) day after lipopolysaccharide treatment compared with that in the control group (0.41 ± 0.04). In addition, significant differences are also observed for RBC/TP measurements between the second and seventh day (p = 0.001) and between the seventh and 14th day (p = 0.018) in the ALI group after treatment. Besides RBC/TP, significant differences are also observed in the measured exchange time constant (T) on the second (p = 0.038) and seventh day (p = 0.009) and in the measured apparent diffusion coefficient (ADC) and alveolar surface-to-volume ratio (SVR) on the 14th day (ADC: p = 0.009 and SVR: p = 0.019) after treatment in the ALI group compared with that in the control group. These findings indicate that the parameters measured with 129 Xe MR can detect the dynamic changes in pulmonary structure and function in an ALI animal model.