Lung Injury In Mice Research Articles

Regulatory mechanism of TRIM21 in sepsis-induced acute lung injury by promoting IRF1 ubiquitination.

Sepsis-induced acute lung injury (ALI) is characterized by inflammatory damage to pulmonary endothelial and epithelial cells. The aim of this study is to probe the significance and mechanism of tripartite motif-containing protein 21 (TRIM21) in sepsis-induced ALI. The sepsis-induced ALI mouse model was established by cecum ligation and puncture. The mice were infected with lentivirus and treated with proteasome inhibitor MG132. The lung respiratory damage, levels of interleukin-6 (IL-6), tumour necrosis factor α (TNF-α), IL-10 and pathological changes were observed. The expression levels of TRIM21, interferon regulatory factors 1 (IRF1) and triggering receptor expressed on myeloid cells 2 (TREM2) were measured and their interactions were analysed. The ubiquitination level of IRF1 was detected. TRIM21 and TREM2 were downregulated and IRF1 was upregulated in sepsis-induced ALI mice. TRIM21 overexpression eased inflammation and lung injury. TRIM21 promoted IRF1 degradation via ubiquitination modification. IRF1 bonded to the TREM2 promoter to inhibit its transcription. Overexpression of IRF1 or silencing TREM2 reversed the improvement of TRIM21 overexpression on lung injury in mice. In conclusion, TRIM21 reduced IRF1 expression by ubiquitination to improve TREM2 expression and ameliorate sepsis-induced ALI.

Salidroside attenuates sepsis-induced acute lung injury by inhibiting ferroptosis-dependent pathway.

Sepsis triggers a systemic inflammatory response that can lead to acute lung injury (ALI). Salidroside (SAL) has many pharmacological activities such as antiinflammatory and anti-oxidation. The objective of the study was to explore the mechanism of SAL on ALI caused by sepsis. A model of ALI in septic mice was established by cecal ligation and puncture. Following SAL treatment, the effect of SAL on the ferroptosis pathway in mice was analyzed. The pathological damage of lung tissue, the levels of inflammatory factors and apoptosis in bronchoalveolar lavage fluid (BALF) of mice were evaluated, and the changes of gene expression level and metabolite content abundance were explored by combining transcriptomics and metabolomics analysis. The effect of SAL on ferroptosis in mice with lung injury was observed by intraperitoneal injection of ferroptosis activator Erastin or ferroptosis inhibitor Ferrostatin-1 to promote or inhibit ferroptosis in mice. SAL significantly alleviated the pathological damage of lung tissue, decreased the number of TUNEL positive cells and the levels of TNF-α, IL-1β, IL-6 in BALF, and increased the level of IL- 10 in lung injury mice. Moreover, the Fe2+ content and malondialdehyde decreased significantly, the reactive oxygen species and glutathione content increased significantly, and the arachidonic acid metabolites 20-hydroxyeicosatetraenoic acid (20- HETE), (5Z, 8Z, 10E, 14Z)-12-Oxoeicosa-5,8,10,14-tetraenoic acid (12-OxOETE), (5Z, 8Z, 10E, 14Z)-(12S)-12-Hydroxyeicosa-5,8,10,14-tetraenoic acid (12(S)-HETE), (5Z, 8Z, 14Z)-11,12-Dihydroxyeicosa-5,8,14-trienoic acid (11,12-DHET), (5Z, 11Z, 14Z)-8,9- Dihydroxyeicosa-5,11,14-trienoic acid, Leukotriene B4, Leukotriene D4 were significantly up-regulated after SAL treatment. Salidroside alleviates ALI caused by sepsis by inhibiting ferroptosis.

Effects of the combination of anti-PcrV antibody and bacteriophage therapy in a mouse model of Pseudomonas aeruginosa pneumonia.

Acute lung injury caused by Pseudomonas aeruginosa is attributed to the translocation of cytotoxin into pulmonary epithelial cells via the P. aeruginosa type III secretion system. This virulence can be blocked with a specific antibody against PcrV in this secretion system. However, because anti-PcrV antibodies do not have bactericidal activity, the treatment of bacteria depends on the phagocytic system of the host. In this study, we investigated the therapeutic effect of combination therapy with an anti-PcrV antibody and bactericidal bacteriophages on acute lung injury and subsequent death in mice compared with a single treatment. After the mice intratracheally received a lethal dose of the cytotoxic P. aeruginosa strain, a second instillation was performed with saline, anti-PcrV IgG, bacteriophages, or a mixture of anti-PcrV and bacteriophages. The survival rates 24 h after infection were as follows: 7.1% in the saline group, 26.7% in the anti-PcrV group, 41.2% in the phage group, and 66.7% in the anti-PcrV + phage group (P < 0.001 vs saline-treated group). The activity of surviving mice in the anti-PcrV + phage group was significantly greater than that in the saline group. The lung weight in the anti-PcrV + phage group was significantly lower than that in the anti-PcrV group. In conclusion, combination therapy with an anti-PcrV antibody and a bacteriophage reduces acute lung injury and suggests improved survival compared with each treatment alone. This combination therapy, which does not rely on conventional antibiotics, could constitute a new strategy for treating multidrug-resistant P. aeruginosa infections.IMPORTANCECombination therapy with either bacteriophages alone or in combination with anti-PcrV antibodies in a mouse model of Pseudomonas aeruginosa pneumonia may reduce the acute lung injury and improve survival. This combination therapy, which does not rely on conventional antibiotics, may be a new strategy to treat multidrug-resistant Pseudomonas aeruginosa infections.

A derivative of tanshinone IIA and salviadione, 15a, inhibits inflammation and alleviates DSS-induced colitis in mice by direct binding and inhibition of RIPK2.

Inflammatory bowel diseases (IBDs) are chronic inflammatory conditions primarily affecting the gastrointestinal tract. Previous studies established the role of the NF-κB signaling pathway in the development of IBDs, suggesting that anti-inflammatory therapies might offer a viable treatment strategy. Tanshinone IIA and salviadione, both derived from Salviae Miltiorrhizae Radix et Rhizoma, possess anti-inflammatory and anti-oxidative activities. A series of new compounds were synthesized by hybridizing salviadione with tanshinone. Among these compounds, 15a showed beneficial effects in LPS-induced acute lung injury and diabetes-induced renal injury mouse models. The current study explored the therapeutic efficacy of 15a using both acute and chronic colitis models and elucidated the underlying mechanisms. DSS-induced colitis models were established in mice, where acute colitis was treated with compound 15a (5 or 10 mg·kg-1·d-1) for 8 days, while chronic colitis mice received compound 15a (5 or 10 mg·kg-1·d-1, i.g.) during 2.5% DSS administration. The 15a treatment significantly alleviated DSS-induced pathological and inflammatory damages in both acute and chronic colitis mouse models. In mouse intestinal epithelial cell line MODE-K, pretreatment with compound 15a (5 or 10 μM) significantly suppressed LPS + L18-MDP-induced inflammatory responses. The receptor-interacting serine/threonine kinase 2 (RIPK2) was identified as a direct binding target of compound 15a using microarrays and recombinant human proteins. Moreover, 15a could directly bind to and inhibit the phosphorylation of RIPK2, leading to the suppression of the NF-κB and MAPK signaling pathways. Furthermore, LEU153 and VAL32 were identified within the KD domain of RIPK2 as critical amino residues for the binding of 15a. Briefly, the current findings demonstrate that compound 15a holds promise as a therapeutic agent for managing acute and chronic colitis.

Formulating Spray-Dried Albumin-Modified Lipid Nanoparticles Encapsulating Acyclovir for Enhanced Pulmonary Drug Delivery.

Viral pneumonia, a pressing global health issue, necessitates innovative therapeutic approaches. Acyclovir, a potent ring-opening antiviral agent with broad-spectrum activity, faces water solubility, oral bioavailability, and drug resistance challenges. The aim of this study was to increase the efficacy of acyclovir through respiratory delivery by encapsulating it within albumin-modified lipid nanoparticles and formulate it as a spray. Nanoparticles was synthesized via the reverse evaporation method; its physicochemical characteristics were rigorously evaluated, including particle size, zeta potential, morphology, encapsulation efficiency, drug loading, and release profile. Furthermore, the cytotoxicity of nanoparticles and its therapeutic potential against viral pneumonia were assessed through cellular and animal model experiments. Result s: Nanoparticles exhibited a spherical morphology, with a mean particle size of 97.48 ± 5.36 nm and a zeta potential of 30.28 ± 4.72 mv; they demonstrated high encapsulation efficiency (93.26 ± 3.27%), drug loading (11.36 ± 0.48%), and a sustained release profile of up to 92% under neutral conditions. Notably, nanoparticles showed low cytotoxicity and efficient intracellular delivery of acyclovir. In vitro studies revealed that nanoparticles significantly reduced interleukin-6 levels induced by influenza virus stimulation. In vivo, nanoparticles treatment markedly decreased mortality, attenuated the inflammatory markers interleukin-6 and tumor necrosis factor-α levels, and mitigated inflammatory lung injury in mice with viral pneumonia. In this study, albumin was modified with polyethylene glycol (PEG) containing cationic lipid nanoparticles (LN) to prepare albumin-modified lipid nanoparticles encapsulating acyclovir (ALN-Acy), which can effectively deliver Acy into tissues and cells, prolong the survival of mice, and reduce lung injury and inflammatory factors. White albumin LN can be used as efficient drug delivery carriers, and the delivery of Acy via albumin LN is expected to be a therapeutic strategy for treating inflammatory diseases.

Bergapten attenuates sepsis-induced acute lung injury in mice by regulating Th17/Treg balance

Background The abnormality of the immune system caused by infection is a contributor to the organ dysfunctions associated with sepsis. The balance between Th17/Treg cells is essential for maintaining immune homeostasis. Bergapten is a natural furocoumarin and has been reported to alleviate the Th17/Treg imbalance. Here, we explored the effects of bergapten on the inflammation and immune state in mouse models of sepsis. Methods The model was established using the cecal ligation and puncture method. Mice were administered 30 mg/kg bergapten. Histological examination, RT-qPCR, enzyme-linked immunosorbent assay, immunoblotting, immunofluorescence, immunohistochemistry, and flow cytometry were used to evaluate the effects of bergapten in vivo. Results Bergapten ameliorated lung damage, reduced lung wet/dry weight ratio, inhibited myeloperoxidase activity, and reduced inflammatory cell infiltration. Bergapten also restrained sepsis-induced inflammation via inhibition of inflammatory cytokines and NF-κB signaling. These effects were accompanied by the restored Th17/Treg balance induced by bergapten. Bergapten decreased the number of Th17 cells and elevated the number of Tregs, and this effect was mediated by the signal transducer and activator of transcription 5 (STAT5)/Forkhead box P3 (Foxp3) and STAT3/retinoid-related orphan receptor-γt (RORγt) pathways. Conclusions Bergapten exerted anti-inflammatory effects in acute lung injury by improving the Th17/Treg balance, which suggested a potential of bergapten as an immunomodulatory drug treating sepsis-associated diseases.

Optimized administration of human embryonic stem cell-derived immunity-and-matrix regulatory cells for mouse lung injury and fibrosis

BackgroundLung injury and pulmonary fibrosis (PF), frequently arising as sequelae of severe and acute lung disease, currently face a dearth of effective therapeutic potions. Mesenchymal stem cells (MSCs) with immunomodulatory and tissue repair functions have immense potential to treat lung injury and PF. However, the optimal route of administration, timing, and frequency of dosing remain elusive. Human embryonic stem cell-derived immunity-and-matrix-regulatory cells (IMRCs) have shown therapeutic potential for lung injury and PF.MethodsTo ascertain the optimal therapeutic regimen for IMRCs in PF, we conducted an experimental study. Utilizing a mouse model of PF induced by bleomycin (BLM), IMRCs were administered via either a single or double intravenous (IV) or intratracheal (IT) injection on the first and seventh days post-BLM induction.ResultsOur findings revealed that IV infusion of IMRCs surpassed IT infusion in enhancing survival rates, facilitating body weight recovery, and optimizing Ashcroft and Szapiel scores among the model mice. Notably, IV administration exhibited a more profound ability to mitigate lung inflammation and fibrosis. Moreover, earlier and more frequent administrations of IMRCs were found to be advantageous in enhancing their therapeutic effects. Specifically, early administration with two IV infusions significantly improved body weight, lung organ coefficient, pulmonary ventilation and diffusion functions, and PF. This was accompanied by an increase in alveolar type I and II epithelial cells and a suppression of macrophage infiltration via CD24.ConclusionCollectively, these results suggested that IMRCs infusion ameliorated lung injury by promoting lung regeneration and inhibiting macrophage infiltration in a route, time, and frequency-dependent manner.

Ozone-Induced Lung Injury are Mediated Via PPAR-Mediated Ferroptosis in Mice.

In recent years, the concentration of PM2.5 in China has decreased, while the concentration of ozone remains rising. Exposure to ozone contributes to respiratory illnesses; however, little is known about the underlying molecular mechanisms. The present study established an ozone-induced lung injury mice model to investigate potential molecular biomarkers and toxic mechanisms. Collected and analyzed the ozone pollution data in Xinxiang city from 2015 to 2022. At the same time, 24 male C57BL/6 mice were randomly assigned to control group and ozone exposure group. The ozone exposure concentration is 1ppm, with 4h of daily exposure for 33 consecutive days. HE staining was used to assess lung histological alterations and lung injury. High-throughput sequencing performed on the lung tissues of mice was used to analyze the differential expressed genes and signal transduction pathways. Xinxiang city is suffering from ozone pollution, especially in summer. HE staining showed that the ozone exposure could induce obvious inflammatory cell infiltration, alveolar wall thickening, or fracture. Transcriptome data revealed that there is a 145 differentially expressed genes between two groups and the genes enriched in PPAR signaling pathway, ferroptosis. The pivotal genes in the PPAR pathway including Adipoq, Lpl, Pck1, and Plin1 expression were significantly reduced. Additionally, the expression of Acsl6 and Scl7a11, which are close to PPAR pathway and ferroptosis has decreased. Ozone exposure could disrupt the lipid metabolism balance via downregulating lipid peroxidation-related genes through the PPAR signaling pathway, which further induced lung cell ferroptosis and aggravated lung injury in mice.

The Thyroid Hormone Analog GC-1 Mitigates Acute Lung Injury by Inhibiting M1 Macrophage Polarization.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a life-threatening condition with a high mortality rate of ≈40%. Thyroid hormones (THs) play crucial roles in maintaining homeostasis of the cellular microenvironment under stress. The previous studies confirmed that the clinical-stage TH analog GC-1 significantly alleviates pulmonary fibrosis by improving the function of mitochondria in epithelial cells. However, the effects of GC-1 on macrophages in lung injury and the related mechanisms remain unclear. This study evaluated the therapeutic effects of GC-1 in two murine models of lipopolysaccharide (LPS)- or hydrochloric acid (HCl)-induced ALI. Additionally, mouse alveolar macrophages (AMs) and human THP-1-derived macrophages are utilized to investigate the impact of GC-1 on macrophage polarization. GC-1 effectively reduces the inflammatory response and lung injury in ALI mice, as evidenced by neutrophil infiltration, cytokine levels, alveolar fluid clearance, and pulmonary pathology. Notably, GC-1 selectively inhibits M1 macrophage polarization, which may be achieved by impeding NF-κB signaling activation through the DNMT3b-PPARγ-NF-κB pathway in a TH receptor β1 (TRβ1)-dependent manner, consequently suppressing the polarization of macrophages toward the M1 phenotype and overproduction of inflammatory cytokines. Overall, these findings highlight the immunomodulatory property of GC-1 as an anti-inflammatory strategy for ALI/ARDS and inflammation-related diseases.

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.

Multi-immunometabolomics mining: NP prevents hyperimmune in ALI by inhibiting Leucine/PI3K/Akt/mTOR signaling pathway

Acute lung injury (ALI) is currently a global health concern. Nicandra physalodes (L.) Gaertn. (NP) holds an important position in traditional Chinese medicine and nutrition. The potential protective mechanisms of NP against ALI remain unknown. The purpose of this study was to investigate the protective effects and molecular mechanisms of NP extract (NPE) on lipopolysaccharide (LPS)-induced ALI in mice. By utilizing network pharmacology to forecast the active ingredients in NP as well as possible signaling pathways. The composition of the NPE was analyzed using UPLC-Q-TOF-MS/MS. In addition, 1H-NMR immunometabolomics was employed to identify alterations in primary metabolic pathways and metabolites in the lung, serum, and fecal tissues. Finally, the protein and gene expression of key pathways were verified by IHC, IF, RT-qPCR, and ELISA. It was found that the main ingredients of NPE were revealed to be nicandrenone, withanolide A, and baicalin. NPE significantly improved lung injury, pulmonary edema, and inflammatory cell infiltration in mice with ALI. In addition, NPE improved autophagic activity and alleviated Th1 and Th17 cell-induced lung inflammation by suppressing the PI3K/Akt/mTOR signaling pathway. Importantly, immunometabolomic analysis of fecal, serum, and lung tissues revealed that NPE reversed ALI-induced leucine resistance by remodeling immunometabolism. We confirmed NPE prevents ALI by remodeling immunometabolism, regulating the Leucine/PI3K/Akt/mTOR signaling pathway, inhibiting Th1/Th17 cell differentiation, and providing a scientific immunological basis for the clinical application of NPE.

Screening the effective components of Lysionotus pauciflorus Maxim. on the treatment of LPS induced acute lung injury mice by integrated UHPLC-Q-TOF-MS/MS and network pharmacology

Ethnopharmacological relevanceAcute lung injury (ALI) is an inflammatory reaction produced through various injury-causing factors acting on the lungs in a direct or indirect way, with a high morbidity and mortality rate. A review of clinical experience has revealed that Lysionotus pauciflorus Maxim (LP) has a significant therapeutic effect on ALI. However, the comprehensive effective components of LP are uncertain, and the mechanisms, especially the potential therapeutic target for anti-ALI, are still unknown. Aims of the studyIn vitro and in vivo validation of the pharmacodynamics of LP in the treatment of ALI and exploration of its potential mechanism of action based on network pharmacology, molecular docking and experimental validation. Materials and methodsUltra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was employed to identify the ingredients of LP extracts. The potential bioactive ingredients, key targets and signalling pathways were identified by network pharmacology, based on the results of the mass spectrometry analysis. Subsequently, molecular docking was performed on the screened core components and key targets to calculate their molecular binding energies and binding potentials, and to explore the mutual binding modes of small-molecule ligands and large-molecule proteins. Finally, lipopolysaccharide (LPS)-induced RAW264.7 cell model and ALI mice model were used to validate the therapeutic effects and potential mechanism of LP extract towards ALI. ResultsFrom the mass spectrometry results of LP extracts, a total of 89 chemical components were identified, including 46 phenylethanol glycosides, 26 flavonoids, 9 organic acids and their derivatives and 8 other compounds. And furthermore 39 core active components were screened by network pharmacology. The top 10 core components (4 phenylethanol glycosides, 6 flavonoids) have been screened in the composition -target-disease network, and 37 core targets related to LP efficacy were obtained by fitting PPI network analysis. 10 signalling pathways and their targets associated with LP treatment of ALI were obtained by GO/KEGG analysis, indicating that LP could regulate TLR4 and NF-κB signalling pathways through 4 key targets, namely NFKB1, RELA, TLR4 and TNF. The results of the molecular docking procedure indicated a strong affinity, with the binding energies between each component and the target site being less than −6 kcal/mol. The binding modes included Hydrogen Bonds, Pi-Pi interaction, Hydrophobic Interactions, Salt Bridges, Pi-cation interactions. These observations were subsequently validated in vitro and in vivo experiments. The outcomes of in vitro and in vivo experiments demonstrated that LP was effective in reducing the infiltration of inflammatory bacteria in lung tissues and attenuated the expression of pro-inflammatory cytokines in LPS-stimulated mice bronchoalveolar lavage fluid (BALF) and RAW264.7 cells. Furthermore, LP inhibited the expression and phosphorylation of TLR4 protein and NF-κB protein, thus playing a role in the prevention of ALI. ConclusionsIn this study, mass spectrometry analysis was combined with biomolecular networks to initially elucidate the potential of LP to treat ALI by modulating the TLR4/NF-κB pathway. This offers a definitive experimental basis for the development of new LP drugs.

Fibroblast growth factor 21 attenuates pulmonary ischemia/reperfusion injury via inhibiting endoplasmic reticulum stress-induced ferroptosis though FGFR1/PPARδ signaling pathway

BackgroundAcute lung injury is a critical life-threatening complication of pulmonary and cardiac surgery with a high rate of morbidity and mortality. Fibroblast growth factor 21 (FGF21) has been reported to play an important role in protecting vital organs from damage. This study aims to investigate the potential protective role and mechanism of FGF21 in pulmonary ischemia/reperfusion (I/R)-induced acute lung injury. MethodsA pulmonary epithelial cell line was treated with hypoxia/regeneration (H/R) in vitro and a mouse model of acute lung injury was induced with pulmonary I/R in vivo. Lung injury after pulmonary I/R was compared between FGF21-konckout (KO) mice and wild-type (WT) mice. Recombinant FGF21 was administrated in vivo and in vitro to determine its therapeutic effect. ResultsCirculating levels of FGF21 in mice with pulmonary I/R injury were significantly higher than in those without pulmonary I/R injury. Lung injury was aggravated in FGF21-KO mice compared with WT mice and the administration of FGF21 alleviated lung injury in mouse treated with I/R and pulmonary epithelial cell injury treated with H/R. FGF21 treatment decreased endoplasmic reticulum (ER) stress, Fe2+ and lipid reactive oxygen species (ROS) contents and GPX4 expression and increased PTGS2 levels. Mechanistically, FGF21 upregulated the expression of FGFR1 and PPARδ, ameliorated ER stress and ER stress induced-ferroptosis. Furthermore, FGF21 increased the expression level of PPARδ in pulmonary epithelial cell exposed to H/R, which was inhibited by FGFR1 inhibitor (PD173074). The protective effects of FGF21 were abolished by co-treatment with PPARδ inhibitor (GSK0660), indicating FGF21 attenuated ER stress-induced ferroptosis by dependent on FGFR1/PPARδ signaling pathway. ConclusionOur study reveals that FGF21 protects against pulmonary I/R injury via inhibiting ER stress-induced ferroptosis though FGFR1/PPARδ signaling pathway. Boosting endogenous FGF21 or the administration of recombinant FGF21 could be promising therapeutic strategies for pulmonary IRI.

Lipid peroxidation triggered by the degradation of xCT contributes to gasdermin D-mediated pyroptosis in COPD

BackgroundPyroptosis is an inflammatory form of regulated necrosis that has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the role of lipid peroxidation in pyroptosis and its underlying mechanisms in COPD remain unclear. MethodsIn vitro, human bronchial epithelial cells (Beas-2b cells) were exposed to cigarette smoke extract (CSE) for 24 h. In vivo, mice were exposed to cigarette smoke (CS) for 4 weeks. To investigate the role of xCT, we used siRNA and AAV6 to conditionally knock down xCT in vitro and in vivo, respectively. ResultsThe administration of ferrostatin-1 (Fer-1), a ferroptosis inhibitor that inhibits lipid peroxidation, significantly reduced the cytotoxicity of CSE to Beas-2b cells and mitigated inflammatory exudation, lung injury and mucus hypersecretion in mice with CS-induced COPD. Fer-1 suppressed gasdermin D (GSDMD)-mediated pyroptosis caused by CS in vitro and in vivo. However, in Beas-2b cells and the lung epithelial cells of mice, conditional knockdown of xCT (a negative regulatory factor of lipid peroxidation) inhibited the xCT/GPx4 axis, leading to more severe lipid peroxidation and GSDMD-mediated pyroptosis during cigarette smoke exposure. Moreover, we found that CS promoted the degradation of xCT through the ubiquitin proteasome system (UPS) and that treatment with MG132 significantly inhibited the degradation of xCT and downregulated the expression of pyroptosis-related proteins. ConclusionThe results of this study suggested that the ubiquitination-mediated degradation of xCT drives GSDMD-mediated pyroptosis in COPD and is a potential therapeutic target for COPD.

Discovery of a novel AhR–CYP1A1 axis activator for mitigating inflammatory diseases using an in situ functional imaging assay

The aryl hydrocarbon receptor (AhR) plays a crucial role in regulating many physiological processes. Activating the AhR–CYP1A1 axis has emerged as a novel therapeutic strategy against various inflammatory diseases. Here, a practical in situ cell-based fluorometric assay was constructed to screen AhR-CYP1A1 axis modulators, via functional sensing of CYP1A1 activities in live cells. Firstly, a cell-permeable, isoform-specific enzyme-activable fluorogenic substrate for CYP1A1 was rationally constructed for in-situ visualizing the dynamic changes of CYP1A1 function in living systems, which was subsequently used for discovering the efficacious modulators of the AhR–CYP1A1 axis. Following screening of a compound library, LAC-7 was identified as an efficacious activator of the AhR–CYP1A1 axis, which dose-dependently up-regulated the expression levels of both CYP1A1 and AhR in multiple cell lines. LAC-7 also suppressed macrophage M1 polarization and reduced the levels of inflammatory factors in LPS-induced bone marrow-derived macrophages. Animal tests showed that LAC-7 could significantly mitigate DSS-induced ulcerative colitis and LPS-induced acute lung injury in mice, and markedly reduced the levels of multiple inflammatory factors. Collectively, an optimized fluorometric cell-based assay was devised for in situ functional imaging of CYP1A1 activities in living systems, which strongly facilitated the discovery of efficacious modulators of the AhR–CYP1A1 axis as novel anti-inflammatory agents.

Effects of tryptophan on lipopolysaccharide-induced acute lung injury in colitis mice

Effects of tryptophan on lipopolysaccharide-induced acute lung injury in colitis mice

Epigenetic mechanism of EZH2-mediated histone methylation modification in regulating ferroptosis of alveolar epithelial cells in sepsis-induced acute lung injury.

Sepsis-induced acute lung injury (SI-ALI) leads to significant deaths in critically ill patients worldwide. This study explores the mechanism of EZH2 regulating ferroptosis of alveolar epithelial cells (AECs) in SI-ALI. In vitro cell model and in vivo mouse lung injury model of sepsis were established. EZH2 expression in lung tissues was intervened by sh-EZH2, followed by H&E staining observation of lung tissue pathological changes. EZH2, H3K27me3, USP10, GPX4, and ACSL4 expressions were determined by qRT-PCR or Western blot. ROS, GSH, and iron ion levels were detected using fluorescent labeling and reagent kits, respectively. ChIP analyzed the enrichment of EZH2 and H3K27me3 on USP10 promoter. The binding between USP10 and GPX4, and the ubiquitination level of GPX4 were detected using Co-IP. EZH2 was highly expressed in lung tissues of SI-ALI mice. EZH2 silencing alleviated ALI and ferroptosis of AECs; EZH2 increased the H3K27me3 level on USP10 promoter through histone methylation. USP10 stabilized GPX4 protein expression through ubiquitination; inhibition of USP10 partially reversed the inhibitory effect of EZH2 silencing on ferroptosis of AECs. In conclusion, EZH2 depresses USP10 expression by promoting histone H3K27me3 modification on USP10 promoter, thereby enhancing ubiquitination degradation of GPX4 and ultimately facilitating ferroptosis of AECs in sepsis.

Machine learning for automated classification of lung collagen in a urethane-induced lung injury mouse model.

Dysregulation of lung tissue collagen level plays a vital role in understanding how lung diseases progress. However, traditional scoring methods rely on manual histopathological examination introducing subjectivity and inconsistency into the assessment process. These methods are further hampered by inter-observer variability, lack of quantification, and their time-consuming nature. To mitigate these drawbacks, we propose a machine learning-driven framework for automated scoring of lung collagen content. Our study begins with the collection of a lung slide image dataset from adult female mice using second harmonic generation (SHG) microscopy. In our proposed approach, first, we manually extracted features based on the 46 statistical parameters of fibrillar collagen. Subsequently, we pre-processed the images and utilized a pre-trained VGG16 model to uncover hidden features from pre-processed images. We then combined both image and statistical features to train various machine learning and deep neural network models for classification tasks. We employed advanced unsupervised techniques like K-means, principal component analysis (PCA), t-distributed stochastic neighbour embedding (t-SNE), and uniform manifold approximation and projection (UMAP) to conduct thorough image analysis for lung collagen content. Also, the evaluation of the trained models using the collagen data includes both binary and multi-label classification to predict lung cancer in a urethane-induced mouse model. Experimental validation of our proposed approach demonstrates promising results. We obtained an average accuracy of 83% and an area under the receiver operating characteristic curve (ROC AUC) values of 0.96 through the use of a support vector machine (SVM) model for binary categorization tasks. For multi-label classification tasks, to quantify the structural alteration of collagen, we attained an average accuracy of 73% and ROC AUC values of 1.0, 0.38, 0.95, and 0.86 for control, baseline, treatment_1, and treatment_2 groups, respectively. Our findings provide significant potential for enhancing diagnostic accuracy, understanding disease mechanisms, and improving clinical practice using machine learning and deep learning models.

Intratracheal delivery of macrophage targeted Celastrol-loaded PLGA nanoparticles for enhanced anti-inflammatory efficacy in acute lung injury mice

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common causes of respiratory failure in critically ill patients. There is still a lack of definitive and effective treatment options, and the mortality rate remains as high as 30% to 40%. Effective therapeutics for ALI/ARDS are greatly hindered by the side effects resulting from inefficient delivery to the disease lesions and off-targeting biodistribution of drugs. Macrophages play an integral role in maintaining the steady state of the immune system and are involved in inflammation processes. Thus, nanodrug to accurately target macrophages have the potential to transform disease treatment. Here, we developed an mannosylated drug delivery system to target and deliver celastrol (Cel) to the alveolar macrophages for enhanced alleviating the cytokines in LPS-induce ALI mice. In vitro data demonstrated that the as-synthesized Man@Cel-NPs significantly improved the targeting of Cel into the inflammatory macrophages via mannose receptor-mediated phagocytosis. In vivo experiments further showed that intratracheal delivery of Man@Cel-NPs can improve the dysregulation of inflammatory response in LPS-induced mice by inhibiting the release of inflammatory cytokines and increasing autophagy and decreasing apoptosis in lungs. This work provides a potential NP platform for the locally tracheal delivery of herbal ingredients and exhibits promising clinical potential in the treatment of numerous respiratory diseases, including ALI/ARDS.

Curcumin alleviates septic lung injury in mice by inhibiting TXNIP/TRX-1/GPX4-mediated ferroptosis

To investigate whether curcumin alleviates septic lung injury by inhibiting ferroptosis through modulating the TXNIP/TRX-1/GPX4 pathway. Male C57BL/6 mice were randomly divided into Sham group, cecal ligation puncture (CLP)-induced sepsis group, CLP with curcumin treatment (50, 100, and 200 mg/kg) groups, and CLP with both curcumin (200 mg/kg) and TRX-1 inhibitor PX-12 (25 mg/kg) treatment group. Inflammatory factors, MDA, MPO, and GSH levels in the lung tissue of the mice were detected. Beas-2B cells stimulated with lipopolysaccharide (LPS; 1 μg/mL) were treated with 2.5, 5, or 10 μmol/L curcumin or with 10 μmol/L curcumin combined with 5 μmol/L PX-12, and the changes in MDA, Fe2+ and ROS levels were assessed. Western blotting was performed to detect the protein expressions of TXNIP, TRX-1, GPX4 and X-CT in both the mouse lung tissues and Beas-2B cells. The mice with CLP-induced sepsis showed severe lung injury with elevated expressions of IL-6, IL-1β, TNF-α, MDA and MPO and decreased GSH expression. In Beas-2B cells, LPS stimulation significantly increased MDA and Fe2+ levels and ROS release, increased TXNIP protein expression, and lowered the protein expression levels of TRX-1, GPX4 and X-CT, and these changes were also observed in the septic mice. Curcumin treatments at different concentrations obviously alleviated lung injury in the septic mice and reduced LPS-induced injury in Beas-2B cells. Curcumin significantly decreased the release of inflammatory factors, MDA and MPO, increased GSH level, lowered Fe2+, MDA and ROS levels, increased TXNIP protein expression, and lowered the protein expressions of TRX-1, GPX4 and X-CT in both septic mouse lung tissues and LPS-stimulated Beas-2B cells. The protective effect of curcumin was effectively blocked by PX-12 treatment. Curcumin inhibits ferroptosis and alleviates septic lung injury in mice by elevating TRX-1 and GPX4 and decreasing TXNIP in the lung tissue.