Sepsis-induced Acute Lung Injury Research Articles

Wogonin alleviates sepsis-induced acute lung injury by modulating macrophage polarization through the SIRT1-FOXO1 pathways

Wogonin alleviates sepsis-induced acute lung injury by modulating macrophage polarization through the SIRT1-FOXO1 pathways

Bilirubin Nanoparticles Alleviate Sepsis-Induced Acute Lung Injury by Protecting Pulmonary Endothelia Glycocalyx and Reducing Inflammation

Bilirubin Nanoparticles Alleviate Sepsis-Induced Acute Lung Injury by Protecting Pulmonary Endothelia Glycocalyx and Reducing Inflammation

Danlou tablet alleviates sepsis-induced acute lung and kidney injury by inhibiting the PARP1/HMGB1 pathway

BackgroundSepsis-associated acute lung injury (ALI) and acute kidney injury (AKI) are common complications that significantly impact patient prognosis. Danlou tablet (DLT) is a traditional herbal preparation with anti-inflammatory and antioxidant properties. However, its therapeutic potential in sepsis remains unknown. MethodsThe impact of DLT on ALI and AKI was evaluated using the cecal ligation and puncture (CLP) experimental sepsis animal model. The effects of DLT on macrophages were observed through LPS-stimulated RAW264.7 cell line. Inflammatory cytokines, oxidative stress indicators, HE, PAS, and DHE staining, lung wet-to-dry weight ratio, and serum creatinine and urea nitrogen levels were used to assess tissue injury. Network pharmacology, molecular docking, and molecular dynamics simulations were used to explore the potential regulatory mechanisms of DLT in sepsis. Western blot and immunohistochemical staining were used to validate the expression of mechanism-related proteins. ResultsDLT inhibited the inflammatory response and oxidative stress, improved structural and functional abnormalities in lung and kidney tissues in CLP mice, and alleviated pro-inflammatory responses of LPS-stimulated macrophages. PARP1 and HMGB1 were identified as key regulatory targets. The results of in vitro and in vivo experiments suggest that DLT can effectively inhibit PARP1/HMGB1 and improve sepsis-associated ALI and AKI. ConclusionThe present study demonstrated that DLT suppressed pro-inflammatory responses of macrophage and alleviated ALI and AKI in the CLP mice by inhibiting the transition activation of PARP1/HMGB1. These findings partially elucidate the mechanism of DLT in sepsis-associated ALI and AKI and further clarify the active components of DLT, thereby providing a scientific theoretical basis for treating sepsis with DLT.

Crtc1 deficiency protects against sepsis-associated acute lung injury through activating akt signaling pathway

BackgroundInterplay between systemic inflammation and programmed cell death contributes to the pathogenesis of acute lung injury (ALI). cAMP-regulated transcriptional coactivator 1 (CRTC1) has been involved in the normal function of the pulmonary system, but its role in ALI remains unclear.Methods and resultsWe generated a Crtc1 knockout (KO; Crtc1−/−) mouse line. Sepsis-induced ALI was established by cecal ligation and puncture (CLP) for 24 h. The data showed that Ctrc1 KO substantially ameliorated CLP-induced ALI phenotypes, including improved lung structure destruction, reduced pulmonary vascular permeability, diminished levels of proinflammatory cytokines and chemokines, compared with the wildtype mice. Consistently, in lipopolysaccharide (LPS)-treated RAW264.7 cells, Crtc1 knockdown significantly inhibited the expression of inflammatory effectors, including TNF-α, IL-1β, IL-6 and CXCL1, whereas their expressions were significantly enhanced by Crtc1 overexpression. Moreover, both Crtc1 KO in mice and its knockdown in RAW264.7 cells dramatically reduced TUNEL-positive cells and the expression of pro-apoptotic proteins. In contrast, Crtc1 overexpression led to an increase in the pro-apoptotic proteins and LPS-induced TUNEL-positive cells. Mechanically, we found that the phosphorylation of Akt was significantly enhanced by Crtc1 knockout or knockdown, but suppressed by Crtc1 overexpression. Administration of Triciribine, an Akt inhibitor, substantially blocked the protection of Crtc1 knockdown on LPS-induced inflammation and cell death in RAW264.7 cells.ConclusionsOur study demonstrates that CRTC1 contribute to the pathological processes of inflammation and apoptosis in sepsis-induced ALI, and provides mechanistic insights into the molecular function of CRTC1 in the lung. Targeting CRTC1 would be a promising strategy to treat sepsis-induced ALI in clinic.

Association between high-flow nasal cannula use and mortality in patients with sepsis-induced acute lung injury: a retrospective propensity score-matched cohort study

BackgroundHigh-flow nasal cannula (HFNC) has emerged as a promising noninvasive method for delivering oxygen to critically ill patients, particularly those with sepsis and acute lung injury. However, uncertainties persist regarding its therapeutic benefits in this specific patient population.MethodsThis retrospective study utilized a propensity score-matched cohort from the Medical Information Mart in Intensive Care-IV (MIMIC-IV) database to explore the correlation between HFNC utilization and mortality in patients with sepsis-induced acute lung injury. The primary outcome was 28-day all-cause mortality.ResultsIn the propensity score-matched cohort, the 28-day all-cause mortality rate was 18.63% (95 out of 510) in the HFNC use group, compared to 31.18% (159 out of 510) in the non-HFNC group. The use of HFNC was associated with a lower 28-day all-cause mortality rate (hazard ratio [HR] = 0.53; 95% confidence interval [CI] = 0.41–0.69; P < 0.001). HFNC use was also associated with lower ICU mortality (odds ratio [OR] = 0.52; 95% CI = 0.38–0.71; P < 0.001) and lower in-hospital mortality (OR = 0.51; 95% CI = 0.38–0.68; P < 0.001). Additionally, HFNC use was found to be associated with a statistically significant increase in both the ICU and overall hospitalization length.ConclusionsThese findings indicate that HFNC may be beneficial for reducing mortality rates among sepsis-induced acute lung injury patients; however, it is also associated with longer hospital stays.

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.

Preventive Effect of the Total Polyphenols from Nymphaea candida on Sepsis-Induced Acute Lung Injury in Mice via Gut Microbiota and NLRP3, TLR-4/NF-κB Pathway.

This study aimed to investigate the preventive effects of the total polyphenols from Nymphaea candida (NCTP) on LPS-induced septic acute lung injury (ALI) in mice and its mechanisms. NCTP could significantly ameliorate LPS-induced lung tissue pathological injury in mice as well as lung wet/dry ratio and MPO activities (p < 0.05). NCTP could significantly decrease the blood leukocyte, neutrophil, monocyte, basophil, and eosinophil amounts and LPS contents in ALI mice compared with the model group (p < 0.05), improving lymphocyte amounts (p < 0.05). Moreover, compared with the model group, NCTP could decrease lung tissue TNF-α, IL-6, and IL-1β levels (p < 0.05) and downregulate the protein expression of TLR4, MyD88, TRAF6, IKKβ, IκB-α, p-IκB-α, NF-κB p65, p-NF-κB p65, NLRP3, ASC, and Caspase1 in lung tissues (p < 0.05). Furthermore, NCTP could inhibit ileum histopathological injuries, restoring the ileum tight junctions by increasing the expression of ZO-1 and occludin. Simultaneously, NCTP could reverse the gut microbiota disorder, restore the diversity of gut microbiota, increase the relative abundance of Clostridiales and Lachnospiraceae, and enhance the content of SCFAs (acetic acid, propionic acid, and butyric acid) in feces. These results suggested that NCTP has preventive effects on septic ALI, and its mechanism is related to the regulation of gut microbiota, SCFA metabolism, and the TLR-4/NF-κB and NLRP3 pathways.

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.

Mechanisms of Sepsis-Induced Acute Lung Injury and Advancements of Natural Small Molecules in Its Treatment.

Sepsis-induced acute lung injury (ALI), characterized by widespread lung dysfunction, is associated with significant morbidity and mortality due to the lack of effective pharmacological treatments available clinically. Small-molecule compounds derived from natural products represent an innovative source and have demonstrated therapeutic potential against sepsis-induced ALI. These natural small molecules may provide a promising alternative treatment option for sepsis-induced ALI. This review aims to summarize the pathogenesis of sepsis and potential therapeutic targets. It assembles critical updates (from 2014 to 2024) on natural small molecules with therapeutic potential against sepsis-induced ALI, detailing their sources, structures, effects, and mechanisms of action.

Protective effects of Wenqingyin on sepsis-induced acute lung injury through regulation of the receptor for advanced glycation end products pathway

BackgroundWenqingyin (WQY), an ancient Chinese medicinal agent, has been extensively used in treating infectious ailments throughout history. However, the anti-sepsis mechanism remains unknown. PurposeThis study investigated the diverse mechanisms of WQY in mitigating sepsis-induced acute lung injury (ALI). Additionally, the effects of WQY were validated using biological experiments. MethodsThis study combined UHPLC-Orbitrap-HRMS analysis and network pharmacology to predict the potential anti-sepsis mechanism of WQY. Sepsis-induced ALI models were established in vivo via intraperitoneal lipopolysaccharide (LPS) administration and in vitro by LPS-stimulated RAW 264.7 macrophages. Various techniques, including hematoxylin-eosin staining, TUNEL, qPCR, and ELISA, were used to assess lung damage and quantify inflammatory cytokines. Inflammatory cell infiltration was visualized through immunohistochemistry. Hub targets and signaling pathways were identified using Western blotting, immunohistochemistry, and immunofluorescence staining. ResultsSeventy-five active components and 237 associated targets were acquired, with 145 of these targets overlapping with processes related to sepsis. Based on the comprehensive protein-protein interaction network analysis, JUN, AKT1, TP53, IL-6, HSP90AA1, CASP3, VEGFA, IL-1β, RELA, and EGFR may be targets of WQY for sepsis. Analysis of the Kyoto Gene and Genome Encyclopedia revealed that WQY is implicated in the advanced glycation end products/receptor for advanced glycation end products (AGE/RAGE) signaling pathway. In vivo, WQY alleviated sepsis-induced ALI, suppressing proinflammatory cytokines and inhibiting macrophage/neutrophil infiltration. In vitro, WQY reduced TNF-α, IL-6, and IL-1β in LPS-induced RAW 264.7 macrophages. Furthermore, we verified that WQY protected against sepsis-induced ALI by regulating the RAGE pathway for the first time. Baicalin, coptisine, and paeoniflorin may be the effective components of WQY that inhibit RAGE. ConclusionThe primary mechanism of WQY in combating sepsis-induced ALI involves controlling RAGE levels and the PI3K/AKT pathway, suppressing inflammation, and mitigating lung damage. This study establishes a scientific foundation for understanding the mechanism of WQY and its clinical use in treating sepsis.

Associations of Inflammation, Oxidative Stress and Prognosis with IL-37 Expression in Sepsis Rats with Lung Injury

This study aimed to investigate the role of interleukin-37 (IL-37) expression in lung tissues of sepsis-induced acute lung injury (ALI) rats and its impact on ALI, along with the underlying mechanisms. Sprague-Dawley (SD) rats were categorized into three groups: Control, sepsis-induced ALI (via cecal ligation and puncture, CLP), and sepsis-induced ALI with antibiotics (CLP+An). ALI models were established, and lung tissue injuries were assessed through hematoxylineosin staining. mRNA levels of IL-1α, IL-1β, IL-37, and tumor necrosis factor-α (TNF-α) were measured via RT-PCR, while IL-37 protein levels in lung tissues were determined using Western blotting. Additionally, bronchoalveolar lavage fluid (BALF) and blood samples were collected to assess inflammatory factors through ELISA. In the CLP group, there was an increase in pro-inflammatory factors (IL-1α, IL-1β, and TNF-α) in lung tissues and serum. However, in the CLP+An group, these factors decreased, IL-37 expression increased, and oxidative stress levels decreased. IL-37 demonstrated an inhibitory effect on the release of pro-inflammatory factors (IL-1α, IL-1β, and TNF-α) in sepsis rats, leading to a reduction in lung tissue inflammation. Furthermore, IL-37 exhibited a protective role by reducing oxidative stress in sepsis-induced lung tissues. These findings highlight IL-37 as a potential therapeutic target for mitigating ALI in sepsis.

S100A9 exacerbates sepsis-induced acute lung injury via the IL17-NFκB-caspase-3 signaling pathway

BackgroundSepsis-induced acute lung injury (ALI) is associated with considerable morbidity and mortality in critically ill patients. S100A9, a key endothelial injury factor, is markedly upregulated in sepsis-induced ALI; however, its specific mechanism of action has not been fully elucidated. MethodsThe Gene Expression Omnibus database transcriptome data for sepsis-induced ALI were used to screen for key differentially expressed genes (DEGs). Using bioinformatics analysis methods such as Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein-protein interaction network analyses, the pathogenesis of sepsis-induced ALI was revealed. Intratracheal infusion of lipopolysaccharide (LPS, 10 mg/kg) induced ALI in wild-type (WT) and S100A9 knockout mice. Multiomics analyses (transcriptomics and proteomics) were performed to investigate the potential mechanisms by which S100A9 exacerbates acute lung damage. Hematoxylin-eosin, Giemsa, and TUNEL staining were used to evaluate lung injury and cell apoptosis. LPS (10 μg/mL)-induced murine lung epithelial MLE-12 cells were utilized to mimic ALI and were modulated by S100A9 lentiviral transfection. The impact of S100A9 on cell apoptosis and inflammatory responses were identified using flow cytometry and PCR. The expression of interleukin (IL)-17–nuclear factor kappa B (NFκB)–caspase-3 signaling components was identified using western blotting. ResultsSix common DEGs (S100A9, S100A8, IFITM6, SAA3, CD177, and MMP9) were identified in the six datasets related to ALI in sepsis. Compared to WT sepsis mice, S100A9 knockout significantly alleviated LPS-induced ALI in mice, with reduced lung structural damage and inflammatory exudation, decreased exfoliated cell and protein content in the lung lavage fluid, and reduced apoptosis and necrosis of pulmonary epithelial cells. Transcriptomic analysis revealed that knocking out S100A9 significantly affected 123 DEGs, which were enriched in immune responses, defense responses against bacteria or lipopolysaccharides, cytokine-cytokine receptor interactions, and the IL-17 signaling pathway. Proteomic analysis revealed that S100A9 knockout alleviated muscle contraction dysfunction and structural remodeling in sepsis-induced ALI. Multiomics analysis revealed that S100A9 may be closely related to interferon-induced proteins with tetratricopeptide repeats and oligoadenylate synthase-like proteins. LPS decreased MLE12 cell activity, accompanied by high expression of S100A9. The expression of IL-17RA, pNFκB, and cleaved-caspase-3 were increased by S100A9 overexpression and reduced by S100A9 knockdown in LPS-stimulated MLE12 cells. S100A9 knockdown decreases transcription of apoptosis-related markers Bax, Bcl and caspase-3, alleviating LPS-induced apoptosis. ConclusionsS100A9 as a key biomarker of sepsis-induced acute lung injury, and exacerbates lung damage and epithelial cell apoptosis induced by LPS via the IL-17–NFκB–caspase-3 signaling pathway.

Integrating UPLC-Q-Orbitrap MS with serum pharmacochemistry network and experimental verification to explore the pharmacological mechanisms of Cynanchi stauntonii rhizoma et radix against sepsis-induced acute lung injury.

Introduction: Patients with sepsis are at an incremental risk of acute lung injury (ALI). Baiqian, also known as Cynanchi stauntonii rhizoma et radix (Csrer), has anti-inflammatory properties and is traditionally used to treat cough and phlegm. This study aimed to demonstrate the multicomponent, multitarget, and multi-pathway regulatory molecular mechanisms of Csrer in treating lipopolysaccharide (LPS)-induced ALI. Methods: The bioactive components of Csrer were identified by ultrahigh-performance liquid chromatography Q-Orbitrap mass spectrometry (UPLC-Q-Orbitrap MS). Active targets predicted from PharmMapper. DrugBank, OMIM, TTD, and GeneCards were used to identify potential targets related to ALI. Intersection genes were identified for Csrer against ALI. The PPI network was analysed to identify prime targets. GO and KEGG analyses were performed. A drug-compound-target-pathway-disease network was constructed. Molecular docking and simulations evaluated the binding free energy between key proteins and active compounds. The protective effect and mechanism of Csrer in ALI were verified using an ALI model in mice. Western blot, Immunohistochemistry and TUNEL staining evaluated the mechanisms of the pulmonary protective effects of Csrer. Results: Forty-six bioactive components, one hundred and ninety-two potential cross-targets against ALI and ten core genes were identified. According to GO and KEGG analyses, the PI3K-Akt, apoptosis and p53 pathways are predominantly involved in the "Csrer-ALI" network. According to molecular docking and dynamics simulations, ten key genes were firmly bound by the principal active components of Csrer. The "Csrer-ALI" network was revealed to be mediated by the p53-mediated apoptosis and inflammatory pathways in animal experiments. Conclusion: Csrer is a reliable source for ALI treatment based on its practical components, potential targets and pathways.

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.

Elucidating the role of Rhodiola rosea L. in sepsis-induced acute lung injury via network pharmacology: emphasis on inflammatory response, oxidative stress, and the PI3K-AKT pathway

Context Sepsis-induced acute lung injury (ALI) is associated with high morbidity and mortality. Rhodiola rosea L. (Crassulaceae) (RR) and its extracts have shown anti-inflammatory, antioxidant, immunomodulatory, and lung-protective effects. Objective This study elucidates the molecular mechanisms of RR against sepsis-induced ALI. Materials and methods The pivotal targets of RR against sepsis-induced ALI and underlying mechanisms were revealed by network pharmacology and molecular docking. Human umbilical vein endothelial cells (HUVECs) were stimulated by 1 μg/mL lipopolysaccharide for 0.5 h and treated with 6.3, 12.5, 25, 50, 100, and 200 μg/mL RR for 24 h. Then, the lipopolysaccharide-stimulated HUVECs were subjected to cell counting kit-8 (CCK-8), enzyme-linked immunosorbent, apoptosis, and Western blot analyses. C57BL/6 mice were divided into sham, model, low-dose (40 mg/kg), mid-dose (80 mg/kg), and high-dose (160 mg/kg) RR groups. The mouse model was constructed through caecal ligation and puncture, and histological, apoptosis, and Western blot analyses were performed for further validation. Results We identified six hub targets (MPO, HRAS, PPARG, FGF2, JUN, and IL6), and the PI3K-AKT pathway was the core pathway. CCK-8 assays showed that RR promoted the viability of the lipopolysaccharide-stimulated HUVECs [median effective dose (ED50) = 18.98 μg/mL]. Furthermore, RR inhibited inflammation, oxidative stress, cell apoptosis, and PI3K-AKT activation in lipopolysaccharide-stimulated HUVECs and ALI mice, which was consistent with the network pharmacology results. Discussion and conclusion This study provides foundational knowledge of the effective components, potential targets, and molecular mechanisms of RR against ALI, which could be critical for developing targeted therapeutic strategies for sepsis-induced ALI.

SIRT1-Rab7 axis attenuates NLRP3 and STING activation through late endosomal-dependent mitophagy during sepsis-induced acute lung injury.

Acute lung injury (ALI) is a leading cause of mortality in patients with sepsis due to proinflammatory endothelial changes and endothelial permeability defects. Mitochondrial dysfunction is recognized as a critical mediator in the pathogenesis of sepsis-induced ALI. Although mitophagy regulation of mitochondrial quality is well recognized, little is known about its role in lung ECs during sepsis-induced ALI. Sirtuin 1 (SIRT1) is a histone protein deacetylase involved in inflammation, mitophagy, and cellular senescence. Here, the authors show a type of late endosome-dependent mitophagy that inhibits NLRP3 and STING activation through SIRT1 signaling during sepsis-induced ALI. C57BL/6J male mice with or without administration of the SIRT1 inhibitor EX527 in the CLP model and lung ECs in vitro were developed to identify mitophagy mechanisms that underlie the cross-talk between SIRT1 signaling and sepsis-induced ALI. SIRT1 deficient mice exhibited exacerbated sepsis-induced ALI. Knockdown of SIRT1 interfered with mitophagy through late endosome Rab7, leading to the accumulation of damaged mitochondria and inducing excessive mitochondrial reactive oxygen species (mtROS) generation and cytosolic release of mitochondrial DNA (mtDNA), which triggered NLRP3 inflammasome and the cytosolic nucleotide sensing pathways (STING) over-activation. Pharmacological inhibition of STING and NLRP3 in vivo or genetic knockdown in vitro reversed SIRT1 deficiency mediated endothelial permeability defects and endothelial inflammation in sepsis-induced ALI. Moreover, activation of SIRT1 with SRT1720 in vivo or overexpression of SIRT1 in vitro protected against sepsis-induced ALI. These findings suggest that SIRT1 signaling is essential for restricting STING and NLRP3 hyperactivation by promoting endosomal-mediated mitophagy in lung ECs, providing potential therapeutic targets for treating sepsis-induced ALI.

Pyroptosis and polarization of macrophages in septic acute lung injury induced by lipopolysaccharide in mice.

Pyroptosis and polarization are significant contributors to the onset and development of many diseases. At present, the relationship between pyroptosis and polarization in acute lung injury (ALI) caused by sepsis remains unclear. The ALI model for sepsis was created in mice and categorized into the blank control, lipopolysaccharide(LPS) group, LPS + low-dose Belnacasan group, LPS + high-dose Belnacasan group, LPS + low-dose Wedelolactone group, LPS + high-dose Wedelolactone group, and positive control group. The wet-dry specific gravity was evaluated to compare pulmonary edema. Hematoxylin-eosin, Masson, and terminal deoxynucleotidyl transferase dUTP nick end labelingstaining techniques were conducted to observe and contrast the pathological changes in lung tissue. ELISA was utilized to identify M1 and M2 macrophages and correlated inflammatory factors. Immunohistochemical staining and flow cytometry were employed to identify markers of M1 and M2 macrophages in lung tissue. Propidium iodidestaining, together with flow cytometry, was utilized to observe the degree and positive rate of pyroptosis of alveolar macrophages. Western blot analysis was conducted to detect the expression levels of Caspase 1, Caspase 11, GSDMD, and IL-18 in the lung tissues of each group. The real-time quantitative polymerase chain reactionmethod was used to ascertain relative expression levels of NLRP3, Caspase 1, Caspase 11, GSDMD, IL-18, iNOS, and Arg-1 in lung tissues of all groups. In mice with sepsis-induced ALI, both classical and nonclassical pathways of pyroptosis are observed. Inhibiting pyroptosis has been found to ameliorate lung injury, pulmonary edema, and inflammation induced by LPS. Notably, the expression of NLRP3, Caspase 1, Caspase 11, GSDMD, IL-1β, IL-18, TGF-β, CD86, CD206, iNOS, and Arg-1 were all altered in this process. Additionally, alveolar macrophages were polarized along with pyroptosis in mice with ALI caused by sepsis. Pyroptosis of alveolar macrophages in the context of ALI in mice infected with sepsis has been linked to the polarization of alveolar macrophages towardtype M1.

Preparation of Dexamethasone-Loaded Nanoparticles and Therapeutic Adoption for Acute Lung Injury in Septic Mice Through the TLR9 Pathway

This research aimed to better exert the efficacy of dexamethasone (DEX) and fabricate an intercellular adhesion molecule A (ILDMA) monoclonal antibody (mAb)-modified nanostructured lipid carrier (NSLC). The anionic DEX NSLC was fabricated by the aqueous solvent diffusion methodology using DEX as the model drug and in combination with various types of lipids. Using N,N’-succinimidyl carbonate as the link, anti-ILDMA mAb-modified anion DEX NSLC (ILDM/DEX/NSLC) and anti-IgG mAb-modified cation DEX NSLC (IgG/DEX/NSLC) were prepared. The total lipid content was controlled unchanged, 3% mass ratio of glyceryl monostearate (MS) in the original prescription was replaced with 3% mass ratio of octadecylamine (ODA), and ILDM/DEX/ODA-NSLC and IgG/DEX/ODA-NSLC were fabricated in the same way. The four NSLCs prepared in the experiment were round in shape and uniform in size. The nanoparticles with a size of approximately 230 nm were similar, and the zeta potentials were (−29.8±21.5) mV, (−27.9±1.6) mV, (36.8±0.8) mV, and (33.7±2.9) mV, respectively. In vitro drug release demonstrated a cumulative release rate of more than 55% of DEX NSLC. The inhibitory rate of DEX NSLC on the activated human vascular endothelial cell line (EAhy926 cell) was dose dependent, and ILDM/DEX/NSLC could transport DEX to activated endothelial cells more efficiently, thus enhancing the intervention ability on diseased endothelium. For the establishment of a sepsis-induced acute lung injury (ALI) mouse model, ILDM/DEX/NSLC was highly distributed in the lung of the model, and its infiltration effect on inflammatory cells was superior to that of other drugs (P &lt; 0.05). Meanwhile, ILDM/DEX/NSLC could more markedly repair the pathological features in the mouse model than other drugs did (P &lt; 0.05). The nanodrug inhibited the protein level of TLR9 in mouse lung tissue to the maximum extent (P &lt; 0.05), thereby enhancing the survival rate of the mice.

FGF18 alleviates sepsis-induced acute lung injury by inhibiting the NF-κB pathway

BackgroundAcute lung injury (ALI) is a devastating clinical disorder with a high mortality rate, and there is an urgent need for more effective therapies. Fibroblast growth factor 18 (FGF18) has potent anti-inflammatory properties and therefore has become a focus of research for the treatment of lung injury. However, the precise role of FGF18 in the pathological process of ALI and the underlying mechanisms have not been fully elucidated.MethodsA mouse model of ALI and human umbilical vein endothelial cells (HUVEC) stimulated with lipopolysaccharide (LPS) was established in vivo and in vitro. AAV-FGF18 and FGF18 proteins were used in C57BL/6J mice and HUVEC, respectively. Vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and p65 protein levels were determined by western blotting or immunofluorescent staining. Afterward, related inhibitors were used to explore the potential mechanism by which FGF18 relieves inflammation.ResultsIn this study, we found that FGF18 was significantly upregulated in LPS-induced ALI mouse lung tissues and LPS-stimulated HUVECs. Furthermore, our studies demonstrated that overexpressing FGF18 in the lung or HUVEC could significantly alleviate LPS-induced lung injury and inhibit vascular leakage.ConclusionsMechanically, FGF18 treatment dramatically inhibited the NF-κB signaling pathway both in vivo and in vitro. In conclusion, these results indicate that FGF18 attenuates lung injury, at least partially, via the NF-κB signaling pathway and therefore may be a potential therapeutic target for ALI.

Carnosol alleviates sepsis-induced pulmonary endothelial barrier dysfunction by targeting nuclear factor erythroid2-related factor 2/sirtuin-3 signaling pathway to attenuate oxidative damage.

Excessive reactive oxygen species production during acute lung injury (ALI) will aggravate the inflammatory process and endothelial barrier dysfunction. Carnosol is a natural phenolic diterpene with antioxidant and anti-inflammatory properties, but its role in treating sepsis-induced ALI remains unclear. This study aims to explore the protective effects and underlying mechanisms of carnosol in sepsis-induced ALI. C57BL/6 mouse were preconditioned with carnosol for 1 h, then the model of lipopolysaccharide (LPS)-induced sepsis was established. The degree of pulmonary edema, oxidative stress, and inflammation were detected. Endothelial barrier function was evaluated by apoptosis and cell junctions. In vitro, Mito Tracker Green probe, JC-1 staining, and MitoSOX staining were conducted to investigate the effect of carnosol on mitochondria. Finally, we investigated the role of nuclear factor-erythroid 2-related factor (Nrf2)/sirtuin-3 (SIRT3) in carnosol against ALI. Carnosol alleviated LPS-induced pulmonary oxidative stress and inflammation by inhibiting excess mitochondrial reactive oxygen species production and maintaining mitochondrial homeostasis. Furthermore, carnosol also attenuated LPS-induced endothelial cell barrier damage by reducing vascular endothelial cell apoptosis and restoring occludin, ZO-1, and vascular endothelial-Cadherin expression in vitro and in vivo. In addition, carnosol increased Nrf2 nuclear translocation to promote SIRT3 expression. The protective effects of carnosol on ALI were largely abolished by inhibition of Nrf2/SIRT3. Our study has provided the first evidence that the Nrf2/SIRT3 pathway is a protective target of the endothelial barrier in ALI, and carnosol can serve as a potential therapeutic candidate for ALI by utilizing its ability to target this pathway.