BACKGROUND: The lack of effective treatments for methicillin-resistant Staphylococcus aureus (MRSA) infection, which often leads to severe acute lung injury (ALI), poses a grave threat to human life. Sophoricoside (SOP), an isoflavone glycoside abundant in the fruit of traditional Chinese herbal Sophora japonica l., showed anti-inflammatory effects against atopic dermatitis, allergic inflammation, and lipopolysaccharide-induced ALI. However, its effect and underlying mechanism on MRSA-induced ALI remain unclear.
OBJECTIVE: The aim of this study is to assess the protective effect of SOP in MRSA-induced ALI and elucidate its underlying molecular mechanisms.
METHODS: In vivo experiments were conducted using wild-type mice to establish MRSA-induced ALI mouse model, and the effects of SOP on ALI were evaluated by hematoxylin-eosin staining, flow cytometry, quantitative real-time polymerase chain reaction, and several biochemical indicators. Adoptive transfer experiments and BTB and CNC homology 1 knockout (Bach1-/-) mice were also utilized in this study. In vitro studies employed murine macrophages RAW264.7 cells, primary bone marrow-derived macrophages (BMDMs), and primary lung macrophages to explore the underlying molecular mechanisms.
RESULTS: The administration of SOP ameliorated MRSA-induced ALI by improving pulmonary histological damages, reducing neutrophil infiltration, suppressing oxidative stress levels, and decreasing the expression of inflammatory cytokines. In isolation experiments with ALI mouse lung macrophages and macrophage adoptive transfer experiments, SOP prevented macrophage activation, thereby reducing the production of proinflammatory cytokines. In vitro experiments demonstrated that SOP decreased the expression of inflammatory mediators in lipoteichoic acid (LTA)-stimulated RAW264.7 cells, BMDMs, and primary lung macrophages. Additionally, SOP inhibited protein kinase B (Akt) phosphorylation and treatment with MK2206-a specific inhibitor of Akt-eliminated SOP\'s ability to suppress LTA-stimulated macrophage inflammation. Furthermore, stimulation with LTA or MRSA up-regulated Bach1 expression; however, deletion of Bach1 abolished the inhibitory effect of SOP on p-Akt activation as well as inflammation and ALI development.
CONCLUSIONS: This study provides the first evidence that SOP effectively mitigates MRSA-induced ALI via suppressing macrophage activation through the inhibition of Bach1/Akt pathway. These findings highlight the potential of SOP as a novel therapeutic agent for treating MRSA-induced ALI.

Acute lung injury (ALI) is a common complication after hemorrhagic shock (HS), which is associated with HS-induced inflammatory response, oxidative stress, and cell apoptosis. This study aimed to investigate the therapeutic efficacy of 8-Gingerol, a constituent extracted from ginger, on ALI after HS in rats. We established a fixed press hemorrhage model in SD rats, in which the HS rats were administered 15 or 30 mg/kg of 8-Gingerol by intraperitoneal injection before fluid resuscitation. H&E staining and TUNEL staining were performed to evaluate histopathological changes and cell apoptosis in lung tissues, respectively. Quantitative reverse transcription PCR and Western blot were used to measure gene and protein expression. Pro-inflammatory cytokines were detected by ELISA kits. Immunofluorescence of myeloperoxidase was used to evaluate neutrophil infiltration. 8-Gingerol reduced pulmonary edema, alveolar wall thickness, and cell apoptosis in lung tissues of HS rats. Regarding inflammatory responses, 8-Gingerol attenuated neutrophil infiltration in lung tissues, reduced pro-inflammatory cytokines in lung tissues and bronchoalveolar lavage fluid, and decreased the levels of NLRP3, ASC, and cleaved caspase 1 in lung tissues. Additionally, 8-Gingerol ameliorated oxidative stress in lung tissues as evidenced by increased antioxidant indicators (SOD and GSH) and decreased production of MDA and ROS. The therapeutic effects of 8-Gingerol were associated with the regulation of MAPK and Nrf2/HO-1 pathways. These results support 8-Gingerol as a promising drug for the treatment of HS-induced ALI.

BACKGROUND: Aberrant activation of macrophages is associated with pathogenesis of acute lung injury (ALI). However, the potential pathogenesis has not been explored.
OBJECTIVE: We aimed to identify whether histone deacetylase (HDAC) 10 is involved in lipopolysaccharide (LPS)-exposed ALI and reveal the underlying pathogenesis by which it promotes lung inflammation in LPS-exposed ALI via modifying P62 with deacetylation.
METHODS: We constructed an ALI mice model stimulated with LPS to determine the positive effect of Hdac10 deficiency. Moreover, we cultured murine alveolar macrophage cell line (MH-S cells) and primary bone marrow-derived macrophages (BMDMs) to explore the pro-inflammatory activity and mechanism of HDAC10 after LPS challenge.
RESULTS: HDAC10 expression was increased both in mice lung tissues and macrophage cell lines and promoted inflammatory cytokines production exposed to LPS. Hdac10 deficiency inhibited autophagy and inflammatory response after LPS stimulation. In vivo, Hdac10fl/fl-LysMCre mice considerably attenuated lung inflammation and inflammatory cytokines release exposed to LPS. Mechanistically, HDAC10 interacts with P62 and mediates P62 deacetylation at lysine 165 (K165), by which it promotes P62 expression and increases inflammatory cytokines production. Importantly, we identified that Salvianolic acid B (SAB), an HDAC10 inhibitor, reduces lung inflammatory response in LPS-stimulated ALI.
CONCLUSIONS: These results uncover a previously unknown role for HDAC10 in regulating P62 deacetylation and aggravating lung inflammation in LPS-induced ALI, implicating that targeting HDAC10 is an effective therapy for LPS-exposed ALI.

OBJECTIVE: Astragaloside IV (AS-IV) is a natural triterpenoid saponin compound with a variety of pharmacological effects, and several studies have clarified its anti-inflammatory effects, which may make it an effective alternative treatment against inflammation. In the study, we aimed to investigate whether AS-IV could attenuate the inflammatory response to acute lung injury and its mechanisms.
METHODS: Different doses of AS-IV (20mg·kg-1, 40mg·kg-1, and 80mg·kg-1) were administered to the ALI rat model, followed by collection of serum and broncho alveolar lavage fluid (BALF) for examination of the inflammatory response, and HE staining of the lung and colon tissues, and interpretation of the potential molecular mechanisms by quantitative real-time PCR (qRT-PCR), Western blotting (WB). In addition, fecal samples from ALI rats were collected and analyzed by 16S rRNA sequencing.
RESULTS: AS-IV decreased the levels of TNF-α, IL-6, and IL-1β in serum and BALF of mice with Acute lung injury (ALI). Lung and colon histopathology confirmed that AS-IV alleviated inflammatory infiltration, tissue edema, and structural changes. qRT-PCR and WB showed that AS-IV mainly improved inflammation by inhibiting the expression of PI3K, AKT and mTOR mRNA, and improved the disorder of intestinal microflora by increasing the number of beneficial bacteria and reducing the number of harmful bacteria.
CONCLUSIONS: AS-IV reduces the expression of inflammatory factors by inhibiting the PI3K/AKT/mTOR pathway and optimizes the composition of the gut microflora in AIL rats.

This study aimed to assess the prophylactic effects of Berberine on experimentally induced lung sepsis and examine its effects on selected cytokines, genes, and protein expression besides the histopathological evaluation. Berberine significantly reduced the wet/dry lung ratio, the broncho-alveolar lavage fluid (BALF) protein, cells, neutrophils percentage, and cytokines levels. In addition, pretreatment with Berberine decreased the myeloperoxidase (MPO) and malondialdehyde (MDA) levels and decreased gene expression of nuclear factor kappa B (NF-κB), monocyte chemoattractant protein-1 (MCP-1), and the intracellular adhesion molecule 1 (ICAM-1) by RT-qPCR analysis, revealing Berberine\'s antioxidant and anti-inflammatory mode of action. Western blot analysis revealed increased peroxisome proliferator-activated receptor gamma (PPAR-γ) expression in the Berberine pretreated group compared to the cecal ligation and puncture (CLP) group, in which the histopathological examination evidenced this improvement. In conclusion, Berberine improved lung sepsis via its PPAR-γ mediated antioxidant and anti-inflammatory effects.

Sepsis is a clinically life-threatening syndrome, and acute lung injury is the earliest and most serious complication. We aimed to assess the role of kruppel-like factor 13 (KLF13) in lipopolysaccharide (LPS)-induced human alveolar type II epithelial cell damage and to reveal the possible mechanism related to peroxisome proliferator-activated receptor-γ co-activator 1-α (PGC-1α). In LPS-treated A549 cells with or without KLF13 overexpression or PGC-1α knockdown, cell viability was measured by a cell counting kit-8 assay. Enzyme-linked immunosorbent assay kits detected the levels of inflammatory factors, and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining measured cell apoptosis. Besides, mitochondrial reactive oxygen species (MitoSOX) and mitochondrial membrane potential were detected using MitoSOX red- and JC-1 staining. Expression of proteins related to mitochondrial quality control (MQC) was evaluated by western blot. Co-immunoprecipitation (Co-IP) assay was used to analyze the interaction between KLF13 and PGC-1α. Results indicated that KLF13 was highly expressed in LPS-treated A549 cells. KLF13 upregulation elevated the viability and reduced the levels of inflammatory factors in A549 cells exposed to LPS. Moreover, KLF13 gain-of-function inhibited LPS-induced apoptosis of A549 cells, accompanied by upregulated BCL2 expression and downregulated Bax and cleaved caspase3 expression. Furthermore, MQC was improved by KLF13 overexpression, as evidenced by decreased MitoSOX, JC-1 monomers and increased JC-1 aggregates, coupled with the changes of proteins related to MQC. In addition, Co-IP assay confirmed the interaction between KLF13 and PGC-1α. PGC-1α deficiency restored the impacts of KLF13 upregulation on the inflammation, apoptosis, and MQC in LPS-treated A549 cells. In conclusion, KLF13 attenuated LPS-induced alveolar epithelial cell inflammation and apoptosis by regulating MQC via binding PGC-1α.

BACKGROUND: Endothelial barrier dysfunction is critical for the pathogenesis of sepsis-induced acute lung injury (ALI). Lipopolysaccharide (LPS)-stimulated human pulmonary microvascular endothelial cells (HPMECs) are widely used as the cell model of sepsis-associated ALI for exploration of endothelial barrier dysfunction. Dickkopf (DKK) family proteins were reported to mediate endothelial functions in various diseases. The present study explored the effect of Dickkopf-3 (DKK3) on endothelial barrier permeability, angiogenesis, and tight junctions in LPS-stimulated HPMECs.
METHODS: RT-qPCR was required for detecting DKK3 and miR-98-3p expression. The angiogenesis of HPMECs was evaluated by tube formation assays. Monolayer permeability of HPMECs was examined by Transwell rhodamine assays. The protein expression of DKK3 and tight junctions in HPMECs was measured via western blotting. Luciferase reporter assay was used to verify the interaction between miR-98-3p and DKK3.
RESULTS: LPS treatment inhibited angiogenetic ability while increasing the permeability of HPMECs. DKK3 expression was upregulated while miR-98-3p level was reduced in LPS-treated HPMECs. DKK3 knockdown alleviated HPMEC injury triggered by LPS stimulation. MiR-98-3p targeted DKK3 in HPMECs. Overexpression of miR-98-3p protects HPMECs from the LPS-induced endothelial barrier dysfunction, and the protective effect was reversed by DKK3 overexpression.
CONCLUSIONS: MiR-98-3p ameliorates LPS-evoked pulmonary microvascular endothelial barrier dysfunction in sepsis-associated ALI by targeting DKK3.

BACKGROUND: Acute lung injury (ALI) is manifested by increased blood vessel permeability within the lungs and subsequent impairment of alveolar gas exchange. Methylprednisolone (MP) is commonly used as a treatment for ALI to reduce inflammation, yet its molecular mechanism remains unclear. This study aims to explore the underlying mechanisms of MP on ALI in a model induced by lipopolysaccharide (LPS).
METHODS: The proliferation, viability, apoptosis, and miR-151-5p expression of alveolar type II epithelial cells (AECII) were detected using the cell EdU assay, Annexin V/PI Apoptosis Kit, counting kit-8 (CCK-8) assay, and RT-qPCR. Western blot analysis was used to detect the Usp38 protein level. IL-6 and TNF-α were measured by ELISA. The combination of miR-151-5p and USP38 was determined by chromatin immunoprecipitation (ChIP)-PCR and dual-luciferase reporter assay.
RESULTS: MP greatly improved pulmonary function in vivo, reduced inflammation, and promoted the proliferation of the alveolar type II epithelial cells (AECII) in vitro. By comparing the alterations of microRNAs in lung tissues between MP treatment and control groups, we found that miR-151-5p exhibited a significant increase after LPS-treated AECII, but decreased after MP treatment. Confirmed by a luciferase reporter assay, USP38, identified as a downstream target of miR-151-5p, was found to increase after MP administration. Inhibition of miR-151-5p or overexpression of USP38 in AECII significantly improved the anti-inflammatory, anti-apoptotic, and proliferation-promotive effects of MP.
CONCLUSIONS: In summary, our data demonstrated that MP alleviates the inflammation and apoptosis of AECII induced by LPS, and promotes the proliferation of AECII partially via miR-151-5p suppression and subsequent USP38 activation.

BACKGROUND: Although umbilical cord mesenchymal stem cell (UCMSC) infusion has been proposed as a promising strategy for the treatment of acute lung injury (ALI), the parameters of UCMSC transplantation, such as infusion routes and doses, need to be further optimized.
METHODS: In this study, we compared the therapeutic effects of UCMSCs transplanted via intravenous injection and intratracheal instillation on lipopolysaccharide-induced ALI using a rat model. Following transplantation, levels of inflammatory factors in serum; neutrophils, total white blood cells, and lymphocytes in bronchoalveolar lavage fluid (BALF); and lung damage levels were analyzed.
RESULTS: The results indicated that UCMSCs administered via both intravenous and intratracheal routes were effective in alleviating ALI, as determined by analyses of arterial blood gas, lung histopathology, BALF contents, and levels of inflammatory factors. Comparatively, the intratracheal instillation of UCMSCs was found to result in lower levels of lymphocytes and total proteins in BALF, whereas greater reductions in the serum levels of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were detected in rats receiving intravenously injected stem cells.
CONCLUSIONS: Our findings in this study provide convincing evidence to indicate the efficacy of UCMSC therapy in the treatment of ALI mediated via different delivery routes, thereby providing a reliable theoretical basis for further clinical studies. Moreover, these findings imply that the effects obtained using the two assessed delivery routes for UCMSC transplantation are mediated via different mechanisms, which could be attributable to different cellular or molecular targets.

OBJECTIVE: To investigate the therapeutic effect and mechanism of sivelestat sodium on acute lung injury (AIL).
METHODS: A rat model for ALI/acute respiratory distress syndrome (ALI/ARDS) was established. Pathological examination of lung tissue was conducted to assess lung injury. Blood gas in the arteries was measured using a blood analyzer. Changes in PaO2, PaO2/FiO2, and lung wet/dry (W/D) weight ratio were carefully compared. ELISA assay was conducted to estimate cell adhesion and inflammation response. Finally, real-time reverse transcription polymerase chain reaction and western blotting assay was used to determine the activation of PI3K/AKT/mTOR pathway.
RESULTS: ARDS in vivo model was successfully constructed by LPS injection. Compared with the sham group, PaO2 and PaO2/FiO2 were significantly lower in the vehicle group, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8 andTNF-αwere significantly increased. After treatment with different doses of sivelestat sodium, we found PaO2, PaO2/FiO2 were prominently increased, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8, TNF-α levels were decreased in the dose-dependent manner. Meanwhile, compared with the vehicle group, the expression levels of Bax, PI3K, Akt and mTOR were significantly lower, and the expression of Bcl-2 was significantly higher after injection with sivelestat sodium.
CONCLUSIONS: Sivelestat sodium has an interventional effect on ALI in sepsis by inhibiting the PI3K/AKT/mTOR signalling pathway.