A COX-2/sEH dual inhibitor PTUPB alleviates lipopolysaccharide-induced acute lung injury in mice by inhibiting NLRP3 inflammasome activation

Dexmedetomidine attenuates sepsis-associated acute lung injury by regulating macrophage efferocytosis through the ROS/ADAM10/AXL pathway

BACKGROUND

The lungs are highly susceptible to damage during sepsis, with severe lung injury potentially progressing to acute respiratory distress syndrome and even fatal sepsis. Effective efferocytosis of apoptotic cells is crucial in alleviating inflammation and tissue injury.

METHODS

We established a septic lung injury mouse model via intraperitoneal injection of lipopolysaccharide. Lung injury was assessed by histology, immunofluorescence, neutrophil immunohistochemistry staining, and cytokine detection. We extracted alveolar macrophages by bronchoalveolar lavage and primary macrophages from mouse bone marrow to investigate the regulatory effects of Dexmedetomidine (DEX) on efferocytosis. We further validated the molecular mechanisms underlying the regulation of macrophage efferocytosis by DEX through knockdown of AXL expression. Additionally, we examined the efferocytic ability of monocytes isolated from patients.

RESULTS

We discovered that DEX treatment effectively alleviated pulmonary injury and inflammation. Lipopolysaccharide reduced macrophage efferocytosis and AXL expression which were reversed by DEX. We also found DEX inhibited the increased activation of A Disintegrin And Metalloproteinase 10 (ADAM10) and the production of soluble AXL. Moreover, our findings demonstrated that DEX decreased the elevated ROS production linked to higher ADAM10 activation. Blocking AXL negated DEX's benefits on efferocytosis and lung protection. Efferocytosis in monocytes from septic lung injury patients was notably lower than in healthy individuals.

CONCLUSION

Our findings demonstrated that DEX treatment effectively reduces septic lung injury by promoting macrophage efferocytosis through ROS/ADAM10/AXL signaling pathwway.

Clustering human dental pulp fibroblasts spontaneously activate NLRP3 and AIM2 inflammasomes and induce IL-1β secretion

Objectives

The objective of the present study was to investigate whether NOD-like receptor family pyrin domain-containing 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammasomes pathways were involved in an experimental model of fibroblast activation named nemosis, which was used to mimic circumstances without bacteria stimulation.

Methods

Nemosis of human dental pulp fibroblast (DPFs) was induced by three-dimensional culture in U-shaped 96-well plates and investigated by scanning electron microscopy (SEM). DPFs monolayers were used as control. Annexin V-FITC/7-AAD apoptosis assay was performed on the DPFs spheroids by flowcytometry. Caspase-1 activity detection assay was conducted on the DPFs spheroids. Quantitative real-time polymerase chain reaction (qRT-PCR), cytokine measurements, Western blot and the effect of COX-2 inhibitor on spheroids was studied.

Results

SEM study observed human dental pulp fibroblast clusters and cell membranes damage on the surface of DPFs spheroids. The percentages of necrotic cells from DPFs spheroids gradually increased as the incubation time increased. A statistically significant increase in caspase-1 activity was observed after DPFs spheroids formation. DPFs spheroids displayed significant amounts of NLRP3, AIM2 mRNA and protein expression, caspase-1 mRNA expression and cleaved Caspase-1 protein expression and high IL-1β concentrations (P < 0.05) than DPFs monolayers. Specific COX-2 inhibitor (NS-398) decreased NLRP3 mRNA and protein expression, cleaved Caspase-1 protein expression, Caspase-1 activity and IL-1β mRNA expression and IL-1β concentrations (P < 0.05). However, Specific COX-2 inhibitor had no impact on AIM2 mRNA and protein expression, caspase-1 mRNA expression and pro-Caspase-1 protein expression.

Conclusions

In conclusion, clustering human DPFs spontaneously activated NLRP3 and AIM2 inflammasomes and induced IL-1β secretion which could be partially attenuated by COX-2 inhibitor. Thus, nemosis could become a powerful model for studying mechanisms underlying aseptic pulpitis.

Electroacupuncture pretreatment maintains mitochondrial quality control via HO-1/MIC60 signaling pathway to alleviate endotoxin-induced acute lung injury

Electroacupuncture has been demonstrated to mitigate endotoxin-induced acute lung injury by enhancing mitochondrial function. This study investigates whether electroacupuncture confers lung protection through the regulation of mitochondrial quality control mediated by heme oxygenase-1 (HO-1) and the mitochondrial inner membrane protein MIC60. HO-1, an inducible stress protein, is crucial for maintaining mitochondrial homeostasis and protecting against lung injury. MIC60, a key component of the mitochondrial contact site and cristae organizing system, supports mitochondrial integrity. We employed genetic knockout/silencing and cell transfection techniques to model lipopolysaccharide (LPS)-induced lung injury, assessing changes in mitochondrial structure, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and the expression of proteins essential for mitochondrial quality control. Our findings reveal that electroacupuncture alleviates endotoxin-induced acute lung injury and associated mitochondrial dysfunction, as evidenced by reductions in lung injury scores, decreased ROS production, and suppressed expression of proteins involved in mitochondrial fission and mitophagy. Additionally, electroacupuncture enhanced MMP and upregulated proteins that facilitate mitochondrial fusion and biogenesis. Importantly, the protective effects of electroacupuncture were reduced in models with Hmox1 knockout or Mic60 silencing, and in macrophages transfected with Hmox1-siRNA or Mic60-siRNA. Moreover, HO-1 was found to influence MIC60 expression during electroacupuncture preconditioning and LPS challenge, demonstrating that these proteins not only co-localize but also interact directly. In conclusion, electroacupuncture effectively modulates mitochondrial quality control through the HO-1/MIC60 signaling pathway, offering an adjunctive therapeutic strategy to ameliorate endotoxin-induced acute lung injury in both in vivo and in vitro settings.

Restoration of ARA metabolic disorders in vascular smooth muscle cells alleviates intimal hyperplasia

Intimal hyperplasia (IH) is an innegligible issue for patients undergoing interventional therapy. The proliferation and migration of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor-BB (PDGF-BB) are critical events in the development of IH. While the exact mechanism and effective target for IH needs further investigation. Metabolic disorders of arachidonic acid (ARA) are involved in the occurrence and progression of various diseases. In this study, we found that the expressions of soluble epoxide hydrolase (sEH) and cyclooxygenase-2 (COX-2) were significantly increased in the VSMCs during balloon injury-induced IH. Then, we employed a COX-2/sEH dual inhibitor PTUPB to increase the concentration of epoxyeicosatrienoic acids (EETs) while prevent the release of pro-inflammatory prostaglandins. Results showed that PTUPB treatment significantly reduced neointimal thickening induced by balloon injury in rats in vivo and inhibited PDGF-BB-induced proliferation and migration of VSMCs in vitro. Our results showed that PTUPB may reverse the phenotypic transition of VSMCs by inhibiting Pttg1 expression. In conclusion, we found that the dysfunction of ARA metabolism in VSMCs contributes to IH, and the COX-2/sEH dual inhibitor PTUPB attenuates IH progression by reversing the phenotypic switch in VSMC through the Sirt1/Pttg1 pathway.

Design, synthesis, and biological evaluation of oridonin derivatives as novel NLRP3 inflammasome inhibitors for the treatment of acute lung injury

Acute lung injury (ALI) is a severe respiratory disorder closely associated with the excessive activation of the NLRP3 inflammasome. Oridonin (Ori), a natural diterpenoid compound, had been confirmed as a specific covalent NLRP3 inflammasome inhibitor, which was completely different from that of MCC950. However, the further clinical application of Ori was limited by its weak inhibitory activity against NLRP3 inflammasome (IC50 = 1240.67 nM). Fortunately, through systematic structure-optimization of Ori, D6 demonstrated the enhancement of IL-1β inhibitory activity (IC50 = 41.79 nM), which was better than the parent compound Ori. Then, by using SPR, molecular docking and MD simulation, D6 was verified to directly interact with NLRP3 via covalent and non-covalent interaction. The further anti-inflammatory mechanism studies were revealed that D6 could inhibit the activation of NLRP3 inflammasome without affecting the initiation phase of NLRP3 inflammasome activation, and D6 was a broad-spectrum and selective NLRP3 inflammasome inhibitor. Finally, D6 demonstrated a favorable therapeutic effect on LPS-induced ALI in mice model, and the potent pharmacodynamic effect of D6 was correlated with the specific inhibition of NLRP3 inflammasome activation in vivo. Thus, D6 is proved as a potent NLRP3 inhibitor, and has the potential to develop as a novel anti-ALI agent.

A regulatory loop involving the cytochrome P450-soluble epoxide hydrolase axis and TGF-β signaling

Fatty acid metabolites, produced by cytochrome P450 enzymes and soluble epoxide hydrolase (sEH), regulate inflammation. Here, we report that the transforming growth factor β (TGF-β)-induced polarization of macrophages to a pro-resolving phenotype requires Alk5 and Smad2 activation to increase sEH expression and activity. Macrophages lacking sEH showed impaired repolarization, reduced phagocytosis, and maintained a pro-inflammatory gene expression profile. 11,12-Epoxyeicosatrienoic acid (EET) was one altered metabolite in sEH-/- macrophages and mimicked the effect of sEH deletion on gene expression. Notably, 11,12-EET also reduced Alk5 expression, inhibiting TGF-β-induced Smad2 phosphorylation by triggering the cytosolic translocation of the E3 ligase Smurf2. These findings suggest that sEH expression is controlled by TGF-β and that sEH activity, which lowers 11,12-EET levels and promotes TGF-β signaling by metabolizing 11,12-EET to prevent Alk5 degradation. Thus, an autocrine loop between sEH/11,12-EET and TGF-β1 regulates macrophage function.

BCAP31 Alleviates Lipopolysaccharide-Mediated Acute Lung Injury via Induction of PINK1/Parkin in Alveolar Epithelial Type II Cell

Background: B-cell receptor-associated protein 31 (BCAP31) has protective effects against alveolar epithelial type II cells (AECII) damage by inhibiting mitochondrial injury in acute lung injury (ALI) induced by lipopolysaccharide (LPS), whereas the precise mechanism is still unclear. It is known that PTEN-induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy can remove damaged mitochondria selectively, which may be involved in BCAP31 protection against mitochondrial injury. Methods: In the current study, ALI mice models were established by using surfactant protein C (Sftpc)-BCAP31 transgenic mice (BCAP31TG mice) and AECII-specific BCAP31 knockout mice (BCAP31CKO mice) treated with LPS. Results: BCAP31 expression in lung tissue and AECII were inhibited in ALI mice. Under LPS challenge, lower level of BCAP31 was found to correlate positively with pathological injury of the lung, respiratory dysfunction, mortality rates, inflammation response, and AECII damage. Further study showed that down-regulation of BCAP31 induced decreased phosphorylation of PINK1 via reduced binding to PINK1, thereby restraining PINK1/Parkin-mediated mitophagy. Down-regulation of mitophagy promoted mitochondrial injury, as shown by the increase in mitochondrial permeability transition pore opening rate, together with enhanced mitochondrial reactive oxygen species (mROS), which were accompanied by increased cellular apoptosis and reactive oxygen species (ROS). The increased cellular ROS contributed to the inflammatory response via activation of nuclear factor κB (NF-κB). In contrast, BCAP31 overexpression promoted phosphorylation of PINK1 and PINK1/Parkin-mediated mitophagy, thus blocking the mROS/ROS/NF-κB pathway, favoring a protective condition that ultimately led to the inhibition of AECII apoptosis and inflammatory response in LPS-induced ALI. Conclusion: Ultimately, BCAP31 alleviated ALI by activating PINK1/Parkin-mediated mitophagy and blocking the mROS/ROS/NF-κB pathway in AECII.

Octreotide protects against LPS-induced endothelial cell and lung injury

Growth hormone (GH) is a crucial regulator of growth, cell reproduction, and regeneration; and it is controlled by growth hormone-releasing hormone (GHRH) and somatostatin. Lipopolysaccharides (LPS) can compromise endothelial function, leading to increased inflammation and vascular leak. Octreotide (OCT) is an FDA-approved synthetic somatostatin analog (SSA) used to treat acromegaly and neuroendocrine tumors. The present study investigates the effects of OCT on LPS-induced injury in bovine and human lung endothelial cells, as well as in mouse lungs. Our in vitro observations suggest that OCT effectively counteracts LPS-induced endothelial leak, inflammation, and reactive oxygen species (ROS) generation. Furthermore, OCT reduces bronchoalveolar lavage fluid (BALF) protein concentration in an experimental model of Acute Lung Injury (ALI). Our study suggests that OCT mitigates LPS-induced endothelial cell and lung injury, suggesting that it may represent an exciting therapeutic possibility in diseases related to barrier dysfunction.

Natural hydrogen gas and engineered microalgae prevent acute lung injury in sepsis

Background

Hydrogen gas and microalgae both exist in the natural environment. We aimed to integrate hydrogen gas and biology nano microalgae together to expand the treatment options in sepsis.

Methods

Phosphoproteomics, metabolomics and proteomics data were obtained from mice undergoing cecum ligation and puncture (CLP) and inhalation of hydrogen gas. All omics analysis procedure were accordance with standards. Multi R packages were used in single cell and spatial transcriptomics analysis to identify primary cells expressing targeted genes, and the genes' co-expression relationships in sepsis related lung landscape. Then, network pharmacology method was used to identify candidate drugs. We used hydrophobic-force-driving self-assembly method to construct dihydroquercetin (DQ) nanoparticle. To cooperate with molecular hydrogen, ammonia borane (B) was added to DQ surface. Then, Chlorella vulgaris (C) was used as biological carrier to improve self-assembly nanoparticle. Vivo and vitro experiments were both conducted to evaluate anti-inflammation, anti-ferroptosis, anti-infection and organ protection capability.

Results

As a result, we identified Esam and Zo-1 were target phosphorylation proteins for molecular hydrogen treatment in lung. Ferroptosis and glutathione metabolism were two target pathways. Chlorella vulgaris improved the dispersion of DQB and reconstructed morphological features of DQB, formed DQB@C nano-system (size = 307.3 nm, zeta potential = -22mv), with well infection-responsive hydrogen release capability and biosafety. In addition, DQB@C was able to decrease oxidative stress and inflammation factors accumulation in lung cells. Through increasing expression level of Slc7a11/xCT and decreasing Cox2 level to participate with the regulation of ferroptosis. Also, DQB@C played lung and multi organ protection and anti-inflammation roles on CLP mice.

Conclusion

Our research proposed DQB@C as a novel biology nano-system with enormous potential on treatment for sepsis related acute lung injury to solve the limitation of hydrogen gas utilization in clinics.

Total flavonoids from the aerial parts of Tetrastigma hemsleyanum prevent LPS-induced ALI by modulating the TLR4/NF-κB pathway in mice

BACKGROUND

The traditional Chinese medicine Tetrastigma Hemsleyanum (TH) is employed in treating respiratory diseases; however, the aerial parts by which its total flavonoids alleviate acute lung injury (ALI) are still unknown. This study investigated the protective effect and mechanism of Tetrastigma Hemsleyanum flavonoids (THF) in lipopolysaccharide (LPS)-induced ALI in mice.

METHODS

Firstly, the total flavonoids from the above-ground part of TH were extracted. Subsequently, the composition of THF was analyzed using LC-MS. In vivo, the impact of THF on ALI mice was assessed through lung histopathology and the evaluation of various inflammatory factors' expression in mice. After treating RAW264.7 cells with THF in vitro, changes in inflammatory markers were examined upon LPS stimulation, and mRNA expression levels of inflammatory factors were detected using RT-qPCR. Finally, Western blot analysis was performed to determine TLR4/NF-κB pathway-associated proteins expression.

RESULTS

In summary, a total of 24 flavonoids have been identified in THF. In vivo and vitro results show that THF effectively reduces the damage caused by LPS inflammation by blocking the expression and release of inflammatory factors. THF alleviates inflammatory injury by modulating the TLR4/NF-KB pathway.

CONCLUSION

The results suggest that flavonoids exhibit a potent anti-inflammatory effect and effectively mitigate LPS-induced injury both in vivo and in vitro. We suggested that these flavonoids exert their therapeutic effects by modulating the TLR4/NF-KB pathway. In conclusion, the development of THF is anticipated to represent a promising new pharmaceutical for treatingALI.

Neutrophil extracellular traps trigger alveolar epithelial cell necroptosis through the cGAS-STING pathway during acute lung injury in mice

Extensive loss of alveolar epithelial cells (AECs) undergoing necroptosis is a crucial mechanism of acute lung injury (ALI), but its triggering mechanism needs to be thoroughly investigated. Neutrophil extracellular traps (NETs) play a significant role in ALI. However, the effect of NETs on AECs' death has not been clarified. Our study found that intratracheal instillation of NETs disrupted lung tissue structure, suggesting that NETs could induce ALI in mice. Moreover, we observed that NETs could trigger necroptosis of AECs in vivo and in vitro. The phosphorylation levels of RIPK3 and MLKL were increased in MLE12 cells after NETs treatment (P < 0.05). Mechanistically, NETs taken up by AECs through endocytosis activated the cGAS-STING pathway and triggered AECs necroptosis. The expression of cGAS, STING, TBK1 and IRF3 were increased in MLE12 cells treated with NETs (P < 0.05). Furthermore, the cGAS inhibitor RU.521 inhibited NETs-triggered AECs necroptosis and alleviated the pulmonary damage induced by NETs in mice. In conclusion, our study demonstrates that NETs taken up by AECs via endocytosis can activate the cGAS-STING pathway and trigger AECs necroptosis to promote ALI in mice. Our findings indicate that targeting the NETs/cGAS-STING/necroptosis pathway in AECs is an effective strategy for treating ALI.

Regulation of YAP translocation by myeloid Pten deficiency alleviates acute lung injury via inhibition of oxidative stress and inflammation

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is intricately involved in modulating the inflammatory response in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Nevertheless, the myeloid PTEN governing Hippo-YAP pathway mediated oxidative stress and inflammation in lipopolysaccharide (LPS)-induced ALI remains to be elucidate.

METHODS

The floxed Pten (PtenFL/FL) and myeloid-specific Pten knockout (PtenM-KO) mice were intratracheal instill LPS (5 mg/kg) to establish ALI, then Yap siRNA mix with the mannose-conjugated polymers was used to knockdown endogenous macrophage YAP in some PtenM-KO mice before LPS challenged. The bone marrow-derived macrophages (BMMs) from PtenFL/FL and PtenM-KO mice were obtained, and BMMs were transfected with CRISPR/Cas9-mediated glycogen synthase kinase 3 Beta (GSK3β) knockout (KO) or Yes-associated protein (YAP) KO vector subjected to LPS (100 ng/ml) challenged or then cocultured with MLE12 cells.

RESULTS

Here, our findings demonstrate that myeloid-specific PTEN deficiency exerts a protective against LPS-induced oxidative stress and inflammation dysregulated in ALI model. Moreover, ablation of the PTEN-YAP axis in macrophages results in reduced nuclear factor-E2-related factor-2 (NRF2) expression, a decrease in antioxidant gene expression, augmented levels of free radicals, lipid and protein peroxidation, heightened generation of pro-inflammatory cytokines, ultimately leading to increased apoptosis in MLE12 cells. Mechanistically, it is noteworthy that the deletion of myeloid PTEN promotes YAP translocation and regulates NRF2 expression, alleviating LPS-induced ALI via the inhibition of GSK3β and MST1 binding.

CONCLUSIONS

Our study underscores the crucial role of the myeloid PTEN-YAP-NRF2 axis in governing oxidative stress and inflammation dysregulated in ALI, indicating its potential as a therapeutic target for ALI.

HSPB8 attenuates lipopolysaccharide‑mediated acute lung injury in A549 cells by activating mitophagy

Sepsis is a life‑threatening multiple organ failure disease caused by an uncontrolled inflammatory response and can progress to acute lung injury (ALI). Heat‑shock protein B8 (HSPB8) serves a cytoprotective role in multiple types of diseases; however, to the best of our knowledge, the regulatory role of HSPB8 in sepsis‑induced ALI remains unclear. A549 human alveolar type II epithelial cells were treated with lipopolysaccharide (LPS) for 24 h to simulate a sepsis‑induced ALI model. Cell transfection was performed to overexpress HSPB8, and cells were treated with mitochondrial division inhibitor‑1 (Mdivi‑1) for 2 h before LPS induction to assess the underlying mechanism. Protein expression was evaluated using western blotting and an immunofluorescence assay. Cytokines were examined using ELISA assay kits and antioxidant enzymes were examined using their detection kits. Cell apoptosis was detected using flow cytometry. The mitochondrial membrane potential was detected by JC‑1 staining. HSPB8 was upregulated in A549 cells treated with LPS and HSPB8 overexpression attenuated LPS‑induced inflammatory cytokine levels, oxidative stress and apoptosis in A549 cells. LPS inhibited mitophagy and reduced the mitochondrial membrane potential in A549 cells, which was partly inhibited by HSPB8 overexpression. Furthermore, Mdivi‑1 decreased the inhibitory effect of HSPB8 on the inflammatory response, oxidative stress and apoptosis in LPS‑treated A549 cells. In conclusion, HSPB8 overexpression attenuated the LPS‑mediated inflammatory response, oxidative stress and apoptosis in A549 cells by promoting mitophagy, indicating HSPB8 as a potential therapeutic target in sepsis‑induced ALI.

Targeting miR-29 mitigates skeletal senescence and bolsters therapeutic potential of mesenchymal stromal cells

Mesenchymal stromal cell (MSC) senescence is a key factor in skeletal aging, affecting the potential of MSC applications. Identifying targets to prevent MSC and skeletal senescence is crucial. Here, we report increased miR-29 expression in bone tissues of aged mice, osteoporotic patients, and senescent MSCs. Genetic overexpression of miR-29 in Prx1-positive MSCs significantly accelerates skeletal senescence, reducing cortical bone thickness and trabecular bone mass, while increasing femur cross-sectional area, bone marrow adiposity, p53, and senescence-associated secretory phenotype (SASP) levels. Mechanistically, miR-29 promotes senescence by upregulating p53 via targeting Kindlin-2 mRNA. miR-29 knockdown in BMSCs impedes skeletal senescence, enhances bone mass, and accelerates calvarial defect regeneration, also reducing lipopolysaccharide (LPS)-induced organ injuries and mortality. Thus, our findings underscore miR-29 as a promising therapeutic target for senescence-related skeletal diseases and acute inflammation-induced organ damage.

sEH activity is associated with mortality in patients with ARDS: a retrospective cohort study

Aim: We hypothesized plasma sEH activity correlates with mortality in acute respiratory distress syndrome (ARDS) patients.Methods: Adult patients diagnosed with ARDS enrolled between 2017 and 2019 were included in this study.Results: A total of 337 adult patients met our inclusion criteria. Among them, 107 patients died within 28 days. The plasma sEH activity was higher in nonsurvivors relative to survivors. And a receiver operating characteristic curve with the area under the curve of 0.81 (95% confidence interval: 0.74-0.89) for the prediction of 28-day mortality was obtained. Its sensitivity and specificity were 72.5% and 74.6%, respectively.Conclusion: Elevated plasma sEH activity is associated with higher 28-day mortality in adult patients with ARDS.

Predictive value of gradient boosting decision trees for postoperative atelectasis complications in patients with pulmonary destruction

OBJECTIVE

To explore the application value of a gradient boosting decision tree (GBDT) in predicting postoperative atelectasis in patients with destroyed lungs.

METHODS

A total of 170 patients with damaged lungs who underwent surgical treatment in Chest Hospital of Guangxi Zhuang Autonomous Region from January 2021 to May 2023 were retrospectively selected. The patients were divided into a training set (n = 119) and a validation set (n = 51). Both GBDT algorithm model and Logistic regression model for predicting postoperative atelectasis in patients were constructed. The receiver operating characteristic (ROC) curve, calibration curve and decision curve were used to evaluate the prediction efficiency of the model.

RESULTS

The GBDT model indicated that the relative importance scores of the four influencing factors were operation time (51.037), intraoperative blood loss (38.657), presence of lung function (9.126) and sputum obstruction (1.180). Multivariate Logistic regression analysis revealed that operation duration and sputum obstruction were significant predictors of postoperative atelectasis among patients with destroyed lungs within the training set (P = 0.048, P = 0.002). The ROC curve analysis showed that the area under the curve (AUC) for GBDT and Logistic model in the training set was 0.795 and 0.763, and their AUCs in the validation set were 0.776 and 0.811. The GBDT model's predictions closely matched the ideal curve, showing a higher net benefit than the reference line.

CONCLUSIONS

GBDT model is suitable for predicting the incidence of complications in small samples.

Resistive spontaneous breathing exacerbated lipopolysaccharide-induced lung injury in mice

Background

Spontaneous respiratory mechanical force interacted with the primary lung injury and aggravated the progression of ARDS clinically. But the exact role and involved mechanism of it in the pathogenesis of ARDS animal model remained obscure.

Aim

This study was to investigate the effect of spontaneous respiratory mechanical force on lung injury of ARDS in mice.

Methods

Female C57BL/6 mice were subjected to resistive spontaneous breathing (RSB) by tracheal banding after 4-6 h of intranasal inhalation of LPS. Pulmonary function was examined by Buxco system, partial pressures of oxygen and carbon dioxide (PO2 and PCO2) were measured by a blood gas analyzer, and lung pathological changes were analyzed with hematoxylin and eosin staining. The levels of inflammatory markers were quantified by ELISA, total protein assay, and FACS analysis. The expression levels of mechanosensitive ion channels were detected by qRT-PCR and immunohistochemistry.

Results

The airway resistance (Raw) was increased and the tidal volume (TV) was decreased remarkedly in RSB group. RSB treatment did not affect PO2, PCO2, pathology and inflammation levels of lung in mice. The Raw increased and ventilatory indicators decreased in RSB + ARDS compared to ARDS significantly. Besides, RSB treatment deteriorated the changes of PO2, PCO2 and level of lactic acid induced by LPS. Meanwhile, RSB significantly promoted LPS-induced pulmonary histopathological injury, and elevated the levels of IL-1β, IL-6, TNF-α and total proteins, increased neutrophils infiltration. The expression level of Piezo1 in RSB + ARDS group was remarkably reduced compared to ARDS group and consistent with the severity of pulmonary damage.

Conclusion

RSB exacerbated LPS-induced ARDS hypoxemia and hypercapnia, inflammation and damage. The mechanosensitive protein Piezo1 expression decreased and may play an important role in the process.

Wnt5a-mediated autophagy contributes to the epithelial-mesenchymal transition of human bronchial epithelial cells during asthma

BACKGROUND

The epithelial-mesenchymal transition (EMT) of human bronchial epithelial cells (HBECs) is essential for airway remodeling during asthma. Wnt5a has been implicated in various lung diseases, while its role in the EMT of HBECs during asthma is yet to be determined. This study sought to define whether Wnt5a initiated EMT, leading to airway remodeling through the induction of autophagy in HBECs.

METHODS

Microarray analysis was used to investigate the expression change of WNT5A in asthma patients. In parallel, EMT models were induced using 16HBE cells by exposing them to house dust mites (HDM) or interleukin-4 (IL-4), and then the expression of Wnt5a was observed. Using in vitro gain- and loss-of-function approaches via Wnt5a mimic peptide FOXY5 and Wnt5a inhibitor BOX5, the alterations in the expression of the epithelial marker E-cadherin and the mesenchymal marker protein were observed. Mechanistically, the Ca2+/CaMKII signaling pathway and autophagy were evaluated. An autophagy inhibitor 3-MA was used to examine Wnt5a in the regulation of autophagy during EMT. Furthermore, we used a CaMKII inhibitor KN-93 to determine whether Wnt5a induced autophagy overactivation and EMT via the Ca2+/CaMKII signaling pathway.

RESULTS

Asthma patients exhibited a significant increase in the gene expression of WNT5A compared to the healthy control. Upon HDM and IL-4 treatments, we observed that Wnt5a gene and protein expression levels were significantly increased in 16HBE cells. Interestingly, Wnt5a mimic peptide FOXY5 significantly inhibited E-cadherin and upregulated α-SMA, Collagen I, and autophagy marker proteins (Beclin1 and LC3-II). Rhodamine-phalloidin staining showed that FOXY5 resulted in a rearrangement of the cytoskeleton and an increase in the quantity of stress fibers in 16HBE cells. Importantly, blocking Wnt5a with BOX5 significantly inhibited autophagy and EMT induced by IL-4 in 16HBE cells. Mechanistically, autophagy inhibitor 3-MA and CaMKII inhibitor KN-93 reduced the EMT of 16HBE cells caused by FOXY5, as well as the increase in stress fibers, cell adhesion, and autophagy.

CONCLUSION

This study illustrates a new link in the Wnt5a-Ca2+/CaMKII-autophagy axis to triggering airway remodeling. Our findings may provide novel strategies for the treatment of EMT-related diseases.

6-Gingerol ameliorates ulcerative colitis by inhibiting ferroptosis based on the integrative analysis of plasma metabolomics and network pharmacology

6-Gingerol (6-G), an active ingredient of ginger with anti-inflammation and anti-oxidation properties, can treat ulcerative colitis (UC). However, its underlying mechanism is still unclear. In this study, the pharmacodynamic evaluation of 6-G for treating UC was performed, and the mechanism of 6-G in ameliorating UC was excavated by plasma metabolomics and network pharmacology analysis, which was further validated by experimental and molecular docking. The results showed that 6-G could notably reduce diarrhea, weight loss, colonic pathological damage, and inflammation in UC mice. Plasma metabolomic results indicated that 6-G could regulate 19 differential metabolites, and its metabolic pathways mainly involved linoleic acid metabolism and arachidonic acid metabolism, which were closely associated with ferroptosis. Moreover, 60 potential targets for 6-G intervention on ferroptosis in UC were identified by network pharmacology, and enrichment analysis revealed that 6-G suppressed ferroptosis by modulating lipid peroxidation. Besides, the integration of metabolomics and network pharmacology showed that the regulation of 6-G on ferroptosis focused on 3 key targets, including ALOX5, ALOX15, and PTGS2. Further investigation indicated that 6-G significantly inhibited ferroptosis by decreasing iron load and malondialdehyde (MDA), and enhanced antioxidant capacity by reducing the content of glutathione disulfide (GSSG) and increasing the levels of superoxide dismutase (SOD) and glutathione (GSH) in UC mice and RSL3-induced Caco-2 cells. Furthermore, molecular docking showed the high affinity of 6-G with the identified 3 key targets. Collectively, this study elucidated the potential of 6-G in ameliorating UC by inhibiting ferroptosis. The integrated strategy also provided a theoretical basis for 6-G in treating UC.

Cardioprotective response and senescence in aged sEH null female mice exposed to LPS

Deterioration of physiological systems, like the cardiovascular system, occurs progressively with age impacting an individual's health and increasing susceptibility to injury and disease. Cellular senescence has an underlying role in age-related alterations and can be triggered by natural aging or prematurely by stressors such as the bacterial toxin lipopolysaccharide (LPS). The metabolism of polyunsaturated fatty acids by CYP450 enzymes produces numerous bioactive lipid mediators that can be further metabolized by soluble epoxide hydrolase (sEH) into diol metabolites, often with reduced biological effects. In our study, we observed age-related cardiac differences in female mice, where young mice demonstrated resistance to LPS injury, and genetic deletion or pharmacological inhibition of sEH using trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid attenuated LPS-induced cardiac dysfunction in aged female mice. Bulk RNA-sequencing analyses revealed transcriptomics differences in aged female hearts. The confirmatory analysis demonstrated changes to inflammatory and senescence gene markers such as Il-6, Mcp1, Il-1β, Nlrp3, p21, p16, SA-β-gal, and Gdf15 were attenuated in the hearts of aged female mice where sEH was deleted or inhibited. Collectively, these findings highlight the role of sEH in modulating the aging process of the heart, whereby targeting sEH is cardioprotective.NEW & NOTEWORTHY Soluble epoxide hydrolase (sEH) is an essential enzyme for converting epoxy fatty acids to their less bioactive diols. Our study suggests deletion or inhibition of sEH impacts the aging process in the hearts of female mice resulting in cardioprotection. Data indicate targeting sEH limits inflammation, preserves mitochondria, and alters cellular senescence in the aged female heart.

Targeting the TRAF3-ULK1-NLRP3 regulatory axis to control alveolar macrophage pyroptosis in acute lung injury

Acute lung injury (ALI) is a serious condition characterized by damage to the lungs. Recent research has revealed that activation of the NLRP3 inflammasome in alveolar macrophages, a type of immune cell in the lungs, plays a key role in the development of ALI. This process, known as pyroptosis, contributes significantly to ALI pathogenesis. Researchers have conducted comprehensive bioinformatics analyses and identified 15 key genes associated with alveolar macrophage pyroptosis in ALI. Among these, NLRP3 has emerged as a crucial regulator. This study further reveal that the ULK1 protein diminishes the expression of NLRP3, thereby reducing the immune response of alveolar macrophages and mitigating ALI. Conversely, TRAF3, another protein, is found to inhibit ULK1 through a process called ubiquitination, leading to increased activation of the NLRP3 inflammasome and exacerbation of ALI. This TRAF3-mediated suppression of ULK1 and subsequent activation of NLRP3 are confirmed through various in vitro and in vivo experiments. The presence of abundant M0 and M1 alveolar macrophages in the ALI tissue samples further support these findings. This research highlights the TRAF3-ULK1-NLRP3 regulatory axis as a pivotal pathway in ALI development and suggests that targeting this axis could be an effective therapeutic strategy for ALI treatment.

The STAT3 inhibitor B9 alleviates lipopolysaccharide-induced acute lung injury through its anti-inflammatory effects

The development of acute lung injury (ALI), a common respiratory condition with multiple causes, is significantly influenced by the pro-inflammatory environment of signal transducer and activator of transcription 3 (STAT3) in macrophages. Our study aimed to evaluate the anti-inflammatory effects of B9 (N-(4-hydroxyphenyl)-9, 10-dioxo-9, 10-dihydroanthracene-2-sulfonamide), a novel inhibitor targeting the STAT3 SH2 domain, in macrophages and to assess its therapeutic potential for ALI using a mouse model of lipopolysaccharide (LPS)-induced ALI. We found that B9 (30 mg/kg) significantly reduced lung pathological damage and neutrophil infiltration caused by the intratracheal administration of LPS. Additionally, the high expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in alveolar lavage fluid was also inhibited by B9 treatment. The decreased expression of CD86 and increased CD206 in lung tissue demonstrated the anti-inflammatory effect of B9, which was due to its inhibition of the STAT3 signaling pathway in macrophages of ALI mice. Furthermore, B9 suppressed the activation of RAW264.7 cells induced by LPS, characterized by its ability to inhibit the activation of iNOS and STAT3 in a dose-dependent manner, as well as reduce the secretion of IL-6 and IL-1β. The in vivo preliminary safety evaluation indicated that B9 had a favorable safety profile at the administered doses. These results suggest that B9 exerts a therapeutic effect on LPS-induced ALI, potentially by preventing the phosphorylation of STAT3 Y705 and S727 without affecting the STAT3 protein level. Taken together, these findings provide a foundation for developing B9 as a novel anti-inflammatory agent for ameliorating LPS-induced ALI.

Peficitinib alleviated acute lung injury by blocking glycolysis through JAK3/STAT3 pathway

Peficitinib is a selective Janus kinase (JAK3) inhibitor recently developed and approved for the treatment of rheumatoid arthritis in Japan. Glycolysis in macrophages could induce NOD-like receptor (NLR) family and pyrin domain-containing protein 3 (NLRP3) inflammasome activation, thus resulting in pyroptosis and acute lung injury (ALI). The aim of our study was to investigate whether Peficitinib could alleviate lipopolysaccharide (LPS)-induced ALI by inhibiting NLRP3 inflammasome activation. Wild type C57BL/6J mice were intraperitoneally injected with Peficitinib (5 or 10 mg·kg-1·day-1) for 7 consecutive days before LPS injection. The results showed that Peficitinib pretreatment significantly relieved LPS-induced pulmonary edema, inflammation, and apoptosis. NLRP3 inflammasome and glycolysis in murine lung tissues challenged with LPS were also blocked by Peficitinib. Furthermore, we found that the activation of JAK3/signal transducer and activator of transcription 3 (STAT3) was also suppressed by Peficitinib in mice with ALI. However, in Jak3 knockout mice, Peficitinib did not show obvious protective effects after LPS injection. In vitro experiments further showed that Jak3 overexpression completely abolished Peficitinib-elicited inhibitory effects on pyroptosis and glycolysis in LPS-induced RAW264.7 macrophages. Finally, we unveiled that LPS-induced activation of JAK3/STAT3 was mediated by toll-like receptor 4 (TLR4) in RAW264.7 macrophages. Collectively, our study proved that Peficitinib could protect against ALI by blocking JAK3-mediated glycolysis and pyroptosis in macrophages, which may serve as a promising candidate against ALI in the future.

Integrating network pharmacology and renal metabonomics to reveal the protective mechanism of resveratrol on gouty nephropathy

Resveratrol (Res) has been demonstrated to have beneficial effects on gouty nephropathy (GN). However, the mechanisms of Res on GN remain unclear. This study aimed to investigate the mechanisms of Res on GN. In this study, network pharmacology technology was used to predict the Res targets in the prevention and treatment of GN. Renal metabonomics was used to identify differential metabolites in kidney tissue of GN model rats. Finally, molecular docking technology was used to verify the binding ability of Res to key targets. Metabonomics analysis showed that 24 potentially important metabolites were involved in the prevention and treatment of GN with Res. After exposure to Res, metabolite levels normalized. The network pharmacology analysis showed that 24 key targets were involved in the prevention and treatment of GN disease. According to the metabolite-gene network diagram, we identified two core genes, PTGS1 and PTGS2, and found that both were involved in the arachidonic acid metabolism pathway. Molecular docking further verified the affinity of Res binding to PTGS1 and PTGS2. In conclusion, the mechanism of Res against GN may be the regulation of arachidonic acid metabolism through the regulation of PTGS 1 and PTGS 2.

Dynasore Alleviates LPS-Induced Acute Lung Injury by Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

Background

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are clinically severe respiratory disorders without available pharmacological therapies. Dynasore is a cell-permeable molecule that inhibits GTPase activity and exerts protective effects in several disease models. However, whether dynasore can alleviate lipopolysaccharide (LPS)-induced ALI is unknown. This study investigated the effect of dynasore on macrophage activation and explored its potential mechanisms in LPS-induced ALI in vitro and in vivo.

Methods

Bone marrow-derived macrophages (BMDMs) were activated classically with LPS or subjected to NLRP3 inflammasome activation with LPS+ATP. A mouse ALI model was established by the intratracheal instillation (i.t.) of LPS. The expression of PYD domains-containing protein 3 (NLRP3), caspase-1, and gasdermin D (GSDMD) protein was detected by Western blots. Inflammatory mediators were analyzed in the cell supernatant, in serum and bronchoalveolar lavage fluid (BALF) by enzyme-linked immunosorbent assays. Morphological changes in lung tissues were evaluated by hematoxylin and eosin staining. F4/80, Caspase-1 and GSDMD distribution in lung tissue was detected by immunofluorescence.

Results

Dynasore downregulated nuclear factor (NF)-κB signaling and reduced proinflammatory cytokine production in vitro and inhibited the production and release of interleukin (IL)-1β, NLRP3 inflammasome activation, and macrophage pyroptosis through the Drp1/ROS/NLRP3 axis. Dynasore significantly reduced lung injury scores and proinflammatory cytokine levels in both BALF and serum in vivo, including IL-1β and IL-6. Dynasore also downregulated the co-expression of F4/80, caspase-1 and GSDMD in lung tissue.

Conclusion

Collectively, these findings demonstrated that dynasore could alleviate LPS-induced ALI by regulating macrophage pyroptosis, which might provide a new therapeutic strategy for ALI/ARDS.

Role of soluble epoxide hydrolase in pain and depression comorbidity

The coexistence of chronic pain and depression in clinical practice places a substantial social burden and profoundly impacts in patients. Although a clear correlation exists, the underlying mechanism of comorbidity between chronic pain and depression remains elusive. Research conducted in recent decades has uncovered that soluble epoxide hydrolase, a pivotal enzyme in the metabolism of polyunsaturated fatty acids, plays a crucial role in inflammation. Interestingly, this enzyme is intricately linked to the development of both pain and depression. With this understanding, this review aims to summarize the roles of soluble epoxide hydrolase in pain, depression, and their comorbidity. Simultaneously, we will also explore the underlying mechanisms, providing guidance for future research and drug development.

Causal relationship between particulate matter and COVID-19 risk: A mendelian randomization study

Background

Observational studies have linked exposure to fine (PM2.5) and coarse (PM10) particulate matter air pollution with adverse COVID-19 outcomes, including higher incidence and mortality. However, some studies questioned the effect of air pollution on COVID-19 susceptibility, raising questions about the causal nature of these associations. To address this, a less biased method like Mendelian randomization (MR) is utilized, which employs genetic variants as instrumental variables to infer causal relationships in observational data.

Method

We performed two-sample MR analysis using public genome-wide association studies data. Instrumental variables correlated with PM2.5 concentration, PM2.5 absorbance, PM2.5-10 concentration and PM10 concentration were identified. The inverse variance weighted (IVW), robust adjusted profile score (RAPS) and generalized summary data-based Mendelian randomization (GSMR) methods were used for analysis.

Results

IVW MR analysis showed PM2.5 concentration [odd ratio (OR) = 3.29, 95% confidence interval (CI) 1.48-7.35, P-value = 0.0036], PM2.5 absorbance (OR = 5.62, 95%CI 1.98-15.94, P-value = 0.0012), and PM10 concentration (OR = 3.74, 95%CI 1.52-9.20, P-value = 0.0041) increased the risk of COVID-19 severity after Bonferroni correction. Further validation confirmed PM2.5 absorbance was associated with heightened COVID-19 severity (OR = 6.05, 95%CI 1.99-18.38, P-value = 0.0015 for RAPS method; OR = 4.91, 95%CI 1.65-14.59, P-value = 0.0042 for GSMR method) and hospitalization (OR = 3.15, 95%CI 1.54-6.47, P-value = 0.0018 for RAPS method). No causal links were observed between particulate matter exposure and COVID-19 susceptibility.

Conclusions

Our study established a causal relationship between smaller particle pollution, specifically PM2.5, and increased risk of COVID-19 severity and hospitalization. These findings highlight the importance of improving air quality to mitigate respiratory disease progression.

NLRP3 knockout in mice provided protection against Serratia marcescens-induced acute pneumonia by decreasing PD-L1 and PD-1 expression in macrophages

Antibiotic-resistant Serratia marcescens (Sm) is known to cause bloodstream infections, pneumonia, etc. The nod-like receptor family, pyrin domain-containing 3 (NLRP3), has been implicated in various lung infections. Yet, its role in Sm-induced pneumonia was not well understood. In our study, we discovered that deletion of Nlrp3 in mice significantly improved Sm-induced survival rates, reduced bacterial loads in the lungs, bronchoalveolar lavage fluid (BALF), and bloodstream, and mitigated the severity of acute lung injury (ALI) compared to wild-type (WT) mice. Mechanistically, we observed that 24 h post-Sm infection, NLRP3 inflammasome activation occurred, leading to gasdermin D NH2-terminal (GSDMD-NT)-induced pyroptosis in macrophages and IL-1β secretion. The NLRP3 or NLRP3 inflammasome influenced the expression PD-L1 and PD-1, as well as the count of PD-L1 or PD-1-expressing macrophages, alveolar macrophages, interstitial macrophages, PD-L1-expressing neutrophils, and the count of macrophage receptors with collagenous structure (MARCO)-expressing macrophages, particularly MARCO+ alveolar macrophages. The frequency of MARCO+ alveolar macrophages, PD-1 expression, particularly PD-1+ interstitial macrophages were negatively or positively correlated with the Sm load, respectively. Additionally, IL-1β levels in BALF correlated with three features of acute lung injury: histologic score, protein concentration and neutrophil count in BALF. Consequently, our findings suggest that Nlrp3 deletion offers protection agaisnt acute Sm pneumonia in mice by inhibiting inflammasome activation and reducing Sm infection-induced PD-L1/PD-1 or MARCO expression, particularly in macrophages. This highlights potential therapeutic targets for Sm and other gram-negative bacteria-induced acute pneumonia.

S100A9-/- alleviates LPS-induced acute lung injury by regulating M1 macrophage polarization and inhibiting pyroptosis via the TLR4/MyD88/NFκB signaling axis

Acute lung injury (ALI) is characterized by pulmonary diffusion abnormalities that may progress to multiple-organ failure in severe cases. There are limited effective treatments for ALI, which makes the search for new therapeutic avenues critically important. Macrophages play a pivotal role in the pathogenesis of ALI. The degree of macrophage polarization is closely related to the severity and prognosis of ALI, and S100A9 promotes M1 polarization of macrophages. The present study assessed the effects of S100A9-gene deficiency on macrophage polarization and acute lung injury. Our cohort study showed that plasma S100A8/A9 levels had significant diagnostic value for pediatric pneumonia and primarily correlated with monocyte-macrophages and neutrophils. We established a lipopolysaccharide (LPS)-induced mouse model of acute lung injury and demonstrated that knockout of the S100A9 gene mitigated inflammation by suppressing the secretion of pro-inflammatory cytokines, reducing the number of inflammatory cells in the bronchoalveolar lavage fluid, and inhibiting cell apoptosis, which ameliorated acute lung injury in mice. The in vitro and in vivo mechanistic studies demonstrated that S100A9-gene deficiency inhibited macrophage M1 polarization and reduced the levels of pulmonary macrophage chemotactic factors and inflammatory cytokines by suppressing the TLR4/MyD88/NF-κB signaling pathway and reversing the expression of the NLRP3 pyroptosis pathway, which reduced cell death. In conclusion, S100A9-gene deficiency alleviated LPS-induced acute lung injury by inhibiting macrophage M1 polarization and pyroptosis via the TLR4/MyD88/NFκB pathway, which suggests a potential therapeutic strategy for the treatment of ALI.

COX-2/sEH-Mediated Macrophage Activation Is a Target for Pulmonary Protection in Mouse Models of Chronic Obstructive Pulmonary Disease

Effective inhibition of macrophage activation is critical for resolving inflammation and restoring pulmonary function in patients with chronic obstructive pulmonary disease (COPD). In this study, we identified the dual-enhanced cyclooxygenase-2 (COX-2)/soluble epoxide hydrolase (sEH) as a novel regulator of macrophage activation in COPD. Both COX-2 and sEH were found to be increased in patients and mice with COPD and in macrophages exposed to cigarette smoke extract. Pharmacological reduction of the COX-2 and sEH by 4-(5-phenyl-3-{3-[3-(4-trifluoromethylphenyl)-ureido]-propyl}-pyrazol-1-yl)-benzenesulfonamide (PTUPB) effectively prevented macrophage activation, downregulated inflammation-related genes, and reduced lung injury, thereby improving respiratory function in a mouse model of COPD induced by cigarette smoke and lipopolysaccharide. Mechanistically, enhanced COX-2/sEH triggered the activation of the NACHT, LRR, and PYD domains-containing protein 3 inflammasome, leading to the cleavage of pro-IL-1β into its active form in macrophages and amplifying inflammatory responses. These findings demonstrate that targeting COX-2/sEH-mediated macrophage activation may be a promising therapeutic strategy for COPD. Importantly, our data support the potential use of the dual COX-2 and sEH inhibitor PTUPB as a therapeutic drug for the treatment of COPD.

Inhibition of Soluble Epoxide Hydrolase Reduces Inflammation and Myocardial Injury in Arrhythmogenic Cardiomyopathy

Previous studies have implicated persistent innate immune signaling in the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a familial non-ischemic heart muscle disease characterized by life-threatening arrhythmias and progressive myocardial injury. Here, we provide new evidence implicating inflammatory lipid autocoids in ACM. We show that specialized pro-resolving lipid mediators are reduced in hearts of Dsg2mut/mut mice, a well characterized mouse model of ACM. We also found that ACM disease features can be reversed in rat ventricular myocytes expressing mutant JUP by the pro-resolving epoxy fatty acid (EpFA) 14,15-eicosatrienoic acid (14-15-EET), whereas 14,15-EE-5(Z)E which antagonizes actions of the putative 14,15-EET receptor, intensified nuclear accumulation of the desmosomal protein plakoglobin. Soluble epoxide hydrolase (sEH), an enzyme that rapidly converts pro-resolving EpFAs into polar, far less active or even pro-inflammatory diols, is highly expressed in cardiac myocytes in Dsg2mut/mut mice. Inhibition of sEH prevented progression of myocardial injury in Dsg2mut/mut mice and led to recovery of contractile function. This was associated with reduced myocardial expression of genes involved in the innate immune response and fewer pro-inflammatory macrophages expressing CCR2, which mediate myocardial injury in Dsg2mut/mut mice. These results suggest that pro-inflammatory eicosanoids contribute to the pathogenesis of ACM and, further, that inhibition of sEH may be an effective, mechanism-based therapy for ACM patients.

Circular RNA circVAPA modulates macrophage pyroptosis in sepsis-induced acute lung injury through targeting miR-212-3p/Sirt1/Nrf2/NLRP3 axis

Sepsis-induced acute lung injury (ALI) is an inflammatory condition involving the pyroptosis of macrophages. This study investigated the role of circular RNA hsa_circ_0006990 (circVAPA) in regulating macrophage pyroptosis in ALI and the underlying mechanisms. The expression pattern of circVAPA was examined in the mouse model of ALI and in the LPS-treated RAW264.7 macrophage cell line. Lung tissue damage was evaluated by haematoxylin and eosin staining, immunohistochemistry and a myeloperoxidase activity assay. The molecular mechanisms were investigated by luciferase reporter assay, western blot, RT-qPCR and ELISA. circVAPA was down-regulated in the lung tissues of ALI mice and LPS-induced RAW264.7 cells. circVAPA over-expression alleviated lung tissue injury and dampened LPS-induced pyroptosis and Th17-associated inflammatory responses. miR-212-3p was identified as a target of circVAPA, and miR-212-3p negatively regulated the expression of Sirt1. Sirt1 knockdown largely abolished the effect of circVAPA over-expression on pyroptosis. CircVAPA/miR-212-3p/Sirt1 axis also regulates Nrf2 and NLRP3 expression upon LPS challenge. By targeting miR-212-3p, circVAPA over-expression negatively regulates the expression of Sirt1 and pyroptosis-related factors (Nrf2 and NLRP3), which alleviates the inflammatory damages in sepsis-induced ALI.

CGRP is essential for protection against alveolar epithelial cell necroptosis by activating the AMPK/L-OPA1 signaling pathway during acute lung injury

Alveolar epithelial cell (AEC) necroptosis is critical to disrupt the alveolar barrier and provoke acute lung injury (ALI). Here, we define calcitonin gene-related peptide (CGRP), the most abundant endogenous neuropeptide in the lung, as a novel modulator of AEC necroptosis in lipopolysaccharide (LPS)-induced ALI. Upon LPS-induced ALI, overexpression of Cgrp significantly mitigates the inflammatory response, alleviates lung tissue damage, and decreases AEC necroptosis. Similarly, CGRP alleviated AEC necroptosis under the LPS challenge in vitro. Previously, we identified that long optic atrophy 1 (L-OPA1) deficiency mediates mitochondrial fragmentation, leading to AEC necroptosis. In this study, we discovered that CGRP positively regulated mitochondrial fusion through stabilizing L-OPA1. Mechanistically, we elucidate that CGRP activates AMP-activated protein kinase (AMPK). Furthermore, the blockade of AMPK compromised the protective effect of CGRP against AEC necroptosis following the LPS challenge. Our study suggests that CRGP-mediated activation of the AMPK/L-OPA1 axis may have potent therapeutic benefits for patients with ALI or other diseases with necroptosis.

MiR-2113 overexpression attenuates sepsis-induced acute pulmonary dysfunction, inflammation and fibrosis by inhibition of HMGB1

Purpose

Sepsis-induced acute lung injury is related to high mortality. MiR-2113 possesses important functions in human diseases. This research aimed to clarify the role and mechanism of miR-2113 in sepsis-induced acute lung injury.

Methods

The expression of miR-2113 in lipopolysaccharide (LPS)-induced MLE-12 cells, serum of sepsis patients, and cecal ligation and puncture mouse models was examined using quantitative real-time PCR. The functions of miR-2113 in LPS-treated MLE-12 cells were estimated by Cell Counting Kit-8 assay, flow cytometry, enzyme-linked immunosorbent assay, Western blot, and immunofluorescence. The influences of miR-2113 in cecal ligation and puncture-induced acute lung injury in mice were assessed by hematoxylin-eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay, acute pulmonary dysfunction analysis, lactate dehydrogenase levels and total protein concentrations in bronchoalveolar lavage fluid, and Masson staining. Also, the mechanism of miR-2113 was examined using a dual-luciferase reporter assay.

Results

MiR-2113 expression was decreased in LPS-induced MLE-12 cells, serum of sepsis patients, and cecal ligation and puncture mouse models. miR-2113 overexpression restored LPS-reduced MLE-12 cell proliferation, but alleviated LPS-induced apoptosis and markers of inflammation and fibrosis in MLE-12 cells. Moreover, we found that miR-2113 mimic reduced LPS-induced MLE-12 cell injury by negatively regulating high-mobility group box 1. In vivo data further confirmed that miR-2113 overexpression alleviated acute pulmonary dysfunction, inflammation and fibrosis in cecal ligation and puncture-induced sepsis mice.

Conclusion

MiR-2113 relieved sepsis-induced acute pulmonary dysfunction, inflammation and fibrosis through decreasing high-mobility group box 1.

Bazi Bushen capsule improves the deterioration of the intestinal barrier function by inhibiting NLRP3 inflammasome-mediated pyroptosis through microbiota-gut-brain axis

Purpose

The senescence-accelerated prone mouse 8 (SAMP8) is a widely used model for accelerating aging, especially in central aging. Mounting evidence indicates that the microbiota-gut-brain axis may be involved in the pathogenesis and progression of central aging-related diseases. This study aims to investigate whether Bazi Bushen capsule (BZBS) attenuates the deterioration of the intestinal function in the central aging animal model.

Methods

In our study, the SAMP8 mice were randomly divided into the model group, the BZ-low group (0.5 g/kg/d BZBS), the BZ-high group (1 g/kg/d BZBS) and the RAPA group (2 mg/kg/d rapamycin). Age-matched SAMR1 mice were used as the control group. Next, cognitive function was detected through Nissl staining and two-photon microscopy. The gut microbiota composition of fecal samples was analyzed by 16S rRNA gene sequencing. The Ileum tissue morphology was observed by hematoxylin and eosin staining, and the intestinal barrier function was observed by immunofluorescence. The expression of senescence-associated secretory phenotype (SASP) factors, including P53, TNF-α, NF-κB, IL-4, IL-6, and IL-10 was measured by real-time quantitative PCR. Macrophage infiltration and the proliferation and differentiation of intestinal cells were assessed by immunohistochemistry. We also detected the inflammasome and pyroptosis levels in ileum tissue by western blotting.

Results

BZBS improved the cognitive function and neuronal density of SAMP8 mice. BZBS also restored the intestinal villus structure and barrier function, which were damaged in SAMP8 mice. BZBS reduced the expression of SASP factors and the infiltration of macrophages in the ileum tissues, indicating a lower level of inflammation. BZBS enhanced the proliferation and differentiation of intestinal cells, which are essential for maintaining intestinal homeostasis. BZBS modulated the gut microbiota composition, by which BZBS inhibited the activation of inflammasomes and pyroptosis in the intestine.

Conclusion

BZBS could restore the dysbiosis of the gut microbiota and prevent the deterioration of intestinal barrier function by inhibiting NLRP3 inflammasome-mediated pyroptosis. These results suggested that BZBS attenuated the cognitive aging of SAMP8 mice, at least partially, by targeting the microbiota-gut-brain axis.

Epoxyeicosatrienoic acids alleviate alveolar epithelial cell senescence by inhibiting mitophagy through NOX4/Nrf2 pathway

Alveolar epithelial cell (AEC) senescence is considered to be a universal pathological feature of many chronic pulmonary diseases. Our previous study found that epoxyeicosatrienoic acids (EETs), produced from arachidonic acid (ARA) through the cytochrome P450 cyclooxygenase (CYP) pathway, have significant negative regulatory effects on cellular senescence in AECs. However, the exact mechanisms by which EETs alleviate the senescence of AECs still need to be further explored. In the present study, we observed that bleomycin (BLM) induced enhanced mitophagy accompanied by increased mitochondrial ROS (mito-ROS) content in the murine alveolar epithelial cell line MLE12. While EETs reduced BLM-induced mitophagy and mito-ROS content in MLE12 cells, and the mechanism was related to the regulation of NOX4/Nrf2-mediated redox imbalance. Furthermore, we found that inhibition of EETs degradation could significantly inhibit mitophagy and regulate NOX4/Nrf2 balance to exert anti-oxidant effects in D-galactose-induced premature aging mice. Collectively, these findings may provide new ideas for treating age-related pulmonary diseases by targeting EETs to improve mitochondrial dysfunction and reduce oxidative stress.

Crosstalk between neutrophil extracellular traps and immune regulation: insights into pathobiology and therapeutic implications of transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated death, occurring during or within 6 hours after transfusion. Reports indicate that TRALI can be categorized as having or lacking acute respiratory distress syndrome (ARDS) risk factors. There are two types of TRALI in terms of its pathogenesis: antibody-mediated and non-antibody-mediated. The key initiation steps involve the priming and activation of neutrophils, with neutrophil extracellular traps (NETs) being established as effector molecules formed by activated neutrophils in response to various stimuli. These NETs contribute to the production and release of reactive oxygen species (ROS) and participate in the destruction of pulmonary vascular endothelial cells. The significant role of NETs in TRALI is well recognized, offering a potential pathway for TRALI treatment. Moreover, platelets, macrophages, endothelial cells, and complements have been identified as promoters of NET formation. Concurrently, studies have demonstrated that the storage of platelets and concentrated red blood cells (RBC) can induce TRALI through bioactive lipids. In this article, recent clinical and pre-clinical studies on the pathophysiology and pathogenesis of TRALI are reviewed to further illuminate the mechanism through which NETs induce TRALI. This review aims to propose new therapeutic strategies for TRALI, with the hope of effectively improving its poor prognosis.

S14G-humanin alleviates acute lung injury by inhibiting the activation of NF-κB

Acute lung injury (ALI) is characterized by severely damaged alveoli and blood vessels, seriously affecting the health of patients and causing a high mortality rate. The pathogenesis of ALI is complex, with inflammatory reactions and oxidative stress (OS) mainly involved. S14G humanin (HNG) is derived from humanin (HN), which is claimed with promising anti-inflammatory functions. Herein, the protective influence of HNG on ALI will be explored in a mouse model. The ALI model was established in mice via intratracheal instillation of 3 mg/kg LPS, followed by an intraperitoneal injection of 3 and 6 mg/kg HNG, respectively. Thicker alveolar walls, aggravated neutrophil infiltration, and increased wet weight/dry weight (W/D) ratio were observed in ALI mice, accompanied by an aggravated apoptotic state, all of which were notably alleviated by HNG. Furthermore, increased number of total cells and neutrophils in bronchoalveolar lavage fluid (BALF), elevated secretion of inflammatory cytokines, enhanced reactive oxygen species (ROS) and Malondialdehyde (MDA) levels, and declined superoxide dismutase-2 (SOD2) levels were observed in ALI mice, which were markedly ameliorated by HNG. Moreover, the upregulated levels of NOD-like receptor family pyrin domain containing 3 (NLRP3), caspase-1, and caspases cleave gasdermin D N/caspases cleave gasdermin D FL (GSDMD N/GSDMD FL) in ALI mice were signally repressed by HNG. Lastly, the upregulation of Toll-like receptor 4 (TLR4) and p-p65/p65, and downregulation of IκB-α observed in ALI mice were sharply reversed by HNG. Collectively, HNG alleviated the ALI in mice by inhibiting the activation of nuclear factor kappa B (NF-κB) signaling.

TMEM16A deficiency in alveolar type 2 epithelial cells protected against endoplasmic reticulum stress-induced ferroptosis during acute lung injury

Transmembrane protein 16A (TMEM16A) is one of the members of the ten-member family of "transmembrane protein 16", playing critical roles in infection and solid organ injury. Acute lung injury (ALI) is a devastating disease which could be triggered by sepsis, trauma, and ischemia reperfusion. However, molecular mechanisms contributing to ALI are poorly understood at presently. In this study, we investigated the role of TMEM16A in sepsis-induced ALI using TMEM16A-deficient mice. Sepsis-induced ALI model was established by intratracheal injection of lipopolysaccharide (LPS). Our results showed that LPS stimulation significantly upregulated the expression levels of TMEM16A in lung tissues and in alveolar epithelial type II (AT2) cells. Knockout of TMEM16A in AT2 cells significantly improved pulmonary function and alleviated lung pathological injury in LPS-treated mice. Meanwhile, TMEM16A deficiency also inhibited endoplasmic reticulum (ER) stress and ferroptosis in AT2 cells from LPS-treated mice. In vitro experiments further demonstrated that ER stress and ferroptosis were inhibited after TMEM16A was knocked out. Furthermore, we used ER stress inducer thapsigargin to induce ER stress in TMEM16A-null AT2 cells and found that the induction of ER stress abolished the inhibition of ferroptosis by TMEM16A deficiency in LPS-treated AT2 cells. Finally, we disclosed that pharmacological inhibition of TMEM16A by shikonin also showed similar therapeutic effect on LPS-induced ALI in vivo. In conclusion, TMEM16A deficiency in AT2 cells could alleviate sepsis-induced ALI by decreasing ER stress-induced ferroptosis during ALI.

Quercetin alleviates lipopolysaccharide‑induced acute lung injury by inhibiting ferroptosis via the Sirt1/Nrf2/Gpx4 pathway

Acute lung injury (ALI) causes high morbidity and mortality rates in critically ill patients, and there are currently no effective therapeutic drugs. Ferroptosis is a newly discovered mode of regulated cell death that contributes to the progression of ALI. Quercetin possesses anti‑inflammatory and antioxidant properties. However, whether quercetin can protect against lipopolysaccharide (LPS)‑induced ALI by inhibiting ferroptosis and its underlying mechanisms remains unclear. The present study evaluated the protective effects of quercetin and underlying molecular mechanisms in LPS‑induced ALI by establishing an ALI mouse model and an alveolar epithelial cell injury model via treatment of the mice or alveolar epithelial cells with LPS. Mouse lung injury was assessed by evaluating the histological lung injury score, bronchoalveolar lavage fluid cell count and inflammatory cytokine levels; alveolar epithelial cell injury was assessed by Cell counting kit‑8, lactate dehydrogenase and EDU assays; and ferroptosis was assessed by detecting the changes in the levels of malondialdehyde, glutathione, iron, glutathione peroxidase 4 (Gpx4) and 4‑hydroxynonenal in vivo and vitro. The present study indicated that quercetin effectively ameliorated LPS‑induced ALI in the mouse model by reducing histopathological changes, proinflammatory cytokine release and reactive oxygen species generation and inhibiting ferroptosis. Quercetin significantly decreased ferroptosis and improved the proliferative ability of LPS‑treated alveolar epithelial cells. Additionally, it was demonstrated that quercetin markedly enhanced the alveolar epithelial barrier, as evidenced by the upregulation of tight junction protein expression both in vivo and in vitro. Mechanistically, quercetin effectively activated the sirtuin 1 (Sirt1)/nuclear factor erythroid 2‑related factor 2 (Nrf2)/Gpx4 signaling pathway, and targeted in vivo inhibition or in vitro knockdown of Sirt1 significantly reduced the anti‑ferroptotic functions of quercetin. In conclusion, the results demonstrated that quercetin exerts its therapeutic effects against LPS‑induced ALI by inhibiting ferroptosis via the activation of the Sirt1/Nrf2/Gpx4 signaling pathway.

Bisdemethoxycurcumin alleviates LPS-induced acute lung injury via activating AMPKα pathway

OBJECTIVE

Inflammation and oxidative stress contribute to the pathogenesis of acute lung injury (ALI), and subsequently result in rapid deterioration in health. Considering the indispensable role of bisdemethoxycurcumin (BDMC) in inflammation and oxidative stress, the present study aims to examine the effect of BDMC on sepsis-related ALI.

METHODS

C57BL/6 mice were administered with BDMC (100 mg/kg) or an equal volume of vehicle, and then injected with lipopolysaccharides (LPS) to induce ALI. We assessed the parameters of lung injury, inflammatory response and oxidative stress in lung tissues. Consistently, the macrophages with or without BDMC treatment were exposed to LPS to verify the effect of BDMC in vitro.

RESULTS

BDMC suppressed LPS-induced lung injury, inflammation and oxidative stress in vivo and in vitro. Mechanistically, BDMC increased the phosphorylation of AMPKα in response to LPS stimulation, and AMPK inhibition with Compound C almost completely blunted the protective effect of BDMC in LPS-treated mice and macrophages. Moreover, we demonstrated that BDMC activated AMPKα via the cAMP/Epac pathway.

CONCLUSION

Our study identifies the protective effect of BDMC against LPS-induced ALI, and the underlying mechanism may be related to the activation of cAMP/Epac/AMPKα signaling pathway.

Lipopolysaccharide promotes NLRP3 inflammasome activation by inhibiting TFEB-mediated autophagy in NRK-52E cells

The NLRP3 inflammasome is involved in many inflammatory diseases. Its activity must be strictly controlled to alleviate the inflammatory process. Autophagy plays a protective role in the negative regulation of NLRP3 inflammasome activation. However, the regulatory mechanism of autophagy controlling NLRP3 inflammasome activation remains to be further investigated. Here, we showed that in NRK-52E cells, lipopolysaccharide (LPS) and ATP stimulation significantly decreased mitochondrial membrane potential, increased ROS production and mtDNA copy number in cytosol. Moreover, autophagic flux was blocked when challenged with LPS and ATP as evidenced by increased LC3 II and p62 expression, reduced TFEB and CTSD expression, and impaired lysosomal acid environment. Furthermore, TFEB deficiency increased cytosolic mtDNA and enhanced LPS and ATP induced NLRP3 inflammasome activation and proinflammatory cytokine expression. Taken together, these findings reveal that LPS and ATP stimulation promoted NLRP3 inflammasome activation through inhibiting TFEB-mediated autophagy in NRK-52E cells, and TFEB could be a potential therapeutic target for the treatment of NLRP3 inflammasome-related kidney diseases.

Trans-anethole pretreatment ameliorates hepatic ischemia-reperfusion injury via regulation of soluble epoxide hydrolase

Hepatic ischemia reperfusion injury (IRI) is a risk factor for early graft nonfunction and graft rejection after liver transplantation (LT). The process of liver IRI involves inflammatory response, oxidative stress, apoptosis and other pathophysiological processes. So far, there is still a lack of effective drugs to ameliorate liver IRI. Trans-anethole (TA) is an aromatic compound. Many medications as well as natural foods contain TA. TA has multiple effects such as anti-inflammation, anti-oxidative stress and anti-apoptosis. However, the mechanism of TA pretreatment in liver IRI is unclear. The mice hepatic IRI model was constructed after gavage pretreatment with TA (10 mg/kg, 20 mg/kg, 40 mg/kg) for 7 consecutive days. Our study confirmed that TA pretreatment significantly improve liver function and reduce serum AST, ALT in hepatic IRI. HE staining showed that TA pretreatment alleviated liver injury. Meanwhile, TA (20 mg/kg) pretreatment attenuated hepatocyte apoptosis in hepatic IRI. In addition, TA (20 mg/kg) pretreatment reduced the inflammatory factors TNF-α, IL-6 and infiltration of CD11b positive cells in liver tissues during hepatic IRI in mice. TA pretreatment also alleviated oxidative stress in mice hepatic IRI. Our study further indicated that TA pretreatment attenuated mice hepatic IRI through inhibiting NLRP3 inflammasome activation via regulation of soluble epoxide hydrolase (sEH). This study provides a novel and effective potential drug with few side effects for easing liver IRI.

Co-delivery of azithromycin and ibuprofen by ROS-responsive polymer nanoparticles synergistically attenuates the acute lung injury

Bacterial infection causes lung inflammation and recruitment of several inflammatory factors that may result in acute lung injury (ALI). During bacterial infection, reactive oxygen species (ROS) and other signaling pathways are activated, which intensify inflammation and increase ALI-related mortality and morbidity. To improve the ALI therapy outcome, it is imperative clinically to manage bacterial infection and excessive inflammation simultaneously. Herein, a synergistic nanoplatform (AZI+IBF@NPs) constituted of ROS-responsive polymers (PFTU), and antibiotic (azithromycin, AZI) and anti-inflammatory drug (ibuprofen, IBF) was developed to enable an antioxidative effect, eliminate bacteria, and modulate the inflammatory milieu in ALI. The ROS-responsive NPs (PFTU NPs) loaded with dual-drugs (AZI and IBF) scavenged excessive ROS efficiently both in vitro and in vivo. The AZI+IBF@NPs eradicated Pseudomonas aeruginosa (PA) bacterial strain successfully. To imitate the entry of bacterial-derived compounds in body, a lipopolysaccharide (LPS) model was adopted. The administration of AZI+IBF@NPs via the tail veins dramatically reduced the number of neutrophils, significantly reduced cell apoptosis and total protein concentration in vivo. Furthermore, nucleotide oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3) and Interleukin-1 beta (IL-1β) expressions were most effectively inhibited by the AZI+IBF@NPs. These findings present a novel nanoplatform for the effective treatment of ALI.

HOXD9 is a potential prognostic biomarker involved in immune microenvironment of glioma

BACKGROUND

Glioma is the prevailing malignant tumor affecting the brain and central nervous system, constituting over 80% of all malignant brain tumors. HOXD9 has been implicated in the development of glioma, but the specific mechanism of its influence on glioma pathogenesis remains incompletely understood. The purpose of this study was to investigate the role of HOXD9 in glioma and examine the changes in HOXD9 expression during the progression of glioma, thus contributing new insights into the pathogenesis of glioma.

METHODS

Glioma samples from the Cancer Gene Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) datasets were included in this study. Variations in HOXD9 expression in gliomas between different subgroups of multiple clinical characteristics were explored, and the expression was validated in glioma samples using qRT-PCR and western blotting. Next, the impact of HOXD9 on the prognosis of gliomas was explored by survival analysis, receiver operating characteristic curve, and nomogram plots. Subsequently, the association between HOXD9 and the tumor immune microenvironment was explored using the ssGSEA algorithm and the ESTIMATE algorithm. Then, immune-related pathways associated with HOXD9 were determined by differential express analysis and GSEA. Finally, HOXD9-related genomic alterations were identified.

RESULTS

HOXD9 expression is upregulated and correlated with malignant properties in glioma. Similarly, our validation results showed significantly upregulated protein and mRNA levels of HOXD9 in glioma brain tissues. In addition, high HOXD9 expression was indicative of a poor prognosis for glioma patients. Additionally, elevated HOXD9 levels were associated with reduced tumor purity and higher levels of immune invasion. Finally, HOXD9 was significantly associated with genomic alterations.

CONCLUSION

Overall, this study has unveiled a significant association between HOXD9 and the prognosis and survival of glioma patients. Our findings highlight the potential of HOXD9 as a prognostic biomarker, implicating its role in influencing the glioma immune microenvironment.

Soluble epoxide hydrolase deficiency attenuates airway inflammation in COPD via IRE1α/JNK/AP-1 signaling pathway

BACKGROUND

Soluble Epoxide Hydrolase (sEH) metabolizes anti-inflammatory epoxyeicosatrienoic acids and critically affects airway inflammation in chronic obstructive pulmonary disease (COPD). Considering the excessive endoplasmic reticulum stress is associated with the earlier onset of COPD. The role of sEH and endoplasmic reticulum stress in the pathogenesis of COPD remains unknown.

METHOD

16 weeks of cigarette-exposed mice were used to detect the relationship between sEH and endoplasmic reticulum stress in COPD. Human epithelial cells were used in vitro to determine the regulation mechanism of sEH in endoplasmic reticulum stress induced by cigarette smoke.

RESULTS

sEH deficiency helps reduce emphysema formation after smoke exposure by alleviating endoplasmic reticulum stress response. sEH deficiency effectively reverses the upregulation of phosphorylation IRE1α and JNK and the nuclear expression of AP-1, alleviating the secretion of inflammatory factors induced by cigarette smoke extract. Furthermore, the treatment with endoplasmic reticulum stress and IRE1α inhibitor downregulated cigarette smoke extract-induced sEH expression and the secretion of inflammatory factors.

CONCLUSION

sEH probably alleviates airway inflammatory response and endoplasmic reticulum stress via the IRE1α/JNK/AP-1 pathway, which might attenuate lung injury caused by long-term smoking and provide a new pharmacological target for preventing and treating COPD.

Saharan dust induces NLRP3-dependent inflammatory cytokines in an alveolar air-liquid interface co-culture model

BACKGROUND

Epidemiological studies have related desert dust events to increased respiratory morbidity and mortality. Although the Sahara is the largest source of desert dust, Saharan dust (SD) has been barely examined in toxicological studies. Here, we aimed to assess the NLRP3 inflammasome-caspase-1-pathway-dependent pro-inflammatory potency of SD in comparison to crystalline silica (DQ12 quartz) in an advanced air-liquid interface (ALI) co-culture model. Therefore, we exposed ALI co-cultures of alveolar epithelial A549 cells and macrophage-like differentiated THP-1 cells to 10, 21, and 31 µg/cm² SD and DQ12 for 24 h using a Vitrocell Cloud system. Additionally, we exposed ALI co-cultures containing caspase (CASP)1-/- and NLRP3-/- THP-1 cells to SD.

RESULTS

Characterization of nebulized DQ12 and SD revealed that over 90% of agglomerates of both dusts were smaller than 2.5 μm. Characterization of the ALI co-culture model revealed that it produced surfactant protein C and that THP-1 cells remained viable at the ALI. Moreover, wild type, CASP1-/-, and NLRP3-/- THP-1 cells had comparable levels of the surface receptors cluster of differentiation 14 (CD14), toll-like receptor 2 (TLR2), and TLR4. Exposing ALI co-cultures to non-cytotoxic doses of DQ12 and SD did not induce oxidative stress marker gene expression. SD but not DQ12 upregulated gene expressions of interleukin 1 Beta (IL1B), IL6, and IL8 as well as releases of IL-1β, IL-6, IL-8, and tumor necrosis factor α (TNFα). Exposing wild type, CASP1-/-, and NLRP3-/- co-cultures to SD induced IL1B gene expression in all co-cultures whereas IL-1β release was only induced in wild type co-cultures. In CASP1-/- and NLRP3-/- co-cultures, IL-6, IL-8, and TNFα releases were also reduced.

CONCLUSIONS

Since surfactants can decrease the toxicity of poorly soluble particles, the higher potency of SD than DQ12 in this surfactant-producing ALI model emphasizes the importance of readily soluble SD components such as microbial compounds. The higher potency of SD than DQ12 also renders SD a potential alternative particulate positive control for studies addressing acute inflammatory effects. The high pro-inflammatory potency depending on NLRP3, CASP-1, and IL-1β suggests that SD causes acute lung injury which may explain desert dust event-related increased respiratory morbidity and mortality.

Integration of metabolomics and network pharmacology to reveal the protective mechanism underlying Qibai Pingfei capsule on chronic obstructive pulmonary disease

In this study, we have employed metabolomics technology in combination with network pharmacology to ascertain the key metabolites and hub genes. The objective was to explore the pathway of Qibai Pingfei Capsule (QBPF) in treating COPD through metabolomics. We identified 96 differential metabolites in the lung tissues of rats belonging to control and model groups, out of which 47 were observed to be critical (VIP >2, p < 0.05). Furthermore, 16 important differential metabolites were reversed after QBPF treatment. Using network pharmacology, we identified 176 core targets of 81 drug-active ingredients. Our comprehensive analysis of network pharmacology and metabolomics enabled us to identify a core target, prostaglandin-endoperoxide synthase 2 (PTGS2), and a core metabolic pathway for glutathione metabolism. Finally, the result of molecular docking showed that PTGS2 had strong binding activity to 18 compounds including Fumarine and Kaempferol, etc.. PTGS2 is a marker of ferroptosis, so we wanted to explore whether QBPF could inhibit ferroptosis in COPD. The results showed that ferroptosis was involved in the pathogenesis of COPD, and QBPF could inhibit the occurrence of ferroptosis. In conclusion, the mechanism of QBPF for treating COPD may be related to PTGS2 expression, glutathione metabolism and ferroptosis.

MEGF6 prevents sepsis-induced acute lung injury in mice

OBJECTIVE

Acute lung injury (ALI) is featured as excessive inflammatory response and oxidative damage, and results in high death rate of septic patients. This research intends to determine the function of multiple EGF like domains 6 (MEGF6) in sepsis-induced ALI.

METHODS

Mice were intratracheally treated with adenovirus to knock down or overexpress MEGF6 in lung tissues, and then were subjected to cecum ligation and puncture (CLP) operation to induce ALI. Primary peritoneal macrophages were isolated, and were knocked down or overexpressed with MEGF6, and then, were stimulated with lipopolysaccharide (LPS) to confirm its role in vitro.

RESULTS

Serum and lung MEGF6 levels were significantly elevated in septic mice. MEGF6 knockdown exacerbated, while MEGF6 overexpression prevented inflammation, oxidative damage and ALI in CLP mice. Meanwhile, LPS-elicited inflammatory response and oxidative damage in primary macrophages were reduced by MEGF6 overexpression, but were further aggravated by MEGF6 knockdown. Mechanistic studies revealed that MEGF6 reduced cluster of differentiation 38 (CD38) expression and subsequently elevated intracellular nicotinamide adenine dinucleotide levels, thereby activating sirtuin 1 (SIRT1) without affecting the protein expression. SIRT1 suppression or CD38 overexpression with either genetic or pharmacologic methods remarkably blunted the lung protective effects of MEGF6 in CLP mice.

CONCLUSION

MEGF6 prevents CLP-induced ALI through CD38/SIRT1 pathway, and it might be a valuable therapeutic candidate for the management of sepsis-induced ALI.

Genetic deletion or pharmacological inhibition of soluble epoxide hydrolase attenuated particulate matter 2.5 exposure mediated lung injury

Air pollution represented by particulate matter 2.5 (PM2.5) is closely related to diseases of the respiratory system. Although the understanding of its mechanism is limited, pulmonary inflammation is closely correlated with PM2.5-mediated lung injury. Soluble epoxide hydrolase (sEH) and epoxy fatty acids play a vital role in the inflammation. Herein, we attempted to use the metabolomics of oxidized lipids for analyzing the relationship of oxylipins with lung injury in a PM2.5-mediated mouse model, and found that the cytochrome P450 oxidases/sEH mediated metabolic pathway was involved in lung injury. Furthermore, the sEH overexpression was revealed in lung injury mice. Interestingly, sEH genetic deletion or the selective sEH inhibitor TPPU increased levels of epoxyeicosatrienoic acids (EETs) in lung injury mice, and inactivated pulmonary macrophages based on the MAPK/NF-κB pathway, resulting in protection against PM2.5-mediated lung injury. Additionally, a natural sEH inhibitor luteolin from Inula japonica displayed a pulmonary protective effect towards lung injury mediated by PM2.5 as well. Our results are consistent with the sEH message and protein being both a marker and mechanism for PM2.5-induced inflammation, which suggest its potential as a pharmaceutical target for treating diseases of the respiratory system.