Pravastatin attenuates sepsis-induced acute lung injury through decreasing pulmonary microvascular permeability via inhibition of Cav-1/eNOS pathway

Enhanced itaconic acid secretion from macrophages mediates the protection of mesenchymal stem cell-derived exosomes on lipopolysaccharide-induced acute lung injury mice

BACKGROUND

Alveolar macrophages (AMs) is critical to exacerbate acute lung injury (ALI) induced by lipopolysaccharide (LPS) via inhibiting inflammation, which could by shifted by mesenchymal stem cell-derived exosomes (MSC-exos). But the underlying rationale is not fully clarified. Our study aimed to analyze the significance of itaconic acid (ITA) in mediating the protective effects of MSC-exos on LPS-induced ALI.

METHODS

MSC-exos were used to treat pulmonary microvascular endothelial cells (PMVECs) co-cultured with AMs under LPS stimulation. si-IRG1 was transfected to AMs. PMVEC permeability, apoptosis rates, and inflammatory cytokine levels were assessed. In vivo, C57BL/6 wild-type (WT) and Irg1-/- mice were employed to explore the protection of MSC-exos against LPS-induced ALI. The lung injury was determined by histological and biochemical assays. ITA levels were measured using gas chromatography-mass spectrometry. Western blot and flow cytometry analyses were performed to assess M1/M2 polarization.

RESULTS

Co-culture with AMs significantly increased PMVEC permeability, apoptosis rates, IL-6, TNF-α levels and Claudin-5 and ZO-1 expression induced by LPS treatment, which were attenuated by MSC-exos accompanied by enhanced ITA level. After si-IRG1 transfection, MSC-exos' protective efficacy was reversed, with suppressed M2 polarization. In vivo, MSC-exos alleviated alveolar structure disruption, pulmonary edema, inflammation and increased ITA concentration in WT mice but had reduced effects in Irg1-/- mice, with neglected M2 polarization.

CONCLUSIONS

ITA secretion facilitated the MSC-exos' protective benefits on LPS-induced PMVEC damage and ALI in mice by promoting AM M2 polarization, highlighting a potential therapeutic strategy for ALI and related inflammatory lung diseases.

Curcumin-mediated enhancement of lung barrier function in rats with high-altitude-associated acute lung injury via inhibition of inflammatory response

BACKGROUND

Exposure to a hypobaric hypoxic environment at high altitudes can lead to lung injury. In this study, we aimed to determine whether curcumin (Cur) could improve lung barrier function and protect against high-altitude-associated acute lung injury.

METHODS

Two hundred healthy rats were randomly divided into standard control, high-altitude control (HC), salidroside (40 mg/kg, positive control), and Cur (200 mg/kg) groups. Each group was further divided into five subgroups. Basic vital signs, lung injury histopathology, routine blood parameters, plasma lactate level, and arterial blood gas indicators were evaluated. Protein and inflammatory factor (tumor necrosis factor α (TNF-α), interleukin [IL]-1β, IL-6, and IL-10) concentrations in bronchoalveolar lavage fluid (BALF) were determined using the bicinchoninic acid method and enzyme-linked immunosorbent assay, respectively. Inflammation-related and lung barrier function-related proteins were analyzed using immunoblotting.

RESULTS

Cur improved blood routine indicators such as hemoglobin and hematocrit and reduced the BALF protein content and TNF-α, IL-1β, and IL-6 levels compared with those in the HC group. It increased IL-10 levels and reduced pulmonary capillary congestion, alveolar hemorrhage, and the degree of pulmonary interstitial edema. It increased oxygen partial pressure, oxygen saturation, carbonic acid hydrogen radical, and base excess levels, and the expression of zonula occludens 1, occludin, claudin-4, and reduced carbon dioxide partial pressure, plasma lactic acid, and the expression of phospho-nuclear factor kappa.

CONCLUSIONS

Exposure to a high-altitude environment for 48 h resulted in severe lung injury in rats. Cur improved lung barrier function and alleviated acute lung injury in rats at high altitudes.

The critical roles of caveolin-1 in lung diseases

Caveolin-1 (Cav-1), a structural and functional component in the caveolae, plays a critical role in transcytosis, endocytosis, and signal transduction. Cav-1 has been implicated in the mediation of cellular processes by interacting with a variety of signaling molecules. Cav-1 is widely expressed in the endothelial cells, smooth muscle cells, and fibroblasts in the various organs, including the lungs. The Cav-1-mediated internalization and regulation of signaling molecules participate in the physiological and pathological processes. Particularly, the MAPK, NF-κB, TGFβ/Smad, and eNOS/NO signaling pathways have been involved in the regulatory effects of Cav-1 in lung diseases. The important effects of Cav-1 on the lungs indicate that Cav-1 can be a potential target for the treatment of lung diseases. A Cav-1 scaffolding domain peptide CSP7 targeting Cav-1 has been developed. In this article, we mainly discuss the structure of Cav-1 and its critical roles in lung diseases, such as pneumonia, acute lung injury (ALI), asthma, chronic obstructive pulmonary disease (COPD), pulmonary hypertension, pulmonary fibrosis, and lung cancer.

The effects of iron deficient and high iron diets on SARS-CoV-2 lung infection and disease

Introduction

The severity of Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is often dictated by a range of comorbidities. A considerable literature suggests iron deficiency and iron overload may contribute to increased infection, inflammation and disease severity, although direct causal relationships have been difficult to establish.

Methods

Here we generate iron deficient and iron loaded C57BL/6 J mice by feeding standard low and high iron diets, with mice on a normal iron diet representing controls. All mice were infected with a primary SARS-CoV-2 omicron XBB isolate and lung inflammatory responses were analyzed by histology, immunohistochemistry and RNA-Seq.

Results

Compared with controls, iron deficient mice showed no significant changes in lung viral loads or histopathology, whereas, iron loaded mice showed slightly, but significantly, reduced lung viral loads and histopathology. Transcriptional changes were modest, but illustrated widespread dysregulation of inflammation signatures for both iron deficient vs. controls, and iron loaded vs. controls. Some of these changes could be associated with detrimental outcomes, whereas others would be viewed as beneficial.

Discussion

Diet-associated iron deficiency or overload thus induced modest modulations of inflammatory signatures, but no significant histopathologically detectable disease exacerbations.

Polygala tenuifolia willd. Extract alleviates LPS-induced acute lung injury in rats via TLR4/NF-κB pathway and NLRP3 inflammasome suppression

BACKGROUND

Acute lung injury (ALI) has received considerable attention in the field of critical care as it can lead to high mortality rates. Polygala tenuifolia, a traditional Chinese medicine with strong expectorant properties, can be used to treat pneumonia. Owing to the complexity of its composition, the main active ingredient is not yet known. Thus, there is a need to identify its constituent compounds and mechanism of action in the treatment of ALI using advanced technological means.

PURPOSE

We investigated the anti-inflammatory mechanism and constituent compounds with regard to the effect of P. tenuifolia Willd. extract (EPT) in lipopolysaccharide (LPS)-induced ALI in vivo and in vitro.

METHODS

The UHPLC-Q-Exactive Orbitrap MS technology was used to investigate the chemical profile of EPT. Network pharmacology was used to predict the targets and pathways of action of EPT in ALI, and molecular docking was used to validate the binding of polygalacic acid to Toll-like receptor (TLR) 4. The main compounds were determined using LC-MS. A rat model of LPS-induced ALI was established, and THP-1 cells were stimulated with LPS and adenosine triphosphate (ATP) to construct an in vitro model. Pathological changes were observed using hematoxylin and eosin staining, Wright-Giemsa staining, and immunohistochemistry. The expression of inflammatory factors (NE, MPO, Ly-6 G, TNF-α, IL-1β, IL-6, and iNOS) was determined using enzyme-linked immunosorbent assay, real-time fluorescence quantitative polymerase chain reaction, and western blotting. The LPS + ATP-induced inflammation model in THP-1 cells was used to verify the in vivo experimental results.

RESULTS

Ninety-nine compounds were identified or tentatively deduced from EPT. Using network pharmacology, we found that TLR4/NF-κB may be a relevant pathway for the prevention and treatment of ALI by EPT. Polygalacic acid in EPT may be a potential active ingredient. EPT could alleviate LPS-induced histopathological lung damage and reduce the wet/dry lung weight ratio in the rat model of ALI. Moreover, EPT decreased the white blood cell and neutrophil counts in the bronchoalveolar lavage fluid and decreased the expression of genes and proteins of relevant inflammatory factors (NE, MPO, Ly-6 G, TNF-α, IL-1β, IL-6, and iNOS) in lung tissues. It also increased the expression of endothelial-type nitric oxide synthase expression. Western blotting confirmed that EPT may affect TLR4/NF-κB and NLRP3 signaling pathways in vivo. Similar results were obtained in THP-1 cells.

CONCLUSION

EPT reduced the release of inflammatory factors by affecting TLR4/NF-κB and NLRP3 signaling pathways, thereby attenuating the inflammatory response of ALI. Polygalacic acid is the likely compounds responsible for these effects.

Endothelial dysfunction: Pathophysiology and therapeutic targets for sepsis-induced multiple organ dysfunction syndrome

Sepsis and septic shock are critical medical conditions characterized by a systemic inflammatory response to infection, significantly contributing to global mortality rates. The progression to multiple organ dysfunction syndrome (MODS) represents the most severe complication of sepsis and markedly increases clinical mortality. Central to the pathophysiology of sepsis, endothelial cells play a crucial role in regulating microcirculation and maintaining barrier integrity across various organs and tissues. Recent studies have underscored the pivotal role of endothelial function in the development of sepsis-induced MODS. This review aims to provide a comprehensive overview of the pathophysiology of sepsis-induced MODS, with a specific focus on endothelial dysfunction. It also compiles compelling evidence regarding potential small molecules that could attenuate sepsis and subsequent multi-organ damage by modulating endothelial function. Thus, this review serves as an essential resource for clinical practitioners involved in the diagnosing, managing, and providing intensive care for sepsis and associated multi-organ injuries, emphasizing the importance of targeting endothelial cells to enhance outcomes of the patients.

Protective Effect of Hibifolin on Lipopolysaccharide-Induced Acute Lung Injury Through Akt Phosphorylation and NFκB Pathway

Acute lung injury (ALI) is a difficult condition to manage, especially when it is complicated by bacterial sepsis. Hibifolin, a flavonoid glycoside, has anti-inflammatory properties that make it a potential treatment for ALI. However, more research is needed to determine its effectiveness in LPS-induced ALI. In this study, male ICR mice were treated with hibifolin before LPS-induced ALI. Protein content and neutrophil count in bronchoalveolar lavage (BAL) fluid were measured by BCA assay and Giemsa staining method, respectively. The levels of proinflammatory cytokines and adhesive molecules were detected by ELISA assay. The expression of NFκB p65 phosphorylation, IκB degradation, and Akt phosphorylation was assessed by western blot assay. Hibifolin pre-treatment significantly reduced pulmonary vascular barrier dysfunction and neutrophil infiltration into the BAL fluid in LPS-induced ALI mice. In addition, LPS-induced expression of proinflammatory cytokines (IL-1β, IL-6, TNF-α) and adhesive molecules (ICAM-1, VCAM-1) within the BAL fluid were markedly reduced by hibifolin in LPS-induced ALI mice. More, hibifolin inhibited LPS-induced phosphorylation of NFκB p65, degradation of IκB, and phosphorylation of Akt in lungs with ALI mice. In conclusion, hibifolin shows promise in improving the pathophysiological features and proinflammatory responses of LPS-induced ALI in mice through the NFκB pathway and its upstream factor, Akt phosphorylation.

Dexmedetomidine mitigates lipopolysaccharide-induced acute lung injury by modulating heat shock protein A12B to inhibit the toll-like receptor 4/nuclear factor-kappa B signaling pathway

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS): Life-threatening medical conditions characterized by high morbidity and mortality rates, where the inflammatory process plays a crucial role in lung tissue damage, especially in models induced by lipopolysaccharide (LPS). Heat shock protein A12B (HSPA12B) has strong anti-infammatory properties However, it is unknown whether increased HSPA12B is protective against LPS-induced ALI. And Dexmedetomidine (DEX) is a potent α2-adrenergic receptor (α2-AR) agonist that has been shown to protect against sepsis-induced lung injury, however, the underlying mechanisms of this protection are not fully understood. This study utilized bioinformatics analysis and an LPS-induced ALI model to explore how DEX alleviates lung injury by modulating HSPA12B and inhibiting the Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway. Results indicate that HSPA12B overexpression and DEX pre-treatment markedly mitigated LPS-induced lung injury, which was evaluated by the deterioration of histopathology, histologic scores, the W/D weight ratio, and total protein expression, tumor necrosis factor-alpha (TNF-α), and interleukin-1β (IL-1β) in the BALF, and the levels of NO, MDA,SOD and MPO in the lung. Moreover, HSPA12B overexpression and DEX pre-treatment significantly reduces lung injury and inflammation levels by upregulating HSPA12B and inhibiting the activation of the TLR4/NF-κB signaling pathway. On the contrary, when the expression of HSPA12B is inhibited, the protective effect of DEX pre-treatment on lung tissue is significantly weakened.In summary, our research demonstrated that the increased expression of AAV-mediated HSPA12B in the lungs of mice inhibits acute inflammation and suppresses the activation of TLR4/NF-κB pathway in a murine model of LPS-induced ALI. DEX could enhance HSPA12B and inhibit the initiation and development of inflammation through down-regulating TLR4/NF-κB pathway.These findings highlight the potential of DEX as a therapeutic agent for treating ALI and ARDS, offering new strategies for clinical intervention.

GDF11 OVEREXPRESSION ALLEVIATES SEPSIS-INDUCED LUNG MICROVASCULAR ENDOTHELIAL BARRIER DAMAGE BY ACTIVATING SIRT1/NOX4 SIGNALING TO INHIBIT FERROPTOSIS

ABSTRACT

Sepsis is a lethal clinical syndrome, and acute lung injury (ALI) is the earliest and most serious complication. We aimed to explore the role of growth differentiation factor 11 (GDF11) in sepsis-induced dysfunction of lung microvascular endothelial barrier in vivo and in vitro to elucidate its potential mechanism related to sirtuin 1 (SIRT1)/NADPH oxidase 4 (NOX4) signaling. Cecal ligation and puncture (CLP)-induced sepsis mice and lipopolysaccharide (LPS)-induced pulmonary microvascular endothelial cells (PMECs) were used in this study. Histopathological changes in lung tissues were tested by hematoxylin-eosin staining. Lung wet-to-dry weight ratio and inflammatory factors contents in bronchoalveolar lavage fluid were assessed. Evens blue index, trans-epithelial electrical resistance, and expression of zona occludens 1 (ZO-1), occludin-1, and claudin-1 were used to evaluate alveolar barrier integrity. Reactive oxygen species, lipid peroxidation, and ferroptosis markers were analyzed. Iron deposition in the lung tissues was assessed using Prussian blue staining. Intracellular Fe 2+ level was detected using FerroOrange staining. Additionally, expression of GDF11, SIRT1, and NOX4 was estimated with western blot. Then, EX527, a SIRT1 inhibitor, was employed to treat GDF11-overexpressed PMECs with LPS stimulation to clarify the regulatory mechanism. Results showed that GDF11 overexpression attenuated sepsis-induced pathological changes and inflammation and maintained alveolar barrier integrity. Moreover, GDF11 overexpression inhibited ferroptosis, upregulated SIRT1 expression and downregulated NOX4 expression. Additionally, EX527 treatment relieved the impacts of GDF11 overexpression on ferroptosis and destruction of integrity of human pulmonary microvascular endothelial cells exposed to LPS. Taken together, GDF11 overexpression could alleviate sepsis-induced lung microvascular endothelial barrier damage by activating SIRT1/NOX4 signaling to inhibit ferroptosis. Our findings potentially provide new molecular target for clinical therapy of ALI.

Oxymatrine attenuates sepsis-induced inflammation and organ injury via inhibition of HMGB1/RAGE/NF-κB signaling pathway

Sepsis is a life-threatening organ dysfunction that endangers patient lives and is caused by an imbalance in the host defense against infection. Sepsis continues to be a significant cause of morbidity and mortality in critically sick patients. Oxymatrine (OMT), a quinolizidine alkaloid derived from the traditional Chinese herb Sophora flavescens Aiton, has been shown to have anti-inflammatory effects on a number of inflammatory illnesses according to research. In this study, we aimed to evaluate the therapeutic effects of OMT on sepsis and explore the underlying mechanisms. We differentiated THP-1 cells into THP-1 macrophages and studied the anti-inflammatory mechanism of OMT in a lipopolysaccharide (LPS)-induced THP-1 macrophage sepsis model. Activation of the receptor for advanced glycation end products (RAGE), as well as NF-κB, was assessed by Western blot analysis and immunofluorescence staining. ELISA was used to measure the levels of inflammatory factors. We found that OMT significantly inhibited HMGB1-mediated RAGE/NF-κB activation and downstream inflammatory cytokine production in response to LPS stimulation. Finally, an in vivo experiment was performed on septic mice to further study the effect of OMT on injured organs. The animal experiments showed that OMT significantly inhibited HMGB1-mediated RAGE/NF-κB activation, protected against the inflammatory response and organ injury induced by CLP, and prolonged the survival rate of septic mice. Herein, we provide evidence that OMT exerts a significant therapeutic effect on sepsis by inhibiting the HMGB1/RAGE/NF-κB signaling pathway.

Endothelial cell dynamics in sepsis-induced acute lung injury and acute respiratory distress syndrome: pathogenesis and therapeutic implications

Sepsis, a prevalent critical condition in clinics, continues to be the leading cause of death from infections and a global healthcare issue. Among the organs susceptible to the harmful effects of sepsis, the lungs are notably the most frequently affected. Consequently, patients with sepsis are predisposed to developing acute lung injury (ALI), and in severe cases, acute respiratory distress syndrome (ARDS). Nevertheless, the precise mechanisms associated with the onset of ALI/ARDS remain elusive. In recent years, there has been a growing emphasis on the role of endothelial cells (ECs), a cell type integral to lung barrier function, and their interactions with various stromal cells in sepsis-induced ALI/ARDS. In this comprehensive review, we summarize the involvement of endothelial cells and their intricate interplay with immune cells and stromal cells, including pulmonary epithelial cells and fibroblasts, in the pathogenesis of sepsis-induced ALI/ARDS, with particular emphasis placed on discussing the several pivotal pathways implicated in this process. Furthermore, we discuss the potential therapeutic interventions for modulating the functions of endothelial cells, their interactions with immune cells and stromal cells, and relevant pathways associated with ALI/ARDS to present a potential therapeutic strategy for managing sepsis and sepsis-induced ALI/ARDS.

The role of FPR2-mediated ferroptosis in formyl peptide-induced acute lung injury against endothelial barrier damage and protective effect of the mitochondria-derived peptide MOTS-c

BACKGROUND

Acute lung injury (ALI) has garnered significant attention in the field of respiratory and critical care due to its high mortality and morbidity, and limited treatment options. The role of the endothelial barrier in the development of ALI is crucial. Several bacterial pathogenic factors, including the bacteria-derived formyl peptide (fMLP), have been implicated in damaging the endothelial barrier and initiating ALI. However, the mechanism by which fMLP causes ALI remains unclear. In this study, we aim to explore the mechanisms of ALI caused by fMLP and evaluate the protective effects of MOTS-c, a mitochondrial-derived peptide.

METHODS

We established a rat model of ALI and a human pulmonary microvascular endothelial cell (HPMVEC) model of ALI by treatment with fMLP. In vivo experiments involved lung histopathology assays, assessments of inflammatory and oxidative stress factors, and measurements of ferroptosis-related proteins and barrier proteins to evaluate the severity of fMLP-induced ALI and the type of tissue damage in rats. In vitro experiments included evaluations of fMLP-induced damage on HPMVEC using cell activity assays, assessments of inflammatory and oxidative stress factors, measurements of ferroptosis-related proteins, endothelial barrier function assays, and examination of the key role of FPR2 in fMLP-induced ALI. We also assessed the protective effect of MOTS-c and investigated its mechanism on the fMLP-induced ALI in vivo and in vitro.

RESULTS

Results from both in vitro and in vivo experiments demonstrate that fMLP promotes the expression of inflammatory and oxidative stress factors, activates ferroptosis and disrupts the vascular endothelial barrier, ultimately contributing to the development and progression of ALI. Mechanistically, ferroptosis mediated by FPR2 plays a key role in fMLP-induced injury, and the Nrf2 and MAPK pathways are involved in this process. Knockdown of FPR2 and inhibition of ferroptosis can attenuate ALI induced by fMLP. Moreover, MOTS-c could protect the vascular endothelial barrier function by inhibiting ferroptosis and suppressing the expression of inflammatory and oxidative stress factors through Nrf2 and MAPK pathways, thereby alleviating fMLP-induced ALI.

CONCLUSION

Overall, fMLP disrupts the vascular endothelial barrier through FPR2-mediated ferroptosis, leading to the development and progression of ALI. MOTS-c demonstrates potential as a protective treatment against ALI by alleviating the damage induced by fMLP.

Comprehensive review of potential drugs with anti-pulmonary fibrosis properties

Pulmonary fibrosis is a chronic and progressive lung disease characterized by the accumulation of scar tissue in the lungs, which leads to impaired lung function and reduced quality of life. The prognosis for idiopathic pulmonary fibrosis (IPF), which is the most common form of pulmonary fibrosis, is generally poor. The median survival for patients with IPF is estimated to be around 3-5 years from the time of diagnosis. Currently, there are two approved drugs (Pirfenidone and Nintedanib) for the treatment of IPF. However, Pirfenidone and Nintedanib are not able to reverse or cure pulmonary fibrosis. There is a need for new pharmacological interventions that can slow or halt disease progression and cure pulmonary fibrosis. This review aims to provide an updated overview of current and future drug interventions for idiopathic pulmonary fibrosis, and to summarize possible targets of potential anti-pulmonary fibrosis drugs, providing theoretical support for further clinical combination therapy or the development of new drugs.

Protective effect of zerumbone on sepsis-induced acute lung injury through anti-inflammatory and antioxidative activity via NF-κB pathway inhibition and HO-1 activation

Sepsis is a systemic illness for which there are no effective preventive or therapeutic therapies. Zerumbone, a natural molecule, has anti-oxidative and anti-inflammatory properties that may help to prevent sepsis. In the present study, we have assessed the protective effect of zerumbone against sepsis-induced acute lung injury (ALI) and its underlying mechanisms. During the experiment, mice were divided into five groups: a sham group, a sepsis-induced ALI group, and three sepsis groups that are pre-treated with zerumbone at different concentrations. We found that zerumbone greatly decreased the sepsis-induced ALI using histological investigations. Also, zerumbone treatment reduced the sepsis-induced inflammatory cytokine concentrations as well as the number of infiltrating inflammatory cells in BALF compared to non-treated sepsis animals. The zerumbone-pretreated sepsis groups had reduced pulmonary myeloperoxidase (MPO) activity than the sepsis groups. Moreover, the mechanism underlying the protective action of zerumbone on sepsis is accomplished by the activation of antioxidant genes such as nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), superoxide dismutase (SOD), and heme oxygenase 1 (HO-1). The obtained results revealed that zerumbone inhibited the sepsis-induced ALI through its anti-inflammatory and antioxidative activity via inhibition of the NF-κB pathway and activation of HO-1 pathway. Our findings demonstrate that zerumbone pretreatment suppresses sepsis-induced ALI via antioxidative activities and anti-inflammatory, implying that zerumbone could be a viable preventive agent for sepsis-induced ALI.

Isoegomaketone alleviates inflammatory response and oxidative stress in sepsis lung injury

BACKGROUND

Sepsis is a life-threatening condition characterized by acute organ dysfunction, which frequently leads to acute lung injury (ALI) in approximately 40% of cases. Isoegomaketone (IK) is a constituent of essential oil found in P. frutescens, known for its diverse biological properties, including anti-inflammatory and antitumor effects. However, the regulatory impact of IK on ALI in the context of sepsis remains poorly understood.

METHODS

Pathological alterations in lung tissues were assessed using hematoxylin and eosin staining. Enumeration of total leukocytes and neutrophils in bronchoalveolar lavage fluid (BALF) was performed using a hematocytometer, while the levels of interleukin (IL)-6, IL-1β, IL-10, and IL-17 in BALF were quantified using enzyme-linked immunosorbent serological assay. In addition, the levels of malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD), and glutathione (GSH) in lung tissues were assessed using respective commercial kits; cell apoptosis was evaluated using the terminal deoxynucleotide transferase--mediated dUTP nick end-labeling assay, and protein expressions were determined through Western blot analysis.

RESULTS

Our findings revealed that cecal ligation and puncture (CLP) treatment in mice induced severe lung injury, characterized by increased lung injury scores, significant bleeding, neutrophil infiltration, and alveolar edema. However, treatment with IK at a dose of 10 mg/kg ameliorated CLP-induced lung injury, while IK dose of 5 mg/kg showed no significant effect. Additionally, IK treatment at 10 mg/kg reduced CLP-induced inflammation by decreasing levels of IL-6, IL-1β, IL-10, and IL-17. Furthermore, IK at 10 mg/kg attenuated CLP-induced oxidative stress by modulating levels of MDA, MPO, SOD, and GSH. Moreover, IK treatment with a dose of 10 mg/kg activated the nuclear factor erythroid 2-related factor 2-heme oxygenase-1 (Nrf2-HO-1) pathway by enhancing the protein expressions of Nrf2 and HO-1.

CONCLUSION

This study demonstrates that IK could mitigate the inflammatory response and oxidative stress associated with sepsis-induced ALI, supporting IK as a promising therapeutic agent for the treatment of sepsis-associated ALI.

Knockdown of angiopoietin-like 4 suppresses sepsis-induced acute lung injury by blocking the NF-κB pathway activation and hindering macrophage M1 polarization and pyroptosis

OBJECTIVE

Sepsis-induced acute lung injury (ALI) is a life-threatening disease. Macrophage pyroptosis has been reported to exert function in ALI. We aimed to investigate the mechanisms of ANGPTL4-mediated cell pyroptosis in sepsis-induced ALI, thus providing new insights into the pathogenesis and prevention and treatment measures of sepsis-induced ALI.

METHODS

In vivo animal models and in vitro cell models were established by cecal ligation and puncture (CLP) method and lipopolysaccharide-induced macrophages RAW264.7. ANGPTL4 was silenced in CLP mice or macrophages, followed by the determination of ANGPTL4 expression in bronchoalveolar lavage fluid (BALF) or macrophages. Lung histopathology was observed by H&E staining, with pathological injury scores evaluated and lung wet and dry weight ratio recorded. M1/M2 macrophage marker levels (iNOS/CD86/Arg1), inflammatory factor (TNF-α/IL-6/IL-1β/iNOS) expression in BALF, cell death and pyroptosis, NLRP3 inflammasome, cell pyroptosis-related protein (NLRP3/Cleaved-caspase-1/caspase-1/GSDMD-N) levels, NF-κB pathway activation were assessed by RT-qPCR/ELISA/flow cytometry/Western blot, respectively.

RESULTS

ANGPTL4 was highly expressed in mice with sepsis-induced ALI, and ANGPTL4 silencing ameliorated sepsis-induced ALI in mice. In vivo, ANGPTL4 silencing repressed M1 macrophage polarization and macrophage pyroptosis in mice with sepsis-induced ALI. In vitro, ANGPTL4 knockout impeded LPS-induced activation and pyroptosis of M1 macrophages and hindered LPS-induced activation of the NF-κB pathway in macrophages.

CONCLUSION

Knockdown of ANGPTL4 blocks the NF-κB pathway activation, hinders macrophage M1 polarization and pyroptosis, thereby suppressing sepsis-induced ALI.

Simvastatin restores pulmonary endothelial function in the setting of pulmonary over-circulation

Statin therapy is a cornerstone in the treatment of systemic vascular diseases. However, statins have failed to translate as therapeutics for pulmonary vascular disease. Early pulmonary vascular disease in the setting of congenital heart disease (CHD) is characterized by endothelial dysfunction, which precedes the more advanced stages of vascular remodeling. These features make CHD an ideal cohort in which to re-evaluate the potential pulmonary vascular benefits of statins, with a focus on endothelial biology. However, it is critical that the full gamut of the pleiotropic effects of statins in the endothelium are uncovered. The purpose of this investigation was to evaluate the therapeutic potential of simvastatin for children with CHD and pulmonary over-circulation, and examine mechanisms of simvastatin action on the endothelium. Our data demonstrate that daily simvastatin treatment preserves endothelial function in our shunt lamb model of pulmonary over-circulation. Further, using pulmonary arterial endothelial cells (PAECs) isolated from Shunt and control lambs, we identified a new mechanism of statin action mediated by increased expression of the endogenous Akt1 inhibitor, C-terminal modifying protein (CTMP). Increases in CTMP were able to decrease the Akt1-mediated mitochondrial redistribution of endothelial nitric oxide synthase (eNOS) which correlated with increased enzymatic coupling, identified by increases in NO generation and decreases in NOS-derived superoxide. Together our data identify a new mechanism by which simvastatin enhances NO signaling in the pulmonary endothelium and identify CTMP as a potential therapeutic target to prevent the endothelial dysfunction that occurs in children born with CHD resulting in pulmonary over-circulation.

Gemfibrozil Improves Microcirculatory Oxygenation of Colon and Liver without Affecting Mitochondrial Function in a Model of Abdominal Sepsis in Rats

Recent studies observed, despite an anti-hyperlipidaemic effect, a positive impact of fibrates on septic conditions. This study evaluates the effects of gemfibrozil on microcirculatory variables, mitochondrial function, and lipid peroxidation levels with regard to its potential role as an indicator for oxidative stress in the colon and liver under control and septic conditions and dependencies on PPARα-mediated mechanisms of action. With the approval of the local ethics committee, 120 Wistar rats were randomly divided into 12 groups. Sham and septic animals were treated with a vehicle, gemfibrozil (30 and 100 mg/kg BW), GW 6471 (1 mg/kg BW, PPARα inhibitor), or a combination of both drugs. Sepsis was induced via the colon ascendens stent peritonitis (CASP) model. Then, 24 h post sham or CASP surgery, a re-laparotomy was performed. Measures of vital parameters (heart rate (HR), mean arterial pressure (MAP), and microcirculation (µHbO2)) were recorded for 90 min. Mitochondrial respirometry and assessment of lipid peroxidation via a malondialdehyde (MDA) assay were performed on colon and liver tissues. In the untreated sham animals, microcirculation remained stable, while pre-treatment with gemfibrozil showed significant decreases in the microcirculatory oxygenation of the colon. In the CASP animals, µHbO2 levels in the colon and the liver were significantly decreased 90 min after laparotomy. Pre-treatment with gemfibrozil prevented the microcirculatory aberrations in both organs. Gemfibrozil did not affect mitochondrial function and lipid peroxidation levels in the sham or CASP animals. Gemfibrozil treatment influences microcirculation depending on the underlying condition. Gemfibrozil prevents sepsis-induced microcirculatory aberrances in the colon and liver PPARα-independently. In non-septic animals, gemfibrozil impairs the microcirculatory variables in the colon without affecting those in the liver.

TRPC6 Deletion Enhances eNOS Expression and Reduces LPS-Induced Acute Lung Injury

Acute lung injury (ALI) is characterized by endothelial barrier disruption and associated inflammatory responses, and transient receptor potential cation channel 6 (TRPC6)-mediated Ca2+ influx is critical for endothelial hyperpermeability. In this study, we investigated the role of TRPC6 in LPS-induced ALI, analyzed gene expression in WT and TRPC6-/- lungs using RNA sequencing, and explored the effects of TRPC6 in the LPS-induced hyperpermeability in human umbilical vein endothelial cells (HUVECs) to elucidate the underlying mechanisms. Intratracheal instillation of LPS caused edema in the mouse lungs. Deletion of TRPC6 reduced LPS-induced lung edema and decreased cell infiltration. RNA sequencing analysis suggested that downregulated cell adhesion molecules in TRPC6-/- lungs may be responsible for their resistance to LPS-induced injury. In addition, downregulation of TRPC6 significantly alleviated the LPS-induced decrease in eNOS expression in lung tissue as well as in HUVECs. Moreover, inhibition of TRPC6 with the channel antagonist larixyl led to a decrease in LPS-induced hyperpermeability and ROS production in HUVECs, which could be reversed by blocking eNOS. Our findings suggest that inhibition of TRPC6 ameliorates LPS-induced ALI, which may be achieved by acting on the cell adhesion molecule signaling pathway and participating in the regulation of eNOS levels in endothelial cells.

TMT-based quantitative proteomics reveals the targets of andrographolide on LPS-induced liver injury

BACKGROUND

Andrographolide (Andro) is a diterpenoid derived from Andrographis paniculate, which has anti-inflammatory, antibacterial, antiviral and hepatoprotective activities. Gram-negative bacterial infections can cause varying degrees of liver injury in chickens, although Andro has been shown to have a protective effect on the liver, its underlying mechanism of action and effects on liver proteins are not known.

METHODS

The toxicity of Andro on the viability of leghorn male hepatoma (LMH) cells at different concentrations and times was analyzed by CCK-8 assays. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the culture supernatants were measured using an automatic biochemical analyzer to evaluate the protective effect of androscopolide on LPS-induced injury of LMH cells. Subsequently, TMT proteomics analysis were performed on the negative control group (NC group), LPS, and LPS-Andro groups, and bioinformatics analysis was performed on the differentially expressed proteins (DEPs).

RESULTS

It was found that Andro reduced ALT and AST levels in the cell supernatant and alleviated LPS-induced injury in LMH cells. Proteomic analysis identified 50 and 166 differentially expressed proteins in the LPS vs. NC group and LPS-Andro vs. LPS group, respectively. Andro may be involved in steroid metabolic processes, negative regulation of MAPK cascade, oxidative stress, and other processes to protect against LPS-induced liver injury.

CONCLUSIONS

Andro protects against LPS-induced liver injury, HMGCS1, HMGCR, FDPS, PBK, CAV1, PRDX1, PRDX4, and PRDX6, which were identified by differential proteomics, may be the targets of Andro. Our study may provide new theoretical support for Andro protection against liver injury.

Histone methyltransferase SETD2 inhibits M1 macrophage polarization and glycolysis by suppressing HIF-1α in sepsis-induced acute lung injury

Sepsis is a severe syndrome caused by the imbalance of the host response to infection, accompanied by multiple organ damage, especially acute lung injury. SET Domain-Containing 2 (SETD2) is a methyltransferase catalyzing H3 lysine 36 trimethylation (H3K36me3) that regulates multiple biological processes. This study focused on explicating the action of SETD2 on macrophage function in sepsis and the precise mechanism involved. Enzyme-linked immunosorbent assay, real-time quantitative polymerase chain reaction (RT-qPCR), and Western blotting were used to determine expression. Luciferase reporter assay and chromatin immunoprecipitation assay were conducted to detect the binding of SETD2 or H3K36me3 with the hypoxia-inducible factor 1, alpha subunit (Hif1a) gene. A sepsis-induced acute lung injury model was constructed via cecal ligation and puncture (CLP). SETD2 was decreased in RAW 264.7 cells stimulated by lipopolysaccharide (LPS). Besides, SETD2 suppressed M1 macrophage polarization and glycolysis caused by LPS. HIF-1α was enhanced in RAW 264.7 cells stimulated by LPS and inversely related to SETD2 expression. In addition, SETD2-catalyzed H3K36me3 bound to the Hif1a gene to modulate HIF-1α expression. Furthermore, Hif1a silencing suppressed Setd2 silencing-induced M1 macrophage polarization and glycolysis in RAW 264.7 cells. Moreover, overexpression of Setd2 inhibited CLP-induced lung injury and M1 macrophage polarization in mice. SETD2 suppressed M1 macrophage polarization and glycolysis via regulating HIF-1α through catalyzing H3K36me3 in sepsis.

Effect of angiotensin II on irradiation exacerbated decompression sickness

In some complicated situations, decompression sickness (DCS) combined with other injuries, such as irradiation, will seriously endanger life safety. However, it is still unclear whether irradiation will increase the incidence of DCS. This study was designed to investigate the damage effects of irradiation on decompression injury and the underlying mechanism. Sprague-Dawley rats were exposed to irradiation followed by hyperbaric decompressing and the mortality and decompression symptoms were observed. Lung tissue and bronchoalveolar lavage fluid were collected to detect the lung lesion, inflammation response, activity of the angiotensin system, oxidative stress, and relative signal pathway by multiple methods, including Q-PCR, western blot, and ELISA. As a result, pre-exposure to radiation significantly exacerbated disease outcomes and lung lesions of DCS. Mechanically, the up-regulation of angiotensin-converting enzyme expression and angiotensin II levels was responsible for the exacerbated DCS and lung lesions caused by predisposing irradiation exposure. Oxidative stress and PI3K/AKT signal pathway activation in pulmonary tissue were enhanced after irradiation plus decompression treatment. In conclusion, our results suggested that irradiation could exacerbate lung injury and the outcomes of DCS by activating the angiotensin system, which included eliciting oxidative stress and activation of the PI3K/AKT signal pathway.

Reduning alleviates sepsis-induced acute lung injury by reducing apoptosis of pulmonary microvascular endothelial cells

Introduction

Sepsis-induced acute lung injury (SALI) is a critical illness with high mortality, and pulmonary microvascular endothelial cells (PMECs) barrier dysfunction is a well-documented pathogenesis of SALI. The current study aimed to investigate the underlying mechanism of Reduning (RDN) in the treatment of SALI.

Methods

Network pharmacology and molecular dynamics simulation (MDS) were used to confirm the possibility of key active components of RDN combining with AKT1. Hematoxylin-eosin staining (HE) and immunohistochemistry (IHC) were used to investigate the effect of RDN in vivo. Immunofluorescence (IF) and co-immunoprecipitation (CoIP) were used to investigate the relationship between mammalian target of rapamycin (mTOR) and Bax in PMECs. ELISA was used to test the level of TNF-α. Flow cytometry was used to detect apoptosis. JC-1 and electron microscopy were used to evaluate mitochondrial damage. The results showed that RDN likely alleviated SALI via targeting AKT1.

Results

In vivo, RDN could evidently decrease the expression levels of apoptosis-related proteins, alleviate mitochondrial damage, reduce lung tissue edema, down-regulate the level of TNF-α in the serum, and improve the mortality of sepsis in mice. In vitro, RDN had a significant effect on reducing the level of apoptosis-related proteins and cell apoptosis rate, while also mitigated mitochondrial damage. Furthermore, RDN could effectively lower the level of Bax in PMECs and increase the level of mTOR both in vivo and in vitro. Notably, mTOR has the ability to directly bind to Bax, and RDN can enhance this binding capability.

Discussion

RDN could attenuate SALI through reducing apoptosis of PMECs, which is a promising therapeutic strategy for SALI prevention.

ELAVL1 promotes LPS-induced endothelial cells injury through modulation of cytokine storm

Sepsis is a life-threatening systemic organ dysfunction caused by the host's unregulated response to a widespread bacterial infection. Endothelial injury is a major pathophysiologic symptom of sepsis and is considered a critical factor in promoting the progression of disease severity. ELAV like RNA binding protein 1(ELAVL1) is a ubiquitously expressed RNA-binding protein that may play an important role during sepsis. Nonetheless, the molecular mechanisms of ELAVL1 on endothelial cell damage in sepsis have not been well defined. Here, we aimed to confirm the role of ELAVL1 in sepsis-induced endothelial cell damage using lipopolysaccharide (LPS)-induced zebrafish and endothelial cells (ECs) models. We found that zebrafish larvae treated with LPS exhibited systemic endothelial cell damage, mostly manifested as pericardial edema, curved tail, and impaired angiogenesis. LPS treatments also significantly induced the expression levels of inflammatory cytokines (interleukin-6 (IL-6), IL-8, and tumor necrosis factor (TNF)-α) in vivo. In vitro, we observed the increase of ELAVL1 cytoplasmic translocation with LPS treatment. Mechanistically, targeted disruption of the ELAVL1 gene decreased the expression of TNF-α, IL-6, and IL-8 during induction of sepsis and alleviated LPS-induced blood vessel injury in zebrafish. Taken together, our study indicates that ELAVL1 knockdown may alleviate sepsis-induced endothelial cells injury by suppressing cytokine storm. Our research suggests that inhibition of ELAVL1 could reduce the level of inflammatory cytokine production induced by LPS and protect against endothelial cell injury. ELAVL1 might be a potential therapeutic target to block endothelial cells injury associated with sepsis.

Yue-bi-tang attenuates adriamycin-induced nephropathy edema through decreasing renal microvascular permeability via inhibition of the Cav-1/ eNOS pathway

Edema is one of the most typical symptoms of nephrotic syndrome. Increased vascular permeability makes a significant contribution to the progression of edema. Yue-bi-tang (YBT) is a traditional formula with excellent clinical efficacy in the treatment of edema. This study investigated the effect of YBT on renal microvascular hyperpermeability-induced edema in nephrotic syndrome and its mechanism. In our study, the content of target chemical components of YBT was identified using UHPLC-Q-Orbitrap HRMS analysis. A nephrotic syndrome model was replicated based on male Sprague-Dawley rats with Adriamycin (6.5 mg/kg) by tail vein injection. The rats were randomly divided into control, model, prednisone, and YBT (22.2 g/kg, 11.1 g/kg, and 6.6 g/kg) groups. After 14 d of treatment, the severity of renal microvascular permeability, edema, the degree of renal injury, and changes in the Cav-1/eNOS pathway were assessed. We found that YBT could regulate renal microvascular permeability, alleviate edema, and reduce renal function impairment. In the model group, the protein expression of Cav-1 was upregulated, whereas VE-cadherin was downregulated, accompanied by the suppression of p-eNOS expression and activation of the PI3K pathway. Meanwhile, an increased NO level in both serum and kidney tissues was observed, and the above situations were improved with YBT intervention. It thus indicates YBT exerts therapeutic effects on the edema of nephrotic syndrome, as it improves the hyperpermeability of renal microvasculature, and that YBT is engaged in the regulation of Cav-1/eNOS pathway-mediated endothelial function.

Pravastatin Improves Colonic and Hepatic Microcirculatory Oxygenation during Sepsis without Affecting Mitochondrial Function and ROS Production in Rats

Microcirculatory and mitochondrial dysfunction are considered the main mechanisms of septic shock. Studies suggest that statins modulate inflammatory response, microcirculation, and mitochondrial function, possibly through their action on peroxisome proliferator-activated receptor alpha (PPAR-α). The aim of this study was to examine the effects of pravastatin on microcirculation and mitochondrial function in the liver and colon and the role of PPAR-α under septic conditions. This study was performed with the approval of the local animal care and use committee. Forty Wistar rats were randomly divided into 4 groups: sepsis (colon ascendens stent peritonitis, CASP) without treatment as control, sepsis + pravastatin, sepsis + PPAR-α-blocker GW6471, and sepsis + pravastatin + GW6471. Pravastatin (200 µg/kg s.c.) and GW6471 (1 mg/kg) were applied 18 h before CASP-operation. 24 h after initial surgery, a relaparotomy was performed, followed by a 90 min observation period for assessment of microcirculatory oxygenation (μHbO2) of the liver and colon. At the end of the experiments, animals were euthanized, and the colon and liver were harvested. Mitochondrial function was measured in tissue homogenates using oximetry. The ADP/O ratio and respiratory control index (RCI) for complexes I and II were calculated. Reactive oxygen species (ROS) production was assessed using the malondialdehyde (MDA)-Assay. Statistics: two-way analysis of variance (ANOVA) + Tukey’s/Dunnett’s post hoc test for microcirculatory data, Kruskal–Wallis test + Dunn’s post hoc test for all other data. In control septic animals µHbO2 in liver and colon deteriorated over time (µHbO2: −9.8 ± 7.5%* and −7.6 ± 3.3%* vs. baseline, respectively), whereas after pravastatin and pravastatin + GW6471 treatment μHbO2 remained constant (liver: µHbO2 pravastatin: −4.21 ± 11.7%, pravastatin + GW6471: −0.08 ± 10.3%; colon: µHbO2 pravastatin: −0.13 ± 7.6%, pravastatin + GW6471: −3.00 ± 11.24%). In both organs, RCI and ADP/O were similar across all groups. The MDA concentration remained unchanged in all groups. Therefore, we conclude that under septic conditions pravastatin improves microcirculation in the colon and liver, and this seems independent of PPAR-α and without affecting mitochondrial function.

Integrated Proteomics and Metabolomics Analysis to Explore the Amelioration Mechanisms of Rosa roxburghii Tratt Fruit Polyphenols on Lipopolysaccharide-Induced Acute Lung Injury Mice

Acute lung injury (ALI) is the main cause of death for the elderly and children due to its high morbidity and mortality rates. Plant-derived functional foods are becoming increasingly important to the healthcare and food industries for adjunctive and alternative treatments of ALI. Polyphenols have been regarded to be beneficial to the prevention and amelioration of ALI. Rosa roxburghii Tratt fruit polyphenols (RRTP) has potential to prevent ALI, but mechanism remains unclear. This study was set up to systematically analyze the RRTP extract active ingredients, comprehensively evaluate its protective effects via lung histopathological examination, protein concentration, and cytokines production in ALI mice induced by lipopolysaccharide (LPS), and finally revealed alleviation mechanisms of the regulatory effects of RRTP by proteomics and metabolomics approach. The results demonstrated RRTP could synergistically exert significant preventive effects against ALI by notably ameliorating lung histopathological damage and pulmonary capillary permeability in ALI mice, inhibiting lung tissue inflammatory response and acute phase proteins and S-100 calcium binding proteins, suppressing excessive activation of complement and coagulation cascades, and regulating disordered lipids metabolism and amino acid metabolism. This study illustrated that RRTP has obvious advantages in ALI adjunctive therapy and revealed the complicated amelioration mechanisms, which provides a breakthrough for the development and demonstration of RRTP as a nutritional compound additive for complementary therapy of ALI.

Genetic Arg-304-His substitution in GRK5 protects against sepsis progression by alleviating NF-κB-mediated inflammation

BACKGROUND

Previous studies have demonstrated that G protein-coupled receptor kinase 5 (GRK5) exerts a pivotal regulatory effect on the inflammation associated with sepsis. The present study aimed to investigate the clinical association of GRK5 genetic variants with sepsis and to further explore the underlying genetic mechanisms involved in regulating sepsis-induced inflammatory responses and the pathogenesis of sepsis.

METHODS

This case-control study enrolled 1081 septic patients and 1147 matched controls for genotyping of GRK5 rs2230349 and rs2230345 polymorphisms. The effect of these genetic variants on GRK5-mediated inflammatory responses was analyzed in peripheral blood mononuclear cells (PBMCs) and THP-1 macrophages. A clinically relevant polymicrobial sepsis model was established by subjecting wild-type (WT) and GRK5-knockout mice to cecal ligation and puncture (CLP) to evaluate the role of GRK5 in sepsis.

RESULTS

We identified significant differences in the genotype/allele distribution of rs2230349 G > A, but not rs2230345, between the sepsis subtype and septic shock subgroups (GA + AA vs. GG genotype, OR = 0.698, 95% CI = 0.547-0.893, P = 0.004; A vs. G allele, OR = 0.753, 95% CI = 0.620-0.919, P = 0.005) and between the survivor and nonsurvivor subgroups (GA + AA vs. GG genotype, OR = 0.702, 95% CI = 0.531-0.929, P = 0.015; A vs. G allele, OR = 0.753, 95% CI = 0.298-0.949, P = 0.017). PBMCs carrying the sepsis-associated protective A allele produced significantly lower levels of TNF-α and IL-1β upon LPS stimulation. The results from the in vitro experiment showed that the Arg-304-His substitution caused by the rs2230349 G-to-A mutation in GRK5 significantly decreased the LPS-induced production of several proinflammatory cytokines, such as TNF-α, IL-6, IL-1β and MCP-1, via the IκB-α/NF-κB signaling pathway in THP-1 macrophages. Furthermore, GRK5-knockout mice exhibited a significant decrease in IκB-α phosphorylation/degradation, the p-p65/p65 ratio, the p-p50/p50 ratio, p65 nuclear translocation and downstream cytokine (TNF-α, IL-6, IL-1β and VCAM-1) production compared to WT mice after CLP surgery. A significant improvement in 7-day survival rate in GRK5-KO septic mice was observed in the presence of antibiotics.

CONCLUSIONS

The Arg-304-His substitution caused by the rs2230349 G-to-A mutation in GRK5 might disrupt GRK5 function and alleviate IKB-α/NF-κB-mediated inflammatory responses, which ultimately conferred a genetic protective effect against susceptibility to sepsis progression and mortality. These results may, to some extent, explain the heterogeneity of the clinical prognoses of septic patients and provide novel opportunities for individualized approaches for sepsis treatment.

High Concentration Hydrogen Mitigates Sepsis-Induced Acute Lung Injury in Mice by Alleviating Mitochondrial Fission and Dysfunction

Background: Multiple organ failure (MOF) is the main cause of early death in septic shock. Lungs are among the organs that are affected in MOF, resulting in acute lung injury. A large number of inflammatory factors and stress injury in sepsis can lead to alterations in mitochondrial dynamics. Numerous studies have confirmed that hydrogen can alleviate sepsis in the animal model. The purpose of this experiment was to explore the therapeutic effect of high concentration (67%) hydrogen on acute lung injury in septic mice and its mechanism. Methods: The moderate and severe septic models were prepared by cecal ligation and puncture. Hydrogen with different concentrations was inhaled for one hour at 1 h and 6 h after the corresponding surgery. The arterial blood gas of mice during hydrogen inhalation was monitored in real time, and the 7-day survival rate of mice with sepsis was recorded. The pathological changes of lung tissues and functions of livers and kidneys were measured. The changes of oxidation products, antioxidant enzymes and pro-inflammatory cytokines in lungs and serums were detected. Mitochondrial function was measured. Results: The inhalation of 2% or 67% hydrogen improves the 7-day survival rate and reduces acute lung injury as well as liver and kidney injury in sepsis. The therapeutic effect of 67% hydrogen inhalation on sepsis was related to increasing antioxidant enzyme activity, reducing oxidation products and pro-inflammatory cytokines in lungs and serums. Compared with the Sham group, mitochondrial dysfunction was alleviated in hydrogen groups. Conclusions: Hydrogen inhalation by high or low concentration can both significantly improve sepsis; however, a high concentration demonstrates a better protective effect. High concentration hydrogen inhalation can significantly improve the mitochondrial dynamic balance and reduce the lung injury in septic mice.

The protective effect of natural medicines against excessive inflammation and oxidative stress in acute lung injury by regulating the Nrf2 signaling pathway

Acute lung injury (ALI) is a common critical disease of the respiratory system that progresses into acute respiratory distress syndrome (ARDS), with high mortality, mainly related to pulmonary oxidative stress imbalance and severe inflammation. However, there are no clear and effective treatment strategies at present. Nuclear factor erythroid 2-related factor 2(Nrf2) is a transcription factor that interacts with multiple signaling pathways and regulates the activity of multiple oxidases (NOX, NOS, XO, CYP) related to inflammation and apoptosis, and exhibits antioxidant and anti-inflammatory roles in ALI. Recently, several studies have reported that the active ingredients of natural medicines show protective effects on ALI via the Nrf2 signaling pathway. In addition, they are cheap, naturally available, and possess minimal toxicity, thereby having good clinical research and application value. Herein, we summarized various studies on the protective effects of natural pharmaceutical components such as polyphenols, flavonoids, terpenoids, alkaloids, and polysaccharides on ALI through the Nrf2 signaling pathway and demonstrated existing gaps as well as future perspectives.

Role of Caveolin-1 in Sepsis – A Mini-Review

Sepsis is a generalized disease characterized by an extreme response to a severe infection. Moreover, challenges remain in the diagnosis, treatment and management of septic patients. In this mini-review we demonstrate developments on cellular pathogenesis and the role of Caveolin-1 (Cav-1) in sepsis. Studies have shown that Cav-1 has a significant role in sepsis through the regulation of membrane traffic and intracellular signaling pathways. In addition, activation of apoptosis/autophagy is considered relevant for the progression and development of sepsis. However, how Cav-1 is involved in sepsis remains unclear, and the precise mechanisms need to be further investigated. Finally, the role of Cav-1 in altering cell permeability during inflammation, in sepsis caused by microorganisms, apoptosis/autophagy activation and new therapies under study are discussed in this mini-review.

Neutrophil Membrane-Coated Therapeutic Liposomes for Targeted Treatment in Acute Lung Injury

Acute lung injury (ALI) is one of the most common comorbidities associated with sepsis and can lead to acute respiratory distress syndrome. Intense inflammatory response due to excessive activation and uncontrolled infiltration of neutrophils are the central processes in the development of sepsis-induced ALI. In this study, a biomimetic nanoplatform that is a neutrophil membrane-coated liposome-loaded acidic fibroblast growth factor (aFGF@NMLs), which can selectively target the inflamed lung and effectively alleviate sepsis-induced ALI via inflammation suppression, was constructed. In vitro findings revealed that aFGF@NMLs has pro-inflammatory cytokine binding capabilities and can promote cellular uptake, substantially attenuate inflammatory responses, and enhance cellular antioxidant capacity. The in vivo results show that aFGF@NMLs can specifically accumulate in injured lungs in ALI mice after intravenous injection, thereby reducing the secretion of pro-inflammatory cytokines, inhibiting pulmonary cell apoptosis, and promoting lung function recovery. In conclusion, aFGF@NMLs demonstrated anti-inflammatory effects, mitigated the progression of ALI, and contributed to the disease prognosis. This research offers an innovative strategy and concept for the clinical treatment of diseases related to pulmonary inflammation.

Dexmedetomidine protects against acute lung injury in mice via the DUSP1/MAPK/NF-κB axis by inhibiting miR-152-3p

OBJECTIVE

Acute lung injury (ALI) is a debilitating condition in clinics. Dexmedetomidine (Dex) is known for its anti-apoptotic and anti-inflammatory properties. This study attempted to investigate the protective mechanism of Dex in ALI mice.

METHODS

Mice were pretreated with Dex before model establishment by tracheal injection of lipopolysaccharide (LPS). Pulmonary function indexes and wet-to-dry (W/D) ratio were measured. Pulmonary pathological changes were observed through HE staining, CD31+-positive mouse pulmonary microvascular endothelial cells (MPMVECs) were counted through immunofluorescence staining, and apoptosis was detected through TUNEL staining. miR-152-3p mimic, sh-DUSP1, or p38 MAPK inhibitor was delivered into MPMVECs, followed by combined treatment of Dex and LPS. miR-152-3p expression, apoptosis, levels of apoptosis- and MAPK/NF-κB pathway-associated proteins, and inflammatory factors were measured through RT-qPCR, flow cytometry, Western blot, and ELISA. The binding relationship of miR-152-3p and DUSP1 was verified through bioinformatics software and dual-luciferase assay. ALI mouse model was established after injection of miR-152-3p antagomir.

RESULTS

Dex improved ALI mouse pulmonary function and mitigated injury in mice and MPMVECs. miR-125-3p overexpression or sh-DUSP1 partially abolished the protection of Dex on MPMVECs. miR-152-3p targeted DUSP1. sh-DUSP1 partially averted the protection of Dex on MPMVECs. Dex inhibited the activation of the MAPK/NF-κB pathway in MPMVECs mediated by LPS, which was partially reversed by sh-DUSP1. The p38 MAPK inhibitor SB203580 antagonized the protective effect of Dex on MPMVECs mediated by sh-DUSP1. Similarly, downregulation of miR-152-3p mitigated ALI via the DUSP1/MAPK/NF-κB axis in vivo.

CONCLUSION

Dex relieved ALI in mice via the DUSP1/MAPK/NF-κB axis by down-regulating miR-152-3p.

Suppression of NOD-like receptor protein 3 inflammasome activation and macrophage M1 polarization by hederagenin contributes to attenuation of sepsis-induced acute lung injury in rats

Acute lung injury (ALI) is a major leading cause of death in sepsis patients. Hederagenin (HG), derived from Hedera helix Linné, has anti-inflammatory effects, while its role in sepsis-induced ALI has not been elucidated. In vivo, rats were subjected to cecal ligation and puncture to induce ALI and then treated with HG (12.5, 25, or 50 mg/kg) by gavage. Administration of HG raised survival rate, ameliorated lung injury, and decreased lung wet/dry ratio and inflammatory cell accumulation in bronchoalveloar lavage fluid (BALF) of ALI rats. HG inhibited macrophage polarization toward the M1 phenotype as evidenced by decreased CD86 expression in rat lung tissues. Moreover, HG decreased the secretion of TNF-α, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in BALF and the levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lung tissues. In vitro, phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 macrophages were stimulated with 100 ng/mL lipopolysaccharide. HG treatment inhibited M1 macrophage polarization and the production of M1-related pro-inflammatory mediators (IL-6, MCP-1, iNOS, and COX-2). Mechanistically, HG inhibited NLRP3 inflammasome activation and subsequent release of IL-18 and IL-1β, and suppressed NF-κB signaling pathway both in vivo and in vitro. Notably, HG treatment further emphasized the inhibitory effect of NF-κB inhibitor BAY11-7082 on NLRP3 inflammasome activation and macrophage M1 polarization. Taken together, HG exerts a protective effect against sepsis-induced ALI by reducing the inflammatory response and macrophage M1 polarization, which may involve NF-κB pathway-modulated NLRP3 inflammasome activation.

Amelioration of Endotoxin-Induced Acute Lung Injury and Alveolar Epithelial Cells Apoptosis by Simvastatin Is Associated with Up-Regulation of Survivin/NF-kB/p65 Pathway

Disruption of the alveolar−endothelial barrier caused by inflammation leads to the progression of septic acute lung injury (ALI). In the present study, we investigated the beneficial effects of simvastatin on the endotoxin lipopolysaccharide (LPS)-induced ALI and its related mechanisms. A model of ALI was induced within experimental sepsis developed by intraperitoneal injection of a single non-lethal LPS dose after short-term simvastatin pretreatment (10−40 mg/kg orally). The severity of the lung tissue inflammatory injury was expressed as pulmonary damage scores (PDS). Alveolar epithelial cell apoptosis was confirmed by TUNEL assay (DNA fragmentation) and expressed as an apoptotic index (AI), and immunohistochemically for cleaved caspase-3, cytochrome C, and anti-apoptotic Bcl-xL, an inhibitor of apoptosis, survivin, and transcriptional factor, NF-kB/p65. Severe inflammatory injury of pulmonary parenchyma (PDS 3.33 ± 0.48) was developed after the LPS challenge, whereas simvastatin significantly and dose-dependently protected lung histology after LPS (p < 0.01). Simvastatin in a dose of 40 mg/kg showed the most significant effects in amelioration alveolar epithelial cells apoptosis, demonstrating this as a marked decrease of AI (p < 0.01 vs. LPS), cytochrome C, and cleaved caspase-3 expression. Furthermore, simvastatin significantly enhanced the expression of Bcl-xL and survivin. Finally, the expression of survivin and its regulator NF-kB/p65 in the alveolar epithelium was in strong positive correlation across the groups. Simvastatin could play a protective role against LPS-induced ALI and apoptosis of the alveolar−endothelial barrier. Taken together, these effects were seemingly mediated by inhibition of caspase 3 and cytochrome C, a finding that might be associated with the up-regulation of cell-survival survivin/NF-kB/p65 pathway and Bcl-xL.

Effects of molecular weight of chitosan on anti-inflammatory activity and modulation of intestinal microflora in an ulcerative colitis model

This study investigated the therapeutic effects and mechanisms of chitosans (CSs) with different molecular weights on ulcerative colitis (UC). Three size classes of CSs (Mw ≤ 3, 50, and 200 kDa) were used in this study. The effect of large CSs (Mw ≤ 200 kDa) on UC was the best, followed by that of medium CSs (Mw ≤ 50 kDa), and that of small CSs (Mw ≤ 3 kDa) was the least in the LPS-induced Raw 264.7 cell model and DSS-induced UC mice model. The therapeutic mechanisms of three CSs are related to anti-oxidation, anti-inflammation, and regulation of immunoglobulin and intestinal flora by attenuating body weight loss, decreasing the disease activity index (DAI) and MPO activity, suppressing proinflammatory cytokines and IgG levels, down-regulating the level of oxidative stress, increasing anti-inflammatory cytokines, SOD activity and Prevotellaceae_UCG-001 levels, and reducing the abundance of Proteobacteria, Actinobacteria, and Escherichia-Shigella. In general, the molecular weight of CSs influences their efficacy against UC. CSs with an optimal molecular weight demonstrate good development prospects for ameliorating UC.