LPS-induced Lung Injury Research Articles

Anti-inflammatory and antioxidant activities of Gymnema Sylvestre extract rescue acute respiratory distress syndrome in rats via modulating the NF-κB/MAPK pathway.

Acute respiratory distress syndrome (ARDS) is one of the major causes of mortality in COVID-19 patients, due to limited therapeutic options. This prompted us to explore natural sources to mitigate this condition. Gymnema Sylvestre (GS) is an ancient medicinal plant known to have various therapeutic effects. This investigation examined the therapeutic effect of hydroalcoholic extract of Gymnema Sylvestre (HAEGS) against lipopolysaccharide (LPS)-induced lung injury and ARDS in in vitro and in vivo models. UHPLC-HRMS/GC-MS was employed for characterizing the HAEGS and identified several active derivatives including gymnemic acid, gymnemasaponins, gymnemoside, gymnemasin, quercetin, and long fatty acids. Gene expression by RT-qPCR and DCFDA analysis by flow cytometry revealed that several inflammatory cytokine/chemokine, cell injury markers, and reactive oxygen species (ROS) levels were highly upregulated in LPS control and were significantly reduced upon HAEGS treatment. Consistent with the in vitro studies, we found that in LPS-induced ARDS model, pre-treatment with HAEGS significantly suppressed the LPS-induced elevation of inflammatory cell infiltrations, cytokine/chemokine marker expression, ROS levels, and lung injury in a dose-dependent manner. Further mechanistic studies demonstrated that HAEGS suppressed oxidative stress by modulating the NRF2 pathway and ameliorated the ARDS through the NF-κB/MAPK signalling pathway. Additional fractionation results revealed that fraction 6 which has the exclusive composition of gymnemic acid derivatives showed better anti-inflammatory effects (inhibition of IL-6 and IL-1β) at lower concentrations compared to HAEGS. Overall, HAEGS significantly mitigated LPS-induced lung injury and ARDS by targeting the NF-κB/MAPK signalling pathway. Thus, our work unravels the protective role of HAEGS for the first time in managing ARDS.

Inhibition of gp130 alleviates LPS-induced lung injury by attenuating apoptosis and inflammation through JAK1/STAT3 signaling pathway.

Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) is a life-threatening respiratory disease. Gp130 is a signal transduction receptor that participates in a variety of essential biological processes. The biological function of gp130 in ALI/ARDS is unclear. This study aims to investigate the roles and potential mechanisms of gp130 in lung injury induced by lipopolysaccharide (LPS). The ALI/ARDS mouse model was established using intratracheal LPS administration. Hematoxylin and eosin staining and bronchoalveolar lavage fluid analysis were used to evaluate the degree of lung injury. Cell apoptosis was assessed by TUNEL staining, flow cytometry, and western blot. Then the expression of gp130, IL-6, IL-10, TNF-α, and the JAK1/STAT3 signaling pathway-related proteins was assessed by RT-PCR, western blot, and immunohistochemistry. The expression of gp130 increased after 24h of LPS treatment. Inhibiting gp130 improved inflammatory infiltration and alveolar collapsed, decreased IL-6 and TNF-α levels, raised IL-10 levels, and decreased cell apoptosis in LPS-induced mice. Meanwhile, suppressing gp130 reduced the inflammatory response and cell apoptosis in LPS-induced Beas-2B cells. Furthermore, p-JAK1 and p-STAT3 expressions were elevated after LPS stimulation and decreased following gp130 inhibition, suggesting that gp130 may regulate the JAK1/STAT3 signaling pathway in LPS-induced mice and Beas-2B cells. The findings suggest that gp130 regulates the inflammatory response and cell apoptosis through the JAK1/STAT3 signaling pathway, thereby mitigating LPS-induced lung injury. Gp130 may be a potential therapeutic target for ALI/ARDS.

α1-adrenoceptor stimulation ameliorates lipopolysaccharide-induced lung injury by inhibiting alveolar macrophage inflammatory responses through NF-κB and ERK1/2 pathway in ARDS.

Catecholamines such as norepinephrine or epinephrine have been reported to participate in the development of acute respiratory distress syndrome (ARDS) by activating adrenergic receptors (ARs). But the role of α1-AR in this process has yet to be elucidated. In this study, ARDS mouse model was induced by intratracheal instillation of lipopolysaccharide. After treatment with α1-AR agonist phenylephrine or antagonist prazosin, lung pathological injury, alveolar barrier disruption and inflammation, and haemodynamic changes were evaluated. Cytokine levels and cell viability of alveolar macrophages were measured in vitro. Nuclear factor κB (NF-κB), mitogen-activated protein kinase, and Akt signalling pathways were analysed by western blot. It showed that α1-AR activation alleviated lung injuries, including reduced histopathological damage, cytokine expression, and inflammatory cell infiltration, and improved alveolar capillary barrier integrity of ARDS mice without influencing cardiovascular haemodynamics. In vitro experiments suggested that α1-AR stimulation inhibited secretion of TNF-α, IL-6, CXCL2/MIP-2, and promoted IL-10 secretion, but did not affect cell viability. Moreover, α1-AR stimulation inhibited NF-κB and enhanced ERK1/2 activation without significantly influencing p38, JNK, or Akt activation. Our studies reveal that α1-AR stimulation could ameliorate lipopolysaccharide-induced lung injury by inhibiting NF-κB and promoting ERK1/2 to suppress excessiveinflammatoryresponses of alveolar macrophages.

RmMANF prevents sepsis-associated lung injury via inhibiting endoplasmic reticulum stress-induced ferroptosis in mice

Ferroptosis plays a critical role in LPS-induced acute lung injury and is modulated by endoplasmic reticulum stress (ERS). As a typical ER stress-responsive protein, recently mesencephalic astrocyte-derived neurotrophic factor (MANF) has been demonstrated to attenuate LPS-induced acute lung injury (ALI) through repressing macrophage activation. However, whether MANF exerts a preventive role on ferroptosis and excess ER stress remains unclear. Here, we first built a protein-protein interaction (PPI) network to obtain potential interacting proteins related to MANF through STRING and GeneMANIA. Then, male C57BL/6J mice were used to build a model of LPS-induced lung injury. Two days before LPS injection, the tail vein injected recombinant murine MANF (rmMANF) at 750μg/kg. Twenty-four hours after the LPS injection, the histopathological changes and damage in the lung tissues were detected and scored by HE staining and TUNEL assay, respectively. Endogenous MANF levels, oxidative stress markers (GSH, SOD, CAT, and MDA), ERS markers (GRP78, PERK, and ATF4), and the ferroptosis markers (iron, GPX4, and 4-HNE) in the lung tissues were measured by IHC, western blotting, and commercial kits. Our results showed that LPS induced significant lung injury to the increase in MPO, MDA, and 4-HNE, a decrease in GPX4 and GSH, SOD, CAT, and total iron accumulation in LPS-exposed mice. Simultaneously, GRP78/PERK/ATF4 pathway was notably activated by LPS, accompanied by the down-regulation of MANF. Furthermore, rmMANF pretreatment markedly prevented LPS-induced lung tissue injury and ferroptosis characteristics with the increased GPX4 level in sepsis mice. Finally, we found that LPS-induced oxidative stress and activation of the GRP78/PERK/ATF4 pathway were significantly restrained by rmMANF pretreatment, except for endogenous MANF level. Overall, rmMANF pretreatment can prevent sepsis-associated lung injury by inhibiting ER stress-induced ferroptosis in mice.

Evaluation of GMP-manufactured pooled human umbilical cord-derived mesenchymal stem cells on lipopolysaccharide-induced lung injury in Sprague-Dawley rats

Evaluation of GMP-manufactured pooled human umbilical cord-derived mesenchymal stem cells on lipopolysaccharide-induced lung injury in Sprague-Dawley rats

PLD2 deletion alleviates disruption of tight junctions in sepsis-induced ALI by regulating PA/STAT3 phosphorylation pathway.

Increased inflammatory exudation caused by endothelium and endothelial junction damage is a typical pathological feature of acute respiratory distress syndrome/acute lung injury (ARDS/ALI). Previous studies have shown that phospholipase D2 (PLD2) can increase the inflammatory response and has a close relationship with the severity of sepsis-induced ALI and the mortality of sepsis, but its mechanism is unknown. This study explored the effect and mechanism of PLD2 deletion on the structure and function of endothelial tight junction (TJ) in lipopolysaccharide (LPS)-induced ALI. We used C57BL/6 mice (wild-type and PLD2 knockout (PLD2-/-)) and human umbilical vein endothelial cell (HUVEC) models of sepsis-ALI. The pathological changes were evaluated by hematoxylin-eosin staining. Pulmonary vascular permeability was detected using wet-dry ratio, fluorescein isothiocyanate (FITC)-dextran, FITC-albumin, and immunoglobulin M concentration of bronchoalveolar lavage fluid. FITC-dextran and trans-endothelial electrical resistance assay were used to evaluate endothelial permeability on LPS-stimulated HUVECs. The mRNA expressions of TJ proteins were detected by real-time quantitative polymerase chain reaction. Then, protein levels were detected through Western blot analysis and immunofluorescence. The content of phosphatidic acid (PA), a downstream product of PLD2, was detected using an enzyme-linked immunosorbent assay kit. PLD2 deficiency not only alleviated lung histopathological changes and improved pulmonary vascular permeability but also increased the survival rate of ALI mice. Knockout of PLD2 or treatment with the PLD2 inhibitor can reduce the damage of endothelial TJ proteins, namely, claudin5, occludin and zonula occludens protein-1, in sepsis-ALI mice and LPS-stimulated HUVECs. The level of the PLD2 catalytic product PA increased in LPS-stimulated HUVECs, and exogenous PA can reduce the TJ protein expression and increase signal transducer and activator of transcription 3 (STAT3) phosphorylation in vitro. Inhibition of STAT3 phosphorylation attenuated PA-induced degradation of endothelial TJs. PLD2 knockout or inhibition may protect against LPS-induced lung injury by regulating the PA/STAT3 phosphorylation/endothelial TJ axis.

Involvement of VEGFR1 signaling in LPS-induced lung injury in mice

Involvement of VEGFR1 signaling in LPS-induced lung injury in mice

Therapeutic effects of tea polyphenol-loaded nanoparticles coated with platelet membranes on LPS-induced lung injury.

Patients with ALI (acute lung injury)/ARDS (acute respiratory distress syndrome) are often septic and with poor prognosis, which leads to a high mortality rate of 25-40%. Despite the advances in medicine, there are no effective pharmacological therapies for ALI/ARDS due to the short systemic circulation and poor specificity in the lungs. To address this problem, we prepared TP-loaded nanoparticles (TP-NPs) through the emulsification-and-evaporation method, and then the platelet membrane vesicles were extracted and coated onto the surface of the NPs to constitute the biomimetic PM@TP-NPs. In a LPS-induced ALI mouse model, PM@TP-NPs showed good biocompatibility and biosafety, which was evidenced by no significant toxic effect on cell viability and no hemolysis of red blood cells. In ALI mice, the PM@TP-NPs showed favorable anti-inflammation and enhanced therapeutic activity of TPs compared to the free drug. Administration of PM@TP-NPs effectively inhibited lung vascular injury, evidenced by the decreased lung vascular permeability, reduced pro-inflammatory cytokine burden, evidenced by decreased inflammatory cell (macrophages, neutrophils, etc.) infiltration in the bronchoalveolar lavage fluid (BALF) and lung tissues, and inhibited the secretion of pro-inflammatory cytokines and NLRP3 inflammasome activation. ALI/ARDS is defined by damage to the alveolar epithelium and endothelium; thus, effective intervention targeting pulmonary vascular endothelial cells (VECs) is crucial for the treatment of respiratory diseases. For further determination of the targeting of PM cloaked NPs, healthy mice were also administered with the same NPs. Interestingly, the PM cloaked NPs only showed highly efficient targeting to the inflamed lungs and VECs, but no accumulation in healthy lungs and VECs. The data demonstrated that this biomimetic nanoplatform could be used as a potential strategy for personalized therapies in the treatment of inflammatory diseases, such as ALI/ARDS, and even COVID-19-associated pneumonia.

Recombinant Human Bone Morphogenetic Protein-2 Priming of Mesenchymal Stem Cells Ameliorate Acute Lung Injury by Inducing Regulatory T Cells.

Mesenchymal stromal/stem cells (MSCs) possess immunoregulatory properties and their regulatory functions represent a potential therapy for acute lung injury (ALI). However, uncertainties remain with respect to defining MSCs-derived immunomodulatory pathways. Therefore, this study aimed to investigate the mechanism underlying the enhanced effect of human recombinant bone morphogenic protein-2 (rhBMP-2) primed ES-MSCs (MSCBMP2) in promoting Tregs in ALI mice. MSC were preconditioned with 100 ng/ml rhBMP-2 for 24 h, and then administrated to mice by intravenous injection after intratracheal injection of 1 mg/kg LPS. Treating MSCs with rhBMP-2 significantly increased cellular proliferation and migration, and cytokines array reveled that cytokines release by MSCBMP2 were associated with migration and growth. MSCBMP2 ameliorated LPS induced lung injury and reduced myeloperoxidase activity and permeability in mice exposed to LPS. Levels of inducible nitric oxide synthase were decreased while levels of total glutathione and superoxide dismutase activity were further increased via inhibition of phosphorylated STAT1 in ALI mice treated with MSCBMP2. MSCBMP2 treatment increased the protein level of IDO1, indicating an increase in Treg cells, and Foxp3+CD25+ Treg of CD4+ cells were further increased in ALI mice treated with MSCBMP2. In co-culture assays with MSCs and RAW264.7 cells, the protein level of IDO1 was further induced in MSCBMP2. Additionally, cytokine release of IL-10 was enhanced while both IL-6 and TNF-α were further inhibited. In conclusion, these findings suggest that MSCBMP2 has therapeutic potential to reduce massive inflammation of respiratory diseases by promoting Treg cells.

Irbesartan eases lipopolysaccharide-induced lung injury In Vitro and In Vivo.

Acute lung injury (ALI) is classified as a devastating pulmonary disorder contributing to significant incidence and fatality rate. Irbesartan (IRB) is an angiotensin II receptor blocker that has been proposed to protect against oleic acid-induced ALI. To this end, the current study is concentrated on ascertaining the role of IRB in ALI and figuring out the probable action mechanism. First, cell counting kit-8 (CCK-8) appraised the viability of human pulmonary microvascular endothelial cells (HPMVECs) exposed to ascending concentrations of IRB. HPMVEC injury model and a mouse model of ALI induced by lipopolysaccharide (LPS) were pretreated by IRB. In vitro, cell viability was estimated by CCK-8 assay, and lactate dehydrogenase (LDH) release was tested by LDH assay kit. Enzyme-linked immunosorbent assay (ELISA) and Western blotting estimated the expression levels of inflammatory factors. Fluorescein isothiocyanate-dextran was used to assess HPMVEC permeability. Western blotting examined the expression of adherent and tight junction proteins. In vivo, hematoxylin and eosin staining evaluated lung tissue damage and lung wet/dry (W/D) weight was measured. ELISA analyzed the levels of inflammatory factors in the serum and bronchoalveolar lavage fluid (BALF), and Western blotting examined the expression of inflammatory factors. The total cell, neutrophil, and macrophage numbers in BALF were determined using a cell counter. Lung capillary permeability was assayed by Evans blue albumin and total protein concentration in BALF was measured using bicinchoninic acid method. Immunofluorescence assay and Western blotting examined the expression of adherent and tight junction proteins in lung tissues. It was observed that IRB dose-dependently enhanced the viability while reduced LDH release, inflammatory response as well as permeability in LPS-challenged HPMVECs in vitro. In addition, LPS-stimulated lung tissue damage, pulmonary edema, inflammatory response as well as lung capillary permeability in vivo were all reversed following IRB treatment. Collectively, IRB treatment might elicit protective behaviors against LPS-triggered ALI.

Astaxanthin alleviates lipopolysaccharide-induced acute lung injury by suppressing ferroptosis.

Background: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening disorders with a high risk of mortality. Astaxanthin (AST) is a supernatural antioxidant that has been extensively studied due to its role in immunomodulation, oxidative stress, and lipid peroxidation. However, the association between ferroptosis and AST is not well understood. The purpose of this study is to explore the regulatory role of AST on ferroptosis in lipopolysaccharide (LPS)-induced ALI. Methods: We established an MLE-12 cell injury model and a mouse ALI model by treating with LPS. The levels of IL-6, TNF-α, and IL-1β in the mouse serum were measured using an enzyme-linked immunosorbent assay. Moreover, immunohistochemical, immunofluorescence, western blot, and quantitative real-time polymerase chain reaction analyses were conducted to examine the effects of AST and ferrostatin-1. Results: We discovered that AST pretreatment greatly alleviated LPS-induced lung injury and inhibited ferroptosis, which was demonstrated by a decrease in the accumulation of malondialdehyde and Fe2+ and an increase in the levels of glutathione and glutathione peroxidase 4 in the lung tissues of ALI mice and MLE-12 cells. Additionally, we found that AST also evidently suppressed ferritinophagy by upregulation of ferritin and downregulation of nuclear receptor co-activator 4 (NCOA4) in MLE-12 cells. Conclusions: AST pretreatment could lead to a relief of LPS-induced ALI, perhaps via suppressing ferroptosis, and could also reduce unstable iron accumulation by inhibiting NCOA4-mediated ferritin phagocytosis from mitigating lipid peroxidation and ferroptosis in lung epithelial cells.

Erythropoietin inhibits neutrophil extracellular traps formation to ameliorate lung injury in a pneumonia model.

Severe pneumonia is a kind of disease that develops from lung inflammation, and new drugs are still required to treat the same. Erythropoietin (EPO) is widely used to treat anemia in patients. However, there are fewer studies on the role of EPO in neutrophil extracellular trappings (NETs) and pneumonia, and the mechanism is unclear. To investigate the possible effects of EPO on the formation of NETs and progression of pneumonia. Mice pneumonia model was induced by tracheal lipopolysaccharide (LPS) administration. Hematoxylin and eosin (H&E) staining and automatic blood cell analysis were performed in this model to confirm the effects of EPO on lung injury. Flow cytometry, enzyme-linked immunosorbent serological assay, and immunostaining assay were conducted to detect the effects of EPO on the inflammation as well as formation of NETs in mice. Immunoblot was further conducted to confirm the mechanism. EPO alleviated LPS-induced lung injury. EPO reduced the release of inflammatory factors induced by LPS. In addition, EPO inhibited the formation of NETs. Mechanically, EPO inhibited tumor necrosis factor (TNF) receptor associated factor 2 (TRAF2)/nuclear factor kappa-B (NF-κB) activity in mouse models, and therefore suppressed the progression of pneumonia. EPO inhibited formation of NETs to ameliorate lung injury in a pneumonia model, and could serve as a drug of pneumonia.

Distinct Transcriptional and Functional Differences of Lung Resident and Monocyte-Derived Alveolar Macrophages During the Recovery Period of Acute Lung Injury.

In acute lung injury, two subsets of lung macrophages exist in the alveoli: tissue-resident alveolar macrophages (AMs) and monocyte-derived alveolar macrophages (MDMs). However, it is unclear whether these 2 subsets of macrophages have different functions and characteristics during the recovery phase. RNA-sequencing of AMs and MDMs from the recovery period of LPS-induced lung injury mice revealed their differences in proliferation, cell death, phagocytosis, inflammation and tissue repair. Using flow cytometry, we found that AMs showed a higher ability to proliferate, whereas MDMs expressed a larger amount of cell death. We also compared the ability of phagocytosing apoptotic cells and activating adaptive immunity and found that AMs have a stronger ability to phagocytose, while MDMs are the cells that activate lymphocytes during the resolving phase. By testing surface markers, we found that MDMs were more prone to the M1 phenotype, but expressed a higher level of pro-repairing genes. Finally, analysis of a publicly available set of single-cell RNA-sequencing data on bronchoalveolar lavage cells from patients with SARS-CoV-2 infection validated the double-sided role of MDMs. Blockade of inflammatory MDM recruitment using CCR2-/- mice effectively attenuates lung injury. Therefore, AMs and MDMs exhibited large differences during recovery. AMs are long-lived M2-like tissue-resident macrophages that have a strong ability to proliferate and phagocytose. MDMs are a paradoxical group of macrophages that promote the repair of tissue damage despite being strongly pro-inflammatory early in infection, and they may undergo cell death as inflammation fades. Preventing the massive recruitment of inflammatory MDMs or promoting their transition to pro-repairing phenotype may be a new direction for the treatment of acute lung injury.

Early mechanisms of neutrophil activation and transmigration in acute lung injury.

Introduction:Neutrophil transmigration is multifactorial and primarily driven by selectins and β2-integrins (CD11b/CD18), whose expression are dependent on the underlying stimulus. Ventilator-induced lung injury (VILI) results in a predominantly CD18-independent mechanism of neutrophil recruitment, while direct endotoxin-induced lung injury results from a CD18-dependent mechanism. We previously observed that lack of NADPH oxidases DUOX1 and DUOX2 resulted in reduced neutrophil influx in a VILI model of lung injury but had no influence on neutrophil influx after LPS exposure. Based on these observations, we hypothesized that DUOX1/DUOX2 are an important component of CD18-independent mechanisms of neutrophil recruitment in the lung. Methods:We exposed Duoxa -/- (KO) mice and Duoxa +/+ (WT) mice to either an intratracheal exposure of lipopolysaccharide (LPS/endotoxin)-or high tidal volume ventilation and compared expression of neutrophil markers between groups. WT mice (129S6/SvEvTac) were obtained from Taconic Biosciences (One Discovery Drive Suite 304; Rensselaer, NY 1244) and were allowed to acclimatize for one week prior to study enrollment. KO mice were generated as previously described [Grasberger 2012] and bred in-house on a 129S6 background. We provided positive-pressure ventilation at a tidal volume of 10ml/kg with 2 cmH20 positive end-expiratory pressure (PEEP). Mice were assigned to groups consisting of KO (n = 5) and WT (n = 5) in each group and divided into non-ventilated, positive-pressure ventilation, or LPS IT exposure groups. Positive-pressure ventilation was instituted for 4-h using a FlexiVent (Flexiware 8.1, Scireq, Montreal, QC, Canada). Lipopolysaccharide (Salmonella enterica serotype tryphimurium L6143, Millipore Sigma) was administered via an intratracheal (IT) route at a dose of 0.1mg/kg. Mice were humanely euthanized at 4-h post-injection consistent with the UC Davis IAUCAC-approved protocol. Results:As previously observed, neutrophilic influx into the airways was significantly impaired in the Duoxa -/- (KO) mice after VILI, but not after LPS exposure. LPS-induced lung injury resulted in upregulation of CD11b+ neutrophils and shedding of CD62L and CD162 regardless of DUOX expression, whereas VILI resulted in upregulation of CD49+ neutrophils in the Duoxa +/+ (WT) mice but not the Duoxa -/- (KO) mice. Conclusion:Our data suggest DUOX is required for CD18-independent mechanisms of neutrophil recruitment in the lung induced by acute lung injury, but not for canonical CD18depedent mechanisms after LPS exposure.

Guettarda crispiflora Vahl Methanol Extract Ameliorates Acute Lung Injury and Gastritis by Suppressing Src Phosphorylation.

Many species in the genus Guettarda are known to exert anti-inflammatory effects and are used as traditional medicinal plants to treat various inflammatory symptoms. However, no studies on the inflammatory activities of Guettarda crispiflora Vahl have been reported. The aim of the study was to investigate in vitro and in vivo the anti-inflammatory effects of a methanol extract of Guettarda crispiflora Vahl (Gc-ME). To determine the anti-inflammatory activity of Gc-ME, lipopolysaccharide (LPS)-, poly(I:C)-, or Pam3CSK4-treated RAW264.7 cells, HCl/EtOH- and LPS-treated mice were employed for in vitro and in vivo tests. LPS-induced nitric oxide production in RAW264.7 cells was determined by Griess assays and cytokine gene expression in LPS-activated RAW264.7 cells, confirmed by RT- and real-time PCR. Transcriptional activation was evaluated by luciferase reporter gene assay. Target protein validation was assessed by Western blot analysis and cellular thermal shift assays (CETSA) with LPS-treated RAW264.7 and gene-transfected HEK293 cells. Using both a HCl/EtOH-induced gastritis model and an LPS-induced lung injury model, inflammatory states were checked by scoring or evaluating gastric lesions, lung edema, and lung histology. Phytochemical fingerprinting of Gc-ME was observed by using liquid chromatography-mass spectrometry. Nitric oxide production induced by LPS and Pam3CSK4 in RAW264.7 cells was revealed to be reduced by Gc-ME. The LPS-induced upregulation of iNOS, COX-2, IL-6, and IL-1β was also suppressed by Gc-ME treatment. Gc-ME downregulated the promotor activities of AP-1 and NF-κB triggered by MyD88- and TRIF induction. Upstream signaling proteins for NF-κB activation, namely, p-p50, p-p65, p-IκBα, and p-Src were all downregulated by Ch-EE. Moreover, Src was revealed to be directly targeted by Gc-ME. This extract, orally treated strongly, attenuated the inflammatory symptoms in HCl/EtOH-treated stomachs and LPS-treated lungs. Therefore, these results strongly imply that Guettarda crispiflora can be developed as a promising anti-inflammatory remedy with Src-suppressive properties.

Piperlongumine mitigates LPS-induced inflammation and lung injury via targeting MD2/TLR4

PurposeAcute lung injury (ALI) is a fatal acute inflammatory illness with restricted therapeutic choices clinically. Piperlongumine (PL) is recognized as an alkaloid separated from Piper longum L, which was suggested to exhibit multiple pharmacological activities (e.g., anti-inflammatory activity). However, the effects of PL on LPS-triggered ALI and its anti-inflammatory target remain unclear. This paper intended to assess the roles of PL in LPS-triggered ALI, as well as its underlying mechanism and target. MethodsIn vivo, ALI was induced by intratracheal injection of LPS to evaluate protective effects of PL and assessed by the changes of histopathological. In vitro, the anti-inflammatory activity and mechanism of PL were investigated by ELISA, RT-qPCR, transcription factor enrichment analysis, Western blotting and Immunofluorescence assay. The binding affinity of PL to MD2 was analyzed using computer docking, surface plasmon resonance, ELISA and immunoprecipitation assay. ResultsIt was reported here that PL treatment alleviated LPS-induced pulmonary damage, inflammatory cells infiltration and inflammatory response in mice. In culture cells, PCR array showed that PL significantly inhibited LPS-induced inflammatory cytokines, chemokines, and type I IFNs genetic expression, along with the inhibition of TAK1 and TBK1 pathway. It is noteworthy that PL is capable of straightly binding to MD2 and inhibiting MD2/TLR4 complex formation and TLR4 dimerization. ConclusionsAs revealed from this study, PL directly binding to MD2 to block cytokines expression by inhibiting the activation of TAK1 and TBK1 pathway, which then exerted its pulmonary protective activity. Accordingly, PL may act as an underlying candidate for treating LPS-triggered ALI.

Mesenchymal stromal/stem cells: breaking the deadlock in the treatment of multiple organ dysfunction syndrome

Mesenchymal stromal/stem cells: breaking the deadlock in the treatment of multiple organ dysfunction syndrome

Beneficial effects of CCL8 inhibition at lipopolysaccharide-induced lung injury.

CCL8 (MCP-2) is a chemoattractive cytokine associated with various immune-related pathologies. Recent studies show that CCL8 is significantly stimulated during acute respiratory distress syndrome in severely ill patients with COVID-19, making the inhibition of CCL8 activity a promising treatment. Lipopolysaccharide (LPS)-induced lung injury was evaluated in mice using a neutralizing antibody (1G3E5) against human CCL8. Pharmacokinetic studies indicated that following IP administration, 1G3E5 was sustained at higher levels and for a longer period compared to IV administration. CCL8 expression in the lungs was not enhanced by LPS, but CCR2 and CCR5 receptors were significantly stimulated. 1G3E5-mediated inhibition of CCL8 was associated with the reduction of pulmonary inflammation and suppression of various pro-inflammatory cytokines. These results point to a previously unrecognized, permissive role for CCL8 in mediating cytokine induction and ultimately sustaining inflammation. Disruption of CCL8 activity may provide a strategy for mitigating pulmonary inflammation during lung injury when related to abnormal cytokine induction.

Cupping alleviates lung injury through the adenosine/A2BAR pathway

BackgroundAcute lung injury (ALI) is a serious condition. Inflammation plays a crucial role in the pathogenesis of ALI. Cupping, as a part of traditional Chinese medicine, is still a popular complementary and alternative therapy for a variety of ailments including respiratory diseases. However, reliable scientific data about cupping therapy are scarce. Adenosine, a purine nucleoside produced under metabolic stress by the action of extracellular ectonucleotidases (i.e. CD39 and CD73), can attenuate ALI through the A2BAR receptor. The aim of this study was to investigate the protective effect of cupping in a rat model of ALI and the role of adenosine in it. MethodsMale adult rats were subjected to ALI by intratracheal LPS instillation (0.3 mg/kg). Immediately after intratracheal LPS instillation, vacuum pressure was applied to a sanitized plastic bell cup on the back of the rat by suction for 10 min. Pulmonary injury and inflammation were assessed at 4 h after LPS challenge. The role of adenosine and A2BAR in cupping's protection after LPS instillation were evaluated. ResultsCupping alleviated LPS-induced lung injury, reduced inflammation and inhibited NF-kB activation in rats. Cupping upregulated CD39 and CD73 mRNA expression of the skin tissue at the cupping site and increased circulating levels of adenosine. Administration of PSB1115, a specific adenosine A2BAR receptor antagonist, abolished cupping's beneficial effects in LPS-induced ALI. ConclusionsCupping attenuates lung inflammation and injury through the adenosine/A2BAR pathway. The current study provides evidence-based information about cupping therapy in ALI.

Small extracellular vesicles derived from Nrf2-overexpressing human amniotic mesenchymal stem cells protect against lipopolysaccharide-induced acute lung injury by inhibiting NLRP3

BackgroundAcute lung injury (ALI) is a major cause of respiratory failure in critically ill patients that results in significant morbidity and mortality. Recent studies indicate that cell-based therapies may be beneficial in the treatment of ALI. We recently demonstrated that Nrf2-overexpressing human amniotic mesenchymal stem cells (hAMSCs) reduce lung injury, fibrosis and inflammation in lipopolysaccharide (LPS)-challenged mice. Here we tested whether small extracellular vesicles (sEVs) derived from Nrf2-overexpressing hAMSCs (Nrf2-sEVs) could protect against ALI. sEVs were isolated from hAMSCs that overexpressed (Nrf2-sEVs) or silenced (siNrf2-sEVs) Nrf2. We examined the effects of sEVs treatment on lung inflammation in a mouse model of ALI, where LPS was administered intratracheally to mice, and lung tissues and bronchoalveolar lavage fluid (BALF) were analyzed 24 h later.MethodsHistological analysis, immunofluorescence microscopy, western blotting, RT-PCR and ELISA were used to measure the inflammatory response in the lungs and BALF.ResultsWe found that sEVs from hAMSCs are protective in ALI and that Nrf2 overexpression promotes protection against lung disease. Nrf2-sEVs significantly reduced lung injury in LPS-challenged mice, which was associated with decreased apoptosis, reduced infiltration of neutrophils and macrophages, and inhibition of pro-inflammatory cytokine expression. We further show that Nrf2-sEVs act by inhibiting the activation of the NLRP3 inflammasome and promoting the polarization of M2 macrophages.ConclusionOur data show that overexpression of Nrf2 protects against LPS-induced lung injury, and indicate that a novel therapeutic strategy using Nrf2-sEVs may be beneficial against ALI.