LPS-induced Lung Inflammation Research Articles

IRG1/ACOD1 Promotes Neutrophil Reverse Migration and Alleviates Local Inflammation.

Polymorphonuclear neutrophil (PMN) infiltration at inflammatory site plays a critical role in inflammation. PMN reverse migration (rM) describes the phenomenon that PMNs migrate away from inflammatory site back into the vasculature, and its role within inflammatory scenarios remains to be fully determined. This study aimed to investigate the mechanism underlying PMN rM and its role in inflammation. First, we demonstrated PMN rM in a mouse model of LPS-induced acute lung inflammation. By single-cell RNA sequencing (scRNA-seq), we demonstrated that reverse migrated (rM-ed) PMNs in blood expressed high level of immuneresponsive gene 1 (Irg1), the encoding gene of cis-aconitate decarboxylase (ACOD1). Using a mouse air pouch model, which enables us to directly track rM-ed PMNs in vivo, we detected higher expression of ACOD1 in the rM-ed PMNs in circulation. Furthermore, mice with Irg1 knockout exhibited decreased PMN rM and higher levels of inflammatory cytokine in inflammatory site. Mechanistically, we found that itaconate, the product of ACOD1 catalyzation, decreased PMN ICAM-1 expression at the inflammation site. Furthermore, inflammatory site showed a high level of shed CD11a, the ligand of ICAM-1. Neutralization of either ICAM-1 or CD11a leading to increased PMN rM. These findings suggest that the binding of ICAM-1 and shed CD11a serves as a retaining force to hold PMNs in the site of inflammation, and ACOD1-decreased PMN surface expression of ICAM-1 weakens the retaining force, so promoting PMNs to leave the inflammatory site. These results indicate a regulatory role of IRG1 in PMN rM and subsequent contributions to inflammation resolution.

Trichinella spiralis alleviates LPS-induced acute lung injury by modulating the protective Th2 immune response

Sepsis is a disorder of immune regulation caused by pathogenic microorganisms. A large number of inflammatory factors and inflammatory mediators are released, resulting in systemic inflammatory response disorder and acute lung injury (ALI). Helminths infection activate Th2 cytokines and immunomodulatory pathways, which have the function of anti-infection effector molecules. The early infection of Trichinella spiralis (T. spiralis) was mainly intestinal phase. In this study, we explored the effect of intestinal phase infection of T. spiralis on LPS-induced ALI. Compared with control mice, the serum and lung tissues of T. spiralis infected mice had a significant decrease of Th1 inflammatory cytokines, a significant increase of Th2 anti-inflammatory cytokines, and a significant decrease of inflammatory cell infiltration in lung tissue. These results suggest that T. spiralis during the intestinal phase can act on distal organs (lung) and reduce LPS-induced lung inflammation, providing evidence for a potential new pathway for immune-mediated disease in helminths and a possible role for intestinal worms in the gut-lung axis.

Eugenol Inhibits Neutrophils Myeloperoxidase In Vitro and Attenuates LPS-Induced Lung Inflammation in Mice.

Eugenol (Eug) is a polyphenol extracted from the essential oil of Syzygium aromaticum (L.) Merr. and Perry (Myrtaceae). The health benefits of eugenol in human diseases were proved in several studies. This work aims to evaluate the effect of eugenol on lung inflammatory disorders. For this, using human neutrophils, the antioxidant activity of eugenol was investigated in vitro. Furthermore, a model of LPS-induced lung injury in mice was used to study the anti-inflammatory effect of eugenol in vivo. Results showed that eugenol inhibits luminol-amplified chemiluminescence of resting neutrophils and after stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLF) peptide or phorbol myristate acetate (PMA). This effect was dose dependent and was significant from a low concentration of 0.1 µg/mL. Furthermore, eugenol inhibited myeloperoxidase (MPO) activity without affecting its degranulation. Eugenol has no scavenging effect on hydrogen peroxide (H2O2) and superoxide anion (O2-). Pretreatment of mice with eugenol prior to the administration of intra-tracheal LPS significantly reduced neutrophil accumulation in the bronchoalveolar lavage fluid (BALF) and decreased total proteins concentration. Moreover, eugenol clearly inhibited the activity of matrix metalloproteinases MMP-2 (21%) and MMP-9 (28%), stimulated by LPS administration. These results suggest that the anti-inflammatory effect of eugenol against the LPS-induced lung inflammation could be exerted via inhibiting myeloperoxidase and metalloproteinases activity. Thus, eugenol could be a promising molecule for the treatment of lung inflammatory diseases.

GSTP alleviates acute lung injury by S-glutathionylation of KEAP1 and subsequent activation of NRF2 pathway

Oxidative stress plays an important role in the pathogenesis of acute lung injury (ALI). As a typical post-translational modification triggered by oxidative stress, protein S-glutathionylation (PSSG) is regulated by redox signaling pathways and plays diverse roles in oxidative stress conditions. In this study, we found that GSTP downregulation exacerbated LPS-induced injury in human lung epithelial cells and in mice ALI models, confirming the protective effect of GSTP against ALI both in vitro and in vivo. Additionally, a positive correlation was observed between total PSSG level and GSTP expression level in cells and mice lung tissues. Further results demonstrated that GSTP inhibited KEAP1-NRF2 interaction by promoting PSSG process of KEAP1. By the integration of protein mass spectrometry, molecular docking, and site-mutation validation assays, we identified C434 in KEAP1 as the key PSSG site catalyzed by GSTP, which promoted the dissociation of KEAP1-NRF2 complex and activated the subsequent anti-oxidant genes. In vivo experiments with AAV-GSTP mice confirmed that GSTP inhibited LPS-induced lung inflammation by promoting PSSG of KEAP1 and activating the NRF2 downstream antioxidant pathways. Collectively, this study revealed the novel regulatory mechanism of GSTP in the anti-inflammatory function of lungs by modulating PSSG of KEAP1 and the subsequent KEAP1/NRF2 pathway. Targeting at manipulation of GSTP level or activity might be a promising therapeutic strategy for oxidative stress-induced ALI progression.

Fortunellin ameliorates LPS-induced acute lung injury, inflammation, and collagen deposition by restraining the TLR4/NF-κB/NLRP3 pathway.

Acute lung injury (ALI) is the prevalent respiratory disease of acute inflammation with high morbidity and mortality. Fortunellin has anti-inflammation property, but its role in ALI remains elusive. Thus, this study clarified the function of fortunellin on ALI pathogenesis. The ALI mouse model was established by lipopolysaccharide (LPS) induction, and lung tissue damage was evaluated utilizing hematoxylin-eosin (HE) staining. The edema of lung tissue was measured by the lung wet/dry (W/D) ratio. The lung capillary permeability was reflected by the protein content in bronchoalveolar lavage fluid (BALF). Inflammatory cell infiltration was measured by the evaluation of the content of myeloperoxidase (MPO), neutrophils, and leukocytes in BALF. Cell apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The secretions of inflammatory cytokines were quantified using enzyme-linked immunosorbent assay (ELISA) assays. Lung tissue collagen deposition was evaluated by Masson staining. Fortunellin attenuated LPS-induced lung tissue damage and reduced the W/D ratio, the content of MPO in lung tissue, the total protein contents in BALF, and the neutrophils and leukocytes number. Besides, fortunellin alleviated LPS-stimulated lung tissue apoptosis, inflammatory response, and collagen deposition. Furthermore, Fortunellin repressed the activity of the Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB)/NLR Family Pyrin Domain Containing 3 (NLRP3) pathway in the LPS-stimulated ALI model and LPS-induced RAW264.7 cells. Moreover, fortunellin attenuated LPS-stimulated tissue injury, apoptosis, inflammation, and collagen deposition of the lung via restraining the TLR4/NF-κB/NLRP3 pathway. Fortunellin attenuated LPS-stimulated ALI through repressing the TLR4/NF-κB/NLRP3 pathway. Fortunellin may be a valuable drug for ALI therapy.

Bik promotes proteasomal degradation to control low-grade inflammation.

Although chronic low-grade inflammation does not cause immediate clinical symptoms, over the longer term, it can enhance other insults or age-dependent damage to organ systems and thereby contribute to age-related disorders, such as respiratory disorders, heart disease, metabolic disorders, autoimmunity, and cancer. However, the molecular mechanisms governing low-level inflammation are largely unknown. We discovered that Bcl-2-interacting killer (Bik) deficiency causes low-level inflammation even at baseline and the development of spontaneous emphysema in female but not male mice. Similarly, a single nucleotide polymorphism that reduced Bik levels was associated with increased inflammation and enhanced decline in lung function in humans. Transgenic expression of Bik in the airways of Bik-deficient mice inhibited allergen- or LPS-induced lung inflammation and reversed emphysema in female mice. Bik deficiency increased nuclear but not cytosolic p65 levels because Bik, by modifying the BH4 domain of Bcl-2, interacted with regulatory particle non-ATPase 1 (RPN1) and RPN2 and enhanced proteasomal degradation of nuclear proteins. Bik deficiency increased inflammation primarily in females because Bcl-2 and Bik levels were reduced in lung tissues and airway cells of female compared with male mice. Therefore, controlling low-grade inflammation by modifying the unappreciated role of Bik and Bcl-2 in facilitating proteasomal degradation of nuclear proteins may be crucial in treating chronic age-related diseases.

Mesenchymal Stem Cell-derived Type II Alveolar Epithelial Progenitor Cells Attenuate LPS-induced Acute Lung Injury and Reduce P63 Expression.

Acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) is a severe clinical respiratory-failure disease mainly characterized by acute damage to the alveolar epithelium and pulmonary vascular endothelial cells. Stem cell therapy has emerged as a potential regenerative strategy for ARDS/ALI, however, the outcome is limited, and the underlying mechanisms are unclear. We established a differentiation system for bone marrow-derived mesenchymal stem cellderived (BM-MSC) type II alveolar epithelial progenitor cells (AECIIs) and assessed their regulatory effects on lipopolysaccharide (LPS)-induced ALI. We induced BM-MSC differentiation into AECIIs using a specific conditioned medium. After 26 days of differentiation, 3×105 BM-MSC-AECIIs were used to treat mice with LPS-induced ALI through tracheal injection. After tracheal injection, BM-MSC-AECIIs migrated to the perialveolar area and reduced LPSinduced lung inflammation and pathological injury. RNA-seq suggested that P63 protein was involved in the effects of BM-MSC-AECIIs on lung inflammation. Our results suggest that BM-MSC-AECIIs may reduce LPS-induced acute lung injury by decreasing P63 expression.

Magnolia kobus DC leaf ethanol extract alleviated lipopolysaccharide-induced acute lung inflammation by suppressing NF-κB and Nrf2 signaling

Introduction: Magnolia kobus DC has been used as herbal medicine to treat coughs and is known to exert biological effects such as anti-inflammatory, antioxidant, and antibacterial properties. We aimed to define the pharmacological effects of M. kobus leaf ethanol extract (MLEE) on acute lung inflammation and explore the underlying mechanisms of action. Methods: For in vitro investigations, RAW 264.7 cells were pretreated with MLEE (1, 10, and 100 μg/mL) and stimulated with lipopolysaccharide (LPS). For in vivo investigations, BALB/c mice were intratracheally administered with LPS for 24 hours after injection of MLEE (0.3, 3, and 30 mg/kg). Hematoxylin and eosin staining was used for histopathology analysis of lung tissue. The phytochemical constituents of MLEE were analyzed using high-performance liquid chromatography. Results: In RAW 264.7 cells, MLEE reduced the activation of the inflammatory mediators (inducible nitric oxide synthase and cyclooxygenase-2) and the nuclear translocation of nuclear factor (NF)-κB and nuclear factor erythroid-2-related factor 2 (Nrf2). The intraperitoneal injection of MLEE (30 mg/kg) attenuated interstitial edema and immune cell infiltration in LPS-induced acute lung inflammation. MLEE also inhibited the activation of cyclooxygenase-2, NF-κB, and Nrf2 in the lung tissue. Conclusion: Taken together, MLEE exerted an anti-inflammatory effect by inhibiting inflammatory and oxidative mediators on acute lung inflammation suggesting that it might be used as a natural drug for treating acute lung inflammatory diseases.

Blocking P2Y2 purinergic receptor prevents the development of lipopolysaccharide-induced acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality resulting from a direct or indirect injury of the lung. It is characterized by a rapid alveolar injury, lung inflammation with neutrophil accumulation, elevated permeability of the microvascular-barrier leading to an aggregation of protein-rich fluid in the lungs, followed by impaired oxygenation in the arteries and eventual respiratory failure. Very recently, we have shown an involvement of the Gq-coupled P2Y2 purinergic receptor (P2RY2) in allergic airway inflammation (AAI). In the current study, we aimed to elucidate the contribution of the P2RY2 in lipopolysaccharide (LPS)-induced ARDS mouse model. We found that the expression of P2ry2 in neutrophils, macrophages and lung tissue from animals with LPS-induced ARDS was strongly upregulated at mRNA level. In addition, ATP-neutralization by apyrase in vivo markedly attenuated inflammation and blocking of P2RY2 by non-selective antagonist suramin partially decreased inflammation. This was indicated by a reduction in the number of neutrophils, concentration of proinflammatory cytokines in the BALF, microvascular plasma leakage and reduced features of inflammation in histological analysis of the lung. P2RY2 blocking has also attenuated polymorphonuclear neutrophil (PMN) migration into the interstitium of the lungs in ARDS mouse model. Consistently, treatment of P2ry2 deficient mice with LPS lead to an amelioration of the inflammatory response showed by reduced number of neutrophils and concentrations of proinflammatory cytokines. In attempts to identify the cell type specific role of P2RY2, a series of experiments with conditional P2ry2 knockout animals were performed. We observed that P2ry2 expression in neutrophils, but not in the airway epithelial cells or CD4+ cells, was associated with the inflammatory features caused by ARDS. Altogether, our findings imply for the first time that increased endogenous ATP concentration via activation of P2RY2 is related to the pathogenesis of LPS-induced lung inflammation and may represent a potential therapeutic target for the treatment of ARDS and predictably assess new treatments in ARDS.

Knockdown of Slfn5 alleviates lipopolysaccharide-induced pneumonia by regulating Janus kinase/signal transduction and activator of transcription pathway.

In recent years, the incidence of pneumonia has been increasing, which is the main cause of death and morbidity of children and the elderly in the world. Slfn5 is implicated in multiple cancers, and Slfn5 promotes epithelial-mesenchymal transition and metastasis in lung cancer. However, the influences of Slfn5 in pneumonia have not yet been completely cleared. Herein, we aimed to explore the underlying effects and regulatory mechanisms of Slfn5 in lipopolysaccharide (LPS)-induced pneumonia in mice and A549 cells. Mice were intratracheally administered 5 mg/kg LPS to construct pneumonia model. In vitro, A549 cells were treated with 10 µg/mL LPS to construct cellular pneumonia model. Slfn5 expression was detected using immunohistochemistry and western blotting. Haematoxylin and eosin staining, TUNEL (terminal deoxynucleotidyl transferasemediated deoxyuridine triphosphate‑biotin nick end‑labelling), and western blotting were performed to assess pathological injury and inflammation. MTT [3(4,5‑dimethyl‑2‑thiazolyl)‑2,5‑diphenyl‑2‑H‑tetrazolium bromide], flow cytometry, and enzyme-linked immunosorbent assay analysis were performed to analyze cell viability, apoptosis, and inflammation. Gene set enrichment analysis was performed to explore the mechanism of Slfn5 in pneumonia. Slfn5 expression was upregulated in LPS-induced pneumonia in mice and A549 cells. In mice, knockdown of Slfn5 weakened LPS-induced lung injury and inflammation and decreased the expression of p-JAK2, p-JAK3, and p-STAT3. In LPS-stimulated A549 cells, downregulation of Slfn5 expression increased and Slfn5 overexpression decreased cell viability. Downregulation of Slfn5 expression decreased and Slfn5 overexpression increased cell apoptosis, inflammation and the expression of p-JAK2, p-JAK3, and p-STAT3. AG490, an inhibitor of the JAK/STAT pathway, reversed the damaging effects of Slfn5 overexpression. In the LPS-induced pneumonia model, Slfn5 knockdown alleviated LPS-induced lung injury by regulating the JAK/STAT pathway.

Morphological Preconditions of Metabolic Disorders in the Comorbid Course of Inflammatory Processes in the Lungs and Type 2 Diabetes Mellitus in Rats

Objective — to characterize ultrastructural changes in lung and liver cells associated with disturbances in energy metabolism during the comorbid course of inflammation in the lungs and type 2 diabetes mellitus (T2DM). Materials and methods. The study was conducted on adult Wistar rats, divided into four groups: 1) control; 2) rats with simulated inflammation by lipopolysaccharide (LPS) administration (0.5 mg/kg intraperitoneally); 3) rats with insulin resistance induced by a high-fat diet (58 % of total calorie intake from lipids) and LPS injection on the 24th day of the experiment; 4) rats with simulated T2DM by a high-fat diet, streptozotocin injection (25 mg/kg body weight) on the 14th day, and LPS injection on the 24th day of the experiment. The ultrastructure of lung and liver cells was evaluated by electron microscopy in tissue samples obtained from anesthetized animals three days after LPS administration. Results and discussion. In the simulation of inflammation induced by LPS-mediated cytokine mechanisms, inflam­matory symptoms were observed in the lungs, with alveolar type II cells showing mitochondrial dysfunc­tion, a large number of free and attached ribosomes, indicating disruptions in energy metabolism, and the development of compensatory-adaptive reactions (intensification of protein synthesis, reparative processes in mitochondria and their interaction with the endoplasmic reticulum). In the comorbid course of LPS-in­duced inflammation in the lungs and T2DM, enhanced inflammatory manifestations in the lungs were registered against the background of lipid infiltration, increased aero-hydrate barrier hydration, endothelial dysfunction and signs of mitochondrial dysfunction in alveolar type II cells. Compensatory protein synthesis increased, indicating the intensification of alteration processes, and worsening of energy and lipid metabolism. In the simulation of LPS-induced inflammation in the lungs with insulin resistance, pathological manifestations were less pronounced, and mitochondrial dysfunction was not observed, indicating the maintenance of energy metabolism under these conditions, with insulin resistance playing a partial role in the unfavourable course of comorbid pathology. In the liver, during the comorbid course of LPS-induced inflammation in the lungs and T2DM, increased steatosis, endothelial dysfunction, signs of mitochondrial dysfunction in hepatocytes, pronounced compensatory protein synthesis in bound ribosomes, and the formation of endoplasmic reticulum-associated membranes with mitochondria were detected. Conclusions. During the comorbid course of LPS-induced lung inflammation and T2DM, disruptions in energy metabolism intensify, mediated by respiratory and mitochondrial dysfunction, and compensatory protein synthesis and interaction of mitochondria with the endoplasmic reticulum are enhanced. The results suggest that the pathogenesis of comorbid inflammation in the lungs and T2DM or insulin resistance occurs through possible compensation of carbohydrate and energy metabolism disorders at the expense of worsening lipid metabolism and progression of obesity.

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

ObjectiveInflammation and oxidative stress contribute to the pathogenesis of acute lung injury (ALI), and subsequently result in rapid deterioration in health. Considering the indispensable role of bisdemethoxycurcumin (BDMC) in inflammation and oxidative stress, the present study aims to examine the effect of BDMC on sepsis-related ALI.MethodsC57BL/6 mice were administered with BDMC (100 mg/kg) or an equal volume of vehicle, and then injected with lipopolysaccharides (LPS) to induce ALI. We assessed the parameters of lung injury, inflammatory response and oxidative stress in lung tissues. Consistently, the macrophages with or without BDMC treatment were exposed to LPS to verify the effect of BDMC in vitro.ResultsBDMC suppressed LPS-induced lung injury, inflammation and oxidative stress in vivo and in vitro. Mechanistically, BDMC increased the phosphorylation of AMPKα in response to LPS stimulation, and AMPK inhibition with Compound C almost completely blunted the protective effect of BDMC in LPS-treated mice and macrophages. Moreover, we demonstrated that BDMC activated AMPKα via the cAMP/Epac pathway.ConclusionOur study identifies the protective effect of BDMC against LPS-induced ALI, and the underlying mechanism may be related to the activation of cAMP/Epac/AMPKα signaling pathway.

IRE1α/XBP-1 promotes β-catenin signaling activation of airway epithelium in lipopolysaccharide-induced acute lung injury

BackgroundAcute lung injury (ALI), along with the more severe condition--acute respiratory distress syndrome (ARDS), is a major cause of respiratory failure in critically ill patients with high morbidity and mortality. Inositol-requiring protein 1α (IRE1α)/X box protein-1 (XBP1) pathway was proved to regulate lipopolysaccharide (LPS)-induced lung injury and inflammation. Yet, its role on epithelial β-catenin in LPS-induced ALI remains to be elucidated. MethodsLPS-induced models were generated in mice (5 mg/kg) and Beas-2B cells (200 μg/mL). Two selective antagonists of IRE1α (4μ8c and STF-083010) were respectively given to LPS-exposed mice and cultured cells. ResultsUp-regulated expression of endoplasmic reticulum (ER) stress markers immunoglobulin-binding protein (BIP) and spliced X box protein-1(XBP-1s) was detected after LPS exposure. Besides, LPS also led to a down-regulated total β-catenin level in the lung and Beas-2B cells, with decreased membrane distribution as well as increased cytoplasmic and nuclear accumulation, paralleled by extensively up-regulated downstream targets of the Wnt/β-catenin signaling. Treatment with either 4μ8c or STF-083010 not only significantly attenuated LPS-induced lung injury and inflammation, but also recovered β-catenin expression in airway epithelia, preserving the adhesive function of β-catenin while blunting its signaling activity. ConclusionThese results illustrated that IRE1α/XBP1 pathway promoted the activation of airway epithelial β-catenin signaling in LPS-induced ALI.

Meteorin-like/Meteorin-β protects LPS-induced acute lung injury by activating SIRT1-P53-SLC7A11 mediated ferroptosis pathway

BackgroundFerroptosis plays an essential role in lipopolysaccharide (LPS)-induced acute lung injury (ALI). Meteorin-like/Meteorin-β (Metrnβ) is a protein secreted by skeletal muscle and adipose tissue and plays a role in cardiovascular diseases. However, its role in acute lung injury has not been elucidated.MethodsIn this study, we used an adenovirus (Ad) delivery system to overexpress or knockdown Metrnβ in lung tissue to examine the role of Metrnβ in LPS-induced acute lung injury.ResultsWe found that ferroptosis was increased during LPS-induced ALI. The expression of Metrnβ was reduced in ALI lung tissue. Overexpression of Metrnβ in lung tissue alleviated LPS-induced lung injury, inflammation, and ferroptosis. Moreover, Metrnβ knockout in lung tissue accelerated LPS-induced ALI, inflammation, and ferroptosis. We also cultured MLE-12 cells and transfected the cells with Ad-Metrnβ or Metrnβ siRNA. Metrnβ overexpression ameliorated LPS-induced MLE cell death, inflammation and ferroptosis, while Metrnβ knockdown aggregated cell survival and decreased inflammation and ferroptosis. Moreover, we found that Metrnβ enhanced ferroptosis-related Gpx4 expression and reduced ferroportin and ferritin levels. Furthermore, we found that Metrnβ positively regulated SIRT1 transcription thus inhibited P53, increased SLC7A11 expression. When we used the ferroptosis inhibitor ferrostatin-1, the deteriorating effects of Metrnβ knockout were abolished in ALI mice. Moreover, SIRT1 knockout also abolished the protective effects of Metrnβ overexpression in vivo.ConclusionsTaken together, Metrnβ could protect LPS-induced ALI by activating SIRT1-P53- SLC7A11 mediated ferroptosis inhibition.

Inhalation of panaxadiol alleviates lung inflammation via inhibiting TNFA/TNFAR and IL7/IL7R signaling between macrophages and epithelial cells

BackgroundLung inflammation occurs in many lung diseases, but has limited effective therapeutics. Ginseng and its derivatives have anti-inflammatory effects, but their unstable physicochemical and metabolic properties hinder their application in the treatment. Panaxadiol (PD) is a stable saponin among ginsenosides. Inhalation administration may solve these issues, and the specific mechanism of action needs to be studied. MethodsA mouse model of lung inflammation induced by lipopolysaccharide (LPS), an in vitro macrophage inflammation model, and a coculture model of epithelial cells and macrophages were used to study the effects and mechanisms of inhalation delivery of PD. Pathology and molecular assessments were used to evaluate efficacy. Transcriptome sequencing was used to screen the mechanism and target. Finally, the efficacy and mechanism were verified in a human BALF cell model. ResultsInhaled PD reduced LPS-induced lung inflammation in mice in a dose-dependent manner, including inflammatory cell infiltration, lung tissue pathology, and inflammatory factor expression. Meanwhile, the dose of inhalation was much lower than that of intragastric administration under the same therapeutic effect, which may be related to its higher bioavailability and superior pharmacokinetic parameters. Using transcriptome analysis and verification by a coculture model of macrophage and epithelial cells, we found that PD may act by inhibiting TNFA/TNFAR and IL7/IL7R signaling to reduce macrophage inflammatory factor-induced epithelial apoptosis and promote proliferation. ConclusionPD inhalation alleviates lung inflammation and pathology by inhibiting TNFA/TNFAR and IL7/IL7R signaling between macrophages and epithelial cells. PD may be a novel drug for the clinical treatment of lung inflammation.

Costunolide attenuates LPS-induced inflammation and lung injury through inhibiting IKK/NF-κB signaling.

Inflammation is an important pathological process of many acute and chronic diseases, such as sepsis, arthritis, and cancer. Many factors can lead to an inflammatory state of the body, among which bacterial infection plays an important role. Bacterial infection often leads to sepsis, acute lung injury (ALI), or its more serious form of acute respiratory distress syndrome, which are the main fatal diseases in intensive care units. Costunolide has been reported to possess excellent anti-inflammatory activity; however, whether it can affect inflammation induced by gram-negative bacterial is still unclear. Lipopolysaccharide (LPS) stimulated mouse peritoneal macrophages (MPMs) to release proinflammatory cytokines was used as the cell model. The mouse model of sepsis and ALI was built through injecting intravenously and intratracheally of LPS. In the present study, costunolide inhibited LPS-induced inflammatory response through IKK/NF-κB signaling pathway in macrophages. In vivo, costunolide attenuated LPS-induced septic death in mice. Meanwhile, costunolide treatment alleviated LPS-induced lung injury and inflammation via inhibiting the infiltration of inflammatory cells and the expression of inflammatory cytokines. Taken together, these results demonstrated that costunolide could attenuate gram-negative bacterial induced inflammation and diseases and might be a potential candidate for the treatment of inflammatory diseases.

N-3 Polyunsaturated Fatty Acids Modulate LPS-Induced ARDS and the Lung-Brain Axis of Communication in Wild-Type versus Fat-1 Mice Genetically Modified for Leukotriene B4 Receptor 1 or Chemerin Receptor 23 Knockout.

Specialized pro-resolving mediators (SPMs) and especially Resolvin E1 (RvE1) can actively terminate inflammation and promote healing during lung diseases such as acute respiratory distress syndrome (ARDS). Although ARDS primarily affects the lung, many ARDS patients also develop neurocognitive impairments. To investigate the connection between the lung and brain during ARDS and the therapeutic potential of SPMs and its derivatives, fat-1 mice were crossbred with RvE1 receptor knockout mice. ARDS was induced in these mice by intratracheal application of lipopolysaccharide (LPS, 10 µg). Mice were sacrificed at 0 h, 4 h, 24 h, 72 h, and 120 h post inflammation, and effects on the lung, liver, and brain were assessed by RT-PCR, multiplex, immunohistochemistry, Western blot, and LC-MS/MS. Protein and mRNA analyses of the lung, liver, and hypothalamus revealed LPS-induced lung inflammation increased inflammatory signaling in the hypothalamus despite low signaling in the periphery. Neutrophil recruitment in different brain structures was determined by immunohistochemical staining. Overall, we showed that immune cell trafficking to the brain contributed to immune-to-brain communication during ARDS rather than cytokines. Deficiency in RvE1 receptors and enhanced omega-3 polyunsaturated fatty acid levels (fat-1 mice) affect lung-brain interaction during ARDS by altering profiles of several inflammatory and lipid mediators and glial activity markers.

LC-QToF chemical profiling of Euphorbia grantii Oliv. and its potential to inhibit LPS-induced lung inflammation in rats via the NF-κB, CY450P2E1, and P38 MAPK14 pathways

Acute lung injury (ALI) is a life-threatening syndrome that causes high morbidity and mortality worldwide. The aerial parts of Euphorbia grantii Oliv. were extracted with methanol to give a total methanolic extract (TME), which was further fractionated into dichloromethane (DCMF) and the remaining mother liquor (MLF) fractions. Biological guided anti-inflammatory assays in vitro revealed that the DCMF showed the highest activity (IC50 6.9 ± 0.2 μg/mL and 0.29 ± 0.01 μg/mL) compared to. celecoxib (IC50 of 88.0 ± 1 μg/mL and 0.30 ± 0.01 μg/mL) on COX-1 and COX-2, respectively. Additionally, anti-LOX activity was IC50 = 24.0 ± 2.5 μg/mL vs. zileuton with IC50 of 40.0 ± 0.5 μg/mL. LC-DAD-QToF analysis of TME and the active DCMF resulted in the tentative identification and characterization of 56 phytochemical compounds, where the diterpenes were the dominated metabolites. An LPS-induced inflammatory model of ALI (10 mg/kg i.p) was used to assess the anti-inflammatory potential of DCMF in vivo at dose of 200 mg/kg and 300 mg/kg compared to dexamethasone (5 mg/kg i.p). Our treatments significantly reduced the pro-inflammatory cytokines (TNF-α, IL-1, IL-6, and MPO), increased the activity of antioxidant enzymes (SOD, CAT, and GSH), decreased the activity of oxidative stress enzyme (MDA), and reduced the expression of inflammatory genes (p38.MAPK14 and CY450P2E1). The western blotting of NF-κB p65 in lung tissues was inhibited after orally administration of the DCMF. Histopathological study of the lung tissues, scoring, and immunohistochemistry of transforming growth factor-beta 1 (TGF-β1) were also assessed. In both dose regimens, DCMF of E. grantii prevented further lung damage and reduced the side effects of LPS on acute lung tissue injury.

Platycodonis Radix Alleviates LPS-Induced Lung Inflammation through Modulation of TRPA1 Channels

Platycodonis Radix (PR), a widely consumed herbal food, and its bioactive constituents, platycodins, have therapeutic potential for lung inflammation. Transient Receptor Potential Ankyrin 1 (TRPA1), which is essential for the control of inflammation, may be involved in the development of inflammation in the lungs. The aim of this study was to determine the TRPA1-targeted effects of PR against pulmonary inflammation and to investigate the affinity of PR constituents for TRPA1 and their potential mechanisms of action. Using a C57BL/6J mouse lipopolysaccharides (LPS) intratracheal instillation pneumonia model and advanced analytical techniques (UPLC-Q-TOF-MS/MS, molecular docking, immuno-fluorescence), five platycodins were isolated from PR, and the interaction between these platycodins and hTRPA1 was verified. Additionally, we analyzed the impact of platycodins on LPS-induced TRPA1 expression and calcium influx in BEAS-2B cells. The results indicated that PR treatment significantly reduced the severity of LPS-triggered inflammation in the mouse model. Interestingly, there was a mild increase in the expression of TRPA1 caused by PR in healthy mice. Among five isolated platycodins identified in the PR extract, Platycodin D3 (PD3) showed the highest affinity for hTRPA1. The interaction between platycodins and TRPA1 was verified through molecular docking methods, highlighting the significance of the S5–S6 pore-forming loop in TRPA1 and the unique structural attributes of platycodins. Furthermore, PD3 significantly reduced LPS-induced TRPA1 expression and calcium ion influx in BEAS-2B cells, substantiating its own role as an effective TRPA1 modulator. In conclusion, PR and platycodins, especially PD3, show promise as potential lung inflammation therapeutics. Further research should explore the precise mechanisms by which platycodins modulate TRPA1 and their broader therapeutic potential.

Rgl-exomiR-7972, a novel plant exosomal microRNA derived from fresh Rehmanniae Radix, ameliorated lipopolysaccharide-induced acute lung injury and gut dysbiosis

Plant-derived exosome-like nanoparticles (ELNs) have been proposed as a novel therapeutic tool for preventing human diseases. However, the number of well-verified plant ELNs remains limited. In this study, the microRNAs in ELNs derived from fresh Rehmanniae Radix, a well-known traditional Chinese herb for treating inflammatory and metabolic diseases, were determined by using microRNA sequencing to investigate the active components in the ELNs and the protection against lipopolysaccharide (LPS)-induced acute lung inflammation in vivo and in vitro. The results showed that rgl-miR-7972 (miR-7972) was the main ingredient in ELNs. It exerted stronger protective activities against LPS-induced acute lung inflammation than catalpol and acteoside, which are two well-known chemical markers in this herb. Moreover, miR-7972 decreased the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), reactive oxygen species (ROS) and nitric oxide (NO) in LPS-exposed RAW264.7 cells, thereby facilitating M2 macrophage polarization. Mechanically, miR-7972 downregulated the expression of G protein-coupled receptor 161 (GPR161), activating the Hedgehog pathway, and inhibited the biofilm form of Escherichia coli via targeting virulence gene sxt2. Therefore, miR-7972 derived from fresh R. Radix alleviated LPS-induced lung inflammation by targeting the GPR161-mediated Hedgehog pathway, recovering gut microbiota dysbiosis. It also provided a new direction for gaining novel bioactivity nucleic acid drugs and broadening the knowledge on cross-kingdom physiological regulation through miRNAs.