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Background and Purpose: Toll‐like receptors 4 (TLR4) and TLR7/TLR8 play an important role in mediating the inflammatory effects of bacterial and viral pathogens. Interleukin‐1 receptor‐associated kinase 4 (IRAK4) is an important regulator of signalling by toll‐like receptor (TLR) and hence is a potential therapeutic target in diseases characterized by increased lung inflammatory signalling. Experimental Approach: We used an established murine model of acute lung inflammation, and studied human lung tissue ex vivo, to investigate the effects of inhibiting IRAK4 on lung inflammatory pathways. Key Results: We show that TLR4 stimulation produces an inflammatory response characterized by neutrophil influx and tumour necrosis factor‐α (TNF‐α) production in murine lungs and that these responses are markedly reduced in IRAK4 kinase‐dead mice. In addition, we characterize a novel selective IRAK4 inhibitor, BI1543673, and show that this compound can reduce lipopolysaccharide (LPS)‐induced airway inflammation in wild‐type mice. Additionally, BI1543673 reduced inflammatory responses to both TLR4 and TLR7/8 stimulation in human lung tissue studied ex vivo. Conclusion and Implications: These data demonstrate a key role for IRAK4 signalling in lung inflammation and suggest that IRAK4 inhibition has potential utility to treat lung diseases characterized by inflammatory responses driven through TLR4 and TLR7/8. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) is the most common and severe form of pulmonary fibrosis, characterized by scar formation in the lung interstitium. Transforming growth factor beta (TGF-b) is known as a key mediator in the fibrotic process, acting on fibroblasts and mediating their proliferation and differentiation into myofibroblasts. Although the immune system is not considered responsible for the initiation of IPF, markers of tolerogenic immunity define the pro-fibrotic microenvironment in the lungs. In homeostatic conditions, regulatory T cells (Tregs) constitute the main lymphoid population responsible for maintaining peripheral tolerance. Similar to Tregs, regulatory B cells (Bregs) represent a recently described subset of B lymphocytes with immunosuppressive functions. In the context of IPF, numerous studies have suggested a role for Tregs in enhancing fibrosis, mainly via the secretion of TGF-b. In humans, most studies show increased percentages of Tregs associated with the severity of IPF, although their exact role remains unclear. In mice, the most commonly used model involves triggering acute lung inflammation with bleomycin, leading to a subsequent fibrotic process. Consequently, data are still conflicting, as Tregs may play a protective role during the inflammatory phase and a deleterious role during the fibrotic phase. Bregs have been less studied in the context of IPF, but their role appears to be protective in experimental models of lung fibrosis. This review presents the latest updates on studies exploring the implication of regulatory lymphoid cells in IPF and compares the different approaches to better understand the origins of conflicting findings. [ABSTRACT FROM AUTHOR]

Purpose: Amniotic fluid stem cell extracellular vesicles (AFSC-EVs) hold regenerative potential to treat hypoplastic lungs secondary to congenital diaphragmatic hernia (CDH). This study aims to investigate sex-specific differences in pulmonary hypoplasia severity and responses to AFSC-EV administration in an experimental CDH mouse model. Methods: C57BL/6J dams were fed with nitrofen + bisdiamine (left-sided CDH) or olive oil only (control) at embryonic day (E) 8.5. Lungs were dissected (E18.5), grown ex vivo and treated with medium ± AFSC-EVs that were collected via ultracentrifugation and characterized (nanoparticle tracking analysis, electron microscopy, Western blotting). Pulmonary hypoplasia was assessed via mean linear intercept (MLI). Gene and protein expression changes (Cd31, Enos, Il1b, TNFa) were measured via RT-qPCR and immunofluorescence. Pups were genotyped for Sry. Results: Experimental CDH showed a male predominance without sex differences for pulmonary hypoplasia severity, fetal lung vascularization, and inflammation. AFSC-EV administration led to improved lung growth (decreased MLI), improved fetal lung vascularization (increased Cd31 and Enos), and decreased fetal lung inflammation (Il1b, TNFa). There was no sex-specific response to AFSC-EV administration. Conclusion: This study shows sex-independent impaired lung growth, vascularization and fetal lung inflammation in a CDH mouse model. Antenatal administration of AFSC-EVs reverses aspects of pulmonary hypoplasia secondary to CDH independent of the biological sex. [ABSTRACT FROM AUTHOR]

Background Aim Methods Results Conclusions Air pollutants, such as diesel exhaust particles (DEPs), induce respiratory disease exacerbation with neutrophilic infiltration. Progranulin (PGRN), an epithelial cell and macrophage‐derived secretory protein, is associated with neutrophilic inflammation. PGRN is digested into various derivatives at inflammatory sites and is involved in several inflammatory processes. PGRN and its derivatives likely regulate responses to DEP exposure in allergic airway inflammation.To investigate the role of PGRN and its derivatives in the regulation of responses to DEP exposure in allergic airway inflammation.A murine model of allergic airway inflammation was generated in PGRN‐deficient mice, and they were simultaneously exposed to DEP followed by intranasal administration of full‐length recombinant PGRN (PGRN‐FL) and a PGRN‐derived fragment (FBAC). Inflammatory status was evaluated by bronchoalveolar lavage fluid and histopathologic analyses. Human bronchial epithelial cells were stimulated with DEPs and house dust mites (HDMs), and the effect of FBAC treatment was evaluated by assessing various intracellular signaling molecules, autophagy markers, inflammatory cytokines, and intracellular oxidative stress.DEP exposure exaggerated neutrophilic inflammation, enhanced IL‐6 and CXCL15 secretions, and increased oxidative stress in the murine model; this effect was greater in PGRN‐deficient mice than in wild‐type mice. The DEP‐exposed mice with PGRN‐FL treatment revealed no change in neutrophil infiltration and higher oxidative stress status in the lungs. On the contrary, FBAC administration inhibited neutrophilic infiltration and reduced oxidative stress. In human bronchial epithelial cells, DEP and HDM exposure increased intracellular oxidative stress and IL‐6 and IL‐8 secretion. Decreased nuclear factor erythroid 2‐related factor 2 (Nrf2) expression and increased phosphor‐p62 and LC3B expression were also observed. FBAC treatment attenuated oxidative stress from DEP and HDM exposure.FBAC reduced neutrophilic inflammation exaggerated by DEP exposure in a mouse model of allergic airway inflammation by reducing oxidative stress. PGRN and PGRN‐derived proteins may be novel therapeutic agents in attenuating asthma exacerbation induced by air pollutant exposure. [ABSTRACT FROM AUTHOR]

Background Objectives Animals Methods Results Conclusions and Clinical Importance Respirable mineral particles can induce lower airway inflammation, but the role they play in asthma of horses is unknown.Respirable mineral particles, particularly respirable silica, are an overlooked determinant of chronic lung inflammation (asthma) in horses.Twenty‐three horses from an equine hospital population: 11 moderately affected (MEA), 7 severely asthmatic (SEA), and 5 control horses free from respiratory clinical signs.Prospective observational study. The quantity and quality of mineral particles found in bronchoalveolar lavage fluid (BALF) were characterized, with particular attention to silica content. Polarized light microscopy performed on cytospin slides identified intracellular birefringent particles as silica. Spectrometry‐based analysis performed on whole BALF determined total mineral and silica percentage and concentration. Group‐related differences in BALF mineral and silica load were investigated as well as associations with BALF cytology.Intracellular birefringent particles were increased in SEA vs MEA (median [interquartile range, IQR]), 12 [7] vs 4 [5] particles/30 high power fields [hpf], respectively; P = .01) and vs controls (4 [2] particles/30 hpf; P = .02). Total mineral concentration in BALF was similar between the groups studied, whereas silica concentration and percentage were increased in SEA vs MEA (1758 [887] particles/mL and 20 [10]% vs 867 [662] particles/mL and 8 [6]%; P = .009 and P = .001) and control group (355 [330] particles/mL and 6 [3]%; P = .0003 and P = .002). Silica load in BALF was associated with BALF neutrophilia in MEA and SEA.Respirable silica is associated with neutrophilic lower airway inflammation in horses and might contribute to asthma development. [ABSTRACT FROM AUTHOR]

Type III interferons (λ1, λ2, and λ3) are potent antiviral cytokines in the lung. However, their roles in nonviral lung injuries are less well understood. This study investigates the activation of type III interferon signaling in three distinct models of lung injuries caused by diverse stimuli: the bacterial pathogen Pseudomonas aeruginosa, bacterial endotoxin LPS, and the chemotherapeutic agent bleomycin. Our data show that, despite inducing a potent inflammatory response, Pseudomonas and LPS did not increase IFNλ secretion. In contrast, bleomycin instillation increased secretion of IFNλ in the airways at both early and late time points. Consistent with limited secretion, type III interferon signaling had a minimal role in the host response to both Pseudomonas and LPS, as measured by pathogen burden, inflammatory response, and lung injury. Conversely, a deficiency in type III interferon signaling led to increased inflammatory signaling and elevated acute lung injury in the bleomycin model on day 3. This elevated early injury resulted in impaired recovery in IFNLR1 knockout mice, as evidenced by their recovery from bleomycin‐induced weight loss. Taken together, these data suggest a context‐specific activation of type III interferon signaling, where it plays an anti‐inflammatory role in the lung. [ABSTRACT FROM AUTHOR]

Gut microbiota is an intricate microbial community containing bacteria, fungi, viruses, archaea, and protozoa, and each of them contributes to diverse aspects of host health. Nevertheless, the influence of interaction among gut microbiota on host health remains uncovered. Here, we showed that the interaction between intestinal fungi and bacteria shaped lung inflammation during infection. Specifically, antifungal drug‐induced dysbiosis of gut mycobiota enhanced lung inflammation during infection. Dysbiosis of gut mycobiota led to gut Escherichia coli (E. coli) overgrowth and translocation to the lung during infection, which induced lung accumulation of the CD45+F4/80+Ly6G−Ly6C−CD11b+CD11c+ macrophages. Clearance of macrophages or deletion of TLR4 (Toll‐like receptor 4, recognition of LPS) rather than Dectin‐1 (recognition of beta‐1,3/1,6 glucans on fungi) blocked the antifungal drug‐induced aggravation of lung inflammation during infection. These findings suggest that the interaction between intestinal mycobiota and commensal bacteria affects host health through the gut–lung axis, offering a potential therapeutic target for ameliorating lung inflammation during infection. Highlights: Antifungal drug‐induced dysbiosis of gut mycobiota aggravates lung inflammation during infection.Dysbiosis of intestinal mycobiota results in gut Escherichia coli overgrowth and translocation to the lung during infection.E. coli induces lung accumulation of the CD45+F4/80+Ly6G−Ly6C−CD11b+CD11c+ macrophages.Clearance of macrophages or deletion of TLR4 blocks the antifungal drug‐induced aggravation of lung inflammation during infection. [ABSTRACT FROM AUTHOR]

Regnase-1 is an RNase that plays a critical role in negatively regulating immune responses by destabilizing inflammatory messenger RNAs (mRNAs). Dysfunction of Regnase-1 can be a major cause of various inflammatory diseases with tissue injury and immune cell infiltration into organs. This study focuses on the role of the RNase activity of Regnase-1 in developing inflammatory diseases. We have constructed mice with a single point mutation at the catalytic center of the Regnase-1 RNase domain, which lacks endonuclease activity. D141N mutant mice demonstrated systemic inflammation, immune cell infiltration into various organs, and progressive development of lung granuloma. CD4+ T cells, mainly affected by this mutation, upregulated the mTORC1 pathway and facilitated the autoimmune trait in the D141N mutation. Moreover, serine/threonine kinase Pim2 contributed to lung inflammation in this mutation. Inhibition of Pim2 kinase activity ameliorated granulomatous inflammation, immune cell infiltration, and proliferation in the lungs. Additionally, Pim2 inhibition reduced the expression of adhesion molecules on CD4+ T cells, suggesting a role for Pim2 in facilitating leukocyte adhesion and migration to inflamed tissues. Our findings provide new insights into the role of Regnase-1 RNase activity in controlling immune functions and underscore the therapeutic relevance of targeting Pim2 to modulate abnormal immune responses. [ABSTRACT FROM AUTHOR]

Inflammation is an essential factor in pulmonary complications of diabetes. Bone marrow (BM)-derived C-kit+ cells have immunomodulatory properties and their transplantation is suggested as a promising strategy for ameliorating diabetes complications. This study evaluated the effect of BM-derived C-kit+ cells on the inflammation signaling pathway in lung tissue of type 2 diabetic male rats. Ten rats were used to extract C-kit cells, and 48 male Wistar rats weighing 180 ± 20 g were randomly divided into four equal groups: (1) Control (Cont), (2) Diabetic (D), (3) Diabetic + C-kit+ cells (D + C-kit pos) intravenously injected 50-µl phosphate buffer saline (PBS) containing 300,000 C-kit+ cells, and (4) Diabetic + C-kit− cells (D + C-kit neg), intravenously injected C-kit− cells. Diabetes induction increased IL-33, ST-2, CD127, and IL-2 levels and decreased IL-10. C-kit+ cell therapy significantly decreased IL-33 and CD127 and increased IL-10. In addition, lung histopathological changes significantly improved in the C-kit+ group compared to the diabetic group. These findings suggest that C-kit+ cells may have a potential therapeutic role in mitigating diabetes-induced respiratory complications via ameliorating the inflammation and histopathological changes in lung tissue. [ABSTRACT FROM AUTHOR]

Tertiary lymphoid structures (TLS) resemble follicles of secondary lymphoid organs and develop in nonlymphoid tissues during inflammation and cancer. Which cell types and signals drive the development of TLS is largely unknown. To investigate early events of TLS development in the lungs, we repeatedly instilled p(I:C) plus ovalbumin (Ova) intranasally. This induced TLS ranging from lymphocytic aggregates to organized and functional structures containing germinal centers. We found that TLS development is independent of FAP+ fibroblasts, alveolar macrophages, or CCL19 but crucially depends on type I interferon (IFN‐I). Mechanistically, IFN‐I initiates two synergistic pathways that culminate in the development of TLS. On the one hand, IFN‐I induces lymphotoxin (LT)α in lymphoid cells, which stimulate stromal cells to produce the B‐cell‐attracting chemokine CXCL13 through LTβR‐signaling. On the other hand, IFN‐I is sensed by stromal cells that produce the T‐cell‐attracting chemokines CXCL9, CXCL10 as well as CCL19 and CCL21 independently of LTβR. Consequently, B‐cell aggregates develop within a week, whereas follicular dendritic cells and germinal centers appear after 3 weeks. Thus, sustained production of IFN‐I together with an antigen is essential for the induction of functional TLS in the lungs. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS), a severe form of acute lung injury (ALI), is the major cause of intensive care unit death worldwide. ALI/ARDS is a common condition characterized by a storm of potent inflammatory cytokines. Lung delivery of glucocorticoids (GCs) by inhalation is a potential approach for ALI treatment and ARDS prevention; however, its efficacy is limited by the rapid clearance of GCs in lungs. In this study, we developed surface-modified poly(lactic acid)-hyperbranched polyglycerol nanoparticles (BNPs) with bioadhesive properties for local delivery to the epidermis of lung tissues, which exhibited prolonged release profile of payloads following intratracheal spraying administration. Compared with that of non-adhesive nanoparticles (NNPs), BNPs showed significantly enhanced adhesion and prolonged retention within lung tissues in vivo. Lipopolysaccharide (LPS)-induced ALI mice treated with betamethasone dipropionate (BD)-loaded BNPs showed significantly fewer lung histological alterations and less lung inflammation than those administered free BD or BD-loaded NNPs, indicating the enhanced therapeutic efficacy of BD/BNPs in ALI. In contrast, the features of ARDS were observed in the animal models without any treatments. Our findings demonstrated that pulmonary delivery of BNPs can maintain their same surface structures and continuously form covalent connections with the contacted tissues, emphasizing their potential to improve the therapeutic efficacy in ALI and prevent from ARDS. [ABSTRACT FROM AUTHOR]

Background and Objectives: The aging process has always been associated with a higher susceptibility to chronic inflammatory lung diseases. Several studies have demonstrated the gut microbiome's influence on the lungs through cross-talk or the gut–lungs axis maintaining nutrient-rich microenvironments. Taiwan djulis (Chenopodium formosanum Koidz.) provides antioxidant and anti-inflammatory characteristics that could modulate the gut microbiome. This could induce the gut–lung axis through microbial cross-talk, thus favoring the modulation of lung inflammation. Materials and Methods: Here, we investigate the immune mRNA expression in the spleen, fecal microbiome composition, and hyperplasia of the bronchial epithelium in aged 2-year-old BALB/c mice after 60 days of supplementation of djulis. Results: The pro-inflammatory cytokines IFN-γ, TNF-α, and IL-1β, T; cells CD4 and CD8; and TLRs TLR3, TLR4, TLR5, TLR7, TLR8, and TLR9 were reduced in their mRNA expression levels, while the anti-inflammatory cytokines IL-2, IL-4, and IL-10 were highly expressed in the C. formosanum-treated group. Interestingly, the fecal microbiome composition analysis indicated higher diversity in the C. formosanum-treated group and the presence of butyrate-producing bacteria that are beneficial in the gut microbiome. The histopathology showed reduced hyperplasia of the bronchial epithelium based on the degree of lesions. Conclusions: Our findings suggest that Taiwan djulis can modulate the gut microbiome, leading to microbial cross-talk; reducing the mRNA expression of pro-inflammatory cytokines, T cells, and TLRs; and increasing anti-inflammatory cytokines in the spleen, as cytokines migrate in the lungs, preventing lung inflammation damage in aged mice or the gut–lung axis. Thus, Taiwan djulis could be considered a beneficial dietary component for the older adult population. The major limitation includes a lack of protein validation of cytokines and TLRs and quantification of the T cell population in the spleen as a marker of the gut–lung axis. [ABSTRACT FROM AUTHOR]

Hui Xu,1,2 Xin Li,1 Kai Liu,1 Ping Huang,1 Xiao-Ju Liu1,2 1The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, People’s Republic of China; 2The First Hospital of Lanzhou University, Lanzhou, Gansu, People’s Republic of ChinaCorrespondence: Xiao-Ju Liu, Email liuxiaoju835@126.comBackground: Airway epithelial cells (AECs) and alveolar macrophages are involved in airway inflammation. The direct effects of atmospheric fine-particulate-matter (PM2.5) on airway cells, such as AECs and alveolar macrophages, have been widely investigated, but the effect of cell-cell interaction on inflammatory response remains unclear. Exosomes play a crucial role in intercellular communication. However, the cellular interaction of exosomes in PM2.5-induced airway inflammation is unclear.Methods: The PM2.5-induced human bronchial epithelial (BEAS-2B) cells and phorbol 12-myristate 13-acetate-induced macrophages (M&phis;) were co-cultured and then the expression of IL-6, IL-1β, TNF-α and miRNA-155-5p were detected. Exosomes from PM2.5-exposed BEAS-2B cells were then co-cultured with M&phis; to detect the expression of miR-155-5p and inflammatory cytokines, as well as cytokine signaling inhibitor-1 (SOCS1)/NFκB, and to detect the effect of the exosome inhibitor GW4869.Results: After the co-culture of PM2.5-induced BEAS-2B cells and M&phis;, the expression of M&phis;-derived IL-6, IL-1β, and TNF-α, as well as miRNA-155-5p were upregulated. The expression of miRNA-155-5p was upregulated in BEAS-2B and BEAS-2B cell-derived exosomes after exposure to PM2.5. Furthermore, co-culturing exosomes derived from PM2.5-exposed BEAS-2B cells with M&phis;, upregulated miR-155-5p and inflammatory cytokines, decreased cytokine signaling inhibitor-1 (SOCS1) expression, and activated NF-κB. In addition, adding exosome inhibitor GW4869 to PM2.5-interfered BEAS-2B cells co-culture with M&phis; downregulated miRNA-155-5p expression, inhibited NF-κB, and reduced the levels of inflammatory factors.Conclusion: PM2.5 promotes M&phis; inflammation by upregulating miRNA-155-5P in exosomes obtained from BEAS-2B cells through miR-155-5P/SOCS1/NF-κB pathway. Exosomal miRNAs mediate cellular communication between BEAS-2B cells and M&phis;, which may be a new mechanism of PM2.5-stimulated pulmonary inflammatory response. Keywords: PM2.5, exosome, microRNA, lung inflammation

Haidong He,1 Shuihua Sun,2 Weihua Xu,1 Mingwan Zhang3 1Department of Pulmonary and Critical Care Medicine, Tongde Hospital of Zhejiang Province, Hangzhou City, Zhejiang Province, People’s Republic of China; 2Department of Medical Oncology, Tongde Hospital of Zhejiang Province, Hangzhou City, Zhejiang Province, People’s Republic of China; 3Department of Pharmacy, Tongde Hospital of Zhejiang Province, Hangzhou City, Zhejiang Province, People’s Republic of ChinaCorrespondence: Haidong He, Department of Pulmonary and Critical Care Medicine, Tongde Hospital of Zhejiang Province, 234 Gucui Road, Cuiyuan Street, Xihu District, Hangzhou City, Zhejiang Province, 310012, People’s Republic of China, Tel +86-571-89972427, Email hhd0901190040@163.comPurpose: Sangbaipi decoction (SBPD), a traditional Chinese medicine (TCM) prescription, has been widely used to treat acute exacerbation of chronic obstructive pulmonary disease (AECOPD), while the underlying pharmacological mechanism remains unclear due to the complexity of composition.Methods: A TCM-active ingredient-drug target network of SBPD was constructed utilizing the TCM-Systems-Pharmacology database. AECOPD-relevant proteins were gathered from Gene Cards and the Online-Mendelian-Inheritance-in-Man database. Protein–protein interaction, GO and KEGG enrichment analyses of the targets from the intersection of SBPD and AECOPD targets were performed to identify the core signaling pathway, followed by molecular docking verification of its interaction with active ingredients. The network pharmacology results were checked using in-vivo experiments. To induce AECOPD, rats were exposure to combined tobacco smoke and lipopolysaccharide (LPS). Then rats underwent gavage with stigmasterol (SM) after successful modeling. The involvement of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling was investigated using its inhibitor, LY294002. Lung function and histopathology were examined. The levels of inflammatory cytokines in the lung and serum were assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot and/or Enzyme-linked immunosorbent assay (ELISA).Results: SM was recognized as an active ingredient of SBPD and stably bound to Akt1. SM improved lung function and histological abnormalities, concomitant with suppressed PI3K/Akt signaling, downregulated lung and serum Interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) levels and serum transforming growth factor-β (TGF-β) levels and upregulated lung and serum Interleukin 10 (IL-10) levels in AECOPD rats. In AECOPD rats, LY294002 restored lung function, and it also improved lung histological abnormalities and inflammation, which was found to be potentiated by SM.Conclusion: SM targets PI3K/Akt signaling to reduce lung injury and inflammation in AECOPD rats.Keywords: sangbaipi decoction, stigmasterol, acute exacerbation of chronic obstructive pulmonary disease, PI3K/Akt signaling, lung inflammation

Exposure to storage mite (SM) and house dust mite (HDM) allergens is a risk factor for sensitization and asthma development; however, the related immune responses and their pathology have not been fully investigated. The HDMs Dermatophagoides farinae and Dermatophagoides pteronyssinus and SM Tyrophagus putrescentiae are potent allergens that induce asthma. Most SM-related studies have focused on the allergic reactions of individuals by measuring their immunoglobulin (Ig)E expression. Considering the limited research on this topic, the present study aims to investigate the differences in the immune responses induced by HDMs and SMs and histologically analyze lung tissues in a mouse asthma model to understand the differential effects of HDM and SM. The results revealed that all mite species induced airway inflammation. Mice challenged with T. putrescentiae had the highest airway resistance and total cell, eosinophil, and neutrophil counts in the bronchoalveolar lavage fluid (BALF). The SM-sensitized groups showed more severe lesions and mucus hypersecretions than the HDM-sensitized groups. Although the degree of HDM and SM exposure was the same, the damage to the respiratory lung tissue was more severe in SM-exposed mice, which resulted in excessive mucin secretion and increased fibrosis. Furthermore, these findings suggest that SM sensitization induces a more significant hypersensitivity response in mucosal immunity than HDM sensitization in asthma models. [ABSTRACT FROM AUTHOR]

Introduction: Exposure to environmental pollutants such as diesel exhaust particles (DEP) increases the risk of respiratory disease exacerbation. However, the possible effects of these particles on the general population remain poorly understood. The present study aimed to assess the immunomodulatory and inflammatory effects of the inhalation of DEP in a model of healthy mice undergoing short-, mid- and long-term exposure. Materials and Methods: BALB/c ByJ mice were randomly divided into five experimental groups. The control group received three intranasal instillations of saline over 8 days while the other four groups received intranasal instillations of 150 µg of DEP 3 days per week for 8, 17, 26, and 53 days. Lung function assessment and flow cytometry were performed. Results: In lung tissue, intranasal exposure to DEP decreased total monocytes (p < 0.015 in all groups). At 26 days, a reduction in inflammatory monocytes and an increase in resident monocytes were observed, p = 0.001 and 0.0001, respectively. Eosinophils and neutrophils decreased at 26 days (p = 0.017 and p = 0.041, respectively). The intranasal challenges of DEP increased the total population of dendritic cells (DC) at 26 and 53 days (p = 0.017 and p = 0.022, respectively) and decreased the total and alveolar populations of macrophages (p < 0.003 for all groups compared to control), while interstitial macrophage populations increased over the time period (p = 0.0001 for all groups compared to control). Conclusions: Continuous DEP exposure triggers immune mechanisms that predispose healthy individuals to a pro-inflammatory and hyper-reactive microenvironment. This mouse model provides evidence of the capacity of DEP to increase DC, interstitial macrophages, and resident monocytes. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanoparticles (TiO2NPs) are used in products that are applied to the human body, such as cosmetics and food, but their biocompatibility remains controversial. Pycnogenol (PYC), a natural extract of pine bark, exerts anti-inflammatory and antioxidant effects. In this study, we investigated whether PYC effectively alleviates pulmonary toxicity induced by airway exposure to TiO2NPs, and the beneficial effects of PYC were explained through the analysis of changes to the mechanism of cytotoxicity. TiO2NPs induced pulmonary inflammation and mucus production, increased the levels of malondialdehyde, and upregulated thioredoxin-interacting protein (TXNIP) and cleaved-caspase 3 (Cas3) in the lungs of mice. However, PYC treatment reduced the levels of all toxicity markers of TiO2NPs and restored glutathione levels. These antioxidant and anti-inflammatory effects of PYC were also demonstrated in TiO2NP-exposed human airway epithelial cells by increasing the mRNA levels of antioxidant enzymes and decreasing the expression of TXNIP, cleaved-Cas3, and inflammatory mediators. Taken together, our results showed that PYC attenuated TiO2NP-induced lung injury via TXNIP downregulation. Therefore, our results suggest the potential of PYC as an effective anti-inflammatory and antioxidant agent against TiO2NP-induced pulmonary toxicity. [ABSTRACT FROM AUTHOR]

Type I hypersensitivity reactions can result in pulmonary inflammation via increasing the bronchospasm and mucous secretions in the airways of lungs; however, the participation of neutrophils in pulmonary inflammation mediated by type I hypersensitivity reactions are incompletely understood. The present study thus aimed to examine the association between neutrophil recruitment and lung inflammation in patients with type I hypersensitivity reactions. For this purpose, blood samples, that were obtained from 128 individuals with type I hypersensitivity reactions and 40 individuals who served as the controls, were analyzed to measure the levels of immunoglobulin E (IgE), basophils, neutrophils, platelet distribution width (PDW) and red blood cell distribution width (RDW). Moreover, sputum neutrophils were also measured in both the patients and the controls. In addition, consolidation areas were identified by specialist radiologist staff. The results revealed a significant increase in the levels of IgE and basophils corresponding to 91 and 79%, respectively, in patients with type I hypersensitivity reactions. The present study also observed a marked increase in the number of neutrophils in the blood and sputum of patients. Moreover, the results revealed that the levels of PDW and RDW were significantly increased in the patients. In addition, a marked association (y=1.3061x+0.3546) (R²=0.7067) between the infiltrated neutrophils and the consolidation area in the lungs. On the whole, the present study demonstrates a notable association between neutrophil recruitment and lung inflammation in patients with type 1 hypersensitivity reactions; thus, neutrophils may prove useful as a therapeutic target for protection against pulmonary inflammation. Moreover, the presence of neutrophils in sputum may also be used as a biomarker of pulmonary inflammation mediated by type I hypersensitivity reactions. [ABSTRACT FROM AUTHOR]

The hemagglutinin (HA) and neuraminidase (NA) surface proteins are the primary and secondary immune targets for most influenza vaccines. In this study, H2, H5, H7, N1, and N2 antigens designed by the computationally optimized broadly reactive antigen (COBRA) methodology were incorporated into an adjuvant-formulated vaccine to assess the protective efficacy and immune response against A/Hong Kong/125/2017 H7N9 virus challenge in pre-immune mice. The elicited antibodies bound to H2, H5, H7, N1, and N2 wild-type antigens; cH6/1 antigens; and cH7/3 antigens, with hemagglutinin inhibition (HAI) activity against broad panels of the H2Nx, H5Nx, and H7Nx influenza strains. Mice vaccinated with the pentavalent COBRA HA/NA vaccine showed little to no weight loss, no clinical signs of diseases, and were protected from mortality when challenged with the lethal H7N9 virus. Virus titers in the lungs of vaccinated mice were lower and cleared more rapidly than in mock-vaccinated mice. Some vaccinated mice showed no detectable lung injury or inflammation. Antibody-secreting cells were significantly increased in COBRA-vaccinated mice, with higher total Ig and H7-specific ASC. Thus, the combination of H2, H5, H7, N1, and N2 COBRA antigens presents a potential for the formulation of a universal influenza virus vaccine. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally and is primarily caused by cigarette smoking (CS). Neurocognitive comorbidities such as anxiety and cognitive impairments are common among people with COPD. CS-induced lung inflammation and oxidative stress may "spill-over" into the systemic circulation, driving the onset of these comorbidities. We investigated whether a prophylactic treatment with the NADPH Oxidase 2 (NOX2) inhibitor, apocynin, could prevent CS-induced neurocognitive impairments. Adult male BALB/c mice were exposed to CS (9 cigarettes/day, 5 days/week) or room air (sham) for 8 weeks with co-administration of apocynin (5 mg/kg, intraperitoneal injection once daily) or vehicle (0.01% DMSO in saline). Following 7 weeks of CS exposure, mice underwent behavioral testing to assess recognition and spatial memory (novel object recognition and Y maze, respectively) and anxiety-like behaviors (open field and elevated plus maze). Mice were then euthanized, and blood, lungs, and brains were collected. Apocynin partially improved CS-induced lung neutrophilia and reversed systemic inflammation (C-reactive protein) and oxidative stress (malondialdehyde). Apocynin exerted an anxiolytic effect in CS-exposed mice, which was associated with restored microglial profiles within the amygdala and hippocampus. Thus, targeting oxidative stress using apocynin can alleviate anxiety-like behaviors and could represent a novel strategy for managing COPD-related anxiety disorders. [ABSTRACT FROM AUTHOR]

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe clinical disorders that mainly develop from viral respiratory infections, sepsis, and chest injury. Antigen-presenting cells play a pivotal role in propagating uncontrolled inflammation and injury through the excess secretion of pro-inflammatory cytokines and recruitment of immune cells. Autophagy, a homeostatic process that involves the degradation of cellular components, is involved in many processes including lung inflammation. Here, we use a polyinosinic-polycytidylic acid (poly(I:C))-induced lung injury mouse model to mimic viral-induced ALI/ARDS and show that disruption of autophagy in macrophages exacerbates lung inflammation and injury, whereas autophagy induction attenuates this process. Therefore, induction of autophagy in macrophages can be a promising therapeutic strategy in ALI/ARDS.

ABSTRACT Circulating extracellular vesicles (EVs) have been associated with the development of COVID-19 due to their roles in viral infection, inflammatory response, and thrombosis. However, the direct induction of lung inflammation by circulating EVs from severe COVID-19 patients remains unknown. EVs were extracted from the plasma of severe COVID-19 patients admitted to intensive care and healthy controls. To study the effect of COVID-19 EVs on lung inflammation, mice were intratracheally instilled with EVs. To examine the proinflammatory effects of EVs in vitro, bone marrow-derived macrophages were treated with EVs. COVID-19 but not control EVs triggered lung inflammation, as assessed by total protein level, total cell count, neutrophil count, and levels of proinflammatory cytokines in the bronchoalveolar lavage. COVID-19 EVs also promoted M1 polarization of alveolar macrophages in vivo. Treatment of bone marrow-derived macrophages with COVID-19 EVs enhanced the M1 phenotype and augmented the production of IL-1β, IL-6, and TNF-α. In summary, circulating EVs from severe COVID-19 patients induce lung inflammation in mice. EVs could become a potential therapeutic target for alleviating lung injury in COVID-19.IMPORTANCEExtracellular vesicles (EVs) have been reported to facilitate cytokine storm, coagulation, vascular dysfunction, and the spread of the virus in COVID-19. The direct role of circulating EVs from severe COVID-19 patients in lung injury remains unrecognized. Our study demonstrated that plasma EVs obtained from severe COVID-19 patients induced lung inflammation and polarization of alveolar macrophages in vivo. In vitro experiments also revealed the proinflammatory effects of COVID-19 EVs. The present study sheds fresh insight into the mechanisms of COVID-19-induced lung injury, highlighting EVs as a potential therapeutic target in combating the disease.

Asthma is a chronic inflammatory disease with many patients failing to respond appropriately to pharmacotherapy. Thus, virgin coconut oil (VCO) can be an alternative therapy. Guinea pigs were divided into control (Ctrl), chronic allergic lung inflammation (Asth), Asth treated with dexamethasone (Asth + dexa), and Asth supplemented with VCO (Asth + VCO4). The tested animals were sensitized and challenged with ovalbumin. Relaxation induced by arachidonic acid (AA) was impaired in Asth, and this reduction was prevented by VCO (p = 0.0004), indicating formation of relaxing prostanoids, or the decrease of cysteinyl-leukotrienes by VCO. Furthermore, a possible negative modulation of β receptors/BKCa pathway by TGF–β in Asth was prevented by VCO (p = 0.0073). Finally, in Asth, Masson’s trichrome staining revealed airway remodeling and immunohistochemistry showed increased TGF-β expression in the lungs of Asth (p

Hexavalent chromium (Cr(VI)) has been identified as a Class I human carcinogen, but its carcinogenic mechanism is currently unclear. There is still a lack of understanding of its associations with early pulmonary inflammatory damages. Inflammation is an important stage before the occurrence of tumors, and under the long-term stimulation of inflammation, it can promote the development of tumors. In this study, the aim is to explore the effect of Cr(VI) exposure on pulmonary inflammation and its relationship with the mechanism of inflammation cancer transformation. We established a Cr(VI) exposure model in SD rats using tracheal instillation of potassium dichromate solution, and collected samples at the time of cessation of exposure and 14 days after cessation of exposure. Analyzing the experimental results, it was found that the lung index increased after exposure to Cr(VI), promoting the occurrence of apoptosis in lung tissue cells and exacerbating lung tissue damage. The damage situation improved after exposure termination; Inductively coupled plasma mass (ICPRQ) spectrometer detection found that the exposed group had significantly increased levels of blood chromium, blood manganese, blood copper, blood arsenic, urine chromium, urine copper, and urine lead; After two weeks of repair, blood chromium and blood manganese levels were significantly lower than those in the same dose group of the exposure group, while blood copper levels were significantly higher than those in the same dose group of the exposure group. There was no significant difference in blood arsenic levels between the exposure group and the exposure group. Urine chromium and urine lead levels were significantly lower than those in the same dose group of the exposure group, while urine copper levels only increased. At the same time, it was found that Cr(VI) exposure caused disruption of oxidative stress levels in rat lung tissues. After 14-day exposure, Cr(VI) significantly decreased and oxidative stress levels significantly decreased. Further investigation revealed that Cr(VI) induces activation of inflammasomes NLRP3, AIM2, and their signaling pathways in lung inflammatory injuries, but this condition persists even after cessation of exposure. The study suggested that in hexavalent chromium induced lung tissue injuries in rats, NLRP3 and AIM2 inflammasomes and their signaling pathways activation. Furthermore, the characteristic of sustained activation after cessation of exposure was also indicated. These results provide new ideas and references for further elucidating the mechanisms of Cr(VI), lung inflammation and inflammation cancer transformation.

Abstract Type III interferons (λ1, λ2, and λ3) are potent antiviral cytokines in the lung. However, their roles in nonviral lung injuries are less well understood. This study investigates the activation of type III interferon signaling in three distinct models of lung injuries caused by diverse stimuli: the bacterial pathogen Pseudomonas aeruginosa, bacterial endotoxin LPS, and the chemotherapeutic agent bleomycin. Our data show that, despite inducing a potent inflammatory response, Pseudomonas and LPS did not increase IFNλ secretion. In contrast, bleomycin instillation increased secretion of IFNλ in the airways at both early and late time points. Consistent with limited secretion, type III interferon signaling had a minimal role in the host response to both Pseudomonas and LPS, as measured by pathogen burden, inflammatory response, and lung injury. Conversely, a deficiency in type III interferon signaling led to increased inflammatory signaling and elevated acute lung injury in the bleomycin model on day 3. This elevated early injury resulted in impaired recovery in IFNLR1 knockout mice, as evidenced by their recovery from bleomycin‐induced weight loss. Taken together, these data suggest a context‐specific activation of type III interferon signaling, where it plays an anti‐inflammatory role in the lung.

Abstract Gut microbiota is an intricate microbial community containing bacteria, fungi, viruses, archaea, and protozoa, and each of them contributes to diverse aspects of host health. Nevertheless, the influence of interaction among gut microbiota on host health remains uncovered. Here, we showed that the interaction between intestinal fungi and bacteria shaped lung inflammation during infection. Specifically, antifungal drug‐induced dysbiosis of gut mycobiota enhanced lung inflammation during infection. Dysbiosis of gut mycobiota led to gut Escherichia coli (E. coli) overgrowth and translocation to the lung during infection, which induced lung accumulation of the CD45+F4/80+Ly6G−Ly6C−CD11b+CD11c+ macrophages. Clearance of macrophages or deletion of TLR4 (Toll‐like receptor 4, recognition of LPS) rather than Dectin‐1 (recognition of beta‐1,3/1,6 glucans on fungi) blocked the antifungal drug‐induced aggravation of lung inflammation during infection. These findings suggest that the interaction between intestinal mycobiota and commensal bacteria affects host health through the gut–lung axis, offering a potential therapeutic target for ameliorating lung inflammation during infection.

Objective: In this study, to provide new methods for the treatment of Streptococcus pneumoniae infection, we aimed to describe the anti-inflammatory and antibacterial value of glycyrrhetinic acid on the basis of its inhibitory effect on bacterial growth (without killing the bacteria) and its reduction of the toxicity of S. pneumoniae. Methods: A mouse model was established via intranasal administration of Streptococcus pneumoniae D39, and glycyrrhetinic acid was subcutaneously injected for treatment. The wet‒dry ratio, bacterial flora content and inflammatory factor levels in the mouse lungs were determined. Cell experiments were used to evaluate glycyrrhetinic acid-mediated inhibition of PLY hemolysis and A549 cell death, and WB was used to measure glycyrrhetinic acid-mediated inhibition of PLY oligomerization. Results: Glycyrrhetinic acid reduced the levels of inflammatory factors, the dry‒wet ratio, the abundance of S. pneumoniae in the lungs of infected mice, pneumolysin-mediated A549 cell death, erythrocyte hemolysis and PLY oligoplasia. Conclusion: Glycyrrhetinic acid can reduce the virulence of S. pneumoniae by preventing the oligomerization of PLY.

Aflatoxin G1 (AFG1) is a mycotoxin commonly found in agricultural products, including dried fruits, meat, and milk products. Oral AFG1 administration induced tumor necrosis factor (TNF)-α-dependent chronic pulmonary inflammation, promoting AFG1-induced damage in alveolar epithelial cell, which is associated with lung adenocarcinoma. Pulmonary macrophages may be divided into tissue-resident alveolar macrophages (TRAMs) and monocyte-derived macrophages (MoMs), which involve in chronic lung inflammation. However, whether these macrophages contribute to AFG1-induced chronic pulmonary inflammation remains unknown. In this study, we found oral AFG1 administration disrupted the balance between TRAMs and MoMs, increasing MoMs infiltration and decreasing the number of TRAMs. AFG1 upregulated TNF-α expression in MoMs, but downregulated sialic acid binding Ig-like lectin F (Siglec-F) expression in TRAMs. Inhibition of TNF-α-dependent inflammation rescued the imbalance between TRAMs and MoMs in AFG1-treated lung tissues. Additionally, AFG1 stimulated MoMs differentiation to the proinflammatory M1 phenotype in vitro. Using a specific in vitro TRAM model, AFG1 downregulated Siglec-F and the M2 phenotypic markers arginase 1 and YM1, and upregulated the M1 phenotypic markers IL-6, iNOS and TNF-α, altering the TRAMs phenotype to the pro-inflammatory M1 phenotype in vitro. Additionally, mouse maternal dietary exposure to AFG1 caused an imbalance in pulmonary macrophages, decreasing TRAMs and increasing MoMs population in offspring, which was associated with proliferative lesions in the alveolar septa. Thus, dietary AFG1 exposure triggered an imbalance in pulmonary macrophages in both mother and offspring mice, and induced pro-inflammatory phenotypic alterations, which contributed to AFG1-induced chronic lung inflammation. These results provide clues to how AFG1-induced immunotoxicity and genotoxicity in humans might be prevented.

Although studies have suggested an association between lung infections and increased risk of neuronal disorders (e.g., dementia, cognitive impairment, and depressive and anxious behaviors), its mechanisms remain unclear. Thus, an experimental mice model of pulmonary sepsis was developed to investigate the relationship between lung and brain inflammation. Male Swiss mice were randomly assigned to either pneumosepsis or control groups. Pneumosepsis was induced by intratracheal instillation of Klebsiella pneumoniae, while the control group received a buffer solution. The model's validation included assessing systemic markers, as well as tissue vascular permeability. Depression- and anxiety-like behaviors and cognitive function were assessed for 30 days in sepsis survivor mice, inflammatory profiles, including cytokine levels (lungs, hippocampus, and prefrontal cortex) and microglial activation (hippocampus), were examined. Pulmonary sepsis damaged distal organs, caused peripheral inflammation, and increased vascular permeability in the lung and brain, impairing the blood-brain barrier and resulting in bacterial dissemination. After sepsis induction, we observed an increase in myeloperoxidase activity in the lungs (up to seven days) and prefrontal cortex (up to 24 h), proinflammatory cytokines in the hippocampus and prefrontal cortex, and percentage of areas with cells positive for ionized calcium-binding adaptor molecule 1 (IBA-1) in the hippocampus. Also, depression- and anxiety-like behaviors and changes in short-term memory were observed even 30 days after sepsis induction, suggesting a crosstalk between inflammatory responses of lungs and brain.

Introduction: Cystic fibrosis (CF) is an autosomal recessive genetic disease caused by a mutation in the CFTR gene. Characteristic symptoms include persistent lung infection, pancreatic insufficiency, and elevated sweat chloride, although many patients have mild or atypical symptoms. Diagnosis of CF is based primarily on the detection of genetic and/or functional abnormalities in the CFTR gene. Treatment includes pancreatic enzyme replacement therapy, mucolytic drugs, respiratory physiotherapy, and antibiotic therapy. Purpose of the work: This study aims to review and characterize the clinical and pathophysiological aspects of cystic fibrosis. Materials and methods: A comprehensive analysis of research papers available on PubMed, Google Scholar, Web of Science, Embase and Scopus was undertaken using the searchterms encompassing the following keywords: Cystic fibrosis, CFTR, Chloride Channels, Lung Inflammation, Diagnosis, Gene therapy, Treatment. Results: Cystic fibrosis is the most common, multisystem, life-threatening recessive disease in the white race. Although many organs are affected, the leading cause of morbidity and mortality is lung disease. Treatment requires pharmacotherapy, extensive physiotherapy, and nutritional support. In recent years, there has been significant progress in the diagnosis and treatment of cystic fibrosis, and the average survival has increased from a few to almost 50 years.

Idiopathic pulmonary fibrosis (IPF) is the most common and severe form of pulmonary fibrosis, characterized by scar formation in the lung interstitium. Transforming growth factor beta (TGF-β) is known as a key mediator in the fibrotic process, acting on fibroblasts and mediating their proliferation and differentiation into myofibroblasts. Although the immune system is not considered responsible for the initiation of IPF, markers of tolerogenic immunity define the pro-fibrotic microenvironment in the lungs. In homeostatic conditions, regulatory T cells (Tregs) constitute the main lymphoid population responsible for maintaining peripheral tolerance. Similar to Tregs, regulatory B cells (Bregs) represent a recently described subset of B lymphocytes with immunosuppressive functions. In the context of IPF, numerous studies have suggested a role for Tregs in enhancing fibrosis, mainly via the secretion of TGF-β. In humans, most studies show increased percentages of Tregs associated with the severity of IPF, although their exact role remains unclear. In mice, the most commonly used model involves triggering acute lung inflammation with bleomycin, leading to a subsequent fibrotic process. Consequently, data are still conflicting, as Tregs may play a protective role during the inflammatory phase and a deleterious role during the fibrotic phase. Bregs have been less studied in the context of IPF, but their role appears to be protective in experimental models of lung fibrosis. This review presents the latest updates on studies exploring the implication of regulatory lymphoid cells in IPF and compares the different approaches to better understand the origins of conflicting findings.

Silicosis is an irreversible interstitial lung fibrosis resulting from persistent inflammation induced by long-term inhalation of SiO2 dust. Treatment and early diagnosis are extremely challenging due to the lack of specific targets and biomarkers. MiRNAs play an important role in the early diagnosis and treatment of various diseases, due to their stability, small variations, and easy detection. Exosomes have become fashionable candidates to deliver miRNAs. However, the specific role of exosomes-loaded miRNAs in silicosis inflammation and fibrosis remains unclear. In the present study, the expression profile of serum exosomal miRNAs in the peripheral blood of silicosis patients was determined by transcritome sequencing. MiR-23a-3p was recognized as a protector against silicosis by bioinformatic analysis. The expression and regulatory axis of miR-23a-3p and its predicted target gene CUL3 were then confirmed. The therapeutic role of the miR-23a-3p/CUL3 axis and its alleviating effect on SiO2-induced apoptosis were verified in mice and in epithelial cells. Furthermore, the communication of exosomes carrying miR-23a-3p between macrophages and epithelial cells was demonstrated using a cell co-culture model. Our results suggest that exosomal miR-23a-3p could be prospective as a biomarker in early diagnose for SiO2-induced lung fibrosis, and provided new threads for the treatment of silicosis.

Prolonged inhalation of environmental crystalline silica (CS) can cause silicosis, characterized by persistent pulmonary inflammation and irreversible fibrosis, but the mechanism has not been elucidated. To uncover the role and underlying mechanism of glycolytic reprogramming in CS-induced pulmonary inflammation, the mouse silicosis models and glycolysis inhibition models were established in vivo. And the CS-induced macrophage activation models were utilized to further explore the underlying mechanism in vitro. The results showed that CS induced lung inflammation accompanied by glycolytic reprogramming and pyroptosis. The application of glycolysis inhibitor (2-DG) suppressed CS-induced pyroptosis and alleviated lung inflammation. In vitro, 2-DG effectively impeded CS-induced macrophage pyroptosis and inflammatory response. Mechanistically, 2-DG suppressed pyroptosis by inhibiting NLRP3 inflammasome activation both in vivo and in vitro. Furtherly, metabolite lactate facilitated NLRP3-dependent pyroptosis synergistically with CS particles, while blocking the source of lactate largely alleviated NLRP3 inflammasome activation and subsequent pyroptosis triggered by CS. More profoundly, the increment of lactate induced by CS might drive NLRP3-dependent pyroptosis by increasing histone lactylation levels. In conclusion, our findings demonstrated inhibiting glycolytic reprogramming could alleviate CS-induced inflammatory response through suppressing NLRP3 -dependent pyroptosis. Increased glycolytic metabolite lactate and protein lactylation modifications might represent significant mechanisms during CS-induced NLRP3 activation and macrophage pyroptosis.

Objective To identify the effective components and key molecules of Yiqi Huoxu compound(YQHX) in the treatment of pulmonary inflammation and fibrosis in scleroderma, providing basis for the development of drug targets for scleroderma. Methods A mouse model of pulmonary fibrosis was established by a single tracheal perfusion of bleomycin. Twenty-four mice were randomly divided into four groups, i.e. intragastric PBS, bleomycin alone, intragastric Yiqi Huoxue compound, and control. HE staining and Masson staining were used to verify the therapeutic effect of Yiqi Huoxue compound on lung inflammation and fibrosis. The active components and target genes of anti-fiber salvia miltiorrhiza were obtained from TCMSP database. PPI network, GO/KEGG enrichment analysis, molecular docking and other bioinformatics analyses were integrated to identify the main active ingredients and key targets of salvia miltiorrhiza in the treatment of scleroderma, and to analyze the relevant signaling pathways. The expression levels of CD3 antibody, p-PI3K antibody and p-AKT antibody were analyzed by immunohistochemistry to verify the effects of Yiqi Huoxu compound on inflammation and key pathways. Results The results of HE staining and Masson staining showed that the severity of fibrosis and inflammatory infiltration were decreased, suggesting that Yiqi Huoxue compound could significantly improve the pulmonary fibrosis, inflammation and tissue damages. The key component of salvia miltiorrhiza was mainly luteolin. PPI network analysis showed that AKT1, EGFR, ESR1, TNF and IL6 were the core targets of salvia miltiorrhiza in the treatment of scleroderma. KEGG enrichment analysis showed that the genes were mainly enriched in the PI3K-AKT pathway. Molecular docking analysis showed the potential binding sites between luteolin and four key targets. The immunohistochemical results showed that YQHX significantly decreased bleomycin-induced CD3+T cell infiltration, p-PI3K and p-AKT levels in mouse lung tissue. Conclusions YQHX has significant therapeutic effects on lung inflammation and fibrosis. Luteolin may be a key effective molecule in YQHX, and treat scleroderma lung inflammation and fibrosis by targeting the PI3K-AKT pathway.

Abstract Introduction PM exposure can induce inflammatory and oxidative responses; however, differences in these adverse effects have been reported depending on the chemical composition and size. Moreover, inflammatory mechanisms such as NLRP3 activation by PM10 have yet to be explored. Objective To assess the impact of PM10 on cell cytotoxicity and the inflammatory response through in vitro and in vivo models. Methodology Peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed to PM10. Cytotoxicity was determined using the LDH assay; the expression of inflammasome components and the production of pro-inflammatory cytokines were quantified through qPCR and ELISA, respectively; and the formation of ASC complexes was examined using confocal microscopy. For in vivo analysis, male C57BL6 mice were intranasally challenged with PM10 and bronchoalveolar lavage fluid was collected to determine cell counts and quantification of pro-inflammatory cytokines by ELISA. RNA was extracted from lung tissue, and the gene expression of inflammatory mediators was quantified. Results PM10 exposure induced significant cytotoxicity at concentrations over 100 µg/mL. Moreover, PM10 enhances the gene expression and release of pro-inflammatory cytokines in PBMCs, particularly IL-1β; and induces the formation of ASC complexes in a dose-dependent manner. In vivo, PM10 exposure led to cell recruitment to the lungs, which was characterized by a significant increase in polymorphonuclear cells compared to control animals. Furthermore, PM10 induces the expression of several inflammatory response-related genes, such as NLRP3, IL-1β and IL-18, within lung tissue. Conclusion Briefly, PM10 exposure reduced the viability of primary cells and triggered an inflammatory response, involving NLRP3 inflammasome activation and the subsequent production of IL-1β. Moreover, PM10 induces the recruitment of cells to the lung and the expression of multiple cytokines; this phenomenon could contribute to epithelial damage and, thus to the development and exacerbation of respiratory diseases such as viral infections.

BACKGROUND: Ibuprofen is a nonsteroidal anti-inflammatory drug that is commonly used to stimulate closure of a patent ductus arteriosus (PDA) in very premature infants and may lead to aberrant neonatal lung development and bronchopulmonary dysplasia (BPD). METHODS: We investigated the effect of ibuprofen on angiogenesis in human umbilical cord vein endothelial cells (HUVECs) and the therapeutic potential of daily treatment with 50 mg/kg of ibuprofen injected subcutaneously in neonatal Wistar rat pups with severe hyperoxia-induced experimental BPD. Parameters investigated included growth, survival, lung histopathology and mRNA expression. RESULTS: Ibuprofen inhibited angiogenesis in HUVECs, as shown by reduced tube formation, migration and cell proliferation via inhibition of the cell cycle S-phase and promotion of apoptosis. Treatment of newborn rat pups with ibuprofen reduced pulmonary vessel density in the developing lung, but also attenuated experimental BPD by reducing lung inflammation, alveolar enlargement, alveolar septum thickness and small arteriolar wall thickening. CONCLUSIONS: In conclusion, ibuprofen has dual effects on lung development: adverse effects on angiogenesis and beneficial effects on alveolarization and inflammation. Therefore, extrapolation of the beneficial effects of ibuprofen to premature infants with BPD should be done with extreme caution.

Elevated TNF-α levels in serum and broncho-alveolar lavage fluid of acute lung injury patients correlate with mortality rates. We hypothesized that pharmacological plasma membrane potential (Em) hyperpolarization protects against TNF-α-induced CCL-2 and IL-6 secretion from human pulmonary endothelial cells through inhibition of inflammatory Ca2+-dependent MAPK pathways. Since the role of Ca2+ influx in TNF-α-mediated inflammation remains poorly understood, we explored the role of L-type voltage-gated Ca2+ (CaV) channels in TNF-α-induced CCL-2 and IL-6 secretion from human pulmonary endothelial cells. The CaV channel blocker, Nifedipine, decreased both CCL-2 and IL-6 secretion, suggesting that a fraction of CaV channels is open at the significantly depolarized resting Em of human microvascular pulmonary endothelial cells (-6 ± 1.9 mV), as shown by whole-cell patch-clamp measurements. To further explore the role of CaV channels in cytokine secretion, we demonstrated that the beneficial effects of Nifedipine could also be achieved by Em hyperpolarization via the pharmacological activation of large conductance K+ (BK) channels with NS1619, which elicited a similar decrease in CCL-2 but not IL-6 secretion. Using functional gene enrichment analysis tools, we predicted and validated that known Ca2+-dependent kinases, JNK-1/2 and p38, are the most likely pathways to mediate the decrease in CCL-2 secretion.

BackgroundElectronic cigarettes (eC) may not be entirely benign. There is a lack of data on the effect of a single acute exposure of eC vapor using various heating sources and power settings upon lung injury. The purpose of this study was to determine if an acute exposure with eC vapor heated with different heating elements and power levels induced inflammatory changes in the lungs and heart.MethodsRats were exposed to pure air or received a single, 4-h exposure to eC vapor. The devices used either a stainless steel (SS) or nichrome (NC) heating element randomized to a low or high atomization power (45 versus 70 W). Rats were euthanized within 48 h of exposure.ResultsThe eC groups showed accumulation of inflammatory cells in bronchial lumen, near the pleura, and within the alveolar spaces. The numbers of inflammatory cells per field in the lung parenchyma were significantly greater in the rats exposed to eC groups vs. the air group. There were significantly higher inflammatory gene expression changes in the lungs of animals assigned to 70 W power. We observed that eC vapor generated using burnt coils were toxic and could cause acute respiratory distress and myocarditis.ConclusionIn conclusion, one 4-h exposure to eC vapor, in the absence of vitamin E oil or nicotine, significantly increased lung inflammation. Effects were seen after exposures to vapor generated using SS and NC heating elements at either high or low power. Vapor from devices with burnt coils can negatively affect the heart and lung.

Background: Cytokine storm and oxidative stress are present in chronic obstructive pulmonary disease (COPD). Individuals with COPD present high levels of NF-κB-associated cytokines and pro-oxidant agents as well as low levels of Nrf2-associated antioxidants. This condition creates a steroid-resistant inflammatory microenvironment. Lacticaseibacillus rhamnosus (Lr) is a known anti-cytokine in lung diseases; however, the effect of Lr on lung inflammation and oxidative stress in steroid-resistant COPD mice remains unknown. Objective: Thus, we investigated the Lr effect on lung inflammation and oxidative stress in mice and macrophages exposed to cigarette smoke extract (CSE) and unresponsive to steroids. Methods: Mice and macrophages received dexamethasone or GLPG-094 (a GPR43 inhibitor), and only the macrophages received butyrate (but), all treatments being given before CSE. Lung inflammation was evaluated from the leukocyte population, airway remodeling, cytokines, and NF-κB. Oxidative stress disturbance was measured from ROS, 8-isoprostane, NADPH oxidase, TBARS, SOD, catalase, HO-1, and Nrf2. Results: Lr attenuated cellularity, mucus, collagen, cytokines, ROS, 8-isoprostane, NADPH oxidase, and TBARS. Otherwise, SOD, catalase, HO-1, and Nrf2 were upregulated in Lr-treated COPD mice. Anti-cytokine and antioxidant effects of butyrate also occurred in CSE-exposed macrophages. GLPG-094 rendered Lr and butyrate less effective. Conclusions: Lr attenuates lung inflammation and oxidative stress in COPD mice, suggesting the presence of a GPR43 receptor-dependent mechanism also found in macrophages. [ABSTRACT FROM AUTHOR]

Objective To identify the effective components and key molecules of Yiqi Huoxu compound (YQHX) in the treatment of pulmonary inflammation and fibrosis in scleroderma, providing basis for the development of drug targets for scleroderma. Methods A mouse model of pulmonary fibrosis was established by a single tracheal perfusion of bleomycin. Twenty-four mice were randomly divided into four groups, i. e. intragastric PBS, bleomycin alone, intragastric Yiqi Huoxue compound, and control. HE staining and Masson staining were used to verify the therapeutic effect of Yiqi Huoxue compound on lung inflammation and fibrosis. The active components and target genes of anti-fiber salvia miltiorrhiza were obtained from TCMSP database. PPI network, GO/KEGG enrichment analysis, molecular docking and other bioinformatics analyses were integrated to identify the main active ingredients and key targets of salvia miltiorrhiza in the treatment of scleroderma, and to analyze the relevant signaling pathways. The expression levels of CD3 antibody, p-PI3K antibody and p-AKT antibody were analyzed by immunohistochemistry to verify the effects of Yiqi Huoxu compound on inflammation and key pathways. Results The results of HE staining and Masson staining showed that the severity of fibrosis and inflammatory infiltration were decreased, suggesting that Yiqi Huoxue compound could significantly improve the pulmonary fibrosis, inflammation and tissue damages. The key component of salvia miltiorrhiza was mainly luteolin. PPI network analysis showed that AKT1, EGFR, ESR1, TNF and II6 were the core targets of salvia miltiorrhiza in the treatment of scleroderma. KEGG enrichment analysis showed that the genes were mainly enriched in the PI3K-AKT pathway. Molecular docking analysis showed the potential binding sites between luteolin and four key targets. The immunohistochemical results showed that YQHX significantly decreased bleomycin-induced CD3 + T cell infiltration, p-PI3K and p-AKT levels in mouse lung tissue. Conclusions YQHX has significant therapeutic effects on lung inflammation and fibrosis. Luteolin may be a key effective molecule in YQHX, and treat scleroderma lung inflammation and fibrosis by targeting the PI3K-AKT pathway. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS) is a critical illness characterized by severe lung inflammation. Improving the delivery efficiency and achieving the controlled release of anti-inflammatory drugs at the lung inflammatory site are major challenges in ARDS therapy. Taking advantage of the increased pulmonary vascular permeability and a slightly acidic-inflammatory microenvironment, pH-responsive mineralized nanoparticles based on dexamethasone sodium phosphate (DSP) and Ca2+ were constructed. By further biomimetic modification with M2 macrophage membranes, hybrid mineralized nanovesicles (MM@LCaP) were designed to possess immunomodulatory ability from the membranes and preserve the pH-sensitivity from core nanoparticles for responsive drug release under acidic inflammatory conditions. Compared with healthy mice, the lung/liver accumulation of MM@LCaP in inflammatory mice was increased by around 5.5 times at 48 h after intravenous injection. MM@LCaP promoted the polarization of anti-inflammatory macrophages, calmed inflammatory cytokines, and exhibited a comprehensive therapeutic outcome. Moreover, MM@LCaP improved the safety profile of glucocorticoids. Taken together, the hybrid mineralized nanovesicles-based drug delivery strategy may offer promising ideas for enhancing the efficacy and reducing the toxicity of clinical drugs. Hybrid mineralized nanovesicles improved the drug delivery efficiency to the lungs, suppressed the inflammatory conditions effectively, and meanwhile reduced side effects of glucocorticoids. [Display omitted] • Dexamethasone-based mineralized nanoparticles achieved pH-responsive drug release behavior. • Biomimetic modification enhanced immunomodulatory ability. • Hybrid mineralized nanovesicles increased lung accumulation based on ELVIS effect and improved the safety profile of glucocorticoids. [ABSTRACT FROM AUTHOR]

Excessive or persistent inflammation may have detrimental effects on lung structure and function. Currently, our understanding of conserved host mechanisms that control the inflammatory response remains incompletely understood. In this study, we investigated the role of type I interferon signaling in the inflammatory response against diverse clinically relevant stimuli. Using mice deficient in type I interferon signaling (IFNAR1−/−), we demonstrate that the absence of interferon signaling resulted in a robust and persistent inflammatory response against Pseudomonas aeruginosa, lipopolysaccharide, and chemotherapeutic agent bleomycin. The elevated inflammatory response in IFNAR1−/− mice was manifested as elevated myeloid cells, such as macrophages and neutrophils, in the bronchoalveolar lavage. The inflammatory cell response in the IFNAR1−/− mice persisted to 14 days and there is impaired recovery and fibrotic remodeling of the lung in IFNAR1−/− mice after bleomycin injury. In the Pseudomonas infection model, the elevated inflammatory cell response led to improved bacterial clearance in IFNAR1−/− mice, although there was similar lung injury and survival. We performed RNA sequencing of lung tissue in wild-type and IFNAR1−/− mice after LPS and bleomycin injury. Our unbiased analysis identified differentially expressed genes between IFNAR1−/− and wild-type mice, including previously unknown regulation of nucleotide-binding oligomerization domain (NOD)-like receptor signaling, retinoic acid-inducible gene-I (RIG-I) signaling, and necroptosis pathway by type I interferon signaling in both models. These data provide novel insights into the conserved anti-inflammatory mechanisms of the type I interferon signaling. NEW & NOTEWORTHY: Type I interferons are known for their antiviral activities. In this study, we demonstrate a conserved anti-inflammatory role of type I interferon signaling against diverse stimuli in the lung. We show that exacerbated inflammatory response in the absence of type I interferon signaling has both acute and chronic consequences in the lung including structural changes. [ABSTRACT FROM AUTHOR]

Introduction: PM exposure can induce inflammatory and oxidative responses; however, differences in these adverse effects have been reported depending on the chemical composition and size. Moreover, inflammatory mechanisms such as NLRP3 activation by PM10 have yet to be explored. Objective: To assess the impact of PM10 on cell cytotoxicity and the inflammatory response through in vitro and in vivo models. Methodology: Peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed to PM10. Cytotoxicity was determined using the LDH assay; the expression of inflammasome components and the production of pro-inflammatory cytokines were quantified through qPCR and ELISA, respectively; and the formation of ASC complexes was examined using confocal microscopy. For in vivo analysis, male C57BL6 mice were intranasally challenged with PM10 and bronchoalveolar lavage fluid was collected to determine cell counts and quantification of pro-inflammatory cytokines by ELISA. RNA was extracted from lung tissue, and the gene expression of inflammatory mediators was quantified. Results: PM10 exposure induced significant cytotoxicity at concentrations over 100 µg/mL. Moreover, PM10 enhances the gene expression and release of pro-inflammatory cytokines in PBMCs, particularly IL-1β; and induces the formation of ASC complexes in a dose-dependent manner. In vivo, PM10 exposure led to cell recruitment to the lungs, which was characterized by a significant increase in polymorphonuclear cells compared to control animals. Furthermore, PM10 induces the expression of several inflammatory response-related genes, such as NLRP3, IL-1β and IL-18, within lung tissue. Conclusion: Briefly, PM10 exposure reduced the viability of primary cells and triggered an inflammatory response, involving NLRP3 inflammasome activation and the subsequent production of IL-1β. Moreover, PM10 induces the recruitment of cells to the lung and the expression of multiple cytokines; this phenomenon could contribute to epithelial damage and, thus to the development and exacerbation of respiratory diseases such as viral infections. [ABSTRACT FROM AUTHOR]

Introduction: Asthma is a condition of airflow limitation, common throughout the world, with high mortality rates, especially as it still faces some obstacles in its management. As it constitutes a public health challenge, this study aimed to investigate the effect of copaiba oil (e.g., Copaifera langsdorffii), as a treatment resource, at doses of 50 and 100 mg/kg on certain mediators of acute lung inflammation (IL-33, GATA3, FOXP3, STAT3, and TBET) and early mechanisms of lung remodeling (degradation of elastic fiber tissues, collagen deposition, and goblet cell hyperplasia). Methods: Using an ovalbumin-induced acute allergic asthma model in BALB/c mice, we analyzed the inflammatory mediators through immunohistochemistry and the mechanisms of lung remodeling through histopathology, employing orcein, Masson's trichrome, and periodic acid-Schiff staining. Results: Copaiba oil treatment (CO) reduced IL-33 and increased FOXP3 by stimulating the FOXP3/GATA3 and FOXP3/STAT3 pathways. Additionally, it upregulated TBET, suggesting an additional role in controlling GATA3 activity. In the respiratory epithelium, CO decreased the fragmentation of elastic fibers while increasing the deposition of collagen fibers, favoring epithelial restructuring. Simultaneously, CO reduced goblet cell hyperplasia. Discussion: Although additional research is warranted, the demonstrated antiinflammatory and re-epithelializing action makes CO a viable option in exploring new treatments for acute allergic asthma. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The removal of dead cells (efferocytosis) contributes to the resolution of the infection and preservation of the tissue. Depending on the environment milieu, macrophages may show inflammatory (M1) or anti-inflammatory (M2) phenotypes. Inflammatory leukocytes are recruited during infection, followed by the accumulation of infected and non-infected apoptotic cells (AC). Efferocytosis of non-infected AC promotes TGF-β, IL-10, and PGE2 production and the polarization of anti-inflammatory macrophages. These M2 macrophages acquire an efficient ability to remove apoptotic cells that are involved in tissue repair and resolution of inflammation. On the other hand, the impact of efferocytosis of infected apoptotic cells on macrophage activation profile remains unknown. Here, we are showing that the efferocytosis of gram-positive Streptococcus pneumoniae-AC (Sp-AC) or gram-negative Klebsiella pneumoniae-AC (Kp-AC) promotes distinct gene expression and cytokine signature in macrophages. Whereas the efferocytosis of Kp-AC triggered a predominant M1 phenotype in vitro and in vivo, the efferocytosis of Sp-AC promoted a mixed M1/M2 activation in vitro and in vivo in a model of allergic asthma. Together, these findings suggest that the nature of the pathogen and antigen load into AC may have different impacts on inducing macrophage polarization. [ABSTRACT FROM AUTHOR]

Excessive alcohol consumption increases the severity and worsens outcomes of pulmonary infections, often due to oxidative stress and tissue damage. While the mechanism behind this relationship is multifaceted, recent evidence suggests ethanol-induced changes to the gut microbiome impact the gut–lung axis. To assess this, a chronic–binge ethanol feeding mouse model was used to determine how ethanol altered the gut microbiome, small intestinal epithelial barrier, and immune responses, as well as neutrophil abundance and oxidative stress in the lungs, and how supporting gut health with tributyrin supplementation during chronic–binge ethanol exposure affected these responses. We found that ethanol consumption altered gut bacterial taxa and metabolic processes, distorted small intestinal immune responses, and induced both bacteria and endotoxin translocation into the lymphatic and circulatory systems. These changes were associated with increased neutrophil (Ly6G) presence and markers of oxidative stress, lipocalin-2 and myeloperoxidase, in the lungs. Importantly, tributyrin supplementation during ethanol exposure rescued gut bacterial function (p < 0.05), small intestinal barrier integrity, and immune responses, as well as reducing both Ly6G mRNA (p < 0.05) and lipocalin-2 mRNA (p < 0.01) in the lungs. These data suggest ethanol-associated disruption of gut homeostasis influenced the health of the lungs, and that therapeutics supporting gut health may also support lung health. [ABSTRACT FROM AUTHOR]

[Objectives]This study aimed to investigate the effect of the pulmonary microbiota on PM2.5-induced lung inflammatory injury in broilers and to explore the role of Enterococcus cecorum on PM2.5-induced lung inflammatory injury using E.cecorum-treated alveolar epithelial cells. [Methods]A total of fourty-five male AA broilers(19-day-old)were randomly divided into three groups:the control group, the PM2.5 group(PM), and the pulmonary microbiota-intervened group(ABX-PM). From 21 days of age, broilers in the ABX-PM group were intratracheally instilled with antibiotics once a day for three days. Meanwhile, broilers in the other two groups were simultaneously instilled with sterile saline. At 24 and 26 days of age, broilers in the PM and ABX-PM groups were intratracheally instilled with PM2.5 suspension to induce lung inflammatory injury, and broilers in the control group were simultaneously instilled with sterile saline. Twenty-four hours after the last intratracheal instillation of PM2.5, we weighed the broilers and collected lung tissue, bronchoalveolar lavage fluid(BALF), and serum samples. We measured the levels of inflammatory factors in BALF and serum. Besides, we measured the gene expression levels of tight junctions(TJ)protein, the relative content of Enterococcus spp. and E.cecorum in the lung tissue, and the correlation between the relative content of E.cecorum and inflammatory factor levels. In addition, type Ⅱ alveolar epithelial cells(A549)were cultured and divided into two groups. The control group was treated with DMEM/F12 medium without E.cecorum, while the E.cecorum treatment group was treated with DMEM/F12 medium containing 1×104 CFU·mL-1 E.cecorum. We compared the gene expression levels of inflammatory factors, TJ, and apoptosis between the two groups after 6 h of treatment. [Results]The levels of IL-8 in BALF and serum, as well as the mRNA expression levels of occludin and claudin-1 in lung tissue, were significantly higher in the PM group than those in the control group. The claudin-5 mRNA expression level was significantly lower in the PM group than the control group, but the above indicators were not statistically different in the ABX-PM group compared to the control group. The relative contents of Enterococcus spp. and E.cecorum in the PM group were significantly higher than those in the control and ABX-PM groups. The relative content of E.cecorum was significantly positively correlated with the levels of IL-1β, IL-6, and IL-8 in BALF and IL-1β in serum. In the cellular experiment, the mRNA expression levels of tnf-α, il-1β, il-6, and il-8 were significantly higher, while the mRNA expression level of il-10 was significantly lower in the E.cecorum treatment group than those in the control group. The mRNA expression levels of zo-1 and claudin-1 in the E.cecorum treatment group were significantly higher than those in the control group. The ratio of bax/bcl-2 mRNA expression levels and the mRNA expression level of caspase-3 were significantly higher, while the mRNA expression level of bcl-2 was significantly lower in the E.cecorum treatment group than those in the control group. [Conclusions]The pulmonary microbiota intervention reduced PM2.5-induced proliferation of E.cecorum, and alleviated the degree of lung inflammatory injury in broilers, indicating the involvement of pulmonary microbiota in the process of PM2.5-induced lung inflammation injury in broilers. Moreover, E.cecorum could induce an inflammatory response in alveolar epithelial cells, which suggested that the imbalance of pulmonary microbiota aggravated lung inflammation injury. [ABSTRACT FROM AUTHOR]