Search Results (173)

Obesity is a significant health issue, as it is related to human diseases such as asthma and respiratory viral infections. Asthma patients with obesity have more severe diseases, which can be presented with type 1 (e.g., IFN-γ) high inflammation. The interactions of obesity or saturated fatty acids (e.g., palmitic acid, PA) with IFN-γ in airway viral infections have not been clear. In this study, we determined the role of obesity risk factors high-fat diet (HFD) and PA in rhinovirus infection in the context of IFN-γ stimulation in mice and cultured human tracheobronchial epithelial cells. We further examined the therapeutic effect of a glycolytic inhibitor on metabolic reprogramming and viral infection in our experimental models. In mice, HFD in combination with IFN-γ significantly increased lung rhinovirus levels as well as neutrophilic inflammation. Similarly, PA and IFN-γ combination increased viral infection in mice, but HFD or PA alone had a minimal effect on viral infection. Mouse model data were confirmed in cultured primary healthy human airway epithelial cells where PA and IFN-γ together increased viral load. Mechanistically, HFD or PA in combination with IFN-γ up-regulated the glycolytic pathway and generated metabolites favoring viral replication. Inhibition of glycolysis by 2-DG effectively reduced viral infection in human airway epithelial cells. Our data suggest that hosts with obesity along with type 1 high inflammation may be at an increased risk of respiratory viral infections. Intervention of the glycolytic pathway or its metabolites may reduce the severity of viral infection. Full article

Objectives: Despite advancements in molecular-targeted therapies and immune checkpoint inhibitors, the survival rate of patients with advanced lung cancer remains unsatisfactory. Therefore, new and effective treatment strategies are urgently needed. Both mesenchymal-epithelial transition (MET) inhibitors and oncolytic viruses exhibit immunomodulatory properties along with direct antitumor effects. Materials and Methods: The antitumor effects of a combination therapy using MDRVV, a modified vaccinia virus for oncolytic virus therapy, and tepotinib, a MET inhibitor, were evaluated in vitro and in vivo using lung cancer models. Results: The combination therapy demonstrated additive cytotoxic effects on various lung cancer cell lines in vitro and significantly suppressed tumor growth in an immunocompetent mouse model. MDRVV triggered immunogenic cell death, evidenced by the release of adenosine triphosphate (ATP) and high-mobility group box-1 (HMGB-1). Additionally, the combination therapy enhanced CD4+ and CD+ T-cell infiltration more effectively than either agent alone. MDRVV exhibited antitumor effects not only in the inoculated tumors but also in distant tumors, with the most pronounced effect observed when combined with tepotinib. Conclusions: These findings suggest that combining a MET inhibitor with oncolytic vaccinia virus represents a promising and effective strategy for improving lung cancer treatment by targeting both tumor cells and the tumor microenvironment. Full article

Intrauterine inflammation (IUI) is involved in the development of bronchopulmonary dysplasia (BPD). Previously, we observed BPD-like pathological changes in a mouse model of IUI. This study aimed to identify the key molecules involved in IUI-induced lung injury, focusing on NR4A1. Pregnant C57BL/6 mice were randomly divided into control and IUI groups. To verify the intervention effects, Nr4a1 siRNA was administered intranasally on postnatal day 3, while an NR4A1 overexpression plasmid was applied in MLE-12 cells to investigate downstream molecules. We found that the lungs of IUI-induced offspring exhibited a simplified structure on postnatal day 1 and excessive collagen fiber deposition by day 90. Postnatal NR4A1 intervention reversed IUI-induced neonatal lung injury. NR4A1 overexpression reduced cell proliferation and AKT and ERK1/2 phosphorylation levels, while also affecting the expression of the key epithelial–mesenchymal transition (EMT)-related gene TGF-β. EREG is a downstream target with potential NR4A1 binding sites in its promoter region. The expression of EMT-related genes can be recovered by blocking the receptor of EREG. Our findings imply that IUI induces BPD-like lung injury in neonates and fibrosis-like lung lesions in adult mice. The NR4A1-EREG-EGFR signaling pathway in pulmonary epithelial cells is crucial in IUI-induced lung injury, highlighting a key therapeutic target for mitigating BPD-like injury. Full article

Among the molecules implicated in inflammation-associated tumorigenesis, Chitinase 3-like 1 (CHI3L1/YKL-40/Brp-39) has emerged as a particularly compelling target due to its multifaced roles in immune regulation, tissue remodeling, and cancer progression. Elevated CHI3L1 expression is observed in various human cancers and corresponding animal models. CHI3L1 directly promotes tumor cell proliferation and angiogenesis and also contributes to immune evasion by establishing an immunosuppressive environment in inflamed tissues. Mechanistically, CHI3L1 exerts its effects through the modulation of STAT3, MAPK, and PI3K/Akt signaling pathways and by interacting with cell surface receptors, such as IL-13Rα2 and RAGE. Studies using transgenic and knockout mouse models have revealed a strong association between CHI3L1 expression and cancer progression. In models of colon and lung cancer, CHI3L1 overexpression correlates with increased tumor size and number, whereas CHI3L1 deficiency markedly suppresses tumor formation. However, its involvement appears to be context-dependent and varies among different epithelial tumor types. These findings suggest that CHI3L1 is a potential therapeutic target and diagnostic biomarker for inflammation-associated cancers. Animal studies provide valuable insights into the immunological mechanisms of CHI3L1-mediated tumorigenesis but also highlight the need for cautious interpretation due to inherent technical limitations. Full article

Immune function declines with age, leading to increased vulnerability of the elderly to viral infectious pathogens. The mechanisms by which aging negatively impacts the innate and adaptive immune system, leading to enhanced susceptibility to respiratory viral pathogens, remain incompletely understood. In the present study, we utilized a mouse model of infection with herpes simplex virus type 1 (HSV-1), a virus that can infect the lungs and lead to pneumonia, a rare but serious health concern in the elderly. Following intranasal inoculation of young (6 weeks), adult (36 weeks), and aged mice (68 weeks) with HSV-1 (KOS strain) we: (i) compared the local and systemic immune responses to infection in young, adult, and aged mice, and (ii) correlated the level and type of immune responses to protection against HSV-1 infection and disease. Compared to young and adult mice, aged mice displayed: (i) increased activation of epithelial cells with a decreased expression of TLR3; (ii) increased activation of dendritic cells with increased expression of MHC-I, MHC-II, and CD80/86; (iii) decreased production of type-I interferons; (iv) delayed production of anti-inflammatory cytokines and chemokines in the lungs; and (v) impairment frequencies of functional HSV-specific CD107+IFN-γ+CD8+ T cells associated with the increased incidence of viral infection and disease. These findings suggest that age-related impairments in innate and adaptive immune responses may exacerbate respiratory viral infections and disease in the elderly. Full article

Background: Naringenin has demonstrated potential therapeutic effects against cigarette smoke-induced lung injury; however, its underlying mechanisms of regulating matrix metalloproteinase-9 (MMP-9) in alveolar macrophages remain unclear. Methods: The regulatory mechanisms of naringenin in cigarette smoke extract (CSE)-induced alveolar macrophages were investigated using proteomics, and then, naringenin’s targets were further validated by Western blot, molecular docking, molecular dynamics (MD) simulations, cellular thermal shift assay (CETSA), and enzyme activity assay. Results: The proteomics revealed that the PI3K/AKT signaling pathway might play a crucial role in naringenin’s inhibition of MMP-9. Western blot analysis confirmed that naringenin significantly inhibited CSE-upregulated PI3K/AKT signaling pathway and reduced MMP-9 expression in MH-S cells. Notably, the PI3K activator 740Y-P reversed naringenin’s effects on MMP-9. Additionally, molecular docking, MD simulations, and CETSA identified PI3K p85alpha as the potential binding site for naringenin, and naringenin markedly inhibited CSE-induced PI3K activity. In in vitro experiments, naringenin inhibiting MMP-9 secretion in alveolar macrophages contributed to alleviating elastin and E-cadherin damage in alveolar epithelial cells. Furthermore, naringenin effectively suppressed CSE-induced MMP-9 secretion in primary mouse alveolar macrophages and human THP-1-differentiated macrophages. Conclusions: Our findings revealed that naringenin, a potential candidate for treating smoking-induced lung injury, directly targeted PI3K p85alpha, inhibiting PI3K activity and MMP-9 expression in CSE-induced alveolar macrophages via suppressing the PI3K/AKT signaling pathway. Full article

In recent years, the role played by exosomes in lung diseases has been investigated. Exosomes have been shown to contribute to reductions in lung inflammation and pulmonary fibrosis. However, the role played by exosomes in pulmonary oxygen toxicity and the mechanism involved have not yet been reported. In the present work, we aimed to investigate the mechanism by which stem cell exosomes protect lung tissue and the potential molecular regulatory network involved. In this study, we employed single-cell RNA sequencing techniques to elucidate the unique cellular and molecular mechanisms underlying the progression of exosome therapy for pulmonary oxygen toxicity. We found changes in cell populations after exosome treatment, characterized by the expression of different molecular markers. We also integrated single-cell RNA sequencing (scRNA-seq) and bulk analysis to identify the protective effects of mesenchymal stem cell exosomes (MSC-Exos) in a mouse pulmonary oxygen toxicity (POT) model. scRNA-seq revealed dynamic shifts in the lung cellular composition after exosome treatment, including a reduction in inflammatory lymphoid cells (NK, B cells, CD8⁺ T, CD4⁺ T) and restored alveolar epithelial populations (AT1/AT2). A comprehensive gene expression analysis showed that inflammatory pathways associated with oxidative stress were significantly upregulated. In addition, our analysis of the intercellular interaction network revealed that there was a significant reduction in intercellular signal transduction in the POT group compared to the exosome-treated group. These results not only shed light on the unique cellular heterogeneity and potential pathogenesis following exosome therapy, but they also deepen our understanding of molecular pathophysiology and provide new avenues for targeted therapeutic strategies. Full article

Influenza A virus (IAV) infection causes considerable morbidity and mortality worldwide, and the secondary bacterial infection further exacerbates the severity and fatality of the initial viral infection. Mitophagy plays an important role in host resistance to pathogen infection and immune response, while its role on pulmonary epithelial cells with viral and bacterial co-infection remains unclear. The present study reveals that the secondary Staphylococcus aureus infection significantly increased the viral and bacterial loads in human lung epithelial cells (A549) during the initial H1N1 infection. Meanwhile, the secondary S. aureus infection triggered more intense mitophagy in A549 cells by activating the PINK1/Parkin signaling pathway. Notably, mitophagy could contribute to the proliferation of pathogens in A549 cells via the inhibition of cell apoptosis. Furthermore, based on an influenza A viral and secondary bacterial infected mouse model, we showed that activation of mitophagy was conducive to the proliferation of virus and bacteria in the lungs, aggravated the inflammatory damage and severe pneumonia at the same time, and eventually decreased the survival rate. The results elucidated the effect and the related molecular mechanism of mitophagy in pulmonary epithelial cells following IAV and secondary S. aureus infection for the first time, which will provide valuable information for the pathogenesis of virus/bacteria interaction and new ideas for the treatment of severe pneumonia. Full article

Background/Objectives: Chronic lower respiratory tract inflammation can result from exposure to bacterial particles, leading to the activation of the NLRP3 inflammasome pathway. These effects may cause irreversible respiratory damage, contributing to persistent lung injury and chronic obstructive pulmonary disease (COPD), as observed in long COVID or bacterial pneumonia in older adults’ patients. Given its profound impact, the NLRP3 inflammasome has emerged as a key therapeutic target for mitigating aberrant inflammatory responses. Methods: In this study, we investigated the anti-inflammatory effects of Kum Akha black rice, a functional food, on the attenuation of NLRP3 inflammasome pathway using lipopolysaccharide-induced A549 lung epithelial cells and a C57BL/6NJcl mouse model. The anthocyanin-rich fraction from Kum Akha black rice germ and bran extract (KA1-P1) was obtained using a solvent-partitioned extraction technique. Results: KA1-P1 exhibited a high anthocyanin content (74.63 ± 1.66 mg/g extract) as determined by the pH differential method. The HPLC analysis revealed cyanidin-3-O-glucoside (C3G: 45.58 ± 0.48 mg/g extract) and peonidin-3-O-glucoside (P3G: 6.92 ± 0.29 mg/g extract) as its anthocyanin’s active compounds. Additionally, KA1-P1 demonstrated strong antioxidant activity, as assessed by DPPH and ABTS assays. KA1-P1 (12.5–100 μg/mL) possessed inhibitory effects on LPS + ATP-induced A549 lung cells inflammation through the significant suppressions of NLRP3, IL-6, IL-1β, and IL-18 mRNA levels and the inhibition of cytokine secretions in a dose-dependent manner (p < 0.05). Mechanistic analysis revealed that KA1-P1 downregulated key proteins in the NLRP3 inflammasome pathway (NLRP3, ASC, pro-caspase-1, and cleaved-caspase-1). Furthermore, in vivo studies demonstrated that KA1-P1 significantly diminished LPS-induced lower respiratory inflammation in C57BL/6NJcl mice, as evidenced by the reduced bronchoalveolar lavage fluid and blood levels of inflammatory cytokines (IL-6, IL-1β, and IL-18) and diminished histopathological inflammatory lung lesions. Conclusions: Overall, our findings suggest that the anti-inflammatory properties of KA1-P1 may support its application as a functional supplement or promote the consumption of pigmented rice among the elderly to mitigate chronic lower respiratory tract inflammation mediated by the NLRP3 inflammasome pathway. Full article

Purpose: This study aimed to clarify the protective effect of astilbin (AST) on radiation-induced pulmonary fibrosis (RIPF) and explore its underlying molecular mechanism, focusing on non-coding RNAs. Methods: Mouse lung epithelial cells (MLE-12 and TC-1) and C57BL/6J mice were used to establish in vitro radiation injury models and in vivo RIPF models, respectively. Cell viability, apoptosis, the epithelial-to-mesenchymal transition (EMT), and fibrosis-related markers were assessed using cell-counting kit-8 assays, Western blotting, immunohistochemistry, and histological staining. High-throughput sequencing identified differentially expressed circRNAs. The mechanistic studies included RNA-FISH, a dual-luciferase reporter assay, an RNA immunoprecipitation (RIP) assay, and loss-of-function experiments. Results: AST significantly alleviated radiation-induced apoptosis and EMT in vitro, as well as RIPF in vivo. AST treatment reduced collagen deposition, fibrosis-related protein expression, and EMT marker changes. High-throughput sequencing revealed that AST upregulated circPRKCE, a non-coding RNA that functions through a ceRNA mechanism by binding to miR-15b-5p, thereby promoting Smad7 expression and suppressing the TGF-β/Smad7 pathway. Knockdown of circPRKCE abolished AST’s protective effects, confirming its pivotal role in mediating AST’s anti-fibrotic activity. Conclusions: This study demonstrates that Astilbin alleviates radiation-induced pulmonary fibrosis via circPRKCE targeting the TGF-β/Smad7 pathway to inhibit EMT, suggesting AST as a potential therapeutic agent for managing this severe complication of radiotherapy. Full article

Acute lung injury (ALI) is a life-threatening condition triggered by pneumonia, viral infections, or physical trauma. It manifests clinically as progressive respiratory failure and refractory hypoxemia. Using a lipopolysaccharide (LPS)-induced acute lung injury mouse model, we demonstrated that amniotic mesenchymal stem cells (AMSCs) exhibit robust reparative and anti-inflammatory properties. Our analysis encompassed inflammatory mediators; histological damage; tight junction integrity; epithelial–mesenchymal transition (EMT); and the TGF-β/Smad, TLR4/NF-κB/MAPK, pyroptosis, and apoptosis signaling pathways. Our key results demonstrated that in ALI-afflicted mice, AMSCs exhibited targeted pulmonary tropism, homing in on injured alveolar regions, where they restored the morphology and functionality of damaged tissues and organelles, re-established lung barrier function, and attenuated the aberrantly activated TLR4/NF-κB/MAPK and TGF-β/Smad pathways associated with inflammation. These coordinated mechanisms contributed to pyroptosis, apoptosis, and fibrosis suppression. In conclusion, AMSCs mitigated the inflammatory injury process in ALI mice through multiple mechanisms, thereby supporting the potential development of MSC-based therapeutic strategies. Full article

Background/Objectives: Exposure to fine particulate matter (PM_2.5) causes significant respiratory and gastrointestinal health problems. In our prior research, we identified Lactobacillus acidophilus TW01 as a promising strain for mitigating oxidative damage, enhancing wound healing in intestinal epithelial cells, and protecting bronchial cells from cigarette smoke extract. Building upon these findings, this study examines the protective effects of this strain on lung damage induced by particulate matter (PM) through the gut–lung axis in mouse models. Methods: This study evaluated the protective effects of L. acidophilus TW01 against PM_2.5-induced lung injury using two in vivo mouse models (OVA sensitization combined with PM_2.5 exposure and DSS-induced colitis). Results: L. acidophilus TW01 exhibited significant protective effects in two in-vivo models, reducing pro-inflammatory cytokines (TNF-α, IL-6, and IL-5), modulating the immune response (IgG subtypes), and improving gut barrier integrity. Importantly, L. acidophilus TW01 increased the abundance of beneficial gut bacteria (Bifidobacterium and Lactobacillus). Conclusions: These findings highlight the significant protective/therapeutic potential of L. acidophilus TW01 in mitigating the adverse health effects of PM_2.5 exposure, emphasizing the interplay between the gut and lung microbiomes in overall health. The multi-faceted protective effects of this probiotic suggest a novel, multi-pronged therapeutic strategy for addressing the widespread health consequences of air pollution. Full article

Following the COVID-19 pandemic, the prevalence of pulmonary fibrosis has increased significantly, placing patients at higher risk and presenting new therapeutic challenges. Current anti-fibrotic drugs, such as Nintedanib, can slow the decline in lung function, but their severe side effects highlight the urgent need for safer and more targeted alternatives. This study explores the anti-fibrotic potential and underlying mechanisms of an endogenous peptide (P5) derived from fibroblast growth factor 2 (FGF2), developed by our research team. Using a bleomycin-induced pulmonary fibrosis mouse model, we observed that P5 alleviated fibrosis by inhibiting collagen deposition, as confirmed by CT scans and histological staining. In TGF-β-induced cell models, P5 effectively suppressed collagen deposition and epithelial–mesenchymal transition (EMT). Transcriptome analysis highlighted pathways related to receptor binding, extracellular matrix organization, and cell adhesion, with KEGG analysis confirming FGFR/MAPK signaling inhibition as the primary mechanism underlying its anti-fibrotic effects. In summary, our study demonstrates that P5 significantly attenuates pulmonary fibrosis through the inhibition of EMT, collagen deposition, and FGFR/MAPK signaling, providing a promising therapeutic approach for fibrosis. Full article

Background: The tricellular tight junction protein angulin-1/lipolysis-stimulated lipoprotein receptor (LSR) is linked to numerous signal transduction pathways that govern gene expression, epithelial cell function, and morphogenesis. The effect of titanium dioxide (TiO₂) on LSR and asthma remains unknown. The objective of the present study was to evaluate the impact of TiO₂ on LSR expression in asthma. Methods: A TiO₂-induced animal model of asthma was established using BALB/c mice and cell lines using normal human bronchial epithelial (NHBE) lung cells and we examined LSR, RAGE, and TGFβ expression using this model. Additionally, we analyzed plasma-LSR concentrations and their correlation with clinical variables in asthma patients and control subjects. Results: The LSR concentrations in patients with asthma were lower compared to controls, and were correlated with lung function and inflammatory cell ratio. In NHBE cells treated with Derp1, LSR protein expression was reduced and changed by exposure to TiO₂, whereas TGFβ expression was increased and changed. In mouse lungs, LSR expression was significantly reduced in OVA mice and changed in OVA/TiO₂ mice. Conclusion: Circulating LSR levels were decreased and correlated with clinical variables in patients with asthma, and they were influenced by TiO₂ exposure in mice, suggesting the potential involvement of LSR in asthma pathogenesis. Full article

Background: Capsaicin is commonly used as a flavoring and a riot control agent. However, long-term exposure or high doses can cause acute lung injury in military and police personnel. The mechanisms underlying capsaicin-induced pulmonary toxicity remain unclear. Therefore, this study investigated the molecular mechanisms involved in capsaicin-induced acute lung injury using C57BL/6N mice. Methods: Through both transcriptomic and proteomic analyses of mouse lung tissue, we identified the involvement of the TNF signaling pathway in capsaicin-mediated acute lung injury. Next, we explored the role of TNF signaling in the progression of acute lung injury to identify potential therapeutic targets. In a capsaicin-induced acute lung injury mouse model and A549 cells, we assessed the therapeutic potential of the TNF-α antibody Nerelimomab. Compared with the control group, TNF-α up-regulation was observed, which correlated with increased pathological changes and elevated IL-6 (p < 0.01) and IL-18 (p < 0.01) levels, both in vivo and in vitro. Results: Flow cytometry revealed that compared to the capsaicin group, Nerelimomab treatment reduced the number of capsaicin-induced apoptotic cells (p < 0.001) and was associated with an increased Bcl-2/Bax ratio (p < 0.01) and reduced cleaved caspase 3 expression (p < 0.001). Analysis of A549 cells treated with capsaicin and Nerelimomab corroborated these results. These findings confirm the involvement of the TNF signaling pathway in capsaicin-induced acute lung injury and the apoptosis of alveolar epithelial cells. Conclusions: In conclusion, capsaicin inhalation can cause acute lung injury, and targeting the TNF signaling pathway offers a promising therapeutic strategy. Nerelimomab demonstrates significant potential in alleviating acute lung injury by inhibiting inflammatory mediator release and diminishing apoptosis. Based on transcriptomic and proteomic analyses, this study highlights the crucial role of the TNF signaling pathway in capsaicin-induced acute lung injury and supports the therapeutic efficacy of Nerelimomab in reducing epithelial apoptosis. Full article