Xuanfei Baidu decoction ameliorates bleomycin-elicited idiopathic pulmonary fibrosis in mice by regulating the lung-gut crosstalk via IFNγ/STAT1/STAT3 axis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial pneumonia, the available treatment option is limited because the etiology and pathological process are not well understood. Although gut-lung axis reported with an emerging area of host-associated microbiota exist in many chronic lung diseases, the connection between gut-lung microbiota composition with in-site inflammation in IPF development is not yet established. PURPOSE: We aimed to address the microbiota and immunity connection, and make it clear how a listed drug, Xuanfei Baidu Decoction (XFBD) affect the lung-gut crosstalk for IPF amelioration, which was previously reported for restoring disrupted lung in IPF and protecting intestinal injury. METHODS: Firstly, Micro-CT (µCT) and histopathology were used to check for pathological changes in the lungs and intestines of bleomycin (BLM)-induced IPF mice. Then, Reverse Transcription and Quantitative Real-time PCR (RT-qPCR) and Western blot (WB) assays were employed to detect the integrity of the barrier of lungs and intestines in IPF mice. Subsequently, flow cytometry and 16S rRNA sequencing were used to evaluate the immune and microbial microenvironment of the lungs and intestines. We analyzed the lung-gut microbiota crosstalk for further mechanism exploration. RESULTS: Firstly, we revealed that XFBD protected the integrity of the lung and intestinal barriers in the IPF mice, as evidenced by the up-regulation of ZO-1, Claudin-1, Occludin, and VE Cadherin protein expression. Then, we analyzed the changing microbiota and T cell in the gut-lung axis in IPF, and with XFBD, six highly relevant microenvironments were demonstrated that crossing damaged lung-gut barriers and XFBD could reverse these chaotic bacterial and immunity micro-environment, among them Akkermansia was an essential bacteria affecting the expression of systemic IFN-γ downstream STAT1/STAT3 axis was also studied. XFBD prominently up-regulated the production of IFN-γ and p-STAT1 and down-regulated p-STAT3, consequently exerting effects on the lung barrier and gut barrier. Taken together, XFBD ameliorated BLM-induced IPF mice by regulating IFNγ/STAT1/STAT3 axis. CONCLUSION: Altogether, our results revealed that XFBD improved the BLM-elicited IPF mice by regulating gut-lung crosstalk via IFN-γ/STAT1/STAT3 axis and provided a new insight of gut-lung crosstalk in IPF, especially the dynamic changes of microorganisms in the damaged lungs needed to pay more attention during IPF therapy.

Multi-omics analysis reveals the enhancing effects of Glycyrrhiza polysaccharides on the respiratory health of broilers.

This study investigated the impact of Glycyrrhiza polysaccharides (GPS) on the respiratory health of broilers. Specifically, 240 one-day-old male Arbor Acres (AA) broilers were randomly assigned to two groups: basal diet (CON) and GPS (supplemented with 150 mg/kg of Glycyrrhiza polysaccharides). When compared with the CON group, the GPS group significantly increased the broiler average daily gain, serum immunoglobulin A, immunoglobulin M, immunoglobulin G, antioxidant capacity, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and tracheal messenger RNA (mRNA) expression levels of SOD1, SOD2, and GSH-Px. The GPS group also had a reduced feed conversion ratio, reduced lung IL-1ß and IL-6 levels, and upregulated tracheal mRNA expression of Occludin, Claudin1, and Mucin-2. Additionally, the GPS group had alterations in lung microbial diversity and composition. Transcriptomic and metabolomic analyses revealed the activation of the T cell receptor (TCR) signaling pathway and linoleic acid metabolic pathway in the GPS group. Correlation analysis demonstrated significant associations between differential bacteria, genes, serum metabolites, and phenotypic indicators. In conclusion, Glycyrrhiza polysaccharide supplementation positively influenced the respiratory health of broilers by modulating the lung microbiota, activating the TCR signaling pathway, and affecting the linoleic acid metabolism pathway.

Lung microbiota: implications and interactions in chronic pulmonary diseases.

The lungs, as vital organs in the human body, continuously engage in gas exchange with the external environment. The lung microbiota, a critical component in maintaining internal homeostasis, significantly influences the onset and progression of diseases. Beneficial interactions between the host and its microbial community are essential for preserving the host's health, whereas disease development is often linked to dysbiosis or alterations in the microbial community. Evidence has demonstrated that changes in lung microbiota contribute to the development of major chronic lung diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), asthma, and lung cancer. However, in-depth mechanistic studies are constrained by the small scale of the lung microbiota and its susceptibility to environmental pollutants and other factors, leaving many questions unanswered. This review examines recent research on the lung microbiota and lung diseases, as well as methodological advancements in studying lung microbiota, summarizing the ways in which lung microbiota impacts lung diseases and introducing research methods for investigating lung microbiota.

Exploring the associations between gut microbiota composition and SARS-CoV-2 inactivated vaccine response in mice with type 2 diabetes mellitus.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is crucial for protecting vulnerable individuals, yet individuals with type 2 diabetes mellitus (T2DM) often exhibit impaired vaccine responses. Emerging evidence suggests that the composition of the host microbiota, crucial in immune regulation and development, influences vaccine efficacy. This study aimed to characterize the relationships between the SARS-CoV-2 inactivated vaccine and the host microbiota (specifically, gut and lung microbiota) of C57BL/6 mice with T2DM. Employing 16S rRNA metagenomic sequencing and ultra-high-performance liquid chromatography-mass spectrometry, we observed lower alpha diversity and distinct beta diversity in fecal microbiota before vaccination and in gut microbiota 28 days post-vaccination between T2DM mice and healthy mice. Compared with healthy mice, T2DM mice showed a higher Firmicutes/Bacteroidetes ratio 28 days post-vaccination. Significant alterations in gut microbiota composition were detected following vaccination, while lung microbiota remained unchanged. T2DM was associated with a diminished initial IgG antibody response against the spike protein, which subsequently normalized after 28 days. Notably, the initial IgG response positively correlated with fecal microbiota alpha diversity pre-vaccination. Furthermore, after 28 days, increased relative abundance of gut probiotics (Bifidobacterium and Lactobacillus) and higher levels of the gut bacterial tryptophan metabolite, indole acrylic acid, were positively associated with IgG levels. These findings suggest a potential link between vaccine efficacy and gut microbiota composition. Nonetheless, further research is warranted to elucidate the precise mechanisms underlying the impact of the gut microbiome on vaccine response. Overall, this study enhances our understanding of the intricate relationships among host microbiota, SARS-CoV-2 vaccination, and T2DM, with potential implications for improving vaccine efficacy. IMPORTANCE: Over 7 million deaths attributed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by 6 May 2024 underscore the urgent need for effective vaccination strategies. However, individuals with type 2 diabetes mellitus (T2DM) have been identified as particularly vulnerable and display compromised immune responses to vaccines. Concurrently, increasing evidence suggests that the composition and diversity of gut microbiota, crucial regulators of immune function, may influence the efficacy of vaccines. Against this backdrop, our study explores the complex interplay among SARS-CoV-2 inactivated vaccination, T2DM, and host microbiota. We discover that T2DM compromises the initial immune response to the SARS-CoV-2 inactivated vaccine, and this response is positively correlated with specific features of the gut microbiota, such as alpha diversity. We also demonstrate that the vaccination itself induces alterations in the composition and structure of the gut microbiota. These findings illuminate potential links between the gut microbiota and vaccine efficacy in individuals with T2DM, offering valuable insights that could enhance vaccine responses in this high-risk population.

The clinical impacts of lung microbiome in bronchiectasis with fixed airflow obstruction: a prospective cohort study.

BACKGROUND: Airflow obstruction is a hallmark of disease severity and prognosis in bronchiectasis. The relationship between lung microbiota, airway inflammation, and outcomes in bronchiectasis with fixed airflow obstruction (FAO) remains unclear. This study explores these interactions in bronchiectasis patients, with and without FAO, and compares them to those diagnosed with chronic obstructive pulmonary disease (COPD). METHODS: This prospective observational study in Taiwan enrolled patients with either bronchiectasis or COPD. To analyze the lung microbiome and assess inflammatory markers, bronchoalveolar lavage (BAL) samples were collected for 16S rRNA gene sequencing. The study cohort comprised 181 patients: 86 with COPD, 46 with bronchiectasis, and 49 with bronchiectasis and FAO, as confirmed by spirometry. RESULTS: Patients with bronchiectasis, with or without FAO, had similar microbiome profiles characterized by reduced alpha diversity and a predominance of Proteobacteria, distinctly different from COPD patients who exhibited more Firmicutes, greater diversity, and more commensal taxa. Furthermore, compared to COPD and bronchiectasis without FAO, bronchiectasis with FAO showed more severe disease and a higher risk of exacerbations. A significant correlation was found between the presence of Pseudomonas aeruginosa and increased airway neutrophilic inflammation such as Interleukin [IL]-1ß, IL-8, and tumor necrosis factor-alpha [TNF]-α, as well as with higher bronchiectasis severity, which might contribute to an increased risk of exacerbations. Moreover, in bronchiectasis patients with FAO, the ROSE (Radiology, Obstruction, Symptoms, and Exposure) criteria were employed to classify individuals as either ROSE (+) or ROSE (-), based on smoking history. This classification highlighted differences in clinical features, inflammatory profiles, and slight microbiome variations between ROSE (-) and ROSE (+) patients, suggesting diverse endotypes within the bronchiectasis with FAO group. CONCLUSION: Bronchiectasis patients with FAO may exhibit two distinct endotypes, as defined by ROSE criteria, characterized by greater disease severity and a lung microbiome more similar to bronchiectasis without FAO than to COPD. The significant correlation between Pseudomonas aeruginosa colonization and increased airway neutrophilic inflammation, as well as disease severity, underscores the clinical relevance of microbial patterns. This finding reinforces the potential role of these patterns in the progression and exacerbations of bronchiectasis with FAO.

Microbial signatures predictive of short-term prognosis in severe pneumonia.

Objective: This retrospective cohort study aimed to investigate the composition and diversity of lung microbiota in patients with severe pneumonia and explore its association with short-term prognosis. Methods: A total of 301 patients diagnosed with severe pneumonia underwent bronchoalveolar lavage fluid metagenomic next-generation sequencing (mNGS) testing from February 2022 to January 2024. After applying exclusion criteria, 236 patients were included in the study. Baseline demographic and clinical characteristics were compared between survival and non-survival groups. Microbial composition and diversity were analyzed using alpha and beta diversity metrics. Additionally, LEfSe analysis and machine learning methods were employed to identify key pathogenic microorganism associated with short-term mortality. Microbial interaction modes were assessed through network co-occurrence analysis. Results: The overall 28-day mortality rate was 37.7% in severe pneumonia. Non-survival patients had a higher prevalence of hypertension and exhibited higher APACHE II and SOFA scores, higher procalcitonin (PCT), and shorter hospitalization duration. Microbial α and ß diversity analysis showed no significant differences between the two groups. However, distinct species diversity patterns were observed, with the non-survival group showing a higher abundance of Acinetobacter baumannii, Klebsiella pneumoniae, and Enterococcus faecium, while the survival group had a higher prevalence of Corynebacterium striatum and Enterobacter. LEfSe analysis identified 29 distinct terms, with 10 potential markers in the non-survival group, including Pseudomonas sp. and Enterococcus durans. Machine learning models selected 16 key pathogenic bacteria, such as Klebsiella pneumoniae, significantly contributing to predicting short-term mortality. Network co-occurrence analysis revealed greater complexity in the non-survival group compared to the survival group, with differences in central genera. Conclusion: Our study highlights the potential significance of lung microbiota composition in predicting short-term prognosis in severe pneumonia patients. Differences in microbial diversity and composition, along with distinct microbial interaction modes, may contribute to variations in short-term outcomes. Further research is warranted to elucidate the clinical implications and underlying mechanisms of these findings.

Alterations and associations between lung microbiota and metabolite profiles in silica-induced lung injury.

Silicosis, caused by silica exposure, is the most widespread and deadliest occupational disease. However, effective treatments are lacking. Therefore, it is crucial to elucidate the mechanisms and targets involved in the development of silicosis. We investigated the basic processes of silicosis development and onset at different exposure durations (2 or 4 weeks) using various techniques such as histopathology, immunohistochemistry, Enzyme linked immunosorbent assay(ELISA),16 S rRNA, and untargeted metabolomics.These results indicate that exposure to silica leads to progressive damage to lung tissue with significant deterioration observed over time. Time-dependent cytokines such as the IL-4, IL-13, and IL-6 are detected in lung lavage fluid, the model group consistently exhibited elevated levels of these cytokines, indicating a persistent and worsening inflammatory response in the lungs. Meanwhile, HE and Masson results show that 4-week exposure to silica causes more obvious lung injury and pulmonary fibrosis. Besides, the model group consistently exhibited a distinct lung bacterial population, known as the Lachnospiraceae_NK4A136_group, regardless of exposure duration. However, with increasing exposure duration, specific temporal changes were observed in lung bacterial populations, including Haliangium, Allobaculum, and Sandaracinus (at 4 weeks; p < 0.05). Furthermore, our study revealed a strong correlation between the mechanism of silica-induced lung injury and three factors: oxidative stress, impaired lipid metabolism, and imbalanced amino acid metabolism. We observed a close correlation between cytokine levels, changes in lung microbiota, and metabolic disturbances during various exposure periods. These findings propose that a possible mechanism of silica-induced lung injury involves the interplay of cytokines, lung microbiota, and metabolites.

Antibiofilm activity of Prevotella species from the cystic fibrosis lung microbiota against Pseudomonas aeruginosa.

It is increasingly recognized that interspecies interactions may modulate the pathogenicity of Pseudomonas aeruginosa during chronic lung infections. Nevertheless, while the interaction between P. aeruginosa and pathogenic microorganisms co-infecting the lungs has been widely investigated, little is known about the influence of other members of the lung microbiota on the infection process. In this study, we focused on investigating the impact of Prevotella species isolated from the sputum of people with cystic fibrosis (pwCF) on biofilm formation and virulence factor production by P. aeruginosa. Screening of a representative collection of Prevotella species recovered from clinical samples showed that several members of this genus (8 out 10 isolates) were able to significantly reduce biofilm formation of P. aeruginosa PAO1, without impact on growth. Among the tested isolates, the strongest biofilm-inhibitory activity was observed for Prevotella intermedia and Prevotella nigrescens, which caused a reduction of up to 90% in the total biofilm biomass of several P. aeruginosa isolates from pwCF. In addition, a strain-specific effect of P. nigrescens on the ability of P. aeruginosa to produce proteases and pyocyanin was observed, with significant alterations in the levels of these virulence factors detected in LasR mutant strains. Overall, these results suggest that non-pathogenic bacteria from the lung microbiota may regulate pathogenicity traits of P. aeruginosa, and possibly affect the outcome of chronic lung infections.

Integrated analysis of microbiome and host transcriptome unveils correlations between lung microbiota and host immunity in bronchoalveolar lavage fluid of pneumocystis pneumonia patients.

OBJECTIVE: The lung microbiota of patients with pulmonary diseases is disrupted and impacts the immunity. The microbiological and immune landscape of the lungs in patients with pneumocystis pneumonia (PCP) remains poorly understood. METHODS: Multi-omics analysis and machine learning were performed on bronchoalveolar lavage fluid to explore interaction between the lung microbiota and host immunity in PCP. Then we constructed a diagnostic model using differential genes with LASSO regression and validated by qPCR. The immune infiltration analysis was performed to explore the landscape of lung immunity in patients with PCP. RESULTS: Patients with PCP showed a low alpha diversity of lung microbiota, accompanied by the elevated abundance of Firmicutes, and the differential expressed genes (DEGs) analysis displayed a downregulation of MAPK signaling. The MAPK10, TGFB1, and EFNA3 indicated a potential to predict PCP (AUC = 0.86). The lung immune landscape in PCP showed the lower levels of naïve CD4+ T cells and activated dendritic cells. The correlation analysis of the MAPK signaling pathway-related DEGs and the differential microorganisms at the level of phylum showed that the Firmicutes was negatively correlated with these DEGs. CONCLUSION: We profiled the characteristics of lung microbiota and immune landscape in PCP, which may contribute to elucidating the mechanism of PCP.

Host tracheal and intestinal microbiomes inhibit Coccidioides growth in vitro.

Coccidioidomycosis, also known as Valley fever, is a disease caused by the fungal pathogen Coccidioides. Unfortunately, patients are often misdiagnosed with bacterial pneumonia, leading to inappropriate antibiotic treatment. The soil Bacillus subtilis-like species exhibits antagonistic properties against Coccidioides in vitro; however, the antagonistic capabilities of host microbiota against Coccidioides are unexplored. We sought to examine the potential of the tracheal and intestinal microbiomes to inhibit the growth of Coccidioides in vitro. We hypothesized that an uninterrupted lawn of microbiota obtained from antibiotic-free mice would inhibit the growth of Coccidioides, while partial in vitro depletion through antibiotic disk diffusion assays would allow a niche for fungal growth. We observed that the microbiota grown on 2×GYE (GYE) and Columbia colistin and nalidixic acid with 5% sheep's blood agar inhibited the growth of Coccidioides, but microbiota grown on chocolate agar did not. Partial depletion of the microbiota through antibiotic disk diffusion revealed diminished inhibition and comparable growth of Coccidioides to controls. To characterize the bacteria grown and identify potential candidates contributing to the inhibition of Coccidioides, 16S rRNA sequencing was performed on tracheal and intestinal agar cultures and murine lung extracts. We found that the host bacteria likely responsible for this inhibition primarily included Lactobacillus and Staphylococcus. The results of this study demonstrate the potential of the host microbiota to inhibit the growth of Coccidioides in vitro and suggest that an altered microbiome through antibiotic treatment could negatively impact effective fungal clearance and allow a niche for fungal growth in vivo. IMPORTANCE: Coccidioidomycosis is caused by a fungal pathogen that invades the host lungs, causing respiratory distress. In 2019, 20,003 cases of Valley fever were reported to the CDC. However, this number likely vastly underrepresents the true number of Valley fever cases, as many go undetected due to poor testing strategies and a lack of diagnostic models. Valley fever is also often misdiagnosed as bacterial pneumonia, resulting in 60%-80% of patients being treated with antibiotics prior to an accurate diagnosis. Misdiagnosis contributes to a growing problem of antibiotic resistance and antibiotic-induced microbiome dysbiosis; the implications for disease outcomes are currently unknown. About 5%-10% of symptomatic Valley fever patients develop chronic pulmonary disease. Valley fever causes a significant financial burden and a reduced quality of life. Little is known regarding what factors contribute to the development of chronic infections and treatments for the disease are limited.

Silica aggravates pulmonary fibrosis through disrupting lung microbiota and amino acid metabolites.

Silicosis, recognized as a severe global public health issue, is an irreversible pulmonary fibrosis caused by the long-term inhalation of silica particles. Given the intricate pathogenesis of silicosis, there is no effective intervention measure, which poses a severe threat to public health. Our previous study reported that dysbiosis of lung microbiota is associated with the development of pulmonary fibrosis, potentially involving the lipopolysaccharides/toll-like receptor 4 pathway. Similarly, the process of pulmonary fibrosis is accompanied by alterations in metabolic pathways. This study employed a combined approach of 16S rDNA sequencing and metabolomic analysis to investigate further the role of lung microbiota in silicosis delving deeper into the potential pathogenesis of silicosis. Silica exposure can lead to dysbiosis of the lung microbiota and the occurrence of pulmonary fibrosis, which was alleviated by a combination antibiotic intervention. Additionally, significant metabolic disturbances were found in silicosis, involving 85 differential metabolites among the three groups, which are mainly focused on amino acid metabolic pathways. The changed lung metabolites showed a substantial correlation with lung microbiota. The relative abundance of Pseudomonas negatively correlated with L-Aspartic acid, L-Glutamic acid, and L-Threonine levels. These results indicate that dysbiosis in pulmonary microbiota exacerbates silica-induced fibrosis through impacts on amino acid metabolism, providing new insights into the potential mechanisms and interventions of silicosis.

Lung-Gut Microbiota and Tryptophan Metabolites Changes in Neonatal Acute Respiratory Distress Syndrome.

Purpose: Neonatal Acute Respiratory Distress Syndrome (NARDS) is a severe respiratory crisis threatening neonatal life. We aim to identify changes in the lung-gut microbiota and lung-plasma tryptophan metabolites in NARDS neonates to provide a differentiated tool and aid in finding potential therapeutic targets. Patients and Methods: Lower respiratory secretions, faeces and plasma were collected from 50 neonates including 25 NARDS patients (10 patients with mild NARDS in the NARDS_M group and 15 patients with moderate-to-severe NARDS in the NARDS_S group) and 25 control patients screened based on gestational age, postnatal age and birth weight. Lower airway secretions and feces underwent 16S rRNA gene sequencing to understand the microbial communities in the lung and gut, while lower airway secretions and plasma underwent LC-MS analysis to understand tryptophan metabolites in the lung and blood. Correlation analyses were performed by comparing differences in microbiota and tryptophan metabolites between NARDS and control, NARDS_S and NARDS_M groups. Results: Significant changes in lung and gut microbiota as well as lung and plasma tryptophan metabolites were observed in NARDS neonates compared to controls. Proteobacteria and Bacteroidota were increased in the lungs of NARDS neonates, whereas Firmicutes, Streptococcus, and Rothia were reduced. Lactobacillus in the lungs decreased in NARDS_S neonates. Indole-3-carboxaldehyde decreased in the lungs of NARDS neonates, whereas levels of 3-hydroxykynurenine, indoleacetic acid, indolelactic acid, 3-indole propionic acid, indoxyl sulfate, kynurenine, and tryptophan decreased in the lungs of the NARDS_S neonates. Altered microbiota was significantly related to tryptophan metabolites, with changes in lung microbiota and tryptophan metabolites having better differentiated ability for NARDS diagnosis and grading compared to gut and plasma. Conclusion: Significant changes occurred in the lung-gut microbiota and lung-plasma tryptophan metabolites of NARDS neonates. Alterations in lung microbiota and tryptophan metabolites were better discriminatory for the diagnosis and grading of NARDS.

Analyzing the characteristics of respiratory microbiota after the placement of an airway stent for malignant central airway obstruction.

Malignant central airway stenosis is treated with airway stent placement, but post-placement microbial characteristics remain unclear. We studied microbial features in 60 patients post-stent placement, focusing on changes during granulation tissue proliferation. Samples were collected before stent (N = 29), after stent on day 3 (N = 20), and after granulation tissue formation (AS-GTF, N = 43). Metagenomic sequencing showed significant respiratory tract microbiota changes with granulation tissue. The microbiota composition, dominated by Actinobacteria, Firmicutes, and Proteobacteria, was similar among the groups. At the species level, the AS-GTF group exhibited significant differences, with Peptostreptococcus stomatis and Achromobacter xylosoxidans enriched. Analysis based on tracheoesophageal fistula presence identified Tannerella forsythia and Stenotrophomonas maltophilia as the main differential species, enriched in the fistula subgroup. Viral and fungal detection showed Human gammaherpesvirus 4 and Candida albicans as the main species, respectively. These findings highlight microbiota changes after stent placement, potentially associated with granulation tissue proliferation, informing stent placement therapy and anti-infective treatment optimization. IMPORTANCE: Malignant central airway stenosis is a life-threatening condition that can be effectively treated with airway stent placement. However, despite its clinical importance, the microbial characteristics of the respiratory tract following stent insertion remain poorly understood. This study addresses this gap by investigating the microbial features in patients with malignant central airway stenosis after stent placement, with a specific focus on microbial changes during granulation tissue proliferation. The findings reveal significant alterations in the diversity and structure of the respiratory tract microbiota following the placement of malignant central airway stents. Notably, certain bacterial species, including Peptostreptococcus stomatis and Achromobacter xylosoxidans, exhibit distinct patterns in the after-stent granulation tissue formation group. Additionally, the presence of tracheoesophageal fistula further influences the microbial composition. These insights provide valuable references for optimizing stent placement therapy and enhancing clinical anti-infective strategies.

Gut-Lung Microbiota Characterization in Patients with Non-Small Cell Lung Carcinoma and COVID-19 Coinfection.

BACKGROUND: Non-small cell lung cancer (NSCLC) patients with COVID-19 have an excessive chance of morbidity and mortality. The fecal-nasopharyngeal microbiota compositions of NSCLC patients were assessed in this study. METHODS: In total, 234 samples were collected from 17 NSCLC patients infected with COVID-19, 20 NSCLC patients without confirmed COVID-19, 40 non NSCLC patients with COVID-19, and 40 healthy individuals. RESULTS: In lung microbiota, the abundance of Streptococcus spp. in NSCLC patients with confirmed COVID-19 was significantly higher than the two control groups. Pseudomonas aeruginosa and Staphylococcus aureus were listed as the most frequent pulmonary bacterial groups that colonized COVID-19 patients. In fecal specimens, the numbers of Bacteroidetes, Firmicutes, and Actinobacteria phyla were significantly higher amongst NSCLC patients with COVID-19. NSCLC patients infected with COVID-19 showed lower levels of Lactobacillus spp., Akkermansia muciniphila, and Bifidobacterium spp. The counts of Streptococcus spp., in NSCLC patients with COVID-19 were significantly higher than those of healthy individuals (8.49±0.70 log CFU/g wet feces vs 8.49±0.70 log CFU/g wet feces). Prevotella spp. were enriched in the gut and respiratory tracts of COVID-19 patient groups. The unbiased analysis showed an increment in Enterococcus spp., Streptococcus spp., and Prevotella spp. CONCLUSION: Eventually, it was found that compared to control groups, COVID-19 patients with NSCLC showed diminished gut bacteria diversity and increase in Lactobacillus spp., A. muciniphila, and Bifidobacterium spp. The overgrowth of Enterococcus spp., Streptococcus spp., and Prevotella spp. could be potential predictive biomarkers in the gut-lung axis of NSCLC patients with COVID-19.

Stenotrophomonas maltophilia contributes to smoking-related emphysema through IRF1-triggered PANoptosis of alveolar epithelial cells.

Cigarette smoke (CS), the main source of indoor air pollution and the primary risk factor for respiratory diseases, contains chemicals that can perturb microbiota through antibiotic effects. Although smoking induces a disturbance of microbiota in the lower respiratory tract, whether and how it contributes to initiation or promotion of emphysema are not well clarified. Here, we demonstrated an aberrant microbiome in lung tissue of patients with smoking-related COPD. We found that Stenotrophomonas maltophilia (S. maltophilia) was expanded in lung tissue of patients with smoking-related COPD. We revealed that S. maltophilia drives PANoptosis in alveolar epithelial cells and represses formation of alveolar organoids through IRF1 (interferon regulatory factor 1). Mechanistically, IRF1 accelerated transcription of ZBP1 (Z-DNA Binding Protein 1) in S. maltophilia-infected alveolar epithelial cells. Elevated ZBP1 served as a component of the PANoptosome, which triggered PANoptosis in these cells. By using of alveolar organoids infected by S. maltophilia, we found that targeting of IRF1 mitigated S. maltophilia-induced injury of these organoids. Moreover, the expansion of S. maltophilia and the expression of IRF1 negatively correlated with the progression of emphysema. Thus, the present study provides insights into the mechanism of lung dysbiosis in smoking-related COPD, and presents a potential target for mitigation of COPD progression.

Exploring the Role of Gut-Lung Interactions in COPD Pathogenesis: A Comprehensive Review on Microbiota Characteristics and Inflammation Modulation.

Chronic obstructive pulmonary disease (COPD) is a paramount contributor to global morbidity and mortality. Over the past decade, the concept of the "gut-lung axis" has emerged, offering a lens through which to examine the intricate interplay between the host, microbiome, and respiratory diseases, including COPD. An expanding body of evidence underscores that the composition of both the gastrointestinal and respiratory microbiome deviates in COPD patients compared to healthy individuals, leading to distinct host immune responses and clinical manifestations. The objective of this review is to provide a concise overview of the role both gut and respiratory microbiome play in the development of COPD. This was accomplished by compiling current literature on the microbiome profile in stable and exacerbated cases of COPD, as well as exploring the biological mechanisms through a discussion of relevant experiments conducted on murine models. Hallmark characteristics of the microbial profile in COPD encompass reduced Prevotella species in the respiratory microbiome, culminating in a loss of anti-inflammatory protection, and diminished Bacteroidetes in the gut microbiome, leading to a decrease in protective short-chain fatty acids. The proliferation of Proteobacteria, particularly the Haemophilus species, Moraxellaspecies, and Pseudomonas species contribute to COPD pathologies via recognition of proinflammatory lipopolysaccharide via Toll-like receptors. As a consequence, deteriorated pulmonary function, enhanced severity, increased onset of exacerbations, and elevated mortality were observed.

First Exploration of the Altered Microbial Gut-Lung Axis in the Pathogenesis of Human Refractory Chronic Cough.

PURPOSE: Cough represents a natural mechanism that plays an important defensive role in the respiratory tract, but in some conditions, it may become persistent, nonproductive, and harmful. In general, refractory chronic cough (RCC) occurs in about 20% of individuals; hence, we aimed to assess the presence of altered gut-lung communication in RCC patients through a compositional and functional characterization of both gut (GM) and oral microbiota (OM). METHODS: 16S rRNA sequencing was used to characterize both GM and OM composition of RCC patients and healthy controls (HC). PICRUST2 assessed functional changes in microbial communities while gas chromatography was used to evaluate fecal short-chain fatty acid levels and serum-free fatty acid (FFA) abundances. RESULTS: In comparison with HC, RCC patients reported increased saliva alpha-diversity and statistically significant beta-diversity in both GM and OM. Also, a, respectively, significant increased or reduced Firmicutes/Bacteroidota ratio in stool and saliva samples of RCC patients has been shown, in addition to a modification of the abundances of several taxa in both GM and OM. Moreover, a potential fecal over-expression of lipopolysaccharide biosynthesis and lipoic acid metabolism pathways and several differences in serum FFA levels have been reported in RCC patients than in HC. CONCLUSION: Since differences in both GM and OM of RCC patients have been documented, these findings could provide new information about RCC pathogenesis and also pave the way for the development of novel nutritional or pharmacological interventions for the management of RCC through the restoration of eubiotic gut-lung communication.

P. gingivalis alters lung microbiota and aggravates disease severity of COPD rats by up-regulating Hsp90α/MLKL.

Background: Epidemiological evidence has confirmed that periodontitis is an essential and independent risk factor of chronic obstructive pulmonary disease (COPD). Porphyromonas gingivalis, a major pathogen implicated in periodontitis, may make a vital contribution to COPD progression. However, the specific effects and molecular mechanism of the link between P. gingivalis and COPD are not clear. Methods and Results: A COPD rat model was constructed by smoke exposure combined intratracheal instillation of E. coli-LPS, then P. gingivalis was introduced into the oral cavity of COPD rats. This research observed that lower lung function, more severe alveolar damage and inflammation occurred in COPD rats with P. gingivalis group. Meanwhile, P. gingivalis/gingipains could colonize the lung tissues and be enriched in bronchoalveolar lavage fluid (BALF) of COPD rats with P. gingivalis group, along with alterations in lung microbiota. Proteomic analysis suggested that Hsp90α/MLKL-meditated necroptosis pathway was up-regulated in P. gingivalis-induced COPD aggravation, the detection of Hsp90α and MLKL in serum and lung tissue verified that Hsp90α/MLKL was up-regulated. Conclusion: These results indicate that P. gingivalis could emigrate into the lungs, alter lung microbiota and lead to aggravation of COPD, which Hsp90α/MLKL might participate in.

Development of inhalation powders containing lactic acid bacteria with antimicrobial activity against Pseudomonas aeruginosa.

OBJECTIVES: The aim of the project was to develop and characterise powders containing a probiotic (Lactiplantibacillus plantarum [Lpb. plantarum], Lacticaseibacillus rhamnosus, or Lactobacillus acidophilus) to be administered to the lung for the containment of pathogen growth in patients with lung infections. METHODS: The optimised spray drying process for the powder manufacturing was able to preserve viability of the bacteria, which decreased of only one log unit and was maintained up to 30 days. RESULTS: Probiotic powders showed a high respirability (42%-50% of particles had a size < 5 µm) suitable for lung deposition and were proven safe on A549 and Calu-3 cells up to a concentration of 107 colony-forming units/mL. The Lpb. plantarum adhesion to both cell lines tested was at least 10%. Surprisingly, Lpb. plantarum powder was bactericidal at a concentration of 106 colony-forming units/mL on P. aeruginosa, whereas the other two strains were bacteriostatic. CONCLUSION: This work represents a promising starting point to consider a probiotic inhalation powder a value in keeping the growth of pathogenic microflora in check during the antibiotic inhalation therapy suspension in cystic fibrosis treatment regimen. This approach could also be advantageous for interfering competitively with pathogenic bacteria and promoting the restoration of the healthy microbiota.

Investigation of the mechanism of silica-induced pulmonary fibrosis: The role of lung microbiota dysbiosis and the LPS/TLR4 signaling pathway.

The widespread manufacture of silica and its extensive use, and potential release of silica into the environment pose a serious human health hazard. Silicosis, a severe global public health issue, is caused by exposure to silica, leading to persistent inflammation and fibrosis of the lungs. The underlying pathogenic mechanisms of silicosis remain elusive. Lung microbiota dysbiosis is associated with the development of inflammation and fibrosis. However, limited information is currently available regarding the role of lung microbiota in silicosis. The study therefore is designed to conduct a comprehensive analysis of the role of lung microbiota dysbiosis and establish a basis for future investigations into the potential mechanisms underlying silicosis. Here, the pathological and biochemical parameters were used to systematically assessed the degree of inflammation and fibrosis following silica exposure and treatment with combined antibiotics. The underlying mechanisms were studied via integrative multi-omics analyses of the transcriptome and microbiome. Analysis of 16S ribosomal DNA revealed dysbiosis of the microbial community in silicosis, characterized by a predominance of gram-negative bacteria. Exposure to silica has been shown to trigger lung inflammation and fibrosis, leading to an increased concentration of lipopolysaccharides in the bronchoalveolar lavage fluid. Furthermore, Toll-like receptor 4 was identified as a key molecule in the lung microbiota dysbiosis associated with silica-induced lung fibrosis. All of these outcomes can be partially controlled through combined antibiotic administration. The study findings demonstrate that the dysbiosis of lung microbiota enhances silica-induced fibrosis associated with the lipopolysaccharides/Toll-like receptor 4 pathway and provided a promising target for therapeutic intervention of silicosis.