A curious connection: Teasing apart the link between gut microbes and lung disease

Whole genome comparisons reveal gut-to-lung translocation of Escherichia coli and Burkholderia cenocepacia in two cases of ventilator-associated pneumonia in ICU patients

BACKGROUND

Identifying the sources of pathogenic bacteria causing ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients is crucial for developing effective prevention and treatment strategies. However, the scarcity of reported cases with confirmed sources limits the ability to evaluate and manage VAP, which remains a major challenge for healthcare systems globally.

METHODS

Pathogens were isolated from endotracheal aspirate (ETA) samples of VAP patients using conventional culture techniques. Whole-genome comparisons, based on average nucleotide identity (ANI), were performed to identify genetically identical strains by comparing pulmonary isolate genomes with gut metagenome-derived bacterial genomes. Mouse models of pneumonia and colitis were used to validate the translocation of pathogenic bacteria from the gut to the lungs. Metagenomic analysis was performed to characterize the gut microbiome and resistome.

RESULTS

Pathogenic isolates were obtained from the ETA samples of seven VAP patients, with one isolate per sample. Among these, Escherichia coli (Ec1) and Burkholderia cenocepacia (Bc1) from two patients were genetically identical to strains in their respective gut microbiota, with ANI values above 99%, indicating gut-to-lung translocation. The Ec1 strain demonstrated increased resistance to cefazolin while remaining susceptible to gentamicin, amikacin, and kanamycin, compared to previously reported pneumonia-associated E. coli strains. The Bc1 strain showed elevated resistance to macrolides, chloramphenicols, and tetracyclines relative to pneumonia-associated B. cenocepacia strains. Metagenomic analysis revealed a highly individualized gut microbiota composition among VAP patients. Notably, the translocated bacteria were not dominant within their gut microbiota. Additionally, these patients showed a marked increase in the total abundance of antibiotic resistance genes (ARGs) in their gut microbiota. The translocation ability of the Ec1 strain was validated in a mouse pneumonia model, where it caused more severe lung damage. Furthermore, elevated levels of Escherichia-Shigella were detected in the lung tissues of colitis mice, suggesting that gut-to-lung bacterial translocation may occur in a severely inflamed host, potentially leading to pneumonia.

CONCLUSIONS

This study demonstrates the gut-to-lung translocation of E. coli and B. cenocepacia, highlighting their role in the development and progression of VAP in ICU patients. These findings provide valuable insights for implementing targeted prevention and treatment strategies for VAP in ICU settings.

Parabacteroides distasonis promotes CXCL9 secretion of tumor-associated macrophages and enhances CD8+T cell activity to trigger anti-tumor immunity against anti-PD-1 treatment in non-small cell lung cancer mice

BACKGROUND

Parabacteroides distasonis (P. distasonis) could regulate inflammatory markers, promote intestinal barrier integrity, and block tumor formation in colon. However, the regulatory effect of P. distasonis on non-small cell lung cancer (NSCLC) remains unknown. This study aimed to investigate the regulatory effect of P. distasonis on NSCLC and its impact on tumor immunity.

METHODS

We first established a mouse model of Lewis lung cancer, and administered P. distasonis and intrabitoneal injection of anti-mouse PD-1 monoclonal antibody to assess the impact of P. distasonis on tumor immunity, and mouse intestinal barrier. Then, we explored the effect of P. distasonis on CD8+T cells and CXCL9 secretion mediated by tumor-associated macrophages (TAM). We used the TLR1/2 complex inhibitor CPT22 to evaluate its effect on macrophage activation. Finally, we explored the effect of P. distasonis on CD8+T cells and CXCL9 secreted by TAM in vivo.

RESULTS

In vivo, P. distasonis enhanced anti-tumor effects of anti-PD-1 in NSCLC mice, improved intestinal barrier integrity, recruited macrophages, and promoted M1 polarization. In vitro, CD86 and iNOS levels in BMDM were elevated and CD206 and Arg1 levels were suppressed in membrane fraction of P. distasonis (PdMb) group in comparison to Control group. With additional CPT22 pre-treatment, the levels of CD86 and iNOS in BMDM were reduced, and the levels of CD206 and Arg1 were increased. Compared to PBS group, P. distasonis group exhibited higher proportion of CD8+T cells in tumor tissues, along with increased positive proportion of GZMB and IFN-γ in CD8+T cells. Additionally, in comparison to Control group, PdMb group showed an elevated proportion of GZMB+T and IFN-γ+T cells within CD8+T cells, and secretion of IFN-γ, TNF-α, perforin, and GZMB in CD8+T cell supernatant increased. Moreover, the proportion of CXCL9+F4/80+ macrophages in tumor tissues was higher in P. distasonis group compared to PBS group. In comparison to Control group, CXCL9 protein level in BMDM and CXCL9 secretion level in BMDM supernatant were increased in PdMb group. Finally, P. distasonis enhanced CD8+T cell activity by secreting CXCL9 from macrophages in vivo.

CONCLUSIONS

P. distasonis promoted CXCL9 secretion of TAM and enhanced CD8+T cell activity to trigger anti-tumor immunity against anti-PD-1 treatment in NSCLC mice.

Ligilactobacillus salivarius regulating translocation of core bacteria to enrich mouse intrinsic microbiota of heart and liver in defense of heat stress

The aim of this study was to elucidate the intrinsic microbiota residing in the heart and liver, which was enriched with Ligilactobacillus salivarius supplementation and its roles in defending anti-oxidation of heat stress. The specific pathogen free (SPF) mice were employed to perform the study. Genomic sequencing showed that the intrinsic microbes in the heart and liver of SPF mice, which were primarily of the genera Burkholderia and Ralstonia, functioned in organic metabolism, environmental information processing, cellular processes, and genetic information processing. Lactobacillus sp. were found in the liver but not in the heart. The heart had a lower bacterial abundance than the liver. A culturomic assay of the heart flushing liquid indicated that the dominant species of bacteria were Ralstonia pickettii, Ralstonia sp._3PA37C10, Ralstonia insidiosa, Burkholderia lata, unclassified _g_ Ralstonia, and unclassified _p_ Pseudomonadota. Intrinsic bacteria exist in the heart due to their inhibitory action against pathogenic Escherichia coli. After, the mice were supplemented with Ligilactobacillus salivarius to optimize the microbiota levels. The dominant bacterial phyla in the liver and heart were Bacillota, Bacteroidota, Pseudomonadota, Thermodesulfobacteriota, andActinomycetota, which comprised 98.2% of total bacteria. The genus Lactobacillus was also abundant. Core bacteria such as Lactobacillus reuteri are translocated from the intestine to the heart and liver. The enriched bacterial composition up-regulated anti-oxidation capacities in the heart and liver. The levels of reactive oxygen species and superoxide dismutase (SOD) were significantly improved compared to those in control (P < 0.01). In conclusion, intrinsic bacteria present in the heart and liver alleviate infection by pathogens, environmental and genetic information processing, and cellular processes during heat stress exposure. Diet with Ligilactobacillus salivarius supplementation regulated the translocation of core bacteria to the heart and liver, improved bacterial composition, and induced a higher anti-oxidative capacity under heat stress.

Integrated network pharmacological analysis and multi-omics techniques to reveal the mechanism of polydatin in the treatment of silicosis via gut-lung axis

Silicosis is a pulmonary disease characterized by inflammation and progressive fibrosis. Previous studies have shown that polydatin (PD) has potential biological activity in key signaling pathways regulating inflammation and apoptosis. To investigate the effect of PD on rats with silicosis, this study used network pharmacology and molecular docking methods to determine the target of PD treatment for silicosis. The therapeutic effect of PD on silicosis was confirmed by measuring the lung injury score, hydroxyproline content, and mRNA expression levels of key targets. In addition, metagenomic sequencing and gas chromatography-mass spectrometry were used to determine the gut microbiota composition and targeted metabolomics analysis, respectively. The results showed that PD could inhibit the expression of inflammation-related indexes and apoptosis-related indexes at protein and mRNA levels. PD also regulates the diversity of the intestinal flora and the content of short-chain fatty acids. In conclusion, the current data suggest that PD has a protective effect against silica-induced lung injury and plays a protective role in regulating intestinal flora diversity and short-chain fatty acid levels through the gut-lung axis.

Advancements related to probiotics for preventing and treating recurrent respiratory tract infections in children

Recurrent respiratory tract infections (RRTIs) are a common condition in pediatrics and significantly impact children's quality of life; however, their pathogenesis and contributing factors are not yet fully elucidated. Probiotics have recently emerged as promising agents for modulating intestinal microecology and have gained considerable attention in clinical research on preventing and treating RRTIs in children. This article provides an initial overview of the concept, classification, and mechanisms underlying probiotics. It emphasizes their beneficial effects on respiratory health by modulating intestinal microbial equilibrium, augmenting immune system functionality, and attenuating inflammatory responses. Subsequently, we examine existing research regarding the use of probiotics in pediatric RRTIs. Numerous clinical trials have unequivocally demonstrated that supplementing with probiotics can significantly reduce both the frequency and severity of RRTIs in children while also simultaneously decreasing antibiotic usage. However, there are ongoing controversies and challenges in current research concerning the influence of probiotic type, dosage, duration of use, and other factors on efficacy. Furthermore, variations have been observed across different studies. Additionally, it is crucial to further evaluate the safety and potential long-term side effects associated with probiotic use in children with RRTIs. In conclusion, we propose future research directions including conducting more high-quality randomized controlled trials to optimize application strategies for probiotics alongside other treatments while considering variations based on age and health conditions among pediatric populations. Finally, in summary although probiotics exhibit promising benefits in preventing and treating RRTIs in children; additional studies are necessary to refine their application strategies ensuring both safety and effectiveness.

The Tan-Re-Qing Capsule mitigates acute lung injury by suppressing the NLRP3 inflammasome and MAPK/NF-κB signaling pathways

OBJECTIVE

The Tan-Re-Qing Capsule (TRQC), a traditional Chinese medicine (TCM) preparation, has been historically utilized in treating acute lung injury (ALI) and COVID-19-induced pulmonary diseases. This study aimed to explore the effect and underlying mechanisms of TRQC in lipopolysaccharide (LPS)-induced ALI models.

METHODS

The changes of acute lung injury and inflammatory response were observed after TRQC treatment of the LPS-induced ALI mouse model. Based on active compounds in TRQC and network pharmacology analysis, potential targeting signals were identified. The effects of TRQC on signaling in LPS-stimulated BMDMs were investigated. Additionally, the defecatory status of mice and the mechanism of Cl- secretion in HBE cells and T84 colonic epithelial cells were examined.

RESULTS

TRQC exhibited a notable amelioration of inflammatory injuries in ALI mice. Utilizing a systems-pharmacology approach based on active chemical compounds, TRQC was found to regulate inflammation-related pathways, including NF-κB, NOD-like signaling, and MAPK signaling. In vitro experiments demonstrated that TRQC effectively suppressed LPS-induced activation of macrophages and the assembly of the NLRP3 inflammasome induced by LPS and Nigericin. These effects were attributed to the suppression of NF-κB and NOD-like signaling pathways. Furthermore, TRQC blocked MAPK signaling, thereby mitigating the inhibitory effects of LPS and Nigericin on Ca2+-dependent Cl- efflux across colonic epithelial cells. This mechanism generated a cathartic effect, potentially aiding in the removal of harmful substances and pathogenic bacteria.

CONCLUSION

Our study demonstrates that TRQC significantly mitigates ALI by effectively suppressing the NLRP3 inflammasome and MAPK/NF-κB signaling pathways. These findings suggest that TRQC could serve as a promising therapeutic candidate for inflammatory lung diseases, offering a novel approach to managing conditions like ALI and potentially extending to other inflammatory diseases.

Bidirectional association between pneumonia and intestinal infection: an analysis of the MIMIC-IV database

The purpose is to analyze the prevalence of intestinal infection in patients with pneumonia in intensive care units (ICU) and the impact of intestinal infection on the prognosis of patients with pneumonia, so as to explore the bidirectional association between pneumonia and intestinal infection. The study aims to investigate the correlation between the occurrence of pneumonia and intestinal infection among patients in the ICU, utilizing the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, as well as the impact of intestinal infection on the prognosis of pneumonia patients. The enrolled patients were first divided into pneumonia group and non-pneumonia group, and the primary outcome was that patients developed intestinal infection. Multivariate logistic regression was used to elucidate the association between pneumonia and the prevalence of intestinal infection, and propensity score matching (PSM) and inverse probability of treatment weighing (IPTW) were used to validate our findings. We then divided patients with pneumonia into two groups according to whether they were complicated by intestinal infection, and analyzed the effect of intestinal infection on 28-day mortality, length of ICU stay, and length of hospital stay in patients with pneumonia. This study included 50,920 patients, of which 7493 were diagnosed with pneumonia. Compared with non-pneumonia patients, the incidence of intestinal infection in pneumonia patients was significantly increased [OR 1.58 (95% CI 1.34-1.85; P < 0.001)]. Cox proportional hazards regression model showed no significant effect of co-infection on 28-day mortality in patients with pneumonia (P = 0.223). Patients in the intestinal infection group exhibited a longer length stay in ICU and hospital than those without intestinal infection (P < 0.001). In the ICU, patients with pneumonia were more likely linked to intestinal infection. In addition, the presence of concurrent intestinal infections can prolong both ICU and hospital stays for pneumonia patients.

Short-chain fatty acids play a key role in antibody response to SARS-CoV-2 infection in people living with HIV

High SARS-CoV-2-specific antibody levels can protect against SARS-CoV-2 reinfection. The gut microbiome can affect a host's immune response. However, its role in the antibody response to SARS-CoV-2 in people living with HIV (PLWH) remains poorly understood. Here, we categorised PLWH and healthy individuals into high- and low-antibody-response groups. Shotgun metagenomic sequencing and targeted metabolomic assays were used to investigate the differences in the gut microbiome and metabolic functions between the high- and low-antibody-response groups. PLWH demonstrated a higher abundance of short-chain fatty acid (SCFA)-producing species, accompanied by high serum levels of several SCFAs, in the high-antibody-response group than in the low-antibody-response group. In contrast, healthy individuals demonstrated higher enrichment of pilus-bearing bacterial species, with flagella-expressing genes, in the high-antibody-response group than in the low-antibody-response group. Therefore, gut-microbiota-derived SCFAs play a key role in antibody responses in PLWH but not in healthy individuals. Our results afford a novel understanding of how the gut microbiome and its metabolites are associated with host immunity. Moreover, they may facilitate the exploration of modalities to prevent SARS-CoV-2 reinfection through various gut-microbiota-targeted interventions tailored to different populations.

Gut microbiota in post-acute COVID-19 syndrome: not the end of the story

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has led to major global health concern. However, the focus on immediate effects was assumed as the tip of iceberg due to the symptoms following acute infection, which was defined as post-acute COVID-19 syndrome (PACS). Gut microbiota alterations even after disease resolution and the gastrointestinal symptoms are the key features of PACS. Gut microbiota and derived metabolites disorders may play a crucial role in inflammatory and immune response after SARS-CoV-2 infection through the gut-lung axis. Diet is one of the modifiable factors closely related to gut microbiota and COVID-19. In this review, we described the reciprocal crosstalk between gut and lung, highlighting the participation of diet and gut microbiota in and after COVID-19 by destroying the gut barrier, perturbing the metabolism and regulating the immune system. Therefore, bolstering beneficial species by dietary supplements, probiotics or prebiotics and fecal microbiota transplantation (FMT) may be a novel avenue for COVID-19 and PACS prevention. This review provides a better understanding of the association between gut microbiota and the long-term consequences of COVID-19, which indicates modulating gut dysbiosis may be a potentiality for addressing this multifaceted condition.

Exposure to toluene diisocyanate induces dysbiosis of gut-lung homeostasis: Involvement of gut microbiota

Toluene diisocyanate (TDI) is a major industrial compound that induces occupational asthma with steroid-resistant properties. Recent studies suggest that the gastrointestinal tract may be an effective target for the treatment of respiratory diseases. However, the alterations of the gut-lung axis in TDI-induced asthma remain unexplored. Therefore, in this study, a model of stable occupational asthma caused by TDI exposure was established to detect the alteration of the gut-lung axis. Exposure to TDI resulted in dysbiosis of the gut microbiome, with significant decreases in Barnesiella_intestinihominis, Faecalicoccus_pleomorphus, Lactobacillus_apodemi, and Lactobacillus_intestinalis, but increases in Alistipes_shahii and Odoribacter_laneus. The largest change in abundance was in Barnesiella_intestinihominis, which decreased from 12.14 per cent to 6.18 per cent. The histopathological abnormalities, including shorter length of intestinal villi, thinner thickness of muscularis, reduced number of goblet cells and inflammatory cell infiltration, were found in TDI-treated mice compared to control mice. In addition, increased permeability (evidenced by significantly reduced levels of ZO-1, Occludin and Claudin-1) and activation of TLR4/NF-κB signaling were observed in the intestine of these TDI-exposed mice. Concurrently, exposure to TDI resulted in airway hyperresponsiveness, overt cytokine production (e.g., IL-4, IL-5, IL-13, IL-25, and IL-33), and elevated IgE level within the respiratory tract. The expression of tight junction proteins is reduced and TLR4/NF-κB signaling is activated in the lung following TDI treatment. In addition, correlation analyses showed that changes in the gut microbiota were correlated with TDI exposure-induced airway inflammation. In conclusion, the present study suggests that the immune gut-lung axis may be involved in the development of TDI-induced asthma, which may have implications for potential interventions against steroid-resistant asthma.

Transmission of blaNDM in Enterobacteriaceae among animals, food and human

Despite carbapenems not being used in animals, carbapenem-resistant Enterobacterales (CRE), particularly New Delhi metallo-β-lactamase-producing CRE (NDM-CRE), are prevalent in livestock. Concurrently, the incidence of human infections caused by NDM-CRE is rising, particularly in children. Although a positive association between livestock production and human NDM-CRE infections at the national level was identified, the evidence of direct transmission of NDM originating from livestock to humans remains largely unknown. Here, we conducted a cross-sectional study in Chengdu, Sichuan Province, to examine the prevalence of NDM-CRE in chickens and pigs along the breeding-slaughtering-retail chains, in pork in cafeterias of schools, and in colonizations and infections from children's hospital and examined the correlation of NDM-CRE among animals, foods and humans. Overall, the blaNDM increases gradually along the chicken and pig breeding (4.70%/2.0%) -slaughtering (7.60%/22.40%) -retail (65.56%/34.26%) chains. The slaughterhouse has become a hotspot for cross-contamination and amplifier of blaNDM. Notably, 63.11% of pork from the school cafeteria was positive for blaNDM. The prevalence of blaNDM in intestinal and infection samples from children's hospitals was 21.68% and 19.80%, respectively. whole genome sequencing (WGS) analysis revealed the sporadic, not large-scale, clonal spread of NDM-CRE along the chicken and pig breeding-slaughtering-retail chain, with further spreading via IncX3-blaNDM plasmid within each stage of whole chains. Clonal transmission of NDM-CRE is predominant in children's hospitals. The IncX3-blaNDM plasmid was highly prevalent among animals and humans and accounted for 57.7% of Escherichia coli and 91.3% of Klebsiella pneumoniae. Attention should be directed towards the IncX3 plasmid to control the transmission of blaNDM between animals and humans.

Protective effect of Shenqi Wenfei Formula against lipopolysaccharide/cigarette smoke-induced COPD in Rat based on gut microbiota and network pharmacology analysis

Introduction

The incidence of chronic obstructive pulmonary disease (COPD) appears to be increasing and evidence suggests that the intestinal flora may play a causative role in its development. Previous studies found that the Shenqi Wenfei Formula (SQWF) can regulate pyroptosis via the NLRP3/GSDMD pathway, thereby reducing the inflammatory response in the lungs of COPD model rats. However, there is no information on whether the drug's effects are associated with intestinal flora. Therefore, this study investigates whether the effects of SQWF are mediated through the regulation of intestinal flora, aiming to elucidate the underlying mechanisms of its therapeutic impact on COPD.

Methods

COPD was induced in rats using lipopolysaccharide and cigarette smoke, followed by intragastric administration of SQWF or physiological saline The targets of SQWF, associated signaling pathways, and key bacterial groups were investigated using 16S rRNA sequencing, network pharmacology, and bioinformatics techniques. The prediction results were validated using quantitative reverse transcription PCR, western blotting, and immunofluorescence, among other methods.

Results

SQWF treatment was found to alleviate COPD in model rats. Treatment was also observed to restore the balance of the intestinal flora in the rats, especially by reducing the abundance of g_Parabacteroides. Bioinformatics predictions identified g_Parabacteroides metabolites, RelA, HDAC1, and enriched neutrophil extracellular trap formation pathways as core targets of SQWF in COPD. qRT-PCR and Western blotting results showed that SQWF treatment reduced ReLA and HDAC1 mRNA and protein expression, along with decreased myeloperoxidase and neutrophil elastase levels in the nucleus.

Conclusion

Treatment with SQWF was found to restore the imbalance of intestinal g_Parabacteroides in COPD and also regulate the expression of the ReLA and HDAC1 genes, thereby reducing pulmonary neutrophil extracellular traps and alleviating lung inflammation.

Sodium propionate ameliorates lipopolysaccharide-induced acute respiratory distress syndrome in rats via the PI3K/AKT/mTOR signaling pathway

Acute respiratory distress syndrome (ARDS) is a severe lung disease characterized by significant hypoxemia, which impairs the oxygen supply necessary for optimal lung function. This study aimed to investigate the effects of sodium propionate (SP), the primary end product of intestinal flora fermentation of dietary fiber, on lipopolysaccharide (LPS)-induced ARDS in rats. The rats were treated with SP, after which the lung wet/dry ratio, arterial partial oxygen pressure (PaO2), levels of pro- and anti-inflammatory cytokines, tight junction proteins ZO-1 and Occludin, as well as LC3 and phosphorylated PI3K (p-PI3K)/p-AKT/p-mTOR protein levels, were measured. Additionally, histopathological analysis was conducted. The results indicated that SP effectively alleviated arterial hypoxemia in rats and mitigated the pathological damage to both intestinal and lung tissues caused by LPS. Notably, SP significantly reduced the levels of inflammatory factors TNF-α and IL-6 in the blood and bronchoalveolar lavage fluid (BALF) of ARDS rats, while increasing the concentration of the anti-inflammatory factor IL-10. Furthermore, SP inhibited the activation of the PI3K/AKT/mTOR signaling pathway and enhanced the LC3II/LC3I ratio in lung tissue. Therefore, SP may improve LPS-induced ARDS in rats by inhibiting the activation of the PI3K/AKT/mTOR signaling pathway, promoting autophagy, decreasing the production and release of inflammatory markers, and reducing alveolar epithelial damage.

The role of KLF5 in gut microbiota and lung adenocarcinoma: unveiling programmed cell death pathways and prognostic biomarkers

Lung adenocarcinoma (LUAD) is the most important subtype of lung cancer. It is well known that the gut microbiome plays an important role in the pathophysiology of various diseases, including cancer, but little research has been done on the intestinal microbiome associated with LUAD. Utilizing bioinformatics tools and data analysis, we identified novel potential prognostic biomarkers for LUAD. To integrate differentially expressed genes and clinical significance modules, we used a weighted correlation network analysis system. According to the Peryton database and the gutMGene database, the composition and structure of gut microbiota in LUAD patients differed from those in healthy individuals. LUAD was associated with 150 gut microbiota and 767 gut microbiota targets, with Krüppel-like factor 5 (KLF5) being the most closely related. KLF5 was associated with immune status and correlated well with the prognosis of LUAD patients. The identification of KLF5 as a potential prognostic biomarker suggests its utility in improving risk stratification and guiding personalized treatment strategies for LUAD patients. Altogether, KLF5 could be a potential prognostic biomarker in LUAD.

Exploring immune-related pathogenesis in lung injury: Providing new insights Into ALI/ARDS

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) represent a significant global burden of morbidity and mortality, with lung injury being the primary cause of death in affected patients. The pathogenesis of lung injury, however, remains a complex issue. In recent years, the role of the immune system in lung injury has attracted extensive attention worldwide. Despite advancements in our understanding of various lung injury subtypes, significant limitations persist in both prevention and treatment. This review investigates the immunopathogenesis of ALI/ARDS, aiming to elucidate the pathological processes of lung injury mediated by dendritic cells (DCs), natural killer (NK) cells, phagocytes, and neutrophils. Furthermore, the article expounds on the critical contributions of gut microbiota, inflammatory pathways, and cytokine storms in the development of ALI/ARDS.

The role of gut-lung axis in COPD: Pathogenesis, immune response, and prospective treatment

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and healthcare burden worldwide. The progression of COPD is a combination of genetic predisposition and environmental factors, primarily cigarette smoking, and the underlying mechanisms are still unknown. Intestinal microecology impacts host immunity, metabolism, and resistance to pathogenic infections, which may be involved in pulmonary disease. Moreover, substantial interaction occurs between the intestinal and respiratory immune niches. After reviewing nearly 500 articles, we found the gut-lung axis plays an important role in the development of COPD. COPD patients often have dysbiosis of the intestinal microenvironment, which can affect host immunity through a series of mechanisms, exacerbating or protecting against COPD progression. This paper summarizes how the gut-lung axis influences COPD, including the alterations of intestinal microecology, the pathological mechanisms, and the involved immune responses. Finally, we summarize the latest research advances in COPD treatment from the perspective of regulating the gut-lung axis and intestinal immunity and evaluate the potential value of the gut-lung axis in improving COPD prognosis.

Xiaoqinglong decoction mitigates nasal inflammation and modulates gut microbiota in allergic rhinitis mice

Introduction

Allergic rhinitis (AR) is a respiratory immune system disorder characterized by dysregulation of immune responses. Within the context of AR, gut microbiota and its metabolites have been identified as contributors to immune modulation. These microorganisms intricately connect the respiratory and gut immune systems, forming what is commonly referred to as the gut-lung axis. Xiaoqinglong Decoction (XQLD), a traditional Chinese herbal remedy, is widely utilized in traditional Chinese medicine for the clinical treatment of AR. In this study, it is hypothesized that the restoration of symbiotic microbiota balance within the gut-lung axis plays a pivotal role in supporting the superior long-term efficacy of XQLD in AR therapy. Therefore, the primary objective of this research is to investigate the impact of XQLD on the composition and functionality of the gut microbiota in a murine model of AR.

Methods

An ovalbumin-sensitized mouse model to simulate AR was utilized, the improvement of AR symptoms after medication was investigated, and high-throughput sequencing was employed to analyze the gut microbiota composition.

Results

XQLD exhibited substantial therapeutic effects in AR mice, notably characterized by a significant reduction in allergic inflammatory responses, considerable alleviation of nasal symptoms, and the restoration of normal nasal function. Additionally, following XQLD treatment, the disrupted gut microbiota in AR mice displayed a tendency toward restoration, showing significant differences compared to the Western medicine (loratadine) group.

Discussion

This results revealed that XQLD may enhance AR allergic inflammatory responses through the regulation of intestinal microbiota dysbiosis in mice, thus influencing the dynamics of the gut-lung axis. The proposal of this mechanism provides a foundation for future research in this area.

Exploring the immune-inflammatory mechanism of Maxing Shigan Decoction in treating influenza virus A-induced pneumonia based on an integrated strategy of single-cell transcriptomics and systems biology

BACKGROUND

Influenza is an acute respiratory infection caused by influenza virus. Maxing Shigan Decoction (MXSGD) is a commonly used traditional Chinese medicine prescription for the prevention and treatment of influenza. However, its mechanism remains unclear.

METHOD

The mice model of influenza A virus pneumonia was established by nasal inoculation. After 3 days of intervention, the lung index was calculated, and the pathological changes of lung tissue were detected by HE staining. Firstly, transcriptomics technology was used to analyze the differential genes and important pathways in mouse lung tissue regulated by MXSGD. Then, real-time fluorescent quantitative PCR (RT-PCR) was used to verify the changes in mRNA expression in lung tissues. Finally, intestinal microbiome and intestinal metabolomics were performed to explore the effect of MXSGD on gut microbiota.

RESULTS

The lung inflammatory cell infiltration in the MXSGD group was significantly reduced (p < 0.05). The results of bioinformatics analysis for transcriptomics results show that these genes are mainly involved in inflammatory factors and inflammation-related signal pathways mediated inflammation biological modules, etc. Intestinal microbiome showed that the intestinal flora Actinobacteriota level and Desulfobacterota level increased in MXSGD group, while Planctomycetota in MXSGD group decreased. Metabolites were mainly involved in primary bile acid biosynthesis, thiamine metabolism, etc. This suggests that MXSGD has a microbial-gut-lung axis regulation effect on mice with influenza A virus pneumonia.

CONCLUSION

MXSGD may play an anti-inflammatory and immunoregulatory role by regulating intestinal microbiome and intestinal metabolic small molecules, and ultimately play a role in the treatment of influenza A virus pneumonia.

Microbiota and Immunity during Respiratory Infections: Lung and Gut Affair

Bacterial and viral respiratory tract infections are the most common infectious diseases, leading to worldwide morbidity and mortality. In the past 10 years, the importance of lung microbiota emerged in the context of pulmonary diseases, although the mechanisms by which it impacts the intestinal environment have not yet been fully identified. On the contrary, gut microbial dysbiosis is associated with disease etiology or/and development in the lung. In this review, we present an overview of the lung microbiome modifications occurring during respiratory infections, namely, reduced community diversity and increased microbial burden, and of the downstream consequences on host-pathogen interaction, inflammatory signals, and cytokines production, in turn affecting the disease progression and outcome. Particularly, we focus on the role of the gut-lung bidirectional communication in shaping inflammation and immunity in this context, resuming both animal and human studies. Moreover, we discuss the challenges and possibilities related to novel microbial-based (probiotics and dietary supplementation) and microbial-targeted therapies (antibacterial monoclonal antibodies and bacteriophages), aimed to remodel the composition of resident microbial communities and restore health. Finally, we propose an outlook of some relevant questions in the field to be answered with future research, which may have translational relevance for the prevention and control of respiratory infections.

People are an organic unity: Gut-lung axis and pneumonia

People are an organic unity. Every organ of our body doesn't exist alone. They are a part of our body and have important connections with other tissues or organs. The gut-lung axis is a typical example. Here, we reviewed the current research progress of the gut-lung axis. The main cross-talk between the intestine and lungs was sorted out, i.e. the specific interaction content contained in the gut-lung axis. We determine a relatively clear concept for the gut-lung axis, that is, the gut-lung axis is a cross-talk that the gut and lungs interact with each other through microorganisms and the immune system to achieve bidirectional regulation. The gut and lungs communicate with each other mainly through the immune system and symbiotic microbes, and these two pathways influence each other. The portal vein system and mesenteric lymphatics are the primary communication channels between the intestine and lungs. We also summarized the effects of pneumonia, including Coronavirus disease 2019 (COVID-19) and Community-Acquired Pneumonia (CAP), on intestinal microbes and immune function through the gut-lung axis, and discussed the mechanism of this effect. Finally, we explored the value of intestinal microbes and the gut-lung axis in the treatment of pneumonia through the effect of intestinal microbes on pneumonia.

Bibliometric analysis of intestinal microbiota and lung diseases

Background

Increasing evidence suggests a close association between the intestinal microbiome and the respiratory system, drawing attention to studying the gut-lung axis. This research employs bibliometric methods to conduct a visual analysis of literature in the field of intestinal microbiota and lung diseases over the past two decades. It offers scientific foundations for research directions and critical issues in this field.

Methods

We retrieved all articles on intestinal microbiota and lung diseases from the SCI-Expanded of WoSCC on October 25, 2023. The analysis included original articles and reviews published in English from 2011 to 2023. We utilized Python, VOSviewer, and CiteSpace to analyze the retrieved data visually.

Results

A total of 794 publications were analyzed. China ranked first in the number of publications, while the United States had the highest citations and H-index. Jian Wang was the most prolific author. Zhejiang University was the institution with the highest number of publications. Frontiers in Microbiology was the journal with the most publications. Author keywords appearing more than 100 times included "intestinal microbiota/microbiome", "microbiota/microbiome", and "gut-lung axis".

Conclusion

The correlation and underlying mechanisms between intestinal microbiota and lung diseases, including asthma, COPD, lung cancer, and respiratory infections, remain hot topics in research. However, understanding the mechanisms involving the gut-lung axis is still in its infancy and requires further elucidation.

Sodium butyrate ameliorates sepsis-associated lung injury by enhancing gut and lung barrier function in combination with modulation of CD4+Foxp3+ regulatory T cells

Sepsis-associated lung injury often coexists with intestinal dysfunction. Butyrate, an essential gut microbiota metabolite, participates in gut-lung crosstalk and has immunoregulatory effects. This study aims to investigate the effect and mechanism of sodium butyrate (NaB) on lung injury. Sepsis-associated lung injury was established in mice by cecal ligation and puncture (CLP). Mice in treatment groups received NaB gavage after surgery. The survival rate, the oxygenation index and the lung wet-to-dry weight (W/D) ratio were calculated respectively. Pulmonary and intestinal histologic changes were observed. The total protein concentration in bronchoalveolar lavage fluid (BALF) was measured, and inflammatory factors in serum and BALF were examined. Diamine oxidase (DAO), lipopolysaccharide (LPS), and surfactant-associated protein D (SP-D) levels in serum and amphiregulin in lung tissue were assessed. Intercellular junction protein expression in the lung and intestinal tissues were examined. Changes in immune cells were analyzed. NaB treatment improved the survival rate, the oxygenation index and the histologic changes. NaB decreased the W/D ratio, total protein concentration, and the levels of proinflammatory cytokines, as well as SP-D, DAO and LPS, while increased the levels of anti-inflammatory cytokines and amphiregulin. The intercellular junction protein expression were improved by NaB. Furthermore, the CD4+/CD8+ T-cell ratio and the proportion of CD4+Foxp3+ regulatory T cells (Tregs) were increased by NaB. Our data suggested that NaB gavage effectively improved the survival rate and mitigated lung injury in CLP mice. The possible mechanism was that NaB augmented CD4+Foxp3+ Tregs and enhanced the barrier function of the gut and the lung.

Role of gut microbes in acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI) is an acute, diffuse inflammatory lung condition triggered by factors of severe infections, trauma, shock, burns, ischemia-reperfusion, and mechanical ventilation. It is primarily characterized by refractory hypoxemia and respiratory distress. The more severe form, acute respiratory distress syndrome (ARDS), can progress to multi-organ failure and has a high mortality rate. Despite extensive research, the exact pathogenesis of ALI and ARDS remains complex and not fully understood. Recent advancements in studying the gut microecology of patients have revealed the critical role that gut microbes play in ALI/ARDS onset and progression. While the exact mechanisms are still under investigation, evidence increasingly points to the influence of gut microbes and their metabolites on ALI/ARDS. This review aims to summarize the role of gut microbes and their metabolites in ALI/ARDS caused by various triggers. Moreover, it explores potential mechanisms and discusses how gut microbe-targeting interventions might offer new clinical strategies for the treatment of ALI/ARDS.

QingXiaoWuWei decoction alleviates methicillin-resistant Staphylococcus aureus-induced pneumonia in mice by regulating metabolic remodeling and macrophage gene expression network via the microbiota-short-chain fatty acids axis

IMPORTANCE

Methicillin-resistant Staphylococcus aureus (MRSA) colonizes the upper respiratory airways and is resistant to antibiotics. MRSA is a frequently acquired infection in hospital and community settings, including cases of MRSA-induced pneumonia. Multidrug-resistant Staphylococcus aureus and the limited efficacy of antibiotics necessitate alternative strategies for preventing or treating the infection. QingXiaoWuWei decoction (QXWWD) protects against both gut microbiota dysbiosis and MRSA-induced pneumonia. Furthermore, the QXWWD-regulated metabolic remodeling and macrophage gene expression network contribute to its protective effects through the microbiota-short-chain fatty acid axis. The results of this study suggest that QXWWD and its pharmacodynamic compounds might have the potential to prevent and treat pulmonary infections, especially those caused by multidrug-resistant organisms. Our study provides a theoretical basis for the future treatment of pulmonary infectious diseases by manipulating gut microbiota and their metabolites via traditional Chinese medicine.

Microbial influence on triggering and treatment of host cancer: An intestinal barrier perspective

Inflammatory bowel disease (IBD) is associated with complex complications that may lead to tumors. However, research on the mechanisms underlying susceptibility to chronic immune diseases and cancer pathogenesis triggered by the inflammatory environment remains limited. An imbalance in the host gut microbiota often accompanies intestinal inflammation. The delayed recovery of the dysregulated intestinal microbiota may exacerbate systemic inflammatory responses, multiorgan pathology, and metabolic disorders. This delay may also facilitate bacterial translocation. This review examined the relationship between gut barrier disruption and unbalanced microbial translocation and their impact on the brain, liver, and lungs. We also explored their potential roles in tumor initiation. Notably, the role of the intestinal microbiota in the development of inflammation is linked to the immune surveillance function of the small intestine and the repair status of the intestinal barrier. Moreover, adherence to a partially anti-inflammatory diet can aid in preventing the malignant transformation of inflammation by repairing the intestinal barrier and significantly reducing inflammation. In conclusion, enhancing intestinal barrier function may be a novel strategy for preventing and treating chronic malignancies in the intestine and other body areas.

Does postoperative pulmonary infection correlate with intestinal flora following gastric cancer surgery? - a nested case-control study

Introduction

The primary objective of this study was to investigate the potential correlation between gut microbes and postoperative pulmonary infection in gastric cancer patients. Additionally, we aimed to deduce the mechanism of differential functional genes in disease progression to gain a better understanding of the underlying pathophysiology.

Methods

A nested case-control study design was utilized to enroll patients with gastric cancer scheduled for surgery at West China Hospital of Sichuan University. Patients were categorized into two groups, namely, the pulmonary infection group and the control group, based on the development of postoperative pulmonary infection. Both groups were subjected to identical perioperative management protocols. Fecal samples were collected 24 h postoperatively and upon pulmonary infection diagnosis, along with matched controls. The collected samples were subjected to 16S rDNA and metagenomic analyses, and clinical data and blood samples were obtained for further analysis.

Results

A total of 180 fecal specimens were collected from 30 patients in both the pulmonary infection and control groups for 16S rDNA analysis, and 3 fecal samples from each group were selected for metagenomic analysis. The study revealed significant alterations in the functional genes of the intestinal microbiome in patients with postoperative pulmonary infection in gastric cancer, primarily involving Klebsiella, Enterobacter, Ruminococcus, and Collinsella. During postoperative pulmonary infection, gut flora and inflammatory factors were found to be associated with the lipopolysaccharide synthesis pathway and short-chain fatty acid (SCFA) synthesis pathway.

Discussion

The study identified enriched populations of Klebsiella, Escherella, and intestinal bacteria during pulmonary infection following gastric cancer surgery. These bacteria were found to regulate the lipopolysaccharide synthesis pathway, contributing to the initiation and progression of pulmonary infections. Inflammation modulation in patients with postoperative pulmonary infection may be mediated by short-chain fatty acids. The study also revealed that SCFA synthesis pathways were disrupted, affecting inflammation-related immunosuppression pathways. By controlling and maintaining intestinal barrier function, SCFAs may potentially reduce the occurrence of pulmonary infections after gastric cancer surgery. These findings suggest that targeting the gut microbiome and SCFA synthesis pathways may be a promising approach for preventing postoperative pulmonary infections in gastric cancer patients.

Cryptotanshinone alleviates radiation-induced lung fibrosis via modulation of gut microbiota and bile acid metabolism

Cryptotanshinone (CPT), a major biological active ingredient extracted from root of Salvia miltiorrhiza (Danshen), has shown several pharmacological activities. However, the effect of CPT on radiation-induced lung fibrosis (RILF) is unknown. In this study, we explored the protective effects of CPT on RILF from gut-lung axis angle, specifically focusing on the bile acid (BA)-gut microbiota axis. We found that CPT could inhibit the process of epithelial mesenchymal transformation (EMT) and suppress inflammation to reduce the deposition of extracellular matrix in lung fibrosis in mice induced by radiation. In addition, 16S rDNA gene sequencing and BAs-targeted metabolomics analysis demonstrated that CPT could improve the dysbiosis of gut microbiota and BA metabolites in RILF mice. CPT significantly enriched the proportion of the beneficial genera Enterorhabdus and Akkermansia, and depleted that of Erysipelatoclostridium, which were correlated with increased intestinal levels of several farnesoid X receptor (FXR) natural agonists, such as deoxycholic acid and lithocholic acid, activating the FXR pathway. Taken together, these results suggested that CPT can regulate radiation-induced disruption of gut microbiota and BAs metabolism of mice, and reduce the radiation-induced lung inflammation and fibrosis. Thus, CPT may be a promising drug candidate for treating RILF.

The lung-gut crosstalk in respiratory and inflammatory bowel disease

Both lung and gut belong to the common mucosal immune system (CMIS), with huge surface areas exposed to the external environment. They are the main defense organs against the invasion of pathogens and play a key role in innate and adaptive immunity. Recently, more and more evidence showed that stimulation of one organ can affect the other, as exemplified by intestinal complications during respiratory disease and vice versa, which is called lung-gut crosstalk. Intestinal microbiota plays an important role in respiratory and intestinal diseases. It is known that intestinal microbial imbalance is related to inflammatory bowel disease (IBD), this imbalance could impact the integrity of the intestinal epithelial barrier and leads to the persistence of inflammation, however, gut microbial disturbances have also been observed in respiratory diseases such as asthma, allergy, chronic obstructive pulmonary disease (COPD), and respiratory infection. It is not fully clarified how these disorders happened. In this review, we summarized the latest examples and possible mechanisms of lung-gut crosstalk in respiratory disease and IBD and discussed the strategy of shaping intestinal flora to treat respiratory diseases.

YuPingFengSan ameliorates LPS-induced acute lung injury and gut barrier dysfunction in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yupingfengsan (YPFS) is a traditional Chinese medicine decoction. YPFS comprises Astragalus mongholicus Bunge (Huangqi), Atractylodes rubra Dekker (Baizhu), and Saposhnikovia divaricata (Turcz.ex Ledeb.) Schischk (Fangfeng). YPFS is commonly used to treat chronic obstructive pulmonary disease, asthma, respiratory infections, and pneumonia, but the mechanism of action remains unclear.

AIM OF THE STUDY

Acute lung injury (ALI) and its severe form of acute respiratory distress syndrome (ARDS) cause morbidity and mortality in critical patients. YPFS is a commonly used herbal soup to treat respiratory and immune system diseases. Nevertheless, the effect of YPFS on ALI remains unclear. This study aimed to investigate the effect of YPFS on lipopolysaccharide (LPS)-induced ALI in mice and elucidate its potential molecular mechanisms.

MATERIALS AND METHODS

The major components of YPFS were detected by High-performance liquid chromatography (HPLC). C57BL/6J mice were given YPFS for seven days and then treated with LPS. IL-1β, IL-6, TNF-α, IL-8, iNOS, NLRP3, PPARγ, HO-1, ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, EnaCγ mRNA in lung and ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ mRNA in colon tissues were measured by Real-Time Quantitative PCR (RT-qPCR). The expressions of TLR4, MyD88, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), ASC, MAPK signaling pathway, Nrf2, and HO-1 in the lung were detected by Western blot. Plasma inflammatory factors Interleukin (IL)-1β, IL-6, and Tumor Necrosis Factor-α (TNF-α) were determined by Enzyme-linked Immunosorbent Assay (ELISA). Lung tissues were processed for H & E staining, and colon tissues for HE, WGA-FITC, and Alcian Blue staining.

RESULTS

The results showed that YPFS administration alleviated lung injury and suppressed the production of inflammatory factors, including IL-1β, IL-6, and TNF-α. Additionally, YPFS reduced pulmonary edema by promoting the expressions of aquaporin and sodium channel-related genes (AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ). Further, YPFS intervention exhibited a therapeutic effect on ALI by inhibiting the activation of the NLRP3 inflammasome and MAPK signaling pathways. Finally, YPFS improved gut barrier integrity and suppressed intestinal inflammation in LPS-challenged mice.

CONCLUSIONS

YPFS protected mice against LPS-induced ALI by attenuating lung and intestinal tissue damage. This study sheds light on the potential application of YPFS to treat ALI/ARDS.

Global Research Trends on the Link Between the Microbiome and COPD: A Bibliometric Analysis

Background

The pathogenesis of chronic obstructive pulmonary disease (COPD) has been studied in relation to the microbiome, providing space for more targeted interventions and new treatments. Numerous papers on the COPD microbiome have been reported in the last 10 years, yet few publications have used bibliometric methods to evaluate this area.

Methods

We searched the Web of Science Core Collection for all original research articles in the field of COPD microbiome from January 2011 to August 2022 and used CiteSpace for visual analysis.

Results

A total of 505 relevant publications were obtained, and the number of global publications in this field is steadily increasing every year, with China and the USA occupying the first two spots in international publications. Imperial College London and the University of Leicester produced the most publications. Brightling C from the UK was the most prolific writer, while Huang Y and Sze M from the USA were first and second among the authors cited. The American Journal of Respiratory and Critical Care Medicine had the highest frequency of citations. The top 10 institutions, cited authors and journals are mostly from the UK and the US. In the ranking of citations, the first article was a paper published by Sze M on changes in the lung tissue's microbiota in COPD patients. The keywords "exacerbation", "gut microbiota", "lung microbiome", "airway microbiome", "bacterial colonization", and "inflammation" were identified as cutting-edge research projects for 2011-2022.

Conclusion

Based on the visualization results, in the future, we can use the gut-lung axis as the starting point to explore the immunoinflammatory mechanism of COPD, and study how to predict the effects of different treatments of COPD by identifying the microbiota, and how to achieve the optimal enrichment of beneficial bacteria and the optimal consumption of harmful bacteria to improve COPD.

Ameliorating role of Tetrastigma hemsleyanum polysaccharides in antibiotic-induced intestinal mucosal barrier dysfunction in mice based on microbiome and metabolome analyses

The intestinal mucosal barrier is one of the important barriers to prevent harmful substances and pathogens from entering the body environment and to maintain intestinal homeostasis. This study investigated the reparative effect and possible mechanism of Tetrastigma hemsleyanum polysaccharides (THP) on ceftriaxone-induced intestinal mucosal damage. Our results suggested that THP repaired the mechanical barrier damage of intestinal mucosa by enhancing the expression of intestinal tight junction proteins, reducing intestinal mucosal permeability and improving the pathological state of intestinal epithelial cells. Intestinal immune and chemical barrier was further restored by THP via the increment of the body's cytokine levels, intestinal SIgA levels, intestinal goblet cell number, intestinal mucin-2 levels, and short-chain fatty acid levels. In addition, THP increased the abundance of probiotic bacteria (such as Lactobacillus), reduced the abundance of harmful bacteria (such as Enterococcus) to repair the intestinal biological barrier, restored intestinal mucosal barrier function, and maintains intestinal homeostasis. The possible mechanisms were related to sphingolipid metabolism, linoleic acid metabolism, and d-glutamine and D-glutamate metabolism. Our results demonstrated the potential therapeutic effect of THP against intestinal flora disorders and intestinal barrier function impairment caused by antibiotics.

Probiotic-based nanoparticles for targeted microbiota modulation and immune restoration in bacterial pneumonia

While conventional bacterial pneumonia mainly centralizes avoidance of bacterial colonization, it remains unclear how to restore the host immunity for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia. Here, probiotic-based nanoparticles of OASCLR were formed by coating chitosan, hyaluronic acid and ononin on living Lactobacillus rhamnosus. OASCLR nanoparticles could effectively kill various clinic common pathogens and antibacterial efficiency was >99.97%. Importantly, OASCLR could modulate lung microbiota, increasing the overall richness and diversity of microbiota by decreasing pathogens and increasing probiotic and commensal bacteria. Additionally, OASCLR could target inflammatory macrophages by the interaction of OASCLR with the macrophage binding site of CD44 and alleviate overactive immune responses for hyperactive immunocompetent pneumonia. Surprisingly, OASCLR could break the state of the macrophage's poor phagocytic ability by upregulating the expression of the extracellular matrix assembly, immune activation and fibroblast activation in immunocompromised pneumonia. The macrophage's phagocytic ability was increased from 2.61% to 12.3%. Our work provides a potential strategy for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia.

A Comprehensive Analysis of Microflora and Metabolites in the Development of Ulcerative Colitis into Colorectal Cancer Based on the Lung–Gut Correlation Theory

The lungs and large intestine can co-regulate inflammation and immunity through the lung–gut axis, in which the transportation of the gut microbiota and metabolites is the most important communication channel. In our previous study, not only did the composition of the gut microbiota and metabolites related to inflammation change significantly during the transition from ulcerative colitis (UC) to colorectal cancer (CRC), but the lung tissues also showed corresponding inflammatory changes, which indicated that gastrointestinal diseases can lead to pulmonary diseases. In order to elucidate the mechanisms of this lung–gut axis, metabolites in bronchoalveolar lavage fluid (BALF) and lung tissues were detected using UHPLC–Q-TOF-MS/MS technology, while microbiome characterization was performed in BALF using 16S rDNA sequencing. The levels of pulmonary metabolites changed greatly during the development of UC to CRC. Among these changes, the concentrations of linoleic acid and 7-hydroxy-3-oxocholic acid gradually increased during the development of UC to CRC. In addition, the composition of the pulmonary microbiota also changed significantly, with an increase in the Proteobacteria and an obvious decrease in the Firmicutes. These changes were consistent with our previous studies of the gut. Collectively, the microbiota and metabolites identified above might be the key markers related to lung and gut diseases, which can be used as an indication of the transition of diseases from the gut to the lung and provide a scientific basis for clinical treatment.

Herbal medicine in the treatment of COVID-19 based on the gut-lung axis

Respiratory symptoms are most commonly experienced by patients in the early stages of novel coronavirus disease 2019 (COVID-19). However, with a better understanding of COVID-19, gastrointestinal symptoms such as diarrhea, nausea, and vomiting have attracted increasing attention. The gastrointestinal tract may be a target organ of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The intestinal microecological balance is a crucial factor for homeostasis, including immunity and inflammation, which are closely related to COVID-19. Herbal medicine can restore intestinal function and regulate the gut flora structure. Herbal medicine has a long history of treating lung diseases from the perspective of the intestine, which is called the gut-lung axis. The physiological activities of guts and lungs influence each other through intestinal flora, microflora metabolites, and mucosal immunity. Microecological modulators are included in the diagnosis and treatment protocols for COVID-19. In this review, we demonstrate the relationship between COVID-19 and the gut, gut-lung axis, and the role of herbal medicine in treating respiratory diseases originating from the intestinal tract. It is expected that the significance of herbal medicine in treating respiratory diseases from the perspective of the intestinal tract could lead to new ideas and methods for treatment.

Graphical abstract

http://links.lww.com/AHM/A33.

The effect of Lactobacillus rhamnosus B10 on alcoholic liver injury and intestinal microbiota in alcohol-induced mice model

Lactobacillus rhamnosus B10 (L. rhamnosus B10) isolated from the baby feces was given to an alcohol mice model, aiming to investigate the effects of L. rhamnosus B10 on alcoholic liver injury by regulating intestinal microbiota. C57BL/6N mice were fed with liquid diet Lieber-DeCarli with or without 5% (v/v) ethanol for 8 weeks, and treated with L. rhamnosus B10 at the last 2 weeks. The results showed that L. rhamnosus B10 decreased the serum total cholesterol (1.48 mmol/L), triglycerides (0.97 mmol/L), alanine aminotransferase (26.4 U/L), aspartate aminotransferase (14.2 U/L), lipopolysaccharide (0.23 EU/mL), and tumor necrosis factor-α (138 pg/mL). In addition, L. rhamnosus B10 also reduced the liver triglycerides (1.02 mmol/g prot), alanine aminotransferase (17.8 mmol/g prot) and aspartate aminotransferase (12.5 mmol/g prot) in alcohol mice, thereby ameliorating alcohol-induced liver injury. The changes of intestinal microbiota composition on class, family and genus level in cecum were analyzed. The intestinal symbiotic abundance of Firmicutes was elevated while gram-negative bacteria Proteobacteria and Deferribacteres was decreased in alcohol mice treated with L. rhamnosus B10 for 2 weeks. In summary, this study provided evidence for the therapeutic effects of probiotics on alcoholic liver injury by regulating intestinal flora.

Developing sensor materials for screening intestinal diseases

Intestinal diseases that have high mortality and morbidity rates and bring huge encumbrance to the public medical system and economy worldwide, have always been the focus of clinicians and scientific researchers. Early diagnosis and intervention are valuable in the progression of many intestinal diseases. Fortunately, the emergence of sensor materials can effectively assist clinical early diagnosis and health monitoring. By accurately locating the lesion and sensitively analyzing the level of disease markers, these sensor materials can help to precisely diagnose the stage and state of lesions, thereby avoiding delayed treatment. In this review, we provide comprehensive and in-depth knowledge of diagnosing and monitoring intestinal diseases with the assistance of sensor materials, particularly emphasizing their design and application in bioimaging and biodetection. This review is dedicated to conveying practical applications of sensor materials in the intestine, critical analysis of their mechanisms and applications and discussion of their future roles in medicine. We believe that this review will promote multidisciplinary communication between material science, medicine and relevant engineering fields, thus improving the clinical translation of sensor materials.

Targeting the Pulmonary Microbiota to Fight against Respiratory Diseases

The mucosal immune system of the respiratory tract possesses an effective “defense barrier” against the invading pathogenic microorganisms; therefore, the lungs of healthy organisms are considered to be sterile for a long time according to the strong pathogens-eliminating ability. The emergence of next-generation sequencing technology has accelerated the studies about the microbial communities and immune regulating functions of lung microbiota during the past two decades. The acquisition and maturation of respiratory microbiota during childhood are mainly determined by the birth mode, diet structure, environmental exposure and antibiotic usage. However, the formation and development of lung microbiota in early life might affect the occurrence of respiratory diseases throughout the whole life cycle. The interplay and crosstalk between the gut and lung can be realized by the direct exchange of microbial species through the lymph circulation, moreover, the bioactive metabolites produced by the gut microbiota and lung microbiota can be changed via blood circulation. Complicated interactions among the lung microbiota, the respiratory viruses, and the host immune system can regulate the immune homeostasis and affect the inflammatory response in the lung. Probiotics, prebiotics, functional foods and fecal microbiota transplantation can all be used to maintain the microbial homeostasis of intestinal microbiota and lung microbiota. Therefore, various kinds of interventions on manipulating the symbiotic microbiota might be explored as novel effective strategies to prevent and control respiratory diseases.

A Natural Plant Source-Tea Polyphenols, a Potential Drug for Improving Immunity and Combating Virus

The coronavirus disease 2019 (COVID-19) is still in a global epidemic, which has profoundly affected people’s lives. Tea polyphenols (TP) has been reported to enhance the immunity of the body to COVID-19 and other viral infectious diseases. The inhibitory effect of TP on COVID-19 may be achieved through a series of mechanisms, including the inhibition of multiple viral targets, the blocking of cellular receptors, and the activation of transcription factors. Emerging evidence shows gastrointestinal tract is closely related to respiratory tract, therefore, the relationship between the state of the gut–lung axis microflora and immune homeostasis of the host needs further research. This article summarized that TP can improve the disorder of flora, reduce the occurrence of cytokine storm, improve immunity, and prevent COVID-19 infection. TP may be regarded as a potential and valuable source for the design of new antiviral drugs with high efficiency and low toxicity.

Gut Microbiota and SCFAs Play Key Roles in QingFei Yin Recipe Anti-Streptococcal Pneumonia Effects

Emerging evidence has revealed the presence in animals of a bidirectional regulatory “lung-gut axis” that provides resistance to respiratory infections. Clues to the existence of this system stem from observations that respiratory infections are often accompanied by gastrointestinal symptoms, whereby intestinal microbiota appear to play pivotal roles in combating pathogenic infections. Importantly, short-chain fatty acids (SCFAs) produced by the gut microbiota appear to serve as the biological link between host immune defenses and gut flora. Streptococcus pneumoniae (S.pn), the main cause of lower respiratory tract infections, is involved in more than 1.189 million deaths per year. QingFei Yin (QFY) is known for its excellent therapeutic efficacy in combating bacterial lung infections. In this study, effects of S.pn infection on gut homeostasis were assessed using 16S RNA-based microbiota community profiling analysis. In addition, potential mechanisms underlying QFY recipe beneficial therapeutic effects against bacterial pneumonia were explored using S.pn-infected gut microbiota-depleted mice. Results of data analysis indicated that QFY treatment alleviated lung infection-associated pathogenic processes, while also promoting repair of disordered gut flora and counteracting S.pn infection-associated decreases in levels of SCFAs, particularly of acetate and butyrate. Mechanistically, QFY treatment suppressed inflammatory lung injury through inhibition of the host NF-κB-NLRP3 pathway. These results inspired us to identify precise QFY targets and mechanisms underlying QFY anti-inflammatory effects. In addition, we conducted an in-depth evaluation of QFY as a potential treatment for bacterial pneumonia.

Gut microbiota dysbiosis contributes to the development of chronic obstructive pulmonary disease

BACKGROUND

Dysbiosis of the gut microbiome is involved in the pathogenesis of various diseases, but the contribution of gut microbes to the progression of chronic obstructive pulmonary disease (COPD) is still poorly understood.

METHODS

We carried out 16S rRNA gene sequencing and short-chain fatty acid analyses in stool samples from a cohort of 73 healthy controls, 67 patients with COPD of GOLD stages I and II severity, and 32 patients with COPD of GOLD stages III and IV severity. Fecal microbiota from the three groups were then inoculated into recipient mice for a total of 14 times in 28 days to induce pulmonary changes. Furthermore, fecal microbiota from the three groups were inoculated into mice exposed to smoke from biomass fuel to induce COPD-like changes.

RESULTS

We observed that the gut microbiome of COPD patients varied from that of healthy controls and was characterized by a distinct overall microbial diversity and composition, a Prevotella-dominated gut enterotype and lower levels of short-chain fatty acids. After 28 days of fecal transplantation from COPD patients, recipient mice exhibited elevated lung inflammation. Moreover, when mice were under both fecal transplantation and biomass fuel smoke exposure for a total of 20 weeks, accelerated declines in lung function, severe emphysematous changes, airway remodeling and mucus hypersecretion were observed.

CONCLUSION

These data demonstrate that altered gut microbiota in COPD patients is associated with disease progression in mice model.

Gastrointestinal Bleeding, but Not Other Gastrointestinal Symptoms, Is Associated With Worse Outcomes in COVID-19 Patients

Background: Patients with coronavirus disease 2019 (COVID-19) can present with gastrointestinal (GI) symptoms. However, the prevalence of GI symptoms and their association with outcomes remain controversial in COVID-19 patients. Methods: All COVID-19 patients consecutively admitted to the Wuhan Huoshenshan hospital from February 2020 to April 2020 were collected. Disease severity and outcomes were compared between COVID-19 patients with and without GI symptoms. Logistic regression analyses were performed to evaluate the association of GI symptoms with the composite endpoint and death in COVID-19 patients. A composite endpoint was defined as transfer to intensive care unit, requirement of mechanical ventilation, and death. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Results: Overall, 2,552 COVID-19 patients were included. The prevalence of GI symptoms was 21.0% (537/2,552). Diarrhea (8.9%, 226/2,552) was the most common GI symptom. Patients with GI symptoms had significantly higher proportions of severe COVID-19 and worse outcomes than those without. Univariate logistic regression analyses demonstrated that GI symptoms were significantly associated with the composite endpoint (OR = 2.426, 95% CI = 1.608-3.661; P < 0.001) and death (OR = 2.137, 95% CI = 1.209-3.778; P = 0.009). After adjusting for age, sex, and severe/critical COVID-19, GI symptoms were still independently associated with the composite endpoint (OR = 2.029, 95% CI = 1.294-3.182; P = 0.002), but not death (OR = 1.726, 95% CI = 0.946-3.150; P = 0.075). According to the type of GI symptoms, GI bleeding was an independent predictor of the composite endpoint (OR = 8.416, 95% CI = 3.465-20.438, P < 0.001) and death (OR = 6.640, 95% CI = 2.567-17.179, P < 0.001), but not other GI symptoms (i.e., diarrhea, abdominal discomfort, nausea and/or vomiting, constipation, acid reflux and/or heartburn, or abdominal pain). Conclusion: GI symptoms are common in COVID-19 patients and may be associated with their worse outcomes. Notably, such a negative impact of GI symptoms on the outcomes should be attributed to GI bleeding.

Investigating efficacy of "microbiota modulation of the gut-lung Axis" combined with chemotherapy in patients with advanced NSCLC: study protocol for a multicenter, prospective, double blind, placebo controlled, randomized trial

Background

Most NSCLCs metastasised out of the lungs at the time of diagnosis and cannot be surgically removed . Cytotoxic chemotherapy drugs have become the main treatment in recent decades, especially in patients with NSCLC without EGFR, ALK, and ROS gene mutations. The prognosis of lung cancer is poor, and the overall 5-year survival rate is only 9–13%. Therefore the treatment of advanced NSCLC remains a significant medical need. Recent studies have shown a significant relationship between the gut-lung axis microecology and malignant tumors. Intestinal probiotics are likely to play a role in inhibiting tumorigenesis through “intestinal-pulmonary axis microecological regulation”. This study will seek to investigate the efficacy of “Microbiota modulation of the Gut-Lung Axis” combined with chemotherapy in patients with advanced NSCLC.

Methods

The research is a multicenter, prospective, double blind, placebo controlled, randomized trial. Based on the theoretical basis of “intestinal and lung axis microecological adjustment”, combined with traditional platinum-containing two-drug chemotherapy, the efficacy of the new therapy on patients with advanced NSCLC was observed. Collect the basic information of the patient, and study the effect of platinum-based combined chemotherapy on the diversity of intestinal flora in patients with lung cancer after receiving chemotherapy treatment, feces before and after chemotherapy, and the status and extent of adverse reactions during chemotherapy . A total of 180 subjects were included, divided into a control group (platinum-containing dual-drug chemotherapy) and an intervention group (platinum-containing dual-drug chemotherapy combined with Bifico), and were randomly assigned to the group 1:1.

Discussion

As a result, intestinal-pulmonary microecological balance could become a new target for the treatment of lung cancer. This study explores the combination of intestinal microecological regulation and chemotherapy to provide new treatment strategies and basis for lung cancer patients. It can help prolong the survival time of lung cancer patients and improve the quality of life, thereby generating huge economic and social benefits. The results can be promoted and applied to units engaged in the treatment of lung cancer.

Trial registration number

NCT03642548, date: August 22, 2018, the first version protocol. The URL of trial registry record: https://clinicaltrials.gov/ct2/show/NCT03642548?term=NCT03642548&draw=2&rank=1.

Immunosuppressive effect of mesenchymal stem cells on lung and gut CD8+ T cells in lipopolysaccharide-induced acute lung injury in mice

OBJECTIVES

Acute lung injury (ALI) not only affects pulmonary function but also leads to intestinal dysfunction, which in turn contributes to ALI. Mesenchymal stem cell (MSC) transplantation can be a potential strategy in the treatment of ALI. However, the mechanisms of synergistic regulatory effects by MSCs on the lung and intestine in ALI need more in-depth study.

MATERIALS AND METHODS

We evaluated the therapeutic effects of MSCs on the murine model of lipopolysaccharide (LPS)-induced ALI through survival rate, histopathology and bronchoalveolar lavage fluid. Metagenomic sequencing was performed to assess the gut microbiota. The levels of pulmonary and intestinal inflammation and immune response were assessed by analysing cytokine expression and flow cytometry.

RESULTS

Mesenchymal stem cells significantly improved the survival rate of mice with ALI, alleviated histopathological lung damage, improved intestinal barrier integrity, and reduced the levels of inflammatory cytokines in the lung and gut. Furthermore, MSCs inhibited the inflammatory response by decreasing the infiltration of CD8+ T cells in both small-intestinal lymphocytes and Peyer's patches. The gut bacterial community diversity was significantly altered by MSC transplantation. Furthermore, depletion of intestinal bacterial communities with antibiotics resulted in more severe lung and gut damages and mortality, while MSCs significantly alleviated lung injury due to their immunosuppressive effect.

CONCLUSIONS

The present research indicates that MSCs attenuate lung and gut injury partly via regulation of the immune response in the lungs and intestines and gut microbiota, providing new insights into the mechanisms underlying the therapeutic effects of MSC treatment for LPS-induced ALI.

Gut-Lung Dysbiosis Accompanied by Diabetes Mellitus Leads to Pulmonary Fibrotic Change through the NF-κB Signaling Pathway

Growing evidence shows that the lungs are an unavoidable target organ of diabetic complications. However, the pathologic mechanisms of diabetic lung injury are still controversial. This study demonstrated the dysbiosis of the gut and lung microbiome, pulmonary alveolar wall thickening, and fibrotic change in streptozotocin-induced diabetic mice and antibiotic-induced gut dysbiosis mice compared with controls. In both animal models, the NF-κB signaling pathway was activated in the lungs. Enhanced pulmonary alveolar well thickening and fibrotic change appeared in the lungs of transgenic mice expressing a constitutively active NF-κB mutant compared with wild type. When lincomycin hydrochloride-induced gut dysbiosis was ameliorated by fecal microbiota transplant, enhanced inflammatory response in the intestine and pulmonary fibrotic change in the lungs were significantly decreased compared with lincomycin hydrochloride-treated mice. Furthermore, the application of fecal microbiota transplant and baicalin could also redress the microbial dysbiosis of the gut and lungs in streptozotocin-induced diabetic mice. Taken together, these data suggest that multiple as yet undefined factors related to microbial dysbiosis of gut and lungs cause pulmonary fibrogenesis associated with diabetes mellitus through an NF-κB signaling pathway.

Effect of gut microbiota on LPS-induced acute lung injury by regulating the TLR4/NF-kB signaling pathway

Acute lung injury (ALI) is a common acute respiratory disease treated in the clinic. Intestinal microflora disorder affect lung diseases through the gut-lung axis. In this study, we explored the regulatory mechanism of the gut flora in the host defense against lipopolysaccharide (LPS)-induced ALI through the TLR4/NF-kB pathway by constructing a gut microflora dysbiosis-model with antibiotic administration and reconstruction of the intestinal microecology. Then, high-throughput sequencing was performed, and the levels of secreted IgA (sIgA), β-defensins, and Muc2 were measured to assess the gut flora and mucosal barrier. The expression of TLR4, NF-kB, TNF-α, IL-1β, oxidative stress and the lung wet/dry (W/D) ratio were evaluated to assess lung damage. Hematoxylin and eosin (HE) staining was performed to evaluate the damage to the gut and lung tissues. Accordingly, gut microbiota imbalance may regulate the TLR4/NF-kB signaling pathway in the lung immune system, activating oxidative stress in the lung and mediating lung injury through the regulation of the gut barrier. However, fecal microbiota transplantation (FMT) impairs the activity of the TLR4/NF-kB signaling pathway in the lung and decreases oxidative stress in animals with ALI by restoring the gut microecology. CONCLUSIONS: Our results indicated the protective effect of gut flora in regulating immunity of LPS-induced ALI by modulating the TLR4/NF-kB signaling pathway which may induce inflammation and oxidative stress.

Gut microbiota influence tumor development and Alter interactions with the human immune system

Recent scientific advances have greatly enhanced our understanding of the complex link between the gut microbiome and cancer. Gut dysbiosis is an imbalance between commensal and pathogenic bacteria and the production of microbial antigens and metabolites. The immune system and the gut microbiome interact to maintain homeostasis of the gut, and alterations in the microbiome composition lead to immune dysregulation, promoting chronic inflammation and development of tumors. Gut microorganisms and their toxic metabolites may migrate to other parts of the body via the circulatory system, causing an imbalance in the physiological status of the host and secretion of various neuroactive molecules through the gut-brain axis, gut-hepatic axis, and gut-lung axis to affect inflammation and tumorigenesis in specific organs. Thus, gut microbiota can be used as a tumor marker and may provide new insights into the pathogenesis of malignant tumors.

Clinical Study of Correlation for the Intestinal and Pharyngeal Microbiota in the Premature Neonates

Objective: There are mutual influences between intestine and lung, that propose a concept of the gut-lung axis, but the mechanism is still unclear. Microbial colonization in early life plays an important role in regulating intestinal and lung function. In order to explore the characteristics of early microbiota on the gut-lung axis, we studied the correlation between intestinal and pharyngeal microbiota on day 1 and day 28 after birth in premature neonates. Methods: Thirteen neonates born at 26-32 weeks gestational age (GA) hospitalized at the neonatal intensive care unit (NICU) of the West China Second Hospital of Sichuan University were enrolled in this study. Stool samples and pharyngeal swabs samples were collected from each neonate on the first day (T1) and the 28th day (T28) after birth. Total bacterial DNA was extracted and sequenced using the Illumina MiSeq Sequencing System based on the V3-V4 hyper-variable regions of the 16S rRNA gene. Based on the sequencing results, the composition of the intestinal and pharyngeal microbiota was compared and analyzed. Results: At T1, the difference in microbial composition between intestine and pharynx was not statistically significant. The intestinal microbiota was mainly composed of Unidentified Enterobacteriaceae, Ralstonia, Streptococcus, Fusobacterium, Ureaplasma, etc. The pharyngeal microbiota was mainly composed of Ureaplasma, Bacteroides, Fusobacterium, etc. Ureaplasma and Fusobacterium were detected in both intestine and pharynx. At T28, there was a significant difference in microbial composition between intestine and pharynx (p < 0.001). The intestinal microbiota was mainly composed of Unidentified Clostridiales, Klebsiella, Unidentified Enterobacteriaceae, Enterobacter, Streptococcus, etc. Pharyngeal microbiota was mainly composed of Streptococcus, Rothia, etc. Streptococcus was detected in both intestine and pharynx. Conclusions: The intestine and pharynx of premature neonates have a unique microbial composition, and share some common microbiota. Whether these microbiotas play a role in the mechanism of gut-lung crosstalk needs further study.

Bacterial association and comparison between lung and intestine in rats

The association between lung and intestine has already been reported, but the differences in community structures or functions between lung and intestine bacteria yet need to explore. To explore the differences in community structures or functions, the lung tissues and fecal contents in rats were collected and analyzed through 16S rRNA sequencing. It was found that intestine bacteria was more abundant and diverse than lung bacteria. In intestine bacteria, Firmicutes and Bacteroides were identified as major phyla while Lactobacillus was among the most abundant genus. However, in lung the major identified phylum was Proteobacteria and genus Pseudomonas was most prominent genus. On the other hand, in contrast the lung bacteria was more concentrated in cytoskeleton and function in energy production and conversion. While, intestine bacteria were enriched in RNA processing, modification chromatin structure, dynamics and amino acid metabolism. The study provides the basis for understanding the relationships between lung and intestine bacteria.

Systems pharmacology reveals the mechanism of activity of Ge-Gen-Qin-Lian decoction against LPS-induced acute lung injury: A novel strategy for exploring active components and effective mechanism of TCM formulae

Acute lung injury (ALI), a severe and life-threatening inflammation of the lung, with high morbidity and mortality, underscoring the urgent need for novel treatments. Ge-Gen-Qin-Lian decoction (GQD), a classic Chinese herbal formula, has been widely used to treat intestine-related diseases in the clinic for centuries. In recent years, a growing number of studies have found that GQD has a favorable anti-inflammatory effect. With the further study on the viscera microbiota, the link between the lungs and the gut-the gut-lung axis has been established. Based on the theory of the gut-lung axis, we used systems pharmacology to explore the effects and mechanisms of GQD treatment in ALI. Hypothesizing that GQD inhibits ALI progression, we used the experimental model of lipopolysaccharide (LPS)-induced ALI in Balb/c mice to evaluate the therapeutic potential of GQD. Our results showed that GQD exerted protective effects against LPS-induced ALI by reducing pulmonary edema and microvascular permeability. Meanwhile, GQD can downregulate the expression of LPS-induced TNF-α, IL-1β, and IL-6 in lung tissue, bronchoalveolar lavage fluid (BLAF), and serum. To further understand the molecular mechanism of GQD in the treatment of ALI, we used the network pharmacology to predict the disease targets of the active components of GQD. Lung tissue and serum samples of the mice were separately analyzed by transcriptomics and metabolomics. KEGG pathway analysis of network pharmacology and transcriptomics indicated that PI3K/Akt signaling pathway was significantly enriched, suggesting that it may be the main regulatory pathway for GQD treatment of ALI. By immunohistochemical analysis and apoptosis detection, it was verified that GQD can inhibit ALI apoptosis through PI3K/Akt signaling pathway. Then, we used the PI3K inhibitor LY294002 to block the PI3K/Akt signaling pathway, and reversely verified that the PI3K/Akt signaling pathway is the main pathway of GQD anti-ALI. In addition, differential metabolites in mice serum samples indicate that GQD can inhibit the inflammatory process of ALI by reversing the imbalance of energy metabolism. Our study showed that, GQD did have a better therapeutic effect on ALI, and initially elucidated its molecular mechanism. Thus, GQD could be exploited to develop novel therapeutics for ALI. Moreover, our study also provides a novel strategy to explore active components and effective mechanism of TCM formula combined with TCM theory to treat ALI.