Gut Microbiota Protected Against pseudomonas aeruginosa Pneumonia via Restoring Treg/Th17 Balance and Metabolism

Targeting gut-immune-heart modulate cardiac remodeling after acute myocardial infarction

The gut microbiota interacts with the host to regulate disease and health status. An increasing number of studies have recognized the bidirectional regulation between gut microbiota and immune cells, which plays a significant role in the etiology and prognosis of diseases. Gut microbiota is also a crucial regulatory factor in cardiovascular diseases. After acute myocardial infarction, myocardial and endothelial damage rapidly triggers an inflammatory response, activating the immune system and disrupting the gut microbiota ecology, thereby affecting cardiac remodeling after acute myocardial infarction and potentially leading to heart failure. We have elucidated the regulatory mechanisms of complex intercellular networks in the immune system during cardiac remodeling after acute myocardial infarction. Furthermore, this research examines the roles and mechanisms of gut microbiota, immune cells, and gut metabolites in relation to cardiac remodeling and heart failure after myocardial infarction. Finally, we discuss the potential of targeting gut immune cells as an effective approach to prevent and treat heart failure after acute myocardial infarction in the future, through methods such as dietary regulation, probiotic supplementation, and microbiota transplantation.

Advances in gut-lung axis research: clinical perspectives on pneumonia prevention and treatment

In recent years, the study of the interaction between gut microbiota and distant organs such as the heart, lungs, brain, and liver has become a hot topic in the field of gut microbiology. With a deeper understanding of its immune regulation and mechanisms of action, these findings have increasingly highlighted their guiding value in clinical practice. The gut is not only the largest digestive organ in the human body but also the habitat for most microorganisms. Imbalances in gut microbial communities have been associated with various lung diseases, such as allergic asthma and cystic fibrosis. Furthermore, gut microbial communities have significant impacts on metabolic function and immune responses. Their metabolites not only regulate gastrointestinal immune systems but may also affect distant organs such as the lungs and brain. As one of the most common types of respiratory system diseases worldwide, pulmonary infections have high morbidity and mortality rates. Pulmonary infections caused by immune dysfunction can lead to gastrointestinal problems like diarrhea, further resulting in imbalances within complex interactions that are associated with abnormal manifestations under disequilibrium conditions. Meanwhile, clinical interventions can significantly modulate the composition of gut microbiota, and alteration in gut microbiota may subsequently indicate susceptibility to pulmonary infections and even contribute to the prevention or regulation of their progression. This review delves into the interaction between gut microbiota and pulmonary infections, elucidating the latest advancements in gut-lung axis research and providing a fresh perspective for the treatment and prevention of pneumonia.

Harnessing the human gut microbiota: an emerging frontier in combatting multidrug-resistant bacteria

Antimicrobial resistance (AMR) has become a major and escalating global health threat, undermining the effectiveness of current antibiotic and antimicrobial therapies. The rise of multidrug-resistant bacteria has led to increasingly difficult-to-treat infections, resulting in higher morbidity, mortality, and healthcare costs. Tackling this crisis requires the development of novel antimicrobial agents, optimization of current therapeutic strategies, and global initiatives in infection surveillance and control. Recent studies highlight the crucial role of the human gut microbiota in defending against AMR pathogens. A balanced microbiota protects the body through mechanisms such as colonization resistance, positioning it as a key ally in the fight against AMR. In contrast, gut dysbiosis disrupts this defense, thereby facilitating the persistence, colonization, and dissemination of resistant pathogens. This review will explore how gut microbiota influence drug-resistant bacterial infections, its involvement in various types of AMR-related infections, and the potential for novel microbiota-targeted therapies, such as fecal microbiota transplantation, prebiotics, probiotics, phage therapy. Elucidating the interactions between gut microbiota and AMR pathogens will provide critical insights for developing novel therapeutic strategies to prevent and treat AMR infections. While previous reviews have focused on the general impact of the microbiota on human health, this review will specifically look at the latest research on the interactions between the gut microbiota and the evolution and spread of AMR, highlighting potential therapeutic strategies.

A gut Eggerthella lenta-derived metabolite impairs neutrophil function to aggravate bacterial lung infection

The composition of the gut microbiota in patients with bronchiectasis has been proven to be distinct from that of healthy individuals, and this disrupted gut microbiota can exacerbate lung infections. However, the responsible microbes and mechanisms in the "gut-lung" axis in bronchiectasis remain unknown. Here, we report that Eggerthella lenta was enriched in the gut, and taurine ursodeoxycholic acid (TUDCA) was enriched in both the guts and sera of patients with bronchiectasis, with both being associated with disease severity. Fecal microbiota transfer from patients with bronchiectasis as well as administration of E. lenta independently exacerbated pulmonary Pseudomonas aeruginosa infections in murine models. E. lenta-associated TUDCA bound adenosine monophosphate-activated protein kinase (AMPK) within neutrophils and interfered with the interaction between liver kinase B1 and AMPK, with a consequential decrease in AMPK phosphorylation. This ultimately reduced ATP production in neutrophils, inhibited their function, and compromised P. aeruginosa elimination from the lung, aggravating tissue injury. Metformin treatment improved disease severity and outcome in the mouse models. In sum, the gut bacterium E. lenta raises the stakes of bacterial lung infection because it causes dysfunction of neutrophils circulated from serum to lung via the metabolite TUDCA. Interventions targeting E. lenta or AMPK phosphorylation may serve as adjunctive strategies to complement existing approaches for managing chronic pulmonary infection in bronchiectasis and other chronic respiratory disease states.

Beyond the Hayflick limit: How microbes influence cellular aging

Cellular senescence, a complex biological process resulting in permanent cell-cycle arrest, is central to aging and age-related diseases. A key concept in understanding cellular senescence is the Hayflick Limit, which refers to the limited capacity of normal human cells to divide, after which they become senescent. Senescent cells (SC) accumulate with age, releasing pro-inflammatory and tissue-remodeling factors collectively known as the senescence-associated secretory phenotype (SASP). The causes of senescence are multifaceted, including telomere attrition, oxidative stress, and genotoxic damage, and they extend to influences from microbial sources. Research increasingly emphasizes the role of the microbiome, especially gut microbiota (GM), in modulating host senescence processes. Beneficial microbial metabolites, such as short-chain fatty acids (SCFAs), support host health by maintaining antioxidant defenses and reducing inflammation, potentially mitigating senescence onset. Conversely, pathogenic bacteria like Pseudomonas aeruginosa and Helicobacter pylori introduce factors that damage host DNA or increase ROS, accelerating senescence via pathways such as NF-κB and p53-p21. This review explores the impact of bacterial factors on cellular senescence, highlighting the role of specific bacterial toxins in promoting senescence. Additionally, it discusses how dysbiosis and the loss of beneficial microbial species further contribute to age-related cellular deterioration. Modulating the gut microbiome to delay cellular senescence opens a path toward targeted anti-aging strategies. This work underscores the need for deeper investigation into microbial influence on aging, supporting innovative interventions to manage and potentially reverse cellular senescence.

Gut microbiota contributes to the intestinal and extraintestinal immune homeostasis by balancing Th17/Treg cells

Gut microbiota is generally considered to play an important role in host health due to its extensive immunomodulatory activities. Th17 and Treg cells are two important CD4+ T cell subsets involved in immune regulation, and their imbalance is closely tied to many immune diseases. Recently, abundant researches have highlighted the importance of gut microbiota in supporting intestinal and extraintestinal immunity through the balance of Th17 and Treg cells. Here, we presented a comprehensive review of these findings. This review first provided an overview of gut microbiota, along with Th17/Treg cell differentiation and cytokine production. Subsequently, the review summarized the regulatory effects of gut microbiota (in terms of species, components, and metabolites) on the Th17/Treg cell balance in the local intestines and extraintestinal organs, such as lung, liver, brain, kidney, and bone. Specifically, the Th17 and Treg cells that can be modulated by gut microbiota originate not only from the gut and extraintestinal organs, but also from peripheral blood and spleen. Then, the microbial therapeutics, including probiotics, prebiotics, postbiotics, and fecal microbiota transplantation (FMT), were also reviewed because of their therapeutic potentials in addressing intestinal and extraintestinal diseases via the Th17/Treg axis. Finally, the review discussed the clinical applications and future study prospects of microbial therapeutics by targeting the Th17/Treg cell balance. In conclusion, this review focused on elucidating the regulatory effects of gut microbiota in balancing Th17/Treg cells to maintain intestinal and extraintestinal immune homeostasis, contributing to the further development and promotion of microbial therapeutics.

Integration of microbiomics, metabolomics, and transcriptomics reveals the therapeutic mechanism underlying Fuzheng-Qushi decoction for the treatment of lipopolysaccharide-induced lung injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzheng-Qushi decoction (FZQS) is a practical Chinese herbal formula for relieving cough and fever. Therefore, the action and specific molecular mechanism of FZQS in the treatment of lung injury with cough and fever as the main symptoms need to be further investigated.

AIMS OF THE STUDY

To elucidate the protective effects of FZQS against lung injury in mice and reveal its potential targets and key biological pathways for the treatment of lung injury based on transcriptomics, microbiomics, and untargeted metabolomics analyses.

MATERIALS AND METHODS

Lipopolysaccharide (LPS) was used to induce a mouse model of lung injury, followed by the administration of FZQS. ELISA was used to detect IL-1β, IL-6, IL-17A, IL-4, IL-10, and TNF-α, in mouse lung tissues. Macrophage polarization and neutrophil activation were measured by flow cytometry. RNA sequencing (RNA-seq) was applied to screen for differentially expressed genes (DEGs) in lung tissues. RT-qPCR and Western blot assays were utilized to validate key DEGs and target proteins in lung tissues. 16S rRNA sequencing was employed to characterize the gut microbiota of mice. Metabolites in the gut were analyzed using untargeted metabolomics.

RESULTS

FZQS treatment significantly ameliorated lung histopathological damage, decreased pro-inflammatory cytokine levels, and increased anti-inflammatory cytokine levels. M1 macrophage levels in the peripheral blood decreased, M2 macrophage levels increased, and activated neutrophils were inhibited in mice with LPS-induced lung injury. Importantly, transcriptomic analysis showed that FZQS downregulated macrophage and neutrophil activation and migration and adhesion pathways by reversing 51 DEGs, which was further confirmed by RT-qPCR and Western blot analysis. In addition, FZQS modulated the dysbiosis of the gut microbiota by reversing the abundance of Corynebacterium, Facklamia, Staphylococcus, Paenalcaligenes, Lachnoclostridium, norank_f_Muribaculaceae, and unclassified_f_Lachnospiraceae. Meanwhile, metabolomics analysis revealed that FZQS significantly regulated tryptophan metabolism by reducing the levels of 3-Indoleacetonitrile and 5-Hydroxykynurenine.

CONCLUSION

FZQS effectively ameliorated LPS-induced lung injury by inhibiting the activation, migration, and adhesion of macrophages and neutrophils and modulating gut microbiota and its metabolites.

Novel Therapeutic Target for ALI/ARDS: Forkhead Box Transcription Factors

ALI/ARDS can be a pulmonary manifestation of a systemic inflammatory response or a result of overexpression of the body's normal inflammatory response involving various effector cells, cytokines, and inflammatory mediators, which regulate the body's immune response through different signalling pathways. Forkhead box transcription factors are evolutionarily conserved transcription factors that play a crucial role in various cellular processes, such as cell cycle progression, proliferation, differentiation, migration, metabolism, and DNA damage response. Transcription factors control protein synthesis by regulating gene transcription levels, resulting in diverse biological outcomes. The Fox family plays a role in activating or inhibiting the expression of various molecules related to ALI/ARDS through phosphorylation, acetylation/deacetylation, and control of multiple signalling pathways. An in-depth analysis of the integrated Fox family's role in ALI/ARDS can aid in the development of potential diagnostic and therapeutic targets for the condition.

Chinese traditional medicine DZGP beneficially affects gut microbiome, serum metabolites and recovery from rheumatoid arthritis through mediating NF-κB signaling pathway

Rheumatoid arthritis (RA) is globally treated with several commercially available anti-inflammatory and analgesic drugs, which pose adverse side effects in many cases. Due to increasing population affected by autoimmune disorder of joints inflammation, it is crucial to use natural therapies, which are less toxic at metabolic level and promote gut health. In this study, we investigated the potential role of a locally developed traditional Chinese medicine (TCM), namely Duzheng tablet (DZGP) in controlling the RA. For this purpose, we introduced RA in male mice and divided them into 5 different groups. High throughput transcriptome analysis of synovial cells after DZGP treatment in arthritic mice revealed a significant alteration of gene expression. The correlation analysis of transcriptome with metabolites revealed that DZGP specifically targeted the B cells mediated immunity pathways. Treatment with DZGP inhibited the cytokines production, while reducing the production of inflammatory TNF-α, which led to the alleviation of inflammatory response in arthritic mice. Additionally, we applied integrated approach using 16S rDNA sequencing to understand the microbial population in relation to metabolites accumulation. The results showed that DZGP promoted the healthy gut microbiota by maintaining the ratio of Firmicutes and Bacteroidota and introduction of two additional phyla namely, Verrucomicrobiota and Cyanobacteria. Therefore, it is concluded that DZGP offers an advantage over commercial drug by changing the metabolic profile, gut microbiota while exhibiting lower cellular toxicity.

The Hydroxypyridinone Iron Chelator DIBI Reduces Bacterial Load and Inflammation in Experimental Lung Infection

Iron plays a critical role in lung infections due to its function in the inflammatory immune response but also as an important factor for bacterial growth. Iron chelation represents a potential therapeutic approach to inhibit bacterial growth and pathologically increased pro-inflammatory mediator production. The present study was designed to investigate the impact of the iron chelator DIBI in murine lung infection induced by intratracheal Pseudomonas aeruginosa (strain PA14) administration. DIBI is a polymer with a polyvinylpyrrolidone backbone containing nine 3-hydroxy-1-(methacrylamidoethyl)-2-methyl-4(1H) pyridinone (MAHMP) residues per molecule and was given by intraperitoneal injection either as a single dose (80 mg/kg) immediately after PA14 administration or a double dose (second dose 4 h after PA14 administration). The results showed that lung NF-κBp65 levels, as well as levels of various inflammatory cytokines (TNFα, IL-1β, IL-6) both in lung tissue and bronchoalveolar lavage fluid (BALF), were significantly increased 24 h after PA14 administration. Single-dose DIBI did not affect the bacterial load or inflammatory response in the lungs or BALF. However, two doses of DIBI significantly decreased bacterial load, attenuated NF-κBp65 upregulation, reduced inflammatory cytokines production, and relieved lung tissue damage. Our findings support the conclusion that the iron chelator, DIBI, can reduce lung injury induced by P. aeruginosa, via its anti-bacterial and anti-inflammatory effects.

ZEB2 alleviates Hirschsprung's-associated enterocolitis by promoting the proliferation and differentiation of enteric neural precursor cells via the Notch-1/Jagged-2 pathway

BACKGROUND

Hirschsprung's-associated enterocolitis (HAEC) is a prevalent complication of Hirschsprung's disease (HSCR). Zinc finger E-box binding homeobox 2 (ZEB2) and Notch-1/Jagged-2 are dysregulated in HSCR, but their role in HAEC progression remains poorly understood. We aimed to explore the role and underlying mechanism of enteric neural precursor cells (ENPCs) and the ZEB2/Notch-1/Jagged-2 pathway in HAEC development.

METHODS

Colon tissues were collected from HSCR and HAEC patients. ENPCs were isolated from the HAEC group and stimulated by lipopolysaccharide (LPS). The expressions of ZEB2/Notch-1/Jagged-2 were measured using RT-qPCR and Western blot. Immunofluorescence and cell counting kit-8 assays were performed to assess the differentiation and proliferation of ENPCs. Inflammatory factors were measured by ELISA kits. Co-immunoprecipitation and bioinformatic analysis were used to explore the interaction between ZEB2 and Notch-1. Small interfering RNA and overexpression vectors were used to investigate the role and mechanism of ZEB2 and Notch-1 in regulating ENPCs' proliferation and differentiation during HAEC progression.

RESULTS

We observed increased LPS in the colon tissues of HAEC, with downregulated ZEB2 expression and upregulated Notch-1/Jagged-2 expression. ZEB2 interacts with Notch-1. LPS treatment downregulated ZEB2 expression, upregulated Notch-1/Jagged-2 expression, and induced proliferation and differentiation disorders in ENPCs, which were reversed by the knockdown of Notch-1. Furthermore, overexpression of ZEB2 inhibited Notch-1/Jagged-2 signaling and ameliorated inflammation and dysfunction in LPS-induced ENPCs. Notch-1 overexpression enhanced LPS-induced dysfunction, but this effect was antagonized by the overexpression of ZEB2.

CONCLUSION

Overexpression of ZEB2 ameliorates LPS-induced ENPCs' dysfunction via the Notch-1/Jagged-2 pathway, thus playing a role in HAEC.

Gut microbes improve prognosis of Klebsiella pneumoniae pulmonary infection through the lung-gut axis

Background

The gut microbiota plays a vital role in the development of sepsis and in protecting against pneumonia. Previous studies have demonstrated the existence of the gut-lung axis and the interaction between the gut and the lung, which is related to the prognosis of critically ill patients; however, most of these studies focused on chronic lung diseases and influenza virus infections. The purpose of this study was to investigate the effect of faecal microbiota transplantation (FMT) on Klebsiella pneumoniae-related pulmonary infection via the gut-lung axis and to compare the effects of FMT with those of traditional antibiotics to identify new therapeutic strategies.

Methods

We divided the mice into six groups: the blank control (PBS), pneumonia-derived sepsis (KP), pneumonia-derived sepsis + antibiotic (KP + PIP), pneumonia-derived sepsis + faecal microbiota transplantation(KP + FMT), antibiotic treatment control (KP+PIP+PBS), and pneumonia-derived sepsis+ antibiotic + faecal microbiota transplantation (KP + PIP + FMT) groups to compare the survival of mice, lung injury, inflammation response, airway barrier function and the intestinal flora, metabolites and drug resistance genes in each group.

Results

Alterations in specific intestinal flora can occur in the gut of patients with pneumonia-derived sepsis caused by Klebsiella pneumoniae. Compared with those in the faecal microbiota transplantation group, the antibiotic treatment group had lower levels of proinflammatory factors and higher levels of anti-inflammatory factors but less amelioration of lung pathology and improvement of airway epithelial barrier function. Additionally, the increase in opportunistic pathogens and drug resistance-related genes in the gut of mice was accompanied by decreased production of favourable fatty acids such as acetic acid, propionic acid, butyric acid, decanoic acid, and secondary bile acids such as chenodeoxycholic acid 3-sulfate, isodeoxycholic acid, taurodeoxycholic acid, and 3-dehydrocholic acid; the levels of these metabolites were restored by faecal microbiota transplantation. Faecal microbiota transplantation after antibiotic treatment can gradually ameliorate gut microbiota disorder caused by antibiotic treatment and reduce the number of drug resistance genes induced by antibiotics.

Conclusion

In contrast to direct antibiotic treatment, faecal microbiota transplantation improves the prognosis of mice with pneumonia-derived sepsis caused by Klebsiella pneumoniae by improving the structure of the intestinal flora and increasing the level of beneficial metabolites, fatty acids and secondary bile acids, thereby reducing systemic inflammation, repairing the barrier function of alveolar epithelial cells, and alleviating pathological damage to the lungs. The combination of antibiotics with faecal microbiota transplantation significantly alleviates intestinal microbiota disorder, reduces the selection for drug resistance genes caused by antibiotics, and mitigates lung lesions; these effects are superior to those following antibiotic monotherapy.

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.

A new perspective on gut-lung axis affected through resident microbiome and their implications on immune response in respiratory diseases

The highly diverse microbial ecosystem of the human body colonizes the gastrointestinal tract has a profound impact on the host's immune, metabolic, endocrine, and other physiological processes, which are all interconnected. Specifically, gut microbiota has been found to play a crucial role in facilitating the adaptation and initiation of immune regulatory response through the gastrointestinal tract affecting the other distal mucosal sites such as lungs. A tightly regulated lung-gut axis during respiratory ailments may influence the various molecular patterns that instructs priming the disease severity to dysregulate the normal function. This review provides a comprehensive summary of current research on gut microbiota dysbiosis in respiratory diseases including asthma, pneumonia, bronchopneumonia, COPD during infections and cancer. A complex-interaction among gut microbiome, associated metabolites, cytokines, and chemokines regulates the protective immune response activating the mucosal humoral and cellular response. This potential mechanism bridges the regulation patterns through the gut-lung axis. This paper aims to advance the understanding of the crosstalk of gut-lung microbiome during infection, could lead to strategize to modulate the gut microbiome as a treatment plan to improve bad prognosis in various respiratory diseases.

[Analysis of gut target microbiota and species difference in patients with obstructive sleep apnea based on 16S rRNA sequencing]

OBJECTIVE

To explore the difference in gut microbiota composition between patients with obstructive sleep apnea (OSA) and healthy individuals and the role of gut microbiota in the pathogenesis of OSA.

METHODS

Thirty-nine patients with OSA admitted to our hospital between May and December, 2022 and 20 healthy individuals were enrolled in this study. Stool samples were collected from all the participants for analysis of microbiome composition using 16S rRNA high- throughput sequencing analysis. The alpha diversity, beta diversity, and species difference were determined between the two groups and marker species analysis and metabolic pathway function prediction analysis were performed.

RESULTS

The species diversity (Shannon and Simpson) indexes, richness (observed species) and evenness (Pielou) of gut microbiota were significantly lower in OSA patients than in the healthy individuals (P < 0.05). The OSA patients had also a significantly lowered community diversity (P < 0.05) with different gut microbial communities from those of the healthy individuals shown by increased relative abundance of potentially pathogenic bacteria such as Pseudomonas and Monocytogenes (P < 0.05). LEfSe analysis showed that the abundance of 23 species of gut microbiota differed significantly between the two groups and the OSA patients had significant increases in the abundance of Pseudomonas, Meganomonas, and Fusobacterium (P < 0.05). The differential marker flora affected host homeostasis. Random Forest and ROC curve analyses confirmed that Pseudomonas could be used as important biomarkers for a differential diagnosis. Metabolic pathway function prediction analysis showed that biosynthesis function had the greatest contribution to maintaining gut microbiota homeostasis, and Pseudomonas affected the occurrence and progression of OSA by participating in aromatic bioamine degradation and ketogluconic acid metabolic pathway.

CONCLUSION

OSA patients have obvious gut microbiota disturbances, and Pseudomonas may affect the development of OSA by participating in substance metabolism to serve as the potential target gut bacteria for OSA treatment.

Restoring the epigenetic landscape of lung microbiome: potential therapeutic approach for chronic respiratory diseases

BACKGROUND

Chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and bronchiectasis, present significant threats to global health. Recent studies have revealed the crucial role of the lung microbiome in the development of these diseases. Pathogens have evolved complex strategies to evade the immune response, with the manipulation of host cellular epigenetic mechanisms playing a pivotal role. There is existing evidence regarding the effects of Pseudomonas on epigenetic modifications and their association with pulmonary diseases. Therefore, this study aims to directly assess the connection between Pseudomonas abundance and chronic respiratory diseases. We hope that our findings will shed light on the molecular mechanisms behind lung pathogen infections.

METHODS

We analyzed data from 366 participants, including individuals with COPD, acute exacerbations of COPD (AECOPD), bronchiectasis, and healthy individuals. Previous studies have given limited attention to the impact of Pseudomonas on these groups and their comparison with healthy individuals. Two independent datasets from different ethnic backgrounds were used for external validation. Each dataset separately analyzed bacteria at the genus level.

RESULTS

The study reveals that Pseudomonas, a bacterium, was consistently found in high concentrations in all chronic lung disease datasets but it was present in very low abundance in the healthy datasets. This suggests that Pseudomonas may influence cellular mechanisms through epigenetics, contributing to the development and progression of chronic respiratory diseases.

CONCLUSIONS

This study emphasizes the importance of understanding the relationship between the lung microbiome, epigenetics, and the onset of chronic pulmonary disease. Enhanced recognition of molecular mechanisms and the impact of the microbiome on cellular functions, along with a better understanding of these concepts, can lead to improved diagnosis and treatment.

Co-Housing and Fecal Microbiota Transplantation: Technical Support for TCM Herbal Treatment of Extra-Intestinal Diseases Based on Gut Microbial Ecosystem Remodeling

Dysregulation of the gut microbial ecosystem (GME) (eg, alterations in the gut microbiota, gut-derived metabolites, and gut barrier) may contribute to the onset and progression of extra-intestinal diseases. Previous studies have found that Traditional Chinese Medicine herbs (TCMs) play an important role in manipulating the GME, but a prominent obstacle in current TCM research is the causal relationship between GME and disease amelioration. Encouragingly, co-housing and fecal microbiota transplantation (FMT) provide evidence-based support for TCMs to treat extra-intestinal diseases by targeting GME. In this review, we documented the principles, operational procedures, applications and limitations of the key technologies (ie, co-housing and FMT); furthermore, we provided evidence that TCM works through the GME, especially the gut microbiota (eg, SCFA- and BSH-producing bacteria), the gut-derived metabolites (eg, IS, pCS, and SCFAs), and intestinal barrier to alleviate extra-intestinal diseases. This will be beneficial in constructing microecological pathways for TCM treatment of extra-intestinal diseases in the future.

The impact of aging-induced gut microbiome dysbiosis on dendritic cells and lung diseases

Aging is an inevitable natural process that impacts every individual, and understanding its effect on the gut microbiome and dendritic cell (DC) functionality in elderly subjects is crucial. DCs are vital antigen-presenting cells (APCs) that orchestrate the immune response, maintaining immune tolerance to self-antigens and bridging innate and adaptive immunity. With aging, there is a shift toward nonspecific innate immunity, resulting in a decline in adaptive immune responses. This alteration raises significant concerns about managing the health of an elderly population. However, the precise impact of aging and microbiome changes on DC function and their implications in lung-associated diseases remain relatively understudied. To illuminate this subject, we will discuss recent advancements in understanding the connections between aging, gut dysbiosis, DCs, and lung diseases. Emphasizing the key concepts linking age-related gut microbiome changes and DC functions, we will focus on their relevance to overall health and immune response in elderly individuals. This article aims to improve our understanding of the intricate relationship between aging, gut microbiome, and DCs, potentially benefiting the management of age-associated diseases and promoting healthy aging.

Gut Microbiome-Based Therapeutics in Critically Ill Adult Patients-A Narrative Review

The gut microbiota plays a crucial role in the human microenvironment. Dysbiosis of the gut microbiota is a common pathophysiological phenomenon in critically ill patients. Therefore, utilizing intestinal microbiota to prevent complications and improve the prognosis of critically ill patients is a possible therapeutic direction. The gut microbiome-based therapeutics approach focuses on improving intestinal microbiota homeostasis by modulating its diversity, or treating critical illness by altering the metabolites of intestinal microbiota. There is growing evidence that fecal microbiota transplantation (FMT), selective digestive decontamination (SDD), and microbiota-derived therapies are all effective treatments for critical illness. However, different treatments are appropriate for different conditions, and more evidence is needed to support the selection of optimal gut microbiota-related treatments for different diseases. This narrative review summarizes the curative effects and limitations of microbiome-based therapeutics in different critically ill adult patients, aiming to provide possible directions for gut microbiome-based therapeutics for critically ill patients such as ventilator-associated pneumonia, sepsis, acute respiratory distress syndrome, and COVID-19, etc.

Butyrate protects against MRSA pneumonia via regulating gut-lung microbiota and alveolar macrophage M2 polarization

IMPORTANCE

Pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) continues to carry a high burden in terms of mortality. With the roles of gut microbiota in mediating lung diseases being gradually uncovered, the details of the molecular mechanism of the "gut-lung axis" mediated by beneficial microorganisms and small-molecule metabolites have gradually attracted the attention of researchers. However, further studies are still necessary to determine the efficacy of microbial-based interventions. Our findings indicate that sodium butyrate (NaB) alleviates MRSA-induced pulmonary inflammation by improving gut-lung microbiota and promoting M2 polarization of alveolar macrophages. Therefore, the preventive administration of NaB might be explored as an effective strategy to control MRSA pneumonia.

Regulatory T cells in lung disease and transplantation

Pulmonary disease can refer to the disease of the lung itself or the pulmonary manifestations of systemic diseases, which are often connected to the malfunction of the immune system. Regulatory T (Treg) cells have been shown to be important in maintaining immune homeostasis and preventing inflammatory damage, including lung diseases. Given the increasing amount of evidence linking Treg cells to various pulmonary conditions, Treg cells might serve as a therapeutic strategy for the treatment of lung diseases and potentially promote lung transplant tolerance. The most potent and well-defined Treg cells are Foxp3-expressing CD4+ Treg cells, which contribute to the prevention of autoimmune lung diseases and the promotion of lung transplant rejection. The protective mechanisms of Treg cells in lung disease and transplantation involve multiple immune suppression mechanisms. This review summarizes the development, phenotype and function of CD4+Foxp3+ Treg cells. Then, we focus on the therapeutic potential of Treg cells in preventing lung disease and limiting lung transplant rejection. Furthermore, we discussed the possibility of Treg cell utilization in clinical applications. This will provide an overview of current research advances in Treg cells and their relevant application in clinics.

Prevention and treatment of rheumatoid arthritis through traditional Chinese medicine: role of the gut microbiota

Recently, despite the increasing availability of treatments for Rheumatoid arthritis (RA), the incidence of RA and associated disability-adjusted life years have been on the rise globally in the late decades. At present, accumulating evidence has been advanced that RA is related to the gut microbiota, therefore, the therapeutic approaches for RA by regulating the gut microbiota are anticipated to become a new means of treatment. Traditional Chinese medicine (TCM) can regulate immunity, reduce inflammation and improve quality of life in various ways. Moreover, it can treat diseases by affecting the gut microbiota, which is a good way to treat RA. In this review, we mainly explore the relationship between TCM and gut microbiota regarding the perspective of treating RA. Moreover, we comprehensively summarize the roles of gut microbiota in the onset, development, progression, and prognosis of RA. Additionally, we elucidate the mechanism of TCM prevention and treatment of RA by the role of microbiota. Finally, we provide an evidence-based rationale for further investigation of microbiota-targeted intervention by TCM.

Fecal microbiota transplantation inhibited neuroinflammation of traumatic brain injury in mice via regulating the gut-brain axis

Introduction

Recent studies have highlighted the vital role of gut microbiota in traumatic brain injury (TBI). Fecal microbiota transplantation (FMT) is an effective means of regulating the microbiota-gut-brain axis, while the beneficial effect and potential mechanisms of FMT against TBI remain unclear. Here, we elucidated the anti-neuroinflammatory effect and possible mechanism of FMT against TBI in mice via regulating the microbiota-gut-brain axis.

Methods

The TBI mouse model was established by heavy object falling impact and then treated with FMT. The neurological deficits, neuropathological change, synaptic damage, microglia activation, and neuroinflammatory cytokine production were assessed, and the intestinal pathological change and gut microbiota composition were also evaluated. Moreover, the population of Treg cells in the spleen was measured.

Results

Our results showed that FMT treatment significantly alleviated neurological deficits and neuropathological changes and improved synaptic damage by increasing the levels of the synaptic plasticity-related protein such as postsynaptic density protein 95 (PSD-95) and synapsin I in the TBI mice model. Moreover, FMT could inhibit the activation of microglia and reduce the production of the inflammatory cytokine TNF-α, alleviating the inflammatory response of TBI mice. Meanwhile, FMT treatment could attenuate intestinal histopathologic changes and gut microbiota dysbiosis and increase the Treg cell population in TBI mice.

Conclusion

These findings elucidated that FMT treatment effectively suppressed the TBI-induced neuroinflammation via regulating the gut microbiota-gut-brain axis, and its mechanism was involved in the regulation of peripheral immune cells, which implied a novel strategy against TBI.

Imbalance of gut microbiota is involved in the development of chronic obstructive pulmonary disease: A review

Chronic obstructive pulmonary disease (COPD) is a common chronic disease characterized by chronic airway inflammation and remodeling, which seriously endangers human health. Recent developments in genomics and metabolomics have revealed the roles of the gut microbiota and its metabolites in COPD. Dysbiosis of the gut microbiota directly increases gut permeability, thereby promoting the translocation of pathological bacteria. The gut microbiota and associated metabolites may influence the development and progression of COPD by modulating immunity and inflammation. Furthermore, the systemic hypoxia and oxidative stress that occur in COPD may also be involved in intestinal dysfunction. The cross-talk between the gut and lungs is known as the gut-lung axis; however, an overview of its mechanism is lacking. This review highlights the critical and complex interplay of gut microbiota and immune responses in the gut-lung axis, further explores possible links between the gut and lungs, and summarizes new interventions through diet, probiotics, vitamins, and fecal microbiota transplantation, which are critical to COPD.

Ficolin A knockout alleviates sepsis-induced severe lung injury in mice by restoring gut Akkermansia to inhibit S100A4/STAT3 pathway

Acute lung injury (ALI) is a life-threatening disease with high morbidity and mortality. Our previous results demonstrated that Ficolin A (FcnA) protected against lipopolysaccharide (LPS)-induced mild ALI via activating complement, however the mechanism of severe lung damage caused by sepsis remains unclear. This study aimed to investigate whether FcnA modulated gut microbiota to affect the progression of sepsis-induced severe ALI. Fcna^-/- and Fcnb^-/- C57BL/6 mice were applied to establish the ALI model by injection of LPS intraperitoneally. Mice were treated with antibiotics, fecal microbiota transplantation (FMT), and intratracheal administration of recombinant protein S100A4. Changes in body weight of mice were recorded, and lung injury were assessed. Then lung tissue wet/dry weight was calculated. We found knockout of FcnA, but not FcnB, alleviated sepsis-induced severe ALI evidenced by increased body weight change, decreased wet/dry weight of lung tissue, reduced inflammatory infiltration, decreased lung damage score, decreased Muc-2, TNF-α, IL-1β, IL-6, and Cr levels, and increased sIgA levels. Furthermore, knockout of FcnA restored gut microbiota homeostasis in mice. Correlation analysis showed that Akkermansia was significantly negatively associated with TNF-α, IL-1β, and IL-6 levels in serum and bronchoalveolar lavage fluid (BALF). Moreover, knockout of FcnA regulated gut microbiota to protect ALI through S100A4. Finally, we found knockout of FcnA alleviated ALI by inhibiting S100A4 via gut Akkermansia in mice, which may provide further insights and new targets into treating sepsis-induced severe lung injury.

Baicalin ameliorates multidrug-resistant Pseudomonas aeruginosa induced pulmonary inflammation in rat via arginine biosynthesis

Multidrug-resistance (MDR) Pseudomonas aeruginosa (P. aeruginosa) is a lethal gram-negative pathogen causing hospital-acquired and ventilator-associated pneumonia, which is difficult to treat. Our previous studies confirmed that baicalin, an essential bioactive component in Scutellaria baicalensis Georgi, exhibited anti-inflammatory effects in an acute pneumonia rat model induced by MDR P. aeruginosa. However, this effect of baicalin in constrast its low bioavailability, and its mechanism of action is still unknown. Thus, this study investigated whether the therapeutic effects of baicalin against MDR P. aeruginosa acute pneumonia are owing to the regulation of gut microbiota and their metabolites using pyrosequencing of the 16S rRNA genes in rat feces and metabolomics. As a result, baicalin attenuated the inflammation by acting directly on neutrophils and regulated the production of the inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-10. The mechanisms were through down-regulation of TLR4 and inhibition of NF-κB. Furthermore, pyrosequencing of the 16S rRNA genes in rat feces revealed that baicalin regulated the composition of gut microbial communities. At the genus level, baicalin efficiently increased the abundance of Ligilactobacillus, Lactobacillus and Bacteroides, but decreased the abundance of Muribaculaceae and Alistipes. Further, arginine biosynthesis was analyzed as the core pathway regulated by baicalin via combination with predicting gut microbiota function and targeted metabolomics. In conclusion, this study has demonstrated that baicalin relieved inflammatory injury in acute pneumonia rat induced by MDR P. aeruginosa via arginine biosynthesis associated with gut microbiota. Baicalin could be a promising and effective adjunctive therapy for lung inflammation caused by MDR P. aeruginosa infection.

Vunakizumab-IL22, a Novel Fusion Protein, Promotes Intestinal Epithelial Repair and Protects against Gut Injury Induced by the Influenza Virus

Secondary immune damage to the intestinal mucosa due to an influenza virus infection has gained the attention of investigators. The protection of the intestinal barrier is an effective means of improving the survival rate in cases of severe pneumonia. We developed a fusion protein, Vunakizumab-IL22(vmab-IL22), by combining an anti-IL17A antibody with IL22. Our previous study showed that Vunakizumab-IL22 repairs the pulmonary epithelial barrier in influenza virus-infected mice. In this study, we investigated the protective effects against enteritis given its anti-inflammatory and tissue repair functions. The number of goblet cells and the expression of zonula occludens protein 1(ZO-1), Mucin-2, Ki67 and IL-22R were determined by immunohistochemistry (IHC) and quantitative RT-PCR in influenza A virus (H1N1)-infected mice. The expression of NOD-like receptor pyrin domain containing 3 (NLRP3) and toll- like-receptor-4 (TLR4) was assayed by IHC in the lungs and intestine in HIN1 virus-induced mice to evaluate the whole efficacy of the protective effects on lungs and intestines. Consequently, Cytochrome C, phosphorylation of nuclear factor NF-kappaB (p-NF-κB), IL-1β, NLRP3 and Caspase 3 were assayed by Western blotting in dextran sulfate sodium salt (DSS)-treated mice. Treatment with Vunakizumab-IL22 improved the shortened colon length, macroscopic and microscopic morphology of the small intestine (p < 0.001) significantly, and strengthened the tight junction proteins, which was accompanied with the upregulated expression of IL22R. Meanwhile, Vunakizumab-mIL22 inhibited the expression of inflammation-related protein in a mouse model of enteritis induced by H1N1 and DSS. These findings provide new evidence for the treatment strategy for severe viral pneumonia involved in gut barrier protection. The results suggest that Vunakizumab-IL22 is a promising biopharmaceutical drug and is a candidate for the treatment of direct and indirect intestinal injuries, including those induced by the influenza virus and DSS.