Host tp53 mutation induces gut dysbiosis eliciting inflammation through disturbed sialic acid metabolism

The physiological characteristics and applications of sialic acid

Sialic acid (SA) is widely present at the end of the sugar chain of glycoproteins and glycolipids on the surface of animal and microbial cells and is involved in many physiological activities between microbial and host cells. Notably, these functions are attributed to the diversity of these SA types, their different transformation pathways, and their metabolic actions within the host, which are considered potential targets for affecting various diseases. However, developing disease mitigation strategies is often limited by an unclear understanding of the mechanisms of interaction of the causative agents with their hosts. This review mainly focuses on three types of SA: Neu5Ac, Neu5Gc, and KDN. The sources, main types, and distribution of these SAs are discussed in detail, emphasizing the metabolic processes of different SAs and their interaction mechanisms with the host. This review will help lay a foundation for developing functional foods and SA-targeted intervention strategies.

Structure-Based Modeling of the Gut Bacteria-Host Interactome Through Statistical Analysis of Domain-Domain Associations Using Machine Learning

The gut microbiome, a complex ecosystem of microorganisms, plays a pivotal role in human health and disease. The gut microbiome's influence extends beyond the digestive system to various organs, and its imbalance is linked to a wide range of diseases, including cancer and neurodevelopmental, inflammatory, metabolic, cardiovascular, autoimmune, and psychiatric diseases. Despite its significance, the interactions between gut bacteria and human proteins remain understudied, with less than 20,000 experimentally validated protein interactions between the host and any bacteria species. This study addresses this knowledge gap by predicting a protein-protein interaction network between gut bacterial and human proteins. Using statistical associations between Pfam domains, a comprehensive dataset of over one million experimentally validated pan-bacterial-human protein interactions, as well as inter- and intra-species protein interactions from various organisms, were used for the development of a machine learning-based prediction method to uncover key regulatory molecules in this dynamic system. This study's findings contribute to the understanding of the intricate gut microbiome-host relationship and pave the way for future experimental validation and therapeutic strategies targeting the gut microbiome interplay.

Interactions between microbiota and uterine corpus endometrial cancer: A bioinformatic investigation of potential immunotherapy

Microorganisms in the gut and other niches may contribute to carcinogenesis while also altering cancer immune surveillance and therapeutic response. However, determining the impact of genetic variations and interplay with intestinal microbes' environment is difficult and unanswered. Here, we examined the frequency of thirteen mutant genes that caused aberrant gut in thirty different types of cancer using The Cancer Genomic Atlas (TCGA) database. Substantially, our findings show that all these mutated genes are quite frequent in uterine corpus endometrial cancer (UCEC). Further, these mutant genes are implicated in the infiltration of different subset of immune cells within the Tumor Microenvironment (TME) of UCEC patients. The top-ranking mutant genes that promote immune cell invasion into the TME of UCEC patients were PGLYRP2, OLFM4, and TLR5. In this regard, we used the same deconvolution of the TCGA database to analyze the microbiome that have a strong association with immune cells invasion with TME of UCEC patients. Several bacteria and viruses have been linked to the invasion of immune cells, such as B cell memory and T cell regulatory (Tregs), into the TME of UCEC patients. As a result, our findings pave the way for future research into generating novel immunizations against bacteria or viruses as immunotherapy for UCEC patients.

Elevated muramyl dipeptide by sialic acid-facilitated postantibiotic pathobiont expansion contributes to gut dysbiosis-induced mastitis in mice

INTRODUCTION

In responses to antibiotics exposure, gut dysbiosis is a risk factor not only for pathogen infection but also for facilitating pathobiont expansion, resulting in increased inflammatory responses in the gut and distant organs. However, how this process is regulated has not been fully elucidated.

OBJECTIVES

In this study, we investigated the role of sialic acid, a host-derived carbohydrate, in the pathogenesis of gut dysbiosis-derived inflammation in distant organs.

METHODS

Ampicillin (Amp)-induced gut dysbiotic mice were treated with N-glycolylneuraminic acid (Neu5Gc) and N-acetylneuraminic acid (Neu5Ac) for three weeks to assess the role of sialic acids in mastitis. The underlying mechanism by which sialic acids regulate mastitis was explored using 16S rRNA sequencing, transcriptomics and employed multiple molecular approaches.

RESULTS

Administration of Neu5Ac and Neu5Gc exacerbated gut dysbiosis-induced mastitis and systemic inflammation. The gut dysbiosis caused by Amp was also aggravated by sialic acid. Notably, increased Enterococcus expansion, which was positively correlated with inflammatory markers, was observed in both Neu5Ac- and Neu5Gc-treated gut dysbiotic mice. Treatment of mice with Enterococcus cecorum (E. cecorum) aggravated gut dysbiosis-induced mastitis. Mechanically, sialic acid-facilitated E. cecorum expansion promoted muramyl dipeptide (MDP) release, which induced inflammatory responses by activating the NOD2-RIP2-NF-κB axis.

CONCLUSIONS

Collectively, our data reveal a role of sialic acid-facilitated postantibiotic pathobiont expansion in gut dysbiosis-associated inflammation, highlighting a potential strategy for disease prevention by regulating the MDP-NOD2-RIP2 axis.

JinLiDa granules alleviates cardiac hypertrophy and inflammation in diabetic cardiomyopathy by regulating TP53

BACKGROUND

JinLiDa granules (JLD) is a traditional Chinese medicine (TCM) used to treat type 2 diabetes mellitus with Qi and Yin deficiency. Clinical evidence has shown that JLD can alleviate diabetic cardiomyopathy, but the exact mechanism is not yet clear.

PURPOSE

The purpose of this study was to examine the potential role and mechanism of JLD in the treatment of diabetic cardiomyopathy through network pharmacological analysis and basic experiments.

METHODS

The targets of JLD associated with diabetic cardiomyopathy were examined by network pharmacology. Protein interaction analysis was performed on the targets, and the associated pathways were searched by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Diabetic mice were treated with low or high doses of JLD by gavage, and AC16 and H9C2 cardiomyocytes exposed to high-glucose conditions were treated with JLD. The analysis results were verified by various experimental techniques to examine molecular mechanisms.

RESULTS

Network pharmacological analysis revealed that JLD acted on the tumor suppressor p53 (TP53) during inflammation and fibrosis associated with diabetic cardiomyopathy. The results of basic experiments showed that after JLD treatment, ventricular wall thickening in diabetic mouse hearts was attenuated, cardiac hypertrophy and myocardial inflammation were alleviated, and the expression of cardiac hypertrophy- and inflammation-related factors in cardiomyocytes exposed to a high-glucose environment was decreased. Cardiomyocyte morphology also improved after JLD treatment. TP53 expression and the tumor necrosis factor (TNF) and transforming growth factor beta-1 (TGFβ1) signaling pathways were significantly altered, and inhibiting TP53 expression effectively alleviated the activation of the TNF and TGFβ1 signaling pathways under high glucose conditions. Overexpression of TP53 activated these signaling pathways.

CONCLUSIONS

JLD acted on TP53 to regulate the TNF and TGFβ1 signaling pathways, effectively alleviating cardiomyocyte hypertrophy and inflammation in high glucose and diabetic conditions. Our study provides a solid foundation for the future treatment of diabetic cardiomyopathy with JLD.

Picroside Ⅱ attenuates neuropathic pain by regulating inflammation and spinal excitatory synaptic transmission

Nerve injury induced microglia activation, which released inflammatory mediators and developed neuropathic pain. Picroside Ⅱ (PⅡ) attenuated neuropathic pain by inhibiting the neuroinflammation of the spinal dorsal horn; however, how it engaged in the cross talk between microglia and neurons remained ambiguous. This study aimed to investigate PⅡ in the modulation of spinal synaptic transmission mechanisms on pain hypersensitivity in neuropathic rats. We investigated the analgesia of PⅡ in mechanical and thermal hyperalgesia using the spinal nerve ligation (SNL)-induced neuropathic pain model and formalin-induced tonic pain model, respectively. RNA sequencing and network pharmacology were employed to screen core targets and signaling pathways. Immunofluorescence staining and qPCR were performed to explore the expression level of microglia and inflammatory mediator mRNA. The whole-cell patch-clamp recordings were utilized to record miniature excitatory postsynaptic currents in excitatory synaptic transmission. Our results demonstrated that the analgesic of PⅡ was significant in both pain models, and the underlying mechanism may involve inflammatory signaling pathways. PⅡ reversed the SNL-induced overexpression of microglia and inflammatory factors. Moreover, PⅡ dose dependently inhibited excessive glutamate transmission. Thus, this study suggested that PⅡ attenuated neuropathic pain by inhibiting excitatory glutamate transmission of spinal synapses, induced by an inflammatory response on microglia.

Underlying Mechanism of Traditional Herbal Formula Chuang-Ling-Ye in the Treatment of Diabetic Foot Ulcer through Network Pharmacology and Molecular Docking

BACKGROUND

Chuang-Ling-Ye (CLY) has been clinically proven to be an effective Chinese medicine for the treatment of diabetic foot ulcers (DFU).

OBJECTIVES

This study aimed to investigate the possible mechanism of CLY in relation to DFU using network pharmacology and molecular docking.

MATERIALS AND METHODS

Firstly, relevant targets of CLY against DFU were obtained from TCMSP, Swiss Target Prediction database and GEO database. Then, topological analysis was employed by Cytoscape to screen the top 6 core active ingredients and the top 8 hub targets. Furthermore, the OmicShare Tools were applied for gene ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway enrichment analysis. Finally, the results of network pharmacology were verified by molecular docking method.

RESULTS

CLY has 61 active compounds and 361 targets after de-duplication, and the top 8 hub targets were EGFR, TP53, CCND1, IL-1B, CREBBP, AR, PTGS2 and PGR. GO enrichment analysis is mainly related to signal transducer activity, receptor activity, and molecular transducer activity. KEGG pathway analysis indicated that these shared targets were primarily focused on AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, IL-17 signaling pathway, and JAK-STAT signaling pathway. Molecular docking results showed that physciondiglucoside, 2-cinnamoyl-glucose and kinobeon A were well bound with EGFR, IL-1B, AR and PTGS2.

CONCLUSION

This study demonstrated that CLY has anti-oxidative stress and anti-inflammatory effects in the treatment of DFU through various constituents, multiple targets, and multiple pathways, which provides a valuable point of reference for future investigations on CLY.

Insights into the Structure, Metabolism, Biological Functions and Molecular Mechanisms of Sialic Acid: A Review

Sialic acid (SA) is a kind of functional monosaccharide which exists widely in edible bird's nest (EBN), milk, meat, mucous membrane surface, etc. SA is an important functional component in promoting brain development, anti-oxidation, anti-inflammation, anti-virus, anti-tumor and immune regulation. The intestinal mucosa covers the microbial community that has a significant impact on health. In the gut, SA can also regulate gut microbiota and metabolites, participating in different biological functions. The structure, source and physiological functions of SA were reviewed in this paper. The biological functions of SA through regulating key signaling pathways and target genes were discussed. In summary, SA can modulate gut microbiota and metabolites, which affect gene expressions and exert its biological activities. It is helpful to provide scientific reference for the further investigation of SA in the functional foods.

Identification and verification of ferroptosis-related genes in diabetic foot using bioinformatics analysis

Ferroptosis is a novel form of cell death that plays a key role in several diseases, including inflammation and tumours; however, the role of ferroptosis-related genes in diabetic foot remains unclear. Herein, diabetic foot-related genes were downloaded from the Gene Expression Omnibus and the ferroptosis database (FerrDb). The least absolute shrinkage and selection operator regression algorithm was used to construct a related risk model, and differentially expressed genes were analysed through immune infiltration. Finally, we identified relevant core genes through a protein-protein interaction network, subsequently verified using immunohistochemistry. Comprehensive analysis showed 198 genes that were differentially expressed during ferroptosis. Based on functional enrichment analysis, these genes were primarily involved in cell response, chemical stimulation, and autophagy. Using the CIBERSORT algorithm, we calculated the immune infiltration of 22 different types of immune cells in diabetic foot and normal tissues. The protein-protein interaction network identified the hub gene TP53, and according to immunohistochemistry, the expression of TP53 was high in diabetic foot tissues but low in normal tissues. Accordingly, we identified the ferroptosis-related gene TP53 in the diabetic foot, which may play a key role in the pathogenesis of diabetic foot and could be used as a potential biomarker.

Exploring the synergistic pharmacological mechanism of Huoxiang Drink against irritable bowel syndrome by integrated data mining and network pharmacology

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder, characterized by abdominal pain, bloating, and changes in bowel habits. Huoxiang Drink (HD), derived from traditional Chinese medicine, has been reported to effectively treat digestive disorders caused by external cold and internal dampness. However, the pharmaceutical targets and mechanisms for HD against IBS remain unclear. Data mining, bioinformatics analysis, and network pharmacology were employed to explore the potential pharmacological mechanisms of HD against IBS. In this study, we screened 50 core targets to investigate the pharmacological mechanisms of HD against IBS. Enrichment analysis revealed that HD may participate in various signaling pathways, especially the inflammation-related tumor necrosis factor, signaling pathway and hypoxia-inducible factor signaling pathway. Molecular docking results confirmed that MOL000098 (Quercetin), MOL000006 (Luteolin), MOL005828 (Nobiletin), MOL005916 (Irisolidone), and MOL004328 (Naringenin), as key active ingredients in HD, bound to core targets (tumor protein P53, tumor necrosis factor, matrix metalloproteinases 9, and vascular endothelial growth factor-A) for topical treatment of IBS. This study suggested that HD offered a potential therapeutic strategy against IBS. Our findings may facilitate the efficient screening of active ingredients in HD and provide a theoretical basis for further validating the clinical therapeutic effects of HD on treating IBS.

Secreted Akkermansia muciniphila threonyl-tRNA synthetase functions to monitor and modulate immune homeostasis

Commensal bacteria are critically involved in the establishment of tolerance against inflammatory challenges, the molecular mechanisms of which are just being uncovered. All kingdoms of life produce aminoacyl-tRNA synthetases (ARSs). Thus far, the non-translational roles of ARSs have largely been reported in eukaryotes. Here, we report that the threonyl-tRNA synthetase (AmTARS) of the gut-associated bacterium Akkermansia muciniphila is secreted and functions to monitor and modulate immune homeostasis. Secreted AmTARS triggers M2 macrophage polarization and orchestrates the production of anti-inflammatory IL-10 via its unique, evolutionary-acquired regions, which mediates specific interactions with TLR2. This interaction activates the MAPK and PI3K/AKT signaling pathways, which converge on CREB, leading to an efficient production of IL-10 and suppression of the central inflammatory mediator NF-κB. AmTARS restores IL-10-positive macrophages, increases IL-10 levels in the serum, and attenuates the pathological effects in colitis mice. Thus, commensal tRNA synthetases can act as intrinsic mediators that maintain homeostasis.

Clonal hematopoiesis and bone marrow inflammation

Clonal hematopoiesis (CH) occurs in hematopoietic stem cells with increased risks of progressing to hematologic malignancies. CH mutations are predominantly found in aged populations and correlate with an increased incidence of cardiovascular and other diseases. Increased lines of evidence demonstrate that CH mutations are closely related to the inflammatory bone marrow microenvironment. In this review, we summarize the recent advances in this topic starting from the discovery of CH and its mutations. We focus on the most commonly mutated and well-studied genes in CH and their contributions to the innate immune responses and inflammatory signaling, especially in the hematopoietic cells of bone marrow. We also aimed to discuss the interrelationship between inflammatory bone marrow microenvironment and CH mutations. Finally, we provide our perspectives on the challenges in the field and possible future directions to help understand the pathophysiology of CH.

Sialic acid exacerbates gut dysbiosis-associated mastitis through the microbiota-gut-mammary axis by fueling gut microbiota disruption

BACKGROUND

Mastitis is one of the most severe diseases in humans and animals, especially on dairy farms. Mounting evidence indicates that gastrointestinal dysbiosis caused by induction of subacute ruminal acidosis (SARA) by high-grain diet consumption and low in dietary fiber is associated with mastitis initiation and development, however, the underlying mechanism remains unknown.

RESULTS

In the present study, we found that cows with SARA-associated mastitis have altered metabolic profiles in the rumen, with increased sialic acids level in particular. Consumption of sialic acid (SA) in antibiotic-treated mice, but not healthy mice, induced marked mastitis. SA treatment of antibiotic-treated mice also induced mucosal and systemic inflammatory responses, as evidenced by increased colon and liver injuries and several inflammatory markers. In addition, gut dysbiosis caused by antibiotic impaired gut barrier integrity, which was aggravated by SA treatment. SA potentiated serum LPS level caused by antibiotic treatment, leading to increased activation of the TLR4-NF-κB/NLRP3 pathways in the mammary gland and colon. Moreover, SA facilitated gut dysbiosis caused by antibiotic, and especially enhanced Enterobacteriaceae and Akkermansiaceae, which correlated with mastitis parameters. Fecal microbiota transplantation from SA-antibiotic-treated mice mimicked mastitis in recipient mice. In vitro experiments showed that SA prompted Escherichia coli growth and virulence gene expression, leading to higher proinflammatory cytokine production in macrophages. Targeting the inhibition of Enterobacteriaceae by sodium tungstate or treating with the commensal Lactobacillus reuteri alleviated SA-facilitated mastitis. In addition, SARA cows had distinct ruminal microbial structure by the enrichment of SA-utilizing opportunistic pathogenic Moraxellaceae and the depletion of SA-utilizing commensal Prevotellaceae. Treating mice with the specific sialidase inhibitor zanamivir reduced SA production and Moraxellaceae abundance, and improved mastitis in mice caused by ruminal microbiota transplantation from cows with SARA-associated mastitis.

CONCLUSIONS

This study, for the first time, indicates that SA aggravates gut dysbiosis-induced mastitis by promoting gut microbiota disturbance and is regulated by commensal bacteria, indicating the important role of the microbiota-gut-mammary axis in mastitis pathogenesis and suggesting a potential strategy for mastitis intervention based on gut metabolism regulation. Video Abstract.

Application of zebrafish in the study of the gut microbiome

Zebrafish (Danio rerio) have attracted much attention over the past decade as a reliable model for gut microbiome research. Owing to their low cost, strong genetic and development coherence, efficient preparation of germ-free (GF) larvae, availability in high-throughput chemical screening, and fitness for intravital imaging in vivo, zebrafish have been extensively used to investigate microbiome-host interactions and evaluate the toxicity of environmental pollutants. In this review, the advantages and disadvantages of zebrafish for studying the role of the gut microbiome compared with warm-blooded animal models are first summarized. Then, the roles of zebrafish gut microbiome on host development, metabolic pathways, gut-brain axis, and immune disorders and responses are addressed. Furthermore, their applications for the toxicological assessment of aquatic environmental pollutants and exploration of the molecular mechanism of pathogen infections are reviewed. We highlight the great potential of the zebrafish model for developing probiotics for xenobiotic detoxification, resistance against bacterial infection, and disease prevention and cure. Overall, the zebrafish model promises a brighter future for gut microbiome research.