A high-fiber diet synergizes with Prevotella copri and exacerbates rheumatoid arthritis

Exposure to polyethylene terephthalate micro(nano)plastics exacerbates inflammation and fibrosis after myocardial infarction by reprogramming the gut and lung microbiota and metabolome

Micro(nano)plastics (MNPs), a ubiquitous environmental pollutant, have received increasing attention for their impacts on human health. We conducted an in-depth study on the role of polyethylene terephthalate (PET) MNPs in myocardial infarction (MI). Blood from the coronary circulation of MI patients was collected to detect microplastics (MPs). Peripheral monocytes (PBMCs) and AC16 cells were used to assess inflammation, cell proliferation and apoptosis after PET nanoplastics (NPs) stimulation. The mouse MI model was established after PET NPs respiratory or oral exposure. The results showed that various types of MPs, including high levels of PET MPs, were detected in the coronary circulation. PET NPs promoted inflammatory factors secretion by PBMCs, inhibited AC16 cell proliferation and promoted hypoxia-induced AC16 cell apoptosis. PET NPs exacerbated post-MI inflammation and fibrosis through activating the NLRP3 inflammasome pathway. Through macrogenetic sequencing and metabolomics analyses, we observed that PET NPs reprogrammed the intestinal and lung microbiota and metabolome in MI mice, leading to chronic inflammation. In conclusion, PET MPs were widely present in the coronary circulation of MI patients. PET MNPs can activate the NLRP3 inflammasome pathway to exacerbate post-MI ventricular remodelling, which may be related to the reprogramming of the gut and lung microbiota and metabolome.

Animal Models Informing the Role of the Microbiome and its Metabolites in Rheumatoid Arthritis

Animal models of rheumatoid arthritis (RA) are essential for understanding the disease's mechanisms and developing new treatments. Recent research highlights the microbiome's significant roles in RA pathogenesis, influencing disease susceptibility and progression. These models allow researchers to investigate the causal relationships between specific microbial species and arthritis development. Despite challenges in translating findings to human conditions, animal models are crucial for uncovering microbiome-related therapeutic strategies, advancing our understanding of RA, and improving patient outcomes.

MTX-induced gastrointestinal reactions in RA: Prevotella enrichment, gut dysbiosis, and PI3K/Akt/Ras/AMPK pathways

OBJECTIVES

To investigate the role of gut microbiota in methotrexate (MTX)-induced gastrointestinal reactions (MRGR) in patients with rheumatoid arthritis (RA).

METHODS

As a prospective, single-center, convenience sampling study, stool samples were obtained from 28 RA patients (male: female = 10:18) at Lanzhou University Second Hospital who were undergoing MTX treatment for analysis of their gut microbiota using 16S rRNA gene sequencing. Clinical disease activity (CDAI) and MRGR were assessed after two months of MTX therapy. All data collection periods exceeded one year. Intestinal germ-free mice, generated through antibiotic treatment, received fecal microbiota transplantation (FMT) from the patients, followed by varying doses of MTX to observe MRGR. Intestinal transcriptomics and markers related to intestinal barrier function were subsequently examined.

RESULTS

Females (84.6%) and high disease activity (CDAI scores, 39.6 ± 11.2 vs 26.3 ± 9.2) were prone to have MRGR in RA patients. Patients with MRGR (PT-GR) showed lower gut microbial diversity versus non-MRGR (PT-noGR). Prevotella abundance, positively correlated with CDAI and MRGR (p < 0.05), was elevated in PT-GR. Administering 10 mg/kg MTX to mice caused intestinal damage. FMT-GR-MTX mice exhibited weight loss (95.2%), morphological deterioration (86.4%), and reduced tight junction proteins (Claudin-1:72.4%; ZO-1:81.2%). Transcriptomics linked upregulated Gβγ/CREB/Atp4b to PI3K/Akt/Ras pathways and downregulated PFK2/PP2 to AMPK signaling in MRGR.

CONCLUSION

Our study identified notable gut microbiota alterations in RA patients prone to MRGR, with changes in intestinal gene expression and reduced intestinal barrier function potentially contributing to MRGR. These findings suggest potential strategies to mitigate MRGR in RA patients undergoing MTX treatment. Key Points • The RA-related MRGR is correlated with the intestinal microbiota. • Females, low gut diversity, and Prevotella enrichment are MRGR risks in RA. • Upregulated DEGs in MRGR linked to PI3K/Akt, Ras pathways. • Downregulated DEGs in MRGR focus on the AMPK pathway.

Gut prevotella copri abundance linked to elevated post-exercise inflammation

PURPOSE

This study aimed to examine the linkage between gut microbiome taxa and exercise-induced inflammation.

METHODS

Twenty-five cyclists provided 4 stool samples during a 10-week period and cycled vigorously for 2.25 h at 67% maximal oxygen uptake (VO2max) in a laboratory setting. Blood samples were collected pre- and post-exercise, with additional samples collected at 1.5 h-, 3 h-, and 24 h-post-exercise. Primary outcomes included stool microbiome composition and alpha diversity via whole genome shotgun (WGS) sequencing (averaged from 4 stool samples) and a targeted panel of 75 plasma oxylipins. A total of 5719 taxa were identified, and the 339 that were present in more than 20% of stool samples were used in the analysis. Alpha diversity was calculated by evenness, and the Analysis of Composition of Microbiomes (ANCOM) differential abundance analysis was performed using QIIME2. A composite variable was calculated from 8 pro-inflammatory oxylipins generated from arachidonic acid (ARA) and cytochrome P-450 (CYP).

RESULTS

ARA-CYP oxylipins were significantly elevated for at least 3 h post-exercise (p < 0.001); they were strongly and positively related to Prevotella copri (P. copri) abundance (R2 = 0.676, p < 0.001) and negatively related to gut microbiome alpha diversity (R2 = 0.771, p < 0.001).

CONCLUSION

This analysis revealed for the first time a novel, positive relationship between gut microbiome P. copri abundance in cyclists and post-exercise pro-inflammatory oxylipins. These data demonstrate that about two-thirds of the wide variance in inflammation following prolonged and intensive exercise is largely explained by the abundance of a single gut bacterial species: P. copri.

Exploring effects of gut microbiota on tertiary lymphoid structure formation for tumor immunotherapy

Anti-tumor immunity, including innate and adaptive immunity is critical in inhibiting tumorigenesis and development of tumor. The adaptive immunity needs specific lymph organs such as tertiary lymphoid structures (TLSs), which are highly correlated with improved survival outcomes in many cancers. In recent years, with increasing attention on the TLS in tumor microenvironment, TLSs have emerged as a novel target for anti-tumor therapy. Excitingly, studies have shown the contribution of TLSs to the adaptive immune responses. However, it is unclear how TLSs to form and how to more effectively defense against tumor through TLS formation. Recent studies have shown that the inflammation plays a critical role in TLS formation. Interestingly, studies have also found that gut microbiota can regulate the occurrence and development of inflammation. Therefore, we here summarize the potential effects of gut microbiota- mediated inflammation or immunosuppression on the TLS formation in tumor environments. Meanwhile, this review also explores how to manipulate mature TLS formation through regulating gut microbiota/metabolites or gut microbiota associated signal pathways for anti-tumor immunity, which potentially lead to a next-generation cancer immunotherapy.

New thoughts on the gut-immune axis of arthritis

Arthritis is associated with varying degrees of intestinal inflammation and microbiota dysbiosis, leading to the 'gut-joint axis hypothesis' in which intestinal and joint inflammation are suggested to be interconnected through immune-microbiota interactions. While clinical observations support this, causality remains uncertain. Rodent models have provided insights into potential mechanisms by uncovering microbial influences and immune pathways that either connect or uncouple gut and joint inflammation. Based on recent findings, we propose the 'immune hypersensitivity hypothesis' whereby central immune hyper-reactivity can independently drive joint inflammation via local sterile triggers, and gut inflammation via microbial triggers. We argue that this suggests a more nuanced role of the microbiota in arthritis pathogenesis that varies according to the predominant immune mechanisms in disease subtypes. We explore gut-immune interactions in arthritis, highlight ongoing challenges, and propose future research directions.

Microbiota and immune dynamics in rheumatoid arthritis: Mechanisms and therapeutic potential

Rheumatoid arthritis (RA) is a complex autoimmune disease with growing evidence implicating the microbiota as a critical contributor to its pathogenesis. This review explores the multifaceted roles of microbial dysbiosis in RA, emphasizing its impact on immune cell modulation, autoantibody production, gut barrier integrity, and joint inflammation. Animal models reveal how genetic predisposition and environmental factors interact with specific microbial taxa to influence disease susceptibility. Dysbiosis-driven metabolic disruptions, including alterations in short-chain fatty acids and bile acids, further exacerbate immune dysregulation and systemic inflammation. Emerging therapeutic strategies-probiotics, microbial metabolites, fecal microbiota transplantation, and antibiotics-offer innovative avenues for restoring microbial balance and mitigating disease progression. By integrating microbiota-targeted approaches with existing treatments, this review highlights the potential to revolutionize RA management through precision medicine and underscores the need for further research to harness the microbiota's therapeutic potential.

Dynamic human gut microbiome and immune shifts during an immersive psychosocial intervention program

BACKGROUND

Although depression is a leading cause of disability worldwide, the pathophysiological mechanisms underlying this disorder-particularly those involving the gut microbiome-are poorly understood.

METHOD

To investigate, we conducted a community-based observational study to explore complex associations between changes in the gut microbiome, cytokine levels, and depression symptoms in 51 participants (Mage = 49.56, SD = 13.31) receiving an immersive psychosocial intervention. A total of 142 multi-omics samples were collected from participants before, during, and three months after the nine-day inquiry-based stress reduction program.

RESULTS

Results revealed that depression was associated with both an increased presence of putatively pathogenic bacteria and reduced microbial beta-diversity. Following the intervention, we observed reductions in neuroinflammatory cytokines and improvements in several mental health indicators. Interestingly, participants with a Prevotella-dominant microbiome showed milder symptoms when depressed, along with a more resilient microbiome and more favorable inflammatory cytokine profile, including reduced levels of CXCL-1.

CONCLUSIONS

These findings reveal a potentially protective link between the Prevotella-dominant microbiome and depression, as evidenced by a reduced pro-inflammatory environment and fewer depressive symptoms. These insights, coupled with observed improvements in neuroinflammatory markers and mental health from the intervention, may highlight potential avenues for microbiome-targeted therapies for managing depression.

Gut microbiota and their metabolites in the immune response of rheumatoid arthritis: Therapeutic potential and future directions

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent joint inflammation, damage, and loss of function. In recent years, the role of gut microbiota and its metabolites in immune regulation has attracted increasing attention. The gut microbiota influences the host immune system's homeostasis through various mechanisms, regulating the differentiation, function, and immune tolerance of immune cells. Dysbiosis of the gut microbiota in RA patients is closely associated with abnormal activation of immune cells and excessive secretion of inflammatory cytokines. Metabolites produced by the gut microbiota, such as short-chain fatty acids (SCFAs), tryptophan metabolites, bile acids, and amino acid metabolites, play a critical role in immune responses, regulating the functions of immune cells like T cells, B cells, and macrophages, and inhibiting the release of pro-inflammatory cytokines. Restoring the balance of the gut microbiota and optimizing the production of metabolic products may become a new strategy for RA treatment. This review discusses the role of gut microbiota and its metabolites in the immune response of RA, exploring how they influence the immunopathological process of RA through the regulation of immune cells and key immune factors. It also provides a theoretical basis for future therapeutic strategies based on gut microbiota modulation.

Roles of Probiotics, Prebiotics, and Postbiotics in B-Cell-Mediated Immune Regulation

Probiotics, prebiotics, and postbiotics can significantly influence B-cell-related diseases through their immunomodulatory effects. They enhance the immune system's function, particularly affecting B cells, which originate in the bone marrow and are crucial for antibody production and immune memory. These substances have therapeutic potential in managing allergies, autoimmune diseases, and inflammatory conditions by regulating the gut microbiota, strengthening epithelial barriers, and directly interacting with various components of the innate and adaptive immune systems. The review highlights the critical need for further research into the precise mechanisms through which probiotics, prebiotics, and postbiotics modulate B cells. Gaining this understanding could facilitate the development of more effective treatments for B-cell-related diseases by harnessing the immunomodulatory properties of these dietary components.

Cannabidiol regulates L-carnitine and butyric acid metabolism by modulating the gut microbiota to ameliorate collagen-induced arthritis

BACKGROUND

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases, affecting multiple systems in the body. Cannabidiol (CBD) is one of the most medically valuable active ingredients in cannabis. At present, CBD has been shown to alleviate the progression of RA; however, owing to its multiple targets, the mechanism of CBD is not clear.

METHODS

On the basis of the gut microbiota, we explored the mechanism by which CBD inhibits RA progression. Metagenomic and nontargeted metabolomic analyses were used to determine the changes in the intestinal ecology and plasma metabolites of collagen-induced arthritis (CIA) rats after CBD treatment.

RESULTS

CBD reversed gut dysbiosis in CIA rats, notably altering the abundances of Allobaculum_unclassified, Allobaculum_fili, and Prevotella_unclassified. In addition, metabolomic analysis confirmed that CBD increased the contents of butyric acid and L-carnitine. Allobaculum could produce butyric acid and Prevotella could accelerate the metabolism of L-carnitine. In addition, in vitro experiments demonstrated that L-carnitine participated in the regulation of neutrophils, macrophages and RA-fibroblast-like synoviocytes (RA-FLSs), which was consistent with the synovial changes in CIA rats caused by CBD.

CONCLUSION

In summary, CBD increased the plasma contents of butyric acid and L-carnitine by altering the abundances of gut microbiota, thereby inhibiting inflammation in neutrophils, macrophages and RA-FLSs. Our study is the first to explain the mechanism by which CBD alleviates progression in CIA rats from the perspective of gut microbes and metabolites, providing new views into CBD mechanisms, which warrants clinical attention.

Guizhi Shaoyao Zhimu decoction inhibits neutrophil extracellular traps formation to relieve rheumatoid arthritis via gut microbial outer membrane vesicles

BACKGROUND

Rheumatoid arthritis (RA) is a common autoimmune disease with a high disability rate. Accumulating studies suggest that neutrophil extracellular traps (NETs) play a crucial role in the pathogenesis of RA and targeting NETs has emerged as a potential therapeutic strategy for RA. As a traditional Chinese medicine, Guizhi-Shaoyao-Zhimu Decoction (GSZD) has exhibited good efficacy in the treatment of rheumatoid arthritis (RA), while the underly mechanism especially the possibility that GSZD alter NETs formation to relieve RA remains unknown.

PURPOSE

Our study aimed to investigate relationship between GSZD and NETs in RA treatment and revealed underlying mechanism.

METHODS

We constructed collagen-induced arthritis (CIA) model and treated CIA mice with GZSY to validate therapeutic effects of GSZD and examine whether GZSD could inhibit NETs formation in RA. And 16S rRNA sequencing and Fecal microbiota transplantation (FMT) experiment were performed to determine whether GSZD could reduce NETs formation to alleviate RA in gut microbiota-associated manner and identify crucial bacterium in response to GSZD administration. CIA mice treated with effective bacteria and its outer membrane vesicles (OMVs) with oral administration to investigate protective effect against RA and NETs regulative efficiency. We utilized small interfering RNA in vivo and vitro to silence gene mediating effect of GZSD-gut microbiota-NETs.

RESULTS

GSZD could inhibit NETs formation and relive arthritis in CIA mice. Additionally, GSZD alter gut microbiota composition and significantly increase intestinal Parabacteroides goldsteinii (P.goldsteinii) abundance. Mechanistically, P.goldsteinii enriched by GSZD secreted outer membrane vesicles (OMVs) to translocate into joints and activate Cav-1-Nrf2 axis, leading to reduced NETs formation and alleviate arthritis. In clinical, the abundance of P.goldsteinii exhibited negative correlation with NETs indexes and RA disease activities.

CONCLUSION

Our findings suggest that GSZD inhibits NETs formation to relieve RA in P.goldsteinii-Cav-1-Nrf2 associated manner, which could provide new sight of the prevention and treatment of RA.

The comprehensive relationship between combined anti-inflammatory and healthy diets and all-cause mortality in rheumatoid arthritis: results from NHANES 2003-2018

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disorder. Diet is recognized as a modifiable factor that may influence inflammation and potentially accelerate RA progression. Nevertheless, the effects of diverse dietary patterns and their combined impact on RA progression and long-term mortality remain inadequately understood. This study examined the association between dietary patterns and mortality in patients with RA, focusing on the Healthy Eating Index (HEI-2015) and Dietary Inflammatory Index (DII) and evaluating their combined effects.

METHODS

The analysis included 2,069 patients with RA from the National Health and Nutrition Examination Survey (NHANES) spanning 2003-2018. Weighted multi-variable Cox regression models estimated the relationship between the DII, HEI-2015, combined dietary patterns, and all-cause mortality in patients with RA. Linear associations between the DII, HEI-2015, and all-cause mortality were analyzed using restricted cubic splines (RCS). Dietary factors associated with mortality were identified through the Least Absolute Shrinkage and Selection Operator (LASSO) method, and subgroup and sensitivity analyses were conducted to strengthen the findings.

RESULTS

Participants had a median age of 59 years (IQR: 48-69), with 42.1% male. Adjusting for potential confounders, the hazard ratio (HR) for individuals adhering to healthy and anti-inflammatory dietary patterns, as opposed to unhealthy and pro-inflammatory patterns, was 0.70 (95% CI: 0.53-0.92; adjusted P = 0.01; trend P = 0.02). In weighted Cox analyses of the DII and HEI-2015, higher quartiles showed no significant mortality risk difference from the lowest quartiles. The LASSO-Cox model identified 12 dietary components predictive of all-cause mortality in patients with RA, with an AUC of 0.749 (0.682-0.815) at 1 year, 0.763 (0.724-0.802) at 3 years, 0.783 (0.749-0.802) at 5 years, and 0.868 (0.712-0.938) for all death events. Kaplan-Meier analysis revealed that the low-risk dietary group exhibited significantly lower mortality compared to the high-risk group (P < 0.001).

CONCLUSIONS

These findings suggest that combining a higher HEI-2015 with a lower DII score correlates with reduced all-cause mortality risk among patients with RA, supporting dietary modification as a potential strategy to prevent premature death in this population.

Elucidating the role of gut microbiota metabolites in diabetes by employing network pharmacology

BACKGROUND

Extensive research has underscored the criticality of preserving diversity and equilibrium within the gut microbiota for optimal human health. However, the precise mechanisms by which the metabolites and targets of the gut microbiota exert their effects remain largely unexplored. This study utilizes a network pharmacology methodology to elucidate the intricate interplay between the microbiota, metabolites, and targets in the context of DM, thereby facilitating a more comprehensive comprehension of this multifaceted disease.

METHODS

In this study, we initially extracted metabolite information of gut microbiota metabolites from the gutMGene database. Subsequently, we employed the SEA and STP databases to discern targets that are intricately associated with these metabolites. Furthermore, we leveraged prominent databases such as Genecard, DisGeNET, and OMIM to identify targets related to diabetes. A protein-protein interaction (PPI) network was established to screen core targets. Additionally, we conducted comprehensive GO and KEGG enrichment analyses utilizing the DAVID database. Moreover, a network illustrating the relationship among microbiota-substrate-metabolite-target was established.

RESULTS

We identified a total of 48 overlapping targets between gut microbiota metabolites and diabetes. Subsequently, we selected IL6, AKT1 and PPARG as core targets for the treatment of diabetes. Through the construction of the MSMT comprehensive network, we discovered that the three core targets exert therapeutic effects on diabetes through interactions with 8 metabolites, 3 substrates, and 5 gut microbiota. Additionally, GO analysis revealed that gut microbiota metabolites primarily regulate oxidative stress, inflammation and cell proliferation. KEGG analysis results indicated that IL-17, PI3K/AKT, HIF-1, and VEGF are the main signaling pathways involved in DM.

CONCLUSION

Gut microbiota metabolites primarily exert their therapeutic effects on diabetes through the IL6, AKT1, and PPARG targets. The mechanisms of gut microbiota metabolites regulating DM might involve signaling pathways such as IL-17 pathways, HIF-1 pathways and VEGF pathways.

Photoelectrocatalytic degradation of hyaluronic acid and regulation effects of its degradation products on gut microbiota in vitro

Hyaluronic acid (HA) has multiple biological activities which are closely related to its molecular weight. In the present study, the photoelectrocatalytic method was established for HA degradation and the influences of bias potentials, H2O2 additions and reaction times on the degradation results were investigated to optimize the reaction condition. Moreover, a series of analysis methods, such as FT-IR and NMR were used to analyze chemical compositions of the degradation products, revealing that photoelectrocatalytic degradation did not damage the structural blocks of HA obviously. Then 11 oligosaccharides with polymerization degrees from 2 to 8 in the degradation products were identified by mass spectroscopy and their reducing ends were all GlcA or AraA. In addition, in the photoelectrocatalytic degradation of HA, ·OH were identified as the most influential among the produced free radicals, and it could be proposed that ·OH specifically targeted the anomeric carbon of GlcA, resulting in the disaggregation of polysaccharides chain. Furthermore, the results of in vitro fermentation with fecal microbiota demonstrated that HA and its degradation products regulated microbiota structure discriminately, indicating their possible different outcomes as nutritional supplements and agents.

Licorice-regulated gut-joint axis for alleviating collagen-induced rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is partially affected by the integrity of the intestinal barrier. Licorice (GC), a medicinal and food-related herb, exhibits potent anti-inflammatory activity; however, studies on its mechanisms of action in RA are limited.

METHOD

Using a bovine type-II collagen-induced arthritis rat model, this study examined how GC influences the gut-joint axis to decrease RA. The Th17/Treg cell ratios in the blood, colon, and joints were also measured. Metabolomics and 16S rRNA sequencing were applied to explore the effects of variations in gut flora and metabolites.

RESULTS

The arthropathological slices, inflammation markers, and joint inflammation index scores in the GC treatment group significantly differed from those in the CIA group. Studies on the effect of GC on the gut-joint axis showed changes in the levels of lipopolysaccharide and diamine oxidase, both directly associated with intestinal permeability. ZO-1, occludin, and claudin-1, three intestinal tight-junction proteins, may express themselves more when exposed to GC. By maintaining an appropriate Th17/Treg cell ratio in the blood, colon, and joints, GC may reduce impaired to the intestinal barrier. An imbalance in the intestinal microenvironment, caused by modifications in gut flora and endogenous substances, can damage the intestinal barrier. GC may modify the relative abundances of Papillibacter, Clostridium, Eubacterium, Helicobacter, Provotella, and Barnesiella during RA treatment by repairing the intestinal barrier. The metabolic differences were mainly related to primary bile acid biosynthesis, pyrimidine metabolism, steroid biosynthesis, biotin metabolism, and sphingolipid metabolism. A fecal microbiota transplantation experiment confirmed the involvement of the gut microbiota and its metabolites in GC-mediated RA therapy.

CONCLUSION

The results demonstrated that GC repairs the intestinal barrier and adjusts the gut-joint axis to manage immunological imbalance in RA.

Dietary pectin and inulin: A promising adjuvant supplement for collagen-induced arthritis through gut microbiome restoration and CD4+ T cell reconstitution

Dietary strategies rich in fiber have been demonstrated to offer benefits to individuals afflicted with rheumatoid arthritis (RA). However, the specific mechanisms through which a high-fiber diet (HFD) mitigates RA's autoimmunity remain elusive. Herein, we investigate the influence of pectin- and inulin-rich HFD on collagen-induced arthritis (CIA). We establish that HFD significantly alleviates arthritis in CIA mice by regulating the Th17/Treg balance. The rectification of aberrant T cell differentiation by the HFD is linked to the modulation of gut microbiota, augmenting the abundance of butyrate in feces. Concurrently, adding butyrate to the drinking water mirrors the HFD's impact on ameliorating CIA, encompassing arthritis mitigation, regulating intestinal barrier integrity, and restoring the Th17/Treg equilibrium. Butyrate reshapes the metabolic profile of CD4+ T cells in an AMPK-dependent manner. Our research underscores the importance of dietary interventions in rectifying gut microbiota for RA management and offers an explanation of how diet-derived microbial metabolites influence RA's immune-inflammatory-reaction.

Segatella clades adopt distinct roles within a single individual's gut

Segatella is a prevalent genus within individuals' gut microbiomes worldwide, especially in non-Western populations. Although metagenomic assembly and genome isolation have shed light on its genetic diversity, the lack of available isolates from this genus has resulted in a limited understanding of how members' genetic diversity translates into phenotypic diversity. Within the confines of a single gut microbiome, we have isolated 63 strains from diverse lineages of Segatella. We performed comparative analyses that exposed differences in cellular morphologies, preferences in polysaccharide utilization, yield of short-chain fatty acids, and antibiotic resistance across isolates. We further show that exposure to Segatella isolates either evokes strong or muted transcriptional responses in human intestinal epithelial cells. Our study exposes large phenotypic differences within related Segatella isolates, extending this to host-microbe interactions.

Oral Microbiota Variations in Psoriasis Patients Without Comorbidity

Background

Psoriasis is a chronic inflammatory skin disease, and its etiology is still unclear. There is increasing evidence suggesting that microorganisms may trigger psoriasis. However, the relationship between psoriasis and oral microbiota remains poorly understood. Our aim is to identify differences in the composition and diversity of the oral microbiota between patients with psoriasis and healthy controls, and to discover oral microbial markers for assessing the severity of psoriasis.

Methods

This study recruited 20 psoriasis patients and 20 healthy individuals, collecting their saliva to analyze the composition of the oral microbiota in psoriasis patients. We employed 16S rRNA sequencing technology and utilized various methods for oral microbiome analysis, including the Shannon Index, Gini-Simpson Index, Principal Coordinates Analysis (PCoA), non-metric multidimensional scaling (NMDS), Linear discriminant analysis Effect Size (LEfSe), Wilcoxon test, and Spearman's rank correlation.

Results

The results showed that the alpha diversity of oral microbiota was higher in psoriasis patients. The relative abundances of certain bacterial taxa differed between psoriasis and healthy individuals, including Prevotella, Prevotella 7 and Porphyromonas gingivalis, which are increased in psoriasis. We also found a positive correlation between Alloprevotella, Porphyromonas, and Neisseria with the severity of psoriasis, while Veillonella showed a negative correlation.

Conclusion

In summary, this study found significant changes in the composition of the oral microbiota in patients with psoriasis. Some oral bacteria are associated with psoriasis severity. It provides a new perspective on the relationship between the oral microbiota and psoriasis.

The rheumatoid arthritis gut microbial biobank reveals core microbial species that associate and effect on host inflammation and autoimmune responses

Gut microbiota dysbiosis has been implicated in rheumatoid arthritis (RA) and influences disease progression. Although molecular and culture-independent studies revealed RA patients harbored a core microbiome and had characteristic bacterial species, the lack of cultured bacterial strains had limited investigations on their functions. This study aimed to establish an RA-originated gut microbial biobank (RAGMB) that covers and further to correlates and validates core microbial species on clinically used and diagnostic inflammation and immune indices. We obtained 3200 bacterial isolates from fecal samples of 20 RA patients with seven improved and 11 traditional bacterial cultivation methods. These isolates were phylogenetically identified and selected for RAGMB. The RAGMB harbored 601 bacterial strains that represented 280 species (including 43 novel species) of seven bacterial phyla. The RAGMB covered 93.2% at species level of medium- and high-abundant (relative abundances ≥0.2%) RA gut microbes, and included four rare species of the phylum Synergistota. The RA core gut microbiome was defined and composed of 20 bacterial species. Among these, Mediterraneibacter tenuis and Eubacterium rectale were two species that statistically and significantly correlated with clinically used diagnostic indices such as erythrocyte sedimentation rate (ESR) and IL-10. Thus, M. tenuis and E. rectale were selected for experimental validation using DSS-treated and not DSS-treated mice model. Results demonstrated both M. tenuis and E. rectale exacerbated host inflammatory responses, including shortened colon length and increased spleen weight, decreased IL-10 and increased IL-17A levels in plasma. Overall, we established the RAGMB, defined the RA core microbiome, correlated and demonstrated core microbial species effected on host inflammatory and immune responses. This work provides diverse gut microbial resources for future studies on RA etiology and potential new targets for new biomedical practices.

Gut Dysbiosis and Dietary Interventions in Rheumatoid Arthritis-A Narrative Review

Rheumatoid arthritis (RA) is a chronic and progressive autoimmune disease. The pathogenesis of RA is complex and involves interactions between articular cells, such as fibroblast-like synoviocytes, and immune cells. These cells secrete pro-inflammatory cytokines, chemokines, metalloproteinases and other molecules that together participate in joint degradation. The current evidence suggests the important immunoregulatory role of the gut microbiome, which can affect susceptibility to diseases and infections. An altered microbiome, a phenomenon known as gut dysbiosis, is associated with the development of inflammatory diseases. Importantly, the profile of the gut microbiome depends on dietary habits. Therefore, dietary elements and interventions can indirectly impact the progression of diseases. This review summarises the evidence on the involvement of gut dysbiosis and diet in the pathogenesis of RA.

Oral Supplementation with the Short-Chain Fatty Acid Acetate Ameliorates Age-Related Arterial Dysfunction in Mice

Adverse changes in the gut microbiome with aging are an emerging mediator of arterial dysfunction, which contributes to cardiovascular disease (CVD) development. We investigated the therapeutic potential of enhancing the bioavailability of gut-derived short-chain fatty acids (SCFAs; produced from dietary fiber) for improving age-related arterial dysfunction. We performed gut microbial whole-genome sequencing in young (3 months) versus old (24 months) male C57BL/6N mice to explore changes in bacterial taxonomic abundance and functional pathways with aging and relations to arterial function. We then supplemented young and old mice with the SCFA acetate in drinking water versus controls and versus a high-fiber diet for 8-10 weeks to test the effects of these interventions on vascular function and explore potential mechanisms. Of the various differences in the gut microbiomes of old mice, lower SCFA-producing capacity (taxonomic abundance and functional pathways) stood out as a key feature related to worse arterial function after adjusting for age. Acetate supplementation and a high-fiber diet reversed ~30% of the age-related increase in aortic pulse wave velocity (stiffness) and fully restored carotid artery endothelium-dependent dilation (endothelial function) to young levels. Acetate and a high-fiber diet reduced age-related increases in systemic inflammation. We also found that improvements in endothelial function were likely mediated by suppressed early growth response-1 signaling using innovative siRNA-based knockdown in isolated arteries. There were no effects of the interventions in young mice. Acetate supplementation was comparably effective for ameliorating arterial dysfunction with aging as a high-fiber diet and thus shows promise for reducing CVD risk in older adults.

Microbiota-Short Chain Fatty Acid Relationships Underlie Clinical Heterogeneity and Identify Key Microbial Targets in Irritable Bowel Syndrome (IBS)

Background

Identifying microbial targets in irritable bowel syndrome (IBS) and other disorders of gut-brain interaction (DGBI) is challenging due to the dynamic nature of microbiota-metabolite-host interactions. SCFA are key microbial metabolites that modulate intestinal homeostasis and may influence IBS pathophysiology. We aimed to assess microbial features associated with short chain fatty acids (SCFA) and determine if features varied across IBS subtypes and endophenotypes. Among 96 participants who were screened, 71 completed the study. We conducted in-depth investigations of stool microbial metagenomes, stool SCFA, and measurable IBS traits (stool bile acids, colonic transit, stool form) in 41 patients with IBS (IBS with constipation [IBS-C] IBS with diarrhea [IBS-D]) and 17 healthy controls. We used partial canonical correspondence analyses (pCCA), conditioned on transit, to quantify microbe-SCFA associations across clinical groups. To explore relationships between microbially-derived SCFA and IBS traits, we compared gut microbiome-encoded potential for substrate utilization across groups and within a subset of participants selected by their stool characteristics as well as stool microbiomes of patients with and without clinical bile acid malabsorption.

Results

Overall stool microbiome composition and individual taxa abundances differed between clinical groups. Microbes-SCFA associations differed across groups and revealed key taxa including Dorea sp. CAG:317 and Bifidobacterium pseudocatenulatum in IBS-D and Akkermansia muciniphila and Prevotella copri in IBS-C that that may drive subtype-specific microbially-mediated mechanisms. Strongest microbe-SCFA associations were observed in IBS-D and several SCFA-producing species surprisingly demonstrated inverse correlations with SCFA. Fewer bacterial taxa were associated with acetate to butyrate ratios in IBS compared to health. In participants selected by stool form, we demonstrated differential abundances of microbial genes/pathways for SCFA metabolism and degradation of carbohydrates and mucin across groups. SCFA-producing taxa were reduced in IBS-D patients with BAM.

Conclusion

Keystone taxa responsible for SCFA production differ according to IBS subtype and traits and the IBS microbiome is characterized by reduced functional redundancy. Differences in microbial substrate preferences are also linked to bowel functions. Focusing on taxa that drive SCFA profiles and stool form may be a rational strategy for identifying relevant microbial targets in IBS and other DGBI.

Prevotella copri Improves Selenium Deposition and Meat Quality in the longissimus dorsi Muscle of Fattening Pigs

Selenium is among the important trace elements that influence the quality of meat. Although it has been established that the gut microbiota is closely associated with selenium metabolism, it has yet to be determined whether these microbes influence the accumulation of selenium in muscles. To identify gut microbiota that potentially influence the deposition of selenium in muscles, we compared the colonic microbial composition of pigs characterized by high and low contents of selenium in the longissimus dorsi muscle and accordingly detected a higher abundance of the bacterium Prevotella copri (P. copri) in pigs with a higher muscle selenium content. To verify the effect of P. copri, 16 pigs weighing approximately 61 kg were fed either a basal diet or a basal diet supplemented with P. copri (1.0 × 1010 CFU/kg feed) for 45 days. The results revealed significant increases in the contents of selenium and selenoprotein in the serum and longissimus dorsi muscle of fattening pigs fed the P. copri-supplemented diet. Moreover, supplementing the feed of pigs with P. copri was observed to promote significant improvement in the antioxidant capacity and quality of meat, including drip loss, pH, and meat color. In conclusion, our findings in this study indicate that P. copri has potential utility as a dietary supplement for improving the selenium status and meat quality in fattening pigs.

Gut microbiome and metabolome alterations in traditional Chinese medicine damp-heat constitution following treatment with a Chinese patent medicine and lifestyle intervention

BACKGROUND

The gut microbiota is crucial in human health and diseases. Traditional Chinese Medicine Constitution (TCMC) divides people into those with a balanced constitution (Ping-he [PH]) and those with an unbalanced constitution. Dampness-heat constitution (Shi-re [SR]) is a common unbalanced constitution in the Chinese population and is susceptible to diseases. However, unbalanced constitutions can be regulated by Chinese medicine and lifestyle interventions in clinical practice. Ermiao Pill (EMP) is a Chinese medicine known for clearing heat and draining dampness and improving SR. However, the efficacy and mechanism of EMP are unclear.

HYPOTHESIS/PURPOSE

To determine alterations in the gut microbiota and metabolome in SR and any changes after EMP treatment combined with lifestyle intervention.

STUDY DESIGN

Randomized clinical trial.

METHODS

We enrolled 112 healthy SR individuals and evaluated the efficacy of EMP along with lifestyle interventions. We further assessed serum cytokine levels, serum and urinary metabolomes, and the gut microbiota by 16S rRNA gene sequencing analysis before and after the EMP and lifestyle interventions.

RESULTS

107 SR individuals (55 in the intervention group and 52 in the control group) completed the 1-month-intervention and 1-year-follow-up. The intervention group significantly improved their health status within 1 month, with a reduced SR symptom score, and the efficacy lasted to the 1-year follow-up. The control group needed a further 6 months to reduce the SR symptom score. The gut microbiota of PH individuals was more diverse and had significantly higher proportions of many bacterial species than the SR. Microbiota co-occurrence network analysis showed that SR enriches metabolites correlating with microbial community structure, consistent with traits of healthy SR-enriched microbiota.

CONCLUSION

EMP combined with lifestyle intervention produced health benefits in SR individuals. Our study indicates a pivotal role of gut microbiota and metabolome alterations in distinguishing between healthy SR and PH. Furthermore, the study reveals structural changes of gut microbiota and metabolites induced by EMP and lifestyle intervention. The treatment enriched the number of beneficial bacteria, such as Akkermansia muciniphila and Lactobacillus in the gut. Our findings provide a strong indication that several metabolite factors are associated with the gut microbiota. Moreover, the gut microbiome and metabolome might be powerful tools for TCMC diagnosis and personalized therapy.

The effect of gut microbiome and plasma metabolome on systemic sclerosis: a bidirectional two-sample Mendelian randomization study

Background

Cellular and molecular biology, combined with research on the human microbiome and metabolome, have provided new insights into the pathogenesis of systemic sclerosis (SSc). However, most studies on gut microbiota (GM) and metabolome in SSc are observational studies. The impact of confounding factors and reverse causation leads to different insights. To shed light on this matter, we utilized Mendelian randomization (MR) to determine the causal effect of GM/metabolites on SSc.

Methods

Based on summary-level data from genome-wide association studies, bidirectional Two-sample MR was conducted involving 196 GM, 1400 plasma metabolism, and 9,095 SSc. Inverse Variance Weighting (IVW) was mainly used for effect estimation.

Results

Forward MR analysis found that three GM and two plasma metabolites are causally related to SSc. IVW results showed Victivallaceae (family) (OR, 1.469; 95%CI, 1.099-1.963; p = 0.009) and LachnospiraceaeUCG004 (genus) (OR, 1.548; 95%CI, 1.020-2.349; p = 0.04) were risk factor of SSc. Conversely, Prevotella7 (genus) (OR, 0.759; 95%CI, 0.578-0.997; p = 0.048)was a protective factor of SSc. The results on plasma metabolites indicated that Pregnenediol disulfate (C21H34O8S2) levels (OR, 1.164; 95%CI, 1.006-1.347; p = 0.041)was a risk factor of SSc, while Sphingomyelin (d18:1/19:0, d19:1/18:0) levels (OR, 0.821; 95%CI, 0.677-0.996; p = 0.045)was a protective factor of SSc. Reverse MR analysis did not find causally relationship between SSc and the above GM/plasma metabolites.

Conclusion

Our results revealed the causally effect between GM/plasma metabolites and SSc. These findings provided new insights into the mechanism of SSc. In particular, we demonstrated Prevotella7 was a protective factor of SSc despite its controversial role in SSc in previous researches.

Polystyrene nanoplastics of different particle sizes regulate the polarization of pro-inflammatory macrophages

Microplastics (MPs) are defined as plastic particles smaller than 5 mm in size, and nanoplastics (NPs) are those MPs with a particle size of less than 1000 nm or 100 nm. The prevalence of MPs in the environment and human tissues has raised concerns about their potential negative effects on human health. Macrophages are the major defence against foreign substances in the intestine, and can be polarized into two types: the M1 phenotype and the M2 phenotype. However, the effect of NPs on the polarization of macrophages remains unclear. Herein, we selected polystyrene, one of the most plastics in the environment and controlled the particle sizes at 50 nm and 500 nm respectively to study the effects on the polarization of macrophages. We used mouse RAW264.7 cell line models in this macrophage-associated study. Experiments on cell absorption showed that macrophages could quickly ingest polystyrene nanoplastics of both diameters with time-dependent uptake. Compared to the untreated group and 10 μg/mL treatment group, macrophages exposed to 50 μg/mL groups (50 nm and 500 nm) had considerably higher levels of CD86, iNOS, and TNF-α, but decreased levels of aCD206, IL-10, and Arg-1. According to these findings, macrophage M1 and M2 polarization can both be induced and inhibited by 50 μg/mL 50 nm and 500 nm polystyrene nanoplastics. This work provided the first evidence of a possible MPs mode of action with appropriate concentration and size through the production of polarized M1, providing dietary and environmental recommendations for people, particularly those with autoimmune and autoinflammatory illnesses.

Dynamic Human Gut Microbiome and Immune Shifts During an Immersive Psychosocial Therapeutic Program

Background

Depression is a leading cause of disability worldwide yet its underlying factors, particularly microbial associations, are poorly understood.

Methods

We examined the longitudinal interplay between the microbiome and immune system in the context of depression during an immersive psychosocial intervention. 142 multi-omics samples were collected from 52 well-characterized participants before, during, and three months after a nine-day inquiry-based stress reduction program.

Results

We found that depression was associated with both an increased presence of putatively pathogenic bacteria and reduced microbial beta-diversity. Following the intervention, we observed reductions in neuroinflammatory cytokines and improvements in several mental health indicators. Interestingly, participants with a Prevotella-dominant microbiome showed milder symptoms when depressed, along with a more resilient microbiome and more favorable inflammatory cytokine profile, including reduced levels of CXCL-1.

Conclusions

Our findings reveal a protective link between the Prevotella-dominant microbiome and depression, associated with a less inflammatory environment and moderated symptoms. These insights, coupled with observed improvements in neuroinflammatory markers and mental health from the intervention, highlight potential avenues for microbiome-targeted therapies in depression management.

Unraveling the intricate dance of the Mediterranean diet and gut microbiota in autoimmune resilience

The nutritional habits regulate the gut microbiota and increase risk of an autoimmune disease. Western diet is rich in sugars, meat, and poly-unsaturated fatty acids, which lead to dysbiosis of intestinal microbiota, disruption of gut epithelial barrier and chronic mucosal inflammation. In contrast, the Mediterranean Diet (MedDiet) is abundant in ω3 fatty acids, fruits, and vegetables, possessing anti-inflammatory properties that contribute to the restoration of gut eubiosis. Numerous studies have extensively examined the impact of MedDiet and its components on both health and various disease states. Additionally, specific investigations have explored the correlation between MedDiet, microbiota, and the risk of autoimmune diseases. Furthermore, the MedDiet has been linked to a reduced risk of cardiovascular diseases, playing a pivotal role in lowering mortality rates among individuals with autoimmune diseases and comorbidities. The aim of the present review is to specifically highlight current knowledge regarding possible interactions of MedDiet with the patterns of intestinal microbiota focusing on autoimmunity and a blueprint through dietary modulations for the prevention and management of disease's activity and progression.

Emerging role of gut microbiota in autoimmune diseases

Accumulating studies have indicated that the gut microbiota plays a pivotal role in the onset of autoimmune diseases by engaging in complex interactions with the host. This review aims to provide a comprehensive overview of the existing literatures concerning the relationship between the gut microbiota and autoimmune diseases, shedding light on the complex interplay between the gut microbiota, the host and the immune system. Furthermore, we aim to summarize the impacts and potential mechanisms that underlie the interactions between the gut microbiota and the host in autoimmune diseases, primarily focusing on systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome, type 1 diabetes mellitus, ulcerative colitis and psoriasis. The present review will emphasize the clinical significance and potential applications of interventions based on the gut microbiota as innovative adjunctive therapies for autoimmune diseases.

Host-microbiota interactions in collagen-induced arthritis rats treated with human umbilical cord mesenchymal stem cell exosome and ginsenoside Rh2

Mesenchymal stem cell exosome (MSCs-exo) is a class of products secreted by mesenchymal stem cells (MSCs) that contain various biologically active substances. MSCs-exo is a promising alternative to MSCs due to their lower immunogenicity and lack of ethical constraints. Ginsenoside Rh2 (Rh2) is a hydrolyzed component of the primary active substance of ginsenosides. Rh2 has a variety of pharmacological functions, including anti-inflammatory, anti-tumor, and antioxidant. Studies have demonstrated that gut microbiota and metabolites are critical in developing rheumatoid arthritis (RA). In this study, we constructed a collagen-induced arthritis (CIA) model in rats. We used MSCs-exo combined with Rh2 to treat CIA rats. To observe the effect of MSCs-exo combined with Rh2 on joint inflammation, rat feces were collected for 16 rRNA amplicon sequencing and untargeted metabolomics analysis. The results showed that the arthritis index score and joint swelling of CIA rats treated with MSCs-exo in combination with Rh2 were significantly lower than those of the model and MSCs-exo alone groups. MSCs-exo and Rh2 significantly ameliorated the disturbed gut microbiota in CIA rats. The regulation of Candidatus_Saccharibacteria and Clostridium_XlVb regulation may be the most critical. Rh2 enhanced the therapeutic effect of MSCs-exo compared with the MSCs-exo -alone group. Furthermore, significant changes in gut metabolites were observed in the CIA rat group, and these differentially altered metabolites may act as messengers for host-microbiota interactions. These differential metabolites were enriched into relevant critical metabolic pathways, revealing possible pathways for host-microbiota interactions.

Gold nanoparticles exhibit anti-osteoarthritic effects via modulating interaction of the "microbiota-gut-joint" axis

Osteoarthritis (OA) is a common degenerative joint disease that can cause severe pain, motor dysfunction, and even disability. A growing body of research indicates that gut microbiota and their associated metabolites are key players in maintaining bone health and in the progression of OA. Short-chain fatty acids (SCFAs) are a series of active metabolites that widely participate in bone homeostasis. Gold nanoparticles (GNPs) with outstanding anti-bacterial and anti-inflammatory properties, have been demonstrated to ameliorate excessive bone loss during the progression of osteoporosis (OP) and rheumatoid arthritis (RA). However, the protective effects of GNPs on OA progression are not clear. Here, we observed that GNPs significantly alleviated anterior cruciate ligament transection (ACLT)-induced OA in a gut microbiota-dependent manner. 16S rDNA gene sequencing showed that GNPs changed gut microbial diversity and structure, which manifested as an increase in the abundance of Akkermansia and Lactobacillus. Additionally, GNPs increased levels of SCFAs (such as butyric acid), which could have improved bone destruction by reducing the inflammatory response. Notably, GNPs modulated the dynamic balance of M1/M2 macrophages, and increased the serum levels of anti-inflammatory cytokines such as IL-10. To sum up, our study indicated that GNPs exhibited anti-osteoarthritis effects via modulating the interaction of "microbiota-gut-joint" axis, which might provide promising therapeutic strategies for OA.

Hesperetin regulates the intestinal flora and inhibits the TLR4/NF-κB signaling axis to protect the blood-milk barrier and prevent mastitis

The World Health Organization recommends breastfeeding for 6 months, but mastitis, a common disease during lactation, presents a major obstacle to fulfilling this recommendation. Maternal nutrient intake during lactation has been shown to be related to mastitis. Therefore, this study aimed to explore the effect of hesperetin, a phytonutrient, on mastitis. The oral administration of hesperetin to lipopolysaccharide (LPS)-induced mastitis mice alleviated their pathological damage, reduced the secretion of pro-inflammatory cytokines, and maintained the integrity of their blood-milk barrier. Moreover, our results showed that oral administration of hesperetin regulates the composition of the intestinal flora of mice. Fecal microbial transplantation (FMT) from the mice of hesperetin group alleviated LPS-induced mastitis in recipient mice. In additional, hesperetin attenuated the inflammatory response and increased the expression of tight junction proteins (TJs) in LPS-stimulated mouse mammary epithelial cells (mMECs). Through network pharmacological analysis and further research, we demonstrated hesperetin inhibits the expression of TLR4 and the activation of NF-κB signaling. In conclusion, hesperetin protects the blood-milk barrier and improve mastitis by regulating intestinal flora and inhibiting the activation of TLR4/NF-κB signaling axis. This study provides a theoretical basis for lactating females to consume hesperetin as a supplement to prevent mastitis and maintain mammary health.

Microbial Mechanisms of Rheumatoid Arthritis Pathogenesis

PURPOSE OF REVIEW

Host-microbiome interactions have been implicated in the pathophysiology of rheumatoid arthritis (RA), but the data linking specific microbes to RA is largely associative. Here, we review recent studies that have interrogated specific mechanistic links between microbes and host in the setting of RA.

RECENT FINDINGS

Several candidate bacterial species and antigens that may trigger the conversion of an anti-bacterial to an autoimmune response have been recently identified. Additional studies have identified microbial metabolic pathways that are altered in RA. Some of these microbial species and metabolic pathways have been validated in mouse models to induce RA-like immune responses, providing initial evidence of specific mechanisms by which the microbiota contributes to the development of RA. Several microbial species, antigens, and metabolites have been identified as potential contributors to RA pathophysiology. Further interrogation and validation of these pathways may identify novel biomarkers of or therapeutic avenues for RA.

Effects of dietary intervention on human diseases: molecular mechanisms and therapeutic potential

Diet, serving as a vital source of nutrients, exerts a profound influence on human health and disease progression. Recently, dietary interventions have emerged as promising adjunctive treatment strategies not only for cancer but also for neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions have demonstrated substantial potential in modulating metabolism, disease trajectory, and therapeutic responses. Metabolic reprogramming is a hallmark of malignant progression, and a deeper understanding of this phenomenon in tumors and its effects on immune regulation is a significant challenge that impedes cancer eradication. Dietary intake, as a key environmental factor, can influence tumor metabolism. Emerging evidence indicates that dietary interventions might affect the nutrient availability in tumors, thereby increasing the efficacy of cancer treatments. However, the intricate interplay between dietary interventions and the pathogenesis of cancer and other diseases is complex. Despite encouraging results, the mechanisms underlying diet-based therapeutic strategies remain largely unexplored, often resulting in underutilization in disease management. In this review, we aim to illuminate the potential effects of various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet, on cancer and the aforementioned diseases. We explore the multifaceted impacts of these dietary interventions, encompassing their immunomodulatory effects, other biological impacts, and underlying molecular mechanisms. This review offers valuable insights into the potential application of these dietary interventions as adjunctive therapies in disease management.

Metabolite-sensing GPCRs in rheumatoid arthritis

Persistent inflammation in damaged joints results in metabolic dysregulation of the synovial microenvironment, causing pathogenic alteration of cell activity in rheumatoid arthritis (RA). Recently, the role of metabolite and metabolite-sensing G protein-coupled receptors (GPCRs) in the RA-related inflammatory immune response (IIR) has become a focus of research attention. These GPCRs participate in the progression of RA by modulating immune cell activation, migration, and inflammatory responses. Here, we discuss recent evidence implicating metabolic dysregulation in RA pathogenesis, focusing on the connection between RA-related IIR and GPCR signals originating from the synovial joint and gut. Furthermore, we discuss future directions for targeting metabolite-sensing GPCRs for therapeutic benefit, emphasizing the importance of identifying endogenous ligands and investigating the various transduction mechanisms involved.

Regulation of polysaccharide in Wu-tou decoction on intestinal microflora and pharmacokinetics of small molecular compounds in AIA rats

Wu-tou decoction (WTD), a traditional Chinese medicine prescription, is used to treat rheumatoid arthritis (RA). It works by controlling intestinal flora and its metabolites, which in turn modulates the inflammatory response and intestinal barrier function. Small molecular compounds (SM) and polysaccharides (PS) were the primary constituents of WTD extract. In this work, a model of adjuvant-induced arthritis (AIA) in rats was established and treated with WTD, SM, and PS, respectively. 16S rRNA gene sequencing was used to examine the regulatory impact of the various groups on the disturbance of the gut flora induced by RA. Further, since PS cannot be absorbed into the blood, the influence of PS on the absorption and metabolism of SM was studied by examining their pharmacokinetic (PK) parameters of 23 active components in SM by UPLC-MS/MS. WTD was found to be more effective than PS and SM in alleviating arthritis in AIA rats, which may be related to changes in gut flora. The PK properties of 13 active compounds were altered after PS intervene. Based on the findings, PS may be able to manage the disruption of intestinal microbiota, enhance the intestinal environment of model animals, and hence influence SM absorption and metabolism.

Prevotella copri exhausts intrinsic indole-3-pyruvic acid in the host to promote breast cancer progression: inactivation of AMPK via UHRF1-mediated negative regulation

Emerging evidence has revealed the novel role of gut microbiota in the development of cancer. The characteristics of function and composition in the gut microbiota of patients with breast cancer patients has been reported, however the detailed causation between gut microbiota and breast cancer remains uncertain. In the present study, 16S rRNA sequencing revealed that Prevotella, particularly the dominant species Prevotella copri, is significantly enriched and prevalent in gut microbiota of breast cancer patients. Prior-oral administration of P. copri could promote breast cancer growth in specific pathogen-free mice and germ-free mice, accompanied with sharp reduction of indole-3-pyruvic acid (IPyA). Mechanistically, the present of excessive P. copri consumed a large amount of tryptophan (Trp), thus hampering the physiological accumulation of IPyA in the host. Our results revealed that IPyA is an intrinsic anti-cancer reagent in the host at physiological level. Briefly, IPyA directly suppressed the transcription of UHRF1, following by the declined UHRF1 and PP2A C in nucleus, thus inhibiting the phosphorylation of AMPK, which is just opposite to the cancer promoting effect of P. copri. Therefore, the exhaustion of IPyA by excessive P. copri strengthens the UHRF1-mediated negative control to inactivated the energy-controlling AMPK signaling pathway to promote tumor growth, which was indicated by the alternation in pattern of protein expression and DNA methylation. Our findings, for the first time, highlighted P. copri as a risk factor for the progression of breast cancer.

Probiotic-Fermented Distillers Grain Alters the Rumen Microbiome, Metabolome, and Enzyme Activity, Enhancing the Immune Status of Finishing Cattle

A total of 30 Simmental crossbred cattle (6.50 months old, 265.0 ± 22.48 kg) were randomly divided into three groups, with 10 heads per group, and fed for 45 days. The diet treatments consisted of the Control group without PFDG supplementation, the PFDG-15% group with 15% PFDG substituting for 15% concentrate, and PFDG-30% group with 30% PFDG substituting for 30% concentrate. The results showed that compared with the Control group, the average daily gain (ADG) of the cattle in the PFDG-30% group decreased significantly (0.890 vs. 0.768 kg/d, p = 0.005). The serum malondialdehyde content of cattle in the PFDG-15% and PFDG-30% groups decreased significantly (p = 0.047) compared to that of the Control group. However, the serum superoxide dismutase activity of cattle in the PFDG-30% group was significantly higher than that of the Control group (p = 0.047). Meanwhile, both the PFDG-15% and PFDG-30% groups (1758.47 vs. 2061.30 μg/mL) showed higher serum levels of immunoglobulin G, while the interleukin-10 concentration was lower in the PFDG-30% group (p = 0.027). In addition, the PFDG-15% and PFDG-30% groups shifted the rumen microbiota by improving the abundances of F082 (related to propionic acid production) and fiber-degrading bacteria (Lachnospiraceae_UGG-009 and Prevotellaceae_UCG-001) and reducing the abundance of the disease-associated bacteria Selenomonas. A Kyoto encyclopedia of genes and genomes (KEGG) analysis illustrated that three key metabolic pathways, including phenylalanine metabolism, pyrimidine metabolism, and tryptophan metabolism, were enriched in the PFDG-15% group, but eight key metabolic pathways, including arachidonic acid metabolism, were enriched in the PFDG-30% group. Importantly, both the PFDG-15% and PFDG-30% groups increased (p < 0.01) the activities of cellulase, lipase, and protease in the rumen. Finally, the different bacterial abundance in the rumen was associated with changes in the ADG, serum antioxidant capacity, immune status, rumen enzyme activity, and metabolites. These results suggest that PFDG alters rumen microbiome abundance, metabolome, and enzyme activity for enhancing serum antioxidant capacity and the immune status, but when the supplemental level reaches 30%, it has a negative effect on ADG and the anti-inflammatory factors in finishing cattle.

Current insights on the roles of gut microbiota in inflammatory bowel disease-associated extra-intestinal manifestations: pathophysiology and therapeutic targets

Inflammatory bowel disease (IBD) is a chronic, recurrent inflammatory disease of the gastrointestinal tract. In addition to digestive symptoms, patients with IBD may also develop extra-intestinal manifestations (EIMs), the etiology of which remains undefined. The gut microbiota has been reported to exert a critical role in the pathogenesis of IBD, with a similar pattern of gut dysbiosis observed between patients with IBD and those with EIMs. Therefore, it is hypothesized that the gut microbiota is also involved in the pathogenesis of EIMs. The potential mechanisms are presented in this review, including: 1) impaired gut barrier: dysbiosis induces pore formation in the intestinal epithelium, and activates pattern recognition receptors to promote local inflammation; 2) microbial translocation: intestinal pathogens, antigens, and toxins translocate via the impaired gut barrier into extra-intestinal sites; 3) molecular mimicry: certain microbial antigens share similar epitopes with self-antigens, inducing inflammatory responses targeting extra-intestinal tissues; 4) microbiota-related metabolites: dysbiosis results in the dysregulation of microbiota-related metabolites, which could modulate the differentiation of lymphocytes and cytokine production; 5) immunocytes and cytokines: immunocytes are over-activated and pro-inflammatory cytokines are excessively released. Additionally, we summarize microbiota-related therapies, including probiotics, prebiotics, postbiotics, antibiotics, and fecal microbiota transplantation, to promote better clinical management of IBD-associated EIMs.

Gut microbiota, immunity, and bile acid metabolism: decoding metabolic disease interactions

In recent decades, the global prevalence of metabolic syndrome has surged, posing a significant public health challenge. Metabolic disorders, encompassing diabetes, obesity, nonalcoholic fatty liver disease, and polycystic ovarian syndrome, have been linked to alterations in the gut microbiota. Nonetheless, the connection between gut microbiota and host metabolic diseases warrants further investigation. In this review, we delve into the associations between various metabolic disorders and the gut microbiota, focusing on immune responses and bile acid (BA) metabolism. Notably, T helper cells, innate lymphoid cells, macrophages, and dendritic cells have been shown to modulate host metabolism through interactions with intestinal microorganisms and the release of cytokines. Furthermore, secondary BA metabolites, derived from the microbiota, are involved in the pathogenesis of metabolic diseases via the farnesoid X receptor and Takeda G protein-coupled receptor 5. By covering both aspects of this immune system-microorganism axis, we present a comprehensive overview of the roles played by the gut microbiota, microbiota-derived BA metabolites, and immune responses in metabolic diseases, as well as the interplay between these systems.

Enhanced trimethylamine metabolism and gut dysbiosis in type 2 diabetes mellitus with microalbumin

Background

Abnormal gut microbiota and blood trimethylamine-N-oxide (TMAO) metabolome have been reported in patients with type 2 diabetes mellitus (T2DM) and advanced diabetic nephropathy. This study aimed to investigate the gut microbiota profiles and a group of targeted urine metabolic characteristics in T2DM patients with or without microalbuminuria, to determine the correlation between the gut microbiota composition, trimethylamine (TMA) metabolism, and the clinical features during progression of diabetic kidney disease (DKD).

Methods

This study included 26 T2DM patients with microalbuminuria (Micro), 26 T2DM patients with normoalbuminuria (Normo), and 15 healthy controls (HC). Urine and Fecal samples were detected using ultra performance liquid chromatography tandem mass spectrometry and 16S ribosomal DNA gene sequencing, respectively.

Results

The TMAO/TMA ratio decreased gradually during the HC-Normo-Micro transition. The levels of TMA, choline and betaine were significantly different between the HC group and the T2DM patients belonging to both Normo and Micro groups. At the operational taxonomic unit (OTU) level, the gut microflora diversity was significantly reduced in the Micro groups compared to the HC groups and the Normo groups. Taxonomic analyses revealed significant consumption in the relative abundances of eight bacterial genera and significant enrichment of two bacterial genera during the HC-Normo-Micro transition. Furthermore, the relative abundances of six bacterial genera, namely, Ruminococcus_1, [Eubacterium]_ruminantium_group, Roseburia, Faecalibacterium, Fusicatenibacter and Coprococcus_3 exhibited significant differences, and were associated with elevated urinary albumin creatinine ratio (UACR), TMAO/TMA, TMA and its precursors in the Micro group compared with the other groups.

Conclusion

The imbalance of gut microbiota has occurred in patients with early-stage DKD, and the consumption of short-chain fatty acid-producing bacteria were associated with the accumulation of TMA and UACR.

Postbiotics in rheumatoid arthritis: emerging mechanisms and intervention perspectives

Rheumatoid arthritis (RA) is a prevalent chronic autoimmune disease that affects individuals of all age groups. Recently, the association between RA and the gut microbiome has led to the investigation of postbiotics as potential therapeutic strategies. Postbiotics refer to inactivated microbial cells, cellular components, or their metabolites that are specifically intended for the microbiota. Postbiotics not only profoundly influence the occurrence and development of RA, but they also mediate various inflammatory pathways, immune processes, and bone metabolism. Although they offer a variety of mechanisms and may even be superior to more conventional "biotics" such as probiotics and prebiotics, research on their efficacy and clinical significance in RA with disruptions to the intestinal microbiota remains limited. In this review, we provide an overview of the concept of postbiotics and summarize the current knowledge regarding postbiotics and their potential use in RA therapy. Postbiotics show potential as a viable adjunctive therapy option for RA.

Mitochondrion-NLRP3 inflammasome activation in macrophages: A novel mechanism of the anti-inflammatory effect of Notopterygium in rheumatoid arthritis treatment

OBJECTIVE

The mechanism by which Notopterygium (NE) regulates the nucleotide-binding, oligomerization domain (NOD)-like receptor family and pyrin domain-containing 3 (NLRP3) inflammasome to treat rheumatoid arthritis (RA) was investigated to reveal the scientific implications of NE in RA treatment.

METHODS

Adjuvant arthritis (AA) rats were replicated. After NE intervention, the anti-inflammatory efficacy of NE in vivo was determined. The mechanism of NE in RA treatment was predicted by network pharmacology, and the key target for further experiments was found through the analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG). The effect of NE on the NLRP3 inflammasome in AA rats was verified. Furthermore, with the induction of inflammation in RAW264.7 cells by lipopolysaccharide (LPS), several techniques, such as Griess assay, enzyme linked immunosorbent assays, electron microscopy, and fluorescence probe technology, were used to investigate the anti-inflammatory and related mechanisms of NE in RA treatment.

RESULTS

NE could inhibit inflammation in AA rats. KEGG results showed that NLRP3 participated in the top three pathways of NE in RA treatment. Through Western blotting and immunofluorescence assays, this study demonstrated that NE can regulate NLRP3, pro-Caspase-1, Caspase-1, and CD11b in the ankle joint of AA rats. NE may significantly reduce the LPS-induced inflammatory response of RAW264.7 cells by alleviating mitochondrial damage, reducing the number of mitochondrial deoxyribonucleic Acid and mitochondrial reactive oxygen species, inhibiting NLRP3 inflammasome activation.

CONCLUSION

The anti-inflammatory and antirheumatic effect of NE may involve regulating NLRP3 inflammasome activation through mitochondria. NLRP3 is probably the key target molecule of NE in the treatment of RA.

Processing and storage methods affect oral and gut microbiome composition

In microbiome studies, fecal and oral samples are stored and processed in different ways, which could affect the observed microbiome composition. In this study, we compared storage and processing methods applied to samples prior to DNA extraction to determine how each affected microbial community diversity as assessed by 16S rRNA gene sequencing. We collected dental swabs, saliva, and fecal samples from 10 individuals, with three technical replicates per condition. We assessed four methods of storing and processing fecal samples prior to DNA extraction. We also compared different fractions of thawed saliva and dental samples to fresh samples. We found that lyophilized fecal samples, fresh whole saliva samples, and the supernatant fraction of thawed dental samples had the highest levels of alpha diversity. The supernatant fraction of thawed saliva samples had the second highest evenness compared to fresh saliva samples. Then, we investigated the differences in observed community composition at the domain and phylum levels and identified the amplicon sequence variants (ASVs) that significantly differed in relative abundance between the conditions. Lyophilized fecal samples had a greater prevalence of Archaea as well as a greater ratio of Firmicutes to Bacteroidetes compared to the other conditions. Our results provide practical considerations not only for the selection of storage and processing methods but also for comparing results across studies. Differences in processing and storage methods could be a confounding factor influencing the presence, absence, or differential abundance of microbes reported in conflicting studies.

Efficacy and safety of tripterygium wilfordii Hook F plus TNF inhibitor for active rheumatoid arthritis: A multicentre, randomized, double-blind, triple-dummy controlled trial

An investigator-initiated, multicentre, randomized, double-blind, triple-dummy, controlled trial was conducted at 14 tertiary rheumatology centers in China to evaluate the efficacy and safety of Tripterygium wilfordii Hook F (TwHF) with recombinant human TNF receptor IgGFc fusion protein (rhTNFR-Fc) in active Rheumatoid Arthritis (RA). Primary endpoint was the proportion of patients achieved a 50% improvement of American College of Rheumatology criteria (ACR50) in TwHF+rhTNFR-Fc vs. methotrexate (MTX) group at week 12. ACR50 was achieved in 57.1% (72/126), 41.3% (52/126), 23.0% (29/126), and 26.2% (33/126) patients receiving TwHF+rhTNFR-Fc, MTX + rhTNFR-Fc, TwHF and MTX monotherapy, respectively, at week 12 (TwHF+rhTNFR-Fc vs. other three groups, all p < 0.05). No statistical difference in serious adverse events or adverse events leading to discontinuation of study across all groups was documented. TwHF+rhTNFR-Fc was superior to MTX for active RA, and was more effective than MTX + rhTNFR-Fc on ACR50, with a similar safety profile. Trial registration:ClinicalTrials.govNCT03589833.

Modifiable risk factors linked to the development of rheumatoid arthritis: evidence, immunological mechanisms and prevention

Rheumatoid Arthritis (RA) is a common autoimmune disease that targets the synovial joints leading to arthritis. Although the etiology of RA remains largely unknown, it is clear that numerous modifiable risk factors confer increased risk to developing RA. Of these risk factors, cigarette smoking, nutrition, obesity, occupational exposures and periodontal disease all incrementally increase RA risk. However, the precise immunological mechanisms by which these risk factors lead to RA are not well understood. Basic and translational studies have provided key insights into the relationship between inflammation, antibody production and the influence in other key cellular events such as T cell polarization in RA risk. Improving our general understanding of the mechanisms which lead to RA will help identify targets for prevention trials, which are underway in at-risk populations. Herein, we review the modifiable risk factors that are linked to RA development and describe immune mechanisms that may be involved. We highlight the few studies that have sought to understand if modification of these risk factors reduces RA risk. Finally, we speculate that modification of risk factors may be an appealing avenue for prevention for some at-risk individuals, specifically those who prefer lifestyle interventions due to safety and economic reasons.

Processing and Storage Methods Affect Oral and Gut Microbiome Composition

Across microbiome studies, fecal and oral samples are stored and processed in different ways, which could affect the observed microbiome composition. Here, we compared treatment methods, which included both storage conditions and processing methods, applied to samples prior to DNA extraction to determine how each affects microbial community diversity as assessed by 16S rRNA gene sequencing. We collected dental swab, saliva, and fecal samples from 10 individuals, with three technical replicates per treatment method. We assessed four methods of processing fecal samples prior to DNA extraction. We also compared different fractions of frozen saliva and dental samples to fresh samples. We found that lyophilized fecal samples, fresh whole saliva samples, and the supernatant fraction of thawed dental samples retained the highest levels of alpha diversity in samples. The supernatant fraction of thawed saliva samples had the second highest alpha diversity compared to fresh. Then we investigated the differences in microbes between different treatments at the domain and phylum levels as well as identified the amplicon sequence variants (ASVs) that were significantly different between the methods producing the highest alpha diversity and the other treatment methods. Lyophilized fecal samples had a greater prevalence of Archaea as well as a greater ratio of Firmicutes to Bacteroidetes compared to the other treatment methods. Our results provide practical considerations, not only for selection of processing method, but also for comparing results across studies that use these methods. Our findings also indicate differences in treatment method could be a confounding factor influencing the presence, absence, or differential abundance of microbes reported in conflicting studies.

Structural characterization of a fucoidan from Ascophyllum nodosum and comparison of its protective effect against cellular oxidative stress with its analogues

In the present study, a fucoidan fraction (ANP-3) was isolated from Ascophyllum nodosum, and the combined application of desulfation, methylation, HPGPC, HPLC-MSn, FT-IR, GC-MS, NMR, and Congo red test elucidated ANP-3 (124.5 kDa) as a triple-helical sulfated polysaccharide constituted by →2)-α-Fucp3S-(1→, →3)-α-Fucp2S4S-(1→, →3,6)-β-Galp4S-(1→, →3,6)-β-Manp4S-(1→, →3,6)-β-Galp4S-(1→，→6)-β-Manp-(1→, →3)-β-Galp-(1→, α-Fucp-(1→, and α-GlcAp-(1→ residues. To better understand the relationship between the fucoidan structure of A. nodosum and protective effects against oxidative stress, two fractions ANP-6 and ANP-7 were used as contrast. ANP-6 (63.2 kDa) exhibited no protective effect against H2O2-induced oxidative stress. However, ANP-3 and ANP-7 with the same molecular weight of 124.5 kDa could protect against oxidative stress by down-regulating reactive oxygen species (ROS) and malondialdehyde (MDA) levels and up-regulating total antioxidant capability (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities. Then metabolites analysis indicated that arginine biosynthesis and phenylalanine, tyrosine, and tryptophan biosynthesis metabolic pathways and metabolic biomarkers such as betaine were involved in the effects of ANP-3 and ANP-7. The better protective effect of ANP-7 compared to that of ANP-3 could be attributed to its relatively higher molecular weight, sulfate substitution and →6)-β-Galp-(1→ content, and lower uronic acid content.

Fusobacterium nucleatum aggravates rheumatoid arthritis through FadA-containing outer membrane vesicles

Rheumatoid arthritis (RA) is an autoimmune disorder that has been associated with the gut microbiota. However, whether and how the gut microbiota plays a pathogenic role in RA remains unexplored. Here, we observed that Fusobacterium nucleatum is enriched in RA patients and positively associated with RA severity. F. nucleatum similarly aggravates arthritis in a mouse model of collagen-induced arthritis (CIA). F. nucleatum outer membrane vesicles (OMVs) containing the virulence determinant FadA translocate into the joints, triggering local inflammatory responses. Specifically, FadA acts on synovial macrophages, resulting in the activation of the Rab5a GTPase involved in vesicle trafficking and inflammatory pathways and YB-1, a key regulator of inflammatory mediators. OMVs containing FadA and heightened Rab5a-YB-1 expression were observed in RA patients compared with controls. These findings suggest a causal role of F. nucleatum in aggravating RA and provide promising therapeutic targets for clinically ameliorating RA.