Effects of Taurine on Gut Microbiota Homeostasis: An Evaluation Based on Two Models of Gut Dysbiosis

Artesunate ameliorates diabetic xerostomia in rats through regulating oral microbiota and metabolic profile in salivary gland based on NF-κB/NLRP3 signaling pathway

BACKGROUND

Artemisia annua. L, as a valuable Chinese medicine, has been applied for millennia in China. Its major active ingredient, artemisinin, has demonstrated diverse pharmacological properties, including anti-inflammatory, antioxidant, and anti-diabetic effects. Recent studies suggest that artesunate (ART), an artemisinin derivative, exhibits promising therapeutic effects on diabetic complications. Nevertheless, the role and underlying mechanisms of ART in the treatment of diabetic xerostomia (DX) remain unclear.

AIM

This study aimed to elucidate the effects of ART on DX in a type 2 diabetes mellitus (T2DM) rat model, primarily from the perspective of oral microbiota and salivary gland (SG) metabolism, and to further explore potential mechanisms involved.

METHODS

Various assessments including blood levels, insulin resistance (IR), saliva flow rate, as well as histological analyses through hematoxylin and eosin and Masson staining were performed to verify the reliability of DX model and protective effects of ART on the DX. Untargeted metabolomics and 16S rDNA sequencing were employed to respectively evaluate effects of ART on metabolite changes in SG and oral microbiota in the DX rats. Network pharmacology was employed to predict key pathways and targets with critical roles in ART's therapeutic effect on DX. Additionally, molecular docking and molecular dynamics (MD) simulations were utilized to evaluate interactions between ART and the identified key pathway targets. Surface plasmon resonance (SPR) experiment was performed to verify our computational predictions. Finally, molecular biology experiments were conducted to further validate the identified key pathway targets.

RESULTS

ART treatment ameliorated the hyperglycemia, IR and hyposalivation, and ameliorated pathological changes and oxidative stress of SGs in the DX rats. Besides, 16S rDNA sequencing suggested that ART alleviated the perturbation of oral microbiota (such as Veillonella, Lactobacillus, Clostridium sensu stricto 1, Escherichia-Shigella, and Dubosiella). Untargeted metabolomics revealed that steroid hormone biosynthesis, taurine and hypotaurine metabolism of SGs in the DX rats were partially corrected by ART treatment. Correlation analysis demonstrated an obvious association between the oral microbiota species and SG metabolites. Network pharmacology analysis identified NF-κB pathway as a critical pathway of ART in treating DX. Meanwhile, molecular docking and MD simulation suggested stable binding of ART to NF-κB/NLRP3 pathway targets, particularly NLRP3. Furthermore, SPR confirmed a stable binding of ART to NLRP3, a key target in the NF-κB/NLRP3 pathway. Oxidative stress indicators involved in NF-κB pathway, including MDA and SOD levels, were significantly reduced after ART intervention. Western blotting and qRT-PCR experiments further revealed that ART inhibited increase of NF-κB/NLRP3 pathway related targets expression, including NF-κB, NLRP3, Caspase1, IL-1β, IL-18, TNF-α, and IL-6 in the SGs of DX rats.

CONCLUSION

ART exerted beneficial therapeutic effects on DX by modulating oral microbiota dysbiosis and restoring SG's metabolic profiles, and inhibiting activation of NF-κB/NLRP3 pathway, suggesting its potential novel application in DX treatment.

Interplay between gut microbial communities and metabolites modulates pan-cancer immunotherapy responses

Immune checkpoint blockade (ICB) therapy has revolutionized cancer treatment but remains effective in only a subset of patients. Emerging evidence suggests that the gut microbiome and its metabolites critically influence ICB efficacy. In this study, we performed a multi-omics analysis of fecal microbiomes and metabolomes from 165 patients undergoing anti-programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) therapy, identifying microbial and metabolic entities associated with treatment response. Integration of data from four public metagenomic datasets (n = 568) uncovered cross-cohort microbial and metabolic signatures, validated in an independent cohort (n = 138). An integrated predictive model incorporating these features demonstrated robust performance. Notably, we characterized five response-associated enterotypes, each linked to specific bacterial taxa and metabolites. Among these, the metabolite phenylacetylglutamine (PAGln) was negatively correlated with response and shown to attenuate anti-PD-1 efficacy in vivo. This study sheds light on the interplay among the gut microbiome, the gut metabolome, and immunotherapy response, identifying potential biomarkers to improve treatment outcomes.

Dietary Taurine Regulation of the Intestinal Microbiome in Chinese Stripe-Necked Turtle (Mauremys sinensis)

Taurine is essential for sustaining the body's physiological equilibrium and is extensively utilized as a dietary supplement and immune system enhancer for aquatic creatures. The gut microbiota serves as a vital health indicator in animals. In this study, our goal was to evaluate the effects of dietary taurine on the gut microbiome of Chinese stripe-necked turtles (Mauremys sinensis). Turtles were evenly divided into three supplementation groups: a control group with no taurine in the diet, a low group with 0.1% taurine, and a high group with 0.4% taurine. High-throughput sequencing was employed to analyze the gut microbiome's composition and structure. The results showed that the impact of taurine supplementation on the α-diversity and β-diversity of the gut microbiome was not statistically significant. At the phylum level, Firmicutes and Bacteroidetes predominated the gut microbiome. At the genus level, three beneficial bacteria, Clostridium_sensu_stricto_13, Pygmaiobacter, and Terrisporobacter showed significant differences under different levels of taurine supplementation and increased in abundance with the supplementation of taurine, while the harmful bacterium Brucella decreased in abundance with the addition of taurine and exhibited significant differences. Furthermore, LEfSe analysis and functional predictions highlighted significant variations in the functional traits of gram-positive intestinal bacteria among the different taurine supplementation levels. These findings imply that dietary taurine may alter the intestinal microbiome structure in Chinese stripe-necked turtles, offering valuable insights for the scientific assessment of taurine's health benefits as a feed additive and potentially guiding the formulation of more informed and healthier feeding practices.

The Impact of Green Tea Kombucha on the Intestinal Health, Gut Microbiota, and Serum Metabolome of Individuals with Excess Body Weight in a Weight Loss Intervention: A Randomized Controlled Trial

Green tea kombucha (GTK) has emerged as a promising probiotic fermented beverage. Few studies have investigated its effect on human health, mainly focusing on intestinal health, microbiota composition, and metabolomics. The present study is a pioneer in investigating the effect of GTK consumption in individuals with excess body weight. This is a randomized controlled trial, lasting ten weeks, with two groups placed under an energy-restricted diet: control (CG, n = 29), kombucha (KG, n = 30; 200 mL/d). Biological samples and questionnaires were collected before and after the intervention. Microbiota analysis used an amplification of the V4 region of 16S rRNA. Serum untargeted metabolomics used HPLC-TOF mass spectrometry. Intestinal permeability considered the urine excretion of lactulose and mannitol, plasma zonulin, and LPS-binding protein. After the intervention, no differences related to intestinal permeability and microbiota were found between groups, but only the CG had increased fecal pH, lactulose/mannitol ratio, and zonulin. In addition to this, the KG reported lower gastrointestinal symptoms related to motility compared to the CG, and discriminant metabolites (e.g., diethyl malonate) were found strictly in the KG. GTK did not significantly improve gut microbiota and intestinal permeability. However, GTK ameliorated gastrointestinal symptoms and positively influenced the serum metabolome, which may contribute to enhancing the metabolic health of individuals with excess body weight.

Feeding gut microbes to nourish the brain: unravelling the diet-microbiota-gut-brain axis

The prevalence of brain disorders, including stress-related neuropsychiatric disorders and conditions with cognitive dysfunction, is rising. Poor dietary habits contribute substantially to this accelerating trend. Conversely, healthy dietary intake supports mood and cognitive performance. Recently, the communication between the microorganisms within the gastrointestinal tract and the brain along the gut-brain axis has gained prominence as a potential tractable target to modulate brain health. The composition and function of the gut microbiota is robustly influenced by dietary factors to alter gut-brain signalling. To reflect this interconnection between diet, gut microbiota and brain functioning, we propose that a diet-microbiota-gut-brain axis exists that underpins health and well-being. In this Review, we provide a comprehensive overview of the interplay between diet and gut microbiota composition and function and the implications for cognition and emotional functioning. Important diet-induced effects on the gut microbiota for the development, prevention and maintenance of neuropsychiatric disorders are described. The diet-microbiota-gut-brain axis represents an uncharted frontier for brain health diagnostics and therapeutics across the lifespan.

Environmentally Relevant Levels of Antiepileptic Carbamazepine Altered Intestinal Microbial Composition and Metabolites in Amphibian Larvae

There is growing concern about the potential ecological risks posed by pharmaceutical residues in the aquatic environment. However, our understanding of the toxic effects of antiepileptic pharmaceuticals, such as carbamazepine (CBZ), on aquatic animal larvae is still limited. In this study, the tadpoles of the black-spotted pond frog (Pelophylax nigromaculatus) were exposed to environmentally relevant concentrations of CBZ (0.3 and 3.0 μg/L) for 30 days, and their growth, intestinal microbial composition, and metabolites were investigated to assess the potential toxic effects of CBZ in non-targeted aquatic organisms. Some tadpoles died during exposure, but there was no significant among-group difference in the survival and growth rates. CBZ exposure significantly altered the composition of tadpole intestinal microbiota. Relative abundances of some bacterial genera (e.g., Blautia, Prevotella, Bacillus, Microbacterium, etc.) decreased, while others (e.g., Paucibacter, etc.) increased in CBZ-exposed tadpoles. Interestingly, CBZ-induced alterations in some bacteria might not necessarily lead to adverse outcomes for animals. Meanwhile, small molecular intestinal metabolites related to energy metabolism, and antioxidant and anti-inflammatory activities were also altered after exposure. Taken together, environmentally relevant levels of CBZ might alter the metabolic and immune performances of amphibian larvae by modifying the abundance of some specific bacteria and the level of metabolites in their intestines, thereby potentially causing a long-term effect on their fitness.

Plasma taurine level is linked to symptom burden and clinical outcomes in post-COVID condition

BACKGROUND

A subset of individuals (10-20%) experience post-COVID condition (PCC) subsequent to initial SARS-CoV-2 infection, which lacks effective treatment. PCC carries a substantial global burden associated with negative economic and health impacts. This study aims to evaluate the association between plasma taurine levels with self-reported symptoms and adverse clinical outcomes in patients with PCC.

METHODS AND FINDINGS

We analyzed the plasma proteome and metabolome of 117 individuals during their acute COVID-19 hospitalization and at the convalescence phase six-month post infection. Findings were compared with 28 age and sex-matched healthy controls. Plasma taurine levels were negatively associated with PCC symptoms and correlated with markers of inflammation, tryptophan metabolism, and gut dysbiosis. Stratifying patients based on the trajectories of plasma taurine levels during six-month follow-up revealed a significant association with adverse clinical events. Increase in taurine levels during the transition to convalescence were associated with a reduction in adverse events independent of comorbidities and acute COVID-19 severity. In a multivariate analysis, increased plasma taurine level between acute and convalescence phase was associated with marked protection from adverse clinical events with a hazard ratio of 0.13 (95% CI: 0.05-0.35; p<0.001).

CONCLUSIONS

Taurine emerges as a promising predictive biomarker and potential therapeutic target in PCC. Taurine supplementation has already demonstrated clinical benefits in various diseases and warrants exploration in large-scale clinical trials for alleviating PCC.

Influence of Bariatric Surgery on Gut Microbiota Composition and Its Implication on Brain and Peripheral Targets

Obesity remains a significant global health challenge, with bariatric surgery remaining as one of the most effective treatments for severe obesity and its related comorbidities. This review highlights the multifaceted impact of bariatric surgery beyond mere physical restriction or nutrient malabsorption, underscoring the importance of the gut microbiome and neurohormonal signals in mediating the profound effects on weight loss and behavior modification. The various bariatric surgery procedures, such as Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), act through distinct mechanisms to alter the gut microbiome, subsequently impacting metabolic health, energy balance, and food reward behaviors. Emerging evidence has shown that bariatric surgery induces profound changes in the composition of the gut microbiome, notably altering the Firmicutes/Bacteroidetes ratio and enhancing populations of beneficial bacteria such as Akkermansia. These microbiota shifts have far-reaching effects beyond gut health, influencing dopamine-mediated reward pathways in the brain and modulating the secretion and action of key gut hormones including ghrelin, leptin, GLP-1, PYY, and CCK. The resultant changes in dopamine signaling and hormone levels contribute to reduced hedonic eating, enhanced satiety, and improved metabolic outcomes. Further, post-bariatric surgical effects on satiation targets are in part mediated by metabolic byproducts of gut microbiota like short-chain fatty acids (SCFAs) and bile acids, which play a pivotal role in modulating metabolism and energy expenditure and reducing obesity-associated inflammation, as well as influencing food reward pathways, potentially contributing to the regulation of body weight and reduction in hedonic eating behaviors. Overall, a better understanding of these mechanisms opens the door to developing non-surgical interventions that replicate the beneficial effects of bariatric surgery on the gut microbiome, dopamine signaling, and gut hormone regulation, offering new avenues for obesity treatment.

Protective Role of Taurine on Rat Offspring Hypertension in the Setting of Maternal Chronic Kidney Disease

Taurine is a natural antioxidant with antihypertensive properties. Maternal chronic kidney disease (CKD) has an impact on renal programming and increases the risk of offspring hypertension in later life. The underlying mechanisms cover oxidative stress, a dysregulated hydrogen sulfide (H2S) system, dysbiotic gut microbiota, and inappropriate activation of the renin-angiotensin-aldosterone system (RAAS). We investigated whether perinatal taurine administration enables us to prevent high blood pressure (BP) in offspring complicated by maternal CKD. Before mating, CKD was induced through feeding chow containing 0.5% adenine for 3 weeks. Taurine was administered (3% in drinking water) during gestation and lactation. Four groups of male offspring were used (n = 8/group): controls, CKD, taurine-treated control rats, and taurine-treated rats with CKD. Taurine treatment significantly reduced BP in male offspring born to mothers with CKD. The beneficial effects of perinatal taurine treatment were attributed to an augmented H2S pathway, rebalance of aberrant RAAS activation, and gut microbiota alterations. In summary, our results not only deepen our knowledge of the mechanisms underlying maternal CKD-induced offspring hypertension but also afford us the impetus to consider taurine-based intervention as a promising preventive approach for future clinical translation.

Functional Role of Taurine in Aging and Cardiovascular Health: An Updated Overview

Taurine, a naturally occurring sulfur-containing amino acid, has attracted significant attention in recent years due to its potential health benefits. Found in various foods and often used in energy drinks and supplements, taurine has been studied extensively to understand its impact on human physiology. Determining its exact functional roles represents a complex and multifaceted topic. We provide an overview of the scientific literature and present an analysis of the effects of taurine on various aspects of human health, focusing on aging and cardiovascular pathophysiology, but also including athletic performance, metabolic regulation, and neurological function. Additionally, our report summarizes the current recommendations for taurine intake and addresses potential safety concerns. Evidence from both human and animal studies indicates that taurine may have beneficial cardiovascular effects, including blood pressure regulation, improved cardiac fitness, and enhanced vascular health. Its mechanisms of action and antioxidant properties make it also an intriguing candidate for potential anti-aging strategies.

Exploring the effects of Qijiao Shengbai capsule on leukopenic mice from the perspective of intestinbased on metabolomics and 16S rRNA sequencing

Qijiao Shengbai capsule (QJSB) is formulated according to the traditional Chinese medicine formula, its function is to nourish Qi and blood, improve the body's immunity. Leukopenia has been treated with it in clinical settings. However, the mechanism of leukopenia from the perspective of intestinal tract has not been reported. This study combined metabolomics and 16S rRNA sequencing technologies to investigate the mechanism of QJSB on leukopenia from the intestine. As a result of cyclophosphamide induction in mice, the results demonstrated that QJSB may greatly increase the quantity of peripheral leukocytes (including neutrophils). Meanwhile, QJSB had a restorative effect on the colon of leukopenic mice; it also increased the level of IL-2, IL-6 and G-CSF in the intestine, further enhancing the immunity and hematopoietic function of mice. Metabolic studies showed that QJSB altered 27 metabolites, most notably amino acid metabolism. In addition, QJSB had a positive regulatory effect on the intestinal microbiota, and could alter community composition by improving the diversity and abundance of the intestinal microbial, which mainly involved 6 related bacterial groups, and primarily regulates three associated SCFAs (acetic acid, butyrate acid and valeric acid). Therefore, this study suggests that QJSB can improve hematopoietic function, enhance the immune system, relieve leucopenia and improve the gut in leucopenic mice by modulating metabolic response pathways, fecal metabolites and intestinal microbiota.

A High-Fat, High-Cholesterol Diet Promotes Intestinal Inflammation by Exacerbating Gut Microbiome Dysbiosis and Bile Acid Disorders in Cholecystectomy

Patients with post-cholecystectomy (PC) often experience adverse gastrointestinal conditions, such as PC syndrome, colorectal cancer (CRC), and non-alcoholic fatty liver disease (NAFLD), that accumulate over time. An epidemiological survey further revealed that the risk of cholecystectomy is associated with high-fat and high-cholesterol (HFHC) dietary intake. Mounting evidence suggests that cholecystectomy is associated with disrupted gut microbial homeostasis and dysregulated bile acids (BAs) metabolism. However, the effect of an HFHC diet on gastrointestinal complications after cholecystectomy has not been elucidated. Here, we aimed to investigate the effect of an HFHC diet after cholecystectomy on the gut microbiota-BA metabolic axis and elucidate the association between this alteration and the development of intestinal inflammation. In this study, a mice cholecystectomy model was established, and the levels of IL-Iβ, TNF-α, and IL-6 in the colon were increased in mice fed an HFHC diet for 6 weeks. Analysis of fecal BA metabolism showed that an HFHC diet after cholecystectomy altered the rhythm of the BA metabolism by upregulating liver CPY7A1, CYP8B1, and BSEP and ileal ASBT mRNA expression levels, resulting in increased fecal BA levels. In addition, feeding an HFHC diet after cholecystectomy caused a significant dysbiosis of the gut microbiota, which was characterized by the enrichment of the metabolic microbiota involved in BAs; the abundance of pro-inflammatory gut microbiota and related pro-inflammatory metabolite levels was also significantly higher. In contrast, the abundance of major short-chain fatty acid (SCFA)-producing bacteria significantly decreased. Overall, our study suggests that an HFHC diet after cholecystectomy promotes intestinal inflammation by exacerbating the gut microbiome and BA metabolism dysbiosis in cholecystectomy. Our study also provides useful insights into the maintenance of intestinal health after cholecystectomy through dietary or probiotic intervention strategies.