Indoleamine 2,3-Dioxygenase 1 Deletion-Mediated Kynurenine Insufficiency in Vascular Smooth Muscle Cells Exacerbates Arterial Calcification.

BACKGROUND: IDO1 (indoleamine 2,3-dioxygenase 1) is the rate-limiting enzyme for tryptophan metabolism. IDO1 malfunction is involved in the pathogenesis of atherosclerosis. Vascular smooth muscle cells (VSMCs) with an osteogenic phenotype promote calcification and features of plaque instability. However, it remains unclear whether aberrant IDO1-regulated tryptophan metabolism causes VSMCs osteogenic reprogramming and calcification. METHODS: We generated global Apoe (apolipoprotein E) and Ido1 double knockout mice, and Apoe knockout mice with specific deletion of IDO1 in VSMCs or macrophages. Arterial intimal calcification was evaluated by a Western diet-induced atherosclerotic calcification model. RESULTS: Global deficiency of IDO1 boosted calcific lesion formation without sex bias in vivo. Conditional IDO1 loss of function in VSMCs rather than macrophages promoted calcific lesion development and the abundance of RUNX2 (runt-related transcription factor 2). In contrast, administration of kynurenine via intraperitoneal injection markedly delayed the progression of intimal calcification in parallel with decreased RUNX2 expression in both Apoe-/- and Apoe-/-Ido1-/- mice. We found that IDO1 deletion restrained RUNX2 from proteasomal degradation, which resulted in enhanced osteogenic reprogramming of VSMCs. Kynurenine administration downregulated RUNX2 in an aryl hydrocarbon receptor-dependent manner. Kynurenine acted as the endogenous ligand of aryl hydrocarbon receptor, controlled resultant interactions between cullin 4B and aryl hydrocarbon receptor to form an E3 ubiquitin ligase that bound with RUNX2, and subsequently promoted ubiquitin-mediated instability of RUNX2 in VSMCs. Serum samples from patients with coronary artery calcification had impaired IDO1 activity and decreased kynurenine catabolites compared with those without calcification. CONCLUSIONS: Kynurenine, an IDO1-mediated tryptophan metabolism main product, promotes RUNX2 ubiquitination and subsequently leads to its proteasomal degradation via an aryl hydrocarbon receptor-dependent nongenomic pathway. Insufficient kynurenine exerts the deleterious role of IDO1 ablation in promoting RUNX2-mediated VSMCs osteogenic reprogramming and calcification in vivo.

Urinary metabolomics identified metabolic disturbance associated with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder. Nevertheless, its accurate mechanisms remain unclear. Metabolomics is a powerful technique to identify small molecules that could be used to discover pathogenesis and therapeutical targets of disease. In the present study, a urinary untargeted metabolomics combined with targeted quantification analysis was performed to uncover metabolic disturbance associated with PCOS. A total of thirty-eight metabolites were obtained between PCOS patients and healthy controls, which were mainly involved in lipids (39.5%), organic acids and derivatives (23.7%), and organic oxygen compounds (18.4%). Based on enrichment analysis, fourteen metabolic pathways were found to be perturbed in PCOS, particularly glycerophospholipid metabolism and tryptophan metabolism. Targeted quantification profiling of tryptophan metabolism demonstrated that seven compounds (tryptophan, kynurenine, kynurenic acid, quinolinic acid, xanthurenic acid, 3-hydroxyanthranilic acid and 3-hydroxykynurenine) were up-regulated in PCOS. And these tryptophan-kynurenine metabolites showed significant correlations with PCOS clinical features, such as positively associated with testosterone, free androgen index, and the ratio of luteinizing hormone to follicle stimulating hormone. Thus, this study disclosed urinary metabolome changes associated with PCOS, and might provide new insights into PCOS pathogenesis elucidation and therapeutical target development.

Rapid simultaneous determination of gut microbial phenylalanine, tyrosine, and tryptophan metabolites in rat serum, urine, and faeces using LC-MS/MS and its application to a type 2 diabetes mellitus study.

Gut microbial phenylalanine, tyrosine, and tryptophan metabolites are closely linked to various diseases. Monitoring the alterations of the related metabolites is vital to facilitate the understanding of pathophysiology of diseases. Herein, a rapid and sensitive assay based on LC-tandem mass spectrometry has been developed to analyze 20 gut microbial metabolites derived from phenylalanine, tyrosine, and tryptophan in rat serum, urine, and faeces. These microbial-derived metabolites were separated on a phenyl-hexyl column and simultaneously determined in a single run of 8 min. The detection limit for analytes ranged between 1.08 and 32.4 ng/mL. All calibration curves exhibited good linear relationships (R2 ≥ 0.9982). Intra- and inter-assay precision values were below 15% and accuracies ranged from 85% to 115% for all analytes. The selectivity, matrix effect, and recovery of this method were all satisfactory. The validated method was successfully applied to characterize the alterations of these metabolites in type 2 diabetes mellitus rat. In general, the developed assay is suitable for high-throughput monitoring of gut microbial phenylalanine, tyrosine, and tryptophan metabolites and provides a useful approach for exploring the mechanisms of microbial-derived metabolites in diseases.

Integrated microbiome-metabolomics analysis reveals the potential therapeutic mechanism of Zuo-Jin-Wan in ulcerative colitis.

BACKGROUND: Dysregulation in gut microbiota and host cometabolome contributes to the complicated pathology of ulcerative colitis (UC), while Zuo-Jin-Wan (ZJW), a traditional Chinese medicine has shown therapeutic effects against UC with its underlying mechanism remains elusive. PURPOSE: This study utilized an integrated analysis combining gut microbiome and host cometabolism to disclose the potential therapeutic mechanism of ZJW on dextran sulfate sodium (DSS)-induced UC in rats. METHODS: We first evaluated the therapeutic effects of ZJW treatment in DSS-induced rat model. 16S rRNA sequencing, 1H NMR spectroscopy-based metabolomics and Spearman correlation analysis were conducted to explore the potential therapeutic mechanism during the treatment. RESULTS: Our results showed that UC symptoms in ZJW rats were significantly attenuated. Marked decline in microbial diversity in ZJW group was accompanied by its correspondent function adjustment. Specific enrichment of genus Bacteroides, Sutterella, Akkermansia and Roseburia along with the major varying amino acid metabolism and lipid metabolism were observed meantime. Metabolic data further corroborated that ZJW-related metabolic changes were basically gathered in amino acid metabolism, carbohydrate/energy metabolism and lipid metabolism. Of note, some biochemical parameters were deeply implicated with the discriminative microbial genera and metabolites involved in tricarboxylic acid (TCA) cycle and amino acid metabolism, indicating the microbiome-metabolome association in gut microbiota-metabolite-phenotype axis during UC treatment of ZJW. CONCLUSION: For the first time, integrated microbiome-metabolome analysis depicted that ZJW could alleviate DSS-induced UC in rats via a crosstalk between gut microbiota and host cometabolites.

Structural Characterization and Immunoenhancing Effects of a Polysaccharide from the Soft Coral Lobophytum sarcophytoides.

Previous studies on the soft coral Lobophytum sarcophytoides (Lobophytum sp.) are mainly about small molecules, and there has been no systematic research on polysaccharides. In the study, a novel polysaccharide (LCPs-1-A) with immunoenhancing functions was successfully extracted and purified from the soft coral Lobophytum sp. After preliminary analysis, our data indicated that LCPs-1-A was composed of glucose and had a molecular weight of 4.90 × 106 Da. Moreover, our findings showed that LCPs-1-A could promote the proliferation and phagocytosis of RAW264.7 cells, stimulate the production of NO and ROS, and increase the mRNA expression of IL-1ß, IL-6, and TNF-α, which indicated that LCPs-1-A had a good immunoenhancing activity. Through further studies, we found that LCPs-1-A might play an immunoenhancing role through the TLR4/NF-κB signaling pathway. Therefore, our results demonstrated that LCPs-1-A might be a natural immunostimulant for use in medical and food industries.

Dietary synbiotic ameliorates constipation through the modulation of gut microbiota and its metabolic function.

The purpose of this study is to investigate the mitigatory effect of a novel synbiotic (SBT) on constipation from the perspective of gut microbiome and metabolome. Here, intake of SBT effectively attenuated diphenoxylate-induced constipation, recuperated colonic epithelial integrity and increased serum levels of gastrointestinal excitatory neurotransmitters (P substance, vasoactive intestinal peptide, motilin, gastrin and serotonin). 16S rRNA sequencing showed that SBT intake rehabilitated the composition and functionality of gut microbiota. Relative abundances of short-chain fatty acids (SCFAs)-producing bacteria including Lactobacillus, Faecalibaculum and Bifidobacterium were elevated by administration of SBT. The gas chromatography-mass spectrometry analysis confirmed that fecal concentrations of propionate and butyrate were significantly increased in the rats intervened with SBT. In addition, SBT ingestion reduced the relative levels of opportunistic pathogens, such as Oscillibacter, Parasutterella and Parabacteroides. Microbial functional prediction showed that the relative abundances of lipopolysaccharide (LPS) biosynthesis and arachidonic acid metabolism were downregulated with SBT administration, which were in accordance with the serum metabolomics results. Furthermore, serum levels of LPS, tumour necrosis factor alpha and interleukin 6 were significantly decreased, indicating that SBT supplementation suppressed inflammatory responses. Therefore, this study demonstrated that consumption of SBT ameliorated constipation possibly by regulating gut microbiota, promoting the SCFAs production and inhibiting inflammatory responses in rats. Our study also indicated that SBT may provide a novel alternative strategy for the treatment of constipation clinically in future.

Shenling Baizhu San improves functional dyspepsia in rats as revealed by 1H-NMR based metabolomics.

Functional dyspepsia (FD), a common gastrointestinal disorder around the world, is driven by multiple factors, making prevention and treatment a major challenge. Shenling Baizhu San (SBS), a classical prescription of traditional Chinese medicine, has been proven to be effective in gastrointestinal disorders. However, studies on SBS improving FD are few. Thus, our study aimed to evaluate the effect of SBS on FD and further to explore the mechanism underlying the interactions between FD and SBS by the metabolomics approach. A FD rat model was induced by multiple forms of mild stimulation, and proton nuclear magnetic resonance (1H-NMR) spectroscopy and multivariate data analysis were used to profile the fecal and urinary metabolome in the FD rats during SBS intervention. Significant dyspeptic symptoms such as weight loss, poor appetite, reduced gastrointestinal motility and decreased absorptive capacity were observed in the FD rats, which were subsequently improved by SBS. Additionally, the levels of citrate, branched chain acids and pyruvate decreased, and the levels of choline, trimethylamine and taurine increased in the FD rats. Furthermore, the metabolic disorders were amended with SBS intervention mainly by modulating the metabolic pathways involved in energy metabolism, amino acid metabolism, and gut microbiota and host co-metabolism. Overall, our study highlighted the effect of SBS on the disturbed metabolic pathways in the FD rats, providing new insight into the mechanism of SBS treatment for FD from the perspective of metabolomics.