Postmenopausal osteoporosis stems mainly from estrogen deficiency leading to a gut microbiome-dependent disruption of host systemic immunity. However, the underlying mechanisms of estrogen deficiency-induced bone loss remain elusive and novel pharmaceutical intervention strategies for osteoporosis are needed. Here we reveal that ovariectomy (ovx)-induced estrogen deficiency in C57BL/6 mice causes significant disruption of gut microbiota composition, consequently leading to marked destruction of intestinal barrier function and gut leakage. As a result, signals transportation between intestinal microbiota and T cells from the gut to bone marrow is identified to contribute to osteoclastogenesis in ovx mice. Notably, we show that icariside I (GH01), a novel small molecule naturally occurring in Herbal Epimedium, has potential to alleviate or prevent ovx-induced bone loss in mice through regulation of gut-bone signaling axis. We find that GH01 treatment can effectively restore the gut microbiota composition, intestinal barrier function and host immune status markedly altered in ovx mice, thus significantly ameliorating bone loss and osteoporosis. These findings not only provide systematic understanding of the gut-immunity-bone axis-associated pathophysiology of osteoporosis, but also demonstrate the high potential of GH01 for osteoporosis treatment by targeting the gut-bone signaling axis.

Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether, TCS) and triclocarban (3,4,4'-trichloro-carbanilide, TCC) are two antimicrobial agents commonly used for personal care products. Previous studies primarily focused on respective harmful effects of TCS and TCC. In terms of their structural similarities and differences, however, the structure-toxicity relationships on health effects of TCS and TCC exposure remain unclear. Herein, global 1H NMR-based metabolomics was employed to screen the changes of metabolic profiling in various biological matrices including liver, serum, urine, feces and intestine of mice exposed to TCS and TCC at chronic and acute dosages. Metagenomics was also applied to analyze the gut microbiota modulation by TCS and TCC exposure. Targeted MS-based metabolites quantification, histopathological examination and biological assays were subsequently conducted to supply confirmatory information on respective toxicity of TCS and TCC. We found that oral administration of TCS mainly induced significant liver injuries accompanied with inflammation and dysfunction, hepatic steatosis fatty acids and bile acids metabolism disorders; while TCC exposure caused marked intestine injuries leading to striking disruption of colonic morphology, inflammatory status and intestinal barrier integrity, intestinal bile acids metabolism and microbial community. These comparative results provide novel insights into structure-dependent mechanisms of TCS-induced hepatotoxicity and TCC-triggered enterotoxicity in mice.

Hesperetin-7-O-glucoside (Hes-7-G) is a typical flavonoid monoglucoside, which can be generated from hesperidin with the removal of rhamnose by hydrolysis. Untargeted and targeted metabolomics together with 16S rRNA gene sequencing were employed to explore the exact absorption site of Hes-7-G and its beneficial effect in mice. Intestinal 1H nuclear magnetic resonance (NMR)-based metabolomics screening showed that Hes-7-G is mainly metabolized in the small intestine of mice, especially the ileum segment. Quantification analysis of bile acids (BAs) in the liver, intestinal tract, feces, and serum of mice suggests that Hes-7-G intake accelerates the processes of biosynthesis and excretion of BAs, thus promoting digestion and lowing hepatic cholesterol and triglyceride. 16S rRNA gene sequencing reveals that Hes-7-G significantly elevates the diversity of the gut microbiota in mice, especially those bacteria associated with BA secondary metabolism. These results demonstrated that long-term dietary Hes-7-G plays beneficial roles in health by modulating the gut bacteria and BA metabolism in mice.

The sugar moieties of natural flavonoids determine their absorption, bioavailability, and bioactivity in humans. To explore structure-dependent bioactivities of quercetin, isoquercetin, and rutin, which have the same basic skeleton linking different sugar moieties, we systemically investigated the ameliorative effects of dietary these flavonoids on high-fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) of mice. Our results revealed that isoquercetin exhibits the strongest capability in improving NAFLD phenotypes of mice, including body and liver weight gain, glucose intolerance, and systemic inflammation in comparison with quercetin and rutin. At the molecular level, dietary isoquercetin markedly ameliorated liver dysfunction and host metabolic disorders in mice with NAFLD. At the microbial level, the three flavonoids compounds, especially isoquercetin, can effectively regulate the gut microbiota composition, such as genera Akkermansia, Bifidobacterium, and Lactobacillus, which were significantly disrupted in NAFLD mice. These comparative findings offer new insights into the structure-dependent activities of natural flavonoids for NAFLD treatment.

Background: Although therapeutic antibodies against immune checkpoints such as PD-1/PD-L1 have achieved unprecedented success in clinical tumor patients, there are still many patients who are ineffective or have limited responses to immune checkpoint blockade (ICB). Discovery of novel strategies for cancer immunotherapy including natural small molecules is needed. Methods: Owing to its extremely low content in Epimedium genus, we firstly constructed a microbial cell factory to enzymatically biosynthesize icariside I, a natural flavonoid monosaccharide from Herbal Epimedium. Using a combination of targeted MS-based metabolomics, flow cytometric analysis, and biological assays, the therapeutic potentials of icariside I were subsequently investigated in vivo and in vitro. Results: We find that icariside I markedly downregulates a series of intermediate metabolites such as kynurenine, kynurenic acid and xanthurenic acid and corresponding key enzymes involved in kynurenine-AhR pathway in both tumor cells and tumor-bearing mice. In vivo, oral administration of icariside I downregulates SLC7A8 and PAT4 transporters and AhR, thus inhibiting nuclear PD-1 in CTLs. Moreover, icariside I significantly upregulates CD8 + T cells in both peripheral blood and tumor tissues of tumor-bearing mice. Consequently, interferon-gamma (IFN-gamma) secreted by CD8 + T cells suppresses tumor growth through activation of JAK1-STAT1 signaling, thus inducing tumor cell apoptosis. Conclusions: These results suggest that icariside I could be an effective small molecule drug for tumor immu-notherapy by blocking kynurenine-AhR pathway and tumor immune escape.

Recent studies report that the gut microbiome can enhance systemic and antitumor immunity by modulating responses to antibody immunotherapy in melanoma patients. In this study, we found that icariside I, a novel anti-cancer agent isolated from Epimedium, significantly inhibited B16F10 melanoma growth in vivo through regulation of gut microbiota and host immunity. Oral administration of icariside I improved the microbiota community structure with marked restoration of Lactobacillus spp. and Bifidobacterium spp. abundance in the cecal contents of tumor-bearing mice. We also found that icariside I improves the levels of microbiota-derived metabolites such as short-chain fatty acids (SCFAs) and indole derivatives, consequently promoting repair of the intestinal barrier and reducing systemic inflammation of tumor-bearing mice. Icariside I exhibited strong immunological anti-tumor activity, directly manifested by up-regulation of multiple lymphocyte subsets including CD4+ and CD8+ T cells or NK and NKT cells in peripheral blood of tumor-bearing mice. Collectively, these results suggest that icariside I, via its microbiome remodeling and host immune regulation properties, may be developed as an anticancer drug.

Noncaloric artificial sweeteners (NAS) are extensively introduced into commonly consumed drinks and foods worldwide. However, data on the health effects of NAS consumption remain elusive. Saccharin and sucralose have been shown to pass through the human gastrointestinal tract without undergoing absorption and metabolism and directly encounter the gut microbiota community. Here, we aimed to identify a novel mechanism linking intestinal Akkermansia muciniphila and the aryl hydrocarbon receptor (AHR) to saccharin/sucralose-induced nonalcoholic fatty liver disease (NAFLD) in mice. Saccharin/sucralose consumption altered the gut microbial community structure, with significant depletion of A. muciniphila abundance in the cecal contents of mice, resulting in disruption of intestinal permeability and a high level of serum lipopolysaccharide, which likely contributed to systemic inflammation and caused NAFLD in mice. Saccharin/sucralose also markedly decreased microbiota-derived AHR ligands and colonic AHR expression, which are closely associated with many metabolic syndromes. Metformin or fructo-oligosaccharide supplementation significantly restored A. muciniphila and AHR ligands in sucralose-consuming mice, consequently ameliorating NAFLD. IMPORTANCE Our findings indicate that the gut-liver signaling axis contributes to saccharin/sucralose consumption-induced NAFLD. Supplementation with metformin or fructo-oligosaccharide is a potential therapeutic strategy for NAFLD treatment. In addition, we also developed a new nutritional strategy by using a natural sweetener (neohesperidin dihydrochalcone (NHDC)) as a substitute for NAS and free sugars.

Hesperetin-7-O-glucoside (Hes-7-G) is a naturally occurring flavonoid monoglucoside in Citri Reticulatae Pericarpium and exhibits relatively high biological activities. To explore the anti-inflammatory capacity of dietary Hes-7-G, lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and dextran sodium sulfate (DSS)-induced colitis mice were used here as in vitro and in vivo inflammation models. The results showed that Hes-7-G (5 μM) significantly restored cellular metabolic disorders and inflammation in LPS-stimulated RAW264.7 macrophages. In the in vivo study, dietary Hes-7-G (1 mg/kg body weight) markedly alleviated the inflammatory status in DSS-induced colitis mice, manifested by the recovered colon length from 5.91 ± 0.66 to 6.45 ± 0.17 cm, histopathological changes, and mRNA levels of colonic inflammatory factors including Tnf-α and Il-22. Furthermore, dietary Hes-7-G not only profoundly regulated the gut microbiota composition including phyla Bacteroidetes, Cyanobacteria, Desulfobacterota, and Deferribacteres and genus Enterorhabdus, Prevotellaceae, Gastranaerophilales, Enterococcus, Intestinimonas, Ruminococcaceae, and Eubacterium in the cecal contents but also especially adjusted the co-metabolites such as short chain fatty acids and indole metabolites (indole-3-propionic, indole acetic acid), which were markedly altered by DSS treatment in mice. These findings demonstrated that Hes-7-G has strong anti-inflammatory activity in vitro and in vivo and potential preventive or therapeutic effects for chronic inflammation diseases.

黄酮类化合物广泛存在于中草药、水果和蔬菜等植物中,具有多种生物效应,在诸如肥胖、糖尿病、癌症等多种代谢性疾病的改善和防治中起着很重要的作用.由于黄酮糖苷类天然产物是植物中黄酮类化合物的主要存在形式,常见的糖基配体有葡萄糖基、鼠李糖基、新橙皮糖基和芸香糖基,因此,糖基数目及其链接的位置决定了其在体内的吸收、分布、代谢和生物活性.与此同时,黄酮类化合物进入体内之后,与肠道微生物相互作用直接影响它们的代谢和生物活性.该文重点综述糖基化黄酮类化合物的体内吸收、与肠道菌群互相作用、生物活性及其在临床疾病中的应用.

As important signal metabolites within enterohepatic circulation, bile acids (BAs) play a pivotal role during the occurrence and development of diet-induced nonalcoholic fatty liver disease (NAFLD). Here, we evaluated the functional effects of BAs and gut microbiota contributing to sucralose consumption-induced NAFLD of mice. The results showed that sucralose consumption significantly upregulated the abundance of intestinal genera Bacteroides and Clostridium, which produced deoxycholic acid (DCA) accumulating in multiple biological matrixes including feces, serum, and liver of mice. Subsequently, elevated hepatic DCA, one of the endogenous antagonists of the farnesol X receptor (Fxr), inhibited hepatic gene expression including a small heterodimer partner (Shp) and Fxr leading to sucralose-induced NAFLD in mice. Dietary supplements with fructo-oligosaccharide or metformin markedly restored genera Bacteroides and Clostridium abundance and the DCA level of sucralose-consuming mice, which eventually ameliorated NAFLD. These findings highlighted the effects of gut microbiota and its metabolite DCA on sucralose-induced NAFLD of mice.

Drinking water exposure to microcystin-leucine-arginine (MC-LR), the most widely occurring cyanotoxins, poses a highly potential risk for human health. However, the health risk of MC-LR exposure at current guideline value in drinking water has not yet entirely evaluated. In the current study, we used 1H NMR-based metabolomics combined with targeted metabolic profiling by GC/LC-MS to explore the toxic effects of MC-LR exposure at environmentally relevant concentrations via drinking water in rats. The results revealed that multiple biological consequences of MC-LR exposure on host metabolism in rats. Both relatively low and high doses of MC-LR used here induced hepatic lipogenesis and inflammation. While only relatively high dose MC-LR (10 μg/L) in drinking water caused more metabolic disorders including inhibition of gluconeogenesis and promotion of β-oxidation of fatty acid. Although the dose of 1.0 μg/L MC-LR is extremely low for rats, alterations of metabolic profiles were unexpectedly found in rat liver and serum, alarming potential health risk of MC-LR at the WHO guideline level.

Hesperetin-7-O-glucoside (Hes-7-G) is a typical flavonoid monoglucoside isolated from Citri Reticulatae Pericarpium (CRP), which is commonly used as a food adjuvant and exhibits potential biological activities. To explore the interaction between Hes-7-G ingestion and microbiome and host metabolism, here, 16S rRNA gene sequencing was first used to analyze the alteration of fecal microbiome in mice after Hes-7-G intake. Metabolic homeostasis in mice was subsequently investigated using untargeted 1H NMR-based metabolomics and targeted metabolite profiling. We found that dietary Hes-7-G significantly regulated fecal microbiota and its derived metabolites, including short-chain fatty acids (SCFAs) and tryptophan metabolites (indole and its derivatives), in feces of mice. Regulation of microbiota was further confirmed by the significantly changed urinary hippurate and trimethylamine N-oxide (TMAO), co-metabolites of the microbe and host. We also found that dietary Hes-7-G modulated the host tricarboxylic acid cycle (TCA) involved in energy metabolism. These findings suggested that Hes-7-G exhibits potential beneficial effects for human health.

BackgroundEmerging evidence has shown that gut microbiome plays important roles in antitumor immunotherapy by shaping systemic immune responses. Specifically, Lactobacillus spp. and Bifidobacterium spp. were previously reported to enhance host immunity and inhibit tumor growth. Furthermore, microbiota-derived metabolites such as short-chain fatty acids (SCFAs) and indole derivatives are gradually regarded as immunomodulatory molecules involved in metabolic signaling pathways.MethodsA B16F10 melanoma model was selected as a tumor-bearing animal for the investigation of immunological anti-tumor activity of Icariside I. Gut microbiota structure and composition in cecal content of mice was firstly analyzed by 16S rRNA gene sequence with the goal of screening those bacteria highly associated with tumor immunotherapy. Subsequently, targeted metabolomics approach was employed to quantitatively determine microbiota-derived metabolites such as SCFAs and indole derivatives. The population of multiple lymphocyte subsets in peripheral blood were measured with flowcytometry to evaluate changes of host immunity.ResultsIcariside I significantly inhibited B16F10 melanoma growth in vivo through regulation of gut microbiota and host immune. Oral administration of icariside I improved the altered gut microbiota community with marked restoration of Lactobacillus spp. and Bifidobacterium spp. abundance. Icariside I was also able to improve the levels of microbiota-derived metabolites such as short-chain fatty acids (SCFAs) and indole derivatives, consequently repairing intestinal barrier and systemic inflammation of tumor-bearing mice. Furthermore, icariside I up-regulated multiple lymphocyte subsets including CD4 + and CD8 + T cells or NK and NKT cells in peripheral blood.ConclusionsThese results suggested that icariside I may be developed as a novel and natural anticancer adjuvant via microbiome remodeling and host immune regulation.

Triclocarban (TCC), a widely used antibacterial agent, has aroused considerable public concern due to its potential toxicity. In the current study, we applied targeted metabolite profiling (LC/GC-MS) and untargeted 1H NMR-based metabolomics in combination with biological assays to unveil TCC exposure-induced cellular metabolic responses in murine preadipocyte and human normal hepatocytes. We found that TCC promoted adipocyte differentiation in 3T3L1 preadipocytes, manifested by marked triglyceride (TG) and fatty acids accumulation, which were consistent with significant up-regulation of mRNA levels in the key adipogenic markers Fasn, Srebp1 and Ap2. In human hepatocytes (L02), TCC exposure dose-dependently interfered with the cellular redox state with down-regulated levels of antioxidant reduced-GSH and XBP1 and further induced the accumulation of TG, ceramides and saturated fatty acid (16:0). We also found that TCC exposure triggered unfold protein response (UPR) and endoplasmic reticulum (ER) stress in both cells through activation of ATF4 and ATF6, resulting in toxic lipid accumulation. These findings about lipid metabolism and metabolic responses to TCC exposure in both preadipocytes and hepatocytes provide novel perspectives for revealing the mechanisms of TCC toxicity.

We developed a J-compensated QHSQC NMR method for the quantitative measurement of enantiopurity and concentration of levofloxacin in a complex drug matrix. The pulse sequence can achieve uniform signal responses by the suppression of the heteronuclear coupling modulation and alleviation of the homonuclear coupling evolution. Furthermore, we discuss the influence of relaxation on peak intensities and propose the selection conditions of reference signals to achieve accurate quantifications. The evaluation of the methodology shows that the results obtained by selected peaks are in accordance with theoretical analysis with good reliability and linearity. The enantiomeric separation and quantification of levofloxacin in creams are achieved by using a chiral solvating agent, a reference compound, and the J-compensated QHSQC pulse sequence. To our knowledge, this is the first example of QHSQC methodology to quantify enantiomers in the complex matrix.

Environmental exposure to 2,3,7,8-tetrachlorodibenzofuran (TCDF), one of typical persistent organic pollutants (POPs) produced from municipal waste combustion, exerts toxic effects on human healthy. In the current study, we mainly used targeted metabolomics combined with untargeted 1H NMR-based metabolomics to investigate the effects of TCDF exposure on lipid homeostasis in mice. We found that TCDF exposure induced hepatic lipogenesis, the early-stage of non-alcoholic fatty liver disease, manifested by excessive lipids including triglycerides, fatty acids and lipotoxic ceramides accumulated in the liver together with elevated serum very low-density lipoprotein by activating the aryl hydrocarbon receptor (AHR) and its target genes such as Cyp1a1 and Cd36. We also found that TCDF exposure induced alteration of phospholipids and choline metabolites and endoplasmic reticulum (ER) markers in the liver of mice, indicating that disruption of host cell membrane structural integrity and ER stress leading to hepatic steatosis. In addition, complementary information was also obtained from histopathologic assessments and biological assays, strongly supporting toxic effects of TCDF. These results provide new evidence of TCDF toxicity associated with fatty liver disease and further our understanding of health effects of environmental pollutants exposure.