Project description:Gut microbiota has profound effects on obesity and associated metabolic disorders. Targeting and shaping the gut microbiota via dietary intervention using probiotics, prebiotics and synbiotics can be effective in obesity management. Despite the well-known association between gut microbiota and obesity, the microbial alternations by synbiotics intervention, especially at the functional level, are still not characterized. In this study, we investigated the effects of synbiotics on high fat diet (HFD)-induced metabolic disorders, and systematically profiled the microbial profile at both the phylogenetic and functional levels. Synbiotics significantly reversed the HFD-induced change of microbial populations at the levels of richness, taxa and OTUs. Potentially important species Faecalibaculum rodentium and Alistipes putredinis that might mediate the beneficial effects of synbiotics were identified. At the functional level, short chain fatty acid and bile acid profiles revealed that interventions significantly restored cecal levels of acetate, propionate, and butyrate, and synbiotics reduced the elevated total bile acid level. Metaproteomics revealed the effect of synbiotics might be mediated through pathways involved in carbohydrate, amino acid, and energy metabolisms, replication and repair, etc. These results suggested that dietary intervention using our novel synbiotics alleviated HFD-induced weight gain and restored microbial ecosystem homeostasis phylogenetically and functionally.
Project description:Background: Acute pancreatitis (AP) is a common severe digestive disorder, with severity linked to high-fat diets (HFD). HFD may exacerbate AP by promoting inflammation and altering gut microbiota. Astragalus polysaccharides (APS) possess anti-inflammatory properties, but it is unclear if APS supplementation can mitigate HFD's detrimental effects on AP by modulating gut microbiota. This study investigates the mechanisms by which APS improves HFD-induced AP exacerbation. In this study, C57BL/6 mice were fed HFD or a standard diet, with or without APS, for 12 weeks. AP was induced via intraperitoneal caerulein injection. Analyses included ELISA, Western blotting, histology, immunohistochemistry, immunofluorescence, single-cell RNA sequencing (scRNA-seq), 16S rRNA sequencing of gut microbiota, and short-chain fatty acid (SCFA) analysis to evaluate inflammation and cellular changes. Results: HFD significantly increased AP severity, indicated by elevated serum enzyme and pro-inflammatory cytokine levels, along with extensive pancreatic damage. Single-cell RNA sequencing (scRNA-seq) showed a notable rise in ICAM1+ neutrophils and activation of the NF-κB/necroptosis pathway in HAP mice. APS alleviated these effects by decreasing ICAM1+ neutrophil infiltration, downregulating the NF-κB pathway, and reducing necroptosis. Moreover, APS restored gut microbiota balance, significantly boosting Lactobacillus reuteri (L. reuteri) abundance and propionate (PA) levels. Treatments with L. reuteri and PA independently mitigated HFD-induced AP severity, indicating that APS's protective effects are microbiota-dependent. Conclusion: APS improves HFD-induced gut dysbiosis and intestinal barrier dysfunction by enriching L. reuteri and PA, effectively reducing AP exacerbation. Our findings highlight the gut-pancreas axis as a promising target for addressing AP severity.
Project description:Intracerebral hemorrhage (ICH) induces alterations in the gut microbiota composition, significantly impacting neuroinflammation post-ICH. However, the impact of gut microbiota absence on neuroinflammation following ICH-induced brain injury remain unexplored. Here, we observed that the gut microbiota absence was associated with reduced neuroinflammation, alleviated neurological dysfunction, and mitigated gut barrier dysfunction post-ICH. In contrast, recolonization of microbiota from ICH-induced SPF mice by transplantation of fecal microbiota (FMT) exacerbated brain injury and gut impairment post-ICH. Additionally, microglia with transcriptional changes mediated the protective effects of gut microbiota absence on brain injury, with Apoe emerging as a hub gene. Subsequently, Apoe deficiency in peri-hematomal microglia was associated with improved brain injury. Finally, we revealed that gut microbiota influence brain injury and gut impairment via gut-derived short-chain fatty acids (SCFA).
Project description:Germfree (GF) mice have been used as a model to study the contribution of the intestinal microbiota to metabolic energy balance of the host. Despite a wealth of knowledge accumulated since the 1940’s, the response of GF mice to a high fat diet is largely unknown. In the present study, we compared the metabolic consequences of a high fat (HF) diet on GF and conventional (Conv) C57BL/6J mice. As expected, Conv mice developed obesity and glucose intolerance with a HF diet. In contrast, GF mice remained lean and resisted the HF diet-induced insulin resistance. The anti-obesity phenotype of GF/HF mice was accompanied by reduced caloric intake, diminished food efficiency, and excessive fecal lipid excretion contributed to the reduced food efficiency. In addition, HF diet-induced hypercholesterolemia was ameliorated, which was partially due to an increase in fecal cholesterol excretion. However, hepatic cholesterols were increased in GF/HF mice. Elevated nuclear SREBP2 proteins and the up-regulation of cholesterol biosynthesis genes support the increased liver cholesterol biosynthesis in GF/HF mice. The resistance to HF diet-induced metabolic abnormalities in GF mice was also associated with a reduced immune response, indicated by low plasma pro-inflammatory and anti-inflammatory markers. These data suggest that the gut microbiota of Conv mice contributes to HF diet-induced obesity, insulin resistance, dyslipidemia and hepatic steatosis in mice. Thus, results of the present study describe the metabolic responses of GF mice to a HF diet and further our understandings of the relationship between the gut microbiota and the host. Germfree and conventional C57BL/6J mice were fed with a high fat diet for 11 weeks. Then, all mice were sacrified under 10-h food deprevation, and liver samples of germfree (n=14) and conventional (n=16) were examined.
Project description:Obesity and overweight are closely related to diet, and gut microbiota play an important role in body weight and human health. The aim of this study was to explore how Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 supplementation alleviate obesity by modulating the human gut microbiome. A randomized, double-blind, placebo-controlled study was conducted on 72 overweight individuals. Over a 12-week period, probiotic groups consumed 5×10^9 colony-forming units of HY7601 and KY1032), whereas the placebo group consumed the same product without probiotics. After treatment, the probiotic group displayed a reduction in body weight (p <0.001), visceral fat mass (p <0.025), and waist circumference (p <0.007), and an increase in adiponectin (p <0.046), compared with the placebo group. Additionally, HY7601 and KY1032 supplementation modulated bacterial gut microbiota characteristics and beta diversity by increasing Bifidobacteriaceae and Akkermansiaceae, and decreasing Prevotellaceae and Selenomonadaceae. In summary, HY7601 and KY1032 probiotics exert anti-obesity effects by regulating the gut microbiota; hence, they have therapeutic potential for preventing or alleviating obesity and overweight.
Project description:In recent years, the gut microbiota and derived metabolites have emerged as relevant players in modulating several brain functions, including energy balance control. This form of distant communication mirrors that of metabolic hormones (e.g., leptin, ghrelin), that convey information about the organism's energy status by exerting effects on diverse brain regions including the master homeostatic centre the hypothalamus. However, whether the hypothalamus is also able to influence gut microbiota composition remains enigmatic. Here, we present a proof-of-concept study designed to unravel this challenging question. To this aim, we employed chemogenetics (to selectively activate or inhibit the activity of hypothalamic POMC or AgRP neurons) or administered leptin or ghrelin centrally to mice. Subsequently, we conducted microbiota composition analysis throughout the gut using 16S rRNA gene sequencing. Our results showed that these brain interventions significantly changed the gut microbiota in an anatomical and short-term (2-4h) fashion. Transcriptomic analysis indicated that these changes were associated with the reconfiguration of neuronal and synaptic pathways in the duodenum concomitant with increased sympathetic tone. Interestingly, diet-induced obesity attenuated brain-mediated changes induced by leptin in gut microbiota communities and sympathetic activation. Our findings reveal a novel and unanticipated brain-to-gut axis that acutely attunes microbiota composition at fast timescales, with potential implications for meal-to-meal adjustments and systemic energy balance control.
Project description:We studied the effect of dietary fat type, varying in polyunsaturated/saturated fatty acid ratio's (P/S) on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1) or safflower oil (HF-SO; P/S 7.8) for 8 weeks. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared to the HF-OO, HF-SO or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes/Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis. Keywords: Diet intervention study Nine-week-old C57Bl/6J mice were fed a low-fat diet (LF-PO) and three different types of high-fat diet, based on palm oil (HF-PO; P/S1.0), olive oil (HF-OO; P/S4.6) and safflower oil (HF-SO; P/S10.1) for 8 weeks. Body weight was recorded weekly and after 7 weeks of diet intervention an oral glucose tolerance test was performed. After 2 weeks of diet intervention, 6 mice per high-fat diet group were anaesthetized with a mixture of isofluorane (1.5%), nitrous oxide (70%) and oxygen (30%) and the small intestines were excised. Adhering fat and pancreatic tissue were carefully removed. The small intestines were divided in three equal parts along the proximal to distal axis (SI 1, SI 2 and SI 3) and microarray analysis was performed on mucosal scrapings.
Project description:Background: The long-term high-fat, high-sugar diet exacerbates type 2 diabetes mellitus (T2DM)-related cognitive impairments. The negative impact of poor dietary patterns on brain development and neurological function may be related to gut microbiota disturbance. The role of phlorizin in mitigating glucose and lipid metabolism disorders is well documented. However, the protective effect of phlorizin on diabetes-related cognitive dysfunction is unclear. Therefore, the present study aimed to investigate the effect of dietary supplementation of phlorizin on high-fat and high-fructose diet (HFFD)-induced cognitive dysfunction and evaluate the crucial role of the microbiota-gut-brain axis. Results: Dietary supplementation of phlorizin for 14 weeks effectively prevented glucolipid metabolism disorder, spatial learning impairment, and memory impairment in HFFD mice. In addition, phlorizin improved the HFFD-induced decrease in synaptic plasticity, neuroinflammation, and excessive activation of microglia in the hippocampus. Transcriptomics analysis shows that the protective effect of phlorizin on cognitive impairment was associated with increased expression of neurotransmitters and synapse-related genes in the hippocampus. Phlorizin treatment alleviated colon microbiota disturbance, mainly manifested by an increase in gut microbiota diversity and the abundance of short-chain fatty acid (SCFA)-producing bacteria. The level of microbial metabolites, including SCFA, inosine 5'-monophosphate (IMP), and D (-)-beta-hydroxybutyric acid (BHB) were also significantly increased after phlorizin treatment. Moreover, integrating multiomics analysis observed tight connections between phlorizin-regulated genes, microbiota, and metabolites. Furthermore, removal of the gut microbiota via antibiotics treatment diminished the protective effect of phlorizin against HFFD-induced cognitive impairment, underscoring the critical role of the gut microbiota in mediating cognitive behavior. Importantly, supplementation with SCFA and BHB alone mimicked the regulatory effects of phlorizin on cognitive function. Conclusions: These results indicate that gut microbiota and their metabolites mediate the ameliorative effect of phlorizin on HFFD-induced cognitive impairment. Therefore, phlorizin can be used as an easy-to-implement nutritional therapy to prevent and alleviate metabolism-related neurodegenerative diseases by targeting the regulation of the microbiome-gut-brain axis.
Project description:Aconitate decarboxylase 1 (ACOD1) is the enzyme synthesizing itaconate, an immuno-regulatory metabolite tuning host-pathogen interactions. Such functions are achieved by affecting metabolic pathways regulating inflammation and microbe survival. However, at the whole-body level, metabolic roles of itaconate remain largely unresolved. By using multiomics-integrated approaches, here we show that ACOD1 responds to high-fat diet consumption in mice by promoting gut microbiota alterations supporting metabolic disease. Genetic disruption of itaconate biosynthesis protects mice against obesity, alterations in glucose homeostasis and liver metabolic dysfunctions by decreasing meta-inflammatory responses to dietary lipid overload. Mechanistically, fecal metagenomics and microbiota transplantation experiments demonstrate such effects are dependent on an amelioration of the intestinal ecosystem composition, skewed by high-fat diet feeding towards obesogenic phenotype. In particular, unbiased fecal microbiota profiling and axenic culture experiments point towards a primary role for itaconate in inhibiting growth of Bacteroidaceae and Bacteroides, family and genus of Bacteroidetes phylum, the major gut microbial taxon associated with metabolic health. Specularly to the effects imposed by Acod1 deficiency on fecal microbiota, oral itaconate consumption enhances diet-induced gut dysbiosis and associated obesogenic responses in mice. Unveiling an unrecognized role of itaconate, either endogenously produced or exogenously administered, in supporting microbiota alterations underlying diet-induced obesity in mice, our study points ACOD1 as a target against inflammatory consequences of overnutrition.
Project description:We studied the effect of dietary fat type, varying in polyunsaturated/saturated fatty acid ratio's (P/S) on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1) or safflower oil (HF-SO; P/S 7.8) for 8 weeks. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared to the HF-OO, HF-SO or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes/Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis. Keywords: Diet intervention study