Project description:Background: As a worldwide threat to mental health, depression affects about 322 million people globally. Recently, the role of gut microbiota dysbiosis on the pathogenesis of depression has received widespread attention, but the underlying mechanism remains elusive.Results: Corticosterone (CORT)-treated mice showed depressive-like behaviors, a reduction in hippocampal neurogenesis, and an altered composition of gut microbiota (GM). Fecal microbial transplantation (FMT) from CORT-treated mice transferred depressive-like phenotypes and their dominant GM, especially bifidobacterium and lactobacillus, to the recipients. Fecal metabolic profiling showed that the relative abundances of fecal ceramides were significantly increased in CORT-treated and the recipient mice. Metagenomic sequencing exposed that bifidobacterium and lactobacillus might be responsible for gut ceramides production in CORT-treated mice. We then found that treatment with ceramides via oral gavage was sufficient to recapitulate the depressive-like phenotypes in wild -type mice. Finally, RNA-sequencing data exposed that most of the differentially expressed genes (DEGs) between ceramides-treated mice and the control group were enriched in oxidative phosphorylation (OXPHOS) pathway. Conclusion: We conclude that chronic exposure to CORT leads to an altered GM composition and consequent ceramides production, thus leading to subtle mitochondrial OXPHOS dysfunction in hippocampus, which may contribute to the development of depressive disorders.
Project description:Major depressive disorder is caused by gene-environment interactions and the gut microbiota plays a pivotal role in the development of depression. However, the mechanisms by which the gut microbiota modulates depression remain elusive. Herein, we detected the differentially expressed hippocampal long non-coding RNAs (lncRNAs), messenger RNAs (mRNAs) and microRNAs (miRNAs) between mice inoculated with gut microbiota from major depressive disorder patients or healthy controls, to identify the effects of gut microbiota-dysbiosis on gene regulation patterns at the transcriptome level. We also performed functional analysis to explore the microbial-regulated pathological mechanisms of depression. Two hundred mRNAs, 358 lncRNAs and 4 miRNAs were differentially expressed between the two groups. Functional analysis of these differentially expressed mRNAs indicated dysregulated inflammatory response to be the primary pathological change. Intersecting the differentially expressed mRNAs with targets of differentially expressed miRNAs identified 47 intersected mRNAs, which were mainly related to neurodevelopment. Additionally, we constructed a microbial-regulated lncRNA-miRNA-mRNA network based on RNA-RNA interactions. According to the competitive endogenous RNA hypothesis, two neurodevelopmental ceRNA sub-networks implicating in depression were identified. This study provides new understanding of the pathogenesis of depression induced by gut microbiota-dysbiosis and may act as a theoretical basis for the development of gut microbiota-based antidepressants.
Project description:Major depressive disorder is caused by gene-environment interactions and the gut microbiota plays a pivotal role in the development of depression. However, the mechanisms by which the gut microbiota modulates depression remain elusive. Herein, we detected the differentially expressed hippocampal long non-coding RNAs (lncRNAs), messenger RNAs (mRNAs) and microRNAs (miRNAs) between mice inoculated with gut microbiota from major depressive disorder patients or healthy controls, to identify the effects of gut microbiota-dysbiosis on gene regulation patterns at the transcriptome level. We also performed functional analysis to explore the microbial-regulated pathological mechanisms of depression. Two hundred mRNAs, 358 lncRNAs and 4 miRNAs were differentially expressed between the two groups. Functional analysis of these differentially expressed mRNAs indicated dysregulated inflammatory response to be the primary pathological change. Intersecting the differentially expressed mRNAs with targets of differentially expressed miRNAs identified 47 intersected mRNAs, which were mainly related to neurodevelopment. Additionally, we constructed a microbial-regulated lncRNA-miRNA-mRNA network based on RNA-RNA interactions. According to the competitive endogenous RNA hypothesis, two neurodevelopmental ceRNA sub-networks implicating in depression were identified. This study provides new understanding of the pathogenesis of depression induced by gut microbiota-dysbiosis and may act as a theoretical basis for the development of gut microbiota-based antidepressants.
Project description:We analyzed gut microbiota composition in stool, inflammation factor and short chain fatty acid (SCFAs) in plasma, inflammatory and permeability marker in intestinal mucosa in inflammatory depression patients.
Project description:Gut microbiota dysbiosis characterizes systemic metabolic alteration, yet its causality is debated. To address this issue, we transplanted antibiotic-free conventional wild-type mice with either dysbiotic (“obese”) or eubiotic (“lean”) gut microbiota and fed them either a NC or a 72%HFD. We report that, on NC, obese gut microbiota transplantation reduces hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non-transplanted mice. Of note, this phenotype is blunted in conventional NOD2KO mice. By contrast, lean microbiota transplantation did not affect hepatic gluconeogenesis. In addition, obese microbiota transplantation changed both gut microbiota and microbiome of recipient mice. Interestingly, hepatic gluconeogenesis, PEPCK and G6Pase activity were reduced even once mice transplanted with the obese gut microbiota were fed a 72%HFD, together with reduced fed glycaemia and adiposity compared to non-transplanted mice. Notably, changes in gut microbiota and microbiome induced by the transplantation were still detectable on 72%HFD. Finally, we report that obese gut microbiota transplantation may impact on hepatic metabolism and even prevent HFD-increased hepatic gluconeogenesis. Our findings may provide a new vision of gut microbiota dysbiosis, useful for a better understanding of the aetiology of metabolic diseases. all livers are from NC-fed mice only.
Project description:Accumulating evidence demonstrates that the gut microbiota affects brain function and behavior, including depressive behavior. Antidepressants are the main drugs used for treatment of depression. We hypothesized that antidepressant treatment could modify gut microbiota which can partially mediate their antidepressant effects. Mice were chronically treated with one of five antidepressants (fluoxetine, escitalopram, venlafaxine, duloxetine or desipramine), and gut microbiota was analyzed, using 16s rRNA gene sequencing. After characterization of differences in the microbiota, chosen bacterial species were supplemented to vehicle and antidepressant-treated mice, and depressive-like behavior was assessed to determine bacterial effects. RNA-seq analysis was performed to determine effects of bacterial treatment in the brain. Antidepressants reduced richness and increased beta diversity of gut bacteria, compared to controls. At the genus level, antidepressants reduced abundances of Ruminococcus, Adlercreutzia, and an unclassified Alphaproteobacteria. To examine implications of the dysregulated bacteria, we chose one of antidepressants (duloxetine) and investigated if its antidepressive effects can be attenuated by simultaneous treatment with Ruminococcus flavefaciens or Adlercreutzia equolifaciens. Supplementation with R. flavefaciens diminished duloxetine-induced decrease in depressive-like behavior, while A. equolifaciens had no such effect. R. flavefaciens treatment induced changes in cortical gene expression, up-regulating genes involved in mitochondrial oxidative phosphorylation, while down-regulating genes involved in neuronal plasticity. Our results demonstrate that various types of antidepressants alter gut microbiota composition, and further implicate a role for R. flavefaciens in alleviating depressive-like behavior.
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: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.