Stable Isotope Tracer Technique and Network Pharmacology to Reveal Antidepressant Targets and Active Components of Xiaoyao San.

In recent years, the research of mitochondrial dysfunction in depression has drawn the focus of researchers. Our research group previously found that Xiaoyao San (XYS) has improved the mitochondrial structure and the blocked tricarboxylic acid cycle (TCA cycle) in the hippocampal tissue of chronic unpredictable mild stress (CUMS) rats. However, the specific targets and active components of XYS remain unclear, and the potential to improve hippocampal mitochondrial TCA cycle disorder was also unexplored. In this research, a strategy to combine stable isotope-resolved metabolomics (SIRM), network pharmacology and transmission electron microscopy (TEM) was used to explore the potential, targets of action, and active components of XYS to improve hippocampal mitochondrial TCA cycle disorder of CUMS rats. The results of TEM showed that the ultrastructure of hippocampal mitochondria could be improved by XYS. A combination of SIRM and molecular docking showed that pyruvate carboxylase (PC), ATP citrate lyase (ACLK), glutamate dehydrogenase (GLDH), glutamate oxaloacetate transaminase (GOT) and pyruvate dehydrogenase (PDH) were targets of XYS to improve TCA cycle disorder. In addition, troxerutin was found to be the most potential active component of XYS to improve TCA cycle disorder. The above research results can provide new insights for the development of antidepressant drugs.

A novel insight for high-rate and low-efficiency glucose metabolism in depression through stable isotope-resolved metabolomics in CUMS-induced rats.

BACKGROUND: Existing research has suggested that depression results in disorders of glucose metabolism in the organism which causing insufficient energy supply. However, the overall changes in glucose metabolism that arise from depression have not been clarified. METHODS: In this study, the depression-like behavior in chronically unpredictable mild stressed rats was investigated, and the fate of glucose was tracked through isotope tracing and mass spectrometry, with a focus on metabolite changes in cecal contents. RESULTS: As indicated by the results, the isotopic results of cecal contents can indicate the metabolic end of the organism. Moreover, the TCA cycle activity was notably reduced, and the gluconeogenesis pathway was abnormally up-regulated in the CUMS-induced rats. The organism expedited other glucose metabolism pathways to make up for the insufficiency of energy. As a result, the activity of the inefficient glycolysis pathway was increased. LIMITATIONS: Existing research has only investigated the metabolism of 13C-glucose, and lipids and proteins have been rarely explored. CONCLUSIONS: The chronic unpredictable mild stress can inhibit the entry of pyruvate into mitochondria in SD rats, such that the activity of TCA is reduced, and insufficient energy supply is caused. The organism is capable of expediting other glucose metabolism rate pathways to make up for the insufficiency of energy, whereas it still cannot compensate for the loss of energy. As a result, CUMS-induced rats exhibited high-rate and low-efficiency glucose metabolism.

A unique insight for Xiaoyao San exerts antidepressant effects by modulating hippocampal glucose catabolism using stable isotope-resolved metabolomics.

ETHNOPHARMACOLOGICAL RELEVANCE: In traditional Chinese medicine (TCM) theory, depression is an emotional disease, which is thought to be related to stagnation of liver qi and dysfunction of the spleen in transport. Xiaoyao San (XYS) is considered to have the effects of soothing liver-qi stagnation and invigorating the spleen. The spleen has the function to transport and transform nutrients. The liver has also termed the center of energy metabolism in the body. Therefore, exploring the antidepressant effects of XYS from the perspective of energy metabolism may reveal new findings. AIM OF THE STUDY: Glucose catabolism is an important part of energy metabolism. In recent years, several researchers have found that XYS can exert antidepressant effects by modulating abnormalities in glucose catabolism-related metabolites. The previous research of our research group found that the hippocampus glucose catabolism was disordered in depression. However, the antidepressant potential of XYS through modulating the disorders of hippocampal glucose catabolism and the specific metabolic pathways and targets of XYS action were still unknown. The aim of this study was to address the above scientific questions. MATERIALS AND METHODS: In this research, the CUMS (chronic unpredictable mild stress) model was used as the animal model of depression. The antidepressant effect of XYS was evaluated by behavioral indicators. The specific pathways and targets of XYS modulating the disorders of glucose catabolism in the hippocampus of CUMS rats were obtained by stable isotope-resolved metabolomics. Further, the isotope tracing results were also verified by molecular biology and electron transmission electron microscopy. RESULTS: The results demonstrated that XYS pretreatment could significantly improve the depressive symptoms induced by CUMS. More importantly, it was found that XYS could modulate the disorders of glucose catabolism in the hippocampus of CUMS rats. Stable isotope-resolved metabolomics and enzyme activity tests showed that Lactate dehydrogenase (LDH), Pyruvate carboxylase (PC), and Pyruvate dehydrogenase (PDH) were targets of XYS for modulating the disorders of glucose catabolism in the hippocampus of CUMS rats. The Succinate dehydrogenase (SDH) and mitochondrial respiratory chain complex V (MRCC-Ⅴ) were targets of XYS to improve abnormal mitochondrial oxidative phosphorylation in the hippocampus of CUMS rats. XYS was also found to have the ability to improve the structural damage of mitochondria and nuclei in the hippocampal caused by CUMS. CONCLUSIONS: This study was to explore the antidepressant effect of XYS from the perspective of glucose catabolism based on a strategy combining stable isotope tracing, molecular biology techniques, and transmission electron microscopy. We not only obtained the specific pathways and targets of XYS to improve the disorders of glucose catabolism in the hippocampus of CUMS rats, but also revealed the specific targets of the pathways of XYS compared with VLF.

Stable Isotope-Resolved Metabolomics Studies on Corticosteroid-Induced PC12 Cells: A Strategy for Evaluating Glucose Catabolism in an in Vitro Model of Depression.

Depression is a common psychopathological state or mood disorder syndrome. The serious risks to human life and the inadequacy of the existing antidepressant drugs have driven us to understand the pathogenesis of depression from a new perspective. Our research group has found disturbances in glucose catabolism in both depression and nephrotic syndrome. What are the specific metabolic pathways and specificities of glucose catabolism disorders caused by depression? To address the above scientific questions, we creatively combined traditional metabolomics technology with stable isotope-resolved metabolomics to research the glucose catabolism of the corticosterone-induced PC12 cell damage model and the adriamycin-induced glomerular podocyte damage model. The results showed an increased flux of pyruvate metabolism in depression. The increased flux of pyruvate metabolism led to an activation of gluconeogenesis in depression. The disturbed upstream metabolism of succinate caused the tricarboxylic acid cycle (TCA cycle) to be blocked in depression. In addition, there were metabolic disturbances in the purine metabolism and pentose phosphate pathways in depression. Compared with nephrotic syndrome, pyruvate metabolism, the TCA cycle, and gluconeogenesis metabolism in depression were specific. The metabolic pathways researched above are likely to be important targets for the efficacy of antidepressants.

Stable Isotope-Resolved Metabolomics Reveals the Abnormal Brain Glucose Catabolism in Depression Based on Chronic Unpredictable Mild Stress Rats.

The severe harm of depression to human life has attracted great attention to neurologists, but its pathogenesis is extremely complicated and has not yet been fully elaborated. Here, we provided a new strategy for revealing the specific pathways of abnormal brain glucose catabolism in depression, based on the supply of energy substrates and the evaluation of the mitochondrial structure and function. By using stable isotope-resolved metabolomics, we discovered that the tricarboxylic acid cycle (TCA cycle) is blocked and gluconeogenesis is abnormally activated in chronic unpredictable mild stress (CUMS) rats. In addition, our results showed an interesting phenomenon that the brain attempted to activate all possible metabolic enzymes in energy-producing pathways, but CUMS rats still exhibited a low TCA cycle activity due to impaired mitochondria. Depression caused the mitochondrial structure and function to be impaired and then led to abnormal brain glucose catabolism. The combination of the stable isotope-resolved metabolomics and mitochondrial structure and function analysis can accurately clarify the mechanism of depression. The mitochondrial pyruvate carrier and acetyl-CoA may be the key targets for depression treatment. The strategy provides a unique insight for exploring the mechanism of depression, the discovery of new targets, and the development of ideal novel antidepressants. Data are available via ProteomeXchange with identifier PXD025548.

Comprehensive Analysis Strategy of Nervous-Endocrine-Immune-Related Metabolites to Evaluate Arachidonic Acid as a Novel Diagnostic Biomarker in Depression.

Depression is one of the most complex multifactorial diseases affected by genetic and environmental factors. The molecular mechanism underlying depression remains largely unclear. To address this issue, a novel nervous-endocrine-immune (NEI) network module was used to find the metabolites and evaluate the diagnostic ability of patients with depression. During this process, metabolites were acquired from a professional depression metabolism database. Over-representation analysis was performed using IMPaLA. Then, the metabolite-metabolite interaction (MMI) network of the NEI system was used to select key metabolites. Finally, the receiver operating characteristic curve analysis was evaluated for the diagnostic ability of arachidonic acid. The results show that the numbers of the nervous system, endocrine system, and immune system pathways are 10, 19, and 12 and the numbers of metabolites are 38, 52, and 13, respectively. The selected shared metabolite-enriched pathways can be 97.56% of the NEI-related pathways. Arachidonic acid was extracted from the NEI system network by using an optimization formula and validated by in vivo experiments. It was indicated that the proposed model was good at screening arachidonic acid for the diagnosis of depression. This method provides reliable evidences and references for the diagnosis and mechanism research of other related diseases.

A Novel Network Pharmacology Strategy to Decode Metabolic Biomarkers and Targets Interactions for Depression.

Depression is one of the most prevalent and serious mental disorders with a worldwide significant health burden. Metabolic abnormalities and disorders in patients with depression have attracted great research attention. Thirty-six metabolic biomarkers of clinical plasma metabolomics were detected by platform technologies, including gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance (1H-NMR), combined with multivariate data analysis techniques in previous work. The principal objective of this study was to provide valuable information for the pathogenesis of depression by comprehensive analysis of 36 metabolic biomarkers in the plasma of depressed patients. The relationship between biomarkers and enzymes were collected from the HMDB database. Then the metabolic biomarkers-enzymes interactions (MEI) network was performed and analyzed to identify hub metabolic biomarkers and enzymes. In addition, the docking score-weighted multiple pharmacology index (DSWMP) was used to assess the important pathways of hub metabolic biomarkers involved. Finally, validated these pathways by published literature. The results show that stearic acid, phytosphingosine, glycine, glutamine and phospholipids were important metabolic biomarkers. Hydrolase, transferase and acyltransferase involve the largest number of metabolic biomarkers. Nine metabolite targets (TP53, IL1B, TNF, PTEN, HLA-DRB1, MTOR, HRAS, INS and PIK3CA) of potential drug proteins for treating depression are widely involved in the nervous system, immune system and endocrine system. Seven important pathways, such as PI3K-Akt signaling pathway and mTOR signaling pathway, are closely related to the pathology mechanisms of depression. The application of important biomarkers and pathways in clinical practice may help to improve the diagnosis of depression and the evaluation of antidepressant effect, which provides important clues for the study of metabolic characteristics of depression.

Investigation on Endogenous Metabolites in Pancreas of Diabetic Rats after Treatment by Genipin through 1H-NMR-based Metabolomic Profiles / 中草药·英文版

Objective: To investigate the change rules of endogenous metabolites in pancreas of the diabetic rats, and to explore the mechanism of genipin treatment for diabetes rats. Methods: Metabolomic method based on 1H-NMR was applied, the diabetic rat model was prepared by ip injecting alloxan, and the high-, mid-, and low-dose genipin or metformin hydrochloride was ig injected as well as the rats in control and model groups were given the same volume of normal saline for 2 weeks. The pancreases of rats were collected and 1H-NMR test was conducted, the metabolomic technology was adopted to analyze the endogenous metabolite changes in pancreas. Results: The high-dose genipin possessed a better hypoglycemic effect, which could increase the contents of isoleucine, phosphatidylcholine, and phosphatidylethanolamine, and significantly reduce the contents of lactic acid, alanine, glutamine, aspartic acid, and creatine in pancreas of diabetic rats. Conclusion: This study provided a theoretical basis for further exploration on the pathogenesis of diabetes and the mechanism of genipin for treatment of diabetes.