Metabolic signature of methylone in primary mouse hepatocytes, at subtoxic concentrations

Metabolomics based comprehensive investigation of Gardeniae Fructus induced hepatotoxicity

Gardeniae Fructus (Zhizi in Chinese, ZZ in brief), a commonly used herbal medicine, has aroused wide concern for hepatotoxicity, but the mechanism remains to be investigated. This study was aimed at investigating the mechanism of ZZ-induced liver injury in vivo and in vitro based on metabolomics and evaluating the hepatotoxicity prediction ability of the in vitro model. SD rats were administered with extracted ZZ and HepG2 cells were treated with genipin, the major hepatotoxic metabolite of ZZ. Liver, plasma, intracellular and extracellular samples were obtained for metabolomics analysis. As a result, ZZ caused plasma biochemical and liver histopathological alterations in rats, and induced purine and amino acid metabolism disorder in the liver and pyrimidine, primary bile acids, amino acid metabolism and pantothenate and CoA biosynthesis disorder in the plasma. Pyrimidine, purine, amino acid metabolism and pantothenate and CoA biosynthesis were also found to be disturbed in the genipin-treated HepG2 cells, which exhibited similarity with the result in vivo. This study comprehensively illustrates the underlying mechanism involved in ZZ-related hepatotoxicity from the aspect of metabolome, and provides evidence that identifying hepatotoxicity can be achieved in cells, representing a non-animal alternative for systemic toxicology.

Effect of temperature on 3,4-Methylenedioxypyrovalerone (MDPV)-induced metabolome disruption in primary mouse hepatic cells

3,4-Methylenedioxypyrovalerone (MDPV) is one of the most popular cathinone derivatives worldwide and has recently been associated with several intoxications and deaths, in which, similarly to amphetamines, hyperthermia appears to play a prominent role. However, there remains a huge information gap underlying the mechanisms associated with its hepatotoxicity, namely under hyperthermic conditions. Here, we use a sensitive untargeted metabolomic approach based on gas chromatography-mass spectrometry (GC-MS) to investigate the effect of subtoxic and toxic concentrations of MDPV on the metabolic profile of primary mouse hepatocytes (PMH), under normothermic and hyperthermic conditions. For this purpose, hepatocytes were exposed to increasing concentrations of MDPV (LC₀₁, LC₁₀ and LC₃₀) for 24 h, at 37 °C or 40.5 °C, and alterations on both intracellular metabolome and extracellular volatilome were evaluated. Multivariate analysis showed a clear separation between MDPV exposed cells and control cells in normothermic conditions, even at subtoxic concentrations (LC₀₁ and LC₁₀). In normothermia, there was a significant dysregulation of pathways associated with ascorbate metabolism, tricarboxylic acid (TCA) cycle and pyruvate metabolism. These metabolic changes were significantly increased at 40.5 °C, and several other pathways appear to be affected with the evolution of toxicity caused by MDPV under hyperthermic conditions, namely aspartate and glutamate metabolism, phenylalanine and tyrosine biosynthesis, aminoacyl-tRNA biosynthesis, butanoate metabolism, among others. Overall, our findings provide novel insights into the mechanism of hepatotoxicity triggered by MDPV and highlight the higher risks that may occur under hyperthermic conditions.

3,4-Methylenedioxymethamphetamine Hepatotoxicity under the Heat Stress Condition: Novel Insights from in Vitro Metabolomic Studies

Hyperthermia has been extensively reported as a life-threatening consequence of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) abuse. In this work, we used a sensitive untargeted metabolomic approach based on gas chromatography-mass spectrometry to evaluate the impact of hyperthermia on the hepatic metabolic changes caused by MDMA. For this purpose, primary mouse hepatocytes were exposed to subtoxic (LC₀₁ and LC₁₀) and toxic (LC₃₀) concentrations of MDMA for 24 h, at 37 or 40.5 °C (simulating body temperature increase after MDMA consumption), and alterations on both intracellular metabolome and extracellular volatilome were evaluated. Multivariate analysis showed that metabolic patterns clearly discriminate MDMA treated cells from control cells, both in normothermic and hyperthermic conditions. The metabolic signature was found to be largely common to MDMA subtoxic and toxic concentrations, although with evident differences in the magnitude of response, with metabolic changes significantly more pronounced at 40.5 °C. Discriminant metabolites associated with MDMA-induced hepatotoxicity are mostly involved in the amino acid metabolism, aminoacyl tRNA biosynthesis, glutathione metabolism, tricarboxylic acid cycle, and pyruvate metabolism. Moreover, our metabolomic findings were corroborated by classical toxicity parameters, demonstrating the high sensitivity of this omic approach to assess molecular-level effects. Overall, this study indicates that MDMA triggers significant metabolic alterations on hepatic cells, even at low concentrations, that are clearly exacerbated at high temperatures. These findings provide new metabolic pieces to solve the puzzle of MDMA's hepatotoxicity mechanism and emphasize the increased risks of MDMA abuse due to the thermogenic action of the drug.

Systematic impacts of chronic unpredictable mild stress on metabolomics in rats

Depression is the most common disabling psychiatric disease, with a high prevalence and mortality. Chronic unpredictable mild stress (CUMS) is a well-accepted method used to mimic clinical depression. Recent evidence has consistently suggested that the cumulative effects of CUMS could lead to allostatic overload in the body, thereby inducing systemic disorders; however, there are no previous systematic metabonomics studies on the main stress-targeted tissues associated with depression. A non-targeted gas chromatography–mass spectrometry (GC–MS) approach was used to identify metabolic biomarkers in the main stress-targeted tissues (serum, heart, liver, brain, and kidney) in a CUMS model of depression. Male Sprague–Dawley rats were randomly allocated to the CUMS group (n = 8) or a control group (n = 8). Multivariate analysis was performed to identify the metabolites that were differentially expressed between the two groups. There were 10, 10, 9, 4, and 7 differentially expressed metabolites in the serum, heart, liver, brain and kidney tissues, respectively, between the control and CUMS groups. These were linked to nine different pathways related to the metabolism of amino acids, lipids, and energy. In summary, we provided a comprehensive understanding of metabolic alterations in the main stress-targeted tissues, helping to understand the potential mechanisms underlying depression.