Combined transcriptome and metabolome analyses of metformin effects reveal novel links between metabolic networks in steroidogenic systems.

Metformin is an antidiabetic drug, which inhibits mitochondrial respiratory-chain-complex I and thereby seems to affect the cellular metabolism in many ways. It is also used for the treatment of the polycystic ovary syndrome (PCOS), the most common endocrine disorder in women. In addition, metformin possesses antineoplastic properties. Although metformin promotes insulin-sensitivity and ameliorates reproductive abnormalities in PCOS, its exact mechanisms of action remain elusive. Therefore, we studied the transcriptome and the metabolome of metformin in human adrenal H295R cells. Microarray analysis revealed changes in 693 genes after metformin treatment. Using high resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS-NMR), we determined 38 intracellular metabolites. With bioinformatic tools we created an integrated pathway analysis to understand different intracellular processes targeted by metformin. Combined metabolomics and transcriptomics data analysis showed that metformin affects a broad range of cellular processes centered on the mitochondrium. Data confirmed several known effects of metformin on glucose and androgen metabolism, which had been identified in clinical and basic studies previously. But more importantly, novel links between the energy metabolism, sex steroid biosynthesis, the cell cycle and the immune system were identified. These omics studies shed light on a complex interplay between metabolic pathways in steroidogenic systems

On the modelling and regulation of the cardiovascular system: Applications in 1D & 3D

Baroreceptors are sensory cells that help the body to keep a constant aortic pressure by regulating cardiovascular parameters. The cardiovascular system can be modelled by several methods, comprising lumped parameter models which represent important parts of the body, or 3D models which are used to observe the local flow and pressure distribution. Current state of the art of modelling couples these models together in order to get more accurate 3D solutions in a computationally tractable manner. In the first part of this work, baroreflexes have been modelled using fuzzy controllers and inserted in a lumped parameter cardiovascular loop. Simulation results have shown the control of the system: The aortic pressure coming back to normal values after a slight perturbation imposed to the model, as long as this perturbation is within a physiological range. For strong perturbations, a limit of the baroreceptors was reached, corresponding to the natural regulation limit of the body. The second part of this work was to study the influence of boundary conditions imposed on the 3D models, with the final aim to couple the lumped parameter cardiovascular loop with a 3D model. Results showed different velocity and pressures distributions according to different boundary conditions. The most important result was the coupling of a 3D vessel with a cardiovascular loop, where several heart cycles were simulated: pressures and flows curves were stable over the different heart cycles. Barocontrollers were then inserted in this coupling, and showed the possibility to control the system if the initial pressure is higher than normal. Pressure regulation of a 1D-3D coupling model has been made. Next step could consist of replacing the straight pipe by the aortic arch, with some adjustments to the lumped parameter model. Moreover, an alternative 3D part of the cardiovascular loop, such as a valve, could be inserted in the syste

Sampling Method Affects HR-MAS NMR Spectra of Healthy Caprine Brain Biopsies

The metabolic profiling of tissue biopsies using high-resolution–magic angle spinning (HR-MAS) 1H nuclear magnetic resonance (NMR) spectroscopy may be influenced by experimental factors such as the sampling method. Therefore, we compared the effects of two different sampling methods on the metabolome of brain tissue obtained from the brainstem and thalamus of healthy goats by 1H HR-MAS NMR spectroscopy—in vivo-harvested biopsy by a minimally invasive stereotactic approach compared with postmortem-harvested sample by dissection with a scalpel. Lactate and creatine were elevated, and choline-containing compounds were altered in the postmortem compared to the in vivo-harvested samples, demonstrating rapid changes most likely due to sample ischemia. In addition, in the brainstem samples acetate and inositols, and in the thalamus samples ƴ-aminobutyric acid, were relatively increased postmortem, demonstrating regional differences in tissue degradation. In conclusion, in vivo-harvested brain biopsies show different metabolic alterations compared to postmortem-harvested samples, reflecting less tissue degradation. Sampling method and brain region should be taken into account in the analysis of metabolic profiles. To be as close as possible to the actual situation in the living individual, it is desirable to use brain samples obtained by stereotactic biopsy whenever possible

Metabolic Profiling of Cells in Response to Drug Treatment using 1H High-resolution Magic Angle Spinning (HR-MAS) NMR Spectroscopy

High-resolution magic angle spinning (HR-MAS) is an NMR technique that provides access to well resolved liquid-like 1H NMR spectra of semi-solid samples. Therefore, 1H HR-MAS NMR spectroscopy has become an important tool for the direct analysis of biological samples such as tissues and cells in a mostly non-destructive way. Here, we focus on the application of HR-MAS NMR combined with multivariate statistical methods used for metabolic profiling of cells and in particular for the study of cellular metabolic responses to drug exposure. The principles of HR-MAS and the metabolomic approach are briefly described. As an example, a study on the metabolic response of different cell types towards treatment with a highly cytotoxic hexacationic ruthenium metallaprism as potential anti-cancer drug is presented. Specific metabolites and metabolic pathways are suggested to be associated with the cellular response. The study demonstrates the potential of HR-MAS metabolomics applied to cells for addressing the intracellular processes involved in the treatment with organometallic drugs

Longitudinal investigation of the metabolome of 3D aggregating brain cell cultures at different maturation stages by H HR-MAS NMR.

The aim of the present study was to establish the developmental profile of metabolic changes of 3D aggregating brain cell cultures by H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy. The histotypic 3D brain aggregate, containing all brain cell types, is an excellent model for mechanistic studies including OMICS analysis; however, their metabolic profile has not been yet fully investigated. Chemometric analysis revealed a clear separation of samples from the different maturation time points. Metabolite concentration evolutions could be followed and revealed strong and various metabolic alterations. The strong metabolite evolution emphasizes the brain modeling complexity during maturation, possibly reflecting physiological processes of brain tissue development. The small observed intra- and inter-experimental variabilities show the robustness of the combination of H-HR-MAS NMR and 3D brain aggregates, making it useful to investigate mechanisms of toxicity that will ultimately contribute to improve predictive neurotoxicology. Graphical Abstract ᅟ