Metabolomic and Lipidomic Analysis of Serum Samples following Curcuma longa Extract Supplementation in High-Fructose and Saturated Fat Fed Rats

International audienceWe explored, using nuclear magnetic resonance (NMR) metabolomics and fatty acids profiling, the effects of a common nutritional complement, Curcuma longa, at a nutritionally relevant dose with human use, administered in conjunction with an unbalanced diet. Indeed, traditional food supplements have been long used to counter metabolic impairments induced by unbalanced diets. Here, rats were fed either a standard diet, a high level of fructose and saturated fatty acid (HFS) diet, a diet common to western countries and that certainly contributes to the epidemic of insulin resistance (IR) syndrome, or a HFS diet with a Curcuma longa extract (1% of curcuminoids in the extract) for ten weeks. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) on the serum NMR profiles and fatty acid composition (determined by GC/MS) showed a clear discrimination between HFS groups and controls. This discrimination involved metabolites such as glucose, amino acids, pyruvate, creatine, phosphocholine/glycerophosphocholine, ketone bodies and gly-coproteins as well as an increase of monounsaturated fatty acids (MUFAs) and a decrease of n-6 and n-3 polyunsaturated fatty acids (PUFAs). Although the administration of Curcuma longa did not prevent the observed increase of glucose, triglycerides, cholesterol and insulin levels, discriminating metabolites were observed between groups fed HFS alone or with addition of a Curcuma longa extract, namely some MUFA and n-3 PUFA, glycoproteins, glutamine, and methanol, suggesting that curcuminoids may act respectively on the fatty acid metabolism, the hexosamine biosynthesis pathway and alcohol oxidation. Curcuma longa extract supplementation appears to be beneficial in these metabolic pathways in rats. This metabolomic approach highlights important serum metabolites that could help in understanding further the metabolic mechanisms leading to IR

Evaluation of the Rotating-Frame Relaxation ( T 1ρ ) Filter and Its Application in Metabolomics as an Alternative to the Transverse Relaxation ( T 2 ) Filter

International audienceNMR-based metabolomic studies commonly involve the use of T2-filter pulse sequences to eliminate or attenuate the broad signals from large molecules and improve spectral resolution. In this paper, we demonstrate that T1ρ filter-based pulse sequence represents an interesting alternative since it allows the stability and the reproducibility needed for statistical analysis. The integrity of the samples and the stability of the instruments were assessed for different filter durations and amplitudes. We showed that the T1ρ filter pulse sequence did not induce sample overheating for a filter duration up to 500 ms. The reproducibility was evaluated and compared with T2-filter in serum and liver samples. The implementation is relatively simple and provides the same statistical and analytical results as those obtained with the standard filters. Regarding tissues analysis, since the duration of the filter is that of the spin-lock, the synchronization of the echo delays with the Magic Angle Spinning (MAS) rate is no longer necessary as for T2 based filter sequences. The results presented in this article aim at establishing a new protocol to improve metabolomic studies and pave the way for future developments on T1ρ alternative filters, on liquid and HR-MAS NMR experiments

NMR-based metabolomic analysis of the physiological role of the electron-bifurcating FeFehydrogenase Hnd in Solidesulfovibrio fructosivorans under pyruvate fermentation

International audienceSolidesulfovibrio fructosivorans (formely Desulfovibrio fructosovorans), an anaerobic sulfate-reducing bacterium, possesses six gene clusters encoding six hydrogenases catalyzing the reversible oxidation of hydrogen gas (H2) into protons and electrons. One of these, named Hnd, was demonstrated to be an electronbifurcating hydrogenase Hnd (Kpebe et al., 2018). It couples the exergonic reduction of NAD + to the endergonic reduction of a ferredoxin with electrons derived from H2 and whose function has been recently shown to be involved in ethanol production under pyruvate fermentation (Payne 2022). To understand further the physiological role of Hnd in S. fructosivorans, we compared the mutant deleted of part of the hnd gene with the wild-type strain grown on pyruvate without sulfate using NMR-based metabolomics. Our results confirm that Hnd is profoundly involved in ethanol metabolism, but also indirectly intervenes in global carbon metabolism and additional metabolic processes such as the biosynthesis of branched-chain amino acids. We also highlight the metabolic reprogramming induced by the deletion of hndD that leads to the upregulation of several NADP-dependent pathways. Highlights • Metabolomics characterized pathways of pyruvate fermentation in S. fructosivorans • Hnd is involved in ethanol metabolism and branched-chain amino acid biosynthesis. • HndD deletion leads to the upregulation of NADP-dependent pathways

Hepatic metabolic effects of Curcuma longa extract supplement in high-fructose and saturated fat fed rats

International audienceThe metabolic effects of an oral supplementation with a Curcuma longa extract, at a dose nutritionally relevant with common human use, on hepatic metabolism in rats fed a high fructose and saturated fatty acid (HFS) diet was evaluated. High-resolution magic-angle spinning NMR and GC/MS in combination with multivariate analysis have been employed to characterize the NMR metabolite profiles and fatty acid composition of liver tissue respectively. The results showed a clear discrimination between HFS groups and controls involving metabolites such as glucose, glycogen, amino acids, acetate, choline, lysophosphatidylcholine, phosphatidylethanolamine, and β-hydroxybutyrate as well as an increase of MUFAs and a decrease of n-6 and n-3 PUFAs. Although the administration of CL did not counteract deleterious effects of the HFS diet, some metabolites, namely some n-6 PUFA and n-3 PUFA, and betaine were found to increase significantly in liver samples from rats having received extract of curcuma compared to those fed the HFS diet alone. This result suggests that curcuminoids may affect the transmethylation pathway and/or osmotic regulation. CL extract supplementation in rats appears to increase some of the natural defences preventing the development of fatty liver by acting on the choline metabolism to increase fat export from the liver

Fatty acid composition of serum.

<p>Relative fatty acid composition (% of total) and estimated desaturase activities in serum of rats fed control, HFS and HFS+C diets. Values are mean ± S.E.M (n = 6–12 rats/group). Samples were measured in duplicate. ∑ SFA total saturated fatty acids, ∑ PUFA total polyunsaturated fatty acids, ∑ MUFA total monounsaturated fatty acids, Δ estimated desaturase activity.</p><p>^a significantly different from control group</p><p>^b significantly different from HFS group; after multiple comparison tests and Bonferroni adjustment of the significance level.</p><p>Fatty acid composition of serum.</p

Results of serum biochemical analysis after 10 weeks of diet.

<p>Relative liver weight is defined as liver weight divided by body weight. Values are mean ± S.E.M (n = 6–12 rats/group).</p><p>*P < 0.05 vs. the control</p><p>**P < 0.01 vs. the control.</p><p>Results of serum biochemical analysis after 10 weeks of diet.</p

PCA score plot of the serum samples from Control, HFS and HFS+C groups.

<p>PCA score plot of the serum samples from Control, HFS and HFS+C groups.</p

Composition of the diets and fatty acid profile.

<p>∑ SFA = total saturated fatty acids, ∑ MUFA = total monounsaturated fatty acids, ∑ PUFA = total polyunsaturated fatty acids.</p><p>Composition of the diets and fatty acid profile.</p

Significantly differential metabolites in the rat serum of control, HFS and HFS+C group.

<p>The serum metabolites that contributed significantly to the discrimination between the different diets in the OPLS-DA model from the ¹H NMR data. ↑ (or ↓) denotes the relative increased (or decreased), followed by fold change in metabolite level (p < 0.05). The levels were calculated from relative intensities of ¹H NMR spectra following spectral normalization.</p><p>Significantly differential metabolites in the rat serum of control, HFS and HFS+C group.</p

Measurements of lipid peroxidation, total antioxidant capacity of serum after 10 weeks of diet.

<p>^a Malondialdehyde</p><p>^b oxygen radical absorbance capacity.</p><p>Values are mean ± S.E.M (n = 6–12 rats/group).</p><p>*p < 0.05 vs. the control.</p><p>Measurements of lipid peroxidation, total antioxidant capacity of serum after 10 weeks of diet.</p