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Background and objectives: Non-alcoholic fatty liver disease (NAFLD) develops due to impaired hepatic lipid fluxes and is a risk factor for chronic liver disease and atherosclerosis. Lipidomic studies consistently reported characteristic hepatic/VLDL “lipid signatures” in NAFLD; whole plasma traits are more debated. Surprisingly, the HDL lipid composition by mass spectrometry has not been characterised across the NAFLD spectrum, despite HDL being a possible source of hepatic lipids delivered from peripheral tissues alongside free fatty acids (FFA). This study characterises the HDL lipidomic signature in NAFLD, and its correlation with metabolic and liver disease markers. Methods: We used liquid chromatography-mass spectrometry to determine the whole serum and HDL lipidomic profile in 89 biopsy-proven NAFLD patients and 20 sex and age-matched controls. Results: In the whole serum of NAFLD versus controls, we report a depletion in polyunsaturated (PUFA) phospholipids (PL) and FFA; with PUFA PL being also lower in HDL, and negatively correlated with BMI, insulin resistance, triglycerides, and hepatocyte ballooning. In the HDL of the NAFLD group we also describe higher saturated ceramides, which positively correlate with insulin resistance and transaminases. Conclusion: NAFLD features lower serum lipid species containing polyunsaturated fatty acids; the most affected lipid fractions are FFA and (HDL) phospholipids; our data suggest a possible defect in the transfer of PUFA from peripheral tissues to the liver in NAFLD. Mechanistic studies are required to explore the biological implications of our findings addressing if HDL composition can influence liver metabolism and damage, thus contributing to NAFLD pathophysiology.

Background Little is known about changes in blood fatty acid compositions over time and the correlates of any changes in a general population. Objective The aim of this study was to estimate changes in 27 individual plasma phospholipid fatty acids and fatty acid groups over time, and to identify potential correlates of these changes. Methods Plasma phospholipid fatty acids were profiled at 3 time-points (1993–1997, 1998–2000, 2004–2011) among 722 participants in the European Prospective Investigation into Cancer and Nutrition-Norfolk Study, UK. Linear regression models were used to estimate both 1) mean changes over time in 27 individual fatty acids and 8 prespecified fatty acid groups and 2) associations of changes in dietary and lifestyle factors with changes in the 8 fatty acid groups, mutually adjusted for dietary/lifestyle factors and other confounders. The prespecified fatty acid groups were odd-chain saturated fatty acids (SFAs), even-chain SFAs, very-long-chain SFAs, marine n–3 polyunsaturated fatty acids (PUFAs), plant n–3 PUFA, n–6 PUFAs, monounsaturated fatty acids (MUFAs), and trans-fatty acids (TFAs). Results Adjusted for confounders, fatty acid concentrations decreased for odd-chain SFAs (annual percentage difference in mol percentage: −0.63%), even-chain SFAs (−0.05%), n–6 PUFAs (−0.25%), and TFAs (−7.84%). In contrast, concentrations increased for marine n–3 PUFAs (1.28%) and MUFAs (0.45%), but there were no changes in very-long-chain SFAs or plant n–3 PUFA. Changes in fatty acid levels were associated with consumption of different food groups. For example, a mean 100 g/d increase in fatty fish intake was associated with a 19.3% greater annual increase in marine n–3 PUFAs. Conclusions Even-chain SFAs and TFAs declined and marine n–3 PUFAs increased over time. These changes were partially explained by changes in dietary habits, and could potentially help interpret associations of baseline fatty acid composition with future disease risk.

BACKGROUND: Presumed benefits of human milk (HM) in avoiding rapid infancy weight gain and later obesity could relate to its nutrient composition. However, data on breast milk composition and its relation with growth are sparse. OBJECTIVE: We investigated whether short-chain fatty acids (SCFAs), known to be present in HM and linked to energy metabolism, are associated with infancy anthropometrics. METHODS: In a prospective birth cohort, HM hindmilk samples were collected from 619 lactating mothers at 4-8 wk postnatally [median (IQR) age: 33.9 (31.3-36.5) y, body mass index (BMI) (kg/m2): 22.8 (20.9-25.2)]. Their offspring, born at 40.1 (39.1-41.0) wk gestation with weight 3.56 (3.22-3.87) kg and 51% male, were assessed with measurement of weight, length, and skinfold thickness at ages 3, 12, and 24 mo, and transformed to age- and sex-adjusted z scores. HM SCFAs were measured by 1H-nuclear magnetic resonance spectroscopy (NMR) and GC-MS. Multivariable linear regression models were conducted to analyze the relations between NMR HM SCFAs and infancy growth parameters with adjustment for potential confounders. RESULTS: NMR peaks for HM butyrate, acetate, and formic acid, but not propionate, were detected. Butyrate peaks were 17.8% higher in HM from exclusively breastfeeding mothers than mixed-feeding mothers (P = 0.003). HM butyrate peak values were negatively associated with changes in infant weight (standardized B = -0.10, P = 0.019) and BMI (B = -0.10, P = 0.018) between 3 and 12 mo, and negatively associated with BMI (B = -0.10, P = 0.018) and mean skinfold thickness (B = -0.10, P = 0.049) at age 12 mo. HM formic acid peak values showed a consistent negative association with infant BMI at all time points (B < = -0.10, P < = 0.014), whereas HM acetate was negatively associated with skinfold thickness at 3 mo (B = -0.10, P = 0.028) and 24 mo (B = -0.10, P = 0.036). CONCLUSIONS: These results suggest that HM SCFAs play a beneficial role in weight gain and adiposity during infancy. Further knowledge of HM SCFA function may inform future strategies to support healthy growth.

BackgroundInfantile beriberi-related mortality is still common in South and Southeast Asia. Interventions to increase maternal thiamine intakes, and thus human milk thiamine, are warranted; however, the required dose remains unknown.ObjectivesWe sought to estimate the dose at which additional maternal intake of oral thiamine no longer meaningfully increased milk thiamine concentrations in infants at 24 wk postpartum, and to investigate the impact of 4 thiamine supplementation doses on milk and blood thiamine status biomarkers.MethodsIn this double-blind, 4-parallel arm randomized controlled dose-response trial, healthy mothers were recruited in Kampong Thom, Cambodia. At 2 wk postpartum, women were randomly assigned to consume 1 capsule, containing 0, 1.2 (estimated average requirement), 2.4, or 10 mg of thiamine daily from 2 through 24 weeks postpartum. Human milk total thiamine concentrations were measured using HPLC. An Emax curve was plotted, which was estimated using a nonlinear least squares model in an intention-to-treat analysis. Linear mixed-effects models were used to test for differences between treatment groups. Maternal and infant blood thiamine biomarkers were also assessed.ResultsIn total, each of 335 women was randomly assigned to1 of the following thiamine-dose groups: placebo (n=83), 1.2 mg (n=86), 2.4 mg (n=81), and 10 mg (n=85). The estimated dose required to reach 90% of the maximum average total thiamine concentration in human milk (191 µg/L) is 2.35 (95% CI: 0.58, 7.01) mg/d. The mean±SD milk thiamine concentrations were significantly higher in all intervention groups (183±91, 190±105, and 206±89 µg/L for 1.2, 2.4, and 10 mg, respectively) compared with the placebo group (153±85 µg/L; P&nbsp

Objective: Polyunsaturated fatty acid (PUFA) supplements have been trialled as a treatment for a number of conditions and produced a variety of results. This variety is ascribed to the supplements, that often comprise a mixture of fatty acids, and to different effects in different organs. In this study, we tested the hypothesis that the supplementation of individual PUFAs has system-level effects that are dependent on the molecular structure of the PUFA.Methods: We undertook a network analysis using Lipid Traffic Analysis to identify both local and system-level changes in lipid metabolism using publicly available lipidomics data from a mouse model of supplementation with FA(20:4n-6), FA(20:5n-3), and FA(22:6n-3); arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid, respectively. Lipid Traffic Analysis is a new computational/bioinformatics tool that uses the spatial distribution of lipids to pinpoint changes or differences in control of metabolism, thereby suggesting mechanistic reasons for differences in observed lipid metabolism.Results: There was strong evidence for changes to lipid metabolism driven by and dependent on the structure of the supplemented PUFA. Phosphatidylcholine and triglycerides showed a change in the variety more than the total number of variables, whereas phosphatidylethanolamine and phosphatidylinositol showed considerable change in both which variables and the number of them, in a highly PUFA-dependent manner. There was also evidence for changes to the endogenous biosynthesis of fatty acids and to both the elongation and desaturation of fatty acids.Conclusions: These results show that the full biological impact of PUFA supplementation is far wider than any single-organ effect and implies that supplementation and dosing with PUFAs require a system-level assessment.(c) 2022 The Author(s). Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Advances in single cell genomics and transcriptomics have shown that at tissue level there is complex cellular heterogeneity. To understand the effect of this inter-cell heterogeneity on metabolism it is essential to develop a single cell lipid profiling approach that allows the measurement of lipids in large numbers of single cells from a population. This will provide a functional read out of cell activity and membrane structure. Using liquid extraction surface analysis (LESA) coupled with high-resolution mass spectrometry we have developed a new high-throughput method for untargeted single cell lipid profiling. This technological advance revealed new insights into the importance of cellular heterogeneity in the functional metabolism of individual human dopamine neurons, suggesting that A53T alpha-synuclein ( SNCA ) mutant neurons have impaired membrane function. These results demonstrate that this novel single cell lipid profiling platform can provide robust data that will open new frontiers in biomedical research.

© 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)., Anti-obesity drugs in the amphetamine (AMPH) class act in the brain to reduce appetite and increase locomotion. They are also characterized by adverse cardiovascular effects with origin that, despite absence of any in vivo evidence, is attributed to a direct sympathomimetic action in the heart. Here, we show that the cardiac side effects of AMPH originate from the brain and can be circumvented by PEGylation (PEGyAMPH) to exclude its central action. PEGyAMPH does not enter the brain and facilitates SNS activity via theβ2-adrenoceptor, protecting mice against obesity by increasing lipolysis and thermogenesis, coupled to higher heat dissipation, which acts as an energy sink to increase energy expenditure without altering food intake or locomotor activity. Thus, we provide proof-of-principle for a novel class of exclusively peripheral anti-obesity sympathofacilitators that are devoid of any cardiovascular and brain-related side effects., This work was supported by the Fundação Para a Ciência e Tecnologia (FCT - PTDC-BIM-MET-3750-2014 and LISBOA-01-0145-FEDER-030892), the European Molecular Biology Organization (EMBO - Installation Grant 3037), the Human Frontier Science Program (HFSP - RGY0070/2016), Maratona da Saúde (Diabetes - 2016), the European Research Council (ERC-2017-COG-771431), and the Howard Hughes Medical Institute/Wellcome International research scholar award (HHMI - 208576/Z/17/Z). G.J.L.B. is a Royal Society university Research Fellow (URF\R\180019) and FCT Investigator (IF/00624/2015). B.J. and A.K. were supported by the BBSRC (BB/M027252/1/bbsrc). We also acknowledge the Portuguese Mass Spectrometry Network (LISBOA-01-0145-FEDER-022125), the Project EU_FT-ICR_MS, funded by the European Union Horizon 2020 research and innovation program under grant agreement no. 731077. The contribution of Y.S., M.O., and F.C. was supported by Ministerio de Ciencia, Innovación y Universidades (grants AGL2017-88801-P and RTI2018-099592-B-C21). The contribution of M.L. was supported by the Xunta de Galicia (2015-CP079 and 2016-PG068), the Ministerio de Economía y Competitividad (MINECO) co-funded by the FEDER Program of EU (RTI2018-101840-B-I00 and BFU2015-70454-REDT/Adipoplast), the Atresmedia Corporación and the “la Caixa” Foundation (ID 100010434), under agreement LCF/PR/HR19/52160022. I.M. (PD/BD/52437/2013), A.B. (SFRH/BPD/96794/2013), P.M.S.D.C. (SFRH/BPD/103172/2014) and S.H.V. (SFRH/BPD/81627/2011) were supported by FCT; N.M.S. (ED481B 2016/168-0) was supported by Xunta de Galicia; and E.R.P. (BES-2015-072743) was supported by Ministerio de Economía y Competitividad (MINECO).

Fungal endophytes belonging to the genus Epichloë form associations with temperate grasses belonging to the sub-family Poöideae that range from mutualistic through to pathogenic. We previously identified a novel endophyte gene (designated gigA for grass induced gene) that is one of the most abundantly expressed fungal transcripts in endophyte-infected grasses and which is distributed and highly expressed in a wide range of Epichloë grass associations. Molecular and biochemical analyses indicate that gigA encodes a small secreted protein containing an imperfect 27 amino acid repeat that includes a kexin protease cleavage site. Kexin processing of GigA liberates within the plant multiple related products, named here as epichloëcyclins, which we have demonstrated by MS/MS to be cyclic peptidic in nature. Gene deletion of gigA leads to the elimination of all epichloëcyclins with no conspicuous phenotypic impact on the host grass, suggesting a possible bioactive role. This is a further example of a ribosomal peptide synthetic (RiPS) pathway operating within the Ascomycetes, and is the first description of such a pathway from a mutualistic symbiotic fungus from this Phylum.

One understudied function of white adipose tissue (AT) is its role in postprandial lipid buffering. In this study, we demonstrate that mice lacking the AT-specific transcription factor peroxisome proliferator activated receptor γ2 (PPARγ2) exhibit a defect in AT lipid storage rate. Impaired AT storage rate reduces metabolic flexibility, but does not compromise fasted glucose tolerance or insulin sensitivity, even after prolonged high-fat feeding. Mice eat many small meals throughout the day, limiting demands on AT storage rare. To challenge AT storage rate, we developed an acute overfeeding protocol. Overfeeding PPARγ2 KO mice caused a 10-fold increase in insulin and doubled FFA levels compared to controls. We next studied the long-term consequences of impaired AT storage rate and metabolic flexibility and showed that one year old PPARγ2 KO mice exhibited skeletal muscle insulin resistance. Our data suggest that failed AT storage may occur prior to defects in glucose handling and that overfeeding protocols may uncover genes controlling AT storage rate as opposed to capacity. Finally, our results suggest a hypercaloric mixed meal test may allow early diagnosis of humans with AT storage defects and diets that reduce demands on AT storage rate may be clinically beneficial for such individuals.

White adipose tissue (WAT) inflammation causes insulin resistance in obesity. While the role of adipose tissue macrophage (ATM) pro-inflammatory signalling in the development of insulin resistance has been established, it is less clear how WAT inflammation is initiated. Here, we show that ATMs isolated from obese mice and humans exhibit markers of increased rate of de novo phosphatidylcholine (PC) biosynthesis. Macrophage-specific knockout of phosphocholine cytidylyltransferase A (CCTα), the rate-limiting enzyme of de novo PC biosynthesis pathway, alleviated obesity-induced WAT inflammation and systemic insulin resistance. Mechanistically, CCTα-deficient macrophages showed reduced ER stress and inflammation in response to palmitate. Unlike previously suggested, this was not due to lower palmitate incorporation into cellular PCs. Instead, CCTα-null macrophages had lower membrane PC turnover, leading to elevated membrane polyunsaturated fatty acid levels that negated the pro-inflammatory effects of palmitate. Our results reveal a causal link between obesity-associated increase in de novo PC synthesis and pro-inflammatory activation of ATMs.

The complex aetiology of type 2 diabetes makes effective screening, diagnosis and prognosis a substantial challenge for the physician. The rapidly developing area of metabolomics, which uses analytical techniques such as mass spectrometry and nuclear magnetic resonance, has emerged as a promising approach to identify biomarkers of diabetes and the insulin-resistant state that precedes overt pathology. Initial successes with metabolomic studies have indicated potential biomarkers for insulin resistance and for identifying people at risk of developing diabetes, with particular focus on aminoacids and lipid metabolism. These biomarkers will help to improve research and management of diabetes. In particular, several biomarkers identified could be used for early identification of diabetes risk. Furthermore, changes in selected biomarkers can indicate effectiveness of therapeutic interventions for type 2 diabetes and the metabolic syndrome. Indeed, there is much promise that branched-chain aminoacids might provide a screening biomarker for type 2 diabetes risk, allowing early dietary and exercise interventions to treat or even prevent the disease.

Graphical abstract Epichloënin A (1) has been isolated from fungal cultures together with a minor variant epichloënin B, and ferriepichloënin A and a related peptide epichloëamide have been found in endophyte-infected plants. Highlights ► Epichloënin A has been characterized as a ferrichrome octapeptide by HRMSn and NMR. ► The minor heptapeptide variant epichloënin B has been characterized by HRMSn. ► Ferriepichloënin A was detected in guttation fluid of endophyte-infected plants. ► The related peptide epichloëamide was also detected in guttation fluid. ► Epichloëamide has been characterized as an octapeptide by HRMSn., A number of genes encoding non-ribosomal peptide synthetases (NRPSs) have been identified in fungi of Epichloë/Neotyphodium species, endophytes of Pooid grasses, including sidN, putatively encoding a ferrichrome siderophore-synthesizing NRPS. Targeted gene replacement and complementation of sidN in Epichloë festucae has established that extracellular siderophore epichloënin A is the major product of the SidN enzyme complex (Johnson et al., 2007a). We report here high resolution mass spectrometric fragmentation experiments and NMR analysis of an isolated fraction establishing that epichloënin A is a siderophore of the ferrichrome family, comprising a cyclic sequence of four glycines, a glutamine and three Nδ-trans-anhydromevalonyl–Nδ-hydroxyornithine (AMHO) moieties. Epichloënin A is unusual among ferrichrome siderophores in comprising an octapeptide rather than hexapeptide sequence, and in incorporating a glutamine residue. During this investigation we have established that desferrichrome siderophores with pendant trans-AMHO groups can be distinguished from those with pendant cis-AMHO groups by the characteristic neutral loss of an hydroxyornithine moiety in the MS/MS spectrum. A minor component, epichloënin B, has been characterized as the triglycine variant by mass spectrometry. A peptide characterized by mass spectrometry as the putative deoxygenation product, epichloëamide has been detected together with ferriepichloënin A in guttation fluid from ryegrass (Lolium perenne) plants infected with wild-type E. festucae, but not in plants infected with the ΔsidN mutant strain, and also detected at trace levels in wild-type E. festucae fungal culture.

Nonribosomal peptide synthetases (NRPSs) are large, multidomain proteins that are involved in the biosynthesis of an array of secondary metabolites. We report the structure of the third adenylation domain from the siderophore-synthesizing NRPS, SidN, from the endophytic fungus Neotyphodium lolii. This is the first structure of a eukaryotic NRPS domain, and it reveals a large binding pocket required to accommodate the unusual amino acid substrate, N(delta)-cis-anhydromevalonyl-N(delta)-hydroxy-L-ornithine (cis-AMHO). The specific activation of cis-AMHO was confirmed biochemically, and an AMHO moiety was unambiguously identified as a component of the fungal siderophore using mass spectroscopy. The protein structure shows that the substrate binding pocket is defined by 17 amino acid residues, in contrast to both prokaryotic adenylation domains and to previous predictions based on modeling. Existing substrate prediction methods for NRPS adenylation domains fail for domains from eukaryotes due to the divergence of their signature sequences from those of prokaryotes. Thus, this new structure will provide a basis for improving prediction methods for eukaryotic NRPS enzymes that play important and diverse roles in the biology of fungi.

Based on direct infusion mass spectrometry we identified a novel alkaloid as a major component of perennial ryegrass (Lolium perenne). Initial mass spectral data suggested it to be a pyrrolizidine conjugate. As this class of alkaloids has not been described before from grasses, we isolated it to elucidate its structure. The isolated alkaloid proved to be a mixture of two stereoisomers. The structures of the two compounds as determined by 1D and 2D NMR spectroscopy, were E-thesinine-O-4′-α-rhamnoside (1) and Z-thesinine-O-4′-α-rhamnoside (2). These identifications were supported by the characterisation by GC-MS and optical rotation of (+)-isoretronecanol as the necine base released on alkaline hydrolysis of these alkaloids. 1 and 2 together with the aglycone and a hexoside were also detected in tall fescue (Festuca arundinacea). This is the first report of pyrrolizidine alkaloids produced by grasses (Poaceae).

Indole diterpenes are a large, structurally and functionally diverse group of secondary metabolites produced by filamentous fungi. Biosynthetic schemes have been proposed for these metabolites but until recently none of the proposed steps had been validated by biochemical or genetic studies. Using Penicillium paxilli as a model experimental system to study indole diterpene biosynthesis we previously showed by deletion analysis that a cluster of seven genes is required for paxilline biosynthesis. Two of these pax genes, paxP and paxQ (encoding cytochrome P450 monooxygenases), are required in the later steps in this pathway. Here, we describe the function of paxP and paxQ gene products by feeding proposed paxilline intermediates to strains lacking the pax cluster but containing ectopically integrated copies of paxP or paxQ. Transformants containing paxP converted paspaline into 13-desoxypaxilline as the major product and β-PC-M6 as the minor product. β-PC-M6, but not α-PC-M6, was also a substrate for PaxP and was converted to 13-desoxypaxilline. paxQ-containing transformants converted 13-desoxypaxilline into paxilline. These results confirm that paspaline, β-PC-M6, and 13-desoxypaxilline are paxilline intermediates and that paspaline and β-PC-M6 are substrates for PaxP, and 13-desoxypaxilline is a substrate for PaxQ. PaxP and PaxQ also utilized β-paxitriol and α-PC-M6 as substrates converting them to paxilline and α-paxitriol, respectively. These findings have allowed us to delineate clearly the biosynthetic pathway for paxilline for the first time.

Combinatorial biosynthesis is a new tool in the generation of novel natural products and for the production of rare and expensive natural products. The basic concept is combining metabolic pathways in different organisms on a genetic level. As a consequence heterologous organisms provide precursors from their own primary and secondary metabolism that are metabolised to the desired secondary product due to the expression of foreign genes. In this review we discuss the possibilities and limitations of combining genes from different organisms and the expression of heterologous genes. Major focuses are fundamentals of the genetic work, used expression systems and latest progress in this field. Combinatorial biosynthesis is discussed for important classes of natural products, including alkaloids (vinblastine, vincristine), terpenoids (artemisinin, paclitaxel) and flavonoids. The role and importance of today's used host organisms is critically described, and the latest approaches discussed to give an outlook for future trends and possibilities. (c) 2006 Elsevier B.V. All rights reserved.

Biotransformation of deoxypodophyllotoxin to epipodophyllotoxin by three major human hepatic enzymes, CYP1A2, CYP2C9 and CYP3A4, heterologously expressed in E coli DH5 alpha, was investigated. It was shown that CYP3A4 catalysed the hydroxylation of deoxypodophyllotoxin into epipodophyllotoxin in yields up to 90%. The structure of the metabolite was determined using HPLC-MS and HPLC-SPE-NMR. techniques. There was no detectable production of epipodophyllotoxin or podophyllotoxin by CYP1A2 and CYP2C9 enzymes. The CYP3A4 enzyme shows a distinctly different reactivity to deoxypodophyllotoxin compared to the semi-synthetic derivatives etoposide and teniposide, which are degraded by 3-O-demethylation. These findings demonstrate a novel system for the production of 2,7'-cyclolignans, starting from the easily accessible deoxypodophyllotoxin. (c) 2006 Elsevier B.V. All rights reserved.

Six ascidian species from the Dutch North Sea coast were screened for cytotoxic activity, Freeze-dried biological material was extracted with solvents of different polarity followed by determination of the cytotoxicity. The most active extracts were further separated using different chromatographic techniques. The microculture tetrazolium (MTT) assay was used to determine the cytotoxicity against two human tumor cell lines: COLO320 (a colon adenocarcinoma) and GLC(4) (a small cell lung carcinoma). The two cell lines were selected for their different response towards known cytostatics. GLC(4) is sensitive and COLO320 is resistant to most of the known cytostatics. Three of the species tested yielded interesting fractions. From the in colonial Didemnum lahillei we have isolated a compound which is more active against the COLO320 cell line (IC50:33 mu g ml(-1)) than the GLC(4) (IC50:49 mu g ml(-1)). The structure is currently elucidated. Another colonial species, Aplidium glabrum, yielded a very cytotoxic fraction, with an IC,, of 5 mu g ml(-1) against the COLO320 cell line. From our results it can be concluded that the North Sea could be another interesting source of new compounds with pharmaceutical potential. (C) 1999 Elsevier Science B.V. All tights reserved.