Immunometabolic adaptation in monocytes underpins functional changes during pregnancy.

Metabolic heterogeneity is a determinant of immune cell function. The normal physiological metabolic reprogramming of pregnancy that ensures the fuel requirements of mother and baby are met, might also underpin changes in immunity that occur with pregnancy and manifest as altered responses to pathogens and changes to autoimmune disease symptoms. Using peripheral blood from pregnant women at term, we reveal that monocytes lose M2-like and gain M1-like properties accompanied by reductions in mitochondrial mass, maximal respiration, and cardiolipin content in pregnancy; glycolysis is unperturbed. We establish that muramyl dipeptide (MDP)-stimulated cytokine production relies on oxidative metabolism, then show in pregnancy reduced cytokine production in response to MDP but not LPS. Overall, mitochondrially centered metabolic capabilities of late gestation monocytes are down-regulated revealing natural plasticity in monocyte phenotype and function that could reveal targets for improving pregnancy outcomes but also yield alternative therapeutic approaches to diverse metabolic and/or immune-mediated diseases beyond pregnancy.

Mutualism on the edge: Understanding the Paramecium-Chlorella symbiosis.

Exploring the mechanisms that underpin symbiosis requires an understanding of how these complex interactions are maintained in diverse model systems. The ciliate protist, Paramecium bursaria, offers a valuable insight into how emergent endosymbiotic interactions have evolved.

Iron Is Critical for Mucosal-Associated Invariant T Cell Metabolism and Effector Functions.

Mucosal-Associated Invariant T (MAIT) cells are a population of innate T cells that play a critical role in host protection against bacterial and viral pathogens. Upon activation, MAIT cells can rapidly respond via both TCR-dependent and -independent mechanisms, resulting in robust cytokine production. The metabolic and nutritional requirements for optimal MAIT cell effector responses are still emerging. Iron is an important micronutrient and is essential for cellular fitness, in particular cellular metabolism. Iron is also critical for many pathogenic microbes, including those that activate MAIT cells. However, iron has not been investigated with respect to MAIT cell metabolic or functional responses. In this study, we show that human MAIT cells require exogenous iron, transported via CD71 for optimal metabolic activity in MAIT cells, including their production of ATP. We demonstrate that restricting iron availability by either chelating environmental iron or blocking CD71 on MAIT cells results in impaired cytokine production and proliferation. These data collectively highlight the importance of a CD71-iron axis for human MAIT cell metabolism and functionality, an axis that may have implications in conditions where iron availability is limited.

Multi-omics and imaging mass cytometry characterization of human kidneys to identify pathways and phenotypes associated with impaired kidney function.

Despite the recent advances in our understanding of the role of lipids, metabolites, and related enzymes in mediating kidney injury, there is limited integrated multi-omics data identifying potential metabolic pathways driving impaired kidney function. The limited availability of kidney biopsies from living donors with acute kidney injury has remained a major constraint. Here, we validated the use of deceased transplant donor kidneys as a good model to study acute kidney injury in humans and characterized these kidneys using imaging and multi-omics approaches. We noted consistent changes in kidney injury and inflammatory markers in donors with reduced kidney function. Neighborhood and correlation analyses of imaging mass cytometry data showed that subsets of kidney cells (proximal tubular cells and fibroblasts) are associated with the expression profile of kidney immune cells, potentially linking these cells to kidney inflammation. Integrated transcriptomic and metabolomic analysis of human kidneys showed that kidney arachidonic acid metabolism and seven other metabolic pathways were upregulated following diminished kidney function. To validate the arachidonic acid pathway in impaired kidney function we demonstrated increased levels of cytosolic phospholipase A2 protein and related lipid mediators (prostaglandin E2) in the injured kidneys. Further, inhibition of cytosolic phospholipase A2 reduced injury and inflammation in human kidney proximal tubular epithelial cells in vitro. Thus, our study identified cell types and metabolic pathways that may be critical for controlling inflammation associated with impaired kidney function in humans.

Differentiation signals induce APOBEC3A expression via GRHL3 in squamous epithelia and squamous cell carcinoma.

Two APOBEC (apolipoprotein-B mRNA editing enzyme catalytic polypeptide-like) DNA cytosine deaminase enzymes (APOBEC3A and APOBEC3B) generate somatic mutations in cancer, driving tumour development and drug resistance. Here we used single cell RNA sequencing to study APOBEC3A and APOBEC3B expression in healthy and malignant mucosal epithelia, validating key observations with immunohistochemistry, spatial transcriptomics and functional experiments. Whereas APOBEC3B is expressed in keratinocytes entering mitosis, we show that APOBEC3A expression is confined largely to terminally differentiating cells and requires Grainyhead-like transcription factor 3 (GRHL3). Thus, in normal tissue, neither deaminase appears to be expressed at high levels during DNA replication, the cell cycle stage associated with APOBEC-mediated mutagenesis. In contrast, we show that in squamous cell carcinoma tissues, there is expansion of GRHL3 expression and activity to a subset of cells undergoing DNA replication and concomitant extension of APOBEC3A expression to proliferating cells. These findings indicate a mechanism for acquisition of APOBEC3A mutagenic activity in tumours.

Lipidomic signatures discriminate subtle hepatic changes in the progression of porcine nonalcoholic steatohepatitis.

Recently, the development of nonalcoholic steatohepatitis (NASH) in common strains of pigs has been achieved using a diet high in saturated fat, fructose, cholesterol, and cholate and deficient in choline and methionine. The aim of the present work was to characterize the hepatic and plasma lipidomic changes that accompany the progression of NASH and its reversal by switching pigs back to a chow diet. One month of this extreme steatotic diet was sufficient to induce porcine NASH. The lipidomic platform using liquid chromatography-mass spectrometry analyzed 467 lipid species. Seven hepatic phospholipids [PC(30:0), PC(32:0), PC(33:0), PC(33:1), PC(34:0), PC(34:3) and PC(36:2)] significantly discriminated the time of dietary exposure, and PC(30:0), PC(33:0), PC(33:1) and PC(34:0) showed rapid adaptation in the reversion period. Three transcripts (CS, MAT1A, and SPP1) showed significant changes associated with hepatic triglycerides and PC(33:0). Plasma lipidomics revealed that these species [FA 16:0, FA 18:0, LPC(17:1), PA(40:5), PC(37:1), TG(45:0), TG(47:2) and TG(51:0)] were able to discriminate the time of dietary exposure. Among them, FA 16:0, FA 18:0, LPC(17:1) and PA(40:5) changed the trend in the reversion phase. Plasma LDL-cholesterol and IL12P40 were good parameters to study the progression of NASH, but their capacity was surpassed by hepatic [PC(33:0), PC(33:1), and PC(34:0)] or plasma lipid [FA 16:0, FA 18:0, and LPC(17:1)] species. Taken together, these lipid species can be used as biomarkers of metabolic changes in the progression and regression of NASH in this model. The lipid changes suggest that the development of NASH also affects peripheral lipid metabolism.NEW & NOTEWORTHY A NASH stage was obtained in crossbred pigs. Hepatic [PC(33:0), PC(33:1) and PC(34:0)] or plasma [FA 16:0, FA 18:0 and LPC(17:1)] species were sensitive parameters to detect subtle changes in development and regression of nonalcoholic steatohepatitis (NASH). These findings may delineate the liquid biopsy to detect subtle changes in progression or in treatments. Furthermore, phospholipid changes according to the insult-inducing NASH may play an important role in accepting or rejecting fatty livers in transplantation.

Loss of mitochondrial pyruvate carrier 1 supports proline-dependent proliferation and collagen biosynthesis in ovarian cancer.

The pyruvate transporter MPC1 (mitochondrial pyruvate carrier 1) acts as a tumour-suppressor, loss of which correlates with a pro-tumorigenic phenotype and poor survival in several tumour types. In high-grade serous ovarian cancers (HGSOC), patients display copy number loss of MPC1 in around 78% of cases and reduced MPC1 mRNA expression. To explore the metabolic effect of reduced expression, we demonstrate that depleting MPC1 in HGSOC cell lines drives expression of key proline biosynthetic genes; PYCR1, PYCR2 and PYCR3, and biosynthesis of proline. We show that altered proline metabolism underpins cancer cell proliferation, reactive oxygen species (ROS) production, and type I and type VI collagen formation in ovarian cancer cells. Furthermore, exploring The Cancer Genome Atlas, we discovered the PYCR3 isozyme to be highly expressed in a third of HGSOC patients, which was associated with more aggressive disease and diagnosis at a younger age. Taken together, our study highlights that targeting proline metabolism is a potential therapeutic avenue for the treatment of HGSOC.

Definitions and measures of long COVID fatigue in adults: a scoping review protocol.

OBJECTIVE: The aim of this scoping review is to investigate how fatigue is defined and measured in adults with long COVID. INTRODUCTION: Following COVID-19 infection, 10% to 20% of individuals experience persisting symptoms for a minimum of 3 months; this is commonly known as long COVID. Fatigue is one of the most prevalent symptoms of long COVID, but there is currently no consistently applied definition of long COVID fatigue. To advance our understanding of long COVID fatigue, we must first identify the current definitions and measures being used to describe and mesure this condition. INCLUSION CRITERIA: This review will consider published and unpublished studies involving adults (≥18 years) that define and/or measure long COVID fatigue. Papers using quantitative or qualitative designs will be included. Conference abstracts, editorials, and opinion papers will be excluded. METHODS: Published studies from January 2020 onwards will be searched for across MEDLINE (Ovid), CINAHL (EBSCOhost), Embase (Ovid), Scopus, PsycINFO (Ovid), Web of Science Core Collection, Epistemonikos, and Cochrane Central Register of Controlled Trials (CENTRAL). Dimensions, Overton, and ProQuest Dissertations and Theses will be searched for unpublished literature. Eligible records will be de-duplicated, and 2 independent reviewers will carry out title, abstract, and full-text screening. A data extraction tool will be pilot tested on a small number of papers, then modified as necessary, with any modifications detailed in the scoping review. Findings will be presented in tables and charts, supported by a narrative summary. REVIEW REGISTRATION: Open Science Framework https://osf.io/hnf8z.

Identification of a non-canonical ciliate nuclear genetic code where UAA and UAG code for different amino acids.

The genetic code is one of the most highly conserved features across life. Only a few lineages have deviated from the "universal" genetic code. Amongst the few variants of the genetic code reported to date, the codons UAA and UAG virtually always have the same translation, suggesting that their evolution is coupled. Here, we report the genome and transcriptome sequencing of a novel uncultured ciliate, belonging to the Oligohymenophorea class, where the translation of the UAA and UAG stop codons have changed to specify different amino acids. Genomic and transcriptomic analyses revealed that UAA has been reassigned to encode lysine, while UAG has been reassigned to encode glutamic acid. We identified multiple suppressor tRNA genes with anticodons complementary to the reassigned codons. We show that the retained UGA stop codon is enriched in the 3'UTR immediately downstream of the coding region of genes, suggesting that there is functional drive to maintain tandem stop codons. Using a phylogenomics approach, we reconstructed the ciliate phylogeny and mapped genetic code changes, highlighting the remarkable number of independent genetic code changes within the Ciliophora group of protists. According to our knowledge, this is the first report of a genetic code variant where UAA and UAG encode different amino acids.

The metabolic response of human trophoblasts derived from term placentas to metformin.

AIMS/HYPOTHESIS: Metformin is increasingly used therapeutically during pregnancy worldwide, particularly in the treatment of gestational diabetes, which affects a substantial proportion of pregnant women globally. However, the impact on placental metabolism remains unclear. In view of the association between metformin use in pregnancy and decreased birthweight, it is essential to understand how metformin modulates the bioenergetic and anabolic functions of the placenta. METHODS: A cohort of 55 placentas delivered by elective Caesarean section at term was collected from consenting participants. Trophoblasts were isolated from the placental samples and treated in vitro with clinically relevant doses of metformin (0.01 mmol/l or 0.1 mmol/l) or vehicle. Respiratory function was assayed using high-resolution respirometry to measure oxygen concentration and calculated [Formula: see text]. Glycolytic rate and glycolytic stress assays were performed using Agilent Seahorse XF assays. Fatty acid uptake and oxidation measurements were conducted using radioisotope-labelled assays. Lipidomic analysis was conducted using LC-MS. Gene expression and protein analysis were performed using RT-PCR and western blotting, respectively. RESULTS: Complex I-supported oxidative phosphorylation was lower in metformin-treated trophoblasts (0.01 mmol/l metformin, 61.7% of control, p<0.05; 0.1 mmol/l metformin, 43.1% of control, p<0.001). The proton efflux rate arising from glycolysis under physiological conditions was increased following metformin treatment, up to 23±5% above control conditions following treatment with 0.1 mmol/l metformin (p<0.01). There was a significant increase in triglyceride concentrations in trophoblasts treated with 0.1 mmol/l metformin (p<0.05), particularly those of esters of long-chain polyunsaturated fatty acids. Fatty acid oxidation was reduced by ~50% in trophoblasts treated with 0.1 mmol/l metformin compared with controls (p<0.001), with no difference in uptake between treatment groups. CONCLUSIONS/INTERPRETATION: In primary trophoblasts derived from term placentas metformin treatment caused a reduction in oxidative phosphorylation through partial inactivation of complex I and potentially by other mechanisms. Metformin-treated trophoblasts accumulate lipids, particularly long- and very-long-chain polyunsaturated fatty acids. Our findings raise clinically important questions about the balance of risk of metformin use during pregnancy, particularly in situations where the benefits are not clear-cut and alternative therapies are available.

Aetiology of Type 2 diabetes in people with a 'normal' body mass index: testing the personal fat threshold hypothesis.

Weight loss in overweight or obese individuals with Type 2 diabetes (T2D) can normalize hepatic fat metabolism, decrease fatty acid oversupply to ß cells and restore normoglycaemia. One in six people has BMI <27 kg/m2 at diagnosis, and their T2D is assumed to have different aetiology. The Personal Fat Threshold hypothesis postulated differing individual thresholds for lipid overspill and adverse effects on ß-cell function. To test this hypothesis, people with Type 2 diabetes and body mass index <27kg/m2 (n = 20) underwent repeated 5% weight loss cycles. Metabolic assessments were carried out at stable weight after each cycle and after 12 months. To determine how closely metabolic features returned to normal, 20 matched normoglycemic controls were studied once. Between baseline and 12 months: BMI fell (mean ± SD), 24.8 ± 0.4 to 22.5 ± 0.4 kg/m2 (P<0.0001) (controls: 21.5 ± 0.5); total body fat, 32.1 ± 1.5 to 27.6 ± 1.8% (P<0.0001) (24.6 ± 1.5). Liver fat content and fat export fell to normal as did fasting plasma insulin. Post-meal insulin secretion increased but remained subnormal. Sustained diabetes remission (HbA1c < 48 mmol/mol off all glucose-lowering agents) was achieved by 70% (14/20) by initial weight loss of 6.5 (5.5-10.2)%. Correction of concealed excess intra-hepatic fat reduced hepatic fat export, with recovery of ß-cell function, glycaemic improvement in all and return to a non-diabetic metabolic state in the majority of this group with BMI <27 kg/m2 as previously demonstrated for overweight or obese groups. The data confirm the Personal Fat Threshold hypothesis: aetiology of Type 2 diabetes does not depend on BMI. This pathophysiological insight has major implications for management.

Lipidome Profiling in Childhood Obesity Compared to Adults: A Pilot Study.

The objective is to assess the circulating lipidome of children with obesity before and after lifestyle intervention and to compare the data to the circulating lipidome of adults with obesity before and after bariatric surgery. Ten pediatric (PE) and thirty adult (AD) patients with obesity were prospectively recruited at a referral single center. The PE cohort received lifestyle recommendations. The AD cohort underwent bariatric surgery. Clinical parameters and lipidome were analyzed in serum before and after six months of metabolic intervention. The abundance of phosphatidylinositols in the PE cohort and phosphatidylcholines in the AD significantly increased, while O-phosphatidylserines in the PE cohort and diacyl/triacylglycerols in the AD decreased. Fifteen lipid species were coincident in both groups after lifestyle intervention and bariatric surgery. Five species of phosphatidylinositols, sphingomyelins, and cholesteryl esters were upregulated. Eight species of diacylglycerols, glycerophosphoglycerols, glycerophosphoethanolamines, and phosphatidylcholines were downregulated. Most matching species were regulated in the same direction except for two phosphatidylinositols: PI(O-36:2) and PI(O-34:0). A specific set of lipid species regulated after bariatric surgery in adult individuals was also modulated in children undergoing lifestyle intervention, suggesting they may constitute a core circulating lipid profile signature indicative of early development of obesity and improvement after clinical interventions regardless of individual age.

Glycogen-fuelled metabolism supports rapid mucosal-associated invariant T cell responses.

Mucosal-associated invariant T (MAIT) cells are a subset of unconventional T cells which recognize a limited repertoire of ligands presented by the MHC class-I like molecule MR1. In addition to their key role in host protection against bacterial and viral pathogens, MAIT cells are emerging as potent anti-cancer effectors. With their abundance in human, unrestricted properties, and rapid effector functions MAIT cells are emerging as attractive candidates for immunotherapy. In the current study, we demonstrate that MAIT cells are potent cytotoxic cells, rapidly degranulating and inducing target cell death. Previous work from our group and others has highlighted glucose metabolism as a critical process for MAIT cell cytokine responses at 18 h. However, the metabolic processes supporting rapid MAIT cell cytotoxic responses are currently unknown. Here, we show that glucose metabolism is dispensable for both MAIT cell cytotoxicity and early (<3 h) cytokine production, as is oxidative phosphorylation. We show that MAIT cells have the machinery required to make (GYS-1) and metabolize (PYGB) glycogen and further demonstrate that that MAIT cell cytotoxicity and rapid cytokine responses are dependent on glycogen metabolism. In summary, we show that glycogen-fueled metabolism supports rapid MAIT cell effector functions (cytotoxicity and cytokine production) which may have implications for their use as an immunotherapeutic agent.

Canagliflozin impairs T cell effector function via metabolic suppression in autoimmunity.

Augmented T cell function leading to host damage in autoimmunity is supported by metabolic dysregulation, making targeting immunometabolism an attractive therapeutic avenue. Canagliflozin, a type 2 diabetes drug, is a sodium glucose co-transporter 2 (SGLT2) inhibitor with known off-target effects on glutamate dehydrogenase and complex I. However, the effects of SGLT2 inhibitors on human T cell function have not been extensively explored. Here, we show that canagliflozin-treated T cells are compromised in their ability to activate, proliferate, and initiate effector functions. Canagliflozin inhibits T cell receptor signaling, impacting on ERK and mTORC1 activity, concomitantly associated with reduced c-Myc. Compromised c-Myc levels were encapsulated by a failure to engage translational machinery resulting in impaired metabolic protein and solute carrier production among others. Importantly, canagliflozin-treated T cells derived from patients with autoimmune disorders impaired their effector function. Taken together, our work highlights a potential therapeutic avenue for repurposing canagliflozin as an intervention for T cell-mediated autoimmunity.

Non-alcoholic fatty liver disease is characterised by a reduced polyunsaturated fatty acid transport via free fatty acids and high-density lipoproteins (HDL).

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.

Dietary squalene supplementation decreases triglyceride species and modifies phospholipid lipidomic profile in the liver of a porcine model of non-alcoholic steatohepatitis.

Squalene is a key minor component of virgin olive oil, the main source of fat in the Mediterranean diet, and had shown to improve the liver metabolism in rabbits and mice. The present research was carried out to find out whether this effect was conserved in a porcine model of hepatic steatohepatitis and to search for the lipidomic changes involved. The current study revealed that a 0.5% squalene supplementation to a steatotic diet for a month led to hepatic accumulation of squalene and decreased triglyceride content as well as area of hepatic lipid droplets without influencing cholesterol content or fiber areas. However, ballooning score was increased and associated with the hepatic squalene content. Of forty hepatic transcripts related to lipid metabolism and hepatic steatosis, only citrate synthase and a non-coding RNA showed decreased expressions. The hepatic lipidome, assessed by liquid chromatography-mass spectrometry in a platform able to analyze 467 lipids, revealed that squalene supplementation increased ceramide, Cer(36:2), and phosphatidylcholine (PC[32:0], PC[33:0] and PC[34:0]) species and decreased cardiolipin, CL(69:5), and triglyceride (TG[54:2], TG[55:0] and TG[55:2]) species. Plasma levels of interleukin 12p40 increased in pigs receiving the squalene diet. The latter also modified plasma lipidome by increasing TG(58:12) and decreasing non-esterified fatty acid (FA 14:0, FA 16:1 and FA 18:0) species without changes in total NEFA levels. Together this shows that squalene-induced changes in hepatic and plasma lipidomic profiles, non-coding RNA and anti-inflammatory interleukin are suggestive of an alleviation of the disease despite the increase in the ballooning score.

A Correlative Study of Interfacial Segregation in a Cu-Doped TiNiSn Thermoelectric half-Heusler Alloy.

The performance of thermoelectric materials depends on both their atomic-scale chemistry and the nature of microstructural details such as grain boundaries and inclusions. Here, the elemental distribution throughout a TiNiCu0.1Sn thermoelectric material has been examined in a correlative study deploying atom-probe tomography (APT) and electron microscopies and spectroscopies. Elemental mapping and electron diffraction reveal two distinct types of grain boundary that are either topologically rough and meandering in profile or more regular and geometric. Transmission electron microscopy studies indicate that the Cu dopant segregates at both grain boundary types, attributed to extrusion from the bulk during hot-pressing. The geometric boundaries are found to have a degree of crystallographic coherence between neighboring grains; the rough boundaries are decorated with oxide impurity precipitates. APT was used to study the three-dimensional character of rough grain boundaries and reveals that Cu is present as discrete, elongated nanoprecipitates cosegregating alongside larger substoichiometric titanium oxide precipitates. Away from the grain boundary, the alloy microstructure is relatively homogeneous, and the atom-probe results suggest a statistical and uniform distribution of Cu with no evidence for segregation within grains. The extrusion suggests a solubility limit for Cu in the bulk material, with the potential to influence carrier and phonon transport properties across grain boundaries. These results underline the importance of fully understanding localized variations in chemistry that influence the functionality of materials, particularly at grain boundaries.

Impact of Metformin Treatment on Human Placental Energy Production and Oxidative Stress.

Metformin is increasingly prescribed in pregnancy, with beneficial maternal effects. However, it is not known how metformin-treatment impacts metabolism and energy production in the developing feto-placental unit. We assessed the human placental response to metformin using both in vivo and in vitro treated samples. trophoblasts were derived from placentas collected from non-laboured Caesarean deliveries at term, then treated in vitro with metformin (0.01 mM, 0.1 mM or vehicle). Metformin-concentrations were measured using liquid-chromatography mass-spectrometry. Oxygen consumption in cultured-trophoblasts was measured using a Seahorse-XF Mito Stress Test. Markers of oxidative-stress were assayed using qRT-PCR. Metformin-transporter mRNA and protein-levels were determined by quantitative RT-PCR and Western-blotting respectively. Metformin concentrations were also measured in sample trios (maternal plasma/fetal plasma/placental tissue) from pregnancies exposed to metformin on clinical-grounds. Maternal and fetal metformin concentrations in vivo were highly correlated over a range of concentrations (R2 = 0.76, p < 0.001; average fetal:maternal ratio 1.5; range 0.8-2.1). Basal respiration in trophoblasts was reduced by metformin treatment (0.01 mM metformin; p < 0.05, 0.1 mM metformin; p < 0.001). Mitochondrial-dependent ATP production and proton leak were reduced after treatment with metformin (p < 0.001). Oxidative stress markers were significantly reduced in primary-trophoblast-cultures following treatment with metformin. There is a close linear relationship between placental, fetal, and maternal metformin concentrations. Primary-trophoblast cultures exposed to clinically-relevant metformin concentrations have reduced mitochondrial-respiration, mitochondrial-dependent ATP-production, and reduced markers of oxidative-stress. Given the crucial role of placental energy-production in supporting fetal growth and well-being during pregnancy, the implications of these findings are concerning for intrauterine fetal growth and longer-term metabolic programming in metformin-exposed pregnancies.

Placental sex-dependent spermine synthesis regulates trophoblast gene expression through acetyl-coA metabolism and histone acetylation.

Placental function and dysfunction differ by sex but the mechanisms are unknown. Here we show that sex differences in polyamine metabolism are associated with escape from X chromosome inactivation of the gene encoding spermine synthase (SMS). Female placental trophoblasts demonstrate biallelic SMS expression, associated with increased SMS mRNA and enzyme activity. Polyamine depletion in primary trophoblasts reduced glycolysis and oxidative phosphorylation resulting in decreased acetyl-coA availability and global histone hypoacetylation in a sex-dependent manner. Chromatin-immunoprecipitation sequencing and RNA-sequencing identifies progesterone biosynthesis as a target of polyamine regulated gene expression, and polyamine depletion reduced progesterone release in male trophoblasts. The effects of polyamine depletion can be attributed to spermine as SMS-silencing recapitulated the effects on energy metabolism, histone acetylation, and progesterone release. In summary, spermine metabolism alters trophoblast gene expression through acetyl-coA biosynthesis and histone acetylation, and SMS escape from X inactivation explains some features of human placental sex differences.

Lipidomic Approaches to Study HDL Metabolism in Patients with Central Obesity Diagnosed with Metabolic Syndrome.

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors characterised by central obesity, atherogenic dyslipidaemia, and changes in the circulating lipidome; the underlying mechanisms that lead to this lipid remodelling have only been partially elucidated. This study used an integrated "omics" approach (untargeted whole serum lipidomics, targeted proteomics, and lipoprotein lipidomics) to study lipoprotein remodelling and HDL composition in subjects with central obesity diagnosed with MetS (vs. controls). Compared with healthy subjects, MetS patients showed higher free fatty acids, diglycerides, phosphatidylcholines, and triglycerides, particularly those enriched in products of de novo lipogenesis. On the other hand, the "lysophosphatidylcholines to phosphatidylcholines" and "cholesteryl ester to free cholesterol" ratios were reduced, pointing to a lower activity of lecithin cholesterol acyltransferase (LCAT) in MetS; LCAT activity (directly measured and predicted by lipidomic ratios) was positively correlated with high-density lipoprotein cholesterol (HDL-C) and negatively correlated with body mass index (BMI) and insulin resistance. Moreover, many phosphatidylcholines and sphingomyelins were significantly lower in the HDL of MetS patients and strongly correlated with BMI and clinical metabolic parameters. These results suggest that MetS is associated with an impairment of phospholipid metabolism in HDL, partially led by LCAT, and associated with obesity and underlying insulin resistance. This study proposes a candidate strategy to use integrated "omics" approaches to gain mechanistic insights into lipoprotein remodelling, thus deepening the knowledge regarding the molecular basis of the association between MetS and atherosclerosis.