Physiologically relevant culture medium Plasmax improves human placental trophoblast stem cell function

Human trophoblast cultures provide powerful tools to model key processes of placental development. In vitro trophoblast studies to date have relied on commercial media which contains non-physiological levels of nutrients, and the impact of these conditions on trophoblast metabolism and function is unknown. Here we show that the physiological medium (Plasmaxä) with nutrient and metabolite concentrations recapitulating human plasma improves human trophoblast stem cell (hTSC) proliferation and differentiation compared to standard medium (DMEM-F12). hTSCs cultured in Plasmax-based medium also show altered glycolytic and mitochondrial metabolism, as well as reduced S-adenosylmethionine/S-adenosyl-homosysteine ratio compared to DMEM-F12-based medium. These findings demonstrate the importance of the nutritional environment for phenotyping cultured human trophoblasts

Comparative analysis of MTP -493G/T and ABCG2 34G/A polymorphisms and theirs expression in HIV-associated lipodystrophy patients

HIV-associated lipodystrophy (HIVLD) is a metabolic condition with an irregularity in the production of lipoprotein particles, and its occurrence varies among HIV-infected patients. MTP and ABCG2 genes have a role in the transport of lipoproteins. The polymorphisms of MTP -493G/T and ABCG2 34G/A affect its expression and influence the secretion and transportation of lipoproteins. Hence, we investigated the MTP -493G/T and ABCG2 34G/A polymorphisms in 187 HIV-infected patients (64 with HIVLD and 123 without HIVLD) along with 139 healthy controls using polymerase chain reaction (PCR)-restriction fragment length polymorphism and expression analysis using real-time PCR. ABCG2 34A allele showed an insignificantly reduced risk of LDHIV severity [P = 0.07, odds ratio (OR) = 0.55]. MTP -493T allele exhibited a non-significantly reduced risk for the development of dyslipidemia (P = 0.08, OR = 0.71). In patients with HIVLD, the ABCG2 34GA genotype was linked with impaired low-density lipoprotein levels and showed a reduced risk for LDHIV severity (P = 0.04, OR = 0.17). In patients without HIVLD, the ABCG2 34GA genotype was associated with impaired triglyceride levels with marginal significance and showed an increased risk for the development of dyslipidemia (P = 0.07, OR = 2.76). The expression level of MTP gene was 1.22-fold decreased in patients without HIVLD compared with that in patients with HIVLD. ABCG2 gene was upregulated 2.16-fold in patients with HIVLD than in patients without HIVLD. In conclusion, MTP -493C/T polymorphism influences the expression level of MTP in patients without HIVLD. Individuals without HIVLD having ABCG2 34GA genotype with impaired triglyceride levels may facilitate dyslipidemia risk

Hepatic glutamine synthetase controls N5-methylglutamine in homeostasis and cancer

Glutamine synthetase (GS) activity is conserved from prokaryotes to humans, where the ATP-dependent production of glutamine from glutamate and ammonia is essential for neurotransmission and ammonia detoxification. Here, we show that mammalian GS uses glutamate and methylamine to produce a methylated glutamine analog, N5-methylglutamine. Untargeted metabolomics revealed that liver-specific GS deletion and its pharmacological inhibition in mice suppress hepatic and circulating levels of N5-methylglutamine. This alternative activity of GS was confirmed in human recombinant enzyme and cells, where a pathogenic mutation in the active site (R324C) promoted the synthesis of N5-methylglutamine over glutamine. N5-Methylglutamine is detected in the circulation, and its levels are sustained by the microbiome, as demonstrated by using germ-free mice. Finally, we show that urine levels of N5-methylglutamine correlate with tumor burden and GS expression in a β-catenin-driven model of liver cancer, highlighting the translational potential of this uncharacterized metabolite

Physiologically relevant culture medium Plasmax improves human placental trophoblast stem cell function.

Human trophoblast cultures provide powerful tools to model key processes of placental development. In vitro trophoblast studies to date have relied on commercial media which contains non-physiological levels of nutrients, and the impact of these conditions on trophoblast metabolism and function is unknown. Here we show that the physiological medium (Plasmaxä) with nutrient and metabolite concentrations recapitulating human plasma improves human trophoblast stem cell (hTSC) proliferation and differentiation compared to standard medium (DMEM-F12). hTSCs cultured in Plasmax-based medium also show altered glycolytic and mitochondrial metabolism, as well as reduced S-adenosylmethionine/S-adenosyl-homosysteine ratio compared to DMEM-F12-based medium. These findings demonstrate the importance of the nutritional environment for phenotyping cultured human trophoblasts

Mesenchymal stromal cells cultured in physiological conditions sustain citrate secretion with glutamate anaplerosis

Bone marrow mesenchymal stromal cells (MSCs) have immunomodulatory and regenerative potential. However, culture conditions govern their metabolic processes and therapeutic efficacy. Here we show that culturing donor-derived MSCs in Plasmax™, a physiological medium with the concentrations of nutrients found in human plasma, supports their proliferation and stemness, and prevents the nutritional stress induced by the conventional medium DMEM. The quantification of the exchange rates of metabolites between cells and medium, untargeted metabolomics, stable isotope tracing and transcriptomic analysis, performed at physiologically relevant oxygen concentrations (1%O2), reveal that MSCs rely on a high rate of glucose to lactate conversion, coupled with parallel anaplerotic fluxes from glutamine and glutamate to support citrate synthesis and secretion. These distinctive traits of MSCs shape the metabolic microenvironment of the bone marrow niche and can influence nutrient cross-talks under physiological and pathological conditions

An IDH1-vitamin C crosstalk drives human erythroid development by inhibiting pro-oxidant mitochondrial metabolism

International audienceHighlights d Glutamine-dependent OXPHOS drives early erythroid differentiation d OXPHOS-induced ROS inhibit erythroblast enucleation d IDH1 downregulation augments ROS, leading to pathological erythroid differentiation d Vitamin C rescues erythroid differentiation under conditions of oxidative stres