Search Results (243)

Background: Tumor cells can reprogram their metabolism, constituting a hallmark of cancer that plays a crucial role in tumor progression. As tumor cells exhibit an increased demand for nutrients, e.g., amino acids, they rely on extracellular sources and show deregulation of transport proteins. Among these, SNAT1 (SLC38A1) is described as the loader for glutamine that is responsible for the main influx of this amino acid. The aim of this study was to assess the molecular function of SNAT1 in melanoma regarding its role in amino acid transport and regulation of cellular metabolism. Methods: siPool-mediated downregulation of SNAT1 expression in melanoma cell lines was used to investigate the molecular function of this protein. Glutamine transport was assessed by measuring the intracellular and extracellular concentrations of glutamine. Regulation of downstream effectors was evaluated with qRT-PCR and Western Blot. Metabolism was investigated by performing Seahorse flux analysis. Mitochondrial staining was examined via flow cytometry. Protein interaction was assessed with Co-IP, and in silico modeling of protein interaction was performed with AlphaFold3. Results: In this study, we uncovered the new finding that SNAT1 is not primarily implicated in glutamine influx into melanoma cells but in signaling in response to extracellular glutamine. We identified P62 and cMYC as downstream effectors of SNAT1. By activating the P62/cMYC-axis and target genes of cMYC, SNAT1 modulates the metabolism of melanoma cells depending on the glutamine level. SNAT1 and P62 are interaction partners. Conclusions: This finding newly suggests that SNAT1 may function as a sensor or receptor (“transceptor”) for glutamine rather than being a direct and primary glutamine transporter, and could open up new therapeutic options targeting melanoma cells. Full article

Background/Objectives: Acute myeloid leukemia (AML) remains a hematologic malignancy with poor prognosis. The neddylation inhibitor MLN4924 has demonstrated potent anti-leukemic activity in preclinical models, yet its clinical translation faces significant challenges. The aim of this study was to explore combination therapy strategies that could further enhance MLN4924’s anti-leukemia potential. Methods: AML cell lines used in this study were Kasumi-1 and MOLM-13. Cell viability was assessed using CCK-8 assays. mRNA and protein expression levels were determined through RT-qPCR and Western blot, respectively. Flow cytometry was employed to analyze surface markers (SLC1A5, CD11b, CD14, CD16), mitochondrial membrane potential (JC-1), and apoptosis (Annexin V-FITC/PI). In vivo efficacy was validated using an NCG mouse xenograft model. Transcriptomic profiling was performed to explore the potential mechanism by which MLN4924 in combination with V9302 inhibits leukemia. Results: Treatment with MLN4924 significantly upregulated key glutamine metabolic proteins, GLUL and the glutamine transporter SLC1A5, in AML cells. Knockdown of SLC1A5 significantly enhanced AML cell sensitivity to MLN4924. The combination of MLN4924 and the SLC1A5 inhibitor V9302 synergistically inhibited AML cell proliferation, induced monocytic differentiation, and promoted apoptosis. Transcriptomic analysis revealed that this combination therapy prominently suppressed the tricarboxylic acid (TCA) cycle. Conclusions: Neddylation inhibition induces compensatory upregulation of glutamine metabolism in AML. Co-targeting neddylation and glutamine transporter SLC1A5 synergistically exerts anti-leukemic effects, at least in part through disruption of the TCA cycle. This combination represents a novel and effective therapeutic strategy against AML. Full article

Background/Objectives: Glioblastoma (GBM) is the most aggressive primary brain tumor in adults and remains associated with poor prognosis despite multimodal therapy. Metabolic reprogramming, particularly increased dependence on glutamine, supports GBM bioenergetic, biosynthetic, and redox demands. This study aimed to systematically identify glutamine-associated metabolic regulators with prognostic relevance and biological plausibility in GBM. Methods: Transcriptomic data from TCGA and GTEx were analyzed using GEPIA2, with survival validation performed using the CGGA. Functional pathway enrichment, protein expression assessment, protein–protein interaction network analysis, tumor microenvironment evaluation, epigenetic profiling, and single-cell RNA sequencing validation were integrated to contextualize candidate genes. Pharmacogenomic correlation analysis and structure-based molecular docking were applied as supportive validation layers. Results: Ceruloplasmin (CP), Solute Carrier Family 25 Member 13 (SLC25A13), and Solute Carrier Family 38 Member 2 (SLC38A2) were selectively dysregulated and associated with poor clinical outcomes in GBM. CP was linked to redox regulation and stress-adaptive survival programs, SLC25A13 to mitochondrial metabolite exchange and glutamine-coupled nucleotide biosynthesis, and SLC38A2 to glutamine uptake, nutrient sensing, and mTORC1-MYC-associated growth signaling. Conclusions: CP, SLC25A13, and SLC38A2 emerge as clinically relevant glutamine-associated metabolic regulators in GBM, linking redox regulation, mitochondrial metabolite exchange, and glutamine-driven growth signaling. These findings highlight transport- and exchange-centered metabolic nodes as potential biomarkers and candidates for future metabolic targeting in GBM. Full article

Salinity stress severely limits rice productivity and grain quality worldwide. Although exogenous foliar application of titanium dioxide nanoparticles (nano-TiO₂) has been reported to enhance crop stress tolerance, its regulatory roles in yield formation and grain quality in rice varieties with differing salt tolerance are not well understood. In the present study, two contrasting rice varieties, viz., Jingliangyou 3261 (JLY3261; salt-tolerant) and Yuxiangyouzhan (YXYZ; salt-sensitive), were applied with five nano-TiO₂ foliar application treatments—viz., CK: water spray; Ti1: 15 mg L⁻¹; Ti2: 30 mg L⁻¹; Ti3: 45 mg L⁻¹; and Ti4: 60 mg L⁻¹—at the jointing and panicle initiation stages. Plants were irrigated with 0.3% saltwater to simulate salt stress. The results showed that Ti2 and Ti3 treatments led to 8.59% and 14.80% increases in grain yield in JLY3261 and YXYZ, respectively, compared with CK. Ti2 and Ti3 treatments significantly increased the leaf area index, net photosynthetic rate, and aboveground biomass of both varieties at the heading stage. Meanwhile, the activities of antioxidant enzymes such as superoxide dismutase and peroxidase, as well as nitrogen metabolism enzymes including nitrate reductase and glutamine synthetase, were improved with a substantial reduction in malondialdehyde contents. Application of nano-TiO₂ upregulated the expression of ion transport-related genes such as OsSOSs, OsNHXs and OsHKTs, thus improving leaf K⁺ accumulation and reducing Na⁺ content to optimize the K⁺/Na⁺ ratio. In addition, Ti2 and Ti3 treatments improved the milled rice rate, head rice rate, and protein content, while they decreased the chalkiness degree of both rice cultivars. Principal component analysis showed that the aboveground biomass at the heading stage was a core evaluation index for both varieties. Overall, foliar application of 30–45 mg L⁻¹ nano-TiO₂ was found to be effective regarding growth and yield improvement in rice under saline conditions. This study provides a theoretical basis for agro-management strategies for rice cultivation in saline–alkaline soils. Full article

Transport of Golgi-localized proteins from the ER is mediated by the coat protein complex II (COPII) and its members, COPII inner coat subunit Sec24 and Secretion-associated Ras-related GTPase 1 (Sar1). Sar1 and Sec24 recognize cytosolic N-termini of glycosyltransferases (GTs) that contain peptide signals required for incorporation into COPII-coated vesicles. Xyloglucan Xylosyltransferases (XXTs) are required for xyloglucan (XyGs) biosynthesis and must be transported to the Golgi for proper function. In this study, we demonstrated that XXTs interact with AtSar1 in the COPII complex but not with AtSec24, which was previously reported to be the main recruiter of cargo proteins into COPII-coated vesicles. The mutation of the arginine to glutamine residues of di-arginine motifs in the N-termini of XXTs caused protein mislocalization and significantly reduced the strength of the interaction with AtSar1. These mutations caused 90% of XXTs to either remain in the ER or localize to small non-Golgi compartments. In turn, such mislocalization significantly suppressed the recovery of XyGs biosynthesis in Arabidopsis thaliana (Arabidopsis) mutants (xxt1xxt2 and xxt3xxt4xxt5), failing to restore their root phenotypes to normal. Our results demonstrate the interaction between cargo and AtSar1, highlighting the critical role of di-arginine motifs in this interaction. These results provide new insights into the mechanism of ER-to-Golgi delivery of plant GTs, which significantly advances our understanding of polysaccharide biosynthesis in the Golgi and the enzymes responsible for it. Full article

Interferon-γ (IFNγ), a key inflammatory cytokine that orchestrates immune responses, also emerges as a regulator of cellular metabolism; however, in alveolar epithelial cells its impact on amino acid homeostasis remains poorly defined. Here, we investigated the effects of IFNγ on intracellular amino acid content and transmembrane transport in human alveolar epithelial A549 cells, focusing on the contribution of the JAK/STAT/IRF1 signaling axis. To this end, A549 WT and IRF1 knockout (IRF1 KO) cells were used to investigate IRF1 contribution, and baricitinib to evaluate the role of the JAK/STAT pathway. HPLC analysis reveals that in WT, but not in IRF1 KO cells, IFNγ markedly increases the intracellular concentration of many amino acids, including glutamine, glutamate, and several neutral and cationic amino acids, without affecting the cell volume, thus indicating true metabolic accumulation. The measurement of the transmembrane uptake of specific radiolabeled amino acids demonstrates a concomitant increase in transport Systems ASC, A, L, and y⁺ activity; an upregulation of the related transporters ASCT2, SNAT2, LAT1, and CAT1 has also been observed by means of qPCR analysis. Moreover, conditioned medium from SARS-CoV-2 spike-activated macrophages recapitulates IFNγ-driven amino acid remodeling in a JAK/STAT/IRF1-dependent manner. Overall, our findings identify IFNγ as a potent regulator of intracellular amino acid availability in alveolar epithelial cells through the modulation of the activity of membrane transporters. The observed IFNγ-reprogramming is IRF1 dependent, ascribing a crucial role to this transcription factor in linking inflammation and amino acid metabolism. Full article

Ureides; allantoate, allantoin, and amides; asparagine, and glutamine are the N₂ fixation products in soybean root nodules, and they are transported through xylem vessels. We estimated the transport rates of xylem constituents by multiplying nutrient concentrations by the water flow rate. Nodulated soybean plants were grown with an N-free solution under either 28 °C day/18 °C night or 28 °C day/28 °C night conditions, and diurnal changes in nutrient concentrations in xylem sap and transpiration rate were determined every 2 h. Under both conditions, xylem sap exudation rate and transpiration rate were high in light, and low, but not zero, in darkness. The sum of the xylem sap exudation rate and transpiration rate from detached shoots was almost the same as the water flow rate of intact plants at any time. All the N compounds exhibited a similar pattern: concentrations were high, but transport rates were lower at night. The proportions of N constituents were constant throughout the day and night. The composition and transport rate of xylem sap were not affected by night temperatures, except for cations. The results confirmed that the water flow rate and transport rate of xylem constituents can be estimated using detached roots and detached shoots. Full article

Intense physical activity imposes substantial oxidative, metabolic, and immunological stress on the human body. It is often accompanied by reductions in plasma glutamine levels, making this amino acid conditionally essential. Glutamine plays a vital role in energy production, nitrogen transport, acid–base balance, antioxidant defense, and immune function. It is required in the biosynthesis of neurotransmitters, nucleotides, nicotinamide-derived coenzymes, glutathione, and hexosamines, making it a candidate for supporting exercise recovery. In addition, glutamine may support key mechanisms involved in muscle adaptation and recovery during exercise-induced stress by contributing to redox balance, energy sensing, anabolic signaling, intestinal barrier integrity, and immune function. This narrative review aims to synthesize biochemical mechanisms underlying glutamine effects relevant to exercise and evaluate preclinical and clinical findings on supplementation outcomes, with emphasis on timing strategies. Preclinical findings demonstrate that glutamine can modulate protein synthesis, reduce oxidative stress, improve intestinal integrity, and attenuate immune and inflammatory disturbances. Limited preclinical data suggest that post-exercise supplementation may better resolve muscle and organ damage. Clinical trials, however, report heterogeneous outcomes: several studies show improvements in markers of intestinal permeability and intestinal epithelial damage, oxidative stress, muscle damage, and inflammation, whereas others report minimal or no effect, including limited influence on performance outcomes. Variability in timing protocols, participant characteristics, and measured endpoints contributes to inconsistent findings. Overall, glutamine demonstrates several biologically plausible mechanisms that could support recovery and overall health in active individuals, athletes, and specific clinical populations. However, current evidence remains insufficient to determine clear supplementation benefits or define an optimal timing strategy. Future research using standardized protocols and integrated biochemical and functional endpoints is needed to clarify timing effects. Until such evidence emerges, recommendations should remain individualized, considering athlete-specific needs. Full article

Glutamine metabolism has emerged as one of the most critical bioenergetic and biosynthetic programs sustaining leukemic cell growth, survival, stemness and therapeutic resistance. In both acute and chronic leukemias, including acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), malignant cells display a strong dependency on extracellular glutamine to support mitochondrial respiration, anabolic biosynthesis and redox homeostasis. This dependency is reinforced by oncogenic signaling networks, post-transcriptional metabolic regulation and microenvironmental adaptation within the bone marrow niche. Therapeutic strategies targeting glutamine utilization, including glutaminase inhibition, transporter blockade and enzymatic glutamine depletion, have demonstrated robust antileukemic activity in preclinical models, and early clinical efforts have begun to explore glutamine-directed interventions in myeloid neoplasms. However, metabolic plasticity, microenvironment-derived nutrient buffering and systemic toxicity remain significant limitations to clinical translation. This review provides a detailed synthesis of the biochemical framework of glutamine metabolism in leukemia, the molecular mechanisms enforcing glutamine addiction, the downstream functional consequences on proliferation, redox balance and leukemic stem cell biology, the current landscape of therapeutic strategies and emerging directions aimed at overcoming resistance and improving clinical efficacy. Full article

Mitochondria serve as central hubs of cellular metabolism, integrating catabolic and anabolic pathways through the controlled exchange of metabolites across their membranes. Although mitochondrial transport of several metabolites has been well documented, the mechanisms underlying the trafficking of fumarate, glutamine, and phosphoenolpyruvate as well as the role of the mitochondrial pyruvate kinase remain insufficiently represented in modern biochemistry textbooks. Here, we revisit the biochemical evidence supporting specific transport activities for these metabolites, discuss their physiological roles in major metabolic pathways, and highlight how foundational experimental studies have been overlooked in contemporary literature. Re-examining these mechanisms provides new insight into the dynamic interplay between mitochondrial function, cytosolic metabolism, and overall cellular homeostasis. Full article

Chronic stress is a major risk factor contributing to cellular changes in the brain that precipitate the emergence of various behavioral changes, including anxiety and anhedonia—symptoms relevant to mood disorders including major depression—however the sequence and trajectory of early molecular changes is poorly characterized. Using the chronic restraint stress (CRS) model in mice (N = 6–8/sex/group), we assessed the impact of 0, 7, 14, 21, 28, or 35 days of CRS at the behavioral level on the emergence of anxiety-like and anhedonia-like phenotypes. While 7 days of CRS was sufficient to induce anxiety-like behaviors in the PhenoTyper test, anhedonia-like deficits in the sucrose consumption test were only observed after 35 days of CRS. We also investigated the underlying molecular changes in the prefrontal cortex, a limbic brain region highly sensitive to stress, using Western blot and qPCR. We found that protein or RNA levels of several markers known to be implicated in the pathology of depression, and markers of synapses (post synaptic density protein 95 (PSD95), synapsin-1 (SYN1), vesicular glutamate transporter-1 (VGLUT1), and gephyrin (GPHN)); GABAergic inhibitory interneurons (somatostatin (SST), parvalbumin (PV), glutamic acid decarboxylase-67 (GAD67), and vasoactive intestinal peptide (VIP)); and astroglia (glial fibrillary acidic protein (GFAP), glutamate transporter-1 (GLT1), and glutamine synthase (GS)) were gradually reduced by CRS. Interestingly, all three astroglial markers were negatively correlated with anhedonia-like behaviors, while SYN1 and GPHN negatively correlated with anxiety-like behaviors. GLT1, VGLUT1, SYN1, and GAD67 negatively correlated with Z-emotionality scores. Exploratory between-marker correlations and integrative network analyses revealed that CRS effects might be driven by different compartments (synaptic, GABAergic and astroglial) depending on sex. Our study demonstrates that CRS induces dynamic changes that can be observed at the behavioral and molecular levels, and that male and female mice, while exhibiting similar symptoms, may experience different underlying pathologies. Full article

Background/Objectives: Metabolic reprogramming is an essential feature of tumors. Mitochondrial sirtuins SIRT3 and SIRT5 differently regulate glutamine metabolism with SIRT5 inhibiting glutaminase (GLS) and SIRT3 increasing glutamate dehydrogenase (GDH). Considering the important and interconnected role of glutamine, SIRT3 and SIRT5 for cancer growth and progression, our hypothesis is that a simultaneous modulation of SIRT3 and SIRT5 could represent a valid anti-tumoral strategy. Methods: wt and GLS1-silenced triple negative breast cancer spheroids were treated with 3-TYP, a selective SIRT3 inhibitor, and with MC3138, a new selective SIRT5 activator, both alone and in combination. The effects of such treatments on hypoxia, autophagy and mitophagy markers were determined by immunofluorescence and Western blot. Mitochondria morphology was studied by transmission electron microscopy (TEM) and mitochondrial ROS production by confocal analysis. Results: We observed that 3-TYP+MC3138 treatment decreased the size of spheroids by affecting HIF-1α, c-Myc, glutamine transporter SLC1A5 and autophagy (LC3II) and mitophagy (BNIP3) markers. Moreover, such treatments altered the morphology and conformation of the mitochondria. Finally, we also documented an increase in mitochondria reactive oxygen species (mtROS). Conclusions: The combined inhibition of SIRT3 and activation of SIRT5 greatly reduces the size of spheroids through the inhibition of hypoxic response, which is then followed by the alteration of the autophagic and mitophagic process and the toxic accumulation of mitochondrial ROS, representing a new anti-tumoral strategy. Full article

Background/Objectives: Synovial sarcoma (SS) is a malignant soft tissue neoplasm with good outcomes in adolescents with localized tumors, but poor outcomes in older adults and in advanced or metastatic cases. Targeting cancer metabolism, such as glutamine metabolism, is a promising therapeutic strategy. In this study, we investigated glutamine dependency in SS and assessed the therapeutic potential of inhibiting the glutamine transporter ASCT2 using V9302. Methods: Immunohistochemistry (IHC) was used to evaluate ASCT2 expression in SS and liposarcoma (LPS) specimen. The effects of glutamine deprivation and V9302 were examined in a SS cell line (HS-SY-II), patient-derived SS cells (SSH1), and a normal cell line (HEK293). Cell viability, apoptosis, and protein expression were assessed using the CCK-8 assay, flow cytometry, and Western blotting, respectively. The therapeutic efficacy of V9302 was evaluated in a xenograft model using IHC. Results: ASCT2 expression was elevated in SS tumor tissues compared with adjacent normal tissues and LPS specimens. Both the HS-SY-II cell line and SSH1 cells exhibited strong glutamine dependency for proliferation. V9302 selectively reduced HS-SY-II cell viability by suppressing the AKT/mTOR signaling pathway and inducing apoptosis via caspase-3 activation, with minimal effects on control cells. In vivo, V9302 administration significantly inhibited tumor growth without inducing systemic toxicity, and IHC of the treated tumors confirmed the suppression of the mTOR pathway and induction of apoptosis. Conclusions: Our findings suggest that SS is a glutamine-dependent malignancy and validate ASCT2 as a promising therapeutic target. The ASCT2 inhibitor V9302 demonstrated therapeutic efficacy both in vitro and in vivo, supporting its potential as a therapeutic agent for SS. Full article

Low Nitrogen Use Efficiency (NUE) remains a critical agricultural challenge, as an estimated 50–70% of applied nitrogen (N) is lost, resulting in negative environmental impacts and reduced crop production. To elucidate molecular mechanism controlling NUE in tomato (Solanum lycopersicum), we conducted a comprehensive genomic, transcriptomic, and functional analysis of the NPF, NRT2, and AMT transporter families under high-N commercial supply conditions. Our integrated analysis identified a shoot-to-root signaling mechanism where the plant’s metabolic performance systematically regulates N transport capacity. Under N sufficiency, the shoot exhibited reduced N assimilation, evidenced by NO₃⁻ accumulation (increased by 55.7%) and reduced Nitrate Reductase (NR) and Glutamine Synthetase (GS) activities (54.0% and 43.2% reduction, respectively), which correlated with a 42.3% reduction in chlorophyll synthesis capacity. This reduction in metabolic demand systematically triggered the downregulation of the key long-distance SlNPF transporters, SlNPF2.13 and SlNPF7.3, restricting N translocation and promoting significant root N accumulation (increased by 41.8%). Our data established that the leaf metabolic state is the systemic regulator of N transport and identified SlNPF2.13 and SlNPF7.3 as pivotal molecular checkpoints. These findings indicate that the manipulation of these transporters could serve as a valuable tool in molecular breeding programs to significantly enhance NUE in commercial tomato varieties. Full article

Pyrenophora tritici-repentis (Ptr), the causal agent of tan spot, is a necrotrophic fungus that represents a significant threat to wheat production worldwide. The development of resistant cultivars is limited by an incomplete understanding of wheat defence responses against Ptr. Here, weighted gene co-expression network analysis (WGCNA) was applied to RNA-seq data from resistant (Robigus) and susceptible (Hereward) wheat lines before and after Ptr infection to identify coordinated host responses. Eight co-expression modules were identified, three of which were linked to either resistance, susceptibility, or Ptr infection. The resistance-associated module was enriched with chloroplast ribosomal machinery genes (e.g., 50S ribosome-binding GTPase, L28, L6), and transcriptional regulators. This suggested that maintaining chloroplast function, coupled with large-scale transcriptional reprogramming, was important for resistance. The susceptibility-associated module indicated the high expression of post-transcriptional modifiers, including SGS3, RBX1, and SENPs. The Ptr-responsive module showed common responses in both genotypes and included several defence-related genes (nucleotide-binding domain leucine-rich repeat R-genes [NLRs], chitinases, beta-1,3-glucanases) and metabolic pathways, such as phenylpropanoid biosynthesis and nitrogen metabolism (phenylpropanoid ammonia lyase [PAL], cytochrome P450s, glutamine synthase, and ammonium transporters). These results define distinct and shared molecular networks that are linked to resistance and susceptibility, providing valuable candidate genes for functional validation that could ultimately be exploited to enhance wheat resilience against necrotrophic fungal pathogens. Full article