Search Results (110)

Isocitrate dehydrogenase 1 (IDH1) mutations are key drivers of glioma biology, influencing tumor aggressiveness and treatment response. To elucidate their molecular impact, we performed proteome analysis on patient-derived (PD) and U87MG glioma cell models with either mutant or wild-type IDH1. We quantified over 6000 protein groups per model, identifying 1594 differentially expressed proteins in PD-AS (IDH1_MUT) vs. PD-GB (IDH1_WT) and 904 in U87_MUT vs. U87_WT. Both IDH1_MUT models exhibited enhanced MHC antigen presentation and interferon signaling, indicative of an altered immune microenvironment. However, metabolic alterations were model-dependent: PD-AS cells shifted toward glycolysis and purine salvage, while U87_MUT cells retained oxidative phosphorylation, potentially due to D2-hydroxyglutarate (2OHG)-mediated HIF1A stabilization. We also observed a predominance of downregulated DNA repair proteins in IDH1_MUT models, particularly those involved in homologous recombination. In contrast, RB1 and ASMTL were strongly upregulated in both IDH1_MUT models, implicating them in DNA repair and cellular stress responses. We also found distinct expression patterns of proteins regulating histone methylation in IDH1_MUT cells, favoring increased methylation of H3K4, H3K9, and H3K36. A key driver of this may be the upregulation of SETD2 in PD-AS, an H3K4 and H3K36 trimethyltransferase linked to the recruitment of HIF1A as well as DNA mismatch repair proteins. This study uncovers candidate biomarkers and pathways relevant to glioma progression and therapeutic targeting, but also underscores the complexity of predicting glioma pathogenesis and treatment responses based on IDH1 mutation status. While proteome profiling provides valuable insights, a comprehensive understanding of IDH1_MUT gliomas will likely require integrative multi-omics approaches, including DNA/RNA methylation profiling, histone and protein post-translational modification analyses, and targeted DNA damage and repair assays. Full article

Isocitrate dehydrogenase (IDH) catalyzes the conversion of NAD(P)⁺ and isocitrate to NAD(P)H and α-ketoglutarate (αKG). The cytoplasmic enzyme IDH1 is important for producing NADPH for biosynthesis and for protecting against oxidative stress. IDH1 mutants, such as R132H found in glioblastomas and other types of human cancers, have a neomorphic activity that uses NADPH to reduce αKG to 2-hydroxyglutarate (2HG). 2HG interferes with the activity of important enzymes such as histone demethylases and TET demethylases. We hypothesized that Caenorhabditis elegans could be a good model system for studying oncogenic properties of mutant IDH1. To test this, we purified C. elegans cytoplasmic IDH-1 and two mutants, G98N and R133H, which correspond to human IDH1 mutants G97N and R132H, respectively. We found that the wild-type IDH-1 had similar kinetic properties to human IDH1, and it could produce small amounts of 2HG. We also found that the R133H mutant had a lower K_M for αKG than human R132H in steady-state enzyme kinetic experiments, and it produced almost exclusively 2HG in the presence of NADPH and αKG. The G98N mutant had a higher k_cat in the forward direction than the comparable human G97N mutant, and the G98N mutant produced a smaller amount of 2HG compared to the R133H mutant. These results suggest that C. elegans strains with IDH-1 mutations could be a good model system for studying the effects of 2HG in eukaryotic organisms. Full article

Brain tumors elicit complex neuropsychiatric disturbances that frequently occur prior to radiological detection and hinder differentiation from major psychiatric disorders. These syndromes stem from tumor-dependent metabolic reprogramming, neuroimmune activation, neurotransmitter dysregulation, and large-scale circuit disruption. Dinucleotide hypermethylation (e.g., IDH-mutant gliomas), through the accumulation of 2-hydroxyglutarate (2-HG), execute broad DNA and histone hypermethylation, hypermethylating serotonergic and glutamatergic pathways, and contributing to a treatment-resistant cognitive-affective syndrome. High-grade gliomas promote glutamate excitotoxicity via system Xc⁻ transporter upregulation that contributes to cognitive and affective instability. Cytokine cascades induced by tumors (e.g., IL-6, TNF-α, IFN-γ) lead to the breakdown of the blood–brain barrier (BBB), which is thought to amplify neuroinflammatory processes similar to those seen in schizophrenia spectrum disorders and autoimmune encephalopathies. Frontal gliomas present with apathy and disinhibition, and temporal tumors lead to hallucinations, emotional lability, and episodic memory dysfunction. Tumor-associated neuropsychiatric dysfunction, despite increasing recognition, is underdiagnosed and commonly misdiagnosed. This paper seeks to consolidate the mechanistic understanding of these syndromes, drawing on perspectives from neuroimaging, molecular oncology, neuroimmunology, and computational psychiatry. Novel approaches, including lesion-network mapping, exosomal biomarkers or AI-based predictive modeling, have projected early detection and precision-targeted interventions. In the context of the limitations of conventional psychotropic treatments, mechanistically informed therapies, including neuromodulation, neuroimmune-based interventions, and metabolic reprogramming, are essential to improving psychiatric and oncological outcomes. Paraneoplastic neuropsychiatric syndromes are not due to a secondary effect, rather, they are manifestations integral to the biology of a tumor, so they require a new paradigm in both diagnosis and treatment. And defining their molecular and circuit-level underpinnings will propel the next frontier of precision psychiatry in neuro-oncology, cementing the understanding that psychiatric dysfunction is a core influencer of survival, resilience, and quality of life. Full article

Background: L-2-hydroxyglutaric aciduria (L2HGA) is a rare autosomal recessive neurometabolic disorder caused by biallelic loss-of-function variants in the L-2-hydroxyglutarate dehydrogenase (L2HGDH) gene, leading to accumulation of L-2-hydroxyglutarate in the brain and other tissues. While various variants have been reported, the pathogenic mechanism of specific variants remains unclear. In this study, we aimed to investigate the molecular consequences of the c.905C>T p.(Pro302Leu) variant, identified in two siblings with typical symptoms of L2HGA, by analyzing its effects on protein localization and enzymatic activity in a cell model. Methods: HA-tagged wild-type and p.(Pro302Leu) mutant L2HGDH constructs were overexpressed in HEK293T cells. We assessed protein expression, subcellular localization, and enzymatic activity using Western blot analysis, immunofluorescence microscopy, and a specific enzyme assay measuring 2,6-dichloroindophenol (DCIP) reduction to assess L2HGDH enzymatic activity. Results: Western blotting showed that wild-type L2HGDH exists primarily in the processed, mature mitochondrial form, whereas the p.(Pro302Leu) mutant remained largely in the unprocessed precursor form. Immunofluorescence and differential centrifugation revealed that wild-type protein localized to mitochondria, while the mutant protein accumulated in the cytoplasm in a diffuse or punctate pattern. Enzyme activity assays demonstrated that the mutant retained <30% of wild-type activity. Conclusions: These findings indicate that the p.(Pro302Leu) variant leads to aggregation of mislocalized protein, thereby impairing L2HGDH function rather than decreasing enzymatic function. This study provides clinical and molecular evidence supporting the pathogenicity of this previously reported mutation and highlights the importance of mitochondrial import for enzyme functionality in L2HGA. Full article

First-line treatment for localized prostate cancer (PCa) includes radical prostatectomy (RP) for high-risk disease. However, in many cases, patients experience biochemical recurrence (BCR), heralded by rising prostate specific antigen (PSA) levels in the serum. Our goal was to identify metabolic pathways that are disrupted in BCR to determine potential targets of therapy. We conducted metabolomic analysis in prostate tissue from the tumors of 74 patients who underwent prostatectomy as treatment for localized PCa and correlated levels of metabolites with clinical and non-clinical factors. Cholesterol and triglycerides were upregulated in Hispanic vs. non-Hispanic and in obese vs. non-obese individuals, respectively. Both lipids and non-lipids were altered with increasing Gleason grades and clinical stages. High post-RP PSA (>0.1 ng/mL) indicated recurrence (p = 0.0094) and correlated with alterations in 141 metabolites including 114 lipids and 26 non-lipid molecules. The largest increase with high post-RP PSA was in 2-hydroxyglutaric acid (2-HG), a product of the tricarboxylic acid (TCA) cycle, that had previously been established as an oncometabolite in other cancers. 2-HG was highly selective and specific for high post-RP PSA (AUC = 0.8526; p = 0.0002) while Kaplan–Meier curves indicated that among patients who recurred, high 2-HG in the tumor reduced time-to-recurrence from 84 months (for those with low 2-HG) to 38 months (for those with high 2-HG). The addition of D2HG, an enantiomer of 2-HG, increased the growth rate of LNCaP and C4 cells, and also increased Akt and ERK phosphorylation. 2-HG is upregulated in PCa tumors from patients who experience high post-RP PSA indicative of recurrence. Future studies may target this metabolite to prevent recurrent disease. Full article

A periplasmic D-malate:cytochrome c oxidoreductase (DMCO) was identified in Ectopseudomonas oleovorans CECT5344, utilizing 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT) as an artificial electron acceptor. The assay was adapted for a spectrophotometric or native polyacrylamide gel electrophoresis (PAGE) analysis. The DMCO-encoding gene (BN5_4044) was cloned and expressed in Escherichia coli, enabling a partial purification and biochemical characterization. In addition to D-malate, the enzyme oxidizes D-2-hydroxyglutarate and, to a lesser extent, D-lactate, with cytochrome c also serving as an electron acceptor. DMCO requires Zn²⁺ for activity and exists as a dimer, as determined by gel filtration. The in vitro reconstitution of the electron transfer from D-malate to oxygen was achieved using spheroplasts, enriched periplasmic fractions, and cytochrome c. This extracytoplasmic respiration, unique among homologs of this protein, may eliminate the need for a dedicated inner membrane transporter, thereby avoiding potential upstream respiratory bottlenecks. In the context of bioremediation, and particularly regarding the cyanide metabolism, this D-malate oxidation to oxaloacetate facilitates detoxification by forming the corresponding cyanohydrin, which can be subsequently assimilated for growth. Full article

Background/Objectives: Isocitrate dehydrogenase (IDH) mutations are hallmark features in subsets of gliomas, producing the oncometabolite D-2-hydroxyglutarate (2HG). Although IDH mutations are associated with better clinical outcomes, their relationship with tumor progression is complex. This study aimed to investigate, in vitro and in vivo, the phenotypic consequences of IDH mutation and 2HG exposure in glioblastoma (GBM) under normoxic and hypoxic conditions and under temozolomide (TMZ) and radiation exposure. Methods: Experiments were conducted using IDH-wildtype (IDH-wt) and IDH-mutant (IDH-mut) glioma cell lines under controlled oxygen conditions. Functional assays included cell viability, cell cycle analysis, apoptosis profiling, migration, and surface marker expression via flow cytometry. Orthotopic xenografts were established in immunocompromised mice to assess in vivo tumor growth and morphology, followed by MRI and histological analysis. Treatments included TMZ, radiation, and 2HG at varying concentrations. Statistical analyses were performed using SPSS and RStudio. Results:IDH-wt cells exhibited faster proliferation and greater adaptability under hypoxia, while IDH-mut cells showed cell cycle arrest and limited growth. 2HG recapitulated IDH-mut features in IDH-wt cells, including increased apoptosis under TMZ, reduced proliferation, and altered CD24/CD44 expression. In vivo, IDH-wt tumors were larger and more infiltrative, while 2HG administration reduced tumor volume and promoted compact morphology. Notably, migration was initially similar across genotypes but increased in IDH-mut and 2HG-treated IDH-wt cells over time, though suppressed under therapeutic stress. Conclusions: IDH mutation and 2HG modulate glioma cell biology, including cell cycle dynamics, proliferation rates, migration, and apoptosis. While the IDH mutation and its metabolic product confer initial growth advantages, they enhance treatment sensitivity and reduce invasiveness, highlighting potential vulnerabilities for targeted therapy. Full article

IDH-mutant gliomas (IMGs) are a unique subset of diffuse gliomas that follow a relatively indolent course compared to IDH-wildtype glioblastoma (GBM) but inevitably progress, often to a higher histologic grade. Current standard therapies, including surgery, chemoradiation, and the recently approved mutant IDH inhibitor (mIDHi) vorasidenib, provide limited disease control and are not curative. Given the immunosuppressive tumor microenvironment (TME) driven by the mutant IDH enzyme and its associated oncometabolite 2-hydroxyglutarate (2-HG), novel immunotherapies offer a promising avenue for treatment. The goal of this paper is to review the main immunologic characteristics that distinguish IMG from GBM, including reduced T cell infiltration and function, fewer myeloid cells, and increased immune-dampening signaling. We also evaluate the preclinical and clinical evidence for immunotherapeutic approaches with the most potential to induce meaningful clinical activity, such as immune checkpoint inhibitors, CAR T cells, tumor vaccines, myeloid redirection, and oncolytic viruses. Despite significant advances in immunotherapy for IMG, fundamental questions persist, including optimal timing and combination strategies, mechanisms underpinning treatment resistance, and strategies to overcome the suppressive microenvironment. Future exploration of these treatment modalities, with a focus on mitigating soluble immunosuppressive factors in the TME, enhancing in situ T cell persistence, and leveraging novel antigen targets, is critical for advancing the state of therapy for this presently incurable group of tumors. Full article

Background: Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are enzymes that catalyze the oxidative decarboxylation of isocitrate to alpha-ketoglutarate (α-KG), which is essential for many metabolic processes, including some steps in DNA repair. In tumors, notably in gliomas, IDH1 and IDH2 are frequently mutated. The mutation found in different cancers is functionally active, causing, instead of α-KG, the formation of 2-hydroxyglutarate (2-HG), which inhibits α-KG-dependent enzymes. Gliomas harboring mutated IDH1/2 show a better prognosis than IDH1 wild-type (wt) tumors of the same grade, which might result from the inhibition of DNA repair functions. A DNA repair enzyme dependent on α-KG is alkB homolog 2 (ALKBH2), which removes several lesions from DNA. These findings prompted us to investigate the response of glioma cells to artesunate (ART), a plant ingredient with genotoxic and anticancer activity currently used in several trials. Materials and Methods: We used isogenic glioblastoma cell lines that express IDH1 wild-type or, based on a TET-inducible system, the IDH1 mutant (mt) protein, and treated them with increasing doses of artesunate. We also treated glioblastoma cells with 2-HG, generated ALKBH2 knockout cells, and checked their sensitivity to the cytotoxic effects of artesunate. Results: We show that the cell-killing effect of ART is enhanced if the IDH1 mutant (R132H) is expressed in glioblastoma cells. Further, we show that 2-HG imitates the effect of IDH1mt as 2-HG ameliorates the cytotoxicity of ART. Finally, we demonstrate that the knockout of ALKBH2 causes the sensitization of glioblastoma cells to ART. Conclusions: The data indicate that ALKBH2 protects against the anticancer effect of ART, and the mutation of IDH1/2 commonly occurring in low-grade gliomas sensitizes to ART via an ALKBH2-dependent mechanism. The data support the use of ART in the therapy of IDH1/2-mutated cancers both in combination with chemotherapy and adjuvant treatment. Full article

This case series presents four pediatric patients who developed tracheal complications after prolonged invasive mechanical ventilation. The first case involved an 11-year-old girl with severe hypoxic encephalopathy who developed extensive ulcerative granulation tissue obstructing 60% of the tracheal lumen. The second case was that of a 6-year-old boy with ACTA1-related nemaline myopathy who experienced recurrent tracheal obstruction due to granulomatous tissue formation. The third case involved a 9-year-old boy with hydroxyglutaric aciduria and a large plug obstructing his trachea. The last case involved a 19-year-old female with lissencephaly who developed a tracheoesophageal fistula. These cases highlight the importance of regular surveillance and early intervention in managing tracheal complications in pediatric patients with complex chronic conditions requiring long-term mechanical ventilation. The authors emphasize the need for specialized care and routine endoscopic examinations in order to prevent and address potentially life-threatening complications in this vulnerable patient population. Full article

Schistosomes are intravascular parasitic worms that cause the debilitating tropical disease schistosomiasis, affecting >200 million people worldwide. How the worms survive within the body of immunocompetent hosts for many years is unclear. Here, using chromatography and mass spectrometry, we report on the ex vivo ability of adult Schistosoma mansoni worms to modulate the levels of 27 small molecule (often immunomodulatory) metabokines in murine plasma. Schistosomes significantly alter the relative amounts of most (16) of these molecules. Three (inosine, genistein, and glucose) are significantly decreased in the presence of the parasites. While levels of several immunomodulatory metabolites from the kynurenine pathway (kynurenine, kynurenic acid, and xanthurenic acid) remain unchanged, levels of anthranilate (an endogenous regulator of innate immunity) are significantly increased. Of particular interest are increases in levels of metabolites that are known to skew immune responses in a manner that is seen following natural schistosome infection, such as by promoting Th2 immunity (succinate), Treg generation (lactate) and M2 macrophage polarization (lactate and succinate). In addition, significant increases are also observed for 2-hydroxyglutarate, adenine, hypoxanthine, xanthine, myoinositol, betaine and N-acetylglucosamine. Each of these compounds can have immunosuppressive effects that could impact host immunological status and contribute to schistosome survival. Full article

Background/Objectives: In recent years, interest in studying changes in cancer metabolites has resulted in significant advances in the metabolomics field. Glioblastoma remains the most aggressive and lethal brain malignancy, which presents with notable metabolic reprogramming. Methods: We performed literature research from the PubMed database and considered research articles focused on the key metabolic pathways altered in glioblastoma (e.g., glycolysis, lipid metabolism, TCA cycle), the role of oncometabolites and metabolic plasticity, and the differential expression of metabolites in glioblastoma. Currently used metabolomics approaches can be either targeted, focusing on specific metabolites and pathways, or untargeted, which involves data-driven exploration of the metabolome and also results in the identification of new metabolites. Data processing and analysis is of great importance and can be improved with the integration of machine learning approaches for metabolite identification. Results: Changes in α/β-glucose, lactate, choline, and 2-hydroxyglutarate were detected in glioblastoma compared with non-tumor tissues. Different metabolites such as fumarate, tyrosine, and leucine, as well as citric acid, isocitric acid, shikimate, and GABA were detected in blood and CSF, respectively. Conclusions: Although promising new technological and bioinformatic approaches help us understand glioblastoma better, challenges associated with biomarker availability, tumor heterogeneity, interpatient variability, standardization, and reproducibility still remain. Metabolomics research, either alone or combined with genomics or proteomics (i.e., multiomics) in glioblastoma, can lead to biomarker identification, tracking of metabolic therapy response, discovery of novel metabolites and pathways, and identification of potential therapeutic targets. Full article

Introduction: Allergic rhinitis (AR) is largely driven by IgE-induced immune cell activation, which promotes allergen-induced upper airway inflammation. The regulatory mechanisms of IgE synthesis in AR are poorly understood. Several analyses associate single nucleotide polymorphisms (SNPs) which reduce the expression of the D2HGDH gene with AR. D2HGDH encodes an enzyme that converts D-2-hydroxyglutarate (D2HG) to α-ketoglutarate (α-KG). This study aims to clarify the relationship between AR and SNPs in D2HGDH. Methods: Mice were treated with vehicle control or octyl-D2HG prior to intranasal exposure to Alternaria alternata. Draining lymph nodes (dLNs) were then evaluated for IgE-producing cells and T-cell polarization. Next, mice were exposed to intranasal Alternaria on days 0, 10, 20, and 27–30 and were treated intranasally with octyl-D2HG or vehicle control on days 20 and 27. Nasal inflammation was analyzed in nasal lavage fluid (NLF) cellularity and antigen-specific IgE production. Results: The administration of D2HG prior to Alternaria exposure suppressed IgE synthesis (p < 0.01) and Th2 cell polarization (p < 0.01) in dLNs. In a murine model of AR, D2HG administration reduced overall cellular infiltrates and eosinophils in NLF. Further, antigen-specific IgE in NLF was significantly reduced in mice treated with D2HG (p < 0.05). Conclusions: An analysis of the regulatory landscape surrounding the rs34290285 SNP demonstrates that the downregulation of D2HGDH expression reduces the risk of AR. Downregulation of D2HGDH likely results in accumulation of D2HG intracellularly, suggesting that D2HG is protective against allergic rhinitis. We show that the administration of D2HG impairs IgE production, leading to the amelioration of allergic sinonasal inflammation in a murine model of AR. These findings suggest a causal relationship between D2HGDH expression, D2HG levels, and allergic rhinitis risk. Full article

Inflammatory bowel disease remains a significant challenge in clinical settings. This study investigated the therapeutic potential of sea cucumber ovum hydrolysates (SCH) in a dextran sulfate sodium (DSS)-induced colitis mouse model. SCH, defined by its elevated stability and solubility, with a molecular weight below 1000 Da, significantly alleviated DSS-induced colitis, as evidenced by enhanced splenic index, reduced colonic damage, and diminished serum pro-inflammatory cytokines. Furthermore, macrogenomic analysis demonstrated that SCH increased beneficial gut microbes and decreased pro-inflammatory bacteria. Furthermore, metabolomic analysis of colonic tissues identified elevated levels of anti-inflammatory metabolites, such as Phenyllactate, 2-Hydroxyglutarate, and L-Aspartic acid, in colitis mice after oral administration of SCH. In conclusion, SCH represents a promising candidate for the treatment of colitis. Full article

The hydroxylated perhydroquinoxaline 14 was designed by conformational restriction of the prototypical κ receptor agonist U-50,488 and the introduction of an additional polar group. The synthesis of 14 comprised ten reaction steps starting from diethyl 3-hydroxyglutarate (4). The first key step was the diastereoselective establishment of the tetrasubstituted cyclohexane 7 by the reaction of dialdehyde 6 with benzylamine and nitromethane. The piperazine ring was annulated by the reaction of silyloxy-substituted cyclohexanetriamine 8 with dimethyl oxalate. The pharmacophoric structural elements characteristic for κ receptor agonists were finally introduced by functional group modifications. The structure including the relative configuration of the tetrasubstituted cyclohexane derivative (2r,5s)-7a and the perhydroquinoxaline 9 was determined unequivocally by X-ray crystal structure analysis. The hydroxylated perhydroquinoxaline 14 showed moderate κ receptor affinity (K_i = 599 nM) and high selectivity over μ, δ, σ₁, and σ₂ receptors. An ionic interaction between the protonated pyrrolidine of 14 and D138 of κ receptor anchors 14 in the κ receptor binding pocket. Full article