Liquid Chromatography Coupled With Mass Spectrometry Research Articles

Activation of the non-neuronal cholinergic cardiac system by hypoxic preconditioning protects isolated adult cardiomyocytes from hypoxia/reoxygenation injury.

Activation of the vagus nerve mediates cardioprotection and attenuates myocardial ischemia/reperfusion (I/R) injury. In response to vagal activation, acetylcholine (ACh) is released from the intracardiac nervous system (ICNS) and activates intracellular cardioprotective signaling cascades. Recently, however, a non-neuronal cholinergic cardiac system (NNCCS) in cardiomyocytes has been described as an additional source of ACh. To investigate whether the NNCCS mediates cardioprotection in absence of vagal and ICNS activation. For that, we used a reductionist approach of isolated adult rat ventricular cardiomyocytes in absence of neuronal cells with hypoxic preconditioning (HPC) as protective stimulus. Adult rat ventricular cardiomyocytes were isolated, absence of neuronal cells was confirmed, HPC was induced by 10/20 min hypoxia/reoxygenation (H/R) before subjection to 30/5 min H/R to simulate I/R injury. Cardiomyocyte viability was assessed by trypan blue staining. Intra- and extracellular ACh was quantified using liquid chromatography-coupled mass spectrometry at baseline, after HPC, after hypoxia, and after reoxygenation, respectively. In a subset of experiments, muscarinic/nicotinic ACh receptor (mAChR/nAChR) antagonists were added during HPC or during H/R. Cardiomyocyte viability at baseline (69±4%) was reduced by H/R (10±3%). With HPC cardiomyocyte viability was preserved after H/R (25±6%). Intra- and extracellular ACh increased during hypoxia, HPC further increased both intra- and extracellular ACh (from 0.9±0.7 to 1.5±1.0 nmol/mg; from 0.7±0.6 to 1.1±0.7 nmol/mg). Addition of mAChR and nAChR antagonists during HPC had no impact on HPC´s protection, however protection was abrogated when antagonists were added during H/R (cardiomyocyte viability after H/R: 23±5%; 13±4%). Activation of the NNCCS is involved in cardiomyocyte protection: HPC increases intra- and extracellular ACh during H/R, and m-/nAChRs are causally involved in HPC´s cardiomyocyte protection during H/R. The interplay between upstream ICNS activation and the NNCCS activation to myocardial cholinergic metabolism and cardioprotection needs to be investigated in future studies.

Phytochemical screening, antioxidant properties, and photo-protective activities of Salvia balansae de Noé ex Coss

Abstract The present study evaluated the potential of Salvia balansae from the Aures Mountains as a source of natural bioactive compounds. Leaves, flowers, and stems were extracted separately using methanol, ethanol, and acetone. Phenolic compounds were quantified colorimetrically and identified using liquid chromatography coupled with mass spectrometry (LC-MS). Antioxidant capacity was assessed using six different in vitro assays, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 1,1-diphenyl-1-picrylhydrazyl, cupric reducing antioxidant capacity, ferric reducing antioxidant power, ferrous ion chelating, and phenanthroline assay, while the photo-protective capacity was evaluated using the sun protective factor. The methanolic flower extracts revealed the highest O-diphenol and phenolic levels (287.9 ± 0.50 and 147.87 ± 0.21 µg GAE/mg, respectively), whereas the acetonic and ethanolic leaf extracts contained the highest flavonoid (72.17 ± 0.12 μg QE/mg) and flavonol (35.28 ± 0.05 μg QE/mg) levels, respectively. LC-MS was used to identify 18 phenolics, including quinic acid (5.051–69.69 ppm), luteolin-7-o-glucoside (7.802–44.917 ppm), apigenin-7-o-glucoside (3.751–68.507 ppm), and cirsiliol (2.081–15.608 ppm), distinguishing this Aures taxon. Principal component analysis and unweighted pair-group method with arithmetic mean revealed variability in phytochemicals, antioxidant properties, and photo-protective activity influenced by biological activities and the compound content. Overall, S. balansae demonstrated promising photo-protective capacity, the presence of key bioactive compounds, and wide-ranging antioxidant potential, presenting this endemic plant as a valuable source of natural antioxidants and photo-protective agents with pharmaceutical and cosmetic applications.

First insight about the ability of specific glycerophospholipids to discriminate non-small cell lung cancer subtypes.

Introduction: Discrimination between adenocarcinoma (ADC) and squamous cell carcinoma (SCC) subtypes in non-small cell lung cancer (NSCLC) patients is a significant challenge in oncology. Lipidomics analysis provides a promising approach for this differentiation. Methods: In an accompanying paper, we explored oxPCs levels in a cohort of 200 NSCLC patients. In this research, we utilized liquid chromatography coupled with mass spectrometry (LC-MS) to analyze the lipidomics profile of matching tissue and plasma samples from 25 NSCLC patients, comprising 11 ADC and 14 SCC cases. This study builds upon our previous findings, which highlighted the elevation of oxidised phosphatidylcholines (oxPCs) in NSCLC patients. Results: We identified eight lipid biomarkers that effectively differentiate between ADC and SCC subtypes using an untargeted approach. Notably, we observed a significant increase in plasma LPA 20:4, LPA 18:1, and LPA 18:2 levels in the ADC group compared to the SCC group. Conversely, tumour PC 16:0/18:2, PC 16:0/4:0; CHO, and plasma PC 16:0/18:2; OH, PC 18:0/20:4; OH, PC 16:0/20:4; OOH levels were significantly higher in the ADC group. Discussion: Our study is the first to report that plasma LPA levels can distinguish between ADC and SCC patients in NSCLC, suggesting a potential role for LPAs in NSCLC subtyping. This finding warrants further investigation into the mechanisms underlying these differences and their clinical implications.

Observations from a decade of oligonucleotide bioanalysis by LC-MS.

There is a growing need for efficient bioanalysis of oligonucleotide therapeutics. This broad class of molecules presents numerous challenges relative to traditional small molecule therapeutics. Methodologies including ligand-binding assays or polymerase chain reaction may be fit-for-purpose in many instances, but liquid chromatography coupled to mass spectrometry (LC-MS) often delivers the best balance of sensitivity and selectivity. Over the last decade, we have engaged with many such molecules and derived insights into challenges and solutions. Herein, we provide four case studies illustrating challenges we have encountered. These issues include low or variable analyte recovery, poor resolution from related species, chromatographic abnormalities or challenging sensitivity. We present a summary of considerations, based on these experiences, to assist others working in the area.

Systemic acylcarnitine levels are affected in response to multiple injuries and hemorrhagic shock - an analysis of lipidomic changes in a standardized porcine model.

Along with recent advances in analytical technologies, TCA-cycle intermediates are increasingly identified as promising makers for cellular ischemia and mitochondrial dysfunction during hemorrhagic shock (HS). For traumatized patients, the knowledge of the role of lipid oxidation substrates is sparse. In this study, we aimed to analyze the dynamics of systemic acylcarnitine (AcCa) release in a standardized polytrauma model with HS. 52 male pigs (50 ± 5 kg) were randomized into two groups: Group IF (isolated fracture) was subject to a standardized femur shaft fracture. Group PT (polytrauma) was subject to a femur fracture, followed by blunt chest trauma, liver laceration and a pressure controlled hemorrhagic shock for 60 min. Resuscitation was performed with crystalloids. Fractures were stabilized by intramedullary nailing. Venous samples were collected at 6 timepoints (baseline, trauma, resuscitation, 2 h, 4 h and 6 h). Lipidomic analysis was performed via liquid chromatography coupled mass spectrometry. Measurements were collated with clinical markers and near-infrared spectrometry measurements (NIRS) of tissue perfusion. Longitudinal analyses were performed with linear mixed models and spearman's correlations were calculated. A p-value of 0.05 was defined as threshold for statistical significance. From a total of 303 distinct lipids, we identified two species of long-chain AcCas. Both showed a highly significant (p < 0.001) two-fold increase after HS in Group PT that promptly normalized after resuscitation. This increase was associated with a significant decrease of the base excess (p = 0.005) but recovery after resuscitation was faster. For both AcCas, there were significant correlations with decreased muscle tissue oxygen delivery (p = 0.008, p = 0.003) and significant time-lagged correlations with the increase of creatine kinase (p < 0.001, p < 0.001). Our results point to plasma AcCas as a possible indicator for mitochondrial dysfunction and cellular ischemia in HS. The more rapid normalization after resuscitation in comparison to acid base changes may warrant further investigation. Experimental Animal Model. N/A.

Gamma radiation-induced degradation of Acid Violet 49 in the presence of hydrogen peroxide (H2O2) in an aqueous medium

Abstract The present study is about the effect of gamma radiations on the degradation of Acid Violet 49 (AV49) in the presence of H2O2 (γ/H2O2). The Cs-137 radiation source was calibrated to irradiate the aqueous solution of AV49 within the 1 kGy, 5 kGy &amp; 10 kGy dose range. The results showed that 50–150 mg/L of AV49 was effectively degraded by γ radiation (85 %), however, the concentration of H2O2 in the range of 0.2–0.6 mL promoted degradation to 90 % and 98 %, respectively. It was observed that all absorption bands declined with rising irradiation dose and disappeared completely after 10 kGy applied dose. pH conditions (3, 5,7, and 9) were used in the radio-lytic degradation of AV49, the results showed that the best degradation efficiency has been found for pH 9. The optimum degradation rate is higher (98 %) with a 50 mg/L concentration of AV49, 0.6 mL H2O2, and pH 9 at a 10 kGy absorbed dose. In addition, the influence of various parameters on the rate of degradation such as the effect of irradiation dose, pH, H2O2, and dye (AV49) concentration was also studied. Furthermore, the removal of total organic carbon TOC was not as effective as that of the AV 49. Total nitrogen TN was not completely removed even at high dosage. Radio-lytic degradation of AV49 was analyzed by using Fourier transform infrared spectroscopy (FTIR) and liquid chromatography coupled to mass spectrometry (LC-MS) as an analytical technique. Results revealed that the proposed methodology for degradation of dyes is effective and probably could be applied for the removal of other toxic pollutants.

Anti-inflammatory, healing and antiophidic potential of Jatropha mollissima (Pohl) Baill. (Euphorbiaceae): From popular use to pharmaceutical formulation in gel

Jatropha mollissima (Pohl) Baill. (Euphorbiaceae) is widely used in traditional medicine to treat inflammatory disorders. So, a topical gel containing the hydroethanolic extract of its leaves was developed and evaluated for its anti-inflammatory, wound healing, and antiophidic properties in mice. First, the chemical profile of different parts of the plant was characterized by liquid chromatography coupled to mass spectrometry (LC-MS) using molecular networking. In the leaf extract, 11 compounds were characterized, with a particular emphasis on the identification of flavonoids. The gel efficiently inhibited carrageenan-induced paw edema, as well as acute and chronic croton oil-induced ear edema models, thereby reducing inflammatory and oxidative parameters in inflamed tissues. Besides anti-inflammatory activity, the herbal gel showed significant wound healing activity. The edematogenic, hemorrhagic and dermonecrotic activities induced by Bothrops jararaca snake venom were effectively inhibited by the treatment with J. mollissima gel. The association with the herbal gel improved in up to 90% the efficacy of commercial snake antivenom in reduce venom-induced edema. Additionally, while antivenom was not able to inhibit venom-induced dermonecrosis, treatment with herbal gel reduced in 55% the dermonocrotic halo produced. These results demonstrate the pharmacological potential of the herbal gel containing J. mollissima extract, which could be a strong candidate for the development of herbal products that can be used to complement the current antivenom therapy against snake venom local toxicity.

Liquid chromatography coupled to mass spectrometry metabolomic analysis of cerebrospinal fluid revealed the metabolic characteristics of moyamoya disease.

Metabolomics has found extensive applications in the field of neurological diseases, significantly contributing to their diagnosis and treatment. However, there has been limited research applying metabolomics to moyamoya disease (MMD). This study aims to investigate and identify differential metabolites associated with MMD. We employed a liquid chromatography coupled with mass spectrometry (LC-MS) approach, complemented by univariate and multivariate analyses, to discern metabolic biomarkers in cerebrospinal fluid samples. We then compared these biomarkers between MMD patients and healthy controls (Ctl). Sixteen patients diagnosed with MMD via cerebral angiography and eight healthy controls were enrolled in this study. Comparative analyses, including univariate and multivariate analyses, correlation studies, heatmaps, Volcano Plots, and KEGG pathway enrichment, were performed between MMD patients and controls. As a result, we identified 129 significant differential metabolites in the cerebrospinal fluid between MMD patients and controls. These metabolic biomarkers are associated with various pathways, with notable involvement in purine and pyrimidine metabolism. Utilizing an LC-MS-based metabolomics approach holds promise for enhancing the clinical diagnosis of MMD. The identified biomarkers offer potential avenues for the development of novel diagnostic methods for MMD and offer fresh insights into the pathogenesis of the disease.

METTL1 mediated tRNA m7G modification promotes leukaemogenesis of AML via tRNA regulated translational control

BackgroundRNA modifications have been proven to play fundamental roles in regulating cellular biology process. Recently, maladjusted N7-methylguanosine (m7G) modification and its modifiers METTL1/WDR4 have been confirmed an oncogene role in multiple cancers. However, the functions and molecular mechanisms of METTL1/WDR4 in acute myeloid leukemia (AML) remain to be determined.MethodsMETTL1/WDR4 expression levels were quantified using qRT-PCR, western blot analysis on AML clinical samples, and bioinformatics analysis on publicly available AML datasets. CCK-8 assays and cell count assays were performed to determine cell proliferation. Flow cytometry assays were conducted to assess cell cycle and apoptosis rates. Multiple techniques were used for mechanism studies in vitro assays, such as northern blotting, liquid chromatography-coupled mass spectrometry (LC–MS/MS), tRNA stability analysis, transcriptome sequencing, small non-coding RNA sequencing, quantitative proteomics, and protein synthesis measurements.ResultsMETTL1/WDR4 are significantly elevated in AML patients and associated with poor prognosis. METTL1 knockdown resulted in reduced cell proliferation and increased apoptosis in AML cells. Mechanically, METTL1 knockdown leads to significant decrease of m7G modification abundance on tRNA, which further destabilizes tRNAs and facilitates the biogenesis of tsRNAs in AML cells. In addition, profiling of nascent proteins revealed that METTL1 knockdown and transfection of total tRNAs that were isolated from METTL1 knockdown AML cells decreased global translation efficiency in AML cells.ConclusionsTaken together, our study demonstrates the important role of METTL1/WDR4 in AML leukaemogenesis, which provides a promising target candidate for AML therapy.

Targeted Metabolic Investigation of Ligandrol and Analytical Methods Validation for Its Main Long-term Metabolite.

Prompted by the need for related analytical reference material in the frame of the fight against doping in sports, synthetic efforts towards the main long-term bishydroxylated metabolite (LGD-LTM1) of the nonsteroidal selective androgen receptor modulator (SARM) ligandrol have produced related derivatives that were exploited for a targeted metabolite analysis of urine samples obtained in the course of previous excretion studies of this SARM. Further clarifying ligandrol's metabolic profile, the availability of synthetic reference material permitted the structural elucidation of a previously reported pyrrolidinone-type metabolite and revealed its potential analytical utility as an additional long-term marker. Moreover, synthetic reference material enabled the comparison and validation of liquid chromatography coupled with mass spectrometry (LC-MS)-based and gas chromatography coupled with mass spectrometry (GC-MS)-based detection and identification methods focusing on the LGD-LTM1 marker.

Facile Method for Determining Lanthipeptide Stereochemistry.

Lanthipeptides make up a large group of natural products that belong to the ribosomally synthesized and post-translationally modified peptides (RiPPs). Lanthipeptides contain lanthionine and methyllanthionine bis-amino acids that have varying stereochemistry. The stereochemistry of new lanthipeptides is often not determined because current methods require equipment that is not standard in most laboratories. In this study, we developed a facile, efficient, and user-friendly method for detecting lanthipeptide stereochemistry, utilizing advanced Marfey's analysis with detection by liquid chromatography coupled with mass spectrometry (LC-MS). Under optimized conditions, 0.05 mg of peptide is sufficient to characterize the stereochemistry of five (methyl)lanthionines of different stereochemistry using a simple liquid chromatography setup, which is a much lower detection limit than current methods. In addition, we describe methods to readily access standards of the three different methyllanthionine stereoisomers and two different lanthionine stereoisomers that have been reported in known lanthipeptides. The developed workflow uses a commonly used nonchiral column system and offers a scalable platform to assist antimicrobial discovery. We illustrate its utility with an example of a lanthipeptide discovered by genome mining.

Synthesis, Detection, and Metabolism of Pyridone Ribosides, Products of NAD Overoxidation.

Pyridone-containing adenine dinucleotides, ox-NAD, are formed by overoxidation of nicotinamide adenine dinucleotide (NAD+) and exist in three distinct isomeric forms. Like the canonical nucleosides, the corresponding pyridone-containing nucleosides (PYR) are chemically stable, biochemically versatile, and easily converted to nucleotides, di- and triphosphates, and dinucleotides. The 4-PYR isomer is often reported with its abundance increasing with the progression of metabolic diseases, age, cancer, and oxidative stress. Yet, the pyridone-derived nucleotides are largely under-represented in the literature. Here, we report the efficient synthesis of the series of ox-NAD and pyridone nucleotides and measure the abundance of ox-NAD in biological specimens using liquid chromatography coupled with mass spectrometry (LC-MS). Overall, we demonstrate that all three forms of PYR and ox-NAD are found in biospecimens at concentrations ranging from nanomolar to midmicromolar and that their presence affects the measurements of NAD(H) concentrations when standard biochemical redox-based assays are applied. Furthermore, we used liver extracts and 1H NMR spectrometry to demonstrate that each ox-NAD isomer can be metabolized to its respective PYR isomer. Together, these results suggest a need for a better understanding of ox-NAD in the context of human physiology since these species are endogenous mimics of NAD+, the key redox cofactor in metabolism and bioenergetics maintenance.

Comparison between ammonium formate and ammonium fluoride in the analysis of stratum corneum lipids by reversed phase chromatography coupled with high resolution mass spectrometry

Lipids are key constituents of the barrier function in the human stratum corneum (SC), which is the outermost layer of the epidermis and amenable to non-invasive sampling by tape stripping. The three major lipid classes in the SC, i.e., ceramides, fatty acids, and cholesterol, present equimolar concentration. Liquid chromatography coupled with mass spectrometry (LCMS) is elective in profiling lipids in the SC in both positive and negative ion modes. Nevertheless, the latter one allows for the simultaneous detection of the three major epidermal components of the SC. Determination of ceramides in the SC poses analytical challenges due to their wide range of structures and concentrations especially in the case of limited sample amounts. Ammonium formate is a commonly used modifier added to the mobile phase to assist ionization. However, it introduces uncertainty in the identification of ceramides when operating in negative ion mode, even with high resolution MS. We tested the advantages of using fluoride in the lipid profiling of SC and unambiguous identification of ceramides subclasses. The use of fluoride enhanced the ionization of ceramides, regardless the specific substructure, solved misidentification issues, and was successfully applied to the simultaneous detection of all three lipid classes in the human SC.

Deep Learning-Assisted Analysis of Immunopeptidomics Data.

Liquid chromatography-coupled mass spectrometry (LC-MS/MS) is the primary method to obtain direct evidence for the presentation of disease- or patient-specific human leukocyte antigen (HLA). However, compared to the analysis of tryptic peptides in proteomics, the analysis of HLA peptides still poses computational and statistical challenges. Recently, fragment ion intensity-based matching scores assessing the similarity between predicted and observed spectra were shown to substantially increase the number of confidently identified peptides, particularly in use cases where non-tryptic peptides are analyzed. In this chapter, we describe in detail three procedures on how to benefit from state-of-the-art deep learning models to analyze and validate single spectra, single measurements, and multiple measurements in mass spectrometry-based immunopeptidomics. For this, we explain how to use the Universal Spectrum Explorer (USE), online Oktoberfest, and offline Oktoberfest. For intensity-based scoring, Oktoberfest uses fragment ion intensity and retention time predictions from the deep learning framework Prosit, a deep neural network trained on a very large number of synthetic peptides and tandem mass spectra generated within the ProteomeTools project. The examples shown highlight how deep learning-assisted analysis can increase the number of identified HLA peptides, facilitate the discovery of confidently identified neo-epitopes, or provide assistance in the assessment of the presence of cryptic peptides, such as spliced peptides.

MRNA-miRNA analyses reveal the involvement of CsbHLH1 and miR1446 in the regulation of caffeine biosynthesis in Camellia sinensis

Abstract Caffeine, a primary flavor component in tea, has been the subject of intense research. With the goal of shedding light on the complex regulatory processes governing caffeine biosynthesis in tea plants, the liquid chromatography coupled with mass spectrometry (LC-MS), transcriptomics, and small RNA analyses were employed on diverse tea cultivars such as ‘Jianghua Kucha’ (including ‘Xianghong 3’ (XH3H) and ‘Kucha 3’ (KC3H)), ‘Fuding Dabaicha’ (FDDB), ‘Yaoshan Xiulv’ (YSXL), and ‘Bixiangzao’ (BXZ). The results showed that the caffeine level in ‘Jianghua Kucha’ was significantly higher than that in other tea plant cultivars. In addition, weighted gene co-expression network analysis (WGCNA) indicated that that the CsbHLH1 gene might play a pivotal role as a potential hub gene related to the regulation of caffeine biosynthesis. Subcellular localization analysis showed that the CsbHLH1 protein was localized in the nucleus of the cells. Moreover, CsbHLH1 suppresses the transcription of TCS1 through binding to the TCS1 promoter, as evidenced by a yeast one-hybrid assay, and an electrophoretic mobility shift assay (EMSA) assay and dual luciferase analysis. In addition, a microRNA, miR1446a, was identified that directly cleaves the downstream transcription factor CsbHLH1 at position 88 bp, leading to an increase in caffeine levels. Therefore, our findings imply that CsbHLH1 binds to the TCS1 promoter (-971 bp to -1019 bp) to reduce its expression, thereby negatively regulating caffeine biosynthesis. On the other hand, miR1446a enhances the biosynthesis of caffeine by suppressing the expression of CsbHLH1. These works enhanced our understanding of the molecular mechanisms of caffeine biosynthesis in tea plants and offered potential directions for manipulating caffeine levels in future tea cultivation.

Degradation of imidacloprid in water by photo-Fenton process using UV-LED lamps at neutral pH: Study of intermediate products by liquid chromatography mass spectrometry after dispersive liquid–liquid microextraction

In the present study, a suitable analytical method to determine imidacloprid (IMI) and its main transformation products (TPs) in water by means of dispersive liquid–liquid microextraction (DLLME) combined with liquid chromatography coupled to mass spectrometry (LC-MS), using both quadrupole-time-of-flight (QTOF) and triple quadrupole (QqQ) analysers, has been developed. In addition, the structures of major products formed when IMI is photo-oxidized using ultraviolet A (UVA) irradiation with light emitting diode (LED) lamps were established. Finally, the behaviour of IMI and its main TPs generated in water during photo-Fenton processes at neutral pH using two ferric iron complexes, with ethylenediamine-N,N-disuccinic acid (EDDS) and nitrilotriacetic acid (NTA) as chelating agents, was studied. DLLME was found to efficiently preconcentrate IMI and IMI TPs from the water matrix using chloroform (as extractant solvent) and acetonitrile (as dispersant solvent) in a simple step. The selectivity of the used techniques provided unequivocal identification of IMI and its TPs and their quantification with high sensitivity during the photo-Fenton treatments. In addition, the photo-Fenton treatment using EDDS exhibited higher degradation rate than photo-Fenton treatment using NTA.

Characterization of the Metabolic Profile of Olive Tissues (Roots, Stems and Leaves): Relationship with Cultivars' Resistance/Susceptibility to the Soil Fungus Verticillium dahliae.

Verticillium wilt of olive (VWO) is one of the most widespread and devastating olive diseases in the world. Harnessing host resistance to the causative agent is considered one of the most important measures within an integrated control strategy of the disease. Aiming to understand the mechanisms underlying olive resistance to VWO, the metabolic profiles of olive leaves, stems and roots from 10 different cultivars with varying levels of susceptibility to this disease were investigated by liquid chromatography coupled to mass spectrometry (LC-MS). The distribution of 56 metabolites among the three olive tissues was quantitatively assessed and the possible relationship between the tissues' metabolic profiles and resistance to VWO was evaluated by applying unsupervised and supervised multivariate analysis. Principal component analysis (PCA) was used to explore the data, and separate clustering of highly resistant and extremely susceptible cultivars was observed. Moreover, partial least squares discriminant analysis (PLS-DA) models were built to differentiate samples of highly resistant, intermediate susceptible/resistant, and extremely susceptible cultivars. Root models showed the lowest classification capability, but metabolites from leaf and stem were able to satisfactorily discriminate samples according to the level of susceptibility. Some typical compositional patterns of highly resistant and extremely susceptible cultivars were described, and some potential resistance/susceptibility metabolic markers were pointed out.

Magnetic Co-doped 1D/2D structured γ-Fe2O3/MoS2 effectively activated peroxymonosulfate for efficient abatement of bisphenol A via both radical and non-radical pathways

Iron-based catalysts have been widely used to treat refractory organic pollutants in wastewater. In this paper, magnetic Co-γ-Fe2O3 was synthesized by a facile tartaric acid-assisted hydrothermal method, and Co-γ-Fe2O3/MoS2 nanocomposite catalyst was obtained via in situ growth of MoS2 nanosheets on Co-γ-Fe2O3 nanoparticles. The nanocomposite catalysts were used to decompose bisphenol A (BPA) by activating peroxymonosulfate (PMS). It was shown that only 0.15 g/L catalyst and 0.5 mmol/L PMS degraded 10 mg/L of BPA (99.3% within 10 min) in the pH range of 3–9. PMS was activated due to redox cycling among the pairs Co(III)/Co(II), Fe(III)/Fe(II), and Mo(VI)/Mo(IV). Quenching experiments and electron paramagnetic resonance spectroscopy demonstrated that both radical and non-radical pathways were involved in BPA degradation, in which active radical sulfate radical and non-radical singlet oxygen were the main reactive oxygen species. Ten intermediates were identified by liquid chromatography-coupled mass spectrometry, and three possible BPA degradation pathways were proposed. The toxicity of several degradation intermediates was lower, and Co-γ-Fe2O3/MoS2 exhibited excellent reusability and could be magnetically recovered.

Abstract A104: ADAR1-associated metabolic vulnerabilities in triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC), lacking expression of estrogen, progesterone, and HER2 receptors, is aggressive and lacks targeted treatment options. Therefore, the mission to identify actionable targets remains the top priority. We recently demonstrated that an RNA editing enzyme, adenosine deaminase acting on RNA 1 (ADAR1), plays important roles in TNBC’s ability to initiate and maintain tumorigenesis. We posit that ADAR1 functions as a homeostatic factor protecting TNBC from stresses when otherwise kept in check, contributing to tumorigenesis. By both targeted and unbiased approaches, we identified two metabolic vulnerabilities, 1) iron-dependent cell death pathway, ferroptosis, and 2) serine addiction, associated with ADAR1 in TNBC. By performing single-reaction monitoring-based liquid chromatography coupled to mass spectrometry (LC-MS) to measure intracellular lipid contents, we showed that ADAR1 loss in TNBC cells increased the abundance of polyunsaturated fatty acid phospholipids (PUFA-PL), of which peroxidation is the primary driver of ferroptosis. Transcriptomic analysis and phenotypic drug screen using a ferroptosis-focused library were performed to identify underlying mechanisms and drug candidates synergizing with ADAR1 loss through ferroptosis, respectively. Meanwhile, an unbiased screen using a FDA-approved compound library revealed that ADAR1 loss also sensitizes TNBC cell line MDA-MB231 to inhibition of the serine biosynthesis pathway. We showed that ADAR1 knockdown leads to altered serine transport, and a metabolic flux analysis using labeled (U-13C) glucose will be performed to determine if ADAR1 loss affects de novo serine biosynthesis and one-carbon metabolism. By testing the hypothesis that ADAR1 regulates the metabolic fitness of TNBC by desensitizing ferroptosis and serine addiction, we aim to leverage these metabolic vulnerabilities to inform basic, pre-clinical, and clinical studies to develop novel therapeutic strategies for TNBC. Citation Format: Che-Pei Kung, Leah P Shriver, Nick Terzich, Ma Xenia G Ilagen, Mike Prinsen, Sua Ryu, Raleigh D Kladney, Gary J Patti, Leonard B Maggi, Jason D Weber. ADAR1-associated metabolic vulnerabilities in triple-negative breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A104.

Improved Glycerol Electrooxidation at Carbon-Supported PdFe Bimetallic Catalysts

We have investigated glycerol electrooxidation at Pd/C and PdFe/C catalysts, synthesized by the microwave polyol decomposition method. Five different heating ramps were tested to provide active catalyst nanoparticles and desired metal loadings at 20 wt%. Introducing iron in the Pd/C catalyst composition improved the catalytic activity and stability of the anode. The PdFe/C catalysts presented greater oxidative capacity and contributed efficiently to the keeping of glycerol skeleton reaction products. The analytical techniques composed of liquid chromatography coupled with mass spectrometry (LC-MS) confirmed glycerate, glycolate, formate, tartronate, and oxalate as the main glycerol oxidation products. The bi-metallic catalysts (PdFe/C) harvested electrons from glycerol and produced energy more effectively than the catalyst without iron (Pd/C). Glycerol proved a potential platform for generating high value-added products and can be employed as a renewable clean energy source for electrosynthesis purposes and fuel cell applications.