Pyrimidine Biosynthesis Research Articles

USE OF THE DISEASE-MODIFYING DRUG LEFLUNOMIDE IN PATIENTS WITH RHEUMATOID ARTHRITIS

This paper is dedicated to an urgent problem of modern medicine, namely the treatment of rheumatoid arthritis. According to the literature, the activation and proliferation of the T-cell and macrophage pool with the involvement of synoviocytes/chondrocytes plays an important role in the pathoge. It is known that the mechanism of action of the active metabolite leflunomide (A771726) blocks dihydroorotate dehydrogenase, which in turn inhibits pyrimidine synthesis in rapidly dividing cells (activated T-lymphocytes, macrophages). As a result, leflunomide blocks the main link in the pathogenetic mechanism of rheumatoid arthritis development and progression.nesis of rheumatoid arthritis, which in turn leads to the destruction of articular cartilage. The study involved 52 patients with rheumatoid arthritis. This group of patients was represented predominantly by women (46 patients); the majority were seropositive for rheumatoid factor (RF) – (42 patients). The drug was prescribed according to the standard scheme: 100 mg/day for the first 3 days, then 20 mg/day. The dose was temporarily reduced in some patients to 10 mg/day in case of intolerance reactions. The effectiveness of leflunomide was evaluated in relation to the effect on indicators of RA activity and progression. In 30% of patients, the duration of rheumatoid arthritis at the time of leflunomide prescription was less than 3 years, in 46% – 4–10 years, and in 24% – more than ten years. Radiological stages III–IV were recorded in 70% of patients. With the exception of 2 patients with rheumatoid arthritis activity of grade II–III, and according to the criteria of the European Anti-Rheumatic League using the Disease activity score (DAS), all patients had moderate to high RA activity. In 35 patients (70%), arthritic manifestations were detected before the start of therapy. The rapid effect of action of Leflunomide is certain with the reliable decline of indexes of arthritis syndrome and laboratory indexes of activity of inflammation in 1 month of treatment.

Plasmodium falciparum Mitochondrial Complex III, the Target of Atovaquone, Is Essential for Progression to the Transmissible Sexual Stages.

The Plasmodium falciparum mitochondrial electron transport chain (mETC) is responsible for essential metabolic pathways such as de novo pyrimidine synthesis and ATP synthesis. The mETC complex III (cytochrome bc1 complex) is responsible for transferring electrons from ubiquinol to cytochrome c and generating a proton gradient across the inner mitochondrial membrane, which is necessary for the function of ATP synthase. Recent studies have revealed that the composition of Plasmodium falciparum complex III (PfCIII) is divergent from humans, highlighting its suitability as a target for specific inhibition. Indeed, PfCIII is the target of the clinically used anti-malarial atovaquone and of several inhibitors undergoing pre-clinical trials, yet its role in parasite biology has not been thoroughly studied. We provide evidence that the universally conserved subunit, PfRieske, and the new parasite subunit, PfC3AP2, are part of PfCIII, with the latter providing support for the prediction of its divergent composition. Using inducible depletion, we show that PfRieske, and therefore, PfCIII as a whole, is essential for asexual blood stage parasite survival, in line with previous observations. We further found that depletion of PfRieske results in gametocyte maturation defects. These phenotypes are linked to defects in mitochondrial functions upon PfRieske depletion, including increased sensitivity to mETC inhibitors in asexual stages and decreased cristae abundance alongside abnormal mitochondrial morphology in gametocytes. This is the first study that explores the direct role of the PfCIII in gametogenesis via genetic disruption, paving the way for a better understanding of the role of mETC in the complex life cycle of these important parasites and providing further support for the focus of antimalarial drug development on this pathway.

Non-Targeted Metabolomics Analysis of γ-Aminobutyric Acid Enrichment in Germinated Maize Induced by Pulsed Light.

Pulsed light is an emerging technique in plant physiology recognized for its ability to enhance germination and accumulate γ-aminobutyric acid in maize. Pulsed light involves exposing plants to brief, high-intensity bursts of light, which can enhance photosynthesis, improve growth, and increase resistance to environmental stresses. Despite its promising potential, the specific metabolic changes leading to γ-aminobutyric acid enrichment in maize induced by pulsed light are not fully understood. This study addresses this gap by quantifying key nutrients and γ-aminobutyric acid-related compounds during maize germination and investigating the underlying mechanisms using non-targeted metabolomics. Our findings indicate that pulsed light significantly promotes maize germination and accelerates the hydrolysis of proteins, sugars, and lipids. This acceleration is likely due to the activation of enzymes involved in these metabolic pathways. Additionally, pulsed light markedly increases the content of glutamic acid and the activity of glutamate decarboxylase, which are crucial for γ-aminobutyric acid synthesis. Moreover, pulsed light significantly reduces the activity of γ-aminobutyric transaminase, thereby inhibiting γ-aminobutyric acid decomposition and resulting in a substantial increase in γ-aminobutyric acid content, with a 27.20% increase observed in germinated maize following pulsed light treatment. Metabolomic analysis further revealed enrichment of metabolic pathways associated with γ-aminobutyric acid, including amino acid metabolism, carbohydrate metabolism, plant hormone signal transduction, energy metabolism, pyrimidine metabolism, and ABC transporters. In conclusion, pulsed light is a robust and efficient method for producing sprouted maize with a high γ-aminobutyric acid content. This technique provides a novel approach for developing sprouted cereal foods with enhanced nutritional profiles, leveraging the physiological benefits of γ-aminobutyric acid, which include stress alleviation and potential health benefits for humans.

Enantioselective toxicity effect and mechanisms of bifenthrin enantiomers on normal human hepatocytes

In recent decades, the toxicity of chiral pesticides to non-target organisms has attracted increasing attention. Cellular metabolic disorders are essential sensitive molecular initiating event for toxicological effects. BF is a typical chiral pesticide, and the liver is the main organ for BF accumulation. This study aimed to investigate the potential molecular mechanism of BF enantiomers' different toxic effects on L02 by a non-targeted metabolomic approach. Results revealed that the BF enantiomers exhibited different metabolic responses. In total, 51 and 36 differential metabolites were perturbed by 1S-cis-BF and 1R-cis-BF at the value of variable importance, respectively. When L02 were exposed to 1R-cis-BF, the significantly disturbed metabolic pathways were nicotinate and nicotinamide metabolism and pyrimidine metabolism. By comparison, more significantly perturbed metabolic pathways were received when the L02 were exposed to 1S-cis-BF, including glycine, serine and threonine metabolism, nicotinate and nicotinamide metabolism, arginine and proline metabolism, cysteine and methionine metabolism, glycerolipid metabolism, histidine metabolism, pyrimidine metabolism, amino sugar and nucleotide sugar metabolism and arginine biosynthesis. The results offer a new perspective in understanding the role of selective cytotoxicity of BF enantiomers, and help to evaluate the risk to human health at the enantiomeric level.

UCK2 promotes intrahepatic cholangiocarcinoma progression and desensitizes cisplatin treatment by PI3K/AKT/mTOR/autophagic axis

Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive tumor with extremely poor prognosis due to the low resection rate, high recurrence rate and drug resistance. Uridine-cytidine kinase 2 (UCK2) is proved to promote progression and drug resistance of various carcinomas by regulating pyrimidine metabolism. However, the role of UCK2 in progression and drug resistance of iCCA was largely unclear. Gene expression matrices were obtained from public database and were verified by qRT-PCR using tumor sample from Sun Yat-sen University Cancer Center. Knockdown and overexpression of UCK2 were used to evaluate the effects of UCK2 on carcinogenesis and cisplatin response in iCCA. CCK8-kit assays and plate clone formation assays were performed to detect the effect of UCK2 on proliferative activity of tumor cells. Western blotting was performed to investigate protein level of UCK2 and the relevant biomarkers of PI3K/AKT/mTOR/autophagic axis. Cell migration and invasion were assessed by using wound-healing and transwell assays. UCK2 expression was detected elevated in iCCA tissues compared with adjacent normal tissues. Biologically, overexpression of UCK2 can promote proliferation of iCCA cells, and desensitizes iCCA to cisplatin in both in vivo and in vitro models. Mechanistically, UCK2 promote iCCA progression and cisplatin resistance through inhibition of autophagy by activating the PI3K/AKT/mTOR signaling pathway. Clinically, higher UCK2 expression in iCCA tumor was associated with aggressive tumor features, poorer survival and lower sensitivity of chemotherapy. UCK2 promotes iCCA progression and desensitizes cisplatin treatment by regulating PI3K/AKT/mTOR/autophagic axis. UCK2 exhibited potential as a biomarker in predicting prognosis and drug sensitivity of iCCA patients.

Toxicity of Moxifloxacin on the Growth, Photosynthesis, Antioxidant System, and Metabolism of Microcystis aeruginosa at Different Phosphorus Levels.

Moxifloxacin (MOX), a widely used novel antibiotic, may pose ecological risks at its actual environmental concentrations, as has been detected in aquatic systems. However, its ecotoxicity to aquatic organisms and regulatory mechanisms of phosphorus in eutrophic aqueous environments are still limited. This study aimed to analyze its physiological and biochemical parameters, including cellular growth, chlorophyll fluorescence, photosynthetic pigments, oxidative stress biomarkers, and metabolomics to elucidate the toxicity induced by environmental concentrations of MOX in Microcystis aeruginosa at different phosphorus levels. The results revealed that the EC50 values of MOX on M. aeruginosa at different phosphorus concentrations were 8.03, 7.84, and 6.91 μg/L, respectively, indicating MOX toxicity was exacerbated with increasing phosphorus levels. High phosphorus intensified the suppression of chlorophyll fluorescence and photosynthetic pigments, while activating the antioxidant enzyme, indicating severe peroxidation damage. Metabolomic analysis showed MOX induced different discriminating metabolites under different phosphorus levels, and perturbed more biological pathways at higher phosphorus concentrations, such as starch and sucrose metabolism, pyrimidine metabolism, and glycerolipid metabolism. This indicates that phosphorus plays an important role in regulating metabolism in M. aeruginosa exposed to MOX. The findings provide valuable information on the mechanisms involved in cyanobacteria responses to antibiotic stress, and offer a theoretical basis for accurately assessing antibiotic toxicity in eutrophic aqueous environments.

MicroRNAs Participate in Morphological Acclimation of Sugar Beet Roots to Nitrogen Deficiency.

Nitrogen (N) is essential for sugar beet (Beta vulgaris L.), a highly N-demanding sugar crop. This study investigated the morphological, subcellular, and microRNA-regulated responses of sugar beet roots to low N (LN) stress (0.5 mmol/L N) to better understand the N perception, uptake, and utilization in this species. The results showed that LN led to decreased dry weight of roots, N accumulation, and N dry matter production efficiency, along with damage to cell walls and membranes and a reduction in organelle numbers (particularly mitochondria). Meanwhile, there was an increase in root length (7.2%) and branch numbers (29.2%) and a decrease in root surface area (6.14%) and root volume (6.23%) in sugar beet after 7 d of LN exposure compared to the control (5 mmol/L N). Transcriptomics analysis was confirmed by qRT-PCR for 6 randomly selected microRNAs, and we identified 22 differentially expressed microRNAs (DEMs) in beet root under LN treatment. They were primarily enriched in functions related to binding (1125), ion binding (641), intracellular (437) and intracellular parts (428), and organelles (350) and associated with starch and sucrose metabolism, tyrosine metabolism, pyrimidine metabolism, amino sugar and nucleotide sugar metabolism, and isoquinoline alkaloid biosynthesis, as indicated by the GO and KEGG analyses. Among them, the upregulated miR156a, with conserved sequences, was identified as a key DEM that potentially targets and regulates squamosa promoter-binding-like proteins (SPLs, 104889216 and 104897537) through the microRNA-mRNA network. Overexpression of miR156a (MIR) promoted root growth in transgenic Arabidopsis, increasing the length, surface area, and volume. In contrast, silencing miR156a (STTM) had the opposite effect. Notably, the fresh root weight decreased by 45.6% in STTM lines, while it increased by 27.4% in MIR lines, compared to the wild type (WT). It can be inferred that microRNAs, especially miR156, play crucial roles in sugar beet root's development and acclimation to LN conditions. They likely facilitate active responses to N deficiency through network regulation, enabling beet roots to take up nutrients from the environment and sustain their vital life processes.

Capecitabine mitigates cardiac allograft rejection via inhibition of TYMS-Mediated Th1 differentiation in mice

ObjectivesPrevious studies elucidated that capecitabine (CAP) works as an anti-tumor agent with putative immunosuppressive effects. However, the intricate mechanisms underpinning these effects remain to be elucidated. In this study, we aimed to unravel the molecular pathways by which CAP exerts its immunosuppressive effects to reduce allograft rejection. MethodsHearts were transplanted from male BALB/c donors to male C57BL/6 recipients and treated with CAP for seven days. The rejection of these heart transplants was assessed using a range of techniques, including H&E staining, immunohistochemistry, RNA sequencing, LS-MS/MS, and flow cytometry. In vitro, naïve CD4+ T cells were isolated and cultured under Th1 condition medium with varying treatments, flow cytometry, LS-MS/MS were employed to delineate the role of thymidine synthase (TYMS) during Th1 differentiation. ResultsCAP treatment significantly mitigated acute allograft rejection and enhanced graft survival by reducing graft damage, T cell infiltration, and levels of circulating pro-inflammatory cytokines. Additionally, it curtailed CD4+ T cell proliferation and the presence of Th1 cells in the spleen. RNA-seq showed that TYMS, the target of CAP, was robustly increased post-transplantation in splenocytes. In vitro, TYMS and its metabolic product dTMP were differentially expressed in Th0 and Th1, and were required after activation of CD4+ T cell and Th1 differentiation. TYMS-specific inhibitor, raltitrexed, and the metabolite of capecitabine, 5-fluorouracil, could inhibit the proliferation and differentiation of Th1. Finally, the combined use of CAP and the commonly used immunosuppressant rapamycin can induce long-term survival of allograft. ConclusionCAP undergoes metabolism conversion to interfere pyrimidine metabolism, which targets TYMS-mediated differentiation of Th1, thereby playing a significant role in mitigating acute cardiac allograft rejection in murine models.

Baseline Gut Microbiota Was Associated with Long-Term Immune Response at One Year Following Three Doses of BNT162b2.

This study explored neutralizing IgG antibody levels against COVID-19 decline over time post-vaccination. We conducted this prospective cohort study to investigate the function of gut microbiota in the host immune response following three doses of BNT162b2. Subjects who received three doses of BNT162b2 were recruited from three centers in Hong Kong. Blood samples were obtained before the first dose and at the one-year timepoint for IgG ELISA to determine the level of neutralizing antibody (NAb). The primary outcome was a high immune response (NAb > 600 AU/mL). We performed shotgun DNA metagenomic sequencing on baseline fecal samples to identify bacterial species and metabolic pathways associated with high immune response using linear discriminant analysis effect size analysis. A total of 125 subjects were recruited (median age: 52 years [IQR: 46.2-59.0]; male: 43 [34.4%]), and 20 were regarded as low responders at the one-year timepoint. Streptococcus parasanguinis (log10LDA score = 2.38, p = 0.003; relative abundance of 2.97 × 10-5 vs. 0.03%, p = 0.001), Bacteroides stercoris (log10LDA score = 4.29, p = 0.024; relative abundance of 0.14% vs. 2.40%, p = 0.014) and Haemophilus parainfluenzae (log10LDA score = 2.15, p = 0.022; relative abundance of 0.01% vs. 0, p = 0.010) were enriched in low responders. Bifidobacterium pseudocatenulatum (log10LDA score = 2.99, p = 0.048; relative abundance of 0.09% vs. 0.36%, p = 0.049) and Clostridium leptum (log10LDA score = 2.38, p = 0.014; relative abundance of 1.2 × 10-5% vs. 0, p = 0.044) were enriched in high responders. S. parasanguinis was negatively correlated with the superpathway of pyrimidine ribonucleotides de novo biosynthesis (log10LDA score = 2.63), which contributes to inflammation and antibody production. H. parainfluenzae was positively correlated with pathways related to anti-inflammatory processes, including the superpathway of histidine, purine, and pyrimidine biosynthesis (log10LDA score = 2.14). Among three-dose BNT162b2 recipients, S. parasanguinis, B. stercoris and H. parainfluenzae were associated with poorer immunogenicity at one year, while B. pseudocatenulatum and C. leptum was associated with a better response.

A proteomics and transcriptome analysis provides insight into the molecular mechanisms of tea tree oil against Aeromonas hydrophila

Aeromonas hydrophila is a widespread fish pathogen. However, due to the extensive use of antibiotics in aquaculture, this bacterium has developed drug resistance. In recent years, tea tree oil, extracted from Melaleuca alternifolia, has gained widespread application in antibacterial research. Nevertheless, the underlying mechanism of action of tea tree oil on A. hydrophila remains unclear. In this study, the inhibitory effect of tea tree oil on A. hydrophila was analyzed, and its mechanism of action was elucidated through a combination of transcriptome and proteome analyses. In the current work, tea tree oil (0.039 mg/mL) significantly inhibited the growth of A. hydrophila and changed the permeability of the cell membrane. A total of 109 differentially expressed genes (DEGs) were identified by the combined analysis of the transcriptome and the proteome, of which 46 were upregulated and 63 were downregulated. These co-regulated DEGs were primarily enriched in metabolic pathways such as bacterial chemotaxis, pyrimidine metabolism, and the two-component system. Simultaneously, it was found that the target proteins of tea tree oil, such as secB, yajC, rpsP, rplL, and rpsT were significantly downregulated. These findings suggested that the potential of tea tree oil as an alternative to antibiotics in inhibiting the growth of A. hydrophila. It provides new insights into the molecular mechanisms underlying the antimicrobial activity of tea tree oil against A. hydrophila.

Polysaccharides from Alpinia oxyphylla fruit prevent hyperuricemia by inhibiting uric acid synthesis, modulating intestinal flora and reducing renal inflammation

Hyperuricemia (HUA) is one of the most common chronic diseases today, with a prevalence exceeding 14 % in both the United States and China. Current clinical treatments for HUA focus on promoting uric acid (UA) excretion and inhibiting UA production, but often neglect the strain on the liver and kidneys. The fruit of Alpinia oxyphylla (A. oxyphylla) is known to improve renal function, regulate metabolism, and exhibit anti-inflammatory effects; however, its effectiveness and mechanisms in treating HUA are not well understood. In this study, HUA mice induced by potassium oxonate and adenine were treated with A. oxyphylla polysaccharide (AFP) for 21 days. The levels associated with HUA were quantified using assay kits to evaluate the impact of AFP on HUA. Serum metabolomics and 16S rRNA sequencing were used to investigate the mechanisms by which AFP ameliorates HUA. The results showed that AFP treatment reduced abnormal biochemical levels, including UA, blood urea nitrogen, and creatinine, in HUA mice. AFP inhibited UA synthesis by regulating pyrimidine metabolism and the metabolism of alanine, aspartate and glutamate, reduced kidney inflammation, and promoted UA excretion by regulating intestinal flora. Thus, AFP appears to be an effective agent for alleviating HUA symptoms.

Co-exposure effect of different colour of LED lights and increasing temperature on zebrafish larvae (Danio rerio): Immunohistochemical, metabolomics, molecular and behaviour approaches

Although there are studies in the literature on the effects of different coloured light-emitting diodes (LEDs) on different organisms, there is limited information on how these effects change with temperature increase. In this study, the effects of blue, green, red and white LED lights on the early development process of zebrafish (Danio rerio (Hamilton, 1822)) were comprehensively investigated. In addition, to simulate global warming, it was examined how a one-degree temperature increase affects this process. For this purpose, zebrafish embryos, which were placed at 4 hpf (hours post fertilization) in an incubator whose interior was divided into four areas, were kept at three different temperatures (28, 29 and 30 °C) for 120 h. The group kept in a dark environment was chosen as the control. The temperature of the control group was also increased at the same rate as the other groups. The results showed that at the end of the exposure period, temperature and light colour caused an increase in body malformations. Histopathological damage and immunopositive signals of HSP 70 and 8-OHdG biomarkers in larval brains, increase in free oxygen radicals, apoptotic cells and lipid accumulation throughout the body, increase in locomotor activity, decrease in heart rate and blood flow, and significant changes in more than thirty metabolite levels were detected. In addition, it has been determined that many metabolic pathways are affected, especially glutathione, vitamin B6 and pyrimidine metabolism. Moreover, it has been observed that a one-degree temperature increase worsens this negative effect. It was concluded that blue light was the closest light to the control group and was less harmful than other light colours. The study revealed that blue light produced results that were most similar to those seen in the control group.

The integrated analysis of gut microbiota and metabolome revealed steroid hormone biosynthesis is a critical pathway in liver regeneration after 2/3 partial hepatectomy.

Introduction: The liver is the only organ capable of full regeneration in mammals. However, the exact mechanism of gut microbiota and metabolites derived from them relating to liver regeneration has not been fully elucidated. Methods: To demonstrate how the gut-liver axis contributes to liver regeneration, using an LC-QTOF/MS-based metabolomics technique, we examine the gut microbiota-derived metabolites in the gut content of C57BL/6J mice at various points after 2/3 partial hepatectomy (PHx). Compound identification, multivariate/univariate data analysis and pathway analysis were performed subsequently. The diversity of the bacterial communities in the gastrointestinal content was measured using 16S rRNA gene sequencing. Then, the integration analysis of gut microbiota and metabolome was performed. Results: After 2/3 PHx, the residual liver proliferated quickly in the first 3days and had about 90% of its initial weight by the seventh day. The results of PLS-DA showed that a significant metabolic shift occurred at 6h and 36h after 2/3 PHx that was reversed at the late phase of liver regeneration. The α and β-diversity of the gut microbiota significantly changed at the early stage of liver regeneration. Specifically, Escherichia Shigella, Lactobacillus, Akkermansia, and Muribaculaceae were the bacteria that changed the most considerably during liver regeneration. Further pathway analysis found the most influenced co-metabolized pathways between the host and gut bacteria including glycolysis, the TCA cycle, arginine metabolism, glutathione metabolism, tryptophan metabolism, and purine and pyrimidine metabolism. Specifically, steroid hormone biosynthesis is the most significant pathway of the host during liver regeneration. Discussion: These findings revealed that during liver regeneration, there was a broad modification of gut microbiota and systemic metabolism and they were strongly correlated. Targeting specific gut bacterial strains, especially increasing the abundance of Akkermansia and decreasing the abundance of Enterobacteriaceae, may be a promising beneficial strategy to modulate systemic metabolism such as amino acid and nucleotide metabolism and promote liver regeneration.

An untargeted comparative metabolomics analysis of infants with and without late-onset breast milk jaundice.

Late-onset breast milk jaundice (LBMJ) is a common form of hyperbilirubinemia, which can result in serious complications for newborns with persistently high bilirubin levels. The aim of this study was to investigate the differences in fecal metabolites between breastfed infants with and without LBMJ in order to elucidate potential biological mechanisms. Biological samples were collected from 12 infants with LBMJ and 12 healthy individuals. Ultra-high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS) was utilized for non-targeted determination of fecal metabolites. Principal components analysis (PCA), cluster analysis, and differential metabolite analysis were performed in both positive ion mode and negative ion mode for the two groups. Additionally, the KEGG database was employed to comprehensively analyze the pathways of differential metabolites. There were no significant differences in maternal and neonatal demographic characteristics between the two groups (p > 0.05). The results of PCA and cluster heat map analysis in both modes showed that there were significant differences in metabolites between the two groups. Among 751 differential metabolites (DMs) detected in positive ion mode, 720 were up-regulated in the case group while 31 were down-regulated. In negative ion mode, 1891 DMs were detected, including 817 up-regulated metabolites and 1074 down-regulated metabolites in the case group. Analysis of differential metabolic pathways showed that the DMs of the two groups were mainly annotated and enriched in Biotin metabolism, N-Glycan biosynthesis, Taurine and hypotaurine metabolism, Pyrimidine metabolism, and Pentose and glucuronate interconversions. Significant differences exist in fecal metabolites between LBMJ infants and healthy controls. The study of differential metabolic pathways provides insights into the mechanism of LBMJ.

DHA-enriched phosphatidylserine ameliorates cyclophosphamide-induced liver injury via regulating the gut-liver axis

ObjectiveThis study explores the therapeutic effects and mechanisms of DHA-enriched phosphatidylserine (DHA-PS) on liver injury induced by cyclophosphamide (CTX) in mice, focusing on the gut-liver axis. MethodsA mouse model was established by administering CTX (80 mg/kg) intraperitoneally for 5 days. DHA-PS (50 or 100 mg/kg) was administered for the next 7 days to assess its reparative impact on liver damage. ResultsThe findings revealed significant improvements in liver biochemical indices, inflammatory markers, and oxidative stress levels in the mice treated with DHA-PS. Through non-targeted metabolomics analysis, DHA-PS mitigated CTX-induced metabolic disruptions by modulating lipid, amino acid, and pyrimidine metabolism. Immunofluorescence analysis further confirmed that DHA-PS reduced the expression of liver-associated inflammatory proteins by inhibiting the TLR4/NF-κB pathway. Additionally, DHA-PS restored the intestinal barrier, evidenced by adjustments in the levels of intestinal lipopolysaccharide (LPS), secretory immunoglobulin A (sIgA), and tight junction proteins (Claudin-1, Occludin, and ZO-1). It also improved gut microbiota balance by enhancing microbial diversity, increasing beneficial bacteria, and altering community structures. ConclusionThese results suggest that DHA-PS could be a potential therapeutic agent or functional food for CTX-induced liver injury through its regulation of the gut-liver axis.

Host-microbe interactions rewire metabolism in a C. elegans model of leucine breakdown deficiency.

In humans, defects in leucine catabolism cause a variety of inborn errors in metabolism. Here, we use Caenorhabditis elegans to investigate the impact of mutations in mccc-1, an enzyme that functions in leucine breakdown. Through untargeted metabolomic and transcriptomic analyses we find extensive metabolic rewiring that helps to detoxify leucine breakdown intermediates via conversion into previously undescribed metabolites and to synthesize mevalonate, an essential metabolite. We also find that the leucine breakdown product 3,3-hydroxymethylbutyrate (HMB), commonly used as a human muscle-building supplement, is toxic to C. elegans and that bacteria modulate this toxicity. Unbiased genetic screens revealed interactions between the host and microbe, where components of bacterial pyrimidine biosynthesis mitigate HMB toxicity. Finally, upregulated ketone body metabolism genes in mccc-1 mutants provide an alternative route for biosynthesis of the mevalonate precursor 3-hydroxy-3-methylglutaryl-CoA. Our work demonstrates that a complex host-bacteria interplay rewires metabolism to allow host survival when leucine catabolism is perturbed.

Integrated Analyses of Metabolome and RNA-seq Data Revealing Flower Color Variation in Ornamental Rhododendron simsii Planchon.

Rhododendron simsii Planchon is an important ornamental species in the northern hemisphere. Flower color is an important objective of Rhododendron breeding programs. However, information on anthocyanin synthesis in R. simsii is limited. In this research, the regulatory mechanism of anthocyanin biosynthesis in R. simsii was performed through the integrated analysis of metabolome and RNA-seq. A total of 805 and 513 metabolites were screened by positive and negative ionization modes, respectively, In total, 79 flavonoids contained seven anthocyanidins, 42 flavanones, 10 flavans, 13 flavones, and seven flavonols. Methylated and glycosylated derivatives took up the most. Differentially accumulated metabolites were mainly involved in "flavone and flavonol biosynthesis", "cyanoamino acid metabolism", "pyrimidine metabolism", and "phenylalanine metabolism" pathways. For flavonoid biosynthesis, different expression of shikimate O-hydroxycinnamoyltransferase, caffeoyl-CoA O-methyltransferase, flavonoid 3'-monooxygenase, flavonol synthase, dihydroflavonol 4-reductase/flavanone 4-reductase, F3'5'H, chalcone synthase, leucoanthocyanidin reductase, and 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase genes ultimately led to different accumulations of quercetin, myricetin, cyanidin, and eriodictyol. In flavone and flavonol biosynthesis pathway, differential expression of F3'5'H, flavonoid 3'-monooxygenase and flavonol-3-O-glucoside/galactoside glucosyltransferase genes led to the differential accumulation of quercetin, isovitexin, and laricitrin. This research will provide a biochemical basis for further modification of flower color and genetic breeding in R. simsii and related Rhododendron species.

Saliva, Plasma, and Multifluid Metabolomic Signatures of Periodontal Disease, Type 2 Diabetes Progression, and Markers of Glycemia and Dyslipidemia Among Puerto Rican Adults With Overweight and Obesity.

Evidence from cohort studies indicates a bidirectional relationship between periodontal disease and type 2 diabetes (T2D), but the underlying mechanisms remain unknown. In this study, we aimed to (1) identify saliva, plasma, and multifluid metabolomic signatures associated with periodontal disease and (2) determine if these signatures predict T2D progression and cardiometabolic biomarkers at year 3. We included participants from the SOALS (San Juan Overweight Adult Longitudinal Study) (n=911). Metabolites from saliva (k=635) and plasma (k=1051) were quantified using liquid chromatography-mass spectrometry. We applied elastic net regression with 10-fold cross-validation to identify baseline metabolomic signatures of periodontal disease. Multivariable Cox proportional hazards regression and linear regression were used to evaluate the association with T2D progression and biomarker concentrations. Metabolomic profilesincluded highly weighted metabolites related to lysine and pyrimidine metabolism. Periodontal disease or its 3 metabolomic signatures were not associated with T2D progression in 3 years. Prospectively, 1-SD increments in the multifluid and saliva metabolomic signatures were associated with higher low-density lipoprotein (multifluid: 12.9±5.70, P=0.02; saliva: 13.3±5.11, P=0.009). A 1-SD increment in the plasma metabolomic signature was also associated with Homeostatic Model Assessment for Insulin Resistance (2.67±1.14, P=0.02) and triglyceride (0.52±0.18, P=0.002). Although metabolomic signatures of periodontal disease could not predict T2D progression, they were associated with low-density lipoprotein, triglyceride, and Homeostatic Model Assessment for Insulin Resistance levels at year 3.

Synthesis and Characterization of DHODH Inhibitors Based on the Vidofludimus Scaffold with Pronounced Anti-SARS-CoV-2 Activity.

New strategies for the rapid development of broad-spectrum antiviral therapies are urgently required for emerging and re-emerging viruses like the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Host-directed antivirals that target universal cellular metabolic pathways necessary for viral replication present a promising approach with broad-spectrum activity and low potential for development of viral resistance. Dihydroorotate dehydrogenase (DHODH) was identified as one of those universal host factors essential for the replication of many clinically relevant human pathogenic viruses. DHODH is the rate-limiting enzyme catalyzing the fourth step in the de novo pyrimidine synthesis. Therefore, it is also developed as a therapeutic target for many diseases relying on cellular pyrimidine resources, such as cancer, autoimmune diseases and viral or bacterial infection. Thus, several DHODH inhibitors, including vidofludimus calcium (VidoCa, IMU-838), are currently in development or have been investigated in clinical trials for the treatment of virus infections such as SARS-CoV-2-mediated coronavirus disease 19 (COVID-19). Here, we report the medicinal chemistry optimization of VidoCa that resulted in metabolically more stable derivatives with improved DHODH target inhibition in various mammalian species, which translated into improved efficacy against SARS-CoV-2.

Comprehensive analysis of flavor compounds and metabolites of vinasse hairtail fermentation based on GC-IMS and untargeted-based metabolomics

This study focused on investigating the degradation of proteins, metabolites, and flavors during the fermentation of vinasse hairtail, a local specialty fermented food in Zhoushan, China. The whole-protein SDS-PAGE results showed significant degradation of proteins, particularly actin and myosin. Total free amino acid content significantly increased, glutamate, leucine, alanine, and lysine were identified as the primary flavor amino acids conducive to the flavor, with umami, sweet, and bitter amino acids being predominant. The volatile constituents of the vinasse hairtail samples collected before fermentation (0 days) and after fermentation (8 days) were examined using gas chromatography-ion mobility spectrometry (GC-IMS). It revealed a total of 83 volatile flavor compounds, with the relative content of esters increasing and alcohols decreasing during fermentation. The untargeted metabolomics analysis identified 395 unique metabolites; the top 100 metabolites exhibited significant differences, including 52 oligopeptides, 18 organic acids and their derivatives, and 12 lipids and lipid molecules. The metabolic pathways involved in N-glycan biosynthesis, taurine and hypotaurine metabolism, pyrimidine metabolism, glycerophospholipid metabolism, alanine, aspartic acid, and glutamic acid metabolism, tricarboxylic acid cycle, and histidine metabolism. These pathways contribute to the generation of amino acids, sugars, organic acids, and other flavor compounds, ultimately influencing the evolution of the flavor of vinasse hairtail.