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Biochemical and Biophysical Research... Jul 2023Uridine has formerly been shown to alleviate obesity and hepatic lipid accumulation. N-carbamoyl aspartate (NCA) provides carbon atoms to uridine in de novo pyrimidine...
Uridine has formerly been shown to alleviate obesity and hepatic lipid accumulation. N-carbamoyl aspartate (NCA) provides carbon atoms to uridine in de novo pyrimidine biosynthesis pathway. However, whether NCA is involved in the lipid metabolism remains elusive. Here we showed that NCA supplementation significantly decreased (P < 0.05) serum cholesterol (CHOL), high-density lipoprotein (HDL), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) levels of mice, and significantly increased (P < 0.05) relative mRNA expression of genes related to the synthesis of pyrimidine nucleotides and polyunsaturated fatty acids. Besides, supplemented with NCA significantly decreased body weight and area under the curve (AUC), and increased body temperature in the high-fat diet fed mice. For further, relative protein expression of uridine monophosphate synthase (UMPS), sterol regulatory element-binding protein 1(SREBP-1) and phosphorylated hormone-sensitive triglyceride lipase (P-HSL) in the liver, and uncoupling protein 1 (UCP-1) in interscapular brown adipose tissue (iBAT) also showed upregulated in the high-fat diet fed mice. Thus, NCA promoted de novo synthesis of pyrimidine and polyunsaturated fatty acid, and reduced body weight by stimulating high-fat diet-induced thermogenesis of iBAT.
Topics: Mice; Animals; Adipose Tissue, Brown; Aspartic Acid; Body Weight; Thermogenesis; Diet, High-Fat; Pyrimidines; Uridine
PubMed: 37163935
DOI: 10.1016/j.bbrc.2023.04.094 -
NPJ Precision Oncology Nov 2023In this study, we investigated the metabolic alterations associated with clinical response to chemotherapy in patients with ovarian cancer. Pre- and post-neoadjuvant...
In this study, we investigated the metabolic alterations associated with clinical response to chemotherapy in patients with ovarian cancer. Pre- and post-neoadjuvant chemotherapy (NACT) tissues from patients with high-grade serous ovarian cancer (HGSC) who had poor response (PR) or excellent response (ER) to NACT were examined. Desorption electrospray ionization mass spectrometry (DESI-MS) was performed on sections of HGSC tissues collected according to a rigorous laparoscopic triage algorithm. Quantitative MS-based proteomics and phosphoproteomics were performed on a subgroup of pre-NACT samples. Highly abundant metabolites in the pre-NACT PR tumors were related to pyrimidine metabolism in the epithelial regions and oxygen-dependent proline hydroxylation of hypoxia-inducible factor alpha in the stromal regions. Metabolites more abundant in the epithelial regions of post-NACT PR tumors were involved in the metabolism of nucleotides, and metabolites more abundant in the stromal regions of post-NACT PR tumors were related to aspartate and asparagine metabolism, phenylalanine and tyrosine metabolism, nucleotide biosynthesis, and the urea cycle. A predictive model built on ions with differential abundances allowed the classification of patients' tumor responses as ER or PR with 75% accuracy (10-fold cross-validation ridge regression model). These findings offer new insights related to differential responses to chemotherapy and could lead to novel actionable targets.
PubMed: 37923835
DOI: 10.1038/s41698-023-00454-0 -
Neuron Jun 2024Microglial calcium signaling is rare in a baseline state but strongly engaged during early epilepsy development. The mechanism(s) governing microglial calcium signaling...
Microglial calcium signaling is rare in a baseline state but strongly engaged during early epilepsy development. The mechanism(s) governing microglial calcium signaling are not known. By developing an in vivo uridine diphosphate (UDP) fluorescent sensor, GRAB, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP can signal through the microglial-enriched P2Y receptor to increase calcium activity during epileptogenesis. P2Y calcium activity is associated with lysosome biogenesis and enhanced production of NF-κB-related cytokines. In the hippocampus, knockout of the P2Y receptor prevents microglia from fully engulfing neurons. Attenuating microglial calcium signaling through calcium extruder ("CalEx") expression recapitulates multiple features of P2Y knockout, including reduced lysosome biogenesis and phagocytic interactions. Ultimately, P2Y knockout mice retain more CA3 neurons and better cognitive task performance during epileptogenesis. Our results demonstrate that P2Y signaling impacts multiple aspects of myeloid cell immune function during epileptogenesis.
Topics: Animals; Microglia; Mice; Phagocytosis; Receptors, Purinergic P2; Mice, Knockout; Calcium Signaling; Epilepsy; Uridine Diphosphate; Lysosomes; Neurons; Mice, Inbred C57BL; Male; Hippocampus; Neuroimmunomodulation
PubMed: 38614103
DOI: 10.1016/j.neuron.2024.03.017 -
Chemico-biological Interactions Aug 2023Tucatinib is known as a tyrosine kinase inhibitor (TKI), which has been commonly approved for the treatment of adult patients with advanced unresectable or metastatic...
Tucatinib is known as a tyrosine kinase inhibitor (TKI), which has been commonly approved for the treatment of adult patients with advanced unresectable or metastatic HER2-positive breast cancer. However, there haven't been systematic study about the inhibition of tucatinib on UDP-Glucuronosyltransferases (UGTs) and the potential risk of drug-drug interactions (DDIs). In present study, we aimed to systematically investigate the inhibition of tucatinib on recombinant human UGTs and pooled human liver microsomes (HLMs), and to quantitatively evaluate its potential risk of DDIs by in vitro-in vivo extrapolation (IVIVE). Our data indicated that tucatinib exhibited extensive inhibition on recombinant UGTs. Tucatinib was a weak inhibitor of UGT1A4, 2B4 and 2B7; tucatinib possessed a strong inhibitory effect on UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2B15 and UGT2B17, with IC values of 0.53 μM-15.50 μM. Especially, it also potently inhibited estradiol and SN-38 glucuronidation in HLMs with IC values of 46.83 μM and 1.33 μM. The quantitative prediction of DDIs risk indicated that the co-administration of tucatinib with drugs mainly metabolized by hepatic or intestinal UGTs (UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2B15 and UGT2B17) might result in potential DDIs risk through inhibition of glucuronidation. More attention should be paid to the influence of tucatinib on UGTs in liver and intestine to avoid unnecessary clinical DDIs risk.
Topics: Humans; Glucuronosyltransferase; Microsomes, Liver; Drug Interactions; Uridine Diphosphate; Kinetics; Glucuronides
PubMed: 37263554
DOI: 10.1016/j.cbi.2023.110574 -
The Lancet. Gastroenterology &... Apr 2024Direct-acting antivirals (DAAs) for hepatitis C virus (HCV) infection have delivered high response rates (>95%) and simplified the management of HCV treatment,... (Review)
Review
Direct-acting antivirals (DAAs) for hepatitis C virus (HCV) infection have delivered high response rates (>95%) and simplified the management of HCV treatment, permitting non-specialists to manage patients without advanced liver disease. We collected and reviewed global data on the registration and reimbursement (government subsidised) of HCV therapies, including restrictions on reimbursement. Primary data collection occurred between Nov 15, 2021, and July 24, 2023, through the assistance of a global network of 166 HCV experts. We retrieved data for 160 (77%) of 209 countries and juristrictions. By mid-2023, 145 (91%) countries had registered at least one of the following DAA therapies: sofosbuvir-velpatasvir, sofosbuvir-velpatasvir-voxilaprevir, glecaprevir-pibrentasvir, sofosbuvir-daclatasvir, or sofosbuvir. 109 (68%) countries reimbursed at least one DAA therapy. Among 102 low-income and middle-income countries (LMICs), 89 (87%) had registered at least one HCV DAA therapy and 53 (52%) reimbursed at least one DAA therapy. Among all countries with DAA therapy reimbursement (n=109), 66 (61%) required specialist prescribing, eight (7%) had retreatment restrictions, seven (6%) had an illicit drug use restriction, five (5%) had an alcohol use restriction, and three (3%) had liver disease restrictions. Global access to DAA reimbursement remains uneven, with LMICs having comparatively low reimbursement compared with high-income countries. To meet WHO goals for HCV elimination, efforts should be made to assist countries, particularly LMICs, to increase access to DAA reimbursement and remove reimbursement restrictions-especially prescriber-type restrictions-to ensure universal access.
Topics: Humans; Sofosbuvir; Antiviral Agents; Hepatitis C, Chronic; Hepatitis C; Hepacivirus; Benzimidazoles; Benzopyrans; Carbamates; Heterocyclic Compounds, 4 or More Rings
PubMed: 38367631
DOI: 10.1016/S2468-1253(23)00335-7 -
Hepatology (Baltimore, Md.) Dec 2023Chronic HEV infections remain a serious problem in immunocompromised patients, as specifically approved antiviral drugs are unavailable. In 2020, a 24-week multicenter...
BACKGROUND AND AIMS
Chronic HEV infections remain a serious problem in immunocompromised patients, as specifically approved antiviral drugs are unavailable. In 2020, a 24-week multicenter phase II pilot trial was carried out, evaluating the nucleotide analog sofosbuvir by treating nine chronically HEV-infected patients with sofosbuvir (Trial Number NCT03282474). During the study, antiviral therapy reduced virus RNA levels initially but did not lead to a sustained virologic response. Here, we characterize the changes in HEV intrahost populations during sofosbuvir treatment to identify the emergence of treatment-associated variants.
APPROACH AND RESULTS
We performed high-throughput sequencing on RNA-dependent RNA polymerase sequences to characterize viral population dynamics in study participants. Subsequently, we used an HEV-based reporter replicon system to investigate sofosbuvir sensitivity in high-frequency variants. Most patients had heterogenous HEV populations, suggesting high adaptability to treatment-related selection pressures. We identified numerous amino acid alterations emerging during treatment and found that the EC 50 of patient-derived replicon constructs was up to ~12-fold higher than the wild-type control, suggesting that variants associated with lower drug sensitivity were selected during sofosbuvir treatment. In particular, a single amino acid substitution (A1343V) in the finger domain of ORF1 could reduce susceptibility to sofosbuvir significantly in 8 of 9 patients.
CONCLUSIONS
In conclusion, viral population dynamics played a critical role during antiviral treatment. High population diversity during sofosbuvir treatment led to the selection of variants (especially A1343V) with lower sensitivity to the drug, uncovering a novel mechanism of resistance-associated variants during sofosbuvir treatment.
Topics: Humans; Sofosbuvir; Antiviral Agents; Hepatitis E; Sustained Virologic Response; Drug Therapy, Combination; Hepacivirus; Genotype; Treatment Outcome
PubMed: 37334496
DOI: 10.1097/HEP.0000000000000514 -
Cellular Oncology (Dordrecht) Nov 2023Cancer cells are characterized as the uncontrolled proliferation, which demands high levels of nucleotides that are building blocks for DNA synthesis and replication....
PURPOSE
Cancer cells are characterized as the uncontrolled proliferation, which demands high levels of nucleotides that are building blocks for DNA synthesis and replication. CAD (carbamoyl-phosphate synthetase 2, aspartate transcarbamylase and dihydroorotase) is a trifunctional enzyme that initiates the de novo pyrimidine synthesis, which is normally enhanced in cancer cells to preserve the pyrimidine pool for cell division. Glioma, representing most brain cancer, is highly addicted to nucleotides like pyrimidine to sustain the abnormal growth and proliferation of cells. CAD is previously reported to be dysregulated in glioma, but the underlying mechanism remains unclear.
METHODS
The expression of CAD and CHIP (carboxyl terminus of Hsc70-interacting protein) protein in normal brain cells and three glioblastoma (GBM) cell lines were measured by immunoblots. Lentiviruses-mediated expression of target proteins or shRNAs were used to specifically overexpress or knock down CAD and CHIP. Cell counting, colony formation, apoptosis and cell cycle assays were used to assess the roles of CAD and CHIP in GBM cell proliferation and survival. Co-immunoprecipitation and ubiquitination assays were used to examine the interaction of CHIP with CAD and the ubiquitination of CAD. The correlation of CAD and CHIP expression with GBM patients' survival was obtained by analyzing the GlioVis database.
RESULTS
In this study, we showed that the expression of CAD was upregulated in glioma, which was positively correlated with the tumor grade and survival of glioma patients. Knockdown of CAD robustly inhibited the cell proliferation and colony formation of GBM cells, indicating the essential role of CAD in the pathogenesis of GBM. Mechanistically, we firstly identified that CAD was modified by the K29-linked polyubiquitination, which was mediated by the E3 ubiquitin ligase CHIP. By interacting with and ubiquitinating CAD, CHIP enhanced its proteasomal and lysosomal degradation, which accounted for the anti-proliferative role of CHIP in GBM cells. To sustain the expression of CAD, CHIP is significantly downregulated, which is correlated with the poor prognosis and survival of GBM patients. Notably, the low level of CHIP and high level of CAD overall predict the short survival of GBM patients.
CONCLUSION
Altogether, these results illustrated the essential role of CAD in GBM and revealed a novel therapeutic strategy for CAD-positive and CHIP-negative cancer.
PubMed: 37982961
DOI: 10.1007/s13402-023-00899-2 -
Leukemia Jan 2024Targeting nucleotide biosynthesis is a proven strategy for the treatment of cancer but is limited by toxicity, reflecting the fundamental nucleotide requirement of...
Targeting nucleotide biosynthesis is a proven strategy for the treatment of cancer but is limited by toxicity, reflecting the fundamental nucleotide requirement of dividing cells. The rate limiting step in de novo pyrimidine synthesis is of interest, being catalyzed by two homologous enzymes, CTP synthase 1 (CTPS1) and CTPS2, that could be differentially targeted. Herein, analyses of publicly available datasets identified an essential role for CTPS1 in multiple myeloma (MM), linking high expression of CTPS1 (but not CTPS2) with advanced disease and poor outcomes. In cellular experiments, CTPS1 knockout induced apoptosis of MM cell lines. Exposure of MM cells to STP-B, a novel and highly selective pharmacological inhibitor of CTPS1, inhibited proliferation, induced S phase arrest and led to cell death by apoptosis. Mechanistically, CTPS1 inhibition by STP-B activated DNA damage response (DDR) pathways and induced double-strand DNA breaks which accumulated in early S phase. Combination of STP-B with pharmacological inhibitors of key components of the DDR pathway (ATR, CHEK1 or WEE1) resulted in synergistic growth inhibition and early apoptosis. Taken together, these findings identify CTPS1 as a promising new target in MM, either alone or in combination with DDR pathway inhibition.
Topics: Humans; Multiple Myeloma; Apoptosis; Cell Death; Ataxia Telangiectasia Mutated Proteins; Nucleotides; DNA Damage; Cell Line, Tumor; Checkpoint Kinase 1; Protein-Tyrosine Kinases; Cell Cycle Proteins
PubMed: 37898670
DOI: 10.1038/s41375-023-02071-z -
Nature Communications Nov 2023Methyl jasmonate (MeJA) is a known elicitor of plant specialized metabolism, including triterpenoid saponins. Saponaria vaccaria is an annual herb used in traditional...
Methyl jasmonate (MeJA) is a known elicitor of plant specialized metabolism, including triterpenoid saponins. Saponaria vaccaria is an annual herb used in traditional Chinese medicine, containing large quantities of oleanane-type triterpenoid saponins with anticancer properties and structural similarities to the vaccine adjuvant QS-21. Leveraging the MeJA-elicited saponin biosynthesis, we identify multiple enzymes catalyzing the oxidation and glycosylation of triterpenoids in S. vaccaria. This exploration is aided by Pacbio full-length transcriptome sequencing and gene expression analysis. A cellulose synthase-like enzyme can not only glucuronidate triterpenoid aglycones but also alter the product profile of a cytochrome P450 monooxygenase via preference for the aldehyde intermediate. Furthermore, the discovery of a UDP-glucose 4,6-dehydratase and a UDP-4-keto-6-deoxy-glucose reductase reveals the biosynthetic pathway for the rare nucleotide sugar UDP-D-fucose, a likely sugar donor for fucosylation of plant natural products. Our work enables the production and optimization of high-value saponins in microorganisms and plants through synthetic biology approaches.
Topics: Triterpenes; Transcriptome; Saponaria; Vaccaria; Plants; Saponins; Uridine Diphosphate; Glucose; Sugars
PubMed: 37925486
DOI: 10.1038/s41467-023-42877-0 -
Journal of Hepatology Aug 2023The combination of sofosbuvir, velpatasvir and voxilaprevir (SOF/VEL/VOX) is recommended for the retreatment of patients with HCV infection in whom previous... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND & AIMS
The combination of sofosbuvir, velpatasvir and voxilaprevir (SOF/VEL/VOX) is recommended for the retreatment of patients with HCV infection in whom previous direct-acting antiviral (DAA) treatment failed. However, whether ribavirin further increases the therapeutic efficacy of SOF/VEL/VOX retreatment remains unclear. We aimed to test this hypothesis in a randomized-controlled trial.
METHODS
We randomly assigned 315 patients with DAA treatment failure from five Egyptian sites into two groups. Group A (n = 158) received SOF/VEL/VOX for 12 weeks, and group B (n = 157) received SOF/VEL/VOX + weight-based ribavirin for 12 weeks. Therapeutic efficacy was defined as SVR12 (sustained virologic response 12 weeks after treatment end). Safety and tolerability were evaluated by monitoring treatment-related adverse events (AEs) and laboratory abnormalities.
RESULTS
Males comprised 53.9% of group A and 57.1% of group B (p = 0.58); mean ages were 51.8 and 47.3 years in group A and B, respectively. Seventeen patients in each group were lost to follow-up. SVR12 rates were 87.3% (138/158) by intention-to-treat analysis and 97.8% (138/141) by per-protocol analysis in group A; and 87.9% (138/157) and 98.5% (138/140), respectively, in group B (p = n.s. for intention-to-treat and per-protocol analyses). Both regimens were well-tolerated, with no deaths and only one serious AE (anemia) in group B, which required ribavirin discontinuation. Fifty-five patients in group A vs. 77 in group B experienced any AE (p = 0.002).
CONCLUSION
This randomized-controlled trial showed equal, high efficacy of both regimens for the retreatment of previous DAA failures, although ribavirin was associated with more AEs. Therefore SOF/VEL/VOX monotherapy should be the preferred retreatment strategy. CLINCIALTRIALS.
GOV NUMBER
NCT04695769.
IMPACT AND IMPLICATIONS
HCV treatment guidelines recommend retreatment of direct-acting antiviral (DAA) treatment failures with the combination of sofosbuvir, velpatasvir and voxilaprevir (SOF/VEL/VOX) for 12 weeks. However, whether ribavirin exerts an additional/synergistic effect remains unclear. The present study confirmed that SOF/VEL/VOX without ribavirin is the best regimen for retreatment of DAA treatment failures, and thus will help guide clinicians caring for patients who are not cured with a first course of DAA therapy.
Topics: Male; Humans; Female; Sofosbuvir; Antiviral Agents; Hepatitis C, Chronic; Ribavirin; Treatment Outcome; Drug Therapy, Combination; Hepacivirus; Hepatitis C; Retreatment; Genotype
PubMed: 37088312
DOI: 10.1016/j.jhep.2023.04.011