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Nature Communications Nov 2023Tankyrase 1 and 2 are ADP-ribosyltransferases that catalyze formation of polyADP-Ribose (PAR) onto themselves and their binding partners. Tankyrase protein levels are...
Tankyrase 1 and 2 are ADP-ribosyltransferases that catalyze formation of polyADP-Ribose (PAR) onto themselves and their binding partners. Tankyrase protein levels are regulated by the PAR-binding E3 ligase RNF146, which promotes K48-linked polyubiquitylation and proteasomal degradation of tankyrase and its partners. We identified a novel interaction between tankyrase and a distinct class of E3 ligases: the RING-UIM (Ubiquitin-Interacting Motif) family. We show that RNF114 and RNF166 bind and stabilize monoubiquitylated tankyrase and promote K11-linked diubiquitylation. This action competes with RNF146-mediated degradation, leading to stabilization of tankyrase and its binding partner, Angiomotin, a cancer cell signaling protein. Moreover, we identify multiple PAR-binding E3 ligases that promote ubiquitylation of tankyrase and induce stabilization or degradation. Discovery of K11 ubiquitylation that opposes degradation, along with identification of multiple PAR-binding E3 ligases that ubiquitylate tankyrase, provide insights into mechanisms of tankyrase regulation and may offer additional uses for tankyrase inhibitors in cancer therapy.
Topics: Ubiquitin-Protein Ligases; Tankyrases; Ubiquitination; ADP Ribose Transferases; Catalysis; Ribose
PubMed: 37938264
DOI: 10.1038/s41467-023-42939-3 -
Metabolites Dec 2023NAD synthetase 1 (encoded by the gene NADSYN1) is a cytosolic enzyme that catalyzes the final step in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) from...
NAD synthetase 1 (encoded by the gene NADSYN1) is a cytosolic enzyme that catalyzes the final step in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) from tryptophan and nicotinic acid. NADSYN1 deficiency has recently been added to the spectrum of congenital NAD+ deficiency disorders. To gain insight into the metabolic consequences of NADSYN1 deficiency, the encoding gene was disrupted in A549 and HEK293T cells, and the metabolome was profiled in the presence of different NAD+ precursors, including tryptophan, nicotinamide and nicotinic acid. We demonstrate that when precursors of the NAD+ salvage pathway in the form of nicotinamide become limiting, NADSYN1 deficiency results in a decline in intracellular NAD+ levels even in the presence of other potential NAD+ sources such as tryptophan and nicotinic acid. As a consequence, alterations in 122 and 69 metabolites are observed in NADSYN1-deficient A549 and HEK293T cells compared to the wild-type cell line (FC > 2 and < 0.05). We thus show that NADSYN1 deficiency results in a metabolic phenotype characterized by alterations in glycolysis, the TCA cycle, the pentose phosphate pathway, and the polyol pathway.
PubMed: 38132878
DOI: 10.3390/metabo13121196 -
PLoS Pathogens Jul 2023Staphylococcus aureus is an important pathogen that leads to significant disease through multiple routes of infection. We recently published a transposon sequencing...
Staphylococcus aureus is an important pathogen that leads to significant disease through multiple routes of infection. We recently published a transposon sequencing (Tn-seq) screen in a mouse acute pneumonia model and identified a hypothetical gene (SAUSA300_1902, pgl) with similarity to a lactonase of Escherichia coli involved in the pentose phosphate pathway (PPP) that was conditionally essential. Limited studies have investigated the role of the PPP in physiology and pathogenesis of S. aureus. We show here that mutation of pgl significantly impacts ATP levels and respiration. RNA-seq analysis of the pgl mutant and parent strains identified compensatory changes in gene expression for glucose and gluconate as well as reductions in the pyrimidine biosynthesis locus. These differences were also evident through unbiased metabolomics studies and 13C labeling experiments that showed mutation of pgl led to reductions in pyrimidine metabolism including decreases in ribose-5P, UMP and GMP. These nucleotide reductions impacted the amount of extracellular DNA in biofilms and reduced biofilm formation. Mutation also limited the capacity of the strain to resist oxidant damage induced by hydrogen peroxide and paraquat and subsequent intracellular survival inside macrophages. Changes in wall teichoic acid impacted susceptibility to hydrogen peroxide. We demonstrated the importance of these changes on virulence in three different models of infection, covering respiratory, skin and septicemia, demonstrating the need for proper PPP function in all models. This work demonstrates the multifaceted role metabolism can play in multiple aspects of S. aureus pathogenesis.
Topics: Animals; Mice; Staphylococcus aureus; Pentose Phosphate Pathway; Hydrogen Peroxide; Staphylococcal Infections; Virulence; Escherichia coli; Biofilms
PubMed: 37440594
DOI: 10.1371/journal.ppat.1011531 -
Journal of Translational Medicine Oct 2023Hepatic ischemia-reperfusion (IR) injury is the primary reason for complications following hepatectomy and liver transplantation (LT). Insulin-induced gene 2 (Insig2) is...
BACKGROUND
Hepatic ischemia-reperfusion (IR) injury is the primary reason for complications following hepatectomy and liver transplantation (LT). Insulin-induced gene 2 (Insig2) is one of several proteins that anchor the reticulum in the cytoplasm and is essential for metabolism and inflammatory responses. However, its function in IR injury remains ambiguous.
METHODS
Insig2 global knock-out (KO) mice and mice with adeno-associated-virus8 (AAV8)-delivered Insig2 hepatocyte-specific overexpression were subjected to a 70% hepatic IR model. Liver injury was assessed by monitoring hepatic histology, inflammatory responses, and apoptosis. Hypoxia/reoxygenation stimulation (H/R) of primary hepatocytes and hypoxia model induced by cobalt chloride (CoCl) were used for in vitro experiments. Multi-omics analysis of transcriptomics, proteomics, and metabolomics was used to investigate the molecular mechanisms underlying Insig2.
RESULTS
Hepatic Insig2 expression was significantly reduced in clinical samples undergoing LT and the mouse IR model. Our findings showed that Insig2 depletion significantly aggravated IR-induced hepatic inflammation, cell death and injury, whereas Insig2 overexpression caused the opposite phenotypes. The results of in vitro H/R experiments were consistent with those in vivo. Mechanistically, multi-omics analysis revealed that Insig2 is associated with increased antioxidant pentose phosphate pathway (PPP) activity. The inhibition of glucose-6-phosphate-dehydrogenase (G6PD), a rate-limiting enzyme of PPP, rescued the protective effect of Insig2 overexpression, exacerbating liver injury. Finally, our findings indicated that mouse IR injury could be attenuated by developing a nanoparticle delivery system that enables liver-targeted delivery of substrate of PPP (glucose 6-phosphate).
CONCLUSIONS
Insig2 has a protective function in liver IR by upregulating the PPP activity and remodeling glucose metabolism. The supplementary glucose 6-phosphate (G6P) salt may serve as a viable therapeutic target for alleviating hepatic IR.
Topics: Animals; Mice; Antioxidants; Apoptosis; Glucose; Hepatectomy; Hepatocytes; Hypoxia; Insulins; Liver; Liver Diseases; Liver Transplantation; Phosphates; Reperfusion Injury
PubMed: 37858181
DOI: 10.1186/s12967-023-04564-y -
Molecular Biology Reports Jan 2024D-ribose, an ubiquitous pentose compound found in all living cells, serves as a vital constituent of numerous essential biomolecules, including RNA, nucleotides, and... (Review)
Review
D-ribose, an ubiquitous pentose compound found in all living cells, serves as a vital constituent of numerous essential biomolecules, including RNA, nucleotides, and riboflavin. It plays a crucial role in various fundamental life processes. Within the cellular milieu, exogenously supplied D-ribose can undergo phosphorylation to yield ribose-5-phosphate (R-5-P). This R-5-P compound serves a dual purpose: it not only contributes to adenosine triphosphate (ATP) production through the nonoxidative phase of the pentose phosphate pathway (PPP) but also participates in nucleotide synthesis. Consequently, D-ribose is employed both as a therapeutic agent for enhancing cardiac function in heart failure patients and as a remedy for post-exercise fatigue. Nevertheless, recent clinical studies have suggested a potential link between D-ribose metabolic disturbances and type 2 diabetes mellitus (T2DM) along with its associated complications. Additionally, certain in vitro experiments have indicated that exogenous D-ribose exposure could trigger apoptosis in specific cell lines. This article comprehensively reviews the current advancements in D-ribose's digestion, absorption, transmembrane transport, intracellular metabolic pathways, impact on cellular behaviour, and elevated levels in diabetes mellitus. It also identifies areas requiring further investigation.
Topics: Humans; Diabetes Mellitus, Type 2; Ribose; Heart Failure; Metabolic Diseases; Adenosine Triphosphate
PubMed: 38281218
DOI: 10.1007/s11033-023-09076-y -
Cell Reports Jul 2023Eukaryotic RNA pol II transcripts are capped at the 5' end by the methylated guanosine (mG) moiety. In higher eukaryotes, CMTR1 and CMTR2 catalyze cap-proximal ribose...
Eukaryotic RNA pol II transcripts are capped at the 5' end by the methylated guanosine (mG) moiety. In higher eukaryotes, CMTR1 and CMTR2 catalyze cap-proximal ribose methylations on the first (cap1) and second (cap2) nucleotides, respectively. These modifications mark RNAs as "self," blocking the activation of the innate immune response pathway. Here, we show that loss of mouse Cmtr1 or Cmtr2 leads to embryonic lethality, with non-overlapping sets of transcripts being misregulated, but without activation of the interferon pathway. In contrast, Cmtr1 mutant adult mouse livers exhibit chronic activation of the interferon pathway, with multiple interferon-stimulated genes being expressed. Conditional deletion of Cmtr1 in the germline leads to infertility, while global translation is unaffected in the Cmtr1 mutant mouse liver and human cells. Thus, mammalian cap1 and cap2 modifications have essential roles in gene regulation beyond their role in helping cellular transcripts to evade the innate immune system.
Topics: Humans; Animals; Mice; Methylation; RNA Caps; Ribose; Methyltransferases; Interferons; Fertility; Mammals
PubMed: 37436893
DOI: 10.1016/j.celrep.2023.112786 -
International Journal of Biological... 2023Metabolic reprogramming is a hallmark of cancers crucial for fulfilling the needs of energy, building blocks, and antioxidants to support tumor cells' rapid...
Metabolic reprogramming is a hallmark of cancers crucial for fulfilling the needs of energy, building blocks, and antioxidants to support tumor cells' rapid proliferation and to cope with the harsh microenvironment. Pre-B-cell leukemia transcription factor 3 (PBX3) is a member of the PBX family whose expression is up-regulated in various tumors, however, whether it is involved in tumor cell metabolic reprogramming remains unclear. Herein, we report that PBX3 is a positive regulator of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the pentose phosphate pathway (PPP). PBX3 promoted transcriptional activity in tumor cells by binding directly to its promoter, leading to PPP stimulation and enhancing the production of nucleotides and NADPH, a crucial reductant, thereby promoting nucleic acid and lipid biosynthesis while decreasing intracellular reactive oxygen species levels. The PBX3/G6PD axis also promoted tumorigenic potential and . Collectively, these findings reveal a novel function of PBX3 as a regulator of G6PD, linking its oncogenic activity with tumor cell metabolic reprogramming, especially PPP. Furthermore, our results suggested that PBX3 is a potential target for metabolic-based anti-tumor therapeutic strategies.
Topics: Humans; Glucosephosphate Dehydrogenase; Pentose Phosphate Pathway; Reactive Oxygen Species; Carcinogenesis; Colorectal Neoplasms; Tumor Microenvironment
PubMed: 37781025
DOI: 10.7150/ijbs.86279 -
Frontiers in Physiology 2023The enzyme glucose-6-phosphate dehydrogenase (G6PDH) plays crucial roles in glucose homeostasis and the pentose phosphate pathway (PPP), being also involved in redox... (Review)
Review
The enzyme glucose-6-phosphate dehydrogenase (G6PDH) plays crucial roles in glucose homeostasis and the pentose phosphate pathway (PPP), being also involved in redox metabolism. The PPP is an important metabolic pathway that produces ribose and nicotinamide adenine dinucleotide phosphate (NADPH), which are essential for several physiologic and biochemical processes, such as the synthesis of fatty acids and nucleic acids. As a rate-limiting step in PPP, G6PDH is a highly conserved enzyme and its deficiency can lead to severe consequences for the organism, in particular for cell growth. Insufficient G6PDH activity can lead to cell growth arrest, impaired embryonic development, as well as a reduction in insulin sensitivity, inflammation, diabetes, and hypertension. While research on G6PDH and PPP has historically focused on mammalian models, particularly human disorders, recent studies have shed light on the regulation of this enzyme in arthropods, where new functions were discovered. This review will discuss the role of arthropod G6PDH in regulating redox homeostasis and immunometabolism and explore potential avenues for further research on this enzyme in various metabolic adaptations.
PubMed: 38046951
DOI: 10.3389/fphys.2023.1287090 -
Journal of Obstetrics and Gynaecology :... Dec 2023BAG3 is a co-chaperone BAG family protein that plays important roles in protein homeostasis, cell survival, cell motility, and tumour metastasis. This study aimed to...
BAG3 is a co-chaperone BAG family protein that plays important roles in protein homeostasis, cell survival, cell motility, and tumour metastasis. This study aimed to clarify the clinicopathological and prognostic implications of mRNA expression in tumours. We performed bioinformatics analysis on mRNA expression using TCGA, XIANTAO, UALCAN, and Kaplan-Meier plotter databases. mRNA expression was downregulated in breast and endometrial cancers and positively correlated with favourable PAM50 subtyping in breast cancer,clinical stage and short overall survival in ovarian cancer and negatively correlated with T stage, clinical stage, and histological grade in cervical and endometrial cancers. The top -related pathways included ligand-receptor interactions and activity, DNA packaging and nucleosomes, hormonal responses, membrane regions, microdomains and rafts, and endosomes in breast cancer; ligand-receptor interactions, transmembrane transporters and channels, cell adhesion, and keratinisation in cervical cancer; ligand-receptor interactions, anion transmembrane transporters, lipoproteins, keratinisation, cell adhesion, and protein processing in endometrial cancer; metabolism of porphyrin, chlorophyll, pentose, uronic acid, ascorbate, and alternate and cell adhesion in ovarian cancer. expression could represent a potential marker for carcinogenesis, histogenesis, aggressive behaviours, and prognosis in gynecological cancers.IMPACT STATEMENT BAG3 regulates cell activity, autophagy, and resistance to apoptosis through multiple domains and plays an important role in tumour development. BAG3 positively regulates tumour cell invasion and migration in cervical and ovarian cancers. BAG3 expression is closely associated with histogenesis, clinicopathology, and prognosis in gynecological cancers and is involved in signalling pathways associated with the control of cell proliferation, migration, invasion, and drug resistance in tumours. Abnormal BAG3 expression can be employed as a possible marker of tumour development, invasion, and prognosis, providing new ideas for treating cancer.
Topics: Female; Humans; Prognosis; Cell Line, Tumor; Adaptor Proteins, Signal Transducing; RNA, Messenger; Ligands; Apoptosis Regulatory Proteins; Ovarian Neoplasms; Computational Biology; Endometrial Neoplasms; Breast Neoplasms
PubMed: 37377218
DOI: 10.1080/01443615.2023.2228899 -
Free Radical Biology & Medicine Nov 2023Ferroptosis is a novel form of cell death triggered by iron-dependent lipid peroxidation. Recent findings suggest that inhibiting system χc-induces ferroptosis by...
Ferroptosis is a novel form of cell death triggered by iron-dependent lipid peroxidation. Recent findings suggest that inhibiting system χc-induces ferroptosis by reducing intracellular cystine levels, and that ferroptosis in renal tubular epithelial cells (RTECs) contributes to acute kidney injury (AKI) and diabetic nephropathy. Moreover, 2-deoxy-d-ribose (dRib) has been shown to inhibit cystine uptake through xCT, the functional unit of system χc-, in β-cells. This study aimed to investigate if dRib induces ferroptosis in RTECs and identify the underlying mechanisms. dRib treatment reduced cystine uptake and glutathione (GSH) content, and increased intracellular levels of malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), lipid reactive oxygen species (ROS), and cell death in both NRK-52E cells and primary cultured RTECs. However, treatment with inhibitors of ferroptosis, such as deferoxamine (DFO), ferrostatin-1 (Fer-1), and liproxstatin-1 (Lip-1), counteracted the effects of dRib on GSH, MDA, 4-HNE, and lipid ROS levels, as well as cell death. Additionally, 2-mercaptoethanol (2-ME) treatment or xCT gene overexpression protected against dRib-induced changes. Moreover, transmission electron microscopy revealed dRib-induced mitochondrial shrinkage, decrease in cristae number, and outer membrane rupture. Furthermore, dRib treatment upregulated the expression of genes associated with ferroptosis, and downregulated xCT protein expression. The decrease in xCT protein caused by dRib was consistently observed even when treated with the protein synthesis inhibitor cycloheximide. However, treatment with the proteasome inhibitor MG132 reversed the dRib-induced decrease in xCT protein expression. Additionally, dRib increased xCT protein ubiquitination. Overall, dRib induces ferroptosis in RTECs by degrading xCT protein through ubiquitin-proteasome system (UPS), resulting in reduced intracellular cystine uptake. Therefore, targeting the regulation of system χc-through UPS could be a potential therapeutic approach for AKI and diabetic nephropathy.
Topics: Humans; Ferroptosis; Reactive Oxygen Species; Oxidative Stress; Ribose; Proteasome Endopeptidase Complex; Apoptosis; Cystine; Diabetic Nephropathies; Proteolysis; Glutathione; Epithelial Cells; Acute Kidney Injury; Ubiquitins; Lipids
PubMed: 37659699
DOI: 10.1016/j.freeradbiomed.2023.08.027