Project description:Fate determination of primordial germ cells (PGCs) is regulated in a multi-layered manner, involving signaling pathways, epigenetic mechanisms and transcriptional control. Epigenetic mechanisms are expected to be closely related with metabolic mechanisms but the detailed molecular machinery linking these two layers remain poorly understood. Here, we show that the hexosamine biosynthetic pathway controls PGC fate determination via O-linked -N-acetylglucosamine (O-GlcNAc) modification. Consistent with this model, reduction of carbohydrate metabolism via a maternal ketogenic diet that decreases O-GlcNAcylation levels causes repression of PGC formation in vivo. Further, the effect of maternal ketogenic diet intake until mid-gestation affected the number of ovarian germ cells in newborn pups. Taken together, we show that nutritional and metabolic mechanisms play a previously unappreciated role in PGC fate determination.
Project description:Fate determination of primordial germ cells (PGCs) is regulated in a multi-layered manner, involving signaling pathways, epigenetic mechanisms, and transcriptional control. Chemical modification of macromolecules, including epigenetics, is expected to be closely related with metabolic mechanisms but the detailed molecular machinery linking these two layers remains poorly understood. Here, we show that the hexosamine biosynthetic pathway controls PGC fate determination via O-linked β-N-acetylglucosamine (O-GlcNAc) modification. Consistent with this model, reduction of carbohydrate metabolism via a maternal ketogenic diet that decreases O-GlcNAcylation levels causes repression of PGC formation in vivo. Moreover, maternal ketogenic diet intake until mid-gestation affects the number of ovarian germ cells in newborn pups. Taken together, we show that nutritional and metabolic mechanisms play a previously unappreciated role in PGC fate determination.
Project description:The addition of O-GlcNAc (a single β-D-N-acetylglucosamine sugar at serine and threonine residues) by O-GlcNAc transferase (OGT) and removal by O-GlcNAcase (OGA) maintains homeostatic levels of O-GlcNAc. We investigated the role of OGlcNAc homeostasis in hematopoiesis utilizing G1E-ER4 cells carrying a GATA-1 transcription factor fused to the estrogen receptor (GATA-1ER) that undergo erythropoiesis following the addition of β-estradiol (E2) and myeloid leukemia cells that differentiate into neutrophils in the presence of all-trans retinoic acid. During G1E-ER4 differentiation, a decrease in overall O-GlcNAc levels and an increase in GATA-1 interactions with OGT and OGA were observed. Transcriptome analysis on G1E-ER4 cells differentiated in the presence of Thiamet-G (TMG), an OGA inhibitor, identified expression changes in 433 GATA-1 target genes. Chromatin immunoprecipitation demonstrated that the occupancy of GATA-1, OGT, and OGA at Laptm5 gene GATA site was decreased with TMG. Myeloid leukemia cells showed a decline in O-GlcNAc levels during differentiation and TMG reduced the expression of genes involved in differentiation. Sustained treatment with TMG in G1E-ER4 cells prior to differentiation caused a reduction of hemoglobin positive cells during differentiation. Our results show that alterations in O-GlcNAc homeostasis disrupt transcriptional programs causing differentiation errors suggesting a vital role of O-GlcNAcylation in control of cell fate.
Project description:Heparan sulfate (HS), a long linear polysaccharide, is implicated in various steps of tumorigenesis, including angiogenesis. We successfully interfered with HS biosynthesis using a peracetylated 4-deoxy analog of the HS constituent GlcNAc and studied the compoundM-bM-^@M-^Ys metabolic fate and its effect on angiogenesis. The 4-deoxy analog was activated intracellularly into UDP-4-deoxy-GlcNAc and HS expression was inhibited up to ~96% (IC50 = 16 M-BM-5M). HS chain size was reduced, without detectable incorporation of the 4-deoxy analog, likely due to reduced levels of UDP-GlcNAc and/or inhibition of glycosyltransferase activity. Comprehensive gene expression analysis revealed reduced expression of genes regulated by HS binding growth factors as FGF-2 and VEGF. Cellular binding and signaling of these angiogenic factors was inhibited. Micro-injection in zebrafish embryos strongly reduced HS biosynthesis, and angiogenesis was inhibited in both zebrafish and chicken model systems. All these data identify 4-deoxy-GlcNAc as a potent inhibitor of HS synthesis which hampers pro-angiogenic signaling and neo-vessel formation. 9 samples were analyzed: 3 biological replicates from untreated SKOV3 cells, 3 biological replicates from SKOV3 cells treated with peracetylated GlcNAc, 3 biological replicates from SKOV3 cells treated with peracetylated 4-deoxy-GlcNAc
Project description:O-GlcNAcylation is a reversible post-translational modification controlled by the activity of two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). In the liver, O-GlcNAcylation has emerged as an important regulatory mechanism underlying normal liver physiology and metabolic disease.To address whether OGT acts as a critical hepatic nutritional node, mice with a constitutive hepatocyte-specific deletion of OGT (OGTLKO) were generated.Analyses of 4-week-old OGTLKO mice revealed significant oxidative and endoplasmic reticulum stress, and DNA damage, together with inflammation and fibrosis, in the liver. Susceptibility to oxidative and endoplasmic reticulum stress- induced apoptosis was also elevated in OGTLKO hepatocytes. Although OGT expression was partially recovered in the liver of 8- week-old OGTLKO mice, hepatic injury and fibrosis were not rescued but rather worsened with time. Interestingly, weaning of OGTLKO mice on a ketogenic diet (low carbohydrate, high fat) fully prevented the hepatic alterations induced by OGT deletion, indicating that reduced carbohydrate intake protects an OGT-deficient liver. These findings pinpoint OGT as a key mediator of hepatocyte homeostasis and survival upon carbohydrate intake and validate OGTLKO mice as a valuable model for assessing therapeutical approaches of advanced liver fibrosis.
Project description:We applied the chemical reporter-based metabolic labeling method to acquire O-GlcNAc modified proteins chromatin loci. Human breast cancer cell line MCF-7, as well as the genotoxic stress (Adriamycin) adapted cells MCF-7/ADR, were fed with 1 mM GalNAz. Metabolic labeled O-GlcNAz chromatin were crosslinked, sonicated and enriched by bioorthogonal chemistry. Then, the genomic DNA fragments bounded by O-GlcNAc mark were de-crosslinked, and constructed into libraries following by next-generation sequencing (Chemoselective O-GlcNAc chromatin sequencing, COGC-seq). To verify the robustness of this chemical reporter-based metabolic labeling method, we compared the results in MCF-7 and MCF-7/ADR cells with classical lectin succinylated wheat germ agglutinin (sWGA) ChIP-seq strategy. We also analyzed gene expression MCF-7 and MCF-7/ADR cells by RNA-seq.
Project description:This phase I clinical trial tests the immune effects of fermented wheat germ in patients with advanced solid tumor cancers who are being treated with standard of care checkpoint inhibitors. Fermented wheat germ is a nutritional supplement that some claim is a "dietary food for special medical purposes for cancer patients" to support them in treatment. There have also been claims that fermented wheat germ is "clinically proven" and "recognized by medical experts" to "enhance oncological treatment" and boost immune response to cancer; however, there are currently no documented therapeutic effects of fermented wheat germ as a nutritional supplement. Checkpoint inhibitors, given as part of standard of care for advanced solid tumors, are a type of immunotherapy that may help the body’s immune system attack the cancer and may interfere with the ability of tumor cells to grow and spread. The information gained from this trial may allow researchers to determine if there is any value of giving fermented wheat germ with standard of care checkpoint inhibitors for patients with advanced solid tumor malignancies.
Project description:Heparan sulfate (HS), a long linear polysaccharide, is implicated in various steps of tumorigenesis, including angiogenesis. We successfully interfered with HS biosynthesis using a peracetylated 4-deoxy analog of the HS constituent GlcNAc and studied the compound’s metabolic fate and its effect on angiogenesis. The 4-deoxy analog was activated intracellularly into UDP-4-deoxy-GlcNAc and HS expression was inhibited up to ~96% (IC50 = 16 µM). HS chain size was reduced, without detectable incorporation of the 4-deoxy analog, likely due to reduced levels of UDP-GlcNAc and/or inhibition of glycosyltransferase activity. Comprehensive gene expression analysis revealed reduced expression of genes regulated by HS binding growth factors as FGF-2 and VEGF. Cellular binding and signaling of these angiogenic factors was inhibited. Micro-injection in zebrafish embryos strongly reduced HS biosynthesis, and angiogenesis was inhibited in both zebrafish and chicken model systems. All these data identify 4-deoxy-GlcNAc as a potent inhibitor of HS synthesis which hampers pro-angiogenic signaling and neo-vessel formation.