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You searched for subject:(hexosamine biosynthesis pathway). Showing records 1 – 3 of 3 total matches.

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University of Adelaide

1. Frank, Laura Alice. The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence.

Degree: 2012, University of Adelaide

Maternal diabetes and conditions such as obesity in which blood glucose levels are elevated are associated with reduced fertility and poor pregnancy outcomes. Many studies have examined the effects of hyperglycaemia on the early embryo and fetus; however, it is becoming increasingly evident that the peri-conceptual environment surrounding the oocyte has a significant impact on developmental competence and the long-term health of offspring. In this thesis, I aimed to investigate the role of the hexosamine biosynthesis pathway (HBP) in oocyte developmental competence. The HBP is a glucose-metabolising pathway which can also be upregulated by glucosamine, a potent hyperglycaemic mimetic which enters the HBP downstream of the rate-limiting enzyme. The HBP produces uridine diphosphate-N acetylglucosamine, which can be used for the β-O-linked glycosylation (O-GlcNAcylation) of proteins, regulating their function in a similar manner to phosphorylation. Firstly I established the effect of hyper- and hypo-glycaemic conditions during in vitro maturation (IVM) of mouse cumulus-oocyte complexes (COCs) on a range of measures associated with oocyte developmental competence, including cumulus expansion, meiotic maturation, cleavage and blastocyst development rates. A low (1 mM) glucose concentration achieved optimal oocyte competence, and glucose supplementation during only the first hour of IVM was necessary and sufficient to support oocyte maturation and embryo development to the blastocyst stage. Glucosamine was able to substitute for glucose during this first hour. In the absence of glucose throughout IVM, glucosamine was not able to increase developmental competence, and at higher concentrations (2.5 and 5 mM) had a detrimental effect on these outcomes. These experiments underscored the importance of the other glucose metabolic pathways, during COC maturation, and supported the concept that excess flux through the HBP has detrimental consequences. Using Western blots and immunohistochemistry, it was shown that both glucosamine and high glucose levels induced an increase in total O-GlcNAcylation in COCs, which was reduced in the presence of an inhibitor of the β-O-linked glycosyltransferase enzyme. Several specific proteins were identified using mass spectrometry as potential targets of O-GlcNAcylation in COCs, including heat-shock protein 90 (HSP90, both α and β isoforms). While glucosamine treatment of COCs significantly decreased blastocyst development rate, inhibiting HSP90 with 17-allylamino-17-demethoxygeldanamycin during IVM in the presence of glucosamine recovered blastocyst rates to control levels. This effect was not due to an increase in overall HSP90 levels, since inhibiting HSP90 in control COCs did not affect blastocyst rate. These results suggest O-GlcNacylated HSP90 has an aberrant function in the COC. This study is the first to examine in detail O-GlcNAcylation levels in the COC, and their correlation to oocyte developmental competence. HSP90 was identified as a potential target of O-GlcNAcylation in the COC,… Advisors/Committee Members: Thompson, Jeremy Gilbert E. (advisor), Sutton-McDowall, Melanie (advisor), Gilchrist, Robert Bruce (advisor), Russell, Darryl (advisor), Lane, Michelle Therese (advisor), School of Paediatrics and Reproductive Health (school).

Subjects/Keywords: glucose; glucosamine; cumulus-oocyte complex; hexosamine biosynthesis pathway; β-O-linked glycosylation

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APA (6th Edition):

Frank, L. A. (2012). The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/96463

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Frank, Laura Alice. “The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence.” 2012. Thesis, University of Adelaide. Accessed January 17, 2020. http://hdl.handle.net/2440/96463.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Frank, Laura Alice. “The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence.” 2012. Web. 17 Jan 2020.

Vancouver:

Frank LA. The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence. [Internet] [Thesis]. University of Adelaide; 2012. [cited 2020 Jan 17]. Available from: http://hdl.handle.net/2440/96463.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Frank LA. The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence. [Thesis]. University of Adelaide; 2012. Available from: http://hdl.handle.net/2440/96463

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


McMaster University

2. Walter, Lisa A. A High-Throughput Screening Campaign To Discover Novel Inhibitors Of Human L-glutamine: D-fructose-6-phosphate Amidotransferase 1.

Degree: PhD, 2013, McMaster University

Human L-glutamine:D-fructose-6-phosphate amidotransferase 1 (hGFAT1) is the first and rate-limiting enzyme of the hexosamine biosynthesis pathway (HBP) and is a potential target to help prevent secondary complications of type II diabetes. GFAT catalyzes the irreversible reaction between L-glutamine and D-fructose-6-phosphate to produce L-glutamate and D-glucosamine-6-phosphate. hGFAT1 is not commercially available and is difficult to obtain from natural sources. Thus, a recombinant method to generate and purify the enzyme was developed and is discussed herein. There are only a handful of known inhibitors available to study the enzyme and the majority of these are toxic, non-specific, or substrate analogs. A high-throughput screening campaign was undertaken in pursuit of novel hGFAT1 inhibitors. The bioactive subset of the Canadian Compound Collection was assayed in duplicate for GFAT inhibitory activity using a modified version of the Morgan-Elson assay. Out of the 3950 bioactives, 9 were identified as lead compounds. All of the compounds identified from the bioactive collection are novel GFAT inhibitors. A structure-activity relationship (SAR) analysis was performed on the lead compounds. Derivatives of the leads were also purchased or synthesized for inhibitory testing. Four distinct classes of compounds were identified as GFAT inhibitors: isoquinolines, aminothiazoles, pyridinones and quinones. The most potent lead compound elucidated from the SAR was dehydroiso-β-lapachone (IC50 1.5±0.5 µM). The mode of inhibition of dehydroiso-β-lapachone was determined to be non-competitive for both binding domains of recombinant hGFAT1. To validate the lead compounds as inhibitors of native hGFAT1 and to determine their cell permeability, a cell based assay was developed. HepG2 cell cultures were treated with an inhibitor and HBP metabolism was determined by measuring the levels of the end-product uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). UDP-GlcNAc was separated and detected by UPLC-ESI-TOF-MS and metabolite levels were normalized to cell concentration. The leads, alloxan, lapachol and amrinone all displayed hGFAT1 inhibition in cell culture.

Doctor of Philosophy (PhD)

Advisors/Committee Members: Capretta, Alfredo, Werstuck, G. H., Brennan, John D., Chemical Biology.

Subjects/Keywords: GFAT; HTS; diabetes; hexosamine biosynthesis pathway; Morgan-Elson assay; Analytical Chemistry; Biochemistry; Medicinal-Pharmaceutical Chemistry; Molecular Biology; Organic Chemistry; Analytical Chemistry

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Walter, L. A. (2013). A High-Throughput Screening Campaign To Discover Novel Inhibitors Of Human L-glutamine: D-fructose-6-phosphate Amidotransferase 1. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/13471

Chicago Manual of Style (16th Edition):

Walter, Lisa A. “A High-Throughput Screening Campaign To Discover Novel Inhibitors Of Human L-glutamine: D-fructose-6-phosphate Amidotransferase 1.” 2013. Doctoral Dissertation, McMaster University. Accessed January 17, 2020. http://hdl.handle.net/11375/13471.

MLA Handbook (7th Edition):

Walter, Lisa A. “A High-Throughput Screening Campaign To Discover Novel Inhibitors Of Human L-glutamine: D-fructose-6-phosphate Amidotransferase 1.” 2013. Web. 17 Jan 2020.

Vancouver:

Walter LA. A High-Throughput Screening Campaign To Discover Novel Inhibitors Of Human L-glutamine: D-fructose-6-phosphate Amidotransferase 1. [Internet] [Doctoral dissertation]. McMaster University; 2013. [cited 2020 Jan 17]. Available from: http://hdl.handle.net/11375/13471.

Council of Science Editors:

Walter LA. A High-Throughput Screening Campaign To Discover Novel Inhibitors Of Human L-glutamine: D-fructose-6-phosphate Amidotransferase 1. [Doctoral Dissertation]. McMaster University; 2013. Available from: http://hdl.handle.net/11375/13471

3. Beriault, Daniel. Investigation into the role of the hexosamine biosynthesis pathway in hyperglycemia-induced atherosclerosis.

Degree: PhD, 2014, McMaster University

Diabetes mellitus dramatically increases the risk for atherosclerotic cardiovascular disease. It has been established that chronic hyperglycemia promotes an increase in glucose flux through the hexosamine biosynthesis pathway (HBP). Central to this pathway is glutamine:fructose-6-phosphate amidotransferase (GFAT), the rate-limiting enzyme controlling the conversion of glucose to glucosamine. We have shown that glucosamine is a potent inducer of endoplasmic reticulum (ER) stress, which is characterized by the accumulation of misfolded proteins in the ER. Chronic ER stress can initiate a multifaceted response that results in lipid accumulation, inflammation and apoptosis: the hallmark features of atherosclerosis. We hypothesized that conditions of chronic hyperglycemia, associated with diabetes mellitus, can accelerate the development of atherosclerosis by a mechanism that involves increased HBP flux resulting in glucosamine-induced ER stress and the subsequent activation of pro-atherogenic pathways. In support of the hypothesis we found that glucosamine-supplemented apoE-/- mice had elevated levels of ER stress and atherosclerosis. Mechanistically, our data showed that glucosamine induced ER stress by interfering with the lipid-linked oligosaccharide biosynthesis pathway and protein N-glycosylation. These findings support a model by which conditions of hyperglycemia promote vascular complications through a glucosamine-intermediate.

Thesis

Doctor of Philosophy (PhD)

Diabetes mellitus dramatically increases the risk for heart attacks and strokes. High blood glucose is utilized in cells through its conversion into metabolites, such as glucosamine. We hypothesized that conditions of high blood glucose can led to an increase in intracellular glucosamine which can initiate pathways involved in accelerating atherosclerosis. Our results show that this is possible in both human cells and mice.

Advisors/Committee Members: Werstuck, Geoff, Biochemistry and Biomedical Sciences.

Subjects/Keywords: Diabetes; Atherosclerosis; Hexosamine biosynthesis pathway; ER Stress

…to increased flux through the hexosamine biosynthesis pathway (HBP) resulting in… …The hexosamine pathway Conditions of hyperglycemia also result in the shunting of excess… …intracellular glucose through the hexosamine biosynthetic pathway (HBP). In a typical cell… …hexosamine pathway flux has been implicated in several diabetesassociated complications including… …increased hexosamine pathway activity can promote the transcription of proinflammatory and pro… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Beriault, D. (2014). Investigation into the role of the hexosamine biosynthesis pathway in hyperglycemia-induced atherosclerosis. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/15401

Chicago Manual of Style (16th Edition):

Beriault, Daniel. “Investigation into the role of the hexosamine biosynthesis pathway in hyperglycemia-induced atherosclerosis.” 2014. Doctoral Dissertation, McMaster University. Accessed January 17, 2020. http://hdl.handle.net/11375/15401.

MLA Handbook (7th Edition):

Beriault, Daniel. “Investigation into the role of the hexosamine biosynthesis pathway in hyperglycemia-induced atherosclerosis.” 2014. Web. 17 Jan 2020.

Vancouver:

Beriault D. Investigation into the role of the hexosamine biosynthesis pathway in hyperglycemia-induced atherosclerosis. [Internet] [Doctoral dissertation]. McMaster University; 2014. [cited 2020 Jan 17]. Available from: http://hdl.handle.net/11375/15401.

Council of Science Editors:

Beriault D. Investigation into the role of the hexosamine biosynthesis pathway in hyperglycemia-induced atherosclerosis. [Doctoral Dissertation]. McMaster University; 2014. Available from: http://hdl.handle.net/11375/15401

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