N-Glycosylation Profiles As a Risk Stratification Biomarker for Type II Diabetes Mellitus and Its Associated Factors

N-Glycosylation Profiles As a Risk Stratification Biomarker for Type II Diabetes Mellitus and Its Associated Factors

Edith Cowan University Research Online Theses: Doctorates and Masters Theses 2018 N-Glycosylation profiles as a risk stratification biomarker for Type II Diabetes Mellitus and its associated factors Eric Adua Edith Cowan University Follow this and additional works at: https://ro.ecu.edu.au/theses Part of the Analytical, Diagnostic and Therapeutic Techniques and Equipment Commons, and the Endocrinology, Diabetes, and Metabolism Commons Recommended Citation Adua, E. (2018). N-Glycosylation profiles as a risk stratification biomarker for Type II Diabetes Mellitus and its associated factors. https://ro.ecu.edu.au/theses/2162 This Thesis is posted at Research Online. https://ro.ecu.edu.au/theses/2162 Edith Cowan University Copyright Warning You may print or download ONE copy of this document for the purpose of your own research or study. The University does not authorize you to copy, communicate or otherwise make available electronically to any other person any copyright material contained on this site. You are reminded of the following: Copyright owners are entitled to take legal action against persons who infringe their copyright. A reproduction of material that is protected by copyright may be a copyright infringement. Where the reproduction of such material is done without attribution of authorship, with false attribution of authorship or the authorship is treated in a derogatory manner, this may be a breach of the author’s moral rights contained in Part IX of the Copyright Act 1968 (Cth). Courts have the power to impose a wide range of civil and criminal sanctions for infringement of copyright, infringement of moral rights and other offences under the Copyright Act 1968 (Cth). Higher penalties may apply, and higher damages may be awarded, for offences and infringements involving the conversion of material into digital or electronic form. N-GLYCOSYLATION PROFILES AS A RISK STRATIFICATION BIOMARKER FOR TYPE II DIABETES MELLITUS AND ITS ASSOCIATED FACTORS Submitted for the Degree of Doctor of Philosophy Eric Adua BSc (Hons), MSc Edith Cowan University School of Medical and Health Sciences 2018 Supervisors Professor Wei Wang MD, PhD, FFPH, FRSM, FRSB Associate Professor Peter Roberts BSc (Hons), PhD DECLARATION I certify that this thesis does not, to the best of my knowledge and belief: (i) incorporate without acknowledgement any material previously submitted for a degree or diploma in any institution of higher education; (ii) contain any material previously published or written by another person except where due reference is made in the text; or (iii) contain any defamatory material. (iv) I also grant permission for the Library at Edith Cowan University to make duplicate copies of my thesis as required. Signed…………………………………………….. Date…13 December 2018…………………………… i USE OF THESIS The Use of Thesis statement is not included in this version of the thesis. ABSTRACT Worldwide, the prevalence of cardiometabolic diseases, particularly type II diabetes mellitus (T2DM), and to a lesser extent, metabolic syndrome (MetS), has increased dramatically. Despite this increase, there is still a lack of robust biomarkers for cardiometabolic diseases to secure better clinical outcomes. The enzymatic attachment of oligosaccharides (glycans) to proteins-glycosylation is of metabolic and physiological significance, as exploring aberrations of glycosylation profiles can reveal novel biomarkers. In parallel, this process could also explain the biological mechanisms that underpin a suboptimal health status (SHS), a reversible subclinical stage of a cardiometabolic disease. However, studies on the correlation between glycosylation and MetS/T2DM are scarce and none has thus far been performed on a West African population. Thus, the overall aim of this thesis was to explore complementary biomarker panels of healthy and diseased patients considered relevant to Ghanaian residents. The thesis is structured in the form of five related studies, each addressing a specific aim. From January 2016 to October 2016, a longitudinal case-control study comprising 253 T2DM patients and 260 controls, aged 18-80 years was conducted in Ghana. Fasting plasma samples were collected for clinical assessment, after which plasma N-glycans were analysed by Ultra-Performance Liquid Chromatography (UPLC) and statistical analyses performed. Central adiposity, underweight, high systolic blood pressure (SBP), high diastolic blood pressure (DBP) and high triglycerides (TG) were found to be independent risk factors associated with high SHS after adjusting for age and gender (Study I). SHS score was associated with age, physical inactivity, fasting plasma glucose (FPG), TG and MetS. MetS was associated with increased high branching (HB), trigalactosylated (G3), antennary fucosylated (FUC_A), triantennary (TRIA) and decreased low branching (LB) glycan structures (Study II). The levels of HB, G3, FUC_A, and TRIA N-glycans were increased in T2DM whereas levels of LB, non-sialylated (S0), monogalactosylation (G1), core fucosylation (FUC_C), biantennary galactosylation (A2G) and biantennary (BA) N- glycans were decreased compared to controls (Study III). Biguanides alone, or in combination with sulfonylurea and thiazolidinedione, did not improve glycaemic status at follow-up. Many participants using angiotensin converting enzyme inhibitors achieved desired targets for blood pressure control while statins were effective for control of plasma lipids (Study IV). At a population level, the variability of N-glycan structures ranged from 11% to 56% at both baseline and follow-up, with an average coefficient of variation of iii 28% and 29%, respectively. The intra-individual N-glycan peak (GP) variations were minor except for GP1 and GP29. However, there were no statistically significant differences in N-glycosylation profiles from baseline to follow-up (Study V). This thesis shows an association between SHS and MetS/T2DM while MetS and T2DM are characterised by increased levels of complex N-glycan structures, and these structures are stable in T2DM over six months. Many of the findings in this thesis agree with earlier studies from Chinese and Croatian populations with major differences attributed to genetic and environmental factors. Future longitudinal studies are required to provide a better understanding of the transition from SHS to T2DM, as well as to validate N-glycans as generic risk stratification biomarkers for a general population. iv Acknowledgements Firstly, I will like to express my sincere appreciation to my principal supervisor, Professor Wei Wang, and co-supervisor, Associate Professor Peter Roberts, for their immense and continuous support throughout the PhD journey. Their advice, comments and encouragement were instrumental to completing this thesis. To my colleague, Alyce Russell, I say thank you for the immeasurable support you provided me over the past years. I thank my teammates: Enoch Odame Anto, Xingang Li, Hao Wang, Siqi Ge, and Xueqing Wang for their discussions and contributions to my work. To all other colleagues in the PhD suite of building 21, I say thank you. I wish to thank our collaborators at Genos Glycoscience Research Laboratory, Zagreb, Croatia for performing the N-glycan analysis. My sincere appreciation also goes to the staff of the Diabetes Clinic of the Komfo Anokye Teaching Hospital (KATH). In particular, I will like to thank Dr Osei Sarfo Kantanka, Dr Fred Stephen Sarfo, Mrs Agnes, Shadrach, Gideon, amongst others, for their immense support during the data collection phase of this work. I sincerely thank Dr Albert Dompreh for his advice and giving me space to store my samples. My profound gratitude goes to the participants, both T2DM sufferers and healthy controls, for not only giving their medical and demographic information, but also providing blood samples for analyses. Special appreciation also goes to Dr Samuel Asamoah Sakyi, Associate Professor Francis Agyemang Yeboah, Dr William KBA Owiredu, Dr Edwin Ferguson Laing and the entire staff at the Department of Molecular Medicine of the Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. My heartfelt thanks goes to Dr Kwasi Frimpong for his encouragement, advice and support throughout my stay in Australia. In addition, I thank Dr Francis Atta Kuranchie and Isabella Kuranchie, Dr Daniel Doe, Dr Esther Adama and Dr Emmanuel Aboagye for their encouragements. To Mr. Kwaafo Awuah Mensah, Mr Wilfred Sefah, Mr. Isaac Kosi, Mr. Hayford Ofori, Mrs Mary Afi Mensah and Mr. Yakubu Sumaila, I say thank you for your motivation, encouragement and company. Further, I thank Mrs Joanne Hoffsten for being a mother and given me overwhelming care, support and advice. To Mr. Joseph Sim of the Graduate Research School (GRS), I say thank you for your timely advice and your willingness to talk to me anytime I approached you. Finally, I thank Dr Amanda Harris, communication adviser (GRS), for proofreading parts of my manuscripts and helping me to improve on my writing skills. v Source of Funding This project was supported partially by the Joint Project of the Australian National Health & Medical Research Council and the National Natural Science Foundation of China (NHMRC APP1112767-NSFC 81561128020), National Natural Science Foundation of China (81771207, 81370083, 81673247, 81573215), Edith Cowan University Collaboration Enhancement Scheme 2017 (Round 1), the National Key Technology Support Program of China (2012BAI37B03); as well as by funding from the European Structural and Investments funds for project

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