HT UPLC Profiling of Total Plasma N-Glycans in Type II Diabetes Mellitus from Patients and Healthy Individuals in a Ghanaian Population Elham Memarian (Presenter) Leiden University medical centre Presenter Bio: I, Elham Memarian, am a PhD student at centre for proteomics and metabolomics in Leiden university medical centre. I was able to be a Master graduated in analytical chemistry from the faculty of chemistry at Shahid Beheshti University (Tehran, Iran). In June 2017, I started my Glysign PhD project, conducting reaserch at Genos Ltd., Zagreb, Croatia, and the Leiden University Medical Centre (LUMC) in Leiden, the Netherlands. My research is geared towards the quantification of serum protein glycosylation in diabetes.

Authors: Elham Memarian(1), Eric Adua (2), Alyce Russell(2), Irena Trbojeviæ- Akmaèiæ(1),Ivan Gudelj(1),Julija Juriæ(1),Peter Roberts(2),Gordan Lauc(1,3),Wei Wang(2,4,5)
(1)Genos Glycoscience Research Laboratory, 10000 Zagreb, Croatia (2)School of Medical and Health Sciences, Edith Cowan University, 6027, WA, Australia(3)University of Zagreb, Faculty of Pharmacy and Biochemistry, 10000 Zagreb, Croatia (4)School of Public Health, Taishan Medical University, Taian 271000, Shandong, China (5)Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing 100069, China

Aberrant protein glycosylation may reflect changes in cell metabolism of type II diabetes mellitus (T2DM) and offers fresh vistas for discovering potential biomarkers. However, the functional significance of T2DM N-glycan alterations is underexplored, since to date N-glycan profiling studies have been mainly performed in selected populations. Geographically and genetically isolated populations are needed for validation of specific biomarkers.

Introduction

Type II diabetes mellitus (T2DM) is a major health challenge worldwide, responsible for high mortality and morbidity (1-3). In fact, over one million deaths in 2015 were attributed to T2DM while the disease prevalence is still rising (3, 4). Additionally, those who survive experience the debilitating effects of co-morbidities that can lead to a decreased quality of life and productivity (5).

Glycans bind to protein backbone in a process termed glycosylation and thus far, it is regarded as the most complex and abundant co- and post-translational process in the cell.

N-glycans are a subclass of glycan types that bind to asparagine side chains of proteins in the consensus sequence Asn-X-Thr/Ser (where X is any amino acid except proline).

Although these structures are fairly stable within an individual they change under influence of an external perturbation (6,7), with different physiological parameters such as age (8), and pathophysiological conditions such as, Parkinson’s disease (9), Alzheimer’s disease (10), metabolic syndrome (11) and T2DM (12,13).

Methods

From January to June 2016, an age-gender matched cross-sectional study comprising 232 T2DM patients and 219 controls was conducted in Ghana, Western Africa. Blood plasma samples were collected for clinical assessment after which plasma N-glycans were freed, fluorescently labelled and analyzed by ultra-performance liquid chromatography (UPLC). Logistic regression was performed to determine the association between the binary outcome and N-glycan traits. Receiver operating curves (ROC) and area under the curve (AUC) were calculated.

Results

High branching (HB), di- and tri-sialylated (S2 and S3), tri-galactosylated (G3), antennary fucosylated (FUC_A) and triantennary (TA) N-glycan structures were increased in T2DM whereas low branching (LB), neutral non-sialylated glycans (S0), monogalactosylation (G1), core fucosylation (FUC_C), biantennary galactosylation (A2G) and biantennary (BA) structures were decreased compared to controls. After performing a logistic regression and adjusting for covariates and false discovery rate, 22 of the 39 N-glycans and derived traits were associated with T2DM. These were added to the fully adjusted logistic regression model yielding AUC of 90.1%.

Conclusions & Discussion

Our results show that hyperglycaemia influences N-glycan complexities among Ghanaians. Exploration in distinct populations will facilitate better prognosis and personalised treatments for T2DM.

(1) Zilliox LA, Chadrasekaran K, Kwan JY, Russell JW. Diabetes and Cognitive Impairment. Current Diabetes Reports. 2016;16(9):87.

(2) The World Health Organisation. The Diabetes epidemiolgy: World Health Organisation; 2014. Available from: http://www.who.int/mediacentre/factsheets/fs312/en/accessed 14/02/2015.

(3) International Diabetes Federation. IDF Diabetes Atlas. http://www.diabetesatlas.org/resources/2015-atlas.html, accessed, 04/10/2016. 2015.

(4) WHO. Global report on diabetes. Geneva: World Health Organisation,http://apps.who.int/iris/bitstream/10665/204871/1/9789241565257eng.pdf. accessed, 10/11/2016, 2015.

(5) Zhong Y, Lin P-J, Cohen JT, Winn AN, Neumann PJ. Cost-Utility Analyses in Diabetes: A Systematic Review and Implications from Real-World Evidence. Value Health. 2015;18(2):308-14.

(6) Gornik O, Wagner J, Puèiæ M, Kneževiæ A, Redžiæ I, Lauc G. Stability of N-glycan profiles in human plasma. Glycobiology. 2009;19(12):1547-53.

(7) Knezevic A, Polasek O, Gornik O, Rudan I, Campbell H, Hayward C, et al. Variability, heritability and environmental determinants of human plasma N-glycome. J Proteome Res. 2008;8(2):694-701.

(8) Yu X, Wang Y, Kristic J, Dong J, Chu X, Ge S, et al. Profiling IgG N-glycans as potential biomarker of chronological and biological ages: A community-based study in a Han Chinese population. Medicine. 2016;95(28):e4112.

(9) Russell AC, Šimurina M, Garcia MT, Novokmet M, Wang Y, Rudan I, et al. The N-glycosylation of immunoglobulin G as a novel biomarker of Parkinson's disease. Glycobiology. 2017;27(5):501-10.

(10) Frenkel-Pinter M, Shmueli MD, Raz C, Yanku M, Zilberzwige S, Gazit E, et al. Interplay between protein glycosylation pathways in Alzheimer’s disease. Science advances. 2017;3(9):e1601576.

(11) Lu JP, Knezevic A, Wang YX, Rudan I, Campbell H, Zou ZK, et al. Screening novel biomarkers for metabolic syndrome by profiling human plasma N-glycans in Chinese Han and Croatian populations. J Proteome Res. 2011;10(11):4959-69.

(12) Lauc G. Precision medicine that transcends genomics: Glycans as integrators of genes and environment. Biochim Biophys Acta. 2016;1860(8):1571-3.

(13) Lauc G, Pezer M, Rudan I, Campbell H. Mechanisms of disease: The human N-glycome. Biochim et Biophysica Acta (BBA)-General subjects. 2016;1860(8):1574-82.

Acknowledgments

We wish to acknowledge the immense support from the staff at the Diabetic Clinic of KATH, Kumasi. This study was supported partially by the Joint Project of the Australian National Health and Medical Research Council and the National Natural Science Foundation of China (NHMRC APP1112767-NSFC 81561128020), National Natural Science Foundation of China (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 "Croatian National Centre of Research Excellence in Personalized Healthcare" (contract No. KK.01.1.1.01.0010) and funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk³odowska-Curie grant for project GlySign (contract No. 722095).