Glycosylation is an important post-translational modification of proteins and lipids. This process controls cell recognition and signaling processes that regulate human development, immunity and disease. The current proposal aims to develop Systems Biology based computational and experimental methodologies to enhance our understanding of cellular glycosylation pathways. In particular, our focus is on better understanding the features that regulate the formation of O-linked glycans on human leukocytes. By binding adhesion molecules belonging to the selecting family, these O-glycans play a critical role in regulating leukocyte adhesion to vascular endothelial cells that line blood vessel walls at sites of inflammation and cardiovascular disease. Our overall hypothesis is that "In silico modeling of glycosylation reaction networks can identify rate limiting steps that control the formation of selectin-ligands on human leukocytes. Defined and specific perturbation of these rate-limiting steps can reduce leukocyte-endothelial cell adhesion/migration in vivo during inflammation." The specific aims are: 1) to develop computational models to predict the rate-limiting steps that control cellular glycosylation. 2) To quantify the role of selected glycosyltransferases and the peptide backbone in regulating O-linked glycosylation and leukocyte selecting-binding function. 3) To test the effect of silencing glycosyltransferases on leukocyte retention in the bone marrow, and cell migration to sites of inflammation. The project involves collaboration between investigators with expertise in Systems Biology based modeling, quantitative bioengineering experimentation, proteomics, glycobiology, immunology and animal models. Experimental studies span multiple scales from genes, to proteins/enzymes, to carbohydrate structure and cell adhesion function, both in vitro and in vivo. The computer modeling integrates this information to determine the effect of system perturbation on glycan structure and function. Expected project outcomes include: I) Definition of a new standard called GlycoML for the description of glycosylation reaction networks. ii) Combined use of experiment and theory to reveal potential intra-cellular/metabolic targets of glycosylation that can quantitatively and definitively alter selectin-ligand structures. iii) Definition of the precise a (2, 3)sialyltransferase(s) and a (1, 3) fucosyltransferases(s) that regulate selectin-ligand biosynthesis in human leukocytes. iv) Improved understanding of the role of the peptide backbone in regulating O-glycosylation chain initiation, extension and termination. v) Validation in animal models of inflammation, peritonitis and COPD (chronic obstructive pulmonary disease), key hypothesis generated using computer simulation and ex vivo experimentation.
Half of all proteins in nature are decorated/ modified by sugar structures that are called glycans, and these play an active role in regulating cell/tissue function during normal human development and during disease. The current proposal develops novel systems-level computational and experimental tools that will enhance our understanding of how nature regulates the structure of glycans. Such understanding will aid the identification of new strategies to control glycan structures and to reduce white blood cell adhesion at sites of human inflammatory disease.
|Liu, Gang; Neelamegham, Sriram (2014) A computational framework for the automated construction of glycosylation reaction networks. PLoS One 9:e100939|
|Patil, Shilpa A; Bshara, Wiam; Morrison, Carl et al. (2014) Overexpression of ?2,3sialyl T-antigen in breast cancer determined by miniaturized glycosyltransferase assays and confirmed using tissue microarray immunohistochemical analysis. Glycoconj J 31:509-21|
|Nouri-Nigjeh, Eslam; Sukumaran, Siddharth; Tu, Chengjian et al. (2014) Highly multiplexed and reproducible ion-current-based strategy for large-scale quantitative proteomics and the application to protein expression dynamics induced by methylprednisolone in 60 rats. Anal Chem 86:8149-57|
|Tu, Chengjian; Mammen, Manoj Jacob; Li, Jun et al. (2014) Large-scale, ion-current-based proteomics investigation of bronchoalveolar lavage fluid in chronic obstructive pulmonary disease patients. J Proteome Res 13:627-39|
|An, Bo; Zhang, Ming; Qu, Jun (2014) Toward sensitive and accurate analysis of antibody biotherapeutics by liquid chromatography coupled with mass spectrometry. Drug Metab Dispos 42:1858-66|
|Tu, Chengjian; Li, Jun; Sheng, Quanhu et al. (2014) Systematic assessment of survey scan and MS2-based abundance strategies for label-free quantitative proteomics using high-resolution MS data. J Proteome Res 13:2069-79|
|Nouri-Nigjeh, Eslam; Zhang, Ming; Ji, Tao et al. (2014) Effects of calibration approaches on the accuracy for LC-MS targeted quantification of therapeutic protein. Anal Chem 86:3575-84|
|Madabhushi, Sri R; Zhang, Changjie; Kelkar, Anju et al. (2014) Platelet GpIba binding to von Willebrand Factor under fluid shear:contributions of the D?D3-domain, A1-domain flanking peptide and O-linked glycans. J Am Heart Assoc 3:e001420|
|Gui, Shanying; Gathiaka, Symon; Li, Jun et al. (2014) A remodeled protein arginine methyltransferase 1 (PRMT1) generates symmetric dimethylarginine. J Biol Chem 289:9320-7|
|Lo, Chi Y; Antonopoulos, Aristotelis; Dell, Anne et al. (2013) The use of surface immobilization of P-selectin glycoprotein ligand-1 on mesenchymal stem cells to facilitate selectin mediated cell tethering and rolling. Biomaterials 34:8213-22|
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