Abstract:Glycomics: One of the most important aspects for the comprehensive understanding of the life foundation

Abstract:As one of the most common and important protein modifications, glycosylation has been one of the focuses of the proteomic researches. In the last decades, most of N-linked glycoproteomic studies focused mainly on the analysis of either released glycans or de-glycosylated peptides. While this strategy reduced the complexity of glycoprotein analysis, it lost glycosite-specific glycosylation information. Several strategies and methods for intact N-glycopeptide analysis have been established during the last few years. Generally, to achieve the identification and quantification of intact glycopeptides, the first step is to enrich glycopeptides from complex samples to reduce the affects from non-glycosylated peptides, then the mass spectrometry parameter settings need to be adjusted to satisfy the fragment features of glycopeptides, importantly the related software also need to be developed for the precise identification of the peptide sequence and glycan structures or compositions of the intact glycopeptides. These three main aspects of the strategies for mass spectrometry-based intact glycopeptide analysis are discussed in this paper. Some further details, such as the recognition of intact glycopeptide spectra, precursor monoisotopic mass correction, database selection, as well as the false discovery rate (FDR) evaluation and control, are further discussed. Direct intact glycopeptide analyses, with the recovery of the glycosite-specific glycosylation information, will provides a powerful tool for biomarker discovery and the mechanism studies on various diseases.

Abstract:Glycomics research plays an important role in life sciences and biomedicine industry. Oligosaccharide structure identification is one of the important research topics of glycomics. The development of high-throughput mass spectrometry technology in recent decade contributes significantly to oligosaccharide structure identification. In this review, we introduced the research background of tandem mass spectrometry assisted glycan structure identification. Then, we reviewed the current strategies used for glycan identification and analyzed the key technologies of existing methods. Finally, we summarized the advantages and disadvantages of the existing methods. The outlook on utilization of tandem mass spectrometry to assist oligosaccharide structure identification is also discussed.

Abstract:Glycomics represents a novel omics technology developed after the genomics and proteomics, which focus on the glycan structure and function．As a group of biomolecule, glycans provide and store energy within the cell, and play many significant roles in physiological and pathological processes, such as cell-cell recognition and inflammatory and autoimmune diseases．Structural analysis of glycan is the bottleneck of glycomics research, due to their macro-heterogeneity (site occupancy) and micro-heterogeneity (different glycoforms attached to one glycosylation site). Comparing with traditional analysis approaches, mass spectrometry has become the method of choice for structural analysis methods in glycan, thanks to its ability to require minute amounts of sample, gain more different information and to be used in combination with high-throughput analysis methods. This paper summarizes the advance in our understanding of glycan structures using mass spectrometry (MS), including multistage mass spectrometry (MSⁿ), LC-MS and CE-MS.

Abstract:Extracellular vesicles (EVs) are a kind of membrane-bound particles with diameters ranging from 20 to 1 000 nm which can be uptaken by recipient cells. More and more research have focused on biological functions of EVs in disease diagnose, prognosis and drug delivery. It has been proved that EVs participate in cell-cell communication and material transfer directly. Nucleic acids(mRNA, microRNA and lncRNA)and proteins contained in EVs have significant influences on the behaviors of target cells. The surface of EVs is covered by glycoconjugates such as proteoglycans, glycosphingolipids and glycoproteins. And these glycoconjugates are directly associated with cell-cell adhesion, cell-cell communication, cell-matrix interactions, immune modulation, metastasis formation and others. This review summarizes the recent research progress of glycoconjugates on Evs, and is helpful to extensively understand the effects of glycosylation in the process of EVs’ biosynthesis, release and transport and EVs’biological functions.

Abstract:CA125 is a gold standard for the diagnosis of ovarian cancer, however, its specificity is still relatively low in clinical application. Tumor formation and development process is often accompanied by abnormal glycosylation modification and changes in glycan structures. The different tumors have specifically abnormal glycan structures. In recent years, the technologies in glycoproteomics and glycomics, such as lectin microarrays and multiple mass spectrometry, are used to discover the small discrepancies of N- and O-linked glycan structures in CA125 of the different sources. These abnormal glycan structures could increase the specificity of CA125 for the diagnosis of ovarian cancer. In the past decade, the technologies of glycome were also used to directly analyze the subtle glycan structures in the serum and body fluid (ascites, vesicle fluid, etc.) from patients with ovarian cancer. The results showed that the N-linked glycan structures can effectively identify ovarian cancer patients and healthy volunteers, which may be new biomarkers with better sensitivity and specificity for the diagnosis of ovarian cancer. Trends in the development of biomarkers for ovarian cancer shifted from qualitative and quantitative studies of proteins, to identification and quantitative analysis of glycosylation modification and glycan structures of biomarkers. Taking the perspective of glycomics, the status and development trend of ovarian cancer biomarkers are reviewed and discussed in this paper.

Abstract:Protein glycosylation modification includes N-linked glycosylation, O-linked glycosylation and glycosylphosphatidylinositol anchor glycosylation. Difference from nucleic acids and proteins, the synthetic process of glycans is mainly completed by a series of glycosyltransferases which catalyze glucosidic bond, not followed the traditional central dogma of genetic information transmission. Abnormal glycosylation modification is considered to be closely related to the occurrence, development and clinical prognosis of malignant tumor. Previous studies have shown that the abnormity of glycosyltransferases expression and glycans structure affects key steps of the metastatic cascade, such as epithelial-mesenchymal-transition (E-cadherin, N-cadherin) , cell motility (integrin β1 and α5), invasion (matrix-metalloproteinases), extravasation (sLex and sLea), which by regulating the interaction between tumor cells and extracellular matrix. In this review, we mainly focus on the structures and biological functions of three glycosyltransferase families (sialyltransferases, fucosyltransferases and N-acetylglucosaminyltransferases), and their roles in tumor metastasis, hoping it can provide new ideas for the prognosis and diagnosis in tumor metastasis.

Abstract:Complement system is an essential part of the innate immunity which serves as a bridge between innate and adaptive immunity. The complement system comprises of over 30 different proteins, most of which are glycoproteins. The recent researches have shown that complement system plays important roles in defense against the evading microbes and maintaining the cellular hemostasis. However, the complement system requires firm controls. Either insufficient activation or over-activation of complement would cause diseases. In this review, we summarize the recent advances in understanding the activation, regulation and the function of complement system and for the first time review the complement system by its glycosylation: we summarize the glycan structures of the complement proteins and analyze the glycosylation impact on the function of the proteins.

Abstract:The glycosylation modification of virus structural protein is implicated in virus replication and virus invasion of host cells. For host, in virus infection and host antiviral processes, the host glycosylation process can, on the one hand, inhibit virus replication and invasion, on the other hand promote the virus infection of the host. For virus, as virus lacks glycosylation modification system, viral glycosylation modification process exploits the synthesis system of the host cells. The glycosylation modification of virus plays an important role in viral protein folding, virus infection and invasion of the host, virus recognition of host cell receptors, and is involved in virus immune escape. With the development of glycosylation investigation technology, glycosylation-based functional applications are becoming more and more intensive: such as the development of new viral vaccines and novel antiviral drugs, mass spectrometry and bioinformatic techniques based on glycoprotein proteomics studies, and the application of glycosylation for viral disease diagnosis and treatment, which lay the foundation for further development of glycosylation research. Here we reviewed the virus and host cell glycosylation modification and its related functions and its application.

Abstract:The study on tissue development and regeneration is one of the hot spots of life science. Zebrafish has become one of the popular model organisms due to its rapid growth rate, transparent embryos which is easy to observe, and the capacity to regenerate fin, heart, nervous system, etc. During the development and regeneration process of zebrafish, cell proliferation, differentiation, morphogenesis and other metabolic activities occurs，but little is known about the regulatory mechanism among such complex dynamic processes to us. Further studies on these processes have magnificent meanings, for instance, laying a theoretical foundation for the treatment of many diseases, and also promoting the progress of tissue engineering. Previous study has shown that multifold proteins involved in the regulation of tissue development and regeneration. Protein glycosylation is an important post-translational modification, which can affect cell recognition, adhesion, and signal transduction, even lead to inflammation, cancer and other malignant diseases. In recent years, the development of glycomics provides new ideas for developmental biology and regenerative medicine. In this present review, we summarize the role of glycosylation alteration in the development process of zebrafish, and prospect for its future study on regeneration.

Abstract:The phenomenon of protein O-GlcNAcylation has been discovered for more than 30 years. In animals, O-GlcNAcylation plays important roles in cellular signaling transduction, gene transcription, epigenetic, metabolism regulation and etc. While the functions of O-GlcNAcylation in plants is remain unclear, and only few studies were reported in recent years. In this review paper, the research advances on plants O-GlcNAcylation were reviewed, including UDP-GlcNAc biosynthesis pathway, the key enzymes in O-GlcNAc modification pathway, the detection and function analysis of O-GlcNAc modified proteins. These works revealed that O-GlcNAcylation has essential functions in plant growth and development, plant hormone networks regulation, signal transduction and plant virus infection process. This article will facilitate the subsequent research on the O-GlcNAcylation in plants.

Abstract:Ribosome-inactivating proteins (RIPs) are a class of cytotoxic enzymes which possess highly specific rRNA N-glycosidase activity and are capable of catalytically inactivating prokaryotic or eukaryotic ribosomes. Due to their unique biological activities, RIPs have been considered to have great potential in medical and agricultural applications. The cucumber genome accommodates two genes encoding type 2 ribosome-inactivating proteins, further referred to as CumsaAB1 and CumsaAB2. Type 2 RIPs, represented by ricin, usually consist of two peptides linked by a disulfide bridge. A chain with N-glycosidase activity and B chain with carbohydrate-binding activity. In this study, the expression of the cucumber RIPs was analyzed. Sequence analysis showed that CumsaAB1 is synthesized with a signal peptide and subcellular localization studies further confirmed that the protein is expressed extracellularly, following the secretory pathway. Analyses of the transcript levels in various tissues during cucumber development showed that CumsaAB1 is present at extremely low levels in most tissues while the expression of CumsaAB2 is much higher, especially in leaves from plants at first-true-leaf stage and plants at the onset of flowering. Molecular modelling of the RIP sequences was performed to unravel the three-dimensional conformation of cucumber RIPs and their carbohydrate-binding sites. This study provided valuable information on the subcellular localization, the tissue-specific expression and the structure of RIPs from cucumber plants.

Abstract:Milk oligosaccharides, which are free oligosaccharides in the mammalian milk, is one of the main composition in milk. Recent studies suggested that milk oligosaccharides improved immune function, and showed prebiotics as well as anti-infection actives. Milk oligosaccharides is also important for the intestinal development, neural development of infants. Buffalo (Bubalus bubalis) milk is the second important milk source besides cow milk. It was also well accepted that buffalo milk was rich in nutritional content and was a high quality dairy product with good taste. However, researches on buffalo milk oligosaccharides was limited and only worked on American buffalo. On the other hand, milk oligosaccharides on Chinese buffalo is lacking. In the present study, colostrum milk samples from Guangxi buffalo were purified with solid phase extraction and modified by Aniline (Bn) derivative reagent. The sample was further purified by UPLC-ESI-Q-TOF-MS. The oligosaccharide components in buffalo colostrum were determined and compared with the cow colostrum milk. 19 kinds of oligosaccharides were found in cow colostrum and 9 in buffalo colostrum. Moreover, in both two kinds of colostrum, neutral disaccharide m/z 385.15, neutral trisaccharide m/z 547.21 and acidic oligosaccharide m/z 635.23 were the main composition. In general, the proportion of neutral oligosaccharides in buffalo milk was higher than that in cow milk, with a ratio of 88.88% and 63.16%, respectively.