Mucins, highly glycosylated proteins, are the main macrocomponents of the mucus layer that protects our epithelia from toxins, allergens and pathogens under physiological conditions. Tight regulation of their synthesis is essential for the correct organization and protective role of the mucus layer. Accordingly, altered mucins’ properties or quantities are the hallmarks of several human pathologies, such as ulcerative colitis, asthma or colorectal cancer. Here, we will discuss mucins’ biosynthesis, trafficking, secretion, and how altered glycosylation on mucins, specifically modified by Fucosyltransferase 8 (FUT8), affects the rheological properties of the mucus and contributes to the development of the mucinous colonic disease called Ulcerative colitis.

Proteoglycans are complex glycoconjugates consisting of one or more glycosaminoglycan chains that are covalently attached to a core protein. Research on glycosaminoglycan chains and proteoglycans can be traced back to the early 20th century. There have been many reports on the extraction of proteoglycans from animal cartilage tissues, and the structures of proteoglycans have previously been elucidated. Proteoglycans in cartilage are called aggrecan. They consist of a core protein with many attached glycosaminoglycan chains. Recently, several new simple methods have been developed for the extraction of large amounts of aggrecan. This study focuses on the development of simple extraction methods for proteoglycans and introduces one of the simple extraction methods that I have developed: the extraction of proteoglycans using umezu (a byproduct of the pickling process for the mume fruit).

Glycosylation is one of the major post-translational modifications of antibodies. Certain glycans of therapeutic antibodies affect biological activities, and the glycan is one of the structural characteristics that can be a candidate critical quality attribute of therapeutic antibodies. Because the glycan structure changes depending on the type of cell substrate and culture conditions, it is required that the glycan profile be analysed in detail beginning in the early stages of development. Although a method combining fluorescent labeling and liquid chromatography is well-established as a glycan analytical method for therapeutic antibodies, a new method using high-resolution accurate mass spectrometer called multi-attribute method (MAM) has been attracted increased amounts of attention in recent years. In this review, we outline the characteristics of the glycans of therapeutic antibodies and the glycan analysis using MAM.

N-linked glycans, including high-mannose-, complex-, and hybrid-type glycans, play key roles in various biological processes. Specifically, high-mannose-type glycans, including tetradecasaccharides (G3M9) consisting of three D-glucose (Glc), nine D-mannose (Man), and two N-acetyl-D-glucosamine (GlcNAc) residues, are essential for glycoprotein synthesis. Several high-mannose-type glycans obtained from G3M9-glycan using various glycan-processing enzymes function as regulatory signals for glycoprotein folding, secretion, and degradation. These properties highlight the importance of high-mannose-type glycans in cells. Notably, chemical biologists in the fields of glycoscience and glycotechnology have synthesized all high-mannose-type glycans and their derivatives, thereby contributing to the elucidation of the precise specificities of high-mannose-type glycan-related proteins in vitro. Chemically synthesized glycan probes are important to understand glycoprotein folding, secretion, and degradation at the molecular level. Therefore, in this review, we summarize the recent progress in the chemical synthesis approaches for high-mannose-type glycans and discuss the potential of target-specific glycan probes designed and synthesized based on the findings from functional analysis of high-mannose-type glycans.

Proteoglycans are complex glycoconjugates consisting of one or more glycosaminoglycan chains that are covalently attached to a core protein. Research on glycosaminoglycan chains and proteoglycans can be traced back to the early 20th century. There have been many reports on the extraction of proteoglycans from animal cartilage tissues, and the structures of proteoglycans have previously been elucidated. Proteoglycans in cartilage are called aggrecan. They consist of a core protein with many attached glycosaminoglycan chains. Recently, several new simple methods have been developed for the extraction of large amounts of aggrecan. This study focuses on the development of simple extraction methods for proteoglycans and introduces one of the simple extraction methods that I have developed: the extraction of proteoglycans using umezu (a byproduct of the pickling process for the mume fruit).

Glycosylation is one of the major post-translational modifications of antibodies. Certain glycans of therapeutic antibodies affect biological activities, and the glycan is one of the structural characteristics that can be a candidate critical quality attribute of therapeutic antibodies. Because the glycan structure changes depending on the type of cell substrate and culture conditions, it is required that the glycan profile be analysed in detail beginning in the early stages of development. Although a method combining fluorescent labeling and liquid chromatography is well-established as a glycan analytical method for therapeutic antibodies, a new method using high-resolution accurate mass spectrometer called multi-attribute method (MAM) has been attracted increased amounts of attention in recent years. In this review, we outline the characteristics of the glycans of therapeutic antibodies and the glycan analysis using MAM.

N-linked glycans, including high-mannose-, complex-, and hybrid-type glycans, play key roles in various biological processes. Specifically, high-mannose-type glycans, including tetradecasaccharides (G3M9) consisting of three D-glucose (Glc), nine D-mannose (Man), and two N-acetyl-D-glucosamine (GlcNAc) residues, are essential for glycoprotein synthesis. Several high-mannose-type glycans obtained from G3M9-glycan using various glycan-processing enzymes function as regulatory signals for glycoprotein folding, secretion, and degradation. These properties highlight the importance of high-mannose-type glycans in cells. Notably, chemical biologists in the fields of glycoscience and glycotechnology have synthesized all high-mannose-type glycans and their derivatives, thereby contributing to the elucidation of the precise specificities of high-mannose-type glycan-related proteins in vitro. Chemically synthesized glycan probes are important to understand glycoprotein folding, secretion, and degradation at the molecular level. Therefore, in this review, we summarize the recent progress in the chemical synthesis approaches for high-mannose-type glycans and discuss the potential of target-specific glycan probes designed and synthesized based on the findings from functional analysis of high-mannose-type glycans.