R35GM139643

Chemoenzymatic Glycan Editing for Deciphering Biological Functions of Glycans - Project Summary/Abstract

Cell-surface glycans participate in numerous biological processes, including signal transduction, cell-cell communication, and development. Aberrant glycosylation is a hallmark of human disease. At a molecular level, glycans represent the first points of contact between cells. However, not directly encoded in the genome, these biomolecules are challenging to study using molecular biology techniques alone.

Metabolic Oligosaccharide Engineering (MOE), developed in the late 1990s, has revolutionized the way for the labeling and visualization of glycans in living organisms. In this method, cells' own glycan biosynthetic machinery is hijacked to incorporate unnatural monosaccharides with linkage promiscuity. Complementary to MOE, chemoenzymatic glycan editing has emerged as a valuable tool to probe and modify glycan structures within a cellular environment. Unlike MOE, chemoenzymatic glycan modification utilizes recombinant glycosyltransferases to transfer natural or unnatural monosaccharides with novel functions from activated nucleotide sugars to glycoconjugates on the cell surface with linkage specificity. For these reasons, chemoenzymatic glycan modification provides a facile and more precise way for probing the function of glycans in their native environments.

Building upon our successful application of chemoenzymatic glycan editing, in the next five years, we will expand our chemoenzymatic toolkits to study glycans' cellular functions with a focus on the special roles of N-Acetyllactosamine (LacNAc), fucose, and sialic acid in immune regulation. Cell-surface LacNAc mediates ligand-receptor binding and sets a threshold for initiating the downstream signaling for immune cell activation. LacNAc residues are dynamically modified by sialic acid and/or fucose. However, the specific roles of these modifications in immune regulation and disease progression remain obscure.

We are particularly interested in finding out:
(1) If changes in LacNAc and fucosylation status can serve as glycan signatures of T cell exhaustion, during which T cells gradually lose their cytokine production, proliferation, and cytotoxic capacity.
(2) Can cell-surface in situ LacNAc fucosylation be used to boost the efficacy of antitumor immunity of T cells and NK cells?

In parallel, we will develop chemoenzymatic tools for profiling sialylated glycoprotein ligands of Siglecs (sialic acid-binding immunoglobulin-type lectins) and for the identification of unnatural, high-affinity, and specific ligands to interrogate Siglec functions. Through these studies, we will gain a deeper understanding of how LacNAc, fucose, and sialic acid are involved in the regulation of immune cell activation, effector function, and exhaustion. Tools developed in this project can also be used to study other types of glycans and their interactions with glycan binding proteins.

Scripps Research Institute

THE NATIONAL INSTITUTE OF GENERAL MEDICAL SCIENCES (NIGMS) SUPPORTS BASIC RESEARCH THAT INCREASES OUR UNDERSTANDING OF BIOLOGICAL PROCESSES AND LAYS THE FOUNDATION FOR ADVANCES IN DISEASE DIAGNOSIS, TREATMENT, AND PREVENTION. NIGMS ALSO SUPPORTS RESEARCH IN SPECIFIC CLINICAL AREAS THAT AFFECT MULTIPLE ORGAN SYSTEMS: ANESTHESIOLOGY AND PERI-OPERATIVE PAIN, CLINICAL PHARMACOLOGY ?COMMON TO MULTIPLE DRUGS AND TREATMENTS, AND INJURY, CRITICAL ILLNESS, SEPSIS, AND WOUND HEALING.? NIGMS-FUNDED SCIENTISTS INVESTIGATE HOW LIVING SYSTEMS WORK AT A RANGE OF LEVELSFROM MOLECULES AND CELLS TO TISSUES AND ORGANSIN RESEARCH ORGANISMS, HUMANS, AND POPULATIONS. ADDITIONALLY, TO ENSURE THE VITALITY AND CONTINUED PRODUCTIVITY OF THE RESEARCH ENTERPRISE, NIGMS PROVIDES LEADERSHIP IN SUPPORTING THE TRAINING OF THE NEXT GENERATION OF SCIENTISTS, ENHANCING THE DIVERSITY OF THE SCIENTIFIC WORKFORCE, AND DEVELOPING RESEARCH CAPACITY THROUGHOUT THE COUNTRY.

93.859 - Biomedical Research and Research Training

National Institute of General Medical Sciences (NIGMS) [HHS - NIH]

La Jolla, California 920371000 United States

Single Zip Code

Maximizing Investigators' Research Award (R35 - Clinical Trial Optional) (PAR-19-367)

Amendment Since initial award the total obligations have increased 412% from $783,616 to $4,015,088.