Decoding the glycan forms of glycoRNA-L and glycoRNA-S from leukocytes

About This Grant

Project Summary In mammalian cells, RNAs are predominantly located within cytoplasm and nucleus. A recent study, however, has reported that RNAs can be glycosylated, and such glycosylated RNAs (called glycoRNAs) are localized on out cell surface. The glycoRNAs are glycan-modified small non-coding RNAs. These RNAs are transcribed and maturated in nucleus and transported to cytoplasm for processing and then conjugated with glycan chains in endoplasmic reticulum. The conjugated molecules are then transported to cell membrane and anchored on cell membrane by binding to transmembrane RNA binding proteins. The cell surface glycoRNAs can serve as ligands or receptors to mediate cell-cell interaction, communication and infiltration and may also trigger cell signal transductions. Our recent works suggest that there were two forms of glycoRNAs, named glycoRNA-L and glycoRNA-S, robustly expressed in leukocytes, but not non-immune cells. GlycoRNA-L was migrated with ~11 kb RNA, whereas glycoRNA-S was migrated with ~0.6 kb RNAs. Using RNase removed the RNA frag- ments, the migration of both glycoRNA-L and glycoRNA-S was slightly faster, suggesting that the migration of glycoRNA-L and glycoRNA-S was determined by the glycan chains, but not RNA fragments. Further studies suggest that the glycan structures and functions of glycoRNA-L and glycoRNA-S may be distinguished. How- ever, the compositions and structures of glycan forms of glycoRNA-L and glycoRNA-S remain unknown. We hypothesize that the glycoforms of glycoRNA-L and glycoRNA-S from leukocytes are determinants of their functional significance. The goal of this proposal is to decode the compositions and structures of glycan forms of glycoRNA-L and glycoRNA-S from leukocytes. We will reach this goal by two approaches: 1) metabolic labeling combined with enzymatic digestion; 2) glycoRNA-L and glycoRNA-S purification and LC/MS analysis. Completion of the project will significantly advance our understanding of the role and mechanisms of glycoRNA- L and glycoRNA-S in the regulation of immune response and immune-related human diseases. The study will also provide a method for mapping the glycan structures of glycoRNAs from other cells such as cancer cells, which may provide insights for generating innovative diagnostic and therapeutic strategies.