The role of cell surface RNAs in neutrophils

PROJECT SUMMARY In mammalian cells, RNAs are predominantly located within the cytoplasm and nucleus. A recent study, however, has found that RNAs can be glycosylated, and a fraction of such glycosylated RNAs (referred to as glycoRNAs) are located on the outer cell surface. As outer cell surface represents a different topological space compared to cytoplasm and nucleus, these exciting findings raise important questions on the functions of cell surface RNAs, their precise chemical nature, their mechanisms of action, and mechanisms of their presence on the cell surface, all of which are not known. This proposal focuses on neutrophils, an important hematopoietic cell type that play important innate immune functions and are often the first responders toward inflammation and tissue damage. While the circulation half-lives of neutrophils are relatively short, neutrophils can migrate from circulation into tissues, a process that involves complex interactions with the endothelial cell layer lining the blood vessels. Glycan-binding lectins and integrins are known players in neutrophil-endothelium interactions, but the whole process remains incompletely understood. Based on our preliminary data, we propose the existence of glycoRNAs on neutrophil cell surface and aim to test that neutrophil cell surface RNAs mediate important functions of neutrophils including their interaction with endothelial cells. With a team of investigators of complimentary expertise, we will achieve these goals through four specific aims to decipher the molecular nature, functions, and mechanisms of neutrophil cell surface RNAs. Successful execution of our proposed project will add a new dimension to the regulation of neutrophil functions by studying a new class of RNA-containing regulators. The proposed experiments will also address key questions regarding glycoRNAs. As the field of cell surface RNA/glycoRNA is at its infancy, there are many exciting questions that cannot be explored in this single proposal, but findings from this proposal could stimulate both future explorations and the community toward better understanding of glycoRNAs in neutrophils and in other diverse biological settings.