The Human Lung Glycome Reveals Novel Glycan Ligands for Influenza A Virus

Nan Jia,Chao Gao,Lauren Byrd-Leotis,David A Steinhauer,Yasuyuki Matsumoto,Richard D Cummings,Jacob E Kohlmeier,Alexander N Wein,Jenna L Lobby

doi:10.1038/s41598-020-62074-z

Abstract

Glycans within human lungs are recognized by many pathogens such as influenza A virus (IAV), yet little is known about their structures. Here we present the first analysis of the N- and O- and glycosphingolipid-glycans from total human lungs, along with histological analyses of IAV binding. The N-glycome of human lung contains extremely large complex-type N-glycans with linear poly-N-acetyllactosamine (PL) [-3Galβ1–4GlcNAcβ1-]n extensions, which are predominantly terminated in α2,3-linked sialic acid. By contrast, smaller N-glycans lack PL and are enriched in α2,6-linked sialic acids. In addition, we observed large glycosphingolipid (GSL)-glycans, which also consists of linear PL, terminating in mainly α2,3-linked sialic acid. Histological staining revealed that IAV binds to sialylated and non-sialylated glycans and binding is not concordant with respect to binding by sialic acid-specific lectins. These results extend our understanding of the types of glycans that may serve as binding sites for human lung pathogens.

Highlights

It is important to define human glycans for their roles in systems biology, but to discern the potential attachment sites and ligands for many infectious organisms and viruses
We focused on the analysis of N- and O-glycans released from glycoproteins as well as glycosphingolipid (GSL)-derived glycans that were extracted from a perfused lung of a healthy young adult, the results of which are compared to a lung from a second donor
Sambucus nigra agglutinin (SNA), which detects the expression of α2,6-linked sialic acid, bound a wide range of proteins and the staining was not affected by neuraminidase S digestion, which hydrolyses α2,3-linked sialic acids (Fig. 1c)

Summary

Introduction

It is important to define human glycans for their roles in systems biology, but to discern the potential attachment sites and ligands for many infectious organisms and viruses. Current understanding of the human lung glycome remains at the tissue level with limited information obtained from lectin staining and mass spectrometric analyses of surgical biopsies from human lungs[21,22,23]. Our recent studies using shotgun glycomics of total N-glycans of a human lung challenge the paradigm of sialic acid recognition, as we discovered many IAVs recognize phosphorylated glycans[24]. We present our analyses of the human lung glycome using mass spectrometry (MS), with complementary information generated by Western blot and histochemistry staining with anti-glycan antibodies, lectins and IAVs. We focused on the analysis of N- and O-glycans released from glycoproteins as well as glycosphingolipid (GSL)-derived glycans that were extracted from a perfused lung of a healthy young adult, the results of which are compared to a lung from a second donor. This work represents a major step in the goals of the Human Glycome Project, which aims to define the structures and functions of human glycoconjugates (www.human-glycome.org)

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Results

Conclusion