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Recent studies have elucidated that expression of certain glycoproteins in human saliva is increased or decreased according to age; meanwhile, human saliva may inhibit viral infection and prevent viral transmission. However, little is known about the age- and sex-associated differences in the glycopatterns of human salivary glycoproteins and their significant roles against influenza A virus (IVA). Here, we investigate the glycopatterns of human salivary glycoproteins with 180 healthy saliva samples divided into six age/sex groups using lectin microarrays and fabricate saliva microarrays to validate the terminal carbohydrate moieties of glycoproteins in individual saliva samples. Furthermore, we assess the inhibiting and neutralizing activity of saliva against two strains of influenza A (H9N2) virus. We find that seven lectins (e.g., MAL-II and SNA) show significant age differences in both females and males, and seven lectins (e.g., WFA and STL) show significant sex differences in children, adults and elderly people. Interestingly, we observe that elderly individuals have strongest resistance to IVA partly by presenting more terminal α2-3/6-linked sialic acid residues in their saliva, which bind with the influenza viral hemagglutinations. We conclude that age- and sex-associated differences in the glycopatterns of human salivary glycoproteins may provide pivotal information to help understand some age related diseases and physiological phenomena.

The current study evaluated the glycoproteomic profile of tissues from colon cancer patients. The lectin microarray was first performed to compare the glycoprotein profiles between colon cancer and matched normal tissues. Level of N-acetylglucosamine (GlcNAc) that Solanum tuberosum lectin (STL) bound was found to be elevated in colon cancer, which was verified through lectin histochemistry. The subsequent glycoproteomic analysis based on STL enrichment of glycoproteins followed by label-free quantitative nano liquid chromatography-mass spectrometry/mass spectrometry (nanoLC-MS/MS) analysis identified 72 proteins in high confidence. Among these proteins, 17 were exclusively detected in cancer tissues, and 14 were significantly upregulated in tumor tissues. Annexin A1 and HSP90β were chosen for further investigation by immunoprecipitation coupled with lectin blots, western blots and tissue microarrays. Both Annexin A1 and HSP90β were GlcNAcylated, and their protein expressions were elevated in colon cancer, compared to normal tissues. Moreover, specific changes of GlcNAc abundances in Annexin A1 and HSP90β suggested that tumor-specific glycan patterns could serve as candidate biomarkers of colon cancer for distinguishing cancer patients from healthy individuals.

Protein glycosylation plays an important role in the pathogenesis and progression of various liver diseases. However, little is known about the precise alterations in protein glycosylation or the potential correlation between glycan-related genes expression and glycan profiles in liver fibrosis. The aim of the study was to investigate potential associations between glycan-related genes expression and glycan profiles to evaluate liver fibrosis in a mouse model. Analyses of glycan-related genes expression and glycan profiles were performed using oligonucleotide microarrays and lectin microarrays, respectively. Real-time PCR and Western blot were used to confirm any altered glycan-related genes expression levels and protein levels. Moreover, altered glycan patterns on the surface of hepatocytes were verified by lectin histochemistry. These results revealed that the mRNA levels of 10 glycan-related genes were significantly altered in fibrotic liver. Furthermore, we observed an increase in multivalent sialic acid, poly-LacNAc, sialyl-T-antigen, Fucoseα-1,3/6GlcNAc, and GalNAcα1-3Gal in fibrotic liver specimens, whereas GlcNAc oligomers was decreased in fibrotic liver. Our findings indicated that the synthetic pathway of "Tn antigen → T antigen (core-1) → sialyl-T antigen" was activated for O-glycan during the process of liver fibrosis.

Although aberrant glycosylation of human glycoproteins is related to liver fibrosis that results from chronic damage to the liver in conjunction with the activation of hepatic stellate cells (HSCs), little is known about the precision alteration of protein glycosylation referred to the activation of HSCs by transforming growth factor-β1 (TGF-β1). The human HSCs, LX-2 were activated by TGF-β1. The lectin microarrays were used to probe the alteration of protein glycosylation in the activated HSCs compared with the quiescent HSCs. Lectin histochemistry was used to further validate the lectin binding profiles and assess the distribution of glycosidic residues in cells. As a result, 14 lectins (e. g. AAL, PHA-E, ECA and ConA) showed increased signal while 7 lectins (e. g. UEA-I and GNA) showed decreased signal in the activated LX-2 compared with the quiescent LX-2. Meanwhile, AAL, PHA-E and ECA staining showed moderate binding to the cytoplasma membrane in the quiescent LX-2, and the binding intensified in the same regions of the activated LX-2. In conclusion, the precision alteration of protein glycosylation related to the activation of the HSCs may provide useful information to find new molecular mechanism of HSC activation and antifibrotic therapeutic strategies.