Analysis of differential expression of glycosyltransferases in healing corneas by glycogene microarrays.
ABSTRACT It is generally accepted that the glycans on the cell surface and extracellular matrix proteins play a pivotal role in the events that mediate re-epithelialization of wounds. Yet, the global alteration in the structure and composition of glycans, specifically occurring during corneal wound closure remains unknown. In this study, GLYCOv2 glycogene microarray technology was used for the first time to identify the differentially expressed glycosylation-related genes in healing mouse corneas. Of approximately 2000 glycogenes on the array, the expression of 11 glycosytransferase and glycosidase enzymes was upregulated and that of 19 was downregulated more than 1.5-fold in healing corneas compared with the normal, uninjured corneas. Among them, notably, glycosyltransferases, beta3GalT5, T-synthase, and GnTIVb, were all found to be induced in the corneas in response to injury, whereas, GnTIII and many sialyltransferases were downregulated. Interestingly, it appears that the glycan structures on glycoproteins and glycolipids, expressed in healing corneas as a result of differential regulation of these glycosyltransferases, may serve as specific counter-receptors for galectin-3, a carbohydrate-binding protein, known to play a key role in re-epithelialization of corneal wounds. Additionally, many glycogenes including a proteoglycan, glypican-3, cell adhesion proteins dectin-1 and -2, and mincle, and mucin 1 were identified for the first time to be differentially regulated during corneal wound healing. Results of glycogene microarray data were confirmed by qRT-PCR and lectin blot analyses. The differentially expressed glycogenes identified in the present study have not previously been investigated in the context of wound healing and represent novel factors for investigating the role of carbohydrate-mediated recognition in corneal wound healing.
SourceAvailable from: Joana Tavares de Oliveira[Show abstract] [Hide abstract]
ABSTRACT: Galectins are a family of proteins that contain a canonical carbohydrate-recognition domain (CRD) with affinity for beta-galactosides. Within this family, an unique member, the chimeric, galectin-3, may be found in the cytoplasm and nucleus, and on the cell surface, besides being released into the extracellular space. Galectin-3 interactions with certain glycans and extracellular matrix (ECM) proteins have been described to promote and/or antagonize tumor cell apoptosis, to induce endothelial cell proliferation and angiogenesis, and to promote tumor cell adhesion and invasion, thus both potentially facilitating and hindering metastasis. Moreover, although galectin-3 is expressed in several types of malignancies and its expression has been correlated with transformation and metastasis-related events, its downregulation has also been associated with malignancy and tumor progression. These apparently conflicting data demonstrate that the role of galectin-3 in metastasis remains to be fully understood. Of course in nature, different cancer progression phenomena are simultaneously occurring in the many instances, where the patient has primary tumor and blood-borne and distant metastatic cells. This makes it all the more interesting to overview the role of galectins in cancer metastasis, especially galectin-3, since these and their related molecules are more than probable disease marker candidates and/or therapeutic targets.01/2015; DOI:10.4137/GBI.S13916
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ABSTRACT: The complexity of protein glycosylation makes it difficult to characterize glycosylation patterns on a proteomic scale. In this study, we developed an integrated strategy for comparatively analyzing N-glycosylation/glycoproteins quantitatively from complex biological samples in a high-throughput manner. This strategy entailed separating and enriching glycopeptides/glycoproteins using lectin affinity chromatography, and then tandem labeling them with 18O/16O to generate a mass shift of 6 Da between the paired glycopeptides, and finally analyzing them with liquid chromatography-mass spectrometry (LC-MS) and the automatic quantitative method we developed based on Mascot Distiller. The accuracy and repeatability of this strategy were first verified using standard glycoproteins; linearity was maintained within a range of 1:10-10:1. The peptide concentration ratios obtained by the self-build quantitative method were similar to both the manually calculated and theoretical values, with a standard deviation (SD) of 0.023-0.186 for glycopeptides. The feasibility of the strategy was further confirmed with serum from hepatocellular carcinoma (HCC) patients and healthy individuals; the expression of 44 glycopeptides and 30 glycoproteins were significantly different between HCC patient and control serum. This strategy is accurate, repeatable, and efficient, and may be a useful tool for identification of disease-related N-glycosylation/glycoprotein changes.Proteome Science 01/2014; 12(1):4. DOI:10.1186/1477-5956-12-4 · 1.88 Impact Factor
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ABSTRACT: Glycogenes regulate a wide array of biological processes in the development of organisms as well as different diseases such as cancer, primary open-angle glaucoma, and renal dysfunction. The objective of this study was to explore the role of differentially expressed glycogenes (DEGGs) in three major tissues such as brain, muscle, and liver using mouse RNA-seq data, and we identified 579, 501, and 442 DEGGs for brain versus liver (BvL579), brain versus muscle (BvM501), and liver versus muscle (LvM442) groups. DAVID functional analysis suggested inflammatory response, glycosaminoglycan metabolic process, and protein maturation as the enriched biological processes in BvL579, BvM501, and LvM442, respectively. These DEGGs were then used to construct three interaction networks by using GeneMANIA, from which we detected potential hub genes such as PEMT and HPXN (BvL579), IGF2 and NID2 (BvM501), and STAT6 and FLT1 (LvM442), having the highest degree. Additionally, our community analysis results suggest that the significance of immune system related processes in liver, glycosphingolipid metabolic processes in the development of brain, and the processes such as cell proliferation, adhesion, and growth are important for muscle development. Further studies are required to confirm the role of predicted hub genes as well as the significance of biological processes.International Journal of Plant Genomics 07/2014; Volume 2014 (2014)(Article ID 837365). DOI:10.1155/2014/837365