The role of beta-1,4-galactosyltransferase-I in the skin wound-healing process

B4GALT1 gene knockdown inhibits the hedgehog pathway and reverses multidrug resistance in the human leukemia K562/adriamycin-resistant cell line

B4GALT1 gene encodes type II membrane-bound glycoprotein, named β-1, 4-galactosyltransferase 1 (β1, 4-Gal-T1), which can transfer galactose to acceptor sugars. B4GALT1 gene plays important roles in physiological process and disease development. In this study, we investigate the possible role and mechanism of B4GALT1 gene in multidrug resistance of human leukemia cell line. Significantly, higher expression of B4GALT1 was observed in adriamycin-resistant (ADR) K562 cell line (K562/ADR) than that in K562 cell line by real-time polymerase chain reaction and Western blotting. The activity of β1, 4-Gal-T1 enzyme, and Galβ-1,4GlcNAc structures on cell membrane glycoproteins was found at higher levels in K562/ADR cells than those in K562 cells. Further analysis of the B4GALT1 deregulation after using RNA interference approach showed that the silencing of B4GALT1 in K562/ADR cells resulted in increased sensitivity to chemotherapeutic drugs both in vitro and in vivo. The activity of the hedgehog signaling pathway affected the chemosensitivity of K562/ADR cells and was downregulated in K562/ADR cells with suppression of B4GALT1 gene. We hypothesize that B4GALT1 is responsible for the overcoming multidrug resistance in human leukemia therapy via regulating the activity of the hedgehog signaling pathway.

β-1,4-Galactosyltransferase I involved in Schwann cells proliferation and apoptosis induced by tumor necrosis factor-alpha via the activation of MAP kinases signal pathways

β-1,4-galactosyltransferase-I (β-1,4-GalT-I) plays a critical role in the initiation and maintenance of peripheral nervous system inflammatory reaction. However, the exact function of β-1,4-GalT-I in the regulation of SCs proliferation and apoptosis remains unclear. In this study, we found that low concentration of tumor necrosis factor-alpha (TNF-α) induced SCs proliferation, while high concentration of TNF-α induced SCs apoptosis. Meanwhile, the expressions of β-1,4-GalT-I, TNFR1, and TNFR2 were changed following. When β-1,4-GalT I overexpression, low concentration of TNF-α-induced SCs proliferation was partially repressed. Concurrently, the activity of ERK1/2 was decreased. While knocking down β-1,4-GalT I expression, high concentration of TNF-α-induced SCs apoptosis was partially rescued. Consistent with this, the activity of P38 and JNK were decreased. We also found anti-TNFR2 antibody suppressed low concentration of TNF-α-induced SCs proliferation, while anti-TNFR1 antibody inhibited high concentration of TNF-α-induced SCs apoptosis. Thus, present data show that β-1,4-GalT I may play an important role in SCs proliferation and apoptosis induced by TNF-α via different signal pathways and TNFR.

Analysis of differential expression of glycosyltransferases in healing corneas by glycogene microarrays

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.