Production and characterization of monoclonal antibodies specific to lactotriaosylceramide

MiR-30a-5p inhibits proliferation and metastasis of hydatidiform mole by regulating B3GNT5 through ERK/AKT pathways

Hydatidiform moles are gestational trophoblastic disease. They are abnormal proliferations of trophoblast cells that have the potential to become cancerous. miR-miR30a-5p is a tumour suppressor that participates in the development of numerous diseases. However, the role of miR-30a in hydatidiform moles and the mechanisms underlying its effects are presently unclear. This study explored the levels of miR-30a and B3GNT5 expression in human hydatidiform mole tissue. The results showed that miR-30a and B3GNT5 were differentially expressed in normal placenta and hydatidiform mole, and miR-30a decreased cell proliferation, invasion and migration in trophoblast cell lines. Upon further examination, it was confirmed that miR-30a directly targeted the 3'untranslated region of B3GNT5 using a dual-luciferase assay. The results of the present study also revealed that miR-30a reduced the proliferation, invasion and migration ability in JAR and BeWo cells by regulating B3GNT5, which may inactivate the ERK and AKT signalling pathways. This study demonstrated that miR-30a was a novel target B3GNT5 that serves an important role in the development of hydatidiform moles, suggesting that miR-30a may serve as a novel potential biomarker or useful diagnostic and therapeutic tool for hydatidiform moles in clinical settings.

Altered (neo-) lacto series glycolipid biosynthesis impairs α2-6 sialylation on N-glycoproteins in ovarian cancer cells

The (neo-) lacto series glycosphingolipids (nsGSLs) comprise of glycan epitopes that are present as blood group antigens, act as primary receptors for human pathogens and are also increasingly associated with malignant diseases. Beta-1, 3-N-acetyl-glucosaminyl-transferase 5 (B3GNT5) is suggested as the key glycosyltransferase for the biosynthesis of nsGSLs. In this study, we investigated the impact of CRISPR-Cas9 -mediated gene disruption of B3GNT5 (∆B3GNT5) on the expression of glycosphingolipids and N-glycoproteins by utilizing immunostaining and glycomics-based PGC-UHPLC-ESI-QTOF-MS/MS profiling. ∆B3GNT5 cells lost nsGSL expression coinciding with reduction of α2-6 sialylation on N-glycoproteins. In contrast, disruption of B4GALNT1, a glycosyltransferase for ganglio series GSLs did not affect α2-6 sialylation on N-glycoproteins. We further profiled all known α2-6 sialyltransferase-encoding genes and showed that the loss of α2-6 sialylation is due to silencing of ST6GAL1 expression in ∆B3GNT5 cells. These results demonstrate that nsGSLs are part of a complex network affecting N-glycosylation in ovarian cancer cells.

Inhibition of Rab prenylation by statins induces cellular glycosphingolipid remodeling

Statins, which specifically inhibit HMG Co-A reductase, the rate-limiting step of cholesterol biosynthesis, are widely prescribed to reduce serum cholesterol and cardiac risk, but many other effects are seen. We now show an effect of these drugs to induce profound changes in the step-wise synthesis of glycosphingolipids (GSLs) in the Golgi. Glucosylceramide (GlcCer) was increased several-fold in all cell lines tested, demonstrating a widespread effect. Additionally, de novo or elevated lactotriaosylceramide (Lc3Cer; GlcNAcβ1-3Galβ1-4GlcCer) synthesis was observed in 70%. Western blot showed that GlcCer synthase (GCS) was elevated by statins, and GCS and Lc3Cer synthase (Lc3S) activities were increased; however, transcript was elevated for Lc3S only. Supplementation with the isoprenoid precursor, geranylgeranyl pyrophosphate (GGPP), a downstream product of HMG Co-A reductase, reversed statin-induced glycosyltransferase and GSL elevation. The Rab geranylgeranyl transferase inhibitor 3-PEHPC, but not specific inhibitors of farnesyl transferase, or geranylgeranyl transferase I, was sufficient to replicate statin-induced GlcCer and Lc3Cer synthesis, supporting a Rab prenylation-dependent mechanism. While total cholesterol was unaffected, the trans-Golgi network (TGN) cholesterol pool was dissipated and medial Golgi GCS partially relocated by statins. GSL-dependent vesicular retrograde transport of Verotoxin and cholera toxin to the Golgi/endoplasmic reticulum were blocked after statin or 3-PEHPC treatment, suggesting aberrant, prenylation-dependent vesicular traffic as a basis of glycosyltransferase increase and GSL remodeling. These in vitro studies indicate a previously unreported link between Rab prenylation and regulation of GCS activity and GlcCer metabolism.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.

Co-transplantation of human fetal thymus, bone and CD34(+) cells into young adult immunodeficient NOD/SCID IL2Rγ(null) mice optimizes humanized mice that mount adaptive antibody responses

Both the thymus (T) and bone (B) are necessary hematopoietic niches in adult humans. We previously showed that co-transplantation of human fetal T and B tissues into neonatal immunodeficient NOD/SCID IL2Rγ(null) (NSG, N) mice facilitated hematopoiesis. However, transplantation into neonatal mice resulted in high frequency of early death, making it unrealistic for repetitive experiments. In this study, young adult N mice were pre-engrafted with T and B, T alone, B alone or no tissues. The animals were irradiated and injected with autologous fetal liver (FL)-derived CD34(+) cells (34). The resultant mice were TB34N, T34N, B34N and 34N, respectively, and challenged with T cell dependent antigens (Ags). The humanized TB34N mice showed best performance of these mouse models in many aspects resembling the adult human Ag-experienced spleen. The TB34N mice exhibited better hematopoietic reconstitution; balanced development of T- and B-cell, and common progenitor cells; follicular lymphoid structures with a functional germinal center (GC) enriched with follicular dendritic cells (FDCs) and plasma cells (PCs); secretion of hIgG in the sera in response to Ags at comparable levels to those of human; derivations of hIgG mAb-secreting hybridoma clones. Collectively, the humanized TB34N mice could develop an adaptive immunity that was capable of producing Ag-specific hIgG at a significant level via class switching. This unprecedented TB34N platform in humanized mice would be useful in dissecting human immunity, for generating human Abs and clinical applications.

High expression of lactotriaosylceramide, a differentiation-associated glycosphingolipid, in the bone marrow of acute myeloid leukemia patients

Glycosphingolipids (GSLs) are information-bearing biomolecules that play critical roles in embryonic development, signal transduction and carcinogenesis. Previous studies indicate that certain GSLs are associated with differentiation in acute myeloid leukemia (AML) cells. In this study, we collected bone marrow samples from healthy donors and AML patients and analyzed the GSL expression profiles comprehensively using electrospray ionization linear ion-trap mass spectrometry. The results showed that AML patients had higher expression of the GSL lactotriaosylceramide (Lc3), GM3 and neolactotetraosylceramide (nLc4) in their bone marrow than did the healthy donors (P < 0.05), especially the M1 subtype of AML. To further explore the molecular mechanisms of Lc3, we examined the expression of the Lc3 synthase β1,3-N-acetylglucosaminyltransferase5 (β3Gn-T5) and found that the bone marrow samples of AML patients had 16-fold higher expression of β3Gn-T5 than those of healthy donors (P < 0.05). Our results suggest that AML-associated GSLs Lc3, GM3 and nLc4 are possibly involved in initiation and differentiation of AML.