Background: In glioblastoma (GBM), the effects of altered glycocalyx are largely unexplored. The terminal moiety of cell coating glycans, sialic acid, is of paramount importance for cell-cell contacts. However, sialic acid turnover in gliomas and its impact on tumor networks remain unknown.
Methods: We streamlined an experimental setup using organotypic human brain slice cultures as a framework for exploring brain glycobiology, including metabolic labeling of sialic acid moieties and quantification of glycocalyx changes. By live, 2-photon and high-resolution microscopy we have examined morphological and functional effects of altered sialic acid metabolism in GBM. By calcium imaging we investigated the effects of the altered glycocalyx on a functional level of GBM networks.
Results: The visualization and quantitative analysis of newly synthesized sialic acids revealed a high rate of de novo sialylation in GBM cells. Sialyltrasferases and sialidases were highly expressed in GBM, indicating that significant turnover of sialic acids is involved in GBM pathology. Inhibition of either sialic acid biosynthesis or desialylation affected the pattern of tumor growth and lead to the alterations in the connectivity of glioblastoma cells network.
Conclusions: Our results indicate that sialic acid is essential for the establishment of GBM tumor and its cellular network. They highlight the importance of sialic acid for glioblastoma pathology and suggest that dynamics of sialylation have the potential to be targeted therapeutically.
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http://dx.doi.org/10.1093/neuonc/noad101 | DOI Listing |
Chemistry
January 2025
Griffith University - Gold Coast Campus, Institute for Biomedicine and Glycomics, Parklands Drive, 4222, Southport, AUSTRALIA.
3-Fluoroneuraminosyl fluorides are invaluable probes for studying the catalytic mechanism of sialidases (neuraminidases), and as sialidase inhibitors. Significantly, when a C-3 equatorial fluorine is installed on a C-4 functionalised N-acylneuraminic acid (Neu)-based template, the compounds are potent and selective inhibitors of both influenza and parainfluenza sialidases, and of virus replication. Typically, the reported syntheses of 3-fluoroneuraminosyl fluorides involve either an enzymatic or a chemical synthesis that have uncontrolled stereoselectivity in the introduction of fluorine at C-3 of Neu and consequently yield a mixture of C-3 ax and C-3 eq fluoro derivatives.
View Article and Find Full Text PDFEmerg Microbes Infect
January 2025
Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Liaoning Panjin Wetland Ecosystem National Observation and Research Station, Shenyang Agricultural University, Shenyang, People's Republic of China.
The H9N2 subtype of avian influenza virus (AIV) is widely distributed among poultry and wild birds and is also a threat to humans. During AIV active surveillance in Liaoning province from 2015 to 2016, we identified ten H9N2 strains exhibiting different lethality to chick embryos. Two representative strains, A/chicken/China/LN07/2016 (CKLN/07) and A/chicken/China/LN17/2016 (CKLN/17), with similar genomic background but different chick embryo lethality, were chosen to evaluate the molecular basis for this difference.
View Article and Find Full Text PDFFront Parasitol
May 2024
Disease Control and Elimination (DCE), Medical Research Council The Gambia Unit at the London School of Hygiene and Tropical Medicine (LSHTM), Fajara, Gambia.
Further understanding of the molecular mediators of alternative RBC invasion phenotypes in endemic malaria parasites will support malaria blood-stage vaccine or drug development. This study investigated the prevalence of sialic acid (SA)-dependent and SA-independent RBC invasion pathways in endemic parasites from Cameroon and compared the schizont stage transcriptomes in these two groups to uncover the wider repertoire of transcriptional variation associated with the use of alternative RBC invasion pathway phenotypes. A two-color flow cytometry-based invasion-inhibition assay against RBCs treated with neuraminidase, trypsin, and chymotrypsin and deep RNA sequencing of schizont stages harvested in the first replication cycle in culture were employed in this investigation.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Computational Biology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
The clownfish - sea anemone system is a great example of symbiotic mutualism where host «toxicity» does not impact its symbiont partner, although the underlying protection mechanism remains unclear. The regulation of nematocyst discharge in cnidarians involves N-acetylated sugars like sialic acid, that bind chemoreceptors on the tentacles of sea anemones, leading to the release of stings. It has been suggested that clownfish could be deprived of sialic acid on their skin surface, sparing them from being stung and facilitating mutualism with sea anemones.
View Article and Find Full Text PDFSci Transl Med
January 2025
College of Pharmaceutical Sciences, State Key Laboratory of Advanced Drug Delivery and Release Systems, Zhejiang University, Hangzhou 310058, China.
Macrophages play a central role in antitumor immunity, making them an attractive target for gene therapy strategies. However, macrophages are difficult to transfect because of nucleic acid sensors that can trigger the degradation of foreign plasmid DNA. Here, we developed a macrophage-specific editing (MAGE) system by which compact plasmid DNA encoding a CasRx editor can be delivered to macrophages by a poly(β-amino ester) (PBAE) carrier to bypass the DNA sensor and enable RNA editing in vitro and in vivo.
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