Biology subjects

van Aalten, D.

Publications and source records attributed to van Aalten, D..

3 recordsLinked to original sources

bioRxiv2025

Genetic rescue of pathogenic O-GlcNAc dyshomeostasis associated with microcephaly and motor deficits

Missense variants in O-GlcNAc transferase (OGT) result in OGT congenital disorder of glycosylation (OGT-CDG), an intellectual disability syndrome associated with O-GlcNAc dyshomeostasis and a range of neurodevelopmental defects. Inhibition of O-GlcNAcase (OGA), the enzyme responsible for removing protein O-GlcNAcylation, has been explored as a target for modulating brain O-GlcNAc homeostasis in neurodegenerative diseases and may also be a target for OGT-CDG. Here, we describe an OGT-CDG mouse line that exhibits microcephaly, motor deficits, and brain O-GlcNAc dyshomeostasis, closely mirroring patient symptoms. We genetically explored OGA as a target for OGT-CDG by crossing these mice with a line carrying catalytically inactive OGA. Encouragingly, this partially restored O-GlcNAc homeostasis in brain and blood, although it did not result in significant phenotypic rescue. These findings suggest that OGA inhibition can modulate enzymatic imbalance in OGT-CDG mice, and that blood can be used to monitor the effects of interventions targeting O-GlcNAc dyshomeostasis.

neuroscience↗

bioRxiv2025

A triple fluorescence approach to measure O-GlcNAc dyshomeostasis in stem cells

O-GlcNAcylation is an essential post-translational modification, the complete loss of which results in lethality. Despite modifying thousands of nucleocytoplasmic proteins, O-GlcNAc is controlled by just two enzymes: O-GlcNAc transferase (OGT), which adds the modification, and O-GlcNAcase (OGA), which removes it. Disruptions in O-GlcNAc homeostasis, such as an imbalanced OGT/OGA ratio or aberrant O-GlcNAc levels, are implicated in a wide range of human diseases, including Alzheimers disease, cancer, intellectual disability, and diabetes. As such, O-GlcNAc and its regulatory enzymes represent valuable therapeutic targets. However, current tools do not permit informative, large-scale drug or genetic screening, hindering the development of O-GlcNAc-targeted therapies. Here, we present a triple fluorescence stem cell sorting approach in which both endogenous OGT and OGA are tagged with spectrally distinct fluorescent proteins and O-GlcNAc levels can be quantified. We demonstrate that this system faithfully reports disruptions in O-GlcNAc homeostasis. Furthermore, we show that the O-GlcNAc feedback regulation is not solely dependent on O-GlcNAc levels, indicating a role for non-catalytic functions of OGT and OGA. Overall, we provide a high-throughput screening platform that enables reliable and quantitative measurement of O-GlcNAc homeostasis, paving the way for identifying compounds and pathways that target protein O-GlcNAcylation.

molecular biology↗

bioRxiv2023

Rescuable sleep and synaptogenesis phenotypes in a Drosophila model of O-GlcNAc transferase intellectual disability.

O-GlcNAcylation is an essential intracellular protein modification mediated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Recently, missense mutations in OGT have been linked to intellectual disability, indicating that this modification is important for the development and functioning of the nervous system. However, the processes that are most sensitive to perturbations in O-GlcNAcylation remain to be identified. Here, we uncover quantifiable phenotypes in the fruit fly Drosophila melanogaster carrying a patient-derived OGT mutation in the catalytic domain. Hypo-O-GlcNAcylation leads to defects in synaptogenesis and reduced sleep stability. Both these phenotypes can be partially rescued by genetically or chemically targeting OGA, suggesting that a balance of OGT/OGA activity is required for normal neuronal development and function.

genetics↗