Tracking of in vivo O-GlcNAcylation in an Alzheimer's Disease and Aging C. elegans Model

Abstract

We investigated O-linked {beta}-N-acetylglucosamine (O-GlcNAc), a post-translational modification (PTM), in an in vivo Caenorhabditis elegans model of Alzheimer\'s Disease (AD) and aging. Employing a chemoenzymatic labeling strategy combined with an automated image processing, we analyzed both post-hatching and adult stages of wild-type (WT, N2) and transgenic strain expressing human tau V337M under the aex-3 promoter (aex-3p::tau(V337M)). Nematodes were incubated with an azido-modified N-acetylglucosamine analog, followed by copper-catalyzed azide-alkyne cycloaddition (CuAAC) with an alkyne-conjugated dye. Labeled O-GlcNAc proteins were visualized via fluorescence microscopy and quantified using a region-of-interest (ROI)-based image analysis pipeline. Morphometric characterization revealed an age-dependent increase in O-GlcNAcylation in WT worms, whereas the AD model showed a progressive decline. O-GlcNAc-labeled ROIs exhibited a shift from anterograde to predominantly retrograde transport in middle-aged worms, suggesting that aging and neurodegeneration alter O-GlcNAc trafficking dynamics, potentially reflecting impaired synaptic support or enhanced clearance in C. elegans.