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Miazek, A.

Publications and source records attributed to Miazek, A..

2 recordsLinked to original sources

Homecage-Like Monitoring Reveals Domain-Specific Rescue of Central SPTAN1 R1098Q Phenotypes by Wild-Type Partner Co-Housing

Neurodegenerative disorders manifest with markedly different phenotypes, with motor- and memory impairments dominating both clinical and preclinical phenotyping efforts. However, neurodegeneration in unlikely to be confined to these two functional domains alone, and its broader behavioral consequences, including social alterations remain underexplored. Here, we present a non-invasive, high-content home-cage phenotyping framework to investigate social and exploratory dysfunction in SPTAN1 R1098Q mice, a model of early infantile epileptic encephalopathy (EIEE5). Our pipeline integrates three open-source AI engines: SLEAP.ai for markerless multi-animal pose estimation, DeepOF for automated classification of autonomous and social behaviors, and SAM2 for segmentation and quantification of nest-building material usage. Long-term monitoring revealed that SPTAN1 R1098Q mutants exhibit impaired spatial habituation in mutant-mutant (MUT - MUT) pairs. Mutants also displayed persistent, unreciprocated trailing (following) of cage mates and a pronounced reduction of nest-building behavior alongside. Notably, co-housing with a wild-type littermate (MUT - WT) attenuated mutant hyperactivity and restored more typical rest pattern, suggesting that social context can partially buffer these behavioral abnormalities. By revealing social and exploratory alterations that expand conventional phenotyping, this computational ethology pipeline advances 3R principles while revealing that intrinsic executive state-switching failures in neurodegenerative models can be functionally buffered by social dynamics.

animal behavior and cognition↗

Missing the sweet spot: one of the two N-glycans on human Gb3/CD77 synthase curtails its activity

N-glycosylation is a ubiquitous posttranslational modification that may influence folding, subcellular localization, secretion, solubility and oligomerization of proteins. In this study, we examined the effects of N-glycans on the activity of human Gb3/CD77 synthase, which catalyzes the synthesis of glycosphingolipids with terminal Gal1[->]4Gal (Gb3 and the P1 antigen) and Gal1[->]4GalNAc disaccharides (the NOR antigen). The human Gb3/CD77 synthase contains two occupied N-glycosylation sites at positions N121 and N203. Intriguingly, we found that while the N-glycan at N203 is essential for activity and correct subcellular localization, the N-glycan at N121 is dispensable and its absence did not reduce, but, surprisingly, even increased the activity of the enzyme. The fully N-glycosylated human Gb3/CD77 synthase and its glycoform missing the N121 glycan correctly localized in the Golgi, whereas a glycoform without the N203 site partially mislocalized in the endoplasmic reticulum. A double mutein missing both N-glycans was inactive and accumulated in the endoplasmic reticulum. Our results suggest that the decreased specific activity of human Gb3/CD77 synthase glycovariants results from their improper subcellular localization and, to a smaller degree, a decrease in enzyme solubility. Taken together, our findings show that the two N-glycans of human Gb3/CD77 synthase have opposing effects on its properties, revealing a dual nature of N-glycosylation and potentially a novel regulatory mechanism controlling the biological activity of proteins.

biochemistry↗