Genetic Rescue of Pathogenic O-GlcNAc Dyshomeostasis Associated with Microcephaly and Motor Deficits

Area of Science:

• Biochemistry
• Neuroscience
• Genetics

Background:

• O-GlcNAc transferase (OGT) mutations cause OGT congenital disorder of glycosylation (OGT-CDG), a neurodevelopmental disorder.
• O-GlcNAc dyshomeostasis is a key feature of OGT-CDG, impacting brain development and function.
• Inhibition of O-GlcNAcase (OGA) is a potential therapeutic strategy for OGT-CDG.

Purpose of the Study:

• To develop and characterize a mouse model for OGT-CDG.
• To investigate OGA as a therapeutic target for OGT-CDG.
• To assess the utility of blood as a biomarker for OGT-CDG interventions.

Main Methods:

• Generated an OGT-CDG mouse line exhibiting microcephaly, motor deficits, and O-GlcNAc dyshomeostasis.
• Crossed OGT-CDG mice with mice carrying catalytically inactive OGA to genetically explore OGA inhibition.
• Measured Ogt/Oga mRNA ratio in brain and blood to assess O-GlcNAc homeostasis.

Main Results:

• The OGT-CDG mouse model recapitulated key features of human OGT-CDG, including neurodevelopmental defects.
• Genetic inhibition of OGA partially restored O-GlcNAc homeostasis in the brain and blood of OGT-CDG mice.
• The Ogt/Oga mRNA ratio served as a measurable indicator of O-GlcNAc homeostasis modulation.

Conclusions:

• OGA inhibition is a promising strategy for modulating enzymatic imbalance in OGT-CDG.
• The developed mouse model provides a valuable platform for studying OGT-CDG pathogenesis and testing therapies.
• Blood O-GlcNAc homeostasis can be monitored to evaluate the efficacy of OGT-CDG interventions.