Single-nucleus RNA sequencing reveals excitatory and inhibitory neuronal subtype imbalance and its potential regulatory mechanisms in GM1 gangliosidosis.

BACKGROUND: GM1 gangliosidosis is a rare lysosomal storage disorder caused by biallelic mutations in GLB1, leading to progressive neurodegeneration. The cellular and molecular mechanisms, particularly at the neuronal subtype level, remain incompletely understood. OBJECTIVE: The research employed single-nucleus transcription sequencing to explore neuropathological mechanisms associated with GM1 Gangliosidosis systematically. METHODS: High-quality single-nucleus data obtained from GM1 gangliosidosis model mice and wild-type mice underwent comprehensive quality control and dimensionality reduction processing, and extensive clustering and annotation were performed. Subsequently, the neurons were re-annotated, and the differentiation trajectories of different subtypes of neurons were analyzed through temporal sequence modeling, as well as the key communication pathways between them and other cells, as well as the ligand pairs. RESULTS: The main classes of neural cells (neurons, microglia, and astrocytes) could be recognized well. On targeting the neurons alone through focused approach, another round of secondary clustering followed by the labeling of subpopulations showed there are two subgroups within the populatio, excitatory and inhibitory neurons. The results of functional enrichment analysis indicate that the relatively enhanced functions in the GM1 group mainly involve processes such as lytic vacuole organization, ceramide and sphingolipid metabolism, and glycosphingolipid breakdown. The GO analysis of inhibitory neurons shows that processes such as cytoplasmic translation, oxidative phosphorylation, and ATP synthesis are relatively enhanced in the Wildtype group. Pseudo-time analysis further revealed the developmental trajectories of neuronal subpopulations on the pseudo-time axis and the dynamic changes in gene expression. The analysis of intercellular communication revealed that ExNs mainly communicate with OPCs through the Nrg3-Erbb4 pair, while Neutrophils mainly interact with InNs via the Nrg1-Erbb4 pair. CONCLUSION: This study, through a comprehensive analysis of single-nucleus sequencing data of GM1 gangliosidosis, has revealed the key cell subpopulations and their related functions in these diseases, providing a theoretical basis for the mechanism of disease occurrence and possible treatment strategies.