SLC44A1 deficiency impedes myelin development in the central nervous system

Metabolomic profiling reveals disrupted choline metabolism in SLC44A1-deficient oligodendrocytes

We hypothesized that the deficiency of SLC44A1, a key choline transporter in oligodendrocytes, disrupts intracellular choline metabolism, thereby impairing the synthesis of critical phospholipid precursors essential for myelin biogenesis.

To investigate this, we performed quantitative metabolomic profiling on primary rat oligodendrocytes following lentivirus-mediated knockdown of Slc44a1. Cells were cultured under differentiation conditions for 3 days post-infection. Metabolites were extracted using a pre-cooled acetonitrile-methanol-water solvent system, followed by analysis with liquid chromatography-tandem mass spectrometry (LC-MS/MS) on a UPLC system coupled to an AB Sciex QTrap 6500 plus mass spectrometer. The platform employed a Z-HILIC column for separation and multiple reaction monitoring (MRM) for targeted quantification of metabolites.

Our data identified 86 significantly altered metabolites in Slc44a1-knockdown oligodendrocytes compared to controls, with 72 metabolites being downregulated. Pathway enrichment analysis of these downregulated metabolites highlighted a significant disruption in the choline metabolism pathway. Most notably, citicoline (also known as CDP-choline)—the direct metabolic intermediate and rate-limiting precursor for phosphatidylcholine (PC) synthesis—exhibited the most pronounced reduction. This finding aligns with our concurrent observation of decreased PCYT1A expression, the enzyme that catalyzes the conversion of phosphocholine to citicoline in the Kennedy pathway.

These metabolomic results demonstrate that SLC44A1 deficiency severely compromises the choline metabolic flux in oligodendrocytes, specifically at the critical step of citicoline production. This disruption provides a mechanistic explanation for the observed deficits in phosphatidylcholine levels and subsequent myelin membrane expansion failures. The data underscore the essential role of SLC44A1 in sustaining the metabolic backbone required for myelination.

This metabolomics dataset offers a detailed view of the metabolic perturbations underlying oligodendrocyte dysfunction in SLC44A1 deficiency. It serves as a valuable resource for understanding the metabolic demands of myelination and for identifying potential intervention points for disorders of myelin development.