N-acetyl-L-aspartate metabolism (NAA metabolism)

N-acetyl-L-aspartate (NAA) metabolism is a specialized biochemical pathway primarily localized in the vertebrate central nervous system. It involves the synthesis of NAA from acetyl-CoA and L-aspartate by the neuronal enzyme aspartate N-acetyltransferase (NAT8L) and its subsequent hydrolysis into acetate and aspartate by the oligodendrocytic enzyme aspartoacylase (ASPA) (Moffett et al., 2007). NAA is one of the most abundant metabolites in the human brain, where it serves as a critical source of acetate for myelin lipid synthesis, acts as an organic osmolyte, and functions as a precursor for the neurotransmitter N-acetylaspartylglutamate (NAAG) (Baslow, 2003). Dysregulation of this pathway is most notably associated with Canavan disease, a fatal autosomal recessive leukodystrophy caused by mutations in the ASPA gene, leading to toxic accumulation of NAA and spongy degeneration of the brain (Surendran et al., 2003). Furthermore, NAA levels are widely utilized as a non-invasive surrogate biomarker for neuronal health and density in various neurodegenerative disorders, including Alzheimer's disease and multiple sclerosis, using proton magnetic resonance spectroscopy (1H-MRS) (Barker, 2001). Recent evidence also suggests that NAT8L-mediated NAA production may support the metabolic requirements of certain malignant tumors, positioning components of this pathway as potential targets for oncology therapeutics (Bogner-Straub et al., 2017).

Other names

NAA metabolismN-acetylaspartate metabolismN-acetylaspartic acid metabolism

Gene therapy (rAAV-ASPA) provides a functional copy of the ASPA gene to restore enzyme activity and reduce NAA levels (Leone et al., 2012). Triacetin serves as an acetate prodrug to compensate for the lack of acetate production from NAA hydrolysis (Madhavarao et al., 2009). Lithium reduces NAA levels through mechanisms that may involve inhibition of NAT8L or modulation of NAA transport (Baslow et al., 2007).