<i>In vitro</i> modeling of experimental succinic semialdehyde dehydrogenase deficiency (SSADHD) using brain-derived neural stem cells

<div><p>We explored the utility of neural stem cells (NSCs) as an <i>in vitro</i> model for evaluating preclinical therapeutics in succinic semialdehyde dehydrogenase-deficient (SSADHD) mice. NSCs were obtained from <i>aldh5a1</i>^<i>+/+</i> and <i>aldh5a1</i>^<i>-/-</i> mice (aldh5a1 = aldehyde dehydrogenase 5a1 = SSADH). Multiple parameters were evaluated including: (1) production of GHB (γ-hydroxybutyrate), the biochemical hallmark of SSADHD; (2) rescue from cell death with the dual mTOR (mechanistic target of rapamycin) inhibitor, XL-765, an agent previously shown to rescue <i>aldh5a1</i>^<i>-/-</i> mice from premature lethality; (3) mitochondrial number, total reactive oxygen species, and mitochondrial superoxide production, all previously documented as abnormal in <i>aldh5a1</i>^<i>-/-</i> mice; (4) total ATP levels and ATP consumption; and (5) selected gene expression profiles associated with epilepsy, a prominent feature in both experimental and human SSADHD. Patterns of dysfunction were observed in all of these parameters and mirrored earlier findings in <i>aldh5a1</i>^<i>-/-</i> mice. Patterns of dysregulated gene expression between hypothalamus and NSCs centered on ion channels, GABAergic receptors, and inflammation, suggesting novel pathomechanisms as well as a developmental ontogeny for gene expression potentially associated with the murine epileptic phenotype. The NSC model of SSADHD will be valuable in providing a first-tier screen for centrally-acting therapeutics and prioritizing therapeutic concepts of preclinical animal studies applicable to SSADHD.</p>