Brain Nat8l Knockdown Suppresses Spongiform Leukodystrophy in an Aspartoacylase-Deficient Canavan Disease Mouse Model

Abstract

Canavan disease, a leukodystrophy caused by loss-of-function ASPA mutations, is characterized by brain dysmyelination, vacuolation, and astrogliosis ("spongiform leukodystrophy"). ASPA encodes aspartoacylase, an oligodendroglial enzyme that cleaves the abundant brain amino acid N-acetyl-L-aspartate (NAA) to L-aspartate and acetate. Aspartoacylase deficiency results in a 50% or greater elevation in brain NAA concentration ([NAA]). Prior studies showed that homozygous constitutive knockout of Nat8l, the gene encoding the neuronal NAA synthesizing enzyme N-acetyltransferase 8-like, prevents aspartoacylase-deficient mice from developing spongiform leukodystrophy. We now report that brain Nat8l knockdown elicited by intracerebroventricular/intracisternal administration of an adeno-associated viral vector carrying a short hairpin Nat8l inhibitory RNA to neonatal aspartoacylase-deficient Aspa mice lowers [NAA] and suppresses development of spongiform leukodystrophy.

Antisense Oligonucleotide Reverses Leukodystrophy in Canavan Disease Mice

“…Though early postnatal AAV‐mediated Aspa gene therapy prevents leukodystrophy in CD mice, attempts to translate Aspa gene therapy to infants and children with symptomatic CD have thus far failed to reverse pre‐existing neurological deficits or to prevent disease progression . Neonatal intracerebroventricular administration of an AAV incorporating a short hairpin Nat8l inhibitory RNA to CD mice, which lowered [NAA B ] toward normal, also prevented development of leukodystrophy . However, a sharp decrease in brain transduction by the AAV vector after the newborn period precluded evaluation of the potential of this therapy to reverse pre‐existing ataxia, cerebellar vacuolation, and alterations in Purkinje cell morphology in the CD mice.…”

“…4 Neonatal intracerebroventricular administration of an AAV incorporating a short hairpin Nat8l inhibitory RNA to CD mice, which lowered [NAA B ] toward normal, also prevented development of leukodystrophy. 15 However, a sharp decrease in brain transduction by the AAV vector after the newborn period precluded evaluation of the potential of this therapy to reverse pre-existing ataxia, cerebellar vacuolation, and alterations in Purkinje cell morphology in the CD mice.…”

Function of Akkermansia muciniphila in Obesity: Interactions With Lipid Metabolism, Immune Response and Gut Systems

“…In cAMP-responsive binding protein H (CREBH) deficiency-induced hyperlipidemia mice, A. muciniphila inoculation could cause clearance of triglyceride and postprandial chylomicrons to avoid acute lipid overload in the circulation. During the clearance progress, the expression of low-density lipoprotein (LDL) receptors was increased, which facilitated the upregulation of intermediatedensity lipoprotein (IDL) via the induction of apolipoprotein B 100 and apolipoprotein E Bannerman et al, 2018). Thus, replenishment with A. muciniphila can ameliorate western diet-induced atherosclerotic lesion aggravation in Apolipoprotein E deficient (Apoe −/− ) mice.…”

Nucleic Acid–Based Therapeutics in Orphan Neurological Disorders: Recent Developments

“…As homozygous or heterozygous constitutive knockouts of Nat8l, an enzyme that synthesizes NAA and reduced disease severity in a CD disease model (AspaNur7/Nur7 mice), an NBT-mediated knockdown of this enzyme was attempted. Bannerman et al ( Bannerman et al, 2018 ) used AAV-Nat8l-shRNA, an AAV vector carrying a short-hairpin RNA against Nat8l sequence driven by the U6 promoter that was administered into the cerebral ventricles and cisterna magna of AspaNur7/Nur7 mice on postnatal day 1. The treatment suppressed disease phenotype.…”