Antinao Diaz, J. F. | Search bioRxiv

bioRxiv2024

GENE THERAPY PREVENTS HEPATIC MITOCHONDRIAL DYSFUNCTION IN MURINE DEOXYGUANOSINE KINASE DEFICIENCY

Primary mitochondrial disorders are an uncommon cause of neonatal hepatic failure. Biallelic pathogenic variants of the gene encoding the mitochondrial localising enzyme deoxyguanosine kinase (DGUOK) cause hepatocerebral mitochondrial DNA depletion syndrome leading to acute neonatal liver failure and early mortality. There are currently no effective disease-modifying therapies. In this study, we developed an adeno-associated virus 9 (AAV9) gene therapy approach to treat a mouse model of DGUOK deficiency that recapitulates human disease. We delivered AAV9-hDGUOK gene therapy intravenously to newborn Dguok knock-out mice and showed that liver dysfunction was prevented in a dose dependent manner. Unexpectedly for neonatal delivery, durable and long-lasting liver transduction and RNA expression were demonstrated. Liver mitochondrial DNA depletion, deficiencies of oxidative phosphorylation complexes I, III and IV and liver transaminitis and survival were ameliorated in a dose-dependent manner.

genetics↗

bioRxiv2023

Spinal cord pathology in a Dravet Syndrome mouse model

SummaryO_ST_ABSObjectivesC_ST_ABSDravet syndrome is a severe epileptic encephalopathy that begins in early childhood. More than 80% of patients with Dravet syndrome exhibit a haploinsufficiency in SCN1A, which encodes the voltage-gated sodium ion channel NaV1.1. The epilepsy is believed be caused by specific deficit of SCN1A in inhibitory interneurons of the hippocampus. However, the aetiology of other symptoms including gait disturbances, ataxia, cardiac issues and dysautonomia is less clear. MethodsIn an Scn1a knock-out (Scn1a-/-) mouse model which recapitulates clinical phenotypes, we assessed NaV1.1 and neuroinflammation throughout the central nervous system. ResultsConsistent with current understanding, wild-type expression of NaV1.1 transcript and protein were absent in knock-out mice in the prefrontal cortex, striatum, hippocampus, thalamus, and cerebellum. Increased GFAP was detected in the brain only in the hippocampus. Transcript and protein were detected in wild-type cervical, thoracic and lumbar spinal cord but not in knock-out mice. Unexpectedly, GFAP was increased in all three spinal regions. Therefore, we proceeded to perform transcriptomic analysis of cortex, hippocampus and spinal cord. Pathways associated with monooxygenase activity, fatty acid ligases and lactate transporters were highly dysregulated in the spinal cord. ConclusionThe existence and relevance of pathology of the spinal cord in Dravet syndrome has received scant attention. Our findings are consistent with some systemic symptoms of Dravet syndrome, with the benefits of treatments which may modulate the astrocyte-neuron lactate shuttle such as Stiripentol and ketogenic dietary regimes, and with the efficacy of intrathecal delivery of therapeutics. Key PointsO_LIDecrease of endogenous Scn1a and NaV1.1 expression in Scn1a-/- mice has a widespread impact on the gene expression profile in the spinal cord. C_LIO_LIIncreased GFAP expression observed in the spinal cord of Scn1a-/- mice. C_LIO_LIDifferentially expressed genes related to monooxygenase activity, fatty acid ligases and lactate transporters in cervical spinal cord of Scn1a-/- mice. C_LI

molecular biology↗