Prunty, H. | 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↗

bioRxiv2018

Gene therapy in argininosuccinic aciduria

Argininosuccinate lyase (ASL) belongs to the liver-based urea cycle detoxifying ammonia, and the citrulline-nitric oxide cycle synthesising nitric oxide (NO). ASL-deficient patients present argininosuccinic aciduria characterised by hyperammonaemia and a multi-organ disease with neurocognitive impairment. Current therapeutic guidelines aim to control ammonaemia without considering the systemic NO imbalance. Here, we observed a neuronal disease with oxidative/nitrosative stress in ASL-deficient mouse brains. A single systemic injection of gene therapy mediated by an adeno-associated viral vector serotype 8 (AAV8) in adult or neonatal mice demonstrated the long-term correction of the urea cycle and the citrulline-NO cycle in the brain, respectively. The neuronal disease persisted if ammonaemia only was normalised but was dramatically reduced after correction of both ammonaemia and neuronal ASL activity. This was correlated with behavioural improvement and a decrease of the cortical cell death rate. Thus, the cerebral disease in argininosuccinic aciduria involves neuronal oxidative/nitrosative stress not mediated by hyperammonaemia, which is reversed by AAV gene transfer targeting the brain and the liver, acting on two different metabolic pathways via a single vector delivered systemically. This approach provides new hope for hepatocerebral metabolic diseases.

genetics↗