Adeno-Associated Virus Gene Therapy in a Sheep Model of Tay-Sachs Disease.

Tay-Sachs disease (TSD) is a fatal neurodegenerative disorder caused by a deficiency of the enzyme hexosaminidase A (HexA). TSD also occurs in sheep, the only experimental model of TSD that has clinical signs of disease. The natural history of sheep TSD was characterized using serial neurological evaluations, 7 Tesla magnetic resonance imaging, echocardiograms, electrodiagnostics, and cerebrospinal fluid biomarkers. Intracranial gene therapy was also tested using AAVrh8 monocistronic vectors encoding the α-subunit of Hex (TSD α) or a mixture of two vectors encoding both the α and ß subunits separately (TSD α + ß) injected at high (1.3 × 1013 vector genomes) or low (4.2 × 1012 vector genomes) dose. Delay of symptom onset and/or reduction of acquired symptoms were noted in all adeno-associated virus-treated sheep. Postmortem evaluation showed superior HexA and vector genome distribution in the brain of TSD α + ß sheep compared to TSD α sheep, but spinal cord distribution was low in all groups. Isozyme analysis showed superior HexA formation after treatment with both vectors (TSD α + ß), and ganglioside clearance was most widespread in the TSD α + ß high-dose sheep. Microglial activation and proliferation in TSD sheep-most prominent in the cerebrum-were attenuated after gene therapy. This report demonstrates therapeutic efficacy for TSD in the sheep brain, which is on the same order of magnitude as a child's brain.

Neuronal pentraxin 1 depletion delays neurodegeneration and extends life in Sandhoff disease mice.

GM2 gangliosidoses are a group of lysosomal storage disorders which include Sandhoff disease and Tay-Sachs disease. Dysregulation of glutamate receptors has been recently postulated in the pathology of Sandhoff disease. Glutamate receptor association with neuronal pentraxins 1 and 2, and the neuronal pentraxin receptor facilitates receptor potentiation and synaptic shaping. In this study, we have observed an upregulation of a novel form of neuronal pentraxin 1 (NP1-38) in the brains of a mouse model of Sandhoff disease and Tay-Sachs disease. In order to determine the impact of NP1 on the pathophysiology of Sandhoff disease mouse models, we have generated an Np1-/-Hexb-/- double knockout mouse, and observed extended lifespan, improved righting reflex and enhanced body condition relative to Hexb-/- mice, with no effect on gliosis or apoptotic markers in the CNS. Sandhoff mouse brain slices reveals a reduction in AMPA receptor-mediated currents, and increased variability in total glutamate currents in the CA1 region of the hippocampus; Np1-/-Hexb-/- mice show a correction of this phenotype, suggesting NP1-38 may be interfering with glutamate receptor function. Indeed, some of the psychiatric aspects of Sandhoff and Tay-Sachs disease (particularly late onset) may be attributed to a dysfunctional hippocampal glutamatergic system. Our work highlights a potential role for synaptic proteins, such as NP1 and glutamate receptors in lysosomal storage diseases.

Lysosome-related genes are regulated in the orbital fat of patients with graves' ophthalmopathy.

PURPOSE: The molecular mechanism involved in the hypertrophy of the orbital fat in patients with Graves' ophthalmopathy or thyroid eye disease (TED) remains unclear. Comparison of genome-wide expression profiles may help in the search for the gene sets involved in TED. METHODS: Twenty-five orbital adipose tissue specimens were obtained, from which the RNA was isolated. Four of the tissue specimens (from four individuals, two with TED and two control subjects) were subjected to cDNA microarray analysis. The data were analyzed by the gene set enrichment analysis (GSEA) to survey the biological pathways involved in the pathogenesis of TED. Messenger RNA levels of some top-ranked genes in GSEA-selected pathways are validated by quantitative PCR (QPCR). RESULTS: The expression of specific gene sets related to lytic vacuoles, lysosomes, and vacuoles were different between the specimens obtained from patients with TED and control subjects (P < 0.001). These three gene sets overlapped. For QPCR, four top-ranked genes were selected from these overlapping gene sets and another one that related to visual failure, using 21 independent samples of patients with TED (n = 15) and control subjects (n = 6). The results showed that ceroid-lipofuscinosis, neuronal 2, late infantile (CLN2; P = 0.044) and ceroid-lipofuscinosis, neuronal 3, juvenile (CLN3, which related to visual failure; P = 0.012) were significantly downregulated in the orbital fat of patients with TED. The expression of the beta subunit of hexosaminidase A (HEXB) was reduced as well, but the change did not reach statistical significance (P = 0.058). CONCLUSIONS: Lysosome-related genes, such as CLN2, CLN3, and HEXB, may be involved in the pathogenesis of adipose tissue hypertrophy in TED.