Cross-species efficacy of AAV-mediated ARSA replacement for metachromatic leukodystrophy
Shyam Ramachandran, Jeffery Ardinger, Jie Bu, MiAngela Ramos, Lilu Guo, Dhiman Ghosh, Mahmud Hossain, Shih-Ching Chou, Yao Chen, Erik Wischhof, Swathi Ayloo, Roger Trullo, Yuxia Luo, Jessica M. Hogestyn, Daniel M. DuBreuil, Emily Crosier, Johanna G. Flyer-Adams, Amy M. Richards, Michael Tsabar, Giorgio Gaglia, Shelley Nass, Bindu Nambiar, Denise Woodcock, Catherine O’Riordan, Qi Tang, Bradford Elmer, Bailin Zhang, Martin Goulet, Christian Mueller
Shyam Ramachandran, Jeffery Ardinger, Jie Bu, MiAngela Ramos, Lilu Guo, Dhiman Ghosh, Mahmud Hossain, Shih-Ching Chou, Yao Chen, Erik Wischhof, Swathi Ayloo, Roger Trullo, Yuxia Luo, Jessica M. Hogestyn, Daniel M. DuBreuil, Emily Crosier, Johanna G. Flyer-Adams, Amy M. Richards, Michael Tsabar, Giorgio Gaglia, Shelley Nass, Bindu Nambiar, Denise Woodcock, Catherine O’Riordan, Qi Tang, Bradford Elmer, Bailin Zhang, Martin Goulet, Christian Mueller
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Research Article Genetics Neuroscience

Cross-species efficacy of AAV-mediated ARSA replacement for metachromatic leukodystrophy

Abstract

Metachromatic leukodystrophy (MLD) is an autosomal recessive neurodegenerative disorder caused by mutations in the arylsulfatase A (ARSA) gene, resulting in lower sulfatase activity and the toxic accumulation of sulfatides in the central and peripheral nervous system. Children account for 70% of cases and become progressively disabled, with death occurring within 10 years of disease onset. Gene therapy approaches to restore ARSA expression via adeno-associated virus (AAV) vectors have been promising but hampered by limited brain biodistribution. We report the development of an engineered capsid, AAV.GMU01, demonstrating superior biodistribution and transgene expression in the central nervous system of nonhuman primates (NHPs). Next, we show that AAV.GMU01-ARSA–treated MLD mice exhibit persistent, normal levels of sulfatase activity and a concomitant reduction in toxic sulfatides. Treated mice also show a reduction in MLD-associated pathology and auditory dysfunction. Lastly, we demonstrate that treatment with AAV.GMU01-ARSA in NHPs is well tolerated and results in potentially therapeutic ARSA expression in the brain. In summary, we propose AAV.GMU01-ARSA–mediated gene replacement as a clinically viable approach to achieve broad and therapeutic levels of ARSA.

Authors

Shyam Ramachandran, Jeffery Ardinger, Jie Bu, MiAngela Ramos, Lilu Guo, Dhiman Ghosh, Mahmud Hossain, Shih-Ching Chou, Yao Chen, Erik Wischhof, Swathi Ayloo, Roger Trullo, Yuxia Luo, Jessica M. Hogestyn, Daniel M. DuBreuil, Emily Crosier, Johanna G. Flyer-Adams, Amy M. Richards, Michael Tsabar, Giorgio Gaglia, Shelley Nass, Bindu Nambiar, Denise Woodcock, Catherine O’Riordan, Qi Tang, Bradford Elmer, Bailin Zhang, Martin Goulet, Christian Mueller

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Figure 3

Phenotypic reversal in Arsa-KO mice treated with AAV.GMU01-ARSA.

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Phenotypic reversal in Arsa-KO mice treated with AAV.GMU01-ARSA. Pre-neu...
Pre-neuronopathic Arsa-KO mice and age-matched control animals were dosed with AAV.GMU01-ARSA at 1.6e11 VG/mouse (3.3e11 VG/g brain weight). Thirteen months after dose, Arsa-KO mice were euthanized, and brain, spinal cord, DRG, sciatic nerve, liver, plasma, and CSF samples were collected. (A and B) ARSA-mediated sulfatase activity was measured using the sulfatase activity assay; data normalized to total protein measured by bicinchoninic acid (BCA) assay. (C and D) Sulfatide levels were measured using liquid chromatography–mass spectrometry. Data normalized to tissue weight: converted from ng/mL (50 μL) to μg/g (ng ST/μg total protein for DRG and sciatic nerve). For fluids, data are presented as ng/mL (CSF). (E–G) RT-dPCR was performed to quantify Gfap, Aif1 (gene for Iba1), and Lamp1 levels, normalized to mouse Hprt gene. Each data point represents a single animal. Data are shown as the mean ± SEM; 1-way ANOVA with Tukey’s multiple-comparison test. (H) At 4, 7, 10, and 13 months after dose, ABR measurements were recorded via electrodes placed on the scalp of an anesthetized animal. Data are shown as the mean ± SEM; 2-way ANOVA with Tukey’s multiple-comparison test. #denotes “KO+FB” versus “KO+AAV” group; *denotes “WT+FB” versus “KO+FB” group. (I–K) Histopathological findings in brain, spinal cord, and DRG; each data point represents the maximum severity of findings scored on 1–2 sections per animal. Severity scores refer to findings graded as 0 = no findings, 1 = minimal, 2 = mild, 3 = moderate, 4 = marked, and 5 = severe. Data are shown as the mean ± SEM. */#P < 0.05; **/##P < 0.01; ***/###P < 0.001; ****/####P < 0.0001. FB, formulation buffer; ST, sulfatide.